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. 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. The metabolic syndrome, or syndrome X, is characterized by a constellation of insulin resistance, dyslipidemia, obesity, and hypertension (1Reaven G.M. Diabetes. 1988; 37: 1595-1607Crossref PubMed Google Scholar). The prevalence of the metabolic syndrome is increasing rapidly and is estimated to affect 24% of the United States population (2Ford E.S. Giles W.H. Dietz W.H. J. Am. Med. Assoc. 2002; 287: 356-359Crossref PubMed Scopus (5800) Google Scholar). Thiazolidinediones, a class of antidiabetic compounds that activate the peroxisome proliferator-activated receptor-γ (PPARγ), 1The abbreviations used are: PPARγ, peroxisome proliferator-activated receptor-γ; FFA, free fatty acid; TG, triglyceride; PPARKI, PPARγ L466A knock-in; eWAT, epididymal white adipose tissue; WT, wild type; SREBP, sterol regulatory element-binding protein; HF, high fat; KI, knock-in; 2-DG, deoxyglucose; FKOγ, fat-specific PPARγ knock-out; TNFα, tumor necrosis factor α; PCNA, proliferating cell nuclear antigen; TUNEL, terminal deoxynucleotidyltransferase-mediated UTP end labeling; RT, reverse transcription. stimulate adipocyte differentiation, lower free fatty acids (FFAs), and enhance insulin sensitivity, thereby correcting several features of the metabolic syndrome (3Mukherjee R. Davies P.J. Crombie D.L. Bischoff E.D. Cesario R.M. Jow L. Hamann L.G. Boehm M.F. Mondon C.E. Nadzan A.M. Paterniti Jr., J.R. Heyman R.A. Nature. 1997; 386: 407-410Crossref PubMed Scopus (576) Google Scholar). The insulin-sensitizing action of the thiazolidinediones suggests that PPARγ function may be central to the development and treatment of the metabolic syndrome. PPARγ is a member of the nuclear hormone receptor superfamily and plays a pivotal role in adipogenesis (4Rosen E.D. Walkey C.J. Puigserver P. Spiegelman B.M. Genes Dev. 2000; 14: 1293-1307Crossref PubMed Google Scholar, 5Rosen E.D. Spiegelman B.M. J. Biol. Chem. 2001; 276: 37731-37734Abstract Full Text Full Text PDF PubMed Scopus (1085) Google Scholar, 6Auwerx J. Diabetologia. 1999; 42: 1033-1049Crossref PubMed Scopus (583) Google Scholar). Although PPARγ is most highly expressed in adipose tissue, it is also present in colon, monocytes/macrophages, and at lower levels in many other tissues including skeletal muscle and liver (7Vidal-Puig A.J. Considine R.V. Jimenez-Linan M. Werman A. Pories W.J. Caro J.F. Flier J.S. J. Clin. Investig. 1997; 99: 2416-2422Crossref PubMed Scopus (727) Google Scholar, 8Desvergne B. Wahli W. Endocr. Rev. 1999; 20: 649-688Crossref PubMed Scopus (2746) Google Scholar). Homozygous PPARγ null mice die in utero at 10.5–11.5 days post-coitum, likely because of placental abnormalities (9Barak Y. Nelson M.C. Ong E.S. Jones Y.Z. Ruiz-Lozano P. Chien K.R. Koder A. Evans R.M. Mol. Cell. 1999; 4: 585-595Abstract Full Text Full Text PDF PubMed Scopus (1659) Google Scholar). Heterozygous PPARγ-deficient mice exhibit increased insulin sensitivity and are protected from high fat diet-induced obesity when compared with their wild-type littermates (10Kubota N. Terauchi Y. Miki H. Tamemoto H. Yamauchi T. Komeda K. Satoh S. Nakano R. Ishii C. Sugiyama T. Eto K. Tsubamoto Y. Okuno A. Murakami K. Sekihara H. Hasegawa G. Naito M. Toyoshima Y. Tanaka S. Shiota K. Kitamura T. Fujita T. Ezaki O. Aizawa S. Nagai R. Tobe K. Kimura S. Kadowaki T. Mol. Cell. 1999; 4: 597-609Abstract Full Text Full Text PDF PubMed Scopus (1225) Google Scholar, 11Miles P. Barak Y. He W. Evans R.M. Olefsky J.M. J. Clin. Investig. 2000; 105: 287-292Crossref PubMed Scopus (376) Google Scholar). These observations may be partly explained by increased serum leptin, as heterozygous PPARγ knock-out mice have decreased food intake and increased energy expenditure (10Kubota N. Terauchi Y. Miki H. Tamemoto H. Yamauchi T. Komeda K. Satoh S. Nakano R. Ishii C. Sugiyama T. Eto K. Tsubamoto Y. Okuno A. Murakami K. Sekihara H. Hasegawa G. Naito M. Toyoshima Y. Tanaka S. Shiota K. Kitamura T. Fujita T. Ezaki O. Aizawa S. Nagai R. Tobe K. Kimura S. Kadowaki T. Mol. Cell. 1999; 4: 597-609Abstract Full Text Full Text PDF PubMed Scopus (1225) Google Scholar). Cre-loxP strategies have been used to generate tissue-specific knock-outs of PPARγ function (12Akiyama T.E. Sakai S. Lambert G. Nicol C.J. Matsusue K. Pimprale S. Lee Y.H. Ricote M. Glass C.K. Brewer Jr., H.B. Gonzalez F.J. Mol. Cell. Biol. 2002; 22: 2607-2619Crossref PubMed Scopus (339) Google Scholar, 13He W. Barak Y. Hevener A. Olson P. Liao D. Le J. Nelson M. Ong E. Olefsky J.M. Evans R.M. Proc. Natl. Acad. Sci. U. S. A. 2003; 100: 15712-15717Crossref PubMed Scopus (798) Google Scholar, 14Hevener A.L. He W. Barak Y. Le J. Bandyopadhyay G. Olson P. Wilkes J. Evans R.M. Olefsky J. Nat. Med. 2003; 9: 1491-1497Crossref PubMed Scopus (420) Google Scholar, 15Matsusue K. Haluzik M. Lambert G. Yim S.H. Gavrilova O. Ward J.M. Brewer Jr., B. Reitman M.L. Gonzalez F.J. J. Clin. Investig. 2003; 111: 737-747Crossref PubMed Scopus (506) Google Scholar, 16Norris A.W. Chen L. Fisher S.J. Szanto I. Ristow M. Jozsi A.C. Hirshman M.F. Rosen E.D. Goodyear L.J. Gonzalez F.J. Spiegelman B.M. Kahn C.R. J. Clin. Investig. 2003; 112: 608-618Crossref PubMed Scopus (367) Google Scholar, 17Rosen E.D. Kulkarni R.N. Sarraf P. Ozcan U. Okada T. Hsu C.H. Eisenman D. Magnuson M.A. Gonzalez F.J. Kahn C.R. Spiegelman B.M. Mol. Cell. Biol. 2003; 23: 7222-7229Crossref PubMed Scopus (129) Google Scholar). Muscle-specific PPARγ knock-out mice show progressive insulin resistance combined with increased adipose tissue mass (14Hevener A.L. He W. Barak Y. Le J. Bandyopadhyay G. Olson P. Wilkes J. Evans R.M. Olefsky J. Nat. Med. 2003; 9: 1491-1497Crossref PubMed Scopus (420) Google Scholar, 16Norris A.W. Chen L. Fisher S.J. Szanto I. Ristow M. Jozsi A.C. Hirshman M.F. Rosen E.D. Goodyear L.J. Gonzalez F.J. Spiegelman B.M. Kahn C.R. J. Clin. Investig. 2003; 112: 608-618Crossref PubMed Scopus (367) Google Scholar). Fat-specific PPARγ knock-out mice have lipodystrophy (hypocellularity and hypertrophy), elevated plasma FFAs and triglycerides (TGs) and decreased plasma leptin and adiponectin. These mice have insulin resistance in fat and liver but not in muscle (13He W. Barak Y. Hevener A. Olson P. Liao D. Le J. Nelson M. Ong E. Olefsky J.M. Evans R.M. Proc. Natl. Acad. Sci. U. S. A. 2003; 100: 15712-15717Crossref PubMed Scopus (798) Google Scholar). There are several reports of heterozygous PPARγ mutations in humans (18Agarwal A.K. Garg A. J. Clin. Endocrinol. Metab. 2002; 87: 408-411Crossref PubMed Scopus (256) Google Scholar, 19Hegele R.A. Cao H. Frankowski C. Mathews S.T. Leff T. Diabetes. 2002; 51: 3586-3590Crossref PubMed Scopus (230) Google Scholar, 20Barroso I. Gurnell M. Crowly V.E.F. Agosttini M. Schwabw J.W. Soos M.A. Malsen G. Williams T.D. Lewis H. Schafer A.J. Chatterjee V.K.K. O'Rahilly S. Nature. 1999; 402: 880-883Crossref PubMed Scopus (1166) Google Scholar, 21Savage D.B. Tan G.D. Acerini C.L. Jebb S.A. Agostini M. Gurnell M. Williams R.L. Umpleby A.M. Thomas E.L. Bell J.D. Dixon A.K. Dunne F. Boiani R. Cinti S. Vidal-Puig A. Karpe F. Chatterjee V.K. O'Rahilly S. Diabetes. 