A 5-Year Follow-Up Study of 3 Polymorphisms in the Human Glucocorticoid Receptor Gene in Relation to Obesity, Hypertension, and Diabetes

Glucocorticoid Receptor Gene (NR3C1) Polymorphisms and Metabolic Syndrome: Insights from the Mennonite Population

The regulation of the hypothalamic-pituitary-adrenal (HPA) axis is associated with polymorphisms and the methylation degree of the glucocorticoid receptor gene (NR3C1) and is potentially involved in the development of metabolic syndrome (MetS). In order to evaluate the association between MetS with the polymorphisms, methylation, and gene expression of the NR3C1 in the genetically isolated Brazilian Mennonite population, we genotyped 20 NR3C1 polymorphisms in 74 affected (MetS) and 138 unaffected individuals without affected first-degree relatives (Co), using exome sequencing, as well as five variants from non-exonic regions, in 70 MetS and 166 Co, using mass spectrometry. The methylation levels of 11 1F CpG sites were quantified using pyrosequencing (66 MetS and 141 Co), and the NR3C1 expression was evaluated via RT-qPCR (14 MetS and 25 Co). Age, physical activity, and family environment during childhood were associated with MetS. Susceptibility to MetS, independent of these factors, was associated with homozygosity for rs10482605*C (OR = 4.74, pcorr = 0.024) and the haplotype containing TTCGTTGATT (rs3806855*T_ rs3806854*T_rs10482605*C_rs10482614*G_rs6188*T_rs258813*T_rs33944801*G_rs34176759*A_rs17209258*T_rs6196*T, OR = 4.74, pcorr = 0.048), as well as for the CCT haplotype (rs41423247*C_ rs6877893*C_rs258763*T), OR = 6.02, pcorr = 0.030), but not to the differences in methylation or gene expression. Thus, NR3C1 polymorphisms seem to modulate the susceptibility to MetS in Mennonites, independently of lifestyle and early childhood events, and their role seems to be unrelated to DNA methylation and gene expression.

Genetic polymorphisms of glucocorticoid receptor and their association with new-onset diabetes mellitus in kidney transplant recipients

INTRODUCTION

The variability in developing New-onset Diabetes Mellitus After Transplantation (NODAT), together with previously well-established interindividual variation in glucocorticoid sensitivity, led us to hypothesize that polymorphisms in the NR3C1 gene encoding glucocorticoid receptor may alter glucose balance in kidney transplant recipients. This study aimed to evaluate the association of three functional polymorphisms, BclI, N363S, and ER22/23EK, on the NR3C1 gene with NODAT in kidney allograft recipients.

METHODS

From Jun 2020 to July 2022 in Shiraz, 52 patients with NODAT (case group) and 52 non-diabetic kidney transplant recipients (control group) were randomly screened and recruited in this case-control study. The PCR-RFLP technique determined the genotypes of BclI, N363S, and ER22/23EK polymorphisms.

RESULTS

The allelic frequencies of the mutant alleles of BclI, N363S, and ER22/23EK polymorphisms in all patients were 0.36, 0.03, and 0.009, respectively. BclI mutant genotypes (CG and GG) were significantly associated with an increased risk of NODAT (P = 0.016), while the two other polymorphisms disclosed no significant association with NODAT development. In the case group, no significant association was detected between the onset time of NODAT and studied polymorphisms, including BclI (P = 0.43), N363S (P = 0.30), and ER22/23EK. P value was not reported for the last polymorphism because all patients with NODAT had the wild-type genotype (GG/GG) and performing statistical analysis was not feasible. Among studied demographic/clinical/paraclinical variables, factors such as higher mean trough level of tacrolimus during the first month after transplantation and higher mean daily dose of prednisolone significantly linked with NODAT development.

CONCLUSION

Our data suggested that BclI polymorphism significantly affects NODAT development among Iranian kidney allograft recipients.

[Association of the structure of the glucocorticoid receptor and single nucleotide NR3C1 gene polymorphisms with metabolic disorders]

Glucocorticoid therapy is widely used in the treatment of various pathologies. Sensitivity to glucocorticoids  (GC) has a serious impact not only on the effectiveness of their action, but also on the severity of side effects, the formation of risk factors and the development  of cardiovascular diseases (CVD). Variability of sensitivity to GC causes different phenotypes and severity of metabolic disorders underlying  CVD. Among  them, one can distinguish  a decrease in muscle mass and strength, obesity, glucose and lipid metabolism impairment, and others. Glucocorticoids carry out their effects by binding to the glucocorticoid receptor (GR), and therefore this is considered a critical point in their action. This review presents data on the significance of the glucocorticoid  receptor structure, examines the main single nucleotide polymorphisms (SNP) of the NR3C1 gene associated with hypersensitivity  or relative resistance to glucocorticoids  in the context of metabolic disorders and the development of CVD. The association of the four most studied SNP of the GR gene with metabolic risks is described in detail: BclI (rs41423247), N363S (rs56149945), ER22/23EK (rs6189/rs6190), GR-9ß (rs6198). Their determination can contribute to clarifying the prognosis of both the effectiveness of GC and the development of metabolic disorders, and subsequent early correction of CVD risk factors.

Children with Down syndrome: association of Bcl-I polymorphism of nuclear receptor subfamily 3 group C member 1 gene with obesity

BACKROUND

This study aimed to assess the possible association between rs41423247 (Bcl-I) polymorphism in the gene for the human glucocorticoid receptor (GR) called Nuclear Receptor Subfamily 3 Group C Member 1 (NR3C1) with obesity in Egyptian children with and without Down syndrome.

METHODS

The Bcl-I polymorphism was assessed, using real-time PCR, in 300 children divided into four groups: Down-obese, Down-non obese, normal-obese, and normal non-obese.

RESULTS

There was no significant difference between normal-obese and normal-non obese children regarding the Bcl-I genotypes and allele frequencies, while there was a significant difference between Down-obese and Down-non obese children regarding the Bcl-I GC genotype frequency. Again, there was a highly significant difference between Down-obese and normal-non obese children and between children with Down-syndrome (obese and non-obese) and normal children (obese and non-obese) regarding the Bcl-I genotypes and alleles frequencies.

CONCLUSIONS

Our study found a weak association of the G allele of Bcl-I rs41423247 with the presence of obesity among normal Egyptian children, while there was a significant association of the mutant C allele of the Bcl-I rs41423247 with Down syndrome, suggesting a possible association with Down syndrome pathophysiology.

IMPACT

Bcl-I polymorphism is not strikingly associated with obesity in normal children. The GG genotype is higher in obese normal children but without significant difference. The significant increase of the mutant C allele in Down-children than normal children. This may be relevant to Down syndrome's pathophysiology which disturbs the whole genome's balance.

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.

Adrenal suppression in patients with chronic obstructive pulmonary disease treated with glucocorticoids: Role of specific glucocorticoid receptor polymorphisms

BACKGROUND

Single-nucleotide polymorphisms (SNPs) of the glucocorticoid receptor (GR) gene NR3C1 have been associated with an altered sensitivity to glucocorticoids, and thus may alter the therapeutic effects of glucocorticoids. We investigated the prevalence of adrenal suppression after treatment with glucocorticoids and evaluated whether GR SNPs were associated with altered risks of adrenal suppression and metabolic disorders in patients with chronic obstructive pulmonary disease (COPD).

METHODS

In an observational prospective cohort study, we recruited 78 patients with severe COPD receiving 5 days glucocorticoid treatment for an exacerbation of COPD. In total, 55% of these patients were also receiving regular inhaled corticosteroids (ICS). Adrenal function was evaluated with a corticotropin test 30 days after the exacerbation. Patients were genotyped for Bcl1, N363S, ER22/23EK, and 9β SNPs.

RESULTS

The prevalence of adrenal suppression (corticotropin-stimulated plasma-cortisol ≤ 420 nmol/L) 30 days after glucocorticoid treatment was 4/78 (5%). There was no difference between carriers and non-carriers of the polymorphisms (Bcl1, 9β, ER22/23K, and N363S) in corticotropin stimulated plasma-cortisol concentrations. In the haplotype analyses, we included the 50 patients who had a high-sensitivity (76%), a low-sensitivity (4%), or a wild-type (20%) GR haplotype. There was no difference in the frequency of adrenal suppression or metabolic disorders between the two stratified groups: (a) high-sensitivity (Bcl1 and/or N363S) haplotypes vs. (b) low-sensitivity (9β and/or ER22/23K) plus wild-type haplotypes (p > 0.05). Carriers of the high-sensitivity GR gene haplotype exhibited a steeper decline in stimulated P-cortisol with increased ICS dose (slope, -1.35 vs. 0.94; p = 0.17), compared to the group with low-sensitivity or wild-type haplotypes, respectively.

CONCLUSIONS

In total, 5% of patients exhibited insufficient adrenal function. The Bcl1 and N363S polymorphisms did not seem to increase the risk of glucocorticoid suppression or metabolic disorders in adults treated with glucocorticoids for COPD exacerbations.

NR3C1 Glucocorticoid Receptor Gene Polymorphisms Are Associated with Membranous and IgA Nephropathies

Glomerular diseases (GNs) are responsible for approximately 20% of chronic kidney diseases. Glucocorticoid receptor gene (NR3C1) single nucleotide polymorphisms (SNPs) are implicated in differences in predisposition to autoimmunity and steroid sensitivity. The aim of this study was to evaluate the frequency of the NR3C1 SNPs—rs6198, rs41423247 and rs17209237—in 72 IgA nephropathy (IgAN) and 38 membranous nephropathy (MN) patients compared to 175 healthy controls and to correlate the effectiveness of treatment in IgAN and MN groups defined as a reduction of proteinuria <1 g/24 h after 12 months of treatment. Real-time polymerase chain reactions and SNP array-based typing were used. We found significant rs41423247 association with MN (p = 0.026); a significant association of rs17209237 with eGFR reduction after follow-up period in all patients with GNs (p = 0.021) and with the degree of proteinuria after 1 year of therapy in all patients with a glomerulopathy (p = 0.013) and IgAN (p = 0.021); and in the same groups treated with steroids (p = 0.021; p = 0.012). We also observed the association between rs41423247 and IgAN histopathologic findings (p = 0.012). In conclusion, our results indicate that NR3C1 polymorphisms may influence treatment susceptibility and clinical outcome in IgAN and MN.

Glucocorticoid Receptor Signaling in Diabetes

Stress and depression increase the risk of Type 2 Diabetes (T2D) development. Evidence demonstrates that the Glucocorticoid (GC) negative feedback is impaired (GC resistance) in T2D patients resulting in Hypothalamic-Pituitary-Adrenal (HPA) axis hyperactivity and hypercortisolism. High GCs, in turn, activate multiple aspects of glucose homeostasis in peripheral tissues leading to hyperglycemia. Elucidation of the underlying molecular mechanisms revealed that Glucocorticoid Receptor (GR) mediates the GC-induced dysregulation of glucose production, uptake and insulin signaling in GC-sensitive peripheral tissues, such as liver, skeletal muscle, adipose tissue, and pancreas. In contrast to increased GR peripheral sensitivity, an impaired GR signaling in Peripheral Blood Mononuclear Cells (PBMCs) of T2D patients, associated with hyperglycemia, hyperlipidemia, and increased inflammation, has been shown. Given that GR changes in immune cells parallel those in brain, the above data implicate that a reduced brain GR function may be the biological link among stress, HPA hyperactivity, hypercortisolism and hyperglycemia. GR polymorphisms have also been associated with metabolic disturbances in T2D while dysregulation of micro-RNAs—known to target GR mRNA—has been described. Collectively, GR has a crucial role in T2D, acting in a cell-type and context-specific manner, leading to either GC sensitivity or GC resistance. Selective modulation of GR signaling in T2D therapy warrants further investigation.

Association between NR3C1 gene polymorphisms and age-related hearing impairment in Qingdao Chinese elderly

BACKGROUND

Age-related hearing impairment (ARHI) has attracted increasing attention recently. It is caused by genetic and environmental factors. A number of ARHI-related genes have been found. This study aimed to detect the potential association between NR3C1 gene polymorphisms and ARHI by means of weighted allele score.

METHODS

A total of 861 participants from Qingdao city were selected by means of cluster random sampling. We statistically evaluated the characteristics of individuals and used the Mann-Whitney U test or chi-square test for comparison. The publicly available expression quantitative trait locus (eQTL) was queried on the website of the Genotype-Tissue Expression (GTEx). We used the weighted allele score and logistic regression analysis to explore the association between NR3C1 gene polymorphisms and ARHI. Finally, the prediction model was constructed by logistic regression and receiver operating characteristic (ROC) curve.

RESULTS

All individuals over 60 years of age were enrolled in this study. The allele of rs61757411, rs41423247 and rs6877893 were significantly different between the ARHI group and the normal hearing group (P < 0.01). Though eQTL analysis, rs6877893 and rs33388 might affect the occurrence of ARHI by affecting the expression of NR3C1 gene in artery aorta. Then we performed two models: one without adding any covariates into model and the other adjusting for demographic characteristic, smoking and drinking, diet and exercise, and physical conditions. In the multivariate-adjusted model 2, the odds ratio with 95% confidence interval for weighted allele score (NR3C1) was 0.841 (0.710-0.995, P = 0.043). The area under the ROC curve was 0.755, indicating that the model had good predictability.

CONCLUSIONS

Our study suggests that NR3C1 gene polymorphisms was significantly associated with ARHI.

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.

The association of cortisol levels with leukocyte distribution is disrupted in the metabolic syndrome

BACKGROUND

Leukocyte glucocorticoid sensitivity (GCS) pertains to the responsivity of leukocytes to the regulating actions of glucocorticoids, such as cortisol. Impaired endocrine regulation may link the metabolic syndrome (MetS) to the development of cardiovascular disease. We tested if the physiological association between endogenous cortisol levels and peripheral leukocyte composition becomes disrupted in individuals with MetS.

METHODS

MetS was assessed among 689 German industrial employees. The covariance between cortisol levels and hematologic parameters (i.e., proportions of neutrophils and lymphocytes) and their ratio was explored, which has been proposed as a proxy for GCS in vivo. Cortisol level before blood collection was assessed by repeated saliva collection, and the area under the curve was calculated. Linear regression models were adjusted for potential confounders including age, gender, BMI, income, and lifestyle factors.

RESULTS

Cortisol levels did not differ between subgroups. Participants without MetS (n = 552) showed the expected association of cortisol with hematologic parameters (β = 0.207 to 0.216; p values < 0.001). No association (β = 0.078 to 0.083; p values > 0.10) was found among those with MetS (n = 137), consistent with a reduced GCS. Analyses of separate MetS components showed that reduced GCS was associated specifically with decreased high-density lipoprotein and elevated fasting plasma glucose.

CONCLUSIONS

Utilizing a novel statistical approach to infer GCS, this study provided first epidemiological evidence of aberrant physiological regulation of leukocyte distribution by endogenous cortisol levels among individuals with MetS. These findings underline the idea that MetS may involve disruption of endocrine-immune regulation.

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.

Pathophysiology of Glucocorticoid Signaling

Glucocorticoids (GC), such as cortisol or dexamethasone, control various physiological functions, notably those involved in development, metabolism, inflammatory processes and stress, and exert most of their effects upon binding to the glucocorticoid receptor (GR, encoded by NR3C1 gene). GC signaling follows several consecutive steps leading to target gene transactivation, including ligand binding, nuclear translocation of ligand-activated GR complexes, DNA binding, coactivator interaction and recruitment of functional transcriptional machinery. Any step may be impaired and may account for altered GC signaling. Partial or generalized glucocorticoid resistance syndrome may result in a reduced level of functional GR, a decreased hormone affinity and binding, a defect in nuclear GR translocation, a decrease or lack of DNA binding and/or post-transcriptional GR modifications. To date, 26 loss-of-function NR3C1 mutations have been reported in the context of hypertension, hirsutism, adrenal hyperplasia or metabolic disorders. These clinical signs are generally associated with biological features including hypercortisolism without negative regulatory feedback loop on the hypothalamic-pituitary-adrenal axis. Patients had often low plasma aldosterone and renin levels despite hypertension. Only one GR gain-of-function mutation has been described associating Cushing's syndrome phenotype with normal urinary-free cortisol. Some GR polymorphisms (ER22/23EK, GR-9β) have been linked to glucocorticoid resistance and a healthier metabolic profile whereas some others seemed to be associated with GC hypersensitivity (N363S, BclI), increasing cardiovascular risk (diabetes type 2, visceral obesity). This review focuses on the earlier findings on the pathophysiology of GR signaling and presents criteria facilitating identification of novel NR3C1 mutations in selected patients.

BclI Glucocorticoid Receptor Polymorphism in Relation to Arterial Stiffening and Cardiac Structure and Function: The Hoorn and CODAM Studies

BACKGROUND

Chronic glucocorticoid excess is associated with arterial stiffening and cardiac dysfunction. The BclI glucocorticoid receptor (GR) polymorphism increases GR sensitivity and is associated with a higher body mass index (BMI) and some proxies for cardiovascular disease (CVD). Whether BclI influences arterial stiffening and cardiac dysfunction is currently unknown. Therefore, the aim of the present study was to investigate the association of the BclI polymorphism with arterial stiffening and cardiac structure and function.

METHODS

We conducted an observational cohort study, combining 2 cohort studies designed to investigate genetic and metabolic determinants of CVD. We genotyped 1,124 individuals (age: 64.7 ± 8.5 years) from the Hoorn study and Cohort on Diabetes and Atherosclerosis Maastricht (CODAM) study for BclI. Several arterial stiffening indices of the carotid (Hoorn and CODAM study), brachial and femoral artery and the carotid-femoral pulse wave velocity (Hoorn study only) were determined. In addition, in the Hoorn study, we determined several variables of cardiac structure and function.

RESULTS

We identified 155 homozygous carriers (GG), 498 heterozygous carriers (CG), and 471 noncarriers (CC) of the BclI polymorphism. BclI genotypes did not display significant differences in variables of arterial stiffening (e.g., carotid distensibility coefficient (DC): 12.41 ± 5.37 vs. 12.87 ± 5.55 10-3/kPa [mean ± SD]; P = 0.38; homozygous vs. noncarriers). In addition, no clear differences in estimates of cardiac structure and function were found.

CONCLUSIONS

Even though BclI is associated with a higher BMI and some proxies of CVD, our results do not support the concept that BclI carrier status is associated with greater arterial stiffening or cardiac dysfunction.

The role of glucocorticoid receptors in metabolic syndrome and psychiatric illness

Glucocorticoids (GCs) are involved in a large number of the physiological changes associated with metabolic syndrome and certain psychiatric illness. Although significance is often given to the concentration of GC, its biological action is determined by the activation of intracellular GC receptors (GR). Genetic polymorphisms of the GR and the large array of GR related cofactors can directly or indirectly affect the pathophysiology and evolution of these conditions. This review will discuss the effects of GR mutations on metabolic syndrome and psychotic depression.

Role of GNB3, NET, KCNJ11, TCF7L2 and GRL genes single nucleotide polymorphism in the risk prediction of type 2 diabetes mellitus

Type 2 diabetes (T2DM) is a polygenic metabolic disorder characterized by hyperglycemia occurring as a result of impaired insulin secretion or insulin resistance. Various environmental and genetic factors interact and increase the risk of T2DM and its complications. Among the various genetic factors associated with T2DM, single nucleotide polymorphism in different candidate genes have been studied intensively and the resulting genetic variants have been found to have either positive or negative association with T2DM thereby increasing or decreasing the risk of T2DM, respectively. In this review, we will focus on Guanine nucleotide-binding protein subunit beta 3 (GNB3), Norepinephrine Transporter (NET), Potassium Channel gene (KCNJ11), Transcription Factor 7-Like 2 (TCF7L2) and Glucocorticoid receptor (GRL) genes and their association with T2DM studied in different ethnic groups. The products of these genes are involved in the biochemical pathway leading to T2DM. Polymorphisms in these genes have been intensively studied in individuals of different ethnic origins. Results show that genetic variants of TCF7L2 and KCNJ11 genes have potential to emerge as a risk biomarker for T2DM whereas results of GNB3, GRL and NET genes have been controversial when studied in individuals of different ethnicities. We have tried to summarize the results generated globally in context to the selected genes which could possibly help researchers working in this field and would eventually help in understanding the mechanistic pathways of T2DM leading early diagnosis and prevention.

Polymorphisms of the GR and HSD11B1 genes influence body mass index and weight gain during hormone replacement treatment in patients with Addison's disease

OBJECTIVE

Glucocorticoid substitution is essential in patients with chronic primary adrenocortical insufficiency (Addison's disease) and both over-treatment and inadequate dosage have deleterious effects. Individual sensitivity to glucocorticoids is partly genetically determined.

CONTEXT

To test the hypothesis whether the well-characterized SNPs of the GR and HSD11B1 genes may modulate the individual sensitivity to exogenous glucocorticoids and may influence clinical and/or laboratory parameters and the glucocorticoid substitution dosage in patients with Addison's disease.

