Will we ever have better glucocorticoids?

Glucocorticoid therapy for acute respiratory distress syndrome: Current concepts

Acute respiratory distress syndrome (ARDS), a fatal critical disease, is induced by various insults. ARDS represents a major global public health burden, and the management of ARDS continues to challenge healthcare systems globally, especially during the pandemic of the coronavirus disease 2019 (COVID-19). There remains no confirmed specific pharmacotherapy for ARDS, despite advances in understanding its pathophysiology. Debate continues about the potential role of glucocorticoids (GCs) as a promising ARDS clinical therapy. Questions regarding GC agent, dose, and duration in patients with ARDS need to be answered, because of substantial variations in GC administration regimens across studies. ARDS heterogeneity likely affects the therapeutic actions of exogenous GCs. This review includes progress in determining the GC mechanisms of action and clinical applications in ARDS, especially during the COVID-19 pandemic.

Identification of FDA-approved drugs that increase mevalonate kinase in hyper IgD syndrome

Mevalonate kinase deficiency (MKD) is an autoinflammatory metabolic disorder caused by bi-allelic loss-of-function variants in the MVK gene, resulting in decreased activity of the encoded mevalonate kinase (MK). Clinical presentation ranges from the severe early-lethal mevalonic aciduria to the milder hyper-IgD syndrome (MKD-HIDS), and is in the majority of patients associated with recurrent inflammatory episodes with often unclear cause. Previous studies with MKD-HIDS patient cells indicated that increased temperature, as caused by fever during an inflammatory episode, lowers the residual MK activity, which causes a temporary shortage of non-sterol isoprenoids that promotes the further development of inflammation. Because an increase of the residual MK activity is expected to make MKD-HIDS patients less sensitive to developing inflammatory episodes, we established a cell-based screen that can be used to identify compounds and/or therapeutic targets that promote this increase. Using a reporter HeLa cell line that stably expresses the most common MKD-HIDS variant, MK-V377I, C-terminally tagged with bioluminescent NanoLuc luciferase (nLuc), we screened the Prestwick Chemical Library®, which includes 1280 FDA-approved compounds. Multiple compounds increased MK-V377I-nLuc bioluminescence, including steroids (i.e., glucocorticoids, estrogens, and progestogens), statins and antineoplastic drugs. The glucocorticoids increased MK-V377I-nLuc bioluminescence through glucocorticoid receptor signaling. Subsequent studies in MKD-HIDS patient cells showed that the potent glucocorticoid clobetasol propionate increases gene transcription of MVK and other genes regulated by the transcription factor sterol regulatory element-binding protein 2 (SREBP-2). Our results suggest that increasing the flux through the isoprenoid biosynthesis pathway by targeting the glucocorticoid receptor or SREBP-2 could be a potential therapeutic strategy in MKD-HIDS.

Dexamethasone Inhibits White Adipose Tissue Browning

White adipose tissue (WAT) regulates energy balance through energy storage, adipokines secretion and the thermogenesis process. Beige adipocytes are responsible for WAT thermogenesis. They are generated by adipogenesis or transdifferentiation during cold or β3-adrenergic agonist stimulus through a process called browning. Browning has gained significant interest for to its preventive effect on obesity. Glucocorticoids (GCs) have several functions in WAT biology; however, their role in beige adipocyte generation and WAT browning is not fully understood. The aim of our study was to determine the effect of dexamethasone (DXM) on WAT thermogenesis. For this purpose, rats were treated with DXM at room temperature (RT) or cold conditions to determine different thermogenic markers. Furthermore, the effects of DXM on the adipogenic potential of beige precursors and on mature beige adipocytes were evaluated in vitro. Our results showed that DXM decreased UCP-1 mRNA and protein levels, mainly after cold exposure. In vitro studies showed that DXM decreased the expression of a beige precursor marker (Ebf2), affecting their ability to differentiate into beige adipocytes, and inhibited the thermogenic response of mature beige adipocytes (Ucp-1, Dio2 and Pgc1α gene expressions and mitochondrial respiration). Overall, our data strongly suggest that DXM can inhibit the thermogenic program of both retroperitoneal and inguinal WAT depots, an effect that could be exerted, at least partially, by inhibiting de novo cell generation and the thermogenic response in beige adipocytes.

