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AOP: 475
Title
Binding of chemicals to ionotropic glutamate receptors leads to impairment of learning and memory via loss of drebrin from dendritic spines of neurons
Short name
Graphical Representation
Point of Contact
Contributors
- Shihori Tanabe
- Yuko Sekino
- Tomoaki Shirao
- Noriko Koganezawa
Coaches
- Rex FitzGerald
OECD Information Table
OECD Project # | OECD Status | Reviewer's Reports | Journal-format Article | OECD iLibrary Published Version |
---|---|---|---|---|
1.107 | Under Development |
This AOP was last modified on October 25, 2024 08:30
Revision dates for related pages
Page | Revision Date/Time |
---|---|
Binding of agonist, Ionotropic glutamate receptors | September 16, 2017 10:15 |
Overactivation, NMDARs | July 14, 2024 11:45 |
Loss of drebrin | July 16, 2024 17:55 |
Synaptic dysfunction | January 04, 2023 18:47 |
Impairment, Learning and memory | July 26, 2024 09:54 |
Increased, Intracellular Calcium overload | June 26, 2020 04:45 |
Decrease of neuronal network function | May 28, 2018 11:36 |
Abnormality, dendritic spine morphology | July 14, 2024 10:55 |
Binding of agonist, Ionotropic glutamate receptors leads to Overactivation, NMDARs | November 29, 2016 20:44 |
Overactivation, NMDARs leads to Loss of drebrin | July 17, 2024 06:53 |
Overactivation, NMDARs leads to Increased, Intracellular Calcium overload | September 10, 2023 20:11 |
Increased, Intracellular Calcium overload leads to Loss of drebrin | October 18, 2023 01:22 |
Dendritic spine abnormality leads to Impairment, Learning and memory | July 14, 2024 20:58 |
Loss of drebrin leads to Dendritic spine abnormality | July 14, 2024 11:10 |
Dendritic spine abnormality leads to Dysfunctional synapses | July 17, 2024 04:21 |
Loss of drebrin leads to Impairment, Learning and memory | July 14, 2024 20:59 |
Dysfunctional synapses leads to Neuronal network function, Decreased | October 26, 2021 07:06 |
Dysfunctional synapses leads to Impairment, Learning and memory | December 11, 2022 21:08 |
Neuronal network function, Decreased leads to Impairment, Learning and memory | July 15, 2022 08:41 |
Sodium L-glutamate | July 14, 2024 00:36 |
amyloid beta | July 14, 2024 21:02 |
lotenone | July 14, 2024 21:03 |
Abstract
Neurotoxicity risk assessment is an important issue for regulatory agencies. Currently, chemicals with potential risks are determined by time-consuming and costly animal testing. Therefore, in vitro testing methods are needed to rapidly evaluate thousands of chemicals for which no safety data on neurotoxicity exist. In recent years, chemicals that induce learning and memory impairment are thought to increase the risk of neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease. Therefore, such risk assessment is necessary for human safety. The existing AOP No. 6 in OECD Series on AOPs (AOP48 in the AOP-Wiki) defines a molecular initiating event (MIE) as “Binding of agonists to ionotropic glutamate receptors”, causing neuronal cell death linked to impairment of learning and memory through receptor hyperactivation(1). Recent studies have shown that synaptic dysfunction precedes neuronal death in the early stages of dementia accompanied with the neurodegenerative diseases. Synaptic dysfunction is presumed as a decrease in the number of dendritic spines in neurons of the cerebral cortex and hippocampus, which are essential for learning and memory(2). Therefore, the risk for impairment of learning and memory can be assessed by the synaptic dysfunction, namely decreased number of dendritic spines(3). Dendritic spines are small actin-rich projections protruding from the dendrites of neurons that form excitatory synapses in the cortex and hippocampus(4). Drebrin is an actin-binding protein that localizes to dendritic spines and is said to play a specific role in their formation(5). Drebrin is known to decrease in Alzheimer's disease with a high correlation to symptom stage(6,7). In low-density cultures of hippocampal neurons, the number of dendritic spines can be counted as the number of drebrin clusters with immunostaining. We have developed an experimental protocol for low-density neuronal culture in 96-well plates and an algorithm that automatically counts the number of drebrin clusters by high-content imaging analysis(8). These protocols have been shown to be useful for screening chemicals that bind to the NMDA receptor. In fact, we have examined the toxicity of