Comprehensive overview of the structure and regulation of the glucocorticoid receptor

Chemical space exploration with Molpher: Generating and assessing a glucocorticoid receptor ligand library

Computational exploration of chemical space is crucial in modern cheminformatics research for accelerating the discovery of new biologically active compounds. In this study, we present a detailed analysis of the chemical library of potential glucocorticoid receptor (GR) ligands generated by the molecular generator, Molpher. To generate the targeted GR library and construct the classification models, structures from the ChEMBL database as well as from the internal IMG library, which was experimentally screened for biological activity in the primary luciferase reporter cell assay, were utilized. The composition of the targeted GR ligand library was compared with a reference library that randomly samples chemical space. A random forest model was used to determine the biological activity of ligands, incorporating its applicability domain using conformal prediction. It was demonstrated that the GR library is significantly enriched with GR ligands compared to the random library. Furthermore, a prospective analysis demonstrated that Molpher successfully designed compounds, which were subsequently experimentally confirmed to be active on the GR. A collection of 34 potential new GR ligands was also identified. Moreover, an important contribution of this study is the establishment of a comprehensive workflow for evaluating computationally generated ligands, particularly those with potential activity against targets that are challenging to dock.

Glucocorticoid receptor controls atopic dermatitis inflammation via functional interactions with P63 and autocrine signaling in epidermal keratinocytes

Atopic dermatitis (AD), a prevalent chronic inflammatory disease with multifactorial etiology, features epidermal barrier defects and immune overactivation. Synthetic glucocorticoids (GCs) are widely prescribed for treating AD due to their anti-inflammatory actions; however, mechanisms are incompletely understood. Defective local GC signaling due to decreased production of endogenous ligand and/or GC receptor (GR) levels was reported in prevalent inflammatory skin disorders; whether this is a consequence or contributing factor to AD pathology is unclear. To identify the chromatin-bound cell-type-specific GR protein interactome in keratinocytes, we used rapid immunoprecipitation of endogenous proteins and mass spectrometry identifying 145 interactors that increased upon dexamethasone treatment. GR-interacting proteins were enriched in p53/p63 signaling, including epidermal transcription factors with critical roles in AD pathology. Previous analyses indicating mirrored AD-like phenotypes between P63 overexpression and GR loss in epidermis, and our data show an intricate relationship between these transcription factors in human keratinocytes, identifying TP63 as a direct GR target. Dexamethasone treatment counteracted transcriptional up-regulation of inflammatory markers by IL4/IL13, known to mimic AD, causing opposite shifts in GR and P63 genomic binding. Indeed, IL4/IL13 decreased GR and increased P63 levels in cultured keratinocytes and human epidermal equivalents (HEE), consistent with GR down-regulation and increased P63 expression in AD lesions vs normal skin. Moreover, GR knockdown (GRKD) resulted in constitutive increases in P63, phospho-P38 and S100A9, IL6, and IL33. Also, GRKD culture supernatants showed increased autocrine production of TH2-/TH1-/TH17-TH22-associated factors including IL4, CXCL10, CXCL11, and CXCL8. GRKD HEEs showed AD-like features including hyperplasia and abnormal differentiation, resembling phenotypes observed with GR antagonist or IL4/IL13 treatment. The simultaneous GR/P63 knockdown partially reversed constitutive up-regulation of inflammatory genes in GRKD. In summary, our data support a causative role for GR loss in AD pathogenesis via functional interactions with P63 and autocrine signaling in epidermal keratinocytes.

The histone methyltransferase KMT2D maintains cellular glucocorticoid responsiveness by shielding the glucocorticoid receptor from degradation

Because of their ability to induce lymphocyte apoptosis, glucocorticoids (GC) are widely used to treat hematological malignancies such as lymphomas and multiple myeloma. Their effectiveness is often limited, however, due to the development of glucocorticoid resistance by a variety of molecular mechanisms. Here we performed an unbiased genome-wide CRISPR screen with the human T-cell leukemia cell line Jurkat to find previously unidentified genes required for GC-induced apoptosis. One such gene was KMT2D (also known as MLL2 or MLL4), which encodes a histone lysine methyltransferase whose mutations are associated with a variety of cancers, blood malignancies in particular, and are considered markers of poor prognosis. Knockout of KMT2D by CRISPR/Cas9 gene editing in Jurkat and several multiple myeloma cell lines downregulated GR protein expression. Surprisingly, this was not due to a reduction in GR transcripts, but rather to a decrease in the protein's half-life, primarily due to proteasomal degradation. Reconstitution of KMT2D expression restored GR levels. In contrast to the known ability of KMT2D to control gene transcription through covalent histone methylation, KMT2D-mediated upregulation of GR levels did not require its methyltransferase activity. Co-immunoprecipitation and proximity ligation assays found constitutive binding of KMT2D to the GR, which was enhanced in the presence of GC. These observations reveal KMT2D to be essential for the stabilization of cellular GR levels, and suggest a possible mechanism by which KMT2D mutations may lead to GC resistance in some malignancies.

The Glucocorticoid Receptor: Isoforms, Functions, and Contribution to Glucocorticoid Sensitivity

Glucocorticoids exert pleiotropic effects on all tissues to regulate cellular and metabolic homeostasis. Synthetic forms are used therapeutically in a wide range of conditions for their anti-inflammatory benefits, at the cost of dose and duration-dependent side effects. Significant variability occurs between tissues, disease states, and individuals with regard to both the beneficial and deleterious effects. The glucocorticoid receptor (GR) is the site of action for these hormones and a vast body of work has been conducted understanding its function. Traditionally, it was thought that the anti-inflammatory benefits of glucocorticoids were mediated by transrepression of pro-inflammatory transcription factors, while the adverse metabolic effects resulted from direct transactivation. This canonical understanding of the GR function has been brought into question over the past 2 decades with advances in the resolution of scientific techniques, and the discovery of multiple isoforms of the receptor present in most tissues. Here we review the structure and function of the GR, the nature of the receptor isoforms, and the contribution of the receptor to glucocorticoid sensitivity, or resistance in health and disease.

The Interaction of Vasopressin with Hormones of the Hypothalamo-Pituitary-Adrenal Axis: The Significance for Therapeutic Strategies in Cardiovascular and Metabolic Diseases

A large body of evidence indicates that vasopressin (AVP) and steroid hormones are frequently secreted together and closely cooperate in the regulation of blood pressure, metabolism, water-electrolyte balance, and behavior, thereby securing survival and the comfort of life. Vasopressin cooperates with hormones of the hypothalamo-pituitary-adrenal axis (HPA) at several levels through regulation of the release of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and multiple steroid hormones, as well as through interactions with steroids in the target organs. These interactions are facilitated by positive and negative feedback between specific components of the HPA. Altogether, AVP and the HPA cooperate closely as a coordinated functional AVP-HPA system. It has been shown that cooperation between AVP and steroid hormones may be affected by cellular stress combined with hypoxia, and by metabolic, cardiovascular, and respiratory disorders; neurogenic stress; and inflammation. Growing evidence indicates that central and peripheral interactions between AVP and steroid hormones are reprogrammed in cardiovascular and metabolic diseases and that these rearrangements exert either beneficial or harmful effects. The present review highlights specific mechanisms of the interactions between AVP and steroids at cellular and systemic levels and analyses the consequences of the inappropriate cooperation of various components of the AVP-HPA system for the pathogenesis of cardiovascular and metabolic diseases.

Glucocorticoid receptor action in prostate cancer: the role of transcription factor crosstalk

Prostate cancer is one of the most prevalent malignancies and is primarily driven by aberrant androgen receptor (AR) signaling. While AR-targeted therapies form the cornerstone of prostate cancer treatment, they often inadvertently activate compensatory pathways, leading to therapy resistance. This resistance is frequently mediated through changes in transcription factor (TF) crosstalk, reshaping gene regulatory programs and ultimately weakening treatment efficacy. Consequently, investigating TF interactions has become crucial for understanding the mechanisms driving therapy-resistant cancers. Recent evidence has highlighted the crosstalk between the glucocorticoid receptor (GR) and AR, demonstrating that GR can induce prostate cancer therapy resistance by replacing the inactivated AR, thereby becoming a driver of the disease. In addition to this oncogenic role, GR has also been shown to act as a tumor suppressor in prostate cancer. Owing to this dual role and the widespread use of glucocorticoids as adjuvant therapy, it is essential to understand GR's actions across different stages of prostate cancer development. In this review, we explore the current knowledge of GR in prostate cancer, with a specific focus on its crosstalk with other TFs. GR can directly and indirectly interact with a variety of TFs, and these interactions vary significantly depending on the type of prostate cancer cells. By highlighting these crosstalk interactions, we aim to provide insights that can guide the research and development of new GR-targeted therapies to mitigate its harmful effects in prostate cancer.

