Glucose-dependent glycosphingolipid biosynthesis fuels CD8⁺ T cell function and tumor control

Area of Science:

• Immunology
• Cell Metabolism
• Biochemistry

Background:

• Glucose is critical for T cell proliferation and function.
• The precise metabolic roles of glucose in T cells in vivo are not fully understood.

Purpose of the Study:

• To investigate the metabolic pathways glucose fuels in CD8+ T cells.
• To determine the role of glucose metabolism in T cell function and expansion in vivo.

Main Methods:

• Utilized ¹³C-based stable isotope tracing to track glucose metabolism in CD8+ T cells.
• Employed enzyme inhibition (UGP2, UGCG) to assess the impact on T cell function.
• Analyzed plasma membrane lipid raft integrity and T cell receptor (TCR) stimulation.

Main Results:

• Identified glycosphingolipid (GSL) biosynthesis as a key glucose-dependent pathway in CD8+ T cells.
• Demonstrated that inhibiting GSL synthesis impairs CD8+ T cell expansion and cytotoxic activity.
• Showed that GSL biosynthesis is essential for plasma membrane lipid raft integrity post-TCR stimulation.
• Observed reduced granzyme expression and tumor control in UGCG-deficient CD8+ T cells.

Conclusions:

• Glycosphingolipid (GSL) biosynthesis is a critical metabolic fate of glucose for CD8+ T cell responses.
• This glucose utilization for GSLs is independent of energy production and essential for T cell function in vivo.
• GSLs are vital for maintaining CD8+ T cell cytotoxic activity and anti-tumor immunity.