Metabolic signaling directs the reciprocal lineage decisions of and T cells

The interaction between extrinsic factors and intrinsic signal strength governs thymocyte development, but mechanisms linking them remain elusive. We report that mTORC1 couples microenvironmental cues with metabolic programs in orchestrating reciprocal development of two fundamentally distinct lineages, and T cells. Loss of mTORC1 impairs but promotes T cell development, and disrupts metabolic remodeling of oxidative and glycolytic metabolism. Mechanistically, reactive oxygen species (ROS) controlled by mTORC1 serves as a key metabolic signal, and perturbation of redox homeostasis impinges upon fate decisions. Furthermore, singlecell RNA sequencing and genetic dissection reveal that mTORC1 links developmental signals from T cell receptors and NOTCH to coordinate metabolic activity and signal strength. Our results establish mTORC1-driven metabolic signaling as a fundamental mechanism underlying thymocyte lineage choices.

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