Context-specific regulatory genetic variation in MTOR dampens neutrophil-T cell crosstalk in pneumonia-associated sepsis.

Summary

This study identifies a regulatory MTOR variant (rs4845987) with cell type– and context-specific effects that downregulates T-cell MTOR, attenuates neutrophil–T cell crosstalk, and improves survival in pneumonia-associated sepsis in an endotype-dependent manner. Ex vivo experiments show that activated T cells drive immunosuppressive neutrophils via cytokines, a process mitigated by hypoxia and rapamycin, and the variant exhibits allelic effects modulated by vitamin C.

Key Findings

• Lead variant rs4845987 G-allele reduces MTOR expression in activated T cells and is associated with improved survival in pneumonia-associated sepsis.
• Cell-type opposite regulation: the regulatory element decreases MTOR in T cells but has opposite effects in neutrophils.
• Activated T cells promote immunosuppressive neutrophils via cytokines; this is dampened by hypoxia and rapamycin.
• Allele-specific modulation of the regulatory element is observed with vitamin C treatment, indicating epigenetic fine-tuning.

Clinical Implications

Supports genotype- and endotype-informed stratification in pneumonia-associated sepsis and suggests potential benefit of mTOR pathway modulation in selected patients.

Limitations

• Sample size and cohort details are not specified here; external replication in diverse populations is needed.
• Findings are endotype- and pneumonia-specific; generalizability to other sepsis sources remains to be determined.

Future Directions

Prospective, genotype-stratified interventional studies targeting mTOR signaling across sepsis endotypes; validation of allele-specific responses to metabolic or immunomodulatory therapies.