Toll‐like receptor 2 antagonists identified through virtual screening and experimental validation

Toll‐like receptor 2 ( TLR 2) antagonists are key therapeutic targets because they inhibit several inflammatory diseases caused by surplus TLR 2 activation. In this study, we identified two novel nonpeptide TLR 2 antagonists, C11 and C13, through pharmacophore‐based virtual screening. At 10 μ m , the level of interleukin (IL)‐8 inhibition by C13 and C11 in human embryonic kidney TLR 2 overexpressing cells was comparable to the commercially available TLR 2 inhibitor CU ‐ CPT 22. In addition, C11 and C13 acted in mouse macrophage‐like RAW 264.7 cells as TLR 2‐specific inhibitors and did not suppress the tumor necrosis factor‐α induction by TLR 3 and TLR 4 activators. Moreover, the two identified compounds bound directly to the human recombinant TLR 2 ectodomain, during surface plasmon resonance analysis, and did not affect cell viability in a 3‐(4,5‐dimethylthiazol‐2‐yl)‐5(3‐carboxymethonyphenol)‐2‐(4‐sulfophenyl)‐2 H ‐tetrazolium assay. In total, two virtually screened molecules, C11 and C13, were experimentally proven to be effective as TLR 2 antagonists, and thus will provide new insights into the structure of TLR 2 antagonists, and pave the way for the development of TLR 2‐targeted drug molecules.