Association of ARHGEF11 R1467H polymorphism with risk for type 2 diabetes mellitus and insulin resistance in Chinese population

Genetic Diversity Analysis and Identification of Candidate Genes for Growth Traits in Chengkou Mountain Chicken

Growth traits constitute critical factors in the breeding program of broiler chickens. The Chengkou mountain chicken A-lineage (CMC-A) represents a breed specifically bred for meat production. To further explore the growth performance of the CMC-A population, this study conducted whole-genome sequencing on 464 CMC-A roosters to systematically evaluate their genetic diversity. Additionally, runs of homozygosity (ROH) islands and genome-wide association studies (GWASs) were employed to identify the loci and functional genes influencing the growth traits in Chengkou mountain chickens. The results revealed a high level of genetic diversity and low levels of inbreeding in Chengkou mountain chickens. Several genes associated with stress resistance, muscle growth, and fat deposition were pinpointed through ROH island identification. Moreover, 52 SNP loci were detected, along with 71 candidate genes. These findings enhance our understanding of the genetic architecture underlying the growth traits in Chengkou mountain chickens and provide a theoretical foundation for subsequent breeding endeavors.

Identifying Potential Markers for Monitoring Progression to Ovarian Cancer Using Plasma Label-free Proteomics

Background: Cancer antigen 125 (CA125) is considered to have high sensitivity but poor specificity for ovarian cancer. New biomarkers utilized to early detect and monitor the progression of ovarian cancer patients are critically needed. Methods: A total of 80 patients including 16 early stage, and matched with 17 late stage, 23 benign ovarian tumor (BOT) and 24 uterine fibroid (UF) patients were utilized to perform plasma proteomics analysis using isobaric tag for relative and absolute quantitation (iTRAQ) method to identify differential diagnostic proteins of ovarian cancer patients. A validation set of 9 early stage, 11 late stage, 17 BOT and 16 UF collected by an independent cohort of samples with the same matching principles was examined to confirm the expressed levels of differential expression proteins by ELISA analysis. Results: CRP and ARHGEF 11 were identified as potential diagnostic biomarkers of ovarian cancer. Results of area under the curve (AUC) analysis suggested that combination of diagnostic proteins and CA125 achieved a much higher diagnostic accuracy compared with CA125 alone (AUC values: 0.98 versus 0.80), especially improved the specificity (0.97 versus 0.77). In addition, elevated plasma CRP levels were associated with increased risk of ovarian cancer. Conclusions: Current study found that plasma protein CRP was an indicator for monitoring the progression of ovarian cancer. Combination of plasma protein biomarkers with CA125 could be utilized to early diagnose of ovarian cancer patients.

Epigenetic alteration of Rho guanine nucleotide exchange Factor 11 (ARHGEF11) in cord blood samples in macrosomia exposed to intrauterine hyperglycemia

Background: Macrosomia at birth is associated with maternal hyperglycemia and leads to subsequent susceptibility to obesity, abnormal glucose metabolism, hypertension, and dyslipidemia in offspring. Epigenetic reprogramming has been reported to be involved in the development of human diseases caused by suboptimal environmental or nutritional factors. The study was aiming to explore epigenetic mechanism influences on macrosomic infants exposed to intrauterine hyperglycemia. We performed a genome-wide analysis of DNA methylation in cord blood from macrosomic infants born to women with gestational diabetes in order to identify genes related to fetal growth or early adipose tissue development.Methods: To analyze the epigenetic patterns in umbilical cord blood in gestational diabetes mellitus (GDM), we collected umbilical cord blood from women with GDM (mean pregestational BMI of 24.4 kg/m² and mean neonatal birth weight of 4366 g) and normal glucose-tolerant women (mean pregestational BMI of 19.8 kg/m² and mean neonatal birth weight of 3166 g). Differentially methylated genes in the GDM group were identified using the Infinium HumanMethylation450 BeadChip array.Results: A total of 1251 genes were differentially methylated compared to the controls (p < .01). The methylation microarray data showed that two specific CpG sites (cg12604331 and cg08480098) in the gene body of ARHGEF11 were significantly hypomethylated in the cord blood in macrosomic infants. Altered DNA methylation levels of ARHGEF11 were negatively correlated with glucose levels and neonatal birth weight.Conclusions: Exposure to adverse intrauterine environments can alter fetal development, such as by affecting the nutritional status of the fetus. Such exposure can also result in significant epigenetic modifications, including DNA methylation, which could serve as a potential marker for nutrition and metabolic conditions at the neonatal stage or even in the adult.

Transgenerational Obesity and Alteration of ARHGEF11 in the Rat Liver Induced by Intrauterine Hyperglycemia

It is understood that intrauterine hyperglycemia increases the risk of obesity and diabetes in offspring of consecutive generations but its mechanisms remain obscure. This study is aimed at establishing an intrauterine hyperglycemia rat model to investigate the growth and glycolipid metabolic characteristics in transgenerational offspring and discuss the effects of Rho guanine nucleotide exchange factor 11 (ARHGEF11) and the PI3K/AKT signaling pathway in offspring development. The severe intrauterine hyperglycemia rat model was caused by STZ injection before mating, while offspring development and glycolipid metabolism were observed for the following two generations. The expression of ARHGEF11, ROCK1, PI3K, and AKT was tested in the liver and muscle tissue of F2 offspring. The results showed severe growth restriction in F1 offspring and obesity, fatty liver, and insulin resistance in female F2 offspring, especially the offspring of female intrauterine hyperglycemia-exposed parents (F2G♀C♂) and both (F2G♀G♂). The expression of ARHGEF11 and ROCK1 was significantly elevated; PI3K and phosphorylation of AKT were significantly decreased in liver tissues of F2G♀C♂ and F2G♀G♂. Our study revealed that intrauterine hyperglycemia could cause obesity and abnormal glycolipid metabolism in female transgenerational offspring; the programming effect of the intrauterine environment could cause a more obvious phenotype in the maternal line. Further exploration suggested that increased expression of ARHGEF11 and ROCK1 and the decreased expression of PI3K and phosphorylation of AKT in the liver could be responsible for the abnormal development in F2 offspring.

Higher mortality and years of potential life lost of suicide in patients with schizophrenia

Patients with schizophrenia could have a higher risk of mortality. We compared the risk of mortality and the years of potential life lost (YPLL) associated with various causes of death between patients with schizophrenia and the general population. A total of 4,298 patients with schizophrenia were included. The cohort was linked to the Taiwan Death Register between 1998 and 2010 using personal identification numbers, which showed 367 patients with schizophrenia had died by the end of 2010. The standard mortality ratios (SMRs) and YPLL were analyzed by age, sex and cause of death. The overall SMR was significantly higher in patients with schizophrenia. Suicide had the most significantly greater SMR, and the SMRs for physical illnesses, accidents and injuries were all significantly greater in patients with schizophrenia. Suicide had the largest YPLL/deaths among all causes of mortality in patients with schizophrenia. Suicide had the most significantly greater risk of mortality among patients with schizophrenia as compared with the general population. Patients with schizophrenia are highly vulnerable in terms of increased mortality and require special attention.

Comparative gene expression profile and DNA methylation status in diabetic patients of Kazak and Han people

We attempted to investigate the mechanism and susceptibility genes for diabetes in Han and Kazak ethnic individuals.The abdominal omental adipose tissues were obtained from diabetic cases and healthy controls. The gene expression and methylation data were produced for Kazak and Han individuals, respectively, and analyzed by bioinformatics analysis.We obtained 921 differentially expressed genes (DEGs) in Han group and 1772 in Kazak group. DEGs in Han group were significantly related with type 2 diabetes mellitus, and biosynthesis of amino acids, while the DEGs specific to Kazak patients were significantly enriched in metabolism-related pathways such as carbon metabolism, propanoate metabolism, and 2-oxocarboxylic acid metabolism. Major facilitator superfamily domain containing 1 (MFSD1) was found to be a methylation associated gene at hypermethylation site of cg16289538 in Han group. Rho guanine nucleotide exchange factor 1 (ARHGEF1) was the susceptible gene corresponding to the methylation sites of cg18800192 and cg00759295 in Kazak group. ARHGEF1 was also a node in protein-protein interaction network and significantly enriched in hsa04270: vascular smooth muscle contraction pathways.The molecular mechanism of diabetes may be different in Han and Kazak patients. MFSD1 and ARHGEF1 may be the diabetes susceptible genes.

Calcineurin is an important factor involved in glucose uptake in human adipocytes

Calcineurin inhibitors are used in immunosuppressive therapy applied after transplantation, but they are associated with major metabolic side effects including the development of new onset diabetes. Previously, we have shown that the calcineurin inhibiting drugs tacrolimus and cyclosporin A reduce adipocyte and myocyte glucose uptakes by reducing the amount of glucose transporter type 4 (GLUT4) at the cell surface, due to an increased internalization rate. However, this happens without alteration in total protein and phosphorylation levels of key proteins involved in insulin signalling or in the total amount of GLUT4. The present study evaluates possible pathways involved in the altered internalization of GLUT4 and consequent reduction of glucose uptake provoked by calcineurin inhibitors in human subcutaneous adipose tissue. Short- and long-term treatments with tacrolimus, cyclosporin A or another CNI deltamethrin (herbicide) decreased basal and insulin-dependent glucose uptake in adipocytes, without any additive effects observed when added together. However, no tacrolimus effects were observed on glucose uptake when gene transcription and protein translation were inhibited. Investigation of genes potentially involved in GLUT4 trafficking showed only a small effect on ARHGEF11 gene expression (p < 0.05). In conlusion, the specific inhibition of calcineurin, but not that of protein phosphatases, decreases glucose uptake in human subcutaneous adipocytes, suggesting that calcineurin is an important regulator of glucose transport. This inhibitory effect is mediated via gene transcription or protein translation; however, expression of genes potentially involved in GLUT4 trafficking and endocytosis appears not to be involved in these effects.

Genetic variants and clinical relevance associated with gestational diabetes mellitus in Chinese women: a case-control study

PURPOSE

Gestational diabetes mellitus (GDM) may share similar mechanisms with type 2 diabetes and obesity. In the current study, we aimed to verify twenty genes reported to be associated with type 2 diabetes and obesity in the Chinese GDM population.

METHODS

Pregnant women aged 20-49 years at 24-28 gestational weeks were recruited and 556 cases and 445 controls were enrolled in the study. The genotyping of single nucleotide polymorphisms (SNPs) was performed on peripheral blood samples.

RESULTS

We discovered that GDM was associated with rs945508 (OR = 1.368, 95% CI = 1.080-1.732, p = .009), rs10804591 (OR = 1.446, 95% CI = 1.192-1.754, p < .001), rs10245353 (OR = 1.204, 95% CI = 1.006-1.441, p = .043) and rs1552224 (OR = 1.451, 95% CI = 1.071-1.964, p = .016).

CONCLUSIONS

We found that four SNPs associated with type 2 diabetes and obesity may also increase the risk of developing GDM in the Chinese population. Among these SNPs, we report for the first time that rs945508 in ARHGEF11, rs10804591 in PLXND1 and rs10245353 in NFE2L3 were associated with GDM.

Human Rho Guanine Nucleotide Exchange Factor 11 (ARHGEF11) Regulates Dendritic Morphogenesis

Disturbances of synaptic connectivity during perinatal and adolescent periods have been hypothesized to be related to the pathophysiology of schizophrenia. Rho guanine nucleotide exchange factor 11 (ARHGEF11) is a specific guanine nucleotide exchange factors (GEF) for RhoA, which is a critical regulator of actin cytoskeleton dynamics and organization of dendritic spines and inhibitor of spine maintenance. ARHGEF11 variants are reported to be associated with a higher risk for the onset of schizophrenia in a Japanese population; however, how ARHGEF11 contributes to the pathogenesis of schizophrenia in dendritic spines is unknown. Therefore, we first studied the distribution, binding, and function of ARHGEF11 in the dendritic spines of the rat cerebral cortex. After subcellular fractionation of the rat cerebral cortex, ARHGEF11 was detected with synaptophysin and post-synaptic density protein 95 (PSD-95) in the P2 fractions including synaptosomal fractions containing presynaptic and postsynaptic density proteins. Endogenous ARHGEF11 was coimmunoprecipitated with synaptophysin or PSD-95. In cortical primary neurons at 28 days in vitro, immunostaining revealed that ARHGEF11 located in the dendrites and dendritic spines and colocalized with PSD-95 and synaptophysin. Overexpression of exogenous ARHGEF11 significantly decreased the number of spines (p = 0.008). These results indicate that ARHGEF11 is likely to be associated with synaptic membranes and regulation of spine.

