Novel detoxifier of spironolactone against triptolide-induced hepatotoxicity through inhibition of RPB1 degradation.

ETHNOPHARMACOLOGICAL RELEVANCE: Triptolide is a major bioactive and toxic ingredient isolated from the traditional Chinese herb Tripterygium wilfordii (T. wilfordii) Hook F. It exhibits potent antitumor, immunosuppressive, and anti-inflammatory biological activities; however, its clinical application is hindered by severe systemic toxicity. Two preparations of T. wilfordii, including T. wilfordii glycoside tablets and T. wilfordii tablets, containing triptolide, are commonly used in clinical practice. However, their adverse side effects, particularly hepatotoxicity, limit their safe use. Therefore, it is crucial to discover potent and specific detoxification medicines for triptolide. AIM OF THE STUDY: This study aimed to investigate the detoxification effects and potential mechanism of action of spironolactone on triptolide-induced hepatotoxicity to provide a potential detoxifying strategy for triptolide, thereby promoting the safe applications of T. wilfordii preparations in clinical settings. MATERIALS AND METHODS: Cell viability was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and crystal violet staining. Nuclear fragmentation was visualized using 4',6-diamidino-2-phenylindole (DAPI) staining, and protein expression was analyzed by Western blotting. The inhibitory effect of spironolactone on triptolide-induced hepatotoxicity was evaluated by examining the effects of spironolactone on serum alanine aminotransferase and aspartate aminotransferase levels, as well as liver pathology in a mouse model of triptolide-induced acute hepatotoxicity. Furthermore, a survival assay was performed to investigate the effects of spironolactone on the survival rate of mice exposed to a lethal dose of triptolide. The effect of spironolactone on triptolide-induced global transcriptional repression was assessed through 5-ethynyl uridine staining. RESULTS: Triptolide treatment decreased the cell viability, increased the nuclear fragmentation and the cleaved caspase-3 levels in both hepatoma cells and hepatocytes. It also increased the alanine aminotransferase and aspartate aminotransferase levels, induced the hepatocyte swelling and necrosis, and led to seven deaths out of 11 mice. The above effects could be mitigated by pretreatment with spironolactone. Additionally, molecular mechanism exploration unveiled that spironolactone inhibited triptolide-induced DNA-directed RNA polymerase II subunit RPB1 degradation, consequently increased the fluorescence intensity of 5-ethynyl uridine staining for nascent RNA. CONCLUSIONS: This study shows that spironolactone exhibits a potent detoxification role against triptolide hepatotoxicity, through inhibition of RPB1 degradation induced by triptolide and, in turn, retardation of global transcriptional inhibition in affected cells. These findings suggest a potential detoxification strategy for triptolide that may contribute to the safe use of T. wilfordii preparations.

Inhibitory effects of Eplerenone on angiogenesis via modulating SGK1/TGF-ß pathway in contralateral kidney of CKD pregnancy rats.

BACKGROUND: Eplerenone is a selective aldosterone receptor blocker that is effective in preventing the progression of chroinic kidney disease (CKD). However, its mechanism and role in CKD pregnancy still remain uncertain. The aim of this study was to evaluate whether eplerenone could attenuated the fibrosis of unilateral ureteral obstruction (UUO) pregnant rats' contralateral kidney, improved pregnancy outcome and explore its therapeutic mechanisms. METHODS: A pregnancy rat model of UUO established, female Wistar rats were randomly assigned into sham-operated group (Sham group),sham-operated combined pregnancy group (SP group), unilateral ureteral obstruction combined pregnancy group (UUO + Pregnancy group), unilateral ureteral obstruction combined pregnancy, administered eplerenone (UUO + Pregnancy+Eplerenone group). On the 18th day of pregnancy, the rats were placed in a metabolic cage, 24 h urine was collected and stored at -80 °C. Next day, all animals were euthanized, and serum was collected by centrifugation and stored at -20 °C. Then the right kidney was extracted, a part of the kidney was placed in 4% paraformaldehyde for morphology, immunohistochemical staining, and immunofluorescence staining, and the other part was placed in a - 80 °C refrigerator for RNA and protein extraction. In vitro, HUVECs was treated with aldosterone, progesterone and estradiol, VEGFA and its receptor blocker bevacizumab. The ability of proliferation, migration and tubularization of HUVECs was detected by CCK-8, scratch wound assay and endothelial tube formation assay. And the co-expression of CD34 and α-SMA of HUVECs was detected by Flow cytometry. RESULTS: Immunofluorescence results showed that the co-expression of CD34 and α-SMA increased in the UUO + Pregnancy group was significantly increased. The expression of SGK-1, TGFß-1, Smad2, Smad3, VEGF-A, VEGFR2, CD34, α-SMA and Collagen I was significantly higher in the kidneys of the UUO + Pregnancy group compared to the Sham group and SP group. Eplerenone inhibited the expression of those results. In vitro, the ability of proliferation, migration and tubularization was increased after treated with aldosterone, aldosterone with progesterone and estradiol or VEGFA. Similarly, the expression of α-SMA on the surface of HUVECs treated with aldosterone, aldosterone with progesterone and estradiol were increased, while eplerenone supressed its expression. CONCLUSION: Eplerenone inhibits renal angiogenesis by blocking the SGK-1/TGFß signal transduction pathway, thereby inhibiting the phenotypic transformation of endothelial cells, slowing down renal fibrosis, and reducing kidney damage caused by pregnancy.

