Glycogen synthase kinase 3 controls T-cell exhaustion by regulating NFAT activation

Area of Science:

• Immunology
• Cellular Biology
• Molecular Biology

Background:

• CD8+ T cells are vital for clearing infections and cancer.
• Persistent stimulation causes CD8+ T cell exhaustion, characterized by lost function and increased inhibitory receptors.
• The role of glycogen synthase kinase 3 (GSK3) in CD8+ T cell function is not fully understood.

Purpose of the Study:

• To investigate the role of GSK3 in CD8+ T cell differentiation and function.
• To elucidate the mechanisms by which GSK3 regulates T cell exhaustion in anti-tumor immunity.

Main Methods:

• Generated mice with deleted Gsk3α and Gsk3β in activated CD8+ T cells (DKO).
• Assessed CTL differentiation and effector function during viral infections.
• Evaluated tumor growth control and T cell exhaustion in DKO mice.
• Investigated the effect of anti-PD-1 immunotherapy on tumor rejection in DKO mice.
• Analyzed the molecular mechanisms of GSK3 regulation on T cell exhaustion, including NFAT signaling and gene expression.

Main Results:

• DKO mice showed reduced CTL differentiation and effector function in viral infections.
• DKO mice exhibited impaired tumor growth control due to increased T cell exhaustion and inhibitory receptor expression.
• Anti-PD-1 immunotherapy effectively restored tumor rejection in DKO mice.
• GSK3 suppresses T cell exhaustion by inhibiting TCR-induced NFAT nuclear import, thereby reducing exhaustion-related gene expression (TOX/TOX2, PD-1).

Conclusions:

• GSK3 is essential for maintaining CD8+ T cell effector function and preventing exhaustion.
• GSK3 regulates T cell exhaustion through the NFAT signaling pathway.
• Targeting GSK3 or combining it with immunotherapy like anti-PD-1 may enhance anti-tumor immune responses.