A dominant negative peroxisome proliferator-activated receptor-γ knock-in mouse exhibits features of the metabolic syndrome

Peroxisome proliferator-activated receptor-γ (PPARγ), a member of the nuclear hormone receptor family, is a master regulator of adipogenesis. Humans with dominant negative PPARγ mutations have features of the metabolic syndrome (severe insulin resistance, dyslipidemia, and hypertension). We created a knock-in mouse model containing a potent dominant negative PPARγ L466A mutation, shown previously to inhibit wild-type PPARγ action in vitro. Homozygous PPARγ L466A knock-in mice die in utero. Heterozygous PPARγ L466A knock-in (PPARKI) mice exhibit hypoplastic adipocytes, hypoadiponectinemia, increased serum-free fatty acids, and hepatic steatosis. When subjected to high fat diet feeding, PPARKI mice gain significantly less weight than controls. Hyperinsulinemic-euglycemic clamp studies in PPARKI mice revealed insulin resistance and reduced glucose uptake into skeletal muscle. Female PPARKI mice exhibit hypertension independent of diet. The PPARKI mouse provides a novel model for studying the relationship between impaired PPARγ function and the metabolic syndrome.