(505) New insights into the regulation of gamma delta T cells in diabetic wounds

Introduction/Rationale: Diabetes is a widespread metabolic disorder. One of its most severe complications is diabetic foot ulcers (DFUs)-open wounds characterized by chronic inflammation and delayed healing. DFUs are the leading cause of non‐traumatic lower limb amputations globally due to poor repair capacity and increased infection risk. Gamma delta (γδ) T cells are key immune cells involved in the skin’s defense and repair processes, making them an important population to study in the context of DFUs. The activity of γδ T cells is shaped by butyrophilin-like (BTNL) proteins. One member of this family, BTNL2, regulates T cell activation and may be altered by chronic conditions such as diabetes.

Methods: Here, we utilize an STZ-induced diabetic mouse model to investigate the role of multiple γδ T cell subsets (Vγ1–4) in both diabetic and non-diabetic skin, at steady state and during wound healing. Using GFP γδ T cell reporter mouse, flow cytometry and immunofluorescence, we assess γδ T cell activation and localization. Additionally, we examine BTNL2’s role in modulating γδ T cell activity through in vitro coculture assay.

Results: Under hyperglycemic conditions, γδ T cell subsets are dysregulated, with an increase in pro-inflammatory Vγ1 cells and a decrease in pro-repair Vγ3 dendritic epidermal T cells (DETCs). Diabetic mice display delayed wound closure six days post-injury, confirmed by H&E and Keratin 6 staining. Using the GFP γδ T cell reporter mice, we observe γδ T cell localization at the wound edge, predominantly Vγ1 cells, alongside with increased BTNL2 expression. Coculture assays reveal that BTNL2 immunomodulates human Vδ1 but not V2 γδ T cells.

Conclusion: Overall, our findings highlight the distinct roles of skin γδ T cell subsets and BTNL2 expression during wound healing and provide important clues to design BTNL2-based therapeutics that can modulate the skin T cell immune responses in chronic inflammatory conditions.