UCP2 A55V variant is associated with obesity and related phenotypes in an aboriginal community in Taiwan

ACOT1 deficiency attenuates high-fat diet-induced fat mass gain by increasing energy expenditure

Acyl-CoA thioesterase 1 (ACOT1) catalyzes the hydrolysis of long-chain acyl-CoAs to free fatty acids and CoA and is typically upregulated in obesity. Whether targeting ACOT1 in the setting of high-fat diet-induced (HFD-induced) obesity would be metabolically beneficial is not known. Here we report that male and female ACOT1KO mice are partially protected from HFD-induced obesity, an effect associated with increased energy expenditure without alterations in physical activity or food intake. In males, ACOT1 deficiency increased mitochondrial uncoupling protein-2 (UCP2) protein abundance while reducing 4-hydroxynonenal, a marker of oxidative stress, in white adipose tissue and liver of HFD-fed mice. Moreover, concurrent knockdown (KD) of UCP2 with ACOT1 in hepatocytes prevented increases in oxygen consumption observed with ACOT1 KD during high lipid loading, suggesting that UCP2-induced uncoupling may increase energy expenditure to attenuate weight gain. Together, these data indicate that targeting ACOT1 may be effective for obesity prevention during caloric excess by increasing energy expenditure.

Ethnic disparity in metabolic syndrome and related obesity and health behavior: a community study in Taiwan

BACKGROUND

As studies on ethnic disparities in metabolic syndrome and its risk factors in Taiwan are still rare, the aims of this study were: (1) to detect the differences in the rates of metabolic syndrome, obesity and health behaviors between two ethnic groups (indigenous Tsou and nonindigenous Han) living in the same area and with similar age and sex distributions; (2) to examine whether ethnicity per se plays a significant role in the occurrence of metabolic syndrome, while taking other risk factors including sociodemographic characteristics, obesity and health behaviors into consideration.

METHODS

This is a cross-sectional study using data from a community survey conducted in Chiayi County in southwestern Taiwan. A frequency matching strategy by age and sex with a ratio of 1 (Tsou) to 3 (Han) was applied to select a comparable sample between both ethnic groups (667 Tsou and 2001 Han) from among the survey participants. Furthermore, participants with cardiometabolic diseases diagnosed before the surveyed day were excluded to avoid confounding any associated risk factors for developing metabolic syndrome (MS). A final analytic sample of 1482 remained. The used information included sociodemographic characteristics, medical histories, health behaviors, and the concentrations of triglycerides, cholesterol, and glucose.

RESULTS

Indigenous Tsou had significantly higher rates of metabolic syndromes, obesity and unhealthy behaviors than their Han counterparts (MS: 54.0% vs. 29.1%, obesity: 54.0% vs. 23.2%, drinking alcohol: 17.5% vs. 13.6%, and higher intake of fried food: 6.4% vs. 4.4%), even though they were similar in age and sex distributions. The significant risk factors for subsequently developing MS included being indigenous Tsou (adjusted POR = 2.62, P < 0.001), older, single, and obese. Stratified analyses on the risk factors for developing MS by health behaviors and by obese problems also indicated increased risks of being indigenous Tsou.

CONCLUSIONS

There existed ethnic differences in the rates of metabolic syndrome, obesity, and health behaviors. Ethnicity per se did play a significant role in developing MS; in particular indigenous Tsou people had increased risks, suggesting possible biological reasons rooted in their origins that need further exploration. In addition, unhealthy behaviors may potentially have an indirect effect on developing MS via their effect on obesity.

Unleash the Association of Mitochondrial Uncoupling Protein (UCP2) Promoter Variant (G-866A; rs659366) with Obesity: Stepping from a Case-Control Study to a Meta-analysis

