PPAR? Transcription Deficiency Exacerbates High-Fat Diet-Induced Adipocyte Hypertrophy and Insulin Resistance in Mice.

ABSTRACT: Background:The transcriptional factor peroxisome proliferator-activated receptor ? (PPAR?) is an important therapeutic target for the treatment of type 2 diabetes. However, the role of the PPAR? transcriptional activity remains ambiguous in its metabolic regulation. Methods:Based on the crystal structure of PPAR? bound with the DNA target of PPAR? response element (PPRE), Arg134, Arg135, and Arg138, three crucial DNA binding sites for PPAR?, were mutated to alanine (3RA), respectively. In vitro AlphaScreen assay and cell-based reporter assay validated that PPAR? 3RA mutant cannot bind with PPRE and lost transcriptional activity, while can still bind ligand (rosiglitazone) and cofactors (SRC1, SRC2, and NCoR). By using CRISPR/Cas9, we created mice that were heterozygous for PPAR?-3RA (PPAR?3RA/+). The phenotypes of chow diet and high-fat diet fed PPAR?3RA/+ mice were investigated, and the molecular mechanism were analyzed by assessing the PPAR? transcriptional activity. Results:Homozygous PPAR?-3RA mutant mice are embryonically lethal. The mRNA levels of PPAR? target genes were significantly decreased in PPAR?3RA/+ mice. PPAR?3RA/+ mice showed more severe adipocyte hypertrophy, insulin resistance, and hepatic steatosis than wild type mice when fed with high-fat diet. These phenotypes were ameliorated after the transcription activity of PPAR? was restored by rosiglitazone, a PPAR? agonist. Conclusion:The current report presents a novel mouse model for investigating the role of PPAR? transcription in physiological functions. The data demonstrate that the transcriptional activity plays an indispensable role for PPAR? in metabolic regulation.

SUBMITTER: Guo F 

PROVIDER: S-EPMC7466717 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature