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The juvenile visceral steatosis (JVS) mouse exhibits hereditary systemic carnitine deficiency and develops cardiac hypertrophy. The aim of this study was to clarify the characteristics of cardiac hypertrophy in the JVS mouse. Total carnitine content in JVS mouse heart was about 10% of that of control mouse heart at 4 and 8 weeks of age. The heart weight/body weight ratio was bigger in JVS mice than that in control mice at 2 weeks of age, and this difference in ratio increased with age. The wall areas of both ventricles and septum in JVS mice were larger than those of the control mice at 2 and 8 weeks. The myocyte diameter in both ventricular walls and septum in JVS mice was longer than that of the control mice. On electron microscopy, the percent of mitochondria in the myocyte was 66% in JVS mice, and 37% in control mice. The percent of lipid fraction in JVS mice was six-fold higher than that in control mice. Total content of adenine nucleotides in JVS mouse heart was about 60% of that in control mouse heart. Adenylate energy charge in JVS mouse heart was 63 and 45% of that in the control mouse heart at 4 and 8 weeks, respectively. Overall, the cardiac enlargement observed in this animal model could be accounted for by a proportional increase in the myocyte diameter in the ventricles and septum, accompanied by an increase in mitochondria. Furthermore, this cellular growth is associated with decreases in the levels of ATP and ADP, and adenylate energy charge.

The number of obese patients is increasing in Japan, due to the westernization of lifestyle. Obesity, especially visceral fat obesity, is important for the development of metabolic syndrome. Genetic factors are important for the development of obesity as well as environmental factors. Importance of genetic factors of fat distribution is also reported. Recent genome-wide association studies (GWASs) have revealed the obesity and fat distribution-related polymorphisms. GWAS will highlight a better understanding of the underlying molecular mechanisms in the regulation of obesity and distribution of body fat.

We have cloned the rhesus monkey obese cDNA and have analyzed its expression in monkeys with a wide range of body weights (lean to very obese) and with or without non-insulin-dependent diabetes mellitus to examine the relationship of ob gene expression to obesity and non-insulin-dependent diabetes mellitus. The sequence of monkey ob protein, excluding the signal peptide, showed 91% identity with the human protein. We observed a significant correlation between the level of ob mRNA and body weight. We also found a significant relationship between ob mRNA and fasting plasma insulin concentration; however, insulin stimulation during a 100-140-min euglycemic/hyperinsulinemic clamp did not result in any changes in ob mRNA levels. Circulating levels of the ob gene product leptin were also significantly correlated with body weight. These results show that ob gene expression is related to body weight and is not acutely regulated by insulin.

We have utilized the yeast two-hybrid system to identify proteins that interact with the cytoplasmic domain of the insulin receptor. We identified a human cDNA that is a splice variant of the human GRB10 homolog GRB-IR, which we term GRB10/IR-SV1 (for GRB10/GRB-IR splice variant 1). The protein encoded by the GRB10/IR-SV1 cDNA contains an SH2 domain and a pleckstrin homology domain. Cloning of a full-length human cDNA revealed a predicted coding sequence that was similar to the mouse GRB10 protein, although GRB10/IR-SV1 contained an 80-amino acid deletion. The GRB10/IR-SV1 cDNA is a splice variant of the GRB-IR cDNA such that GRB10/IR-SV1 contains an intact pleckstrin homology domain and a distinct amino terminus. The interaction of GRB10/IR-SV1 with the insulin receptor and the insulin-like growth factor I (IGF-I) receptor is mediated by the SH2 domain, and we show that glutathione S-transferase-SH2 domain fusion proteins interact specifically in vitro with the insulin receptor derived from mammalian cells. The GRB10/IR-SV1 SH2 domain also interacted with an ~135-kDa phosphoprotein from unstimulated cell lysates, an interaction that decreased after insulin stimulation. We present evidence that the GRB10/IR-SV1 protein plays a functional role in insulin and IGF-I signaling by showing that microinjection of an SH2 domain fusion protein inhibited insulin- and IGF-I-stimulated mitogenesis in fibroblasts, yet had no effect on mitogenesis induced by epidermal growth factor. Our findings suggest that GRB10/IR-SV1 may serve to positively link the insulin and IGF-I receptors to an uncharacterized mitogenic signaling pathway.

Expression of key regulatory enzymes involved in glucose metabolism was studied in the livers of Otsuka Long-Evans Tokushima fatty (OLETF) rats, a model of non-insulin dependent diabetes mellitus. The activity and mRNA levels of glucokinase and L-type pyruvate kinase was increased in the liver of OLETF rats compared with control rats. There was no such remarkable change in liver-type phosphofructokinase. The activities of glucose-6-phosphatase and fructose-1,6-biphosphatase also increase despite high plasma levels of glucose and insulin. The activity of phosphoenolpyruvate carboxykinase did not show any significant change. The mRNA levels for fructose-1,6-biphosphatase, and phosphoenolpyruvate carboxykinase exhibited no marked changes. These results suggest that the expression of glucose-6-phosphatase and fructose-1,6-biphosphatase is disordered in OLETF rats.

