An in vitro bioassay to determine individual sensitivity to glucocorticoids: induction of FKBP51 mRNA in peripheral blood mononuclear cells

Differential expression of genes regulated by the glucocorticoid receptor pathway in patients with pulmonary tuberculosis

AIMS

Previous studies in TB patients showed an immuno-endocrine imbalance characterized by a disease-severity associated increase in plasma levels of proinflammatory cytokines and glucocorticoids (GCs). To analyze the potential immunomodulatory effect of circulating GCs over peripheral blood mononuclear cells (PBMC) from TB patients, we investigated the expression of positively (anti-inflammatory-related genes ANXA1; FKBP51; GILZ, NFKBIA, and NFKBIB) and negatively (inflammatory genes: IL-6, IL-1β, and IFN-γ) Glucocorticoids Receptors (GR)-regulated genes. Plasma concentrations of cytokines and hormones, together with specific lymphoproliferation were also assessed.

MATERIALS AND METHODS

Gene expression was quantified by RT-qPCR, specific lymphoproliferation by ³H-thymidine incorporation, whereas plasma cytokines and hormones levels by ELISA.

KEY FINDINGS

Transcripts of ANXA1, GILZ, NFKBIB, and NFKBIA appeared significantly increased in patients, whereas FKBP51, IL-6, IL-1β, and NF-κB remained unchanged. Upon analyzing according to disease severity, mRNA levels for ANXA1 and NFKBIB were even higher in moderate and severe patients. GILZ was increased in moderate cases, with NFKBIA and IL-1 β being higher in severe ones, who also displayed increased GRβ transcripts. TB patients had reduced plasma DHEA concentrations together with increased pro and anti-inflammatory cytokines (IFN-γ, IL-6, and IL-10) cortisol and cortisol/DHEA ratio, more evident in progressive cases, in whom their PBMC also showed a decreased mycobacterial-driven proliferation. The cortisol/DHEA ratio and GRα expression were positively correlated with GR-regulated genes mainly in moderate patients.

SIGNIFICANCE

The increased expression of cortisol-regulated anti-inflammatory genes in TB patients-PBMC, predominantly in progressive disease, seems compatible with a relatively insufficient attempt to downregulate the accompanying inflammation.

Association between ACTH stimulation test results and clinical signs in dogs with hyperadrenocorticism treated with trilostane

Trilostane is the recommended medical treatment for dogs with hyperadrenocorticicm (HAC). The objective of this study was to investigate the association between ACTH stimulation test (ACTHST) results, and relevant clinical signs, in dogs treated with trilostane. A disease-specific questionnaire was developed, which included the owner's assessment of polydipsia, polyuria, polyphagia, panting, and satisfaction with the treatment, based on a 5-response category rating scale. Forty-nine dogs with HAC were prospectively enrolled. Dogs were grouped according to their recheck appointment (first recheck, 710 days after commencement of treatment or change of trilostane dose; second recheck, 4 weeks after the first recheck; third recheck, performed at 3-6 months intervals once the dog was well controlled). At the recheck appointment, the owner's questionnaire responses were recorded, and an ACTHST was performed, along with urine specific gravity measurement. Linear mixed effects models were used to assess differences among the three recheck time points and to test possible associations between ACTHST results and clinical signs. Significant differences between rechecks were present for stimulated cortisol (first to third recheck, P < 0.001; second to third recheck, P < 0.01), polydipsia (first to second recheck, P = 0.001), polyuria (first to second recheck, P < 0.001; first to third recheck, P = 0.001), and owner satisfaction (first to second recheck, P < 0.001; first to third recheck, P < 0.001). Backward stepwise variable elimination did not identify any significant associations between ACTHST results and clinical signs. Therefore, clinical signs of HAC were not predicted based on the ACTHST results.

Antibody Response to Canine Parvovirus Vaccination in Dogs with Hyperadrenocorticism Treated with Trilostane

It is unknown how dogs with hyperadrenocorticism (HAC) respond to vaccination. This study measured antibodies against canine parvovirus (CPV) in dogs with HAC treated with trilostane before and after CPV vaccination, and compared the immune response to that from healthy dogs. Eleven dogs with HAC, and healthy age-matched control dogs (n = 31) received a modified-live CPV vaccine. Antibodies were determined on days 0, 7, and 28 by hemagglutination inhibition. Univariate analysis was used to compare the immune response of dogs with HAC and healthy dogs. Pre-vaccination antibodies (≥10) were detected in 100% of dogs with HAC (11/11; 95% CI: 70.0–100) and in 93.5% of healthy dogs (29/31; 95% CI: 78.3–99.2). No ≥4-fold increase in antibody titer was observed in dogs with HAC while in 22.6% of healthy dogs, a ≥4-fold titer increase was observed (7/31; 95% CI: 11.1–40.1). Mild vaccine-associated adverse events (VAAEs) were detected in 54.5% of dogs with HAC (6/11; 95% CI: 28.0–78.8) and in 29.0% of healthy dogs (9/31; 95% CI: 15.9–46.8). There was neither a significant difference in presence of pre-vaccination antibodies (p = 1.000), or response to vaccination (p = 0.161), nor in the occurrence of VAAEs (p = 0.158). Immune function of dogs with HAC treated with trilostane seems comparable to that of healthy dogs.

Expression of corticosteroid hormone receptors, prereceptors, and molecular chaperones in hypothalamic-pituitary-adrenal axis and adipose tissue after the administration of growth promoters in veal calves

The action of glucocorticoids on target tissues is regulated by the glucocorticoid and mineralocorticoid receptors (codified by the NR3C1 and NR3C2 gene, respectively). Moreover, the prereceptor system, represented by the hydroxysteroid 11-beta dehydrogenases (HSD11Bs), catalyzes the interconversion from active glucocorticoids into inactive compounds. This study aimed to determine whether the expression of the prereceptor system, the corticosteroid receptors, and the molecules regulating their intracellular trafficking (FKBP prolyl isomerase 4 and FKBP prolyl isomerase 5) could be regulated in the hypothalamic-pituitary-adrenal axis and in different type of adipose tissue of calves by the administration of dexamethasone in combination with estradiol or prednisolone. Research about the glucocorticoid effects on bovine target tissues may allow development of new diagnostic methods that use potential molecular biomarkers of glucocorticoid treatment. The administration of dexamethasone in combination with estradiol increased the gene expression of HSD11B1 (P < 0.01), HSD11B2 (P < 0.05), NR3C1 (P < 0.01), and NR3C2 (P < 0.01) in the adrenal glands; NR3C2 in the intramuscular adipose tissue (P < 0.01), and HSD11B1 in the subcutaneous adipose tissue (P < 0.01). Prednisolone administration increased the gene expression of HSD11B1 (P < 0.01), NR3C1 (P < 0.05), and NR3C2 (P < 0.05) in the adrenal glands and HSD11B1 (P < 0.01) in the subcutaneous adipose tissue. Interestingly, most of the examined tissues/organs showed a significant variation of FKBP5 gene expression after the administration of dexamethasone in combination with estradiol. So, these changes suggest that the FKBP5 gene expression could be a possible biomarker of the illegal dexamethasone administration in calves.

Role of FKBP51 in the modulation of the expression of the corticosteroid receptors in bovine thymus following glucocorticoid administration

The aim of this work was to study the transcriptional effects of glucocorticoids on corticosteroid hormone receptors, prereceptors (11β-hydroxysteroid dehydrogenase 1 and 2, 11β-HSD1 and 2), and chaperones molecules regulating intracellular trafficking of the receptors (FKBP51 and FKBP52) in thymus of veal calves. Moreover, the expression of FKBP51 and FKBP52 gene were investigated in beef cattle thymus. In the cervical thymus of veal calves, dexamethasone administration in combination with estradiol decreased FKBP51 expression (P < 0.01). The same treatment increased mineralocorticoid receptor (MR) (P < 0.01) and 11β-HSD1 expression (P < 0.05) compared to control group in the cervical thymus of veal calves. The thoracic thymus of veal calves treated with dexamethasone and estradiol showed a decrease of FKBP51 (P < 0.05), FKBP52 (P < 0.05), glucocorticoid receptor (P < 0.05), and MR expression (P < 0.05) compared to control group in the thoracic thymus of veal calves. The gene expression of FKBP51 decreased both in cervical (P < 0.01) and thoracic thymus (P < 0.01) of beef cattle treated with dexamethasone and estradiol. In addition, also prednisolone administration reduced FKBP51 expression in the cervical thymus (P < 0.01) and in the thoracic thymus of beef cattle (P < 0.01). The gene expression of FKBP52 increased only in the cervical thymus following dexamethasone administration (P < 0.01). The decrease of FKBP51 gene expression in thymus could be a possible biomarker of illicit dexamethasone administration in bovine husbandry. Moreover, so far, an effective biomarker of prednisolone administration is not identified. In this context, the decrease of FKBP51 gene expression in thymus of beef cattle following prednisolone administration could play an important role in the indirect identification of animals illegally treated with prednisolone.

Integrated transcriptome and methylome analysis in youth at high risk for bipolar disorder: a preliminary analysis

First-degree relatives of patients with bipolar disorder (BD), particularly their offspring, have a higher risk of developing BD and other mental illnesses than the general population. However, the biological mechanisms underlying this increased risk are still unknown, particularly because most of the studies so far have been conducted in chronically ill adults and not in unaffected youth at high risk. In this preliminary study we analyzed genome-wide expression and methylation levels in peripheral blood mononuclear cells from children and adolescents from three matched groups: BD patients, unaffected offspring of bipolar parents (high risk) and controls (low risk). By integrating gene expression and DNA methylation and comparing the lists of differentially expressed genes and differentially methylated probes between groups, we were able to identify 43 risk genes that discriminate patients and high-risk youth from controls. Pathway analysis showed an enrichment of the glucocorticoid receptor (GR) pathway with the genes MED1, HSPA1L, GTF2A1 and TAF15, which might underlie the previously reported role of stress response in the risk for BD in vulnerable populations. Cell-based assays indicate a GR hyporesponsiveness in cells from adult BD patients compared to controls and suggest that these GR-related genes can be modulated by DNA methylation, which poses the theoretical possibility of manipulating their expression as a means to counteract the familial risk presented by those subjects. Although preliminary, our results suggest the utility of peripheral measures in the identification of biomarkers of risk in high-risk populations and further emphasize the potential role of stress and DNA methylation in the risk for BD in youth.

Examining FKBP5 mRNA expression in human iPSC-derived neural cells

In peripheral blood leukocytes, FKBP5 mRNA expression is upregulated following glucocorticoid receptor activation. The single nucleotide polymorphism rs1360780 in FKBP5 is associated with psychiatric illness and has functional molecular effects. However, examination of FKBP5 regulation has largely been limited to peripheral cells, which may not reflect regulation in neural cells. We used 27 human induced pluripotent stem cell lines (iPSCs) derived from 20 subjects to examine FKBP5 mRNA expression following GR activation. Following differentiation into forebrain-lineage neural cultures, cells were exposed to 1μM dexamethasone and mRNA expression of FKBP5 and NR3C1 analyzed. Results from the iPSC-derived neural cells were compared with those from 15 donor matched fibroblast lines. Following dexamethasone treatment, there was a 670% increase in FKBP5 expression in fibroblasts, mimicking findings in peripheral blood-derived cells, but only a 23% increase in iPSC-derived neural cultures. FKBP5 rs1360780 genotype did not affect the induction of FKBP5 mRNA in either fibroblasts or neural cells. These results suggest that iPSC-derived forebrain-lineage neurons may not be an optimal neural cell type in which to examine relationships between GR activation, FKBP5 expression, and genetic variation in human subjects. Further, FKBP5 induction following GR activation may differ between cell types derived from the same individual.

FKBP5 polymorphism is associated with insulin resistance in children and adolescents with obesity

OBJECTIVE

Since metabolic syndrome shares several clinical features with hypercortisolism, it was hypothesised that genes altering individual glucocorticoid (GC) sensitivity might be implicated in pathogenesis of obesity and its adverse outcomes. FKBP5 gene encodes a chaperon protein in the GC receptor (GR) complex, which modulates steroid action upon target genes. Its functional variant, rs1360780, may enhance FKBP5 gene transcription, affect GR signalling and thereby influence the hypothalamo-pituitary-adrenal axis. We investigated the association of rs1360780 with obesity and metabolic characteristics in 250 obese children and adolescents (mean age 12.3±3.6years, BMI ≥95th percentile).

METHODS

Anthropometric measurements, body composition, biochemical and hormonal results were analysed. Genotyping of rs1360780 was compared with 568 lean controls.

RESULTS

Impaired fasting glucose was present in 8.8%, glucose intolerance in 10.4%, diabetes in 2.8% and dyslipidemia in 28.8% obese individuals. Hypertension was diagnosed in 34 out of 143 patients. No difference was found in FKBP5 polymorphism distribution between subjects with obesity and controls (p>0.05). Stratification by rs1360780 revealed no differences in body mass and composition. However, carriers of the minor allele displayed enhanced insulin resistance (p=0.009) and elevated serum triglyceride (p=0.006), whereas cholesterol, HbA1c, and oral glucose challenge results were similar for all genotypes. Morning ACTH and cortisol did not differ but evening cortisol was higher in minor allele carriers (p=0.039), although this association was lost in logistic regression analysis.

CONCLUSION

This study does not support the association of FKBP5 with obesity but demonstrates plausible implication of its variant in susceptibility to obesity-related insulin resistance and hypertriglyceridemia.

Hypothalamic-pituitary-adrenal axis dysfunction and illness progression in bipolar disorder

BACKGROUND

Impaired stress resilience and a dysfunctional hypothalamic-pituitary-adrenal (HPA) axis are suggested to play key roles in the pathophysiology of illness progression in bipolar disorder (BD), but the mechanisms leading to this dysfunction have never been elucidated. This study aimed to examine HPA axis activity and underlying molecular mechanisms in patients with BD and unaffected siblings of BD patients.

METHODS

Twenty-four euthymic patients with BD, 18 siblings of BD patients, and 26 healthy controls were recruited for this study. All subjects underwent a dexamethasone suppression test followed by analyses associated with the HPA axis and the glucocorticoid receptor (GR).

RESULTS

Patients with BD, particularly those at a late stage of illness, presented increased salivary post-dexamethasone cortisol levels when compared to controls (p = 0.015). Accordingly, these patients presented reduced ex vivo GR responsiveness (p = 0.008) and increased basal protein levels of FK506-binding protein 51 (FKBP51, p = 0.012), a co-chaperone known to desensitize GR, in peripheral blood mononuclear cells. Moreover, BD patients presented increased methylation at the FK506-binding protein 5 (FKBP5) gene. BD siblings presented significantly lower FKBP51 protein levels than BD patients, even though no differences were found in FKBP5 basal mRNA levels.

CONCLUSIONS

Our data suggest that the epigenetic modulation of the FKBP5 gene, along with increased FKBP51 levels, is associated with the GR hyporesponsiveness seen in BD patients. Our findings are consistent with the notion that unaffected first-degree relatives of BD patients share biological factors that influence the disorder, and that such changes are more pronounced in the late stages of the illness.

FKBP5 expression in human adipose tissue increases following dexamethasone exposure and is associated with insulin resistance

OBJECTIVE

To study effects of dexamethasone on gene expression in human adipose tissue aiming to identify potential novel mechanisms for glucocorticoid-induced insulin resistance.

MATERIALS/METHODS

Subcutaneous and omental adipose tissue, obtained from non-diabetic donors (10 M/15 F; age: 28-60 years; BMI: 20.7-30.6 kg/m²), was incubated with or without dexamethasone (0.003-3 μmol/L) for 24 h. Gene expression was assessed by microarray and real time-PCR and protein expression by immunoblotting.

RESULTS

FKBP5 (FK506-binding protein 5) and CNR1 (cannabinoid receptor 1) were the most responsive genes to dexamethasone in both subcutaneous and omental adipose tissue (~7-fold). Dexamethasone increased FKBP5 gene and protein expression in a dose-dependent manner in both depots. The gene product, FKBP51 protein, was 10-fold higher in the omental than in the subcutaneous depot, whereas the mRNA levels were similar. Higher FKBP5 gene expression in omental adipose tissue was associated with reduced insulin effects on glucose uptake in both depots. Furthermore, FKBP5 gene expression in subcutaneous adipose tissue was positively correlated with serum insulin, HOMA-IR and subcutaneous adipocyte diameter and negatively with plasma HDL-cholesterol. FKBP5 SNPs were found to be associated with type 2 diabetes and diabetes-related phenotypes in large population-based samples.

CONCLUSIONS

Dexamethasone exposure promotes expression of FKBP5 in adipose tissue, a gene that may be implicated in glucocorticoid-induced insulin resistance.

Corticosteroid receptor expression and in vivo glucocorticoid sensitivity in multiple sclerosis

To estimate the efficiency of glucocorticoid signaling in multiple sclerosis in vivo, we measured mRNA expression of glucocorticoid receptor (GR), mineralocorticoid receptor (MR) and four genes regulated by GR and implicated in immune function, in whole blood. GR expression and MR expression were significantly lower in 52 patients than in 18 controls. In contrast, expression of GR regulated genes was increased (significantly for glucocorticoid induced leucine zipper, GILZ), especially in mildly impaired patients. Reduced GR expression appears to be compensated, either by hyperactive hypothalamo-pituitary-adrenal axis or by intracellular adaptations.

Biomarkers can predict potential clinical responders to DIMS0150 a toll-like receptor 9 agonist in ulcerative colitis patients

BACKGROUND

Glucocorticoids (GCS) remain one of the mainstay treatments in the management of ulcerative colitis (UC) but up to a third of patients will ultimately fail to respond and progress to a more severe and difficult to manage disease state. Previous clinical studies suggest that the Toll-Like Receptor 9 (TLR9) agonist DIMS0150 not only induces production of key anti-inflammatory cytokines as IL-10 but interestingly also enhances steroid sensitivity in steroid refractory UC patients. We investigated, in the context of a clinical study, whether a pre-selection of steroid response genes could identify steroid refractory UC subjects most likely to respond to DIMS0150 treatment.

METHODS

In a non-interventional pilot study, blood from steroid refractory UC patients and healthy volunteers was taken and thirty-four previously described steroid response genes were analysed by real time PCR analysis. To establish clinical utility of the identified biomarkers, a placebo controlled, randomized, double blinded study in active steroid dependent and steroid resistant UC patients on concomitant steroid therapies was used (EudraCT number: 2006-001846-15).

RESULTS

We identified three potential biomarkers CD163, TSP-1 and IL-1RII whose response to steroids was significantly enhanced when DIMS0150 was applied. Thirty-four subjects were randomized to receive a single rectal administration of placebo or 30 mg of DIMS0150. Blood derived PBMCs were obtained prior to dosing and assayed for evidence of a steroid enhancing effect following steroid incubation in the presence of DIMS0150. Comparison to established steroid sensitivity marker IL-6 confirmed that clinical responders are steroid refractory UC patients. Upon study completion and un-blinding, the biomarker assay correctly predicted a clinical response in over 90% of the patients.

CONCLUSION

Using specific steroid response biomarkers, GCS refractory UC patients most likely to benefit from DIMS0150 treatment could be identified and illustrates the usefulness of a personalized treatment approach.

Genetic variation in FKBP5 associated with the extent of stress hormone dysregulation in major depression

The FK506 binding protein 51 or FKBP5 has been implicated in the regulation of glucocorticoid receptor (GR) sensitivity, and genetic variants in this gene have been associated with mood and anxiety disorders. GR resistance and associated stress hormone dysregulation are among the most robust biological findings in major depression, the extent of which may be moderated by FKBP5 polymorphisms. FKBP5 mRNA expression in peripheral blood cells (baseline and following in vivo GR stimulation with 1.5 mg dexamethasone p.o.) was analyzed together with plasma cortisol, ACTH, dexamethasone levels and the FKBP5 polymorphism rs1360780 in 68 depressed patients and 87 healthy controls. We observed a significant (P = 0.02) interaction between disease status and FKBP5 risk allele carrier status (minor allele T) on GR-stimulated FKBP5 mRNA expression. Patients carrying the risk T allele, but not the CC genotype, showed a reduced induction of FKBP5 mRNA. This FKBP5 polymorphism by disease status interaction was paralleled by the extent of plasma cortisol and ACTH suppression following dexamethasone administration, with a reduced suppression only observed in depressed patients carrying the T allele. Only depressed patients carrying the FKBP5 rs1360780 risk allele showed significant GR resistance compared with healthy controls, as measured by dexamethasone-induced FKBP5 mRNA induction in peripheral blood cells and suppression of plasma cortisol and ACTH concentrations. This finding suggests that endocrine alterations in depressed patients are determined by genetic variants and may allow identification of specific subgroups.

Regulation of mRNA expression encoding chaperone and co-chaperone proteins of the glucocorticoid receptor in peripheral blood: association with depressive symptoms during pregnancy

BACKGROUND

Major depressive disorder during pregnancy associates with potentially detrimental consequences for mother and child. The current study examined peripheral blood gene expression as a potential biomarker for prenatal depressive symptoms.

METHOD

Maternal RNA from whole blood, plasma and the Beck Depression Inventory were collected longitudinally from preconception through the third trimester of pregnancy in 106 women with a lifetime history of mood or anxiety disorders. The expression of 16 genes in whole blood involved in glucorticoid receptor (GR) signaling was assessed using real-time polymerase chain reaction. In parallel, plasma concentrations of progesterone, estradiol and cortisol were measured. Finally, we assessed ex vivo GR sensitivity in peripheral blood cells from a subset of 29 women.

RESULTS

mRNA expression of a number of GR-complex regulating genes was up-regulated over pregnancy. Women with depressive symptoms showed significantly smaller increases in mRNA expression of four of these genes - FKBP5, BAG1, NCOA1 and PPID. Ex vivo stimulation assays showed that GR sensitivity diminished with progression of pregnancy and increasing maternal depressive symptoms. Plasma concentrations of gonadal steroids and cortisol did not differ over pregnancy between women with and without clinically relevant depressive symptoms.

CONCLUSIONS

The presence of prenatal depressive symptoms appears to be associated with altered regulation of GR sensitivity. Peripheral expression of GR co-chaperone genes may serve as a biomarker for risk of developing depressive symptoms during pregnancy. The presence of such biomarkers, if confirmed, could be utilized in treatment planning for women with a psychiatric history.

Glucocorticoid resistance in Crohn's disease and ulcerative colitis: an association study investigating GR and FKBP5 gene polymorphisms

The aim of this study is to investigate the role of single-nucleotide polymorphisms (SNPs) of the glucocorticoid receptor (GR) and of the related co-chaperone FKBP5 genes in the development of glucocorticoid (GC) resistance in Crohn's disease (CD) and ulcerative colitis (UC) patients. We have developed a high-resolution DNA melting method that allows simultaneous identification of GR (BclI, N363S and ER22/23EK) and FKBP5 (rs3800373, rs1360780 and rs4713916) polymorphisms. Genotype frequencies were determined in 100 consecutive CD and 100 UC patients under GCs therapy (50 responders and 50 resisters). The variation of FKBP5 polymorphism rs4713916 (G/A), in the putative promoter region of FKBP5, is significantly associated with resistance to GC treatment in CD (responder=17% versus resister=35%; P=0.0043). No significant differences were found in UC patients. If these preliminary findings will be confirmed, the combination of GR and FKBP5 mutational analyses could help to identify subgroups of CD patients with higher chances to benefit from GC treatment.

Using polymorphisms in FKBP5 to define biologically distinct subtypes of posttraumatic stress disorder: evidence from endocrine and gene expression studies

CONTEXT

Polymorphisms in the gene encoding the glucocorticoid receptor (GR) regulating co-chaperone FKBP5 have been shown to alter GR sensitivity and are associated with an increased risk to develop posttraumatic stress disorder (PTSD).

OBJECTIVE

To investigate interactions of the FKBP5 single-nucleotide polymorphism rs9296158 and PTSD symptoms on baseline cortisol level, low-dose dexamethasone suppression, and whole-blood gene expression.

DESIGN

Association of FKBP5 genotypes and PTSD symptoms with endocrine measures and genome-wide expression profiles.

SETTING

Waiting rooms of general medical and gynecological clinics of an urban hospital at Emory University.

PARTICIPANTS

The 211 participants were primarily African American (90.05%) and of low socioeconomic status and had high rates of trauma and PTSD.

MAIN OUTCOME MEASURES

Baseline and post-dexamethasone suppression cortisol measures and gene expression levels.

RESULTS

In our endocrine study, we found that only risk allele A carriers of rs9296158 showed GR supersensitivity with PTSD; in contrast, baseline cortisol levels were decreased in PTSD only in patients with the GG genotype. Expression of 183 transcripts was significantly correlated with PTSD symptoms after multiple testing corrections. When adding FKBP5 genotype and its interaction with PTSD symptoms, expression levels of an additional 32 genes were significantly regulated by the interaction term. Within these 32 genes, previously reported PTSD candidates were identified, including FKBP5 and the IL18 and STAT pathways. Significant overrepresentation of steroid hormone transcription factor binding sites within these 32 transcripts was observed, highlighting the fact that the earlier-described genotype and PTSD-dependent differences in GR sensitivity could drive the observed gene expression pattern. Results were validated by reverse transcriptase-polymerase chain reaction and replicated in an independent sample (N = 98).

CONCLUSIONS

These data suggest that the inheritance of GR sensitivity-moderating FKBP5 polymorphisms can determine specific types of hypothalamic-pituitary-adrenal axis dysfunction within PTSD, which are also reflected in gene-expression changes of a subset of GR-responsive genes. Thus, these findings indicate that functional variants in FKBP5 are associated with biologically distinct subtypes of PTSD.

Steroid up-regulation of FKBP51 and its role in hormone signaling

FK506 binding protein 51 (FKBP51, FKBP5) functions as a co-chaperone for androgen, glucocorticoid, mineralocorticoid and progesterone receptors. The FKBP51 can act as an important determinant of the responses to steroids, especially to glucocorticoids in stress and mood disorders and androgens in prostate cancer, raising medical and pharmacological interests in the protein and its gene. Recent studies have revealed the molecular mechanisms by which the androgens and the glucocorticoids via their nuclear receptors elicit the robust up-regulation of the FKBP51 gene. Several polymorphisms in the FKBP51 gene have been associated with the mood disorders and differences in glucocorticoid sensitivity. The polymorphisms may contribute to the steroid up-regulation of the FKBP51 and thus influence the regulatory loops in steroid signaling.

Dexamethasone-induced FKBP51 expression in peripheral blood mononuclear cells could play a role in predicting the response of asthmatics to treatment with corticosteroids

BACKGROUND

Corticosteroids (CSs) are the preferred anti-inflammatory therapy for the treatment of asthma, but the responses of asthmatics to CSs are known to vary. It has thus become important to discover reliable markers in predicting responses to CSs.

METHODS

We performed time-series microarrays using a murine model of asthma after a single dose of dexamethasone, based on the assumption that the gene showing a greater change in response to CSs can also be a potential marker for that finding. We then evaluated the clinical meaning of the gene discovered in the microarray experiments.

RESULTS

We found that the expression of FK506 binding protein 51 gene (FKBP51) in lung tissue markedly increased after dexamethasone treatment in a murine model of asthma. We then measured dexamethasone-induced FKBP51 expression in peripheral blood mononuclear cells (PBMCs) in asthmatics. Dexamethasone-induced FKBP51 expression in PBMCs was significantly higher in severe asthmatics compared with mild-to-moderate asthmatics treated with inhaled CSs. In addition, we found that dexamethasone-induced FKBP51 expression in PBMCs was inversely correlated with improvement in lung function after treatment with orally administered prednisolone in six steroid-naive asthmatics.

CONCLUSION

Dexamethasone-induced FKBP51 expression in PBMCs may be a reliable and practical biomarker in predicting the response to CSs in asthmatics.

Glucocorticoid receptor activates poised FKBP51 locus through long-distance interactions

Recent studies have identified FKBP51 (FK506-binding protein 51) as a sensitive biomarker of corticosteroid responsiveness in vivo. In this work, we have elucidated the molecular mechanisms underlying the induction of FKBP51 by the glucocorticoid receptor (GR) in human A549 lung cancer cells showing robust accumulation of FKBP51 mRNA in response to dexamethasone exposure. Our quantitative chromatin immunoprecipitation scans and enhancer activity analyses indicate that activation of the FKBP51 locus by glucocorticoids in vivo is triggered by the loading of GR to enhancers at about 34 kb 5' and about 87 kb 3' of the transcription start site. Interestingly, the region encompassing these enhancers is bordered by CCCTC-binding factor- and cohesin-binding sites. Dexamethasone treatment also decreased the histone density at several regions of the gene, which was paralleled with the occupancy of SWI/SNF chromatin remodeling complexes within the locus. Moreover, silencing of BRM subunit of the SWI/SNF complex blunted the glucocorticoid induction of the locus. The proximal promoter region along with the major intronic enhancer at approximately 87 kb, at which the GR binding peaked, had elevated levels of histone 3 acetylation and H3K4 trimethylation, whereas H3K36 trimethylation more generally marked the gene body and reflected the occupancy of RNA polymerase II. The occurrence of these active chromatin marks within the FKBP51 locus before glucocorticoid exposure suggests that it is poised for transcription in A549 cells. Taken together, these results indicate that the holo-GR is capable of activating transcription and evoking changes in chromatin structure through distant-acting enhancers.

