title: Mechano-growth factor E peptide inhibits the differentiation and mineralization of osteoblasts.
abstract: OBJECTIVE
  To investigate the effects of mechano-growth factor E (MGF-E) peptide derived from an IGF-1 isoform on the differentiation and mineralization of osteoblasts.
  
  
  METHODS
  MGF-E peptide corresponding to the carboxy terminal 24 amino acid peptide of human MGF was synthesized. MGF-E (1 nM) peptide was then used to treat the pre-osteoblast line MC3T3-E1. At predetermined times, alkaline phosphatase (ALP) activity was quantified using an enzyme activity assay kit. The expression levels of collagen I (Col I) and osteopontin (OPN), and core binding factor 1 (Cbfα-1) were detected by reverse transcription polymerase chain reaction and Western blot analysis. The effect of MGF-E on mineralization was determined by Alizarin Red staining and calcium concentration analysis. The kinase inhibitor PD98059 was used to investigate Erk pathway involvement in the MGF-E role.
  
  
  RESULTS
  In the MGF-E-treated osteoblasts, ALP activity decreased with increased Erk activation. The transcription and translation of Col I were inhibited, but those of OPN were enhanced. PD98059 abolished the inhibitory effect and increased the expression of Col I, but decreased that of OPN. Treatment with MGF-E alone up-regulated the mRNA and total protein levels of Cbfα-1, but decreased the fraction of activated Cbfα-1 in the nucleus. Mineralization was delayed by MGF-E, as shown by the bone nodule staining and calcium concentration analysis. These delayed actions were weakened after treatment with PD98059.
  
  
  CONCLUSIONS
  MGF-E could inhibit osteoblast differentiation and mineralization. The possible mechanisms are increased Erk activity and decreased Cbfα-1 nuclear translocation.
authors.affiliation: Bioengineering College, Chongqing University, Chongqing 400030, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Xin
authors.forename: Zhang
authors.initials: Z
authors.lastname: Bingbing
authors.forename: Wang
authors.initials: W
authors.lastname: Yuanliang
authors.forename: Xian
authors.initials: X
authors.lastname: Chengyu
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Deng
authors.initials: D
authors.lastname: Moyuan
authors.forename: Peng
authors.initials: P
authors.lastname: Qin
authors.forename: Li
authors.initials: L
authors.lastname: Yuxiao
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000704:Analysis of Variance; D000880:Anthraquinones; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D003094:Collagen / Q000378:metabolism; D050657:Core Binding Factor alpha Subunits / Q000378:metabolism; D004789:Enzyme Activation; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D020935:MAP Kinase Signaling System; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism*; D053495:Osteopontin / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
chemical_list: D000880:Anthraquinones; D050657:Core Binding Factor alpha Subunits; C406688:core binding factor alpha; C523997:mechano-growth factor E, human; D053495:Osteopontin; C010078:alizarin; D012313:RNA; D007334:Insulin-Like Growth Factor I; D003094:Collagen; D000469:Alkaline Phosphatase; D002118:Calcium