We examined the genetic background of nonalcoholic fatty liver disease (NAFLD) in the Japanese population, by performing a genome-wide association study (GWAS). For GWAS, 392 Japanese NAFLD subjects and 934 control individuals were analyzed. For replication studies, 172 NAFLD and 1, 012 control subjects were monitored. After quality control, 261, 540 single-nucleotide polymorphisms (SNPs) in autosomal chromosomes were analyzed using a trend test. Association analysis was also performed using multiple logistic regression analysis using genotypes, age, gender and body mass index (BMI) as independent variables. Multiple linear regression analyses were performed to evaluate allelic effect of significant SNPs on biochemical traits and histological parameters adjusted by age, gender, and BMI. Rs738409 in the PNPLA3 gene was most strongly associated with NAFLD after adjustment (P = 6.8 × 10(-14), OR = 2.05). Rs2896019, and rs381062 in the PNPLA3 gene, rs738491, rs3761472, and rs2143571 in the SAMM50 gene, rs6006473, rs5764455, and rs6006611 in the PARVB gene had also significant P values (

Recent genome-wide association studies have identified several single-nucleotide polymorphisms (SNPs) that are associated with body mass index (BMI)/obesity. As obesity is an independent risk factor for hypertension, the objective of the study was to investigate the associations of obesity susceptibility loci with blood pressure (BP)/hypertension in a population of Chinese children. This was a genotype–phenotype association study. Participants included 3077 Chinese children, aged 6–18 years. Based on the Chinese age- and sex-specific BP standards, 619 hypertensive cases and 2458 controls with normal BP were identified. BP was measured by auscultation using a standard clinical sphygmomanometer. Of the 11 SNPs, only FTO rs9939609 was significantly associated with systolic BP (SBP; P=0.034) and three SNPs were significantly associated with diastolic BP (DBP; GNPDA2 rs10938397: P=0.026; FAIM2 rs7138803: P=0.015; NPC1 rs1805081: P=0.031) after adjustment for age, sex and hypertension status. In addition, three SNPs were significantly associated with hypertension risk after adjustment for age and sex (FTO rs9939609: odds ratio (OR)=1.35, 95% confidence interval (CI) 1.12–1.62, P=0.001; MC4R rs17782313: OR=1.22, 95% CI 1.06–1.42, P=0.007; GNPDA2 rs10938397: OR=1.17, 95% CI 1.02–1.34, P=0.021). After additional adjustment for BMI, none remained significant. The genetic risk score (GRS), based on three significant SNPs (FTO rs9939609, MC4R rs17782313, GNPDA2 rs10938397), showed a positive association with SBP (P=5.17 × 10−4) and risk of hypertension (OR=1.22, 95% CI 1.12–1.33, P=6.07 × 10−6). Further adjustment for BMI abolished the positive associations (SBP: P=0.220; DBP: P=0.305; hypertension: P=0.052). Only FTO rs9939609 and GRS were statistically associated with hypertension risk in the age- and sex-adjusted model after correction for multiple testing. The present study demonstrated that FTO rs9939609 and combined SNPs were significantly associated with risk of hypertension, which seems to be dependent on BMI.

Context: Vaspin is an adipokine with insulin-sensitizing effects identified from visceral adipose tissues of genetically obese rats. Objective: We investigated genetic and nongenetic factors that define serum concentrations of vaspin. Design, Setting and Participants: Vaspin levels were measured with RIA in Japanese subjects with normal fasting plasma glucose (NFG; n = 259) and type 2 diabetes patients (T2D; n = 275). Single nucleotide polymorphisms (SNP) at SERPINA12 (vaspin) gene locus were discovered, and five SNP were genotyped in the subjects with varied body mass index (n = 1138). Results: The level of serum vaspin in 93% of the samples was found to vary from 0.2 to nearly 2 ng/ml in NFG subjects (n = 259) and from 0.2 to nearly 3 ng/ml in T2D patients (n = 275) (Vaspin(Low) group), whereas a significant subpopulation (7%) in both groups displayed much higher levels of 10-40 ng/ml (Vaspin(High) group). In the Vaspin(Low) group, serum vaspin levels in T2D were significantly higher than healthy subjects (0.99 +/- 0.04 vs. 0.86 +/- 0.02 ng/ml; P < 0.01). Both in T2D and genotyped Japanese population, serum vaspin levels closely correlated with homeostasis model of assessment for insulin resistance rather than anthropometric parameters. By genotyping, rs77060950 tightly linked to serum vaspin levels, i.e. CC (0.6 +/- 0.4 ng/ml), CA (18.4 +/- 9.6 ng/ml), and AA (30.5 +/- 5.1 ng/ml) (P < 2 x 10(-16)). Putative GATA-2 and GATA-3 binding consensus site was found at rs77060950. Conclusions: Serum vaspin levels were related to insulin resistance, and higher levels of serum vaspin in 7% of the Japanese population are closely linked to minor allele sequence (A) of rs77060950. (J Clin Endocrinol Metab 97: E1202-E1207, 2012)

Visceral fat accumulation has an important role in the development of several metabolic disorders, such as type 2 diabetes, dyslipidemia and hypertension. New genetic loci that contribute to the development of type 2 diabetes have been identified by genome-wide association studies. To examine the association of type 2 diabetes susceptibility loci and visceral fat accumulation, we genotyped 1279 Japanese subjects (556 men and 723 women), who underwent computed tomography for measurements of visceral fat area (VFA) and subcutaneous fat area (SFA) for the following single-nucleotide polymorphisms (SNPs): NOTCH2 rs10923931, THADA rs7578597, PPARG rs1801282, ADAMTS9 rs4607103, IGF2BP2 rs1470579, VEGFA rs9472138, JAZF1 rs864745, CDKN2A/CDKN2B rs564398 and rs10811661, HHEX rs1111875 and rs5015480, TCF7L2 rs7901695, KCNQ1 rs2237892, KCNJ11 rs5215 and rs5219, EXT2 rs1113132, rs11037909, and rs3740878, MTNR1B rs10830963, DCD rs1153188, TSPAN8/LGR5 rs7961581, and FTO rs8050136 and rs9939609. None of the above SNPs were significantly associated with VFA. The FTO rs8050136 and rs9939609 risk alleles exhibited significant associations with body mass index (BMI; P=0.00088 and P=0.0010, respectively) and SFA (P=0.00013 and P=0.00017, respectively). No other SNPs were significantly associated with BMI or SFA. Our results suggest that two SNPs in the FTO gene are associated with subcutaneous fat accumulation. The contributions of other SNPs are inconclusive because of a limitation of the sample power.

