Role of lineage-specific matrix in stem cell chondrogenesis

Cartilage repair in clinics is a challenge owing to the limited regenerative capacities of cartilage. Synovium-derived stem cells (SDSCs) are suggested as tissue-specific stem cells for chondrogenesis. In this study, we hypothesize that decellularized extracellular matrix (dECM) deposited by SDSCs could provide a superior tissue-specific matrix microenvironment for optimal rejuvenation of adult SDSCs for cartilage regeneration. dECMs were deposited by adult stem cells with varying chondrogenic capacities; SDSCs (strong) (SECM), adipose-derived stem cells (weak) (AECM) and dermal fibroblasts (weak) (DECM), and urine-derived stem cells (none) (UECM). Plastic flasks (Plastic) were used as a control substrate. Human SDSCs were expanded on the above substrates for one passage and examined for chondrogenic capacities. We found that each dECM consisted of unique matrix proteins and exhibited varied stiffnesses, which affected cell morphology and elasticity. Human SDSCs grown on dECMs displayed a significant increase in cell proliferation and unique surface phenotypes. Under induction media, dECM expanded cells yielded pellets with a dramatically increased number of chondrogenic markers. Interestingly, SECM expanded cells had less potential for hypertrophy compared to those grown on other dECMs, indicating that a tissue-specific matrix might provide a superior microenvironment for stem cell chondrogenic differentiation.