title: Sonic Hedgehog Signaling: Evidence for Its Protective Role in Endotoxin Induced Acute Lung Injury in Mouse Model.
abstract: OBJECTIVE
  To investigate the protective role of the sonic hedgehog (SHH) signaling associated with a lipopolysaccharide (LPS)-induced acute lung injury (ALI) in a mouse model.
  
  
  METHODS
  Male BALB/c mice were randomly divided into four groups: control, LPS, LPS-cyclopamine group and cyclopamine group. ALI was induced by LPS ip injection (5 mg/kg). The sonic hedgehog inhibitor cyclopamine (50 mg/kg) was given to the LPS-cyclopamine group at 30 min after LPS injection as well as normal mice as control. Lung injury was observed histologically in hematoxylin and eosin (HE) stained tissue sections, semi-quantified by lung tissue injury score, and the lung tissue mass alteration was measured by wet to dry weight ratio (W/D). mRNA expression levels of TNF-α, SHH, Patched (PTC) and GLI1 in lung tissue were studied with real time quantitative PCR (RT-PCR), while the protein expression of SHH and GLI1 was determined by western blot analysis.
  
  
  RESULTS
  Lung tissue injury score, thickness of alveolar septa, W/D, and TNF-α mRNA expression levels were significantly higher in the ALI mice than the normal mice (P<0.05). The mRNA expression levels of SHH, PTC, and GLI1 in the ALI mice were significantly higher at 12h and 24h after LPS injection, but not at the 6h time point. Protein production of SHH and GLI1 at 6h, 12h, and 24h in the lungs of ALI mice significantly increased, in a time-dependent manner, compared with that in normal mice. Cyclopamine alone has no effect on pathological changes in normal mice. Intervention with cyclopamine in ALI mice led to a reduction in mRNA levels of SHH, PTC, and GLI1 as well as SHH and GLI1 protein levels; meanwhile, the pathological injury scores of lung tissues, thickness of alveolar septa, W/D, and mRNA expression levels of TNF-α increased compared with mice receiving LPS only.
  
  
  CONCLUSIONS
  The SHH signaling pathway was activated in response to LPS-induced ALI, and up-regulation of SHH expression could alleviate lung injury and be involved in the repair of injured lung tissue.
authors.affiliation: Department of Pediatrics, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, The People's Republic of China.
authors.forename: Xing
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Pediatrics, Shandong Provincial Qianfoshan Hospital, Jinan, Shandong, The People's Republic of China.
authors.forename: Yuting
authors.initials: Y
authors.lastname: Jin
authors.affiliation: Department of Pediatrics, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, The People's Republic of China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Hou
authors.affiliation: Department of Pediatrics, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, The People's Republic of China.
authors.forename: Fengqin
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Pediatrics, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, The People's Republic of China.
authors.forename: Yulin
authors.initials: Y
authors.lastname: Wang
mesh_terms: D055371:Acute Lung Injury / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control*; D000818:Animals; D015153:Blotting, Western; D004195:Disease Models, Animal; D004731:Endotoxins / Q000633:toxicity*; D005786:Gene Expression Regulation / Q000187:drug effects*; D053823:Hedgehog Proteins / Q000235:genetics / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D008070:Lipopolysaccharides / Q000633:toxicity; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D004731:Endotoxins; D053823:Hedgehog Proteins; D008070:Lipopolysaccharides; D012333:RNA, Messenger; C465570:Shh protein, mouse