title: The hepatocyte growth factor-expressing character is required for mesenchymal stem cells to protect the lung injured by lipopolysaccharide in vivo.
abstract: BACKGROUND
  Acute respiratory distress syndrome (ARDS) is a life-threatening condition in critically ill patients. Recently, we have found that mesenchymal stem cells (MSC) improved the permeability of human lung microvascular endothelial cells by secreting hepatocyte growth factor (HGF) in vitro. However, the properties and functions of MSC may change under complex circumstances in vivo. Here, we sought to determine the role of the HGF-expressing character of MSC in the therapeutic effects of MSC on ARDS in vivo.
  
  
  METHODS
  MSC with HGF gene knockdown (MSC-ShHGF) were constructed using lentiviral transduction. The HGF mRNA and protein levels in MSC-ShHGF were detected using quantitative real-time polymerase chain reaction and Western blotting analysis, respectively. HGF levels in the MSC culture medium were measured by enzyme-linked immunosorbent assay (ELISA). Rats with ARDS induced by lipopolysaccharide received MSC infusion via the tail vein. After 1, 6, and 24 h, rats were sacrificed. MSC retention in the lung was assessed by immunohistochemical assay. The lung wet weight to body weight ratio (LWW/BW) and Evans blue dye extravasation were obtained to reflect lung permeability. The VE-cadherin was detected with inmmunofluorescence, and the lung endothelial cell apoptosis was assessed by TUNEL assay. The severity of lung injury was evaluated using histopathology. The cytokines and HGF levels in the lung were measured by ELISA.
  
  
  RESULTS
  MSC-ShHGF with markedly lower HGF expression were successfully constructed. Treatment with MSC or MSC carrying green fluorescent protein (MSC-GFP) maintained HGF expression at relatively high levels in the lung at 24 h. MSC or MSC-GFP decreased the LWW/BW and the Evans Blue Dye extravasation, protected adherens junction VE-cadherin, and reduced the lung endothelial cell apoptosis. Furthermore, MSC or MSC-GFP reduced the inflammation and alleviated lung injury based on histopathology. However, HGF gene knockdown significantly decreased the HGF levels without any changes in the MSC retention in the lung, and diminished the protective effects of MSC on the injured lung, indicating the therapeutic effects of MSC on ARDS were partly associated with the HGF-expressing character of MSC.
  
  
  CONCLUSIONS
  MSC restores lung permeability and lung injury in part by maintaining HGF levels in the lung and the HGF-expressing character is required for MSC to protect the injured lung.
authors.affiliation: Department of Critical Care Medicine, Zhongda Hospital, Southeast University School of Medicine, No.87 Dingjiaqiao Road, Nanjing, 210009, Jiansu, P.R. China.
authors.forename: Shuling
authors.initials: S
authors.lastname: Hu
authors.affiliation: Department of Critical Care Medicine, Zhongda Hospital, Southeast University School of Medicine, No.87 Dingjiaqiao Road, Nanjing, 210009, Jiansu, P.R. China.
authors.forename: Jinze
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Critical Care Medicine, Zhongda Hospital, Southeast University School of Medicine, No.87 Dingjiaqiao Road, Nanjing, 210009, Jiansu, P.R. China.
authors.forename: Xiuping
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Critical Care Medicine, Zhongda Hospital, Southeast University School of Medicine, No.87 Dingjiaqiao Road, Nanjing, 210009, Jiansu, P.R. China.
authors.forename: Airan
authors.initials: A
authors.lastname: Liu
authors.affiliation: Department of Critical Care Medicine, Zhongda Hospital, Southeast University School of Medicine, No.87 Dingjiaqiao Road, Nanjing, 210009, Jiansu, P.R. China.
authors.forename: Hongli
authors.initials: H
authors.lastname: He
authors.affiliation: Department of Critical Care Medicine, Zhongda Hospital, Southeast University School of Medicine, No.87 Dingjiaqiao Road, Nanjing, 210009, Jiansu, P.R. China.
authors.forename: Jingyuan
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Critical Care Medicine, Zhongda Hospital, Southeast University School of Medicine, No.87 Dingjiaqiao Road, Nanjing, 210009, Jiansu, P.R. China.
authors.forename: Qihong
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Department of Critical Care Medicine, Zhongda Hospital, Southeast University School of Medicine, No.87 Dingjiaqiao Road, Nanjing, 210009, Jiansu, P.R. China.
authors.forename: Songqiao
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Critical Care Medicine, Zhongda Hospital, Southeast University School of Medicine, No.87 Dingjiaqiao Road, Nanjing, 210009, Jiansu, P.R. China.
authors.forename: Ling
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Critical Care Medicine, Zhongda Hospital, Southeast University School of Medicine, No.87 Dingjiaqiao Road, Nanjing, 210009, Jiansu, P.R. China.
authors.forename: Haibo
authors.initials: H
authors.lastname: Qiu
authors.affiliation: Department of Critical Care Medicine, Zhongda Hospital, Southeast University School of Medicine, No.87 Dingjiaqiao Road, Nanjing, 210009, Jiansu, P.R. China. yiyiyang2004@163.com.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
mesh_terms: D055371:Acute Lung Injury / Q000139:chemically induced / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D000818:Animals; D017209:Apoptosis; D001835:Body Weight; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D002199:Capillary Permeability; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D017228:Hepatocyte Growth Factor / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D016086:Lentivirus / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides; D008168:Lung / Q000378:metabolism / Q000473:pathology; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D061251:Primary Cell Culture; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction
chemical_list: C000610228:CDH1 protein, rat; D015820:Cadherins; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D049452:Green Fluorescent Proteins; D017228:Hepatocyte Growth Factor
keywords: Acute lung injury; Hepatic growth factor; Lung vascular permeability; Mesenchymal stem cell