Repurposing Riociguat to Target a Novel Paracrine Nitric Oxide-TRPC6 Pathway to Prevent Podocyte Injury.
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ABSTRACT:
SUBMITTER: 't Hart D
PROVIDER: S-EPMC8621407 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Nitric oxide (NO) is a potent signaling molecule involved in many physiological and pathophysiological processes in the kidney. NO plays a complex role in glomerular ultrafiltration, vasodilation, and inflammation. Changes in NO bioavailability in pathophysiological conditions such as hypertension or diabetes may lead to podocyte damage, proteinuria, and rapid development of chronic kidney disease (CKD). Despite the extensive data highlighting essential functions of NO in health and pathology, related signaling in glomerular cells, particularly podocytes, is understudied. Several reports indicate that NO bioavailability in glomerular cells is decreased during the development of renal pathology, while restoring NO level can be beneficial for glomerular function. At the same time, the compromised activity of nitric oxide synthase (NOS) may provoke the formation of peroxynitrite and has been linked to autoimmune diseases such as systemic lupus erythematosus. It is known that the changes in the distribution of NO sources due to shifts in NOS subunits expression or modifications of NADPH oxidases activity may be linked to or promote the development of pathology. However, there is a lack of information about the detailed mechanisms describing the production and release of NO in the glomerular cells. The interaction of NO and other reactive oxygen species in podocytes and how NO-calcium crosstalk regulates glomerular cells' function is still largely unknown. Here, we discuss recent reports describing signaling, synthesis, and known pathophysiological mechanisms mediated by the changes in NO homeostasis in the podocyte. The understanding and further investigation of these essential mechanisms in glomerular cells will facilitate the design of novel strategies to prevent or manage health conditions that cause glomerular and kidney damage.
| S-EPMC9221338 | biostudies-literature
Project description:Tetrandrine (Tet), a compound found in a traditional Chinese medicine, presents the protective effect for kidney function. Our study is aimed at clarifying the efficacy and underlying mechanism of Tet on podocyte injury. In this study, podocyte injury was induced in rats with adriamycin (ADR), and MPC5 podocytes were constructed with TRPC6 overexpression. We found that Tet treatment reduced the levels of proteinuria, serum creatinine, and blood urea nitrogen and increased plasma albumin levels in ADR-induced rats. Tet reduced intracellular Ca2+ influx and apoptosis in MPC5 podocytes overexpressing TRPC6. Tet downregulated the expression of renal TRPC6, RhoA, and ROCK1 and upregulated the expression of synaptopodin; meanwhile, it reduced calcineurin activity in vivo and in vitro. In conclusion, Tet protects against podocyte by affecting TRPC6 and its downstream RhoA/ROCK1 signaling pathway.
| S-EPMC9553700 | biostudies-literature
Project description:BackgroundThe hallmark of podocytopathies, such as FSGS, is podocyte injury resulting in proteinuria. Transient receptor potential channel C6 (TRPC6) is a calcium-conducting ion channel expressed at the slit diaphragm. TRPC6 gain-of-function mutations and glomerular TRPC6 overexpression are associated with proteinuria. However, the pathways linking TRPC6 to podocyte injury, which is characterized by loss of the slit diaphragm protein nephrin, activation of several intracellular pathways (including calcineurin-NFAT signaling), and cytoskeletal rearrangement, remain elusive.MethodsWe tested whether the calcium-dependent protease calpain-1 mediates TRPC6-dependent podocyte injury in human and experimental FSGS and cultured podocytes.ResultsCompared with kidneys of healthy controls, kidneys of patients with FSGS had increased TRPC6 expression, increased calpain and calcineurin activity, and reduced expression of the calpain target Talin-1, which links the actin cytoskeleton to integrins and is critical for podocyte cytoskeletal stability. In a rat model of human FSGS, increased glomerular and urinary calpain activity associated with reduced Talin-1 abundance, enhanced calcineurin activity, and increased proteinuria. Treatment with the calpain inhibitor calpeptin prevented these effects. In cultured podocytes, pharmacologic stimulation of TRPC6-dependent calcium influx increased calpain-1 and calcineurin activity and reduced Talin-1 expression, and knockdown of TRPC6 or calpain-1 prevented these effects.ConclusionsWe elucidated a novel mechanism that links TRPC6 activity to calpain-1 activation and through Talin-1 loss and possibly, calcineurin activation, the podocyte injury characterizing FSGS. Therefore, calpain-1 and/or TRPC6 inhibition could be future therapeutic options to treat patients with FSGS or other podocytopathies.
