CD8+ T cells in beige adipogenesis and energy homeostasis.

Although accumulation of lymphocytes in the white adipose tissue (WAT) in obesity is linked to insulin resistance, it remains unclear whether lymphocytes also participate in the regulation of energy homeostasis in the WAT. Here, we demonstrate enhanced energy dissipation in Rag1-/- mice, increased catecholaminergic input to subcutaneous WAT, and significant beige adipogenesis. Adoptive transfer experiments demonstrated that CD8+ T cell deficiency accounts for the enhanced beige adipogenesis in Rag1-/- mice. Consistently, we identified that CD8-/- mice also presented with enhanced beige adipogenesis. The inhibitory effect of CD8+ T cells on beige adipogenesis was reversed by blockade of IFN-γ. All together, our findings identify an effect of CD8+ T cells in regulating energy dissipation in lean WAT, mediated by IFN-γ modulation of the abundance of resident immune cells and of local catecholaminergic activity. Our results provide a plausible explanation for the clinical signs of metabolic dysfunction in diseases characterized by altered CD8+ T cell abundance and suggest targeting of CD8+ T cells as a promising therapeutic approach for obesity and other diseases with altered energy homeostasis.