P15 peptide stimulates chondrogenic commitment and endochondral ossification.

Purpose: The synthetic 15 amino acid biomimetic peptide sequence (P15) derived from a region of the alpha (α)-1 chain of collagen I, has been shown to promote α2 integrin activation and enhance intramembranous ossification. In this study, we ask if the P15 peptide also enhances bone formation through endochondral ossification, and determine if direct binding of α2 integrin with P15 mediates integrin activation.

Methods: Mesenchymal cells (C3H10T1/2) were cultured in chondrogenic media and the expression of chondrogenic markers and integrin activation was determined by Western blot and fluorescent immunohistochemistry.

Stress-Induced Activation of Apoptosis Signal-Regulating Kinase 1 Promotes Osteoarthritis.

Apoptosis signal-regulated kinase 1 (ASK1) has been shown to affect a wide range of cellular processes including stress-related responses, cytokine and growth factor signaling, cell cycle and cell death. Recently, we reported that lack of ASK1 slowed chondrocyte hypertrophy, terminal differentiation and apoptosis resulting in an increase in trabecular bone formation. Herein, we investigated the role of ASK1 in the pathogenesis of osteoarthritis (OA).