Glucocorticoid receptor antagonist CORT113176 attenuates motor and neuropathological symptoms of Huntington's disease in R6/2 mice.

Huntington's Disease (HD) is a progressive neurodegenerative disease caused by a mutation in the huntingtin gene. The mutation leads to a toxic gain of function of the mutant huntingtin (mHtt) protein resulting in cellular malfunction, aberrant huntingtin aggregation and eventually neuronal cell death. Patients with HD show impaired motor functions and cognitive decline. Elevated levels of glucocorticoids have been found in HD patients and in HD mouse models, and there is a positive correlation between increased glucocorticoid levels and the progression of HD. Therefore, antagonism of the glucocorticoid receptor (GR) may be an interesting strategy for the treatment of HD. In this study, we evaluated the efficacy of the selective GR antagonist CORT113176 in the commonly used R6/2 mouse model. In male mice, CORT113176 treatment significantly delayed the loss of grip strength, the development of hindlimb clasping, gait abnormalities, and the occurrence of epileptic seizures. CORT113176 treatment delayed loss of DARPP-32 immunoreactivity in the dorsolateral striatum. It also restored HD-related parameters including astrocyte markers in both the dorsolateral striatum and the hippocampus, and microglia markers in the hippocampus. This suggests that CORT113176 has both cell-type and brain region-specific effects. CORT113176 delayed the formation of mHtt aggregates in the striatum and the hippocampus. In female mice, we did not observe major effects of CORT113176 treatment on HD-related symptoms, with the exception of the anti-epileptic effects. We conclude that CORT113176 effectively delays several key symptoms related to the HD phenotype in male R6/2 mice and believe that GR antagonism may be a possible treatment option.

Neuropsychiatric adverse effects of synthetic glucocorticoids: A systematic review and meta-analysis.

BACKGROUND: Synthetic glucocorticoids are widely used among patients suffering from a wide range of diseases. Glucocorticoids are very efficacious, but can be accompanied by neuropsychiatric adverse effects. This systematic review and meta-analysis assesses and quantifies the proportion of different neuropsychiatric adverse effects in patients using synthetic glucocorticoids. METHODS: Six electronic databases were searched to identify potentially relevant studies. Randomized controlled trials, cohort and cross-sectional studies assessing psychiatric side effects of glucocorticoids measured with validated questionnaires were eligible. Risk of bias was assessed with RoB 2, ROBINS-I, and AXIS appraisal tool. For proportions of neuropsychiatric outcomes, we pooled proportions, and when possible, differences in questionnaire scores between glucocorticoid users and non-users were expressed as standardized mean differences (SMD). Data were pooled in a random-effects logistic regression model. RESULTS: We included 49 studies with heterogeneity in study populations, type, dose, and duration of glucocorticoids. For glucocorticoid users, meta-analysis showed a proportion of 22% for depression (95%CI 14%-33%), 11% for mania (95%CI 2%-46%), 8% for anxiety (95%CI 2%-25%), 16% for delirium (95%CI 6%-36%), and 52% for behavioural changes (95%CI 42%-61%). Questionnaire scores for depression (SMD of 0.80 (95%CI 0.35-1.26)), and mania (0.78 (95%CI 0.14-1.42)) were higher than in controls, indicating more depressive and manic symptoms following glucocorticoid use. CONCLUSIONS: The heterogeneity of glucocorticoid use is reflected in the available studies. Despite this heterogeneity, the proportion of neuropsychiatric adverse effects in glucocorticoid users is high. The most substantial associations with glucocorticoid use were found for depression and mania. Upon starting glucocorticoid treatment, awareness of possible psychiatric side effects is essential. More structured studies on incidence and potential pathways of neuropsychiatric side effects of prescribed glucocorticoids are clearly needed.

Harnessing PROTAC technology to combat stress hormone receptor activation.

