title: The Role of TLR4 in M1 Macrophage-Induced Epithelial-Mesenchymal Transition of Peritoneal Mesothelial Cells.
abstract: OBJECTIVE
  Peritoneal fibrosis is a frequent complication of peritoneal dialysis that follows inflammation. It is recognized that epithelial-mesenchymal transition (EMT) of peritoneal mesothelial cells (PMCs), plays a key role in fibrogenesis. However, the relationship between inflammatory macrophages and PMCs remains elusive. In this study, we investigated the effects of different polarized macrophages on EMT of HMrSV5 PMCs.
  
  
  METHODS
  Monocytes were polarized to M1/M2 macrophages before being added to HMrSV5 in direct or indirect contact. Morphological changes of HMrSV5 were observed and toll-like receptors 4 (TLR4) on macrophage surfaces was detected using flow cytometry. EMT markers and intracellular signals of HMrSV5 cells were assessed using real time-PCR and WB.
  
  
  RESULTS
  The typical epithelial cell morphology of HMrSV5 disappeared after co-culture with M1 macrophages and was accompanied by decreased E-cadherin and increased α-SMA, suggesting HMrSV5 undergo EMT. These effects depended on direct contact between the two cells, as indirect contact or co-culture with M2 macrophages had no effect. Intriguingly, we found TLR4 surface receptors were activated on sorted M1 cells in co-culture, and related signal adaptors, such as TRIF, were obviously upregulated.
  
  
  CONCLUSIONS
  Direct contact with M1 macrophages induces EMT of PMCs, during which TRIF-dependent TLR4 signaling pathway was activated.
authors.affiliation: First Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Shi
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.forename: Meixiao
authors.initials: M
authors.lastname: Sheng
authors.forename: Min
authors.initials: M
authors.lastname: Zheng
authors.forename: Manshu
authors.initials: M
authors.lastname: Yu
authors.forename: Lu
authors.initials: L
authors.lastname: Zhang
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity; D048430:Cell Shape; D018920:Coculture Techniques; D015536:Down-Regulation / Q000235:genetics; D058750:Epithelial-Mesenchymal Transition; D004848:Epithelium / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology; D006801:Humans; D008262:Macrophage Activation; D008264:Macrophages / Q000378:metabolism*; D009000:Monocytes / Q000166:cytology; D010537:Peritoneum / Q000166:cytology*; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000378:metabolism*; D015854:Up-Regulation / Q000235:genetics
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D015415:Biomarkers; C470409:TICAM1 protein, human; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4