Fluocinolone Acetonide Implant for Uveitis: Dissecting Responder and Non-Responder Outcomes at a Tertiary Center

Macular edema (ME) remains a primary cause of visual deterioration in uveitis. Visual acuity (VA) can often be maintained using corticosteroid depot systems. This study evaluated the efficacy of a fluocinolone acetonide (FAc) intravitreal implant (ILUVIEN®) in treating non-infectious uveitis using real-world data. This retrospective analysis included 135 eyes subdivided into responders and non-responders. Central retinal thickness (CRT), VA, and intraocular pressure (IOP) were followed over time. A significant decrease in CRT and an increase in VA were observed in all eyes throughout the follow-up period (p < 0.01). An IOP increase (p = 0.028) necessitated treatment in 43% of eyes by Month 6. Non-responders were older (p = 0.004) and had been treated with more dexamethasone (DEX) implants (p = 0.04); 89.3% had a defect in the external limiting membrane (ELM) and inner/outer segment (IS/OS) zone (p < 0.001). Immunomodulatory therapy had no impact on treatment response. Pars plana vitrectomy (PPV) patients had a mean CRT reduction of 47.55 µm and a reduced effect by Month 24 (p = 0.046) versus non-PPV patients. We conclude that the FAc implant achieves long-term control of CRT and improves VA. Increases in IOP were manageable. Eyes with a previous PPV showed milder results. Data showed a correlation between older age, a damaged ELM and IS/OS zone, frequent DEX inserts, and poorer outcome measures.

Inflammatory liver diseases and susceptibility to sepsis

Patients with inflammatory liver diseases, particularly alcohol-associated liver disease and metabolic dysfunction-associated fatty liver disease (MAFLD), have higher incidence of infections and mortality rate due to sepsis. The current focus in the development of drugs for MAFLD is the resolution of non-alcoholic steatohepatitis and prevention of progression to cirrhosis. In patients with cirrhosis or alcoholic hepatitis, sepsis is a major cause of death. As the metabolic center and a key immune tissue, liver is the guardian, modifier, and target of sepsis. Septic patients with liver dysfunction have the highest mortality rate compared with other organ dysfunctions. In addition to maintaining metabolic homeostasis, the liver produces and secretes hepatokines and acute phase proteins (APPs) essential in tissue protection, immunomodulation, and coagulation. Inflammatory liver diseases cause profound metabolic disorder and impairment of energy metabolism, liver regeneration, and production/secretion of APPs and hepatokines. Herein, the author reviews the roles of (1) disorders in the metabolism of glucose, fatty acids, ketone bodies, and amino acids as well as the clearance of ammonia and lactate in the pathogenesis of inflammatory liver diseases and sepsis; (2) cytokines/chemokines in inflammatory liver diseases and sepsis; (3) APPs and hepatokines in the protection against tissue injury and infections; and (4) major nuclear receptors/signaling pathways underlying the metabolic disorders and tissue injuries as well as the major drug targets for inflammatory liver diseases and sepsis. Approaches that focus on the liver dysfunction and regeneration will not only treat inflammatory liver diseases but also prevent the development of severe infections and sepsis.

Acetylation-induced proteasomal degradation of the activated glucocorticoid receptor limits hormonal signaling

Glucocorticoid (GC) signaling is essential for mounting a stress response, however, chronic stress or prolonged GC therapy downregulates the GC receptor (GR), leading to GC resistance. Regulatory mechanisms that refine this equilibrium are not well understood. Here, we identify seven lysine acetylation sites in the amino terminal domain of GR, with lysine 154 (Lys154) in the AF-1 region being the dominant acetyl-acceptor. GR-Lys154 acetylation is mediated by p300/CBP in the nucleus in an agonist-dependent manner and correlates with transcriptional activity. Deacetylation by NAD+-dependent SIRT1 facilitates dynamic regulation of this mark. Notably, agonist-binding to both wild-type GR and an acetylation-deficient mutant elicits similar short-term target gene expression. In contrast, upon extended treatment, the polyubiquitination of the acetylation-deficient GR mutant is impaired resulting in higher protein stability, increased chromatin association and prolonged transactivation. Taken together, reversible acetylation fine-tunes duration of the GC response by regulating proteasomal degradation of activated GR.

Panax notoginseng saponin R1 improves glucocorticoid-inhibited airway epithelium repair via glucocorticoid receptor β

BACKGROUND

Panax notoginseng saponin R1(PNS-R1), derived from Panax notoginseng roots, promotes wound repair, whereas glucocorticoids can inhibit the repair of airway epithelial damage in asthma.

OBJECTIVE

This study investigated whether PNS-R1 counteracts the inhibitory effects of glucocorticoids on the repair of airway epithelial damage in asthma.

METHODS

In vivo, female C57BL/6 mice were sensitized, challenged with house dust mites (HDM), and treated with dexamethasone, PNS-R1, and/or adenovirus GRβ-shRNA. Airway epithelium damage was examined using pathological sections of the trachea and bronchi, markers of airway inflammation, epithelial cells in bronchoalveolar lavage fluid, and expression of the E-cadherin protein. In vitro, we treated 16HBE cells with dexamethasone, PNS-R1, and/or GRβ-siRNA and detected cell proliferation and migration. The expression of GRβ and key components of MKP-1 and Erk1/2 were detected by western blotting.

RESULTS

In vivo, PNS-R1 reduced airway inflammation, hyperresponsiveness, and mucus hypersecretion; the combination of PNS-R1 and dexamethasone promoted airway epithelial integrity and reduced cell detachment. In vitro, PNS-R1 alleviated the inhibition of bronchial epithelial cell growth, migration, and proliferation by dexamethasone; PNS-R1 promoted GRβ expression, inhibited MKP-1 protein expression, and activated MAPK signaling, thereby promoting airway epithelial cell proliferation and repair.

CONCLUSIONS

Panax notoginseng saponin R1 alleviated the inhibitory effect of dexamethasone on the repair of airway epithelial damage in asthmatic mice, likely by promoting the proliferation of airway epithelial cells by stimulating GRβ expression and activating the MAPK pathway.

The glucocorticoid receptor as a master regulator of the Müller cell response to diabetic conditions in mice

Diabetic retinopathy (DR) is considered a primarily microvascular complication of diabetes. Müller glia cells are at the centre of the retinal neurovascular unit and play a critical role in DR. We therefore investigated Müller cell-specific signalling pathways that are altered in DR to identify novel targets for gene therapy. Using a multi-omics approach on purified Müller cells from diabetic db/db mice, we found the mRNA and protein expression of the glucocorticoid receptor (GR) to be significantly decreased, while its target gene cluster was down-regulated. Further, oPOSSUM TF analysis and ATAC- sequencing identified the GR as a master regulator of Müller cell response to diabetic conditions. Cortisol not only increased GR phosphorylation. It also induced changes in the expression of known GR target genes in retinal explants. Finally, retinal functionality was improved by AAV-mediated overexpression of GR in Müller cells. Our study demonstrates an important role of the glial GR in DR and implies that therapeutic approaches targeting this signalling pathway should be aimed at increasing GR expression rather than the addition of more ligand.

Systemic health effects of noise exposure

Noise, any unwanted sound, is pervasive and impacts large populations worldwide. Investigators suggested that noise exposure not only induces auditory damage but also produces various organ system dysfunctions. Although previous reviews primarily focused on noise-induced cardiovascular and cerebral dysfunctions, this narrow focus has unintentionally led the research community to disregard the importance of other vital organs. Indeed, limited studies revealed that noise exposure impacts other organs including the liver, kidneys, pancreas, lung, and gastrointestinal tract. Therefore, the aim of this review was to examine the effects of noise on both the extensively studied organs, the brain and heart, but also determine noise impact on other vital organs. The goal was to illustrate a comprehensive understanding of the systemic effects of noise. These systemic effects may guide future clinical research and epidemiological endpoints, emphasizing the importance of considering noise exposure history in diagnosing various systemic diseases.

Chronic Stress as a Risk Factor for Type 2 Diabetes: Endocrine, Metabolic, and Immune Implications

BACKGROUND

Chronic stress is a condition of pressure on the brain and whole body, which in the long term may lead to a frank disease status, even including type 2 diabetes (T2D). Stress activates the hypothalamus-pituitary-adrenal axis with release of glucocorticoids (GCs) and catecholamines, as well as activation of the inflammatory pathway of the immune system, which alters glucose and lipid metabolism, ultimately leading to beta-cell destruction, insulin resistance and T2D onset. Alteration of the glucose and lipid metabolism accounts for insulin resistance and T2D outcome. Furthermore, stress-related subversion of the intestinal microbiota leads to an imbalance of the gut-brain-immune axis, as evidenced by the stress-related depression often associated with T2D. A condition of generalized inflammation and subversion of the intestinal microbiota represents another facet of stress-induced disease. In fact, chronic stress acts on the gut-brain axis with multiorgan consequences, as evidenced by the association between depression and T2D. Oxidative stress with the production of reactive oxygen species and cytokine-mediated inflammation represents the main hallmarks of chronic stress. ROS production and pro-inflammatory cytokines represent the main hallmarks of stress-related disorders, and therefore, the use of natural antioxidant and anti-inflammatory substances (nutraceuticals) may offer an alternative therapeutic approach to combat stress-related T2D. Single or combined administration of nutraceuticals would be very beneficial in targeting the neuro-endocrine-immune axis, thus, regulating major pathways involved in T2D onset. However, more clinical trials are needed to establish the effectiveness of nutraceutical treatment, dosage, time of administration and the most favorable combinations of compounds. Therefore, in view of their antioxidant and anti-inflammatory properties, the use of natural products or nutraceuticals for the treatment of stress-related diseases, even including T2D, will be discussed. Several evidences suggest that chronic stress represents one of the main factors responsible for the outcome of T2D.

Glucocorticoids, their uses, sexual dimorphisms, and diseases: new concepts, mechanisms, and discoveries

The normal stress response in humans is governed by the hypothalamic-pituitary-adrenal (HPA) axis through heightened mechanisms during stress, raising blood levels of the glucocorticoid hormone cortisol. Glucocorticoids are quintessential compounds that balance the proper functioning of numerous systems in the mammalian body. They are also generated synthetically and are the preeminent therapy for inflammatory diseases. They act by binding to the nuclear receptor transcription factor glucocorticoid receptor (GR), which has two main isoforms (GRα and GRβ). Our classical understanding of glucocorticoid signaling is from the GRα isoform, which binds the hormone, whereas GRβ has no known ligands. With glucocorticoids being involved in many physiological and cellular processes, even small disruptions in their release via the HPA axis, or changes in GR isoform expression, can have dire ramifications on health. Long-term chronic glucocorticoid therapy can lead to a glucocorticoid-resistant state, and we deliberate how this impacts disease treatment. Chronic glucocorticoid treatment can lead to noticeable side effects such as weight gain, adiposity, diabetes, and others that we discuss in detail. There are sexually dimorphic responses to glucocorticoids, and women tend to have a more hyperresponsive HPA axis than men. This review summarizes our understanding of glucocorticoids and critically analyzes the GR isoforms and their beneficial and deleterious mechanisms and the sexual differences that cause a dichotomy in responses. We also discuss the future of glucocorticoid therapy and propose a new concept of dual GR isoform agonist and postulate why activating both isoforms may prevent glucocorticoid resistance.

Luminal breast cancer identity is determined by loss of glucocorticoid receptor activity

Glucocorticoid receptor (GR) is a transcription factor that plays a crucial role in cancer biology. In this study, we utilized an in silico-designed GR activity signature to demonstrate that GR relates to the proliferative capacity of numerous primary cancer types. In breast cancer, the GR activity status determines luminal subtype identity and has implications for patient outcomes. We reveal that GR engages with estrogen receptor (ER), leading to redistribution of ER on the chromatin. Notably, GR activation leads to upregulation of the ZBTB16 gene, encoding for a transcriptional repressor, which controls growth in ER-positive breast cancer and associates with prognosis in luminal A patients. In relation to ZBTB16's repressive nature, GR activation leads to epigenetic remodeling and loss of histone acetylation at sites proximal to cancer-driving genes. Based on these findings, epigenetic inhibitors reduce viability of ER-positive breast cancer cells that display absence of GR activity. Our findings provide insights into how GR controls ER-positive breast cancer growth and may have implications for patients' prognostication and provide novel therapeutic candidates for breast cancer treatment.

Influence of dexamethasone on the interaction between glucocorticoid receptor and SOX9: A molecular dynamics study

The glucocorticoid receptor (GR) is a nuclear receptor that controls critical biological processes by regulating the transcription of specific genes. GR transcriptional activity is modulated by a series of ligands and coenzymes, where a ligand can act as an agonist or antagonist. GR agonists, such as the glucocorticoids dexamethasone (DEX) and prednisolone, are widely prescribed to patients with inflammatory and autoimmune diseases. DEX is also used to induce osteogenic differentiation in vitro. Recently, it has been highlighted that DEX induces changes in the osteogenic differentiation of human mesenchymal stromal cells by downregulating the transcription factor SRY-box transcription factor 9 (SOX9) and upregulating the peroxisome proliferator-activated receptor γ (PPARG). SOX9 is fundamental in the control of chondrogenesis, but also in osteogenesis by acting as a dominant-negative of RUNX2. Many processes remain to be clarified during cell fate determination, such as the interplay between the key transcription factors. The main objective pursued by this work is to shed light on the interaction between GR and SOX9 in the presence and absence of DEX at an atomic level of resolution using molecular dynamics simulations. The outcome of this research could help the understanding of possible molecular interactions between GR and SOX9 and their role in the determination of cell fate. The results highlight the key residues at the interface between GR and SOX9 involved in the complexation process and shed light on the mechanism through which DEX modulates GR-SOX9 binding and exerts its biological activity.

Treating the Side Effects of Exogenous Glucocorticoids; Can We Separate the Good From the Bad?

It is estimated that 2% to 3% of the population are currently prescribed systemic or topical glucocorticoid treatment. The potent anti-inflammatory action of glucocorticoids to deliver therapeutic benefit is not in doubt. However, the side effects associated with their use, including central weight gain, hypertension, insulin resistance, type 2 diabetes (T2D), and osteoporosis, often collectively termed iatrogenic Cushing's syndrome, are associated with a significant health and economic burden. The precise cellular mechanisms underpinning the differential action of glucocorticoids to drive the desirable and undesirable effects are still not completely understood. Faced with the unmet clinical need to limit glucocorticoid-induced adverse effects alongside ensuring the preservation of anti-inflammatory actions, several strategies have been pursued. The coprescription of existing licensed drugs to treat incident adverse effects can be effective, but data examining the prevention of adverse effects are limited. Novel selective glucocorticoid receptor agonists and selective glucocorticoid receptor modulators have been designed that aim to specifically and selectively activate anti-inflammatory responses based upon their interaction with the glucocorticoid receptor. Several of these compounds are currently in clinical trials to evaluate their efficacy. More recently, strategies exploiting tissue-specific glucocorticoid metabolism through the isoforms of 11β-hydroxysteroid dehydrogenase has shown early potential, although data from clinical trials are limited. The aim of any treatment is to maximize benefit while minimizing risk, and within this review we define the adverse effect profile associated with glucocorticoid use and evaluate current and developing strategies that aim to limit side effects but preserve desirable therapeutic efficacy.

In vitro, in vivo, and in silico evaluation of the glucocorticoid receptor antagonist activity of 3,6-dibromocarbazole

3,6-Dibromocarbazole is a novel environmental contaminant which is currently detected in several environmental media worldwide. This work aims to investigate the anti-glucocorticoid potency and endocrine disrupting effects of 3,6-dibromocarbazole. In vitro experiments indicated that 3,6-dibromocarbazole possessed glucocorticoid receptor (GR) antagonistic activity and inhibited dexamethasone-induced GR nuclear translocation. 3,6-Dibromocarbazole reduced the expression levels of glucocorticoid responsive genes including glucose-6-phosphatase (G6Pase), phosphoenolpyruvate carboxykinase (PEPCK), fatty acid synthase (FAS), and tyrosine aminotransferase (TAT), and further disrupted the protein expression of two key enzymes PEPCK and FAS in gluconeogenesis. In vivo experiments showed that 3,6-dibromocarbazole induced abnormal development of zebrafish embryos and disrupted the major neurohormones involved in activation of hypothalamic-pituitary-adrenocortical (HPA) axis in zebrafish larvae. The results of molecular docking and molecular dynamics simulation contributed to explain the antagonistic effect of 3,6-dibromocarbazole. Taken together, this work identified 3,6-dibromocarbazole as a GR antagonist, which might exert endocrine disrupting effects by interfering the pathway of gluconeogenesis.

Endothelial Dysfunction in Cardiorenal Conditions: Implications of Endothelial Glucocorticoid Receptor-Wnt Signaling

The endothelium constitutes the innermost lining of the blood vessels and controls blood fluidity, vessel permeability, platelet aggregation, and vascular tone. Endothelial dysfunction plays a key role in initiating a vascular inflammatory cascade and is the pivotal cause of various devastating diseases in multiple organs including the heart, lung, kidney, and brain. Glucocorticoids have traditionally been used to combat vascular inflammation. Endothelial cells express glucocorticoid receptors (GRs), and recent studies have demonstrated that endothelial GR negatively regulates vascular inflammation in different pathological conditions such as sepsis, diabetes, and atherosclerosis. Mechanistically, the anti-inflammatory effects of GR are mediated, in part, through the suppression of Wnt signaling. Moreover, GR modulates the fatty acid oxidation (FAO) pathway in endothelial cells and hence can influence FAO-mediated fibrosis in several organs including the kidneys. This review summarizes the relationship between GR and Wnt signaling in endothelial cells and the effects of the Wnt pathway in different cardiac and renal diseases. Available data suggest that GR plays a significant role in restoring endothelial integrity, and research on endothelial GR-Wnt interactions could facilitate the development of novel therapies for many cardiorenal conditions.

