β-3 adrenergic receptor gene polymorphisms are associated with gestational diabetes mellitus in a Chinese population

Increasing studies demonstrated that genetic susceptibility attributes to the development of gestational diabetes mellitus (GDM). The polymorphisms of the β-3 adrenergic receptor(β-3AR) gene have been found to be of great importance in bodyweight elevation and dyslipidaemias. We aimed to determine the influence of β-3AR polymorphisms on the GDM risk. Thus, we performed a case-control study including 136 GDM cases and 138 controls to evaluate the relation between the rs201607471 and susceptibility to GDM. Likelihood ratios X analysis showed the distribution of the genotype frequency (rs201607471 in β-3AR gene) was accorded with the Hardy-Weinberg genetic equilibrium. Although no significant association between rs201607471 alleles and GDM susceptibility (Chi-square test, P > .05), we observed that β-3AR gene rs201607471 CT genotype was significantly prevalent in GDM (Chi-square test, P < .05). Moreover, we observed that β-3AR gene rs201607471 C > T was significantly associated with an increased risk of GDM using the recessive model (CC vs CT/TT: P = .026) and the additive model (CC vs CT vs TT: P = .038). These data indicate that β-3AR rs201607471 may be a helpful susceptibility marker for GDM in Chinese pregnant women.

Molecular pathways disrupted by gestational diabetes mellitus

Gestational diabetes mellitus (GDM) imposes serious short- and long-term health problems for mother and baby. An effective therapeutic that can reduce the incidence of GDM and improve long-term maternal and fetal outcomes is a major research priority, crucially important for public health. A lack of knowledge about the underlying pathophysiology of GDM has hampered the development of such therapeutics. What we do know, however, is that maternal insulin resistance, low-grade inflammation and endothelial cell dysfunction are three central features of pregnancies complicated by GDM. Indeed, data generated over the past decade have implicated a number of candidate regulators of insulin resistance, inflammation and endothelial cell dysfunction in placenta, maternal adipose tissue and skeletal muscle. These include nuclear factor-κB (NF-κB), peroxisome proliferator-activated receptors (PPARs), sirtuins (SIRTs), 5' AMP-activated protein kinase (AMPK), glycogen synthase kinase 3 (GSK3), PI3K/mTOR, inflammasome and endoplasmic reticulum (ER) stress. In this review, the identification of these as key modulators of GDM will be discussed. The biochemical pathways involved in the formation of these may represent potential sites for intervention that may translate to therapeutic interventions to prevent the development of GDM.

Common Type 2 Diabetes Genetic Risk Variants Improve the Prediction of Gestational Diabetes

Gestational diabetes mellitus (GDM) is a carbohydrate intolerance that occurs in women during pregnancy. The aims of this study were to develop a model to predict the risk of GDM development using common clinical parameters and selected genetic polymorphisms and to analyse the performance of the model using receiver operator characteristic (ROC) curves. ROC analysis was used to examine whether the evaluation of genetic polymorphisms may enhance the accuracy of GDM prediction in comparison to using common clinical risk factors only. This study included 204 pregnant women with GDM and 207 pregnant women with normal glucose tolerance. The diagnosis of GDM was based on a 75 g oral glucose tolerance test at 24-28 weeks gestation. The difference between the AUC of ROC curves for the model 1 including only age and BMI and the model 2 also including 8 genetic polymorphisms was highly significant (p=0.0001) in favour of model 2 (0.090±0.023). Moreover, the additional use of 8 genetic polymorphisms may increase both the sensitivity and specificity of GDM prediction by 10%. The results of this study indicate that the use of 8 genetic polymorphisms associated with carbohydrate and lipid metabolism and type 2 diabetes [PTGS2 (COX2) rs6681231, FADS1 rs174550, HNF1B rs4430796, ADIPOQ rs266729, IL18 rs187238, CCL2 rs1024611, HHEX rs5015480 and CDKN2A/2B rs10811661] together with clinical risk factors (BMI and age) may significantly improve the prediction of GDM.

Astragaloside IV attenuates gestational diabetes mellitus via targeting NLRP3 inflammasome in genetic mice

BACKGROUND

As the most ordinary metabolic disorder during pregnancy, gestational diabetes mellitus (GDM) has become a severe risk for the health of both pregnant female and fetus. Astragaloside IV (AS-IV) is the dominant active component in Astragalus membranaceus. It has been proved that AS-IV has anti-inflammation and immune-regulation function. We aimed to demonstrate the function of AS-IV in the therapy of GDM and the molecular mechanism in this process.

