Gene by sex interaction for measures of obesity in the framingham heart study

Sex Differences in Obesity and Cognitive Function in Chinese Elderly Patients With Chronic Schizophrenia

BACKGROUND

It is well known that schizophrenia is associated with sex differences. However, no study has explored the sex differences in obesity and cognitive function in elderly Chinese patients with schizophrenia.

OBJECTIVE

This study aimed to compare sex differences in obesity and cognitive function in elderly Chinese individuals with schizophrenia.

METHODS

A total of 304 elderly patients with schizophrenia and 130 sex- and age-matched healthy controls from the community were recruited. Demographic, clinical, and lipid parameters were collected for all subjects. The Montreal Cognitive Assessment (MoCA) was used to assess the global cognitive functions of the participants, while the Positive and Negative Syndrome Scale (PANSS) was used to assess psychopathological symptoms in patients with schizophrenia.

RESULTS

Of the patients with schizophrenia, the prevalence of obesity in men and women was 11.7% (19/163) and 21.3% (30/141), respectively. The score (14.51 ± 6.504) of MOCA in elderly male patients with schizophrenia was significantly higher than that (11.40 ± 6.822) in female patients. There was a positive correlation between the MOCA scores and body mass index (BMI) (r=0.206, p=0.018) in male elderly patients with schizophrenia. Conversely, the MOCA scores of female elderly patients with schizophrenia did not correlate with BMI (p>0.05). However, we found no sex differences in obesity and cognition among control older adults.

CONCLUSIONS

Our findings suggest that there are significant sex differences in obesity and cognitive function in elderly Chinese patients with schizophrenia.

Genome-wide association study of morbid obesity in Han Chinese

BACKGROUND

As obesity is becoming pandemic, morbid obesity (MO), an extreme type of obesity, is an emerging issue worldwide. It is imperative to understand the factors responsible for huge weight gain in certain populations in the modern society. Very few genome-wide association studies (GWAS) have been conducted on MO patients. This study is the first MO-GWAS study in the Han-Chinese population in Asia.

METHODS

We conducted a two-stage GWAS with 1110 MO bariatric patients (body mass index [BMI] ≥ 35 kg/m2) from Min-Sheng General Hospital, Taiwan. The first stage involved 575 patients, and 1729 sex- and age-matched controls from the Taiwan Han Chinese Cell and Genome Bank. In the second stage, another 535 patients from the same hospital were genotyped for 52 single nucleotide polymorphisms (SNPs) discovered in the first stage, and 9145 matched controls from Taiwan Biobank were matched for confirmation analysis.

RESULTS

The results of the joint analysis for the second stage revealed six top ranking SNPs, including rs8050136 (p-value = 7.80 × 10- 10), rs9939609 (p-value = 1.32 × 10- 9), rs1421085 (p-value = 1.54 × 10- 8), rs9941349 (p-value = 9.05 × 10- 8), rs1121980 (p-value = 7.27 × 10- 7), and rs9937354 (p-value = 6.65 × 10- 7), which were all located in FTO gene. Significant associations were also observed between MO and RBFOX1, RP11-638 L3.1, TMTC1, CBLN4, CSMD3, and ERBB4, respectively, using the Bonferroni correction criteria for 52 SNPs (p < 9.6 × 10- 4).

CONCLUSION

The most significantly associated locus of MO in the Han-Chinese population was the well-known FTO gene. These SNPs located in intron 1, may include the leptin receptor modulator. Other significant loci, showing weak associations with MO, also suggested the potential mechanism underlying the disorders with eating behaviors or brain/neural development.

Structural and chemical biology of deacetylases for carbohydrates, proteins, small molecules and histones

Deacetylation is the removal of an acetyl group and occurs on a plethora of targets and for a wide range of biological reasons. Several pathogens deacetylate their surface carbohydrates to evade immune response or to support biofilm formation. Furthermore, dynamic acetylation/deacetylation cycles govern processes from chromatin remodeling to posttranslational modifications that compete with phosphorylation. Acetylation usually occurs on nitrogen and oxygen atoms and are referred to as N- and O-acetylation, respectively. This review discusses the structural prerequisites that enzymes must have to catalyze the deacetylation reaction, and how they adapted by formation of specific substrate and metal binding sites.

