Glucocorticoid Receptor Agonist Research Articles

How the Xenopus eleutheroembryonic thyroid assay compares to the amphibian metamorphosis assay for detecting thyroid active chemicals

The Xenopus Eleutheroembryonic Thyroid Assay (XETA) was recently published as an OECD Test Guideline for detecting chemicals acting on the thyroid axis. However, the OECD validation did not cover all mechanisms that can potentially be detected by the XETA. This study was therefore initiated to investigate and consolidate the applicability domain of the XETA regarding the following mechanisms: thyroid hormone receptor (THR) agonism, sodium-iodide symporter (NIS) inhibition, thyroperoxidase (TPO) inhibition, deiodinase (DIO) inhibition, glucocorticoid receptor (GR) agonism, and uridine 5′-diphospho-glucuronosyltransferase (UDPGT) induction. In total, 22 chemicals identified as thyroid-active or -inactive in Amphibian Metamorphosis Assays (AMAs) were tested using the XETA OECD Test Guideline. The comparison showed that both assays are highly concordant in identifying chemicals with mechanisms of action related to THR agonism, DIO inhibition, and GR agonism. They also consistently identified the UDPGT inducers as thyroid inactive. NIS inhibition, investigated using sodium perchlorate, was not detected in the XETA. TPO inhibition requires further mechanistic investigations as the reference chemicals tested resulted in opposing response directions in the XETA and AMA. This study contributes refining the applicability domain of the XETA, thereby helping to clarify the conditions where it can be used as an ethical alternative to the AMA.

Effect of ACEA 1021 on Neurotoxicity Induced by Dexamethasone — Initial Behavioral Study

Considerable evidence suggests that glucocorticoids (GCs) play an important role in neurodegeneration. Chronic elevated levels of GCs can result in neuronal degeneration of the hippocampal piramidal neurons, which are paralleled by cognitive deficits. Moreover, GCs potentiate stress or ischemia-induced accumulation of excitatory amino acids (EAA) in the extracellular space of hippocampus. ACEA 1021 (licostinel), a selective antagonist of the N-methyl-D-aspartate (NMDA) receptor, has been reported to prevent the excitotoxic action of high extracellular glutamate levels. The aim of this study was to investigate the effect of ACEA 1021 on neurotoxic effect of dexamethasone (DEX - a synthetic GCs receptor agonist). The experiments were carried out on Albino Swiss mice (25-30 g). ACEA 1021, at the doses: 1.25 and 2.5 mg/kg/day, ip, was administered 15 min before DEX (16 mg/kg/day, ip). The long-term memory acquisition (passive avoidance test) and the motor performance (“chimney” test) were evaluated 14 days after the drugs administration. The prolongation of climbing time in the “chimney” test and decrease of the retention time in the memory task of mice treated with DEX for 14 days. In mice treated with DEX for 14 days, ACEA 1021 at the both doses reduced the climbing time in the “chimney” test, at the dose of 1.25 mg/kg improved memory acquisition. The above findings suggest that ACEA 1021 could prevent the neurotoxic effects induced by DEX, but further study needs to be carried out to explain this effect.

Abstract 1691: p300 catalytic inhibition selectively targets IRF4 oncogenic activity in multiple myeloma

Abstract Multiple myeloma (MM), an incurable plasma cell malignancy, is addicted to oncogenic transcription factor (TF) IRF4 signaling. Lineage TFs like IRF4 are difficult to drug but represent high value oncology targets owing to the depth and context selectivity of their genetic dependency. Using a transcription regulatory network (TRN) based approach to integrate a high dimensional multi-platform dataset, we defined the key regulatory activity of IRF4 and its druggable co-factors. This unbiased analysis identified p300 lysine acetyl transferase (KAT) function as the nearest selective neighbor for therapeutic intervention, with more potent and selective effects than historically observed with p300/CBP bromodomain inhibitors. To further probe this biology, we developed a highly selective inhibitor of the KAT domain of p300 and its close homolog CBP. p300 KAT inhibition led to selective downregulation of IRF4 at the mRNA and protein level as well as reduction in acetylation at highly specific sites co-localized with IRF4, in contrast to more general agents like BET inhibitors. Gene expression reduction was most pronounced at IRF4/p300 co-bound genes, in particular IRF4 itself and MYC. IRF4 and p300 also directly bind to each other and other key MM nodes regulating them at the chromatin, mRNA, and protein levels. p300 KAT inhibition exhibits strong antiproliferative activity across in vitro MM models regardless of cytogenetics or resistance to other therapies. Moreover, this relationship is mediated by the KAT domain and not its acetyl-lysine recognizing bromodomain. Comparative pharmacology studies found that a p300 KAT inhibitor downregulated the IRF4 TRN and induced apoptosis in MM cells more effectively than existing standard of care agents, including IMiDs and glucocorticoid receptor agonists, or p300/CBP bromodomain inhibitors. Combinations of a p300 KAT inhibitor with clinically active molecules such as IMiDs and glucocorticoid agonists showed synergistic impacts on reducing key MM TFs and cell line viability. Ex vivo treatment of primary patient samples demonstrated broad anti-proliferative activity with loss of IRF4 and induction of apoptosis in relapsed-refractory MM patient samples, independent of prior lines of therapy. Importantly, the induction of MM cell apoptosis occurs in the milieu of CD138 negative bone marrow stromal cells while also sparing them from toxicity, supporting a potential therapeutic index. Finally, p300 KAT inhibition demonstrated activity in in vivo MM models with robust tumor growth inhibition at tolerated doses and exposures correlated to reduced p300-dependent substrate acetylation. IRF4 dependency is a hallmark of MM that has been challenging to target with existing therapies, motivating further development of p300 KAT targeting therapeutics. Citation Format: Michael R. McKeown, Giulia Giorgetti, Walter F. Lenoir, Marek J. Kobylarz, Tamara D. Hopkins, Wayne L. Glore, Michelle G. Shum, Yare Calderon, Kameron R. Mori, Hua Gao, Luis A. Carvajal, Nikolaus D. Obholzer, Benjamin W. Trotter, Christopher D. Dinsmore, Nikhil C. Munshi, Peter B. Rahl, Mariateresa Fulciniti, Charles Y. Lin. p300 catalytic inhibition selectively targets IRF4 oncogenic activity in multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1691.

Abstract 3490: Unveiling sex differences in lung adenocarcinoma through multi-omics integrative protein signaling networks

Abstract Sex differences in lung adenocarcinoma (LUAD) are evident in incidence rates, prognostic outcomes, and therapy responses, yet the underlying molecular mechanisms driving these disparities remain underexplored. In this study, we conducted a comprehensive proteogenomic analysis encompassing 38 females and 73 males with LUAD from the Clinical Proteomic Tumor Analysis Consortium (CPTAC) dataset. Employing Transcription Inference using Gene Expression and Regulatory data (TIGER), we inferred sex-differentially activated transcription factors (TFs) from The Cancer Genome Atlas (TCGA) LUAD gene expression data and identified sex-differentially activated kinases using CPTAC protein phosphorylation data. We further constructed a comprehensive kinase-TF signaling network by integrating these sex-differentially activated kinases with TFs, identifying all paths shorter than 3 in the protein interaction networks to highlight druggable pathways. Our analyses revealed that many proteins exhibit not only sex-biased abundance but also sex-biased phosphorylation and acetylation. Furthermore, these sex-biased proteins were associated with critical biological pathways including cell proliferation, immune response, and metabolism. Using kinase-TF signaling networks, we found substantial sex bias in the activities of clinically actionable TFs and kinases, including the glucocorticoid receptor (NR3C1), AR, AURKA, CDK6, and MAPK14. Leveraging the PRISM cancer cell line screening database, we identified several small-molecule drugs, such as glucocorticoid receptor agonists and aurora kinase inhibitors, potentially exhibiting sex-specific efficacy as LUAD therapeutics. Our findings showed that the activity of some clinically relevant TFs and kinases differ by sex in LUAD, underscoring the need to consider sex as a biological variable and the utility of multi-omics integrative protein signaling networks in advancing our understanding of cancer biology and the development of sex-aware therapeutics. Citation Format: Chen Chen, Enakshi Saha, Dawn L. DeMeo, John Quackenbush, Camila M. Lopes-Ramos. Unveiling sex differences in lung adenocarcinoma through multi-omics integrative protein signaling networks [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3490.

Selective Modulation of the Human Glucocorticoid Receptor Compromises GR Chromatin Occupancy and Recruitment of p300/CBP and the Mediator Complex

Exogenous glucocorticoids are frequently used to treat inflammatory disorders and as adjuncts for the treatment of solid cancers. However, their use is associated with severe side effects and therapy resistance. Novel glucocorticoid receptor (GR) ligands with a patient-validated reduced side effect profile have not yet reached the clinic. GR is a member of the nuclear receptor family of transcription factors and heavily relies on interactions with coregulator proteins for its transcriptional activity. To elucidate the role of the GR interactome in the differential transcriptional activity of GR following treatment with the selective GR agonist and modulator dagrocorat compared to classic (ant)agonists, we generated comprehensive interactome maps by high-confidence proximity proteomics in lung epithelial carcinoma cells. We found that dagrocorat and the antagonist RU486 both reduced GR interaction with CREB-binding protein/p300 and the mediator complex compared to the full GR agonist dexamethasone. Chromatin immunoprecipitation assays revealed that these changes in GR interactome were accompanied by reduced GR chromatin occupancy with dagrocorat and RU486. Our data offer new insights into the role of differential coregulator recruitment in shaping ligand-specific GR-mediated transcriptional responses.

Differential susceptibility of male and female germ cells to glucocorticoid-mediated signaling

While physiologic stress has long been known to impair mammalian reproductive capacity through hormonal dysregulation, mounting evidence now suggests that stress experienced prior to or during gestation may also negatively impact the health of future offspring. Rodent models of gestational physiologic stress can induce neurologic and behavioral changes that persist for up to three generations, suggesting that stress signals can induce lasting epigenetic changes in the germline. Treatment with glucocorticoid stress hormones is sufficient to recapitulate the transgenerational changes seen in physiologic stress models. These hormones are known to bind and activate the glucocorticoid receptor (GR), a ligand-inducible transcription factor, thus implicating GR-mediated signaling as a potential contributor to the transgenerational inheritance of stress-induced phenotypes. Here, we demonstrate dynamic spatiotemporal regulation of GR expression in the mouse germline, showing expression in the fetal oocyte as well as the perinatal and adult spermatogonia. Functionally, we find that fetal oocytes are intrinsically buffered against changes in GR signaling, as neither genetic deletion of GR nor GR agonism with dexamethasone altered the transcriptional landscape or the progression of fetal oocytes through meiosis. In contrast, our studies revealed that the male germline is susceptible to glucocorticoid-mediated signaling, specifically by regulating RNA splicing within the spermatogonia, although this does not abrogate fertility. Together, our work suggests a sexually dimorphic function for GR in the germline, and represents an important step towards understanding the mechanisms by which stress can modulate the transmission of genetic information through the germline.

Differential susceptibility of male and female germ cells to glucocorticoid-mediated signaling.

While physiologic stress has long been known to impair mammalian reproductive capacity through hormonal dysregulation, mounting evidence now suggests that stress experienced prior to or during gestation may also negatively impact the health of future offspring. Rodent models of gestational physiologic stress can induce neurologic and behavioral changes that persist for up to three generations, suggesting that stress signals can induce lasting epigenetic changes in the germline. Treatment with glucocorticoid stress hormones is sufficient to recapitulate the transgenerational changes seen in physiologic stress models. These hormones are known to bind and activate the glucocorticoid receptor (GR), a ligand-inducible transcription factor, thus implicating GR-mediated signaling as a potential contributor to the transgenerational inheritance of stress-induced phenotypes. Here, we demonstrate dynamic spatiotemporal regulation of GR expression in the mouse germline, showing expression in the fetal oocyte as well as the perinatal and adult spermatogonia. Functionally, we find that fetal oocytes are intrinsically buffered against changes in GR signaling, as neither genetic deletion of GR nor GR agonism with dexamethasone altered the transcriptional landscape or the progression of fetal oocytes through meiosis. In contrast, our studies revealed that the male germline is susceptible to glucocorticoid-mediated signaling, specifically by regulating RNA splicing within the spermatogonia, although this does not abrogate fertility. Together, our work suggests a sexually dimorphic function for GR in the germline, and represents an important step towards understanding the mechanisms by which stress can modulate the transmission of genetic information through the germline.

Comparison of the Glucocorticoid Receptor Binding and Agonist Activities of Typical Glucocorticoids: Insights into Their Endocrine Disrupting Effects.

Over the past decades, the synthetic glucocorticoids (GCs) have been widely used in clinical practice and animal husbandry. Given the health hazard of these toxic residues in food, it is necessary to explore the detailed interaction mechanisms of typical GCs and their main target glucocorticoid receptor (GR). Hence, this work compared the GR binding and agonist activities of typical GCs. Fluorescence polarization assay showed that these GCs were potent ligands of GR. Their GR binding affinities were in the order of methylprednisolone>betamethasone≈prednisolone>dexamethasone, with IC50 values of 1.67, 2.94, 2.95, and 5.58 nM. Additionally, the limits of detection of dexamethasone, betamethasone, prednisolone, and methylprednisolone were 0.32, 0.14, 0.19, and 0.09 μg/kg in fluorescence polarization assay. Reporter gene assay showed that these GCs induced GR transactivation in a dose-dependent manner, confirming their GR agonist activities. Among which, dexamethasone at the concentration of 100 nM produced a maximal induction of more than 11-fold over the blank control. Molecular docking and molecular dynamics simulations suggested that hydrogen-bonding and hydrophobic interactions played an important role in stabilizing the GC-GR-LBD complexes. In summary, this work might help to understand the GR-mediated endocrine disrupting effects of typical GCs.

Skin Anti-Inflammatory Potential with Reduced Side Effects of Novel Glucocorticoid Receptor Agonists.

Glucocorticoids (GCs) are commonly used in the treatment of inflammatory skin diseases, although the balance between therapeutic benefits and side effects is still crucial in clinical practice. One of the major and well-known adverse effects of topical GCs is cutaneous atrophy, which seems to be related to the activation of the glucorticoid receptor (GR) genomic pathway. Dissociating anti-inflammatory activity from atrophogenicity represents an important goal to achieve, in order to avoid side effects on keratinocytes and fibroblasts, known target cells of GC action. To this end, we evaluated the biological activity and safety profile of two novel chemical compounds, DE.303 and KL.202, developed as non-transcriptionally acting GR ligands. In primary keratinocytes, both compounds demonstrated anti-inflammatory properties inhibiting NF-κB activity, downregulating inflammatory cytokine release and interfering with pivotal signaling pathways involved in the inflammatory process. Of note, these beneficial actions were not associated with GC-related atrophic effects: treatments of primary keratinocytes and fibroblasts with DE.303 and KL.202 did not induce, contrarily to dexamethasone-a known potent GC-alterations in extracellular matrix components and lipid synthesis, thus confirming their safety profile. These data provide the basis for evaluating these compounds as effective alternatives to the currently used GCs in managing inflammatory skin diseases.

Synephrine and Its Derivative Compound A: Common and Specific Biological Effects.

This review is focused on synephrine, the principal phytochemical found in bitter orange and other medicinal plants and widely used as a dietary supplement for weight loss/body fat reduction. We examine different aspects of synephrine biology, delving into its established and potential molecular targets, as well as its mechanisms of action. We present an overview of the origin, chemical composition, receptors, and pharmacological properties of synephrine, including its anti-inflammatory and anti-cancer activity in various in vitro and animal models. Additionally, we conduct a comparative analysis of the molecular targets and effects of synephrine with those of its metabolite, selective glucocorticoid receptor agonist (SEGRA) Compound A (CpdA), which shares a similar chemical structure with synephrine. SEGRAs, including CpdA, have been extensively studied as glucocorticoid receptor activators that have a better benefit/risk profile than glucocorticoids due to their reduced adverse effects. We discuss the potential of synephrine usage as a template for the synthesis of new generation of non-steroidal SEGRAs. The review also provides insights into the safe pharmacological profile of synephrine.

MOASL: Predicting drug mechanism of actions through similarity learning with transcriptomic signature

Understanding the mechanisms of actions (MOAs) of compounds is crucial in drug discovery. A common step in drug MOAs annotation is to query the dysregulated gene signatures induced by drugs in a reference library of pre-defined signatures. However, traditional similarity-based computational strategies face challenges when dealing with high-dimensional and noisy transcriptional signature data. To address this issue, we introduce MOASL (MOAs prediction via Similarity Learning), a novel approach that contrastive to learn similarity embeddings among signatures with shared MOAs automatically. We evaluated the accuracy of signature matching on various transcriptional activity score (TAS) datasets and individual cell lines by using MOASL. The results show MOASL achieved higher performance over several statistical and machine learning methods. Furthermore, we provided the rationale of our model by visualizing the signature annotation procedure. Using MOASL, the MOAs label of query signature could be conveniently defined by calculating the similarity between the query embedding and the reference embeddings. Finally, we applied MOASL to repurpose thousands of compounds as glucocorticoid receptor (GR) agonists, accurately identifying 8 out of the top 10 compounds. MOASL is conveniently accessible on GitHub at https://github.com/jianglikun/MOASL, empowering researchers and practitioners in the field of drug discovery to predict the MOAs of drug.

Comparative Assessment and High-Throughput Drug-Combination Profiling of TEAD-Palmitoylation Inhibitors in Hippo Pathway Deficient Mesothelioma.

The hippo signaling pathway is a central tumor suppressor cascade frequently inactivated in selected human cancers, leading to the aberrant activation of TEAD transcription factors. Whereas several TEAD auto-palmitoylation inhibitors are currently in development, a comprehensive assessment of this novel drug-modality is missing. Here, we report a comparative analysis among six TEADi(s) using cell-based and biochemical assays in Hippo pathway deficient mesothelioma. Our analysis revealed varying potency and selectivity across TEADi, also highlighting their limited efficacy. To overcome this limitation, we performed an unbiased, quantitative high-throughput drug screening by combining the TEADi VT-103 with a library of approximately 3000 oncology-focused drugs. By exploiting this library's mechanistic redundancy, we identified several drug-classes robustly synergized with TEADi. These included glucocorticoid-receptor (GR) agonists, Mek1/2 inhibitors, mTOR inhibitors, and PI3K inhibitors, among others. Altogether, we report a coherent single-agent dataset informing on potency and selectivity of TEAD-palmitoylation inhibitors as single-agents. We also describe a rational pipeline enabling the systematic identification of TEAD druggable co-dependencies. This data should support the pre-clinical development of drug combination strategies for the treatment of Hippo-deficient mesothelioma, and more broadly, for other cancers dependent on the oncogenic activity of YAP/TEAD.

Glucocorticoid Receptor Down-Regulation Affects Neural Stem Cell Proliferation and Hippocampal Neurogenesis.

Dysregulation of the hypothalamic-pituitary-adrenal axis and abnormalities in the glucocorticoid receptor (GR) have been linked to major depressive disorder. Given the critical role of GR in stress response regulation, we investigated the impact of GR changes on neural stem cells (NSCs) proliferation and hippocampal neurogenesis. Stress response was induced using dexamethasone (DEX), a GR agonist, which led to reduced proliferation of neural stem cells and neural progenitor cells, as well as decreased expression of GR. Additionally, a reduction of serum concentration within the culture media resulted in suppressed cell proliferation, accompanied by decreased GR expression. The association between GR expression and cell proliferation was further confirmed through GR siRNA knockdown and overexpression experiments. Furthermore, in vivo studies utilizing young male C57BL/6 mice demonstrated that corticosterone (CORT) (35μg/ml) administered through drinking water for four weeks induced depression-like behavior, as indicated by increased immobility times in forced swimming and tail suspension tests. CORT exposure led to reduced GR and nestin expression levels, along with diminished numbers of BrdU-positive cells in the hippocampi, indicating impaired hippocampal neurogenesis. Taken together, our findings provide the first evidence that stress-induced downregulation of GR negatively affects neurogenesis by inhibiting NSCs proliferation.

Impaired glucocorticoid receptor function attenuates herpes simplex virus 1 production during explant-induced reactivation from latency in female mice.

A correlation exists between stress and increased episodes of human alpha-herpes virus 1 reactivation from latency. Stress increases corticosteroid levels; consequently, the glucocorticoid receptor (GR) is activated. Recent studies concluded that a GR agonist, but not an antagonist, accelerates productive infection and reactivation from latency. Furthermore, GR and certain stress-induced transcription factors cooperatively transactivate promoters that drive the expression of infected cell protein 0 (ICP0), ICP4, and VP16. This study revealed female mice expressing a GR containing a serine to alanine mutation at position 229 (GRS229A) shed significantly lower levels of infectious virus during explant-induced reactivation compared to male GRS229A or wild-type parental C57BL/6 mice. Furthermore, female GRS229A mice contained fewer VP16 + TG neurons compared to male GRS229A mice or wild-type mice during the early stages of explant-induced reactivation from latency. Collectively, these studies revealed that GR transcriptional activity has female-specific effects, whereas male mice can compensate for the loss of GR transcriptional activation.

