Association of the estrogen receptor-alpha gene with the metabolic syndrome and its component traits in African-American families: the Insulin Resistance Atherosclerosis Family Study

Effect of ovariectomy and high-fat diet on the expression of estrogen receptors and adipose tissue metabolism in wistar rats

This study addresses the increasing prevalence of obesity, especially among postmenopausal. Estrogen plays a crucial role in regulating adipose tissue in women, with its absence after menopause associated with metabolic complications. The study aimed to determine the lipolytic activity in different adipose tissue depots of ovariectomized rats submitted to a high-fat diet. Also, to analyze the expression of estrogen receptors in adipose tissues and perform histological and morphometric analyzes of these deposits. Female rats were ovariectomized (O) or sham operated (S). The animals were divided into groups: ovariectomized with high-fat diet (OF), sham-operated with high-fat diet (SF), ovariectomized with control diet (OC) or sham-operated with control diet as the control group (SC). After 24 weeks of consuming the diets, rats were killed and adipose tissue deposits were removed. Polymerase chain reaction was performed to analyze the expression of estrogen receptors in adipose tissues, lipolysis assay and histological analysis. Both the high-fat diet and ovariectomy increased body weight and adiposity. There was hypertrophy of adipocytes. Estrogen replacement therapy modulate lipolytic activity in different adipose depots, with different responses in relation to estrogen receptors. Estrogen receptor expression varied between fat depots. Mesenteric adipose tissue showed greater sensitivity to estrogen compared with others. Estrogen increased lipolytic activity in some fat depots, reducing in others. Expression of ERs depends of hormonal status and adipose tissue location, which may explain distinct actions of estrogen on the metabolism of adipose tissue and on the production of adipokines by them.

Metformin Prevents Tumor Cell Growth and Invasion of Human Hormone Receptor-Positive Breast Cancer (HR+ BC) Cells via FOXA1 Inhibition

Women with type 2 diabetes (T2D) have a higher risk of being diagnosed with breast cancer and have worse survival than non-diabetic women if they do develop breast cancer. However, more research is needed to elucidate the biological underpinnings of these relationships. Here, we found that forkhead box A1 (FOXA1), a forkhead family transcription factor, and metformin (1,1-dimethylbiguanide hydrochloride), a medication used to treat T2D, may impact hormone-receptor-positive (HR+) breast cancer (BC) tumor cell growth and metastasis. Indeed, fourteen diabetes-associated genes are highly expressed in only three HR+ breast cancer cell lines but not the other subtypes utilizing a 53,805 gene database obtained from NCBI GEO. Among the diabetes-related genes, FOXA1, MTA3, PAK4, FGFR3, and KIF22 were highly expressed in HR+ breast cancer from 4032 breast cancer patient tissue samples using the Breast Cancer Gene Expression Omnibus. Notably, elevated FOXA1 expression correlated with poorer overall survival in patients with estrogen-receptor-positive/progesterone-receptor-positive (ER+/PR+) breast cancer. Furthermore, experiments demonstrated that loss of the FOXA1 gene inhibited tumor proliferation and invasion in vitro using MCF-7 and T47D HR+ breast cancer cell lines. Metformin, an anti-diabetic medication, significantly suppressed tumor cell growth in MCF-7 cells. Additionally, either metformin treatment or FOXA1 gene deletion enhanced tamoxifen-induced tumor growth inhibition in HR+ breast cancer cell lines within an ex vivo three-dimensional (3D) organoid model. Therefore, the diabetes-related medicine metformin and FOXA1 gene inhibition might be a new treatment for patients with HR+ breast cancer when combined with tamoxifen, an endocrine therapy.

The Relationship between Time, Race, and Estrogen Receptor Alpha in Estradiol-Induced Dermal Fibrosis

In the skin, estradiol (E2) promotes profibrotic and proinflammatory cytokines, contributing to extracellular matrix (ECM) deposition. However, the magnitude of the response differs. Using the human skin organ culture model, we evaluated donor characteristics and correlations that contribute to E2-induced interleukin-6 (IL-6), transforming growth factor beta 1 and 2 (TGFB1 and TGFB2), collagen IA2 (Col IA2), collagen IIIA1 (Col IIIA1), and fibronectin (FN) expressions. In vehicle- and E2-treated dermal skin tissue transcripts, we confirm differences in the magnitude; however, there were positive correlations between profibrotic mediators and ECM components 48 h after E2 treatment. Also, positive correlations exist between baseline and E2-induced TGFB1, IL-6, Col IIIA1, and FN transcripts. Since estrogen receptor alpha (ERA) can propagate E2's signal, we measured and detected differences in its baseline and fold change transcript levels, with a significant decline in baseline levels 48 h after incubation and an increase 48 h after E2 treatment. There was a trend to higher transcript levels in African American donors 24 h earlier. Finally, E2-induced ERA transcript levels negatively correlated with its own baseline levels and positively correlated with FN, TGFB1, and Col IA2 transcript levels. Therefore, our data suggest ERA, E2 exposure time, and race/ethnicity contribute to E2-induced dermal fibrosis.

Potential Mechanisms of Biejiajian Pill in the Treatment of Diabetic Atherosclerosis Based on Network Pharmacology, Molecular Docking, and Molecular Dynamics Simulation

Background

Biejiajian pill (BJJP), a classical traditional Chinese formula, has been reported that it has an effective treatment for diabetic atherosclerosis in recent years, but its underlying mechanisms remain elusive. The study aimed to explore the potential mechanisms of BJJP on diabetic atherosclerosis by integrating network pharmacology, molecular docking, and molecular dynamics simulation.

Methods

The active components of BJJP were collected by TCMSP and TCMID, and then the potential targets were obtained from the SwissTargetPrediction database. The targets related to diabetic atherosclerosis were identified from the GeneCards and OMIM databases. The intersection of the potential targets regulated by active components of BJJP and the targets of diabetic atherosclerosis were common targets, which were visualized by the Venn diagram. The common targets were imported into the STRING database to construct a protein-protein interaction (PPI) network. The network of “Medicine-Compound-Target” was constructed with Cytoscape 3.7.1 software. GO functional enrichment analysis and KEGG pathway enrichment analysis were performed using the DAVID database and visualized through bioinformatics. The intersecting targets were input into Cytoscape 3.7.1 software, and the Network Analyzer tool was employed to screen out the key targets. Then molecular docking was used to verify the binding affinity between the active compounds and the key targets, and molecular dynamics simulation was used to investigate the stability of the binding models.

Results

A total of 81 active components, 186 targets of BJJP, and 4041 targets of diabetic atherosclerosis were obtained. Furthermore, 121 overlapping targets were identified. GO functional enrichment analysis revealed that these targets were correlated with the oxidation-reduction process, negative regulation of apoptotic process, inflammatory response, and other biological processes. The results of the KEGG pathway enrichment analysis showed that the common targets mainly participated in proteoglycans in cancer, PPAR signaling pathway, adherens junction, insulin resistance, HIF-1 signaling pathway, PI3K-Akt signaling pathway, etc. The results of molecular docking confirmed that the core active components in BJJP could bind well to the key targets. Results from molecular dynamics simulation showed that the binding energies of AKT1-Luteolin, MMP9-quercetin, and MMP9-luteolin complexes were −28.93 kJ·mol⁻¹, −37.12 kJ·mol⁻¹, and −62.91 kJ·mol⁻¹, respectively.

Conclusion

The study revealed that BJJP is characterized as multicomponent, multitarget, and multipathway to treat diabetic atherosclerosis, which is helpful to provide ideas and a basis for pharmacological research and clinical application in the future.

Metabolic Syndrome, BMI, and Polymorphism of Estrogen Receptor-α in Peri- and Post-Menopausal Polish Women

The study aimed to investigate the association between the estrogen receptor alpha (ERα) polymorphism and the prevalence of metabolic syndrome (MetS) and obesity, as well as the coexistence of MetS and obesity, in peri- and post-menopausal Polish women. The study group consisted of 202 peri-menopausal and 202 post-menopausal women. ERα polymorphism: Xba I and Pvu II, MetS, BMI, and serum estrogen concentration were analyzed. MetS was found in 29% of the peri-menopausal women and in 21% of the post-menopausal women. BMI did not significantly differ between the peri- and post-menopausal women (≈42% were normal weight, ≈40% were overweight, and ≈18% were obese), (p = 0.82). Serum estrogen concentration in the peri-menopausal women was 91 ± 75 pg/mL, while that in the post-menopausal women was 17 ± 9. pg/mL, on average. Peri-menopausal women with AA and TT genotypes of the ERα polymorphism have a lower risk of obesity and MetS and the co-existence of obesity and MetS, whereas those women with the G or C allele have a higher risk of those health problems.

Association of Serum Galectin-3-Binding Protein and Metabolic Syndrome in a Chinese Adult Population

BACKGROUND

Galectin-3-binding protein (GAL-3BP) is a ubiquitous and multifunctional secreted glycoprotein, which functions in innate immunity and has been highlighted as a potential mediator of adipose inflammation in obesity. In this study, we aimed to identify whether GAL-3BP is a novel biological marker for metabolic syndrome (MetS).

METHODS

The biochemical and anthropometric variables of the 570 participants in this study were evaluated using standard procedures. Their serum GAL-3BP levels were measured using enzyme-linked immunosorbent assay (ELISA), while the association between the glycoprotein and MetS was analyzed using multiple logistic regression analyses. Moreover, an experimental MetS model was established. The expression of GAL-3BP in serum and adipose tissue was measured using ELISA and western blotting. Lipid accumulation was determined with the use of immunohistochemistry and immunofluorescent staining.

RESULTS

The serum GAL-3BP level was found to be positively associated with MetS. The logistic regression analyses demonstrated that participants expressing the upper levels of GAL-3BP were more likely to develop MetS than those expressing less of the glycoprotein (OR = 2.39, 95%CI: 1.49, 3.83). The association between the serum GAL-3BP level and MetS was found preferentially in postmenopausal women (OR = 2.30, 95%CI: 1.31, 4.05). In addition, GAL-3BP was increased in the serum and visceral adipose tissue (VAT) of high fat diet (HFD) mice. Moreover, GAL-3BP was highly expressed in VAT macrophages.

CONCLUSIONS

This study confirmed serum GAL-3BP to be positively associated with MetS, highlighting it as a useful biological marker of MetS in Chinese participants.

The rs2175898 Polymorphism in the ESR1 Gene has a Significant Sex-Specific Effect on Obesity

Polymorphisms in the ESR1 gene have been associated with obesity and lipid metabolism. There are also important sex-related differences in the prevalence of obesity and related phenotypes. Therefore, we aimed to interrogate the association of the ESR1 rs2175898 gene polymorphism with obesity, obesity-related variables, and lipid levels in men and women as separate groups. Two thousand twenty-two randomly selected middle-aged and elderly Turks were genotyped for ESR1 rs2175898 polymorphism using real-time polymerase chain reaction with hybridization probes. We found sex-related differences of the ESR1 rs2175898 polymorphism in obesity. Logistic regression analysis after adjustment for age, smoking status, physical activity, diabetes mellitus, and the presence of menopause status in women demonstrated significantly decreased risk for obesity in female AG genotype carriers (OR 0.69; 95% CI 0.52-0.91; p = 0.010), and in male GG genotype carriers (OR 0.49; 95% CI 0.25-0.96; p = 0.039), Furthermore, carriers of the rs2175898 G allele exhibited a lower body mass index in both sexes and decreased waist circumference in women but not in men. Our findings also showed significantly higher serum total-C levels (p = 0.007) in the carriers of the AG+GG/AG genotype compared with the AA genotype in men. The AG genotype of the ESR1 rs2175898 polymorphism in women and GG genotype in men were found to have a decreased likelihood for obesity compared with the other rs2175898 genotypes.

Disruption of ESR1 alters the expression of genes regulating hepatic lipid and carbohydrate metabolism in male rats

The liver helps maintain energy homeostasis by synthesizing and storing glucose and lipids. Gonadal steroids, particularly estrogens, play an important role in regulating metabolism. As estrogens are considered female hormones, metabolic disorders related to the disruption of estrogen signaling have mostly been studied in females. Estrogen receptor alpha (ESR1) is the predominant receptor in both the male and female liver, and it mediates the hepatic response to estrogens. Loss of ESR1 increases weight gain and obesity in female rats, while reducing the normal growth in males. Although Esr1-/- male rats have a reduced body weight, they exhibit increased adipose deposition and impaired glucose tolerance. We further investigated whether these metabolic disorders in Esr1-/- male rats were linked with the loss of transcriptional regulation by ESR1 in the liver. To identify the ESR-regulated genes, RNA-sequencing was performed on liver mRNAs from wildtype and Esr1-/- male rats. Based on an absolute fold change of ≥2 with a p-value ≤ 0.05, a total of 706 differentially expressed genes were identified in the Esr1-/- male liver: 478 downregulated, and 228 upregulated. Pathway analyses demonstrate that the differentially expressed genes include transcriptional regulators (Cry1, Nr1d1, Nr0b2), transporters (Slc1a2), and regulators of biosynthesis (Cyp7b1, Cyp8b1), and hormone metabolism (Hsd17b2, Sult1e1). Many of these genes are also integral parts of the lipid and carbohydrate metabolism pathways in the liver. Interestingly, certain critical regulators of the metabolic pathways displayed a sexual dimorphism in expression, which may explain the divergent weight gain in Esr1-/- male and female rats despite common metabolic dysfunctions.

Interplays of estrogen receptor alpha gene rs2234693 with post-traumatic stress disorder influence serum glucose and lipids profiles in Chinese adolescents

Both post-traumatic stress disorder (PTSD) and estrogen receptor alpha (ESR1) gene rs2234693 were reported to influence serum glucose and lipids profiles. However, their interactions on serum glucose and lipids profiles have not been reported. A total of 708 Chinese Han high school students were recruited at 6th months after the 2008 Wenchuan Earthquake. Serum concentrations of fasting blood glucose (FBG), fasting blood insulin (FBI), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) were detected. Body mass index (BMI) and homeostatic model assessment of insulin resistance (HOMA-IR) were calculated. PTSD was assessed by the PTSD Checklist Civilian Version (PCL-C). Variants of ESR1 rs2234693 was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses and verified by DNA sequencing. The male subjects with PTSD had a trend of higher FBG (p = 0.077) and significantly higher FBI and HOMA-IR than male controls. The PTSD subjects had significantly higher levels of FBG, FBI, HOMA-IR and HDL-C than the controls only in the male C allele carriers irrespective of adjustment for age and BMI. In the male controls group, the C allele carriers had significantly lower HDL-C than the TT homozygotes regardless of adjustment for age and BMI. In female PTSD group, the C allele carriers had significantly higher TC/HDL-C and LDL-C/HDL-C than the TT homozygotes after adjustment for age and BMI. These results suggest the interplays of ESR1 rs2234693 with PTSD influence serum glucose and lipids profiles with a gender dependent manner.

Estrogen receptor 1 gene polymorphisms are associated with metabolic syndrome in postmenopausal women in China

BACKGROUND

Metabolic syndrome (MetS) includes obesity, diabetes, dyslipidemia and hypertension. Its incidence is rapidly increasing worldwide, particularly in postmenopausal women. Estrogens regulate glucose homeostasis and lipid metabolism via estrogen receptors 1 (ESR1) and 2 (ESR2). The current study aimed to elucidate associations of MetS with ESR1 and ESR2 gene polymorphisms in postmenopausal Chinese women.

METHODS

This case-control study included 304 postmenopausal women (154 and 150 control and MetS patients, respectively). Clinical indicators related to MetS were assessed. Two ESR1 (PvuII and XbaI) and two ESR2 (RsaI and AluI) polymorphisms were evaluated by polymerase chain reaction (PCR)-restriction fragment length polymorphism analysis.

RESULTS

ESR1 polymorphisms were significantly different between MetS patients and healthy controls. G allele frequency for the XbaI polymorphism was significantly higher in patients than in control patients (p = 0.004, OR = 1.610, 95%CI 1.169-2.18). The haplotypes A-T (p = 0.015) and G-C (p = 0.024) showed significant differences. The minor alleles of the XbaI and PvuII gene polymorphisms in both homozygous and heterozygous forms showed associations with elevated waist circumference, fasting serum insulin and HOMA-IR. The minor G allele in homozygous and heterozygous forms of the RsaI and AluI gene polymorphisms showed associations with elevated total cholesterol and LDL-C.

CONCLUSIONS

In postmenopausal Chinese women, ESR1 polymorphism and the haplotypes A-T and G-C of XbaI-PvuII are associated with MetS, unlike ESR2 polymorphisms. Patients harboring the G allele of XbaI have elevated BMI, waist circumference, systolic and diastolic BP, FBG, HOMA-IR, total cholesterol, TG, LDL-C and NAFLD (%), and reduced HDL-C.

Associations of ESR1 and ESR2 gene polymorphisms with metabolic syndrome and its components in postmenopausal women

OBJECTIVES

Metabolic syndrome (MS) affects a quarter of Polish people and is associated with diabetes mellitus type 2 and ischemic heart disease. The prevalence of MS in postmenopausal women can be increased by the lack of protective effects of oestrogens. In the near future, because of the general increase in life expectancy, the number of postmenopausal women will rise substantially. Therefore, investigating both the environmental and the genetic factors predisposing to MS may have a great impact on women's health. The aim of this study was to determine whether particular oestrogen receptor (ESR) gene polymorphisms can predispose to the development of MS in women after menopause.

STUDY DESIGN

The sample consisted of 147 postmenopausal women. In addition to collecting medical history and analyzing body composition using the TANITA scale, patient's waist size, blood pressure, serum lipids, glucose, insulin, C-reactive protein and adiponectin were measured. The analysis of ESR gene polymorphisms was performed using the Sequenom MassARRAY platform.

RESULTS

Three out of ten analyzed polymorphisms in the ESR1 gene (rs2234693, rs6902771, rs7774230) and one out of eight analyzed polymorphisms in the ESR2 gene (rs3020449) were associated with MS. The ESR1 rs2234693, rs6902771 and rs7774230 polymorphisms were associated with serum concentrations of high-density lipoproteins. The ESR2 rs3020449 polymorphism was associated with serum concentrations of total cholesterol and low-density lipoprotein. Four ESR1 polymorphisms (rs1709183, rs2234693, rs6902771, rs7774230) were associated with total fat tissue content.

CONCLUSIONS

Bearing the particular alleles at the ESR gene polymorphisms may impact the development of MS and some of the ESR polymorphisms may influence serum cholesterol concentrations in women after menopause.

The effects of oestrogens and their receptors on cardiometabolic health

Cardiovascular disease (CVD) is one of the leading causes of mortality in developed countries. The incidence of CVD is sexually dimorphic, and research has focused on the contribution of sex steroids to the development and progression of the cardiometabolic syndrome, which is defined as a clustering of interrelated risk factors that promote the development of atherosclerosis (which can lead to CVD) and type 2 diabetes mellitus. Data are inconclusive as to how sex steroids and their respective receptors increase or suppress the risk of developing the cardiometabolic syndrome and thus CVD. In this Review, we discuss the potential role, or roles, of sex hormones in cardiometabolic health by first focusing on the influence of oestrogens and their receptors on the risk of developing cardiometabolic syndrome and CVD. We also highlight what is known about testosterone and its potential role in protecting against the development of the cardiometabolic syndrome and CVD. Given the inconclusive nature of the data regarding the direct effects of each sex hormone, we advocate and highlight the importance of studying the relative levels and the ratio of sex hormones to each other, as well as the use of cross sex hormone therapy and its effect on cardiometabolic health.

Sex Hormones and Cardiometabolic Health: Role of Estrogen and Estrogen Receptors

With increased life expectancy, women will spend over three decades of life postmenopause. The menopausal transition increases susceptibility to metabolic diseases such as obesity, diabetes, cardiovascular disease, and cancer. Thus, it is more important than ever to develop effective hormonal treatment strategies to protect aging women. Understanding the role of estrogens, and their biological actions mediated by estrogen receptors (ERs), in the regulation of cardiometabolic health is of paramount importance to discover novel targeted therapeutics. In this brief review, we provide a detailed overview of the literature, from basic science findings to human clinical trial evidence, supporting a protective role of estrogens and their receptors, specifically ERα, in maintenance of cardiometabolic health. In so doing, we provide a concise mechanistic discussion of some of the major tissue-specific roles of estrogens signaling through ERα. Taken together, evidence suggests that targeted, perhaps receptor-specific, hormonal therapies can and should be used to optimize the health of women as they transition through menopause, while reducing the undesired complications that have limited the efficacy and use of traditional hormone replacement interventions.

Identification of polycystic ovary syndrome potential drug targets based on pathobiological similarity in the protein-protein interaction network

Polycystic ovary syndrome (PCOS) is one of the most common endocrinological disorders in reproductive aged women. PCOS and Type 2 Diabetes (T2D) are closely linked in multiple levels and possess high pathobiological similarity. Here, we put forward a new computational approach based on the pathobiological similarity to identify PCOS potential drug target modules (PPDT-Modules) and PCOS potential drug targets in the protein-protein interaction network (PPIN). From the systems level and biological background, 1 PPDT-Module and 22 PCOS potential drug targets were identified, 21 of which were verified by literatures to be associated with the pathogenesis of PCOS. 42 drugs targeting to 13 PCOS potential drug targets were investigated experimentally or clinically for PCOS. Evaluated by independent datasets, the whole PPDT-Module and 22 PCOS potential drug targets could not only reveal the drug response, but also distinguish the statuses between normal and disease. Our identified PPDT-Module and PCOS potential drug targets would shed light on the treatment of PCOS. And our approach would provide valuable insights to research on the pathogenesis and drug response of other diseases.

Polymorphisms in the LPL and CETP Genes and Haplotype in the ESR1 Gene Are Associated with Metabolic Syndrome in Women from Southwestern Mexico

Metabolic syndrome (MetS) is a combination of metabolic disorders associated with an increased risk for cardiovascular disease (CVD). Studies in women reported associations between polymorphisms in ESR1, LPL and CETP genes and MetS. Our aim was to evaluate the association between variants in ESR1, LPL and CETP genes with MetS and its components. Four hundred and eighty women were analyzed, anthropometric features and biochemical profiles were evaluated, and genotyping was performed by real-time PCR. We found an association with elevated glucose levels (odds ratio (OR) = 2.9; p = 0.013) in carrying the AA genotype of rs1884051 in the ESR1 gene compared with the GG genotype, and the CC genotype of rs328 in the LPL gene was associated with MetS compared to the CG or GG genotype (OR = 2.8; p = 0.04). Moreover, the GA genotype of rs708272 in the CETP gene is associated with MetS compared to the GG or AA genotype (OR = 1.8; p = 0.006). In addition the ACTCCG haplotype in the ESR1 gene is associated with a decrease in the risk of MetS (OR = 0.02; p < 0.001). In conclusion, our results show the involvement of the variants of ESR1, LPL and CETP genes in metabolic events related to MetS or some of its features.

MOBAS: identification of disease-associated protein subnetworks using modularity-based scoring

Network-based analyses are commonly used as powerful tools to interpret the findings of genome-wide association studies (GWAS) in a functional context. In particular, identification of disease-associated functional modules, i.e., highly connected protein-protein interaction (PPI) subnetworks with high aggregate disease association, are shown to be promising in uncovering the functional relationships among genes and proteins associated with diseases. An important issue in this regard is the scoring of subnetworks by integrating two quantities: disease association of individual gene products and network connectivity among proteins. Current scoring schemes either disregard the level of connectivity and focus on the aggregate disease association of connected proteins or use a linear combination of these two quantities. However, such scoring schemes may produce arbitrarily large subnetworks which are often not statistically significant or require tuning of parameters that are used to weigh the contributions of network connectivity and disease association.

Here, we propose a parameter-free scoring scheme that aims to score subnetworks by assessing the disease association of interactions between pairs of gene products. We also incorporate the statistical significance of network connectivity and disease association into the scoring function. We test the proposed scoring scheme on a GWAS dataset for two complex diseases type II diabetes (T2D) and psoriasis (PS). Our results suggest that subnetworks identified by commonly used methods may fail tests of statistical significance after correction for multiple hypothesis testing. In contrast, the proposed scoring scheme yields highly significant subnetworks, which contain biologically relevant proteins that cannot be identified by analysis of genome-wide association data alone. We also show that the proposed scoring scheme identifies subnetworks that are reproducible across different cohorts, and it can robustly recover relevant subnetworks at lower sampling rates.

Estrogens prevent metabolic dysfunctions induced by circadian disruptions in female mice

Circadian disruption has become a significant factor contributing to the epidemics of obesity and insulin resistance. However, interventions to treat metabolic dysfunctions induced by circadian disruptions are limited. The ovarian hormone, estrogen, produces important antiobesity and antidiabetic effects in female animals and has profound effects on daily behavioral rhythms. Here, we show that in female mice depleted with endogenous estrogens, a jet-lag paradigm induced visceral fat accumulation and systemic insulin resistance, which were associated with altered expression of multiple circadian genes in the visceral fat depot. Interestingly, all these jet-lag-induced deficits were completely rescued in female mice supplemented with exogenous estrogens. We further examined 24-hour oscillations of circadian genes in adipose tissues in female mice with estrogen depletion or replacement and showed that expression levels of the circadian gene, period circadian protein homolog 2, oscillate in visceral adipose tissue in an estrogen-dependent manner. Together, our results indicate that estrogens interact with the intrinsic circadian clock in adipose tissue and prevent abnormal lipid accumulation caused by circadian disruptions.

Role of developmental transcription factors in white, brown and beige adipose tissues

In this review we discuss the role of developmental transcription factors in adipose tissue biology with a focus on how these developmental genes may contribute to regional variation in adipose tissue distribution and function. Regional, depot-specific, differences in lipid handling and signalling (lipolysis, lipid storage and adipokine/lipokine signalling) are important determinants of metabolic health. At a cellular level, preadipocytes removed from their original depot and cultured in vitro retain depot-specific functional properties, implying that these are intrinsic to the cells and not a function of their environment in situ. High throughput screening has identified a number of developmental transcription factors involved in embryological development, including members of the Homeobox and T-Box gene families, that are strongly differentially expressed between regional white adipose tissue depots and also between brown and white adipose tissue. However, the significance of depot-specific developmental signatures remains unclear. Developmental transcription factors determine body patterning during embryogenesis. The divergent developmental origins of regional adipose tissue depots may explain their differing functional characteristics. There is evidence from human genetics that developmental genes determine adipose tissue distribution: in GWAS studies a number of developmental genes have been identified as being correlated with anthropometric measures of adiposity and fat distribution. Additionally, compelling functional studies have recently implicated developmental genes in both white adipogenesis and the so-called 'browning' of white adipose tissue. Understanding the genetic and developmental pathways in adipose tissue may help uncover novel ways to intervene with the function of adipose tissue in order to promote health.

Endothelial function and insulin resistance in early postmenopausal women with cardiovascular risk factors: importance of ESR1 and NOS3 polymorphisms

Cardiovascular benefits from estradiol activation of nitric oxide endothelial production may depend on vascular wall and on estrogen receptor alpha (ESR1) and nitric oxide synthase (NOS3) polymorphisms. We have evaluated the microcirculation in vivo through nailfold videocapillaroscopy, before and after acute nasal estradiol administration at baseline and after increased sheer stress (postocclusive reactive hyperemia response) in 100 postmenopausal women, being 70 controls (healthy) and 30 simultaneously hypertensive and diabetic (HD), correlating their responses to PvuII and XbaI ESR1 polymorphisms and to VNTR, T-786C and G894T NOS3 variants. In HD women, C variant allele of ESR1 Pvull was associated to higher vasodilatation after estradiol (1.72 vs 1.64 mm/s, p = 0.01 compared to TT homozygotes) while G894T and T-786C NOS3 polymorphisms were connected to lower increment after shear stress (15% among wild type and 10% among variant alleles, p = 0.02 and 0.04). The G variant allele of ESR1 XbaI polymorphism was associated to higher HOMA-IR (3.54 vs. 1.64, p = 0.01) in HD and higher glucose levels in healthy women (91.8 vs. 87.1 mg/dl, p = 0.01), in which increased waist and HOMA-IR were also related to the G allele in NOS3 G894T (waist 93.5 vs 88.2 cm, p = 0.02; HOMA-IR 2.89 vs 1.48, p = 0.05). ESR1 Pvull, NOS3 G894T and T-786C polymorphism analysis may be considered in HD postmenopausal women for endothelial response prediction following estrogen therapy but were not discriminatory for endothelial response in healthy women. ESR1 XbaI and G894T NOS3 polymorphisms may be useful in accessing insulin resistance and type 2 diabetes risks in all women, even before menopause and occurrence of metabolic disease.

Role of hormones in cartilage and joint metabolism: understanding an unhealthy metabolic phenotype in osteoarthritis

OBJECTIVE

Joint health is affected by local and systemic hormones. It is well accepted that systemic factors regulate the metabolism of joint tissues, and that substantial cross-talk between tissues actively contributes to homeostasis. In the current review, we try to define a subtype of osteoarthritis (OA), metabolic OA, which is dependent on an unhealthy phenotype.

METHODS

Peer-reviewed research articles and reviews were reviewed and summarized. Only literature readily available online, either by download or by purchase order, was included.

RESULTS

OA is the most common joint disease and is more common in women after menopause. OA is a disease that affects the whole joint, including cartilage, subchondral bone, synovium, tendons, and muscles. The clinical endpoints of OA are pain and joint space narrowing, which is characterized by cartilage erosion and subchondral sclerosis, suggesting that cartilage is a central tissue of joint health. Thus, the joint, more specifically the cartilage, may be considered a target of endocrine function in addition to the well-described traditional risk factors of disease initiation and progression such as long-term loading of the joint due to obesity. Metabolic syndrome affects a range of tissues and may in part be molecularly described as a dysregulation of cytokines, adipokines, and hormones (e.g., estrogen and thyroid hormone). Consequently, metabolic imbalance may both directly and indirectly influence joint health and cartilage turnover, altering the progression of diseases such as OA.

CONCLUSIONS

There is substantial evidence for a connection between metabolic health and development of OA. We propose that more focus be directed to understanding this connection to improve the management of menopausal health and associated comorbidities.

Estrogen receptor α is not a candidate gene for metabolic syndrome in Caucasian elderly subjects

OBJECTIVE

Variants of estrogen receptor α (ERα) have been associated with obesity, dyslipidemia, diabetes and blood pressure. The Middle East registers some of the highest rate of metabolic syndrome worldwide. The aim of this study is to investigate the relationship between metabolic syndrome, a clustered combination of these metabolic factors, and polymorphisms PvuII and XbaI of ERα in Lebanese Caucasian elderly overweight subjects.

MATERIAL/METHODS

250 Caucasian Lebanese unrelated elderly men and women, median age 71 years, were studied. ERα intronic polymorphisms variants, PvuII and XbaI diplotypes and genotypes, were examined. Associations with metabolic syndrome, defined by the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI), and its components, namely high density lipoprotein (HDL), fasting glucose levels, blood pressure, and waist circumference were evaluated in regression models.

RESULTS

ER α diplotypes and genotypes distributions were similar between participants with and without metabolic syndrome, in the overall group of subjects, and by gender. No consistent associations between the diplotypes and genotypes tested and metabolic syndrome, or its components, could be detected.

CONCLUSIONS

Genetic variants in ERα were not associated with metabolic syndrome or its components, in a group of 250 Lebanese Caucasian elderly participants, a group with a high prevalence of metabolic syndrome.

The role of estrogen in adipose tissue metabolism: insights into glucose homeostasis regulation

Adipose tissue is an organ with active endocrine function involved in the regulation of energy balance and glucose homeostasis via multiple metabolic signaling pathways targeting the brain, liver, skeletal muscle, pancreas, and other organs. There is increasing evidence demonstrating that the female sex hormone, estrogen, regulates adipose development and improves systemic glucose homeostasis in both males and females. The underlying mechanism linking estrogenic regulation in adipose tissue and systemic glucose metabolism has not been fully elucidated, but is thought to include interactions of estrogen receptor signaling events involving lipolytic and/or lipogenic enzyme activity, free fatty acid metabolism, and adipocytokine production. Thus, understanding the effects of estrogen replacement on adipose tissue biology and metabolism is important in determining the risk of developing obesity-related metabolic disorders in patients undergoing treatment for sex hormone deficiency. In this report, we review literature regarding the role of estrogens and their corresponding receptors in the control of adipose metabolism and glucose homeostasis in both rodents and humans. We also discuss the effects of selective estrogen receptor modulators on glucose metabolism.

Associations between polymorphisms in sex steroid related genes and autistic-like traits

Sex differences in psychiatric disorders are common, which is particularly striking in autism spectrum disorders (ASDs) that are four times more prevalent in boys. High levels of testosterone during early development have been hypothesized to be a risk factor for ASDs, supported by several studies showing fetal testosterone levels, as well as indirect measures of prenatal androgenization, to be associated with ASDs and autistic-like traits (ALTs). Further, the importance of sex steroid related genes in ASDs is supported by studies reporting associations between polymorphisms in genes involved in sex steroid synthesis/metabolism and ASDs and ALTs. The aim of the present study was to investigate possible associations between 29 single nucleotide polymorphisms (SNPs) in eight genes related to sex steroids and autistic features. Individuals included in the study belong to a subset (n=1771) from The Child and Adolescent Twin Study in Sweden (CATSS), which are all assessed for ALTs. For two SNPs, rs2747648 located in the 3'-UTR of ESR1 encoding the estrogen receptor alpha and rs523349 (Leu89Val) located in SRD5A2 encoding 5-alpha-reductase, type 2, highly significant associations with ALTs were found in boys and girls, respectively. The results of the present study suggest that SNPs in sex steroid related genes, known to affect gene expression (rs2747648 in ESR1) and enzymatic activity (Leu89Val in SRD5A2), seem to be associated with ALTs in a general population. In conclusion, the current findings provide further support for a role of sex steroids in the pathophysiology of ASDs.

Association of estrogen receptor alpha gene polymorphisms with metabolic syndrome in Egyptian women

OBJECTIVE

Metabolic syndrome is a risk factor for coronary heart diseases as well as diabetes, fatty liver and several cancers. The prevalence of metabolic syndrome in women appears to be increasing, particularly in women of childbearing age. In the present study, we assessed the association of estrogen receptor-alpha gene polymorphisms (XbaI and PvuII) with metabolic syndrome and its related phenotypes.

MATERIALS/METHODS

One hundred and fifty Egyptian female patients with metabolic syndrome (mean age 35.52±6.86) were compared with one hundred and fifty age matched healthy Egyptian women (controls). The component traits of metabolic syndrome were determined, and the XbaI and PvuII genotypes were assessed with the PCR-RFLP method.

RESULTS

Our data indicated a significant difference in the allele frequencies of XbaI, but not PvuII, between the metabolic syndrome and control groups (P=0.0003 and P=0.164). Carriers of the minor alleles of XbaI and PvuII gene polymorphisms, in either the homozygous or heterozygous form, were associated with high diastolic blood pressure, high total cholesterol and LDL-c levels, increased HOMA-IR values and decreased QUICKI values compared to carriers of the major allele. However, only the minor G allele of XbaI was associated with measures of adiposity, specifically, BMI and waist circumference.

CONCLUSIONS

The XbaI polymorphism of the estrogen receptor alpha gene is associated with metabolic syndrome. On the other hand, PvuII gene polymorphism is not associated with the occurrence of the disease in this sample of Egyptian women.

Sex dimorphism and depot differences in adipose tissue function

Obesity, characterized by excessive adiposity, is a risk factor for many metabolic pathologies, such as type 2 diabetes mellitus (T2DM). Numerous studies have shown that adipose tissue distribution may be a greater predictor of metabolic health. Upper-body fat (visceral and subcutaneous abdominal) is commonly associated with the unfavorable complications of obesity, while lower-body fat (gluteal-femoral) may be protective. Current research investigations are focused on analyzing the metabolic properties of adipose tissue, in order to better understand the mechanisms that regulate fat distribution in both men and women. This review will highlight the adipose tissue depot- and sex-dependent differences in white adipose tissue function, including adipogenesis, adipose tissue developmental patterning, the storage and release of fatty acids, and secretory function. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease.

Steroid receptor coactivator-1 mediates estrogenic actions to prevent body weight gain in female mice

Estrogen receptor-α (ERα) expressed by hypothalamic proopiomelanocortin and steroidogenic factor-1 neurons largely mediates the antiobesity effects of estrogens in females. However, the critical molecular events that are coupled to ERα and mediate estrogenic effects on energy balance remain unknown. In the current study, we demonstrated that steroid receptor coactivator-1 (SRC1), a nuclear receptor coactivator, is abundantly expressed by both proopiomelanocortin and steroidogenic factor-1 neurons. We further showed that central administration of an ERα agonist, propyl pyrazole triol, acutely increases physical interaction between SRC1 and ERα in the hypothalamus. Finally, we demonstrated that the effects of estrogens on energy homeostasis are significantly blunted in female mice lacking SRC1 globally. Collectively our results indicate that SRC1 is functionally required to mediate the antiobesity effects of estrogen-ERα signals.

ESR1 gene and insulin resistance remission are associated with serum uric acid decline for severely obese patients undergoing bariatric surgery

BACKGROUND

Hyperuricemia is associated with obesity. Few studies have reported the effects of different types of bariatric surgery on uric acid metabolism. The aim of our study was to determine the relationships between serum uric acid reduction and estrogen receptor-α (ESR1) gene polymorphism, as well as the type of bariatric surgery received. The potential physiological pathways involved in postsurgery serum uric acid reduction were also discussed.

METHODS

A total of 508 severely obese Han Chinese patients, aged 20 to 50 years, with a body mass index (BMI)≥35 kg/m(2) were selected. Patients received either laparoscopic adjustable gastric banding (LAGB; n = 164) or laparoscopic mini-gastric bypass (LMGB; n = 344). A 12-month follow-up was performed to explore the effects of the type of bariatric surgery and ESR1 polymorphism on serum uric acid reduction.

RESULTS

The rs712221 polymorphism of ESR1 affects serum uric acid reduction after bariatric surgery. The LMGB group exhibited a greater reduction in serum uric acid level compared with the LAGB counterpart after adjusting for sex, age, and metabolic confounders (-2.3 ± 2.1 mg/dL versus-1.2 ± 1.1 mg/dL; P = .002). Patients with the rs712221 genotype exhibited better glycemic control and a greater serum uric acid reduction at 12 months after surgery. The effects of the rs712221 polymorphism in LMGB patients resulted in the greatest serum uric acid reduction (-2.7 ± 1.4 mg/dL).

CONCLUSIONS

For severely obese Han Chinese patients, bariatric surgery appears to reduce serum uric acid levels, potentially mediated by synergic effects of surgery type, BMI reduction, rs712221 locus, insulin sensitivity, and changed dietary factors via an unknown mechanism.

The importance of ERα and ERβ gene polymorphisms in PCOS

Estrogens act through binding to estrogen receptor α (ERα) and β (ERβ). Studies in knockout mice have shown that the absence of ERα leads to the polycystic ovary syndrome (PCOS) phenotype. Furthermore, the expression of ERβ gene is lower in follicles derived from women with PCOS compared with healthy women. The aim of this study was to investigate the importance of ERα and ERβ gene polymorphisms in PCOS. A cohort of 180 women with PCOS and 140 healthy controls were recruited, and the PvuII and XbaI polymorphisms of ERα, as well as, the AluI and RsaI polymorphisms of ERβ were genotyped. No difference was found in the distribution of these polymorphisms between patients and healthy controls. However, in PCOS women, carriers of TC and TT genotypes of PvuII polymorphism had lower fasting glucose to insulin ratio compared with carriers of CC genotype (p = 0.029). In addition, the presence of AA genotype of XbaI polymorphism was associated with lower levels of follicle-stimulating hormone (FSH) compared with the presence of AG and GG genotypes (p = 0.03). The association of ERα polymorphisms with insulin resistance indices and FSH levels emphasizes the importance of ERα as a genetic modifier of the PCOS phenotype.

Sex differences in human adipose tissues - the biology of pear shape

Women have more body fat than men, but in contrast to the deleterious metabolic consequences of the central obesity typical of men, the pear-shaped body fat distribution of many women is associated with lower cardiometabolic risk. To understand the mechanisms regulating adiposity and adipose tissue distribution in men and women, significant research attention has focused on comparing adipocyte morphological and metabolic properties, as well as the capacity of preadipocytes derived from different depots for proliferation and differentiation. Available evidence points to possible intrinsic, cell autonomous differences in preadipocytes and adipocytes, as well as modulatory roles for sex steroids, the microenvironment within each adipose tissue, and developmental factors. Gluteal-femoral adipose tissues of women may simply provide a safe lipid reservoir for excess energy, or they may directly regulate systemic metabolism via release of metabolic products or adipokines. We provide a brief overview of the relationship of fat distribution to metabolic health in men and women, and then focus on mechanisms underlying sex differences in adipose tissue biology.

Insulinotropic effect of the non-steroidal compound STX in pancreatic β-cells

The non-steroidal compound STX modulates the hypothalamic control of core body temperature and energy homeostasis. The aim of this work was to study the potential effects of STX on pancreatic β-cell function. 1–10 nM STX produced an increase in glucose-induced insulin secretion in isolated islets from male mice, whereas it had no effect in islets from female mice. This insulinotropic effect of STX was abolished by the anti-estrogen ICI 182,780. STX increased intracellular calcium entry in both whole islets and isolated β-cells, and closed the K_ATP channel, suggesting a direct effect on β-cells. When intraperitoneal glucose tolerance test was performed, a single dose of 100 µg/kg body weight STX improved glucose sensitivity in males, yet it had a slight effect on females. In agreement with the effect on isolated islets, 100 µg/kg dose of STX enhanced the plasma insulin increase in response to a glucose load, while it did not in females. Long-term treatment (100 µg/kg, 6 days) of male mice with STX did not alter body weight, fasting glucose, glucose sensitivity or islet insulin content. Ovariectomized females were insensitive to STX (100 µg/kg), after either an acute administration or a 6-day treatment. This long-term treatment was also ineffective in a mouse model of mild diabetes. Therefore, STX appears to have a gender-specific effect on blood glucose homeostasis, which is only manifested after an acute administration. The insulinotropic effect of STX in pancreatic β-cells is mediated by the closure of the K_ATP channel and the increase in intracellular calcium concentration. The in vivo improvement in glucose tolerance appears to be mostly due to the enhancement of insulin secretion from β-cells.

