Differential roles of TGF-β signalling in joint tissues during osteoarthritis development

Osteoarthritis (OA) is the most common degenerative joint disease. The aetiology of OA is multifactorial, including joint injury, obesity, ageing and heredity. Inactivation of transforming growth factor beta (TGF-β) or its downstream molecules may be an important signalling event contributing to OA pathogenesis because mutations of Smad3 , a central molecule in TGF-β signalling, have been found in patients with early-onset OA.1–3 It has been known for many years that TGF-β promotes matrix protein …