2003; 52: 910-917Crossref PubMed Scopus (363) Google Scholar). These patients exhibit partial lipodystrophy, severe insulin resistance, steatohepatitis, and hypertension (20Barroso I. Gurnell M. Crowly V.E.F. Agosttini M. Schwabw J.W. Soos M.A. Malsen G. Williams T.D. Lewis H. Schafer A.J. Chatterjee V.K.K. O'Rahilly S. Nature. 1999; 402: 880-883Crossref PubMed Scopus (1166) Google Scholar, 21Savage D.B. Tan G.D. Acerini C.L. Jebb S.A. Agostini M. Gurnell M. Williams R.L. Umpleby A.M. Thomas E.L. Bell J.D. Dixon A.K. Dunne F. Boiani R. Cinti S. Vidal-Puig A. Karpe F. Chatterjee V.K. O'Rahilly S. Diabetes. 2003; 52: 910-917Crossref PubMed Scopus (363) Google Scholar). These clinical manifestations include many features of the metabolic syndrome and are thought to result from a combination of loss of function and the dominant negative effects of the mutant PPARγ receptors. In this study, we created a knock-in mouse model containing a PPARγ L466A mutation, shown previously to inhibit wild-type PPARγ action in vitro (22Park Y. Freedman B.D. Lee E.J. Park S. Jameson J.L. Diabetologia. 2003; 46: 365-377Crossref PubMed Scopus (264) Google Scholar). The potent dominant negative activity of the L466A mutation, located in the transactivation domain of PPARγ, is because of preserved DNA binding activity in combination with loss of coactivator binding but preserved corepressor recruitment (22Park Y. Freedman B.D. Lee E.J. Park S. Jameson J.L. Diabetologia. 2003; 46: 365-377Crossref PubMed Scopus (264) Google Scholar). Homozygous PPARγ L466A knock-in mice die in utero, but heterozygous PPARγ L466A knock-in (PPARKI) mice are viable and manifest many of the features seen in patients with dominant negative PPARγ mutations. Generation of Mice—An exon 6 fragment of PPARγ was used to screen a 129Sv/J mouse genomic library, resulting in the isolation of a 16-kb fragment of the PPARγ gene. Site-directed mutagenesis was used to mutate the leucine residue at codon 466 to alanine (L466A). Three nucleotides were modified (CCT to AGC) to generate a novel Eco47III enzyme restriction site. A targeting vector was constructed that contained most of the 16-kb clone, modified to include the L466A mutation, along with loxP-flanked neomycin and thymidine kinase cassettes in reverse orientation (Fig. 1A). The vector was linearized by KpnI digestion, electroporated into 129Sv/J R1 ES cells (23Nagy A. Rossant J. Nagy R. Abramow-Newerly W. Roder J.C. Proc. Natl. Acad. Sci. U. S. A. 1993; 90: 8424-8428Crossref PubMed Scopus (1992) Google Scholar), and subjected to selection with G418 and gancyclovir. PCR and Southern blot analysis were used to identify homologous recombination at the PPARγ locus. Two clones identified as carrying the L466A mutation were injected into murine blastocysts and implanted into pseudo-pregnant mice. Male chimeric mice were mated with female 129Sv/J mice, and germ line transmission was confirmed by PCR screening and direct sequencing. Mice were bred to CMV-Cre transgenic mice (129Sv/J background) to excise the neomycin cassette and were maintained on a 129Sv/J background. The 3-bp difference between the L466A mutated allele (CCT) and the wild-type PPARγ allele (AGC) was used to confirm genotype (Fig. 1B). Phenotypic Evaluation of Mice—Mice were housed in a pathogen-free barrier facility, maintained on a 12-h light/dark cycle, and had ad libitum access to chow (Harlan that contained from fat were by the and of the of or in with of In mice were a high fat diet that contained from fat (Harlan or from fat In other mice were from by the were on a When the were for glucose and insulin the and was between and and were by the for or by was at and glucose levels were a were a were used to serum insulin and and were in