ABSTRACT
【Objective】 To explore the role and mechanism of TRPC in promoting extracellular matrix (ECM) deposition in rat glomerular mesangial cells (HBZY-1). Methods Immunofluorescence staining was performed to observe the distribution and expression of TRPC1 and TRPC6 in HBZY-1 cells. After AngⅡ stimulation, qRT-PCR and Western blotting were used to detect the mRNA and protein expressions of Gαq/PLCβ4/TRPC signaling pathway main proteins and ECM deposition indicators (α-SMA, collagenⅢ and fibronectin). By silencing the expressions of TRPC1 and TRPC6 by RNA interference, the expressions of ECM deposition indicators were detected. Changes in [Ca2+]i influx were determined through Fluo-4AM Ca2+ imaging. 【Results】 Both TRPC1 and TRPC6 were expressed in HBZY-1, and were mainly located in cell membrane and cytoplasm. After AngⅡ stimulation, Gαq/PLCβ4/TRPC signaling pathway was activated, and the mRNA and protein expressions of Gαq, PLCβ4, TRPC1 and TRPC6 were all increased (P<0.05). [Ca2+]i influx also increased (P<0.01), and the mRNA and protein expressions of ECM deposition indicators (α-SMA, ColⅢ and Fn) were upregulated (P<0.05). Silencing the expressions of TRPC1 and TRPC6 by RNA interference led to decreased [Ca2+]i influx (P<0.05), and downregulated mRNA and protein expressions of ECM deposition indicators in HBZY-1 cells (P<0.05). The results suggested that inhibition of TRPC expressions could inhibit AngⅡ induced ECM deposition in HBZY-1 cells, which might be associated with decreased [Ca2+]i influx. 【Conclusion】 TRPC may be a novel therapeutic target of renal fibrosis.
ABSTRACT
【Objective】 To explore the role and mechanism of TRPC6 in apoptosis of glomerular mesangial cells (HBZY-1) induced by endoplasmic reticulum stress (ERS). 【Methods】 The experiment groups were classified as follows: normal control (NC), thapsigargin (TG), TG+SKF96365, and TG+TRPC6 siRNA groups. Transcription and protein expressions of TRPC6 and ERS related proteins (GRP78 and Caspase12) were detected by qRT-PCR and Western blotting. Additionally, cell apoptosis was measured by flow cytometry and Hoechst33258. Finally, Fluo-4 AM Ca2+ imaging technique was used to determine changes of intracellular calcium ( [Ca2+] i) by laser scanning confocal microscope. 【Results】 Morphological changes of apoptotic cells were characterized by nuclear enrichment or nuclear fragmentation, and the apoptosis rate was increased after TG stimulation. The expressions of TRPC6 and ERS related proteins (GRP78 and Caspase12) were elevated in TG group compared with NC group (P<0.05). Pre-incubation of HBZY-1 cells with SKF96365 and TRPC6 siRNA decreased cell apoptosis (P<0.05). The entry of [Ca2+] i also increased after TG stimulation (P<0.05). The expressions of TRPC6, GRP78 and Caspase12 were downregulated compared with TG group after treatment with SKF96365 and TRPC6 siRNA accompanied by decreased [Ca2+] i (P<0.05). 【Conclusion】 Taken together, this study suggests that inhibition of TRPC6 can alleviate TG-induced HBZY-1 cell apoptosis.