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AcetamideAcetamid
acetamida
Acetic acid amide
Acetimidic acid
Ethanamide
Ethanimidic acid
Methanecarboxamide
NSC 25945
DTXSID7020005103-90-2RZVAJINKPMORJF-UHFFFAOYSA-NRZVAJINKPMORJF-UHFFFAOYSA-N
Acetaminophen4-Acetamidophenol
APAP
Paracetamol
4-hydroxyacetanilide
Acetamide, N-(4-hydroxyphenyl)-
4-(Acetylamino)phenol
4-(N-Acetylamino)phenol
4-Acetaminophenol
4'-Hydroxyacetanilide
Abensanil
Acetagesic
Acetalgin
ACETAMIDE, N-(4-HYDROXYPHENYL)
Acetaminofen
Acetanilide, 4'-hydroxy-
ACETANILIDE, 4-HYDROXY-
Algotropyl
Alvedon
Anaflon
Apamide
Banesin
Ben-u-ron
Bickie-mol
Biocetamol
Cetadol
Citramon P
Claratal
Clixodyne
Dafalgan
Daphalgan
Dial-a-gesic
Disprol
Doliprane
Dolprone
Dymadon
Efferalgan
Endophy
Febrilex
Febrilix
Febro-Gesic
Febrolin
Fepanil
Finimal
Gattaphen T
Gelocatil
Gutte Enteric
Homoolan
Jin Gang
Lestemp
Liquagesic
Lonarid
Lyteca Syrup
Minoset
Momentum
N-(4-Hydroxyphenyl)acetamide
N-Acetyl-4-aminophenol
N-Acetyl-4-hydroxyaniline
N-Acetyl-p-aminophenol
Napafen
Naprinol
Nobedon
NSC 109028
NSC 3991
Ortensan
p-(Acetylamino)phenol
p-Aceaminophenol
Pacemol
p-Acetamidophenol
p-Acetoaminophen
P-ACETYLAMINOPHENOL
Paldesic
panadeine
Panadol
Panadol Actifast
Panadol Extend
Panaleve
Panasorb
Panodil
Paracetamol DC
Paracetamole
Parageniol
Paramol
Paraspen
Parelan
Pasolind N
Perfalgan
Phenaphen
Phendon
p-Hydroxyacetanilide
Prodafalgan
Puerxitong
Pyrinazine
Resfenol
Resprin
Rhodapop NCR
Salzone
Tabalgin
Tachipirina
Tempanal
Tralgon
Tylenol
TylolHot
Valadol
Valgesic
Vermidon
Vick Pyrena
DTXSID2020006968-81-0VGZSUPCWNCWDAN-UHFFFAOYSA-NVGZSUPCWNCWDAN-UHFFFAOYSA-N
AcetohexamideBenzenesulfonamide, 4-acetyl-N-[(cyclohexylamino)carbonyl]-
1-(p-Acetylbenzenesulfonyl)-3-cyclohexylurea
1-[(p-Acetylphenyl)sulfonyl]-3-cyclohexylurea
Acetohexamid
acetohexamida
Dimelin
Dimelor
Dymelor
Gamadiabet
Hypoglicil
Metaglucina
Minoral
N-(p-Acetylphenylsulfonyl)-N'-cyclohexylurea
Ordimel
Tsiklamid
Urea, 1-[(p-acetylphenyl)sulfonyl]-3-cyclohexyl-
DTXSID702000767-66-3HEDRZPFGACZZDS-UHFFFAOYSA-NHEDRZPFGACZZDS-UHFFFAOYSA-N
ChloroformTrichloromethane
Methane, trichloro-
CARBON TRICHLORIDE
Chloroforme
cloroformo
Formyl trichloride
Methane trichloride
Methane,trichloro-
NSC 77361
Trichloroform
UN 1888
DTXSID1020306110-00-9YLQBMQCUIZJEEH-UHFFFAOYSA-NYLQBMQCUIZJEEH-UHFFFAOYSA-N
FuranDivinylene oxide
furanne
Furfuran
Oxacyclopentadiene
Tetrole
UN 2389
DTXSID60206467429-90-5XAGFODPZIPBFFR-UHFFFAOYSA-NAZDRQVAHHNSJOQ-UHFFFAOYSA-N
AluminumAisin Metal Fiber
Al 050P-H24
ALC Fine
Alcan XI 1391
Almi-Paste SSP 303AR
Aloxal 3010
Alpaste 00-0506
Alpaste 0100M
Alpaste 0100MA
Alpaste 0100M-C
Alpaste 0200M
Alpaste 0200T
Alpaste 0230M
Alpaste 0230T
Alpaste 0241M
Alpaste 0300M
Alpaste 0500M
Alpaste 0539X
Alpaste 0620MS
Alpaste 0625TS
Alpaste 0638-70C
Alpaste 0700M
Alpaste 0780M
Alpaste 0900M
Alpaste 100M
Alpaste 100MS
Alpaste 100MSR
Alpaste 1100M
Alpaste 1100MA
Alpaste 1100N
Alpaste 1100NA
Alpaste 1109MA
Alpaste 1109MC
Alpaste 1200M
Alpaste 1200T
Alpaste 1260MS
Alpaste 1500MA
Alpaste 1700NL
Alpaste 1810YL
Alpaste 1830YL
Alpaste 1900M
Alpaste 1900XS
Alpaste 1950M
Alpaste 1950N
Alpaste 210N
Alpaste 2172EA
Alpaste 2173
Alpaste 240T
Alpaste 241M
Alpaste 417
Alpaste 46-046
Alpaste 4-621
Alpaste 4919
Alpaste 50-63
Alpaste 50-635
Alpaste 51-148B
Alpaste 51-231
Alpaste 5205N
Alpaste 5207N
Alpaste 52-509
Alpaste 52-568
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Alpaste 54-452
Alpaste 54-497
Alpaste 54-542
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Alpaste 55-574
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Alpaste 56-501
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Alpaste 5654NS
Alpaste 5680N
Alpaste 5680NS
Alpaste 60-600
Alpaste 60-760
Alpaste 60-768
Alpaste 62-356
Alpaste 6340NS
Alpaste 6370NS
Alpaste 6390NS
Alpaste 640NS
Alpaste 65-388
Alpaste 66NLB
Alpaste 710N
Alpaste 7130N
Alpaste 7160N
Alpaste 7160NS
Alpaste 725N
Alpaste 740NS
Alpaste 7430NS
Alpaste 7580NS
Alpaste 7620NS
Alpaste 7640NS
Alpaste 7670M
Alpaste 7670NS
Alpaste 7675NS
Alpaste 7679NS
Alpaste 7680N
Alpaste 7680NS
Alpaste 76840NS
Alpaste 7730N
Alpaste 7770N
Alpaste 7830N
Alpaste 8004
Alpaste 8080N
Alpaste 8260NAR
Alpaste 891K
Alpaste 91-0562
Alpaste 92-0592
Alpaste 93-0595
Alpaste 93-0647
Alpaste 94-2315
Alpaste 95-0570
Alpaste 96-0635
Alpaste 96-2104
Alpaste 97-0510
Alpaste 97-0534
Alpaste AW 520B
Alpaste AW 612
Alpaste AW 9800
Alpaste F 795
Alpaste FM 7680K
Alpaste FX 440
Alpaste FX 910
Alpaste FZ 0534
Alpaste FZU 40C
Alpaste G
Alpaste HR 8801
Alpaste HS 2
Alpaste J
Alpaste K 9800
Alpaste MC 666
Alpaste MC 707
Alpaste MF 20
Alpaste MG 01
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Alpaste MG 1300
Alpaste MG 500
Alpaste MG 600
Alpaste MH 6601
Alpaste MH 8801
Alpaste MH 9901
Alpaste MR 7000
Alpaste MR 9000
Alpaste MS 630
Alpaste N 1700NL
Alpaste NS 7670
Alpaste O 100N
Alpaste O 2130
Alpaste O 300M
Alpaste P 0100
Alpaste P 1950
Alpaste S
Alpaste SAP 110
Alpaste SAP 414P
Alpaste SAP 550N
Alpaste SCR 5070
Alpaste TCR 2020
Alpaste TCR 2060
Alpaste TCR 2070
Alpaste TCR 3010
Alpaste TCR 3030
Alpaste TCR 3040
Alpaste TCR 3130
Alpaste TD 200T
Alpaste UF 500
Alpaste WB 0230
Alpaste WD 500
Alpaste WJP-U 75C
Alpaste WX 0630
Alpaste WX 7830
Alpaste WXA 7640
Alpaste WXM 0630
Alpaste WXM 0650
Alpaste WXM 0660
Alpaste WXM 1415
Alpaste WXM 1440
Alpaste WXM 5422
Alpaste WXM 760b
Alpaste WXM 7640
Alpaste WXM 7675
Alpaste WXM-T 60B
Alpaste WXM-U 75
Alpaste WXM-U 75C
Altop X
Aluchrome Ultrafin Super
Alumat 1600
Alumet H 30
aluminio
Aluminium
Aluminium Flake
Aluminum 27
Aluminum atom
Aluminum element
Aluminum Flake PCF 7620
Aluminum granules
ALUMINUM METAL/GRANULE
ALUMINUM PASTE
ALUMINUM PIGMENT
ALUMINUM TURNINGS
Alumi-paste 640NS
Alumipaste 91-0562
Alumipaste 98-1822T
Alumipaste AW 620
Alumipaste CR 300
Alumipaste GX 180A
Alumipaste GX 201A
Alumipaste HR 7000
Alumipaste HR 850
Alumipaste MG 11
Alumipaste MH 8801
Aquamet NPW 2900
Aquapaste 205-5
Aquasilver LPW
Astroflake 40
Astroflake Black N 020
Astroflake Black N 070
Astroflake LG 40
Astroflake LG 70
Astroflake Silver N 040
Astroshine NJ 1600
Astroshine T 8990
Atomizalumi VA 200
C.I. PIGMENT METAL 1
Chromal IV
Chromal X
Decomet 1001/10
Decomet 2018/10
Decomet High Gloss Al 1002/10
Ecka AS 081
Eckart 9155
Eterna Brite 301-1
Eterna Brite 601-1
Eterna Brite 651-1
Eterna Brite EBP 251PA
Eterna Brite Primier 251PA
Ferro FX 53-038
Friend Color F 500GR-W
Friend Color F 500WT
Friend Color F 700RE-W
Friend Color F 701RE-W
Hi Print 60T
High Print 60T
Hisparkle HS 2
Hydro Paste 8726
Hydrolac WHH 2153
Hydrolan 3560
Hydrolux Reflexal 100
Hydroshine WS 1001
JISA 51010P
Kryal Z
Lansford 243
LE Sheet 800
Leafing Alpaste
LG-H Silver 25
Lunar Al-V 95
Metallux 161
Metallux 2154
Metallux 2192
Metalure
Metalure 55350
Metalure L 55350
Metalure L 59510
Metalure W 2001
Metapor
Metasheen 1800
Metasheen HR 0800
Metasheen KM 100
Metasheen KM 1000
Metasheen Slurry 1807
Metasheen Slurry 1811
Metasheen Slurry KM 100
Metax G
Metax S
Mirror Glow 1000
Mirror Glow 600
Mirrorsheen
Noral Aluminium
Noral Ink Grade Aluminium
Obron 10890
Offset FM 4500
Puratronic
Reflexal 145
Reynolds 400
Reynolds 4-301
Reynolds 4-591
Reynolds 667
SAP 260PW-HS
SAP-FM 4010
SBC 516-20Z
Scotchcal 7755SE
Serumekku
Setanium 50MIS-H8
Siberline ET 2025
Siberline ST 21030E1
Silvar A
Silver VT 522
Silverline SSP 353
Silvex 793-20C
Sparkle Silver 3141ST
Sparkle Silver 3500
Sparkle Silver 3641
Sparkle Silver 5000AR
Sparkle Silver 516AR
Sparkle Silver 5242AR
Sparkle Silver 5245AR
Sparkle Silver 5271AR
Sparkle Silver 5500
Sparkle Silver 5745
Sparkle Silver 7000AR
Sparkle Silver 7005AR
Sparkle Silver 7500
Sparkle Silver 960-25E1
Sparkle Silver E 1745AR
Sparkle Silver L 1526AR
Sparkle Silver Premier 751
Sparkle Silver SS 3130
Sparkle Silver SS 5242AR
Sparkle Silver SS 5588
Sparkle Silver SSP 132AR
Special PCR 507
Splendal 6001BG
Spota Mobil 801
SSP 760-20C
Stapa Aloxal PM 2010
Stapa Aloxal PM 3010
Stapa Aloxal PM 4010
Stapa Hydrolac BG 8n.1
Stapa Hydrolac BGH Chromal X
Stapa Hydrolac PM Chromal VIII
Stapa Hydrolac W 60NL
Stapa Hydrolac WH 16
Stapa Hydrolac WH 66NL
Stapa Hydrolux 2192
Stapa Hydrolux 8154
Stapa IL Hydrolan 2192-55900G
Stapa Metallic R 607
Stapa Metallux 1050
Stapa Metallux 211
Stapa Metallux 212
Stapa Metallux 2196
Stapa Metallux 274
Stapa Mobilux 181
Stapa Offset 3000
Stapa PV 10
Stapa VP 46432G
Starbrite 2100
Super Fine 18000
Super Fine 22000
Supramex 2022
Toyo Aluminum 02-0005
Toyo Aluminum 93-3040
Transmet K 102HE
Tufflake 3645
Tufflake 5843
UN 1396
US Aluminum 809
Valimet H 2
Valimet H 3
White Silver 7080N
White Silver 7130N
DTXSID30402737440-43-9BDOSMKKIYDKNTQ-UHFFFAOYSA-NBDOSMKKIYDKNTQ-UHFFFAOYSA-N
CadmiumCadimium
CADMIUM BLUE
CADMIUM, IN PLATTEN, STANGEN, BROCKEN,KOERNER
DTXSID10239407439-97-6QSHDDOUJBYECFT-UHFFFAOYSA-NQSHDDOUJBYECFT-UHFFFAOYSA-N
MercuryLiquid silver
Mercure
MERCURIC METAL TRIPLE DISTILLED
mercurio
Mercury element
Quecksilber
Quicksilver
UN 2024
UN 2809
DTXSID10241727440-61-1JFALSRSLKYAFGM-UHFFFAOYSA-NJFALSRSLKYAFGM-UHFFFAOYSA-N
UraniumUranium, isotope of mass 238
238U Element
UN 2979 (DOT)
Uranium I
DTXSID10425227440-38-2RQNWIZPPADIBDY-UHFFFAOYSA-NRQNWIZPPADIBDY-UHFFFAOYSA-N
ArsenicAs
Arsenic black
ARSENIC METAL
arsenico
Grey arsenic
UN 1558
DTXSID40238867440-22-4BQCADISMDOOEFD-UHFFFAOYSA-NBQCADISMDOOEFD-UHFFFAOYSA-N
SilverAg Nanopaste NPS-J 90
Ag Sphere 2
Ag-C-GS
Algaedyn
Arctic Silver 3
Argentum
Astroflake 5
Carey Lea silver
Colloidal silver
Dotite XA 208
Du Pont 4943
ECM 100AF4810
Enlight 600
Enlight silver plate 600
Epinall
Finesphere SVND 102
Fordel DC
FP 5369-502
Jelcon SH 1
Jungindai Takasago 300
KS (metal)
LCP 1-19SFS
Metz 3000-1
Nanomelt AGC-A
Nanomelt Ag-XA 301
Nanomelt Ag-XF 301
Nanomelt Ag-XF 301H
Nanopaste NPS-J 90
Perfect Silver
Puff Silver X 1200
RT 1710S-C1
SD (metal)
Shell Silver
Silbest E 20
Silbest F 20
Silbest J 18
Silbest TC 12
Silbest TC 20E
Silbest TC 25A
Silbest TCG 1
Silbest TCG 7
Silcoat AgC 103
Silcoat AgC 2011
Silcoat AgC 209
Silcoat AgC 2190
Silcoat AgC 222
Silcoat AgC 2411
Silcoat AgC 74T
Silcoat AgC-A
Silcoat AgC-AO
Silcoat AgC-B
Silcoat AgC-BO
Silcoat AgC-D
Silcoat AgC-G
Silcoat AgC-GS
Silcoat AgC-L
Silcoat AgC-O
Silcoat GS
Silcoat RF 200
Silflake 135
Silsphere 514
Silver atom
Silver element
Silver Flake 1
Silver Flake 25
Silver Flake 52
Silver Flake 7A
SILVER FLAKES
Silver metal
Silvest TCG 11N
Technic 299
Technic 450
Techno Alpha 175
DTXSID40243057439-96-5PWHULOQIROXLJO-UHFFFAOYSA-NPWHULOQIROXLJO-UHFFFAOYSA-N
ManganeseColloidal manganese
Cutaval
Manganese element
Manganese fulleride
Manganese metal alloy
Manganese-55
manganeso
DTXSID20241697440-02-0PXHVJJICTQNCMI-UHFFFAOYSA-NPXHVJJICTQNCMI-UHFFFAOYSA-N
NickelCarbonyl 255
Carbonyl Ni 123
Carbonyl Ni 283
Carbonyl Nickel 123
Carbonyl Nickel 283
Carbonyl Nickel 287
Cerac N 2003
CNS 10 Micron
Exmet 4 Ni X-4/0
Fibrex P
Incofoam
Nickel element
NICKEL ROUND ANODES
Nicrobraz LM:BNi 2
Ni-Flake 95
Novamet 123
Novamet 4SP
Novamet 4SP10
Novamet 525
Novamet CNS 400
Novamet HCA 1
Novamet NI 255
Raney nickel
Raney nickel 2800
UN 1325
UN 2881
DTXSID20209257440-66-6HCHKCACWOHOZIP-UHFFFAOYSA-NHCHKCACWOHOZIP-UHFFFAOYSA-N
ZincZn
Asarco L 15
C.I. Pigment Black 16
Merrillite
NC-Zinc
Rheinzink
Stapa TE Zinc AT
UF (metal)
UN 1436
Zinc dust
Zinc Dust 3
Zinc Dust 500 mesh
Zinc Dust LS 2
Zinc Dust MCS
Zinc Flakes GTT
ZINC METAL
ZINC MOSSY
ZINC STRIP
ZINC, MOSSY
Zincsalt GTT
DTXSID7035012CL:0000129microglial cellCL:0000127astrocyteMP:0003674oxidative stressGO:0099536synaptic signalingMP:0001847brain inflammation1increased2decreased11pathologicalAcetaminophen2016-11-29T18:42:262016-11-29T18:42:26Chloroform2016-11-29T18:42:272016-11-29T18:42:27furan2020-05-01T14:35:222020-05-01T14:35:22Platinum2022-02-04T14:36:542022-02-04T14:36:54Aluminum2022-02-04T14:42:112022-02-04T14:42:11Cadmium2017-10-25T08:33:122017-10-25T08:33:12Mercury2016-11-29T18:42:192016-11-29T18:42:19Uranium2021-08-05T14:28:502021-08-05T14:28:50Arsenic2021-04-27T00:15:212021-04-27T00:15:21Silver 2022-02-03T11:20:112022-02-03T11:20:11Manganese2022-02-04T14:47:232022-02-04T14:47:23Nickel2022-02-04T14:47:592022-02-04T14:47:59Zinc2022-02-04T15:05:002022-02-04T15:05:00nanoparticles2016-12-21T09:40:062016-12-21T09:40:06SARS-CoV2020-03-01T10:42:462020-03-01T10:42:46Sars-CoV-2<p>Virus from the coronaviridae family related to SARS-CoV, 229E, NL63, OC43, HKU1 and MERS.</p>
<p>Transmitted by aerosols</p>
2021-02-23T04:50:402022-09-09T05:09:36Chemical2017-02-07T13:22:422017-02-07T13:22:42Virus2018-05-29T07:10:012018-05-29T07:10:01bacteria2021-02-23T05:15:412021-02-23T05:15:41WikiUser_26rodents9606Homo sapiensWCS_9606humans10116rat10095mice9685cat10090mouseWCS_9606humanWCS_7955zebrafish9541Macaca fascicularisMitochondrial dysfunctionMitochondrial dysfunctionCellular2020-11-02T07:11:182020-11-02T07:11:18Oxidative Stress Oxidative Stress Molecular<p style="text-align:justify">Oxidative stress is defined as an imbalance in the production of reactive oxygen species (ROS) and antioxidant defenses. High levels of oxidizing free radicals can be very damaging to cells and molecules within the cell (Pizzino et al., 2017; Sharifi-Rad et al., 2020; Jena et al., 2023). As a result, the cell has important defense mechanisms to protect itself from ROS. For example, Nrf2 is a transcription factor and master regulator of the oxidative stress response. During periods of oxidative stress, Nrf2-dependent changes in gene expression are important in regaining cellular homeostasis (Nguyen, et al. 2009) and can be used as indicators of the presence of oxidative stress in the cell.</p>
