Glucocorticoid Action Research Articles

Glucocorticoid-Induced Leucine Zipper (GILZ) in Cardiovascular Health and Disease.

Glucocorticoids (GCs) are essential in regulating functions and homeostasis in many biological systems and are extensively used to treat a variety of conditions associated with immune/inflammatory processes. GCs are among the most powerful drugs for the treatment of autoimmune and inflammatory diseases, but their long-term usage is limited by severe adverse effects. For this reason, to envision new therapies devoid of typical GC side effects, research has focused on expanding the knowledge of cellular and molecular effects of GCs. GC-induced leucine zipper (GILZ) is a GC-target protein shown to mediate several actions of GCs, including inhibition of the NF-κB and MAPK pathways. GILZ expression is not restricted to immune cells, and it has been shown to play a regulatory role in many organs and tissues, including the cardiovascular system. Research on the role of GILZ on endothelial cells has demonstrated its ability to modulate the inflammatory cascade, resulting in a downregulation of cytokines, chemokines, and cellular adhesion molecules. GILZ also has the capacity to protect myocardial cells, as its deletion makes the heart, after a deleterious stimulus, more susceptible to apoptosis, immune cell infiltration, hypertrophy, and impaired function. Despite these advances, we have only just begun to appreciate the relevance of GILZ in cardiovascular homeostasis and dysfunction. This review summarizes the current understanding of the role of GILZ in modulating biological processes relevant to cardiovascular biology.

Genomic and Non-Genomic Actions of Glucocorticoids on Adipose Tissue Lipid Metabolism.

Glucocorticoids (GCs) are hormones that aid the body under stress by regulating glucose and free fatty acids. GCs maintain energy homeostasis in multiple tissues, including those in the liver and skeletal muscle, white adipose tissue (WAT), and brown adipose tissue (BAT). WAT stores energy as triglycerides, while BAT uses fatty acids for heat generation. The multiple genomic and non-genomic pathways in GC signaling vary with exposure duration, location (adipose tissue depot), and species. Genomic effects occur directly through the cytosolic GC receptor (GR), regulating the expression of proteins related to lipid metabolism, such as ATGL and HSL. Non-genomic effects act through mechanisms often independent of the cytosolic GR and happen shortly after GC exposure. Studying the effects of GCs on adipose tissue breakdown and generation (lipolysis and adipogenesis) leads to insights for treatment of adipose-related diseases, such as obesity, coronary disease, and cancer, but has led to controversy among researchers, largely due to the complexity of the process. This paper reviews the recent literature on the genomic and non-genomic effects of GCs on WAT and BAT lipolysis and proposes research to address the many gaps in knowledge related to GC activity and its effects on disease.

Anaerobic digestion of sewage sludge has no effect on glucocorticoid and anti-progestagenic activity but increases estrogenicity three-fold

Although the recovery and beneficial reuse of organic matter and nutrients from sludge represents an important move towards environmental sustainability, the accumulation of chemicals in biosolid-amended soils could pose serious environmental and human health risks. However, (eco)toxicological profiling of complex chemical mixtures in biosolids is currently limited. In particular, the effect of anaerobic digestion (AD), the most common stabilization process for sewage sludge, on the (eco)toxicity of those complex mixtures is poorly studied. In this work, we fill this research gap by applying an effect-based monitoring approach to screen sludge samples (n = 4) from a full-scale sewage treatment plant before and after conventional mesophilic (37 °C) AD using a battery of cell-based in vitro bioassays for four types of hormonal activity: estrogenic, androgenic, progestagenic and glucocorticoid activity, both in agonist and antagonist modes. We detected estrogenic, glucocorticoid and anti-progestagenic activity in all sludge samples. The glucocorticoid and anti-progestagenic activity remained mostly unchanged after AD treatment, but estrogenicity increased three-fold, likely as a result of bioactivation processes in the digestor. This study presents the first report on the concentration and fate of glucocorticoid and anti-progestagenic activity in AD. Future research should apply bioanalytical tools to a wider range of sludge samples to get a better understanding of the typical hormonal activity in sludge and develop effect-based trigger (EBT) values for biosolids to help interpret the risk posed by the hormonal activity detected in sludge.

