Glucocorticoid Receptor Sensitivity Research Articles

Complement C5a Receptor Signaling Alters Stress Responsiveness and Modulates Microglia Following Chronic Stress Exposure

BackgroundAccumulating evidence underscores the pivotal role of heightened inflammation in the pathophysiology of stress-related diseases, but the underlying mechanisms remain elusive. The complement system, a key effector of the innate immune system, produces the C5–cleaved activation product C5a upon activation, initiating inflammatory responses through the canonical C5a receptor 1 (C5aR1). While C5aR1 is expressed in stress-responsive brain regions, its role in stress responsiveness remains unknown. MethodsTo investigate C5a-C5aR1 signaling in stress responses, mice underwent acute and chronic stress paradigms. Circulating C5a levels and messenger RNA expression of C5aR1 in the hippocampus and adrenal gland were measured. C5aR1-deficient mice were used to elucidate the effects of disrupted C5a-C5aR1 signaling across behavioral, hormonal, metabolic, and inflammation parameters. ResultsChronic restraint stress elevated circulating C5a levels while reducing C5aR1 messenger RNA expression in the hippocampus and adrenal gland. Notably, the absence of C5aR1 signaling enhanced adrenal sensitivity to adrenocorticotropic hormone, concurrently reducing pituitary adrenocorticotropic hormone production and enhancing the response to acute stress. C5aR1-deficient mice exhibited attenuated reductions in locomotor activity and body weight under chronic stress. Additionally, these mice displayed increased glucocorticoid receptor sensitivity and disrupted glucose and insulin homeostasis. Chronic stress induced an increase in C5aR1-expressing microglia in the hippocampus, a response mitigated in C5aR1-deficient mice. ConclusionsC5a-C5aR1 signaling emerges as a key metabolic regulator during stress, suggesting that complement activation and dysfunctional C5aR1 signaling may contribute to neuroinflammatory phenotypes in stress-related disorders. The results advocate for further exploration of complement C5aR1 as a potential therapeutic target for stress-related conditions.

Integrating Proteomics and Functional Genomics to Identify Targets for Improving Glucocorticoid-Based Treatment of B-Lymphoblastic Leukemia

Glucocorticoids are a critical component of successful combination chemotherapy regimens for B-lymphoblastic leukemia (B-ALL). Despite advances in immunotherapies, glucocorticoid-based chemotherapy continues to be the essential frontline treatment of patients with B-ALL. This approach has led to high cure rates but at the risk of both acute, potentially life-threatening complications and chronic toxicities. Additionally, glucocorticoids remain ineffective for some patients with B-ALL, which predicts poor outcomes. To achieve better outcomes and reduce the toxicity of treatment, we take a functional genomics approach to understand how glucocorticoids induce cell death and identify strategies to make them more effective. Glucocorticoids work through the glucocorticoid receptor (GR), a ligand-activated transcription factor, to induce cell death in B-ALL. By integrating gene expression and RNA interference screening, we have identified both effector genes (genes whose regulation by glucocorticoids contributes to B-ALL cell death) and sources of resistance that can be targeted to improve treatment (Kruth et al Blood 2017). This identified the network of BCL-2 family proteins (e.g., BCL2, BCL2L11, BMF), whose regulation contributes to apoptosis in B-ALL. Surprisingly, it also showed that suppression of B-cell development genes (e.g., EBF1, PAX5, IL7R) contributes to B-ALL cell death. However, only a fraction of the genes that affect the glucocorticoid sensitivity of B-ALL are effector genes. We therefore sought to identify functional interaction partners of GR, defined as proteins that physically interact with GR and influence glucocorticoid sensitivity. To identify proteins that physically interact with GR, we used proximity labeling. We fused an ascorbate peroxidase domain (APEX2) to the N-terminus of GR and expressed it REH cells, a B-ALL cell line that does not express GR protein. After verifying that APEX2-GR restored glucocorticoid sensitivity in the REH cells, we performed proximity labeling in the presence and absence of dexamethasone. After optimizing these reactions, cells were lysed and labeled proteins were isolated using magnetic streptavidin beads and identified by mass spectrometry. We were able to detect more than 4,000 proteins that interact with GR, including hundreds that are enriched upon addition of dexamethasone. To identify functional interaction, we intersected the proteins enriched upon addition of dexamethasone with proteins shown by us to modulate glucocorticoid sensitivity in B-ALL (Kruth et al Blood 2017). Supporting our working model, we found functional interaction partners that are involved in B-cell development and apoptosis. We found that GR interacts with EBF1 and MEF2C, B-cell development transcription factors that restrain glucocorticoid-induced cell death. This indicates that GR activity and glucocorticoid sensitivity is directly blunted by B-cell development, and further supports the model that glucocorticoids restrain B-cell development. The mechanism of how these interactions influence glucocorticoid sensitivity will guide rational targeting to improve treatment of B-ALL both in general and in different B-ALL subtypes. Additionally, the mitochondrial voltage dependent anion channel 2 (VDAC2) also interacts with GR in a dexamethasone-dependent manner and is integral to glucocorticoid-induced cell death. VDAC2 is important for nucleating and perhaps triggering pore formation through BAK and BAX. How GR influences this activity is not known but suggests a non-genomic role of GR in glucocorticoid-induced cell death. In summary, integration of functional genomics and proteomics provides rich data sets that will help understand the mechanism of glucocorticoid-induced B-ALL cell death. Targeting of non-canonical (B-cell development) and non-genomic (VDAC2) functions of GR will allow for optimization of glucocorticoid-based chemotherapy regimens.