OR11-04 Activatable Glucocorticoid Receptor Agonists As Treatments For The Consequences Of Preterm Birth

Abstract Disclosure: R.S. Dhavan: None. K.L. Short: None. J. Ng: None. M.J. Wallace: None. P. Monaghan-Nichols: None. D. DeFranco: None. T.J. Cole: None. Glucocorticoid (GC) signaling is essential for normal fetal organ development. During late gestation a surge of endogenous GCs contributes to organ maturation, particularly important for the lung where thinning the mesenchymal tissue cause an increased alveolar-gas exchange surface area and decreased gas-exchange diffusion distance that is critical for lung function after birth. Currently potent synthetic GCs such as betamethasone (Bet) or dexamethasone (Dex) are administered antenatally to accelerate fetal lung maturation and reduce the risk of respiratory distress with preterm birth. There are however growing concerns that systemic exposure to powerful synthetic GCs such as Dex is associated with detrimental side effects, particularly in the developing fetal brain. We are currently assessing novel activatable and potentially partially selective agonists of the glucocorticoid receptor (GR) as new antenatal steroid treatments of preterm birth. One such GR agonist is a steroid prodrug called ciclesonide (Cic) that is activated in vivo to the GR agonist Des-Cic by a family of intracellular serine esterase enzymes, called carboxylesterases (Ces). We have previously demonstrated that postnatal administration of Cic and Dex drive similar stimulation of important preterm lung-specific biomarkers but in contrast to Dex, Cic produced no postnatal growth retardation, no reduction in brain weight, and no alteration in levels of neural myelination. In this current study we show by western blot analysis and immunofluorescence that the CES enzymes are expressed strongly in epithelial cells and the mesenchyme of peripheral organs such as the lung and kidney but are expressed at very low levels in the fetal and adult mouse brain, providing a basis for the preferential activation of Cic to Des-Cic only in peripheral organs. To examine the transcriptome changes induced by Cic vs Dex in the fetal mouse lung we have assessed cultured primary mouse fetal fibroblasts (the primary cell target for GCs during lung development) stimulated by 1μM Dex and Cic, for 6 hours. Changes in the fibroblast transcriptome was assessed by microarray analysis and relevant targets validated by real-time-qPCR. Analysis of the top 30 induced and repressed gene targets, including Fkbp5, Crispld2, Tgm2 and Zbtb16, demonstrated that Dex and Cic have almost identical activity profiles. Induction of transcriptional changes was completely lost in GR-null- derived fetal lung fibroblasts demonstrating specificity via the GR. The data suggests that Cic is able to regulate a respiratory genomic signature similar to Dex. Further studies will examine the effects of Cic vs Beta and Dex in mouse models of preterm birth, particularly in the context of unwanted side-effects in neural development. Presentation: Friday, June 16, 2023

EVALUATION AND STUDY OF PATHO-PHYSIOLOGICAL ROLE OF GLUCOCORTICOID RECEPTOR (GR) LIGANDS IN ACETAMINOPHEN-INDUCED LIVER INJURY IN MICE

Stress elicited by various drugs and psychosocial components is extensively prevalent globally. Glucocorticoid receptors control different features of lipid metabolism and lipoproteins in the liver. Acetaminophen or paracetamol is a broadly used antipyretic and analgesic drug. Overdose of acetaminophen causes centrilobular necrosis and fibrosis by generating oxidative stress. This experimental study was conducted to evaluate alone as well as combined systemic effects of glucocorticoid receptor (GR) ligands, Mifepristone (GR antagonist), and Dexamethasone (GR agonist) on oxidative damage and liver injury induced by acetaminophen. Evaluation of parameters of liver functions showed a substantial increase in AST ALT levels accompanied by elevation in TOS and reduction in TAC in the APAP-induced hepatotoxic group. While the groups that received dexamethasone, RU-486, and Dex+RU-486 as pretreatment significantly decreased the ALT, AST, and TOS levels compared to the toxic group (APAP). The protective effects of glucocorticoid receptor ligands in APAP-induced liver injury were further verified by histopathological examination. However, additional studies are necessary to illustrate the hepato-protective efficacy, safety profile, basic underlying process of protection, and therapeutic applications of glucocorticoid receptor ligands.

