title: Angiotensin II upregulates Toll-like receptor 4 and enhances lipopolysaccharide-induced CD40 expression in rat peritoneal mesothelial cells.
abstract: OBJECTIVE
  Activation of Toll-like receptor 4 (TLR4) in peritoneal mesothelial cells by endotoxin contributes to peritoneal inflammation and fibrosis. Here we investigated TLR4 expression induced by angiotensin II (Ang II) and functional consequences of nuclear factor-kappaB (NF-kappaB) activation and CD40 expression in rat peritoneal mesothelial cells (RPMCs).
  
  
  METHODS
  TLR4, CD40, tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6) were determined by reverse transcription polymerase chain reaction (RT-PCR) and TLR4, IkappaBalpha, phospho-IkappaBalpha, NF-kappaB p65, and phospho-NF-kappaB p65 were analyzed by Western blot. The intracellular distribution of NF-kappaB p65 was detected by immunofluorescence.
  
  
  RESULTS
  Treatment of RPMCs with Ang II resulted in an increase in the expression of TLR4 mRNA and protein levels. Preincubation of RPMCs with Ang II significantly increased lipopolysaccharide (LPS)-induced phospho-IkappaBalpha and phospho-NF-kappaB p65 protein (P < 0.05 vs. LPS alone) and CD40, TNF-alpha, and IL-6 mRNA levels (P < 0.05 vs. LPS alone). A significantly increased nuclear staining of NF-kappaB p65 in cells treated with Ang II plus LPS was also observed.
  
  
  CONCLUSIONS
  Ang II upregulates the expression of TLR4 by RPMCs, resulting in enhanced NF-kappaB signaling and induction of CD40, TNF-alpha, and IL-6 expression. Locally produced Ang II in the peritoneum may have an amplified role in LPS-induced peritoneal inflammation.
authors.affiliation: Department of Nephrology, The First Affiliated Hospital of Sun Yat-Sen University, 58 Zhongshan Road II, 510080 Guangzhou, People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wu
authors.forename: Xiao
authors.initials: X
authors.lastname: Yang
authors.forename: Yun-Fang
authors.initials: YF
authors.lastname: Zhang
authors.forename: Shu-Feng
authors.initials: SF
authors.lastname: Zhou
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: Xiu-Qing
authors.initials: XQ
authors.lastname: Dong
authors.forename: Jin-Jin
authors.initials: JJ
authors.lastname: Fan
authors.forename: Mei
authors.initials: M
authors.lastname: Liu
authors.forename: Xue-Qing
authors.initials: XQ
authors.lastname: Yu
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D019013:CD40 Antigens / Q000096:biosynthesis*; D004848:Epithelium / Q000187:drug effects; D015850:Interleukin-6 / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D008856:Microscopy, Fluorescence; D016328:NF-kappa B / Q000378:metabolism; D010537:Peritoneum / Q000166:cytology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051197:Toll-Like Receptor 4 / Q000187:drug effects*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D019013:CD40 Antigens; D015850:Interleukin-6; D008070:Lipopolysaccharides; D016328:NF-kappa B; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D000804:Angiotensin II