Biased regulation of glucocorticoid receptors signaling

Glucocorticoids (GCs), steroid hormones that depend on glucocorticoid receptor (GR) binding for their action, are essential for regulating numerous homeostatic functions in the body.GR signals are biased, that is, GR signals are various in different tissue cells, disease states and ligands. This biased regulation of GR signaling appears to depend on ligand-induced metameric regulation, protein post-translational modifications, assembly at response elements, context-specific assembly (recruitment of co-regulators) and intercellular differences. Based on the bias regulation of GR, selective GR agonists and modulators (SEGRAMs) were developed to bias therapeutic outcomes toward expected outcomes (e.g., anti-inflammation and immunoregulation) by influencing GR-mediated gene expression. This paper provides a review of the bias regulation and mechanism of GR and the research progress of drugs.

Oral mometasone furoate administration preserves anti-inflammatory action with fewer metabolic adverse effects in rats

BACKGROUND

Exogenous glucocorticoids (CGs) possess relevant therapeutic effects but exert diabetogenic actions when in excess. Thus, ligands with potential therapeutic applications and fewer adverse effects are needed. To this, we analyzed whether mometasone furoate (MF), a CG expected to cause fewer side effects, given through systemic routes, could maintain the anti-inflammatory actions without relevant repercussions on metabolism.

METHODS

The anti-inflammatory effect of MF was evaluated with both peritonitis and colitis models in rodents. Glucose and lipid metabolism were investigated in male and female rats treated daily with MF with different doses and routes of administration for seven days. The involvement of glucocorticoid receptor (GR) on MF actions was assessed in animals pretreated with mifepristone. Also, the potential reversibility of the adverse effects was assessed. Dexamethasone was used as a positive control.

RESULTS

MF treatment resulted in glucose intolerance in male rats treated through intraperitoneal (ip) but not oral gavage route (og). In female rats, none of the routes led to glucose intolerance. MF treatment attenuated insulin sensitivity and increased pancreatic β-cell mass, regardless of the sex and route of administration. MF treatment through og route did not result in dyslipidemia, as observed in rats treated through the ip route (both sexes). The anti-inflammatory and metabolic adverse effects of MF were GR-dependent, and metabolic outcomes altered by MF administration were reversible.

CONCLUSION

MF maintains anti-inflammatory activity when administered by systemic routes and exerts less impact on metabolism when administered orally in male and female rats, effects that are GR-dependent and reversible. Category: Metabolic Disorders and Endocrinology.

A plant-derived glucocorticoid receptor modulator with potency to attenuate the side effects of glucocorticoid therapy

BACKGROUND AND PURPOSE

Continuous efforts have been made to move towards maintaining the beneficial anti-inflammatory functions of glucocorticoids (GCs) while minimizing side effects. Here, we investigated the selective glucocorticoid receptor (GR) modulator-like properties of a plant-derived compound caesaldekarin e (CA-e).

EXPERIMENTAL APPROACH

The therapeutic efficacy of CA-e was evaluated in several mouse models, including dextran sulfate sodium-induced colitis, ovalbumin-induced lung allergic inflammation, imiquimod-induced psoriasis-like skin inflammation and skin atrophy. The action of CA-e targeting the GR was analysed using molecular docking, cellular thermal shift assays and microscale thermophoresis. Other methods included DNA-protein pull-down assays and mass spectrometry.

