Delineation of in vitro chondrogenesis of human synovial stem cells following preconditioning with decellularized matrix

As a tissue-specific stem cell for chondrogenesis, synovium-derived stem cells (SDSCs) are a promising cell source for cartilage repair. However, a small biopsy can only provide a limited number of cells. Cell senescence from both in vitro expansion and donor age presents a big challenge for stem cell based cartilage regeneration. Here we found that expansion on decellularized extracellular matrix (dECM) full of three-dimensional nanostructured fibers provided SDSCs with unique surface profiles, low elasticity but large volume as well as fibroblast-like shape. dECM expanded SDSCs yielded large pellets with intensive staining of type II collagen and sulfated GAGs, which was supported by both biochemical data and real-time PCR results. Our results also hint at lower levels of inflammatory genes and how they might be responsible for enhanced chondrogenic differentiation in dECM expanded SDSCs. Despite an increase of type X collagen in chondrogenically induced cells, dECM expanded cells had significantly lower potential for endochondral bone formation. Both Wnt and MAPK signals were actively involved in both expansion and chondrogenic induction of dECM expanded cells. dECM expanded human SDSCs could be a potential cell source for autologous cartilage repair Adult human synovial fibroblasts (4 donors, two male and two female, average 43 years old, all had no known joint disease) were grown for one passage on plastic flasks (P cells) or plastic flasks pre-coated with decellularized extracellular matrix (E cells). Aliquots were centrifuged and pellets cultured for 35 days in serum-free chondrogenic medium (P pellet or E pellet). There are no replicates.