<p style="text-align:justify">In addition to the directly damaging actions of ROS, cellular oxidative stress also changes cellular activities on a molecular level. Redox sensitive proteins have altered physiology in the presence and absence of ROS, which is caused by the oxidation of sulfhydryls to disulfides (2SH àSS) on neighboring amino acids (Antelmann and Helmann 2011). Importantly Keap1, the negative regulator of Nrf2, is regulated in this manner (Itoh, et al. 2010).</p>
<p><span style="font-size:16px"><span style="background-color:white"><span style="color:#2f5597">ROS also undermine the mitochondrial defense system from oxidative damage. The antioxidant systems consist of superoxide dismutase, <span style="background-color:white">catalase, glutathione peroxidase and glutathione reductase, as well as antioxidants such as α-tocopherol and ubiquinol</span></span></span><span style="color:#2f5597">, or antioxidant vitamins and minerals including vitamin E, C, carotene, lutein, zeaxanthin, selenium, and zinc (Fletcher, 2010). The enzymes, vitamins and minerals catalyze the conversion of ROS to non-toxic molecules such as water and O<sub>2</sub></span><span style="background-color:white"><span style="color:#2f5597"><span style="background-color:white">. However, these antioxidant systems are not perfect and endogenous metabolic processes and/or exogenous oxidative influences can trigger cumulative oxidative injuries to the mitochondria, causing a decline in their functionality and efficiency, which further promotes cellular oxidative stress (</span></span></span></span><span style="color:#2f5597">Balasubramanian, 2000; Ganea & Harding, 2006; Guo et al., 2013; Karimi et al., 2017)<span style="font-size:16px"><span style="background-color:white"><span style="background-color:white">.</span></span></span></span></p>
<p><span style="color:#27ae60"><span style="font-size:18px"><span style="background-color:white"><span style="font-family:"Times New Roman",serif"><span style="font-family:"Calibri",sans-serif"><span style="background-color:white">However, an emerging viewpoint suggests that ROS-induced modifications may not be as detrimental as previously thought, but rather contribute to signaling processes (Foyer et al., 2017). </span></span></span></span></span></span></p>
<p style="text-align:justify">Protection against oxidative stress is relevant for all tissues and organs, although some tissues may be more susceptible. For example, the brain possesses several key physiological features, such as high O2 utilization, high polyunsaturated fatty acids content, presence of autooxidable neurotransmitters, and low antioxidant defenses as compared to other organs, that make it highly susceptible to oxidative stress (Halliwell, 2006; Emerit and al., 2004; Frauenberger et al., 2016).</p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="color:#2f5597">Sources of ROS Production</span></span></strong></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="color:#2f5597">Direct Sources:</span></span></strong><span style="font-size:12.0pt"><span style="color:#2f5597"> Direct sources involve the deposition of energy onto water molecules, breaking them into active radical species. When ionizing radiation hits water, it breaks it into hydrogen (H*) and hydroxyl (OH*) radicals by destroying its bonds. The hydrogen will create hydroxyperoxyl free radicals (HO<sub>2</sub>*) if oxygen is available, which can then react with another of itself to form hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) and more O<sub>2</sub> (Elgazzar and Kazem, 2015). Antioxidant mechanisms are also affected by radiation, with catalase (CAT) and peroxidase (POD) levels rising as a result of exposure (Seen et al. 2018; Ahmad et al. 2021). </span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="color:#2f5597">Indirect Sources:</span></span></strong><span style="font-size:12.0pt"><span style="color:#2f5597"> An indirect source of ROS is the mitochondria, which is one of the primary producers in eukaryotic cells (Powers et al., 2008). As much as 2% of the electrons that should be going through the electron transport chain in the mitochondria escape, allowing them an opportunity to interact with surrounding structures. Electron-oxygen reactions result in free radical production, including the formation of hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) (Zhao et al., 2019). The electron transport chain, which also creates ROS, is activated by free adenosine diphosphate (ADP), O<sub>2</sub>, and inorganic phosphate (P<sub>i</sub>) (Hargreaves et al. 2020; Raimondi et al. 2020; Vargas-Mendoza et al. 2021). The first and third complexes of the transport chain are the most relevant to mammalian ROS production (Raimondi et al., 2020). The mitochondria have its own set of DNA and it is a prime target of oxidative damage (Guo et al., 2013). ROS are also produced through nicotinamide adenine dinucleotide phosphate oxidase (NOX) stimulation, an event commenced by angiotensin II, a product/effector of the renin-angiotensin system (Nguyen Dinh Cat et al. 2013; Forrester et al. 2018). Other ROS producers include xanthine oxidase, immune cells (macrophage, neutrophils, monocytes, and eosinophils), phospholipase A<sub>2</sub> (PLA<sub>2</sub>), monoamine oxidase (MAO), and carbon-based nanomaterials (Powers et al. 2008; Jacobsen et al. 2008; Vargas-Mendoza et al. 2021).</span></span></span></span></p>
<p><strong>Oxidative Stress. Direct measurement of ROS is difficult because ROS are unstable. The presence of ROS can be assayed indirectly by measurement of cellular antioxidants, or by ROS-dependent cellular damage.</strong><span style="color:#27ae60"> Listed below are common methods for detecting the KE, however there may be other comparable methods that are not listed</span></p>
<ul>
<li>Detection of ROS by chemiluminescence <span style="font-size:12px">(<span style="font-family:arial,helvetica,sans-serif">https://www.sciencedirect.com/science/article/abs/pii/S0165993606001683)</span></span></li>
<li>Detection of ROS by chemiluminescence is also described in OECD TG 495 to assess phototoxic potential.</li>
<li>Glutathione (GSH) depletion. GSH can be measured by assaying the ratio of reduced to oxidized glutathione (GSH:GSSG) using a commercially available kit (e.g., http://www.abcam.com/gshgssg-ratio-detection-assay-kit-fluorometric-green-ab138881.html). </li>
<li>TBARS. Oxidative damage to lipids can be measured by assaying for lipid peroxidation using TBARS (thiobarbituric acid reactive substances) using a commercially available kit. </li>
<li>8-oxo-dG. Oxidative damage to nucleic acids can be assayed by measuring 8-oxo-dG adducts (for which there are a number of ELISA based commercially available kits),or HPLC, described in Chepelev et al. (Chepelev, et al. 2015).</li>
</ul>
<p><strong>Molecular Biology: Nrf2. Nrf2’s transcriptional activity is controlled post-translationally by oxidation of Keap1. Assay for Nrf2 activity include:</strong></p>
<ul>
<li>Immunohistochemistry for increases in Nrf2 protein levels and translocation into the nucleus</li>
<li>Western blot for increased Nrf2 protein levels</li>
<li>Western blot of cytoplasmic and nuclear fractions to observe translocation of Nrf2 protein from the cytoplasm to the nucleus</li>
<li>qPCR of Nrf2 target genes (e.g., Nqo1, Hmox-1, Gcl, Gst, Prx, TrxR, Srxn), or by commercially available pathway-based qPCR array (e.g., oxidative stress array from SABiosciences)</li>
<li>Whole transcriptome profiling by microarray or RNA-seq followed by pathway analysis (in IPA, DAVID, metacore, etc.) for enrichment of the Nrf2 oxidative stress response pathway (e.g., Jackson et al. 2014)</li>
<li>OECD TG422D describes an ARE-Nrf2 Luciferase test method</li>
<li>In general, there are a variety of commercially available colorimetric or fluorescent kits for detecting Nrf2 activation</li>
</ul>
<p> </p>
<table border="1" cellpadding="1" cellspacing="1">
<tbody>
<tr>
<td><strong>Assay Type & Measured Content</strong></td>
<td><strong>Description</strong></td>
<td><strong>Dose Range Studied</strong></td>
<td>
<p><strong>Assay Characteristics </strong><strong>(Length / Ease of use/Accuracy)</strong></p>
</td>
</tr>
<tr>
<td>
<p><strong>ROS Formation in the Mitochondria assay</strong> (Shaki et al., 2012)</p>
</td>
<td>“The mitochondrial ROS measurement was performed flow cytometry using DCFH-DA. Briefly, isolated kidney mitochondria were incubated with UA (0, 50, 100 and 200 μM) in respiration buffer containing (0.32 mM sucrose, 10 mM Tris, 20 mM Mops, 50 μM EGTA, 0.5 mM MgCl2, 0.1 mM KH2PO4 and 5 mM sodium succinate) [32]. In the interval times of 5, 30 and 60 min following the UA addition, a sample was taken and DCFH-DA was added (final concentration, 10 μM) to mitochondria and was then incubated for 10 min. Uranyl acetate-induced ROS generation in isolated kidney mitochondria were determined through the flow cytometry (Partec, Deutschland) equipped with a 488-nm argon ion laser and supplied with the Flomax software and the signals were obtained using a 530-nm bandpass filter (FL-1 channel). Each determination is based on the mean fluorescence intensity of 15,000 counts.”</td>
<td>0, 50, 100 and 200 μM of Uranyl Acetate</td>
<td>
<p>Long/ Easy</p>
<p>High accuracy</p>
</td>
</tr>
<tr>
<td>
<p><strong>Mitochondrial Antioxidant Content Assay</strong> Measuring GSH content</p>
(Shaki et al., 2012)</td>
<td>“GSH content was determined using DTNB as the indicator and spectrophotometer method for the isolated mitochondria. The mitochondrial fractions (0.5 mg protein/ml) were incubated with various concentrations of uranyl acetate for 1 h at 30 °C and then 0.1 ml of mitochondrial fractions was added into 0.1 mol/l of phosphate buffers and 0.04% DTNB in a total volume of 3.0 ml (pH 7.4). The developed yellow color was read at 412 nm on a spectrophotometer (UV-1601 PC, Shimadzu, Japan). GSH content was expressed as μg/mg protein.”</td>
<td>
<p>0, 50, 100, or 200 <em>μ</em>M Uranyl Acetate</p>
</td>
<td> </td>
</tr>
<tr>
<td>
<p><strong>H<sub>2</sub>O<sub>2</sub> Production Assay</strong> Measuring H<sub>2</sub>O<sub>2</sub> Production in isolated mitochondria</p>
(Heyno et al., 2008)</td>
<td>“Effect of CdCl<sub>2</sub> and antimycin A (AA) on H<sub>2</sub>O<sub>2</sub> production in isolated mitochondria from potato. H<sub>2</sub>O<sub>2</sub> production was measured as scopoletin oxidation. Mitochondria were incubated for 30 min in the measuring buffer (see the Materials and Methods) containing 0.5 mM succinate as an electron donor and 0.2 µM mesoxalonitrile 3‐chlorophenylhydrazone (CCCP) as an uncoupler, 10 U horseradish peroxidase and 5 µM scopoletin.” (</td>
<td>
<p>0, 10, 30  <em>μ</em>M Cd<sup>2+</sup></p>
2  <em>μ</em>M<br />
antimycin A</td>
<td> </td>
</tr>
<tr>
<td>
<p><strong>Flow Cytometry ROS & Cell Viability</strong></p>
(Kruiderig et al., 1997)</td>
<td>“For determination of ROS, samples taken at the indicated time points were directly transferred to FACScan tubes. Dih123 (10 mM, final concentration) was added and cells were incubated at 37°C in a humidified atmosphere (95% air/5% CO2) for 10 min. At <em>t </em>5 9, propidium iodide (10 mM, final concentration) was added, and cells were analyzed by flow cytometry at 60 ml/min. Nonfluorescent Dih123 is cleaved by ROS to fluorescent R123 and detected by the FL1 detector as described above for Dc (Van de Water 1995)”</td>
<td> </td>
<td>
<p>Strong/easy</p>
medium</td>
</tr>
<tr>
<td>
<p><strong>DCFH-DA Assay</strong> Detection of hydrogen peroxide production (Yuan et al., 2016)</p>
</td>
<td>
<p>Intracellular ROS production was measured using DCFH-DA as a probe. Hydrogen peroxide oxidizes DCFH to DCF. The probe is hydrolyzed intracellularly to DCFH carboxylate anion. No direct reaction with H<sub>2</sub>O<sub>2 </sub>to form fluorescent production. </p>
</td>
<td>0-400 µM</td>
<td>
<p>Long/ Easy</p>
<p>High accuracy</p>
</td>
</tr>
<tr>
<td>
<p><strong>H2-DCF-DA Assay</strong> Detection of superoxide production (Thiebault et al., 2007)</p>
</td>
<td>This dye is a stable nonpolar compound which diffuses readily into the cells and yields H2-DCF. Intracellular OH or ONOO- react with H2-DCF when cells contain peroxides, to form the highly fluorescent compound DCF, which effluxes the cell. Fluorescence intensity of DCF is measured using a fluorescence spectrophotometer.</td>