The Renin-Angiotensin-Aldosterone System Regulates Sarcoidosis Granulomatous Inflammation.

Rationale: Sarcoidosis is a granulomatous disorder of unclear cause notable for abnormal elevation of blood and tissue ACE1 (angiotensin converting enzyme 1) levels and activity. ACE1 regulates the renin-angiotensin-aldosterone system (RAAS), the terminal product of which is aldosterone, which selectively engages mineralocorticoid receptors to promote inflammation. Objectives: We sought to determine whether the RAAS promotes sarcoidosis granuloma formation and related inflammatory responses. Methods: Using an established ex vivo model, we first determined whether aldosterone was produced by sarcoidosis granulomas and verified the presence of CYP11B2, the enzyme required for its production. We then evaluated the effects of selective inhibitors of ACE1 (captopril), angiotensin type 1 receptor (losartan), and mineralocorticoid receptors (spironolactone, eplerenone) on granuloma formation, reflected by computer image analysis-generated granuloma area, and selected cytokines incriminated in sarcoidosis pathogenesis. Measurements and Main Results: Aldosterone was spontaneously produced by sarcoidosis peripheral blood mononuclear cells, and both intra- and extracellular levels steadily increased during granuloma formation. In parallel, peripheral blood mononuclear cells were shown to express more CYP11B2 during granuloma formation. Significant inhibition of sarcoidosis granulomas and related cytokines (TNFα, IL-1ß, IFNγ, IL-10) was observed in response to pretreatments with captopril, losartan, spironolactone, or eplerenone, comparable to that of prednisone. Conclusions: The RAAS is intact in sarcoidosis granulomas and contributes significantly to early granuloma formation and to related inflammatory mediator responses, with important implications for clinical management.

Therapeutic efficacy of candidate antischistosomal drugs in a murine model of schistosomiasis mansoni.

Schistosomiasis is a neglected tropical disease associated with considerable morbidity. Praziquantel (PZQ) is effective against adult schistosomes, yet, it has little effect on juvenile stages, and PZQ resistance is emerging. Adopting the drug repurposing strategy as well as assuming enhancing the efficacy and lessening the doses and side effects, the present study aimed to investigate the in vivo therapeutic efficacy of the widely used antiarrhythmic, amiodarone, and diuretic, spironolactone, and combinations of them compared to PZQ. Mice were infected by Schistosoma mansoni "S. mansoni" cercariae (Egyptian strain), then they were divided into two major groups: Early- [3 weeks post-infection (wpi)] and late- [6 wpi] treated. Each group was subdivided into seven subgroups: positive control, PZQ, amiodarone, spironolactone, PZQ combined with amiodarone, PZQ combined with spironolactone, and amiodarone combined with spironolactone-treated groups. Among the early-treated groups, spironolactone had the best therapeutic impact indicated by a 69.4% reduction of total worm burden (TWB), 38.6% and 48.4% reduction of liver and intestine egg load, and a significant reduction of liver granuloma number by 49%. Whereas, among the late-treated groups, amiodarone combined with PZQ was superior to PZQ alone evidenced by 96.1% reduction of TWB with the total disappearance of female and copula in the liver and intestine, 53.1% and 84.9% reduction of liver and intestine egg load, and a significant reduction of liver granuloma number by 67.6%. Comparatively, spironolactone was superior to PZQ and amiodarone in the early treatment phase targeting immature stages, while amiodarone had a more potent effect when combined with PZQ in the late treatment phase targeting mature schistosomes.

Combination of spironolactone and DPP-4 inhibitors for treatment of SARS-CoV-2 infection: a literature review.

Coronavirus disease 2019 (COVID-19) is still causing hospitalization and death, and vaccination appears to become less effective with each emerging variant. Spike, non-spike, and other possible unrecognized mutations have reduced the efficacy of recommended therapeutic approaches, including monoclonal antibodies, plasma transfusion, and antivirals. SARS-CoV-2 binds to angiotensin-converting enzyme 2 (ACE2) and probably dipeptidyl peptidase 4 (DPP-4) to initiate the process of endocytosis by employing host proteases such as transmembrane serine protease-2 (TMPRSS-2) and ADAM metallopeptidase domain 17 (ADAM17). Spironolactone reduces the amount of soluble ACE2 and antagonizes TMPRSS-2 and ADAM17. DPP-4 inhibitors play immunomodulatory roles and may block viral entry. The efficacy of treatment with a combination of spironolactone and DPP-4 inhibitors does not appear to be affected by viral mutations. Therefore, the combination of spironolactone and DPP-4 inhibitors might improve the clinical outcome for COVID-19 patients by decreasing the efficiency of SARS-CoV-2 entry into cells and providing better anti-inflammatory, antiproliferative, and antifibrotic effects than those achieved using current therapeutic approaches such as antivirals and monoclonal antibodies.

Gene expression analysis to identify mechanisms underlying improvement of myocardial fibrosis by finerenone in SHR.

Both spironolactone and finerenone treatments significantly reduced SBP and there was no statistical difference in their antihypertensive effects. The differences in body weight (at the end of 1/2/3/4 week) to pre-dose body weight ratio and heart rate (at the end of 1/2/3/4 week) to pre-dose heart rate ratio were not statistically significant in the vehicle, spironolactone, finerenone, and control groups.There was no statistically significant difference in mortality among the vehicle, spironolactone, and finerenone groups. The relative heart mass, ANP, BNP, CVF, Col I, TGF-ß, and Casp-3 were gradually decreased in vehicle group, spironolactone group, and finerenone group. Among them, BNP, CVF, TGF-ß, and Casp-3 were significantly decreased in the finerenone group compared with the vehicle group. HE and Masson staining showed that the cardiomyocytes of rats in the vehicle group and spironolactone group were disorganized, with cell hypertrophy, significantly enlarged cell gaps and a large amount of collagen deposition, whereas the cardiomyocytes of rats in the finerenone group and the control group were more neatly arranged, with smaller cell gaps and a small amount of collagen tissue deposition. RNA sequencing (RNA-seq) showed that there was a total of 119 differentially expressed genes (DEGs) between finerenone treatment and vehicle treatment. Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis showed that the signaling pathways involved were mainly in drug metabolism-cytochrome P450, chemical carcinogenesis, IL-17 signaling pathway, axon guidance, and hematopoietic cell lineage. Protein-protein interaction (PPI) analysis showed that the core genes were Oaslf, Nos2, LOC687780, Rhobtb1, Ephb3, and Rps27a.

Effect of pharmacological heart failure drugs and gene therapy on Danon's cardiomyopathy.

Danon disease is a rare X-linked genetic disease resulting from LAMP2 mutations leading to defective lysosomal function. Heart failure is the main causes of morbidity and mortality. Mice with an LAMP2-exon-6-deletion (L2Δ6), develop cardiac hypertrophy followed by dilated cardiomyopathy, in association with accumulation of autophagosomes, fibrosis and oxidative stress. We investigated the effect of drugs used to treat heart failure and of LAMP2 gene therapy on the phenotype, molecular markers and ROS in LAMP2 cardiomyopathy. L2Δ6 mice were treated with Angiotensin II, Ramipril, Metoprolol or Spironolactone. Gene therapy was delivered by IP injection of Adeno-associated-virus (AAV9) -LAMP2 vector to neonates ("AAVLAMP2-Prevention"), or at 15 weeks of age ("AAVLAMP2-Treatment"). Angiotensin II markedly aggravated the cardiac phenotype. Ramipril and Spironolactone were effective in attenuating left ventricular hypertrophy and preserving the systolic function. Cardiac protection was associated with decreased autophagosome accumulation, reduced fibrosis and oxidative stress. Gene therapy effectively attenuated autophagosome accumulation and ROS in L2Δ6 hearts, lowering troponin release to nearly normal levels. AAVLAMP2-Prevention protected against systolic dysfunction and decreased hypertrophy. AAVLAMP2-Treatment prevented ventricular dilatation and dysfunction but had no effect on wall thickness. We conclude that RAAS inhibitors are highly effective against cardiomyopathy progression in an experimental mouse model of Danon's and shall be considered in human patients for this purpose until novel therapies become clinically available.

