Impact of VX-765 and VX-740 on chondrogenesis and inflammatory cytokine release in murine micromass cultures.

Aim: Caspase-1 inhibition is a promising option for degenerative joint diseases such as osteoarthritis; however, there is still a long way to go toward clinical use. One of the open challenges is associated with the non-inflammatory role of this caspase in the inflammatory environment as well as under physiological conditions. This study therefore focuses on two already pre-clinically tested caspase-1 inhibitors, VX-765 and VX-740, to specify their effects on chondrogenic cells.

Material and methods: The analysis was performed on mouse micromass cultures where chondrocyte differentiation, inflammatory cytokine release, and gene expression were examined.

Results: Our data indicate that the inhibitor VX-740 increases chondrogenesis, suggesting osteocalcin as a target molecule. In the inflammatory environment induced by IL-1β, there was an increase in chondrogenic nodules and partial compensation of differentiation for both investigated inhibitors. Morphological changes were not primarily due to changes in chondrogenic/osteogenic gene expression, but different levels of inflammatory molecules were found in the culture supernatant. While an increase in anti-inflammatory cytokine levels was observed with VX-765, a decrease in pro-inflammatory cytokines was recorded in the case of VX-740 treatment.

Conclusion: The results demonstrate the differential effects of the caspase-1 inhibitors VX-765 and VX-740 on chondrogenic cell cultures and point to molecules that may be potential targets for use in the local treatment of osteoarthritis.