Glucocorticoid Receptor Signaling in NSCLC: Mechanistic Aspects and Therapeutic Perspectives

Recent advances in non-small cell lung cancer (NSCLC) biology and the discovery of novel therapeutic targets have led to the development of new pharmacological agents that may improve the clinical outcome of patients with NSCLC. The glucocorticoid receptor (GR) is an evolutionarily conserved protein belonging to the nuclear receptor superfamily of transcription factors and mediates the diverse actions of glucocorticoids in cells. Data suggest that the GR may play a relevant role in the molecular mechanisms of NSCLC tumorigenesis and malignant progression. Additionally, evidence indicates that glucocorticoids may affect the efficacy of standard treatment, including chemotherapy, immune checkpoint inhibitors, and targeted therapy. Furthermore, several findings show that GR expression may probably be associated with NSCLC patient survival. Finally, glucocorticoids may be used as therapeutic agents for the clinical management of NSCLC patients. Here, we briefly review the latest advances on the biological role of GR signaling in NSCLC and discuss the potential use of the GR as a prognostic and predictive biomarker. Importantly, we explore the therapeutic potential of glucocorticoids and the effect of adding such drugs to standard therapies for NSCLC.

Glucocorticoids and Their Receptor Isoforms: Roles in Female Reproduction, Pregnancy, and Foetal Development

Alterations in the hypothalamic-pituitary-adrenal (HPA) axis and associated changes in circulating levels of glucocorticoids are integral to an organism's response to stressful stimuli. Glucocorticoids acting via glucocorticoid receptors (GRs) play a role in fertility, reproduction, placental function, and foetal development. GRs are ubiquitously expressed throughout the female reproductive system and regulate normal reproductive function. Stress-induced glucocorticoids have been shown to inhibit reproduction and affect female gonadal function by suppressing the hypothalamic-pituitary-gonadal (HPG) axis at each level. Furthermore, during pregnancy, a mother's exposure to prenatal stress or external glucocorticoids can result in long-lasting alterations to the foetal HPA and neuroendocrine function. Several GR isoforms generated via alternative splicing or translation initiation from the GR gene have been identified in the mammalian ovary and uterus. The GR isoforms identified include the splice variants, GRα and GRβ, and GRγ and GR-P. Glucocorticoids can exert both stimulatory and inhibitory effects and both pro- and anti-inflammatory functions in the ovary, in vitro. In the placenta, thirteen GR isoforms have been identified in humans, guinea pigs, sheep, rats, and mice, indicating they are conserved across species and may be important in mediating a differential response to stress. Distinctive responses to glucocorticoids, differential birth outcomes in pregnancy complications, and sex-based variations in the response to stress could all potentially be dependent on a particular GR expression pattern. This comprehensive review provides an overview of the structure and function of the GR in relation to female fertility and reproduction and discusses the changes in the GR and glucocorticoid signalling during pregnancy. To generate this overview, an extensive non-systematic literature search was conducted across multiple databases, including PubMed, Web of Science, and Google Scholar, with a focus on original research articles, meta-analyses, and previous review papers addressing the subject. This review integrates the current understanding of GR variants and their roles in glucocorticoid signalling, reproduction, placental function, and foetal growth.

Expression of NEAT1 can be used as a predictor for Dex resistance in multiple myeloma patients

OBJECTIVE

Multiple myeloma is a heterogeneous disorder and the intratumor genetic heterogeneity contributes to emergency of drug resistance. Dexamethasone has been used clinically for decades for MM. Nevertheless, their use is severely hampered by the risk of developing side effects and the occurrence of Dex resistance. LncRNA NEAT1 plays a oncogenic role and participates in drug resistance in many solid tumors. Therefore, we investigated a potential usefulness of this molecular as a biomarker for diagnosis of MM and possible correlations of NEAT1 expression with drug resistance and prognosis.

METHODS

Bone marrow and peripheral blood mononuclear cells samples were collected from 60 newly diagnosed MM patients. The expression of NEAT1expression level were detected by quantitative real-time PCR analyses. The relationship about the expression levels of lncRNA with other clinical and cytogenetic features was analyzed. In addition, we measured to analysis the correlation between the expression of NEAT1 and Dex resistance in MM patients.

RESULTS

It was found that the expression of NEAT1 is significantly higher in multiple myeloma patients compared to controls and does not change with other clinical features and cytogenetic features. We further discovered that overexpression of NEAT1 was associated with Dex resistance and a poor prognosis in MM patients.

CONCLUSION

LncRNA NEAT1 has a significant value that might act as a promoting factor in the development of MM and may be severed as a diagnostic factor in MM. NEAT1 invovled in Dex resistance, which provide a new interpretation during the chemotherapy for MM.

Mechanisms underlying corticosteroid resistance in patients with asthma: a review of current knowledge

INTRODUCTION

Corticosteroids are the most cost-effective anti-inflammatory drugs available for the treatment of asthma. Despite their effectiveness, several asthmatic patients have corticosteroid resistance or insensitivity and exhibit a poor response. Corticosteroid insensitivity implies a poor prognosis due to challenges in finding alternative therapeutic options for asthma.

AREAS COVERED

In this review, we describe asthma phenotypes and endotypes, as well as their differential responsiveness to corticosteroids. In addition, we describe the mechanism of action of corticosteroids underlying their regulation of the expression of glucocorticoid receptors (GRs) and their anti-inflammatory effects. Furthermore, we summarize the mechanistic evidence underlying corticosteroid-insensitive asthma, which is mainly related to changes in GR gene expression, structure, and post-transcriptional modifications. Finally, various pharmacological strategies designed to reverse corticosteroid insensitivity are discussed.

EXPERT OPINION

Corticosteroid insensitivity is influenced by the asthma phenotype, endotype, and severity, and serves as an indication for biological therapy. The molecular mechanisms underlying corticosteroid-insensitive asthma have been used to develop targeted therapeutic strategies. However, the lack of clinical trials prevents the clinical application of these treatments.

Emerging Epigenetic and Posttranslational Mechanisms Controlling Resistance to Glucocorticoids in Acute Lymphoblastic Leukemia

Glucocorticoids are extensively used for the treatment of acute lymphoblastic leukemia as they pressure cancer cells to undergo apoptosis. Nevertheless, glucocorticoid partners, modifications, and mechanisms of action are hitherto poorly characterized. This hampers our understanding of therapy resistance, frequently occurring in leukemia despite the current therapeutic combinations using glucocorticoids in acute lymphoblastic leukemia. In this review, we initially cover the traditional view of glucocorticoid resistance and ways of targeting this resistance. We discuss recent progress in our understanding of chromatin and posttranslational properties of the glucocorticoid receptor that might be proven beneficial in our efforts to understand and target therapy resistance. We discuss emerging roles of pathways and proteins such as the lymphocyte-specific kinase that antagonizes glucocorticoid receptor activation and nuclear translocation. In addition, we provide an overview of ongoing therapeutic approaches that sensitize cells to glucocorticoids including small molecule inhibitors and proteolysis-targeting chimeras.

Early Life Stress in Mice Leads to Impaired Colonic Corticosterone Production and Prolonged Inflammation Following Induction of Colitis

BACKGROUND

Early life stress (ELS) is an environmental trigger believed to promote increased risk of IBD. Our goal was to identify mechanisms whereby ELS in mice affects susceptibility to and/or severity of gut inflammation.

METHODS

We utilized 2 published animal models of ELS. In the first model, newborn mice were separated from the dam daily for 4 to 8 hours starting on postnatal day 2 and then weaned early on postnatal day 17. Control mice were left undisturbed with the dams until weaning on postnatal day 21. In the second model, dams were fed dexamethasone or vehicle ad libitum in drinking water on postpartum days 1 to 14. Plasma and colonic corticosterone were measured in juvenile and adult mice. Colitis was induced in 4-week-old mice via intraperitoneal injection of interleukin (IL)-10 receptor blocking antibody every 5 days for 15 days. Five or 15 days later, colitis scores and transcripts for Tnf, glucocorticoid receptors, and steroidogenic enzymes were measured.

