Aberrant Wnt/Beta-Catenin Pathway Activation in Dialysate-Induced Peritoneal Fibrosis.
Guo Yuanyuan,Sun Lin,Xiao Li,Gou Rong,Fang Yudong,Liang Yan,Wang Ruiqiang,Li Ningjun,Liu Fuyou,Tang Lin
Frontiers in pharmacology
Peritoneal dialysis (PD)-associated peritoneal fibrosis is a chronic progress which induces ultrafiltration failure. It remains a challenge to prevent the progression of PD-associated fibrosis in clinic practice. Wnt/β-catenin pathway plays important role in many severe fibrotic diseases, here we investigated its contribution to the development of peritoneal damage. We isolated mesothelial cells (MC) from the effluent of PD patients and found that the expressions of Wnt1, Wnt5a, β-catenin, and LEF1 were increased in patients with more than 1-year PD compared with patients who just started with PD (<1 month). The elevated expressions of Wnts and β-catenin were accompanied with changes in the expressions of E-cadherin, α-SMA, COL-I, and FN mRNA and proteins, which are known related to mesothelial-mesenchymal transition (MMT). In addition, treatment with high glucose significantly increased the expression of Wnt1, Wnt5a, β-catenin, and LEF1 as well as the expression of α-SMA, COL-I, and FN in human peritoneal mesothelial cells (HPMC), whereas the expression of E-cadherin was reduced. Dickkopf-1 (DKK-1) is an endogenous inhibitor of Wnt/β-catenin signaling. Overexpression of DKK1 transgene significantly decreased the expression of β-catenin and attenuated the process of MMT as indicated by the decreased expression of α-SMA, COL-I, and FN and the increased expression of E-cadherin. Furthermore, TGF-β1 treatment significantly activated the Wnt/β-catenin pathway in HPMCs, while DKK1 blocked the TGF-β1-induced Wnt signaling activation and significantly inhibited the process of MMT. These data suggest that the canonical Wnt/β-catenin pathway plays an important role in the MMT and fibrosis induced by PD.
Loss of JNK-Associated Leucine Zipper Protein Promotes Peritoneal Dialysis-Related Peritoneal Fibrosis.
Kidney diseases (Basel, Switzerland)
Background:Peritoneal dialysis-related peritoneal fibrosis is the leading cause of peritoneal ultrafiltration failure. Multitude factors and pathological processes have been implicated in peritoneal fibrosis development and progression, whereas the intrinsic anti-fibrotic mechanism has rarely been explored. JNK-associated leucine zipper protein (JLP) has been recently found possessing powerful anti-fibrotic merits of overall antagonizing TGF-β-induced profibrotic effects. Objectives:We wondered whether JLP is expressed in the peritoneum, and if so, whether it exerts the anti-fibrotic effects similar to those in the kidney. Method:Here, we examined and confirmed JLP expression in peritoneum tissue of mice. Then, we established a peritoneal fibrosis model in wild-type and global deficient mice and observed the different effects of Jlp on peritoneal fibrosis progression. In vitro studies were performed on peritoneal mesothelial HMrSV5 cells with or without Jlp knockdown to investigate the underlying mechanism by which Jlp exerts anti-fibrotic effects. Results:We found that the expression of JLP decreased in a high-glucose peritoneal dialysis solution (HGPDS)-induced peritoneal fibrosis mouse model and in HGPDS-treated peritoneal mesothelial cell HMrSV5. JLP deletion exacerbated HGPDS-induced peritoneal fibrosis in peritoneal fibrosis mice, and knockdown of JLP resulted in an increased profibrotic response to HGPDS stimulation in HMrSV5 cells, which was associated with epithelial-to-mesenchymal transition, elevated autophagy, and apoptosis, as well as enhanced TGF-β1/Smad signaling activation. Conclusions:Our findings revealed a new anti-fibrotic factor of Jlp involved in peritoneal fibrosis induction and shed light on novel therapeutic targets in peritoneal ultrafiltration failure.
Asiaticoside inhibits TGF-β1-induced mesothelial-mesenchymal transition and oxidative stress via the Nrf2/HO-1 signaling pathway in the human peritoneal mesothelial cell line HMrSV5.
Cellular & molecular biology letters
BACKGROUND:Peritoneal fibrosis (PF) is a frequent complication caused by peritoneal dialysis (PD). Peritoneal mesothelial cells (PMCs), the first barrier of the peritoneum, play an important role in maintaining structure and function in the peritoneum during PD. Mesothelial-mesenchymal transition (MMT) and oxidative stress of PMCs are two key processes of PF. PURPOSE:To elucidate the efficacy and possible mechanism of asiaticoside inhibition of MMT and ROS generation in TGF-β1-induced PF in human peritoneal mesothelial cells (HPMCs). METHODS:MMT and ROS generation of HPMCs were induced by TGF-β1. To explain the anti-MMT and antioxidant role of asiaticoside, varied doses of asiaticoside, oxygen radical scavenger (NAC), TGF-β receptor kinase inhibitor (LY2109761) and Nrf2 inhibitor (ML385) were used separately. Immunoblots were used to detect the expression of signaling associated proteins. DCFH-DA was used to detect the generation of ROS. Transwell migration assay and wound healing assay were used to verify the capacity of asiaticoside to inhibit MMT. Immunofluorescence assay was performed to observe the subcellular translocation of Nrf2 and expression of HO-1. RESULTS:Asiaticoside inhibited TGF-β1-induced MMT and suppressed Smad signaling in a dose-dependent manner. Migration and invasion activities of HPMCs were decreased by asiaticoside. Asiaticoside decreased TGF-β1-induced ROS, especially in a high dose (150 μM) for 6 h. Furthermore, ML385 partly abolished the inhibitory effect of asiaticoside on MMT, ROS and p-Smad2/3. CONCLUSIONS:Asiaticoside inhibited the TGF-β1-induced MMT and ROS via Nrf2 activation, thus protecting the peritoneal membrane and preventing PF.