1. Academic Validation
  2. Pyrimidine Triazole Thioether Derivatives as Toll-Like Receptor 5 (TLR5)/Flagellin Complex Inhibitors

Pyrimidine Triazole Thioether Derivatives as Toll-Like Receptor 5 (TLR5)/Flagellin Complex Inhibitors

  • ChemMedChem. 2016 Apr 19;11(8):822-6. doi: 10.1002/cmdc.201500471.
Lei Yan 1 Jiaqi Liang 1 Chengbo Yao 1 Peiyao Wu 1 Xianfeng Zeng 1 Kui Cheng 1 Hang Yin 2
Affiliations

Affiliations

  • 1 Center of Basic Molecular Science, Department of Chemistry, Tsinghua University, Beijing, 100082, China.
  • 2 Center of Basic Molecular Science, Department of Chemistry, Tsinghua University, Beijing, 100082, China. yin_hang@tsinghua.edu.cn.
Abstract

Protein-protein interactions have been regarded as "undruggable" despite their importance in many biological processes. The complex formed between host Toll-like Receptor 5 (TLR5) and flagellin, a globular protein that is the main component of a Bacterial flagellum, plays a vital role in a number of pathogen defenses, immunological diseases and cancers. Through high-throughput screening, we identified two hits with a common pharmacophore, which were used to successfully develop a series of small-molecule probes as novel inhibitors of flagellin binding to TLR5. In a multitude of assays, 4-((4-benzyl-5-(pyridin4yl)-4H-1,2,4-triazol-3-yl)thio)pyrido[3',2':4,5]thieno[3,2-d]pyrimidine (TH1020) was identified as a potent antagonist of TLR5 signaling with promising activity (IC50 =0.85±0.12 μm) and specificity. Furthermore, TH1020 was shown to repress the expression of downstream TNF-α signaling pathways mediated by the TLR5/flagellin complex formation. Based on molecular docking simulation, TH1020 is suggested to compete with flagellin and disrupt its association with TLR5. TH1020 provides a much-needed molecular probe for studying this important protein-protein interaction and a lead compound for identifying novel therapeutics targeting TLR5.

Keywords

flagellin; immunomodulators; inhibitors; protein-protein interactions; toll-like receptor 5 (TLR5).

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