Sex-Dependent Changes of miRNA Levels in the Hippocampus of Adrenalectomized Rats Following Acute Corticosterone Administration.

We explored sex-biased effects of the primary stress glucocorticoid hormone corticosterone on the miRNA expression profile in the rat hippocampus. Adult adrenalectomized (ADX) female and male rats received a single corticosterone (10 mg/kg) or vehicle injection, and after 6 h, hippocampi were collected for miRNA, mRNA, and Western blot analyses. miRNA profiling microarrays showed a basal sex-biased miRNA profile in ADX rat hippocampi. Additionally, acute corticosterone administration triggered a sex-biased differential expression of miRNAs derived from genes located in several chromosomes and clusters on the X and 6 chromosomes. Putative promoter analysis unveiled that most corticosterone-responsive miRNA genes contained motifs for either direct or indirect glucocorticoid actions in both sexes. The evaluation of transcription factors indicated that almost 50% of miRNA genes sensitive to corticosterone in both sexes was under glucocorticoid receptor regulation. Transcription factor-miRNA regulatory network analyses identified several transcription factors that regulate, activate, or repress miRNA expression. Validated target mRNA analysis of corticosterone-responsive miRNAs showed a more complex miRNA-mRNA interaction network in males compared to females. Enrichment analysis revealed that several hippocampal-relevant pathways were affected in both sexes, such as neurogenesis and neurotrophin signaling. The evaluation of selected miRNA targets from these pathways displayed a strong sex difference in the hippocampus of ADX-vehicle rats. Corticosterone treatment did not change the levels of the miRNA targets and their corresponding tested proteins. Our data indicate that corticosterone exerts a sex-biased effect on hippocampal miRNA expression, which may engage in sculpting the basal sex differences observed at higher levels of hippocampal functioning.

DHEAS and Differential Blood Counts as Indirect Signs of Glucocorticoid Excess in Adrenal Non-Producing Adenomas.

The majority of incidentally discovered adrenal tumors are later characterized as non-producing adrenocortical adenomas (NPA). We asked whether laboratory abnormalities in parameters that reflect glucocorticoid action can be found in patients with NPA despite their nature of being clinically unapparent. Since glucocorticoids are potent immunosuppressants we studied blood counts and differential blood counts along with corticotropin and dehydroepiandrostenedione sulfate (DHEAS) blood concentrations, as well as cortisol values before and after an overnight 1 mg dexamethasone suppression test. We compared the results of normal individuals, of patients with adrenal adenomas and normal hormone profiles and with subclinical autonomous glucocorticoid hypersecretion, as well as overt cortisol excess. We found that almost all indices of the blood counts were significantly different between the patients groups. In particular, patients with adrenal non-producing adenomas already showed signs of glucocorticoid excess, including relative lymphocytopenia, lowered DHEAS, and ACTH concentrations than control individuals. We also found that the extent of lymphocytopenia correlated with the concentrations of DHEAS and ACTH, and DHEAS correlated well with ACTH. We conclude that the basal ACTH and DHEAS values along with the differential blood counts give good information on the extent of glucocorticoid excess and that silent adrenal adenomas seem to oversecrete glucocorticoids at concentrations that already alter these parameters.