RESULTS

Mice exposed to ELS displayed reduced plasma and colonic corticosterone. Control animals showed improvements in indices of inflammation following cessation of interleukin-10 receptor blockade, whereas ELS-exposed animals maintained high levels of Tnf and histological signs of colitis. In colitic animals, prior exposure to ELS was associated with significantly lower expression of genes associated with corticosterone synthesis and responsiveness. Finally, TNF stimulation of colonic crypt cells from ELS mice led to increased inhibition of corticosterone synthesis.

CONCLUSIONS

Our study identifies impaired local glucocorticoid production and responsiveness as a potential mechanism whereby ELS predisposes to chronic colitis in susceptible hosts.

Glucocorticoid Receptor and Ovarian Cancer: From Biology to Therapeutic Intervention

Ovarian cancer (OC) is the leading cause of death from gynecological malignancies worldwide. Fortunately, recent advances in OC biology and the discovery of novel therapeutic targets have led to the development of novel therapeutic agents that may improve the outcome of OC patients. The glucocorticoid receptor (GR) is a ligand-dependent transcriptional factor known for its role in body stress reactions, energy homeostasis and immune regulation. Notably, evidence suggests that GR may play a relevant role in tumor progression and may affect treatment response. In cell culture models, administration of low levels of glucocorticoids (GCs) suppresses OC growth and metastasis. Conversely, high GR expression has been associated with poor prognostic features and long-term outcomes in patients with OC. Moreover, both preclinical and clinical data have shown that GR activation impairs the effectiveness of chemotherapy by inducing the apoptotic pathways and cell differentiation. In this narrative review, we summarize data related to the function and role of GR in OC. To this aim, we reorganized the controversial and fragmented data regarding GR activity in OC and herein describe its potential use as a prognostic and predictive biomarker. Moreover, we explored the interplay between GR and BRCA expression and reviewed the latest therapeutic strategies such as non-selective GR antagonists and selective GR modulators to enhance chemotherapy sensitivity, and to finally provide new treatment options in OC patients.

Spatiotemporal expression pattern of the chicken glucocorticoid receptor during early embryonic development

Glucocorticoids - commonly known as stress hormones - belong to the family of steroid hormones and regulate numerous life essential physiological processes. As lipophilic molecules, glucocorticoids are known to cross the placental barrier in mammals, which - applied for therapeutic reasons or arising from environmental influences - illustrates the role of prenatal stress during embryonic developmental processes. The hormones employ their functions by binding to the glucocorticoid receptor (GR) and thus are involved in regulating the transcription of thousands of genes. Therefore, the aim of this study was to investigate the spatiotemporal expression pattern of the GR during early embryonic vertebrate development, using the chicken embryo as a model organism. The results should contribute to enhance and expand the current understanding of glucocorticoid signaling. By performing in-situ hybridization on whole mount chicken embryos from stage HH10 to HH29 and analyzing vibratome sections of hybridized embryos, we described the spatiotemporal expression pattern of the GR during early embryogenesis. Moreover, we compared the expression pattern of the GR with other developmental markers such as Pax7, Desmin, MyoD and HNK-1 using double in-situ hybridization and immunohistochemistry. We were able to determine the first emergence of GR expression in stage HH13 of chicken development in the cranial area, especially in the muscle anlagen of the branchial arches and of non-somitic neck muscles. Furthermore, we monitored the extension of GR expression pattern throughout later stages and found transcripts of GR during somitogenesis, limb development, myogenesis, neurulation and neural differentiation and moreover during organogenesis of the gastrointestinal organs, the heart, the kidneys and the lungs. Toward later stages, GR expression transitioned from more distinct areas of expression to an increasingly ubiquitous expression pattern. Our results support the notion of an enormous relevance of glucocorticoid signaling during vertebrate embryonic development and contribute to a better understanding of the consequences of prenatal stress and the clinical administration of prenatal glucocorticoids.

The role of the glucocorticoid receptor and its impact on steroid response in moderate-severe COVID-19 patients

The effect of corticosteroid therapy in COVID-19 patients is mediated by its suppressive effect on the regulations of inflammatory response. However, its clinical outcome is often unpredictable. This study aimed to explore the role of glucocorticoid receptors in corticosteroid response in Moderate-Severe COVID-19 patients. In this cross-sectional study, we attempted to find the relationship between the expression of the glucocorticoid receptor (encoded by NR3C1), the variation of glucocorticoid receptors isoform, and the mutations of glucocorticoid receptors exon with clinical response to corticosteroids. In addition, the relationship between glucocorticoid receptors expression and the expression of IκBα (encoded by NFKBIA) and glucocorticoid-induced leucine zipper protein (GILZ; encoded by TSC22D3) as steroid pathways was also evaluated. Thirty-four COVID-19 patients were studied. Blood was drawn before and on day 5 of corticosteroid treatment. Glucocorticoid receptors expression, isoform, and mutation were determined by RNA sequencing from white blood cells. Based on the improvement of clinical and oxygen status, patients were classified into responder and non-responder groups. Of thirty-four patients, 23 (67.6%) showed excellent responses to corticosteroids, and 11 (32.4%) were non-responders. The NR3C1 gene expression was significantly higher in the responsive group at baseline and after five days of glucocorticoid treatment. Isoform variant and mutation of glucocorticoid receptors did not correlate with clinical response. The expression of IκBα and GILZ correlated positively with glucocorticoid receptors expression. This study elucidates the relationship between glucocorticoid receptor expression with therapeutic responses to corticosteroids in moderate-severe COVID-19.

Genetic polymorphisms of glucocorticoid receptor and their association with new-onset diabetes mellitus in kidney transplant recipients

INTRODUCTION

The variability in developing New-onset Diabetes Mellitus After Transplantation (NODAT), together with previously well-established interindividual variation in glucocorticoid sensitivity, led us to hypothesize that polymorphisms in the NR3C1 gene encoding glucocorticoid receptor may alter glucose balance in kidney transplant recipients. This study aimed to evaluate the association of three functional polymorphisms, BclI, N363S, and ER22/23EK, on the NR3C1 gene with NODAT in kidney allograft recipients.

METHODS

From Jun 2020 to July 2022 in Shiraz, 52 patients with NODAT (case group) and 52 non-diabetic kidney transplant recipients (control group) were randomly screened and recruited in this case-control study. The PCR-RFLP technique determined the genotypes of BclI, N363S, and ER22/23EK polymorphisms.

RESULTS

The allelic frequencies of the mutant alleles of BclI, N363S, and ER22/23EK polymorphisms in all patients were 0.36, 0.03, and 0.009, respectively. BclI mutant genotypes (CG and GG) were significantly associated with an increased risk of NODAT (P = 0.016), while the two other polymorphisms disclosed no significant association with NODAT development. In the case group, no significant association was detected between the onset time of NODAT and studied polymorphisms, including BclI (P = 0.43), N363S (P = 0.30), and ER22/23EK. P value was not reported for the last polymorphism because all patients with NODAT had the wild-type genotype (GG/GG) and performing statistical analysis was not feasible. Among studied demographic/clinical/paraclinical variables, factors such as higher mean trough level of tacrolimus during the first month after transplantation and higher mean daily dose of prednisolone significantly linked with NODAT development.

CONCLUSION

Our data suggested that BclI polymorphism significantly affects NODAT development among Iranian kidney allograft recipients.

Postoperative systemic inflammatory dysregulation and corticosteroids: a narrative review

In some patients, the inflammatory-immune response to surgical injury progresses to a harmful, dysregulated state. We posit that postoperative systemic inflammatory dysregulation forms part of a pathophysiological response to surgical injury that places patients at increased risk of complications and subsequently prolongs hospital stay. In this narrative review, we have outlined the evolution, measurement and prediction of postoperative systemic inflammatory dysregulation, distinguishing it from a healthy and self-limiting host response. We reviewed the actions of glucocorticoids and the potential for heterogeneous responses to peri-operative corticosteroid supplementation. We have then appraised the evidence highlighting the safety of corticosteroid supplementation, and the potential benefits of high/repeated doses to reduce the risks of major complications and death. Finally, we addressed how clinical trials in the future should target patients at higher risk of peri-operative inflammatory complications, whereby corticosteroid regimes should be tailored to modify not only the a priori risk, but also further adjusted in response to markers of an evolving pathophysiological response.