METHODS

C57BL/KsJ-Lepdb/+ female mice were used as GDM model. The mRNA levels of relative genes in this research were detected by qRT-PCR. The protein levels of relative genes were analyzed by western blot. Serum concentration of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) were analyzed by ELISA.

RESULTS

Glucose and insulin levels in GDM mice model were decreased by AS-IV treatment. AS-IV down-regulated the expression of inflammatory gene IL-6 and TNF-α in GDM mice model. AS-IV treatment inhibited the expression of NLR family pyrin domain containing-3 (NLRP3) inflammasome relative proteins in the pancreas of GDM mice.

CONCLUSION

This study demonstrated that AS-IV treatment has an effective therapeutic function of GDM in mice model through the inhibition of NLRP3 inflammasome in the pancreas.

Genetic susceptibility, lifestyle intervention and glycemic changes among women with prior gestational diabetes

AIMS

Women with prior gestational diabetes mellitus (GDM) or high genetic susceptibility are prone to development of type 2 diabetes. We examined whether a lifestyle intervention modified the genetic effect on changes in glycemic markers among women with prior GDM.

RESEARCH DESIGN AND METHODS

This study included 560 women with prior GDM from a randomized controlled trial, the Tianjin Gestational Diabetes Mellitus Prevention Program, who were assigned into an intervention arm (improved physical activity and healthy dietary intakes) or a control arm. We assessed associations of GDM related genetic variants in/near the CDKAL1 (rs7754840) and MTNR1B (rs10830962) genes with changes in fasting levels of glucose and insulin, β-cell function (HOMA-B) and insulin resistance (HOMA-IR) at 1 year and 2 years after the baseline.

RESULTS

We found significant interactions between CDKAL1 variant rs7754840 and lifestyle intervention on changes in fasting insulin and HOMA-IR at 1 year (P for interactions = 0.008 and 0.006, respectively). The GDM-increasing C allele was associated with a 0.07-unit greater increase in fasting insulin (P = 0.048) and HOMA-IR (P = 0.045) in the control group, while opposite-directional associations were observed in the intervention group; women with the C allele seemed to decrease more in these glycemic markers than the non-C-carriers (both P ≤ 0.06). The interactions between the CDKAL1 genetic variant and lifestyle intervention on changes in fasting insulin (P = 0.035) and HOMA-IR (P = 0.024) remained significant over the 2-year period, even though the effects of lifestyle intervention were attenuated at 2-year. The MTNR1B variant rs10830962 did not show interaction with lifestyle intervention on changes in the glycemic markers.

CONCLUSIONS

Healthy lifestyle intervention may be beneficial for women with the GDM predisposing CDKAL1 genetic variant in improvement of insulin resistance.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT01554358. URL OF REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT01554358.

Lifestyle intervention modifies the effect of the MC4R genotype on changes in insulin resistance among women with prior gestational diabetes: Tianjin Gestational Diabetes Mellitus Prevention Program

BACKGROUND

A history of gestational diabetes mellitus (GDM) has been related to an elevated risk of type 2 diabetes. The melanocortin-4 receptor (MC4R) genotype has been related to glycemic changes in women with prior GDM.

OBJECTIVE

The objective of this study was to analyze whether lifestyle intervention modified the association between the MC4R genotype and changes in insulin sensitivity among women with prior GDM.

METHODS

We genotyped MC4R rs6567160 and measured glucose and insulin in fasting plasma samples at baseline and during the first 2 follow-up visits in 1128 women with prior GDM. They were randomly assigned to either a 4-y lifestyle intervention involving both diet and physical activity or a control group from a randomized clinical trial, the Tianjin Gestational Diabetes Mellitus Prevention Program. We analyzed the interaction between the MC4R genotype and lifestyle intervention on changes in insulin resistance.

RESULTS

From baseline to 1.28 y, the MC4R genotype was related to changes in fasting insulin, HOMA-IR, and homeostasis model assessment of β cell function (HOMA-B) in the intervention group. Each risk allele (C) of rs6567160 was associated with a 0.08-unit greater decrease in log(insulin), log(HOMA-IR), and log(HOMA-B) (P = 0.02, 0.04, and 0.04, respectively), whereas in the control group, each C allele tended to be associated with a greater increase in HOMA-IR (P = 0.09). We found significant interactions between the MC4R genotype and lifestyle intervention on 1.28-y changes in fasting insulin and HOMA-IR (P = 0.006 and 0.008, respectively), and such interaction remained significant when we analyzed the trajectory of changes in insulin and HOMA-IR from baseline to 2.55 y (both P = 0.03).

CONCLUSIONS

The exploratory results from the first 2 follow-up visits indicate that women with prior GDM carrying a diabetes-increasing MC4R genotype (CC or TC) may obtain better improvement than the TT genotype in insulin resistance through lifestyle intervention. This trial was registered at clinicaltrials.gov as NCT01554358.

A spontaneous pregnancy and successful delivery in a Chinese female with Silver-Russell syndrome accompanied by gestational diabetes mellitus

Silver-Russell syndrome (SRS) is a heterogeneous disorder characterized by severe intrauterine and postnatal growth retardation and typical dysmorphic features including body asymmetry, relative macrocephaly, protruding forehead, and feeding difficulties. Previous descriptions of SRS focus on the management of specific issues in children. Herein, we present clinical and metabolic characteristics of an adult woman with SRS accompanied by gestational diabetes mellitus (GDM). Given the rare circumstances presented in our case, the emerging questions concerning the management of metabolic issues and fertility potential in adult SRS patient deserve more attention. Further, long-term follow up is essential to gain future insights into the natural history and optimal management in adulthood.

Molecular Insight into the Interaction between Epigenetics and Leptin in Metabolic Disorders

Nowadays, it is well-known that the deregulation of epigenetic machinery is a common biological event leading to the development and progression of metabolic disorders. Moreover, the expression level and actions of leptin, a vast adipocytokine regulating energy metabolism, appear to be strongly associated with epigenetics. Therefore, the aim of this review was to summarize the current knowledge of the epigenetic regulation of leptin as well as the leptin-induced epigenetic modifications in metabolic disorders and associated phenomena. The collected data indicated that the deregulation of leptin expression and secretion that occurs during the course of metabolic diseases is underlain by a variation in the level of promoter methylation, the occurrence of histone modifications, along with miRNA interference. Furthermore, leptin was proven to epigenetically regulate several miRNAs and affect the activity of the histone deacetylases. These epigenetic modifications were observed in obesity, gestational diabetes, metabolic syndrome and concerned various molecular processes like glucose metabolism, insulin sensitivity, liver fibrosis, obesity-related carcinogenesis, adipogenesis or fetal/early postnatal programming. Moreover, the circulating miRNA profiles were associated with the plasma leptin level in metabolic syndrome, and miRNAs were found to be involved in hypothalamic leptin sensitivity. In summary, the evidence suggests that leptin is both a target and a mediator of epigenetic changes that develop in numerous tissues during metabolic disorders.

N-3 Polyunsaturated Fatty Acids Decrease Long-Term Diabetic Risk of Offspring of Gestational Diabetes Rats by Postponing Shortening of Hepatic Telomeres and Modulating Liver Metabolism

The long-term influence of gestational diabetes mellitus (GDM) on offspring and the effect of omega-3 polyunsaturated fatty acids (n-3 PUFA) on GDM offspring are poorly understood. We studied the long-term diabetic risk in GDM offspring and evaluated the effect of n-3 PUFA intervention. Healthy offspring rats were fed standard diet (soybean oil) after weaning. GDM offspring were divided into three groups: GDM offspring (soybean oil), n-3 PUFA adequate offspring (fish oil), and n-3 PUFA deficient offspring (safflower oil), fed up to 11 months old. The diabetic risk of GDM offspring gradually increased from no change at weaning to obvious impaired glucose and insulin tolerance at 11 months old. n-3 PUFA decreased oxidative stress and inflammation in the liver of older GDM offspring. There was a differential effect of n-3 PUFA and n-6 PUFA on hepatic telomere length in GDM offspring. Non-targeted metabolomics showed that n-3 PUFA played a modulating role in the liver, in which numerous metabolites and metabolic pathways were altered when GDM offspring grew to old age. Many metabolites were related to diabetes risk, such as α-linolenic acid, palmitic acid, ceramide, oxaloacetic acid, tocotrienol, tetrahydro-11-deoxycortisol, andniacinamide. In summary, GDM offspring exhibited obvious diabetes risk at old age, whereas n-3 PUFA decreased this risk.

