Pro12Ala polymorphism in the peroxisome proliferator-activated receptor-γ ₂ (PPARγ ₂) is associated with higher levels of total cholesterol and LDL-cholesterol in male caucasian type 2 diabetes patients

Summary

The peroxisome proliferator-activated receptor-γ ₂ (PPARγ ₂) represents the transcriptional master regulator of adipocyte differentiation and therefore has been suggested as candidate gene for the pathogenesis of obesity, type 2 diabetes and related metabolic disorders. Aim of our study was to determine the frequency of a missense point mutation within exon 2 of PPARγ ₂, Pro12Ala, and its possible association with metabolic parameters as well as diabetic retinopathy (in a population-based sample of 560 (318 male ad 242 female) type 2 diabetic patients. Subsequent to genomic PCR amplification, the Hpa-II RFLP analysis was used for genotyping. Results: 436 (77.9%) subjects were homozygous for the wildtype allele (Pro/Pro), 118 (21.1%) were heterozygous (Pro/Ala) and 6 (1.1%) were homozygous for the mutated allele (Ala/Ala). Genotype frequency was calculated to be 0.81 for the wildtype and 0.19 for the mutated allele. These frequencies did not differ from non-diabetic cohorts examined earlier. In contrast to females, total cholesterol and LDL-cholesterol were significantly higher in males (Total cholesterol: 281.8 ± 51.3 vs 253.1 ± 49.8 mg/dl, p < 0.0001; LDL-cholesterol: 182.0 ± 49.2 vs 155.6 ± 42.0 mg/d, p < 0.0001) in the presence of the mutated allele as compared to the wildtype subgroup. No differences were found with respect to BMI, HbA1c, blood pressure and serum levels of leptin nor to prevalence of retinopathy. Pro12Ala polymorphism of PPARγ ₂ gene is not associated with diabetic retinopathy but is associated with dyslipidemia in male type 2 diabetic patients.

Key words:

