A novel tylophorine analog NK-007 ameliorates colitis through inhibition of innate immune response.

Abstract In this study, we synthesized (±)-tylophorine malate (NK-007), an analog of tylophorine (DCB3503), and analyzed its anti-inflammatory effect in vivo using a dextran sulfate sodium (DSS)-induced colitis model and an acetic acid-induced colitis model. As indicated by disease activity index (DAI) and degree of macroscopic colonic damage, NK-007 can significantly suppress colitis. To delineate the underlying mechanism, we have explored the influence of NK-007 on the production of TNF-α by murine primary bone marrow-derived dendritic cells (BMDCs) as well as monocyte/macrophage cell line Raw 264.7 triggered by lipopolysaccharide (LPS). For both types of innate immune cells, NK-007 showed a potent TNF-α inhibitory effect, and has in addition reduced the expression of IL-12 in BMDCs. Moreover, Raw cells treated with NK-007 also showed decreased phosphorylation of NF-κB, which may explain the protective immune-regulatory effect of NK-007 for experimental colitis.