OR11-03 A Novel Mutation In The Ligand-binding Domain Of The NR3C1 Gene Associated With Fluctuating Resistance To Glucocorticoids

Abstract Disclosure: M. Laulhé: None. E. Kuhn: None. J. Bouligand: None. L. Amazit: None. J. Perrot: None. P. Kamenicky: None. M. Lombes: None. J. Fagart: None. S. Viengchareun: None. L. Martinerie: None. Introduction: Constitutive glucocorticoid resistance is associated with mutations in the NR3C1 gene, encoding the Glucocorticoid Receptor (GR). We identified a novel heterozygous point mutation causing fluctuating resistance to glucocorticoid depending on ligand concentrations. Initially, the propositus, a 45-year-old man, was diagnosed with a right adrenal incidentaloma and an ACTH-independent biological hypercortisolism. Shortly after adrenal surgery, plasma cortisol increased again (612 nmol/L) associated with inadequate ACTH levels (122 pg/mL) without any evidence of pituitary adenoma or ectopic ACTH-secreting tumor, suggesting a glucocorticoid resistance syndrome. Methods: We sequenced NR3C1 gene and performed in vitro analysis to assess contribution of this variant to the patient’s phenotype and how it affects biological activity of GR. Results: Exon sequencing of the NR3C1 gene identified a novel missense variant located on exon 5 (NM_000176.3, c.1706 G>A) resulting in substitution of arginine to glutamine at amino acid 569 (GR R569Q) in the Ligand-Binding Domain (LBD) of GR. We characterized transcriptional activity of GR R569Q in HEK 293T cells transiently co-transfected with either GR WT or GR R569Q, together with a luciferase reporter gene construct placed under control of a promoter containing two glucocorticoid responsive elements. We observed a decreased transcriptional activity of GR R569Q (EC50 4.55 nM [3.8;5.3]) compared to GR WT (EC50 0.19 nM [0.15; 0.24]), in response to dexamethasone. Interestingly, GR R569Q exerted a dominant negative effect on GR WT, with a decrease in transcriptional activity of 80% when stimulated with 1 nM dexamethasone (2-way ANOVA test, P<0.0001), which was blunted when stimulated with a 100-fold higher concentration of dexamethasone. As the variant is located within the second nuclear localization signal, we studied nuclear translocation in response to 1 nM cortisol for 1 h. As expected, nuclear-cytoplasmic ratio was lower in patients’ fibroblasts (2.3 ± 0.14 vs 3.0 ± 0.98, ANOVA 2-Way, P < 0.0001) compared with control fibroblasts, as quantified by automated high-throughput microscopy. Three-dimensional modeling revealed that arginine substitution leads to loss of a hydrogen bond stabilizing the LBD structure. This may result in a lower ligand affinity that can be bypassed by high concentrations of agonist. We are currently testing receptor affinity and reversibility of phenotype after hydrogen bond restoration by directed mutagenesis (c.1705 C>A, p.Q569K). Conclusion: Overall, we identified a novel variant of the NR3C1 gene associated with fluctuating GR sensitivity depending on ligand concentration. This finding may provide new insights into mechanisms involved in GR sensitivity. Presentation: Friday, June 16, 2023

