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Background: Genetic variants in immunomodulating genes have been suggested to contribute to the risk of cardiovascular disease. Glucocorticoids are important regulators of inflammatory processes and the immune system. Our aim was to determine the contribution of genetic glucocorticoid receptor variants, with different cortisol sensitivities, to the risk of cardiovascular disease., Methods: The study was conducted in a large (n=7983) population-based, prospective cohort of the Rotterdam Study. The mean duration of follow-up was 8.9 years. Measures of cardiovascular disease were incident myocardial infarction, coronary heart disease, high-sensitivity C-reactive protein level, interleukin 6 level, and arteria carotis intima-media thickness., Results: Persons homozygous for haplotype 3, which is a common variant of the glucocorticoid receptor gene, had a more than 2-fold increased risk of myocardial infarction (hazard ratio, 2.1; 95% confidence interval, 1.13-4.07) and an almost 3-fold increased risk of coronary heart disease (hazard ratio, 2.6; 95% confidence interval, 1.40-4.81) compared with nonhomozygous persons. In addition, their C-reactive protein and interleukin 6 levels were higher, and carotis intima-media thickness was greater. No associations were found for the other haplotypes., Conclusions: The glucocorticoid receptor gene haplotype 3 is a common genetic variant and is related to a more active proinflammatory system. This haplotype is associated with the risk of cardiovascular disease and its parameters. These results should be regarded as hypothesis generating until they have been replicated in other studies. Our findings suggest that genetically determined cortisol sensitivity is involved in the pathogenesis of cardiovascular disease and might identify a subgroup at risk.

The glucocorticoid receptor (GR) is widely expressed in various tissues throughout the human body. At least three different 3'-splice variants of the GR have been reported: GR-alpha, which is functionally active; GR-beta, which is a dominant negative inhibitor of GR-alpha function; and GR-P, which is thought to activate the function of GR-alpha. At least seven different variants for exon 1 exist, 1A-1F and 1H, each with its own promoter. In this study, we explored if tissue-specific splicing of the 3'-end variants of the GR is influenced by alternative promoter usage. cDNAs of different tissues and cell lines were used to investigate which part of transcripts carrying each of the three major variants for exons 1, 1A, 1B, or 1C, encodes for the splice variants GR-alpha, GR-beta, and GR-P. Our data demonstrate that the expression of GR-alpha is preferentially regulated by promoter 1C and that for the expression of GR-P promoter 1B is predominantly used. This indicates that regulation of GR splice variants could partly occur through selective use of the multiple promoters, and that this is another way to sensitize cells and tissues to the different activities of the GR isoforms.

Context: Glucocorticoids (GCs) are extensively used in the treatment of inflammatory and autoimmune diseases. Their beneficial effects are thought to be mediated by GC transrepression on gene expression. However, their use is limited by serious adverse effects, presumably mediated by GC transactivation of gene expression., Objective: The objective of the study was to investigate the effect of the GC receptor haplotype, characterized by the GR-9beta polymorphism, on GC transactivation and transrepression., Design and Methods: This was a cross-sectional study in 216 persons randomly selected from participants in The Rotterdam Study, a population-based cohort study in the elderly. Clinical and biochemical parameters of GC sensitivity were measured: weight, height, waist to hip ratio, glucose, insulin, total cholesterol, high-density lipoprotein, and C-reactive protein. In a dexamethasone suppression test, the response of serum cortisol concentrations was studied. Genotyping for four GC receptor polymorphisms was performed. In addition, ex vivo experiments were performed with leukocytes of 10 healthy controls and two persons homozygous for the GR-9beta polymorphism, in which the expression of two GC-sensitive genes, GC-induced leucine zipper and IL-2, was measured., Results: Persons carrying the GR-9beta haplotype without 22/23EK (n = 53) revealed no significant differences in their body mass index, waist to hip ratio, fat spectrum, and insulin sensitivity or in their cortisol response to dexamethasone and levels of C-reactive protein, compared with noncarriers (n = 113). Ex vivo, GC-induced up-regulation of GC-induced leucine zipper mRNA via transactivation did not significantly differ in GR-9beta homozygotes, whereas the down-regulation of IL-2 expression via transrepression was decreased., Conclusion: Persons carrying the GR-9beta haplotype seem to have a decreased GC transrepression with normal transactivation.

