Formation and activation of thermogenic fat.

Thermogenic fat cells that convert chemical energy into heat are present in both mice and humans. Recent years have witnessed great advances in our understanding of the regulation of these adipocytes and an increased appreciation of the potential these cells have to counteract obesity. We summarize recent efforts to understand the formation of these fat cells and critically review genetic models and other experimental tools currently available to further investigate the development and activation of both classical brown and inducible beige fat cells. We also discuss recent discoveries about the epigenetic regulation of these adipocytes, and finally present emerging evidence revealing the metabolic impacts of thermogenic fat in humans.