adipose or adipose tissue, and were by for for proliferating nuclear mouse and terminal deoxynucleotidyltransferase-mediated UTP end were tissues were in and were by O. were a and The of the was used to the of cells and to cell in the and liver was in tissue was with of and of The was and in of triglycerides were as previously J. Full Text PDF PubMed Google Scholar). were the and from epididymal white adipose tissue was The was subjected to treatment and and of was used as in a PCR and for were the from DNA were for PPARγ, and and of the was used as a and were to and used for in a and cell were from adipose tissue that had been from mice and in The adipose tissue was and in and the was by the The were by and was the in with 20: PPARγ and were with to the and the were by with of as previously L.J. T. Y. Y. Diabetes. PubMed Scopus Google Scholar). is expressed as the of of weight to for to the metabolic was at in mice for at for a of a The is the of the of to the of was with the of the for by as previously J.R. O. PubMed Scopus Google Scholar). and female mice were subjected to to for clamp Mice were for line was and and studies were in mice in the at Male mice, of had implanted into the and as previously Am. J. 1999; 276: Google Scholar). days were for 6 and clamp with were as previously Am. J. 1999; 276: Google Scholar). at insulin was at for the of the glucose levels were from of a glucose was at a to glucose levels at was at and at the were with of adipose tissue, and were and rapidly in for glucose uptake from the and uptake by tissues was as previously Am. J. 1999; 276: Google Scholar). are as between were the analysis of was used for Heterozygous PPARKI mice were viable and of from adipose tissue was used to of PPARγ of to for the L466A of that PPARγ L466A die in utero by (Fig. The PPARγ L466A mutant activity (22Park Y. Freedman B.D. Lee E.J. Park S. Jameson J.L. Diabetologia. 2003; 46: 365-377Crossref PubMed Scopus (264) Google Scholar). The of is with the seen in PPARγ null (9Barak Y. Nelson M.C. Ong E.S. Jones Y.Z. Ruiz-Lozano P. Chien K.R. Koder A. Evans R.M. Mol. Cell. 1999; 4: 585-595Abstract Full Text Full Text PDF PubMed Scopus (1659) Google Scholar). analysis of PPARKI and adipose tissue revealed adipocyte (Fig. PPARKI a population of with a of and in wild-type mice is of a population of PPARKI fat that were not present in mice (Fig. The of PPARKI high is than that of mice (Fig. that the decreased of the is the of in fat is or in PPARKI eWAT, for and was and and and of were not between PPARKI and eWAT, analysis was to is of in The of and in PPARKI mice was of that in mice (Fig. blot analysis that the of nuclear was in PPARKI to (Fig. In the was the of expressed in (Fig. suggests decreased of in PPARKI adipose The levels of PPARγ not between PPARKI and We also blot analysis of in adipose tissue insulin difference in the levels of or was between PPARKI and mice not PPARKI mice had gain was for PPARKI and littermates for the from of PPARKI mice less weight on a from or high fat diet from than mice (Fig. These mice had reduced with the of weight gain in PPARKI mice, food intake and were in food intake (Fig. or were (Fig. In the PPARKI mice had serum levels on a diet than mice. FFAs were elevated in mice on a but was in PPARKI mice (Fig. of insulin serum FFAs in mice by in and PPARKI mice. levels in PPARKI mice were significantly lower than in mice on a or diet (Fig. difference in serum was (Fig. for was decreased in PPARKI 6 and glucose levels were not significantly between PPARKI and and and mice on a diet. of the of PPARKI mice fatty in and hepatic steatosis. as as of a diet was in