Cutting Edge: mTORC2 Regulates CD8+ Effector and Memory T Cell Differentiation through Serum and Glucocorticoid...

Area of Science:

• Immunology
• Cell Biology
• Molecular Biology

Background:

• The mechanistic target of rapamycin (mTOR) pathway is crucial for T cell metabolism and differentiation.
• mTOR complex 2 (mTORC2) signaling influences T cell fate and function.
• Understanding regulators of T cell memory is vital for effective immunity and immunotherapy.

Purpose of the Study:

• To investigate the role of serum- and glucocorticoid-regulated kinase 1 (SGK1) in CD8+ T cell memory differentiation.
• To determine the impact of SGK1 deficiency on T cell responses during infection and tumor challenge.
• To elucidate the molecular mechanisms by which SGK1 affects T cell memory development.

Main Methods:

• Utilized murine models of acute infection and tumor challenge.
• Generated and analyzed CD8+ T cells deficient in SGK1.
• Assessed T cell differentiation, memory formation, and recall responses.
• Investigated signaling pathways including Foxo1 phosphorylation and nuclear translocation.

Main Results:

• SGK1-deficient CD8+ T cells exhibited an early memory precursor phenotype during acute infections.
• Mice with SGK1-deficient CD8+ T cells generated more long-lived memory T cells.
• SGK1 deficiency enhanced CD8+ T cell recall capacity upon reinfection and improved tumor rejection.
• Mechanistically, SGK1 deficiency led to decreased Foxo1 phosphorylation and increased nuclear Foxo1.

Conclusions:

• SGK1 acts as a repressor of memory CD8+ T cell differentiation.
• Targeting SGK1 can enhance the generation of long-lived memory T cells.
• SGK1 inhibition represents a potential strategy to improve vaccine efficacy and cancer immunotherapy.