Discoidin domain receptor 2: An emerging pharmacological drug target for prospective therapy against osteoarthritis.

Discoidin domain receptor2 (DDR2), a cell membrane tyrosine kinase on chondrocytes surface plays main role in cell-ECM interaction during the progressive degeneration of articular cartilage in osteoarthritis. The degraded component of ECM, type II collagen upon DDR2 binding provokes synthesis of matrix metalloproteinases (MMPs), responsible for severe destruction of joint tissues. DDR2 knockout has been investigated to decline the expression of MMP-1 and 13. Previously, various molecules were effective in preclinical level against different targets in OA, but found to be collapsed in clinical trial due to insufficient target specificity and clinical toxicity. Review emphasizes the role of DDR2 in the degeneration of cartilage in osteoarthritis (OA) and its blocking by DDR2 antagonist attenuates the disease severity. DDR2 in chondrocytes contributes paramount role in degradation of cartilage at early stage of osteoarthritis via collagen 2 binding through the felicitation of TGF-β signaling molecule and other triggering factors. DDR2 involvement in regulation of matrix metalloproteinase (MMP), cross talking interaction in maintenance of ECM-chondrocytes, bone developments, interference RNA and designing the DDR2 antagonists have been critically investigated. The exploration may conclude that the DDR2 could be the novel pharmacological target to prevent the progression of osteoarthritis at early stage because of over expression of DDR2 and MMP which further promotes severe cartilage degeneration. Owing to pharmacological specificity of DDR2 in OA as drug target, it is to be hypothesized that development of safe molecules as DDR2 antagonist could be the good option in the treatment of OA with promising landmark.