title: Toll-like receptor 4 signaling in dysfunction of cardiac microvascular endothelial cells under hypoxia/reoxygenation.
abstract: OBJECTIVE
  This study was designed to detect the role of Toll-like receptor 4 (TLR4) signaling in the dysfunction of cardiac microvascular endothelial cells (CMECs) after hypoxia/reoxygenation (H/R).
  
  
  METHODS
  The cell viability of CMECs was measured by MTT assay. The migration of CMECs was detected by cell scratch wound assay. The expressions of TLR4, nuclear factor-kappa B (NF-κB) and eNOS were analyzed by Western blot. Secretions of nitric oxide (NO) and tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) were determined by NO detection kit and ELISA.
  
  
  RESULTS
  Lipopolysaccharide (LPS) incubation increased the expressions of TLR4, NF-κB, IL-6 and TNF-α in CMECs (P < 0.05 vs. control). The CMECs after H/R injury had impaired cell viability (P < 0.01 vs. control) and migration ability (P < 0.05 vs. control). Moreover, the expressions of TLR4, NF-κB, IL-6 and TNF-α were elevated after H/R in CMECs (P < 0.01 vs. control), while NO and the eNOS expression were significantly decreased. In contrast, administration of the TLR4-neutralizing antibody MTS510 prior to H/R injury down-regulated the expressions of IL-6 and TNF-α and attenuated the dysfunction of CMECs.
  
  
  CONCLUSIONS
  TLR4 and its signaling components can be activated by LPS and H/R in CMECs. Blocking the TLR4 signal pathway before H/R injury attenuates CMEC dysfunction.
authors.affiliation: Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032 Shaanxi, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Zhang
authors.forename: Weijie
authors.initials: W
authors.lastname: Li
authors.forename: Dongdong
authors.initials: D
authors.lastname: Sun
authors.forename: Li
authors.initials: L
authors.lastname: Zhao
authors.forename: Rongqing
authors.initials: R
authors.lastname: Zhang
authors.forename: Yabin
authors.initials: Y
authors.lastname: Wang
authors.forename: Xuan
authors.initials: X
authors.lastname: Zhou
authors.forename: Haichang
authors.initials: H
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Cao
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology* / Q000503:physiopathology*; D006321:Heart / Q000033:anatomy & histology*; D000860:Hypoxia / Q000503:physiopathology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008833:Microcirculation; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015424:Reperfusion; D015398:Signal Transduction / Q000502:physiology*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*
chemical_list: D008070:Lipopolysaccharides; D051197:Toll-Like Receptor 4; D052250:Nitric Oxide Synthase Type III