Long-term effect of eplerenone treatment in children with chronic allograft nephropathy.

BACKGROUND: Literature supports the protective role of mineralocorticoid antagonist (MRA) against the renal injury induced by aldosterone in kidney transplant recipients. However, there is limited data available regarding the safety and efficacy of MRAs in pediatric renal transplant patients. Therefore, we aimed to investigate the effect of long-term eplerenone administration in children with chronic allograft nephropathy (CAN). METHODS: Twenty-six renal transplant children with biopsy-proven CAN, an estimated glomerular filtration rate (eGFR ) > 40 mL/min per 1.73 m2 and with a significant proteinuria were included. Selected patients were randomly divided into two groups as follows; Group 1 (n = 10) patients received 25 mg/day eplerenone and Group 2 (n = 16) patients did not receive eplerenone for 36 months. Patients were examined in the renal transplant outpatient clinic biweekly for the first month and once a month thereafter. The primary outcome of the patients was compared. RESULTS: Mean eGFR stayed stable in group 1 patients, but significantly decreased in group 2 at 36 months (57.53 ± 7.53 vs. 44.94 ± 8.04 mL/min per 1.73 m2 , p = .001). Similarly, spot protein-creatinine ratio was significantly lower in group 1 compared to group 2 patients at 36 months (1.02 ± 7.53 vs. 3.61 ± 0.53, p < .001). Eplerenone associated hyperkalemia was not observed in group 1 patients (4.6 ± 0.2 vs. 4.56 ± 0.3, p = .713). CONCLUSION: The long-term eplerenone administration blunted the chronic allograft nephropathy by maintaining a stable eGFR levels and decreasing urine protein-creatinine ratio. Eplerenone associated hyperkalemia was not observed in our study.

Randomized Placebo-Controlled Trial to Evaluate Effects of Eplerenone on Myocardial Perfusion and Function Among Persons With Human Immunodeficiency Virus (HIV)-Results From the MIRACLE HIV Study.

BACKGROUND: Increased renin angiotensin aldosterone system (RAAS) activity may contribute to excess cardiovascular disease in people with HIV (PWH). We investigated how RAAS blockade may improve myocardial perfusion, injury, and function among well-treated PWH. METHODS: Forty PWH, on stable ART, without known heart disease were randomized to eplerenone 50 mg PO BID (n = 20) or identical placebo (n = 20) for 12 months. The primary endpoints were (1) myocardial perfusion assessed by coronary flow reserve (CFR) on cardiac PET or stress myocardial blood flow (sMBF) on cardiac MRI or (2) myocardial inflammation by extracellular mass index (ECMi) on cardiac MRI. RESULTS: Beneficial effects on myocardial perfusion were seen for sMBF by cardiac MRI (mean [SD]: 0.09 [0.56] vs -0.53 [0.68] mL/min/g; P = .03) but not CFR by cardiac PET (0.01 [0.64] vs -0.07 [0.48]; P = .72, eplerenone vs placebo). Eplerenone improved parameters of myocardial function on cardiac MRI including left ventricular end diastolic volume (-13 [28] vs 10 [26] mL; P = .03) and global circumferential strain (GCS; median [interquartile range 25th-75th]: -1.3% [-2.9%-1.0%] vs 2.3% [-0.4%-4.1%]; P = .03), eplerenone versus placebo respectively. On cardiac MRI, improvement in sMBF related to improvement in global circumferential strain (ρ = -0.65, P = .057) among those treated with eplerenone. Selecting for those with impaired myocardial perfusion (CFR <2.5 and/or sMBF <1.8), there was a treatment effect of eplerenone versus placebo to improve CFR (0.28 [0.27] vs -0.05 [0.36]; P = .04). Eplerenone prevented a small increase in troponin (0.00 [-0.13-0.00] vs 0.00 [0.00-0.74] ng/L; P = .03) without effects on ECMi (0.9 [-2.3-4.3] vs -0.7 [-2.2--0.1] g/m2; P = .38). CD4+ T-cell count (127 [-38-286] vs -6 [-168-53] cells/µL; P = .02) increased in the eplerenone- versus placebo-treated groups. CONCLUSIONS: RAAS blockade with eplerenone benefitted key indices and prevented worsening of myocardial perfusion, injury, and function among PWH with subclinical cardiac disease when compared with placebo. CLINICAL TRIALS REGISTRATION: NCT02740179 (https://clinicaltrials.gov/ct2/show/NCT02740179?term=NCT02740179&draw=2&rank=1).