Pharmacological strategies for improving the efficacy and therapeutic ratio of glucocorticoids in inflammatory lung diseases

Glucocorticoids are widely used to treat various inflammatory lung diseases. Acting via the glucocorticoid receptor (GR), they exert clinical effects predominantly by modulating gene transcription. This may be to either induce (transactivate) or repress (transrepress) gene transcription. However, certain individuals, including those who smoke, have certain asthma phenotypes, chronic obstructive pulmonary disease (COPD) or some interstitial diseases may respond poorly to the beneficial effects of glucocorticoids. In these cases, high dose, often oral or parental, glucocorticoids are typically prescribed. This generally leads to adverse effects that compromise clinical utility. There is, therefore, a need to enhance the clinical efficacy of glucocorticoids while minimizing adverse effects. In this context, a long-acting beta(2)-adrenoceptor agonist (LABA) can enhance the clinical efficacy of an inhaled corticosteroid (ICS) in asthma and COPD. Furthermore, LABAs can augment glucocorticoid-dependent gene expression and this action may account for some of the benefits of LABA/ICS combination therapies when compared to ICS given as a monotherapy. In addition to metabolic genes and other adverse effects that are induced by glucocorticoids, there are many other glucocorticoid-inducible genes that have significant anti-inflammatory potential. We therefore advocate a move away from the search for ligands of GR that dissociate transactivation from transrepression. Instead, we submit that ligands should be functionally screened by virtue of their ability to induce or repress biologically-relevant genes in target tissues. In this review, we discuss pharmacological methods by which selective GR modulators and "add-on" therapies may be exploited to improve the clinical efficacy of glucocorticoids while reducing potential adverse effects.

Urinary corticoid: creatinine ratios in dogs with pituitary-dependent hypercortisolism during trilostane treatment

BACKGROUND

The adrenocorticotropic hormone (ACTH) stimulation test is used to evaluate trilostane treatment in dogs with hypercortisolism.

HYPOTHESIS

The urinary corticoid : creatinine ratio (UCCR) is a good alternative to the ACTH stimulation test to determine optimal trilostane dose.

ANIMALS

Eighteen dogs with pituitary-dependent hypercortisolism.

METHODS

In this prospective study, the dose of trilostane was judged to be optimal on the basis of resolution of clinical signs of hypercortisolism and results of an ACTH stimulation test. The owners collected urine for determination of UCCR at 2-week intervals for at least 8 weeks after achieving the optimal trilostane dose.

RESULTS

The UCCRs were significantly higher before treatment (11.5-202.0 x 10(-6); median, 42.0 x 10(-6)) than at rechecks 2 months after optimal dosing, but they did not decrease below the upper limit of the reference range in the majority of dogs. The UCCRs of 11 dogs that initially were dosed insufficiently (range, 7.5-79.0 x 10(-6); median, 31.0 x 10(-6)) did not differ significantly from UCCRs when the dosage was optimal (8.2-72.0 x 10(-6); median, 33.0 x 10(-6)). Post-ACTH cortisol concentrations did not correlate significantly with UCCRs at rechecks during trilostane treatment. Long-term follow-up indicated that the decrease in UCCR below the upper limit of the reference was associated with hypocortisolism.

CONCLUSION AND CLINICAL IMPORTANCE

The UCCR cannot be used as an alternative to the ACTH stimulation test to determine the optimal dose of trilostane, but might be helpful in detecting dogs at risk for developing hypocortisolism during trilostane treatment.

Effects of trilostane on the pituitary-adrenocortical and renin-aldosterone axis in dogs with pituitary-dependent hypercortisolism

The medical records of 63 dogs with pituitary-dependent hypercortisolism (PDH) before and during treatment with trilostane were reviewed retrospectively. The correct trilostane dosage in dogs with PDH was based on the resolution of clinical signs and the results of an adrenocorticotropic hormone (ACTH) stimulation test. The mean (+/-SD) dose rate of trilostane to achieve good clinical control was 2.8+/-1.0mg/kg bodyweight. Trilostane treatment resulted in a significant decline in basal plasma cortisol concentrations. The median plasma ACTH concentration (39 pmol/L, range 7-132 pmol/L; n=60) at the optimal trilostane dosage time was significantly higher (P<0.001) than before treatment (13 pmol/L, range 2-102 pmol/L). These values did not overlap with plasma ACTH concentrations (range 212-307 pmol/L) of five PDH dogs with trilostane-induced hypocortisolism. The median cortisol/ACTH ratio in well-controlled dogs (0.23, range 0.03-2.5; n=46) was significantly lower (P<0.001) than before treatment (2.59, range 0.27-13.25). Trilostane treatment resulted in an insignificant decrease in plasma aldosterone concentration (PAC), but the median plasma renin activity (PRA) at the time the trilostane dosage was considered optimal (265 fmol/L/s, range 70-3280 fmol/L/s; n=18) was significantly higher (P<0.001) than prior to treatment (115 fmol/L/s, range 15-1330 fmol/L/s). Similarly, the median PAC/PRA ratio during trilostane treatment (0.16, range 0.003-0.92; n=17) was significantly lower (P<0.001) than before treatment (median 0.44, range 0.04-1.33). Trilostane affected both the hypothalamic-pituitary-adrenocortical and the renin-aldosterone axes. The results also suggested that basal plasma ACTH concentration may be used to detect trilostane overdosage.

