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

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.

Mineralocorticoid receptor and glucocorticoid receptor work alone and together in cell-type-specific manner: Implications for resilience prediction and targeted therapy

‘You can't roll the clock back and reverse the effects of experiences' Bruce McEwen used to say when explaining how allostasis labels the adaptive process. Here we will for once roll the clock back to the times that the science of the glucocorticoid hormone was honored with a Nobel prize and highlight the discovery of their receptors in the hippocampus as inroad to its current status as master regulator in control of stress coping and adaptation. Glucocorticoids operate in concert with numerous neurotransmitters, neuropeptides, and other hormones with the aim to facilitate processing of information in the neurocircuitry of stress, from anticipation and perception of a novel experience to behavioral adaptation and memory storage. This action, exerted by the glucocorticoids, is guided by two complementary receptor systems, mineralocorticoid receptors (MR) and glucocorticoid receptors (GR), that need to be balanced for a healthy stress response pattern. Here we discuss the cellular, neuroendocrine, and behavioral studies underlying the MR:GR balance concept, highlight the relevance of hypothalamic-pituitary-adrenal (HPA) -axis patterns and note the limited understanding yet of sexual dimorphism in glucocorticoid actions. We conclude with the prospect that (i) genetically and epigenetically regulated receptor variants dictate cell-type-specific transcriptome signatures of stress-related neuropsychiatric symptoms and (ii) selective receptor modulators are becoming available for more targeted treatment. These two new developments may help to ‘restart the clock’ with the prospect to support resilience.

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.

A 646C > G (rs41423247) polymorphism of the glucocorticoid receptor as a risk factor for hyperglycaemia diagnosed in pregnancy-data from an observational study

AIM

Hyperglycaemia diagnosed in pregnancy (HiP) is a serious and frequent complication of pregnancy, increasing the risk for adverse maternal and neonatal outcomes. Investigate whether allelic variations of the glucocorticoid receptor are related to an increased risk of HiP.

METHOD

The following polymorphisms of the glucocorticoid receptor (GR) were investigated in the cohort study of N = 197 pregnant women with HiP and N = 133 normoglycemic pregnant controls: 646C > G (rs41423247), N363S (rs6195), ER23/22EK (rs6190, rs6189).

RESULTS

A GG variant of the rs41423247 polymorphism was associated with a significantly higher risk for HiP: OR 1.94 (1.18; 3.18), p = 0.009. The relationship remained significant after controlling for maternal age and prepregnancy BMI: OR 3.09 (1.25; 7.64), p = 0.014.

CONCLUSIONS

The allelic GG variant of the 646C > G (rs41423247) polymorphism is associated with an increased risk for hyperglycaemia in pregnancy.

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.

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.

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.

Glucocorticoids mobilize macrophages by transcriptionally up-regulating the exopeptidase DPP4

Glucocorticoids are potent endogenous anti-inflammatory molecules, and their cognate receptor, glucocorticoid receptor (GR), is expressed in nearly all immune cells. Macrophages are heterogeneous immune cells having a central role in both tissue homeostasis and inflammation and also play a role in the pathogenesis of some inflammatory diseases. Paradoxically, glucocorticoids have only a limited efficacy in controlling the resolution of these macrophage-related diseases. Here, we report that the transcriptomes of monocyte-like THP-1 cells and macrophage-like THP-1 cells (THP1-MΦ) have largely conserved gene expression patterns. In contrast, the differentiation to THP1-MΦ significantly altered the sensitivity of gene transcription to glucocorticoids. Among glucocorticoid-regulated genes, we identified the exopeptidase dipeptidyl peptidase-4 (DPP4) as a critical glucocorticoid-responsive gene in THP1-MΦ. We found that GR directly induces DPP4 gene expression by binding to two glucocorticoid-responsive elements (GREs) within the DPP4 promoter. Additionally, we show that glucocorticoid-induced DPP4 expression is blocked by the GR antagonist RU-486 and by GR siRNA transfection and that DPP4 enzyme activity is reduced by DPP4 inhibitors. Of note, glucocorticoids highly stimulated macrophage mobility; unexpectedly, DPP4 mediated the glucocorticoid-induced macrophage migration, and siRNA-mediated knockdowns of GR and DPP4 blocked dexamethasone-induced THP1-MΦ migration. Moreover, glucocorticoid-induced DPP4 activation was also observed in proinflammatory M1-polarized murine macrophages, as well as peritoneal macrophages, and was associated with increased macrophage migration. Our results indicate that glucocorticoids directly up-regulate DPP4 expression and thereby induce migration in macrophages, potentially explaining why glucocorticoid therapy is less effective in controlling macrophage-dominated inflammatory disorders.

Transethnic associations among immune-mediated diseases and single-nucleotide polymorphisms of the aryl hydrocarbon response gene ARNT and the PTPN22 immune regulatory gene

BACKGROUND

Because immune responses are sensitive to environmental changes that drive selection of genetic variants, we hypothesized that polymorphisms of some xenobiotic response and immune response genes may be associated with specific types of immune-mediated diseases (IMD), while others may be associated with IMD as a larger category regardless of specific phenotype or ethnicity.

OBJECTIVE

To examine transethnic gene-IMD associations for single nucleotide polymorphism (SNP) frequencies of prototypic xenobiotic response genes-aryl hydrocarbon receptor (AHR), AHR nuclear translocator (ARNT), AHR repressor (AHRR) - and a prototypic immune response gene, protein tyrosine phosphatase, non-receptor type 22 (PTPN22), in subjects from the Environmental Polymorphisms Registry (EPR).

METHODS

Subjects (n = 3731) were genotyped for 14 SNPs associated with functional variants of the AHR, ARNT, AHRR, and PTPN22 genes, and their frequencies were compared among African Americans (n = 1562), Caucasians (n = 1838), and Hispanics (n = 331) with previously reported data. Of those genotyped, 2015 EPR subjects completed a Health and Exposure survey. SNPs were assessed via PLINK for associations with IMD, which included those with autoimmune diseases, allergic disorders, asthma, or idiopathic pulmonary fibrosis. Transethnic meta-analyses were performed using METAL and MANTRA approaches.

RESULTS

ARNT SNP rs11204735 was significantly associated with autoimmune disease by transethnic meta-analyses using METAL (odds ratio, OR [95% confidence interval] = 1.29 [1.08-1.55]) and MANTRA (ORs ranged from 1.29 to 1.30), whereas ARNT SNP rs1889740 showed a significant association with autoimmune disease by METAL (OR = 1.25 [1.06-1.47]). For Caucasian females, PTPN22 SNP rs2476601 was significantly associated with autoimmune disease by allelic association tests (OR = 1.99, [1.30-3.04]). In Caucasians and Caucasian males, PTPN22 SNP rs3811021 was significantly associated with IMD (OR = 1.39 [1.12-1.72] and 1.50 [1.12-2.02], respectively) and allergic disease (OR = 1.39 [1.12-1.71], and 1.62 [1.19-2.20], respectively). In the transethnic meta-analysis, PTPN22 SNP rs3811021 was significantly implicated in IMD by METAL (OR = 1.31 [1.10-1.56]), and both METAL and MANTRA suggested that rs3811021 was associated with IMD and allergic disease in males across all three ethnic groups (IMD METAL OR = 1.50 [1.15-1.95]; IMD MANTRA ORs ranged from 1.47 to 1.50; allergic disease METAL OR = 1.58 [1.20-2.08]; allergic disease MANTRA ORs ranged from 1.55 to 1.59).

CONCLUSIONS

Some xenobiotic and immune response gene polymorphisms were shown here, for the first time, to have associations across a broad spectrum of IMD and ethnicities. Our findings also suggest a role for ARNT in the development of autoimmune diseases, implicating environmental factors metabolized by this pathway in pathogenesis. Further studies are needed to confirm these data, assess the implications of these findings, define gene-environment interactions, and explore the mechanisms leading to these increasingly prevalent disorders.

