Intestinal tissue-resident T cell activation depends on metabolite availability

Area of Science:

• Immunology
• Cellular Metabolism
• Gastroenterology

Background:

• Tissue-resident memory (T_RM) CD8+ T cells provide rapid immune protection at epithelial barriers.
• Intraepithelial lymphocytes (IELs) are abundant T_RM cells in the small intestine, exhibiting markers of heightened activation.
• The metabolic adaptation of IELs to their specific tissue niche is not fully understood.

Purpose of the Study:

• To investigate the metabolic activity and regulation of intestinal T_RM cells (IELs).
• To determine how the tissue environment influences IEL metabolic status and activation.
• To explore the role of metabolites, particularly glucose, in controlling IEL function.

Main Methods:

• Comparative analysis of metabolic profiles between IELs and circulating CD8+ T cells.
• Assessment of glycolysis and oxidative phosphorylation (OXPHOS) in IELs.
• Investigation of metabolite availability, especially glucose, and its impact on IEL activity.

Main Results:

• IELs exhibit faster metabolic activation compared to circulating CD8+ T cells, reflecting their semiactive status.
• IEL glycolysis and OXPHOS are interdependent and rely on environmental metabolite access.
• IEL activity is significantly influenced by local metabolite availability, with glucose levels being a key determinant.

Conclusions:

• The intestinal tissue environment dictates IEL metabolic activity and activation status.
• Metabolic control, particularly via glucose availability, provides a mechanism for regulating intestinal T_RM cell function.
• Understanding IEL metabolism is crucial for managing immune responses within the intestinal epithelial barrier.