Mechanistic insights into PFAS-induced effects on B lymphocyte activation and antibody secretion.

Central glucocorticoid receptors regulate the upregulation of spinal cannabinoid-1 receptors after peripheral nerve injury in rats

The role of activation of the glucocorticoid receptor (GR) in the response of several solid tumor types to chemotherapy has been reported by several groups. Skor et al1 have demonstrated that the non-selective GR antagonist mifepristone can potentiate the effect of paclitaxel in a mouse xenograft derived from a human triple negative breast cancer (TNBC) cell line. GR activation is thought to play a role in the regulation of pro- and anti-apoptotic genes. Isikbay et al2 have demonstrated the benefits of combining androgen deprivation therapy with GR antagonism in prostate cancer xenograft model. Signaling via GR appears to be able to compensate for lack of androgen receptor signaling, and to contribute to castrate resistance. CORT125134 is a novel, selective GR antagonist being developed for the treatment of a variety of solid tumors, in combination with an appropriate standard of care agent. CORT125134 is currently being studied in a Phase1/2 study in solid tumors, in combination with nab-paclitaxel. The efficacy of CORT125134 in combination with standard of care agents has been investigated in mouse xenograft models of several tumor types. Previous reports of the benefit of adding a GR antagonist to chemotherapy in a TNBC model and an ovarian cancer model have been confirmed. An enhancement of the anti-tumor effect of castration by the addition of a GR antagonist has been confirmed in a model of prostate cancer. In addition, CORT125134 has been shown to provide a significant improvement in the efficacy of paclitaxel in a pancreatic cancer model. In a MIAPaca-2 xenograft model, paclitaxel was given i.v. every 4 days either alone or in combination with CORT125134. The combination provided significantly better tumor group inhibition than paclitaxel alone (p<0.0001). These encouraging results in a pancreatic cancer model extend the potential utility of GR antagonism in a variety of solid tumor types. In the TNBC model, alternative dosing regimens have been investigated, and suggest that stress during dosing is a confounding factor in these studies. 1. Skor MN, Wonder E, Kocherginsky M, et al. Glucocorticoid receptor antagonism as a novel therapy for triple negative breast cancer. Clinical Cancer Res. 2013;19(22):6163-6172. 2. Isikbay M, Otto K, Kregel S, et al. Glucocorticoid receptor activity contributes to resistance to androgen-targeted therapy in prostate cancer. Horm Cancer. 2014;5(2):72-89. Citation Format: Hazel Hunt, Joseph Belanoff, Thad Block, Stacie P. Shepherd. Preclinical efficacy of the selective GR antagonist, CORT125134 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3623. doi:10.1158/1538-7445.AM2017-3623

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

Alcohol use disorder (AUD) is a chronic psychiatric disorder characterized by escalated alcohol use and emergence of negative emotional states during withdrawal. Studies show a dysregulation of glucocorticoid signaling in AUD, affecting the hypothalamic-pituitary-adrenal (HPA) axis and the central amygdala (CeA). Excessive activation of glucocorticoid receptors (GRs) is hypothesized to promote cognitive dysfunction, negative emotional states, and escalated drinking. Previous work demonstrates a functional increase in GR activity in the CeA during alcohol withdrawal in alcohol-dependent animal models. Importantly, the GR antagonist mifepristone reduces alcohol-seeking and drinking behaviors in rodents and humans. The aims of this study were to determine differential CeA protein expression in alcohol-dependent rats and examine the effects of mifepristone treatment. We hypothesized that male and female rats will show sex differences in their CeA protein expression and that alcohol-induced reductions in brain anti-stress signaling (e.g., endocannabinoid system) will be normalized by mifepristone treatment. Male and female Wistar rats were exposed to chronic intermittent ethanol vapor (CIEV) or air (control) for 10 weeks. In week 7, half of each group received subcutaneous placebo pellets while the other half received mifepristone pellets (150mg, 21-day slow release). At the end of Week 10, the rats were sacrificed during acute (6-hour) CIEV withdrawal (and identical time in control groups). The CeA was analyzed using proteomics and ingenuity pathway analysis (IPA). In males, a total of 3050 proteins were detected in the CeA. Of these, 142 proteins were altered by alcohol (but not mifepristone), whereas an additional 253 proteins were altered by alcohol and “normalized” by mifepristone. In females, among the 2632 detected proteins, 46 were affected by alcohol (but not mifepristone), and 25 were altered by alcohol and restored by mifepristone. IPA revealed significant changes in canonical pathways, including the endocannabinoid neuronal synapse pathway and oxidative phosphorylation, affected by alcohol but normalized by mifepristone. Future studies will incorporate alcohol self-administration procedures in male and female rats to functionally examine proteins within these pathways as promising “druggable” targets that offer novel therapeutic avenues for AUD. Supported by NIH-NIAAA R01AA025996, P60AA009803, T32AA007577. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Traumatic brain injury regulates adrenocorticosteroid receptor mRNA levels in rat hippocampus

