Association of obesity, but not diabetes or hypertension, with glucocorticoid receptor N363S variant

The Glucocorticoid Receptor: Isoforms, Functions, and Contribution to Glucocorticoid Sensitivity

Glucocorticoids exert pleiotropic effects on all tissues to regulate cellular and metabolic homeostasis. Synthetic forms are used therapeutically in a wide range of conditions for their anti-inflammatory benefits, at the cost of dose and duration-dependent side effects. Significant variability occurs between tissues, disease states, and individuals with regard to both the beneficial and deleterious effects. The glucocorticoid receptor (GR) is the site of action for these hormones and a vast body of work has been conducted understanding its function. Traditionally, it was thought that the anti-inflammatory benefits of glucocorticoids were mediated by transrepression of pro-inflammatory transcription factors, while the adverse metabolic effects resulted from direct transactivation. This canonical understanding of the GR function has been brought into question over the past 2 decades with advances in the resolution of scientific techniques, and the discovery of multiple isoforms of the receptor present in most tissues. Here we review the structure and function of the GR, the nature of the receptor isoforms, and the contribution of the receptor to glucocorticoid sensitivity, or resistance in health and disease.

The Anti-Obesogenic Effects of Muscadine Grapes through Ciliary Neurotrophic Factor Receptor (Cntfr) and Histamine Receptor H1 (Hrh1) Genes in 3T3-L1 Differentiated Mouse Cells

Obesity and type 2 diabetes are prevalent metabolic diseases that have significant links to several chronic diseases, including cancer, diabetes, hypertension, and cardiovascular disease. Muscadine grape extracts have shown the potential to reduce adiposity and improve insulin sensitivity and glucose control. Thus, this study was designed to determine the potential of muscadine grape berries extract (Pineapple and Southern Home) for its antiobesity properties in 3T3-L1 cells as a model for obesity research. The current study's data indicated the total phenolic content (TPC) and 2,2-diphenyl-1-picrylhydraziyl (DPPH) activity were higher in cultivar (CV) Southern Home, meanwhile, elevated the total flavonoid content (TFC) in Pineapple. Both extracts were safe across the tested range (0-5 mg/mL). A noticeable reduction in lipid accumulation was also found in extract-treated cells. In preadipocytes and adipocytes, the tested extracts showed significant alterations in various genes involved in glucose homeostasis and obesity. The most remarkable findings of the current study are the upregulation of two genes, Cntfr (+712.715-fold) and Hrh1 (+270.11-fold) in CV Pineapple extract-treated adipocytes 3T3-L1 and the high fold increase in Ramp3 induced by both Pineapple and Southern Home in pre-adipose cells. Furthermore, the tested extracts showed a potential to alter the mRNA of various genes, including Zfp91, B2m, Nr3c1, Insr, Atrn, Il6ra, Hsp90ab1, Sort1, and Npy1r. In conclusion, the data generated from the current study suggested that the two extracts under investigation are considered potential candidates for controlling insulin levels and managing obesity.

Variation in glucocorticoid sensitivity and the relation with obesity

Increasing evidence points to a relation between increased glucocorticoid (GC) exposure and weight gain. In support, long-term cortisol measurements using hair analysis revealed that many individuals with obesity appear to have cortisol values in the high physiological range. The mechanisms behind this relationship need to be determined in order to develop targeted therapy to reach sustainable weight loss in these subgroups. The effect of GCs is not only determined by the plasma concentration of GCs but also by individual differences in GC sensitivity and the target tissue, which can be analyzed by functional GC assays. GC sensitivity is influenced by multiple genetic and acquired (e.g., disease-related) factors, including intracellular GC availability, hormone binding affinity, and expression levels of the GC receptors and their isoforms, as well as factors involved in the modulation of gene transcription. Interindividual differences in GC sensitivity also play a role in the response to exogenous GCs, with respect to both therapeutic and adverse effects. Accordingly, in this review, we summarize current knowledge on mechanisms that influence GC sensitivity and their relationships with obesity and discuss personalized treatment options targeting the GC receptor.

The clinical significance of the glucocorticoid receptors: Genetics and epigenetics

The impacts of glucocorticoids (GCs) are mainly mediated by a nuclear receptor (GR) existing in almost every tissue. The GR regulates a wide range of physiological functions, including inflammation, cell metabolism, and differentiation playing a major role in cellular responses to GCs and stress. Therefore, the dysregulation or disruption of GR can cause deficiencies in the adaptation to stress and the preservation of homeostasis. The number of GR polymorphisms associated with different diseases has been mounting per year. Tackling these clinical complications obliges a comprehensive understanding of the molecular network action of GCs at the level of the GR structure and its signaling pathways. Beyond genetic variation in the GR gene, epigenetic changes can enhance our understanding of causal factors involved in the development of diseases and identifying biomarkers. In this review, we highlight the relationships of GC receptor gene polymorphisms and epigenetics with different diseases.

Glucocorticoid induced adrenal insufficiency

Synthetic glucocorticoids are widely used for their anti-inflammatory and immunosuppressive actions. A possible unwanted effect of glucocorticoid treatment is suppression of the hypothalamic-pituitary-adrenal axis, which can lead to adrenal insufficiency. Factors affecting the risk of glucocorticoid induced adrenal insufficiency (GI-AI) include the duration of glucocorticoid therapy, mode of administration, glucocorticoid dose and potency, concomitant drugs that interfere with glucocorticoid metabolism, and individual susceptibility. Patients with exogenous glucocorticoid use may develop features of Cushing's syndrome and, subsequently, glucocorticoid withdrawal syndrome when the treatment is tapered down. Symptoms of glucocorticoid withdrawal can overlap with those of the underlying disorder, as well as of GI-AI. A careful approach to the glucocorticoid taper and appropriate patient counseling are needed to assure a successful taper. Glucocorticoid therapy should not be completely stopped until recovery of adrenal function is achieved. In this review, we discuss the factors affecting the risk of GI-AI, propose a regimen for the glucocorticoid taper, and make suggestions for assessment of adrenal function recovery. We also describe current gaps in the management of patients with GI-AI and make suggestions for an approach to the glucocorticoid withdrawal syndrome, chronic management of glucocorticoid therapy, and education on GI-AI for patients and providers.

Generalized and tissue specific glucocorticoid resistance

Glucocorticoids (GCs) are steroid hormones that influence several physiologic functions and are among the most frequently prescribed drugs worldwide. Resistance to GCs has been observed in the context of the familial generalized GC resistance (Chrousos' syndrome) or tissue specific GC resistance in chronic inflammatory states. In this review, we have summarized the major factors that influence individual glucocorticoid sensitivity/resistance. The fine-tuning of GC action is determined in a tissue-specific fashion that includes the combination of different GC receptor promoters, translation initiation sites, splice isoforms, interacting proteins, post-translational modifications, and alternative mechanisms of signal transduction.

Serum cortisone and glucocorticoid receptor gene (NR3C1) polymorphism in human dysglycemia

PURPOSE

We aimed to explore the associations of serum cortisone and glucocorticoid receptor (GR) polymorphism with glucose metabolism and type 2 diabetes mellitus (T2DM) among Chinese adults.

METHODS

A total of 2315 participants were included in the present study. Serum cortisone was measured by liquid chromatography-tandem mass spectrometry. Multivariable logistic regression and linear regression were employed to assess the associations between serum cortisone and different glucose metabolism status.

RESULTS

Serum cortisone was positively associated with impaired fasting glucose (IFG) and T2DM ((Quartile 4 vs Quartile 1, odds ratio (OR) = 1.36, 95% confidence interval (CI) 1.01, 1.84, and OR = 2.08, 95% CI 1.50, 2.89, respectively)). A 100% increase in cortisone was associated with a 0.015 (95% CI 0.005, 0.025) mg/dl higher fasting plasma glucose (FPG), a 0.007 (95% CI 0.001, 0.013) higher glycosylated hemoglobin (HbA1c), a 0.4% (95% CI - 0.007, 0.000) lower HOMA2-IR, and a 58.1% (95% CI - 0.788, - 0.373) lower HOMA2-β. After stratification by genotype, the association between serum cortisone and T2DM was not significant in TT genotype carriers. In addition, at the higher concentrations of cortisone, TT genotype carriers had a lower FPG, HbA1c, and HOMA2-IR and a higher HOMA2-β than GG and GT carriers.

CONCLUSIONS

Elevated serum cortisone was associated with an increased risk of IFG and T2DM, and the associations may be modified by rs9324924 polymorphism.

Glucocorticoid Receptor Polymorphisms Influence Muscle Strength in Cushing's Syndrome

CONTEXT

An important clinical feature of Cushing's syndrome (CS) is proximal muscle myopathy caused by glucocorticoid induced protein metabolism. However, interindividual differences cannot be explained solely by the pure extent of hypercortisolemia.

OBJECTIVE

To evaluate the effects of glucocorticoid receptor (GR) polymorphisms (BclI, N363S, ER22/23EK and A3669G), which influence peripheral glucocorticoid sensitivity on muscular function in endogenous CS.

METHODS

205 patients with proven endogenous CS (128 central, 77 adrenal) from 3 centers of the German Cushing's Registry and 125 subjects, in whom CS was ruled out, were included. All subjects were assessed for grip strength (via hand grip dynamometer) and performed a chair-rising test (CRT). DNA samples were obtained from peripheral blood leukocytes for GR genotyping.

RESULTS

In patients with active CS, normalized handgrip strength of the dominant and nondominant hand was higher in A3669G minor allele than in wildtype carriers (P = .006 and P = .021, respectively). CS patients in remission and ruled-out CS showed no differences in handgrip strength regarding A3669G minor allele and wildtype carriers. Male CS patients harboring the ER22/23EK wildtype presented lower hand grip strength than minor allele carriers (P = .049 dominant hand; P = .027 nondominant hand). The other polymorphisms did not influence handgrip strength. CRT showed no differences regarding GR polymorphisms carrier status.

CONCLUSION

Handgrip strength seems to be more susceptible to hypercortisolism in A3669G wildtype than in A3669G minor allele carriers. This might partially explain the inter-individual differences of glucocorticoid-induced myopathy in patients with endogenous CS. ER22/23EK polymorphism seems to exert sex-specific differences.

Role of NR3C1 and GAS5 genes polymorphisms in multiple sclerosis

Introduction: Multiple sclerosis (MS) as a progressive chronic disease of the central nervous system (CNS) is characterized by demyelination and axonal loss. Results of genetic studies and clinical trials have proved a key role for the immune system in the pathogenesis of MS. Glucocorticoids (GR) are regarded as potent therapeutic compounds for autoimmune and inflammatory diseases which act through their receptors encoded by Nuclear Receptor Subfamily 3 Group C Member 1 (NR3C1) gene. Meanwhile, the long non-coding RNA (lncRNA) growth arrest specific 5 (GAS5) interacts with GR through binding to the DNA-binding domain (DBD) region and reduces GR transcriptional activity.Methods: The purpose of our study was to evaluate the association between MS and polymorphisms within NR3C1 (rs6189/6190, rs56149945, rs41423247) and GAS5 (rs55829688) genes in 300 relapsing-remitting MS patients and 300 healthy subjects.Results: We demonstrated significant differences in distribution of genotype, allele and haplotype frequencies of rs6189, rs41423247 and rs55829688 between the study groups.Conclusion: Our data may suggest that rs6189, rs41423247 and rs55829688 are associated with the increased risk of MS development. Future studies are needed to verify our results in larger sample sizes and elaborate the underlying mechanisms for contribution of these variants in MS disease.

The Glucocorticoid Receptor in Cardiovascular Health and Disease

The glucocorticoid receptor is a member of the nuclear receptor family that controls many distinct gene networks, governing various aspects of development, metabolism, inflammation, and the stress response, as well as other key biological processes in the cardiovascular system. Recently, research in both animal models and humans has begun to unravel the profound complexity of glucocorticoid signaling and convincingly demonstrates that the glucocorticoid receptor has direct effects on the heart and vessels in vivo and in vitro. This research has contributed directly to improving therapeutic strategies in human disease. The glucocorticoid receptor is activated either by the endogenous steroid hormone cortisol or by exogenous glucocorticoids and acts within the cardiovascular system via both genomic and non-genomic pathways. Polymorphisms of the glucocorticoid receptor are also reported to influence the progress and prognosis of cardiovascular disease. In this review, we provide an update on glucocorticoid signaling and highlight the critical role of this signaling in both physiological and pathological conditions of the cardiovascular system. With increasing in-depth understanding of glucocorticoid signaling, the future is promising for the development of targeted glucocorticoid treatments and improved clinical outcomes.

Uncovering a multitude of human glucocorticoid receptor variants: an expansive survey of a single gene

Background

Glucocorticoids are commonly used in the clinical setting for their potent anti-inflammatory effects; however, significant variations in response to treatment have been demonstrated. Although the underlying mechanisms have yet to be fully understood, this variable response may be a result of alterations in human glucocorticoid receptor (hGR) expression and function. In addition to hGRα, the biologically active isoform, a screening of current databases and publications revealed five alternative splice isoforms and hundreds of variants that have been reported to date. Many of these changes in the hGR-coding gene, NR3C1, have been linked to pathophysiology. However, many studies focus on evaluating hGR expression in vitro or detecting previously reported variants.

Results

In this study, blood from healthy volunteers, burn and asthma patients, as well as from peripheral blood mononuclear cells isolated from leukoreduced donor whole blood, were screened for NR3C1 isoforms. We identified more than 1500 variants, including an additional 21 unique splice isoforms which contain 15 new cryptic exons. A dynamic database, named the Universal hGR (UhGR), was created to annotate and visualize the variants.

Conclusion

This identification of naturally occurring and stress-induced hGR isoforms, as well as the establishment of an hGR-specific database, may reveal new patterns or suggest areas of interest that will lead to the improved understanding of the human stress response system.

Electronic supplementary material

The online version of this article (10.1186/s12863-019-0718-z) contains supplementary material, which is available to authorized users.

Glucocorticoid Resistance

Primary generalized glucocorticoid resistance or Chrousos syndrome is a rare disorder, which affects all tissues expressing the human glucocorticoid receptor. It is characterized by generalized, partial tissue insensitivity to glucocorticoids caused by genetic defects in the NR3C1 gene. We and others have applied standard methods of molecular and structural biology to investigate the molecular mechanisms and conformational alterations through which the mutant glucocorticoid receptors lead to the broad spectrum of clinical manifestations of Chrousos syndrome. The ever-increasing application of novel technologies, including the next-generation sequencing, will enhance our knowledge in factors that influence the glucocorticoid signal transduction in a positive or negative fashion.

Healthy glucocorticoid receptor N363S carriers dysregulate gene expression associated with metabolic syndrome

The glucocorticoid receptor single-nucleotide polymorphism (SNP) N363S has been reported to be associated with metabolic syndrome, type 2 diabetes, and cardiovascular disease. Our aim was to determine how the N363S SNP modifies glucocorticoid receptor signaling in a healthy population of individuals prior to the onset of disease. We examined the function of the N363S SNP in a cohort of subjects from the general population of North Carolina. Eighteen N363S heterozygous carriers and 36 noncarrier, control subjects were examined for clinical and biochemical parameters followed by a low-dose dexamethasone suppression test to evaluate glucocorticoid responsiveness. Serum insulin measurements revealed that N363S carriers have higher levels of insulin, although not statistically significant, compared with controls. Glucocorticoid receptor protein levels evaluated in peripheral blood mononuclear cells from each clinical subject showed no difference between N363S and control. However, investigation of gene expression profiles in macrophages isolated from controls and N363S carriers using microarray, quantitative RT-PCR, and NanoString analyses revealed that the N363S SNP had an altered profile compared with control. These changes in gene expression occurred in both the absence and the presence of glucocorticoids. Thus, our observed difference in gene regulation between normal N363S SNP carriers and noncarrier controls may underlie the emergence of metabolic syndrome, type 2 diabetes, and cardiovascular disease associated with the N363S polymorphism.

Some GCR Polymorphisms (N363S, ER22/23EK, and Bcl-1) May Influence Steroid-induced Toxicities and Survival Rates in Children With ALL

We investigated whether an altered individual glucocorticoid sensitivity due to particular glucocorticoid receptor single-nucleotide polymorphisms (SNPs) (N363S, ER22/23EK, and Bcl-1) influences the susceptibility to steroid-related toxicities, prognostic factors, and survival rates in children with acute lymphoblastic leukemia. In total, 346 pediatric patients with acute lymphoblastic leukemia were enrolled in our study. Their carrier status was investigated by allele-specific polymerase chain reaction analysis. Clinical and laboratory signs of glucocorticoid-related toxicities, day-8 prednisone response, 5-year event-free survival, and 5-year overall survival rates were analyzed and compared retrospectively. Hepatotoxicity occurred significantly more often in 363S carriers (P=0.004), and glucose metabolism abnormalities were more common in 363S carriers (P=0.001), but did not occur in patients with the ER22/23EK SNP. Hypertension and central nervous system/behavioral changes did not occur in patients with the ER22/23EK SNP. None of the patients with the N363S SNP, the ER22/23EK polymorphism, or the GG genotype for the Bcl-1 polymorphism had a poor prednisone response. The 363S carriers had significantly better 5-year event-free survival (P=0.012) and 5-year overall survival (P=0.013) rates compared with noncarriers. The Bcl-1 SNP was not associated with any of the toxicities investigated or survival. Children with the N363S polymorphism in the glucocorticoid receptor gene were more prone to steroid-related toxicities, whereas those with the ER22/23EK polymorphism were less susceptible. Children with the N363S polymorphism may have more favorable survival rates.

Is there a bi-directional relationship between depression and obesity among adult men and women? Systematic review and bias-adjusted meta analysis

The rapidly increasing prevalence of both obesity and depression represent two major public health concerns worldwide. But the evidence regarding the direction and strength of the association between these two disorders, for both adult men and women, are remain inconclusive. We systematically reviewed publications from five different databases: Pubmed, Embase, BIOSIS, CINAHL and PsychINFO. A total of 21 articles were included for the systematic review and 19 of them for the meta-analysis using a bias-adjusted (quality effect) model. This resulted in the inclusion of approximately 226,063 (33.7% men) participants. Those who were depressed had a 37% (RR: 1.37, 95% CI: 1.17, 1.48) increased risk of being obese, and who were obese had an 18% increased risk of being depressed (RR: 1.18, 95% CI: 1.04, 1.35). Those who were depressed had a 2% (RD: 0.02, 95% CI: 0.01, 0.03) excess risk of obesity, however, the reciprocal associations were not significant. The association between overweight and depression was not found significant in either direction. Both men and women were at risk of obesity and depression bi-directionally. In sensitivity analyses bi-directional associations were more pronounced among young and middle aged adults and in studies with longer follow-up. The findings of this study suggest that the strength of the association is greater for the direction leading from depression to obesity and this link was more pronounced for young and middle aged women.

Impact of glucocorticoid receptor gene (NR3C1) polymorphisms in Turkish patients with metabolic syndrome

BACKGROUND

The metabolic syndrome (MetS) is characterized by a cluster of metabolic factors, including insulin resistance and type-2 diabetes, abdominal obesity, dyslipidemia, hypertension and microalbuminuria. Impaired glucocorticoid receptor (GR) activity also plays an important role in the etiology of MetS. The objective of our study is to evaluate the effects of GR gene polymorphisms (BclI, N363S, TthIII1 and ER22/23EK) in Turkish patients with MetS.

MATERIALS AND METHODS

Seventy subjects with MetS and 185 healthy controls were enrolled in the study. PCR-RFLP analysis was used for genotyping. Results for each polymorphism have been verified by allele-specific oligonucleotide analysis.

RESULTS

BclI GG genotype was significantly associated with an increased risk of MetS (p = 0.02). Also, only in women, the G allele carriers were significantly associated with higher C-peptide. T allele carriers of TthIII1 polymorphism were significantly associated with higher C-peptide, triglyceride, insulin and C-reactive protein (CRP, p value 0.048, 0.022, 0.005 and 0.022, respectively), and lower fasting blood glucose (FBG, p = 0.02). The combined carriers of BclI polymorphism G allele and TthIII1 polymorphism T allele were significantly associated with higher diastolic blood pressure in all patients, and lower FBG and postprandial blood glucose in only men. All the ER22/23EK polymorphisms coexisted with polymorphic variant of TthIII1 (p = 0.0058).

CONCLUSION

The presence of homozygote polymorphic variant of BclI might be good predictive markers for the disease susceptibility. The BclI and the TthIII1 polymorphism are associated with sex-specific clinical parameters. Our findings also suggest that the combination of BclI and TthIII1 polymorphisms may play a protective role in blood glucose.

Is increased antidepressant exposure a contributory factor to the obesity pandemic?

Major depressive disorder (MDD) and obesity are both common heterogeneous disorders with complex aetiology, with a major impact on public health. Antidepressant prescribing has risen nearly 400% since 1988, according to data from the Centers for Disease Control and Prevention (CDC). In parallel, adult obesity rates have doubled since 1980, from 15 to 30 percent, while childhood obesity rates have more than tripled. Rising obesity rates have significant health consequences, contributing to increased rates of more than thirty serious diseases. Despite the concomitant rise of antidepressant use and of the obesity rates in Western societies, the association between the two, as well as the mechanisms underlying antidepressant-induced weight gain, remain under explored. In this review, we highlight the complex relationship between antidepressant use, MDD and weight gain. Clinical findings have suggested that obesity may increase the risk of developing MDD, and vice versa. Hypothalamic-pituitary-adrenal (HPA) axis activation occurs in the state of stress; concurrently, the HPA axis is also dysregulated in obesity and metabolic syndrome, making it the most well-understood shared common pathophysiological pathway with MDD. Numerous studies have investigated the effects of different classes of antidepressants on body weight. Previous clinical studies suggest that the tricyclics amitriptyline, nortriptyline and imipramine, and the serotonin norepinephrine reuptake inhibitor mirtazapine are associated with weight gain. Despite the fact that selective serotonin reuptake inhibitor (SSRI) use has been associated with weight loss during acute treatment, a number of studies have shown that SSRIs may be associated with long-term risk of weight gain; however, because of high variability and multiple confounds in clinical studies, the long-term effect of SSRI treatment and SSRI exposure on body weight remains unclear. A recently developed animal paradigm shows that the combination of stress and antidepressants followed by long-term high-fat diet results, long after discontinuation of antidepressant treatment, in markedly increased weight, in excess of what is caused by high-fat diet alone. On the basis of existing epidemiological, clinical and preclinical data, we have generated the testable hypothesis that escalating use of antidepressants, resulting in high rates of antidepressant exposure, might be a contributory factor to the obesity epidemic.

Glucocorticoid Receptor (NR3C1) Variants Associate with the Muscle Strength and Size Response to Resistance Training

Glucocorticoid receptor (NR3C1) polymorphisms associate with obesity, muscle strength, and cortisol sensitivity. We examined associations among four NR3C1 polymorphisms and the muscle response to resistance training (RT). European-American adults (n = 602, 23.8±0.4yr) completed a 12 week unilateral arm RT program. Maximum voluntary contraction (MVC) assessed isometric strength (kg) and MRI assessed biceps size (cm2) pre- and post-resistance training. Subjects were genotyped for NR3C1 -2722G>A, -1887G>A, -1017T>C, and +363A>G. Men carrying the -2722G allele gained less relative MVC (17.3±1.2vs33.5±6.1%) (p = 0.010) than AA homozygotes; men with -1887GG gained greater relative MVC than A allele carriers (19.6±1.4vs13.2±2.3%) (p = 0.016). Women carrying the -1017T allele gained greater relative size (18.7±0.5vs16.1±0.9%) (p = 0.016) than CC homozygotes. We found sex-specific NR3C1 associations with the muscle strength and size response to RT. Future studies should investigate whether these associations are partially explained by cortisol's actions in muscle tissue as they interact with sex differences in cortisol production.

Polymorphisms in NR3C1 gene associated with risk of metabolic syndrome in a Chinese population

Polymorphisms of the NR3C1 (glucocorticoid receptor) gene have been reported to be associated with altered glucocorticoids sensitivity and changes in body composition and metabolic parameters. This study explored the relationship between single nucleotide polymorphisms (SNPs) of the NR3C1 gene and metabolic syndrome (MetS) in a Chinese population. Fourteen tag-SNPs and five functionally important SNPs in the NR3C1 gene were genotyped in MetS patients (n = 431) and normal controls (n = 461) using the high-throughput Sequenom genotyping platform. Genotype, allelic and haplotype associations were examined using logistic regression and Haploview. There are four SNPs significantly associated with MetS. The T allele of rs2963156 was associated with an increased risk effect for MetS (adjusted OR = 1.66, 95 % CI 1.25-2.22, P = 0.001). By contrast, rs10052957 A allele carriers were significantly associated with a decreased risk of MetS (adjusted OR = 0.58, 95 % CI 0.42-0.80, P = 0.001). Rs41423247 GG genotype (adjusted OR = 2.01, 95 % CI 1.25-3.22, P = 0.004), and rs7701443 AA genotype (adjusted OR = 1.88, 95 % CI 1.24-2.83, P = 0.003) were significantly associated with an increased risk of MetS. Haplotype CGGA is risk conferring (adjusted OR = 1.53, 95 % CI 1.06-2.20, P = 0.023), whereas haplotype CCAG was protective (adjusted OR = 0.30, 95 % CI 0.20-0.47, P < 0.001). Polymorphism of NR3C1 gene is associated with MetS and may contribute to the susceptibility of MetS.

Comprehensive overview of the structure and regulation of the glucocorticoid receptor

Glucocorticoids are among the most prescribed drugs worldwide for the treatment of numerous immune and inflammatory disorders. They exert their actions by binding to the glucocorticoid receptor (GR), a member of the nuclear receptor superfamily. There are several GR isoforms resulting from alternative RNA splicing and translation initiation of the GR transcript. Additionally, these isoforms are all subject to several transcriptional, post-transcriptional, and post-translational modifications, all of which affect the protein's stability and/or function. In this review, we summarize recent knowledge on the distinct GR isoforms and the processes that generate them. We also review the importance of all known transcriptional, post-transcriptional, and post-translational modifications, including the regulation of GR by microRNAs. Moreover, we discuss the crucial role of the putative GR-bound DNA sequence as an allosteric ligand influencing GR structure and activity. Finally, we describe how the differential composition and distinct regulation at multiple levels of different GR species could account for the wide and diverse effects of glucocorticoids.

Associations between polymorphisms in the glucocorticoid-receptor gene and cardiovascular risk factors in a Chinese population

Background

Glucocorticoid is an important regulator of energy homeostasis. Glucocorticoid receptor (GR) gene polymorphisms that contribute to variability in glucocorticoid sensitivity have been identified. We explored the associations of single-nucleotide polymorphisms (SNPs) of the GR gene with traditional cardiovascular risk factors in the Chinese Han population.

Methods

We recruited 762 consecutive adults who underwent a regular physical examination at Beijing Xuanwu Hospital. Blood pressure, glucose, lipid levels (total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein [LDL] cholesterol and triglycerides), body mass index (BMI), and waist-to-hip ratio were measured. Fourteen tag SNPs and 5 functional SNPs were selected and genotyped using the high-throughput Sequenom genotyping platform. Differences between genotypes/alleles for each SNP were adjusted for sex and age and tested using a general linear model procedure. Various models of inheritance, including additive, dominant, and recessive, were tested.

Results

Among the 19 SNPs examined, 5 markers were associated with cardiovascular risk factors. The rs41423247 GG genotype and the rs7701443 AA genotype were associated with higher BMI and systolic blood pressure (P < 0.0004), and the rs17209251 GG genotype was associated with higher systolic blood pressure (P < 0.0004). Lower systolic blood pressure, total cholesterol, and LDL cholesterol were observed among rs10052957 A allele carriers (P < 0.0004), and lower plasma glucose and LDL-cholesterol concentrations were observed among rs2963156 TT carriers (P < 0.0004).

Conclusions

Polymorphism of the GR gene was associated with cardiovascular risk factors and may contribute to susceptibility to cardiovascular disease.

Obesity and asthma: a coincidence or a causal relationship? A systematic review

BACKGROUND AND AIM

Epidemiological data has established increasing adiposity as a risk factor for incident asthma. However, the mechanisms underlying the association between obesity and asthma are incompletely understood. In the present paper, we review current knowledge of possible mechanisms mediating the observed association between obesity and asthma.

METHODS

Systematic literature review.

RESULTS

Obesity and asthma share some etiological factors, such as a common genetic predisposition and effects of in utero conditions, and may also have common predisposing factors such as physical activity and diet. Obesity results in important changes in the mechanical properties of the respiratory system which could explain the occurrence of asthma. However, there are also plausible biological mechanisms whereby obesity could be expected to either cause or worsen asthma. These include co-morbidities such as gastro-oesophageal reflux, complications from sleep-disordered breathing, breathing at low lung volumes, chronic systemic inflammation, and endocrine factors, including adipokines and reproductive hormones. Obesity related asthma is in general not associated with eosinophilic airway inflammation, and adipokines are likely to play important roles in the inflammatory pathogenesis of asthma in obese individuals.

CONCLUSION

The association between obesity and asthma is not straightforward, and further knowledge is clearly needed, as understanding the underlying mechanisms may lead to new therapeutic options for this high-risk part of the asthma population.

Lack of association between NR3C1 polymorphism and glucocorticoid resistance in Chinese patients with immune thrombocytopenia

Resistance to glucocorticoids (GCs) is a tricky problem in therapy for immune thrombocytopenia (ITP). As GCs exert their effects through glucocorticoid receptor (GR), being a GR gene, NR3C1 is thought to connect with individual differences in GC responsiveness during GCs treatments. We analyzed the frequency of three novel single nucleotide polymorphisms (SNPs) of NR3C1 in ITP patients and evaluated the role of these genetic variants in GCs therapy. Four hundred and seventy-three patients with ITP and 160 healthy controls were recruited. Patients were allocated into GCs-responsive (n = 358) and -non-responsive group (n = 115). All subjects of the three groups were genotyped by the PCR-RFLP (restriction fragment length polymorphism) method for the BclI, N363S and ER22/23EK polymorphisms. Assess the statistical differences of genotypes between ITP and controls, and those between GCs- responsive and non-responsive groups. In healthy controls, BclI-GG/GC/CC occurred with 0.581/0.35/0.069 frequency. In ITP patients, BclI-GG/GC/CC was found with 0.617/0.353/0.03 frequency. There was no statistically differences between ITP and controls (p = 0.070). In GCs-responsive and -non-responsive group, BclI-GG, GC, CC occurred with frequencies of 0.628/0.352/0.02 and 0.583/0.357/0.061, respectively. No correlations in the variants of BclI was found between the GCs-responsive and -non-responsive group (p = 0.086). Neither N363S nor ER22/23EK polymorphism was observed in all 636 participants. The BclI polymorphism is not related to the response of GCs in patients with ITP. Furthermore, we did not observe N363S and ER22/23EK polymorphism in Chinese Han population.

Primary generalized familial and sporadic glucocorticoid resistance (Chrousos syndrome) and hypersensitivity

Familial or sporadic primary generalized glucocorticoid resistance or Chrousos syndrome is a rare genetic condition characterized by generalized, partial, target-tissue insensitivity to glucocorticoids and a consequent hyperactivation of the hypothalamic-pituitary-adrenal (HPA) axis. Primary generalized glucocorticoid hypersensitivity (PGGH) represents the mirror image of the former, and is characterized by generalized, partial, target-tissue hypersensitivity to glucocorticoids, and compensatory hypoactivation of the HPA axis. The molecular basis of both conditions has been ascribed to mutations in the human glucocorticoid receptor (hGR) gene, which impair the molecular mechanisms of hGR action and alter tissue sensitivity to glucocorticoids. This review summarizes the pathophysiology, molecular mechanisms and clinical aspects of Chrousos syndrome and PGGH.

Visceral adipose tissue: emerging role of gluco- and mineralocorticoid hormones in the setting of cardiometabolic alterations

Several clinical and experimental lines of evidence have highlighted the detrimental effects of visceral adipose tissue excess on cardiometabolic parameters. Besides, recent findings have shown the effects of gluco-and mineralocorticoid hormones on adipose tissue and have also underscored the interplay existing between such adrenal steroids and their respective receptors in the modulation of adipose tissue biology. While the fundamental role played by glucocorticoids on adipocyte differentiation and storage was already well known, the relevance of the mineralocorticoids in the physiology of the adipose organ is of recent acquisition. The local and systemic renin–angiotensin–aldosterone system (RAAS) acting on adipose tissue seems to contribute to the development of the cardiometabolic phenotype so that its modulation can have deep impact on human health. A better understanding of the pathophysiology of the adipose organ is of crucial importance in order to identify possible therapeutic approaches that can avoid the development of such cardiovascular and metabolic sequelae.

Clinical and biochemical impact of BCL1 polymorphic genotype of the glucocorticoid receptor gene in patients with adrenal incidentalomas

BACKGROUND

Adrenal incidentaloma (AI) is a common clinical problem. Subtle hormonal abnormalities are present in a substantial proportion of patients. BCL1 gene polymorphism of the glucocorticoid receptor (GR) is associated with increased sensitivity to glucocorticoid action. The genotype- phenotype associations of this polymomorphism in patients presenting with AI has not been extensively investigated.

AIM

A cross-sectional study in secondary/tertiary care centers.

SUBJECTS/METHODS

Ninety-five subjects with AI were genotyped for the BCL1 GR gene polymorphism. Patients underwent an oral glucose tolerance test and a dexamethasone suppression test (DST). The presence of subclinical hypercortisolism, features of metabolic syndrome, and osteoporosis/ osteopenia were also assessed.

RESULTS

No significant differences in markers of adrenal function between BCL1 carriers and non-carriers were revealed. Also, no difference was found in the features of metabolic syndrome, as well as in bone metabolism and density between these 2 groups. However, DST suppressor patients belonged more frequently to the BCL1 carriers group (41 out of 69 patients, 59.4% vs 9 out of 26 patients, 34.6%, p=0.0039), had smaller total adenoma size (2.4±0.2 cm vs 3.5±0.4 cm, p=0.04), and lower incidence of bilateral adrenal masses (18.8% vs 46.2%, p=0.01).

CONCLUSIONS

AI patients who also carry the polymorphic BCL1 variant exhibit smaller size adrenal nodules. Those AI patients with complete DST suppression had a higher incidence of the polymorphic BCL1 variant. However, this study failed to demonstrate any significant impact of BCL1 GR polymorphism on the frequency of cortisol-dependent co-morbidities in patients with AI.

Variation in DNA repair gene XRCC3 affects susceptibility to astrocytomas and glioblastomas

The gene XRCC3 (X-ray cross complementing group 3) has the task of repairing damage that occurs when there is recombination between homologous chromosomes. Repair of recombination between homologous chromosomes plays an important role in maintaining genome integrity, although it is known that double-strand breaks are the main inducers of chromosomal aberrations. Changes in the XRCC3 protein lead to an increase in errors in chromosome segregation due to defects in centrosomes, resulting in aneuploidy and other chromosomal aberrations, such as small increases in telomeres. We examined XRCC3 Thr241Met polymorphism using PCR-RFLP in 80 astrocytoma and glioblastoma samples. The individuals of the control group (N = 100) were selected from the general population of the São Paulo State. Odds ratio and 95%CI were calculated using a logistic regression model. Patients who had the allele Met of the XRCC3 Thr241Met polymorphism had a significantly increased risk of tumor development (odds ratio = 3.13; 95% confidence interval = 1.50-6.50). There were no significant differences in overall survival of patients. We suggest that XRCC3 Thr241Met polymorphism is involved in susceptibility for developing astrocytomas and glioblastomas.

Analysis of the polymorphisms XRCC1Arg194Trp and XRCC1Arg399Gln in gliomas

XRCC genes (X-ray cross-complementing group) were discovered mainly for their roles in protecting mammalian cells against damage caused by ionizing radiation. Studies determined that these genes are important in the genetic stability of DNA. Although the loss of some of these genes does not necessarily confer high levels of sensitivity to radiation, they have been found to represent important components of various pathways of DNA repair. To ensure the integrity of the genome, a complex system of DNA repair was developed. Base excision repair is the first defense mechanism of cells against DNA damage and a major event in preventing mutagenesis. Repair genes may play an important role in maintaining genomic stability through different pathways that are mediated by base excision. In the present study, we examined XRCC1Arg194Trp and XRCC1Arg399Gln polymorphism using PCR-RFLP in 80 astrocytoma and glioblastoma samples. Patients who had the allele Trp of the XRCC1Arg194Trp polymorphism had an increased risk of tumor development (OR = 8.80; confidence interval at 95% (95%CI) = 4.37-17.70; P < 0.001), as did the allele Gln of XRCC1Arg399Gln (OR = 1.01; 95%CI = 0.53-1.93; P = 0.971). Comparison of overall survival of patients did not show significant differences. We suggest that XRCC1Arg194Trp and XRCC1Arg399Gln polymorphisms are involved in susceptibility for developing astrocytomas and glioblastomas.

Stress and breast cancer: from epidemiology to molecular biology

Stress exposure has been proposed to contribute to the etiology of breast cancer. However, the validity of this assertion and the possible mechanisms involved are not well established. Epidemiologic studies differ in their assessment of the relative contribution of stress to breast cancer risk, while physiological studies propose a clear connection but lack the knowledge of intracellular pathways involved. The present review aims to consolidate the findings from different fields of research (including epidemiology, physiology, and molecular biology) in order to present a comprehensive picture of what we know to date about the role of stress in breast cancer development.

The genetics of obesity and the metabolic syndrome

In this review, we discuss the genetic architecture of obesity and the metabolic syndrome, highlighting recent advances in identifying genetic variants and loci responsible for a portion of the variation in components of the metabolic syndrome, namely, adiposity traits, serum HDL and triglycerides, blood pressure, and glycemic traits. We focus particularly on recent progress from large-scale genome-wide association studies (GWAS), by detailing their successes and how lessons learned can pave the way for future discovery. Results from recent GWAS coalesce with earlier work suggesting numerous interconnections between obesity and the metabolic syndrome, developed through several potentially pleiotropic effects. We detail recent work by way of a case study on the cadherin 13 gene and its relation with adiponectin in the HyperGEN and the Framingham Heart Studies, and its association with obesity and the metabolic syndrome. We provide also a gene network analysis of recent variants related to obesity and metabolic syndrome discovered through genome-wide association studies, and 4 gene networks based on searching the NCBI database.

Depression and obesity: do shared genes explain the relationship?

BACKGROUND

Studies have found a modest association between depression and obesity, especially in women. Given the substantial genetic contribution to both depression and obesity, we sought to determine whether shared genetic influences are responsible for the association between these two conditions.

METHODS

Data were obtained from 712 monozygotic and 281 dizygotic female twin pairs who are members of the community-based University of Washington Twin Registry. The presence of depression was determined by self-report of doctor-diagnosed depression. Obesity was defined as body mass index of > or =30 kg/m(2), based on self-reported height and weight. Generalized estimating regression models were used to assess the age-adjusted association between depression and obesity. Univariate and bivariate structural equation models estimated the components of variance attributable to genetic and environmental influences.

RESULTS

We found a modest phenotypic association between depression and obesity (odds ratio=1.6, 95% confidence interval=1.2-2.1). Additive genetic effects contributed substantially to depression (57%) and obesity (81%). The best-fitting bivariate model indicated that 12% of the genetic component of depression is shared with obesity.

CONCLUSIONS

The association between depression and obesity in women may be in part due to shared genetic risk for both conditions. Future studies should examine the genetic, environmental, social, and cultural mechanisms underlying the relationship between this association.

The human glucocorticoid receptor: molecular basis of biologic function

The characterization of the subfamily of steroid hormone receptors has enhanced our understanding of how a set of hormonally derived lipophilic ligands controls cellular and molecular functions to influence development and help achieve homeostasis. The glucocorticoid receptor (GR), the first member of this subfamily, is a ubiquitously expressed intracellular protein, which functions as a ligand-dependent transcription factor that regulates the expression of glucocorticoid-responsive genes. The effector domains of the GR mediate transcriptional activation by recruiting coregulatory multi-subunit complexes that remodel chromatin, target initiation sites, and stabilize the RNA-polymerase II machinery for repeated rounds of transcription of target genes. This review summarizes the basic aspects of the structure and actions of the human (h) GR, and the molecular basis of its biologic functions.

Clinical features associated with glucocorticoid receptor polymorphisms. An overview

The glucocorticoid receptor (GR) is crucial for the effects of glucocorticoids (GCs). Several polymorphisms of the GR are associated with altered sensitivity to GCs. For the ER22/23EK polymorphism, a relative GC resistance has been demonstrated. In vivo, this was suggested by a smaller response to a dexamethasone suppression test (DST), whereas in vitro experiments showed a diminished transactivational activity. The associated features of ER22/23EK carriers consist of favorable metabolic and body compositional conditions. In elderly subjects this polymorphism was associated with longevity and decreased risk of dementia. Interestingly, recent studies also showed an increased risk of major depression. In contrast, the N363S polymorphism was reported to be associated with an enhanced sensitivity to GCs, as was demonstrated by a DST. This polymorphism has also been associated with increased body mass index (BMI) and LDL-cholesterol levels, as well as increased risk of cardiovascular disease. However, additional studies yielded conflicting results, showing no associations with being overweight. The BclI polymorphism is also associated with increased GC sensitivity. In addition, associations with increased abdominal fat mass, Crohn's disease and, remarkably, major depression have been reported. Another GR polymorphism, located in exon 9beta, is associated with increased expression and stabilization of the dominant negative splice variant GR-beta. Carriers of this polymorphism displayed a relative GC resistance in vitro as evidenced by diminished transrepressional activity, which is important for the immune system and inflammation. Associations have been found with increased inflammatory parameters, cardiovascular disease, and rheumatoid arthritis. In this article, studies concerning these clinically relevant GR variants are discussed.

Glucocorticoid Receptor in Health and Disease

Glucocorticoid hormones are essential for life, have a vital place in the treatment of inflammatory and autoimmune diseases and are increasingly implicated in the pathogenesis of a number of common disorders. Their action is mediated by an intracellular receptor protein, the glucocorticoid receptor (GR), functioning as a ligand-inducible transcription factor. Multiple synthetic glucocorticoids are used as potent antiinflammatory and immunosuppressive agents, but their therapeutic usefulness is limited by a wide range and severity of side-effects. One of the most important pharmaceutical goals has been to design steroidal and non-steroidal GR ligands with profound therapeutic efficacy and reduced unwanted effects. The therapeutic benefit of glucocorticoid agonists is frequently compromised by resistance to glucocorticoids, which may depend on: access of the hormones to target cells, steroid metabolism, expression level and isoform composition of the GR protein, mutations and polymorphisms in the GR gene and association of the receptor with chaperone proteins. The major breakthrough into the critical role of glucocorticoid signaling in the maintenance of homeostasis and pathogenesis of diseases, as well as into the molecular mechanisms underlying the therapeutic usefulness of antiinflammatory drugs acting through the GR is expected to result from the current progress in large-scale gene expression profiling technologies and computational biology.

Role of shared genetic and environmental factors in symptoms of depression and body composition

BACKGROUND

Both obesity and lean mass have been correlated with symptoms of depression.

OBJECTIVE

To investigate the contribution of genetic and environmental factors in the co-occurrence of obesity and lean mass with symptoms of depression.

METHODS

Individuals were 2383 participants of the Erasmus Rucphen Family study. Symptoms of depression were assessed using the Center for Epidemiologic Studies Depression Scale and the Hospital Anxiety and Depression Scale. Anthropometric and dual-energy X-ray absorptiometry total body scans were obtained for the assessment of body composition. The role of shared genetic and shared environmental factors was quantified by estimating genetic and environmental correlations between symptoms of depression and measures of body composition.

RESULTS

Phenotypic correlations between body composition and symptoms of depression ranged from -0.08 to 0.08. Heritability estimates for body composition ranged from 0.40 to 0.46 (P<0.001) in women and from 0.35 to 0.51 (P<0.001) in men, and heritability estimates for depression scores were higher in women (0.34 and 0.37) than in men (0.13 and 0.21). No consistent genetic correlations between measures of body composition and symptoms of depression were found. We did find a significant consistent environmental correlation between depression scores and lean mass index (environmental correlation=-0.23 for Center for Epidemiologic Studies Depression Scale and -0.31 for Hospital Anxiety and Depression Scale).

CONCLUSION

In our study, there is no evidence that the co-occurrence of symptoms of depression and body composition result from a common genetic pathway.

Build-ups in the supply chain of the brain: on the neuroenergetic cause of obesity and type 2 diabetes mellitus

Obesity and type 2 diabetes have become the major health problems in many industrialized countries. A few theoretical frameworks have been set up to derive the possible determinative cause of obesity. One concept views that food availability determines food intake, i.e. that obesity is the result of an external energy "push" into the body. Another one views that the energy milieu within the human organism determines food intake, i.e. that obesity is due to an excessive "pull" from inside the organism. Here we present the unconventional concept that a healthy organism is maintained by a "competent brain-pull" which serves systemic homeostasis, and that the underlying cause of obesity is "incompetent brain-pull", i.e. that the brain is unable to properly demand glucose from the body. We describe the energy fluxes from the environment, through the body, towards the brain with a mathematical "supply chain" model and test whether its predictions fit medical and experimental data sets from our and other research groups. In this way, we show data-based support of our hypothesis, which states that under conditions of food abundance incompetent brain-pull will lead to build-ups in the supply chain culminating in obesity and type 2 diabetes. In the same way, we demonstrate support of the related hypothesis, which states that under conditions of food deprivation a competent brain-pull mechanism is indispensable for the continuance of the brain s high energy level. In conclusion, we took the viewpoint of integrative physiology and provided evidence for the necessity of brain-pull mechanisms for the benefit of health. Along these lines, our work supports recent molecular findings from the field of neuroenergetics and continues the work on the "Selfish Brain" theory dealing with the maintenance of the cerebral and peripheral energy homeostasis.

Molecular mechanisms regulating glucocorticoid sensitivity and resistance

Glucocorticoid receptor agonists are mainstays in the treatment of various malignancies of hematological origin. Glucocorticoids are included in therapeutic regimens for their ability to stimulate intracellular signal transduction cascades that culminate in alterations in the rate of transcription of genes involved in cell cycle progression and programmed cell death. Unfortunately, subpopulations of patients undergoing systemic glucocorticoid therapy for these diseases are or become insensitive to glucocorticoid-induced cell death, a phenomenon recognized as glucocorticoid resistance. Multiple factors contributing to glucocorticoid resistance have been identified. Here we summarize several of these mechanisms and describe the processes involved in generating a host of glucocorticoid receptor isoforms from one gene. The potential role of glucocorticoid receptor isoforms in determining cellular responsiveness to glucocorticoids is emphasized.

Glucocorticoid receptor gene variant in the 3' untranslated region is associated with multiple measures of blood pressure

CONTEXT

The glucocorticoid receptor (GR) is a key hormone in the hypothalamus-pituitary-adrenal axis that regulates many pathways including blood pressure homeostasis. Thus, GR gene variation may influence interindividual differences in blood pressure in human populations.

OBJECTIVE

We resequenced individual GR alleles for comprehensive discovery of GR variants and their chromosomal phase in three major American ethnic groups. We examined the influence of GR variants on blood pressure in large numbers of families using family-based association methods.

DESIGN AND PARTICIPANTS

For association studies, we genotyped GR variants in family members from the Genetic Epidemiology Network of Arteriopathy (GENOA) study that were measured for multiple blood pressure traits. The GENOA families consisted of African-Americans, Mexican-Americans, and European-Americans.

MAIN MEASUREMENTS

The blood pressure measurements for association studies included systolic blood pressure, diastolic blood pressure, mean arterial pressure, and pulse pressure.

