Pabalu Karunadharma

My project focuses on examining the molecular mechanism of lifespan extension due to chronic calorie restriction (CR) and rapamycin. CR is the only known non-genetic, natural intervention that leads to ~30-40% life span extension with concomitant reduction in age-related pathologies. Recent data from the intervention testing program (ITP) conducted by the NIA reported a significant lifespan extension (~9-14%) in mice fed with rapamycin added diet. Rapamycin a naturally occurring macrolide, which was first discovered in the Easter Island soil in the early 1970s. It has since made an incredible journey from soil to bench to bedside becoming a widely used drug that prevents rejection in organ transplant and combats some cancers.

We subjected young and old mice to CR and rapamycin for 10 weeks and conducted 1) translation state analysis (TSA) by polysome profiling, sequencing of polysome bound RNA by Next-generation sequencing or RNA Seq, and 2) fed mice heavy labeled Leucine containing food, harvested at sequential times, and used shotgun proteomics to analyze protein turnover. Both the TSA and high-throughput proteomic approaches provide a tremendous amount of information and highlights intriguing changes in protein translation and synthesis with these two interventions. Additionally, we have mTOR genetic mice (i.e., 4EBP1, S6K, and Raptor) that are subjected to TSA and proteomics to further elucidate the mechanism of action by CR and Rapamycin.