Counteracting the overactivation of glucocorticoid receptors (GR) is an important therapeutic goal in stress-related psychiatry and beyond. The only clinically approved GR antagonist lacks selectivity and induces unwanted side effects. To complement existing tools of small-molecule-based inhibitors, we present a highly potent, catalytically-driven GR degrader, KH-103, based on proteolysis-targeting chimera technology. This selective degrader enables immediate and reversible GR depletion that is independent of genetic manipulation and circumvents transcriptional adaptations to inhibition. KH-103 achieves passive inhibition, preventing agonistic induction of gene expression, and significantly averts the GR's genomic effects compared to two currently available inhibitors. Application in primary-neuron cultures revealed the dependency of a glucocorticoid-induced increase in spontaneous calcium activity on GR. Finally, we present a proof of concept for application in vivo. KH-103 opens opportunities for a more lucid interpretation of GR functions with translational potential.

The importance of the circadian trough in glucocorticoid signaling: a variation on B-flat.

Glucocorticoid hormones are essential for health, but overexposure may lead to many detrimental effects, including metabolic, psychiatric, and bone disease. These effects may not only be due to increased overall exposure to glucocorticoids, but also to elevated hormone levels at the time of the physiological circadian trough of glucocorticoid levels. The late Mary Dallman developed a model that allows the differentiation between the effects of overall 24-hour glucocorticoid overexposure and the effects of a lack of circadian rhythmicity. For this, she continuously treated rats with a low dose of corticosterone (or "B"), which leads to a constant hormone level, without 24-hour overexposure using subcutaneously implanted pellets. The data from this "B-flat" model suggest that even modest elevations of glucocorticoid signaling during the time of the normal circadian trough of hormone secretion are a substantial contributor to the negative effects of glucocorticoids on health.

Comparison of two corticosteroid regimens on brain volumetrics in patients with Duchenne muscular dystrophy.

OBJECTIVE: Duchenne muscular dystrophy (DMD) is a neuromuscular disorder in which many patients also have neurobehavioral problems. Corticosteroids, the primary pharmacological treatment for DMD, have been shown to affect brain morphology in other conditions, but data in DMD are lacking. This study aimed to investigate the impact of two corticosteroid regimens on brain volumetrics in DMD using magnetic resonance imaging (MRI). METHODS: In a cross-sectional, two-center study, T1-weighted MRI scans were obtained from three age-matched groups (9-18 years): DMD patients treated daily with deflazacort (DMDd, n = 20, scan site: Leuven), DMD patients treated intermittently with prednisone (DMDi, n = 20, scan site: Leiden), and healthy controls (n = 40, both scan sites). FSL was used to perform voxel-based morphometry analyses and to calculate intracranial, total brain, gray matter, white matter, and cerebrospinal fluid volumes. A MANCOVA was employed to compare global volumetrics between groups, with site as covariate. RESULTS: Both patient groups displayed regional differences in gray matter volumes compared to the control group. The DMDd group showed a wider extent of brain regions affected and a greater difference overall. This was substantiated by the global volume quantification: the DMDd group, but not the DMDi group, showed significant differences in gray matter, white matter, and cerebrospinal fluid volumes compared to the control group, after correction for intracranial volume. INTERPRETATION: Volumetric differences in the brain are considered part of the DMD phenotype. This study suggests an additional impact of corticosteroid treatment showing a contrast between pronounced alterations seen in patients receiving daily corticosteroid treatment and more subtle differences in those treated intermittently.

Temporal associations between salivary cortisol and emotions in clinically depressed individuals and matched controls: A dynamic time warp analysis.

Depression can be understood as a complex dynamic system where depressive symptoms interact with one another. Cortisol is suggested to play a major role in the pathophysiology of depression, but knowledge on the temporal interplay between cortisol and depressive symptoms is scarce. We aimed to analyze the temporal connectivity between salivary cortisol and momentary affective states in depressed individuals and controls. Thirty pair-matched depressed and non-depressed participants completed questionnaires on momentary positive (PA) and negative (NA) affect and collected saliva three times a day for 30 days. The association between cortisol and affect was analyzed by dynamic time warp (DTW) analyses. These analyses involved lag-1 backward to lag-1 forward undirected analyses and lag-0 and lag-1 forward directed analyses. Large inter- and intra-individual variability in the networks were found. At the group level, with undirected analysis PA and NA were connected in the networks in depressed individuals and in controls. Directed analyses indicated that increases in cortisol preceded specific NA items in controls, but tended to follow upon specific affect items increase in depressed individuals. To conclude, at group level, changes in cortisol levels in individuals diagnosed with a depression may be a result of changes in affect, rather than a cause.

Glucocorticoid receptor modulator CORT125385 alleviates diet-induced hepatosteatosis in male and female mice.

Non-alcoholic fatty liver disease (NAFLD) is a common condition that can progress to the more severe conditions like non-alcoholic steatohepatitis (NASH) for which limited effective therapeutic options are available. In this study, we set out to evaluate the novel glucocorticoid receptor modulator CORT125385, an analogue of the previously studied miricorilant but without mineralocorticoid receptor binding activity. Male and female mice that received high-fat diet and fructose water were treated with either vehicle, CORT125385 or mifepristone. We found that CORT125385 significantly lowered hepatic triglyceride levels in male mice, and hepatic triglyceride and cholesterol levels in female mice. Mifepristone treatment had no effect in male mice, but significantly lowered hepatic triglyceride and cholesterol levels in female mice. In reporter assays in vitro, CORT125385 showed weak partial agonism on the progesterone receptor (PR) at high doses, as well as PR antagonism at a potency 1000-fold lower than mifepristone. In vivo, CORT125385 treatment did not influence PR-responsive gene expression in the oviduct, while mifepristone treatment strongly influenced these genes in the oviduct, thus excluding in vivo PR cross-reactivity of CORT125385 at a therapeutically active dose. We conclude that CORT125385 is a promising glucocorticoid receptor modulator that effectively reduces liver steatosis in male and female mice without affecting other steroid receptors at doses that lower hepatic lipid content.

Multimodal Data Integration Advances Longitudinal Prediction of the Naturalistic Course of Depression and Reveals a Multimodal Signature of Remission During 2-Year Follow-up.

BACKGROUND: The ability to predict the disease course of individuals with major depressive disorder (MDD) is essential for optimal treatment planning. Here, we used a data-driven machine learning approach to assess the predictive value of different sets of biological data (whole-blood proteomics, lipid metabolomics, transcriptomics, genetics), both separately and added to clinical baseline variables, for the longitudinal prediction of 2-year remission status in MDD at the individual-subject level. METHODS: Prediction models were trained and cross-validated in a sample of 643 patients with current MDD (2-year remission n = 325) and subsequently tested for performance in 161 individuals with MDD (2-year remission n = 82). RESULTS: Proteomics data showed the best unimodal data predictions (area under the receiver operating characteristic curve = 0.68). Adding proteomic to clinical data at baseline significantly improved 2-year MDD remission predictions (area under the receiver operating characteristic curve = 0.63 vs. 0.78, p = .013), while the addition of other omics data to clinical data did not yield significantly improved model performance. Feature importance and enrichment analysis revealed that proteomic analytes were involved in inflammatory response and lipid metabolism, with fibrinogen levels showing the highest variable importance, followed by symptom severity. Machine learning models outperformed psychiatrists' ability to predict 2-year remission status (balanced accuracy = 71% vs. 55%). CONCLUSIONS: This study showed the added predictive value of combining proteomic data, but not other omics data, with clinical data for the prediction of 2-year remission status in MDD. Our results reveal a novel multimodal signature of 2-year MDD remission status that shows clinical potential for individual MDD disease course predictions from baseline measurements.

Conditioning of the Cortisol Awakening Response in Healthy Men: Study Protocol for a Randomized Controlled Trial.