Unhealthy Levels of Phthalates and Bisphenol A in Mexican Pregnant Women with Gestational Diabetes and Its Association to Altered Expression of miRNAs Involved with Metabolic Disease

Several studies indicate that bisphenol A (BPA) and phthalates may have a role in the development of metabolic diseases using different molecular pathways, including epigenetic regulatory mechanisms. However, it is unclear whether exposure to these chemicals modifies serum levels of miRNAs associated with gestational diabetes mellitus (GDM) risk. In the present study, we evaluated the serum levels of miRNAs associated with GDM (miR-9-5p, miR-16-5p, miR-29a-3p and miR-330-3p) and urinary levels of phthalate metabolites (mono-n-butyl phthalate (MBP), mono-isobutyl phthalate (MiBP), mono-benzyl phthalate (MBzP) and mono(2-ethyl hexyl) phthalate (MEHP)) and bisphenol A in GDM patients and women without GDM during the second trimester of gestation. We observed higher levels of miR-9-5p, miR-29a-3p and miR-330-3p in sera of patients with GDM compared to non-diabetic subjects. Phthalates were detected in 97–100% of urine samples, while BPA only in 40%. Urinary MEHP and BPA concentrations were remarkably higher in both study groups compared to previously reported data. Unadjusted MEHP levels and adjusted BPA levels were higher in non-diabetics than in GDM patients (p = 0.03, p = 0.02). We found positive correlations between adjusted urinary MBzP levels and miR-16-5p expression levels (p < 0.05), adjusted MEHP concentrations and miR-29a-3p expression levels (p < 0.05). We also found negative correlations between unadjusted and adjusted MBP concentrations and miR-29a-3p expression levels (p < 0.0001, p < 0.05), unadjusted MiBP concentrations and miR-29a-3p expression levels (p < 0.01). Urinary MEHP levels reflect a striking exposure to di(2-ethylhexyl) phthalate (DEHP) in pregnant Mexican women. This study highlights the need for a regulatory strategy in the manufacture of several items containing endocrine disruptors in order to avoid involuntary ingestion of these compounds in the Mexican population.

Gestational Diabetes Epigenetically Reprograms the Cart Promoter in Fetal Ovary, Causing Subfertility in Adult Life

Intrauterine exposure to various adverse conditions during fetal development can lead to epigenetic changes in fetal tissues, predisposing those tissues to disease conditions later in life. An example is gestational diabetes (GD), where the offspring has a higher risk of developing obesity, metabolic disorders, or cardiovascular disease in adult life. In this study, using two well-established GD (streptozotocin- and high-fat and high-sugar-induced) mouse models, we report that female offspring from GD dams are predisposed toward fertility problems later in life. This predisposition to fertility problems is due to altered ovarian expression of a peptide called cocaine- and amphetamine-regulated transcript (CART), which is known to negatively affect folliculogenesis and is induced by elevated leptin levels. Results show that the underlying cause of this altered expression is due to fetal epigenetic modifications involving glucose- and insulin-induced miRNA, miR-101, and the phosphatidylinositol 3-kinase/Akt pathway. These signaling events regulate Ezh2, a histone methyltransferase that promotes H3K27me3, a gene-repressive mark, and CBP/p300, a histone acetyltransferase that promotes H3K27ac, a transcription activation mark, in the fetal ovary. Moreover, the CART promoter has depleted 5-methylcytosine (5mC) and enriched 5-hydroxymethylcytosine (5hmC) levels. The depletion of H3K27me3 and 5mC repressive marks and subsequent increase in H3K27ac and 5hmC gene-activating marks convert the Cartpt promoter to a "superpromoter." This makes the Cartpt promoter more sensitive to leptin levels that predispose the GD offspring to fertility problems. Therefore, this study provides a mechanistic insight about fetal epigenome reprogramming that manifests to ovarian dysfunction and subfertility later in adult life.

Impact of GPR1 signaling on maternal high-fat feeding and placenta metabolism in mice

Chemerin and G protein-coupled receptor 1 (GPR1) are increased in serum and placenta in mice during pregnancy. Interestingly, we observed increased serum chemerin levels and decreased GPR1 expression in placenta of high-fat-diet-fed mice compared with chow-fed mice at gestational day 18. GPR1 protein and gene levels were significantly decreased in gestational diabetes mellitus (GDM) patient placentas. Therefore, we hypothesized that chemerin/GPR1 signaling might participate in the pathogenic mechanism of GDM. We investigated the role of GPR1 in carbohydrate homeostasis during pregnancy using pregnant mice transfected with small interfering RNA for GPR1 or a negative control. GPR1 knockdown exacerbated glucose intolerance, disrupted lipid metabolism, and decreased β-cell proliferation and insulin levels. Glucose transport protein-3 and fatty acid binding protein-4 were downregulated with reducing GPR1 in vivo and in vitro via phosphorylated AKT pathway. Taken together, our findings first demonstrate the expression of GPR1, the characterization of its direct biological effects in humans and mice, as well as the molecular mechanism that indicates the role of GPR1 signaling in maternal metabolism during pregnancy, suggesting a novel feedback mechanism to regulate glucose balance during pregnancy, and GPR1 could be a potential target for the detection and therapy of GDM.

Methylation profile of genes involved in inflammation, in the blood from pregnancies with maternal preeclampsia due to untreated gestational diabetes mellitus

PURPOSE

To investigate DNA methylation changes in peripheral blood from patients with gestational diabetes mellitus (GDM) and preeclampsia (PE) due to poorly treated GDM.

METHODS

Eighteen pregnant women participated in the study: 6 with GDM, 6 with PE, and 6 healthy controls. The promoter methylation status of genes was profiled using the Human Inflammatory Response and Autoimmunity EpiTect Methyl II Signature PCR Array profiles. The results were validated with quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

Fewer inflammation-related genes were significantly hypomethylated in PE cases compared to healthy subjects than in GDM cases. Some of the examined genes show different methylation patterns between GDM and PE.

CONCLUSIONS

The epigenetic changes observed in this study indicate that GDM and PE exhibit specific DNA methylation profiles, with possible clinical applications.

Expression profile of circular RNAs in placentas of women with gestational diabetes mellitus

Forty-five pregnant women who underwent cesarean section, including 30 cases of gestational diabetes mellitus (GDM) and 15 normal pregnant women, were enrolled in this study to examine the differential expression of circular RNAs (circRNAs) in the placentas of women with GDM by RNA sequencing (RNA-seq) analysis. The differentially expressed circRNAs were analyzed bioinformatically using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and circRNA-microRNA (miRNA) interaction prediction. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to verify the results. A total of 8,321 circRNAs were identified in the human placenta, among which 46 were differentially expressed (fold change ≥2 and p < 0.05), including three that were upregulated and 43 that were downregulated. According to the GO and KEGG enrichment results, these circRNAs may be associated with vital biological processes, cellular components, molecular functions, and signaling pathways. In particular, KEGG analysis shown they may be involved in advanced glycation end products-receptor for advanced glycation end products (AGE-RAGE) signaling pathway in diabetic complications, indicating that these circRNAs might participate in the occurrence and pathogenesis of GDM. qRT-PCR verified that the expression of circ_5824, circ_3636, and circ_0395 was consistent with RNA-seq analysis; their expression levels were significantly lower in the GDM group than in the control group. The circRNA-miRNA interaction was analyzed according to the molecular sponge mechanism, and its potential function is discussed. These results shed light on future functional studies of circRNAs related to GDM.

Paraoxonase 1 (PON1) Q192R and L55M polymorphisms, lipid profile, lipid peroxidation and lipoprotein-a levels in Turkish patients with pregnancy-related disorders

The aim of this study was to investigate the role of PON1Q192R and L55M single nucleotide polymorphisms(SNPs) and its association with the maternal levels of lipid parameters in gestational diabetes mellitus(GDM) and preeclampsia(PE). Ninety-nine pregnant with GDM, 97 pregnant with PE and 98 healthy pregnant were included in the study. No statistically significant difference was observed in the alleles or in the genotypes frequencies of SNPs between groups. In GDM patients, total cholesterol was higher in MM genotype of L55M gene (p < .05); Lp(a) were lower in LM genotype of the gene compared to their respective control (p < .05). In PE, HDL-C levels were higher in LM genotype (p < .05); LDL-C levels were lower in MM genotype of the gene compared to their respective control (p < .05). In PE patients, malondialdehyde(MDA) were higher in QQ genotype compared to their respective control (p < .05). Triglyceride levels were higher in PE patients with QR genotype compared with GDM patients with QR genotype (p < .05). Our results indicated that lipid profiles, Lp(a) and MDA levels showed significant differences in GDM and PE pregnants. These findings support the importance of the lipid profile, oxidized lipid and Lp(a) in different genotypes of L55M and Q192R in Turkish pregnant women with PE/GDM suggesting their roles in etiopathogenesis in these pregnancy-related disorders.

Prolactin Receptor Signaling Regulates a Pregnancy-Specific Transcriptional Program in Mouse Islets