KEY RESULTS

CA-e selectively inhibited positive GC response element ((+) GRE)-mediated direct transactivation while maintaining and even enhancing the anti-inflammatory effects of treatment with dexamethasone. CA-e, alone and in combination with dexamethasone, efficiently alleviated inflammation in several mouse models with milder side effects compared with dexamethasone alone. Mechanistically, CA-e inhibited the formation of dimers by binding to the dimerization interface located in the ligand-binding domain of GR and facilitated embryonic ectoderm development that is involved in the regulation of transcriptional repression to compete for binding to (+) GRE, eventually leading to the repression of (+) GRE-regulated genes. In addition, CA-e repressed NF-κB-dependent genes by enhancing the interaction between GR and p65.

CONCLUSIONS AND IMPLICATIONS

Our results reveal that CA-e is a novel GR modulator with strong potency to attenuate the side effects of GC therapy and can be used as a potential molecular tool for deciphering GR signalling.

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.

Point mutation I634A in the glucocorticoid receptor causes embryonic lethality by reduced ligand binding

The glucocorticoid (GC) receptor (GR) is essential for normal development and in the initiation of inflammation. Healthy GR^dim/dim mice with reduced dimerization propensity due to a point mutation (A465T) at the dimer interface of the GR DNA-binding domain (DBD) (here GR^D/D) have previously helped to define the functions of GR monomers and dimers. Since GR^D/D retains residual dimerization capacity, here we generated the dimer-nullifying double mutant GR^D+L/D+L mice, featuring an additional mutation (I634A) in the ligand-binding domain (LBD) of GR. These mice are perinatally lethal, as are GR^L/L mice (these mice have the I634A mutation but not the A465T mutation), displaying improper lung and skin formation. Using embryonic fibroblasts, high and low doses of dexamethasone (Dex), nuclear translocation assays, RNAseq, dimerization assays, and ligand-binding assays (and K_d values), we found that the lethal phenotype in these mice is due to insufficient ligand binding. These data suggest there is some correlation between GR dimerization potential and ligand affinity. We conclude that even a mutation as subtle as I634A, at a position not directly involved in ligand interactions sensu stricto, can still influence ligand binding and have a lethal outcome.

Discovery of Novel GR Ligands toward Druggable GR Antagonist Conformations Identified by MD Simulations and Markov State Model Analysis

Binding of different ligands to glucocorticoid receptor (GR) may induce different conformational changes and even trigger completely opposite biological functions. To understand the allosteric communication within the GR ligand binding domain, the folding pathway of helix 12 (H12) induced by the binding of the agonist dexamethasone (DEX), antagonist RU486, and modulator AZD9567 are explored by molecular dynamics simulations and Markov state model analysis. The ligands can regulate the volume of the activation function-2 through the residues Phe737 and Gln738. Without ligand or with agonist binding, H12 swings from inward to outward to visit different folding positions. However, the binding of RU486 or AZD9567 perturbs the structural state, and the passive antagonist state appears more stable. Structure-based virtual screening and in vitro bioassays are used to discover novel GR ligands that bias the conformation equilibria toward the passive antagonist state. HP-19 exhibits the best anti-inflammatory activity (IC50 = 0.041 ± 0.011 µm) in nuclear factor-kappa B signaling pathway, which is comparable to that of DEX. HP-19 also does not induce adverse effect-related transactivation functions of GR. The novel ligands discovered here may serve as promising starting points for the development of GR modulators.

Multi-Component One-Pot Assisted Synthesis, Anti-bacterial Capabilities, and Scanning Electron Microscopy of Novel Corticosteroid Thiopyran

BACKGROUND

Corticosteroids are an important group of polycyclic compounds having a wide range of pharmacological and physiological properties. Thiopyran derivatives are important building blocks of many biologically active compounds.

OBJECTIVE

Keeping in mind the wide range of applications of corticosteroids and thiopyran, herein we intend to develop a simple and efficient strategy to synthesize steroidal thiopyran derivatives starting with different commercially available corticosteroids and study their biological properties.

MATERIALS AND METHODS

To achieve our aim, we employed a one-pot multi-component synthesis of steroidal thiopyran derivatives by the reaction of corticosteroids, malononitrile, and carbon disulphide in the presence of triethylamine as a catalyst.

