TGFB1 and osteoarthritis: miR-146 has previously been identified to modulate myofibroblast trans-differentiation during TGF-β1 induction by targeting SMAD4 [18], [36] and miR-146 may also be an important regulator during the inflammatory state of osteoarthritis, as IL-1β induced production of TNF-α, a pro-inflammatory cytokine known to play a role in osteoarthritis, was significantly reduced by miR-146 overexpression [19], [20], [37].