Aims/hypothesis FTO harbours the strongest known obesity-susceptibility locus in Europeans. While there is growing evidence for a role for FTO in obesity risk in Asians, its association with type 2 diabetes, independently of BMI, remains inconsistent. To test whether there is an association of the FTO locus with obesity and type 2 diabetes, we conducted a meta-analysis of 32 populations including 96,551 East and South Asians. Methods All studies published on the association between FTO-rs9939609 (or proxy [r2>0.98]) and BMI, obesity or type 2 diabetes in East or South Asians were invited. Each study group analysed their data according to a standardised analysis plan. Association with type 2 diabetes was also adjusted for BMI. Random-effects meta-analyses were performed to pool all effect sizes. Results The FTO-rs9939609 minor allele increased risk of obesity by 1.25-fold/allele (p=9.0×10 -19), overweight by 1.13-fold/allele (p=1.0×10 -11) and type 2 diabetes by 1.15-fold/allele (p=5.5×10 -8). The association with type 2 diabetes was attenuated after adjustment for BMI (OR 1.10-fold/allele, p=6.6×10 -5). The FTO-rs9939609 minor allele increased BMI by 0.26 kg/m 2 per allele (p=2.8×10 -17), WHR by 0.003/allele (p=1.2×10 -6), and body fat percentage by 0.31%/allele (p=0.0005). Associations were similar using dominant models. While the minor allele is less common in East Asians (12-20%) than South Asians (30-33%), the effect of FTO variation on obesity-related traits and type 2 diabetes was similar in the two populations. Conclusions/interpretation FTO is associated with increased risk of obesity and type 2 diabetes, with effect sizes similar in East and South Asians and similar to those observed in Europeans. Furthermore, FTO is also associated with type 2 diabetes independently of BMI. © 2012 Springer-Verlag., published_or_final_version, Springer Open Choice, 25 May 2012

Effects of gene variants in the fat-mass and obesity-associated (FTO) gene (primarily rs9939609) on weight loss induced by lifestyle intervention are controversial. The aim of this study was to investigate whether FTO gene variations are associated with weight-reduction and changes in metabolic risk factors in response to a 14-week calorie restriction. In total, 204 Japanese women (aged 24-66 years; BMI ≥ 25 kg/m(2)) enrolled as subjects and attended dietary lectures instructing them on how to consume a nutritionally balanced diet of 1,200 kcal/day. Fat mass, both at baseline (P = 0.100) and after the intervention (P = 0.020), was higher in subjects with the AA genotype (n = 15; 7.3%) than in those with TT (n = 114; 55.9%) and TA (n = 75; 36.8%) genotypes. The change in fat-mass tended to be smaller in subjects with the AA genotype than in those with other genotypes (P = 0.065). However, the subjects with the risk allele could still decrease their body weight and improve metabolic risk factors significantly. Our data suggest that the impact of FTO rs9939609 in Japanese women may not be great enough to change body weight or metabolic risk factors in response to calorie restriction. Environmental and behavioral factors may overcome the effects of genes on weight reduction.

Metabolic syndrome is defined as a cluster of multiple risk factors, including central obesity, dyslipidemia, hypertension and impaired glucose tolerance, that increase cardiovascular disease morbidity and mortality. Genetic factors are important in the development of metabolic syndrome, as are environmental factors. However, the genetic background of metabolic syndrome is not yet fully clarified. There is evidence that obesity and obesity-related phenotypes are associated with variations in several genes, including NEGR1, SEC16B, TMEM18, ETV5, GNPDA2, BDNF, MTCH2, SH2B1, FTO, MAF, MC4R, KCTD15, SCG3, MTMR9, TFAP2B, MSRA, LYPLAL1, GCKR and FADS1. To investigate the relationship between metabolic syndrome and variations in these genes in the Japanese population, we genotyped 33 single-nucleotide polymorphisms (SNPs) in 19 genes from 1096 patients with metabolic syndrome and 581 control individuals who had no risk factors for metabolic syndrome. Four SNPs in the FTO gene were significantly related to metabolic syndrome: rs9939609 (P=0.00013), rs8050136 (P=0.00011), rs1558902 (P=6.6 × 10(-5)) and rs1421085 (P=7.4 × 10(-5)). rs3764220 in the SCG3 gene (P=0.0010) and rs2293855 in the MTMR9 gene (P=0.0015) were also significantly associated with metabolic syndrome. SNPs in the FTO, SCG3 and MTMR9 genes had no SNP × SNP epistatic effects on metabolic syndrome. Our data suggest that genetic variations in the FTO, SCG3 and MTMR9 genes independently influence the risk of metabolic syndrome.

Visceral fat accumulation has an important role in increasing morbidity and mortality rate by increasing the risk of developing several metabolic disorders, such as type 2 diabetes, dyslipidemia and hypertension. New genetic loci that contribute to the development of obesity have been identified by genome-wide association studies in Caucasian populations. We genotyped 1279 Japanese subjects (556 men and 723 women), who underwent computed tomography (CT) for measuring visceral fat area (VFA) and subcutaneous fat area (SFA), for the following single-nucleotide polymorphisms (SNPs): NEGR1 rs2815752, SEC16B rs10913469, TMEM18 rs6548238, ETV5 rs7647305, GNPDA2 rs10938397, BDNF rs6265 and rs925946, MTCH2 rs10838738, SH2B1 rs7498665, MAF rs1424233, and KCTD15 rs29941 and rs11084753. In the additive model, none of the SNPs were significantly associated with body mass index (BMI). The SH2B1 rs7498665 risk allele was found to be significantly associated with VFA (P=0.00047) but not with BMI or SFA. When the analysis was performed in men and women separately, no significant associations with VFA were observed (P=0.0099 in men and P=0.022 in women). None of the other SNPs were significantly associated with SFA. Our results suggest that there is a VFA-specific genetic factor and that a polymorphism in the SH2B1 gene influences the risk of visceral fat accumulation.