Pancreatic β-cells undergo profound hyperplasia during pregnancy to maintain maternal euglycemia. Failure to reprogram β-cells into a more replicative state has been found to underlie susceptibility to gestational diabetes mellitus (GDM). We recently identified a requirement for prolactin receptor (PRLR) signaling in the metabolic adaptations to pregnancy, where β-cell-specific PRLR knockout (βPRLRKO) mice exhibit a metabolic phenotype consistent with GDM. However, the underlying transcriptional program that is responsible for the PRLR-dependent metabolic adaptations during gestation remains incompletely understood. To identify PRLR signaling gene regulatory networks and target genes within β-cells during pregnancy, we performed a transcriptomic analysis of pancreatic islets isolated from either βPRLRKO mice or littermate controls in late gestation. Gene set enrichment analysis identified forkhead box protein M1 and polycomb repressor complex 2 subunits, Suz12 and enhancer of zeste homolog 2 (Ezh2), as novel candidate regulators of PRLR-dependent β-cell adaptation. Gene ontology term pathway enrichment revealed both established and novel PRLR signaling target genes that together promote a state of increased cellular metabolism and/or proliferation. In contrast to the requirement for β-cell PRLR signaling in maintaining euglycemia during pregnancy, PRLR target genes were not induced following high-fat diet feeding. Collectively, the current study expands our understanding of which transcriptional regulators and networks mediate gene expression required for islet adaptation during pregnancy. The current work also supports the presence of pregnancy-specific adaptive mechanisms distinct from those activated by nutritional stress.

Relationship of lactation, BMI, and rs12255372 TCF7L2 polymorphism on the conversion to type 2 diabetes mellitus in women with previous gestational diabetes

Women with previous gestational diabetes mellitus (pGDM) have a high risk of developing postpartum type 2 diabetes mellitus (T2DM). This study aimed to analyze the relationship between lactation, BMI, and TCF7L2 polymorphisms in the conversion to T2DM in women with pGDM. One hundred and fifty-three women con pGDM were recruited from public hospitals of León Guanajuato México. Three groups: normal glucose tolerance (NGT), impaired glucose intolerance (IGT), and T2DM after the oral glucose tolerance test were formed. Metabolic and hormone variables were measured, and genotyping was made by PCR-RFLP. The questionnaire included data on lactation (yes/no), duration of lactation, and full lactation. After 35 (21-49) months from the last partum, 54% of women had an NGT, 30.7% IGT, and 15% T2DM. BMI and rs12255372 are associated with the risk of conversion to IGT and T2DM [OR = 1.07 (95% IC 1.0-1.14, p = .041; OR =2.14, 95% IC 1.01-4.55, p = .04 respectively), while the lactation shows a strong protective effects OR = 0.15 (95% IC 0.062-0.39, p = .00007), and an apparent interaction with rs12255372T decreasing the risk in carriers (OR =2.15; 95% IC 0.97-4.7, p = .05). BMI is an independent risk factor of IGT/T2DM development. The lactation shows a strong protective effect and a possible interaction with rs12255372 polymorphism.

High frequency of pathogenic and rare sequence variants in diabetes-related genes among Russian patients with diabetes in pregnancy

AIMS

Diabetes in pregnancy may be associated with monogenic defects of beta-cell function, frequency of which depends on ethnicity, clinical criteria for selection of patients as well as methods used for genetic analysis. The aim was to evaluate the contribution and molecular spectrum of mutations among genes associated with monogenic diabetes in non-obese Russian patients with diabetes in pregnancy using the next-generation sequencing (NGS).

METHODS

188 non-obese pregnant women with diabetes during pregnancy were included in the study; among them 57 subjects (30.3%) met the American Diabetes Association (ADA) criteria of preexisting pregestational diabetes (pre-GDM), whereas 131 women (69.7%) fulfilled criteria of gestational diabetes mellitus (GDM). A custom NGS panel targeting 28 diabetes causative genes was used for sequencing. The sequence variants were rated according to the American College of Medical Genetics and Genomics (ACMG) guidelines.

RESULTS

In total, 23 pathogenic, 18 likely pathogenic and 16 variants of uncertain significance were identified in 59/188 patients (31.4%). The majority of variants (38/59) were found in GCK gene. No significant differences in the number of variants among the two study groups (pre-GDM and GDM) were observed.

CONCLUSIONS

The study suggests that frequency of monogenic variants of diabetes might be underestimated, which warrants a broader use of genetic testing, especially in pregnancy.

Sex modifies placental gene expression in response to metabolic and inflammatory stress

INTRODUCTION

Metabolic stress (e.g., gestational diabetes mellitus (GDM) and obesity) and infections are common during pregnancy, impacting fetal development and the health of offspring. Such antenatal stresses can differentially impact male and female offspring. We sought to determine how metabolic stress and maternal immune activation (MIA), either alone or in combination, alters inflammatory gene expression within the placenta and whether the effects exhibited sexual dimorphism.

METHODS

Female C57BL/6 J mice were fed a normal diet or a high fat diet for 6 weeks prior to mating, with the latter diet inducing a GDM phenotype during pregnancy. Dams within each diet group at gestational day (GD) 12.5 received either an intraperitoneal injection of the viral mimic, polyinosinic:polycytidylic acid (poly(I:C)) or saline. Three hours post injection; placentae were collected and analyzed for changes in the expression of 248 unique immune genes.