Numerous eligible articles investigated the potential impact of the promoter region of UCP2 (rs659366) variant and the susceptibility for obesity with questionable outcomes. Our team designed this case-control combined with meta-analysis survey to illustrate the contribution of this variant with obesity. This case-control survey was formulated based on 110 obese Egyptian patients and 122 non-obese controls. Genomic DNA was amplified for ascertaining of UCP2 (G-866A; rs659366) variant exploiting the PCR-RFLP technique. A literature search was completed to investigate the involvement of this variant with obesity from various genetic databases. In this case-control study, the distribution of UCP2 (rs659366) variant showed a significant association with obesity among Egyptian subjects under allelic and dominant models (P value = 0.0006 and < 0.001, respectively). Overall, twenty-five comparisons for this variant (8652 obese patients and 10,075 non-obese controls) were recruited in this meta-analysis survey. A noteworthy association of UCP2 (rs659366) variant with obesity was identified among Asians and Africans but not Caucasians under allelic, dominant as well as heterozygote models. Nevertheless, this meta-analysis could not accomplish a noticeable association with overall subjects under different genetic models. This case-controlled study revealed a robust association for UCP2 (rs659366) variant with obesity susceptibility in Egyptian subjects; however, this meta-analysis survey failed to achieve an association for this variant with obesity in overall subjects except among Asians and Africans.

Genetically driven antioxidant capacity in a Caucasian Southeastern European population

Previous studies have underlined the function of specific xenobiotic metabolizing phase-I or phase-II enzymes and endogenous antioxidant-related enzymes in the reduction and/or progression of oxidative stress and consequently the incidence of several diseases. In the present study, 10 polymorphic variants (rs4880, rs1799895, rs660339, rs1050450, rs1001179, rs28665122, rs1695, rs1138272, rs1051740 and rs2234922) were investigated in 1132 individuals of a Caucasian Southeastern European population. The frequency distribution of alleles and genotypes was compared to data of European (Northern, Central, Northwestern and Southwestern) and Global populations, extracted from the ensembl genome browser. The allele frequencies in the case of rs1051740 were similar to the frequencies noted in the global population. The majority of the present study allelic polymorphisms showed similar frequency distribution to those of the European or the Global populations (0.88≤OR≤1.14). The rs1051740 polymorphism demonstrated similar to the Global population frequencies (OR=1.09). In conclusion, observed distributions of the polymorphisms studied in the Southeastern population demonstrate a positive impact (rs4880, rs1799895, rs660339, rs28665122) and a negative impact (rs1050450, rs1138272, rs109179, rs1695) against oxidative stress when compared to other population groups.

Interactions between UCP2 SNPs and telomere length exist in the absence of diabetes or pre-diabetes

Mitochondrial uncoupling protein 2 (UCP2) can affect oxidative stress levels. UCP2 polymorphisms are associated with leukocyte telomere length (LTL) in Type 2 Diabetes, which also induces considerable background oxidative stress. The effects of UCP2 polymorphisms on LTL in populations without diabetes have not been well described. Our aims are to evaluate the interaction between LTL and UCP2 polymorphisms in 950 subjects without diabetes. The monochrome multiplex quantitative PCR method was used to measure relative LTL. Taqman SNP genotyping assay was applied to genotypes for UCP2 rs659366 and rs660339. We found shorter LTL associated with increased age (P < 0.001) and triglyceride levels (P = 0.041). After adjustment for cardiovascular risk factors, rs659336 GG genotype carriers demonstrated a shorter LTL (1.257 ± 0.186), compared to GA carriers (1.288 ± 0.230, P = 0.022) and AA carriers (1.314 ± 0.253, P = 0.002). LTL was shorter in the CC rs660339 genotype (1.254 ± 0.187) compared to TT (1.297 ± 0.242, P = 0.007) and CT carriers (1.292 ± 0.229, P = 0.016). The T allele of rs660339 is associated with a longer LTL of approximately 0.04 compared to CC homozygotes. Thus, UCP2 rs659366 A allele and rs660339 T allele are both related to longer LTL in subjects without diabetes, independent of cardiovascular risk factors.

Ethnic Disparities in Blood Pressure: A Population-based Study

Taiwan's indigenous population exhibits a higher mortality of cardiovascular disease, but current research has not reported any associations among ethnicities on the blood pressure (BP). We randomly selected representative samples in this population-based study. We measured height, weight, hip and waist circumferences, and blood pressure in a screening survey. Systolic BP and diastolic BP were significantly higher in the indigenous population. Among women, prevalence rates of DBP > 90 mmHg among indigenes (32.9 %) were significantly high than those in Han Chinese (17.4 %). Based on multivariate analysis adjusted for covariates, the results showed gender and ethnicity to be significantly correlated with systolic and diastolic BP. Gender was a modifier between ethnicity and BP. Furthermore, we found an additive effect between ethnicity and age on systolic and diastolic BP by gender. Our study showed independent additive effects on systolic BP and diastolic BP between ethnicity and age by gender.