Aim: Genetic factors as well as environmental factors play an important role in the development of non-alcoholic fatty liver disease (NAFLD). Recently, inducible nitric oxide synthase (iNOS) was significantly higher in the severest form of non-alcoholic steatohepatitis (NASH), and nitric oxide (NO) has been determined to play an important role in the process of fibrosis in NASH. In this study, we investigated iNOS gene polymorphisms for associations with NAFLD. Methods: A total of 115 NAFLD patients, consisting of 65 patients with NASH and 50 patients with simple steatosis, in whom a positive diagnosis had been made by liver biopsy, and 435 healthy control subjects, were recruited into this study. Results: We investigated 10 single nucleotide polymorphisms (SNP) of the iNOS gene, one of which, rs1060822, had the lowest P-value in the allele frequency model (P = 0.00078) with an odds ratio (95% confidence interval) of 0.49 (0.32–0.75). Four SNP, rs2297510, rs2297511, rs2797512 and rs1060822, were significantly associated with NAFLD, even when the most conservative Bonferroni's correction was applied. Linkage disequilibrium analysis revealed that SNP rs1060822 and three other SNP, rs2297510, rs2297511 and rs2797512, were in the same block. We also investigated associations between rs1060822 genotypes and the fibrosis index, and the results of the analysis revealed an additive increase in the fibrosis index and intrahepatic iNOS mRNA expression in the patients with the T allele of rs1060822. Conclusion: This is the first study to identify genetic variations in iNOS that may influence the risk of NAFLD and liver fibrosis in NAFLD.

Both genetic and environmental factors contribute to the development of obesity. Due to the progress in single nucleotide polymorphism (SNP) genotyping techniques, it is possible to conduct genome-wide screens to identify genetic variants associated with obesity. We reported that secretogranin III (SCG3) and myotubularin-related protein 9 (MTMR9) confer susceptibility to the obesity in the Japanese population. Variations in the insulin-induced gene 2 (INSIG2) and in the fat mass and obesity associated (FTO) genes are also associated with the obesity in the Japanese. These genes are expressed in the hypothalamus and have been indicated to play important roles in the food intake.

We have cloned a full-length cDNA for rat-liver-type phosphofructokinase. The similarities of the rat liver-type phosphofructokinase mRNA to the human and mouse counterparts were 94% and 99% in their amino acid sequences and 88% and 94% in the nucleotide sequences of their coding regions, respectively. Rat liver-type phosphofructokinase mRNA was expressed in all tissues examined, but its level was regulated tissue-specifically. The nutritional and hormonal regulations of the mRNA in the liver were examined in comparison with those of two other key glycolytic enzymes, glucokinase and L-type pyruvate kinase. The level of liver-type phosphofructokinase mRNA was essenstially unchanged by starvation (72 h) or diabetes. The mRNA level also did not change significantly on refeeding starved rats on a high carbohydrate diet, or treating diabetic ones with insulin. These results suggested that rat liver-type phosphofructokinase mRNA in the liver was not under control of diet or insulin, in contrast to glucokinase and L-type pyruvate kinase.

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver injury. The spectrum of NAFLD is broad, extending from simple steatosis through nonalcoholic steatohepatitis (NASH). Iron is regarded as a putative element that interacts with oxygen radicals, and high rates of hyperferritinemia and increased hepatic iron stores have been demonstrated in NASH. We investigated serum ferritin concentrations, HFE gene mutations, and insulin resistance in Japanese NASH patients and the diagnostic utility of serum ferritin concentrations as a means of distinguishing NASH. Serum ferritin concentrations were measured in 86 patients with histopathologically verified NAFLD (24 with steatosis and 62 with NASH) and 20 control subjects, they were tested for HFE gene mutations and their insulin resistance was measured. The serum ferritin concentration was significantly higher in the NASH patients than in the patients with simple steatosis (P = 0.006). There was no significant difference between the groups in HFE gene mutation (C282Y, H63D, and S65C), and the serum ferritin level was related with insulin resistance. The area under the ROC curve was 0.732 for distinguishing NASH from simple steatosis (P = 0.005; 95% CI, 0.596-0.856). In conclusion high serum ferritin concentrations are a distinguishing feature of Japanese NASH patients independent of HFE gene mutations.

Aim: Non-alcoholic steatohepatitis (NASH) is a subset of non-alcoholic fatty liver disease (NAFLD) and sometimes progresses to cirrhosis and liver failure. In this study we analyzed the expression profile of genes and biological pathways involved in NASH in comparison with non-NASH by gene set enrichment analysis (GSEA) employing a DNA microarray technique. Methods: mRNA from liver biopsy specimens was collected from a group of NASH patients and a group of non-NASH patients. We analyzed the relative abundance of mRNA using high-density oligonucleotide microarrays containing probes for 54 675 known genes, and investigated the pathogenetic mechanisms of NASH by means of a powerful technique for analyzing molecular profiling data, GSEA. Results: The results showed that the level of expression of 27 gene sets was significantly higher and the level of expression of 25 gene sets was significantly lower in the NASH samples than in the non-NASH samples. Based on these results we created an online, publicly available, searchable database containing the data for the gene expression profiles of the NASH patients (http://www2.genome.rcast.u-tokyo.ac.jp/___/NASH/NASH_GSEA2/). Conclusion: Our data revealed differences in expression of many gene sets that are involved in the pathogenesis of NASH.

