Sonic Hedgehog Signaling: Evidence for Its Protective Role in Endotoxin Induced Acute Lung Injury in Mouse Model

• Published in: PloS one Vol. 10; no. 11; p. e0140886
• Main Authors: Chen, Xing, Jin, Yuting, Hou, Xiaoming, Liu, Fengqin, Wang, Yulin
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 06.11.2015; Public Library of Science (PLoS)
• Subjects: Acute Lung Injury - chemically induced; Acute Lung Injury - metabolism; Acute Lung Injury - prevention & control; Alveoli; Angiogenesis; Animal tissues; Animals; Blotting, Western; Chronic obstructive pulmonary disease; Cytokines; Disease; Disease Models, Animal; Endotoxins - toxicity; Gene expression; Gene Expression Regulation - drug effects; Gli1 protein; Growth factors; Hedgehog protein; Hedgehog Proteins - genetics; Hedgehog Proteins - metabolism; Hospitals; Immunoenzyme Techniques; Injection; Injuries; Injury analysis; Ischemia; Lipopolysaccharides; Lipopolysaccharides - toxicity; Lungs; Male; Mice; Mice, Inbred BALB C; Mortality; Patched protein; Pediatrics; Polymerase chain reaction; Proteins; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; Rodents; Septum; Signal transduction; Signal Transduction - drug effects; Signaling; Stem cells; Studies; Transcription factors; Tumor necrosis factor-α
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0140886

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. 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. 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. 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.