title: Biotin-streptavidin cross-bridging: a novel and feasible approach for targeting transplanted cells to damaged tissue.
abstract: BACKGROUND
  Accumulating evidence indicates the positive impact of endothelium-derived cell therapy in vascular repair. However, low cell transplantation efficiency inevitably and greatly reduces the treatment efficacy of cell transplants.
  
  
  OBJECTIVE
  To modify the surfaces of cells with polypeptides or small-molecule proteins that specifically recognize and bind to damaged tissue.
  
  
  METHODS
  We used a biotin-streptavidin binding approach to attach annexin V, which recognizes apoptotic cells, onto bEnd.3 cells that express vascular endothelial growth factor receptor 2 (VEGFR2) and verified that the modified cells could efficiently bind to dead cells in vitro.
  
  
  RESULTS
  We analyzed biotinylated VEGFR2-bEnd.3 cells, streptavidin-biotinylated VEGFR2-bEnd.3 cells, and biotinylated annexin V-streptavidin-biotinylated VEGFR2-bEnd.3 cells. Our results from flow cytometry analysis and immunofluorescent examination demonstrated that we successfully labeled the cells in a three-step process. Furthermore, we determined that the positive binding rate correlated with reagent concentration. Immunofluorescent examination illustrated that adding the biotinylated annexin V-streptavidin-biotinylated VEGFR2-bEnd.3 cells to dead cells led to the clustering and aggregation of the modified cells and the dead cells.
  
  
  CONCLUSIONS
  Annexin V can be attached to bEnd.3 cells using a biotin-streptavidin binding approach, and the modified cells can specifically recognize and bind to dead cells.
authors.affiliation: Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China.
authors.forename: Mao
authors.initials: M
authors.lastname: Chen
authors.forename: Jia-Fu
authors.initials: JF
authors.lastname: Wei
authors.forename: Yuan-Ning
authors.initials: YN
authors.lastname: Xu
authors.forename: Yong
authors.initials: Y
authors.lastname: Peng
authors.forename: Hua
authors.initials: H
authors.lastname: Chai
authors.forename: Qiao
authors.initials: Q
authors.lastname: Li
authors.forename: Xiao-Jing
authors.initials: XJ
authors.lastname: Liu
authors.forename: De-Jia
authors.initials: DJ
authors.lastname: Huang
mesh_terms: D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D001710:Biotin / Q000737:chemistry*; D017690:Cell Transplantation; D005240:Feasibility Studies; D005455:Fluorescent Antibody Technique; D051379:Mice; D019809:Streptavidin / Q000737:chemistry* / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000737:chemistry / Q000378:metabolism
chemical_list: D017304:Annexin A5; D001710:Biotin; D019809:Streptavidin; D040301:Vascular Endothelial Growth Factor Receptor-2