Amount of Pannexin 1 in Smooth Muscle Cells Regulates Sympathetic Nerve-Induced Vasoconstriction.

BACKGROUND: Panx1 (pannexin 1) forms high conductance channels that secrete ATP upon stimulation. The role of Panx1 in mediating constriction in response to direct sympathetic nerve stimulation is not known. Additionally, it is unknown how the expression level of Panx1 in smooth muscle cells (SMCs) influences α-adrenergic responses. We hypothesized that the amount of Panx1 in SMCs dictates the levels of sympathetic constriction and blood pressure. METHODS: To test this hypothesis, we used genetically modified mouse models enabling expression of Panx1 in vascular cells to be varied. Electrical field stimulation on isolated arteries and blood pressure were assessed. RESULTS: Genetic deletion of SMC Panx1 prevented constriction by electric field stimulation of sympathetic nerves. Conversely, overexpression of Panx1 in SMCs using a ROSA26 transgenic model increased sympathetic nerve-mediated constriction. Connexin 43 hemichannel inhibitors did not alter constriction. Next, we evaluated the effects of altered SMC Panx1 expression on blood pressure. To do this, we created mice combining a global Panx1 deletion, with ROSA26-Panx1 under the control of an inducible SMC specific Cre (Myh11). This resulted in mice that could express only human Panx1, only in SMCs. After tamoxifen, these mice had increased blood pressure that was acutely decreased by the Panx1 inhibitor spironolactone. Control mice genetically devoid of Panx1 did not respond to spironolactone. CONCLUSIONS: These data suggest Panx1 in SMCs could regulate the extent of sympathetic nerve constriction and blood pressure. The results also show the feasibility humanized Panx1-mouse models to test pharmacological candidates.

Direct actions of dapagliflozin and interactions with LCZ696 and spironolactone on cardiac fibroblasts of patients with heart failure and reduced ejection fraction.

AIMS: Inhibitors of SGLT2 (SGLT2i) have shown a positive impact in patients with chronic heart failure and reduced ejection fraction (HFrEF). Nonetheless, the direct effects of SGLT2i on cardiac cells and how their association with main drugs used for HFrEF affect the behaviour and signalling pathways of myocardial fibroblasts are still unknown. We aimed to determine the effects of dapagliflozin alone and in combination with sacubitril/valsartan (LCZ696) or spironolactone on the function of myocardial fibroblasts of patients with heart failure and reduced ejection fraction (HFrEF). METHODS AND RESULTS: Myocardial fibroblasts isolated from HFrEF patients (n = 5) were treated with dapagliflozin alone (1 nM-1 µM) or combined with LCZ696 (100 nM) or spironolactone (100 nM). The migratory rate was determined by wound-healing scratch assay. Expression of heart failure (HF) markers and signalling pathways activation were analysed with multiplexed protein array. Commercially available cardiac fibroblasts from healthy donors were used as Control (n = 4). Fibroblasts from HFrEF show higher migratory rate compared with control (P = 0.0036), and increased expression of HF markers [fold-change (Log2): COL1A1-1.3; IL-1b-1.9; IL-6-1.7; FN1-2.9 (P < 0.05)]. Dapagliflozin slowed the migration rate of HFrEF fibroblasts in a dose-dependent manner and markedly decreased the expression of IL-1ß, IL-6, MMP3, MMP9, GAL3, and FN1. SGLT2i had no effect on control fibroblasts. These effects were associated with decreased phosphorylation of AKT/GSK3 and PYK2 kinases and the signal transducer and activator of transcription (STAT). A combination of dapagliflozin + LCZ696 further decreased fibroblast migration, although it did not have a significant effect on the regulation of signalling pathways and the expression of biomarkers induced by SGLT2 inhibition alone. In contrast, the combination of dapagliflozin + spironolactone did not change the migration rate of fibroblast but significantly altered SGLT2i responses on MMP9, GAL3, and IL-1b expression, in association with increased phosphorylation of the kinases AKT/GSK3 and ERK1/2. CONCLUSIONS: SGLT2i, LCZ696, and spironolactone modulate the function of isolated myocardial fibroblasts from HFrEF patients through the activation of different signalling pathways. The combination of SGLT2i + LCZ696 shows an additive effect on migration, while spironolactone modifies the signalling pathways activated by SGLT2i and its beneficial effects of biomarkers of heart failure.

