Peroxisome proliferator-activated receptor ? isoforms differentially regulate preadipocyte proliferation, apoptosis, and differentiation in chickens.

ABSTRACT: Peroxisome proliferator-activated receptor ? (PPAR?) has 2 protein isoforms (PPAR?1 and PPAR?2) generated by alternative promoter usage and alternative splicing. However, their functional uniqueness and similarity remain unclear. In the study, we investigated the effects of lentivirus-mediated overexpression of PPAR?1 and PPAR?2 on proliferation, apoptosis, and differentiation of the immortalized chicken preadipocytes. Cell Counting Kit-8 assay showed PPAR?1 and PPAR?2 overexpression markedly suppressed cell proliferation, and fluorescence activated cell sorting analysis showed that PPAR?1 and PPAR?2 overexpression caused cell cycle arrest at G0/G1 phase. Cell death detection ELISA analysis showed both PPAR?1 and PPAR?2 overexpression induced cell apoptosis. Oil red O staining and gene expression analysis showed both PPAR?1 and PPAR?2 overexpression promoted preadipocyte differentiation. In the presence of PPAR? ligand, rosiglitazone, PPAR?2 overexpression was more potent in inducing apoptosis, promoting adipogenesis, and suppressing cell proliferation than PPAR?1 overexpression. We further explored the molecular basis for their functional differences. Reporter gene assay showed that under ligand conditions, PPAR?2 overexpression resulted in 1.68-fold increase in transcription activity compared with PPAR?1. Electrophoretic mobility shift assay showed both PPAR?1 and PPAR?2 could bind to PPAR response element (PPRE) as heterodimer with retinoid X receptor alpha, and by comparison, PPAR?2 had a higher affinity for PPRE than PPAR?1. Reporter gene assay showed expression PPAR?1 and PPAR?2 similarly induced fatty acid synthase and adipocyte fatty acid-binding protein promoter activity but differentially induced lipoprotein lipase and perilipin 1 promoter activities. Coimmunoprecipitation analysis showed that PPAR?1 and PPAR?2 interacted similarly with the coactivators, Tat-interacting protein 60. Taken together, our results demonstrate that PPAR?1 and PPAR?2 differentially regulate preadipocyte proliferation, apoptosis, and differentiation as a result of their distinct and overlapping molecular functions.

SUBMITTER: Mu F 

PROVIDER: S-EPMC7705046 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature