Obesity Resistance and Enhanced Insulin Sensitivity in Ahnak.sup.-/- Mice Fed a High Fat Diet Are Related to Impaired Adipogenesis and Increased Energy Expenditure

• Published in: PloS one 2015-10, Vol.10 (10)
• Main Authors: Shin, Jae Hoon, Kim, Il Yong, Kim, Yo Na, Shin, Sun Mee, Roh, Kyung Jin, Lee, Seo Hyun, Sohn, Mira, Cho, Soo Young, Lee, Sang Hyuk, Ko, Chang-Yong, Kim, Han-Sung, Choi, Cheol Soo, Bae, Yun Soo, Seong, Je Kyung
• Format: Article
• Language: English
• Subjects: Adipose tissue; Energy metabolism; Genetic aspects; High fat diet; Physiological aspects
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0139720

Recent evidence has suggested that AHNAK expression is altered in obesity, although its role in adipose tissue development remains unclear. The objective of this study was to determine the molecular mechanism by which Ahnak influences adipogenesis and glucose homeostasis. We investigated the in vitro role of AHNAK in adipogenesis using adipose-derived mesenchymal stem cells (ADSCs) and C3H10T1/2 cells. AHNAK-KO male mice were fed a high-fat diet (HFD; 60% calories from fat) and examined for glucose and insulin tolerances, for body fat compositions, and by hyperinsulinemic-euglycemic clamping. Energy expenditures were assessed using metabolic cages and by measuring the expression levels of genes involved in thermogenesis in white or brown adipose tissues. Adipogenesis in ADSCs was impaired in AHNAK-KO mice. The loss of AHNAK led to decreased BMP4/SMAD1 signaling, resulting in the downregulation of key regulators of adipocyte differentiation (P0.05). AHNAK directly interacted with SMAD1 on the Ppar[gamma]2 promoter. Concomitantly, HFD-fed AHNAK-KO mice displayed reduced hepatosteatosis and improved metabolic profiles, including improved glucose tolerance (P