Association of the UCP polymorphisms with susceptibility to obesity: case-control study and meta-analysis

This paper describes a case-control study and a meta-analysis performed to evaluate if the following polymorphisms are associated with presence of obesity: -3826A/G (UCP1); -866G/A, Ala55Val and Ins/Del (UCP2) and -55C/T (UCP3). The case-control study enrolled 282 obese and 483 non-obese patients with type 2 diabetes. A literature search was made to identify all studies that evaluated associations between UCP1-3 polymorphisms and obesity. In the case-control study the distributions of the UCP variants did not differ between obese and non-obese groups (P > 0.05). Forty-seven studies were eligible for the meta-analysis and the results showed that the UCP2 -866G/A and UCP3 -55C/T polymorphisms were associated with protection to obesity in Europeans (OR = 0.89, 95% CI 0.82-0.97 and OR = 0.88, 95% CI 0.80-0.97, respectively). The UCP2 Ala55 val polymorphism was associated with obesity in Asians (OR = 1.61, 95% CI 1.13-2.30). The UCP2 Ins/Del polymorphism was associated with obesity mainly in Europeans (OR = 1.19, 95% CI 1.00-1.42). There was no significant association of the UCP1 -3826A/G polymorphism with obesity. In our case-control study we were not able to demonstrate any association between UCP polymorphisms and obesity in T2DM patients; however, in the meta-analysis we detected a significant association of UCP2 -866G/A, Ins/Del, Ala55Val and UCP3 -55C/T polymorphisms with obesity.

Uncoupling protein 2 gene polymorphisms in association with overweight and obesity susceptibility: A meta-analysis

A meta-analysis was performed to evaluate the associations of uncoupling protein 2 (UCP2) gene polymorphisms (Ala55Val, 45-bp insertion/deletion, and -866G/A) with overweight and obesity. A total of 42 studies were included in our analysis. Pooled effect estimates and 95% confidential intervals of each polymorphism were calculated under different inherited models. Fixed or random effect model was selected based on the between-study heterogeneity evaluated with I². Source of heterogeneity was explored by subgroup analysis and meta-regression analysis. Potential publication bias was assessed using funnel plot and Peters test. After excluding studies that deviated from the Hardy–Weinberg equilibrium, T allele of Ala55Val polymorphism was associated with an increased risk of overweight and obesity under recessive model in the overall (OR = 1.24, 95%CI = 1.06–1.45) and Asian (OR = 1.28, 95%CI = 1.06–1.55) populations; and A allele of -866G/A polymorphism had a protective effect on overweight and obesity, especially for European populations (dominant model: OR = 0.88, 95%CI = 0.81–0.96, co-dominant 1 model: OR = 0.89, 95%CI = 0.81–0.98, co-dominant 2 model: OR = 0.85, 95%CI = 0.74–0.94, additive model: OR = 0.88, 95%CI = 0.80–0.95, and allelic model: OR = 0.91, 95%CI = 0.86–0.97). No evidence was observed in the association of 45-bp insertion/deletion polymorphism with overweight and obesity susceptibility. We failed to fully explore the between-study heterogeneity regarding the association of Ala55Val polymorphism with overweight and obesity. Further studies are required to provide more convincing evidence.

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We evaluated the association of UCP2 gene polymorphisms with overweight and obesity.

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Ala55Val polymorphism was associated with an increased risk in Asian populations.

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No association was observed for 45-bp insertion/deletion polymorphism.

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-866G/A polymorphism was associated with a decreased risk in European populations.

WITHDRAWN: Uncoupling protein 2 gene polymorphisms in association with overweight and obesity susceptibility: A meta-analysis

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

UCP2 -866G/A, Ala55Val and UCP3 -55C/T polymorphisms in association with obesity susceptibility - a meta-analysis study

AIMS/HYPOTHESIS

Variants of UCP2 and UCP3 genes have been reported to be associated with obesity, but the available data on the relationship are inconsistent. A meta-analysis was performed to determine whether there are any associations between the UCP2 -866G/A, Ala55Val, and UCP3 -55C/T polymorphisms and obesity susceptibility.