Mode of the expression of phosphofructokinase (PFK) -M and -L genes was examined in various human tissues including muscle, placenta, liver, kidney, pancreas, stomach and reticulocytes. The gross level of mRNA expression of PFK-M and -L genes was estimated by Northern analysis. Polymerase chain reaction was used to detect mRNA expressed at low levels in these tissues. Tissue-specific expression of alternatively spliced PFK-M gene transcripts was also determined by polymerase chain reaction. The results indicated that alternative splicing of PFK-M gene transcripts was controlled in a tissue-specific manner.

The genetic defect in muscle phosphofructokinase deficiency (type VII glycogenosis, Tarui disease) was investigated. Six cDNAs for muscle phosphofructokinase, including a full-length clone, were isolated from a non-amplified library of muscle from a patient. By sequence analysis of these clones, a 75-base in-frame deletion was identified. The rest of the sequence was identical to that of the normal cDNA, except for a silent base transition at position 516 (ACT (Thr) to ACC (Thr]. The deletion was located in the 3'-terminal region of exon 13 (numbered with reference to the rabbit muscle phosphofructokinase gene (Lee, C.-P., Kao, M.-C., French, B.A., Putney, S.D., and Chang, S.H. (1987) J. Biol. Chem. 262, 4195-4199]. Genomic DNA of the patient was amplified by polymerase chain reaction. Sequence analysis of the amplified DNA revealed a point mutation from G to T at the 5'-end of intron 13. This mutation changed the normal 5'-splice site of CAG:GTATGG to CAG:TTATGG. A cryptic splice site of ACT:GTGAGG located 75 bases upstream from the normal splice site was recognized and spliced in the patient.

Genetic factors are clearly involved in the development of obesity, but the genetic background of obesity remains largely unclear. Starting from 62 663 gene-based single-nucleotide polymorphisms (SNPs) in three sequential case-control association studies, we identified a replicated association between the obesity phenotype (BMI > or =30 kg/m(2)) and a SNP (rs2293855) located in the myotublarin-related protein 9 (MTMR9) gene in the chromosomal segment 8p23-p22. P-values (minor allele dominant model) of the first set (93 cases versus 649 controls) and the second set (564 cases versus 562 controls) were 0.008 and 0.0002, respectively. The association was replicated in the third set [394 cases versus 958 controls, P = 0.005, odds ratio (95% CI) =1.40 (1.11-1.78)]. The global P-value was 0.0000005. A multiple regression analysis revealed that gender, age BMI and rs2293855 genotype (minor allele dominant model) were significantly associated with both systolic and diastolic blood pressures. MTMR9 was shown to be the only gene within the haplotype block that contained SNPs associated with obesity. Both the transcript and protein of MTMR9 were detected in the rodent lateral hypothalamic area as well as in the arcuate nucleus, and the protein co-existed with orexin, melanin concentrating hormone, neuropeptide Y and proopiomelanocortin. The levels of MTMR9 transcript in the murine hypothalamic region increased after fasting and were decreased by a high-fat diet. Our data suggested that genetic variations in MTMR9 may confer a predisposition towards obesity and hypertension through regulation of hypothalamic neuropeptides.

Small heterodimer partner (SHP, NR0B2) is an atypical orphan nuclear receptor that inhibits transcriptional activation by several other nuclear receptors. We recently reported that mutations in the SHP gene are associated with insulin resistance. In the present study, we demonstrated that the SHP gene is expressed in adipose tissues. A reporter gene assay showed that a gene product of SHP increased the transcriptional activation of peroxisome proliferator-activated receptor (PPAR) gamma. SHP-mediated activation of PPARgamma was observed both in the presence and absence of the ligand of PPARgamma. Immunoprecipitation and glutathione S-transferase pull-down assay showed that SHP directly bound to PPARgamma and competed with nuclear receptor corepressor for binding to PPARgamma. Serial deletion studies indicated that the C terminus of SHP is important for PPARgamma activation. Mutant SHP proteins, which are found in naturally occurring mutation, showed less enhancing activity for PPARgamma than wild-type SHP. Our results suggest that SHP may act as an endogenous enhancer of PPARgamma.

Insulin resistance and its dreaded consequence, type 2 diabetes, are major causes of atherosclerosis. Adiponectin is an adipose-specific plasma protein that possesses anti-atherogenic properties, such as the suppression of adhesion molecule expression in vascular endothelial cells and cytokine production from macrophages. Plasma adiponectin concentrations are decreased in obese and type 2 diabetic subjects with insulin resistance. A regimen that normalizes or increases the plasma adiponectin might prevent atherosclerosis in patients with insulin resistance. In this study, we demonstrate the inducing effects of thiazolidinediones (TZDs), which are synthetic PPARγ ligands, on the expression and secretion of adiponectin in humans and rodents in vivo and in vitro. The administration of TZDs significantly increased the plasma adiponectin concentrations in insulin resistant humans and rodents without affecting their body weight. Adiponectin mRNA expression was normalized or increased by TZDs in the adipose tissues of obese mice. In cultured 3T3-L1 adipocytes, TZD derivatives enhanced the mRNA expression and secretion of adiponectin in a dose- and time-dependent manner. Furthermore, these effects were mediated through the activation of the promoter by the TZDs. On the other hand, TNF-α, which is produced more in an insulin-resistant condition, dose-dependently reduced the expression of adiponectin in adipocytes by suppressing its promoter activity. TZDs restored this inhibitory effect by TNF-α. TZDs might prevent atherosclerotic vascular disease in insulin-resistant patients by inducing the production of adiponectin through direct effect on its promoter and antagonizing the effect of TNF-α on the adiponectin promoter.

