AbstractOne of the major challenges within the rapidly growing field of regenerative medicine is the efficient integration of stem cells after transplantation. To address this issue, an artificial cell membrane binding nanobiohybrid was rationally designed to provide donor cells with cartilage tissue adhesion properties. The protein constituent consists of a peptide sequence from placenta growth factor 2 (PlGF-2) fused to a supercharged green fluorescent protein (scGFP), giving [scGFP_PlGF2]. Significantly, PlGF-2 has an extremely high binding affinity for extracellular matrix (ECM) proteins and the supercationic scGFP provides a cell membrane anchor region for anionic polymer surfactant conjugation. Accordingly, the solvent-exposed sites of the protein were electrostatically conjugated with a polymer surfactant, forming [scGFP_PlGF2][S]. This allowed the construct to insert into the membrane of human mesenchymal stems cells (hMSCs), whilst the PlGF2 domain is displayed to provide the cells with affinity for ECM proteins.
The addition of the polymer surfactant did not affect the structure and function of the fusion protein. Moreover, hMSCs modified with [scGFP_PlGF2][S] did not exhibit any signs of cytotoxicity at working concentrations, and there was no impact on the cells ability to proliferate or differentiate. Importantly, there was a significant increase in cellular adherence to collagen II when comparing modified cells to unmodified cells with in vitro models. Moreover, the modified cells adhered strongly to bovine ex vivo articular cartilage explants and could be readily observed on the cartilage using confocal and electron microscopy. These findings suggest that re-engineering hMSC membranes with [scGFP_PlGF2] could be a viable approach to improve stem cell therapy outcomes in the regeneration of damaged cartilage tissue.
|Date of Award||25 Jun 2019|
|Supervisor||Wael Kafienah (Supervisor) & Adam W Perriman (Supervisor)|