Suspension-based differentiation of adult mesenchymal stem cells toward chondrogenic lineage

Human mesenchymal stem cells (hMSCs) are derived from bone marrow and have the ability to differentiate into cartilage and other mesenchymal cell types found throughout the body. Traditionally, the differentiation of hMSCs toward chondrocytes occurs through a combination of pelleted static cell culture and chemical stimuli. As an alternative to these protocols, we developed an in vitro flow through microfluidic method to induce the differentiation of hMSCs into chondrocytes. Suspensions of unattached hMSCs were exposed to a constant shear flow over a period of 20 minutes, which promoted phenotypic and gene expression changes toward the chondrogenic lineage. These internal and external changes of chondrogenic differentiation were then observed over 3 weeks later in culture, as confirmed through fluorescent immunocytochemical staining and real-time quantitative reverse transcriptase polymerase chain reaction. The increased concentration of Type II collagen on the surface of shear stimulated hMSCs with the upregulation of MAPK1 and SOX9 demonstrated the capabilities of our approach to induce sustained differentiation. In conclusion, our shear stimulation method, in combination with chemical stimuli, illustrates enhanced differentiation of hMSCs toward the chondrogenic lineage.