Endoplasmic Reticulum Thiol Redox State and Unfolded Protein Response in Aging

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DESCRIPTION (provided by applicant): My long-term goals are focused on understanding the basic mechanisms of aging and I am strongly committed to pursuing an academic career as an independent investigator. This proposal describes a comprehensive 5-year training program for my career development and transition to a tenure-track faculty position in the field of aging research. The mentored phase of the proposal will be carried out under the mentorship of Dr. Vadim Gladyshev, a well-established expert in redox biology and comparative genomics, and the co-mentorship of Dr. Gary Ruvkun, a pioneering researcher in the biology of aging, genetics and metabolism. Additionally, an advisory panel of established medical scientists with expertise in the ER unfolded protein stress response, redox signaling, and fluorescence activated cell sorting analysis consisting of Drs. Joseph Loscalzo, Gokhan Hotamisligil and Ronglih Liao will provide further scientific and career guidance. The planned career development activities will be carried out at the Brigham and Women's Hospital and Harvard Medical School, which provide an excellent research and training environment. Research plan: ER stress and protein misfolding have been shown to play an important role in aging and pathogenesis of various age-related diseases, such as diabetes, cancer and neurodegeneration. Cells adapt to accumulation of misfolded proteins in the ER by activating an evolutionary conserved protective mechanism known as the unfolded protein response (UPR). This signaling pathway restores ER homeostasis by degrading misfolded proteins, inhibiting translation, and facilitating protein folding and secretion. Although UPR dysfunction is increasingly recognized as a contributing factor to the pathophysiology of age-related diseases, the role of UPR signaling in regulating lifespan is not known. This proposal will test the hypothesis that modulating UPR signaling, either pharmacologically or genetically, can activate protective cellular stress responses and mediate lifespan extension. Our preliminary data demonstrate that constitutive up-regulation of the UPR signaling due to "mild" ER stress caused by selective inactivation of individual protein folding and maturation factors in the ER leads to increased longevity in budding yeast. We also found that extended lifespan in these ER/secretory pathway mutants is dependent on functional ER stress sensor protein, Ire1p, and is associated with ER hyperoxidation, suggesting that redox status in the ER is closely interlinked with the UPR signaling and is an important determinant of S. cerevisiae lifespan. Building upon these findings, we propose to address the following specific questions: (i) What are the mechanisms by which UPR and ER redox state regulate longevity? (ii) How protein folding capacity and redox state in the ER change with age? (iii) Can modulation of the UPR with small molecule compounds be used to improve ER stress resistance and regulate aging process? PUBLIC HEALTH RELEVANCE: Protein misfolding and aggregation have been implicated in aging and pathogenesis of various age-related diseases. Cells adapt to accumulation of misfolded proteins in the endoplasmic reticulum (ER) by activating an evolutionary conserved protective mechanism known as the unfolded protein response. This proposal is focused on studying the role of the unfolded protein response signaling in maintaining ER homeostasis and modulating lifespan in a simple model organism, budding yeast S. cerevisiae, and could advance our understanding of the basic mechanisms of aging and lead to development of new therapeutic strategies to delay the aging process in humans.