EXTRACELLULAR MATRIX FROM HIPSC-MESENCHYMAL PROGENITORS MODULATES THE THREE-LINEAGE DIFFERENTIATION OF HUMAN BONE MARROW STROMAL CELLS

Mesenchymal stromal cells from the bone marrow (BMSCs) exhibit a functional decline during aging. We previously found that extracellular matrix (ECM) engineered from human induced pluripotent stem cell-derived mesenchymal progenitors enhances the osteogenic capacity of BMSCs. In the current study, we investigated how this ECM affects the three-lineage differentiation and secretory activity of BMSCs. BMSCs were seeded on the ECM layer and osteogenic, adipogenic and chondrogenic lineages were induced in monolayer or micromass cultures. Differentiation responses were compared to controls on tissue culture plastic after 21 days, and secretion of interleukin 6 was evaluated after 3 and 21 days of culture. We found a significant increase in BMSC growth on the ECM in all three differentiation media compared with controls. Osteogenic cultures on the ECM resulted in significantly higher alkaline phosphatase activity, osteogenic gene expression, collagen deposition, and matrix mineralization. In adipogenic cultures, a significant decline in adipocyte formation was found on the ECM. Chondrogenic induction on the ECM resulted in significantly increased chondrogenic gene expression, glycosaminoglycans deposition and collagen type II deposition, and no significant increase in collagen type X gene expression compared to control. Secretion of interleukin 6 was modulated by the three differentiation media and culture surface, and was reduced after 21 days of osteogenic and chondrogenic induction on the ECM. Together, our data suggest that engineered ECM modulates BMSCs trilineage differentiation toward enhanced osteogenesis and chondrogenesis, and reduced adipogenesis. Thus, our ECM might provide a bioactive component for enhancing osteochondral regeneration in older patients.