phencyclidine (PCP) and PCP-analogues and published results in a paper(9). We have developed not only the immunocytochemical protocol for in vitro assay using neuronal culture but also enzyme-linked immunosorbent assay (ELISA) kits to evaluate drebrin protein levels. Thus, decreased number of dendritic spines induced by chemicals can be assessed quantitatively as a loss of drebrin immunocytochemically and biochemically. Here, we propose a new AOP with the same MIE as AOP No. 6, in which loss of drebrin as KE leads to impairment of learning and memory. Studies of genetically engineered mice have shown that drebrin deficiency is directly related to synaptic dysfunction and leads to the impairment of learning and memory, even in the absence of neuronal cell death(10,11,12). This is the most important distinction between the proposed AOP and the existing AOP. Measurement of drebrin expression levels in neurons with immunocytochemistry and/or ELISA is easy and high-reproducible. The new KE, loss of drebrin, will promote accumulation of data of chemicals for neurotoxicity. The proposed AOP is expected to contribute to the development of many in vitro test for neurotoxicity and to establish in silico prediction to evaluate safety of many substances for human and environments. |
AOP Development Strategy
Context
We discovered drebrin in 1985 and have studied it extensively over many years. In 2017, we published a book as the culmination of our research, Drebrin: From Structure and Function to Physiological and Pathological Roles, as part of the Advances in Experimental Medicine and Biology series by Springer. We originally started to develope this AOP with a three-years research funfing from the Japan Chemical Industry Association (JCIA) Long-range Research Initiative (LRI) to YS from 2020 to 2022 for the research entitled "Proposal of a new AOP for the neurotoxicity and developmental neurotoxicity assessment of glutamate receptor binding agonists that cause learning and memory impairment". The new adverse outcome (AO), the learning and memory impairment, has new key events including loss of drebrin from the dendritic spines and the concsequent thin and slender shape of dendritic spines that causes synaptic dysfunction. Drebrin is an actin-binding protein that governs dendritic spine formation of CNS neurons and is responsible for the morphological plasticity of dendritic spines associated with learning and memory. The subcellular localization of drebrin is determined by glutamate receptor activity. We have improved Banker's method for low density neuronal culture system and established an immunocytochemical evaluation system of drebrin clusters cultured hippocampal neurons in 96 well plate using frozen hippocampal neurons prepared from rat embryo. We have developed an image processing algorithm for quantitative analysis of neuron count, dendrite length, and drebrin clusters from high-content image data using a confocal image cytometer. In particular, the brightness distribution analysis of drebrin clusters is highly sensitive. We have started to develop a machine learning platform for AI. From the images of immunocytochemical staining, we will clarify the indices for quantitatively evaluating the structural changes of neurons, and provide SOPs for culture techniques and analysis methods. In the future, we are planning to build an experimental system using neurons derived from human iPS cells.
Strategy
We have studied drebrin in the brain for mayn years.
Drebrin A is brain specific and drebrin E is mpre broadly expressed.
Key event "loss of drebrin" contribute to existing AOPs.
Summary of the AOP
Events:
Molecular Initiating Events (MIE)
Key Events (KE)
Adverse Outcomes (AO)
Type | Event ID | Title | Short name |
---|
MIE | 875 | Binding of agonist, Ionotropic glutamate receptors | Binding of agonist, Ionotropic glutamate receptors |
KE | 388 | Overactivation, NMDARs | Overactivation, NMDARs |
KE | 389 | Increased, Intracellular Calcium overload | Increased, Intracellular Calcium overload |
KE | 2078 | Loss of drebrin | Loss of drebrin |
KE | 2242 | Abnormality, dendritic spine morphology | Dendritic spine abnormality |
KE | 1944 | Synaptic dysfunction | Dysfunctional synapses |
KE | 386 | Decrease of neuronal network function | Neuronal network function, Decreased |
AO | 341 | Impairment, Learning and memory | Impairment, Learning and memory |
Relationships Between Two Key Events (Including MIEs and AOs)
