title: Effects of bone marrow-derived mesenchymal stem cells on the axonal outgrowth through activation of PI3K/AKT signaling in primary cortical neurons followed oxygen-glucose deprivation injury.
abstract: BACKGROUND
  Transplantation with bone marrow-derived mesenchymal stem cells (BMSCs) improves the survival of neurons and axonal outgrowth after stroke remains undetermined. Here, we investigated whether PI3K/AKT signaling pathway is involved in these therapeutic effects of BMSCs.
  
  
  RESULTS
  (1) BMSCs and cortical neurons were derived from Sprague-Dawley rats. The injured neurons were induced by Oxygen-Glucose Deprivation (OGD), and then were respectively co-cultured for 48 hours with BMSCs at different densities (5×10(3), 5×10(5)/ml) in transwell co-culture system. The average length of axon and expression of GAP-43 were examined to assess the effect of BMSCs on axonal outgrowth after the damage of neurons induced by OGD. (2) The injured neurons were cultured with a conditioned medium (CM) of BMSCs cultured for 24 hours in neurobasal medium. During the process, we further identified whether PI3K/AKT signaling pathway is involved through the adjunction of LY294002 (a specific phosphatidylinositide-3-kinase (PI3K) inhibitor). Two hours later, the expression of pAKT (phosphorylated AKT) and AKT were analyzed by Western blotting. The length of axons, the expression of GAP-43 and the survival of neurons were measured at 48 hours.
  
  
  RESULTS
  Both BMSCs and CM from BMSCs inreased the axonal length and GAP-43 expression in OGD-injured cortical neurons. There was no difference between the effects of BMSCs of 5×10(5)/ml and of 5×10(3)/ml on axonal outgrowth. Expression of pAKT enhanced significantly at 2 hours and the neuron survival increased at 48 hours after the injured neurons cultured with the CM, respectively. These effects of CM were prevented by inhibitor LY294002.
  
  
  CONCLUSIONS
  BMSCs promote axonal outgrowth and the survival of neurons against the damage from OGD in vitro by the paracrine effects through PI3K/AKT signaling pathway.
authors.affiliation: Department of Neurology, Fujian Medical University Union Hospital, Fuzhou, Fujian, People Republic of China ; Institute of Cerebral Vascular Disease of Fujian Province, Fuzhou, Fujian, People Republic of China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Liu
authors.forename: Yixian
authors.initials: Y
authors.lastname: Zhang
authors.forename: Longzai
authors.initials: L
authors.lastname: Lin
authors.forename: Feifei
authors.initials: F
authors.lastname: Lin
authors.forename: Tin
authors.initials: T
authors.lastname: Li
authors.forename: Houwei
authors.initials: H
authors.lastname: Du
authors.forename: Ronghua
authors.initials: R
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.forename: Nan
authors.initials: N
authors.lastname: Liu
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism*; D001854:Bone Marrow Cells / Q000166:cytology*; D001921:Brain / Q000166:cytology*; D002470:Cell Survival; D005260:Female; D019922:GAP-43 Protein / Q000378:metabolism; D005786:Gene Expression Regulation; D005947:Glucose / Q000172:deficiency*; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000166:cytology; D010100:Oxygen / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D011247:Pregnancy; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction
chemical_list: D019922:GAP-43 Protein; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D005947:Glucose; D010100:Oxygen