PPARγ - Polymorphism - Adipocyte - Type 2 diabetes - Lipid metabolism

References

• 1 Altshuler D, Hirschhorn J N, Klannemark M, Lindgren C M, Vohl M C, Nemesh J, Lane C R, Schaffner S F, Bolk S, Brewer C, Tuomi T, Gaudet D, Hudson T J, Daly M, Groop L, Lander E S. The common PPARγ Pro12Ala polymorphism is associated with decreased risk of type 2 diabetes.  Nat Genet. 2000;  26 76-80
• 2 Beamer B A, Yen C J, Andersen R E, Muller D, Elahi D, Cheskin L J, Andres R, Roth J, Shuldiner A R. Association of the Pro12Ala variant in the peroxisome proliferator-activated receptor-gamma2 gene with obesity in two Caucasian populations.  Diabetes. 1998;  47 1806-1808
• 3 Brun R P, Kim J B, Hu E, Spiegelman B M. Peroxisome proliferator-activated receptor gamma and the control of adipogenesis.  Curr Opin Lipidol. 1997;  8 212-218
• 4 Clement K, Hercberg S, Passinge B, Galan P, Varroud-Vial M, Shuldiner A R, Beamer B A, Carpentier G, Guy-Grand B, Froguel P, Vaisse C. The Pro115Gln and Pro12Ala PPAR gamma gene mutations in obesity and type 2 diabetes.  Int J Obes Relat Metab Disord. 2000;  24 391-393
• 5 De Vos P, Lefebvre A M, Miller S G, Guerre-Millo M, Wong K, Saladin R, Hamann L G, Straels B, Briggs M R, Auwerx J. Thiazolidinediones repress ob gene expression in rodents via activation of peroxisome proliferator-activated receptor gamma.  J Clin Invest. 1996;  98 1004-1009
• 6 Deeb S S, Fajas L, Nemoto M, Pihlajamaki J, Mykkanen L, Kuusisto J, Laakso M, Fujimoto W, Auwerx J. A Pro12Ala substitution in PPARgamma2 associated with decreased receptor activity, lower body mass index and improved insulin sensitivity.  Nat Genet. 1998;  20 284-287
• 7 Ek J, Urhammer S A, Sorensen T I, Andersen T, Auwerx J, Pedersen O. Homozygosity of the Pro12Ala variant of the peroxisome proliferation-activated receptor-gamma2 (PPAR-gamma2): divergent modulating effects on body mass index in obese and lean Caucasian men.  Diabetologia. 1999;  42 892-895
• 8 Evans D, de Heer J, Hagemann C, Wendt D, Wolf A, Beisiegel U, Mann W A. Association between the P12A and cl413t polymorphisms in the peroxisome proliferator activated receptor γ (PPARγ) gene and type 2 diabetes.  Exp Clin Endocrinol Diabetes. 2001;  109 151-154
• 9 Fajas L, Fruchart J C, Auxerx J. Transcriptional control of adipogenesis.  Curr Opin Cell Biol. 1998;  10 165-173
• 10 Forman B M, Tontonoz P, Chen J, Brun R P, Spiegelman B M, Evans R M. 15-Deoxy-delta 12, 14-prostaglandin J2 is a ligand for the adipocyte determination factor PPAR gamma.  Cell. 1995;  83 803-812
• 11 Hamann A, Munzberg H, Buttron P, Busing B, Hinney A, Mayer H, Siegfried W, Hebebrand J, Greten H. Missense variants in the human peroxisome proliferator-activated receptor-gamma2 gene in lean and obese subjects.  Eur J Endocrinol. 1999;  141 90-92
• 12 Hollenberg A N, Susulic V S, Madura J P, Zhang B, Moller D E, Tontonoz P, Sarraf P, Spiegelman B M, Lowell B B. Functional antagonism between CCAAT/Enhancer binding protein-alpha and peroxisome proliferator-activated receptor-gamma on the leptin promoter.  J Biol Chem. 1997;  272 5283-5290
• 13 Kallen C B, Lazar M A. Antidiabetic thiazolidinediones inhibit leptin (ob) gene expression in 3T3-L1 adipocytes.  Proc Natl Acad Sci. 1996;  93 5793-5796
• 14 Kliewer S A, Lenhard J M, Willson T M, Patel I, Morris D C, Lehmann J M. A prostaglandin J2 metabolite binds peroxisome proliferator-activated receptor gamma and promotes adipocyte differentiation.  Cell. 1995;  83 813-819
• 15 Koch M, Rett K, Maerker E, Volk A, Haist K, Deninger M, Renn W, Häring H U. The PPARgamma2 amino acid polymorphism Pro 12 Ala is prevalent in offspring of Type II diabetic patients and is associated to increased insulin sensitivity in a subgroup of obese subjects.  Diabetologia. 1999;  42 758-762
• 16 Koch M, Rett K, Maerker E, Volk A, Haist K, Deninger M, Rettig A, Renn W, Häring H U. The silent PPARγ exon 6CAC^His → CAT^His polymorphism does not affect the plasma leptin levels in a collective of first degree relatives of type 2 diabetes patients from South West Germany.  Exp Clin Endocrinol Diabetes. 2000;  108 341-346
• 17 Kohner E M, Porta M. Protocols for screening and treatment of diabetic retinopathy in Europe.  Eur J Ophthal. 1991;  1 45-54
• 18 Mancini F P, Vaccaro O, Sabatino L, Tufano A, Rivellese A A, Riccardi G, Colantuoni V. Pro12Ala substitution in the peroxisome proliferator-activated receptor-gamma2 is not associated with type 2 diabetes.  Diabetes. 1999;  48 1466-1468