RESULTS

Single-nucleotide polymorphisms (SNPs) identified by resequencing were tested for associations with blood pressure measures in GENOA families. Analysis of individual SNPs identified significant associations of rs6198 A/G in exon 9beta with multiple blood pressure measures in European-Americans. Analysis of GR haplotypes found significant associations of a haplotype that is distinguished by rs6198 A/G.

CONCLUSIONS

Significant associations of blood pressure with rs6198 A/G likely reflect allelic effects on GR signaling. This SNP disrupts a 3' untranslated region sequence element in exon 9beta that destabilizes mRNA, resulting in increased production of the inactive GRbeta isoform. Excess heterodimerization with the active GRalpha isoform may reduce GR signaling with subsequent physiological effects on blood pressure regulation.

The role of glucocorticoids and progestins in inflammatory, autoimmune, and infectious disease

A bidirectional communication exists between the CNS and the immune system. The autonomic nervous system, through neurotransmitters and neuropeptides, works in parallel with the hypothalamic-pituitary-adrenal axis through the actions of glucocorticoids to modulate inflammatory events. The immune system, through the action of cytokines and other factors, in turn, activates the CNS to orchestrate negative-feedback mechanisms that keep the immune response in check. Disruption of these interactions has been associated with a number of syndromes including inflammatory, autoimmune, and cardiovascular diseases, metabolic and psychiatric disorders, and the development of shock. The hypothalamic-pituitary-gonadal axis also plays an important part in regulating immunity through the secretion of sex hormones. Although numerous studies have established a role for immunomodulation by estrogen and testosterone, the role of progesterone is less well understood. Progesterone is crucial for reproductive organ development and maintenance of pregnancy, and more recent studies have clearly shown its role as an important immune regulator. The main focus of this review will be about the role of steroid hormones, specifically glucocorticoids and progesterone, in inflammatory responses and infectious diseases and how dysregulation of their actions may contribute to development of autoimmune and inflammatory disease.

Association between birth weight in preterm neonates and the BclI polymorphism of the glucocorticoid receptor gene

Endogenous and exogenous glucocorticoids influence fetal growth and development, and maternal administration of synthetic glucocorticoids may decrease the risk of perinatal morbidity including lung disease in preterm neonates. Because polymorphisms of the glucocorticoid receptor gene are known to influence the sensitivity to glucocorticoids, in the present study we examined whether any associations could exist among the BclI, N363S and ER22/23EK polymorphisms of the glucocorticoid receptor gene and gestational age, birth weight and/or perinatal morbidity of 125 preterm neonates born at 28-35 weeks' gestation with (n=57) or without maternal dexamethasone treatment (n=68). The prevalence of the three polymorphisms in the whole group of preterm infants was similar to that reported in healthy adult Hungarian population. However, we found that the BclI polymorphism significantly associated with higher birth weight adjusted for the gestational age (p=0.004, ANOVA analysis). None of the three polymorphisms showed an association with perinatal morbidities, including necrotizing enterocolitis, intraventricular hemorrhagia, patent ductus arteriosus, respiratory distress syndrome, bronchopulmonary dysplasia and sepsis in the two groups of preterm neonates with and without maternal dexamethasone treatment. These results suggest that the BclI polymorphism of the glucocorticoid receptor gene may have an impact on gestational age-adjusted birth weight, but it does not influence perinatal morbidities of preterm neonates.

A common intron 2 polymorphism of the glucocorticoid receptor gene is associated with insulin resistance in men

OBJECTIVE

Clinical similarities between the metabolic syndrome and Cushing's syndrome have led to speculation of genetic association between them. The Bcl1 polymorphism in intron 2 of the glucocorticoid receptor (GR) gene has been associated with insulin resistance/hyperinsulinaemia. Our objective was to test the association of rs2918419, a T-->C single nucleotide change in intron 2 downstream of the Bcl1 locus, with components of the metabolic syndrome and its interaction with the Bcl1 locus.

DESIGN AND METHODS

We genotyped a subsample of 325 White subjects (116 men) in the Newcastle Heart Project (NHP), a population-based study in north-east England. Gender-specific statistical analysis by stepwise backward multiple regression was performed to test the association of allele status with adiposity, glucose and insulin responses to oral glucose tolerance test (OGTT), fasting lipids and blood pressure.

RESULTS

Minor allele frequency was 0.14 for rs2918419 and 0.39 for the Bcl1 polymorphism. rs2918419 was associated with higher fasting insulin concentration and insulin resistance in men but not in women. Contrary to earlier studies, the Bcl1 polymorphism on its own was not associated with insulin resistance/hyperinsulinaemia in either gender. Subjects carrying variant rs2918419 alleles also had variant alleles at the Bcl1 locus. In men, but not women, Bcl1 variant alleles on a background of rs2918419 wild-type alleles associated with lower fasting insulin compared to wild-type alleles at both loci or variant alleles at both loci.

CONCLUSIONS

We report that rs2918419 was linked with hyperinsulinaemia and insulin resistance in men. Carrying Bcl1 variant alleles without rs2918419 was not associated with hyperinsulinaemia/insulin resistance. Previous reports of the association of Bcl1 polymorphism with obesity-related characteristics may reflect linkage disequilibrium with rs2918419.

The 23K variant of the R23K polymorphism in the glucocorticoid receptor gene protects against postnatal growth failure and insulin resistance after preterm birth

CONTEXT

Preterm birth is associated with postnatal growth failure, abdominal fat accumulation, insulin resistance, and hypertension, resembling increased glucocorticoid bioactivity.

OBJECTIVE

We tested the effects of the R23K and N363S polymorphisms in the glucocorticoid receptor gene, associated with decreased and increased sensitivity to cortisol, respectively, on linear growth and the adult metabolic profile in a cohort (n = 249) of men and women born less than 32 gestational weeks and followed up prospectively from birth until 19 yr of age.

DESIGN AND PARTICIPANTS

This was a birth cohort study that included 249 19-yr-old survivors born at a gestational age less than 32 wk from the Dutch Project on Preterm and Small-for-Gestational-Age Infants cohort.

SETTING

This project was a nationwide multicenter follow-up study.

MAIN OUTCOME MEASURES

Linear growth and adult body composition, fasting cortisol, glucose, insulin, and cholesterol concentrations, and blood pressure were measured.

RESULTS

The 23K variant (n = 24) was associated with lower fasting insulin levels [mean difference after log transformation: -0.09 (95% confidence interval -0.16, -0.01) mU/liter] and a lower homeostatic model assessment for insulin resistance index [mean difference after log transformation: -0.09 (95% confidence interval -0.16, -0.01)] as well as with a taller stature departing from the age of 1 yr onward. 23K carriers showed complete catch-up growth between the ages of 3 months and 1 yr, and attained height was similar to the population reference mean, whereas stature in noncarriers was on average 0.5 sd below this mean. In contrast, the N363S polymorphism was not associated with any of the outcomes.

CONCLUSIONS

Carriers of the 23K variant are, at least in part, protected against postnatal growth failure and insulin resistance after preterm birth.