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. Author manuscript; available in PMC: 2009 Oct 3.
Published in final edited form as: Science. 2009 Apr 3;324(5923):59–63. doi: 10.1126/science.1169494

Figure 4. Influence of dynamic microenvironment chemistry on integrin expression and differentiation.

Figure 4

(A) Cells (DAPI-labeled nuclei, blue) cultured with persistent RGDS express the cell-surface integrin αvβ3 (FITC-labeled, green) on at Day 4 (left) and Day 21 (middle) in culture. Cells with photocleaved RGDS have decreased expression of the αvβ3 integrin by Day 21 (right), indicating that the cells have responded to the removal of RGDS. (Representative images shown with average cell percentages noted.) (B) Chondrogenic differentiation of hMSCs was verified by immunostaining for the hMSC marker CD105 (FITC, green) and the chondrocyte marker COLII (TRITC, red). Within error, no cells initially produce COLII (Day 4, left). By Day 21, half of the cells presented persistently with RGDS strongly expressed CD105 and the other half produced COLII (middle). With photolytic removal of RGDS on Day 10, one-fourth of the cells strongly expressed CD105 and three-fourths produced COLII (right), supporting that photolytic removal of RGDS increases chondrogenesis. (Representative images shown with average cell percentages strongly expressing the marker noted.) Scale bars, 100 μm.