• 19 Martin G, Schoonjans K, Lefebvre A M, Staels B, Auwerx J. Coordinate regulation of the expression of the fatty acid transport protein and acyl-CoA synthetase genes by PPARalpha and PPARgamma activators.  J Biol Chem. 1997;  272 28210-28217
• 20 Masugi J, Tamori Y, Mori H, Koike T, Kasuga M. Inhibitory effect of a proline-to-alanine substitution at codon 12 of peroxisome proliferator-activated receptor-gamma 2 on thiazolidinedione-induced adipogenesis.  Biochem Biophys Res Commun. 2000;  268 178-182
• 21 Meirhaeghe A, Fajas L, Helbecque N, Cottel D, Auwerx J, Deeb S S, Amouyel P. Impact of the peroxisome proliferator activated receptor gaama2 Pro12Ala polymorphism on adiposity, lipids and non-insulin-dependent diabetes mellitus.  Int J Obes Relat Metab Disord. 2000;  24 155-159
• 22 Mori H, Ikegami H, Kawaguchi Y, Seino S, Yokoi N, Takeda J, Inoue I, Seino Y, Yasuda K, Hanafusa T, Yamagata K, Awata T, Kadowaki T, Hara K, Yamada N, Gotoda T, Iwasaki N, Iwamoto Y, Sanke T, Nanjo K, Oka Y, Matsutani A, Maeda E, Kasuga M. The Pro12 → Ala substitution in PPAR-γ is associated with resistance to development of diabetes i the general population. Possible involvement in impairment of insulin secretion in individuals with type 2 diabetes.  Diabetes. 2001;  50 891-894
• 23 Mori Y, Kim-Motoyama H, Katakura T, Yasuda K, Kadowaki H, Beamer B A, Shuldiner A R, Akanuma Y, Yazaki Y, Kadowaki T. Effect of the Pro12Ala variant of the human peroxisome proliferator-activated receptor gamma 2 gene on adiposity, fat distribution, and insulin sensitivity in Japanese men.  Biochem Biophys Res Commun. 1998;  251 195-198
• 24 Oh E Y, Min K M, Chung J H, Min Y K, Lee M S, Kim K W, Lee M K. Significance of Pro12Ala mutation in peroxisome proliferator-activated receptor-gamma2 in Korean diabetic and obese subjects.  J Clin Endocrinol Metab. 2000;  85 1801-1804
• 25 Ringel J, Engeli S, Distler A, Sharma A M. Pro12Ala missense mutation of the peroxisome proliferator activated receptor gamma and diabetes mellitus.  Biochem Biophys Res Commun. 1999;  254 450-453
• 26 Schäffler A, Barth N, Schmitz G, Zietz B, Palitzsch K D, Schölmerich J. Frequency and significance of the Pro12Ala and the Pro115Gln polymorphism in the gene for proliferation-activated-γ2 (PPAR-γ2) with regard to metabolic parameters in a caucasian cohort.  Endocrine. 2001;  14 369-373
• 27 Schoonjans K, Peinado-Onsurbe J, Lefebvre A M, Heyman R A, Briggs M, Deeb S, Staels B, Auwerx J. PPARalpha and PPARgamma activators direct a distinct tissue-specific transcriptional response via a PPRE in the lipoprotein lipase gene.  EMBO J. 1996;  15 5336-5348
• 28 Sears I B, MacGinnitie M A, Kovacs L G, Graves R A. Differentiation-dependent expression of the brown adipocyte uncoupling protein gene: regulation by peroxisome proliferator-activated receptor gamma.  Mol Cell Biol. 1996;  16 3410-3419
• 29 Spiegelman B M. Peroxisome proliferator-activated receptor gamma: A key regulator of adipogenesis and systemic insulin sensitivity.  Eur J Med Res. 1997;  2 457-464
• 30 SPSS Inc, SPSS for Windows 95, V. 7.5. Chicago; SPSS inc. 1997, 2000
• 31 Tontonoz P, Hu E, Devine J, Beale E G, Spiegelman B M. PPAR gamma 2 regulates adipose expression of the phosphoenolpyruvate carboxykinase gene.  Mol Cell Biol. 1995;  15 351-357
• 32 Tontonoz P, Hu E, Graves R A, Budavari A I, Spiegelman B M. mPPAR gamma 2: tissue-specific regulator of an adipocyte enhancer.  Gen Develop. 1994;  8 1224-1234
• 33 Tontonoz P, Hu E, Spiegelman B M. Stimulation of adipogenesis in fibroblasts by PPAR gamma 2, a lipid-activated transcription factor.  Cell. 1994;  79 1147-1156
• 34 Valve R, Sivenius K, Miettinen R, Pihlajamäki J, Rissanen A, Deeb S S, Auwerx J, Uusitupa M, Laakso M. Two polymorphisms in the peroxisome proliferator-activated receptor-gamma gene are associated with severe overweight among obese women.  J Clin Endocrinol Metab. 1999;  84 3708-3712
• 35 Yen C J, Beamer B A, Negri C, Silver K, Brown K A, Yarnall D P, Burns D K, Roth J, Shuldiner A R. Molecular scanning of the human peroxisome proliferator activated receptor gamma (hPPAR gamma) gene in diabetic Caucasians: identification of a Pro12Ala PPAR gamma 2 missense mutation.  Biochem Biophys Res Commun. 1997;  241 270-274
• 36 Zhang B, Graziano M P, Doebber T W, Leibowitz M D, White-Carrington S, Szalkowski D M, Hey P J, Wu M, Cullinam C A, Bailey P, Collmann B, Friedrich R, Flier J S, Strader D C, Smith R G. Down-regulation of the expression of the obese gene by an antidiabetic thiazolidinedione in Zucker diabetic fatty rats and db/db mice.  J Biol Chem. 1996;  271 9455-9459