Methylation and expression of glucocorticoid receptor exon-1 variants and FKBP5 in teenage suicide-completers

A dysregulated hypothalamic-pituitary-adrenal (HPA) axis has repeatedly been demonstrated to play a fundamental role in psychiatric disorders and suicide, yet the mechanisms underlying this dysregulation are not clear. Decreased expression of the glucocorticoid receptor (GR) gene, which is also susceptible to epigenetic modulation, is a strong indicator of impaired HPA axis control. In the context of teenage suicide-completers, we have systematically analyzed the 5’UTR of the GR gene to determine the expression levels of all GR exon-1 transcript variants and their epigenetic state. We also measured the expression and the epigenetic state of the FK506-binding protein 51 (FKBP5/FKBP51), an important modulator of GR activity. Furthermore, steady-state DNA methylation levels depend upon the interplay between enzymes that promote DNA methylation and demethylation activities, thus we analyzed DNA methyltransferases (DNMTs), ten-eleven translocation enzymes (TETs), and growth arrest- and DNA-damage-inducible proteins (GADD45). Focusing on both the prefrontal cortex (PFC) and hippocampus, our results show decreased expression in specific GR exon-1 variants and a strong correlation of DNA methylation changes with gene expression in the PFC. FKBP5 expression is also increased in both areas suggesting a decreased GR sensitivity to cortisol binding. We also identified aberrant expression of DNA methylating and demethylating enzymes in both brain regions. These findings enhance our understanding of the complex transcriptional regulation of GR, providing evidence of epigenetically mediated reprogramming of the GR gene, which could lead to possible epigenetic influences that result in lasting modifications underlying an individual’s overall HPA axis response and resilience to stress.

FKBP5 intron 7 methylation is associated with higher anxiety proneness and smaller right thalamus volume in adolescents.

Dysregulation of stress response systems may mediate the detrimental effects of childhood trauma (CT) on mental health. FKBP5 regulates glucocorticoid receptor sensitivity and exerts pleiotropic effects on intracellular signaling, neurobiology and behavior. We investigated whether CT, alone and in combination with rs1360780 genotype, is associated with altered FKBP5 methylation and whether CT-associated methylation profiles are associated with anxiety proneness (AP) and structural brain volumes. Ninety-four adolescents completed the Childhood Trauma Questionnaire, and a composite AP score was generated from the Childhood Anxiety Sensitivity Index and the State-Trait Anxiety Inventory-Trait measure. Mean methylation values for 12 regulatory regions and 25 individual CpG sites were determined using high-accuracy measurement via targeted bisulfite sequencing. FKBP5 rs1360780 genotype and structural MRI data were available for a subset of participants (n = 71 and n = 75, respectively). Regression models revealed an inverse association between methylation of three intron 7 CpG sites (35558438, 35558566 and 35558710) and right thalamus volume. CpG35558438 methylation was positively associated with AP scores. Our data indicate that an intron 7 methylation profile, consistent with lower FKBP5 expression and elevated high sensitivity glucocorticoid receptor levels, is associated with higher AP and smaller right thalamus volume. Research into the mechanisms underlying the intron 7 methylation-thalamus volume relationship, and whether it confers increased risk for long-term psychopathology by altering the regulatory threshold of stress responding, is required.

