Genetically modified MSCs into neural and endothelial cell-like cells induced by a branched peptide amphiphile hydrogel

Abstract Background： Spinal cord injury (SCI) remain one of the great clinical challenges because of their considerable long-term disability potential. In this study, A branched amphiphilic peptide (B-PA) segments were constructed and self-assembled into hydrogels to support bone marrow derived mesenchymal stromal cells (BMSCs) encoding Recombinant Rat VEGF165（VEGF165）, neurotrophins-3(NT-3)and angiopoietin-1(ANG-1) genes. In addition, B-PAS promoted the transdifferentiation of BMSCs into nerve and vascular endothelial cells. Methods：Self-assembly of b-PA into a nanofiber hydrogel was triggered by the culture medium and analysed by transmission electron microscopy (TEM). Rat BMSCs were cultivated using the differential adhesion method and assessed by flow cytometry. Cells were inoculated into the hydrogel and investigated using calcein-AM/PI, CCK-8, and cell adhesion assays. Cells transfected with adenoviral vectors of biocarrier (Adv-Bic) and adenoviral vectors of NT-3 gene (AdvNT-3) were cultured for 7 days and evaluated by immunofluorescence and real time quantitative reverse transcription-PCR. Results：The molecular weight and purity of b-PA were 2191.72 and >95%, respectively. Self-assembled nanofibers had a diameter of 5-8 nm and a length ranging from hundreds of nanometres to micrometres. The resulting CD29+/44+ cells could differentiate into osteoblasts and fat cells, and the hydrogel supported cell growth, proliferation and adhesion. Cells in the hydrogel overexpressed VEGF165, NT-3 and Ang-1, and NSE and Nestin markers of CD31+/34+ cells were also abundant. Conclusions： The hydrogel has potential as a tissue engineering scaffold with good cytocompatibility, and can induce genetically modified BMSCs to transdifferentiate into neural and endothelial cell (EC)-like cells.