Association between ESR1 rs1884051 polymorphism and dietary total energy and plant protein intake on obesity in Korean men

ESR1 has been listed in the Human Obesity Gene Map as candidate gene associated with obesity. Thus, in this study, we investigated the effect of the ESR1 rs1884051 polymorphism on obesity-related variables, together with their modulations by dietary intake in Korean men. The obesity-related variables and dietary intake of 3,039 Korean men aged 40-59 years from KoGES database were analyzed. Body weight (P = 0.007), BMI (P = 0.003), waist-hip ratio (= 0.011), fat body mass (P = 0.010), and body fat percentage (P = 0.040) were significantly lower in subjects with the minor T allele of ESR1 rs1884051 than in subjects carrying the C allele. Moreover, the rs1884051 T allele was associated with a decreased risk of obesity prevalence (P = 0.040). Among the subjects whose total energy intake was below the median, carrier of the minor T allele of ESR1 rs1884051 had a lower BMI (P = 0.003) when compared with subjects carrying the C allele. In addition, among subjects whose plant protein intake was above the median, carrier of the minor T allele of ESR1 rs1884051 had a lower BMI (P = 0.044) compared with subjects carrying the C allele. Our findings demonstrate that there is a significant association between the ESR1 rs1884051 variant and obesity-related variables and this association can be potentially modified by dietary energy and plant protein intake.

Urinary bisphenol A and type-2 diabetes in U.S. adults: data from NHANES 2003-2008

OBJECTIVE

Bisphenol A (BPA) is found in plastics and other consumer products; exposure may lead to insulin resistance and development of type-2 diabetes mellitus (T2DM) through over-activation of pancreatic β-cells. Previous studies using data from the National Health and Nutrition Examination Survey (NHANES) showed an inconsistent association between prevalence of self-reported T2DM and urinary BPA. We used a different diagnosis method of T2DM (hemoglobin A1c (HbA1c)) with a larger subset of NHANES.

METHODS AND FINDINGS

We analyzed data from 4,389 adult participants who were part of a sub-study of environmental phenol measurements in urine from three NHANES cycles from 2003 to 2008. T2DM was defined as having a HbA1c ≥ 6.5% or use of diabetes medication. The weighted prevalence of T2DM was 9.2%. Analysis of the total sample revealed that a two-fold increase in urinary BPA was associated with an odds ratio (OR) of 1.08 of T2DM (95% confidence interval (CI), 1.02 to 1.16), after controlling for potential confounders. However, when we examined each NHANES cycle individually, we only found a statistically significant association in the 2003/04 cycle (n = 1,364, OR = 1.23 (95% CI, 1.07 to 1.42) for each doubling in urinary BPA). We found no association in either the NHANES cycle from 2005/06 (n = 1,363, OR = 1.05 (95% CI, 0.94 to 1.18)); or 2007/08 (n = 1,662, OR = 1.06 (95% CI, 0.91 to 1.23)). Similar patterns of associations between BPA and continuous HbA1c were also observed.

CONCLUSIONS

Although higher urinary BPA was associated with elevated HbA1c and T2DM in the pooled analysis, it was driven by data from only one NHANES cycle. Additional studies, especially of a longitudinal design with repeated BPA measurements, are needed to further elucidate the association between BPA and T2DM.

Identification of candidate genes related to bovine marbling using protein-protein interaction networks

Complex traits are determined by the combined effects of many loci and are affected by gene networks or biological pathways. Systems biology approaches have an important role in the identification of candidate genes related to complex diseases or traits at the system level. The present study systemically analyzed genes associated with bovine marbling score and identified their relationships. The candidate nodes were obtained using MedScan text-mining tools and linked by protein-protein interaction (PPI) from the Human Protein Reference Database (HPRD). To determine key node of marbling, the degree and betweenness centrality (BC) were used. The hub nodes and biological pathways of our network are consistent with the previous reports about marbling traits, and also suggest unknown candidate genes associated with intramuscular fat. Five nodes were identified as hub genes, which was consistent with the network analysis using quantitative reverse-transcription PCR (qRT-PCR). Key nodes of the PPI network have positive roles (PPARγ, C/EBPα, and RUNX1T1) and negative roles (RXRA, CAMK2A) in the development of intramuscular fat by several adipogenesis-related pathways. This study provides genetic information for identifying candidate genes for the marbling trait in bovine.

Estrogen receptor alpha gene polymorphisms are associated with type 2 diabetes and fasting glucose in male subjects

The PvuII and XbaI polymorphisms of the estrogen receptor α (ER1) gene have been variably associated with type 2 diabetes (T2D) in several populations. However, this association has not been studied in Iranian subjects and we hypothesized that the ER1 variants might be associated with T2D and related metabolic traits in this population. The PvuII and XbaI genotypes were determined by PCR-RFLP in 377 normoglycemic controls and 155 T2D patients. Bonferroni correction was applied for the correction of multiple testing. No significant association was found between the allele and genotype frequencies of PvuII and XbaI variants with T2D in females. In a dominant model (PP vs. Pp+pp), the frequency of the Pp+pp genotype was higher in normoglycemic subjects compared to T2D patients [85.5% vs. 66.7%, OR 0.22 (0.08-0.55), P=0.001]. Four possible haplotypes were observed in the population, whereas haplotype TA had a higher frequency in male T2D subjects than the controls. Furthermore, non-diabetic male subjects carrying the genotype of PP had a higher fasting glucose levels than the individuals with the genotype of Pp+pp (P=0.013). Multivariate logistic regression analysis showed that PvuII polymorphism was the independent determinants of T2D in males [OR 4.37 (1.61-11.86), P=0.004]. No association was found between the XbaI polymorphism and diabetes in male group. Our results suggest that the ER1 polymorphisms might associate with T2D and fasting glucose among Iranian male subjects.

The association between the rs2234693 and rs9340799 estrogen receptor alpha gene polymorphisms and risk factors for cardiovascular disease: a review

Although estrogen is primarily thought of as the hormone involved in female reproduction, it also plays a role in many additional physiological and pathological processes. Recent studies have demonstrated an association between estrogen and clustered risk factors for cardiovascular disease (CVD), such as lipid and glucose metabolism and obesity-related phenotypes, as well as occurrence and severity of CVD. Evidence suggesting a genetic basis for this link is accumulating. Several polymorphisms of the estrogen receptor (ER) alpha (ESR1) gene exist that may influence the impact of estrogen, leading to clinically relevant phenotypes. Based on the relationship ERS1 seems to exhibit with CVD risk factors, these polymorphisms may play a role in the mediation of vasoprotective effects, modulation of cardiovascular physiology, and development of risk factors for CVD. The two most frequently studied polymorphisms located in ESR1 are often identified by their restriction endonucleases Pvull (rs2234693) and Xbal (rs9340799). ln this review, we have evaluated and summarized the results of studies involving rs2234693 and rs9340799 and clustered risk factors accompanying development of CVD. Despite inconsistent findings, together these studies provide some support for a relationship between polymorphisms in ESR1 and risk factors for CVD. These summarized findings do not yet support inclusion of ESR1 genotypes in genetic testing algorithms for predisposition to CVD, but they do indicate that further investigation into the potential connection between ESR1 and risk factors for CVD is warranted.

Association analysis of genetic polymorphisms and potential interaction of the osteocalcin (BGP) and ER-alpha genes with body mass index (BMI) in premenopausal Chinese women

AIM

To investigate whether estrogen receptor alpha (ER-alpha) PvuII and osteocalcin (also known as bone Gla protein, or BGP) HindIII genetic polymorphisms and their potential interactions are associated with body mass index (BMI) variation.

METHODS

Data on BMI and ER-alpha PvuII and BGP HindIII genotypes were obtained from 328 healthy premenopausal Chinese women in east China. The study subjects were unrelated, at least 21 years old (mean age of 33.2+/-5.9 years), and had an average BMI of 21.58+/-2.59. All subjects were genotyped at the ER-alpha PvuII and BGP HindIII loci using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP).

RESULTS

The BGP HindIII genotypes were significantly associated with BMI (P=0.003). Carriers of the HH and Hh genotypes had approximately 2.73% and 1.27% higher BMI than those of the hh genotype, respectively. In contrast, the ER-alpha PvuII polymorphism was not significantly associated with BMI (P=0.454). In addition, there was no evidence of potential interactions between the ER-alpha and BGP genes in our subjects (P>or=0.013).

CONCLUSION

The HindIII polymorphism of the BGP gene, but not the PvuII polymorphism of the ER-alpha gene or their potential interaction, was associated with BMI in premenopausal Chinese women.

Bisphenol-A: a new diabetogenic factor?

The aim of this review was to analyze the potential effects of environmental chemicals on homeostatic control related to glycemia and energy balance. Many of the environmental chemicals can mimic or interfere with the action of hormones and are generally referred to as "endocrine disruptors". Among these compounds, polychlorinated biphenyls, dioxins, phthalates and bisphenol-A have been correlated with alterations in blood glucose homeostasis in humans. In rodents it has been demonstrated that small doses of bisphenol-A have profound effects on glucose metabolism. Therefore, this altered blood glucose homeostasis may enhance the development of type 2 diabetes.

Polymorphisms of estrogen receptors and risk of biliary tract cancers and gallstones: a population-based study in Shanghai, China

Biliary tract cancer encompasses tumors of the gallbladder, bile duct and ampulla of Vater. Gallbladder cancer is more common in women, whereas bile duct cancer is more common in men, suggesting that sex hormones may play a role in the etiology of these cancers. The intracellular action of estrogens is regulated by the estrogen receptor (ESR); thus, we examined the role of common genetic variants in ESR genes on the risk of biliary tract cancers and stones in a population-based case-control study in Shanghai, China (411 cancer cases, 895 stone cases and 786 controls). We genotyped six single-nucleotide polymorphisms (SNPs), four in ESR1 (rs2234693, rs3841686, rs2228480 and rs1801132) and two in ESR2 (rs1256049 and rs4986938). In all participants, the ESR1 rs1801132 (P325P) G allele was associated with excess risks of bile duct [odds ratio (OR) = 1.7, 95% confidence interval (CI) 1.1-2.8] and ampulla of Vater cancers (OR = 2.1, 95% CI 0.9-4.9) compared with the CC genotype. The association with bile duct cancer was apparent among men (OR = 2.8, 95% CI 1.4-5.7) but not among women (P-heterogeneity = 0.01). Also, the ESR2 rs4986938 (38 bp 3' of STP) GG genotype was associated with a higher risk of bile duct cancer (OR = 3.3, 95% CI 1.3-8.7) compared with the AA genotype, although this estimate was based on a small number of subjects. None of the other SNPs examined was associated with biliary tract cancers or stones. False discovery rate-adjusted P-values were not significant (P > 0.1). No association was found for ESR1 haplotype based on four SNPs. These preliminary results suggest that variants in ESR genes could play a role in the etiology of biliary tract cancers, especially bile duct cancer in men.

Emerging role of estrogen in the control of cardiometabolic disease

Menopause is associated with an increased risk of cardiovascular and metabolic disease that is partly independent of aging. This increased risk is largely due to postmenopausal estrogen loss. Estrogen improves insulin sensitivity and ss-cell function. This is consistent with the increased risk of diabetes after menopause and the finding that menopausal hormone therapy (MHT) lowers the incidence of diabetes. Experimental data suggest that estrogen has anti-atherosclerotic and pro-thrombotic properties. This is consistent with observational and interventional studies suggesting that MHT reduces the risk of cardiovascular disease if initiated early in women with a low-risk profile, but might increase risk in older women and/or those with other risk factors (e.g. dyslipidemia). Future research focusing on improving prevention of cardiometabolic disease through MHT may help to identify agents with higher tissue- and estrogen receptor-isoform specificity than currently used hormones.

Gene expression profiling of the short-term adaptive response to acute caloric restriction in liver and adipose tissues of pigs differing in feed efficiency

Residual feed intake (RFI) is a measure of feed efficiency, in which low RFI denotes improved feed efficiency. Caloric restriction (CR) is associated with feed efficiency in livestock species and to human health benefits, such as longevity and cancer prevention. We have developed pig lines that differ in RFI, and we are interested in identifying the genes and pathways that underlie feed efficiency. Prepubertal Yorkshire gilts with low RFI (n = 10) or high RFI (n = 10) were fed ad libitum or fed at restricted intake of 80% of maintenance energy requirements for 8 days. We measured serum metabolites and hormones and generated transcriptional profiles of liver and subcutaneous adipose tissue on these animals. Overall, 6,114 genes in fat and 305 genes in liver were differentially expressed (DE) in response to CR, and 311 genes in fat and 147 genes in liver were DE due to RFI differences. Pathway analyses of CR-induced DE genes indicated a dramatic switch to a conservation mode of energy usage by down-regulating lipogenesis and steroidogenesis in both liver and fat. Interestingly, CR altered expression of genes in immune and cell cycle/apoptotic pathways in fat, which may explain part of the CR-driven lifespan enhancement. In silico analysis of transcription factors revealed ESR1 as a putative regulator of the adaptive response to CR, as several targets of ESR1 in our DE fat genes were annotated as cell cycle/apoptosis genes. The lipid metabolic pathway was overrepresented by down-regulated genes due to both CR and low RFI. We propose a common energy conservation mechanism, which may be controlled by PPARA, PPARG, and/or CREB in both CR and feed-efficient pigs.

QTL for several metabolic traits map to loci controlling growth and body composition in an F2 intercross between high- and low-growth chicken lines

Quantitative trait loci (QTL) for metabolic and body composition traits were mapped at 7 and 9 wk, respectively, in an F2 intercross between high-growth and low-growth chicken lines. These lines also diverged for abdominal fat percentage (AFP) and plasma insulin-like growth factor-I (IGF-I), insulin, and glucose levels. Genotypings were performed with 129 microsatellite markers covering 21 chromosomes. A total of 21 QTL with genomewide level of significance were detected by single-trait analyses for body weight (BW), breast muscle weight (BMW) and percentage (BMP), AF weight (AFW) and percentage (AFP), shank length (ShL) and diameter (ShD), fasting plasma glucose level (Gluc), and body temperature (Tb). Other suggestive QTL were identified for these parameters and for plasma IGF-I and nonesterified fatty acid levels. QTL controlling adiposity and Gluc were colocalized on GGA3 and GGA5 and QTL for BW, ShL and ShD, adiposity, and Tb on GGA4. Multitrait analyses revealed two QTL controlling Gluc and AFP on GGA5 and Gluc and Tb on GGA26. Significant effects of the reciprocal cross were observed on BW, ShD, BMW, and Gluc, which may result from mtDNA and/or maternal effects. Most QTL regions for Gluc and adiposity harbor genes for which alleles have been associated with increased susceptibility to diabetes and/or obesity in humans. Identification of genes responsible for these metabolic QTL will increase our understanding of the constitutive “hyperglycemia” found in chickens. Furthermore, a comparative approach could provide new information on the genetic causes of diabetes and obesity in humans.

Associations of the estrogen receptors 1 and 2 gene polymorphisms with the metabolic syndrome in women

BACKGROUND

Genetic variation of the estrogen receptor alpha (ESR1) and beta (ESR2) has been associated with components of the metabolic syndrome.

METHODS

The relationships of two ESR1 (rs2234693 and rs9340799) and three ESR2 (rs1271572, rs1256049, and rs4986938) polymorphisms with the metabolic syndrome were examined in 532 Caucasian female participants (median age 63.1 years) in the Women's Health Study. Most women (99.1%) were postmenopausal. The associations between ESR1 and ESR2 genotypes and haplotypes with the metabolic syndrome were evaluated. Effect modification by hormone therapy was also assessed.

RESULTS

Genotype and haplotype distributions were similar between women with and without metabolic syndrome. We found no consistent associations between the genotypes and haplotypes tested and the metabolic syndrome, or its components, in logistic regression models. No effect modification by hormone therapy use was noted.

CONCLUSIONS

No association between these genetic variants in ESR1 and ESR2 and the metabolic syndrome was observed among these Caucasian women. Further investigation regarding the potential involvement of estrogen receptor genes and the metabolic syndrome may be warranted in other ethnic groups.

Association of ER-alpha gene polymorphism with metabolic phenotypes in Chinese Hans

Recently, two polymorphisms (rs1884052 and rs3778099) of estrogen receptor alpha (ER-alpha) gene were identified as being associated with primary quantitative bone mineral density (BMD) in a genome-wide association (GWA) study in Framingham cohorts. In this study we aimed at investigating the association of rs1884052 and rs3778099, and another polymorphism (rs2234693) located at intron 1 of the ER-alpha gene with BMD, body mass index (BMI), glucose, triglyceride, and total cholesterol (CHO) levels in Chinese Hans. We recruited 425 consecutive adult volunteers who had a physical examination in the Jinan Maternity and Child Care Hospital. We did not observe significant association of rs1884052 and rs3778099 with BMD, BMI, glucose, triglyceride, and total cholesterol (CHO) levels. For rs2234693, increased levels of BMD for hip, spine or whole-body regions were consistently observed in TT/TC genotype carriers than in CC genotype carriers, although the board line significance diminished after adjusting for age and gender. However, significant association of rs2234693 with glucose and CHO levels were observed in our sample. Subjects with TC/CC genotypes were associated with an increased level of glucose (p = 0.013) and CHO (p = 0.032) levels than subjects with TT genotypes. In conclusion, we did not confirm the association of rs1884052 and rs3778099 with BMD originally discovered in a GWA study; however, we made novel discoveries that rs2234693 was associated with glucose and CHO levels in Chinese Hans.

