scholarly journals Interaction between V-ATPase B2 and (Pro) renin Receptors in Promoting the progression of Renal Tubulointerstitial Fibrosis

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Yun Liu ◽  
Sujun Zuo ◽  
Xiaoyan Li ◽  
Jinjin Fan ◽  
Xueqin Cao ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Smooth Muscle Actin ◽  
Tubulointerstitial Fibrosis ◽  
Dependent Manner ◽  
Tubular Epithelial Cells ◽  
Atpase Inhibitor ◽  
Renal Tubulointerstitial Fibrosis ◽  
Proximal Tubular Epithelial Cells ◽  
Proximal Tubular ◽  
Atpase Subunits

Abstract To investigate the levels of (Pro) renin receptor [(P) RR], α-smooth muscle actin (α-SMA), fibronectin (FN), and vacuolar H+-ATPase (V-ATPase) subunits (B2, E, and c) in rat unilateral ureteral obstruction (UUO) models and rat proximal tubular epithelial cells (NRK-52E) treated with prorenin to elucidate the role of V-ATPase in these processes by activating the (P) RR. UUO significantly upregulated (P) RR, V-ATPase subunits, α-SMA and FN expression in tubulointerstitium or tubular epithelial cells. A marked colocalization of (P) RR and the B2 subunit was also observed. Prorenin treatment upregulated α-SMA, FN, (P) RR, and V-ATPase subunits and activity in NRK52E cell in a dose- and time-dependent manner. The V-ATPase inhibitor bafilomycin A1 partially blocked prorenin-induced (P) RR, FN, and α-SMA expression. Co-immunoprecipitate and immunofluorescence results demonstrated that the V-ATPase B2 subunit bound to the (P) RR, which was upregulated after prorenin stimulation. Either siRNA-mediated (P) RR or B2 subunit knockdown partially reduced V-ATPase activity and attenuated prorenin-induced FN and α-SMA expression. From the data we can assume that activation of (P) RR and V-ATPase may play an important role in tubulointerstitial fibrosis with possible involvement of interaction of V-ATPase B2 subunit and (P)RR.

V-ATPase promotes transforming growth factor-β-induced epithelial-mesenchymal transition of rat proximal tubular epithelial cells

2012 ◽  
Vol 302 (9) ◽  
pp. F1121-F1132 ◽  
Author(s):  
Xueqin Cao ◽  
Qiongqiong Yang ◽  
Jing Qin ◽  
Shili Zhao ◽  
Xiaoyan Li ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epithelial Cells ◽  
Transforming Growth Factor ◽  
Tubulointerstitial Fibrosis ◽  
Dependent Manner ◽  
Tubular Epithelial Cells ◽  
Mesenchymal Transition ◽  
Proximal Tubular Epithelial Cells ◽  
Proximal Tubular ◽  
Tgf Β1

The ubiquitous vacuolar H+-ATPase (V-ATPase), a multisubunit proton pump, is essential for intraorganellar acidification. Here, we hypothesized that V-ATPase is involved in the pathogenesis of kidney tubulointerstitial fibrosis. We first examined its expression in the rat unilateral ureteral obstruction (UUO) model of kidney fibrosis and transforming growth factor (TGF)-β1-mediated epithelial-to-mesenchymal transition (EMT) in rat proximal tubular epithelial cells (NRK52E). Immunofluorescence experiments showed that UUO resulted in significant upregulation of V-ATPase subunits (B2, E, and c) and α-smooth muscle actin (α-SMA) in areas of tubulointerstitial injury. We further observed that TGF-β1 (10 ng/ml) treatment resulted in EMT of NRK52E (upregulation of α-SMA and downregulation of E-cadherin) in a time-dependent manner and significant upregulation of V-ATPase B2 and c subunits after 48 h and the E subunit after 24 h, by real-time PCR and immunoblot analyses. The ATP hydrolysis activity tested by an ATP/NADH-coupled assay was increased after 48-h TGF-β1 treatment. Using intracellular pH measurements with the SNARF-4F indicator, Na+-independent pH recovery was significantly faster after an NH4Cl pulse in 48-h TGF-β1-treated cells than controls. Furthermore, the V-ATPase inhibitor bafilomycin A1 partially protected the cells from EMT. TGF-β1 induced an increase in the cell surface expression of the B2 subunit, and small interfering RNA-mediated B2 subunit knockdown partially reduced the V-ATPase activity and attenuated EMT induced by TGF-β1. Together, these findings show that V-ATPase may promote EMT and chronic tubulointerstitial fibrosis due to increasing its activity by either overexpression or redistribution of its subunits.

scholarly journals Inhibition of ROCK2 alleviates renal fibrosis and the metabolic disorders in the proximal tubular epithelial cells

2020 ◽  
Vol 134 (12) ◽  
pp. 1357-1376 ◽  
Author(s):  
Ran You ◽  
Wei Zhou ◽  
Yanwei Li ◽  
Yue Zhang ◽  
Songming Huang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Renal Fibrosis ◽  
Tubulointerstitial Fibrosis ◽  
Related Factor ◽  
Tubular Epithelial Cells ◽  
Renal Tubulointerstitial Fibrosis ◽  
Proximal Tubular Epithelial Cells ◽  
Proximal Tubular ◽  
Tgf Β1

