title: Sonic hedgehog signalling pathway regulates apoptosis through Smo protein in human umbilical vein endothelial cells.
abstract: OBJECTIVE
  The aim of this study was to investigate the expression of smoothened protein (Smo), a sonic hedgehog (Shh) signalling component, in synovium of RA and its role in the survival and apoptosis of endothelial cells.
  
  
  METHODS
  The expression of Smo pxrotein in RA synovial tissue was examined by immunohistochemistry. Real-time PCR and western blotting techniques were employed to measure the expression of Shh signalling components in EA.hy926 endothelial cells exposed to TNF-α in the presence or absence of cyclopamine (a Smo-specific antagonist). Lastly, the effect of cyclopamine and Smo small interfering RNA on apoptosis induced by TNF-α and actinomycin D (ActD) was determined.
  
  
  RESULTS
  We found that Smo was highly expressed in synovial tissues of RA, especially in endothelial cells, compared with the trauma group. TNF-α significantly increased the expression of Shh signalling components in EA.hy926 endothelial cells, while cyclopamine decreased the expression of Shh signalling components. EA.hy926 endothelial cells treated with various concentrations of cyclopamine (2-8 μmol/l) showed a significant decrease in cell viability and cell survival rate, and an increase in the rate of cell apoptosis compared with endothelial cells treated with TNF-α and ActD (P < 0.05). EA.hy926 endothelial cells transfected with Smo-siRNA also showed a lower cell survival rate and higher apoptotic rate, compared with cells in the control group (P < 0.05).
  
  
  CONCLUSIONS
  The Shh signalling pathway plays a role in regulating endothelial cell apoptosis in a Smo-dependent manner.
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, The 3rd Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China.
authors.forename: Shang-Ling
authors.initials: SL
authors.lastname: Zhu
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, The 3rd Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China.
authors.forename: Min-Qi
authors.initials: MQ
authors.lastname: Luo
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, The 3rd Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China.
authors.forename: Wei-Xiang
authors.initials: WX
authors.lastname: Peng
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, The 3rd Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China.
authors.forename: Qiu-Xia
authors.initials: QX
authors.lastname: Li
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, The 3rd Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China.
authors.forename: Zhi-Ying
authors.initials: ZY
authors.lastname: Feng
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, The 3rd Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China.
authors.forename: Zhao-Xia
authors.initials: ZX
authors.lastname: Li
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, The 3rd Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China.
authors.forename: Ming-Xia
authors.initials: MX
authors.lastname: Wang
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, The 3rd Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China.
authors.forename: Xiao-Xue
authors.initials: XX
authors.lastname: Feng
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, The 3rd Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, The 3rd Affiliated Hospital, Sun Yat-Sen University, Guangzhou 510630, China jianlin_h@163.com.
authors.forename: Jian-Lin
authors.initials: JL
authors.lastname: Huang
mesh_terms: D000328:Adult; D017209:Apoptosis / Q000502:physiology*; D001172:Arthritis, Rheumatoid / Q000378:metabolism*; D015153:Blotting, Western; D016022:Case-Control Studies; D002470:Cell Survival / Q000502:physiology; D003609:Dactinomycin / Q000494:pharmacology; D005260:Female; D005434:Flow Cytometry; D053823:Hedgehog Proteins / Q000235:genetics; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D034741:RNA, Small Interfering / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D000072086:Smoothened Receptor; D013583:Synovial Membrane / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014704:Veratrum Alkaloids / Q000494:pharmacology
chemical_list: D053823:Hedgehog Proteins; D034741:RNA, Small Interfering; D043562:Receptors, G-Protein-Coupled; C491023:SMO protein, human; D000072086:Smoothened Receptor; D014409:Tumor Necrosis Factor-alpha; D014704:Veratrum Alkaloids; D003609:Dactinomycin; C000541:cyclopamine
keywords: apoptosis; endothelial cells; rheumatoid arthritis; smoothened protein; sonic hedgehog signalling pathway