Brown Adipose Tissue Harbors a distinct subpopulation of regulatory T cells. Mus musculus

Regulatory T (Treg) cells are critical determinants of both immune responses and metabolic control. Here we show that systemic ablation of Treg cells compromised the adaptation of whole-body energy expenditure to cold exposure, correlating with impairment in thermogenic marker gene expression and massive invasion of pro-inflammatory macrophages in brown adipose tissue (BAT). Indeed, BAT harbored a unique sub-set of Treg cells characterized by a unique gene signature. As these Treg cells respond to BAT activation upon cold exposure, this study defines a BAT-specific Treg sub-set with direct implications for the regulation of energy homeostasis in response to environmental stress. Overall design: We isolated regulatory and conventional T cells from brown-adipose tissue of warm-conditioned or cold-conditioned mice. As controls, we harvested spleen-Treg and Tconv cells from warm-treated mice. Cells were isolated pooled organs and target cells purified by FACS. RNA was extracted and gene expression measured.