<td>0–600 µM</td>
<td>
<p>Long/ Easy</p>
<p>High accuracy</p>
</td>
</tr>
<tr>
<td><strong>CM-H2DCFDA Assay</strong></td>
<td>**Come back and explain the flow cytometry determination of oxidative stress from Pan et al. (2009)**</td>
<td> </td>
<td> </td>
</tr>
</tbody>
</table>
<p>Direct Methods of Measurement</p>
<table cellspacing="0" class="Table" style="border-collapse:collapse; width:623px">
<tbody>
<tr>
<td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:141px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="color:#2f5597">Method of Measurement</span></span></strong> </span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:151px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="color:#2f5597">References</span></span></strong> </span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:255px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="color:#2f5597">Description</span></span></strong> </span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:1px solid black; vertical-align:top; width:76px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="color:#2f5597">OECD-Approved Assay</span></span></strong></span></span></p>
</td>
</tr>
<tr>
<td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:141px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Chemiluminescence </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:151px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Lu, C. et al., 2006; </span></span></span></span></p>
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Griendling, K. K., et al., 2016)</span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:255px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">ROS can induce electron transitions in molecules, leading to electronically excited products. When the electrons transition back to ground state, chemiluminescence is emitted and can be measured. Reagents such as uminol and lucigenin are commonly used to amplify the signal. </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:76px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></p>
<p> </p>
</td>
</tr>
<tr>
<td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:141px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Spectrophotometry </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:151px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Griendling, K. K., et al., 2016)</span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:255px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">NO has a short half-life. However, if it has been reduced to nitrite (NO2-), stable azocompounds can be formed via the Griess Reaction, and further measured by spectrophotometry. </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:76px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></p>
</td>
</tr>
<tr>
<td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:141px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Direct or Spin Trapping-Based Electron Paramagnetic Resonance (EPR) Spectroscopy </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:151px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Griendling, K. K., et al., 2016)</span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:255px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">The unpaired electrons (free radicals) found in ROS can be detected with EPR, and is known as electron paramagnetic resonance. A variety of spin traps can be used. </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:76px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></p>
</td>
</tr>
<tr>
<td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:141px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Nitroblue Tetrazolium Assay </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:151px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Griendling, K. K., et al., 2016)</span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:255px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">The Nitroblue Tetrazolium assay is used to measure O</span></span><sub><span style="font-size:12.0pt"><span style="color:#2f5597">2</span></span></sub><span style="background-color:white"><span style="color:#2f5597">•</span></span><sup><span style="font-size:12.0pt"><span style="color:#2f5597">–</span></span></sup><span style="font-size:12.0pt"><span style="color:#2f5597"> levels. O</span></span><sub><span style="font-size:12.0pt"><span style="color:#2f5597">2</span></span></sub><span style="background-color:white"><span style="color:#2f5597">•</span></span><sup><span style="font-size:12.0pt"><span style="color:#2f5597">–</span></span></sup><span style="font-size:12.0pt"><span style="color:#2f5597"> reduces nitroblue tetrazolium (a yellow dye) to formazan (a blue dye), and can be measured at 620 nm. </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:76px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></p>
</td>
</tr>
<tr>
<td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:141px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Fluorescence analysis of dihydroethidium (DHE) or Hydrocyans </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:151px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Griendling, K. K., et al., 2016)</span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:255px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Fluorescence analysis of DHE is used to measure O</span></span><sub><span style="font-size:12.0pt"><span style="color:#2f5597">2</span></span></sub><span style="background-color:white"><span style="color:#2f5597">•</span></span><sup><span style="font-size:12.0pt"><span style="color:#2f5597">–</span></span></sup><span style="font-size:12.0pt"><span style="color:#2f5597"> levels. O</span></span><sub><span style="font-size:12.0pt"><span style="color:#2f5597">2</span></span></sub><span style="background-color:white"><span style="color:#2f5597">•</span></span><sup><span style="font-size:12.0pt"><span style="color:#2f5597">–</span></span></sup><span style="font-size:12.0pt"><span style="color:#2f5597"> is reduced to O2 as DHE is oxidized to 2-hydroxyethidium, and this reaction can be measured by fluorescence. Similarly, hydrocyans can be oxidized by any ROS, and measured via fluorescence. </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:76px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></p>
</td>
</tr>
<tr>
<td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:141px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Amplex Red Assay </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:151px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Griendling, K. K., et al., 2016)</span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:255px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Fluorescence analysis to measure extramitochondrial or extracellular H<sub>2</sub>O<sub>2</sub> levels. In the presence of horseradish peroxidase and H<sub>2</sub>O<sub>2</sub>, Amplex Red is oxidized to resorufin, a fluorescent molecule measurable by plate reader. </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:76px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></p>
</td>
</tr>
<tr>
<td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:141px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Dichlorodihydrofluorescein Diacetate (DCFH-DA) </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:151px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Griendling, K. K., et al., 2016)</span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:255px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">An indirect fluorescence analysis to measure intracellular H<sub>2</sub>O<sub>2</sub> levels. H<sub>2</sub>O<sub>2</sub> interacts with peroxidase or heme proteins, which further react with DCFH, oxidizing it to dichlorofluorescein (DCF), a fluorescent product. </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:76px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></p>
</td>
</tr>
<tr>
<td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:141px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">HyPer Probe </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:151px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Griendling, K. K., et al., 2016)</span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:255px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Fluorescent measurement of intracellular H<sub>2</sub>O<sub>2</sub> levels. HyPer is a genetically encoded fluorescent sensor that can be used for <em>in vivo</em> and<em> in situ </em>imaging. </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:76px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></p>
</td>
</tr>
<tr>
<td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:141px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Cytochrome c Reduction Assay </span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:151px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Griendling, K. K., et al., 2016)</span></span></span></span></p>
</td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:255px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">The cytochrome c reduction assay is used to measure O</span></span><sub><span style="font-size:12.0pt"><span style="color:#2f5597">2</span></span></sub><span style="background-color:white"><span style="color:#2f5597">•</span></span><sup><span style="font-size:12.0pt"><span style="color:#2f5597">–</span></span></sup><span style="font-size:12.0pt"><span style="color:#2f5597"> levels. O</span></span><sub><span style="font-size:12.0pt"><span style="color:#2f5597">2</span></span></sub><span style="background-color:white"><span style="color:#2f5597">•</span></span><sup><span style="font-size:12.0pt"><span style="color:#2f5597">–</span></span></sup><span style="font-size:12.0pt"><span style="color:#2f5597"> is reduced to O2 as ferricytochrome c is oxidized to ferrocytochrome c, and this reaction can be measured by an absorbance increase at 550 nm. </span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Proton-electron double-resonance imagine (PEDRI)</span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Griendling, K. K., et al., 2016)</span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">The redox state of tissue is detected through nuclear magnetic resonance/magnetic resonance imaging, with the use of a nitroxide spin probe or biradical molecule. </span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Glutathione (GSH) depletion </span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Biesemann, N. et al., 2018) </span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="background-color:white"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">A downstream target of the Nrf2 pathway is involved in GSH synthesis. As an indication of oxidation status, GSH can be measured by assaying the ratio of reduced to oxidized glutathione (GSH:GSSG) using a commercially available kit (e.g., </span></span><span style="color:#2f5597"><a href="http://www.abcam.com/gshgssg-ratio-detection-assay-kit-fluorometric-green-ab138881.html"><span style="font-size:12.0pt"><span style="color:#2f5597">http://www.abcam.com/gshgssg-ratio-detection-assay-kit-fluorometric-green-ab138881.html</span></span></a></span><span style="font-size:12.0pt"><span style="color:#2f5597">). </span></span></span></span></span></p>
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<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:76px">
<p><span style="font-size:11pt"><span style="background-color:white"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Thiobarbituric acid reactive substances (TBARS) </span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Griendling, K. K., et al., 2016)</span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="background-color:white"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Oxidative damage to lipids can be measured by assaying for lipid peroxidation with TBARS using a commercially available kit. </span></span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="background-color:white"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Protein oxidation (carbonylation)</span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Azimzadeh et al., 2017; Azimzadeh etal., 2015; Ping et al., 2020)</span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Can be determined with enzyme-linked immunosorbent assay (ELISA) or a commercial assay kit. Protein oxidation can indicate the level of oxidative stress.</span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></p>