Spontaneous Remission of Primary Aldosteronism with Mineralocorticoid Receptor Antagonist Therapy: A Review.

In this review, we describe previous basic and clinical studies on autonomous aldosterone production. Over the past decades, mineralocorticoid receptor antagonists (MRAs) have been found to concentration-dependently inhibit steroidogenesis in different degrees. However, many studies have proven the suppressive effects of MRAs on the activities of hormone synthase. The probable factors of cytochrome P-450 reduction, both in microsomes and mitochondria, have also been considered: (1) one of the spironolactone metabolite forms had destructive function, except canrenone, (2) 7α-thio-spironolactone was an obligatory intermediate in the spironolactone-induced CYP450 decrease, and (3) the contributing steroids should have 7α-methylthio or 7α-methylsulfone groups. In previous clinical research, spironolactone-body-containing cells showed a type II pattern of enzyme activity (i.e., enhanced 3ß-hydroxysteroid dehydrogenase, glucose-6-phosphate, and NADP-isocitrate dehydrogenase activities and weaken succinate dehydrogenase activity), and the subcapsular micronodules composed of spironolactone-body-containing cells also exhibited a type II pattern and excess aldosterone secretion, indicating that the subcapsular micronodules might be the root of aldosterone-producing adenoma. Moreover, combined with the potential impeditive function to aldosterone secretion, a few cases of spontaneous remission of primary aldosteronism, with normal ranges of blood pressure, plasma potassium, plasma renin activity, and aldosterone renin ratio, have been reported after long-term treatment with MRAs.

Spirolactone-type and enmein-type derivatives as potential anti-cancer agents derived from oridonin.

Natural products (NPs) are always the important sources in the field of drug discovery, among which spirolactone-type and enmein-type compounds exhibit a wide range of biological activities, especially anti-tumor activity. Based on previous studies, the spirolactone-type and enmein-type compounds could be derived from natural oridonin (1) by several chemical reactions. Herein, a series of novel spirolactone-type and enmein-type derivatives with different aryl allyl ester substitutions at their C-14 hydroxyl group were designed and synthesized. The anti-tumor activity results showed that most of the compounds exhibited better anti-proliferative activities than parent compound oridonin, and the most potent compound had an IC50 value of 0.40 µM in K562 cells. Further mechanistic studies revealed that the optimal compound could arrest K562 cells at G2/M phase by inhibiting cdc-2, cdc-25c and cyclin B1 expression. In addition, the optimal compound induced apoptosis in K562 cells through increasing ROS production and depolarizing mitochondrial membrane potential. Collectively, these valuable results suggested that the most potent compound could be an anti-tumor agent candidate and is worthy of further investigation.

Mineralocorticoid receptor-antagonism prevents COVID-19-dependent glycocalyx damage.

Proinflammatory cytokines target vascular endothelial cells during COVID-19 infections. In particular, the endothelial glycocalyx (eGC), a proteoglycan-rich layer on top of endothelial cells, was identified as a vulnerable, vasoprotective structure during infections. Thus, eGC damage can be seen as a hallmark in the development of endothelial dysfunction and inflammatory processes. Using sera derived from patients suffering from COVID-19, we could demonstrate that the eGC became progressively worse in relation to disease severity (mild vs severe course) and in correlation to IL-6 levels. This could be prevented by administering low doses of spironolactone, a well-known and highly specific aldosterone receptor antagonist. Our results confirm that SARS-CoV-2 infections cause eGC damage and endothelial dysfunction and we outline the underlying mechanisms and suggest potential therapeutic options.

Esaxerenone Blocks Vascular Endothelial Inflammation Through SGK1.