Combinatorial actions of glucocorticoid and mineralocorticoid stress hormone receptors are required for preventing neurodegeneration of the mouse hippocampus

Chronic stress contributes to numerous human pathologies including cognition impairments and psychiatric disorders. Glucocorticoids are primary stress hormones that activate two closely related nuclear receptors, the glucocorticoid (GR) and mineralocorticoid receptor (MR), that are both highly expressed in the hippocampus. To investigate potential combinatorial actions of hippocampal GR and MR, we developed mice with conditional knockout of both GR and MR in the hippocampus and compared them to their single knockout counterparts. Mice lacking MR alone or both GR and MR in the hippocampus exhibited altered expression of multiple CA2-specific neuronal markers and enhanced cue-dependent learning in a conditioned fear test. Provocatively, in contrast to the single knockouts, mice depleted of both GR and MR showed profound neurodegeneration of the hippocampus. Neuronal death was increased and neurogenesis was reduced in the dentate gyrus of the double knockout mice. Global gene expression assays of the knockout mice revealed a synergistic increase in the number of dysregulated genes in the hippocampus lacking both GR and MR. This large cohort of genes reliant on both GR and MR for expression was strongly associated with cell death and cell proliferation pathways. GR/MR complexes were detected in CA1 and dentate gyrus neurons suggesting receptor heterodimers contribute to the joint actions of GR and MR. These findings reveal an obligate role for MR signaling in regulating the molecular phenotype of CA2 neurons and demonstrate that combinatorial actions of GR and MR are essential for preserving dentate gyrus neurons and maintaining hippocampal health.

Antiviral Effect of Budesonide against SARS-CoV-2.

Treatment options for COVID-19, a disease caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, are currently severely limited. Therefore, antiviral drugs that efficiently reduce SARS-CoV-2 replication or alleviate COVID-19 symptoms are urgently needed. Inhaled glucocorticoids are currently being discussed in the context of treatment for COVID-19, partly based on a previous study that reported reduced recovery times in cases of mild COVID-19 after inhalative administration of the glucocorticoid budesonide. Given various reports that describe the potential antiviral activity of glucocorticoids against respiratory viruses, we aimed to analyze a potential antiviral activity of budesonide against SARS-CoV-2 and circulating variants of concern (VOC) B.1.1.7 (alpha) and B.1.351 (beta). We demonstrate a dose-dependent inhibition of SARS-CoV-2 that was comparable between all viral variants tested while cell viability remains unaffected. Our results are encouraging as they could indicate a multimodal mode of action of budesonide against SARS-CoV-2 and COVID-19, which could contribute to an improved clinical performance.

A guide to changing paradigms of glucocorticoid receptor function-a model system for genome regulation and physiology.

The glucocorticoid receptor (GR) is a bona fide ligand-regulated transcription factor. Cloned in the 80s, the GR has become one of the best-studied and clinically most relevant members of the nuclear receptor superfamily. Cooperative activity of GR with other transcription factors and a plethora of coregulators contribute to the tissue- and context-specific response toward the endogenous and pharmacological glucocorticoids (GCs). Furthermore, nontranscriptional activities in the cytoplasm are emerging as an additional function of GR. Over the past 40years, the concepts of GR mechanisms of action had been constantly changing. Different methodologies in the pregenomic and genomic era of molecular biological research and recent cutting-edge technology in single-cell and single-molecule analysis are steadily evolving the views, how the GR in particular and transcriptional regulation in general act in physiological and pathological processes. In addition to the development of technologies for GR analysis, the use of model organisms provides insights how the GR invivo executes GC action in tissue homeostasis, inflammation, and energy metabolism. The model organisms, namely the mouse, but also rats, zebrafish, and recently fruit flies carrying mutations of the GR became a major driving force to analyze the molecular function of GR in disease models. This guide provides an overview of the exciting research and paradigm shifts in the GR field from past to present with a focus on GR transcription factor networks, GR DNA-binding and single-cell analysis, and model systems.

Glucocorticoid receptor triggers a reversible drug-tolerant dormancy state with acquired therapeutic vulnerabilities in lung cancer

The glucocorticoid receptor (GR) regulates gene expression, governing aspects of homeostasis, but is also involved in cancer. Pharmacological GR activation is frequently used to alleviate therapy-related side-effects. While prior studies have shown GR activation might also have anti-proliferative action on tumours, the underpinnings of glucocorticoid action and its direct effectors in non-lymphoid solid cancers remain elusive. Here, we study the mechanisms of glucocorticoid response, focusing on lung cancer. We show that GR activation induces reversible cancer cell dormancy characterised by anticancer drug tolerance, and activation of growth factor survival signalling accompanied by vulnerability to inhibitors. GR-induced dormancy is dependent on a single GR-target gene, CDKN1C, regulated through chromatin looping of a GR-occupied upstream distal enhancer in a SWI/SNF-dependent fashion. These insights illustrate the importance of GR signalling in non-lymphoid solid cancer biology, particularly in lung cancer, and warrant caution for use of glucocorticoids in treatment of anticancer therapy related side-effects.

Glucocorticoids: Fuelling the Fire of Atherosclerosis or Therapeutic Extinguishers?

Glucocorticoids are steroid hormones with key roles in the regulation of many physiological systems including energy homeostasis and immunity. However, chronic glucocorticoid excess, highlighted in Cushing’s syndrome, is established as being associated with increased cardiovascular disease (CVD) risk. Atherosclerosis is the major cause of CVD, leading to complications including coronary artery disease, myocardial infarction and heart failure. While the associations between glucocorticoid excess and increased prevalence of these complications are well established, the mechanisms underlying the role of glucocorticoids in development of atheroma are unclear. This review aims to better understand the importance of glucocorticoids in atherosclerosis and to dissect their cell-specific effects on key processes (e.g., contractility, remodelling and lesion development). Clinical and pre-clinical studies have shown both athero-protective and pro-atherogenic responses to glucocorticoids, effects dependent upon their multifactorial actions. Evidence indicates regulation of glucocorticoid bioavailability at the vasculature is complex, with local delivery, pre-receptor metabolism, and receptor expression contributing to responses linked to vascular remodelling and inflammation. Further investigations are required to clarify the mechanisms through which endogenous, local glucocorticoid action and systemic glucocorticoid treatment promote/inhibit atherosclerosis. This will provide greater insights into the potential benefit of glucocorticoid targeted approaches in the treatment of cardiovascular disease.

Glucocorticoid and mineralocorticoid receptor expression in critical illness: A narrative review.

The glucocorticoid receptor (GCR) and the mineralocorticoid receptor (MR) are members of the steroid receptor superfamily of hormone-dependent transcription factors. The receptors are structurally and functionally related. They are localized in the cytosol and translocate into the nucleus after ligand binding. GCRs and MRs can be co-expressed within the same cell, and it is believed that the balance in GCR and MR expression is crucial for homeostasis and plays a key role in normal adaptation. In critical illness, the hypothalamic-pituitary-adrenal axis is activated, and as a consequence, serum cortisol concentrations are high. However, a number of patients exhibit relatively low cortisol levels for the degree of illness severity. Glucocorticoid (GC) actions are facilitated by GCR, whose dysfunction leads to GC tissue resistance. The MR is unique in this family in that it binds to both aldosterone and cortisol. Endogenous GCs play a critical role in controlling inflammatory responses in critical illness. Intracellular GC concentrations can differ greatly from blood levels due to the action of the two 11β-hydroxysteroid dehydrogenase isozymes, type 1 and type 2. 11β-hydroxysteroid dehydrogenases interconvert endogenous active cortisol and intrinsically inert cortisone. The degree of expression of the two isozymes has the potential to dramatically influence local GC availability within cells and tissues. In this review, we will explore the clinical studies that aimed to elucidate the role of MR and GCR expression in the inflammatory response seen in critical illness.

Chronic glucocorticoid treatment induces hepatic lipid accumulation and hyperinsulinaemia in part through actions on AgRP neurons

Glucocorticoids (GCs) are widely prescribed anti-inflammatory medicines, but their use can lead to metabolic side-effects. These may occur through direct actions of GCs on peripheral organs, but could also be mediated by the hypothalamic AgRP neurons, which can increase food intake and modify peripheral metabolism. Therefore, the aim of this study was to examine the metabolic effects of chronic treatment with the GC corticosterone (Cort, 75 μg/ml in drinking water) in mice lacking the glucocorticoid receptor (GR) on AgRP neurons. Female AgRP-GR KO mice had delayed onset of Cort-induced hyperphagia. However, AgRP-GR KO had little impact on the increased body weight or adiposity seen with 3 weeks Cort treatment. Cort caused hepatic steatosis in control mice, but in Cort treated female AgRP-GR KO mice there was a 25% reduction in liver lipid content and lower plasma triglycerides. Additionally, Cort treatment led to hyperinsulinaemia, but compared to controls, Cort-treated AgRP-GR KO mice had both lower fasting insulin levels and lower insulin levels during a glucose tolerance test. In conclusion, these data indicate that GCs do act through AgRP neurons to contribute, at least in part, to the adverse metabolic consequences of chronic GC treatment.

Overview and Management of Glucocorticoid-Induced Hyperglycemia in Pulmonary Diseases: Insight into the COVID-19 Pandemic

Background: Glucocorticoids are potent anti-inflammatory agents that have become an integral component of the standard of care for numerous pathologies. Their wide-ranging uses and efficacy in different treatment pathways are not without important adverse events to consider. Glucocorticoid-induced hyperglycemia remains a prominent issue but the optimal management is understudied. Pulmonary diseases represent a large disease group in which glucocorticoids have shown clinical benefits. Glucocorticoid-induced hyperglycemia in pulmonary disease has been associated with adverse patient outcomes. The coronavirus disease 2019 (COVID-19) pandemic has now introduced a novel indication for glucocorticoids and has further highlighted that hyperglycemia results in increased mortality. Methods: Here we review literature-based epidemiology, clinical outcomes, and treatment of glucocorticoid-induced hyperglycemia in chronic obstructive pulmonary disease, asthma, and most recently, COVID-19. Lastly, we provide a comprehensive review of the outcomes related to hyperglycemia, implications of glucocorticoid treatment, and treatment approaches to hyperglycemia in the COVID-19 pandemic. Conclusion: Management of people with diabetes requiring glucocorticoid therapy can be complex and require aggressive treatment. Awareness of the prevalence of hyperglycemia, attention to insulin and glucocorticoid action profiles, and treatment options can assist in improving glycemic outcomes.

Aberrant Level of Estrogen Correlates with Defective Thrombopoiesis during Pregnancy in Patients with Immune Thrombocytopenia