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<td style="border-bottom:1px solid black; border-left:1px solid black; border-right:1px solid black; border-top:none; vertical-align:top; width:141px"><span style="color:#27ae60">Seahorse XFp Analyzer </span></td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:151px"><span style="color:#27ae60">Leung et al. 2018 </span></td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:255px"><span style="color:#27ae60">The Seahorse XFp Analyzer provides information on mitochondrial function, oxidative stress, and metabolic dysfunction of viable cells by measuring respiration (oxygen consumption rate; OCR) and extracellular pH (extracellular acidification rate; ECAR). </span></td>
<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:76px"><span style="color:#27ae60">No </span></td>
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<p><span style="font-size:11pt"><span style="background-color:white"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="color:#2f5597">Molecular Biology:</span></span></strong><span style="font-size:12.0pt"><span style="color:#2f5597"> Nrf2. Nrf2’s transcriptional activity is controlled post-translationally by oxidation of Keap1. Assays for Nrf2 activity include: </span></span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="color:#2f5597">Method of Measurement</span></span></strong> </span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="color:#2f5597">References</span></span></strong> </span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="color:#2f5597">Description</span></span></strong> </span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><strong><span style="font-size:12.0pt"><span style="color:#2f5597">OECD-Approved Assay</span></span></strong></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Immunohistochemistry </span></span></span></span></p>
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<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:139px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Amsen, D., de Visser, K. E., and Town, T., 2009)</span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="background-color:white"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Immunohistochemistry for increases in Nrf2 protein levels and translocation into the nucleus </span></span></span></span></span></p>
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<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:75px">
<p style="text-align:center"><span style="font-size:11pt"><span style="background-color:white"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Quantitative polymerase chain reaction (qPCR) </span></span></span></span></p>
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<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:139px">
<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Forlenza et al., 2012)</span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="background-color:white"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">qPCR of Nrf2 target genes (e.g., Nqo1, Hmox-1, Gcl, Gst, Prx, TrxR, Srxn), or by commercially available pathway-based qPCR array (e.g., oxidative stress array from SABiosciences) </span></span></span></span></span></p>
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<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; vertical-align:top; width:75px">
<p style="text-align:center"><span style="font-size:11pt"><span style="background-color:white"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Whole transcriptome profiling via microarray or via RNA-seq followed by a pathway analysis</span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="background-color:white"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">(Jackson, A. F. et al., 2014)</span></span></span></span></span></p>
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<p><span style="font-size:11pt"><span style="background-color:white"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">Whole transcriptome profiling by microarray or RNA-seq followed by pathway analysis (in IPA, DAVID, metacore, etc.) for enrichment of the Nrf2 oxidative stress response pathway</span></span></span></span></span></p>
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<td style="border-bottom:1px solid black; border-left:none; border-right:1px solid black; border-top:none; height:46px; vertical-align:top; width:75px">
<p style="text-align:center"><span style="font-size:11pt"><span style="background-color:white"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="color:#2f5597">No</span></span></span></span></span></p>
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<p><span style="color:#27ae60"><strong>Taxonomic applicability: </strong>Occurrence of oxidative stress is not species specific. </span></p>
<p><span style="color:#27ae60"><strong>Life stage applicability:</strong> Occurrence of oxidative stress is not life stage specific. </span></p>
<p><span style="color:#27ae60"><strong>Sex applicability: </strong>Occurrence of oxidative stress is not sex specific. </span></p>
<p><span style="color:#27ae60"><strong>Evidence for perturbation by prototypic stressor:</strong> There is evidence of the increase of oxidative stress following perturbation from a variety of stressors including exposure to ionizing radiation and altered gravity (Bai et al., 2020; Ungvari et al., 2013; Zhang et al., 2009). </span></p>
HighMixedHighAll life stagesHighHigh<p style="margin-left:48px; text-align:left"><span style="font-size:12pt"><span style="font-family:"Times New Roman",serif"><span style="color:black">Ahmad, S. et al. (2021), “60Co-γ Radiation Alters Developmental Stages of Zeugodacus cucurbitae (Diptera: Tephritidae) Through Apoptosis Pathways Gene Expression”, <em>Journal Insect Science,</em> Vol. 21/5, Oxford University Press, Oxford, </span><a href="https://doi.org/10.1093/jisesa/ieab080" style="color:#0563c1; text-decoration:underline">https://doi.org/10.1093/jisesa/ieab080</a></span></span></p>
<p style="margin-left:48px; text-align:left"><span style="font-size:12pt"><span style="font-family:"Times New Roman",serif">Antelmann, H. and J. D. Helmann (2011), “Thiol-based redox switches and gene regulation.”, <em>Antioxidants & Redox Signaling</em>, Vol. 14/6, Mary Ann Leibert Inc., Larchmont, <a href="https://doi.org/10.1089/ars.2010.3400" style="color:#0563c1; text-decoration:underline">https://doi.org/10.1089/ars.2010.3400</a></span></span></p>
<p style="margin-left:48px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif">Amsen, D., de Visser, K. E., and Town, T. (2009), “Approaches to determine expression of inflammatory cytokines”, in <em>Inflammation and Cancer</em>, Humana Press, Totowa, </span></span><a href="https://doi.org/10.1007/978-1-59745-447-6_5" style="color:#0563c1; text-decoration:underline"><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif"><span style="color:#1155cc">https://doi.org/10.1007/978-1-59745-447-6_5</span></span></span></a> </span></span></p>
<p style="margin-left:48px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif"><span style="color:black">Azimzadeh, O. et al. (2015), “Integrative Proteomics and Targeted Transcriptomics Analyses in Cardiac Endothelial Cells Unravel Mechanisms of Long-Term Radiation-Induced Vascular Dysfunction”, <em>Journal of Proteome Research</em>, Vol. 14/2, American Chemical Society, Washington, </span></span></span><a href="https://doi.org/10.1021/pr501141b" style="color:#0563c1; text-decoration:underline"><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif">https://doi.org/10.1021/pr501141b</span></span></a></span></span></p>
<p style="margin-left:48px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif"><span style="color:black">Azimzadeh, O. et al. (2017), “Proteome analysis of irradiated endothelial cells reveals persistent alteration in protein degradation and the RhoGDI and NO signalling pathways”, <em>International Journal of Radiation Biology</em>, Vol. 93/9, Informa, London, </span></span></span><a href="https://doi.org/10.1080/09553002.2017.1339332" style="color:#0563c1; text-decoration:underline"><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif">https://doi.org/10.1080/09553002.2017.1339332</span></span></a></span></span></p>
<p style="margin-left:48px"><span style="color:#27ae60">Azzam, E. I. et al. (2012), “Ionizing radiation-induced metabolic oxidative stress and prolonged cell injury”, Cancer Letters, Vol. 327/1-2, Elsevier, Ireland, https://doi.org/10.1016/j.canlet.2011.12.012 </span></p>
<p style="margin-left:48px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif"><span style="color:black">Bai, J. et al. (2020), “Irradiation-induced senescence of bone marrow mesenchymal stem cells aggravates osteogenic differentiation dysfunction via paracrine signaling”, <em>American Journal of Physiology - Cell Physiology</em>, Vol. 318/5, American Physiological Society, Rockville, </span></span></span><a href="https://doi.org/10.1152/ajpcell.00520.2019." style="color:#0563c1; text-decoration:underline"><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif">https://doi.org/10.1152/ajpcell.00520.2019.</span></span></a></span></span></p>
<p style="margin-left:48px"><span style="font-family:Times New Roman,Times,serif">Balasubramanian, D (2000), “Ultraviolet radiation and cataract”, <em>Journal of ocular pharmacology and therapeutics</em>, Vol. 16/3, Mary Ann Liebert Inc., Larchmont, <a href="https://doi.org/10.1089/jop.2000.16.285.%22%20/t%20%22_blank" rel="noreferrer noopener" target="_blank">https://doi.org/10.1089/jop.2000.16.285.</a> </span></p>
<p style="margin-left:48px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif">Biesemann, N. et al., (2018), “High Throughput Screening of Mitochondrial Bioenergetics in Human Differentiated Myotubes Identifies Novel Enhancers of Muscle Performance in Aged Mice”, <em>Scientific Reports, </em>Vol. 8/1,</span></span> <span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif">Nature Portfolio, London, </span></span><a href="https://doi.org/10.1038/s41598-018-27614-8" style="color:#0563c1; text-decoration:underline"><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif">https://doi.org/10.1038/s41598-018-27614-8</span></span></a><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif">. </span></span></span></span></p>
<p style="margin-left:48px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif"><span style="color:black">Elgazzar, A. and N. Kazem. (2015), “Chapter 23: Biological effects of ionizing radiation” in <em>The Pathophysiologic Basis of Nuclear Medicine</em>, Springer, New York, pp. 540-548</span></span></span></span></span></p>
<p style="margin-left:48px"><span style="font-family:Times New Roman,Times,serif">Fletcher, A. E (2010), “Free radicals, antioxidants and eye diseases: evidence from epidemiological studies on cataract and age-related macular degeneration”, <em>Ophthalmic Research</em>, Vol. 44, Karger International, Basel, <a href="https://doi.org/10.1159/000316476.%22%20/t%20%22_blank" rel="noreferrer noopener" target="_blank">https://doi.org/10.1159/000316476.</a> </span></p>
<p style="margin-left:48px"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif">Forlenza, M. et al. (2012), “The use of real-time quantitative PCR for the analysis of cytokine mRNA levels” in <em>Cytokine Protocols, </em>Springer, New York, </span></span><a href="https://doi.org/10.1007/978-1-61779-439-1_2" style="color:#0563c1; text-decoration:underline"><span style="font-size:12.0pt"><span style="font-family:"Times New Roman",serif">https://doi.org/10.1007/978-1-61779-439-1_2</span></span></a><strong> </strong></span></span></p>
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2017-05-30T13:58:172024-03-08T12:28:08Memory LossMemory LossIndividual2021-10-26T03:35:512021-10-26T03:35:51Impaired axonial transportImpaired axonial transportCellular<p>The cytoskeleton plays an important role in neurons as it is required for the typical neuronal architecture of one long process, the axon, and several shorter dendrites. [1] Furthermore, the intact cytoskeleton is also of high importance as it is needed for processes like axonal transport. As axons lack the machinery to synthesize proteins, all necessary proteins have to be transported from the cell body to the periphery. Microtubules which are a basic element of the cytoskeleton play an important role in axonal transport and the maintenance of neurons. [2]<strong> </strong>They are highly dynamic and polarized structures with a stable minus end and a dynamic plus end. In axons, the plus end is directed away from the soma. [1] Microtubules serve as molecular tracks in neurons to ensure the transport of cargoes to different parts of the cell as well as the clearance of damaged cell organelles. The kinesins are microtubule-based molecular motors and are necessary for the anterograde transport of materials needed for maintenance of axons and synapses. [3, 4] Retrograde transport of degradation products from the axon/synapse back to the cell body is crucial for neuronal maintenance and survival as well. [5] Retrograde transport is carried out by dynein-motorproteins. [6]</p>
