Enhanced Growth of Bone Marrow-Derived Mesenchymal Stem Cells on the Microcarriers Tethered With Engineered Basic Fibroblast Growth Factor

Microcarrier-based bioreactors have been studied extensively for the expansion of human mesenchymal stem cells (hMSCs) to be used in regenerative therapy. To maximize the expansion efficiency, we developed microcarriers that tethered basic fibroblast growth factor (bFGF) on their surfaces. Using recombinant DNA technologies, bFGF was fused with a collagen-binding peptide (CBP) and bound to microcarriers that had been coated with type I collagen. In this study, we examined two types of CBP: a 28-mer peptide derived from human osteopontin (CBP1) and an 11-mer peptide derived from human decorin (CBP2). The chimeric proteins, CBP1-bFGF and CBP2-bFGF, were prepared using a bacterial expression system. Their structures were analyzed by circular dichroism spectroscopy and computer-based structure prediction, and their biological functions were assessed in hMSC cultures. Based on the results of these experiments, refolding conditions were optimized to increase the yields of soluble and bioactive CBP1-bFGF and CBP2-bFGF. Microcarriers that were tethered with CBP1-bFGF and CBP2-bFGF promoted hMSC growth without considerably altering their surface marker expression and osteogenic differentiation ability. These findings highlighted the potential of bFGF-tethered microcarriers as essential bioreactor components for hMSC expansion.