AbstractPregnancy seems to be a high-risk event in immune thrombocytopenia(ITP)because disease flares are frequently observed during gestation clinically, and the treatment with glucocorticoid is often ineffective. Sex hormones are changed dramatically during pregnancy to maintain a stable environment both for the mother and for the fetus. To determine the sex hormone levels during pregnancy in ITP, sex hormones were analyzed in patients with ITP and matched healthy women before, during, and after pregnancy. We demonstrated that there is a relationship between estrogen level and thrombopoiesis in ITP pregnancy. Moreover, we showed that estrogen plays a role in glucocorticoid resistance which is common in ITP patients who are pregnant.Thirty consecutive successful pregnancies in 30 patients with ITP, 21 pregnancies in 21 healthy controls, twenty patients with primary ITP and 19 healthy subjects were studied. Serum samples for sex hormone testing, including estrogen, progesterone, testosterone, prolactin, LH and FSH, were collected and analyzed. We confirmed that serum levels of all sex hormones varied significantly during pregnancy and postpartum, both in the patients with ITP and in healthy controls, as expected. However, the concentration of estrogen was significantly lower in pregnant ITP patients, compared with healthy pregnant subjects, leading to a completely different profile.To clarify whether the different estrogen concentration has a direct effect on megakaryocyte(MK) maturation and thrombopoiesis during pregnancy in ITP, BM-derived CD34+ cells from ITP patients and healthy controls in pregnancy, were treated with different doses of estrogen. We found that estrogen had the ability to promote MK polyploidization, maturation and proplatelet formation via estrogen receptor(ER) in healthy controls, but the concentration of estrogen, which was lower than that of the normal-pregnancy group, could not play the above role in CD34+ cells of pregnancy-ITP group. To determine the differences in MKs treated with estrogen of different doses in each group, we screened some essential transcription factors that may participate in the regulation of MK polyploidization and maturation. The expression levels of GATA1, FLI1, FOG-1, KLF-1, and NF-E2, were detected by RT-PCR and Western blot. We found that, in the pregnancy-ITP group treated with lower estrogen, the expression of GATA1 and NF-E2 was significantly reduced compared with the healthy control. We obtained similar results with the bone marrow samples, indicating that pregnant ITP patients showed more obvious detects in megakaryocyte maturation defect and lower expression of transcription factors. Further investigation is needed to evaluate the expression of ER and its nuclear translocation in MKs of the pregnancy-ITP group treated with the relatively lower level of estrogen.We also explored if the relatively reduced estrogen level plays a role in glucocorticoid resistance which is commonly observed in ITP patients during pregnancy. We evaluated the inhibitory effects of dexamethasone, with or without different concentrations of estrogen, on the proliferation of PBMCs from the pregnancy-ITP group induced by a mitogen. We found that estrogen impaired the inhibitory effects of dexamethasone. Further study with immunofluorescence demonstrated that estrogen upregulated the expression of protein phosphatase, which affected the glucocorticoid receptor activation.In conclusion, an unexpected lack of estrogen serum level increase occurs in patients with ITP during pregnancy. The relatively reduced level of estrogen cannot induce the expression of GATA1 and NF-E2 via ER in pregnant ITP patients, which is required for MK maturation and thrombopoiesis. Meanwhile, setrogen inhibits glucocorticoid action via protein phosphatase, which may account for the glucocorticoid resistance observed in pregnant ITP patients. DisclosuresNo relevant conflicts of interest to declare.

Associations of trauma and posttraumatic stress disorder with aldosterone in women

BackgroundPosttraumatic stress disorder (PTSD) has been associated with increased cardiovascular risk, however, underlying mechanisms have not been fully specified. PTSD is associated with stress-related hormones, including dysregulated glucocorticoid activity. Dysregulation of aldosterone, a mineralocorticoid activated by psychological stress and implicated in cardiovascular damage, may be a relevant pathway linking PTSD and cardiovascular risk. Few studies to date have evaluated the association between PTSD and aldosterone, none with repeated measures of aldosterone. We examined if trauma and PTSD were associated with altered aldosterone levels relative to women unexposed to trauma. MethodsThe association of trauma exposure and chronic PTSD with plasma aldosterone levels was investigated in 521 middle-aged women in the Nurses’ Health Study II. Aldosterone was assessed at two time points, 10–16 years apart, and trauma exposure and PTSD were also ascertained for both time points. Regarding exposure assessment, women were characterized based on a structured diagnostic interview as: having chronic PTSD (PTSD at both time points; n = 174); being trauma-exposed (trauma exposure at first time point but no PTSD; n = 174); and being unexposed (no trauma exposure at either time point; reference group for all analyses; n = 173). Linear mixed models examined associations of trauma and PTSD status with log-transformed aldosterone levels, adjusting for covariates and health-related variables that may confound or lie on the pathway between PTSD and altered aldosterone levels. ResultsAcross the sample, mean aldosterone concentration decreased over time. Adjusting for covariates, women with chronic PTSD had significantly lower aldosterone levels averaged over time, compared to women unexposed to trauma (β = − 0.08, p = 0.04). Interactions between trauma/PTSD group and time were not significant, indicating change in aldosterone over time did not differ by trauma/PTSD status. Post-hoc exploratory analyses suggested that menopausal status partially mediated the relationship between chronic PTSD status and aldosterone level, such that postmenopausal status explained 7% of the effect of PTSD on aldosterone. ConclusionsThese findings indicate that PTSD is associated with lower levels of aldosterone. Further work is needed to understand implications of this type of dysregulation in a key biological stress system for cardiovascular and other health outcomes previously linked with PTSD.