fatty were seen the central in PPARKI (Fig. The was confirmed by and not were also in PPARKI The hepatic of PPARKI mice was than that of mice (Fig. Although the hepatic to be by a diet in PPARKI the hepatic increased by when compared with a diet. mice a in hepatic on a diet. was also but was difference between PPARKI and mice not Hyperinsulinemic-euglycemic clamp studies and studies were used to insulin action in PPARKI mice. of mice were at of been subjected to a diet from or a high fat diet from for glucose and insulin levels were in PPARKI and mice on a diet (Fig. PPARKI mice on a diet in uptake and insulin resistance compared with (Fig. PPARKI mice (Fig. In clamp glucose were significantly lower in PPARKI mice on a insulin resistance (Fig. uptake into skeletal muscle was also impaired (Fig. These that PPARKI mice have insulin resistance when to a diet. on mice that female PPARKI mice are on a or diet (Fig. PPARKI not have hypertension (Fig. In this study, we created a knock-in mouse model (PPARKI) containing a dominant negative PPARγ L466A mutation, shown previously to inhibit wild-type PPARγ action in vitro. The PPARγ function in PPARKI mice to a lipodystrophy with decreased of resulting in high hepatic and diet-induced insulin The PPARKI mouse model the of PPARγ in adipose tissue and Flier J.S. J. Clin. Investig. 2000; PubMed Scopus Google Scholar). The and of may a combination of loss of function and the dominant negative activity of the PPARγ L466A were also in the heterozygous PPARγ-deficient mouse and were with insulin sensitivity (10Kubota N. Terauchi Y. Miki H. Tamemoto H. Yamauchi T. Komeda K. Satoh S. Nakano R. Ishii C. Sugiyama T. Eto K. Tsubamoto Y. Okuno A. Murakami K. Sekihara H. Hasegawa G. Naito M. Toyoshima Y. Tanaka S. Shiota K. Kitamura T. Fujita T. Ezaki O. Aizawa S. Nagai R. Tobe K. Kimura S. Kadowaki T. Mol. Cell. 1999; 4: 597-609Abstract Full Text Full Text PDF PubMed Scopus (1225) Google Scholar). The in PPARKI mice to be but have not been compared The in PPARKI mice be because are or because not and analysis not in PPARKI adipose adipocyte and function are by the of decreased of PPARγ including and and the of in PPARKI The reduced of fat in adipose tissue is with less weight gain in PPARKI mice on a or diet. weight gain and lipodystrophy in the of food intake the of increased in the PPARKI mice, but difference was by A metabolic may be or other may to the reduced weight PPARγ is in the uptake and of fatty acids adipocytes, and this been as a partial for the insulin-sensitizing effects of PPARγ G. K. B. J. Full Text Full Text PDF PubMed Scopus Google Scholar). with this role for PPARγ, PPARKI mice have increased serum of was in and PPARKI mice not uptake or of FFAs by adipose The reduced to fat in adipose tissue may to of in PPARKI mouse liver as revealed by fatty and elevated hepatic a diet not the serum FFAs or hepatic features were fatty and The of fat may be in PPARKI mice. The in the PPARKI mouse model (129Sv/J background) is to that seen in a fat-specific PPARγ knock-out was on a to be to insulin resistance (13He W. Barak Y. Hevener A. Olson P. Liao D. Le J. Nelson M. Ong E. Olefsky J.M. Evans R.M. Proc. Natl. Acad. Sci. U. S. A. 2003; 100: 15712-15717Crossref PubMed Scopus (798) Google Scholar). The mice exhibit progressive and adipocyte function because their adipose are in mice have fatty liver and increased plasma FFAs and in the but muscle insulin sensitivity to be insulin resistance and impaired glucose uptake into to fat cell function or the direct effects of FFAs and on muscle J. Clin. Investig. 