<p>- Vesicle motility assay: Axoplasm from squid giant axons is isolated and kept in axoplasm buffer. Preparations are analysed using a Zeiss Axiomat and organelle velocities are measured either in an automated process or by matching calibrated cursor movements to the speed of moving vesicles in agreement of two observers. [7-9]</p>
<p>- Kinesin-driven microtubule gliding assay: Slide chambers are covered with kinesins which adhere e.g. to specific antibodies on the glass slides. Rhodamine-labelled tubulin and unlabelled tubulin are mixed and assembled to microtubule structures. Microtubules are applied to the chamber and the rhodamine fluorescence is visualized to evaluate microtubule gliding. Microtubule-bodies are located and tracked to collect data on gliding velocity, trajectory curvature and microtubule length. [7, 10]</p>
<p>- Horseradish peroxidase (HRP) microinjection: HRP is injected into dorsal root ganglia neurons and visualized by 3,3’-diaminobenzidine. Microscope recordings of the neurons showing the transport of HRP are evaluated and the transport length is measured. [11]</p>
<p>- Mitochondrial trafficking: Cells are incubated with drug or DMSO solution and afterwards mitochondria are labelled with MitoTracker Green FM. Cells are kept in a live cell chamber and imaged in regular intervals. The time-lapse is used to track mitochondrial movement in neurites. [12]</p>
<p>- Axonal transport in mouse sciatic nerve: The drug is administered to mice intravenously. Mice are anesthetized and the left sciatic nerve is exposed and ligated at two points. After 24h, the ligated sciatic nerves are dissected and segments from proximal and distal sides of the ligation are collected, homogenized and analysed by Western blot. [12]</p>
<p>1. Baas, P.W., et al., <em>Stability properties of neuronal microtubules.</em> Cytoskeleton (Hoboken), 2016. <strong>73</strong>(9): p. 442-60.</p>
<p>2. Hirokawa, N., <em>Axonal transport and the cytoskeleton.</em> Current Opinion in Neurobiology, 1993. <strong>3</strong>(5): p. 724-731.</p>
<p>3. Leopold, P.L., et al., <em>Association of kinesin with characterized membrane-bounded organelles.</em> Cell Motility and the Cytoskeleton, 1992. <strong>23</strong>(1): p. 19-33.</p>
<p>4. Elluru, R.G., G.S. Bloom, and S.T. Brady, <em>Fast axonal transport of kinesin in the rat visual system: functionality of kinesin heavy chain isoforms.</em> Molecular Biology of the Cell, 1995. <strong>6</strong>(1): p. 21-40.</p>
<p>5. Delcroix, J.-D., et al., <em>Trafficking the NGF signal: implications for normal and degenerating neurons</em>, in <em>Progress in Brain Research</em>. 2004, Elsevier. p. 1-23.</p>
<p>6. Susalka, S.J. and K.K. Pfister, <em>Cytoplasmic dynein subunit heterogeneity: implications for axonal transport.</em> Journal of Neurocytology, 2000. <strong>29</strong>(11): p. 819-829.</p>
<p>7. LaPointe, N.E., et al., <em>Effects of eribulin, vincristine, paclitaxel and ixabepilone on fast axonal transport and kinesin-1 driven microtubule gliding: implications for chemotherapy-induced peripheral neuropathy.</em> Neurotoxicology, 2013. <strong>37</strong>: p. 231-9.</p>
<p>8. Morfini, G., et al., <em>Tau binding to microtubules does not directly affect microtubule‐based vesicle motility.</em> Journal of Neuroscience Research, 2007. <strong>85</strong>(12): p. 2620-2630.</p>
<p>9. Morfini, G., et al., <em>JNK mediates pathogenic effects of polyglutamine-expanded androgen receptor on fast axonal transport.</em> Nature Neuroscience, 2006. <strong>9</strong>: p. 907.</p>
<p>10. Peck, A., et al., <em>Tau isoform‐specific modulation of kinesin‐driven microtubule gliding rates and trajectories as determined with tau‐stabilized microtubules.</em> Cytoskeleton, 2011. <strong>68</strong>(1): p. 44-55.</p>
<p>11. Theiss, C. and K. Meller, <em>Taxol impairs anterograde axonal transport of microinjected horseradish peroxidase in dorsal root ganglia neurons in vitro.</em> Cell Tissue Res, 2000. <strong>299</strong>(2): p. 213-24.</p>
<p>12. Smith, J.A., et al., <em>Structural Basis for Induction of Peripheral Neuropathy by Microtubule-Targeting Cancer Drugs.</em> Cancer Research, 2016. <strong>76</strong>(17): p. 5115-5123.</p>
2019-01-29T08:49:262019-01-29T10:07:16Decrease of neuronal network functionNeuronal network function, DecreasedOrgan<p><strong>Biological state:</strong> There are striking differences in neuronal network formation and function among the developing and mature brain. The developing brain shows a slow maturation and a transient passage from spontaneous, long-duration action potentials to synaptically-triggered, short-duration action potentials.</p>
<p>Furthermore, at this precise developmental stage the neuronal network is characterised by "hyperexcitability”, which is related to the increased number of local circuit recurrent excitatory synapses and the lack of γ-amino-butyric acid A (GABAA)-mediated inhibitory function that appears much later. This “hyperexcitability” disappears with maturation when pairing of the pre- and postsynaptic partners occurs and synapses are formed generating population of postsynaptic potentials and population of spikes followed by developmental GABA switch. Glutamatergic neurotransmission is dominant at early stages of development and NMDA receptor-mediated synaptic currents are far more times longer than those in maturation, allowing more calcium to enter the neurons. The processes that are involved in increased calcium influx and the subsequent intracellular events seem to play a critical role in establishment of wiring of neural circuits and strengthening of synaptic connections during development (reviewed in Erecinska et al., 2004). Neurons that do not receive glutaminergic stimulation are undergoing developmental apoptosis.</p>
<p>During the neonatal period, the brain is subject to profound alterations in neuronal circuitry due to high levels of synaptogenesis and gliogenesis. For example, in neuroendocrine regions such as the preoptic area-anterior hypothalamus (POA-AH), the site of gonadotropin-releasing hormone (GnRH) system is developmentally regulated by glutamatergic neurons. The changes in the expression of the N-methyl-D-aspartate (NMDA) receptor subunits NR1 and NR2B system begin early in postnatal development, before the onset of puberty, thereby playing a role in establishing the appropriate environment for the subsequent maturation of GnRH neurons (Adams et al., 1999).</p>
<p><strong>Biological compartments:</strong> Neural network formation and function happen in all brain regions but it appears to onset at different time points of development (reviewed in Erecinska et al., 2004). Glutamatergic neurotransmission in hippocampus is poorly developed at birth. Initially, NMDA receptors play important role but the vast majority of these premature glutamatergic synapses are “silent” possibly due to delayed development of hippocampal AMPA receptors. In contrast, in the cerebral cortex the maturation of excitatory glutamatergic neurotransmission happens much earlier. The “silent” synapses disappear by PND 7-8 in both brain regions mentioned above.</p>
<p>There is strong evidence suggesting that NMDA receptor subunit composition controls synaptogenesis and synapse stabilization (Gambrill and Barria, 2011). It is established fact that during early postnatal development in the rat hippocampus, synaptogenesis occurs in parallel with a developmental switch in the subunit composition of NMDA receptors from NR2B to NR2A. It is suggested that early expression of NR2A in organotypic hippocampal slices reduces the number of synapses and the volume and dynamics of spines. In contrast, overexpression of NR2B does not affect the normal number and growth of synapses. However, it does increase spine motility, adding and retracting spines at a higher rate. The C terminus of NR2B, and specifically its ability to bind CaMKII, is sufficient to allow proper synapse formation and maturation. Conversely, the C terminus of NR2A was sufficient to stop the development of synapse number and spine growth. These results indicate that the ratio of synaptic NR2B over NR2A controls spine motility and synaptogenesis, and suggest a structural role for the intracellular C terminus of NR2 in recruiting the signalling and scaffolding molecules necessary for proper synaptogenesis. Interestingly, it was found that genetic deletion of NR3A accelerates glutamatergic synaptic transmission, as measured by AMPAR-mediated postsynaptic currents recorded in hippocampal CA1. Consistent, the deletion of NR3A accelerates the expression of the glutamate receptor subunits NR1, NR2A, and GluR1 sugesting that glutamatergic synapse maturation is critically dependent upon activation of NMDA-type glutamate receptors (Henson et al., 2012).</p>
<p><strong>General role in biology:</strong> The development of neuronal networks can be distinguished into two phases: an early ‘establishment’ phase of neuronal connections, where activity-dependent and independent mechanisms could operate, and a later ‘maintenance’ phase, which appears to be controlled by neuronal activity (Yuste and Sur, 1999). These neuronal networks facilitate information flow that is necessary to produce complex behaviors, including learning and memory (Mayford et al., 2012).</p>
<p><em>Methods that have been previously reviewed and approved by a recognized authority should be included in the Overview section above. All other methods, including those well established in the published literature, should be described here. Consider the following criteria when describing each method: 1. Is the assay fit for purpose? 2. Is the assay directly or indirectly (i.e. a surrogate) related to a key event relevant to the final adverse effect in question? 3. Is the assay repeatable? 4. Is the assay reproducible? </em></p>
<p><strong>In vivo:</strong> The recording of brain activity by using electroencephalography (EEG), electrocorticography (ECoG) and local field potentials (LFP) assists towards the collection of signals generated by multiple neuronal cell networks. Advances in computer technology have allowed quantification of the EEG and expansion of quantitative EEG (qEEG) analysis providing a sensitive tool for time-course studies of different compounds acting on neuronal networks' function (Binienda et al., 2011). The number of excitatory or inhibitory synapses can be functionally studied at an electrophysiological level by examining the contribution of glutamatergic and GABAergic synaptic inputs. The number of them can be determined by variably clamping the membrane potential and recording excitatory and inhibitory postsynaptic currents (EPSCs or IPSCs) (Liu, 2004).</p>
<p><strong>In vitro:</strong> Microelectrode array (MEA) recordings are also used to measure electrical activity in cultured neurons (Keefer et al., 2001, Gramowski et al., 2000; Gopal, 2003; Johnstone et al., 2010). MEAs can be applied in high throughput platforms to facilitate screening of numerous chemical compounds (McConnell et al., 2012). Using selective agonists and antagonists of different classes of receptors their response can be evaluated in a quantitative manner (Novellino et al., 2011; Hogberg et al., 2011).</p>
<p>Patch clamping technique can also be used to measure neuronal network activity.In some cases, if required, planar patch clamping technique can also be used to measure neuronal networks activity (e.g., Bosca et al., 2014).</p>
<p>In vitro studies in brain slices applying electrophysiological techniques showed significant variability among species (immature rats, rabbits and kittens) related to synaptic latency, duration, amplitude and efficacy in spike initiation (reviewed in Erecinska et al., 2004).</p>
UBERON:0000955brainHighMixedHighDuring brain developmentHighHighHighHigh<p>Adams MM, Flagg RA, Gore AC., Perinatal changes in hypothalamic N-methyl-D-aspartate receptors and their relationship to gonadotropin-releasing hormone neurons. Endocrinology. 1999 May;140(5):2288-96.</p>
<p>Binienda ZK, Beaudoin MA, Thorn BT, Ali SF. (2011) Analysis of electrical brain waves in neurotoxicology: γ-hydroxybutyrate. Curr Neuropharmacol. 9: 236-239.</p>
<p>Bosca, A., M. Martina, and C. Py (2014) Planar patch clamp for neuronal networks--considerations and future perspectives. Methods Mol Biol, 2014. 1183: p. 93-113.</p>
<p>Erecinska M, Cherian S, Silver IA. (2004) Energy metabolism in mammalian brain during development. Prog Neurobiol. 73: 397-445.</p>
<p>Gambrill AC, Barria A. NMDA receptor subunit composition controls synaptogenesis and synapse stabilization. Proc Natl Acad Sci U S A. 2011:108(14):5855-60.</p>
<p>Gopal K. (2003) Neurotoxic effects of mercury on auditory cortex networks growing on microelectrode arrays: a preliminary analysis. Neurotoxicol Teratol. 25: 69-76.</p>