Dexamethasone for Severe COVID-19: How Does It Work at Cellular and Molecular Levels?

The coronavirus disease 2019 (COVID-19) caused by infection of the severe respiratory syndrome coronavirus-2 (SARS-CoV-2) significantly impacted human society. Recently, the synthetic pure glucocorticoid dexamethasone was identified as an effective compound for treatment of severe COVID-19. However, glucocorticoids are generally harmful for infectious diseases, such as bacterial sepsis and severe influenza pneumonia, which can develop respiratory failure and systemic inflammation similar to COVID-19. This apparent inconsistency suggests the presence of pathologic mechanism(s) unique to COVID-19 that renders this steroid effective. We review plausible mechanisms and advance the hypothesis that SARS-CoV-2 infection is accompanied by infected cell-specific glucocorticoid insensitivity as reported for some other viruses. This alteration in local glucocorticoid actions interferes with undesired glucocorticoid to facilitate viral replication but does not affect desired anti-inflammatory properties in non-infected organs/tissues. We postulate that the virus coincidentally causes glucocorticoid insensitivity in the process of modulating host cell activities for promoting its replication in infected cells. We explore this tenet focusing on SARS-CoV-2-encoding proteins and potential molecular mechanisms supporting this hypothetical glucocorticoid insensitivity unique to COVID-19 but not characteristic of other life-threatening viral diseases, probably due to a difference in specific virally-encoded molecules and host cell activities modulated by them.

The Function of the Hypothalamic-Pituitary-Adrenal Axis During Experimental Autoimmune Encephalomyelitis: Involvement of Oxidative Stress Mediators.

Multiple sclerosis (MS) is an inflammatory, demyelinating disease with an unknown origin. Previous studies showed the involvement of the hypothalamic–pituitary–adrenal (HPA) axis to susceptibility to autoimmune diseases, including MS, and its best-characterized animal model, experimental autoimmune encephalomyelitis (EAE). During MS/EAE, innate immune cells are activated and release cytokines and other inflammatory mediators, leading to a vicious cycle of inflammation. In response to inflammation, the activated HPA axis modulates immune responses via glucocorticoid activity. Because the mechanisms involving oxidative stress to the HPA axis are relatively unrevealed, in this study, we investigate the inflammatory and oxidative stress status of HPA axis during EAE. Our results reveal an upregulation of Pomc gene expression, followed by POMC and ACTH protein increase at the peak of the EAE in the pituitary. Also, prostaglandins are well-known contributors of HPA axis activation, which increases during EAE at the periphery. The upregulated Tnf expression in the pituitary during the peak of EAE occurred. This leads to the activation of oxidative pathways, followed by upregulation of inducible NO synthase expression. The reactive oxidant/nitrosative species (ROS/RNS), such as superoxide anion and NO, increase their levels at the onset and peak of the disease in the pituitary and adrenal glands, returning to control levels at the end of EAE. The corticotrophs in the pituitary increased in number and volume at the peak of EAE that coincides with high lipid peroxidation levels. The expression of MC2R in the adrenal glands increases at the peak of EAE, where strong induction of superoxide anion and malondialdehyde (MDA), reduced total glutathione (GSH) content, and catalase activity occurred at the peak and end of EAE compared with controls. The results obtained from this study may help in understanding the mechanisms and possible pharmacological modulation in MS and demonstrate an effect of oxidative stress exposure in the HPA activation during the course of EAE.

Protection of Antigen-Primed Effector T Cells From Glucocorticoid-Induced Apoptosis in Cell Culture and in a Mouse Model of Multiple Sclerosis.

