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Purpose: This study aimed to evaluate the potential of astragalus polysaccharide (APS) pretreatment in enhancing the homing and anti-peritoneal fibrosis capabilities of bone marrow mesenchymal stromal cells (BMSCs) and to elucidate the underlying mechanisms., Methods: Forty male Sprague-Dawley rats were allocated into four groups: control, peritoneal dialysis fluid (PDF), PDF + BMSCs, and PDF +  APS BMSCs (APS-pre-treated BMSCs). A peritoneal fibrosis model was induced using PDF. Dil-labeled BMSCs were administered intravenously. Post-transplantation, BMSC homing to the peritoneum and pathological alterations were assessed. Stromal cell-derived factor-1 (SDF-1) levels were quantified via enzyme-linked immunosorbent assay (ELISA), while CXCR4 expression in BMSCs was determined using PCR and immunofluorescence. Additionally, a co-culture system involving BMSCs and peritoneal mesothelial cells (PMCs) was established using a Transwell setup to examine the in vitro effects of APS on BMSC migration and therapeutic efficacy, with the CXCR4 inhibitor AMD3100 deployed to dissect the role of the SDF-1/CXCR4 axis and its downstream impacts., Results: In vivo and in vitro experiments confirmed that APS pre-treatment notably facilitated the targeted homing of BMSCs to the peritoneal tissue of PDF-treated rats, thereby amplifying their therapeutic impact. PDF exposure markedly increased SDF-1 levels in peritoneal and serum samples, which encouraged the migration of CXCR4-positive BMSCs. Inhibition of the SDF-1/CXCR4 axis through AMD3100 application diminished BMSC migration, consequently attenuating their therapeutic response to peritoneal mesenchyme-to-mesothelial transition (MMT). Furthermore, APS upregulated CXCR4 expression in BMSCs, intensified the activation of the SDF-1/CXCR4 axis's downstream pathways, and partially reversed the AMD3100-induced effects., Conclusion: APS augments the SDF-1/CXCR4 axis's downstream pathway activation by increasing CXCR4 expression in BMSCs. This action bolsters the targeted homing of BMSCs to the peritoneal tissue and amplifies their suppressive influence on MMT, thereby improving peritoneal fibrosis., (© 2024. The Author(s).)

Background/Aims: The epithelial-to-mesenchymal transition (EMT) of peritoneal mesothelial cells (PMCs) is a crucial event in the induction of peritoneal fibrosis (PF), in which canonical Wnt/β-catenin signaling participates. Smads signaling is reported to interact with β-catenin and synergistically regulates EMT. This study was aimed to reveal the effect of Astragalus on β-catenin in EMT of PMCs. Methods: To obtain the role of β-catenin in EMT, gene transfer into HMrSV5 cell line and rats has been achieved. After Astragalus treatment, EMT markers and signaling pathway-related indicators were detected by western blotting, immunofluorescence, immunohistochemistry, immunoprecipitation and real time-PCR. Results: β-catenin knockdown suppressed EMT of HMrSV5 cells. Astragalus alleviated EMT of PMCs characterized by increased E-cadherin and decreased α-SMA and Vimentin. In rat model of peritoneal dialysis (PD), Astragalus attenuated peritoneal thickening and fibrosis. Astragalus down-regulated β-catenin by stabilizing the Glycogen synthase kinase-3β (GSK-3β)/β-catenin complex and further inhibited the nuclear translocation of β-catenin. Meanwhile, Astragalus down-regulated β-catenin by enhancing Smad7 expression. Silencing Smad7 antagonized the EMT-inhibitory effect of Astragalus. Conclusion: Astragalus inhibits EMT of PMCs by down-regulating β-catenin. The modulation of β-catenin in peritoneum can be a novel tool to prevent PF. [ABSTRACT FROM AUTHOR]

Background/Aims: To investigate the effect of Astragaloside IV (AS-IV) on the regulation of the TGF-β1/Smad signaling pathway in peritoneal mesothelial cells with an epithelial-to-mesenchymal transition (EMT). Methods: EMT of human peritoneal mesothelial cells (HMrSV5) was induced using 2 ng/ml TGF-β1. Cells were randomly divided into a vehicle group, a vehicle group with AS-IV, a TGF-β1 treated group, and a TGF-β1 treated group receiving varied doses of AS-IV or NAC. Real-time quantitative PCR and western blot were used to detect the expression of genes and proteins associated with the TGF-β1/Smad signaling pathway and EMT. DCFH-DA was used to detect the generation of ROS in HMrSV5 cells, and a transwell migration assay was used to verify the capacity of AS-IV to inhibit EMT in HMrSV5 cells. Lentiviruses were used as carriers for the overexpression or knockdown of the Smad7 gene. Results: Expression levels of E-cadherin (epithelial marker) was decreased and vimentin, α-SMA (EMT markers) and collagen I (extracellular matrix protein) phospho-Smad2/3, Snail1 and Snail2 was increased significantly in the TGF-β1-treated HMrSV5 cells. AS-IV was associated with downregulated expression of vimentin and phospho-Smad2/3 in a dose-dependent manner, while the expression of Smad7 increased. Silenced or forced expression of Smad7 verified its role in the inhibitory effect of AS-IV on TGF-β1-induced EMT in HMrSV5 cells. Conclusion: AS-IV effectively promotes the upregulation of Smad7 in the TGF-β1/Smad signaling pathway during the EMT of HMrSV5 cells, indicating its potential therapeutic effect for the control of PF. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]