Critical Role of Nrf2 in Innate Immune Response and Survival During Sepsis

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DESCRIPTION (provided by applicant): Our long-term objective is to understand the host factors that regulate the systemic inflammation and pathogenesis of sepsis, which affects 750,000 persons every year in United States alone and causes high mortality worldwide. We recently discovered a novel host factor, nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) that plays a critical role in determining susceptibility to sepsis by regulating a compensatory pathway that controls the induction of protective cellular antioxidants. Nrf2 is a basic leucine zipper transcription factor that regulates the expression of antioxidant genes including the glutathione pathway and heme oxygenase in response to oxidative and inflammatory stress. Global disruption of Nrf2 (Nrf2 -/-) dramatically decreased survival after cecal ligation and puncture (CLP) and endotoxin treatment relative to wild-type mice (Nrf2 +/+). We hypothesize that Nrf2 regulates a host compensatory mechanism that causes transcriptional induction of antioxidant genes, which determines survival during sepsis. Disruption of Nrf2-dependent compensatory antioxidant pathways increases mortality by exaggerating the innate immune response and predisposing lymphocytes to increase apoptosis. This proposal will shed light on the Nrf2-dependent regulation of immunopathogenesis of sepsis and survival after CLP and strives to develop an intervention strategy targeting Nrf2 with a novel small-molecule activator. Specific Aim 1: To test the hypothesis that Nrf2 determines survival after CLP by protecting against deregulation of innate immune response by maintaining cellular redox balance. Specific Aim 2: To test the hypothesis that Nrf2 improves survival after CLP by attenuating apoptosis of lymphocytes. Specific Aim 3: To test the hypothesis of intervening sepsis by increasing Nrf2 activity with a small-molecule activator. The immunopathogenesis of sepsis remains poorly understood. Nrf2 provides a novel link between the regulation of oxidative stress, the innate immune response.and survival during sepsis. These studies may lead to the development of novel strategies based on Nrf2 for intervening in sepsis and improving survival.