Transient receptor potential canonical (TRPC) Ca 2+ -permeant channels, especially TRPC3, are increasingly implicated in cardiorenal diseases. We studied the possible role of fibroblast TRPC3 in the development of renal fibrosis. In vitro, a macromolecular complex formed by TRPC1/TRPC3/TRPC6 existed in isolated cultured rat renal fibroblasts. However, specific blockade of TRPC3 with the pharmacologic inhibitor pyr3 was sufficient to inhibit both angiotensin II-and 1-oleoyl-2-acetyl-sn-glycerol-induced Ca 2+ entry in these cells, which was detected by fura-2 Ca 2+ imaging. TRPC3 blockade or Ca 2+ removal inhibited fibroblast proliferation and myofibroblast differentiation by suppressing the phosphorylation of extracellular signalregulated kinase (ERK1/2). In addition, pyr3 inhibited fibrosis and inflammation-associated markers in a noncytotoxic manner. Furthermore, TRPC3 knockdown by siRNA confirmed these pharmacologic findings. In adult male Wistar rats or wild-type mice subjected to unilateral ureteral obstruction, TRPC3 expression increased in the fibroblasts of obstructed kidneys and was associated with increased Ca 2+ entry, ERK1/2 phosphorylation, and fibroblast proliferation. Both TRPC3 blockade in rats and TRPC3 knockout in mice inhibited ERK1/2 phosphorylation and fibroblast activation as well as myofibroblast differentiation and extracellular matrix remodeling in obstructed kidneys, thus ameliorating tubulointerstitial damage and renal fibrosis. In conclusion, TRPC3 channels are present in renal fibroblasts and control fibroblast proliferation, differentiation, and activation through Ca 2+ -mediated ERK signaling. TRPC3 channels might constitute important therapeutic targets for improving renal remodeling in kidney disease.
Salt‐sensitive hypertension is a major risk factor for renal impairment leading to chronic kidney disease. High‐salt diet leads to hypertonic skin interstitial volume retention enhancing the activation of the tonicity‐responsive enhancer‐binding protein (TonEBP) within macrophages leading to vascular endothelial growth factor C (VEGF‐C) secretion and NOS3 modulation. This promotes skin lymphangiogenesis and blood pressure regulation. Whether VEGF‐C administration enhances renal and skin lymphangiogenesis and attenuates renal damage in salt‐sensitive hypertension remains to be elucidated. Hypertension was induced in BALB/c mice by a high‐salt diet. VEGF‐C was administered subcutaneously to high‐salt‐treated mice as well as control animals. Analyses of kidney injury, inflammation, fibrosis, and biochemical markers were performed in vivo. VEGF‐C reduced plasma inflammatory markers in salt‐treated mice. In addition, VEGF‐C exhibited a renal anti‐inflammatory effect with the induction of macrophage M2 phenotype, followed by reductions in interstitial fibrosis. Antioxidant enzymes within the kidney as well as urinary RNA/DNA damage markers were all revelatory of abolished oxidative stress under VEGF‐C. Furthermore, VEGF‐C decreased the urinary albumin/creatinine ratio and blood pressure as well as glomerular and tubular damages. These improvements were associated with enhanced TonEBP, NOS3, and lymphangiogenesis within the kidney and skin. Our data show that VEGF‐C administration plays a major role in preserving renal histology and reducing blood pressure. VEGF‐C might constitute an interesting potential therapeutic target for improving renal remodeling in salt‐sensitive hypertension.
Aims: Cardiac fibroblasts (CFs) are emerging as major contributors to myocardial fibrosis (MF), a final common pathway of many etiologies of heart disease. Here, we studied the functional relevance of transient receptor potential canonical 3 (TRPC3) channels and nuclear factor of activated T cells c3 (NFATc3) signaling in rodent and human ventricular CFs, and whether their modulation would limit MF. Results: A positive feedback loop between TRPC3 and NFATc3 drove a rat ventricular CF fibrotic phenotype. In these cells, polyphenols (extract of grape pomace polyphenol [P.E.]) decreased basal and angiotensin IImediated Ca 2+ entries through a direct modulation of TRPC3 channels and subsequently NFATc3 signaling, abrogating myofibroblast differentiation, fibrosis and inflammation, as well as an oxidative stress-associated phenotype. N(x)-nitro-l-arginine methyl ester (l-NAME) hypertensive rats developed coronary perivascular, sub-epicardial, and interstitial fibrosis with induction of embryonic epicardial progenitor transcription factors in activated CFs. P.E. treatment reduced ventricular CF activation by modulating the TRPC3-NFATc3 pathway, and it ameliorated echocardiographic parameters, cardiac stress markers, and MF in l-NAME hypertensive rats independently of blood pressure regulation. Further, genetic deletion (TRPC3-/-) and pharmacological channel blockade with N-[4-[3,5-Bis(trifluoromethyl)-1H-pyrazol-1-yl]phenyl]-4-methyl-benzenesulfonamide (Pyr10) blunted ventricular CF activation and MF in l-NAME hypertensive mice. Finally, TRPC3 was present in human ventricular CFs and upregulated in MF, whereas pharmacological modulation of TRPC3-NFATc3 decreased proliferation and collagen secretion. Innovation and Conclusion: We demonstrate that TRPC3-NFATc3 signaling is modulated by P.E. and critically regulates ventricular CF phenotype and MF. These findings strongly argue for P.E., through TRPC3 targeting, as potential and interesting therapeutics for MF management. Antioxid. Redox Signal. 30,
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