Visceral fat accumulation often accompanies various complications, such as insulin resistance, hypertension, dyslipidemia and atherosclerosis. Adipose tissue has been found to secrete various biologically active adipocytokines including free fatty acids. Accumulation of visceral fat increases the portal free fatty acids concentration to cause insulin resistance and dyslipidemia. Tumor necrosis alpha (TNF alpha) deteriorates insulin resistance in obesity. The levels of plasminogen activator inhibitor(PAI)-1 increase and plasma adiponectin concentration decreases in obesity leading to the development of vascular disease. The finding of genes specifically expressed in visceral fat and new adipocytokines should facilitate clarification of the mechanism for the development and complications of visceral fat accumulation.

BACKGROUND: Adiponectin is a collagen-like plasma protein specifically synthesized in adipose tissue. Plasma adiponectin concentrations are decreased in obesity whereas it is adipose-specific. OBJECTIVE: To clarify the significance of the genetic variations in adiponectin gene on its plasma concentrations and obesity. SUBJECTS: Two hundred and nineteen unrelated adult Japanese subjects (123 men and 96 women, age: 20–83 y, BMI: 16–43 kg/m2) including 77 obese subjects (BMI>26.4 kg/m2). MEASUREMENT: Human adiponectin gene was isolated from PAC DNA pools. Mutations in the adiponectin gene were screened by direct sequencing or restriction-fragment polymorphism. The levels of plasma adiponectin were determined by the enzyme-linked immunosorbent assay (ELISA). RESULTS: Adiponectin gene spanned 17 kb on chromosome 3q27, consisting of three exons and two introns. Within 2.1 kb of the 5′-flanking region, there were two octamer elements present in the promoter of adipsin. Two nucleotide changes were identified. One was a polymorphism (G/T) occurring in exon 2, and the other was a missense mutation (R112C) in exon 3. The mean plasma adiponectin levels of the subjects carrying G allele were low (G/G: 4.5 μg/ml; G/T: 5.9 μg/ml; and T/T: 6.3 μg/ml), but were not statistically significant. The allelic frequency between the obese and the non-obese showed no significant difference. The subject carrying R112C mutation showed markedly low concentration of plasma adiponectin. CONCLUSION: Two nucleotide changes have been identified in the adiponectin gene. G/T polymorphism in exon 2 was associated with neither plasma adiponectin concentrations nor the presence of obesity. A subject carrying missense mutation (R112C) showed markedly low plasma adiponectin concentration.

Adipose tissue is a major site of glycerol production in response to energy balance. However, molecular basis of glycerol release from adipocytes has not yet been elucidated. We recently cloned a novel member of the aquaporin family, aquaporin adipose (AQPap), which has glycerol permeability. The current study was designed to examine the hypothesis that AQPap serves as a glycerol channel in adipocytes. Adipose tissue expressed AQPap mRNA in high abundance, but not the mRNAs for the other aquaglyceroporins, AQP3 and AQP9, indicating that AQPap is the only known aquaglyceroporin expressed in adipose tissue. Glycerol release from 3T3-L1 cells was increased during differentiation in parallel with AQPap mRNA levels and suppressed by mercury ion, which inhibits the function of AQPs, supporting AQPap functions as a glycerol channel in adipocytes. Fasting increased and refeeding suppressed adipose AQPap mRNA levels in accordance with plasma glycerol levels and oppositely to plasma insulin levels in mice. Insulin dose-dependently suppressed AQPap mRNA expression in 3T3-L1 cells. AQPap mRNA levels and adipose glycerol concentrations measured by the microdialysis technique were increased in obese mice with insulin resistance. Accordingly, negative regulation of AQPap expression by insulin was impaired in the insulin-resistant state. Exposure of epinephrine translocated AQPap protein from perinuclear cytoplasm to the plasma membrane in 3T3-L1 adipocytes. These results strongly suggest that AQPap plays an important role in glycerol release from adipocytes.

To examine the expression of peroxisome proliferator-activated receptor gamma (PPARgamma) together with CCAAT/enhancer binding protein alpha (C/EBPalpha), lipoprotein lipase (LPL) and glucose transporter (GLUT4) mRNA in adipose tissue of rhesus monkeys in relation to obesity.Cloning of the PPARgamma1 and gamma2 cDNAs and analysis of PPARgamma, C/EBPalpha, LPL and GLUT4 mRNA levels in the adipose tissue of lean and obese monkeys.28 rhesus monkeys (Macaca mulatta) with a wide range of body weights (9.2-22.6 kg) and with or without type 2 diabetes.Sequence of PPARgamma1 and gamma2. Tissue distribution of PPARgamma1 and gamma2. The mRNA levels of PPARgamma, C/EBPalpha, LPL and GLUT4 in adipose tissue. The ratio of PPARgamma2 mRNA to total PPARgamma mRNA.The monkey PPARgamma2 protein showed 99% identity with the human protein. PPARgamma1 mRNA was shown to be expressed in various tissues and most abundantly in adipose tissue. PPARgamma2 existed mainly in adipose tissue. A significant correlation between the ratio of PPARgamma2 mRNA to total PPARgamma mRNA and obesity was observed, whereas total PPARgamma mRNA levels showed no significant relationships to obesity. There was also a significant relationship between the ratio of PPARgamma2 mRNA to total PPARgamma mRNA and fasting plasma insulin concentration. The mRNA levels of C/EBPalpha, LPL and GLUT4 were highly correlated to that of total PPARgamma mRNA. They were also significantly correlated to the mRNA levels of PPARgamma1 and PPARgamma2.The ratio of PPARgamma2 mRNA to total PPARgamma mRNA is related to obesity in the rhesus monkey and mRNA expression of PPARgamma1, PPARgamma2, C/EBPalpha, LPL and GLUT4 appear to be coordinated in vivo.