BACKGROUND: The hormone cortisol plays important roles in human circadian and stress physiology and is an interesting target for interventions. Cortisol varies not only in response to stress but also as part of a diurnal rhythm. It shows a particularly sharp increase immediately after awakening, the cortisol awakening response (CAR). Cortisol can be affected by medication, but it is less clear whether it can also be affected by learning. Animal studies have consistently shown that cortisol can be affected by pharmacological conditioning, but the results in humans have been mixed. Other studies have suggested that conditioning is also possible during sleep and that the diurnal rhythm can be conditioned, but these findings have not yet been applied to cortisol conditioning. OBJECTIVE: The objective of our study was to introduce a novel avenue for conditioning cortisol: by using the CAR as an unconditioned response and using scent conditioning while the participant is asleep. This study investigates an innovative way to study the effects of conditioning on cortisol and the diurnal rhythm, using a variety of devices and measures to make measurement possible at a distance and at unusual moments. METHODS: The study protocol takes 2 weeks and is performed from the participant's home. Measures in week 1 are taken to reflect the CAR and waking under baseline conditions. For the first 3 nights of week 2, participants are exposed to a scent from 30 minutes before awakening until their normal time of awakening to allow the scent to become associated with the CAR. On the final night, participants are forced to wake 4 hours earlier, when cortisol levels are normally low, and either the same (conditioned group) or a different (control group) scent is presented half an hour before this new time. This allows us to test whether cortisol levels are higher after the same scent is presented. The primary outcome is the CAR, assessed by saliva cortisol levels, 0, 15, 30, and 45 minutes after awakening. The secondary outcomes are heart rate variability, actigraphy measures taken during sleep, and self-reported mood after awakening. To perform manipulations and measurements, this study uses wearable devices, 2 smartphone apps, web-based questionnaires, and a programmed scent device. RESULTS: We completed data collection as of December 24, 2021. CONCLUSIONS: This study can provide new insights into learning effects on cortisol and the diurnal rhythm. If the procedure does affect the CAR and associated measures, it also has potential clinical implications in the treatment of sleep and stress disorders. TRIAL REGISTRATION: Netherlands Trial Register NL58792.058.16; https://trialsearch.who.int/Trial2.aspx?TrialID=NL7791. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/38087.

Influencing the Insulin System by Placebo Effects in Patients With Diabetes Type 2 and Healthy Controls: A Randomized Controlled Trial.

OBJECTIVE: The objective of this study was to investigate whether placebo effect induced by pharmacological conditioning with intranasal insulin can affect glucose, insulin, C-peptide, hunger, and memory in patients with diabetes type 2 and healthy controls. METHODS: Placebo effect was induced by pharmacological conditioning. Thirty-two older patients (mean age = 68.3 years) with diabetes type 2 and age- and sex-matched thirty-two healthy older adults (mean age = 67.8 years) were randomly assigned to a conditioned or a control group. On day 1, conditioned group received six administrations of intranasal insulin with a conditioned stimulus (CS; smell of rosewood oil), whereas the control group received a placebo with the CS. On day 2, both groups received a placebo spray with the CS. Glucose, insulin, and C-peptide were repeatedly measured in blood. Hunger and memory were assessed with validated measures. RESULTS: Intranasal insulin stabilized dropping glucose levels in patients ( B = 0.03, SE = 0.02, p = .027) and healthy men ( B = 0.046, SE = 0.02, p = .021), and decreased C-peptide levels in healthy controls ( B = 0.01, SE = 0.001, p = .008). Conditioning also prevented the drop of glucose levels but only in men (both healthy and patients; B = 0.001, SE = 0.0003, p = .024). Conditioning significantly decreased hunger in healthy participants ( B = 0.31, SE = 0.09, p < .001). No effects were found on other measures. CONCLUSIONS: Placebo effect induced by conditioning with intranasal insulin modifies blood glucose levels and decreases hunger in older adults, but its effects depend on health status and sex. Insulin conditioning might be beneficial for groups suffering from intensive hunger but seems not be particularly suitable for blood glucose reduction. TRIAL REGISTRATION: Netherlands Trial Register, NL7783 ( https://www.trialregister.nl/trial/7783 ).