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Project description:Transient receptor potential channel C6 (TRPC6) gain-of-function mutations and increased TRPC6 expression in podocytes induce glomerular injury and proteinuria. Sildenafil reduces TRPC6 expression and activity in nonrenal cell types, although the mechanism is unknown. Peroxisome proliferator-activated receptor γ (PPAR-γ) is a downstream target of sildenafil in the cyclic guanosine monophosphate (cGMP)-activated protein kinase G (PKG) axis. PPAR-γ agonists, like pioglitazone, appear antiproteinuric. We hypothesized that sildenafil inhibits TRPC6 expression in podocytes through PPAR-γ-dependent mechanisms, thereby counteracting podocyte injury and proteinuria. Treatment with sildenafil, the cGMP derivative 8-bromoguanosine 3',5'-cyclic monophosphate sodium salt (8-Br-cGMP), or pioglitazone dose-dependently downregulated podocyte injury-induced TRPC6 expression in vitro Knockdown or application of antagonists of PKG or PPAR-γ enhanced TRPC6 expression in podocytes and counteracted effects of sildenafil and 8-Br-cGMP. We observed similar effects on TRPC6 promoter activity and TRPC6-dependent calcium influx. Chromatin immunoprecipitation showed PPAR-γ binding to the TRPC6 promoter. Sildenafil or pioglitazone treatment prevented proteinuria and the increased TRPC6 expression in rats with adriamycin-induced nephropathy and mice with hyperglycemia-induced renal injury. Rats receiving PPAR-γ antagonists displayed proteinuria and increased podocyte TRPC6 expression, as did podocyte-specific PPAR-γ knockout mice, which were more sensitive to adriamycin and not protected by sildenafil. Thus, sildenafil ameliorates podocyte injury and prevents proteinuria through cGMP- and PKG-dependent binding of PPAR-γ to the TRPC6 promoter, which inhibits TRPC6 promoter activity, expression, and activity. Because sildenafil is approved for clinical use, our results suggest that additional clinical study of its antiproteinuric effect in glomerular disease is warranted.
| S-EPMC5407711 | biostudies-literature
Project description:Diabetic nephropathy (DN) is the leading cause of end-stage renal failure, and podocyte injury plays a major role in the development of DN. In this study, we investigated whether tacrolimus (FK506), an immunosuppressor, can attenuate podocyte injury in a type 2 diabetic mellitus (T2DM) rat model with DN. Transmission electron microcopy was used to morphologically evaluate renal injury. The urinary albumin (UAL), creatinine clearance rate (Ccr) and major biochemical parameters, including glucose, insulin, serum creatinine (Scr), urea nitrogen, total cholesterol (CHO) and triglyceride (TG), were examined 12 weeks after the administration of FK506. The expressions of the canonical transient receptor potential 6 (TRPC6), nuclear factor of activated T-cells (NFAT) and nephrin were detected by Western blotting and qPCR. In the rat model of DN, the expressions of TRPC6 and NFAT were significantly elevated compared with the normal rat group; however, the treatment with FK506 normalized the increased expression of TRPC6 and NFAT and attenuated podocyte ultrastructure injury. UAL, Ccr and the biochemical parameters were also improved by the use of FK506. In cell experiments, FK506 improved the decreased expression of nephrin and suppressed the elevated expression of both TRPC6 and NFAT caused by high glucose in accordance with TRPC6 blocker U73122. Our results demonstrated that FK506 could ameliorate podocyte injury in T2DM, which may be related to suppressed expressions of TRPC6 and NFAT.
| S-EPMC4713506 | biostudies-literature
Project description:BackgroundNitric oxide-releasing drugs are used for cardiovascular diseases; however, their effects on the tumor immune microenvironment are less clear. Therefore, this study explored the impact of nitric oxide donors on tumor progression in immune-competent mice.MethodsThe effects of three different nitric oxide-releasing compounds (SNAP, SNP, and ISMN) on tumor growth were studied in tumor-bearing mouse models. Three mouse tumor models were used: B16F1 melanoma and LL2 lung carcinoma in C57BL/6 mice, CT26 colon cancer in BALB/c mice, and LL2 lung carcinoma in NOD/SCID mice. After nitric oxide treatment, splenic cytokines and lymphocytes were analyzed by cytokine array and flow cytometry, and tumor-infiltrating lymphocytes in the TME were analyzed using flow cytometry and single-cell RNA sequencing.ResultsLow doses of three exogenous nitric oxide donors inhibited tumor growth in two immunocompetent mouse models but not in NOD/SCID immunodeficient mice. Low-dose nitric oxide donors increase the levels of splenic cytokines IFN-γ and TNF-α but decrease the levels of cytokines IL-6 and IL-10, suggesting an alteration in Th2 cells. Nitric oxide donors increased the number of CD8+ T cells with activation gene signatures, as indicated by single-cell RNA sequencing. Flow cytometry analysis confirmed an increase in infiltrating CD8+ T cells and dendritic cells. The antitumor effect of nitric oxide donors was abolished by depletion of CD8+ T cells, indicating the requirement for CD8+ T cells. Tumor inhibition correlated with a decrease in a subtype of protumor macrophages and an increase in a subset of Arg1-positive macrophages expressing antitumor gene signatures. The increase in this subset of macrophages was confirmed by flow cytometry analysis. Finally, the combination of low-dose nitric oxide donor and cisplatin induced an additive cancer therapeutic effect in two immunocompetent animal models. The enhanced therapeutic effect was accompanied by an increase in the cells expressing the gene signature of NK cell.ConclusionsLow concentrations of exogenous nitric oxide donors inhibit tumor growth in vivo by regulating T cells and macrophages. CD8+ T cells are essential for antitumor effects. In addition, low-dose nitric oxide donors may be combined with chemotherapeutic drugs in cancer therapy in the future.