Comparative proteomics of umbilical vein blood plasma from normal and gestational diabetes mellitus patients reveals differentially expressed proteins associated with childhood obesity

PURPOSE

Offspring obesity is one of long-term complications of gestational diabetes mellitus (GDM). The aim of this study is to identify proteins differentially expressed in the umbilical vein blood plasma, which could become markers for early diagnosis of childhood obesity.

EXPERIMENTAL DESIGN

Umbilical vein plasma samples were collected from 30 control and 30 GDM patients in 2007-2008 whose offspring were suffering from obesity at 6-7 years old. Multiplexed isobaric tandem mass tag labeling combined with LC-MS/MS was used to identify differentially expressed proteins. Ingenuity pathway analysis was performed to identify canonical pathways, biological functions, and networks of interacting proteins. Western blotting was used to verify the expression of three selected proteins.

RESULTS

A total of 318 proteins were identified, of which 12 proteins were upregulated in GDM group while 24 downregulated. Lipid metabolism was the top category identified by ingenuity pathway analysis. Three randomly chosen proteins were validated by Western blotting, which were consistent with LC-MS.

CONCLUSION

There are significant differences of protein profile in the umbilical vein blood plasma between normal and GDM patients with obese offspring. The results indicate that a variety of proteins and biological mechanisms may contribute to childhood obesity.

The Rho-guanine nucleotide exchange factor PDZ-RhoGEF governs susceptibility to diet-induced obesity and type 2 diabetes

Adipose tissue is crucial for the maintenance of energy and metabolic homeostasis and its deregulation can lead to obesity and type II diabetes (T2D). Using gene disruption in the mouse, we discovered a function for a RhoA-specific guanine nucleotide exchange factor PDZ-RhoGEF (Arhgef11) in white adipose tissue biology. While PDZ-RhoGEF was dispensable for a number of RhoA signaling-mediated processes in mouse embryonic fibroblasts, including stress fiber formation and cell migration, it's deletion led to a reduction in their proliferative potential. On a whole organism level, PDZ-RhoGEF deletion resulted in an acute increase in energy expenditure, selectively impaired early adipose tissue development and decreased adiposity in adults. PDZ-RhoGEF-deficient mice were protected from diet-induced obesity and T2D. Mechanistically, PDZ-RhoGEF enhanced insulin/IGF-1 signaling in adipose tissue by controlling ROCK-dependent phosphorylation of the insulin receptor substrate-1 (IRS-1). Our results demonstrate that PDZ-RhoGEF acts as a key determinant of mammalian metabolism and obesity-associated pathologies.

DOI:http://dx.doi.org/10.7554/eLife.06011.001

Obesity is a growing public health concern around the world, and can lead to the development of type 2 diabetes, heart disease and cancer. Both genetics and environmental factors such as diet contribute to obesity. Fat cells are essential to good health, but the excess accumulation of fat cells in obese people involves a complex process that is regulated by interactions between numerous genes, cellular messengers and mechanical forces. Learning more about these factors could help prevent or treat obesity.

One mutation in the gene encoding a protein called PDZ-RhoGEF has been linked to both obesity and type 2 diabetes. People with mutations in this gene are not responsive enough to insulin, a hormone important for sugar metabolism. This can interfere with the body’s ability to burn energy in food or lead to a dangerous build up of sugar in the blood as seen in type 2 diabetes. But exactly what PDZ-RhoGEF normally does to prevent this is unclear.