Association of polymorphism of estrogen receptor-alpha gene with circulating levels of adiponectin in postmenopausal women with type 2 diabetes

AIM

Menopause is a risk factor for cardiovascular disease (CVD) in women because of the reduction in endogenous estrogen. Recently, single nucleotide polymorphisms (SNPs) of the estrogen receptor alpha (ESR-1) gene (c.454-397T>C) associated with the prognosis of myocardial infarction in postmenopausal women were identified; however, the mechanism by which genetic variation of ESR-1 contributes to the pathogenesis of CVD is unknown. Circulating levels of adipokines and inflammatory cytokines predict CVD risk; hence, this study aimed to investigate whether ESR-1 genotypes (c.454-397T>C) might influence circulating levels of adipokines and inflammatory cytokines in postmenopausal women with type 2 diabetes.

METHODS

Sixty-three postmenopausal women with type 2 diabetes were recruited. Serum levels of adiponectin, resistin, interleukin-6 (IL-6), and high-sensitive C-reactive protein (hs-CRP) were determined.

RESULTS

The genotype of ESR-1 was closely associated with serum adiponectin, which was decreased in subjects with the T allele and was lowest in those with the T/T genotype. Multiple logistic regression analysis revealed independent contribution of the homozygote for the T allele to low serum levels of adiponectin.

CONCLUSION

The T allele of the c.454-397T>C SNP of ESR-1 is associated with low serum levels of adiponectin, which may lead to a high risk of CVD in postmenopausal women.

Microarray gene expression profiles of fasting induced changes in liver and adipose tissues of pigs expressing the melanocortin-4 receptor D298N variant

Transcriptional profiling coupled with blood metabolite analyses were used to identify porcine genes and pathways that respond to a fasting treatment or to a D298N missense mutation in the melanocortin-4 receptor (MC4R) gene. Gilts (12 homozygous for D298 and 12 homozygous for N298) were either fed ad libitum or fasted for 3 days. Fasting decreased body weight, backfat, and serum urea concentration and increased serum nonesterified fatty acid. In response to fasting, 7,029 genes in fat and 1,831 genes in liver were differentially expressed (DE). MC4R genotype did not significantly affect gene expression, body weight, backfat depth, or any measured serum metabolite concentration. Pathway analyses of fasting-induced DE genes indicated that lipid and steroid synthesis was downregulated in both liver and fat. Fasting increased expression of genes involved in glucose sparing pathways, such as oxidation of amino acids and fatty acids in liver, and in extracellular matrix pathways, such as cell adhesion and adherens junction in fat. Additionally, we identified DE transcription factors (TF) that regulate many DE genes. This confirms the involvement of TF, such as PPARG, SREBF1, and CEBPA, which are known to regulate the fasting response, and implicates additional TF, such as ESR1. Interestingly, ESR1 controls several fasting induced genes in fat that are involved in cell matrix morphogenesis. Our findings indicate a transcriptional response to fasting in two key metabolic tissues of pigs, which was corroborated by changes in blood metabolites, and the involvement of novel putative transcriptional regulators in the immediate adaptive response to fasting.

Do Genetic Alterations in Sex Steroid Receptors Contribute to Lacrimal Gland Disease in Sjögren's Syndrome?

BACKGROUND: Defects in sex steroid receptors have been linked to the onset, progression and severity, as well as the sex-related prevalence, of a variety of autoimmune disorders, including lupus, rheumatoid arthritis, multiple sclerosis and diabetes. We hypothesize that defects in estrogen receptor alpha (ESR1), estrogen receptor beta (ESR2) and/or the androgen receptor (AR) may also contribute to the development of lacrimal gland autoimmune sequelae in Sjögren's syndrome. To begin to test this hypothesis, we examined whether mutations exist in the coding regions of ESR1, ESR2 and AR transcripts in lacrimal tissues of mouse models of Sjögren's syndrome. METHODS: Lacrimal and submandibular glands were collected from adult MRL/MpJ-Tnfrsf6(lpr), nonobese diabetic and/or BALB/c mice. Tissues were pooled according to sex and experiment and processed for cDNA generation. PCR primers were designed to amplify 566-875 base pair segments of the entire open reading frame of each receptor. Segments were amplified, purified and then sequenced. Receptor sequences were assembled and compared to each other and to known NCBI sequences. RESULTS: Our results show that almost all ESR1, ESR2 and AR sequences in exocrine tissues of male and female autoimmune and non-autoimmune mice were identical to those of NCBI standards. There was a G-->A shift at position 998 of the ESR2 complete coding sequence in all tissue samples when compared to NCBI reference sequence U81451.1, but this polymorphism was not found in other ESR2 reference sequences. CONCLUSIONS: Our findings indicate that defects in the coding region of sex steroid receptors do not contribute to the pathogenesis of lacrimal gland disease in mouse models of Sjögren's syndrome.

Activation of estrogen receptor is crucial for resveratrol-stimulating muscular glucose uptake via both insulin-dependent and -independent pathways

OBJECTIVE

Estradiol (E(2)) is known to modulate insulin sensitivity and, consequently, glucose homeostasis. Resveratrol (RSV), an agonist of estrogen receptor (ER), has exerted antihyperglycemic effects in streptozotocin-induced type 1 diabetic rats in our previous study and was also shown to improve insulin resistance in other reports. However, it remains unknown whether activation of ER is involved in the metabolic effects of RSV via insulin-dependent and -independent mechanisms.

RESEARCH DESIGN AND METHODS

Male Sprague-Dawley rats were given a high cholesterol-fructose (HCF) diet for 15 weeks and were treated with RSV for either 15 days or 15 weeks.

RESULTS

Here, we show that RSV shifts the metabolic characteristics of rats on an HCF diet toward those of rats on a standard diet. RSV treatment increased insulin-stimulated whole-body glucose uptake and steady-state glucose uptake of soleus muscle and liver in HCF-fed rats as well as enhanced membrane trafficking activity of GLUT4 and increased phosphorylation of insulin receptor in insulin-resistant soleus muscles. Interestingly, the phosphorylated ER level in insulin-resistant soleus muscle was significantly elevated in rats with RSV treatment in both basal and euglycemic-hyperinsulinemic conditions. RSV exerted an insulin-like stimulatory effect on isolated soleus muscle, epididymal fat and hepatic tissue, and C2C12 myotubes. The RSV-stimulated glucose uptake in C2C12 myotubes was dependent on extracellular signal-related kinase/p38 (early phase, 1 h) and p38/phosphoinositide 3-kinase (late phase, 14 h) activation. Inhibition of ER abrogated RSV-induced glucose uptake in both early and late phases.

CONCLUSIONS

Collectively, these results indicate that ER is a key regulator in RSV-stimulating insulin-dependent and -independent glucose uptake, which might account for the protective effects of RSV on diet-induced insulin resistance syndrome.

Evaluation of a SNP map of 6q24-27 confirms diabetic nephropathy loci and identifies novel associations in type 2 diabetes patients with nephropathy from an African-American population

Previously, we performed a genome scan for type 2 diabetes (T2DM) using 638 African-American (AA) affected sibling pairs from 247 families; non-parametric linkage analysis suggested evidence of linkage at 6q24-27 (LOD 2.26). To comprehensively evaluate this region, we performed a two-stage association study by first constructing a SNP map of 754 SNPs selected from HapMap on the basis of linkage disequilibrium (LD) in 300 AAT2DM end-stage renal disease (ESRD) subjects, 311 AA controls, 43 European American controls and 45 Yoruba Nigerian samples (Set 1). Replication analyses were conducted in an independent population of 283 AA T2DM-ESRD subjects and 282 AA controls (Set 2). In addition, we adjusted for the impact of admixture on association results by using ancestry informative markers (AIMs). In Stage 1, 137 (18.2%) SNPs showed nominal evidence of association (P < 0.05) in one or more of tests of association: allelic (n = 33), dominant (n = 36), additive (n = 29), or recessive (n = 34) genotypic models, and 2- (n = 47) and 3-SNP (n = 43) haplotypic analyses. These SNPs were selected for follow-up genotyping. Stage 2 analyses confirmed association with a predicted 2-SNP "risk" haplotype in the PARK2 gene. Also, two intergenic SNPs showed consistent genotypic association with T2DM-ESRD: rs12197043 and rs4897081. Combined analysis of all subjects from both stages revealed nominal associations with 17 SNPs within genes, including suggestive associations in ESR1 and PARK2. This study confirms known diabetic nephropathy loci and identifies potentially novel susceptibility variants located within 6q24-27 in AA.