Blockade of Autophagy Prevents the Development and Progression of Peritoneal Fibrosis

Abstract

Peritoneal fibrosis (PF) is a major cause of ultrafiltration failure in long-term peritoneal dialysis (PD) patients. Nevertheless, limited measures have been shown to be effective for the prevention and treatment of PF. Some views reveal that activation of autophagy ameliorates PF but others demonstrate that autophagy promotes PF. It is obvious that the role of autophagy in PF is controversial and further studies are needed. Here, we investigated the role of autophagy in rat models of PF and damaged cultured human peritoneal mesothelial cells (HPMCs). Autophagy was highly activated in fibrotic peritoneum from two PF rat models induced by 4.25% peritoneal dialysate fluid (PDF) and 0.1% chlorhexidine gluconate (CG). Blockade of autophagy with 3-MA effectively prevented PF in both models and reversed epithelial to mesenchymal transition (EMT) by down-regulating TGF-β/Smad3 signaling pathway and downstream nuclear transcription factors Slug and Snail. Treatment with 3-MA also inhibited activation of EGFR/ERK1/2 signaling pathway during PF. Moreover, 3-MA prominently decreased STAT3/NF-κB-mediated inflammatory response and macrophage infiltration, and prevented peritoneal angiogenesis through downregulation of β-catenin signal. In addition, TGF-β1 stimulation up-regulated autophagic activity as evidenced by the increased autophagosome in vitro. Exposure of HPMCs to TGF-β1 resulted in the induction of EMT and activation of TGF-β/Smad3, EGFR/ERK1/2 signaling pathways. Treatment with 3-MA blocked all these responses. In addition, delayed administration of 3-MA was effective in reducing EMT induced by TGF-β1. Taken together, our study indicated that autophagy might promote PF and 3-MA had anti-fibrosis effect in vivo and in vitro. These results suggest that autophagy could be a potential target on PF therapy for clinical patients with long-term PD.

Pharmacologic Inhibition of Histone Deacetylase 6 Prevents the Progression of Chlorhexidine Gluconate-Induced Peritoneal Fibrosis by Blockade of M2 Macrophage Polarization

“…Immunohistochemical and immunofluorescence staining were carried out according to the procedure described in our previous study ( 32 , 33 ). FFPE sections (3 μm) were rehydrated and incubated with primary antibodies against α-SMA (1:100, ab5694, Abcam), Twist (1:100, ab175430, Abcam), HDAC6 (1:100, A11259, ABclonal), CD163 (1:100, GB11340-1, Servicebio), Collagen I (1:400, GB11022-3, Servicebio), CD68 (1:100, sc-20060, Santa Cruz Biotechnology) and Arginase-1 (1:100, #93668, Cell Signaling Technology), and then secondary antibodies (Invitrogen).…”

Novel Aspects of the Immune Response Involved in the Peritoneal Damage in Chronic Kidney Disease Patients under Dialysis

“…In long-term PD, autophagy promotes fibrosis and apoptosis in the peritoneum [ 184 ]. In two different murine models of PDFs and CG damage, autophagy was found highly activated [ 185 ]. In these models, autophagy inhibition with 3-methyladenine (3-MA) successfully prevented peritoneal damage, noted by downregulation of TGF-β/SMAD signaling and the EMT transcription factors Slug and Snail, repressed activation of epidermal growth factor receptor (EGFR)/extracellular signal-regulated protein kinases ½ (ERK1/2) signaling pathway, decreased STAT3/NF-κB-mediated inflammatory response and macrophage infiltration, and prevented β-catenin-mediated peritoneal angiogenesis [ 185 ].…”

Blockade of Autophagy Prevents the Progression of Hyperuricemic Nephropathy Through Inhibiting NLRP3 Inflammasome-Mediated Pyroptosis

“…Autophagy plays an important role in maintaining the homeostasis, and it can regulate the development and differentiation of specific cells, such as adipocytes and lymphocytes ( 11 ). However, studies have reported that autophagy is also involved in pathological mechanisms ( 12 , 13 ). Using autophagy inhibitor 3-methyladenine (3-MA), our previous research has indicated that inhibition of autophagy alleviated HN in an adenine (0.1 g/kg) and potassium oxonate (1.5 g/kg)-induced rat model and an in vitro model of uric acid stimulated cultured rat renal interstitial fibroblasts (NRK-49F).…”