Accelerated forgetting of a trauma-like event in healthy men and women after a single dose of hydrocortisone

Posttraumatic stress disorder (PTSD) is characterised by dysregulated hypothalamic-pituitary-adrenal axis activity and altered glucocorticoid receptor sensitivity. Early treatment with glucocorticoids may reduce PTSD risk, although the effect of such treatment on the aetiologically critical step of traumatic-memory-formation remains unclear. Here we examine the effects of exogenous cortisol (hydrocortisone) in a preclinical model of PTSD, using a factorial (Drug × Sex), randomised-controlled, double-blind design. Healthy men and women (n = 120) were randomised to receive 30 mg oral hydrocortisone or matched placebo immediately after watching a stressful film. Effects on film-related intrusions were assessed acutely in the lab, and ecologically using daily memory diaries for one week. We found that participants receiving hydrocortisone showed a faster reduction in daily intrusion frequency. Voluntary memory was assessed once, at the end of the week, but was unaffected by hydrocortisone. Exploratory analyses indicated sex-dependent associations between intrusions and baseline estradiol and progesterone levels. In men receiving hydrocortisone, higher baseline estradiol levels were associated with fewer intrusions, whereas women exhibited the opposite pattern. By contrast, progesterone levels were positively associated with intrusions only in men treated with hydrocortisone. The findings suggest that hydrocortisone promotes an accelerated degradation of sensory-perceptual representations underlying traumatic intrusive memories. In addition, while sex alone was not an important moderator, the combination of sex and sex-hormone levels (especially estradiol) influenced hydrocortisone’s effects on involuntary aversive memories. Future well-powered experimental studies may provide a basis for a precision-psychiatry approach to optimising early post-traumatic glucocorticoid treatments that target intrusive memories, based on individual endocrinological profiles.

Epigenetic mechanisms and stress coping in mood disorders

IntroductionExperimental data from both clinical and preclinical studies have unequivocally shown positive correlations between stress and depression, stress, depression and epigenetic changes.ObjectivesThe aim of this research is to analyze clinical trials on coping mechanisms and their interaction with epigenetic mechanisms in patients with mood disorders. Generally, we studied the interaction between these two mechanisms and its effects on the onset, recurrence and progression of these disorders.Methods109 articles were analyzed, of which 37 were considered relevant. 72 studies were excluded based on titles and abstracts. Regarding the coping mechanisms, 10 longitudinal and cross-sectional studies were selected. Longitudinal studies are defined here by a follow-up period longer than 6 months.ResultsThere is a consistent association in the literature between the degree of methylation of the NR3C1 gene, stress and affectivity disorders. The analyzed studies showed that methylation of the NR3C1 gene is associated with both stress and mood disorders. FKBP5 influences glucocorticoid receptor sensitivity and stress response. SLC6A4 gene methylation has been systematically associated with stress and affectivity disorders. Higher BDNF methylation has also been found in people who report high levels of stress at work. The data collected suggest that SKA2 methylation may serve as a biomarker for certain features of depression, such as suicidal ideation, and is not directly involved in the etiology of mood disorders.ConclusionsThe results suggest that environmental stress and adversity in early childhood may change biological systems through epigenetic mechanisms and have long-term consequences, increasing the risk for unfavorable prognosis of mood disorders.DisclosureNo significant relationships.

Higher glucocorticoid receptor sensitivity is associated with less favorable body composition in patients with obesity

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Tricyclic antidepressants target FKBP51 SUMOylation to restore glucocorticoid receptor activity.

FKBP51 is an important inhibitor of the glucocorticoid receptor (GR) signaling. High FKBP51 levels are associated to stress-related disorders, which are linked to GR resistance. SUMO conjugation to FKBP51 is necessary for FKBP51's inhibitory action on GR. The GR/FKBP51 pathway is target of antidepressant action. Thus we investigated if these drugs could inhibit FKBP51 SUMOylation and therefore restore GR activity. Screening cells using Ni2+ affinity and in vitro SUMOylation assays revealed that tricyclic antidepressants- particularly clomipramine- inhibited FKBP51 SUMOylation. Our data show that clomipramine binds to FKBP51 inhibiting its interaction with PIAS4 and therefore hindering its SUMOylation. The inhibition of FKBP51 SUMOylation decreased its binding to Hsp90 and GR facilitating FKBP52 recruitment, and enhancing GR activity. Reduction of PIAS4 expression in rat primary astrocytes impaired FKBP51 interaction with GR, while clomipramine could no longer exert its inhibitory action. This mechanism was verified in vivo in mice treated with clomipramine. These results describe the action of antidepressants as repressors of FKBP51 SUMOylation as a molecular switch for restoring GR sensitivity, thereby providing new potential routes of antidepressant intervention.

An Advanced Transcriptional Response to Corticosterone After Single Prolonged Stress in Male Rats.