<p>Gramowski A, Schiffmann D, Gross GW. (2000) Quantification of acute neurotoxic effects of trimethyltin using neuronal networks cultures on microelectrode arrays. Neurotoxicology 21: 331-342.</p>
<p>Henson MA, Larsen RS, Lawson SN, Pérez-Otaño I, Nakanishi N, Lipton SA, Philpot BD. (2012) Genetic deletion of NR3A accelerates glutamatergic synapse maturation. PLoS One. 7(8).</p>
<p>Hogberg HT, Sobanski T, Novellino A, Whelan M, Weiss DG, Bal-Price AK. (2011) Application of micro-electrode arrays (MEAs) as an emerging technology for developmental neurotoxicity: evaluation of domoic acid-induced effects in primary cultures of rat cortical neurons. Neurotoxicology 32: 158-168.</p>
<p>Johnstone AFM, Gross GW, Weiss D, Schroeder O, Shafer TJ. (2010) Use of microelectrode arrays for neurotoxicity testing in the 21st century Neurotoxicology 31: 331-350.</p>
<p>Keefer E, Norton S, Boyle N, Talesa V, Gross G. (2001) Acute toxicity screening of novel AChE inhibitors using neuronal networks on microelectrode arrays. Neurotoxicology 22: 3-12.</p>
<p>Liu G. (2004) Local structural balance and functional interaction of excitatory and inhibitory synapses in hippocampal dendrites. Nat Neurosci. 7: 373-379.</p>
<p>Mayford M, Siegelbaum SA, Kandel ER. (2012) Synapses and memory storage. Cold Spring Harb Perspect Biol. 4. pii: a005751.</p>
<p>McConnell ER, McClain MA, Ross J, LeFew WR, Shafer TJ. (2012) Evaluation of multi-well microelectrode arrays for neurotoxicity screening using a chemical training set. Neurotoxicology 33: 1048-1057.</p>
<p>Novellino A, Scelfo B, Palosaari T, Price A, Sobanski T, Shafer TJ, Johnstone AF, Gross GW, Gramowski A, Schroeder O, Jügelt K, Chiappalone M, Benfenati F, Martinoia S, Tedesco MT, Defranchi E, D'Angelo P, Whelan M. (2011) Development of micro-electrode array based tests for neurotoxicity: assessment of interlaboratory reproducibility with neuroactive chemicals. Front Neuroeng. 4: 4.</p>
<p>Yuste R, Peinado A, Katz LC. (1992) Neuronal domains in developing neocortex. Science 257: 665-669.</p>
2016-11-29T18:41:242018-05-28T11:36:00NeuroinflammationNeuroinflammationTissue<p>Neuroinflammation or brain inflammation differs from peripheral inflammation in that the vascular response and the role of peripheral bone marrow-derived cells are less conspicuous. The most easily detectable feature of neuroinflammation is activation of microglial cells and astrocytes. It is evidenced by changes in shape, increased expression of certain antigens, and accumulation and proliferation of the glial cells in affected regions (Aschner, 1998; Graeber & Streit, 1990; Monnet-Tschudi et al, 2007; Streit et al, 1999; Kraft and Harry, 2011; Claycomb et al., 2013). Upon stimulation by cytokines or inflammogens (e.g. from pathogens or from damaged neurons), both glial cell types activate inflammatory signalling pathways, which result in increased expression and/or release of inflammatory mediators such as cytokines, eicosanoids, and metalloproteinases (Dong & Benveniste, 2001), as well as in the production of reactive oxygen (ROS) and nitrogen species (RNS) (Brown & Bal-Price, 2003). Different types of activation states are possible for microglia and astrocytes, resulting in pro-inflammatory or anti-inflammatory signalling and other cellular functions (such as phagocytosis) (Streit et al., 1999; Nakajima and Kohsaka, 2004).</p>
<p>Therefore, neuroinflammation can have both neuroprotective/neuroreparative and neurodegenerative consequences (Carson et al., 2006 ; Monnet-Tschudi et al, 2007; Aguzzi et al., 2013 ; Glass et al., 2010). Under normal physiological conditions, microglial cells scan the nervous system for neuronal integrity (Nimmerjahn et al, 2005) and for invading pathogens (Aloisi, 2001; Kreutzberg, 1995; Kreutzberg, 1996; Rivest, 2009). They are the first type of cell activated (first line of defence), and can subsequently induce astrocyte activation (Falsig, 2008). Two distinct states of microglial activation have been described (Gordon, 2003; Kigerl et al, 2009; Maresz et al, 2008; Mosser & Edwards, 2008; Perego et al; Ponomarev et al, 2005; Moehle and West, 2015): The M1 state is classically triggered by interferon-gamma and/or other pro-inflammatory cytokines, and this state is characterized by increased expression of integrin alpha M (Itgam) and CD86, as well as the release of pro-inflammatory cytokines (TNF-alpha, IL-1beta, IL-6), and it is mostly associated with neurodegeneration. The M2 state is triggered by IL-4 and IL-13 (Maresz et al, 2008; Perego et al, 2011; Ponomarev et al, 2007) and induces the expression of mannose receptor 1 (MRC1), arginase1 (Arg 1) and Ym1/2; it is involved in repair processes. The activation of astrocytes by microglia-derived cytokines or TLR agonists resembles the microglial M1 state (Falsig 2006). Although classification of the M1/M2 polarization of microglial cells may be considered as a simplification of authentic microglial reaction states (Ransohoff, 2016), a similar polarization of reactive astrocytes has been descibed recently Liddlelow et al., 2017): Interleukin-1 alpha (IL-1alpha), TNF and subcomponent q (C1q) released by activated microglial cells induce A1-reactive astrocytes, which lose the ability to promote neuronal survival, outgrowth, synaptogenesis and phagocytosis and induce the death of neurons and oligodendrocytes.</p>
<p> </p>
<p><strong>Neuroinflammation and Brain development</strong></p>
<p>During brain development, microglia are known to play a critical role as shapers of neural circuits, by providing trophic factors and by remodeling and pruning synapses (Rajendran and Paolicelli, 2018). In addition to playing a role in synaptic management, microglia are important for the pruning of dying neurons and in the clearance of debris (<a href="#_ENREF_43" title="Harry, 2013 #5042">Harry, 2013</a>). Microglia seem to affect also processes associated with neuronal proliferation and differentiation (Harry and Kraft, 2012). Similarly to microglia, astrocytes have instructive roles in neurogenesis, gliogenesis, angiogenesis, axonal outgrowth, synaptogenesis, and synaptic pruning (Reemst et al., 2016).</p>
<p>The development-dependent reactivity of microglial cells and astrocytes is not well known. Ischemic insult appears to elicit similar microglial reactivity both during brain development and in adulthood (<a href="#_ENREF_3" title="Baburamani, 2014 #6737">Baburamani et al, 2014</a>; <a href="#_ENREF_54" title="Leonardo, 2009 #6879">Leonardo & Pennypacker, 2009</a>). In contrast, treatment with lead acetate was previously shown to result in a more pronounced microglial and astrocyte reactivity in immature 3D rat brain cell cultures as compared to mature ones (<a href="#_ENREF_101" title="Zurich, 2002 #3368">Zurich et al, 2002</a>). Astrocyte reactivity was also more pronounced in immature 3D rat brain cell cultures following paraquat exposure, whereas development-dependent differences in the phenotype of reactive microglia were observed (Sandström et al., 2017). This suggests that neuroinflammation is occurring during brain development and may express a different phenotype than in adulthood, and that dysfunction of microglia and astrocyte during brain development could contribute to neurodevelopmental disorders and potentially to late-onset neuropathology (Reemst et al., 2016).</p>
<p> </p>
<p><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif"><strong>Neuroinflammation in relation to COVID19</strong></span></span></p>
<p><span style="font-size:16px"><span style="font-family:Arial,Helvetica,sans-serif">SARS-CoV-2 patients with moderate and severe COVID-19 presented an elevated plasma levels of glial fibrillary acidic protein (GFAP), which is known as biochemical indicator of glial activation (Kanberg et al., 2020).</span></span></p>
<p>Neuroinflammation, i.e. the activation of glial cells can be measured by quantification of cellular markers (most commonly), or of released mediators (less common). As multiple activation states exist for the two main cell types involved, it is necessary to measure several markers of neuroinflammation:</p>
<ul>
<li>Microglial activation can be detected based on the increased numbers of labeled microglia per volume element of brain tissue (due to increase of binding sites, proliferation, and immigration of cells) or on morphological changes. A specific microglial marker, used across different species, is CD11b. Alternatively various specific carbohydrate structures can be stained by lectins (e.g. IB4). Beyond that, various well-established antibodies are available to detect microglia in mouse tissue (F4/80), phagocytic microglia in rat tissue (ED1) or more generally microglia across species (Iba1). Transgenic mice are available with fluorescent proteins under the control of the CD11b promoter to easily quantify microglia without the need for specific stains.</li>
<li>The most frequently used astrocyte marker is GFAP (99% of all studies) (Eng et al., 2000). This protein is highly specific for astrocytes in the brain, and antibodies are available for immunocytochemical detection. In neuroinflammatory brain regions, the stain becomes more prominent, due to an upregulation of the protein, a shape change/proliferation of the cells, and/or better accessibility of the antibody. Various histological quantification approaches can be used. Occasionally, alternative astrocytic markers, such as vimentin of the S100beta protein, have been used for staining of astrocytes (Struzynska et al., 2007). Antibodies for complement component 3 (C3), the most characteristic and highly upregulated marker of A1 neurotoxic reactive astrocytes are commercially available.</li>
<li>All immunocytochemical methods can also be applied to cell culture models.</li>
<li>In patients, microglial accumulation can be monitored by PET imaging, using [11C]-PK 11195 as a microglial marker (Banati et al., 2002).</li>
<li>Activation of glial cells can be assessed in tissue or cell culture models also by quantification of sets of activation markers. This can for instance be done by PCR quantification of inflammatory factors, by measurement of the respective mediators, e.g. by ELISA-related immuno-quantification. Such markers include:</li>
<li>Pro- and anti-inflammatory cytokine expression (IL-1β; TNF-α, Il-6, IL-4); or expression of immunostimmulatory proteins (e.g. MHC-II)</li>
<li>Itgam, CD86 expression as markers of M1 microglial phenotype</li>
<li>Arg1, MRC1, as markers of M2 microglial phenotype</li>
</ul>
<p>For descriptions of techniques, see Falsig 2004; Lund 2006 ; Kuegler 2010; Monnet-Tschudi et al., 2011; Sandström et al., 2014; von Tobel et al., 2014</p>
<p> </p>
<p><strong>Regulatory example using the KE</strong></p>
<p>Measurement of glial fibrillary acidic protein (GFAP) in brain tissue, whose increase is a marker of astrocyte reactivity, is required by the US EPA in rodent toxicity studies for fuel additives (40 CFR 79.67). It has been used on rare occasions for other toxicant evaluations.</p>
<p>Neuroinflammation is observed in human, monkey, rat, mouse, and zebrafish, in association with neurodegeneration or following toxicant exposure, <span style="font-family:Arial,Helvetica,sans-serif"><span style="font-size:16px">or SARS-CoV-2 and other coronavirus infection. </span>Some references (non-exhaustive list) are given below for illustration:</span></p>
<p><span style="font-family:Arial,Helvetica,sans-serif">Human: Vennetti et al., 2006</span></p>
<p>Monkey (Macaca fascicularis): Charleston et al., 1994, 1996</p>
<p>Rat: Little et al., 2012; Zurich et al., 2002; Eskes et al., 2002</p>
<p>Mouse: Liu et al., 2012</p>
<p>Zebrafish: Xu et al., 2014.</p>
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<p><span style="font-size:12px">Aloisi, F., 2001. Immune function of microglia. Glia 36, 165-179.</span></p>
<p><span style="font-size:12px">Aschner M (1998) Immune and inflammatory responses in the CNS: modulation by astrocytes. ToxicolLett 103: 283-287</span></p>
<p><span style="font-size:12px">Banati, R. B. (2002). "Visualising microglial activation <em>in vivo</em>." Glia 40: 206-217. </span></p>
<p><span style="font-size:12px">Baburamani AA, Supramaniam VG, Hagberg H, Mallard C (2014) Microglia toxicity in preterm brain injury. <em>Reprod Toxicol</em> <strong>48:</strong> 106-112</span></p>
<p><span style="font-size:12px">Brown GC, Bal-Price A (2003) Inflammatory neurodegeneration mediated by nitric oxide, glutamate, and mitochondria. Mol Neurobiol 27: 325-355</span></p>
<p><span style="font-size:12px">Carson, M.J., Thrash, J.C., Walter, B., 2006. The cellular response in neuroinflammation: The role of leukocytes, microglia and astrocytes in neuronal death and survival. Clin Neurosci Res 6(5), 237-245.</span></p>
<p><span style="font-size:12px">Charleston JS, Body RL, Bolender RP, Mottet NK, Vahter ME, Burbacher TM. 1996. Changes in the number of astrocytes and microglia in the thalamus of the monkey Macaca fascicularis following long-term subclinical methylmercury exposure. NeuroToxicology 17: 127-138.</span></p>
<p><span style="font-size:12px">Charleston JS, Bolender RP, Mottet NK, Body RL, Vahter ME, Burbacher TM. 1994. Increases in the number of reactive glia in the visual cortex of Macaca fascicularis following subclinical long-term methyl mercury exposure. ToxicolApplPharmacol 129: 196-206.</span></p>
<p><span style="font-size:12px">Claycomb, K.I., Johnson, K.M., Winokur, P.N., Sacino, A.V., Crocker, S.J., 2013. Astrocyte regulation of CNS inflammation and remyelination. Brain Sci 3(3), 1109-1127.</span></p>
<p><span style="font-size:12px">Dong Y, Benveniste EN (2001) Immune Function of Astrocytes. Glia 36: 180-190</span></p>
<p><span style="font-size:12px">Eng LF, Ghirnikar RS, Lee YL (2000) Glial Fibrillary Acidic Protein: GFAP-Thirty-One Years (1969-2000). NeurochemRes 25: 1439-1451</span></p>
<p><span style="font-size:12px">Eskes C, Honegger P, Juillerat-Jeanneret L, Monnet-Tschudi F. 2002. Microglial reaction induced by noncytotoxic methylmercury treatment leads to neuroprotection via interactions with astrocytes and IL-6 release. Glia 37(1): 43-52.</span></p>
<p><span style="font-size:12px">Falsig J, Latta M, Leist M. Defined inflammatory states in astrocyte cultures correlation with susceptibility towards CD95-driven apoptosis. J Neurochem. 2004 Jan;88(1):181-93.</span></p>
<p><span style="font-size:12px">Falsig J, Pörzgen P, Lund S, Schrattenholz A, Leist M. The inflammatory transcriptome of reactive murine astrocytes and implications for their innate immune function. J Neurochem. 2006 Feb;96(3):893-907.</span></p>
<p><span style="font-size:12px">Falsig J, van Beek J, Hermann C, Leist M. Molecular basis for detection of invading pathogens in the brain. J Neurosci Res. 2008 May 15;86(7):1434-47.</span></p>
<p><span style="font-size:12px">Glass CK, Saijo K, Winner B, Marchetto MC, Gage FH (2010). Mechanisms underlying inflammation in neurodegeneration. Cell. 2010 Mar 19;140(6):918-34.</span></p>
<p><span style="font-size:12px">Gordon S (2003) Alternative activation of macrophages. Nat Rev Immunol 3: 23-35</span></p>
<p><span style="font-size:12px">Graeber MB, Streit WJ (1990) Microglia: immune network in the CNS. Brain Pathol 1: 2-5</span></p>
<p><span style="font-size:12px">Harry GJ and Kraft AD (2012) Microglia in the developing brain: apotential target with lifetime effects. <a href="https://www.ncbi.nlm.nih.gov/pubmed/22322212" title="Neurotoxicology.">Neurotoxicology.</a> 33(2):191-206.</span></p>
<p><span style="font-size:12px">Harry GJ (2013) Microglia during development and aging. <em>Pharmacology & therapeutics</em> <strong>139:</strong> 313-326</span></p>
<p><span style="font-size:12px">Kanberg N, et al. Neurochemical evidence of astrocytic and neuronal injury commonly found in COVID-19. Neurology. 2020 Sep 22;95(12):e1754-e1759</span></p>
<p><span style="font-size:12px">Kigerl KA, Gensel JC, Ankeny DP, Alexander JK, Donnelly DJ, Popovich PG (2009) Identification of two distinct macrophage subsets with divergent effects causing either neurotoxicity or regeneration in the injured mouse spinal cord. J Neurosci 29: 13435-13444</span></p>
<p><span style="font-size:12px">Kraft AD, Harry GJ., Features of microglia and neuroinflammation relevant to environmental exposure and neurotoxicity. International Journal of Environmental research and Public Health., 2011, 8(7): 2980-3018.</span></p>
<p><span style="font-size:12px">Kreutzberg GW (1995) Microglia, the first line of defence in brain pathologies. Arzneimttelforsch 45: 357-360</span></p>
<p><span style="font-size:12px">Kreutzberg GW (1996) Microglia : a sensor for pathological events in the CNS. Trends Neurosci 19: 312-318</span></p>
<p><span style="font-size:12px">Kuegler PB, Zimmer B, Waldmann T, Baudis B, Ilmjärv S, Hescheler J, Gaughwin P, Brundin P, Mundy W, Bal-Price AK, Schrattenholz A, Krause KH, van Thriel C, Rao MS, Kadereit S, Leist M. Markers of murine embryonic and neural stem cells, neurons and astrocytes: reference points for developmental neurotoxicity testing. ALTEX. 2010;27(1):17-42</span></p>
<p><span style="font-size:12px">Leonardo CC, Pennypacker KR (2009) Neuroinflammation and MMPs: potential therapeutic targets in neonatal hypoxic-ischemic injury. <em>J Neuroinflammation</em> <strong>6:</strong> 13</span></p>
<p><span style="font-size:12px">Liddelow SA, Guttenplan KA, Clarke LE, Bennett FC, Bohlen CJ, Schirmer L, et al. 2017. Neurotoxic reactive astrocytes are induced by activated microglia. Nature 541(7638): 481-487.</span></p>
<p><span style="font-size:12px">Little AR, Miller DB, Li S, Kashon ML, O'Callaghan JP. 2012. Trimethyltin-induced neurotoxicity: gene expression pathway analysis, q-RT-PCR and immunoblotting reveal early effects associated with hippocampal damage and gliosis. Neurotoxicol Teratol 34(1): 72-82.</span></p>
<p><span style="font-size:12px">Liu Y, Hu J, Wu J, Zhu C, Hui Y, Han Y, et al. 2012. alpha7 nicotinic acetylcholine receptor-mediated neuroprotection against dopaminergic neuron loss in an MPTP mouse model via inhibition of astrocyte activation. J Neuroinflammation 9: 98.</span></p>
<p><span style="font-size:12px">Lund S, Christensen KV, Hedtjärn M, Mortensen AL, Hagberg H, Falsig J, Hasseldam H, Schrattenholz A, Pörzgen P, Leist M. The dynamics of the LPS triggered inflammatory response of murine microglia under different culture and <em>in vivo</em> conditions. J Neuroimmunol. 2006 Nov;180(1-2):71-87.</span></p>
<p><span style="font-size:12px">Maresz K, Ponomarev ED, Barteneva N, Tan Y, Mann MK, Dittel BN (2008) IL-13 induces the expression of the alternative activation marker Ym1 in a subset of testicular macrophages. J Reprod Immunol 78: 140-148</span></p>
<p><span style="font-size:12px">Moehle MS, West AB (2015) M1 and M2 immune activation in Parkinson's Disease: Foe and ally? Neuroscience 302:59-73 doi:10.1016/j.neuroscience.2014.11.018</span></p>
<p><span style="font-size:12px">Monnet-Tschudi F, Zurich MG, Honegger P (2007) Neurotoxicant-induced inflammatory response in three-dimensional brain cell cultures. Hum Exp Toxicol 26: 339-346</span></p>
<p><span style="font-size:12px">Monnet-Tschudi, F., A. Defaux, et al. (2011). "Methods to assess neuroinflammation." Curr Protoc Toxicol Chapter 12: Unit12 19. </span></p>
<p><span style="font-size:12px">Mosser DM, Edwards JP (2008) Exploring the full spectrum of macrophage activation. Nat Rev Immunol 8: 958-969</span></p>
<p><span style="font-size:12px">Nakajima K, Kohsaka S. 2004. Microglia: Neuroprotective and neurotrophic cells in the central nervous system. Current Drug Targets-Cardiovasc & Haematol Disorders 4: 65-84.</span></p>
<p><span style="font-size:12px">Perego C, Fumagalli S, De Simoni MG (2011) Temporal pattern of expression and colocalization of microglia/macrophage phenotype markers following brain ischemic injury in mice. J Neuroinflammation 8: 174</span></p>
<p><span style="font-size:12px">Ponomarev ED, Maresz K, Tan Y, Dittel BN (2007) CNS-derived interleukin-4 is essential for the regulation of autoimmune inflammation and induces a state of alternative activation in microglial cells. J Neurosci 27: 10714-10721</span></p>
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2016-11-29T18:41:232022-07-15T09:54:27Accumulation, Cytosolic toxic Tau oligomersAccumulation, Toxic Tau oligomersCellular2021-10-26T06:53:542021-10-26T06:53:54Hyperphosphorylation of Taup-TauCellular2021-10-26T06:57:202021-10-26T06:57:20Dysfunctional AutophagyDysfunctional autophagyCellular2021-10-26T06:59:552021-10-26T06:59:55Synaptic dysfunctionDysfunctional synapsesOrgan2021-10-26T06:58:462023-01-04T18:47:00abac18a1-48df-463f-a48e-1712bff99a17013e07c6-aeaa-4415-8e33-54753c9fe4882021-10-26T03:50:242021-10-26T03:50:24013e07c6-aeaa-4415-8e33-54753c9fe4880254ead6-bd74-4b40-adeb-745aed902fb52021-10-26T07:08:492021-10-26T07:08:49399ed03e-4ef7-433c-93b4-95c3f77813e898696255-47a2-4785-8c23-cffb2307fb022021-10-26T07:03:162021-10-26T07:03:1698696255-47a2-4785-8c23-cffb2307fb023c1fb089-ada3-4e0a-9e19-8ecb192c1eba2021-10-26T07:04:582021-10-26T07:04:583c1fb089-ada3-4e0a-9e19-8ecb192c1eba2c4db471-b19c-4cbc-a5fe-53b4fccf43ea2021-10-26T07:11:012021-10-26T07:11:012c4db471-b19c-4cbc-a5fe-53b4fccf43ea6342b164-582b-4ffc-b743-2848f9d1dea92021-10-26T07:06:022021-10-26T07:06:0298696255-47a2-4785-8c23-cffb2307fb02f8eddb22-3f2b-49fe-b68f-6e6abe7fb4102021-10-26T07:12:082021-10-26T07:12:08f8eddb22-3f2b-49fe-b68f-6e6abe7fb4106342b164-582b-4ffc-b743-2848f9d1dea92021-10-26T03:50:512021-10-26T03:50:516342b164-582b-4ffc-b743-2848f9d1dea98acd85ac-7e18-4282-9122-c6641e7b51c62021-10-26T04:51:482021-10-26T04:51:48A cholesterol/glucose dysmetabolism initiated Tau-driven AOP toward memory loss (AO) in sporadic Alzheimer's Disease with plausible MIE's plug-ins for environmental neurotoxicantstau-AOP<p>Erwin L Roggen, CEO ToxGenSolutions BV</p>
<p>Maria Tsamou, Senior Scientist, ToxGenSolutions BV</p>
Under development: Not open for comment. Do not cite<p>The worldwide prevalence of sporadic (late-onset) Alzheimer’s disease (sAD) is dramatically increasing. Aging and genetics are important risk factors, but systemic and environmental factors contribute to this risk in a still poorly understood way. Within the frame of BioMed21, the Adverse Outcome Pathway (AOP) concept for toxicology was recommended as a tool for enhancing human disease research and accelerating translation of data into human applications. Its potential to capture biological knowledge and to increase mechanistic understanding about human diseases has been substantiated since. In pursuit of the tau-cascade hypothesis, a tau-driven AOP blueprint toward the adverse outcome of memory loss is proposed. Sequences of key events and plausible key event relationships, triggered by the bidirectional relationship between brain cholesterol and glucose dysmetabolism, and contributing to memory loss are captured. To portray how environmental factors may contribute to sAD progression, information on chemicals and drugs, that experimentally or epidemiologically associate with the risk of AD and mechanistically link to sAD progression, are mapped on this AOP. The evidence suggests that chemicals may accelerate disease progression by plugging into sAD relevant processes. The proposed AOP is a simplified framework of key events and plausible key event relationships representing one specific aspect of sAD pathology, and an attempt to portray chemical interference. Other sAD-related AOPs (e.g., A-beta-driven AOP) and a better understanding of the impact of aging and genetic polymorphism are needed to further expand our mechanistic understanding of early AD pathology and the potential impact of environmental and systemic risk factors.</p>
adjacentNot SpecifiedModerateadjacentNot SpecifiedHighadjacentNot SpecifiedModerateadjacentNot SpecifiedModerateadjacentNot SpecifiedModerateadjacentNot SpecifiedHighadjacentNot SpecifiedHighadjacentNot SpecifiedHighadjacentNot SpecifiedModerateHighMixedHighHigh<p>Homo sapiens</p>
<p style="text-align:justify"><strong><u>KER4:</u> Mitochondrial dysfunction (KE1) - Oxidative stress (KE2)</strong></p>
<p style="text-align:justify"><em>The biological plausibility:</em> Pathological ROS levels result in oxidation and loss of function of proteins, lipids, and nucleic acids. The resulting oxidative stress directly, or via mitochondrial dysfunction, results in less mitochondrial biomass, intracellular ATP and respiratory complexes, elevated concentration of intracellular Ca<sup>2+</sup> and activated Ca<sup>2+</sup>-dependent calpains, cellular dysfunction and eventually cell death [70, 136-138].</p>
<p style="text-align:justify"><em>The empirical support:</em> Oxidative imbalance is predominant in AD pathogenesis [139, 140]. Accumulated 8-oxoguanine (8-oxoG), oxidized guanine, a marker for nuclear and mitochondrial DNA damage, has been found in postmortem AD hippocampus [141, 142]. Enhanced lipid peroxidation, oxidized protein and nucleic acids, and a significant decrease in antioxidant enzyme activity are reported in AD [131, 136, 143]. Proteomic analysis shows a 2-fold increase in mitochondrial protein nitration and oxidation in subjects with MCI when compared to healthy subjects, but not in AD subjects, suggesting that mitochondrial dysfunction occurs during early development of disease [144]. Several studies report that neuronal stress increases cytosolic Ca<sup>2+</sup>-activated calpain expression leading to neuropathological diseases, such as AD [145-147].</p>
<p style="text-align:justify"><em>Overall assessment: </em>Data suggest that GSH depletion and mitochondrial dysfunction are plausible causes for excessive ROS levels, but lack quantitative data about threshold, magnitude, and duration. KER4 describes the link between the upstream event ‘mitochondrial dysfunction’ and the downstream event ‘oxidative stress’. Both events are considered adjacent, despite the evidence for this relation is classified as moderate due to some inconsistencies.</p>
<p style="text-align:justify"><strong><u>KER5:</u> Oxidative Stress (KE2) - p-tau (KE3)</strong></p>
<p style="text-align:justify"><em>The biological plausibility: </em>The evidence suggest that ROS induced oxidative stress promotes pathological tau modifications and disruption of the mechanisms involved in proper mitochondrialfunctionality [139, 150-152]. Hyperphosphorylation of tau disrupts its affinity for microtubules, increases its resistance to degradation, and induces conformational changes promoting aggregation [49]. Hence, a proper regulation between tau protein phosphorylation and dephosphorylation of the many phosphorylation sites of tau is detrimental for a healthy neuronal cell physiology [153-155]. Under excessive oxidative stress Ca<sup>2+</sup>-dependent calpains activate cyclin-dependent kinase 5 (Cdk5) and GSK3β, both involved in tau hyperphosphorylation and shown to be important for proper neural development, synaptic signaling, learning and memory [155, 156]. Cdk5 and GSK3β interact with the truncated regulatory unit of p35 (p25), also a product of calpain activation [157]. Cdk5/p25 and GSK3β/p25 mediated tau phosphorylation decreases the affinity of tau for microtubules, disrupts the cytoskeleton and causes apoptosis [158, 159]. The GSK3β/p25 complex inhibits PP2A phosphorylation through increased inhibitory Tyr307 phosphorylation and decreases expression of PP2A [160]. The data suggest a GSK3β-Cdk5-PP2A synergy in tauopathy, which is characterized by decreased affinity of tau for microtubules, abnormal hyperphosphorylation, aggregation and eventually synaptic dysfunction [161-164]. </p>
<p style="text-align:justify"><em>The empirical support:</em> Mitochondrial dysfunction (KE1) and/or oxidative stress (KE2) activate the calpain signaling pathway, a process that precedes p-tau formation during the early stages of AD development [165]. Available evidence suggests that oxidative stress through tau hyperphosphorylation contributes to tau pathology and AD [166]. Calpain mediated activation of the tau kinases Cdk5 and GSK3β correlates with the degree of pathology (Braak stage II-III) and precedes tau phosphorylation and synaptic loss [165]. Proteomic analysis suggests that loss of function of neuronal peptidyl prolyl cis-trans isomerase 1 (Pin1) by oxidative damage, and its downregulation in AD hippocampus, are linked to tau phosphorylation and AD neurofibrillary pathology [167]. The observation that human truncated tau protein expression leads to accumulation of ROS and cortical neuron death in rats, suggests that tau modification may also precede oxidative stress [168].</p>
<p style="text-align:justify"><em>Overall assessment:</em> Data support that excessive ROS levels are a plausible cause for tau pathology, and that both events are adjacent. Even though it technologically is possible to measure ROS levels <em>in vitro</em>, it was not possible to find threshold and magnitude values, nor duration of exposure, that are required to result in a persistent adverse impact on p-tau levels.</p>
<p style="text-align:justify"><strong><u>KER7:</u> Dysfunctional autophagy (KE4) - cytosolic toxic tau (KE5)</strong></p>
<p style="text-align:justify"><em>The biological plausibility:</em> Progressive dysfunction of neuronal autophagic capacity contributes to the formation of an initiating substrate complex needed for the initial seeding (or nucleation) of tau (and Aβ) aggregation. As a result, cytosolic tau oligomers are formed, followed by UPS-mediated autocatalytic propagation of tau aggregation [33]. At synaptic sites, accumulated tau oligomers are correlated with accumulated ubiquitinated proteins, proteasomes and related chaperones [200]. </p>
<p style="text-align:justify"><em>The empirical support:</em> Cytosolic toxic tau oligomers are observed at very early stages of the AD [173], with human AD brain containing more tau oligomers than control samples [201]. Inhibition of autophagy in a neuroblastoma cell model of tauopathy results in elevated levels of soluble and insoluble forms of tau [199]. Observations of internalized tau aggregates colocalizing with lysosomal markers suggest a plausible role of autophagy in tau degradation or lack thereof when dysfunctional. Supporting evidence is provided by a study showing that intracellular tau seed-induced aggregate formation is inhibited by activation of autophagy with rapamycin [202]. </p>
<p style="text-align:justify"><em>Overall assessment: </em>It is plausible that a decreasing capacity to exhibit effective autophagy (KE4), in an environment of elevated p-tau (KE3), plays an important role in the accumulation of cytosolic pathologic tau variants (KE5). While the data indicate that defective autophagy, elevated p-tau and cytosolic tau levels are adjacent, there were no quantitative data found concerning threshold, magnitude or duration required to observe an adverse effect driving the development of memory loss.</p>
<p style="text-align:justify"><strong><u>KER8:</u> Cytosolic toxic tau (KE5) - dysfunctional axonal transport (KE6), <u>KER9:</u> dysfunctional axonal transport (KE6) - dysfunctional synapses (KE7), <u>KER10:</u> dysfunctional synapses (KE7) - neuronal dysfunction (KE9)</strong></p>
<p style="text-align:justify"><em>The biological plausibility: </em>Tau protein drives cognitive impairment by the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptor pathways [203]. In the neuronal dendrites, p-tau targets Fyn kinase, a substrate for the NMDA receptor at postsynaptic compartments [204, 205]. This results in delocalization of tau from axon to synapses and somatodendritic compartments, which causes NFT formation and eventually synaptic dysfunction [153, 171]. Soluble tau oligomers exert more acute toxicity than the insoluble ones [206]. Especially dimers are effectively self-associating into large oligomeric tau nuclei of aggregation. These pathological tau aggregates are cytosolic, but also appear in the extracellular space, and correlate with synaptic dysfunction, neuronal toxicity, and degeneration [206, 207]. In human induced pluripotent stem cells (iPSC)-derived neurons, induction of tau oligomers, but not monomers, drives pathological p-tau aggregation and causes neurite retraction, synaptic loss, neurotransmitters imbalance and neuronal cell death [202]. In mice, subcortical injection of oligomers reduces the expression of synaptic vesicle-associated proteins leading to synaptic dysfunction. Pathogenic tau oligomers also negatively affect mitochondria, suggesting an amplifying circle of toxic Ca<sup>2+</sup>-mediated events linking KE3 and KE5, and leading to mitochondrial dysfunction and synaptic loss [208, 209]. Tau-induced mitochondrial dysfunction (KE1) is characterized by a decrease in mitochondrial complex I levels, activation of caspase-9 and the apoptotic mitochondrial pathway [208]. Toxic Tau35 may be implicated in intraneuronal insulin accumulation and impaired insulin signaling through interactions with phosphatase and tensin homolog protein (PTEN), which inhibits dephosphorylation of PIP3 to PIP2 [210, 211].</p>
<p style="text-align:justify"><em>The empirical support: </em>Synaptic loss is associated with early cognitive decline in the neocortex and limbic system, with reductions in synaptic density at preclinical and terminal stage in AD pathology of 25% and 55%, respectively [212, 213]. The levels of markers for presynaptic terminals, synaptic vesicle and synaptic protein are reduced in early stage of AD [214]. Along the same line, a tau transgenic mouse was found to exhibit a decreased expression of synaptic proteins, such as synaptophysin, synapsin, synaptojanin, and synaptobrevin [203]. An acute exposure to extracellular human tau oligomers caused memory impairment in mice [215] probably through inhibition of IRS1 and PTEN activities and subsequent insulin resistance. Abnormal inhibitory serine phosphorylation of IRS1 by INSR has been linked to brain insulin resistance in tauopathy, including AD pathology [211].</p>
<p style="text-align:justify"><em>Overall assessment: </em>The evidence supports enhanced cytosolic toxic tau levels (KE5) being adjacent to dysfunctional axonal transport (KE6) which results subsequently in synaptic (KE7) and neural (KE9) dysfunction. Thresholds values, degree, and duration of dysfunction of these KEs required to drive this series KEs towards memory loss are not known.</p>
<p style="text-align:justify"><strong><u>KER11:</u> Toxic tau oligomers (KE5) - Neuroinflammation (KE8), <u>KER12:</u> Neuroinflammation (KE8) - Neuronal dysfunction (KE9)</strong></p>
<p style="text-align:justify"><em>The biological plausibility: </em>Small soluble tau oligomers cause inflammatory signalling in the brain by activating microglia. These inflammatory responses are mediated by activated inflammasome and promote proinflammatory interleukin 1β (IL-1β) release, which is controlled by activation of caspase-1[217]. Activation of microglia and astroglia, and subsequent release of proinflammatory cytokines occur in the brain of humans and mice exposed to p-tau [218, 219]. Colocalization of activated microglia and astroglia, and proinflammatory cytokines with tau oligomers has been observed in mouse brain, suggesting that tau oligomers play a role in neuroinflammation and in accelerating neuronal dysfunction and neurodegeneration [220]. Tau oligomer levels correlate with High Mobility Group Box 1 (HMGB1) levels, an important pro-inflammatory marker in the brain [220], with recruitment of brain T-cells being linked to tau pathology and neuroinflammatory processes [221, 222].</p>
<p style="text-align:justify"><em>The empirical support: </em>Neuroinflammatory response in AD brain is driven by potent inflammatory mediators [223] and free radicals [224]. In a cross-sectional study of elderly adults with normal cognition and impaired cognition, six CSF neuroinflammatory markers (interleukin 15 (IL-15), monocyte chemoattractant protein-1 (MCP-1), vascular endothelial growth factor receptor 1 (VEGFR-1), soluble intercellular adhesion molecule-1 (sICAM1), soluble vascular cell adhesion molecule-1 (sVCAM-1), and vascular endothelial growth factor-D (VEGF-D)) correlated with tau levels in CSF, while none correlated with Aβ levels in CSF [225]. </p>
<p style="text-align:justify"><em>Overall assessment: </em>There is strong evidence that processes resulting in increased cytosolic toxic tau levels (KE5) are adjacent to neuroinflammation (KE8), a condition that is widely accepted to play an important role in memory loss (AO) and neurodegeneration. The levels of cytotoxic tau, nor the duration of exposure, required to obtain a detectable inflammatory response sufficient to drive neuronal dysfunction are not known.</p>
<p style="text-align:justify"><strong><u>KER13:</u> Neuronal dysfunction (KE9) - Memory loss (AO)</strong></p>
<p style="text-align:justify">Neuronal dysfunction is one of the most well-characterized hallmarks in AD pathogenesis. Particularly, loss of memory at early stage of the disease is associated with neuronal dysfunction in the upper layer of entorhinal cortex, an early affected brain region in preclinical state of the disease [226]. Synaptic dysfunction results in cognitive impairment and neuronal cell death [202, 227, 228]. Brain insulin signaling impairment decreases AKT signaling, which is crucial for cell survival and function [229] and negatively affects synaptic plasticity and memory [230, 231]. A toxic relationship exists between soluble tau oligomers and neuroinflammation, which cause eventually neuronal damage, activating inflammatory mediators and free radicals [220, 223, 224]. In AD mouse models, chronic neuronal tumor necrosis factor α (TNF-α) expression correlates with neuronal death [232]. Significant loss in neuronal density occurs in the hippocampus and cerebral cortex of AD patients [233-235], and is AD-stage dependent [236].</p>
<p style="text-align:justify"><em>Overall assessment: </em>Despite the lack of data on quantity and temporality data, the evidence supports neuronal dysfunction (KE9) to be adjacent to memory loss (AO).</p>
<p>As the proposed AOP captures the defects that can occur before the manifestation of the disease, these depicted sequences of events, which can eventually lead to the targeted AO, may be helpful in defining the early stage(s) of AD development. The application of the AOP conceptual framework may help identify new biomarkers for early diagnosis, new druggable targets and develop novel therapies; however, it should be considered that this area of study is still in its infancy, and no diagnostic tests or therapeutic approaches suitable for AD have been derived from AOPs thus far.</p>
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