T5224 is known as an AP‐1 inhibitor.[42] We compared chondrocytes treated with Ad‐activin A or Ad‐Nox4 infection with or without 20 × 10−6m of T5224, and those treated with Ad‐C infection versus Ad‐activin A or Ad‐Nox4 infection with or without 20 × 10−6m of T5224. Here, FOS is linked to infection.