Stress-related neuropsychiatric disorders are often accompanied by dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis. In patients suffering from post-traumatic stress disorder (PTSD), increased sensitivity of glucocorticoid negative feedback has regularly been observed. The single prolonged stress (SPS) paradigm was developed to model increased negative feedback and other aspects of PTSD in rats. In this study, we used a setup that precluded the evaluation of negative feedback but rather served to test the hypothesis of the enhanced glucocorticoid receptor (GR) signaling in higher brain areas. We injected corticosterone or vehicle 7 days after SPS and evaluated plasma corticosterone, as well as gene expression in the dorsal hippocampus and amygdala. We observed a strikingly rapid change in the expression of established GR target genes (t = 30 min) only in the SPS group on exogenous corticosterone injection. Our results extend the notion of increased GR sensitivity in PTSD to include transcriptional responses in the hippocampus.

Longitudinal CSF proteome profiling in mice to uncover the acute and sustained mechanisms of action of rapid acting antidepressant (2R,6R)-hydroxynorketamine (HNK)

Delayed onset of antidepressant action is a shortcoming in depression treatment. Ketamine and its metabolite (2R,6R)-hydroxynorketamine (HNK) have emerged as promising rapid-acting antidepressants. However, their mechanism of action remains unknown. In this study, we first described the anxious and depression-prone inbred mouse strain, DBA/2J, as an animal model to assess the antidepressant-like effects of ketamine and HNK in vivo. To decode the molecular mechanisms mediating HNK's rapid antidepressant effects, a longitudinal cerebrospinal fluid (CSF) proteome profiling of its acute and sustained effects was conducted using an unbiased, hypothesis-free mass spectrometry-based proteomics approach. A total of 387 proteins were identified, with a major implication of significantly differentially expressed proteins in the glucocorticoid receptor (GR) signaling pathway, providing evidence for a link between HNK and regulation of the stress hormone system. Mechanistically, we identified HNK to repress GR-mediated transcription and reduce hormonal sensitivity of GR in vitro. In addition, mammalian target of rapamycin (mTOR) and brain-derived neurotrophic factor (BDNF) were predicted to be important upstream regulators of HNK treatment. Our results contribute to precise understanding of the temporal dynamics and molecular targets underlying HNK's rapid antidepressant-like effects, which can be used as a benchmark for improved treatment strategies for depression in future.

Mineralocorticoid receptors dampen glucocorticoid receptor sensitivity to stress via regulation of FKBP5.

SUMMARYResponding to different dynamic levels of stress is critical for mammalian survival. Disruption of mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) signaling is proposed to underlie hypothalamic-pituitary-adrenal (HPA) axis dysregulation observed in stress-related psychiatric disorders. In this study, we show that FK506-binding protein 51 (FKBP5) plays a critical role in fine-tuning MR:GR balance in the hippocampus. Biotinylated-oligonucleotide immunoprecipitation in primary hippocampal neurons reveals that MR binding, rather than GR binding, to the Fkbp5 gene regulates FKBP5 expression during baseline activity of glucocorticoids. Notably, FKBP5 and MR exhibit similar hippocampal expression patterns in mice and humans, which are distinct from that of the GR. Pharmacological inhibition and region- and cell type-specific receptor deletion in mice further demonstrate that lack of MR decreases hippocampal Fkbp5 levels and dampens the stress-induced increase in glucocorticoid levels. Overall, our findings demonstrate that MR-dependent changes in baseline Fkbp5 expression modify GR sensitivity to glucocorticoids, providing insight into mechanisms of stress homeostasis.

Changes in glucocorticoid receptor sensitivity following long‐term ethanol self‐administration in male and female rhesus macaques