RESULTS

Placental immune gene expression was significantly altered by GDM, MIA and the combination of the two (GDM+MIA). mRNA expression was generally lower in placentae of mice exposed to GDM alone compared with the other experimental groups, while mice exposed to MIA exhibited the highest transcript levels. Notably, fetal/placental sex influenced the responses of many immune genes to both metabolic and inflammatory stress.

DISCUSSION

GDM and MIA provoke inflammatory responses within the placenta and such effects exhibit sexual dimorphism. The combination of these stressors impacts the placenta differently than either condition alone. These findings may help explain sexual dimorphism observed in adverse pregnancy outcomes in human offspring exposed to similar stressors.

Association of polymorphisms in STRA6 gene with gestational diabetes mellitus in a Chinese Han population

Cell and animal experiments have found that in addition to being a retinol transporter, Stimulated by Retinoic Acid 6 (STRA6) also functions as a surface signaling receptor by which retinol regulates insulin responses. Several studies revealed that the STRA6 gene may contribute to the pathogenesis of type 2 diabetes mellitus (T2DM). Gestational diabetes mellitus (GDM) and T2DM have some risk factors in common. The present study was directed to investigate whether the 3 single nucleotide polymorphism (SNPs) (rs11633768, rs351219, and rs736118) of STRA6 correlate with the development of GDM in Chinese pregnant women. We also aimed to estimate the relationship between SNPs with fasting blood glucose level, 1-hour and 2-hour blood glucose levels after 75 g oral glucose intake, fasting insulin and insulin resistance levels to better study the relationship between STRA6 and glucose metabolism.Case-control studies were conducted to compare the GDM and control groups. A total of 334 cases and 367 controls were recruited. Three tagSNPs of STRA6, rs11633768, rs351219, and rs736118, were selected. A chi-square test, logistic regression, and linear regression were used to estimate the relationship between SNPs with GDM risk and oral glucose tolerance test (OGTT), fasting insulin and homeostasis model assessment of insulin resistance (HOMA-IR) levels. Regression analyses were all adjusted by maternal age, pre-pregnancy BMI, and weekly BMI growth. The Bonferroni correction was applied for multiple comparisons.After adjusting the maternal age, pre-pregnancy BMI and weekly BMI growth, STRA6 rs736118 was associated with fasting insulin level (Beta = -1.468, P = .036), and the association between rs736118 and HOMA-IR was of borderline significance (Beta = -0.290, P = .093) under the dominance model.This study found that there is a significant association between STRA6 polymorphism and GDM.

High glucose alters fetal rat islet transcriptome and induces progeny islet dysfunction

Offspring of diabetic mothers are susceptible to developing type 2 diabetes due to pancreatic islet dysfunction. However, the initiating molecular pathways leading to offspring pancreatic islet dysfunction are unknown. We hypothesized that maternal hyperglycemia alters offspring pancreatic islet transcriptome and negatively impacts offspring islet function. We employed an infusion model capable of inducing localized hyperglycemia in fetal rats residing in the left uterine horn, thus avoiding other factors involved in programming offspring pancreatic islet health. While maintaining euglycemia in maternal dams and right uterine horn control fetuses, hyperglycemic fetuses in the left uterine horn had higher serum insulin and pancreatic beta cell area. Upon completing infusion from GD20 to 22, RNA sequencing was performed on GD22 islets to identify the hyperglycemia-induced altered gene expression. Ingenuity pathway analysis of the altered transcriptome found that diabetes mellitus and inflammation/cell death pathways were enriched. Interestingly, the downregulated genes modulate more diverse biological processes, which includes responses to stimuli and developmental processes. Next, we performed ex and in vivo studies to evaluate islet cell viability and insulin secretory function in weanling and adult offspring. Pancreatic islets of weanlings exposed to late gestation hyperglycemia had decreased cell viability in basal state and glucose-induced insulin secretion. Lastly, adult offspring exposed to in utero hyperglycemia also exhibited glucose intolerance and insulin secretory dysfunction. Together, our results demonstrate that late gestational hyperglycemia alters the fetal pancreatic islet transcriptome and increases offspring susceptibility to developing pancreatic islet dysfunction.

