Response to Immune Associated Stress

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PROJECT SUMMARY/ABSTRACT Nrf1/2 (human) and SKN-1 (Caenorhabditis elegans ortholog) are key infection-related transcription factors whose regulation is incompletely understood, representing a critical gap in knowledge. The long-term goal of this research is to understand how the host alleviates stress during exposure to pathogens. The objective of this application is to elucidate new mechanisms of SKN-1 regulation that contribute to its protective effects. The central hypothesis is that NIPI-3 and CDC-48.1/2 are amongst previously unknown factors that positively regulate SKN-1 to protect against immune associated stress. The rationale for this investigation is that the identification of new regulators which control a conserved stress response under pathogenic conditions may allow for their therapeutic modulation to alleviate infection induced pathology. The central hypothesis will be addressed by the following aims. Specific Aim #1 will identify how NIPI-3 regulates SKN-1 activity. The working hypothesis, based on preliminary and published data, is that NIPI-3 regulates SKN-1 activity in the intestine via CEBP-1. Specifically, NIPI-3 is proposed to negatively regulate CEBP-1, to directly influence the amount and/or activity of SKN-1 available to carry out its protective transcriptional response. Specific Aim #2 will elucidate the role of CDC-48.1/2 in influencing SKN-1 activity. CDC-48.1/2 is hypothesized to elicit its effects on SKN-1 by its role in the ER-associated degradation (ERAD) pathway. Specifically, it is proposed that CDC-48.1/2 shuttles SKN- 1A, the ER-tethered form of SKN-1, to the cytosolic side of the ER membrane, a process necessary for its activation. However, CDC-48.1/2 is additionally predicted to ensure the proper trafficking of BLI-3, a NADPH oxidase necessary for activating cytoplasmic SKN-1. Specific Aim #3 will identify additional factors that regulate SKN-1 activity and pathogen resistance. In addition to CDC-48.1/2 and NIPI-3, other factors of in- terest were found, including two that only affect SKN-1 activity on pathogen. In this aim, the screen will be com- pleted and additional factors will be characterized. The approach is postulated to reveal further insights into the mechanisms of SKN-1 regulation. Because SKN-1 and human Nrf orthologs protect against infection-related stress, the research will have a significant impact on the understanding of the cytoprotective responses that occur during the immune response. Knowledge of the targets and mechanisms that drive anti-inflammatory re- sponses may allow for their eventual pharmacological targeting for the benefit of those suffering from damaging immune responses. The proposed research is innovative because it identifies SKN-1 regulators under infectious conditions, representing a substantive departure from previous studies.