title: The monocyte chemoattractant protein-1 (MCP-1)/CCR2 system is involved in peritoneal dialysis-related epithelial-mesenchymal transition of peritoneal mesothelial cells.
abstract: Epithelial-mesenchymal transition (EMT) of peritoneal mesothelial cells (PMCs) has a role in the process of peritoneal fibrosis (PF), a serious complication in peritoneal dialysis (PD) patients. Even though monocyte chemoattractant protein-1 (MCP-1) was demonstrated to directly increase extracellular matrix (ECM) synthesis, the role of the MCP-1/CCR2 system in PD-related EMT and ECM synthesis in cultured human PMCs (HPMCs) and in an animal model of PD has never been elucidated. In vitro, HPMCs were exposed to 5.6 mM glucose (NG), NG+MCP-1 (10 ng/ml) (NG+MCP-1), or 100 mM glucose (HG) with or without CCR2 inhibitor (RS102895) (CCR2i) or a dominant-negative mutant MCP-1-expressing lentivirus (LV-mMCP-1). In vivo, PD catheters were inserted into 60 Sprague-Dawley rats, and saline (Control, C) (N=30) or 4.25% PD solution (PD) (N=30) was infused for 4 weeks. Twenty rats from each group were treated with empty LV or LV-mMCP-1 intraperitoneally. Snail, E-cadherin, α-smooth muscle actin (α-SMA), and fibronectin protein expression in HPMCs and the peritoneum was evaluated by western blot analysis. Compared with NG cells, Snail, α-SMA, and fibronectin expression was significantly increased, while E-cadherin expression was significantly decreased in HPMCs exposed to HG and NG+MCP-1, and these changes were significantly abrogated by CCR2i (P<0.05). In addition, MCP-1-induced EMT was significantly attenuated by anti-TGF-β1 antibody. In PD rats, Snail and fibronectin expression was significantly increased in the peritoneum, whereas the ratios of E-cadherin/α-SMA protein expression were significantly decreased (P<0.05). The thickness of the peritoneum and the intensity of Masson's trichrome staining in the peritoneum were also significantly higher in PD rats than in C rats (P<0.05). These changes in PD rats were significantly abrogated by LV-mMCP-1. These findings suggest that the MCP-1/CCR2 system is directly involved in PD-related EMT and ECM synthesis and that this is mediated, at least in part, via TGF-β1.
authors.affiliation: Department of Internal Medicine, College of Medicine, Brain Korea 21, Severance Biomedical Science Institute, Yonsei University, Seoul, Korea.
authors.forename: Sun Ha
authors.initials: SH
authors.lastname: Lee
authors.forename: Hye-Young
authors.initials: HY
authors.lastname: Kang
authors.forename: Kyung Sik
authors.initials: KS
authors.lastname: Kim
authors.forename: Bo Young
authors.initials: BY
authors.lastname: Nam
authors.forename: Jisun
authors.initials: J
authors.lastname: Paeng
authors.forename: Seonghun
authors.initials: S
authors.lastname: Kim
authors.forename: Jin Ji
authors.initials: JJ
authors.lastname: Li
authors.forename: Jung Tak
authors.initials: JT
authors.lastname: Park
authors.forename: Dong Ki
authors.initials: DK
authors.lastname: Kim
authors.forename: Seung Hyeok
authors.initials: SH
authors.lastname: Han
authors.forename: Tae-Hyun
authors.initials: TH
authors.lastname: Yoo
authors.forename: Shin-Wook
authors.initials: SW
authors.lastname: Kang
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D058750:Epithelial-Mesenchymal Transition / Q000502:physiology*; D005109:Extracellular Matrix / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D010530:Peritoneal Dialysis / Q000009:adverse effects*; D056627:Peritoneal Fibrosis / Q000378:metabolism; D010537:Peritoneum / Q000166:cytology* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D054390:Receptors, CCR2 / Q000378:metabolism*; D015398:Signal Transduction; D053773:Transforming Growth Factor beta1 / Q000378:metabolism
chemical_list: C515334:CCR2 protein, human; D018932:Chemokine CCL2; D005353:Fibronectins; D054390:Receptors, CCR2; D053773:Transforming Growth Factor beta1; D005947:Glucose