PPARγ Transcription Deficiency Exacerbates High-Fat Diet-Induced Adipocyte Hypertrophy and Insulin Resistance in Mice
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Updated: Dec 7, 2025
Body Composition and Metabolic Caging Analysis in High Fat Fed Mice
Published on: May 24, 2018
Fusheng Guo1, Shuangshuang Xu1, Yanlin Zhu1
1State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, China.
Background:
The transcriptional factor peroxisome proliferator-activated receptor γ (PPARγ) is an important therapeutic target for the treatment of type 2 diabetes. However, the role of the PPARγ transcriptional activity remains ambiguous in its metabolic regulation.
Methods:
Based on the crystal structure of PPARγ bound with the DNA target of PPARγ response element (PPRE), Arg134, Arg135, and Arg138, three crucial DNA binding sites for PPARγ, were mutated to alanine (3RA), respectively. In vitro AlphaScreen assay and cell-based reporter assay validated that PPARγ 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 PPARγ-3RA (PPARγ3RA/+). The phenotypes of chow diet and high-fat diet fed PPARγ3RA/+ mice were investigated, and the molecular mechanism were analyzed by assessing the PPARγ transcriptional activity.
Results:
Homozygous PPARγ-3RA mutant mice are embryonically lethal. The mRNA levels of PPARγ target genes were significantly decreased in PPARγ3RA/+ mice. PPARγ3RA/+ 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 PPARγ was restored by rosiglitazone, a PPARγ agonist.
Conclusion:
The current report presents a novel mouse model for investigating the role of PPARγ transcription in physiological functions. The data demonstrate that the transcriptional activity plays an indispensable role for PPARγ in metabolic regulation.
Insights
Peroxisome proliferator-activated receptor γ (PPARγ) transcriptional activity is crucial for metabolic regulation. Disrupting this activity in mice worsened insulin resistance and fatty liver disease, highlighting its importance in type 2 diabetes.
Area of Science:
- Metabolic Regulation
- Molecular Endocrinology
- Diabetes Research
Background:
- Peroxisome proliferator-activated receptor γ (PPARγ) is a key therapeutic target for type 2 diabetes.
- The precise role of PPARγ's transcriptional activity in metabolic control remains unclear.
Purpose of the Study:
- To investigate the specific role of PPARγ transcriptional activity in metabolic regulation.
- To develop and utilize a novel mouse model to study PPARγ function.
Main Methods:
- Mutated key DNA-binding sites of PPARγ (3RA mutant) to abolish transcriptional activity while preserving ligand-binding.
- Created heterozygous PPARγ-3RA mutant mice (PPARγ3RA/+) using CRISPR/Cas9.
- Assessed metabolic phenotypes (insulin resistance, hepatic steatosis) under different diets and analyzed PPARγ target gene expression.
Main Results:
- PPARγ-3RA mutant mice exhibited impaired PPARγ target gene expression.
- PPARγ3RA/+ mice showed exacerbated insulin resistance and hepatic steatosis on a high-fat diet.
- Phenotypic severity was reduced upon restoration of PPARγ transcriptional activity with rosiglitazone.
Conclusions:
- PPARγ transcriptional activity is essential for effective metabolic regulation.
- This study provides a valuable model for dissecting PPARγ's physiological functions in metabolism.
