TNF and inflammatory response: In the study revealing the miR-18a-3p/HOXA1 axis in OA [21], HOAX1 inhibits chondrocyte apoptosis and act as a protective role in OA progression; in the study revealing the enhancer role of miR-18a-5p in TNFα-induced cartilage destruction and chronic inflammation [31], NF-κB is an inducer of miR-18a-5p and NF-κB activation is known to be involved in many chronic inflammatory diseases [32].