MS80, a novel sulfated polysaccharide, inhibits CD40-NF-κB pathway via targeting RIP2

In the previous studies, MS80 was found to be able to inhibit the pulmonary fibrosis. However, the target of MS80 remains unclear. To determine the target and the anti-fibrosis mechanisms of MS80, affinity column, MALDI-TOF-MS/MS, co-immunoprecipitation, and co-localization were used. The results showed that MS80 targeting protein was receptor interacting protein 2 (RIP2), which was further confirmed by co-immunoprecipitation and co-localization. Moreover, MS80 inhibited the CD40 ligation-induced NF-κB activation, and subsequently inflammatory cytokines secretion, the collagen synthesis, and the excessive proliferation of fibroblasts. Thus the detailed molecular machinery was ascribed to the involvement of MS80 in targeting CD40 signal pathway via binding and blocking RIP2, the key component of CD40 signal transduction. The findings addressed here may substantially account for the effects of MS80 in combating the pulmonary fibrosis.