Abstract: Ｏｂｊｅｃｔｉｖｅ：This study aimed to construct a highthroughput screening system to screen from natural product libraries targeting Tolllike receptor 7 (TLR7), an important target of lupus nephritis (LN).
Ｍｅｔｈｏｄｏｌｏｇｙ：The screening system was constructed based on the HEKBlueTM hTLR7 cell line stably expressing hTLR7 and SEAP genes, the optimal working concentrations of TLR7 ligand resiquimod (R848) and positive drug hydroxychloroquine (HCQ) were optimized. And active natural product libraries were screened for TLR7 inhibitors in the primary and secondary screening.
Ｒｅｓｕｌｔｓ：Our results showed that cucurbitacin B (CuB) could significantly inhibit TLR7 activity with little effect on cell viability. Then the spleen mononuclear cells of MRL／lpr lupus mice were isolated and cultured in vitro and treated with CuB. The expressions of TLR7 downstream signaling molecules and inflammatory factors were detected by western blot and qPCR. In vitro experiments confirmed that CuB can inhibit the expression of TLR7 downstream signaling molecules MyD88 and pp65, the secretion of inflammatory factors interleukin 6 (IL6)、interferon γ (IFNγ) and the expression of type I interferon signature genes (ISGs).
Ｃｏｎｃｌｕｓｉｏｎ：In summary, this study successfully established a highthroughput screening model with TLR7 as the target and a new TLR7 inhibitor CuB was screened, which provided a lead compound for the treatment of LN.