title: Nerve growth factor induces cord formation of mesenchymal stem cell by promoting proliferation and activating the PI3K/Akt signaling pathway.
abstract: OBJECTIVE
  To investigate whether nerve growth factor (NGF) induced angiogenesis of bone marrow mesenchymal stem cells (MSCs) and the underlying mechanisms.
  
  
  METHODS
  Bone marrow MSCs were isolated from femors or tibias of Sprague-Dawley rat, and cultured. The cells were purified after 3 to 5 passages, seeded on Matrigel-coated 24-well plates and treated with NGF. Tube formation was observed 24 h later. Tropomyosin-related kinase A (TrkA) and p75NTR gene expression was examined using PCR analysis and flow cytometry. Growth curves were determined via cell counting. Expression of VEGF and pAkt/Akt were analyzed with Western blot.
  
  
  RESULTS
  NGF (25, 50, 100 and 200 μg/L) promoted tube formation of MSCs. The tubular length reached the maximum of a 2.24-fold increase, when the cells were treated with NGF (50 μg/L). NGF (50 μg/L) significantly enhanced Akt phosphorylation. Pretreatment with the specific PI3K inhibitor LY294002 (10 μmol/L) blocked NGF-stimulated Akt phosphorylation, tube formation and angiogenesis. NGF (25-200 μg/L) did not affect the expression of TrkA and vascular endothelial growth factor (VEGF), but significantly suppressed the expression of p75NTR. NGF (50 μg/L) markedly increased the proliferation of MSCs.
  
  
  CONCLUSIONS
  NGF promoted proliferation of MSCs and activated the PI3K/Akt signaling pathway, which may be responsible for NGF induction of MSC angiogenesis.
authors.affiliation: Cardiovascular Key Lab of Zhejiang Province, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Wen-xia
authors.initials: WX
authors.lastname: Wang
authors.forename: Xin-yang
authors.initials: XY
authors.lastname: Hu
authors.forename: Xiao-jie
authors.initials: XJ
authors.lastname: Xie
authors.forename: Xian-bao
authors.initials: XB
authors.lastname: Liu
authors.forename: Rong-rong
authors.initials: RR
authors.lastname: Wu
authors.forename: Ya-ping
authors.initials: YP
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Jian-an
authors.initials: JA
authors.lastname: Wang
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D002478:Cells, Cultured; D004789:Enzyme Activation; D005434:Flow Cytometry; D008297:Male; D059630:Mesenchymal Stem Cells / Q000187:drug effects*; D020932:Nerve Growth Factor / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction
chemical_list: D020932:Nerve Growth Factor; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt