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Event: 151

Key Event Title

A descriptive phrase which defines a discrete biological change that can be measured. More help

Activation, Inflammatory cytokines, chemokines, cytoprotective gene pathways

Short name

The KE short name should be a reasonable abbreviation of the KE title and is used in labelling this object throughout the AOP-Wiki. More help

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Biological Context

Structured terms, selected from a drop-down menu, are used to identify the level of biological organization for each KE. More help

Level of Biological Organization
Molecular

Cell term

The location/biological environment in which the event takes place.The biological context describes the location/biological environment in which the event takes place. For molecular/cellular events this would include the cellular context (if known), organ context, and species/life stage/sex for which the event is relevant. For tissue/organ events cellular context is not applicable. For individual/population events, the organ context is not applicable. Further information on Event Components and Biological Context may be viewed on the attached pdf. More help

Cell term
eukaryotic cell

Organ term

Key Event Components

The KE, as defined by a set structured ontology terms consisting of a biological process, object, and action with each term originating from one of 14 biological ontologies (Ives, et al., 2017; https://aopwiki.org/info_pages/2/info_linked_pages/7#List). Biological process describes dynamics of the underlying biological system (e.g., receptor signalling).Biological process describes dynamics of the underlying biological system (e.g., receptor signaling). The biological object is the subject of the perturbation (e.g., a specific biological receptor that is activated or inhibited). Action represents the direction of perturbation of this system (generally increased or decreased; e.g., ‘decreased’ in the case of a receptor that is inhibited to indicate a decrease in the signaling by that receptor). Note that when editing Event Components, clicking an existing Event Component from the Suggestions menu will autopopulate these fields, along with their source ID and description. To clear any fields before submitting the event component, use the 'Clear process,' 'Clear object,' or 'Clear action' buttons. If a desired term does not exist, a new term request may be made via Term Requests. Event components may not be edited; to edit an event component, remove the existing event component and create a new one using the terms that you wish to add. Further information on Event Components and Biological Context may be viewed on the attached pdf. More help

Process	Object	Action
chemokine activity	Chemokine	increased
cytokine activity	Cytokine	increased

Key Event Overview

AOPs Including This Key Event

All of the AOPs that are linked to this KE will automatically be listed in this subsection. This table can be particularly useful for derivation of AOP networks including the KE.Clicking on the name of the AOP will bring you to the individual page for that AOP. More help

Taxonomic Applicability

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) that help to define the biological applicability domain of the KE.In many cases, individual species identified in these structured fields will be those for which the strongest evidence used in constructing the AOP was available in relation to this KE. More help

Term	Scientific Term	Evidence	Link
human	Homo sapiens	Moderate	NCBI

Life Stages

An indication of the the relevant life stage(s) for this KE. More help

Life stage	Evidence
All life stages

Sex Applicability

An indication of the the relevant sex for this KE. More help

Term	Evidence
Unspecific

Key Event Description

A description of the biological state being observed or measured, the biological compartment in which it is measured, and its general role in the biology should be provided. More help

The innate immune system plays a crucial role in the initiation of adaptive immune responses. (Poynter, 2012, Salazar and Ghaemmaghami, 2013) It is a first-line of defense against invading microbial pathogens and is activated via a range of pattern recognition receptors (PRRs) that recognize conserved patterns present on pathogens, that is, the toll-like receptors (TLRs) and the nucleotide binding domain leucine-rich repeat containing receptor (NLR) family. These PRRs can be activated by endogenous danger-associated molecular patterns (DAMPs), released under oxidative stress and cell damage and include components of the extracellular matrix generated after tissue injury, for example, hyaluronic acid fragments, intracellular proteins such as heat shock proteins and nonprotein DAMPs such as uric acid crystals. (Kawai and Akira, 2010, Seong and Matzinger, 2004, Wheeler et al., 2009)

NLR protein-3 (NLRP3) is a PRR that belongs to the NLR family, a group of intracellular receptors activated by mitochondrial oxidative stress, for example, by adenosine triphosphate and uric acid. (Kawai and Akira, 2009) On activation, TLR and NLRP3 activate innate immunity signaling pathways leading to the release of proinflammatory cytokines and chemokines. In recent years, increasing attention has been paid to the role of the innate immune system in asthma. The sentinel role of the innate immune systems includes the activation of pathways by pathogen-associated molecular patterns and DAMPs. By this, KEs during sensitization such as activation and migration of DCs are set into motion. (Holgate, 2012) Proinflammatory molecules are also known to induce the expression of surface molecules on immune cells such as antigen-presenting cells (APCs), which are greatly involved in the induction of adaptive immune responses. Thus, whether an immune response or tolerance response is induced in APCs depends not only on the presence of antigenic properties of a substance but also on danger signals.

How It Is Measured or Detected

A description of the type(s) of measurements that can be employed to evaluate the KE and the relative level of scientific confidence in those measurements.These can range from citation of specific validated test guidelines, citation of specific methods published in the peer reviewed literature, or outlines of a general protocol or approach (e.g., a protein may be measured by ELISA). Do not provide detailed protocols. More help

There are no predictive markers for cellular danger or proinflammatory responses described for respiratory sensitizers yet. The studies performed up until now did not result in any proteins, genes, or molecular pathways that are consistently regulated by a broad range of respiratory sensitizers or genes; (Remy et al., 2014) however, only a few chemicals have been tested. Cytokine production can be measured by ELISA or Bio-Plex systems either in the supernatants or intracellular matrix. Cell systems that can be used include also complex models such as the 3D epithelial cell models, that is, MucilAir™ and PCLS. (Huang et al., 2013, Lauenstein et al., 2014)

Activation of innate immune response can also be assessed using commercial immunoassays for signal transduction pathways, that is, p38 MAPK, JNK 1/2, and ERK 1/2. Other possible detection methods, focusing on ROS production or the induction of cytoprotective pathways, might be used as well to assess the ability of chemicals to generate endogenous danger signals (DAMPs). For ROS production, commercial assays are available that can be applied. The induction of Nrf2-KEAP1 can be assessed using the Keratinosens® (Natsch et al., 2013, Emter et al., 2010) or LuSens (Ramirez et al., 2014) assays (OECD TG 442D) and by measuring gene expression of Nrf2-dependent genes by quantitative polymerase chain reaction (qPCR), that is, HMOX, (Migdal et al., 2013) although the utility of this pathway for respiratory sensitizers is unclear. The BEAS-2B cell line, coupled with microarray analysis, reveals the PTEN pathway as potentially useful. (Verstraelen et al., 2009) The predictivity of these assays has not been studied with a large number of respiratory sensitizers.

Domain of Applicability

A description of the scientific basis for the indicated domains of applicability and the WoE calls (if provided). More help

It is not fully understood which cell types are the most important sources for the endogenous danger signals involved in sensitization of the respiratory tract. Relevant cell types representing cellular sources for danger signals are probably alveolar and bronchial epithelial cells, keratinocytes, macrophages, DCs, natural killer cells, endothelial cells, and nerve fiber endings. (Verstraelen et al., 2008) In particular, macrophages are able to respond with high levels of, for example, cytokines and ROS after stimulation of PRRs. Human cell lines representative of the cells mentioned above might be used for the measurements of danger signal induction. A limitation of the use of submerged cell lines is that certain respiratory sensitizers hydrolyze in an aqueous environment, which may lead to negative results. (Wanner et al., 2010) Air/liquid exposure in 3D skin or airway models might provide a more robust model although this has not been explored in great detail.

References

List of the literature that was cited for this KE description. More help

EMTER, R., ELLIS, G. & NATSCH, A. 2010. Performance of a novel keratinocyte-based reporter cell line to screen skin sensitizers in vitro. Toxicol Appl Pharmacol, 245, 281-90.

HOLGATE, S. T. 2012. Innate and adaptive immune responses in asthma. Nat Med, 18, 673-83.

HUANG, S., WISZNIEWSKI, L., CONSTANT, S. & ROGGEN, E. 2013. Potential of in vitro reconstituted 3D human airway epithelia (MucilAir™) to assess respiratory sensitizers. Toxicol In Vitro, 27, 1151-6.

KAWAI, T. & AKIRA, S. 2009. The roles of TLRs, RLRs and NLRs in pathogen recognition. Int Immunol, 21, 317-37.

KAWAI, T. & AKIRA, S. 2010. The role of pattern-recognition receptors in innate immunity: update on Toll-like receptors. Nat Immunol, 11, 373-84.

LAUENSTEIN, L., SWITALLA, S., PRENZLER, F., SEEHASE, S., PFENNIG, O., FÖRSTER, C., FIEGUTH, H., BRAUN, A. & SEWALD, K. 2014. Assessment of immunotoxicity induced by chemicals in human precision-cut lung slices (PCLS). Toxicol In Vitro, 28, 588-99.

MIGDAL, C., BOTTON, J., EL ALI, Z., AZOURY, M. E., GULDEMANN, J., GIMÉNEZ-ARNAU, E., LEPOITTEVIN, J. P., KERDINE-RÖMER, S. & PALLARDY, M. 2013. Reactivity of chemical sensitizers toward amino acids in cellulo plays a role in the activation of the Nrf2-ARE pathway in human monocyte dendritic cells and the THP-1 cell line. Toxicol Sci, 133, 259-74.

NATSCH, A., RYAN, C. A., FOERTSCH, L., EMTER, R., JAWORSKA, J., GERBERICK, F. & KERN, P. 2013. A dataset on 145 chemicals tested in alternative assays for skin sensitization undergoing prevalidation. J Appl Toxicol, 33, 1337-52.

POYNTER, M. E. 2012. Airway epithelial regulation of allergic sensitization in asthma. Pulm Pharmacol Ther, 25, 438-46.

RAMIREZ, T., MEHLING, A., KOLLE, S. N., WRUCK, C. J., TEUBNER, W., ELTZE, T., AUMANN, A., URBISCH, D., VAN RAVENZWAAY, B. & LANDSIEDEL, R. 2014. LuSens: a keratinocyte based ARE reporter gene assay for use in integrated testing strategies for skin sensitization hazard identification. Toxicol In Vitro, 28, 1482-97.

REMY, S., VERSTRAELEN, S., VAN DEN HEUVEL, R., NELISSEN, I., LAMBRECHTS, N., HOOYBERGHS, J. & SCHOETERS, G. 2014. Gene expressions changes in bronchial epithelial cells: markers for respiratory sensitizers and exploration of the NRF2 pathway. Toxicol In Vitro, 28, 209-17.

SALAZAR, F. & GHAEMMAGHAMI, A. M. 2013. Allergen recognition by innate immune cells: critical role of dendritic and epithelial cells. Front Immunol, 4, 356.

SEONG, S. Y. & MATZINGER, P. 2004. Hydrophobicity: an ancient damage-associated molecular pattern that initiates innate immune responses. Nat Rev Immunol, 4, 469-78.

VERSTRAELEN, S., BLOEMEN, K., NELISSEN, I., WITTERS, H., SCHOETERS, G. & VAN DEN HEUVEL, R. 2008. Cell types involved in allergic asthma and their use in in vitro models to assess respiratory sensitization. Toxicol In Vitro, 22, 1419-31.

VERSTRAELEN, S., NELISSEN, I., HOOYBERGHS, J., WITTERS, H., SCHOETERS, G., VAN CAUWENBERGE, P. & VAN DEN HEUVEL, R. 2009. Gene profiles of a human alveolar epithelial cell line after in vitro exposure to respiratory (non-)sensitizing chemicals: identification of discriminating genetic markers and pathway analysis. Toxicol Lett, 185, 16-22.

WANNER, R., SONNENBURG, A., QUATCHADZE, M., SCHREINER, M., PEISER, M., ZUBERBIER, T. & STAHLMANN, R. 2010. Classification of sensitizing and irritative potential in a combined in-vitro assay. Toxicol Appl Pharmacol, 245, 211-8.

WHEELER, D. S., CHASE, M. A., SENFT, A. P., POYNTER, S. E., WONG, H. R. & PAGE, K. 2009. Extracellular Hsp72, an endogenous DAMP, is released by virally infected airway epithelial cells and activates neutrophils via Toll-like receptor (TLR)-4. Respir Res, 10, 31.