Title | Adjacency | Evidence | Quantitative Understanding |
---|
Binding of agonist, Ionotropic glutamate receptors leads to Overactivation, NMDARs | adjacent | High | Moderate |
Overactivation, NMDARs leads to Increased, Intracellular Calcium overload | adjacent | High | High |
Increased, Intracellular Calcium overload leads to Loss of drebrin | adjacent | High | Moderate |
Loss of drebrin leads to Dendritic spine abnormality | adjacent | High | High |
Dendritic spine abnormality leads to Dysfunctional synapses | adjacent | High | High |
Dysfunctional synapses leads to Neuronal network function, Decreased | adjacent | High | Moderate |
Neuronal network function, Decreased leads to Impairment, Learning and memory | adjacent | High | Moderate |
Overactivation, NMDARs leads to Loss of drebrin | non-adjacent | High | High |
Dendritic spine abnormality leads to Impairment, Learning and memory | non-adjacent | High | High |
Loss of drebrin leads to Impairment, Learning and memory | non-adjacent | High | High |
Dysfunctional synapses leads to Impairment, Learning and memory | non-adjacent | Moderate | Moderate |
Network View
Prototypical Stressors
Life Stage Applicability
Life stage | Evidence |
---|---|
All life stages | Moderate |
Taxonomic Applicability
Term | Scientific Term | Evidence | Link |
---|---|---|---|
human | Homo sapiens | Moderate | NCBI |
Sex Applicability
Sex | Evidence |
---|---|
Unspecific | High |
Overall Assessment of the AOP
Domain of Applicability
Essentiality of the Key Events
Evidence Assessment
Known Modulating Factors
Modulating Factor (MF) | Influence or Outcome | KER(s) involved |
---|---|---|
Quantitative Understanding
Considerations for Potential Applications of the AOP (optional)
References
- Shirao T., Sekino Y. (Eds.) (2017) Drebrin. (Advances in Experimental Medicine and Biology, vol 1006) Tokyo, Springer
- Adverse Outcome Pathway on binding of agonists to ionotropic glutamate receptors in adult brain leading to excitotoxicity that mediates neuronal cell death, contributing to learning and memory impairment, Sachana M, et al. OECD Series on Adverse Outcome Pathways (2016) No. 6, OECD Publishing, Paris, doi: 10.1787/5jlr8vqgm630-en.
- Synapse pathology in Alzheimer’s disease, Griffiths J, Grant GN. Seminars in Cell and Developmental Biology (2022) doi: 10.1016/j.semcdb.2022.05.028. (review)
- Dopamine Restores Limbic Memory Loss, Dendritic Spine Structure, and NMDAR-Dependent LTD in the Nucleus Accumbens of Alcohol-Withdrawn Rats Cannizzaro C, et al. J Neurosci. (2019) Jan 30;39(5):929-943. doi: 10.1523/JNEUROSCI.1377-18.2018.
- Actin in dendritic spines: connecting dynamics to function, Hotulainen P, Hoogenraad C. J Cell Biol (2010) 17;189(4):619-29. doi: 10.1083/jcb. 201003008. (review)
- Role of actin cytoskeleton in dendritic spine morphogenesis. Sekino Y, et al. Neurochem Int. (2007) 51(2-4):92-104. doi: 10.1016/j.neuint.2007.04.029. (review)
- Drebrin, a dendritic spine protein, is manifold decreased in brains of patients with Alzheimer’s disease and Down syndrome Shim KS, Lubec G. Neurosci Lett. 2002 May 24;324(3):209-12. doi: 10.1016/s0304-3940(02)00210-0.
- Differential expression of synaptic proteins in the frontal and temporal cortex of elderly subjects with mild cognitive impairment, Counts SE, et al. J Neuropathol Exp Neurol. 2006 Jun;65(6):592-601. doi: 10.1097/00005072-200606000-00007.
- High-content imaging analysis for detecting the loss of drebrin clusters along dendrites in cultured hippocampal neurons Hanamura K, et al. J Pharmacol Toxicol Methods. (2019) 99:106607. doi: 10.1016/j.vascn.2019.106607.
- Assessment of NMDA receptor inhibition of phencyclidine analogues using a high-throughput drebrin immunocytochemical assay Mitsuoka T, et al. J Pharmacol Toxicol Methods. (2019) 99:106583. doi: 10.1016/j.vascn.2019
- Genetic disruption of the alternative splicing of drebrin gene impairs context-dependent fear learning in adulthood, Kojima N, et al. Neuroscience. (2010) 165(1):138-50. Doi: 10.1016/j.neuroscience.2009.10.016.
- Drebrin A regulates hippocampal LTP and hippocampus-dependent fear learning in adult mice, Kojima N, et al. Neuroscience. (2016) Jun 2;324:218-26. doi: 10.1016/j.neuroscience.2016.03.015.
- Effective expression of Drebrin in hippocampus improves cognitive function and alleviates lesions of Alzheimer’s disease in APP (swe)/PS1 (ΔE9) mice, Liu Y, et al. CNS Neurosci Ther. (2017) Jul;23(7):590-604. doi: 10.1111/cns.12706.