Differential effects of agonist and antagonists on autoregulation of glucocorticoid receptors in a rat colonic adenocarcinoma cell line.

Cytochromes P450 (CYP) in thePoeciliopsis lucidaHepatocellular Carcinoma Cell Line (PLHC-1): Dose- and Time-Dependent Glucocorticoid Potentiation of CYP1A Induction without Induction of CYP3A

Local facilitation of hippocampal metabotropic glutamate receptor-dependent long-term depression by corticosterone and dexamethasone

BackgroundGlucocorticoid Receptor agonists, particularly classic glucocorticoids, are the mainstay among treatment protocols for various chronic inflammatory disorders, including nasal disease. To steer away from steroid-induced side effects, novel GR modulators exhibiting a more favorable therapeutic profile remain actively sought after. Currently, the impact of 2-(4-acetoxyphenyl)-2-chloro-N-methylethylammonium chloride a plant-derived selective glucocorticoid receptor modulator named compound A, on cytokine production in ex vivo human immune cells and tissue has scarcely been evaluated.Methods and ResultsThe current study aimed to investigate the effect of a classic glucocorticoid versus compound A on cytokine and inflammatory mediator production after stimulation with Staphylococcus aureus–derived enterotoxin B protein in peripheral blood mononuclear cells (PBMCs) as well as in inferior nasal turbinate tissue. To this end, tissue fragments were stimulated with RPMI (negative control) or Staphylococcus aureus–derived enterotoxin B protein for 24 hours, in presence of solvent, or the glucocorticoid methylprednisolone or compound A at various concentrations. Supernatants were measured via multiplex for pro-inflammatory cytokines (IL-1β, TNFα) and T-cell- and subset-related cytokines (IFN-γ, IL-2, IL-5, IL-6, IL-10, and IL-17). In concordance with the previously described stimulatory role of superantigens in the development of nasal polyposis, a 24h Staphylococcus aureus–derived enterotoxin B protein stimulation induced a significant increase of IL-2, IL-1β, TNF-α, and IL-17 in PBMCs and in inferior turbinates and of IL-5 and IFN-γ in PBMCs.ConclusionNotwithstanding some differences in amplitude, the overall cytokine responses to methylprednisolone and compound A were relatively similar, pointing to a conserved and common mechanism in cytokine transrepression and anti-inflammatory actions of these GR modulators. Furthermore, these results provide evidence that selective glucocorticoid receptor modulator-mediated manipulation of the glucocorticoid receptor in human tissues, supports its anti-inflammatory potential.

Lysine 419 targets human glucocorticoid receptor for proteasomal degradation

Alcohol use disorder (AUD) is a psychiatric disorder characterized by escalated alcohol use and the emergence of negative affective symptoms. Studies have described a dysregulation of glucocorticoid receptor (GR) signaling in the context of AUD at the levels of the hypothalamic-pituitary-adrenal (HPA) axis and central amygdala (CeA). A functional increase in CeA GR activity occurs during alcohol withdrawal in alcohol-dependent animal models, and the GR antagonist mifepristone reduces alcohol-seeking and drinking behaviors in both rodents and humans. The aims of this study were to determine differential CeA protein expression in alcohol-dependent rats and examine the effects of mifepristone treatment in this context. Male and female Wistar rats were exposed to chronic intermittent ethanol vapor (CIEV) or air (control) for 10 weeks. In week 7, half of the animals in each group received either subcutaneous placebo pellets or mifepristone pellets. At the end of Week 10, the rats were euthanized during acute CIEV withdrawal (and identical time in control groups). The CeA was analyzed using discovery-based proteomics and Ingenuity Pathway Analysis (IPA). In males, among the 3050 proteins detected, 274 proteins were significantly altered by alcohol, and 158 of these proteins were normalized by mifepristone. In females, among the 2631 detected proteins, 37 proteins were altered by alcohol, and 13 of these proteins were normalized by mifepristone. Alcohol and mifepristone elicited sex-dependent alterations in protein expression within the CeA, confirming and extending previous research to highlight specific proteins and pathways as medication targets to offer novel therapeutic avenues for treating AUD.

While flavonoids have been studied extensively for estrogen receptor activity, they have not been well studied for their ability to modify progesterone receptor (PR) and glucocorticoid receptor (GR) signaling. Three flavonoid compounds, tangeretin, wogonin, and baicalein, were selected for testing for PR and GR activity based on their structural similarity to known phytoprogesterone-like compounds. Each compound was docked in the binding pocket of PR and GR. Of these compounds, baicalein was predicted to be most likely to bind to both receptors. A fluorescence polarization competitive binding assay for PR and GR confirmed that baicalein binds to both the PR and GR with IC50 values of 15.30 μM and 19.26 μM respectively. In Ishikawa PR-B and T47D cells, baicalein acted as a PR antagonist in a hormone response element (HRE) luciferase (Luc) assay. In OVCAR5 cells, which only express GR, baicalein was a GR agonist via an HRE/Luc assay and induced GR target genes, FKBP5 and GILZ. RU486, a PR and GR antagonist, abrogated baicalein’s activity in OVCAR5 cells, confirming baicalein’s activity is mediated through the GR. In vivo, baicalein administered intraperitoneally to female mice twice a week for 4 weeks at a dose of 25 mg/kg induced the GR target gene GILZ in the reproductive tract, which was blocked by RU486. In summary, baicalein has PR antagonist and GR agonist activity in vitro and demonstrates GR agonist activity in the uterus in vivo.

The rational drug design combining the bioassay identified a novel selective androgen receptor (AR) degrader for both AR and AR-VRs and illustrated the synergistic importance of AR antagonism and degradation in advanced prostate cancer treatment.

Exogenous glucocorticoids act within the hindbrain to enhance the arterial pressure response to acute novel stress. Here we tested the hypothesis that endogenous glucocorticoids act at hindbrain glucocorticoid receptors (GR) to augment cardiovascular responses to restraint stress in a model of stress hyperreactivity, the borderline hypertensive rat (BHR). A 3- to 4-mg pellet of the GR antagonist mifepristone (Mif) was implanted over the dorsal hindbrain (DHB) in Wistar-Kyoto (WKY) and BHRs. Control pellets consisted of either sham DHB or subcutaneous Mif pellets. Rats were either subjected to repeated restraint stress (chronic stress) or only handled (acute stress) for 3-4 wk, then all rats were stressed on the final day of the experiment. BHR showed limited adaptation of the arterial pressure response to restraint, and DHB Mif significantly (P </= 0.05) attenuated the arterial pressure response to restraint in both acutely and chronically stressed BHR. In contrast, WKY exhibited a substantial adaptation of the pressure response to repeated restraint that was significantly reversed by DHB Mif. DHB Mif and chronic stress each significantly increased baseline plasma corticosterone concentration and adrenal weight and reduced the corticosterone response to stress in all rats. We conclude that endogenous corticosterone acts via hindbrain GR to enhance the arterial pressure response to stress in BHR, but to promote the adaptation of the arterial pressure response to stress in normotensive rats. Endogenous corticosterone also acts in the hindbrain to restrain corticosterone at rest but to maintain the corticosterone response to stress in both BHR and WKY rats.

Mineralocorticoid and glucocorticoid receptors in the amygdala regulate distinct responses to colorectal distension