RESULTS AND DISCUSSION

An array of novel thiopyran compounds was obtained with the highest product yield using Et₃N. Scanning electron microscopy analysis manifested agglomeration pertaining to brick-shaped crystals of corticosteroid thiopyran. Synthesized compounds were also found to be active as anti-bacterial agents.

CONCLUSION

We describe a facile one-pot multi-component synthesis of corticosteroid thiopyran derivatives, which are found to possess anti-bacterial activity. Excellent yields of the products, simple work-up, easily available starting materials, and non-chromatographic purification are some of the main advantages of this protocol.

Views on glucocorticoid therapy in rheumatology: the age of convergence

After decades of sometimes fierce debate about the advantages and disadvantages of glucocorticoids, an age of convergence has been reached. Current recommendations for the management of diseases such as rheumatoid arthritis (RA), polymyalgia rheumatica and large vessel vasculitis reflect the current consensus that as much glucocorticoid as necessary, but as little as possible, should be used. Over the past few years, a range of glucocorticoid-sparing strategies have been developed, as have tools to improve the management of this therapy. A comprehensive view of glucocorticoid-induced osteoporosis has also emerged that recognizes that bone fragility is not solely determined by the dose and duration of glucocorticoid treatment. Nevertheless, open questions remain around whether long-term use of very low doses of glucocorticoids is a realistic option for patients with RA and whether the search for innovative glucocorticoids or glucocorticoid receptor ligands with improved benefit-to-risk ratios will ultimately be successful.

GR Dimerization and the Impact of GR Dimerization on GR Protein Stability and Half-Life

Pharmacologically, glucocorticoids, which mediate their effects via the glucocorticoid receptor (GR), are a most effective therapy for inflammatory diseases despite the fact that chronic use causes side-effects and acquired GC resistance. The design of drugs with fewer side-effects and less potential for the development of resistance is therefore considered crucial for improved therapy. Dimerization of the GR is an integral step in glucocorticoid signaling and has been identified as a possible molecular site to target for drug development of anti-inflammatory drugs with an improved therapeutic index. Most of the current understanding regarding the role of GR dimerization in GC signaling derives for dimerization deficient mutants, although the role of ligands biased toward monomerization has also been described. Even though designing for loss of dimerization has mostly been applied for reduction of side-effect profile, designing for loss of dimerization may also be a fruitful strategy for the development of GC drugs with less potential to develop GC resistance. GC-induced resistance affects up to 30% of users and is due to a reduction in the GR functional pool. Several molecular mechanisms of GC-mediated reductions in GR pool have been described, one of which is the autologous down-regulation of GR density by the ubiquitin-proteasome-system (UPS). Loss of GR dimerization prevents autologous down-regulation of the receptor through modulation of interactions with components of the UPS and post-translational modifications (PTMs), such as phosphorylation, which prime the GR for degradation. Rational design of conformationally biased ligands that select for a monomeric GR conformation, which increases GC sensitivity through improving GR protein stability and increasing half-life, may be a productive avenue to explore. However, potential drawbacks to this approach should be considered as well as the advantages and disadvantages in chronic vs. acute treatment regimes.

A General Introduction to Glucocorticoid Biology

Glucocorticoids (GCs) are steroid hormones widely used for the treatment of inflammation, autoimmune diseases, and cancer. To exert their broad physiological and therapeutic effects, GCs bind to the GC receptor (GR) which belongs to the nuclear receptor superfamily of transcription factors. Despite their success, GCs are hindered by the occurrence of side effects and glucocorticoid resistance (GCR). Increased knowledge on GC and GR biology together with a better understanding of the molecular mechanisms underlying the GC side effects and GCR are necessary for improved GC therapy development. We here provide a general overview on the current insights in GC biology with a focus on GC synthesis, regulation and physiology, role in inflammation inhibition, and on GR function and plasticity. Furthermore, novel and selective therapeutic strategies are proposed based on recently recognized distinct molecular mechanisms of the GR. We will explain the SEDIGRAM concept, which was launched based on our research results.