Chang et al. now show that PDZ-RhoGEF controls fat cell production and the body’s ability to release the energy contained in food. First, mice that had been genetically engineered to lack PDZ-RhoGEF were compared to typical mice. The mice without PDZ-RhoGEF had fewer fat cells than the typical mice, and they burned more energy. The mutant mice walked around about as much as the typical mice but they were more likely to have repetitive movements, the mouse equivalent of human nervous ticks.

Insulin normally stimulates the production of fat cells. But the mutant mice were less able to produce fat cells as they developed into adults. When fed a high fat food diet, the normal mice became fatter and insensitive to insulin and developed other health problems linked to excess fat in the body. The mutant mice on the same diet, however, stayed thin and avoided these health issues. The experiments show that PDZ-RhoGEF helps relay insulin’s message within the body, and as such it plays a critical role in regulating metabolism, sugar levels and fat accumulation. Future work should ask how PDZ-RhoGEF affects other complications linked to obesity, and explore the possibility of developing treatments for obesity based on the biology of this molecule.

DOI:http://dx.doi.org/10.7554/eLife.06011.002

Human Rho guanine nucleotide exchange factor 11 gene is associated with schizophrenia in a Japanese population

OBJECTIVE

The human Rho guanine nucleotide exchange factor 11 (ARHGEF11) gene is one of the candidate genes for type 2 diabetes mellitus (T2DM). ARHGEF11 is mapped to chromosome 1q21, which has susceptible risk loci for T2DM and schizophrenia. We hypothesized that ARHGEF11 contributes to the pathogenesis of schizophrenia.

METHOD

We selected eight single nucleotide polymorphisms of ARHGEF11 that had significant associations with T2DM for a case-control association study of 490 patients with schizophrenia and 500 age-matched and sex-matched controls.

RESULTS

We did not find any differences in allelic, genotypic associations, or minor allele frequencies with schizophrenia. Analysis of the rs6427340-rs6427339 haplotype and the rs822585-rs6427340-rs6427339 haplotype combination provided significant evidence of an association with schizophrenia (global permutations p = 0.00047 and 0.0032, respectively). C-C of the rs6427340-rs6427339 haplotype and A-C-C of the rs822585-rs6427340-rs6427339 haplotype carried higher risk factors for schizophrenia (permutation p = 0.0010 and 0.0018, respectively). A-C-T of the rs822585-rs6427340-rs6427339 haplotype had a possible protective effect (permutation p = 0.031).

CONCLUSION

These results provide new evidence that ARHGEF11 may constitute a risk factor for schizophrenia.

Association between the g.14461A>G genetic polymorphism of the TLR4 gene and type 2 diabetes mellitus risk in a Chinese population

OBJECTIVE

Toll-like receptor 4 (TLR4) is an important candidate gene for mediating the susceptibility to type 2 diabetes mellitus (T2DM). The purpose of this study was to investigate the association between the TLR4 gene polymorphisms and T2DM susceptibility.

METHODS

A total of 671 T2DM patients and 677 healthy controls were recruited in this study. The created restriction site-polymerase chain reaction and DNA sequencing methods have been used to analyze the TLR4 gene polymorphisms.

RESULTS

One novel genetic polymorphism (g.14461A>G) was found. Our data indicated that the g.14461A>G genetic polymorphism was significantly associated with the increased susceptibility to T2DM in a homozygote comparison (GG vs. AA: odds ratio [OR]=2.09, 95% confidence interval [CI] 1.44-3.04, p<0.001), dominant model (GG/AG vs. AA: OR=1.27, 95% CI 1.03-1.57, p=0.028), recessive model (GG vs.

AG/AA

OR=1.98, 95% CI 1.39-2.83, p<0.001), and allele contrast (G vs. A: OR=1.33, 95% CI 1.13-1.57, p=0.001). The allele-G might be the risk allele for enhancing the susceptibility to T2DM.

CONCLUSION

These preliminary findings suggest that the g.14461A>G genetic polymorphism of the TLR4 gene is potentially related to the susceptibility to T2DM in the studied population.