Inhibitors of the renin-angiotensin system ameliorates clinical and pathological aspects of experimentally induced nephrotoxic serum nephritis

Renoprotective Effect of TP0472993, a Novel and Selective 20-Hydroxyeicosatetraenoic Acid Synthesis Inhibitor, in Mouse Models of Renal Fibrosis

Kidney fibrosis is considered the essential pathophysiological process for the progression of chronic kidney disease (CKD) toward renal failure. 20-Hydroxyeicosatetraenoic acid (20-HETE) has crucial roles in modulating the vascular response in the kidney and the progression of albuminuria. However, the roles of 20-HETE in kidney fibrosis are largely unexplored. In the current research, we hypothesized that if 20-HETE has important roles in the progression of kidney fibrosis, 20-HETE synthesis inhibitors might be effective against kidney fibrosis. To verify our hypothesis, this study investigated the effect of a novel and selective 20-HETE synthesis inhibitor, TP0472993, on the development of kidney fibrosis after folic acid- and obstructive-induced nephropathy in mice. Chronic treatment with TP0472993 at doses of 0.3 and 3 mg/kg twice a day attenuated the degree of kidney fibrosis in the folic acid nephropathy and the unilateral ureteral obstruction (UUO) mice, as demonstrated by reductions in Masson's trichrome staining and the renal collagen content. In addition, TP0472993 reduced renal inflammation, as demonstrated by markedly reducing interleukin-1β (IL-1β) and tumor necrosis factor alpha (TNF-α) levels in the renal tissue. Chronic treatment with TP0472993 also reduced the activity of extracellular signal-regulated kinase 1/2 (ERK1/2) and signal transducer and activator of transcription 3 (STAT3) in the kidney of UUO mice. Our observations indicate that inhibition of 20-HETE production with TP0472993 suppresses the kidney fibrosis progression via a reduction in the ERK1/2 and STAT3 signaling pathway, suggesting that 20-HETE synthesis inhibitors might be a novel treatment option against CKD. SIGNIFICANCE STATEMENT: In this study, we demonstrate that the pharmacological blockade of 20-hydroxyeicosatetraenoic acid (20-HETE) synthesis using TP0472993 suppresses the progression of kidney fibrosis after folic acid- and obstructive-induced nephropathy in mice, indicating that 20-HETE might have key roles in the pathogenesis of kidney fibrosis. TP0472993 has the potential to be a novel therapeutic approach against chronic kidney disease.

Comprehensive analyses of the microRNA-messenger RNA-transcription factor regulatory network in mouse and human renal fibrosis

Objective: The aim of this study was to construct a microRNA (miRNA)-messenger RNA (mRNA)-transcription factor (TF) regulatory network and explore underlying molecular mechanisms, effective biomarkers, and drugs in renal fibrosis (RF). Methods: A total of six datasets were downloaded from Gene Expression Omnibus. "Limma" and "DESeq2" packages in R software and GEO2R were applied to identify the differentially expressed miRNAs and mRNAs (DEmiRNAs and DEmRNAs, respectively). The determination and verification of DEmiRNAs and DEmRNAs were performed through the integrated analysis of datasets from five mouse 7 days of unilateral ureteral obstruction datasets and one human chronic kidney disease dataset and the Human Protein Atlas (http://www.proteinatlas.org). Target mRNAs of DEmiRNAs and TFs were predicted by prediction databases and the iRegulon plugin in Cytoscape, respectively. A protein-protein interaction network was constructed using STRING, Cytoscape v3.9.1, and CytoNCA. Functional enrichment analysis was performed by DIANA-miRPath v3.0 and R package "clusterProfiler." A miRNA-mRNA-TF network was established using Cytoscape. Receiver operating characteristic (ROC) curve analysis was used to examine the diagnostic value of the key hub genes. Finally, the Comparative Toxicogenomics Database and Drug-Gene Interaction database were applied to identify potential drugs. Results: Here, 4 DEmiRNAs and 11 hub genes were determined and confirmed in five mouse datasets, of which Bckdha and Vegfa were further verified in one human dataset and HPA, respectively. Moreover, Bckdha and Vegfa were also predicted by miR-125a-3p and miR-199a-5p, respectively, in humans as in mice. The sequences of miR-125a-3p and miR-199a-5p in mice were identical to those in humans. A total of 6 TFs were predicted to regulate Bckdha and Vegfa across mice and humans; then, a miRNA-mRNA-TF regulatory network was built. Subsequently, ROC curve analysis showed that the area under the curve value of Vegfa was 0.825 (p = 0.002). Finally, enalapril was identified to target Vegfa for RF therapy. Conclusion: Pax2, Pax5, Sp1, Sp2, Sp3, and Sp4 together with Bckdha-dependent miR-125a-3p/Vegfa-dependent miR-199a-5p formed a co-regulatory network enabling Bckdha/Vegfa to be tightly controlled in the underlying pathogenesis of RF across mice and humans. Vegfa could act as a potential novel diagnostic marker and might be targeted by enalapril for RF therapy.

