Figure 7

Requirement of ER stress for efficient brown adipogenesis. (A and B) HB2 brown preadipocytes were treated with or without 5 mM of 4-PBA or 100 μM of capsaicin or both for 8 days in the presence of insulin (20 nM). (C and D) HB2 brown preadipocytes were transfected with scrambled RNA or siRNA for Xbp1. Cells were treated with or without 100 μM of capsaicin in the presence of insulin (20 nM) for 8 days. (A and C) Oil Red O staining of cells on day 8 was performed, and the dye intensity was quantified (n = 2). (B and D) The expression level of Ucp1 was examined by RT-qPCR analysis. Black bar: vehicle; Hatched bar: capsaicin. The data are presented as the mean ± SE (n = 4). *P < 0.05 vs. cells treated with vehicle and corresponding reagent (vehicle or 4-PBA (B) or vehicle or siXbp1 (D)). ^†P < 0.05 and ^‡P < 0.01 vs. cells treated with vehicle and the corresponding reagent (vehicle or capsaicin).