Obesity results from increased energy intake or defects in energy expenditure. Brown adipose tissue (BAT) is specialized for energy expenditure, a process called adaptive thermogenesis. Peroxisome proliferator activated receptor γ coactivator 1α (PGC1α) controls BAT-mediated thermogenesis by regulating the expression of Ucp1. Inhibitor of differentiation 1 (Id1) is a helix-loop-helix transcription factor that plays important roles in cell proliferation and differentiation. Here, we demonstrate a novel function of Id1 in BAT thermogenesis and programming of beige adipocytes in white adipose tissue (WAT). We found that adipose tissue-specific overexpression of Id1 causes age-associated and high-fat-diet-induced obesity in mice. Id1 suppresses BAT thermogenesis by binding to and suppressing PGC1α transcriptional activity. In WAT, Id1 is mainly localized in the stromal vascular fraction (SVF) where the adipose progenitor/precursors reside. Lack of Id1 increased beige gene and Ucp1 expression in the WAT in response to cold exposure. Furthermore, brown-like differentiation is increased in Id1-deficient mouse embryonic fibroblasts (MEFs). At the molecular level, Id1 directly interacted with and suppressed Ebf2 transcriptional activity leading to reduced expression of Prdm16, which determines beige/brown adipocyte cell fate. Overall, our study highlights the existence of novel regulatory mechanisms between Id1/PGC1α and Id1/Ebf2 in controlling brown fat metabolism which has significant implications in the treatment of obesity and its associated diseases such as diabetes.
This article contains Supplementary Data online at http://diabetes.diabetesjournals.org/lookup/suppl/doi:10.2337/db16-1079/-/DC1.
- Received September 8, 2016.
- Accepted March 1, 2017.
- © 2017 by the American Diabetes Association.