Stress can alter ethanol consumption and long-term use results in adaptation of the stress response, highlighting a bidirectional relationship that remains poorly understood. Non-human primates are an excellent model to investigate the interaction of stress and long-term ethanol use due to their similar neuroendocrine system to humans and propensity to chronically drink intoxicating amounts of alcohol. Here, circulating stress hormones (adrenocorticotropin hormone (ACTH) and cortisol) were measured in response to a low (17 mg/kg) and high (130 mg/kg) dose of dexamethasone, a potent glucocorticoid receptor (GR) agonist. The dexamethasone response was compared before (baseline) and after 7 months of daily 22 h/d ethanol self-administration in young adult male (n=6) and female (n=6) rhesus macaques. At both timepoints, the high dose dexamethasone challenge resulted in 90-100% suppression of both ACTH and cortisol with no difference between sexes. At baseline, low dose dexamethasone reduced both ACTH and cortisol, but to a lesser degree and with greater between-subject variability, 0 – 60%. Following seven-months of daily ethanol consumption (average intakes ranging from 0.6 – 4.0 g/kg/day) the response to low dose dexamethasone was greater. This effect was more robust in females compared to males. Additionally, the change in suppression between baseline and following long-term daily ethanol consumption correlated with daily intake, such that the magnitude of change over time was greater in heavier drinkers. Because stress increases reliance on putamen-dependent or habitual behavior and heavy ethanol drinking leads to excitatory-inhibitory neurotransmission imbalance within the putamen, we tested the hypothesis that long-term ethanol self-administration will alter striatal transmission via the GR. Therefore, we used whole cell patch clamp electrophysiology to investigate the effect of bath application of dexamethasone onto putamen medium spiny neurons (MSNs). Dexamethasone rapidly decreased the area and amplitude of spontaneous inhibitory postsynaptic currents among binge drinkers. These data show that acute dexamethasone, presumably via activation of the membrane bound GR, activated fewer GABAergic receptors among binge drinkers. These data highlight a unique role of the GR within the putamen that may mediate stress dependent changes contributing to addiction vulnerability, particularly among binge drinkers.

The co-chaperone Fkbp5 shapes the acute stress response in the paraventricular nucleus of the hypothalamus of male mice

Disturbed activation or regulation of the stress response through the hypothalamic-pituitary-adrenal (HPA) axis is a fundamental component of multiple stress-related diseases, including psychiatric, metabolic, and immune disorders. The FK506 binding protein 51 (FKBP5) is a negative regulator of the glucocorticoid receptor (GR), the main driver of HPA axis regulation, and FKBP5 polymorphisms have been repeatedly linked to stress-related disorders in humans. However, the specific role of Fkbp5 in the paraventricular nucleus of the hypothalamus (PVN) in shaping HPA axis (re)activity remains to be elucidated. We here demonstrate that the deletion of Fkbp5 in Sim1+ neurons dampens the acute stress response and increases GR sensitivity. In contrast, Fkbp5 overexpression in the PVN results in a chronic HPA axis over-activation, and a PVN-specific rescue of Fkbp5 expression in full Fkbp5 KO mice normalizes the HPA axis phenotype. Single-cell RNA sequencing revealed the cell-type-specific expression pattern of Fkbp5 in the PVN and showed that Fkbp5 expression is specifically upregulated in Crh+ neurons after stress. Finally, Crh-specific Fkbp5 overexpression alters Crh neuron activity, but only partially recapitulates the PVN-specific Fkbp5 overexpression phenotype. Together, the data establish the central and cell-type-specific importance of Fkbp5 in the PVN in shaping HPA axis regulation and the acute stress response.

Interaction of FKBP5 variant rs3800373 and city living alters the neural stress response in the anterior cingulate cortex

Psychosocial stress effects of urban living are associated with substantially increased risk for schizophrenia, mood and anxiety disorders, by altering stress-induced activity in the amygdala and pregenual anterior cingulate cortex (ACC). Genetic factors are likely to modulate the impact of city living on stress processing. Growing evidence suggests a key role of FKBP5, a co-chaperone regulating the glucocorticoid receptor sensitivity, in the etiology of stress-related disorders. Here we investigated the interaction of city living and genetic variation in FKBP5 (rs3800373) on neural activity in stress-sensitive brain systems. Functional magnetic resonance imaging was performed in 31 healthy young adults using the Montreal Imaging Stress Task. Subjects were divided into groups depending on the number of inhabitants of their current residency. There was a significant main effect of city living on neural activity in the amygdala-hippocampus complex, replicating prior findings. Moreover, we found an interaction between rs3800373 and city living modulating responses in the bilateral subgenual ACC and right pregenual ACC. Specifically, only city dwellers carrying the FKBP5 minor risk allele showed increased stress responses in the subgenual and pregenual ACC when compared to those living in small towns. A significant gene-environment interaction on neural stress responses in the amygdala or hippocampus was only found in FKBP5 major allele carriers. These results point to a potential role of the FKBP5 rs3800373 minor risk allele in predisposing those who live in bigger cities to changes of functional responsivity in the pre- and subgenual ACC, thereby increasing the risk for developing stress-related mental disorders.

