Adipose Tissue Gamma Delta T Cells in Aging and Obesity
Marlene Starr, PhD
Gamma delta (γδ)-T cells, better known for their roles in the skin and gut, are also abundant in adipose tissue, making up 15% of the lymphocyte population. Adipose γδ-T cells were recently shown to increase in numbers during obesity induced by high-fat diet (HFD) and young TCRδ-/- mice, deficient in γδ-T cells, show reduced markers of inflammation (IL-6, MCP1, TNFα), reduced accumulation of M1 macrophages, and improved insulin sensitivity compared to WT mice after 5-10 weeks of HFD, suggesting a role for γδ-T cells in chronic inflammation mediated by obesity. My novel preliminary data indicate that γδ-T cell populations expand 5-fold with age (24 mo vs 4 mo) in visceral adipose tissue of normal weight male C57BL/6 mice and this dramatic age-associated increase in γδ-T cells is unique to adipose tissue, not being observed in blood or spleen. γδ-T cells are the major source of IL-17 in adipose tissue, which acts locally to inhibit adipogenesis and regulate lipid and glucose uptake. Young IL-17-/- mice have improved insulin sensitivity and lower levels of circulating IL-6 compared to age-matched WT mice.
Greg Graf, Ph.D.
Division of Pharmacolgy and & Experimental Therapeutics
Nancy Webb, Ph.D.
Department of Pharmacology and Nutritional Sciences
College of Medicine