Context-Dependent Role of Glucocorticoid Receptor Alpha and Beta in Breast Cancer Cell Behaviour

Background. The dual role of GCs has been observed in breast cancer; however, due to many concomitant factors, GR action in cancer biology is still ambiguous. In this study, we aimed to unravel the context-dependent action of GR in breast cancer. Methods. GR expression was characterized in multiple cohorts: (1) 24,256 breast cancer specimens on the RNA level, 220 samples on the protein level and correlated with clinicopathological data; (2) oestrogen receptor (ER)-positive and -negative cell lines were used to test for the presence of ER and ligand, and the effect of the GRβ isoform following GRα and GRβ overexpression on GR action, by in vitro functional assays. Results. We found that GR expression was higher in ER- breast cancer cells compared to ER+ ones, and GR-transactivated genes were implicated mainly in cell migration. Immunohistochemistry showed mostly cytoplasmic but heterogenous staining irrespective of ER status. GRα increased cell proliferation, viability, and the migration of ER- cells. GRβ had a similar effect on breast cancer cell viability, proliferation, and migration. However, the GRβ isoform had the opposite effect depending on the presence of ER: an increased dead cell ratio was found in ER+ breast cancer cells compared to ER- ones. Interestingly, GRα and GRβ action did not depend on the presence of the ligand, suggesting the role of the "intrinsic", ligand-independent action of GR in breast cancer. Conclusions. Staining differences using different GR antibodies may be the reason behind controversial findings in the literature regarding the expression of GR protein and clinicopathological data. Therefore, caution in the interpretation of immunohistochemistry should be applied. By dissecting the effects of GRα and GRβ, we found that the presence of the GR in the context of ER had a different effect on cancer cell behaviour, but independently of ligand availability. Additionally, GR-transactivated genes are mostly involved in cell migration, which raises GR's importance in disease progression.

Glucocorticoid receptor hypersensitivity enhances inflammatory signaling and inhibits cell cycle progression in porcine PBMCs

The consequences of glucocorticoid receptor (GR) hypersensitivity during infection have so far received little attention. We previously discovered that a natural gain-of-function Ala610Val substitution in the porcine GR aggravates response of pigs to lipopolysaccharide (LPS)-induced endotoxemia, which can be alleviated by dexamethasone (DEX) pretreatment. In this work, we investigated the relevant molecular basis of these phenotypes by transcriptomic profiling of porcine peripheral blood mononuclear cells (PBMCs) carrying different GR genotypes, in unstimulated conditions or in response to DEX and/or LPS in vitro. The Val allele differentially regulated abunda+nt genes in an additive-genetic manner. A subset of more than 200 genes was consistently affected by the substitution across treatments. This was associated with upregulation of genes related i.a. to endo-lysosomal system, lipid and protein catabolism, and immune terms including platelet activation, and antigen presentation, while downregulated genes were mainly involved in cell cycle regulation. Most importantly, the set of genes constitutively upregulated by Val includes members of the TLR4/LPS signaling pathway, such as LY96. Consequently, when exposing PBMCs to LPS treatment, the Val variant upregulated a panel of additional genes related to TLR4 and several other pattern recognition receptors, as well as cell death and lymphocyte signaling, ultimately amplifying the inflammatory responses. In contrast, when stimulated by DEX treatment, the Val allele orchestrated several genes involved in anti-inflammatory responses during infection. This study provides novel insights into the impact of GR hypersensitivity on the fate and function of immune cells, which may be useful for endotoxemia therapy.

Associations of RPEL1 and miR-1307 gene polymorphisms with disease susceptibility, glucocorticoid efficacy, anxiety, depression, and health-related quality of life in Chinese systemic lupus erythematosus patients

OBJECTIVE

Our present study intended to examine the associations of RPEL1 and miR-1307 gene polymorphisms (rs4917385 and rs7911488) with susceptibility, glucocorticoids (GCs) efficacy, anxiety, depression, and health-related quality of life (HRQoL) in Chinese systemic lupus erythematosus (SLE) patients.

METHODS

Initially, 1000 participants (500 SLE cases and 500 controls) were recruited for the case-control study. Then, 429 cases who received GCs were followed through 12 weeks to explore GCs efficacy, depression, anxiety, and HRQoL. We selected the iMLDR technique for genotyping: RPEL1: rs4917385 (G/T) and miR-1307: rs7911488 (A/G).

RESULTS

The minor G allele of rs7911488 reduced the risk of SLE (p = .024). Four haplotypes consisting of rs4917385 and rs7911488 were associated with SLE susceptibility (p < .025). Both rs4917385 and rs7911488 were associated with anxiety symptoms and physical function (PF) in SLE patients (p < .025). The rs4917385 was associated with depression and its improvement. No statistical significance was found between RPEL1 and miR-1307 gene polymorphisms with GCs efficacy. Meanwhile, additive interaction analysis showed a significant association between RPEL1 and miR-1307 gene polymorphisms with tea consumption in anxiety.

CONCLUSION

RPEL1 and miR-1307 gene polymorphisms (rs4917385 and rs7911488) might be related to SLE susceptibility in Chinese population. Additionally, the two polymorphisms were possibly associated with depression, anxiety, and HRQoL in Chinese SLE population.

Single nucleotide polymorphisms in surfactant protein A1 are not associated with a lack of responsiveness to antenatal steroid therapy in a pregnant sheep model

Treatment with antenatal steroids (ANS) is standard practice for reducing the risk of respiratory distress in the preterm infant. Despite clear overall benefits when appropriately administered, many fetuses fail to derive benefit from ANS therapies. In standardized experiments using a pregnant sheep model, we have demonstrated that around 40% of ANS-exposed lambs did not have functional lung maturation significantly different from that of saline-treated controls. Surfactant protein A is known to play an important role in lung function. In this genotyping study, we investigated the potential correlation between polymorphisms in SFTPA1, messenger RNA and protein levels, and ventilation outcomes in animals treated with ANS. 45 preterm lambs were delivered 48 h after initial ANS therapy and 44 lambs were delivered 8 days after initial ANS therapy. The lambs were ventilated for 30 min after delivery. SFTPA1 mRNA expression in lung tissue was not correlated with arterial blood PaCO2 values at 30 min of ventilation in lambs delivered 48 h after treatment. SFTPA1 protein in lung tissue was significantly correlated with PaCO2 at 30 min of ventilation in lambs ventilated both 48 h and 8 days after ANS treatment. Six different single nucleotide polymorphisms (SNPs) in the Ovis aries SFTPA1 sequence were detected by Sanger Sequencing. No individual SNPs or SNP haplotypes correlated with alterations in PaCO2 at 30 min of ventilation or SFTPA1 protein levels in the lung. For the subset of animals analyzed in the present study, variable lung maturation responses to ANS therapy were not associated with mutations in SFTPA1.

Interactions between nuclear receptors glucocorticoid receptor α and peroxisome proliferator-activated receptor α form a negative feedback loop

Both nuclear receptors glucocorticoid receptor α (GRα) and peroxisome proliferator-activated receptor α (PPARα) are involved in energy and lipid metabolism, and possess anti-inflammation effects. Previous studies indicate that a regulatory loop may exist between them. In vivo and in vitro studies showed that glucocorticoids stimulate hepatic PPARα expression via GRα at the transcriptional level. This stimulation of PPARα by GRα has physiological relevance and PPARα is involved in many glucocorticoid-induced pathophysiological processes, including gluconeogenesis and ketogenesis during fasting, insulin resistance, hypertension and anti-inflammatory effects. PPARα also synergizes with GRα to promote erythroid progenitor self-renewal. As the feedback, PPARα inhibits glucocorticoid actions at pre-receptor and receptor levels. PPARα decreases glucocorticoid production through inhibiting the expression and activity of type-1 11β-hydroxysteroid dehydrogenase, which converts inactive glucocorticoids to active glucocorticoids at local tissues, and also down-regulates hepatic GRα expression, thus forming a complete and negative feedback loop. This negative feedback loop sheds light on prospective multi-drug therapeutic treatments in inflammatory diseases through a combination of glucocorticoids and PPARα agonists. This combination may potentially enhance the anti-inflammatory effects while alleviating side effects on glucose and lipid metabolism due to GRα activation. More investigations are needed to clarify the underlying mechanism and the relevant physiological or pathological significance of this regulatory loop.

Narrative Review: Glucocorticoids in Alcoholic Hepatitis—Benefits, Side Effects, and Mechanisms

Alcoholic hepatitis is a major health and economic burden worldwide. Glucocorticoids (GCs) are the only first-line drugs recommended to treat severe alcoholic hepatitis (sAH), with limited short-term efficacy and significant side effects. In this review, I summarize the major benefits and side effects of GC therapy in sAH and the potential underlying mechanisms. The review of the literature and data mining clearly indicate that the hepatic signaling of glucocorticoid receptor (GR) is markedly impaired in sAH patients. The impaired GR signaling causes hepatic down-regulation of genes essential for gluconeogenesis, lipid catabolism, cytoprotection, and anti-inflammation in sAH patients. The efficacy of GCs in sAH may be compromised by GC resistance and/or GC’s extrahepatic side effects, particularly the side effects of intestinal epithelial GR on gut permeability and inflammation in AH. Prednisolone, a major GC used for sAH, activates both the GR and mineralocorticoid receptor (MR). When GC non-responsiveness occurs in sAH patients, the activation of MR by prednisolone might increase the risk of alcohol abuse, liver fibrosis, and acute kidney injury. To improve the GC therapy of sAH, the effort should be focused on developing the biomarker(s) for GC responsiveness, liver-targeting GR agonists, and strategies to overcome GC non-responsiveness and prevent alcohol relapse in sAH patients.

