Fig. 2. Negative-regulation of the late stage of endochondral ossification by Sex-determining region Y (SRY)-box 9 (Sox9) and Indian hedgehog (Ihh)/parathyroid hormone-related protein (PTHrP) loop. Sox9 and Ihh/Gli2 signaling cooperatively inhibit chondrocyte hypertrophy through upregulation of PTHrP, in which forkhead box C1 (Foxc1) is also involved. On the hand, Sox9 suppresses vascular invasion into cartilage by inhibiting vascular endothelial growth factor (VEGF) expression.
