title: Yes-associated protein (YAP) signaling regulates lipopolysaccharide-induced tissue factor expression in human endothelial cells.
abstract: BACKGROUND
  Sepsis-induced acute lung injury (ALI) is characterized by fibrin deposition, which indicates the local activation of coagulation. Tissue factor (TF), expressed in the pulmonary microvasculature, acts as a critical initiator of blood coagulation and ALI in sepsis. The molecular mechanism of lipopolysaccharide (LPS)-induced TF expression in endothelial cells (ECs), however, has not been determined. In this study, we implicate the Rho-associated protein kinase (ROCK)/Yes associated protein (YAP)/early growth response (Egr-1) signaling pathway in LPS-induced TF expression in vitro and in sepsis-induced ALI in vivo.
  
  
  METHODS
  Human umbilical vein ECs incubated with LPS were pretreated with or without the ROCK inhibitor Y-27632, a YAP small, interfering RNA (siRNA) and an Egr-1 siRNA. ROCK, YAP and Egr-1 signaling-induced protein expression was investigated by Western blot. The LPS-induced activation of YAP was analyzed by an immunofluorescent assay. Furthermore, we intratracheally injected YAP siRNA to assess septic ALI in mice by hematoxylin and eosin staining.
  
  
  RESULTS
  LPS rapidly induced ROCK activation and increased TF expression in ECs. LPS caused YAP shuttling into the nuclei of ECs and combined with Egr-1 via the activation of ROCK. Furthermore, the LPS-mediated TF expression increase was prevented by ROCK inactivation, YAP knockdown and Egr-1 depletion, suggesting that LPS-induced TF expression is closely associated with the ROCK/YAP/Egr-1 signaling pathway in ECs. Finally, an intratracheal injection of YAP siRNA relieved lung injury in septic mice.
  
  
  CONCLUSIONS
  This study not only suggests that ROCK/YAP/Egr-1 signaling regulates TF expression after stimulation with LPS in ECs, but it also indicates that LPS-induced activation of YAP signaling plays an important role in septic ALI in mice. Our findings provide a new insight into the pathogenic mechanism of TF expression, which is closely linked to septic ALI, and YAP signaling is considered to be a novel target for therapeutic intervention under septic conditions.
authors.affiliation: Department of Burn and Plastic Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Yi
authors.affiliation: Department of Burn and Plastic Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Huang
authors.affiliation: Department of Burn and Plastic Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Guo
authors.affiliation: Department of Burn and Plastic Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Zengding
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Department of Burn and Plastic Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Dou
authors.affiliation: Department of Burn and Plastic Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China. Electronic address: friendshiper@live.cn.
authors.forename: Jingning
authors.initials: J
authors.lastname: Huan
mesh_terms: D055371:Acute Lung Injury / Q000209:etiology / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D018797:Cell Cycle Proteins; D051766:Early Growth Response Protein 1 / Q000378:metabolism*; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism*; D006801:Humans; D008070:Lipopolysaccharides; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010750:Phosphoproteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018805:Sepsis / Q000150:complications*; D015398:Signal Transduction; D013925:Thromboplastin / Q000378:metabolism*; D014157:Transcription Factors; D000091102:YAP-Signaling Proteins; D054460:rho-Associated Kinases / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015415:Biomarkers; D018797:Cell Cycle Proteins; C497325:EGR1 protein, human; D051766:Early Growth Response Protein 1; D008070:Lipopolysaccharides; D010750:Phosphoproteins; D014157:Transcription Factors; D000091102:YAP-Signaling Proteins; C088374:YAP1 protein, human; C486223:Yap1 protein, mouse; D013925:Thromboplastin; D054460:rho-Associated Kinases