PATIENTS AND METHODS

68 patients with primary adrenocortical insufficiency were involved. Clinical and laboratory data, as well as the dosage of the hormone replacement therapy were collected. Peripheral blood DNA was isolated, and the GR and HSD11B1 SNPs were examined using allele-specific PCR or Taqman assay on Real Time PCR.

RESULTS

The allele frequency of the GR N363S polymorphism was higher in patients compared to the control group and the disease appeared significantly earlier in patients harbouring the GR A3669G compared to noncarriers. These patients had higher ACTH level measured at the time of diagnosis. Homozygous BclI carriers had higher body mass index (BMI) and lower total hydrocortisone equivalent supplementation dose needed than heterozygous or noncarriers. The BMI and weight gain during hormone replacement therapy were also higher in carriers of the HSD11B1 rs4844880 treated with glucocorticoids other than dexamethasone.

CONCLUSION

The BclI polymorphism of the GR gene and the rs4844880 of the HSD11B1 gene may contribute to weight gain and may affect the individual need of glucocorticoid substitution dose in these patients.

Characterization of clinical and genetic risk factors associated with dyslipidemia after kidney transplantation

We determined the prevalence of dyslipidemia in a Japanese cohort of renal allograft recipients and investigated clinical and genetic characteristics associated with having the disease. In total, 126 patients that received renal allograft transplants between February 2002 and August 2011 were studied, of which 44 recipients (34.9%) were diagnosed with dyslipidemia at 1 year after transplantation. Three clinical factors were associated with a risk of having dyslipidemia: a higher prevalence of disease observed among female than male patients (P = 0.021) and treatment with high mycophenolate mofetil (P = 0.012) and prednisolone (P = 0.023) doses per body weight at 28 days after transplantation. The genetic association between dyslipidemia and 60 previously described genetic polymorphisms in 38 putative disease-associated genes was analyzed. The frequency of dyslipidemia was significantly higher in patients with the glucocorticoid receptor (NR3C1) Bcl1 G allele than in those with the CC genotype (P = 0.001). A multivariate analysis revealed that the NR3C1 Bcl1 G allele was a significant risk factor for the prevalence of dyslipidemia (odds ratio = 4.6; 95% confidence interval = 1.8–12.2). These findings may aid in predicting a patient's risk of developing dyslipidemia.

Glucocorticoid receptor polymorphisms and haplotypes and their expression in health and disease

Cortisol is involved in many physiological processes, including immunosuppressive and anti-inflammatory actions, and therefore cortisol and its synthetic analogs are widely used to treat a large number of diseases. In glucocorticoid treatment, a large variability of clinical responses is observed. This variability may, in part, be ascribed to genetic variation in the glucocorticoid receptor (GR) gene. In this review we present a catalogue of the various single nucleotide polymorphisms (SNPs) in the glucocorticoid receptor gene and their consequences for human health and disease. Many different GR SNP association studies have been described. However, most studies come down to only a few SNPs reported with different annotations. In this review we clarified these different annotations to uniform names. Most associations between GR SNPs and phenotype have been found in body composition, metabolism, the cardiovascular system, the immune system and psychiatric illnesses. However, many associations have not been replicated (yet), and future replication studies and meta-analyses are needed. There is a substantial body of evidence for GR SNPs to have effects on clinical phenotype. However, as most SNP frequencies are low and their variation is within the range of the general population, the impact of a single SNP for health and disease in the general population is probably modest. However, in-depth studying of the molecular mechanisms of repeatedly observed clinical associations could lead to new possibilities for drug development. In particular the development of selective glucocorticoid receptor modulators holds promise.

Genetic and in vivo determinants of glucocorticoid sensitivity in relation to clinical outcome of childhood nephrotic syndrome

Following initial glucocorticoid treatment, the clinical course in children with nephrotic syndrome is highly variable. Intrinsic sensitivity to glucocorticoids might be a determinant of this variability. Functional polymorphisms of the glucocorticoid receptor gene NR3C1 have been associated with either relatively impaired (GR-9β) or increased (BclI) glucocorticoid sensitivity. Here, in a prospective, well-defined cohort of children with nephrotic syndrome, we evaluated both carriage of GR-9β+TthIII-1 and BclI haplotypes in 113 children and a dexamethasone suppression test in 90 children in relation to their clinical outcome over a median follow-up of 4.4 years. Carriers of GR-9β+TthIII-1 had a significantly higher incidence of steroid dependence 13/25 (52%) compared with noncarriers 19/75 (25%) with a hazard ratio adjusted for gender, age, and descent of 3.04 with 95% confidence interval 1.37-6.74. Both first and frequent relapses happened significantly more often in GR-9β+TthIII-1 carriers than in noncarriers. There were no significant differences in therapeutic outcomes between carriers and noncarriers of the BclI haplotype. Results of the dexamethasone test showed no associations with clinical outcome. Thus, the GR-9β+TthIII-1 haplotype of the glucocorticoid receptor gene offers new insights into the clinical course of children with nephrotic syndrome.

Association between blood pressure and DNA methylation of retrotransposons and pro-inflammatory genes

BACKGROUND

Methylation of deoxyribonucleic acid (DNA) is an epigenetic regulator of gene expression that changes with age, but its contribution to aging-related disorders, including high blood pressure (BP), is still largely unknown. We examined the relation of BP to the methylation of retrotransposon sequences of DNA and of selected candidate genes.

METHODS

This investigation included 789 elderly participants in the Normative Aging Study, ranging in age from 55 to 100 years, who had longitudinal measurements of DNA methylation. In these subjects' DNA we measured the proportion of methylated sites in retrotransposable sequences and in pro-inflammatory genes, expressed as the percent of 5-methylated cytosines (%5mC) among all cytosines. From one to four methylation measurements were made for each subject between 1999 and 2009. We fit mixed-effects models, using repeated measures of BP as the outcome and DNA methylation as the explanatory variable, adjusting for confounding variables. We also fit a Bayesian mixed-effects structural equation model to account for heterogeneity in the effects of methylation sites within each gene.

RESULTS

An increase in inter-quartile range (IQR) in the methylation of Alu elements was associated with an increase of 0.97 mm Hg in diastolic blood pressure (DBP) (95% CI 0.32-1.57), but no such association was observed for long interspersed nuclear element-1 (LINE-1). We also found positive associations between DBP and methylation of the genes for toll-like receptor 2 (TLR2) and inducible nitric oxide synthase (iNOS), and a negative association between DBP and methylation of the gene for interferon-γ (IFN-γ). Associations between methylation and systolic blood pressure (SBP) were weaker than those between methylation and DBP. Bayesian mixed-effects structural equation model results were similar for both DBP and SBP models.

CONCLUSIONS

The results of our study suggest that changes in DNA methylation of some pro-inflammatory genes and retrotransposable elements are related to small changes in BP.

Diet and our genetic legacy in the recent anthropocene: a Darwinian perspective to nutritional health

Nutrient-gene research tends to focus on human disease, although such interactions are often a by-product of our evolutionary heritage. This review explores health in this context, reframing genetic variation/epigenetic phenomena linked to diet in the framework of our recent evolutionary past. This "Darwinian/evolutionary medicine" approach examines how diet helped us evolve among primates and to adapt (or fail to adapt) our metabolome to specific environmental conditions leading to major diseases of civilization. This review presents updated evidence from a diet-gene perspective, portraying discord that exists with respect to health and our overall nutritional, cultural, and activity patterns. While Darwinian theory goes beyond nutritional considerations, a significant component within this concept does relate to nutrition and the mismatch between genes, modern diet, obesogenic lifestyle, and health outcomes. The review argues that nutritional sciences should expand knowledge on the evolutionary connection between food and disease, assimilating it into clinical training with greater prominence.

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.

BclI glucocorticoid receptor polymorphism is associated with greater body fatness: the Hoorn and CODAM studies

CONTEXT

The BclI polymorphism in the glucocorticoid receptor (GR) gene is associated with enhanced glucocorticoid (GC) sensitivity.

OBJECTIVE

Our objective was to investigate the association of the BclI polymorphism with body fatness and insulin resistance.

DESIGN AND SETTING

We conducted an observational cohort study, combining data from 2 cohort studies enriched with individuals with impaired glucose metabolism and/or diabetes mellitus type 2 (DM2).

PATIENTS AND METHODS

We examined 1228 participants (mean age 64.7 years, 45% women) from the Cohort Study on Diabetes and Atherosclerosis Maastricht (CODAM, n = 543) and the Hoorn Study (n = 685). Body mass index (BMI), waist and hip circumferences, and waist-to-hip ratio (WHR) were obtained; insulin resistance was estimated using the homeostasis model assessment for insulin resistance (HOMA2-IR).

RESULTS

We identified 519 noncarriers (CC), 540 heterozygous (CG) carriers, and 169 homozygous (GG) carriers of the G-allele of the BclI polymorphism. Homozygous carriers had a higher BMI (28.9 vs 27.9 kg/m(2)) and waist (99.6 vs 97.2 cm) and hip (105.5 vs 103.2 cm) circumference compared with noncarriers, also after adjustment for age, sex, cohort, glucose tolerance, and lifestyle risk factors: β = 0.94 kg/m(2) (95% confidence interval, 0.24-1.63), β = 2.84 cm (0.95;4.73) and β = 2.38 cm (0.88-3.87), respectively. Similar results were obtained when comparing homozygous carriers with heterozygous carriers: β = 1.03 kg/m(2) (0.34-1.72), β = 2.20 cm (0.31-4.08) and β = 1.99 cm (0.51-3.48), respectively. There were no differences in WHR. Ln-HOMA2-IR was higher in GG carriers compared with CG carriers; 0.29 vs 0.17 [β = 0.09 (0.01-0.17)], but this effect was attenuated after adjustment for BMI [β = 0.04 (-0.04 to 0.11)].

CONCLUSION

Homozygous carriers of the BclI polymorphism of the GR gene have significantly greater total body fatness, contributing to higher HOMA2-IR, compared with heterozygous carriers and noncarriers.

Disease gene identification by random walk on multigraphs merging heterogeneous genomic and phenotype data

BACKGROUND

High throughput experiments resulted in many genomic datasets and hundreds of candidate disease genes. To discover the real disease genes from a set of candidate genes, computational methods have been proposed and worked on various types of genomic data sources. As a single source of genomic data is prone of bias, incompleteness and noise, integration of different genomic data sources is highly demanded to accomplish reliable disease gene identification.

RESULTS

In contrast to the commonly adapted data integration approach which integrates separate lists of candidate genes derived from the each single data sources, we merge various genomic networks into a multigraph which is capable of connecting multiple edges between a pair of nodes. This novel approach provides a data platform with strong noise tolerance to prioritize the disease genes. A new idea of random walk is then developed to work on multigraphs using a modified step to calculate the transition matrix. Our method is further enhanced to deal with heterogeneous data types by allowing cross-walk between phenotype and gene networks. Compared on benchmark datasets, our method is shown to be more accurate than the state-of-the-art methods in disease gene identification. We also conducted a case study to identify disease genes for Insulin-Dependent Diabetes Mellitus. Some of the newly identified disease genes are supported by recently published literature.

CONCLUSIONS

The proposed RWRM (Random Walk with Restart on Multigraphs) model and CHN (Complex Heterogeneous Network) model are effective in data integration for candidate gene prioritization.

Glucocorticoid sensitivity in mood disorders

In this review, we provide an overview of recent literature on glucocorticoid (GC) sensitivity in mood disorders. Assessing GC sensitivity is often performed by measuring the cortisol awakening rise (CAR), by challenging the hypothalamic-pituitary-adrenal (HPA) axis using a dexamethasone suppression test (DST) or a dexamethasone/cortisol-releasing hormone test (DEX/CRH); more recently by measuring cortisol as a retrospective calendar in scalp hair. The main findings in mood disorders are higher mean cortisol levels in hair samples and a higher CAR, showing a hyperactivity of the HPA axis. This is in line with the mild resistance for GCs previously observed in challenge tests during mood episodes. GC sensitivity is partly determined by polymorphisms in the genes encoding receptors and other proteins involved in the regulation of the HPA axis. We shortly discuss the glucocorticoid receptor, as well as the mineralocorticoid receptor, the cortisol-releasing hormone receptor-1, and the glucocorticoid receptor co-chaperone FKBP5. Data clearly indicate genetic changes, along with epigenetic changes which influence the set-point and regulation of the HPA axis. Early trauma, as well as influences in utero, appears to be important. Future research is necessary to further clarify the biological background and consequences of an individual's cortisol exposure in relation to mood.

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.