Lyplal1 is dispensable for normal fat deposition in mice

Genome-wide association studies (GWAS) have detected association between variants in or near the Lysophospholipase-like 1 (LYPLAL1) locus and metabolic traits, including central obesity, fatty liver and waist-to-hip ratio. LYPLAL1 is also known to be upregulated in the adipose tissue of obese patients. However, the physiological role of LYPLAL1 is not understood. To investigate the function of Lyplal1 in vivo we investigated the phenotype of the Lyplal1^{tm1a(KOMP)Wtsi} homozygous mouse. Body composition was unaltered in Lyplal1 knockout mice as assessed by dual-energy X-ray absorptiometry (DEXA) scanning, both on normal chow and on a high-fat diet. Adipose tissue distribution between visceral and subcutaneous fat depots was unaltered, with no change in adipocyte cell size. The response to both insulin and glucose dosing was normal in Lyplal1^{tm1a(KOMP)Wtsi} homozygous mice, with normal fasting blood glucose concentrations. RNAseq analysis of liver, muscle and adipose tissue confirmed that Lyplal1 expression was ablated with minimal additional changes in gene expression. These results suggest that Lyplal1 is dispensable for normal mouse metabolic physiology and that despite having been maintained through evolution Lyplal1 is not an essential gene, suggesting possible functional redundancy. Further studies will be required to clarify its physiological role.

PPARG-LYPLAL1 Multi-Allelic Combination Associated with Obesity and Overweight in Mexican Adolescent Females

OBJECTIVE

We studied multi-loci variants to identify the contribution of six candidate genes (ADIPOQ, CDH13, LYPLAL1, MC4R, PPARG and PGC1A) in the development of obesity and overweight.

DESIGN

We genotyped 404 chromosomes with eleven SNPs in Mexican female adolescents, who were subdivided into two groups (obesity-overweight and normal-weight) using the World Health Organization parameters. Genomic (800 chromosomes) and ancestral (208 chromosomes) controls were included to reduce the population bias. Anthropometric measurements, biochemical parameters, and caloric intake were obtained only in the groups of Mexican female adolescents.

RESULTS

A positive genotype-phenotype association was found that involves the multi-allelic combination of three risk alleles (one in PPARG and two in LYPLAL1) with obesity and overweight (OR=3.1, P=.010). This combination also exhibited a significant association with waist circumference (P=.030) and triglycerides levels (P=.030). These associations were supported by a logistic regression analysis adjusted for several confounding variables.

CONCLUSIONS

Our data suggest the joint participation of PPARG-LYPLAL1 genes in metabolic disorders development. Hence, these genes could act as potential biomarkers in obesity and overweight. Our findings underscore the complexity of metabolic disorders and provide evidence about the importance of multi-loci analysis to study complex diseases.

Integromic analysis of genetic variation and gene expression identifies networks for cardiovascular disease phenotypes

BACKGROUND

Cardiovascular disease (CVD) reflects a highly coordinated complex of traits. Although genome-wide association studies have reported numerous single nucleotide polymorphisms (SNPs) to be associated with CVD, the role of most of these variants in disease processes remains unknown.

METHODS AND RESULTS

We built a CVD network using 1512 SNPs associated with 21 CVD traits in genome-wide association studies (at P≤5×10(-8)) and cross-linked different traits by virtue of their shared SNP associations. We then explored whole blood gene expression in relation to these SNPs in 5257 participants in the Framingham Heart Study. At a false discovery rate <0.05, we identified 370 cis-expression quantitative trait loci (eQTLs; SNPs associated with altered expression of nearby genes) and 44 trans-eQTLs (SNPs associated with altered expression of remote genes). The eQTL network revealed 13 CVD-related modules. Searching for association of eQTL genes with CVD risk factors (lipids, blood pressure, fasting blood glucose, and body mass index) in the same individuals, we found examples in which the expression of eQTL genes was significantly associated with these CVD phenotypes. In addition, mediation tests suggested that a subset of SNPs previously associated with CVD phenotypes in genome-wide association studies may exert their function by altering expression of eQTL genes (eg, LDLR and PCSK7), which in turn may promote interindividual variation in phenotypes.

CONCLUSIONS

Using a network approach to analyze CVD traits, we identified complex networks of SNP-phenotype and SNP-transcript connections. Integrating the CVD network with phenotypic data, we identified biological pathways that may provide insights into potential drug targets for treatment or prevention of CVD.