A quantitative study of the effect of carnitine deficiency on expression of glycolytic and gluconeogenic enzymes was performed using juvenile visceral steatosis mice which are systemically deficient in carnitine. The amounts of glucokinase and L-type pyruvate kinase mRNA were reduced in homozygotes, compared to heterozygotes and normal controls at 2 and 8 weeks. Liver-type phosphofructokinase, however, did not differ significantly. The abundance of fructose 1,6-bisphosphatase mRNA was unchanged at 2 and 8 weeks. The level of phosphoenolpyruvate carboxykinase mRNA was increased slightly at 2 weeks, but not at 8 weeks. A part of these changes could not be explained by the plasma glucose or insulin level. Carnitine administration restored the mRNA of these enzymes to normal levels. These results suggest that carnitine deficiency affects the expression of these liver enzymes.

We conducted a quantitative study of the effect of carnitine deficiency on the mRNA level of carnitine palmitoyltransferase II in the liver, muscle and heart of mice with juvenile visceral steatosis, a strain that is systematically deficient in carnitine. The amount of carnitine palmitoyltransferase II mRNA was increased in liver and muscle of homozygotes, as compared with heterozygotes and normal controls, at 2, 4, and 8 wk of age. The mRNA levels of this enzyme were normalized after carnitine administration. The mRNA level of carnitine palmitoyltransferase II in the heart was increased only at 8 wk, and was not affected by carnitine administration. These results suggest that carnitine displays some effect on the mRNA level of the carnitine palmitoyltransferase II gene in liver and muscle, probably through fatty acid metabolic change.

We have recently shown that three types (A, B, and C) of mRNA species are transcribed from a single gene encoding human muscle phosphofructokinase(hPFK-M) through alternative splicing [Nakajima et al., Biochem. Biophys. Res. Commun. 166 (1990) 637–641]. To determine its complete structure and elucidate the mechanism of alternative RNA splicing, we isolated the hPFK-M gene, which spans about 30 kb, and contains 24 exons. Transcription start points were observed for both exon 1 and cxon 2 by S1 nuclcase protection assay and primer extension. Motifs of an Sp1-binding site were observed in the upstream region of exon 1 (promoter 1). A TATA-box-like sequence and a CAAT-box-like sequence were identified in the upstream region of exon 2 (promoter 2). Reporter assay revealed that the promoter 1 region was functional both in HeLa cells and myoblastic clonal cells, and that the promoter 2 region was active only in myoblastic cells. Motifs of M-CAT known as a muscle-specific enhancer, were observed in the promoter 2 region. These results indicated that the hPFK-M gene contains at least two promoter regions, facilitating the expression of the heterogeneous gene transcripts in a cell-type-specific manner.

Myogenic hyperuricemia is a common pathophysiologic feature of muscle glycogenoses1. Type VII glycogenosis is the one which lacks catalytic activity of phosphofructokinase, a key enzyme of glycolysis, in muscle (PFK-M)2. Energy crisis in the exercising muscles of the patient results in the abnormal purine degradation leading to a typical manifestation of myogenic hyperuricemia1,3. As a step to clarify the molecular basis of this abnormal purine metabolism, we have reported the cloning of full-length human PFK-M cDNA4. The sequence data enabled us to reconfirm the gene duplication mechanism as hypothesized in rabbit PFK-M gene5,6,7. We have also elucidated the existence of the alternative splicing and the alternative promoter system of human PFK-M gene8,9. In addition, we have recently reported the complete structure of human PFK-M gene10. In this paper, we report on the genetic defect in a patient with PFK-M deficiency as the typical clinical entity presenting myogenic hyperuricemia.

'~JE agree that the change in mRNA levels of PPAR-y and VV other genes may be in some part due to changes in hor­ mones, paracrine factors, and nutritionalstatus with aging, It is, however, noteworthy that the decline in thesegene expression lev­ els occurred veryearly, beforeobesity and type 2 diabetes became overt. Thus,it appearsthat theyare,at leastin part, relatively inde­ pendentof such hormones. The mRNA levelsdid not reflectthe functional activity. It is interesting that CIEBPB mRNA did not significantly changewith aging, althoughthe transcriptional cas­ cade beyondCIEBPB declined with age. It is, however, possible that CIEBPB regulates the coordinated decrease of PPAR-y, CIEBPo: and ADDl. We concur that pharmacologicalinterven­ tions will assistin dissecting the interactions of these age-related changesand theirpotential for intervention to improve function.

The anomeric form of glucose produced by glucose-6-phosphatase was studied using an apparatus that specifically measures beta-D-glucose. The time course of beta-D-glucose formation from glucose-6-P by glucose-6-phosphatase is essentially linear. In the presence of mutarotase, this rate is reduced to 70% of that obtained in the absence of mutarotase. When detergent treated microsomes were used, the rate of beta-D-glucose formation is unaffected by mutarotase. These results suggest that only beta-anomer of glucose is produced by microsomal glucose-6-phosphatase and this specificity is determined by translocase for glucose-6-P or glucose. It was also demonstrated that alpha-D-glucose is the substrate for glucokinase.