| S-EPMC9840268 | biostudies-literature
Project description:Gain-of-function mutations of classic transient receptor potential channel 6 (TRPC6) were identified in familial FSGS, and increased expression of wild-type TRPC6 in glomeruli is observed in several human acquired proteinuric diseases. Synaptopodin, an actin binding protein that is important in maintaining podocyte function, is downregulated in various glomerular diseases. Here, we investigated whether synaptopodin maintains podocyte function by regulating podocyte surface expression and activity of TRPC6. We show indirect interaction and nonrandom association of synaptopodin and TRPC6 in podocytes. Knockdown of synaptopodin in cultured mouse podocytes increased the expression of TRPC6 at the plasma membrane, whereas overexpression of synaptopodin decreased it. Mechanistically, synaptopodin-dependent TRPC6 surface expression required functional actin and microtubule cytoskeletons. Overexpression of wild-type or FSGS-inducing mutant TRPC6 in synaptopodin-depleted podocytes enhanced TRPC6-mediated calcium influx and induced apoptosis. In vivo, knockdown of synaptopodin also caused increased podocyte surface expression of TRPC6. Administration of cyclosporin A, which stabilizes synaptopodin, reduced LPS-induced proteinuria significantly in wild-type mice but to a lesser extent in TRPC6 knockout mice. Furthermore, administration of cyclosporin A reversed the LPS-induced increase in podocyte surface expression of TRPC6 in wild-type mice. Our findings suggest that alteration in synaptopodin levels under disease conditions may modify intracellular TRPC6 channel localization and activity, which further contribute to podocyte dysfunction. Reducing TRPC6 surface levels may be a new approach to restoring podocyte function.
| S-EPMC5084886 | biostudies-other
Project description:A growing understanding of endogenous nitric oxide (NO) biology is helping to explain how and when exogenous NO may confer benefit or harm; this knowledge is also helping to identify new better-targeted NO-based therapies. In this review, results of the bronchopulmonary dysplasia clinical trials that used inhaled NO in the preterm population are placed in context, the biologic basis for novel NO therapeutics is considered, and possible future directions for NO-focused clinical and basic research in developmental lung disease are identified.
| S-EPMC3437658 | biostudies-other
Project description:ObjectiveTo analyze the correlation between the expressions of vascular endothelial growth factor (VEGF) and transient receptor potential canonical 6 (TRPC6) and their role in podocyte injury in rats with diabetic nephropathy.MethodsForty SD rats with diabetic nephropathy induced by intraperitoneal injection of 65 mg/kg streptozotocin were randomized equally into 5 groups, including a diabetic nephropathy model group and 4 treatment groups, with 8 normal SD rats as the normal control group. In the 4 treatment groups, the rats received intraperitoneal injections with SU5416 at 5 mg/kg or 10 mg/kg twice a week or with LY294002 at 1 mg/kg or 2 mg/kg once daily for 8 weeks. Blood glucose, serum creatinine, blood urea nitrogen, and 24-h urinary protein levels of the rats were detected at different time points, and the pathologies in the renal tissue were observed using HE staining, PAS staining and immunohistochemistry. The expressions of VEGF, nephrin, and TRPC6 at mRNA and protein levels were detected using RT-PCR and Western blotting.ResultsCompared with normal control rats, the diabetic rats showed significantly increased fasting blood glucose, serum creatinine, blood urea nitrogen and 24-h urinary protein levels with decreased expressions of nephrin mRNA and protein (P<0.05) and increased expressions of VEGF and TRPC6 (P<0.05). Compared with the untreated diabetic rats, the rats with SU5416 treatment showed increased 24-h urinary protein, urea nitrogen, and nephrin expression and decreased TRPC6 expression without significant changes in fasting blood glucose, serum creatinine, or VEGF expression. The rats treated with LY294002 showed decreased 24-h urinary protein and TRPC6 expression without significant changes in fasting blood glucose, serum creatinine, urea nitrogen, or expressions of nephrin and VEGF.ConclusionThe regulatory effect of VEGF on TRPC6 can be blocked by inhibiting VEGFR-2 or blocking PI3K/Akt signaling pathway.
| S-EPMC6744170 | biostudies-literature
Project description:The purpose of this study is to comprehensively elucidate the role of nitric oxide and nitric oxide synthase isoforms in pulmonary emphysema using cap analysis of gene expression (CAGE) sequencing.
2021-01-18 | GSE164521 | GEO