Replication of 6 obesity genes in a meta-analysis of genome-wide association studies from diverse ancestries

Obesity is a major public health problem with a significant genetic component. Multiple DNA polymorphisms/genes have been shown to be strongly associated with obesity, typically in populations of European descent. The aim of this study was to verify the extent to which 6 confirmed obesity genes (FTO, CTNNBL1, ADRB2, LEPR, PPARG and UCP2 genes) could be replicated in 8 different samples (n = 11,161) and to explore whether the same genes contribute to obesity-susceptibility in populations of different ancestries (five Caucasian, one Chinese, one African-American and one Hispanic population). GWAS-based data sets with 1000 G imputed variants were tested for association with obesity phenotypes individually in each population, and subsequently combined in a meta-analysis. Multiple variants at the FTO locus showed significant associations with BMI, fat mass (FM) and percentage of body fat (PBF) in meta-analysis. The strongest association was detected at rs7185735 (P-value = 1.01×10(-7) for BMI, 1.80×10(-6) for FM, and 5.29×10(-4) for PBF). Variants at the CTNNBL1, LEPR and PPARG loci demonstrated nominal association with obesity phenotypes (meta-analysis P-values ranging from 1.15×10(-3) to 4.94×10(-2)). There was no evidence of association with variants at ADRB2 and UCP2 genes. When stratified by sex and ethnicity, FTO variants showed sex-specific and ethnic-specific effects on obesity traits. Thus, it is likely that FTO has an important role in the sex- and ethnic-specific risk of obesity. Our data confirmed the role of FTO, CTNNBL1, LEPR and PPARG in obesity predisposition. These findings enhanced our knowledge of genetic associations between these genes and obesity-related phenotypes, and provided further justification for pursuing functional studies of these genes in the pathophysiology of obesity. Sex and ethnic differences in genetic susceptibility across populations of diverse ancestries may contribute to a more targeted prevention and customized treatment of obesity.

Sex- and age-interacting eQTLs in human complex diseases

Many complex human diseases exhibit sex or age differences in gene expression. However, the presence and the extent of genotype-specific variations in gene regulation are largely unknown. Here, we report results of a comprehensive analysis of expression regulation of genetic variation related to 11,672 complex disease-associated SNPs as a function of sex and age in whole-blood-derived RNA from 5254 individuals. At false discovery rate <0.05, we identified 14 sex- and 10 age-interacting expression quantitative trait loci (eQTLs). We show that these eQTLs are also associated with many sex- or age-associated traits. These findings provide important context regarding the regulation of phenotypes by genotype-environment interaction.

Personalized medicine in women's obesity prevention and treatment: implications for research, policy and practice

The prevalence of obesity in America has reached epidemic proportions, and obesity among women is particularly concerning. Severe obesity (body mass index ≥35 kg m(-2) ) is more prevalent in women than men. Further, women have sex-specific risk factors that must be considered when developing preventive and therapeutic interventions. This review presents personalized medicine as a dynamic approach to obesity prevention, management and treatment for women. First, we review obesity as a complex health issue, with contributing sex-specific, demographic, psychosocial, behavioural, environmental, epigenetic and genetic/genomic risk factors. Second, we present personalized medicine as a rapidly advancing field of health care that seeks to quantify these complex risk factors to develop more targeted and effective strategies that can improve disease management and/or better minimize an individual's likelihood of developing obesity. Third, we discuss how personalized medicine can be applied in a clinical setting with current and emerging tools, including health risk assessments, personalized health plans, and strategies for increasing patient engagement. Finally, we discuss the need for additional research, training and policy that can enhance the practice of personalized medicine in women's obesity, including further advancements in the '-omics' sciences, physician training in personalized medicine, and additional development and standardization of innovative targeted therapies and clinical tools.

Sex-specific effects of weight-affecting gene variants in a life course perspective--The HUNT Study, Norway

OBJECTIVE

The impact of previously identified genetic variants directly or indirectly associated with obesity, were investigated at birth, adolescence and adulthood to provide knowledge concerning timing and mechanisms of obesity susceptibility with focus on sex differences.

DESIGN

Twenty four previously identified obesity- and eating disorder susceptibility loci were tested for association with adiposity traits at birth (ponderal index (PI)), adolescence and young adulthood (body mass index (BMI), waist circumference (WC) and waist-hip ratio (WHR)) in 1782 individuals from the HUNT study. Single-nucleotide polymorphism (SNPs) were evaluated individually and by haplotype sliding-window approach for windows50 kb (near-MC4R, FTO and near-BDNF). The analyses were performed on the total and sex stratified samples.

