Emerging strategies in reprogramming and enhancing the fate of mesenchymal stem cells for bone and cartilage tissue engineering.

Mesenchymal stem cells (MSCs) are used extensively in developing tissue engineered constructs for bone and cartilage regeneration. An important factor in designing such constructs is that the MSCs are appropriately primed to differentiate along osteogenic or chondrogenic lineage. In contrast to a top-down method of tissue engineering where the differentiation of cells is guided by the scaffold and signals, a bottom-up method involves direct modulation of stem cell behavior without relying on the environmental cues. In this review, we discuss several bottom-up strategies that have emerged in engineering MSC behavior for bone and cartilage tissue engineering, including gene delivery, gene editing, and subpopulation isolation.