Tramadol/paracetamol treatment attenuates the development of collagen antibody-induced arthritis and interferes with prednisolone treatment in mice.

The collagen antibody-induced arthritis (CAIA) model is highly effective in inducing arthritis, making it an attractive model for screening therapeutic compounds such as glucocorticoids (GCs). The severity of discomfort in this model makes it desirable to administer analgesics, but it is a prerequisite that these do not interfere with the model or tested therapeutics. In the present study, we studied the effect of 1 mg/mL tramadol and 3.5 mg/mL paracetamol (TP) on CAIA in male BALB/cAnNCrl mice and the possible interference of TP analgesia with the activity of the GC drug prednisolone (Pred). Our results showed that TP abolished the Pred-induced amelioration of CAIA, as well as several other Pred-induced effects, such as the reduction in thymus weight and the increase in insulin level. This most likely results from the effects of TP on the hepatic metabolism of this drug, since it strongly increased the Cyp3a11 expression in the liver. Altogether, we conclude that TP analgesia is not suitable for the CAIA model in male BALB/cAnNCrl mice, in particular when evaluating the effects of GCs such as Pred.

Stress in adolescence as a first hit in stress-related disease development: Timing and context are crucial.

The two-hit stress model predicts that exposure to stress at two different time-points in life may increase or decrease the risk of developing stress-related disorders later in life. Most studies based on the two-hit stress model have investigated early postnatal stress as the first hit with adult stress as the second hit. Adolescence, however, represents another highly sensitive developmental window during which exposure to stressful events may affect programming outcomes following exposure to stress in adulthood. Here, we discuss the programming effects of different types of stressors (social and nonsocial) occurring during adolescence (first hit) and how such stressors affect the responsiveness toward an additional stressor occurring during adulthood (second hit) in rodents. We then provide a comprehensive overview of the potential mechanisms underlying interindividual and sex differences in the resilience/susceptibility to developing stress-related disorders later in life when stress is experienced in two different life stages.

Transcriptional and cell type profiles of cortical brain regions showing ultradian cortisol rhythm dependent responses to emotional face stimulation.

The characteristic endogenous circadian rhythm of plasma glucocorticoid concentrations is made up from an underlying ultradian pulsatile secretory pattern. Recent evidence has indicated that this ultradian cortisol pulsatility is crucial for normal emotional response in man. In this study, we investigate the anatomical transcriptional and cell type signature of brain regions sensitive to a loss of ultradian rhythmicity in the context of emotional processing. We combine human cell type and transcriptomic atlas data of high spatial resolution with functional magnetic resonance imaging (fMRI) data. We show that the loss of cortisol ultradian rhythm alters emotional processing response in cortical brain areas that are characterized by transcriptional and cellular profiles of GABAergic function. We find that two previously identified key components of rapid non-genomic GC signaling - the ANXA1 gene and retrograde endocannabinoid signaling - show most significant differential expression (q = 3.99e-10) and enrichment (fold enrichment = 5.56, q = 9.09e-4). Our results further indicate that specific cell types, including a specific NPY-expressing GABAergic neuronal cell type, and specific G protein signaling cascades underly the cerebral effects of a loss of ultradian cortisol rhythm. Our results provide a biological mechanistic underpinning of our fMRI findings, indicating specific cell types and cascades as a target for manipulation in future experimental studies.

Structural basis of glucocorticoid receptor signaling bias.

Dissociation between the healthy and toxic effects of cortisol, a major stress-responding hormone has been a widely used strategy to develop anti-inflammatory glucocorticoids with fewer side effects. Such strategy falls short when treating brain disorders as timing and activity state within large-scale neuronal networks determine the physiological and behavioral specificity of cortisol response. Advances in structural molecular dynamics posit the bases for engineering glucocorticoids with precision bias for select downstream signaling pathways. Design of allosteric and/or cooperative control for the glucocorticoid receptor could help promote the beneficial and reduce the deleterious effects of cortisol on brain and behavior in disease conditions.

