Regulation of the Autophagy Process in Organismal Aging

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PROJECT SUMMARY Autophagy is a major cellular recycling process by which cytosolic cargo is sequestered and degraded in the lysosome. This multi-step process plays important roles in development, disease, and aging. Direct links between autophagy and aging exist in multiple conserved longevity paradigms; such long-lived animals are thought to induce autophagy in a beneficial manner, yet the underlying mechanisms remain elusive. Ours and others' research have firmly established links between autophagy and longevity in the nematode C. elegans by showing that autophagy genes are required for the long lifespan of all conserved longevity paradigms tested. Moreover, our unpublished results indicate that autophagy is functionally relevant for longevity in all major tissues of the long-lived C. elegans mutants we have analyzed so far, and autophagy generally appears induced in tissues of long-lived mutants, but declines over time in wild-type animals. We and others have also shown that several transcriptional and post-translational regulators of autophagy play roles in aging, suggesting that autophagy is subject to complex regulation over time. While collectively establishing a critical role for autophagy in multiple tissues of C. elegans, these studies did not address which tissue-specific functions autophagy may control that affect organismal healthspan. Moreover, it is unclear how autophagy is temporally and spatially regulated in long-lived mutants and during normal aging. The goal of this application is to address these gaps in knowledge by using a combination of genetic, biochemical and behavioral assays primarily in C. elegans, but also in mammalian systems. Specifically, in Aim 1, we will use quantitative PCR and targeted proteomics to characterize how the autophagy process is regulated during aging in C. elegans and murine tissues. Moreover, we will use SILAC-coupled proteomics to measure degradation rates of select autophagy cargos in C. elegans tissues. In Aim 2, we will analyze tissue-specific roles for autophagy in C. elegans healthspan, and analyze the effects on health- and lifespan of overexpressing key autophagy-regulatory genes in a temporal and spatial-controlled manner. Finally, in Aim 3, we will use genetic and biochemical screening approaches to search for new regulators of autophagy, including factors important for autophagic cargo recognition. Autophagy plays critical roles in many diseases, including age-related disorders such as neurodegeneration. Understanding the regulation of autophagy and the conserved mechanisms by which autophagy affect aging in multicellular organisms like C. elegans are likely to provide new important insights not only into aging but may also help develop treatments for such age-related diseases.