Is the glucocorticoid receptor a key player in prostate cancer?: A literature review

Glucocorticoids act through the glucocorticoid receptor (GR) and exert pleiotropic effects in different cancer types. In prostate cancer cells, GR and androgen receptor (AR) share overlapping transcriptomes and cistromes. Under enzalutamide treatment, GR signaling can bypass AR activation and promote castration resistance via the expression of a subset of AR-target genes. However, GR-dependent growth under enhanced antiandrogen inhibition occurs only in a subset of primed cells. On the other hand, glucocorticoids have been used successfully in the treatment of prostate cancer for many years. In the context of AR signaling, GR competes with AR for DNA-binding and has the potential to halt the proliferation rate of prostate cancer cells. Their target genes overlap by <50% and they execute unique functions in vivo. In addition, even when AR and GR upregulate the same transcriptional target gene, the effect might not be identical in magnitude. Besides being able to drive tumor proliferation, GR is also a key player in prostate cancer cell survival. Stimulation of GR activity can undermine the effects of enhanced antiandrogen treatment, chemotherapy and radiotherapy. GR activation in prostate cancer can increase prosurvival gene expression. Identifying the full spectrum of GR activity will inform the optimal use of glucocorticosteroids in prostate cancer. It will also determine the best strategies to target the protumorigenic effects of GR.

Distinct Patterns of GR Transcriptional Regulation in Liver and Muscle of LPS-Challenged Weaning Piglets

Glucocorticoid receptor (GR), which is ubiquitously expressed in nearly all cell types of various organs, mediates the tissue-specific metabolic and immune responses to maintain homeostasis and ensure survival under stressful conditions or pathological challenges. The neonatal period is metabolically demanding, and piglets are subjected to multiple stressors in modern intensive farms, especially around weaning. The liver is more responsive to LPS challenge compared to muscle, which is indicated by significantly increased TLR4 and p-p65, TNF-α, and IL-6 levels in association with GR down-regulation at both mRNA and protein levels. GR binding to the putative nGRE on TNF-α and IL-6 gene promoters decreased in the liver, but not muscle, upon LPS stimulation. The transcriptional regulation of GR also showed striking differences between liver and muscle. GR exon 1 mRNA variants 1–4, 1–5, and 1–6 were down-regulated in both liver and muscle, but a significant up-regulation of GR exon 1–9/10 mRNA variants abolished the change of total GR mRNA in the muscle in response to LPS stimulation. The significant down-regulation of GR in the liver corresponded with significantly decreased binding of p-GR and diminished histone acetylation in GR gene promoters. These results indicate that tissue-specific GR transcriptional regulation is involved in the differential inflammation responses between liver and muscle.

The Role of Conformational Dynamics and Allostery in the Control of Distinct Efficacies of Agonists to the Glucocorticoid Receptor

Glucocorticoid receptor (GR) regulates various cellular functions. Given its broad influence on metabolic activities, it has been the target of drug discovery for decades. However, how drugs induce conformational changes in GR has remained elusive. Herein, we used five GR agonists (dex, AZ938, pred, cor, and dibC) with different efficacies to investigate which aspect of the ligand induced the differences in efficacy. We performed molecular dynamics simulations on the five systems (dex-, AZ938-, pred-, cor-, and dibC-bound systems) and observed a distinct discrepancy in the conformation of the cofactor TIF2. Moreover, we discovered ligand-induced differences regarding the level of conformational changes posed by the binding of cofactor TIF2 and identified a pair of essential residues D590 and T39. We further found a positive correlation between the efficacies of ligands and the interaction of the two binding pockets’ domains, where D590 and T739 were involved, implying their significance in the participation of allosteric communication. Using community network analysis, two essential communities containing D590 and T739 were identified with their connectivity correlating to the efficacy of ligands. The potential communication pathways between these two residues were revealed. These results revealed the underlying mechanism of allosteric communication between the ligand-binding and cofactor-binding pockets and identified a pair of important residues in the allosteric communication pathway, which can serve as a guide for future drug discovery.

Betamethasone Dipropionate Derivatization, Biotransformation, Molecular Docking, and ADME Analysis as Glucocorticoid Receptor

Betamethasone is an important glucocorticoids (GCs), frequently used to cure allergies (such as asthma and angioedema), Crohn's disease, skin diseases (such as dermatitis and psoriasis), systemic lupus erythematosus, rheumatic disorders, and leukemia. Present investigation deals to find potential agonist of glucocorticoid receptors after biotransformation of betamethasone dipropionate (1) and to carry out the molecular docking and ADME analyses. Biotransformation of 1 was carried out with Launaea capitata (dandy) roots and Musa acuminate (banana) leaves. M. acuminate furnished low-cost value-added products such as Sananone dipropionate (2) in 5% yields. Further, biocatalysis of Sananone dipropionate (2) with M. acuminate gave Sananone propionate (3) and Sananone (4) in 12% and 7% yields, respectively. However, Sananone (4) was obtained in 37% yields from Launaea capitata. Compound 5 was obtained in 11% yield after β-elimination of propionic acid at C-17 during oxidation of compound 1. The structure elucidation of new compounds 2-5 was accomplished through combined use of X-ray diffraction and NMR (1D and 2D) studies. In addition to this, molecular docking and ADME analyses of all transformed products of 1 were also done. Compounds 1-5 showed -12.53 to -10.11 kcal/mol potential binding affinity with glucocorticoid receptor (GR) and good ADME profile. Moreover, all the compounds showed good oral bioavailability with the octanol/water partition coefficient in the range of 2.23 to 3.65, which indicated that compounds 1-5 were in significant agreement with the given criteria to be considered as drug-like.

Paternal eNOS deficiency in mice affects glucose homeostasis and liver glycogen in male offspring without inheritance of eNOS deficiency itself

AIMS/HYPOTHESIS

It was shown that maternal endothelial nitric oxide synthase (eNOS) deficiency causes fatty liver disease and numerically lower fasting glucose in female wild-type offspring, suggesting that parental genetic variants may influence the offspring's phenotype via epigenetic modifications in the offspring despite the absence of a primary genetic defect. The aim of the current study was to analyse whether paternal eNOS deficiency may cause the same phenotype as seen with maternal eNOS deficiency.

METHODS

Heterozygous (+/-) male eNOS (Nos3) knockout mice or wild-type male mice were bred with female wild-type mice. The phenotype of wild-type offspring of heterozygous male eNOS knockout mice was compared with offspring from wild-type parents.

RESULTS

Global sperm DNA methylation decreased and sperm microRNA pattern altered substantially. Fasting glucose and liver glycogen storage were increased when analysing wild-type male and female offspring of +/- eNOS fathers. Wild-type male but not female offspring of +/- eNOS fathers had increased fasting insulin and increased insulin after glucose load. Analysing candidate genes for liver fat and carbohydrate metabolism revealed that the expression of genes encoding glucocorticoid receptor (Gr; also known as Nr3c1) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (Pgc1a; also known as Ppargc1a) was increased while DNA methylation of Gr exon 1A and Pgc1a promoter was decreased in the liver of male wild-type offspring of +/- eNOS fathers. The endocrine pancreas in wild-type offspring was not affected.

CONCLUSIONS/INTERPRETATION

Our study suggests that paternal genetic defects such as eNOS deficiency may alter the epigenome of the sperm without transmission of the paternal genetic defect itself. In later life wild-type male offspring of +/- eNOS fathers developed increased fasting insulin and increased insulin after glucose load. These effects are associated with increased Gr and Pgc1a gene expression due to altered methylation of these genes.

Role of glucocorticoid receptor mutations in hypertension and adrenal gland hyperplasia

Hypertension is one of the leading causes of premature death in humans and exhibits a complex aetiology including environmental and genetic factors. Mutations within the glucocorticoid receptor (GR) can cause glucocorticoid resistance, which is characterized by several clinical features like hypercortisolism, hypokalaemia, adrenal hyperplasia and hypertension. Altered glucocorticoid receptor signalling further affects sodium and potassium homeostasis as well as blood pressure regulation and cell proliferation and differentiation that influence organ development and function. In salt-sensitive hypertension, excessive renal salt transport and sympathetic nervous system stimulation may occur simultaneously, and, thus, both the mineralocorticoid receptor (MR) and the GR-signalling may be implicated or even act interdependently. This review focuses on identified GR mutations in human primary generalized glucocorticoid resistance (PGGR) patients and their related clinical phenotype with specific emphasis on adrenal gland hyperplasia and hypertension. We compare these findings to mouse and rat mutants harbouring genetically engineered mutations to further dissect the cause and/or the consequence of clinical features which are common or different.

