title: EphB4 Promotes Osteogenesis of CTLA4-Modified Bone Marrow-Derived Mesenchymal Stem Cells Through Cross Talk with Wnt Pathway in Xenotransplantation.
abstract: BACKGROUND
  Cytotoxic T lymphocyte-associated antigen 4-Ig (CTLA4-Ig)-modified bone marrow-derived mesenchymal stem cells (MSCs-CTLA4) have excellent osteogenic function in xenografts, but their mechanism of action remains to be elucidated. As bidirectional signaling between erythropoietin-producing hepatocyte receptors B4 (EphB4) and ephrinB2 is vital for bone remodeling, this study aimed to fully characterize the role of MSCs-CTLA4 in promoting bone regeneration in xenotransplantation through EphB4/ephrinB2 and their cross talk with the Wnt/beta-catenin pathway.
  
  
  METHODS
  MSCs-CTLA4 were investigated for their osteogenic capacity through xenotransplantation in vivo. MSCs-CTLA4 were treated with ephrinB2-FC or FC under conditions of osteogenic induction and cultured with or without immune activation conditions established by phytohemagglutinin and peripheral blood mononuclear cells in vitro. Osteogenesis markers and the Wnt pathway-related molecules such as EphB4, runt-related transcription factor 2 (Runx2), collagen 1 (COL1), osteocalcin (OCN), alkaline phosphatase (ALP), calcium nodus, β-catenin, phospho-glycogen synthase kinase 3-beta (p-GSK-3β)-Ser9, and glycogen synthase kinase 3-beta (GSK-3β) were detected.
  
  
  RESULTS
  MSCs-CTLA4-based xenografts show better osteogenic capacity compared with MSC-based xenografts. EphB4 expression was reduced in MSCs compared with MSCs-CTLA4 under immune activation conditions. In ephrinB2-FC-treated cells, levels of osteogenesis markers were increased compared with FC-treated cells. The activity of GSK-3 was inhibited and the expression of β-catenin in MSCs was increased by ephrinB2-FC treatment.
  
  
  CONCLUSIONS
  CTLA4 modification maintains EphB4 expression in MSCs under immune activation conditions, and EphB4 cross talk with the Wnt pathway promotes osteogenic differentiation of MSCs-CTLA4.
authors.affiliation: 1 National & Regional United Engineering Laboratory of Tissue Engineering, Third Military Medical University , Chongqing, People's Republic of China .|2 Department of Orthopaedics, Southwest Hospital, Third Military Medical University , Chongqing, People's Republic of China .
authors.forename: Fei
authors.initials: F
authors.lastname: Zhang
authors.affiliation: 1 National & Regional United Engineering Laboratory of Tissue Engineering, Third Military Medical University , Chongqing, People's Republic of China .|2 Department of Orthopaedics, Southwest Hospital, Third Military Medical University , Chongqing, People's Republic of China .
authors.forename: Zehua
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: 1 National & Regional United Engineering Laboratory of Tissue Engineering, Third Military Medical University , Chongqing, People's Republic of China .|2 Department of Orthopaedics, Southwest Hospital, Third Military Medical University , Chongqing, People's Republic of China .
authors.forename: Dong
authors.initials: D
authors.lastname: Sun
authors.affiliation: 1 National & Regional United Engineering Laboratory of Tissue Engineering, Third Military Medical University , Chongqing, People's Republic of China .|3 Department of Biomedical Materials Science, School of Biomedical Engineering, Third Military Medical University , Chongqing, People's Republic of China .
authors.forename: Shiwu
authors.initials: S
authors.lastname: Dong
authors.affiliation: 1 National & Regional United Engineering Laboratory of Tissue Engineering, Third Military Medical University , Chongqing, People's Republic of China .|2 Department of Orthopaedics, Southwest Hospital, Third Military Medical University , Chongqing, People's Republic of China .
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Xu
authors.affiliation: 1 National & Regional United Engineering Laboratory of Tissue Engineering, Third Military Medical University , Chongqing, People's Republic of China .|2 Department of Orthopaedics, Southwest Hospital, Third Military Medical University , Chongqing, People's Republic of China .
authors.forename: Fei
authors.initials: F
authors.lastname: Dai
mesh_terms: D000328:Adult; D000818:Animals; D001842:Bone and Bones / Q000502:physiology; D060908:CTLA-4 Antigen / Q000378:metabolism*; D002454:Cell Differentiation; D006801:Humans; D008297:Male; D059630:Mesenchymal Stem Cells / Q000378:metabolism*; D008807:Mice, Inbred BALB C; D010012:Osteogenesis; D060888:Real-Time Polymerase Chain Reaction; D036224:Receptor, EphB4 / Q000378:metabolism*; D023822:Tissue Engineering; D014183:Transplantation, Heterologous; D060449:Wnt Signaling Pathway
chemical_list: D060908:CTLA-4 Antigen; D036224:Receptor, EphB4