Figure 7.

Model of age‐dependent tenocyte phenotype determination via hypoxic Rac1 inhibition. Microenvironmental cues including oxygen and cell density determine the human tenocyte phenotype. Hypoxia and low cell density in young tenocytes (a) activate Rac1 which inhibits RhoA, driving the tenocyte phenotype and repressing fibrochondrocyte and mineralized fibrochondrocyte formation. In aged tenocytes (b), hypoxia and low cell density inhibit Rac1 activity, allowing RhoA activation and formation of the fibrochondrocyte and mineralized fibrochondrocyte phenotype