3D matrix adhesions mediating mechanostranduction in hMSC-collagen constructs

The current study aims to identify the type of cell-matrix adhesions of hMSCs in 3D collagen constructs and to investigate the effects of dynamic compression on the type, morphology and composition of cell-matrix adhesions, particularly to observe whether the compression stimulates the maturation or evolvement of 3D matrix adhesion in hMSC-collagen constructs. Preliminary results demonstrated the colocalization of integrin α₅β₁ and fibronectin in cell-matrix adhesions in loaded constructs, partially fulfilling the requirements for 3D matrix adhesion to evolve. In addition, fibronectin was shown to be organized into tiny-dotted adhesions in loaded constructs in a loading duration dependent way, suggesting dynamic compression may be able to mature adhesions in the constructs, hopefully into 3D matrix adhesions. It was also demonstrated that hMSCs plated onto their own cell-derived matrices form elongated adhesions which are similar to 3D matrix adhesions formed by fibroblasts. Further characterization on the cell-matrix adhesions of hMSCs in 3D collagen constructs and identification of differences in adhesions between loaded and unloaded constructs are underway.