Myelination defects in the medial prefrontal cortex of Fkbp5 knockout mice.

The hypothalamic-pituitary-adrenal (HPA) axis plays a principal role in stress response regulation and has been implicated in the etiology of stress-related disorders. The HPA axis regulates the normal synthesis and release of glucocorticoids; dysregulation of the HPA axis causes abnormal responses to stress. FK506-binding protein 5 (FKBP5), a co-chaperone of heat shock protein 90 in the glucocorticoid receptor (GR) molecular complex, is a key GR sensitivity regulator. FKBP5 single nucleotide polymorphisms are associated with dysregulated HPA axis and increased risk of stress-related disorders, including posttraumatic stress disorder (PTSD) and depression. In this study, we profiled the microRNAs (miRNAs) in the medial prefrontal cortex of Fkbp5 knockout (Fkbp5-/- ) mice and identified the target genes of differentially expressed miRNAs using sequence-based miRNA target prediction. Gene ontology analysis revealed that the differentially expressed miRNAs were involved in nervous system development, regulation of cell migration, and intracellular signal transduction. The validation of the expression of predicted target genes using quantitative polymerase chain reaction revealed that the expression of axon development-related genes, specifically actin-binding LIM protein 1 (Ablim1), lemur tyrosine kinase 2 (Lmtk2), kinesin family member 5c (Kif5c), neurofascin (Nfasc), and ephrin type-A receptor 4 (Epha4), was significantly decreased, while that of brain-derived neurotrophic factor (Bdnf) was significantly increased in the brain of Fkbp5-/- mice. These results suggest that axonal development-related genes can serve as potential targets in future studies focused on understanding the pathophysiology of PTSD.

Ex vivo glucocorticoid receptor-mediated IL-10 response predicts the course of depression severity

Directly measuring hypothalamic pituitary adrenal (HPA) axis function, an important player in affective disorders, is intensive and invasive. A crucial component of this system, the activity of the glucocorticoid receptor (GR), can be assessed ex vivo instead. Here, we investigated GR sensitivity in patients with major depressive disorder (MDD) to determine its predictive potential. Psychometric data and blood samples were collected from patients experiencing a major depressive episode (MDE, n = 87), healthy control subjects (n = 49), and patients with remitted MDD (n = 31) at baseline and (for patients) after median 20 days of follow-up after treatment as usual. Blood cells were stimulated ex vivo with lipopolysaccharide and the effect was suppressed by increasing dexamethasone (DEX) concentrations. The resultant cytokine secretion profile (for IL-6, IL-10, and TNF-α) was considered indicative of GR activity. Higher baseline scores of the Montgomery–Åsberg Depression Rating Scale (MADRS) were associated with a stronger decrease of logIC IL-6 (indicating an increase of GR sensitivity). Higher baseline logEC IL-10 (indicating a lower GR sensitivity) and a stronger reduction of logEC IL-10 (indicating a stronger increase in GR sensitivity) were associated with a stronger decrease in the MADRS score. Patients with remitted MDD showed higher logIC TNF-α values (indicating lower GR sensitivity) in comparison to patients with a current MDD at baseline and follow-up. Initially low GR sensitivity measured ex vivo in peripheral blood cells that increases over the course of treatment could serve as a predictive marker for stronger improvement in depression severity.