Context: The clinical presentation of abnormalities in glucocorticoid (GC) sensitivity is diverse, and therefore it is difficult to diagnose this condition., Objective and Design: The objective of the study was to develop strategies for the characterization of GC sensitivity disorders., Setting: The study was conducted in an outpatient clinic., Patients: Nine patients with GC sensitivity disorders participated., Interventions: Sequence analysis of the GC receptor (GR), determination of GR number per cell, GR ligand-binding affinity, and GR splice regulation were performed in freshly prepared peripheral blood mononuclear lymphocytes and Epstein-Barr virus-transformed lymphoblasts. Cellular GC sensitivity was determined ex vivo by measuring the effect of dexamethasone on GC-induced leucine-zipper and IL-2 mRNA levels and on cell proliferation., Results: Differences in GR number per cell, GR affinity, GR splice variants, and effects on transactivation or transrepression of GC-sensitive genes were observed between patients and controls. Epstein-Barr virus transformation of lymphoblasts had no influence on GR affinity but increased the GR number 5-fold in healthy controls. In patients diagnosed as cortisol resistant, however, GR number after transformation was increased significantly less than 5-fold, whereas a higher GR number was observed in a patient suspected of cortisol hypersensitivity., Conclusion: This study illustrates several strategies to define abnormalities in GC sensitivity by describing nine patients with affected GC sensitivity, all with a unique clinical course and background.

In recent years enormous progress in determining the sequence of the human genome has led to a rapid development of research into polymorphisms in genes involved in complex diseases. It is clear, however, that there are important limitations in many of these association studies. Problems with reliable and reproducible phenotyping, the number of individuals studied, racial heterogeneity, population stratification (founder effect), functionality and multiple testing often mean that studies are not reproducible. In this review we describe a number of the limitations related to this type of research; from both our own experience with studies on polymorphisms in the glucocorticoid receptor gene, and shortcomings and solutions from the literature.

Context: Interindividual variation in glucocorticoid (GC)-sensitivity can be partly explained by polymorphisms in the GC receptor (GR) gene. The ER22/23EK and N363S polymorphisms have been described to be associated with lower and higher GC sensitivity, respectively., Objective and Design: We examined the basis of this altered GC sensitivity by expressing GR(N363S) and GR(ER22/23EK) in COS-1 cells and investigating their transactivating and transrepressing capacities using a GC response element-luciferase reporter and a p65-activated nuclear factor kappaB-luciferase reporter, respectively. Furthermore, we evaluated the transactivating and transrepressing capacities of the GR in peripheral blood mononuclear lymphocytes of homozygous and heterozygous carriers of these polymorphisms by determining the maximum effect of dexamethasone on transactivation of the GC-induced leucine-zipper and transinhibition of the IL-2 gene by means of real-time RT-PCR., Results: The effects of the polymorphisms in the GR gene previously observed in population studies were also detected at the level of gene expression. The ER22/23EK polymorphism resulted in a significant reduction of transactivating capacity, in both transfection experiments (-14 +/- 5%, P < 0.05) and peripheral blood mononuclear lymphocytes of carriers of this polymorphism (homozygous: -48 +/- 6%, P < 0.01, n = 1; heterozygous: -21 +/- 4%, P = 0.08, n = 3). The N363S polymorphism, associated with increased GC sensitivity, resulted in a significantly increased transactivating capacity, both in vitro (8 +/- 3%; P < 0.02) and ex vivo (homozygous: 204 +/- 19%, P < 0.0001, n = 1; heterozygous: 124 +/- 8%, P = 0.05, n = 3). Neither the ER22/23EK nor the N363S polymorphism seemed to influence the transrepressing capacity of the GR., Conclusion: The presence of these and other GC sensitivity-modulating polymorphisms may have consequences for the use of GCs in a clinical setting.

One of the most intriguing polymorphisms in the GR [glucocorticoid (GC) receptor] gene is in codons 22 and 23 [GAGAGG(GluArg) --> GAAAAG (GluLys)]. This polymorphism is associated with a reduced GC sensitivity, a better metabolic and cardiovascular health profile, and an increased survival rate. Recently, Yudt and Cidlowski reported that two different methionine codons in the GR mRNA may be used as initiation codon: AUG-1 and AUG-27, resulting in two isoforms, the GR-A and the GR-B proteins, respectively. They also showed that the GR-B protein had a stronger transactivating effect in transient transfection experiments. In this study, we elucidated the molecular basis for the reduced GC sensitivity by investigating the influence of the ER22/23EK polymorphism on synthesis of GR-A and GR-B by expressing them independently from constructs with and without the polymorphic site. Binding studies with [(3)H]-dexamethasone and transactivation studies showed that, when the ER22/23EK polymorphism is present, approximately 15% more GR-A protein was expressed, whereas total GR levels (GR-A + GR-B) were not affected. These results show that the transcriptional activity in GR(ER22/23EK) carriers is decreased because more of the less transcriptionally active GR-A isoform is formed. This is probably caused by altered secondary mRNA structure.