Peripheral glucocorticoid receptor antagonism by relacorilant with modest HPA axis disinhibition.

Glucocorticoid stress hormones are produced in response to hypothalamic-pituitary-adrenal (HPA) axis activation. Glucocorticoids are essential for physiology and exert numerous actions via binding to the glucocorticoid receptor (GR). Relacorilant is a highly selective GR antagonist currently undergoing a phase 3 clinical evaluation for the treatment of endogenous Cushing's syndrome. It was found that increases in serum adrenocorticotropic hormone (ACTH) and cortisol concentrations after relacorilant treatment were substantially less than the increases typically observed with mifepristone, but it is unclear what underlies these differences. In this study, we set out to further preclinically characterize relacorilant in comparison to the classical but non-selective GR antagonist mifepristone. In human HEK-293 cells, relacorilant potently antagonized dexamethasone- and cortisol-induced GR signaling, and in human peripheral blood mononuclear cells, relacorilant largely prevented the anti-inflammatory effects of dexamethasone. In mice, relacorilant treatment prevented hyperinsulinemia and immunosuppression caused by increased corticosterone exposure. Relacorilant treatment reduced the expression of classical GR target genes in peripheral tissues but not in the brain. In mice, relacorilant induced a modest disinhibition of the HPA axis as compared to mifepristone. In line with this, in mouse pituitary cells, relacorilant was generally less potent than mifepristone in regulating Pomc mRNA and ACTH release. This contrast between relacorilant and mifepristone is possibly due to the distinct transcriptional coregulator recruitment by the GR. In conclusion, relacorilant is thus an efficacious peripheral GR antagonist in mice with only modest disinhibition of the HPA axis, and the distinct properties of relacorilant endorse the potential of selective GR antagonist treatment for endogenous Cushing's syndrome.

Transcriptional glucocorticoid effects in the brain: Finding the relevant target genes.

Glucocorticoids are powerful modulators of brain function. They act via mineralocorticoid and glucocorticoid receptors (MR and GR). These are best understood as transcription factors. Although many glucocorticoid effects depend on the modulation of gene transcription, it is a major challenge to link gene expression to function given the large-scale, apparently pleiotropic genomic responses. The extensive sets of MR and GR target genes are highly specific per cell type, and the brain contains many different (neuronal and non-neuronal) cell types. Next to the set "trait" of cellular context, the "state" of other active signaling pathways will affect MR and GR transcriptional activity. Here, we discuss receptor specificity and contextual factors that determine the transcriptional outcome of MR/GR signaling, experimental possibilities offered by single-cell transcriptomics approaches, and reflect on how to make sense of lists of target genes in relation to understanding the functional effects of steroid receptor activation.

Restricted effects of androgens on glucocorticoid signaling in the mouse prefrontal cortex and midbrain.

Glucocorticoids are key executors of the physiological response to stress. Previous studies in mice showed that the androgen receptor (AR) influenced the transcriptional outcome of glucocorticoid treatment in white and brown adipocytes and in the liver. In the brain, we observed that chronic hypercorticism induced changes in gene expression that tended to be more pronounced in male mice. In the present study, we investigated if glucocorticoid signaling in the brain could be modulated by androgen. After chronic treatment with corticosterone, dihydrotestosterone, a combination of both, and corticosterone in combination with the AR antagonist enzalutamide, we compared the expression of glucocorticoid receptor (NR3C1, also abbreviated GR) target genes in brain regions where AR and GR are co-expressed, namely: prefrontal cortex, hypothalamus, hippocampus, ventral tegmental area and substantia nigra. We observed that androgen affected glucocorticoid signaling only in the prefrontal cortex and the substantia nigra. Dihydrotestosterone and corticosterone independently and inversely regulated expression of Sgk1 and Tsc22d3 in prefrontal cortex. AR antagonism with enzalutamide attenuated corticosterone-induced expression of Fkbp5 in the prefrontal cortex and of Fkbp5 and Sgk1 in the substantia nigra. Additionally, in the substantia nigra, AR antagonism increased expression of Th and Slc18a1, two genes coding for key components of the dopaminergic system. Our data indicate that androgen influence over glucocorticoid stimulation in the brain is not a dominant phenomenon in the context of high corticosterone levels, but can occur in the prefrontal cortex and substantia nigra.

Glucocorticoid Receptor Antagonism Improves Glucose Metabolism in a Mouse Model of Polycystic Ovary Syndrome.

Context: Polycystic ovary syndrome (PCOS) is a complex metabolic disorder associated with obesity, insulin resistance, and dyslipidemia. Hyperandrogenism is a major characteristic of PCOS. Increased androgen exposure is believed to deregulate metabolic processes in various tissues as part of the PCOS pathogenesis, predominantly through the androgen receptor (AR). Notably, various metabolic features in PCOS are similar to those observed after excess glucocorticoid exposure. Objective: We hypothesized that glucocorticoid receptor (GR) signaling is involved in the metabolic symptoms of PCOS. Methods: In a PCOS model of chronic dihydrotestosterone (DHT) exposure in female mice, we investigated whether GR signaling machinery was (de)regulated, and if treatment with a selective GR antagonist alleviated the metabolic symptoms. Results: We observed an upregulation of GR messenger RNA expression in the liver after DHT exposure. In white adipose tissues and liver we found that DHT upregulated Hsd11b1, which encodes for the enzyme that converts inactive into active glucocorticoids. We found that preventive but not therapeutic administration of a GR antagonist alleviated DHT-induced hyperglycemia and restored glucose tolerance. We did not observe strong effects of GR antagonism in DHT-exposed mice on other features like total fat mass and lipid accumulation in various tissues. Conclusion: We conclude that GR activation may play a role in glucose metabolism in DHT-exposed mice.

Do Corticosteroid Receptor mRNA Levels Predict the Expression of Their Target Genes?

The glucocorticoid stress hormones affect brain function via high-affinity mineralocorticoid receptors (MRs) and lower-affinity glucocorticoid receptors (GRs). MR and GR not only differ in affinity for ligands, but also have distinct, sometimes opposite, actions on neuronal excitability and other cellular and higher-order parameters related to cerebral function. GR and MR messenger RNA (mRNA) levels are often used as a proxy for the responsiveness to glucocorticoids, assuming proportionality between mRNA and protein levels. This may be especially relevant for the MR, which because of its high affinity is already largely occupied at low basal (trough) hormone levels. Here we explore how GR and MR mRNA levels are associated with the expression of a shared target gene, glucocorticoid-induced leucine zipper (GILZ, coded by Tsc22d3) with basal and elevated levels of corticosterone in male mice, using in situ hybridization. Depending on the hippocampal subfield and the corticosterone levels, mRNA levels of MR rather than GR mostly correlated with GILZ mRNA in the hippocampus and hypothalamus at the bulk tissue level. At the individual cell level, these correlations were much weaker. Using publicly available single-cell RNA sequencing data, we again observed that MR and GR mRNA levels were only weakly correlated with target gene expression in glutamatergic and GABAergic neurons. We conclude that MR mRNA levels can be limiting for receptor action, but many other cell-specific and region-specific factors ultimately determine corticosteroid receptor action. Altogether, our results argue for caution while interpreting the consequences of changed receptor expression for the response to glucocorticoids.

Immune Modulations by Glucocorticoids: From Molecular Biology to Clinical Research.

Due to their potent anti-inflammatory and immune-suppressive actions, glucocorticoids have been used in the treatment of inflammatory and autoimmune disease for more than 70 years [...].