ABSTRACT: Chronic low-grade inflammation and excess mineralocorticoid receptor (MR) activation are well-known pathological conditions of metabolic syndrome (MetS). To elucidate the crosstalk between inflammation and MR signaling, we focused on serum/glucocorticoid-regulated kinase 1 (SGK1) in vascular endothelial cells. We treated human aortic endothelial cells (HAECs) with esaxerenone (ESX), a novel nonsteroidal highly selective MR antagonist, or spironolactone (SPL), a classic competitive MR antagonist, followed by stimulation with tumor necrosis factor (TNF)-α. ESX at therapeutic concentrations attenuated the long-term induction of TNF-α-stimulated inflammatory molecules in HAEC, whereas SPL had only a minor effect at 10 µM. We found long-term TNF-α-stimulated induction of SGK1 mRNA and protein levels in HAEC and that ESX pretreatment significantly decreased SGK1 mRNA and protein levels at both the basal and the TNF-α-stimulated conditions, whereas SPL had no effect on SGK1 mRNA and protein levels. In addition, the TNF-α-induced nuclear factor kappa-light-chain-enhancer of activated B cell activity was suppressed by the treatment with ESX, and it was abrogated by SGK1 overexpression. These results indicated that ESX has direct anti-inflammatory effects in HAEC via the blocking of long-term TNF-α-induced SGK1 activation and that SGK1 could be a key molecule linking cytokine-induced vascular chronic inflammation and MR activation.

A quantitative systems pharmacology model of plasma potassium regulation by the kidney and aldosterone.

Plasma potassium regulation within a narrow range is vital for life. The risk for hyperkalemia increases when kidney function is impaired and with therapeutic interventions such as mineralocorticoid receptor antagonists (MRAs). The kidney maintains potassium homeostasis by matching potassium intake and excretion, in part through the action of aldosterone. A mechanistic mathematical model was developed and used to investigate the effect of renal impairment and MRAs on plasma potassium levels. The model describes renal potassium filtration, reabsorption, and secretion along the nephron; potassium-aldosterone regulatory feedbacks; whole body potassium balance; and the pharmacologic effects of MRAs. The model was calibrated by fitting (1) the plasma potassium and aldosterone response to potassium infusion in humans on high/low potassium diets, and (2) the acute potassium excretion response to spironolactone. The model was validated by predicting steady-state plasma potassium with sustained spironolactone treatment in hyperaldosteronism patients. The model was then used to demonstrate that (1) declining renal function alone has a small effect on plasma potassium for GFR > 30 ml/min, but an increasing effect as GFR approaches end stage renal disease (GFR ~ 15 ml/min) (2) the effect of increasing potassium intake has minimal effect at normal GFRs but increasing effect on plasma potassium as GFR declines, and 3) MRAs have a minor effect on plasma potassium when GFR is normal, but cause larger increases as GFR falls below 60 ml/min. This model provides a quantitative framework for investigating integrated impacts of diseases and therapies in this complex system.

Spironolactone Ameliorates Cochlear Implant Induced Endolymphatic Hydrops.

BACKGROUND: Endolymphatic hydrops (EH) has been observed in both animal and human cochleae following cochlear implant (CI) surgery. We tested whether EH could be eliminated by administration of mineralocorticoid steroid antagonist spironolactone and explored the electrophysiological consequences of this. METHODS: Sixty-four adult guinea pigs underwent cochlear implantation with a dummy electrode. Animals then survived either 2, 7, or 28 days. Auditory function was monitored by recording electrocochleography from the round window membrane preimplantation, and on the last day of the experiment. Spironolactone or control solution was added to animals' feed for 7 days (if they survived that long) beginning immediately prior to surgery. The presence of EH was determined using thin-sheet laser imaging microscopy. RESULTS: Treatment with spironolactone resulted in significant reduction in EH in the second cochlear turn 7 days postimplantation. In all animals, the compound action potential (CAP) threshold was elevated 2 days postimplantation, but for most frequencies had recovered substantially by 28 days. There was no treatment effect on CAP thresholds. SP/AP ratios were elevated at day 2. The amplitude growth of the CAP did not differ between test and control groups at any time after implantation. CONCLUSIONS: EH can be suppressed by antagonism of mineralocorticoid receptors in the week after cochlear implantation. Reduction in EH did not lead to any change in hearing, and there was no indication of synaptopathy signalled by reduced CAP amplitude at high sound intensities. We found no electrophysiological evidence that EH early after implantation impacts negatively upon preservation of residual hearing.

Low-dose spironolactone abates cardio-renal disorder by reduction of BAX/inflammasome expression in experimentally induced polycystic ovarian syndrome rat model.