Drug-induced hyperglycaemia and diabetes: pharmacogenomics perspectives

Drug-induced diabetes is widely reported in clinical conditions, and it is becoming a global issue because of its potential to increase the risk of severe cardiovascular complications. However, which drug mechanisms exert their diabetogenic effects and why the effects present significant inter-individual differences remain largely unknown. Pharmacogenomics, which is the study of how genomic variation influences drug responses, provides an explanation for individual differences in drug-induced diabetes. We highlight that pharmacogenomics can be involved in regulating the expression of genes in signaling pathways related to the pharmacokinetics or pharmacodynamics of drugs or the pathogenesis of diabetes, contributing to the differences in drug-induced glucose impairment. The pharmacogenomics studies of the major diabetogenic drugs are reviewed, including calcineurin inhibitors, antipsychotics, hormones, and antihypertensive drugs. We intend to elucidate the genetic basis of drug-induced diabetes and pave the way for the precise use of these drugs in the clinic.

Stress and Obesity: Are There More Susceptible Individuals?

PURPOSE OF REVIEW

Stress has long been suspected to be interrelated to (abdominal) obesity. However, interindividual differences in this complex relationship exist. We suggest that the extent of glucocorticoid action partly explains these interindividual differences. We provide latest insights with respect to multiple types of stressors.

RECENT FINDINGS

Increased long-term cortisol levels, as measured in scalp hair, are strongly related to abdominal obesity and to specific mental disorders. However, not all obese patients have elevated cortisol levels. Possibly, the interindividual variation in glucocorticoid sensitivity, which is partly genetically determined, may lead to higher vulnerability to mental or physical stressors. Other evidence for the important role for increased glucocorticoid action is provided by recent studies investigating associations between body composition and local and systemic corticosteroids. Stress may play a major role in the development and maintenance of obesity in individuals who have an increased glucocorticoid exposure or sensitivity. These insights may lead to more effective and individualized obesity treatment strategies.

Generating diversity in human glucocorticoid signaling through a racially diverse polymorphism in the beta isoform of the glucocorticoid receptor

Alternative splicing of the human glucocorticoid receptor gene generates two isoforms, hGRα and hGRβ. hGRβ functions as a dominant-negative regulator of hGRα activity and but also has inherent transcriptional activity, collectively altering glucocorticoid sensitivity. Single-nucleotide polymorphisms in the 3' UTR of hGRβ have been associated with altered receptor protein expression, glucocorticoid sensitivity, and disease risk. Characterization of the hGRβ G3134T polymorphism has been limited to a relatively small, homogenous population. The objective of this study was to determine the prevalence of hGRβ G3134T in a diverse population and assess the association of hGRβ G3134T in this population with physiological outcomes. In a prospective cohort study, 3730 genetically diverse participants were genotyped for hGRβ G3134T and four common GR polymorphisms. A subset of these participants was evaluated for clinical and biochemical measurements. Immortalized human osteosarcoma cells (U-2 OS), stably transfected with wild-type or G3134T hGRβ, were evaluated for receptor expression, stability, and genome-wide gene expression. Glucocorticoid-mediated gene expression profiles were investigated in primary macrophages isolated from participants. In a racially diverse population, the minor allele frequency was 74% (50.7% heterozygous carriers and 23.3% homozygous minor allele), with a higher prevalence in Caucasian non-Hispanic participants. After adjusting for confounding variable, carriers of hGRβ G3134T were more likely to self-report allergies, have higher serum cortisol levels, and reduced cortisol suppression in response to low-dose dexamethasone. The presence of hGRβ G3134T in U-2 OS cells increased hGR mRNA stability and protein expression. Microarray analysis revealed that the presence of the hGRβ G3134T polymorphism uniquely altered gene expression profiles in U-2 OS cells and primary macrophages. hGRβ G3134T is significantly present in the study population and associated with race, self-reported disease, and serum levels of glucocorticoids. Underlying these health differences may be changes in gene expression driven by altered receptor stability.