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Updated: May 30, 2026
Real-time Monitoring of Mitochondrial Respiration in Cytokine-differentiated Human Primary T Cells
Published on: October 19, 2021
Regulation of T-cell survival and mitochondrial homeostasis by TSC1
Thomas F O'Brien1, Balachandra K Gorentla, Danli Xie
1Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA.
Abstract:
The mammalian target of rapamycin (mTOR) is a key regulator of cell growth and metabolism. It associates with multiple proteins and forms two distinct signaling complexes, mTORC1 and mTORC2. Accumulating evidence has revealed critical roles for intact mTOR signaling during T-cell activation and responses to microbial infection. However, the importance of mTOR regulation in T cells has yet to be explored. The TSC1/TSC2 complex has been shown to inhibit mTORC1 signaling in cell line models. We show here that deletion of TSC1 in the murine T-cell lineage results in a dramatic reduction of the peripheral T-cell pool, correlating with increased cell death. While mTORC1 is constitutively activated, mTORC2 signaling, reflected by Akt phosphorylation and activity, is decreased in TSC1-deficient T cells. Furthermore, TSC1-deficient T cells contain elevated reactive oxygen species (ROS) and exhibit decreased mitochondrial content and membrane potential, which is correlated with the activation of the intrinsic death pathway. Overall, our results demonstrate that TSC1 differentially regulates mTORC1 and mTORC2 activity, promotes T-cell survival, and is critical for normal mitochondrial homeostasis in T cells.
Insights
The TSC1/TSC2 complex is crucial for T-cell survival. Its deletion in T cells disrupts mammalian target of rapamycin (mTOR) signaling, leading to cell death and impaired mitochondrial function.
Area of Science:
- Immunology
- Cell Biology
- Metabolism
Background:
- Mammalian target of rapamycin (mTOR) regulates cell growth and metabolism.
- mTOR forms two complexes, mTORC1 and mTORC2, with critical roles in T-cell activation and infection response.
- The TSC1/TSC2 complex inhibits mTORC1 signaling, but its role in T cells is unexplored.
Purpose of the Study:
- To investigate the role of TSC1/TSC2 complex in T-cell survival and function.
- To determine the impact of TSC1 deletion on mTORC1 and mTORC2 signaling in T cells.
- To explore the effects of TSC1 deficiency on mitochondrial homeostasis and cell death pathways in T cells.
Main Methods:
- Generated T-cell-specific TSC1-deficient mice.
- Analyzed T-cell populations, survival rates, and cell death pathways.
- Assessed mTORC1 and mTORC2 signaling by measuring Akt phosphorylation.
- Quantified reactive oxygen species (ROS) levels, mitochondrial content, and membrane potential.
Main Results:
- T-cell-specific TSC1 deletion led to a significant reduction in peripheral T cells and increased cell death.
- TSC1-deficient T cells exhibited constitutive mTORC1 activation but decreased mTORC2 signaling.
- Elevated ROS, reduced mitochondrial content, and decreased membrane potential were observed in TSC1-deficient T cells.
- These changes correlated with the activation of the intrinsic death pathway.
Conclusions:
- TSC1 differentially regulates mTORC1 and mTORC2 activity in T cells.
- TSC1 is essential for promoting T-cell survival.
- TSC1 plays a critical role in maintaining mitochondrial homeostasis within T cells.
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