title: [Mechanism of serotonin-promoted synthesis of osteoblast type I collagen].
abstract: OBJECTIVE
  To explore the mechanism of serotonin-promoted osteoblast differentiation.
  
  
  METHODS
  Expression levels of collagen I and lysyl oxidase (LOX) in osteoblast were measured by RT-PCR after treated by (50, 100, 200 and 400 ng/L) serotonin. LOX siRNA effect was measured by Western blot, and protein levels of collagen I were determined by ELISA after treated by serotonin. Expression levels of Smad2 and Smad3 in osteoblasts were also measured by RT-PCR after treated by serotonin.Moreover, expression levels of LOX were measured by RT-PCR after Smad3 was knockout.
  
  
  RESULTS
  Serotonin promoted collagen I and LOX expression. The expression level of collagen I was significantly decreased by LOX siRNA. Furthermore, serotonin up-regulated the expression of Smad2 and Smad3 in osteoblasts, and the expression level of LOX was inhibited by Smad3 siRNA.
  
  
  CONCLUSIONS
  Serotonin promoted collagen I expression by activating Smads signaling pathway and up-regulating the LOX expression.
authors.affiliation: Department of Traumatic Orthopedic, Henan Province Hospital of Traditional Chinese Medicine, Zhengzhou 450002, China.
authors.forename: Yujing
authors.initials: Y
authors.lastname: Cao
authors.affiliation: E-mail: youhua_huang@163.com; School of Basic Medicine, Henan University of Traditional Chinese Medicine, Zhengzhou 450002, China.
authors.forename: Cuitian
authors.initials: C
authors.lastname: Lyu
mesh_terms: D015153:Blotting, Western; D002454:Cell Differentiation; D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism*; D006801:Humans; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism*; D008249:Protein-Lysine 6-Oxidase / Q000378:metabolism; D034741:RNA, Small Interfering; D012701:Serotonin / Q000494:pharmacology*; D015398:Signal Transduction; D051899:Smad2 Protein / Q000378:metabolism; D051900:Smad3 Protein / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D024042:Collagen Type I; D034741:RNA, Small Interfering; C497782:SMAD2 protein, human; C497790:SMAD3 protein, human; D051899:Smad2 Protein; D051900:Smad3 Protein; D012701:Serotonin; D008249:Protein-Lysine 6-Oxidase