The impact of low-dose spironolactone (LSPL) on polycystic ovarian syndrome (PCOS)-associated cardio-renal disorder is unknown. Therefore, the present study hypothesized that LSPL would ameliorate cardio-renal disorders in experimental PCOS animals. Eight-week-old female Wistar rats were allotted into three groups. The control group received vehicle (distilled water; per os (p.o.)), the letrozole (LET)-treated group designated as PCOS group received LET (1 mg/kg; p.o.), and PCOS+LSPL received LET and LSPL (0.25 mg/kg, p.o.). The treatment was done once daily for 21 days uninterrupted. The experimental PCOS rats were characterized with insulin resistance, as well as elevated testosterone and luteinizing hormone/follicle-stimulating hormone, with a significant increase in cardiac and renal lipid profile, oxidative stress, inflammatory biomarkers (nuclear factor-κB and tumor necrosis factor-α), lactate dehydrogenase and lactate content and decrease in cardiac and renal antioxidant system (glutathione peroxidase and reduced glutathione) compared with the control rats. In addition, immunohistochemical assessment of cardiac and renal tissue showed significant expression of inflammasome and B-cell lymphoma-2 associated X-protein (BAX) in animals with PCOS. Nevertheless, these perturbations were attenuated following the administration of LSPL. Collectively, the present results suggest that LSPL attenuates PCOS-associated cardio-renal disorders by reduction of oxidative stress and BAX/inflammasome expression.

A Preclinical Study to Repurpose Spironolactone for Enhancing Chemotherapy Response in Bladder Cancer.

Neoadjuvant chemotherapy (NAC) followed by radical cystectomy is the standard-of-care for patients with muscle-invasive bladder cancer (MIBC). Defects in nucleotide excision repair (NER) are associated with improved responses to NAC. Excision Repair Cross-Complementation group 3 (ERCC3) is a key component of NER process. No NER inhibitors are available for treating patients with bladder cancer. We have developed an ex vivo cell-based assay of 6-4 pyrimidine-pyrimidinone (6-4PP) removal as a surrogate measure of NER capacity in human bladder cancer cell lines. The protein expression of ERCC3 was examined in human MIBC specimens and cell lines. Small molecule inhibitors were screened for NER inhibition in bladder cancer cell lines. Spironolactone was identified as a potent NER inhibitor. Combined effects of spironolactone with chemo-drugs were evaluated in vitro and in vivo. The efficacy between platinum and spironolactone on cytotoxicity was determined by combination index. A correlation between NER capacity and cisplatin sensitivity was demonstrated in a series of bladder cancer cell lines. Further, siRNA-mediated knockdown of ERCC3 abrogated NER capacity and enhanced cisplatin cytotoxicity. Spironolactone inhibited ERCC3 protein expression, abrogated NER capacity, and increased platinum-induced cytotoxicity in bladder cancer cells in vivo and in patient-derived organoids. Moreover, spironolactone exhibited the potential synergism effects with other clinical chemotherapy regimens in bladder cancer cell lines. Our data support the notion of repurposing spironolactone for improving the chemotherapy response of NAC in patients with MIBC. Further clinical trials are warranted to determine the safety and efficacy of spironolactone in combination with chemotherapy.

Aldosterone and dexamethasone activate African lungfish mineralocorticoid receptor: Increased activation after removal of the amino-terminal domain.

Aldosterone, the main physiological mineralocorticoid in humans and other terrestrial vertebrates, first appears in lungfish, which are lobe-finned fish that are forerunners of terrestrial vertebrates. Aldosterone activation of the MR regulates internal homeostasis of water, sodium and potassium, which was critical in the conquest of land by vertebrates. We studied transcriptional activation of the slender African lungfish MR by aldosterone, other corticosteroids and progesterone and find that aldosterone, 11-deoxycorticosterone, 11-deoxycortisol and progesterone have half-maximal responses (EC50 s) below 1 nM and are potential physiological mineralocorticoids. In contrast, EC50 s for corticosterone and cortisol were 23 nM and 66 nM, respectively. Unexpectedly, truncated lungfish MR, consisting of the DNA-binding, hinge and steroid-binding domains, had a stronger response to corticosteroids and progesterone than full-length lungfish MR, indicating that the N-terminal domain represses steroid activation of lungfish MR, unlike human MR in which the N-terminal domain contains an activation function. BLAST searches of GenBank did not retrieve a GR ortholog, leading us to test dexamethasone and triamcinolone for activation of lungfish MR. At 10 nM, both synthetic glucocorticoids are about 4-fold stronger than 10 nM aldosterone in activating full-length lungfish MR, leading us to propose that lungfish MR also functions as a GR.