METHODS

The PubMed, Embase, Web of Science and CNKI, CBMdisc databases were searched for all relevant case-control studies. The fixed or random effect pooled measure was determined on the bias of heterogeneity test among studies. Publication bias was examined by the modified Begg's and Egger's test.

RESULTS

Twenty-two published articles with thirty-two outcomes were included in the meta-analysis: 12 studies with a total of 7,390 cases and 9,860 controls were analyzed for UCP2 -866G/A polymorphism with obesity, 9 studies with 1,483 cases and 2,067 controls for UCP2 Ala55Val and 8 studies with 2,180 cases and 2,514 controls for UCP3 -55C/T polymorphism. Using an additive model, the UCP2 -866G/A polymorphism showed no significant association with obesity risk in Asians (REM OR = 0.81, 95% CI: 0.65-1.01). In contrast, a statistically significant association was observed in subjects of European descent (FEM OR = 1.06, 95% CI: 1.01-1.12). But neither the UCP2 Ala55Val nor the UCP3 -55C/T polymorphism showed any significant association with obesity risk in either subjects of Asian (REM OR = 0.84, 95% CI: 0.67-1.06 for Ala55Val; REM OR = 0.94, 95% CI: 0.55-1.28 for -55C/T) or of European descent (REM OR = 1.04, 95% CI: 0.80-1.36 for Ala55Val; FEM OR = 1.08, 95% CI: 0.97-1.20 for -55C/T).

CONCLUSIONS AND INTERPRETATION

Our meta-analysis revealed that the UCP2 -866G/A polymorphism may be a risk factor for susceptibility to obesity in subjects of European descent, but not in individuals of Asian descent. And our results did not support the association between UCP2 Ala55Val, UCP3 -55C/T polymorphisms and obesity in the populations investigated. This conclusion warrants confirmation by further studies.

Uncoupling protein 2 gene polymorphisms are associated with obesity

Background

Uncoupling protein 2 (UCP2) gene polymorphisms have been reported as genetic risk factors for obesity and type 2 diabetes mellitus (T2DM). We examined the association of commonly observed UCP2 G(−866)A (rs659366) and Ala55Val (C > T) (rs660339) single nucleotide polymorphisms (SNPs) with obesity, high fasting plasma glucose, and serum lipids in a Balinese population.

Methods

A total of 603 participants (278 urban and 325 rural subjects) were recruited from Bali Island, Indonesia. Fasting plasma glucose (FPG), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) were measured. Obesity was determined based on WHO classifications for adult Asians. Participants were genotyped for G(−866)A and Ala55Val polymorphisms of the UCP2 gene.

Results

Obesity prevalence was higher in urban subjects (51%) as compared to rural subjects (23%). The genotype, minor allele (MAF), and heterozygosity frequencies were similar between urban and rural subjects for both SNPs. All genotype frequencies were in Hardy-Weinberg equilibrium. A combined analysis of genotypes and environment revealed that the urban subjects carrying the A/A genotype of the G(−866)A SNP have higher BMI than the rural subjects with the same genotype. Since the two SNPs showed strong linkage disequilibrium (D’ = 0.946, r² = 0.657), a haplotype analysis was performed. We found that the AT haplotype was associated with high BMI only when the urban environment was taken into account.

Conclusions

We have demonstrated the importance of environmental settings in studying the influence of the common UCP2 gene polymorphisms in the development of obesity in a Balinese population.

Polymorphisms of the UCP2 gene are associated with body fat distribution and risk of abdominal obesity in Spanish population

BACKGROUND

Increased accumulation of fat results from an imbalance between energy expenditure and intake, being modulated by different environmental and genetic factors. Uncoupling proteins (UCPs) are mitochondrial carrier proteins able to spend energy generating heat. Therefore, variations in these genes are good candidates as potential modulators of body fat accumulation. Our aim was to investigate the possible association of genetic variations of the gene codifying the UCP2 protein with obesity and fat distribution.

DESIGN

We performed a cross-sectional study in 2367 individuals from two population-based studies from different regions of Spain. The Hortega Study included 1436 individuals (693 women) 21-85 years old, and the Pizarra Study included 931 individuals (584 women) 18-65 years old. We evaluated three polymorphisms of the UCP2 gene.