Liposomal dexamethasone inhibits tumor growth in an advanced human-mouse hybrid model of multiple myeloma

Glucocorticoids are the cornerstone in the clinic for treatment of hematological malignancies, including multiple myeloma. Nevertheless, poor pharmacokinetic properties of glucocorticoids require high and frequent dosing with the off-target adverse effects defining the maximum dose. Recently, nanomedicine formulations of glucocorticoids have been developed that improve the pharmacokinetic profile, limit adverse effects and improve solid tumor accumulation. Multiple myeloma is a hematological malignancy characterized by uncontrolled growth of plasma cells. These tumors initiate increased angiogenesis and microvessel density in the bone marrow, which might be exploited using nanomedicines, such as liposomes. Nano-sized particles can accumulate as a result of the increased vascular leakiness at the bone marrow tumor lesions. Pre-clinical screening of novel anti-myeloma therapeutics in vivo requires a suitable animal model that represents key features of the disease. In this study, we show that fluorescently labeled long circulating liposomes were found in plasma up to 24 h after injection in an advanced human-mouse hybrid model of multiple myeloma. Besides the organs involved in clearance, liposomes were also found to accumulate in tumor bearing human-bone scaffolds. The therapeutic efficacy of liposomal dexamethasone phosphate was evaluated in this model showing strong tumor growth inhibition while free drug being ineffective at an equivalent dose (4 mg/kg) regimen. The liposomal formulation slightly reduced total body weight of myeloma-bearing mice during the course of treatment, which appeared reversible when treatment was stopped. Liposomal dexamethasone could be further developed as monotherapy or could fit in with existing therapy regimens to improve therapeutic outcomes for multiple myeloma.

Early Targeted Combination Treatment With Conventional Synthetic Disease-Modifying Antirheumatic Drugs and Long-Term Outcomes in Rheumatoid Arthritis: Ten-Year Follow-Up Results of a Randomized Clinical Trial

OBJECTIVE

The short-term outcomes of remission-targeted treatments of rheumatoid arthritis (RA) are well-established, but the long-term success of such strategies is speculative, as is the role of early add-on biologics. We assessed the 10-year outcomes of patients with early RA treated with initial remission-targeted triple combination of conventional synthetic disease-modifying antirheumatic drugs (csDMARDs), 7.5-mg prednisolone, and additional infliximab (IFX) or placebo infusions.

METHODS

Ninety-nine patients with early, DMARD-naive RA were treated with a triple combination of csDMARDs and prednisolone and randomized to double-blind receipt of infusions of either IFX (the Finnish Rheumatoid Arthritis Combination Therapy Trial [FIN-RACo] + IFX) or placebo (FIN-RACo + placebo) during the first 6 months. After 2 years, the treatment strategies became unrestricted, but the treatment goal was strict remission in the TNF-Blocking Therapy in Combination With Disease-Modifying Antirheumatic Drugs in Early Rheumatoid Arthritis (NEO-RACo) study. At 10 years, the clinical and radiographic outcomes and the drug treatments used between 5 and 10 years were assessed.

RESULTS

Ninety patients (91%) were followed after 2 years, 43 in the FIN-RACo + IFX and 47 in the FIN-RACo + placebo group. At 10 years, the respective proportions of patients in strict NEO-RACo remission and in Disease Activity Score using 28 joints remission in the FIN-RACo + IFX and FIN-RACo + placebo groups were 46% and 38% (P = 0.46) and 82% and 72% (P = 0.29), respectively. The mean total Sharp/van der Heijde score was 9.8 in the FIN-RACo + IFX and 7.3 in the FIN-RACo + placebo group (P = 0.34). During the 10-year follow-up, 26% of the FIN-RACo + IFX group and 30% of the FIN-RACo + placebo group had received biologics (P = 0.74).

CONCLUSION

In early RA, excellent results can be maintained up until 10 years in most patients treated with initial combination csDMARDs and remission-targeted strategy, regardless of initial IFX/placebo infusions.

A screening assay for Selective Dimerizing Glucocorticoid Receptor Agonists and Modulators (SEDIGRAM) that are effective against acute inflammation

It has been suggested that glucocorticoid receptor (GR) agonists that promote GR homodimerization more than standard glucocorticoids such as Dexamethasone could be more effective anti-inflammatory molecules against acute and life-threatening inflammatory conditions. To test this hypothesis, we set up a screening pipeline aimed at discovering such Selective Dimerizing GR Agonists and Modulators (SEDIGRAM). The pipeline consists of a reporter gene assay based on a palindromic glucocorticoid responsive element (GRE). This assay represents GR dimerization in human A549 lung epithelial cells. In the pipeline, this is followed by analysis of endogenous GRE-driven gene expression, a FRET assay confirming dimerization, and monitoring of in vitro and in vivo anti-inflammatory activity. In a proof of principle experiment, starting from seven candidate compounds, we identified two potentially interesting compounds (Cortivazol and AZD2906) that confer strong protection in a mouse model of aggressive TNF-induced lethal inflammation. A screening pipeline for SEDIGRAM may assist the search for compounds that promote GR dimerization and limit overwhelming acute inflammatory responses.

Discovery of a Novel Oral Glucocorticoid Receptor Modulator (AZD9567) with Improved Side Effect Profile

Synthetic glucocorticoids (GC) are essential for the treatment of a broad range of inflammatory diseases. However, their use is limited by target related adverse effects on, e.g., glucose homeostasis and bone metabolism. Starting from a nonsteroidal GR ligand (4) that is a full agonist in reporter gene assays, we exploited key functional triggers within the receptor, generating a range of structurally diverse partial agonists. Of these, only a narrow subset exhibited full anti-inflammatory efficacy and a significantly reduced impact on adverse effect markers in human cell assays compared to prednisolone. This led to the discovery of AZD9567 (15) with excellent in vivo efficacy when dosed orally in a rat model of joint inflammation. Compound 15 is currently being evaluated in clinical trials comparing the efficacy and side effect markers with those of prednisolone.

Efficacy and safety of selective glucocorticoid receptor modulators in comparison to glucocorticoids in arthritis, a systematic review

Background

Long-term treatment with glucocorticoids (GCs) plays an important role in the management of arthritis patients, although the efficacy/safety balance is unfavorable. Alternatives with less (severe) adverse effects but with good efficacy are needed. Selective GC receptor modulators (SGRMs) are designed to engage the GC receptor with dissociative characteristics: transactivation of genes, which is mainly responsible for unwanted effects, is less strong while trans-repression of genes, reducing inflammation, is maintained. It is expected that SGRMs thus have a better efficacy/safety balance than GCs. A systematic review providing an overview of the evidence in arthritis is lacking.

Objective

To systematically review the current literature on efficacy and safety of oral SGRMs in comparison to GCs in arthritis.

Methods

A search was performed in Medline, Embase and the Cochrane Library, from inception dates of databases until May 2017. Experimental studies involving animal arthritis models or human material of arthritis patients, as well as clinical studies in arthritis patients were included, provided they reported original data. All types of arthritis were included. Data was extracted on the SGRM studied and on the GC used as reference standard; the design or setting of the study was extracted as well as the efficacy and safety results.

Results

A total of 207 articles was retrieved of which 17 articles were eligible for our analysis. Two studies concerned randomized controlled trials (RCT), five studies were pre-clinical studies using human material, and 10 studies involved pre-clinical animal models (acute and/or chronic arthritis induced in mice or rats). PF-04171327, the only compound investigated in a clinical trial setting, had a better efficacy/safety balance compared to GCs: better clinical anti-inflammatory efficacy and similar safety.

Conclusion

Studies assessing both efficacy and safety of SGRMs are scarce. There is limited evidence for dissociation of anti-inflammatory and metabolic effects of the SGRMs studied. Development of many SGRMs is haltered in a preclinical phase. One SGRM showed a better clinical efficacy/safety balance.