Sunday, June 1, 2025
6/1/2025
Metabolic control of exit from naïve pluripotency - PROJECT SUMMARY Cellular metabolic pathways exhibit remarkable plasticity across different cell types in both development and disease. In addition to accompanying changes in cell state, metabolic rewiring has been shown to drive cell fate decisions programs by altering the chromatin landscape. The deposition of chemical modifications that decorate chromatin requires the intermediates of metabolic pathways, and several enzymes that remove these marks use metabolites as part of their enzymatic reaction. Therefore, fluctuations in metabolite levels have the capacity to shape chromatin to effect cell fate-specific gene expression, but the metabolic changes that drive chromatin reorganization and the enzymes that mediate metabolic control of cell fate during early development remain largely unknown. We have previously identified specific metabolites that control self-renewal of mouse embryonic stem cells (ESCs). Whether metabolism is altered as ESCs exit the self-renewing pluripotent state, and whether these metabolic changes are required for multi-lineage differentiation remains an open question. The goal of this research proposal is to characterize the metabolic rewiring that occurs during exit from naïve pluripotency and to determine the mechanisms by which this rewiring controls mouse ESC differentiation. Our preliminary data indicate that exit from naïve pluripotency is accompanied by an increase in the mitochondrial export of citrate. In Aim 1, we will use genetic and pharmacologic approaches to target the mitochondrial citrate transporter SLC25A1 or the downstream citrate-catabolizing enzyme ATP-citrate lyase to test the hypothesis that mitochondrially-derived citrate is required for early differentiation. We will investigate whether this metabolic change regulates cell fate through the deposition of citrate-derived histone acetylation marks. Preliminary data also shows changes in cellular redox state marked by an increase in the cytosolic NAD+/NADH ratio during early differentiation. In Aim 2, we will determine if this metabolic change is required for exit from naïve pluripotency by modulating the NAD+/NADH ratio using pharmacological or genetic tools. Further experiments will identify the mechanism by which cellular redox state signals to the chromatin landscape to dictate cell fate. These studies will reveal the mechanisms of metabolic control during exit from naïve pluripotency and will provide critical insight into how metabolic regulation contributes to changes in cell identity during embryonic development. The work and training plan outlined in this proposal will be completed in the laboratory of Dr. Lydia Finley with the co-advisement of Dr. Kristian Helin at Memorial Sloan Kettering Cancer Center and will ideally prepare the applicant for further clinical training and a career as an independent physician-scientist.
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