What activates thermogenesis when lipid droplet lipolysis is absent in brown adipocytes?

ABSTRACT

Cold exposure activates the sympathetic nervous system. It is generally thought that this sympathetic activation induces heat production by stimulating lipolysis of cytosolic lipid droplets (LDs) in brown adipocytes. However, this concept was not examined in vivo due to lack of appropriate animal models. Recently, we and others have demonstrated that LD lipolysis in brown adipocytes is not required for cold-induced nonshivering thermogenesis. Our studies uncovered an essential role of white adipose tissue (WAT) lipolysis in fueling thermogenesis during fasting. In addition, we showed that lipolysis deficiency in brown adipose tissue (BAT) induces WAT browning. This commentary further discusses the significance of our findings and how whole body may be heated up without BAT lipolysis.

KEYWORDS:

• Brown adipose tissue
• fatty acid
• glucose
• sympathetic innervation
• uncoupling protein 1
• white adipose tissue browning

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Disclosure of potential conflicts of interest

No potential conflicts of interest were disclosed.

Acknowledgments

This work was supported in part by Award Numbers R01DK085176 (L.Y.), R01DK111052-01 (L.Y.), R01DK107544 (B.X.), and R01HL107500 (B.X.) from the National Institutes of Health, 17GRNT33670590 (L.Y.) and 15GRNT25710256 (H.S.) from AHA, and 1-18-IBS-346 (L.Y.) and 7-13-IBS-159 (H.S.) from ADA.

Additional information

Funding

American Diabetes Association Research Foundation, 1-18-IBS-346, American Diabetes Association Research Foundation, 7-13-IBS-159, American Heart Association, 17GRNT33670590, National Heart, Lung, and Blood Institute, R01HL107500.