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Updated: May 7, 2026
Real-time Monitoring of Mitochondrial Respiration in Cytokine-differentiated Human Primary T Cells
Published on: October 19, 2021
Blocking mitochondrial leucine transamination enhances T-cell activation and improves T-cell immunity against
Christie M Adam1, Tanner J Wetzel1, Sheila C Erfan1
1Department of Biochemistry and Nutrition, Des Moines University, West Des Moines, IA, USA.
Background:
T-cell metabolism is targeted by cancer cells in an attempt to escape immune surveillance. The mitochondrial branched-chain aminotransferase, BCATm, is overexpressed in cancer, yet its role in T-cell immunity is suggested but understudied.
Methods:
C57BL/6 mice with T-cell specific-single BCATm deficiency were used to determine the impact of BCATm on T-cell function in vitro and in vivo using the murine EL4-OVA lymphoma. The studies were complemented by a transcriptomic correlation analysis of BCATm in human T cells and by using siRNA to knock-down BCATm in Jurkat T cells.
Results:
The loss of BCATm from CD4+ T cells increased mitochondrial respiration but reduced the coupling between oxygen consumption and ATP synthesis, redirecting the cells to glycolysis. This compensation sustained T-cell functionality as seen by increased release of IFN-γ from CD4+ T cells or granzyme B and perforin from CD8+ T cells. Human studies further suggested that BCATm negatively affected T-cell mitochondria. While EL4-OVA tumours from T-BCATmKO mice were enriched in memory precursor CD4+ and CD8+ T cells, reduced EL4-OVA lymphoma growth was achieved in mice with T cells carrying a combined deletion of BCATm and BCATc.
Conclusions:
BCATm is an immunosuppressive enzyme that may weaken T-cell performance in the lymphoma microenvironment.
Insights
Cancer cells target T-cell metabolism, overexpressing BCATm to evade immune surveillance. This study reveals BCATm weakens T-cell function in the lymphoma microenvironment, highlighting its immunosuppressive role.
Area of Science:
- Immunology
- Cancer Biology
- Cell Metabolism
Background:
- T-cell metabolism is crucial for immune surveillance and is often exploited by cancer cells.
- Mitochondrial branched-chain aminotransferase (BCATm) is overexpressed in cancer, but its role in T-cell immunity is not well understood.
Purpose of the Study:
- To investigate the impact of BCATm on T-cell function and immunity in the context of cancer.
- To determine if BCATm plays a role in T-cell evasion of immune surveillance within the tumor microenvironment.
Main Methods:
- Utilized T-cell specific BCATm-deficient C57BL/6 mice and the EL4-OVA lymphoma model for in vitro and in vivo studies.
- Performed transcriptomic correlation analysis in human T cells and siRNA-mediated knockdown in Jurkat T cells to complement mouse studies.
Main Results:
- Loss of BCATm in CD4+ T cells enhanced mitochondrial respiration and shifted cells towards glycolysis, sustaining T-cell functionality (increased IFN-γ, granzyme B, perforin release).
- BCATm was found to negatively impact T-cell mitochondria in human cells.
- EL4-OVA tumors in BCATm-deficient mice showed enrichment of memory precursor T cells, and combined BCATm/BCATc deletion reduced tumor growth.
Conclusions:
- BCATm acts as an immunosuppressive enzyme, potentially impairing T-cell performance within the lymphoma microenvironment.
- Targeting BCATm may represent a novel strategy to enhance anti-tumor T-cell immunity.
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