Self-Immolative Carbamate Linkers for CD19-Budesonide Antibody-Drug Conjugates.

Antibody-drug conjugates consist of potent small-molecule payloads linked to a targeting antibody. Payloads must possess a viable functional group by which a linker for conjugation can be attached. Linker-attachment options remain limited for the connection to payloads via hydroxyl groups. A releasing group based on 2-aminopyridine was developed to enable stable attachment of para-aminobenzyl carbamate (PABC) linkers to the C21-hydroxyl group of budesonide, a glucocorticoid receptor agonist. Payload release involves a cascade of two self-immolative events that are initiated by the protease-mediated cleavage of the dipeptide-PABC bond. Budesonide release rates were determined for a series of payload-linker intermediates in buffered solution at pH 7.4 and 5.4, leading to the identification of 2-aminopyridine as the preferred releasing group. Addition of a poly(ethylene glycol) group improved linker hydrophilicity, thereby providing CD19-budesonide ADCs with suitable properties. ADC23 demonstrated targeted delivery of budesonide to CD19-expressing cells and inhibited B-cell activation in mice.

Stress aggravates imiquimod-induced psoriasiform inflammation by promoting M1 macrophage polarization

Psychological stress has long been considered to cause the aggravation and recurrence of psoriasis, but the underlying mechanism remains largely unknown. Here, we used a mouse model of restraint-induced stress and imiquimod (IMQ)-induced psoriasiform inflammation to investigate the crosstalk between stress and the skin immune system and their functions in the pathogenesis of psoriasis. We found that stress aggravated skin inflammation and elevated serum corticosterone (CORT) levels in mice. Stress also increased the number of macrophages and glucocorticoid receptor (GR) expression in IMQ-treated mouse skin. GR agonist CORT upregulated the phosphorylation of STAT1 to promote M1 macrophage polarization in vitro. Additionally, GR deletion in macrophages and pharmacologic inhibition of GR improved skin inflammation and reduced M1 macrophage polarization under stress. Taken together, these results indicate that stress aggravates psoriasiform inflammation by promoting CORT/GR signaling-induced M1 macrophage polarization, suggesting that blocking the GR signaling has great potential as an adjuvant treatment for psoriasis patients with chronic stress.

Crosstalk between glucocorticoid and mineralocorticoid receptors boosts glucocorticoid-induced killing of multiple myeloma cells

The glucocorticoid receptor (GR) is a crucial drug target in multiple myeloma as its activation with glucocorticoids effectively triggers myeloma cell death. However, as high-dose glucocorticoids are also associated with deleterious side effects, novel approaches are urgently needed to improve GR action in myeloma. Here, we reveal a functional crosstalk between GR and the mineralocorticoid receptor (MR) that plays a role in improved myeloma cell killing. We show that the GR agonist dexamethasone (Dex) downregulates MR levels in a GR-dependent way in myeloma cells. Co-treatment of Dex with the MR antagonist spironolactone (Spi) enhances Dex-induced cell killing in primary, newly diagnosed GC-sensitive myeloma cells. In a relapsed GC-resistant setting, Spi alone induces distinct myeloma cell killing. On a mechanistic level, we find that a GR–MR crosstalk likely arises from an endogenous interaction between GR and MR in myeloma cells. Quantitative dimerization assays show that Spi reduces Dex-induced GR–MR heterodimerization and completely abolishes Dex-induced MR–MR homodimerization, while leaving GR–GR homodimerization intact. Unbiased transcriptomics analyses reveal that c-myc and many of its target genes are downregulated most by combined Dex-Spi treatment. Proteomics analyses further identify that several metabolic hallmarks are modulated most by this combination treatment. Finally, we identified a subset of Dex-Spi downregulated genes and proteins that may predict prognosis in the CoMMpass myeloma patient cohort. Our study demonstrates that GR–MR crosstalk is therapeutically relevant in myeloma as it provides novel strategies for glucocorticoid-based dose-reduction.

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.