Biotin-streptavidin cross-bridging: a novel and feasible approach for targeting transplanted cells to damaged tissue

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. Purpose: 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.