Reprogramming cell fate through nucleotide metabolism

Project Summary 1) Background, key gaps in our understanding, and important challenges to be addressed. This project aims to address crucial gaps in our understanding of nucleotide biosynthesis and its impact on cell fate determination. While conventional research has predominantly focused on nucleotide biosynthesis in relation to proliferation, recent findings from our laboratory have unveiled its unexpected role in triggering cell fate shifts. Specifically, we have observed that inhibition of nucleotide biosynthesis drives multipotent progenitor cells to transition from adipogenesis to smooth muscle cell differentiation. Our primary objective is to decipher the underlying mechanism governing how nucleotides regulate diverse cell fate outcomes both in controlled in vitro environments and complex in vivo systems. 2) Description of recent progress by the PI. During my post- doctoral work, I systematically elucidated the initial metabolic alterations linked to adipogenesis, leveraging advanced metabolomics and metabolic flux analyses. Notably, my investigations unveiled that the reprogramming of mitochondrial branched-chain amino acid (BCAA) catabolism serves as an early trigger that precedes and facilitates the transcriptional modulation of PPARg, thereby initiating adipogenesis (Zaganjor et al., 2020). These studies have provided a conceptual advance that metabolism can be targeted to reprogram cell fate. Furthermore, in a recent breakthrough, my research team at Vanderbilt demonstrated that inhibiting nucleotide biosynthesis profoundly reshapes cell fate trajectories (Shinde and Nunn et al., 2023), with a consequential impact on the mitochondrial transcriptome. The subsequent functional assays underscored that this inhibition prompts a shift in mitochondrial fuel preference from glucose to fatty acid oxidation. This intriguing observation prompted us to postulate that nucleotide biosynthesis orchestrates cellular outcomes by modulating mitochondrial metabolism. 3) Overview of future research program. Our future studies will critically assess whether fuel switching, and nucleotide biosynthesis alter gene regulatory networks to shape cellular outcomes. We will employ an innovative and ambitious interdisciplinary research program combining biochemistry, genetics, cell biology and multi-OMICS approaches to answer fundamental questions such as: What is the mechanism by which inhibition of nucleotide biosynthesis promotes smooth muscle cell differentiation? Does blocking nucleotide biosynthesis promote angiogenesis in vivo? We plan to combine our conceptual expertise in metabolism with the state-of-the-art technology to achieve our five-year vision and generate tools and a “working blueprint” by which we can fine-tune metabolic pathways to modulate cell differentiation.