Adipose Tissue-Resident Regulatory T Cells.

Tissue-resident immune cells play critical roles in regulating tissue function and homeostasis. Obesity-associated visceral adipose tissue inflammation is attributed to the accumulation of M1 macrophages which produce inflammatory cytokines like TNF-α, IL-6, and expansion of effector T cells like Th1 cells, CD8+ cytotoxic T cells which produce interferon-γ to further add to the severity of inflammation in the visceral adipose tissue. Regulatory T cells have been reported to exert key roles in suppressing inflammation, thus maintaining the homeostasis of immune responses, and visceral adipose Tregs exert critical roles in defending against obesity-associated metabolic disorders. They inhibit the infiltration of effector T cells and facilitate the reconstitution of adipose tissue macrophages from M1 to M2 phenotype. What is more, they can take up lipids from the adipocytes through CD36 which is driven by PPARγ. Here we review the recent progress in adipose tissue-resident regulatory T cells (Tregs), a subpopulation of CD4+ T cells which suppress adipose tissue inflammation.