Gene expression profiling of leukemic cells and primary thymocytes predicts a signature for apoptotic sensitivity to glucocorticoids

Background

Glucocorticoids (GC's) play an integral role in treatment strategies designed to combat various forms of hematological malignancies. GCs also are powerful inhibitors of the immune system, through regulation of appropriate cytokines and by causing apoptosis of immature thymocytes. By activating the glucocorticoid receptor (GR), GCs evoke apoptosis through transcriptional regulation of a complex, interactive gene network over a period of time preceding activation of the apoptotic enzymes. In this study we used microarray technology to determine whether several disparate types of hematologic cells, all sensitive to GC-evoked apoptosis, would identify a common set of regulated genes. We compared gene expression signatures after treatment with two potent synthetic GCs, dexamethasone (Dex) and cortivazol (CVZ) using a panel of hematologic cells. Pediatric CD4+/CD8+ T-cell leukemia was represented by 3 CEM clones: two sensitive, CEM-C7–14 and CEM-C1–6, and one resistant, CEM-C1–15, to Dex. CEM-C1–15 was also tested when rendered GC-sensitive by several treatments. GC-sensitive pediatric B-cell leukemia was represented by the SUP-B15 line and adult B-cell leukemia by RS4;11 cells. Kasumi-1 cells gave an example of the rare Dex-sensitive acute myeloblastic leukemia (AML). To test the generality of the correlations in malignant cell gene sets, we compared with GC effects on mouse non-transformed thymocytes.

Results

We identified a set of genes regulated by GCs in all GC-sensitive malignant cells. A portion of these were also regulated in the thymocytes. Because we knew that the highly Dex-resistant CEM-C1–15 cells could be killed by CVZ, we tested these cells with the latter steroid and again found that many of the same genes were now regulated as in the inherently GC-sensitive cells. The same result was obtained when we converted the Dex-resistant clone to Dex-sensitive by treatment with forskolin (FSK), to activate the adenyl cyclase/protein kinase A pathway (PKA).

Conclusion

Our results have identified small sets of genes that correlate with GC-sensitivity in cells from several hematologic malignancies. Some of these are also regulated in normal mouse thymocytes.

Glucocorticoids modulate NF-kappaB-dependent gene expression by up-regulating FKBP51 expression in Newcastle disease virus-infected chickens

FK506-binding protein 51(FKBP51, coded by FKBP5) is a co-chaperone molecule that interacts with the chaperone HSP90 and the glucocorticoid receptor (GR) in an inactive GR complex. It is a negative regulator of glucocorticoid action and is replaced by the positive regulator, FK506-binding protein 52 (FKBP52, coded by FKBP4) when hormone binds to GR, which renders the GR complex active. In this study, we found that the expression of FKBP51 mRNA in 12 organs of Newcastle disease virus (NDV)-infected chickens was robustly induced. The level of corticosterone in NDV-infected chickens was also elevated, approximately 2- to 6.5-fold in the organs compared to non-infected control chickens. The induction of FKBP51 mRNA expression was reproduced by dexamethasone treatment, indicating a role for glucocorticoids in the systemic induction of FKBP51 mRNA expression. In chicken UMNSAH/DF-1 cells, nuclear factor kappaB (NF-kappaB) was activated in an FKBP51-dependent manner. Regulation of the three NF-kappaB-dependent, anti-apoptotic genes, bcl-2, bcl-x and bfl-1/A1 was investigated in UMNSAH/DF-1 cells. Dexamethasone treatment of UMNSAH/DF-1 cells resulted in up-regulation of bcl-2, and down-regulation of bcl-x and bfl-1/A1. Expression of FKBP51 also resulted in down-regulation of bfl-1/A1, but had no effect on bcl-2 and bcl-x, suggesting the involvement of glucocorticoid-FKBP51-NF-kappaB signaling in the regulation of expression of bfl-1/A1 in UMNSAH/DF-1 cells. We observed organ-specific up- or down-regulation of expression of, bcl-2, bcl-x and bfl-1/A1 in NDV-infected and dexamethasone-treated chickens. Differential regulation of bfl-1/A1, bcl-2 and bcl-x upon NDV-infection and dexamethasone treatment suggests that additional factors are involved in the regulation of these genes. These results suggest that systemic elevation of FKBP51 in NDV-infected chickens activates NF-kappaB, which cooperates with other factors to regulate the expression of NF-kappaB-dependent genes.

Genome-wide profiling identifies epithelial cell genes associated with asthma and with treatment response to corticosteroids

Airway inflammation and epithelial remodeling are two key features of asthma. IL-13 and other cytokines produced during T helper type 2 cell-driven allergic inflammation contribute to airway epithelial goblet cell metaplasia and may alter epithelial-mesenchymal signaling, leading to increased subepithelial fibrosis or hyperplasia of smooth muscle. The beneficial effects of corticosteroids in asthma could relate to their ability to directly or indirectly decrease epithelial cell activation by inflammatory cells and cytokines. To identify markers of epithelial cell dysfunction and the effects of corticosteroids on epithelial cells in asthma, we studied airway epithelial cells collected from asthmatic subjects enrolled in a randomized controlled trial of inhaled corticosteroids, from healthy subjects and from smokers (disease control). By using gene expression microarrays, we found that chloride channel, calcium-activated, family member 1 (CLCA1), periostin, and serine peptidase inhibitor, clade B (ovalbumin), member 2 (serpinB2) were up-regulated in asthma but not in smokers. Corticosteroid treatment down-regulated expression of these three genes and markedly up-regulated expression of FK506-binding protein 51 (FKBP51). Whereas high baseline expression of CLCA1, periostin, and serpinB2 was associated with a good clinical response to corticosteroids, high expression of FKBP51 was associated with a poor response. By using airway epithelial cells in culture, we found that IL-13 increased expression of CLCA1, periostin, and serpinB2, an effect that was suppressed by corticosteroids. Corticosteroids also induced expression of FKBP51. Taken together, our findings show that airway epithelial cells in asthma have a distinct activation profile and identify direct and cell-autonomous effects of corticosteroid treatment on airway epithelial cells that relate to treatment responses and can now be the focus of specific mechanistic studies.