Variations in the fat-mass and obesity-associated gene (FTO) are associated with the obesity phenotype in many Caucasian populations. This association with the obesity phenotype is not clear in the Japanese. To investigate the relationship between the FTO gene and obesity in the Japanese, we genotyped single nucleotide polymorphisms (SNPs) in the FTO genes from severely obese subjects [n = 927, body mass index (BMI) ≥ 30 kg/m2] and normal-weight control subjects (n = 1,527, BMI

Background Genetic factors as well as environmental factors are important in the development of NAFLD and in this study we investigated associations between polymorphisms of peroxisome proliferators-activated receptor γ coactivator 1α polymorphism (PPARGC1A) and NAFLD. Aims We recruited 115 patients with biopsy-proven NAFLD, 65 with NASH and 50 with simple steatosis, and 441 healthy control subjects and investigated 15 SNPs of PPARGC1A. Results SNP rs2290602 had the lowest p value in the dominant mode (p = 0.00095), and the odds ratio for NAFLD (95% CI) was 2.73 (1.48 – 5.06). rs2290602 was significantly associated with NAFLD even when the most conservative Bonferroni's correction was applied (p = 0.0143). The frequency of the T allele of rs2290602 was significantly higher in the NASH patients than in the control subjects (p = 0.00093, allele frequency mode), and its frequency in the NASH patients tended to be higher than in the simple steatosis patients (p = 0.09). The results of the real-time RT-PCR study showed that intrahepatic mRNA expression of PPARGC1A was lower in the TT group than in the GG or GT group at SNP rs2290602 (p = 0.0454). Conclusion This is the first study to demonstrate a significant association between genetic variations in PPARGC1A and NAFLD. This finding suggested that PPARGC1A polymorphism and lower expression of PPARGC1A mRNA in the liver are an important genetic contribution to etiology of NAFLD.

Visceral fat accumulation contributes to the development of metabolic syndrome. As visceral fat accumulation increases, adiponectin levels decrease; therefore, adiponectin provides a link between visceral fat accumulation and metabolic disorders. Genome-wide association studies (GWASs) have identified genetic variations in the cadherin 13 (CDH13) gene that are associated with adiponectin levels.We investigated whether single nucleotide polymorphisms (SNPs) in CDH13 was associated with adiponectin levels and metabolic syndrome traits independent of the visceral fat area (VFA), as measured using computed tomography (CT) in 945 Japanese individuals.We found that three CDH13 SNPs reported by recent GWASs (i.e., rs3865188, rs4783244, and rs12051272) were significantly associated with higher adiponectin levels (P ＜ 1 × 10 (-14)), even after adjustment for VFA. However, these adiponectin-inducing alleles of CDH13 SNPs were significantly associated with traits consistent with deteriorating metabolic symptoms, such as higher fasting insulin, homeostasis model assessment-insulin resistance (HOMA-IR) scores, and triglycerides and lower high-density lipoprotein (HDL)-cholesterol levels, similar to increasing VFA and decreasing adiponectin levels.These results suggested that CDH13 SNPs cause an adiponectin-resistant status to compensate for increasing adiponectin levels and could result in the deterioration of metabolic syndrome traits.

Background In a genome-wide association scan, the single-nucleotide polymorphism (SNP) rs738409 in the patatin-like phospholipase 3 gene (PNPLA3) was strongly associated with increased liver fat content. We investigated whether this SNP is associated with the occurrence and progression of nonalcoholic fatty liver disease (NAFLD) in the Japanese population. Methods SNP rs738409 was genotyped by the Taqman assay in 253 patients with NAFLD (189 with nonalcoholic steatohepatitis [NASH] and 64 with simple steatosis) and 578 control subjects. All patients with NAFLD underwent liver biopsy. Control subjects had no metabolic disorders. For a case-control study, the χ2-test (additive model) was performed. Odds ratios (ORs) were adjusted for age, gender, and body mass index (BMI) by using multiple logistic regression analysis with genotypes (additive model), age, gender, and BMI as the independent variables. Multiple linear regression analysis was performed to test the independent effect of risk allele on clinical parameters while considering the effects of other variables (age, gender, and BMI), which were assumed to be independent of the effect of the SNP. Results The risk allele (G-allele) frequency of rs738409 was 0.44 in the control subjects and 0.60 in patients with NAFLD; this shows a strong association with NAFLD (additive model, P = 9.4 × 10-10). The OR (95% confidence interval) adjusted for age, gender, and BMI was 1.73 (1.25-2.38). Multiple linear regression analysis indicated that the G-allele of rs738409 was significantly associated with increases in aspartate transaminase (AST) (P = 0.00013), alanine transaminase (ALT) (P = 9.1 × 10-6), and ferritin levels (P = 0.014), and the fibrosis stage (P = 0.011) in the patients with NAFLD, even after adjustment for age, gender, and BMI. The steatosis grade was not associated with rs738409. Conclusions We found that in the Japanese population, individuals harboring the G-allele of rs738409 were susceptible to NAFLD, and that rs738409 was associated with plasma levels of ALT, AST, and ferritin, and the histological fibrosis stage. Our study suggests that PNPLA3 may be involved in the progression of fibrosis in NAFLD.

Bombesin receptor subtype-3 (BRS-3) is one of the candidate genes of obesity. The mice lacking BRS-3 have been shown to develop mild obesity. These mice also showed hypertension and impaired glucose metabolism, supporting these mice as a good model for human obesity. We screened 104 Japanese obese men (BMI > 26.4, 26.5-44.1) to investigate whether there is any genetic defect in BRS-3 gene. The DNA fragments containing each exon of BRS-3 gene were amplified by polymerase chain reaction (PCR) and were directly sequenced. No mutation, nor polymorphism was found in the coding region of BRS-3, suggesting that mutation of this gene is not a major cause of obesity in humans.