Induction of T cell apoptosis constitutes a major mechanism by which therapeutically administered glucocorticoids (GCs) suppress inflammation and associated clinical symptoms, for instance in multiple sclerosis (MS) patients suffering from an acute relapse. The sensitivity of T cells to GC action depends on their maturation and activation status, but the precise effect of antigen-priming in a pathological setting has not been explored. Here we used transgenic and congenic mouse models to compare GC-induced apoptosis between naïve and antigen-specific effector T cells from mice immunized with a myelin peptide. Antigen-primed effector T cells were protected from the pro-apoptotic activity of the synthetic GC dexamethasone in a dose-dependent manner, which resulted in their accumulation relative to naïve T cells in vitro and in vivo. Notably, the differential sensitivity of T cells to GC-induced apoptosis correlated with their expression level of the anti-apoptotic proteins Bcl-2 and Bcl-XL and a loss of the mitochondrial membrane potential. Moreover, accumulation of antigen-primed effector T cells following GC treatment in vitro resulted in an aggravated disease course in an adoptive transfer mouse model of MS in vivo, highlighting the clinical relevance of the observed phenomenon. Collectively, our data indicate that antigen-priming influences the T cells’ sensitivity to therapeutically applied GCs in the context of inflammatory diseases.

Venlafaxine and L-Thyroxine Treatment Combination: Impact on Metabolic and Synaptic Plasticity Changes in an Animal Model of Coexisting Depression and Hypothyroidism.

The clinical effectiveness of supportive therapy with thyroid hormones in drug-resistant depression is well-known; however, the mechanisms of action of these hormones in the adult brain have not been fully elucidated to date. We determined the effects of venlafaxine and/or L-thyroxine on metabolic parameters and markers involved in the regulation of synaptic plasticity and cell damage in an animal model of coexisting depression and hypothyroidism, namely, Wistar Kyoto rats treated with propylthiouracil. In this model, in relation to the depression model itself, the glycolysis process in the brain was weakened, and a reduction in pyruvate dehydrogenase in the frontal cortex was normalized only by the combined treatment with L-thyroxine and venlafaxine, whereas changes in pyruvate and lactate levels were affected by all applied therapies. None of the drugs improved the decrease in the expression of mitochondrial respiratory chain enzymes. No intensification of glucocorticoid action was shown, while an unfavorable change caused by the lack of thyroid hormones was an increase in the caspase-1 level, which was not reversed by venlafaxine alone. The results indicated that the combined administration of drugs was more effective in normalizing glycolysis and the transition to the Krebs cycle than the use of venlafaxine or L-thyroxine alone.

Adrenal tumors provide insight into the role of cortisol in NK cell activity.

Elevated glucocorticoid (GC) activity may limit tumor immune response and immune checkpoint inhibitor (ICI) efficacy. Adrenocortical carcinoma (ACC) provides a unique test case to assess correlates of GC activity, as approximately half of ACC patients exhibit excess GC production (GC+). ACC multi-omics were analyzed to identify molecular consequences of GC+ and assess the rationale for combining the glucocorticoid receptor (GR) antagonist relacorilant with an ICI. GC status, mRNA expression, and DNA mutation and methylation data from 71 adrenal tumors were accessed via The Cancer Genome Atlas. Expression of 858 genes differed significantly between GC- and GC+ ACC cases. KEGG pathway analysis showed higher gene expression of three pathways involved in steroid synthesis and secretion in GC+ cases. Fifteen pathways, most related to NK cells and other immune activity, showed lower expression. Hypomethylation was primarily observed in the steroid synthesis pathways. Tumor-infiltrating CD4+ memory (P = 0.003), CD8+ memory (P < 0.001), and NKT-cells (P = 0.014) were depleted in GC+ cases; tumor-associated neutrophils were enriched (P < 0.001). Given the pronounced differences between GC+ and GC- ACC, the effects of cortisol on NK cells were assessed in vitro (NK cells from human PBMCs stimulated with IL-2 or IL-12/15). Cortisol suppressed, and relacorilant restored, NK cell activation, proliferation, and direct tumor cell killing. Thus, GR antagonism may increase the abundance and function of NK and other immune cells in the tumor microenvironment, promoting immune response in GC+ ACC and other malignancies with GC+. This hypothesis will be tested in a phase 1 trial of relacorilant + ICI.