title: Role of S100A1 in hypoxia-induced inflammatory response in cardiomyocytes via TLR4/ROS/NF-κB pathway.
abstract: OBJECTIVE
  S100A1 plays a crucial role in hypoxia-induced inflammatory response in cardiomyocytes. However, the role of S100A1 in hypoxia-induced inflammatory response in cardiomyocytes is still unknown.
  
  
  METHODS
  enzyme-linked immunosorbent assay (ELISA) was performed for the determination of inflammatory cytokines. Immunocytochemistry and immunofluorescence, Western blot analysis and Real-time polymerase chain reaction (RT-PCR) were conducted to assess protein or mRNA expressions. Fluorogenic probe dihydroethidium (DHE) was used to evaluate the generation of reactive oxygen species (ROS) while Hoechst 33342 staining for apoptosis. Small interfering RNA (siRNA) for S100A1 was used to evaluate the role of S100A1.
  
  
  RESULTS
  The levels of ROS and inflammatory cytokine including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and IL-8 in H9c2 cells were increased remarkably by hypoxia. However, IL-37 protein or mRNA levels were decreased significantly. Both Toll-like receptor 4 (TLR4) inhibitor Ethyl (6R)-6-[N-(2-Chloro-4fluorophenyl)sulfamoyl]cyclohex-1-ene-1-carboxylate (TAK-242) treatment or siRNA S100A1 downregulated TLR4 expression and inflammatory cytokine level and mRNA in H9c2 cells, as well as weakening ROS and phospho-p65 Nuclear factor (NF)-κB levels. Further, S100A1 treatment significantly reduced TNF-α protein or mRNA level whereas enhanced IL-37 protein or mRNA level, and could attenuate ROS and phospho-p65 NF-κB levels.
  
  
  CONCLUSIONS
  Our results demonstrate that S100A1 can regulate the inflammatory response and oxidative stress in H9C2 cells via TLR4/ROS/NF-κB pathway. These findings provide an interesting strategy for protecting cardiomyocytes from hypoxia-induced inflammatory response.
authors.affiliation: Department of Cardiology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Jiangkun
authors.initials: J
authors.lastname: Yu
authors.affiliation: Department of Cardiology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Yanyu
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of Cardiology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Yapeng
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Cardiology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Xiao
authors.affiliation: Department of Cardiology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Xing
authors.affiliation: Department of Cardiology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Yanshen
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Cardiology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
authors.forename: Leiming
authors.initials: L
authors.lastname: Wu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002460:Cell Line; D015536:Down-Regulation / Q000502:physiology; D000860:Hypoxia / Q000378:metabolism*; D007249:Inflammation / Q000378:metabolism*; D007378:Interleukins / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D009418:S100 Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D051197:Toll-Like Receptor 4 / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D007378:Interleukins; D016328:NF-kappa B; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D009418:S100 Proteins; C110294:S100A1 protein; C495347:Tlr4 protein, rat; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha
keywords: S100A1; TLR4; cardiomyocytes; hypoxia; inflammatory response