Single Nucleotide Polymorphisms in CDKAL1 Gene Are Associated with Risk of Gestational Diabetes Mellitus in Chinese Population

Gestational diabetes mellitus (GDM) is a growing public health concern for many reasons, and its etiology remains unclear. Due to the similarity of its pathophysiology with type 2 diabetes (T2DM), we evaluated the relationship between published T2DM susceptibility genes and the risk of GDM. A total of 303 SNPs from genes including IRS1, IGF2BP2, CDKAL1, GCK, TCF7L2, KCNQ1, and KCNJ11 and the risk of GDM were examined in a nested case-control study with 321 GDM cases and 316 controls. The odds ratios (ORs) and their 95% confidence interval (95% CI) were estimated by unconditional logistical regression as a measure of the associations between genotypes and GDM in additive, recessive, dominant, and codominant models adjusting for maternal age, maternal BMI, parity, and family history of diabetes. At the gene level, CDKAL1 was associated with GDM risk. SNPs in the CDKAL1 gene including rs4712527, rs7748720, rs9350276, and rs6938256 were associated with reduced GDM risk. However, SNPs including rs9295478, rs6935599, and rs7747752 were associated with elevated GDM risk. After adjusting for multiple comparisons, rs9295478 and rs6935599 were still significant across the additive, recessive, and codominant models; rs7748720 and rs6938256 were significant in dominant and codominant models; and rs4712527 was only significant in the codominant model. Our study provides evidence for an association between the CDKAL1 gene and risk of GDM. However, its role in the GDM pathogenesis still needs to be verified by further studies.

Expression of Dual-Specificity Phosphatase 9 in Placenta and Its Relationship with Gestational Diabetes Mellitus

INTRODUCTION

The aim of the present study was to examine placental levels of DUSP9 mRNA and protein and to investigate the potential role of DUSP9 in the development of gestational diabetes mellitus (GDM).

METHODS

Placental tissues from pregnant women with GDM (n = 17) and normal healthy pregnant women (n = 16) were collected at delivery. The expression of DUSP9 mRNA in placental tissue was analyzed by real-time PCR, while the expression of DUPS9 protein was evaluated by immunohistochemistry and western blot. Differences in the expression levels of DUSP9 mRNA and protein between the two groups were assessed, as well as potential correlations between DUSP9 mRNA expression levels and relevant clinical indicators.

RESULTS

Blood glucose levels were significantly higher in the GDM group than in the control group, based on an oral glucose tolerance test. DUSP9 protein was expressed in the placental cytotrophoblasts in both groups, and placental levels of DUSP9 protein and mRNA were significantly higher in women with GDM. Placental DUSP9 mRNA levels in all 33 women correlated moderately with delivery gestational week (R = 0.465, P = 0.006), fasting plasma glucose (R = 0.350, P = 0.046), 1-hour postload plasma glucose (R = 0.363, P = 0.038), and 2-hour postload plasma glucose (R = 0.366, P = 0.036), but not with maternal age, preconception body mass index, prenatal body mass index, or neonatal birth weight. Multiple linear regression analysis indicated that delivery gestational week was an influence factor of DUSP9 mRNA levels (β ₁ = 0.026, P < 0.05).

CONCLUSIONS

DUSP9 upregulation in the placenta of GDM pregnant women may promote insulin resistance, which may correlate with the occurrence of GDM. But there is still possibility that DUSP9 upregulation was the results of insulin resistance and/or hyperglycemia. Further research is needed to explore the role of DUSP9 in GDM.

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.

Transient PAX8 Expression in Islets During Pregnancy Correlates With β-Cell Survival, Revealing a Novel Candidate Gene in Gestational Diabetes Mellitus

Transient Pax8 expression was reported in mouse islets during gestation, whereas a genome-wide linkage and admixture mapping study highlighted PAX8 as a candidate gene for diabetes mellitus (DM). We sought the significance of PAX8 expression in mouse and human islet biology. PAX8 was induced in gestating mouse islets and in human islets treated with recombinant prolactin. Global gene expression profiling of human and mouse islets overexpressing the corresponding species-specific PAX8 revealed the modulation of distinct genetic pathways that converge on cell survival. Accordingly, apoptosis was reduced in PAX8-overexpressing islets. These findings support that PAX8 could be a candidate gene for the study of gestational DM (GDM). PAX8 was genotyped in patients with GDM and gestational thyroid dysfunction (GTD), a pathology commonly found in patients with mutations on PAX8 A novel missense PAX8 mutation (p.T356M, c.1067C>T) was identified in a female diagnosed with GDM and GTD as well as in her father with type 2 DM but was absent in control patients. The p.T356M variant did not alter protein stability or cellular localization, whereas its transactivation activity was hindered. In parallel, a retrospective clinical analysis uncovered that a pregnant female harboring a second PAX8 mutation (p.P25R, c.74C>G) previously reported to cause congenital hypothyroidism also developed GDM. These data indicate that increased expression of PAX8 affects islet viability and that PAX8 could be considered as a candidate gene for the study of GDM.