Роль гипоталамо-гипофизарно-адренокортикальной системы человека в адаптации к физическим нагрузкам

Regular physical activity, especially associated with the development of aerobic abilities, helps to improve the physical and mental health of a person. Increasing the level of fitness reduces the risk of overall mortality for both healthy people and people with chronic diseases. Exercise is accompanied by activation of the hypothalamic-pituitary-adrenocortical axis (HPA). The degree of its activation depends primarily on the intensity and duration of the load. Glucocorticoids of the adrenal glands which are hormones of the final link of the HPA, and their synthetic analogs can have a positive effect on the physical form of people. They adapt carbohydrate and fat metabolism to the energy needs of the body during exercise; have anti-inflammatory and immunosuppressive effects, protecting working muscles from damage. Adaptation to regular physical activity changes the reactivity of HPA most often in the direction of decreasing its susceptibility to negative feedback. It is also accompanied by changes in the sensitivity of tissues to glucocorticoids, which may be associated with the appearance of variations in the number and sensitivity of glucocorticoid receptors. The review describes the factors influencing the reaction of the HPA system in response to acute and chronic exercise, discusses the role of this system in adaptation of a person to physical activity. The great influence of individual characteristics of a person on the level of HPA reactivity during exercise is emphasized.

Anthropometrics and Metabolic Syndrome in Relation to Glucocorticoid Receptor Polymorphisms in Corticosteroid Users

Introduction: Corticosteroids are widely prescribed and their use has been linked to adverse cardiometabolic outcomes. A pivotal role in the action of corticosteroids is reserved for the glucocorticoid receptor (GR). Here, we assessed the relationship of glucocorticoid sensitivity-altering GR polymorphisms with anthropometrics and metabolic syndrome (MetS) in corticosteroid users. Methods: In this population-based cohort study (Lifelines), we genotyped 10,621 adult participants for GR hypersensitive (1/2 copies BclI and/or N363S) and GR resistant (1/2 copies ER22/23EK and/or 9β) variants. We assessed the relationship between functional GR polymorphisms with BMI, waist circumference (WC), and MetS in users of corticosteroids. Results: Overall corticosteroid use was associated with a significantly higher BMI and WC in GR wild-type (WT) users (BMI, +0.63 kg/m² [0.09–1.16], p = 0.022; WC, +2.03 cm [0.61–3.44], p = 0.005) and GR hypersensitive (BMI, +0.66 kg/m² [95% CI, 0.31–1.01]; WC, +2.06 cm [1.13–2.98], both p < 0.001) but not in GR resistant users. Significantly higher WC in GR resistant carriers was observed only for inhaled corticosteroid users. With respect to MetS, again only GR WT users (odds ratio [OR] 1.44 [1.07–1.94], p = 0.017) and GR hypersensitives (OR 1.23 [95% CI, 1.00–1.50], p = 0.046) were more likely to have MetS; even more pronounced in only inhaled corticosteroid users (GR WT users, OR 1.64 [1.06–2.55], p = 0.027; GR hypersensitive users, OR 1.43 [1.08–1.91], p = 0.013). Conclusions: Polymorphisms associated with increased GR sensitivity and WT GR are related to increased BMI, WC, and an increased MetS presence in corticosteroid users, especially of the inhaled types, when compared to nonusers. The adverse effects of corticosteroid use are less pronounced in users harboring GR resistant polymorphisms.

Moderate Aerobic Exercise Training Prevents the Augmented Hepatic Glucocorticoid Response Induced by High-Fat Diet in Mice.

Glucocorticoids (GCs) are critical regulators of energy balance. Their deregulation is associated with the development of obesity and metabolic syndrome. However, it is not understood if obesity alters the tissue glucocorticoid receptor (GR) response, and moreover whether a moderate aerobic exercise prevents the alteration in GR response induced by obesity. Methods: To evaluate the GR response in obese mice, we fed C57BL6J mice with a high-fat diet (HFD) for 12 weeks. Before mice were sacrificed, we injected them with dexamethasone. To assess the exercise role in GR response, we fed mice an HFD and subjected them to moderate aerobic exercise three times a week. Results: We found that mice fed a high-fat diet for 12 weeks developed hepatic GC hypersensitivity without changes in the gastrocnemius or epididymal fat GR response. Therefore, moderate aerobic exercise improved glucose tolerance, increased the corticosterone plasma levels, and prevented hepatic GR hypersensitivity with an increase in epididymal fat GR response. Conclusion: Collectively, our results suggest that mice with HFD-induced obesity develop hepatic GR sensitivity, which could enhance the metabolic effects of HFD in the liver. Moreover, exercise was found to be a feasible non-pharmacological strategy to prevent the deregulation of GR response in obesity.