Characterization of cold‐induced remodelling reveals depot‐specific differences across and within brown and white adipose tissues in mice

R Jia, X-Q Luo, G Wang, C-X Lin, H Qiao, N Wang, T Yao, J L Barclay, J P Whitehead, X Luo, J-Q Yan

Brown and beige adipose tissue dissipate energy in the form of heat via mitochondrial uncoupling protein 1, defending against hypothermia and potentially obesity. The latter has prompted renewed interest in understanding the processes involved in browning to realize potential therapeutic benefits. To characterize the temporal profile of cold-induced changes and browning of brown and white adipose tissue in mice. Male C57BL/6J mice were singly housed in conventional cages under cold exposure (4°C) for 1, 2, 3, 4, 5 and 7 days. Food intake and body weight were measured daily. Interscapular brown adipose tissue (iBAT), inguinal subcutaneous (sWAT) and epididymal white adipose tissues (eWAT) were harvested for histological, immunohistochemical, gene and protein expression analysis. Upon cold exposure food intake increased whilst body weight and adipocyte size were transiently reduced. iBAT mass was increased whilst sWAT and eWAT were transiently decreased. A combination of morphological, genetic (Ucp-1, Pgc-1α and Elov13) and biochemical (UCP-1, PPARγ and aP2) analyses demonstrated depot-specific remodeling in response to cold exposure. Our results demonstrate differential responses to cold-induced changes across discrete BAT and WAT depots, and support the notion that the effects of short-term cold exposure are achieved by expansion, activation and increasing thermogenic capacity of iBAT, as well as browning of sWAT and, to a lesser extent, eWAT. This article is protected by copyright. All rights reserved.