How to tame your genes: mechanisms of inflammatory gene repression by glucocorticoids

Glucocorticoids (GCs) are widely used therapeutic agents to treat a broad range of inflammatory conditions. Their functional effects are elicited by binding to the glucocorticoid receptor (GR), which regulates transcription of distinct gene networks in response to ligand. However, the mechanisms governing various aspects of undesired side effects versus beneficial immunomodulation upon GR activation remain complex and incompletely understood. In this review, we discuss emerging models of inflammatory gene regulation by GR, highlighting GR's regulatory specificity conferred by context-dependent changes in chromatin architecture and transcription factor or co-regulator dynamics. GR controls both gene activation and repression, with the repression mechanism being central to favorable clinical outcomes. We describe current knowledge about 3D genome organization and its role in spatiotemporal transcriptional control by GR. Looking beyond, we summarize the evidence for dynamics in gene regulation by GR through cooperative convergence of epigenetic modifications, transcription factor crosstalk, molecular condensate formation and chromatin looping. Further characterizing these genomic events will reframe our understanding of mechanisms of transcriptional repression by GR.

Crosstalk of hepatocyte nuclear factor 4a and glucocorticoid receptor in the regulation of lipid metabolism in mice fed a high-fat-high-sugar diet

Background

Hepatocyte nuclear factor 4α (HNF4α) and glucocorticoid receptor (GR), master regulators of liver metabolism, are down-regulated in fatty liver diseases. The present study aimed to elucidate the role of down-regulation of HNF4α and GR in fatty liver and hyperlipidemia.

Methods

Adult mice with liver-specific heterozygote (HET) and knockout (KO) of HNF4α or GR were fed a high-fat-high-sugar diet (HFHS) for 15 days. Alterations in hepatic and circulating lipids were determined with analytical kits, and changes in hepatic mRNA and protein expression in these mice were quantified by real-time PCR and Western blotting. Serum and hepatic levels of bile acids were quantified by LC-MS/MS. The roles of HNF4α and GR in regulating hepatic gene expression were determined using luciferase reporter assays.

Results

Compared to HFHS-fed wildtype mice, HNF4α HET mice had down-regulation of lipid catabolic genes, induction of lipogenic genes, and increased hepatic and blood levels of lipids, whereas HNF4α KO mice had fatty liver but mild hypolipidemia, down-regulation of lipid-efflux genes, and induction of genes for uptake, synthesis, and storage of lipids. Serum levels of chenodeoxycholic acid and deoxycholic acid tended to be decreased in the HNF4α HET mice but dramatically increased in the HNF4α KO mice, which was associated with marked down-regulation of cytochrome P450 7a1, the rate-limiting enzyme for bile acid synthesis. Hepatic mRNA and protein expression of sterol-regulatory-element-binding protein-1 (SREBP-1), a master lipogenic regulator, was induced in HFHS-fed HNF4α HET mice. In reporter assays, HNF4α cooperated with the corepressor small heterodimer partner to potently inhibit the transactivation of mouse and human SREBP-1C promoter by liver X receptor. Hepatic nuclear GR proteins tended to be decreased in the HNF4α KO mice. HFHS-fed mice with liver-specific KO of GR had increased hepatic lipids and induction of SREBP-1C and PPARγ, which was associated with a marked decrease in hepatic levels of HNF4α proteins in these mice. In reporter assays, GR and HNF4α synergistically/additively induced lipid catabolic genes.

Conclusions

induction of lipid catabolic genes and suppression of lipogenic genes by HNF4α and GR may mediate the early resistance to HFHS-induced fatty liver and hyperlipidemia.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-022-01654-6.

Targeting Nuclear Receptors in Lung Cancer—Novel Therapeutic Prospects

Lung cancer, the second most commonly diagnosed cancer, is the major cause of fatalities worldwide for both men and women, with an estimated 2.2 million new incidences and 1.8 million deaths, according to GLOBOCAN 2020. Although various risk factors for lung cancer pathogenesis have been reported, controlling smoking alone has a significant value as a preventive measure. In spite of decades of extensive research, mechanistic cues and targets need to be profoundly explored to develop potential diagnostics, treatments, and reliable therapies for this disease. Nuclear receptors (NRs) function as transcription factors that control diverse biological processes such as cell growth, differentiation, development, and metabolism. The aberrant expression of NRs has been involved in a variety of disorders, including cancer. Deregulation of distinct NRs in lung cancer has been associated with numerous events, including mutations, epigenetic modifications, and different signaling cascades. Substantial efforts have been made to develop several small molecules as agonists or antagonists directed to target specific NRs for inhibiting tumor cell growth, migration, and invasion and inducing apoptosis in lung cancer, which makes NRs promising candidates for reliable lung cancer therapeutics. The current work focuses on the importance of various NRs in the development and progression of lung cancer and highlights the different small molecules (e.g., agonist or antagonist) that influence NR expression, with the goal of establishing them as viable therapeutics to combat lung cancer.

Antenatal Steroids and Cord Blood T-cell Glucocorticoid Receptor DNA Methylation and Exon 1 Splicing

Antenatal administration of glucocorticoids such as betamethasone (BMZ) during the late preterm period improves neonatal respiratory outcomes. However, glucocorticoids may elicit programming effects on immune function and gene regulation. Here, we test the hypothesis that exposure to antenatal BMZ alters cord blood immune cell composition in association with altered DNA methylation and alternatively expressed Exon 1 transcripts of the glucocorticoid receptor (GR) gene in cord blood CD4⁺ T-cells. Cord blood was collected from 51 subjects in the Antenatal Late Preterm Steroids Trial: 27 BMZ, 24 placebo. Proportions of leukocytes were compared between BMZ and placebo. In CD4+ T-cells, methylation at CpG sites in the GR promoter regions and expression of GR mRNA exon 1 variants were compared between BMZ and placebo. BMZ was associated with an increase in granulocytes (51.6% vs. 44.7% p = 0.03) and a decrease in lymphocytes (36.8% vs. 43.0% p = 0.04) as a percent of the leukocyte population vs. placebo. Neither GR methylation nor exon 1 transcript levels differed between groups. BMZ is associated with altered cord blood leukocyte proportions, although no associated alterations in GR methylation were observed.

Hippocampal interneurons are direct targets for circulating glucocorticoids

The hippocampus has become a significant target of stress research in recent years because of its role in cognitive functioning, neuropathology, and regulation of the hypothalamic-pituitary-adrenal (HPA) axis. Despite the pervasive impact of stress on psychiatric and neurological disease, many of the circuit- and cell-dependent mechanisms giving rise to the limbic regulation of the stress response remain unknown. Hippocampal excitatory neurons generally express high levels of glucocorticoid receptors (GRs) and are therefore positioned to respond directly to serum glucocorticoids. These neurons are, in turn, regulated by neighboring interneurons, subtypes of which have been shown to respond to stress exposure. However, GR expression among hippocampal interneurons is not well characterized. To determine whether key interneuron populations are direct targets for glucocorticoid action, we used two transgenic mouse lines to label parvalbumin-positive (PV+) and somatostatin-positive (SST+) interneurons. GR immunostaining of labeled interneurons was characterized within the dorsal and ventral dentate hilus, dentate cell body layer, and CA1 and CA3 stratum oriens and stratum pyramidale. While nearly all hippocampal SST+ interneurons expressed GR across all regions, GR labeling of PV+ interneurons showed considerable subregion variability. The percentage of PV+, GR+ cells was highest in the CA3 stratum pyramidale and lowest in the CA1 stratum oriens, with other regions showing intermediate levels of expression. Together, these findings indicate that, under baseline conditions, hippocampal SST+ interneurons are a ubiquitous glucocorticoid target, while only distinct populations of PV+ interneurons are direct targets. This anatomical diversity suggests functional differences in the regulation of stress-dependent hippocampal responses.

The power of the (imperfect) palindrome: Sequence-specific roles of palindromic motifs in gene regulation

In human languages, a palindrome reads the same forward as backward (e.g., 'madam'). In regulatory DNA, a palindrome is an inverted sequence repeat that allows a transcription factor to bind as a homodimer or as a heterodimer with another type of transcription factor. Regulatory palindromes are typically imperfect, that is, the repeated sequences differ in at least one base pair, but the functional significance of this asymmetry remains poorly understood. Here, we review the use of imperfect palindromes in Drosophila photoreceptor differentiation and mammalian steroid receptor signaling. Moreover, we discuss mechanistic explanations for the predominance of imperfect palindromes over perfect palindromes in these two gene regulatory contexts. Lastly, we propose to elucidate whether specific imperfectly palindromic variants have specific regulatory functions in steroid receptor signaling and whether such variants can help predict transcriptional outcomes as well as the response of individual patients to drug treatments.