RESULTS

The most substantial effect on BMI was observed for the near-MC4R variants at adolescence and adulthood (adjusted P-values in adolescence: 0.002 and 0.003 for rs17782313 and rs571312, respectively). The same variants showed inverse association with PI in males (adjusted P-values: 0.019-0.036). Furthermore, significant effects were observed at adolescence with BMI for the near-KCTD15 variant (rs11084753) (adjusted P=0.038) in the combined sample. The near-INSIG2 (rs7566605) was significantly associated to WHR in males and near-BDNF (rs925946) in the combined sample (adjusted P=0.027 and P=0.033, respectively). The OPRD1 locus was associated to BMI and WC in males both at adolescence and adulthood with highest effect in adults (adjusted P=0.058). Interaction with sex was identified for near-MC4R, OPRD1, COMT, near-BDNF and DRD2.

CONCLUSIONS

Most obesity susceptibility variants show stronger effect at adolescence than at birth and adulthood with a clear sex-specific effect at some loci. The near-MC4R locus exhibit inverse effect on weight at birth in boys compared with findings at adolescence and adulthood. Some variants less known for obesity-susceptibility such as OPRD1 were found to be associated to weight with strongest effects in males.

Development and evaluation of a genetic risk score for obesity

Multi-locus profiles of genetic risk, so-called "genetic risk scores," can be used to translate discoveries from genome-wide association studies into tools for population health research. We developed a genetic risk score for obesity from results of 16 published genome-wide association studies of obesity phenotypes in European-descent samples. We then evaluated this genetic risk score using data from the Atherosclerosis Risk in Communities (ARIC) cohort GWAS sample (N = 10,745, 55% female, 77% white, 23% African American). Our 32-locus GRS was a statistically significant predictor of body mass index (BMI) and obesity among ARIC whites [for BMI, r = 0.13, p<1 × 10(-30); for obesity, area under the receiver operating characteristic curve (AUC) = 0.57 (95% CI 0.55-0.58)]. The GRS predicted differences in obesity risk net of demographic, geographic, and socioeconomic information. The GRS performed less well among African Americans. The genetic risk score we derived from GWAS provides a molecular measurement of genetic predisposition to elevated BMI and obesity.[Supplemental materials are available for this article. Go to the publisher's online edition of Biodemography and Social Biology for the following resource: Supplement to Development & Evaluation of a Genetic Risk Score for Obesity.].

The genetic contribution to disease risk and variability in response to diet: where is the hidden heritability?

Ten years ago, it was assumed that disease risk prediction and personalised nutrition based on genetic information would now be in widespread use. However, this has not (yet) transpired. The interaction of genetic make-up, diet and health is far more complex and subtle than originally thought. With a few notable exceptions, the impact of identified common genetic variants on phenotype is relatively small and variable in their penetrance. Furthermore, the known variants account for only a fraction of what we believe to be the total genetic contribution to disease risk and heterogeneity in response to environmental change. Here, the question ‘how far have we progressed and are we likely to get there’ (Rimbach and Minihane, 2009) is revisited with regard to the translation of genetic knowledge into public health benefit. It is concluded that progress to date has been modest. It is hoped that recent technological developments allowing the detection of rarer variants and future use of more hypothesis-driven targeted data analysis will reveal most of the currently ‘hidden’ significant genetic variability.

Crystal structure of the predicted phospholipase LYPLAL1 reveals unexpected functional plasticity despite close relationship to acyl protein thioesterases

Sequence homology indicates the existence of three human cytosolic acyl protein thioesterases, including APT1 that is known to depalmitoylate H- and N-Ras. One of them is the lysophospholipase-like 1 (LYPLAL1) protein that on the one hand is predicted to be closely related to APT1 but on the other hand might also function as a potential triacylglycerol lipase involved in obesity. However, its role remained unclear. The 1.7 Å crystal structure of LYPLAL1 reveals a fold very similar to APT1, as expected, but features a shape of the active site that precludes binding of long-chain substrates. Biochemical data demonstrate that LYPLAL1 exhibits neither phospholipase nor triacylglycerol lipase activity, but rather accepts short-chain substrates. Furthermore, extensive screening efforts using chemical array technique revealed a first small molecule inhibitor of LYPLAL1.