Renin-Angiotensin System Pathway Therapeutics Associated With Improved Outcomes in Males Hospitalized With COVID-19

OBJECTIVES

To determine whether angiotensin receptor blockers (ARBs) or angiotensin-converting enzyme (ACE) inhibitors are associated with improved outcomes in hospitalized patients with COVID-19 according to sex and to report sex-related differences in renin-angiotensin system (RAS) components.

DESIGN

Prospective observational cohort study comparing the effects of ARB or ACE inhibitors versus no ARBs or ACE inhibitors in males versus females. Severe acute respiratory syndrome coronavirus 2 downregulates ACE-2, potentially increasing angiotensin II (a pro-inflammatory vasoconstrictor). Sex-based differences in RAS dysregulation may explain sex-based differences in responses to ARBs because the ACE2 gene is on the X chromosome. We recorded baseline characteristics, comorbidities, prehospital ARBs or ACE inhibitor treatment, use of organ support and mortality, and measured RAS components at admission and days 2, 4, 7, and 14 in a subgroup ( n = 46), recorded d -dimer ( n = 967), comparing males with females.

SETTING

ARBs CORONA I is a multicenter Canadian observational cohort of patients hospitalized with acute COVID-19. This analysis includes patients admitted to 10 large urban hospitals across the four most populated provinces.

PATIENTS

One-thousand six-hundred eighty-six patients with polymerase chain reaction-confirmed COVID-19 (February 2020 to March 2021) for acute COVID-19 illness were included.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Males on ARBs before admission had decreased use of ventilation (adjusted odds ratio [aOR] = 0.52; p = 0.007) and vasopressors (aOR = 0.55; p = 0.011) compared with males not on ARBs or ACE inhibitors. No significant effects were observed in females for these outcomes. The test for interaction was significant for use of ventilation ( p = 0.006) and vasopressors ( p = 0.044) indicating significantly different responses to ARBs according to sex. Males had significantly higher plasma ACE-1 at baseline and angiotensin II at day 7 and 14 than females.

CONCLUSIONS

ARBs use was associated with less ventilation and vasopressors in males but not females. Sex-based differences in RAS dysregulation may contribute to sex-based differences in outcomes and responses to ARBs in COVID-19.

Activation of the renal GLP-1R leads to expression of Ren1 in the renal vascular tree

The GLP‐1 receptor (GLP‐1R) in the kidney is expressed exclusively in vascular smooth muscle cells in arteries and arterioles. Downstream effects of the activation of the renal vascular GLP‐1R are elusive but may involve regulation of the renin‐angiotensin‐aldosterone system (RAAS). The expression of Ren1 in the mouse renal vasculature was investigated by in situ hybridization after a single subcutaneous dose of liraglutide, semaglutide and after repeated injections of liraglutide. Single and repeated exposure to GLP‐1R agonists induced expression of Ren1 in the renal vascular smooth muscle cell compartment compared with vehicle injected controls (p < .0001) for both semaglutide and liraglutide. The present data show a robust induction of Ren1 expression in the vascular smooth muscle cells of the kidney after single and repeated GLP‐1R activation and this renin recruitment may be involved in the effects of GLP‐1R agonist treatment on kidney disease.

Liraglutide Improves the Kidney Function in a Murine Model of Chronic Kidney Disease

BACKGROUND

Chronic kidney disease (CKD) is a global health burden, and the current treatment options only slow down the disease progression. GLP-1 receptor agonists (GLP-1 RA) have shown a renal protective effect in models of CKD; however, the mechanism behind the beneficial effect is not understood. In this study, we investigate the effect of the GLP-1 RA liraglutide in the nephrotoxic serum nephritis (NTN) CKD model. Moreover, we compare the gene expression pattern of liraglutide-treated mice to the gene expression pattern of mice treated with the angiotensin converting enzyme inhibitor, enalapril.

METHODS

The effect of liraglutide was tested in the NTN model by evaluating the glomerular filtration rate (GFR), albuminuria, mesangial expansion, renal fibrosis, and renal inflammation. Furthermore, the regulation of selected genes involved in CKD and in glomerular, cortical tubulointerstitial, and whole kidney structures was analyzed using a gene expression array on samples following laser capture microdissection.

RESULTS

Treatment with liraglutide improved CKD hallmarks including GFR, albuminuria, mesangial expansion, renal inflammation, and renal fibrosis. The gene expression revealed that both liraglutide and enalapril reversed the regulation of several fibrosis and inflammation associated genes, which are also regulated in human CKD patients. Furthermore, liraglutide and enalapril both regulated genes in the kidney involved in blood pressure control.

CONCLUSIONS

Treatment with liraglutide improved the kidney function and diminished renal lesions in NTN-induced mice. Both liraglutide and enalapril reversed the regulation of genes involved in CKD and regulated genes involved in blood pressure control.