RESULTS

The TT genotype of the rs660339 polymorphism and the AA genotype of the rs659366 polymorphism of the UCP2 gene were significantly associated with higher waist circumference in the Hortega Study. Furthermore, subjects carrying both genotypes (TT+AA) also showed higher central adiposity compared with other genotypes. This association was also present in the Pizarra Study. Moreover, in the pooled population, we found a stronger association with waist circumference. Even, we found association with BMI. Furthermore, rs659366 polymorphism was associated with the risk of abdominal obesity (P= 0·04: OR = 1·3; CI = 1·01-1·67).

CONCLUSIONS

Polymorphisms of the UCP2 gene (rs660339 and rs659366) were associated with central obesity. This study shows association between the UCP2 gene and the susceptibility to obesity and body fat distribution in a south European population.

Adiponectin gene SNP276 variants and central obesity confer risks for hyperglycemia in indigenous Taiwanese

This cross-sectional study analyzed the effects of two single nucleotide polymorphisms (SNP) of the adiponectin gene, SNP45 and SNP276, on hyperglycemia in indigenous Taiwanese, and whether central obesity modulates the effects of these SNPs. Overall, 550 indigenous Taiwanese were recruited for this cross-sectional study. The subjects were categorized into a hyperglycemic group if fasting plasma glucose was > 126 mg/dL (n = 88) or the control group if fasting plasma glucose was < 100 mg/dL (n = 462). The SNP276 TT homozygote carried greater hyperglycemia risk than SNP276 GG [odds ratio (OR) = 2.67, 95% confidence interval (CI) = 1.05-6.78], but not heterozygote (OR = 1.54, 95% CI = 0.95-2.50). SNP45 T > G was not associated with hyperglycemia risk. In multivariate-adjusted modeling, we found a significant relationship between SNP276 T carriers (GT + TT) (OR = 2.06, 95% CI = 1.10-3.88) and central obesity (OR = 4.50, 95% CI = 1.91-10.61) with hyperglycemia. Compared with non-central-obese carriers of SNP276 GG, non-central-obese SNP276 T carriers, and central obese subjects with SNP276 GG and SNP276 T carriers had 5.50, 8.31 and 13.76-fold, respectively, higher risks for hyperglycemia; obese carriers of the T-containing variants experienced a combined risk for hyperglycemia. Furthermore, the hyperglycemic risks were more pronounced in leaner (non-central-obese) individuals carrying the T variant than the central-obese individuals. The adiponectin SNP276 T variant and central obesity had independent and additive effects on hyperglycemia risks. These findings may provide valuable information regarding preventive strategies that might be useful to prevent or treat diabetes and its related complications.

Human uncoupling protein 2 and 3 genes are associated with obesity in Japanese

Human uncoupling proteins (UCPs) are mitochondrial proteins that are involved in the control of energy metabolism and the pathophysiology of obesity. Although there have been several reports on the association between the UCP2/UCP3 locus and the obesity, there have been no haplotype-based case-control studies with gender-specific analysis. The aim of this study was to examine whether there is an association between the UCP2/UCP3 locus and the obesity in the Japanese population when using a single nucleotide polymorphism (SNP)-based and haplotype-based case-control study with gender-specific analysis. We examined a group consisting of 551 subjects, of which 369 were non-obese and 182 were overweight and/or obese. We selected one nonsynonymous SNP (rs660339: Ala55Val) as a genetic marker. Genotyping for all subjects was performed by the TaqMan polymerase chain reaction (PCR) method. Although the overall distributions of genotype and allele were not significantly different between the non-obese and the obese groups, the overall distributions of the genotype were significantly different in men (P = 0.030). In the obese group, male subjects with the Val allele were significantly more frequent in both association studies. There was a significant difference in the overall distribution of the haplotype (UCP3 rs180049, UCP3 rs2075577, UCP2 rs660339) between the weight groups (P = 0.010), and in women, there was a significant difference (P = 0.042) in the overall distribution of the haplotype (UCP3 rs2075577, UCP2 rs660339). Nonsynonymous rs660339 in the human UCP2 gene in men, and the haplotype (UCP3 rs2075577-UCP2 rs660339) in women might be good obesity markers.