ROS is the major player in regulating altered autophagy and lifespan in sin-3 mutants of C. elegans

SIN3, a transcriptional corepressor has been implicated in varied functions both as transcription activator and repressor. Recent studies associated Sin3 with the macroautophagic/autophagic process as a negative regulator of Atg8 and Atg32. Though the role of SIN3 in autophagy(definition) is being explored, little is known about the overall effect of SIN3 deletion on the survival of an organism. In this study using a Caenorhabditis elegans sin-3(tm1279);him-5(e1490) strain, we demonstrate that under in vivo conditions SIN-3 differentially modulates autophagy and lifespan. We provide evidence that the enhanced autophagy and decreased lifespan observed in sin-3 deletion mutants is dependent on ROS and intracellular oxidative stress. Inability of the mutant worms to maintain redox balance along with dysregulation of enzymatic antioxidants, depletion of GSH and NADP reserves and elevation of ROS markers compromises the longevity of the worms. It is possible that the enhanced autophagic process observed in sin-3(tm1279);him-5(e1490) worms is required to compensate for oxidative stress generated in these worms. Abbreviations:cat: catalase; DCFDA: 2ʹ,7ʹ-dichlorodihydrofluoroscein diacetate; GSH: reduced glutathione; GSSG: oxidized glutathione; H2O2: hydrogen peroxide; HDAC: Histone deacetylase; HID: HDAC interacting domain; him-5: high incidence of males; HLH-30: Helix Loop Helix-30; HNE: 4-hydroxyl-2-noneal; LIPL: LIPase Like; MDA: malondialdehyde; NGM: nematode growth medium; PAH: paired amphipathic α-helix; PE: phosphatidylethanolamine; RFU: relative fluorescence unit; ROS: reactive oxygen species; sin-3/SIN3: yeast Switch Independent; SOD: superoxide dismutase; NADP: nicotinamide adenine dinucleotide phosphate; SQST-1: SeQueSTosome related-1; ATG: AuTophaGy related