2000; PubMed Scopus Google Scholar). the PPARKI mouse and the mouse severe insulin resistance in skeletal muscle These that PPARγ function in the of is not to insulin Muscle-specific PPARγ knock-out are also characterized by high levels of FFAs and levels of and exhibit insulin resistance that is by treatment (14Hevener A.L. He W. Barak Y. Le J. Bandyopadhyay G. Olson P. Wilkes J. Evans R.M. Olefsky J. Nat. Med. 2003; 9: 1491-1497Crossref PubMed Scopus (420) Google Scholar, 16Norris A.W. Chen L. Fisher S.J. Szanto I. Ristow M. Jozsi A.C. Hirshman M.F. Rosen E.D. Goodyear L.J. Gonzalez F.J. Spiegelman B.M. Kahn C.R. J. Clin. Investig. 2003; 112: 608-618Crossref PubMed Scopus (367) Google Scholar). The in the liver and adipose tissue in to the of PPARγ loss in the muscle of mice to the PPARKI mice are at the of skeletal muscle a diet. The adipose tissue may to this but the adipose tissue are not was in adipose tissue, and uptake was significantly in skeletal muscle. was not in PPARKI mice, but of muscle be to in PPARKI skeletal muscle. Humans with dominant negative PPARγ mutations exhibit features of syndrome by a partial lipodystrophy that the adipose tissue D.B. Tan G.D. Acerini C.L. Jebb S.A. Agostini M. Gurnell M. Williams R.L. Umpleby A.M. Thomas E.L. Bell J.D. Dixon A.K. Dunne F. Boiani R. Cinti S. Vidal-Puig A. Karpe F. Chatterjee V.K. O'Rahilly S. Diabetes. 2003; 52: 910-917Crossref PubMed Scopus (363) Google Scholar). The of dominant negative PPARγ mutations in with severe insulin resistance provides for the role of PPARγ in the of insulin sensitivity in humans (20Barroso I. Gurnell M. Crowly V.E.F. Agosttini M. Schwabw J.W. Soos M.A. Malsen G. Williams T.D. Lewis H. Schafer A.J. Chatterjee V.K.K. O'Rahilly S. Nature. 1999; 402: 880-883Crossref PubMed Scopus (1166) Google Scholar, 21Savage D.B. Tan G.D. Acerini C.L. Jebb S.A. Agostini M. Gurnell M. Williams R.L. Umpleby A.M. Thomas E.L. Bell J.D. Dixon A.K. Dunne F. Boiani R. Cinti S. Vidal-Puig A. Karpe F. Chatterjee V.K. O'Rahilly S. Diabetes. 2003; 52: 910-917Crossref PubMed Scopus (363) Google Scholar). The PPARγ mutation and the action of wild-type PPARγ in a dominant negative is to the of dominant negative receptor with the syndrome of resistance to hormone O. M. R. E. C. E. K. G. L. Chatterjee V.K. Proc. Natl. Acad. Sci. U. S. A. 1997; PubMed Scopus Google Scholar). We have previously shown that the L466A mutation dominant negative activity than the mouse mutant in (22Park Y. Freedman B.D. Lee E.J. Park S. Jameson J.L. Diabetologia. 2003; 46: 365-377Crossref PubMed Scopus (264) Google Scholar). In to the L466A mutant a dominant negative PPARγ knock-in mouse model not exhibit features of the metabolic syndrome N. J.R. N. J. Clin. Investig. PubMed Scopus Google Scholar). and adipose tissue were in the knock-in but it is The of insulin resistance in the mouse may dominant negative the PPARKI mouse was on a 129Sv/J background. the is to be less than the 129Sv/J Diabetologia. 2002; PubMed Scopus Google Scholar), it be to in or other The female PPARKI mice are insulin resistance, because female mice are protected from insulin resistance and in many J. PubMed Scopus Google Scholar). studies female PPARKI mice to the to this In heterozygous PPARKI mice a dominant negative PPARγ that adipocyte development and The are with reduced weight gain and metabolic in PPARKI mice. The of high FFAs is with hepatic increased hepatic and insulin resistance in PPARKI mice subjected to diet The PPARKI mouse provides in model to the relationship between impaired PPARγ function and features of the metabolic syndrome and may be to the of to this syndrome. We and for their and for with and and for with We the in by of