Staphylococcus aureus-superantigen decreases FKBP51 mRNA expression and cell-response to suppressive efficacy of a glucocorticoid in human peripheral blood mononuclear cells: possible implication of mitogen-activated protein kinase pathways

Glucocorticoids are commonly used for treatment of chronic inflammatory diseases, while a number of patients show insensitivity to glucocorticoid treatment. The molecular basis of these individual differences in glucocorticoid pharmacodynamics has little been taken into account. Here we focus on the implication of Staphylococcus aureus-producing superantigen, such as toxic shock syndrome toxin-1 (TSST-1), in the glucocorticoid sensitivity of human peripheral blood mononuclear cells and cell-response to glucocorticoid to produce a transcript for FK506-binding protein (FKBP51). Peripheral blood mononuclear cell-sensitivity to glucocorticoid was assessed by a cell proliferation test. FKBP51mRNA expressions were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR). We also compared concentrations of various cytokines produced in culture supernatant between concanavalin A- and TSST-1-stimulated peripheral blood mononuclear cells using a cytometric beads array. Mitogen-activated protein kinase (MAPK) phosphorylation activity in peripheral blood mononuclear cells stimulated with concanavalin A and TSST-1 was analyzed by a cell-based ELISA. Prednisolone markedly inhibited concanavalin A-induced peripheral blood mononuclear cell proliferation, but they scarcely inhibited TSST-1-induced peripheral blood mononuclear cell proliferation. The mean (S.D.) of immunosuppressant concentrations that would give 50% (IC(50)) values for prednisolone in concanavalin A-stimulated peripheral blood mononuclear cells was 52.6 (54.2) ng/ml, which was significantly lower than that in TSST-1-stimulated peripheral blood mononuclear cells, i.e., 574.2 (817.0) ng/ml (P<0.001). TSST-1-stimulated peripheral blood mononuclear cells for 48 h attenuated prednisolone-induced FKBP51mRNA expressions concomitantly with decreased sensitivity to the anti-proliferative effects of prednisolone. Concentrations of interleukin-2 (IL-2) produced from TSST-1-stimulated peripheral blood mononuclear cells were significantly higher than that from peripheral blood mononuclear cells stimulated with concanavalin A (P<0.0001). Both concanavalin A and TSST-1 enhanced the phosphorylation of extracellular signal-regulated kinase (ERK) and p38, whereas the level of c-jun terminal kinase (JNK) phosphorylation was only increased by TSST-1-stimulation in peripheral blood mononuclear cells. Furthermore, the decreased FKBP51mRNA by TSST-1was found to be recovered by JNK and mitogen-activated protein kinase (MEK)/ERK inhibitors. Our data suggest that TSST-1 reduces activity of glucocorticoid in peripheral blood mononuclear cells by JNK activation and subsequent production of IL-2. Therefore, JNK might be an attractive target for overcoming glucocorticoid insensitivity induced by TSST-1 in peripheral blood mononuclear cells.

Rho family Guanine nucleotide exchange factor Brx couples extracellular signals to the glucocorticoid signaling system

Glucocorticoids regulate many crucial biologic functions through their cytoplasmic/nuclear glucocorticoid receptors (GR). Excess, deficiency, or alteration in tissue sensitivity to glucocorticoids has been associated with major causes of human morbidity and mortality. Brx, a cytoplasmic Rho family guanine nucleotide exchange factor, binds to and influences the activity of several nuclear hormone receptors. We examined the functional and molecular interactions between GR and Brx. The glucocorticoid sensitivity of lymphocytes obtained from mice haplo-insufficient for Brx was significantly decreased. Conversely, GR-mediated transcriptional activity of a glucocorticoid response element (GRE)-mediated glucocorticoid-responsive promoter was enhanced by Brx in a guanine nucleotide exchange factor domain-dependent fashion. Brx interacted with GR, forming a ternary complex with RhoA. In a chromatin immunoprecipitation assay, Brx and RhoA were co-precipitated with GREs only in the presence of ligand-activated GR. Extracellularly administered lysophosphatidic acid, which activates its signaling cascade through a specific membrane GTP-binding protein (G-protein)-coupled receptor in a G-protein alpha(13)-, Brx-, and RhoA-dependent fashion, enhanced GR transcriptional activity, whereas depletion of endogenous Brx attenuated this effect. These findings suggest that glucocorticoid signaling and, hence, the tissue sensitivity to glucocorticoids, may be coupled to extracellular signals via Brx and small G-proteins. Nuclear Brx might act as a local GRE-GR-transcriptosome activator by mediating the effect of small G-proteins on glucocorticoid-regulated genes.

Identification of glucocorticoid-response genes in children with acute lymphoblastic leukemia

The ability of glucocorticoids (GCs) to kill lymphoid cells led to their inclusion in essentially all chemotherapy protocols for lymphoid malignancies, particularly childhood acute lymphoblastic leukemia (ALL). GCs mediate apoptosis via their cognate receptor and subsequent alterations in gene expression. Previous investigations, including expression profiling studies with subgenome microarrays in model systems, have led to a number of attractive, but conflicting, hypotheses that have never been tested in a clinical setting. Here, we present a comparative whole-genome expression profiling approach using lymphoblasts (purified at 3 time points) from 13 GC-sensitive children undergoing therapy for ALL. For comparisons, expression profiles were generated from an adult patient with ALL, peripheral blood lymphocytes from GC-exposed healthy donors, GC-sensitive and -resistant ALL cell lines, and mouse thymocytes treated with GCs in vivo and in vitro. This generated an essentially complete list of GC-regulated candidate genes in clinical settings and experimental systems, allowing immediate analysis of any gene for its potential significance to GC-induced apoptosis. Our analysis argued against most of the model-based hypotheses and instead identified a small number of novel candidate genes, including PFKFB2, a key regulator of glucose metabolism; ZBTB16, a putative transcription factor; and SNF1LK, a protein kinase implicated in cell-cycle regulation.