Abstract Non-specific inhibition of Rho-associated kinases (ROCKs) alleviated renal fibrosis in the unilateral ureteral obstruction (UUO) model, while genetic deletion of ROCK1 did not affect renal pathology in mice. Thus, whether ROCK2 plays a role in renal tubulointerstitial fibrosis needs to be clarified. In the present study, a selective inhibitor against ROCK2 or genetic approach was used to investigate the role of ROCK2 in renal tubulointerstitial fibrosis. In the fibrotic kidneys of chronic kidney diseases (CKDs) patients, we observed an enhanced expression of ROCK2 with a positive correlation with interstitial fibrosis. In mice, the ROCK2 protein level was time-dependently increased in the UUO model. By treating CKD animals with KD025 at the dosage of 50 mg/kg/day via intraperitoneal injection, the renal fibrosis shown by Masson’s trichrome staining was significantly alleviated along with the reduced expression of fibrotic genes. In vitro, inhibiting ROCK2 by KD025 or ROCK2 knockdown/knockout significantly blunted the pro-fibrotic response in transforming growth factor-β1 (TGF-β1)-stimulated mouse renal proximal tubular epithelial cells (mPTCs). Moreover, impaired cellular metabolism was reported as a crucial pathogenic factor in CKD. By metabolomics analysis, we found that KD025 restored the metabolic disturbance, including the impaired glutathione metabolism in TGF-β1-stimulated tubular epithelial cells. Consistently, KD025 increased antioxidative stress enzymes and nuclear erythroid 2-related factor 2 (Nrf2) in fibrotic models. In addition, KD025 decreased the infiltration of macrophages and inflammatory response in fibrotic kidneys and blunted the activation of macrophages in vitro. In conclusion, inhibition of ROCK2 may serve as a potential novel therapy for renal tubulointerstitial fibrosis in CKD.

scholarly journals Inhibition of fibroblast growth factor-inducible 14 (Fn14) attenuates experimental tubulointerstitial fibrosis and profibrotic factor expression of proximal tubular epithelial cells

2020 ◽  
Author(s):  
Mai Luo ◽  
Mengmeng Liu ◽  
Wei Liu ◽  
Xiao Cui ◽  
Siyue Zhai ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epithelial Cells ◽  
Fibroblast Growth Factor ◽  
Interstitial Fibrosis ◽  
Tubulointerstitial Fibrosis ◽  
Fibroblast Growth ◽  
Tubular Epithelial Cells ◽  
Matrix Deposition ◽  
Proximal Tubular Epithelial Cells ◽  
Proximal Tubular

Abstract As a proinflammatory cytokine, tumor necrosis factor-like weak inducer of apoptosis (TWEAK) participates in the progression of renal fibrosis by engaging its receptor, fibroblast growth factor-inducible 14 (Fn14). However, the effect of Fn14 inhibition on tubular epithelial cell-mediated tubulointerstitial fibrosis remains unclear. This study was designed to elucidate the role of TWEAK/Fn14 interaction in the development of experimental tubulointerstitial fibrosis as well as the protective effect of Fn14 knockdown on proximal tubular epithelial cells. A murine model of unilateral ureteral obstruction was constructed in both wild-type and Fn14-deficient BALB/c mice, followed by observation of the tubulointerstitial pathologies. Fn14 deficiency ameliorated the pathological changes, including inflammatory cell infiltration and cell proliferation, accompanied by reduced production of profibrotic factors and extracellular matrix deposition. In vitro experiments showed that TWEAK dose-dependently enhanced the expressions of collagen I, fibronectin, and α-smooth muscle actin in proximal tubular epithelial cells. Interestingly, TWEAK also upregulated the expression levels of Notch1/Jagged1. Fn14 knockdown and Notch/Jagged1 inhibition also mitigated the effect of TWEAK on these cells. In conclusion, TWEAK/Fn14 signals contributed to tubulointerstitial fibrosis by acting on proximal tubular epithelial cells. Fn14 inhibition might be a therapeutic strategy for protecting against renal interstitial fibrosis.

FcRn-mediated transcytosis of immunoglobulin G in human renal proximal tubular epithelial cells

2002 ◽  
Vol 282 (2) ◽  
pp. F358-F365 ◽  
Author(s):  
Noriyoshi Kobayashi ◽  
Yusuke Suzuki ◽  
Toshinao Tsuge ◽  
Ko Okumura ◽  
Chisei Ra ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Proximal Tubules ◽  
Transepithelial Transport ◽  
Dependent Manner ◽  
Tubular Epithelial Cells ◽  
Human Igg ◽  
Proximal Tubular Epithelial Cells ◽  
Proximal Tubular ◽  
Ph Dependent ◽  
Renal Proximal Tubular

In the kidney, proteins filtered through glomeruli are reabsorbed by endocytosis along the proximal tubules to avoid renal loss of large amounts of proteins. Recently, neonatal Fc receptor (FcRn), which is involved in the transport of IgG across several epithelial and endothelial cells, was reported to be expressed in renal proximal tubular epithelial cells (RPTECs). However, there has been no direct evidence for receptor-mediated endocytosis of IgG in human RPTECs. To explore physiological roles of FcRn in the proximal tubules, we used the human RPTECs to examine IgG transport. FcRn was expressed in RPTECs and physically associated with β2-microglobulin, preserving the capacity of specific pH-dependent IgG binding. Human IgG was bound to the cell surface of RPTECs in a pH-dependent manner. The human IgG transport assay revealed that receptor-mediated transepithelial transport of intact IgG in RPTECs is bidirectional and that it requires the formation of acidified intracellular compartments. With the use of double immunofluorescence, the internalized human IgG was marked in cytoplasm of RPTECs and colocalized with FcRn. These data define the mechanisms of FcRn-associated IgG transport in RPTEC monolayers. It was suggested that the intact pathway for human IgG transepithelial transport may avoid lysosomal degradation of IgG.

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