Effect of peroxisome hyperplasia activated receptor γ agonists on the differentiation and function of nonadrenergic primary brown adipose tissue cells in mice with diet-induced obesity

Abstract

Objective To investigate the effect of peroxisome hyperplasia activated receptor γ(PPAR-γ) agonist(PGZ) on the differentiation and function of nonadrenergic primary brown adipose tissue cells in mice with high fat diet-induced obesity, and try to provide new treatment for obesity and type 2 diabetes. Methods Primary BAT cells were separated from high fat diet-induced C57BL/6J obesity(HFD) mice and cultured in DMEM culture medium.The primary BAT cells were divided into 10 culture dishes equally, and assigned as PGZ treatment group, and control group(treated with normal saline), 5 dishes each group. The effects of PGZ on BAT cells were assessed by quantitative real-time polymerase chain reaction(RT-PCR), Gene of BAT: uncoupling protein-1(UCP-1); elongase of very long chain fatty acids(ELOVL3); PPAR-γ co-activator-1α(PGC1-α); PPAR-γ co-activator-1β(PGC1-β); PRD1-BF-1-RIZ1 homologous domain containing protein-16(PRDM16); CCAAT/enhancer binding protein β(CEBP/β); adiponectin: adipocyte fatty acid-binding protein2(AP2); cytochrome c oxidase1(CYC1); mitochondrial transcription factor A(TFAM). Western blotting was used to assess the expression of UCP-1 protein; and Oil red O staining was applied to measure the adipogenesis function of BAT. The t test is used between two groups, ANOVA and LSD test is used between multiple groups. Results The expression of mRNA associated with BAT chararcteristic genes(UCP-1、ELOVL3、PGC1-α、PGC1-β), lipogeneic genes(AP2), mitochondrial genes(CYC1、TFAM), and differential genes(PRDM16、CEBP/β) increased in PGZ treated group when compared with those in control group, the relative expression of the genes in the two groups were listed as following: UCP-1: 1100.0±612.0, 2.0±0.4; ELOVL3: 1461.0±617.0, 2.0±1.2; PGC1-α: 8.1±2.8, 2.0±1.1; PGC1-β: 8.3±2.8, 2.0±1.3; adiponectin: 2.6±0.8, 1.0±0.7; AP2: 5.1±2.2, 1.00±0.24; CYC1: 3.1±0.8, 1.0±0.4; TFAM: 1.2±0.4, 1.00±0.25; PRDM16: 4.8±2.6, 2.0±0.3; CEBP/β: 6×108±5×108, 2.0±0.6; t=2.45-5.22, all P<0.05; the expression of BAT functional protein UCP-1 assessed by Western blotting increased in PGZ treated group than that in control(1.24±0.25 vs 1.00±0.14, t=2.63, P<0.05); the function of BAT adipogenesis measured by oil red O test increased in PGZ treated group than that in control (1.2±0.2 vs 1.0±0.1, t=2.45, P<0.05). Conclusion PPAR-γ agonist-pioglitazone(PGZ) may promote the differentiation and function of brown adipocytes. This effect may be one of the reasons for PGZ improving metabolism. Key words: Pioglitazone; Brown adipose tissue; Nonadrenergic; Uncoupling protein-1