Shen Pingping, Jiang Xuewa, Kuang Yi, Wang Weiwei, Raj Richa, Wang Wei, Zhu Yuyuan, Zhang Xiaochun, Yu Boyang, Zhang Jian
Department of Resources Science of Traditional Chinese Medicines, School of Traditional Chinese Pharmacy, China Pharmaceutical University Nanjing 210009 P. R. China
Nanjing Hospital of Chinese Medicine Affiliated to Nanjing University of Chinese Medicine Nanjing 210046 P. R. China.
RSC Chem Biol. 2024 Jun 7;5(8):751-762. doi: 10.1039/d4cb00062e. eCollection 2024 Jul 31.
HMGB1 interacts with TLR4 to activate the inflammatory cascade response, contributing to the pathogenesis of endogenous tissue damage and infection. The immense importance of HMGB1-TLR4 interaction in the immune system has made its binding interface an area of significant interest. To map the binding interface of HMGB1 occupied by TLR4, triterpenoids that disrupt the HMGB1-TLR4 interaction and interfere with HMGB1-induced inflammation were developed. Using the unique triterpenoid PT-22 as a probe along with photoaffinity labeling and site-directed mutagenesis, we found that the binding interface of HMGB1 was responsible for the recognition of TLR4 located on the "L" shaped B-box with K114 as a crucial hot-spot residue. Amazingly, this highly conserved interaction surface overlapped with the antigen-recognition epitope of an anti-HMGB1 antibody. Our findings propose a novel strategy for better understanding the druggable interface of HMGB1 that interacts with TLR4 and provide insights for the rational design of HMGB1-TLR4 PPI inhibitors to fine tune immune responses.
高迁移率族蛋白B1（HMGB1）与Toll样受体4（TLR4）相互作用，激活炎症级联反应，促进内源性组织损伤和感染的发病机制。HMGB1与TLR4相互作用在免疫系统中的极其重要性，使其结合界面成为一个备受关注的领域。为了绘制TLR4占据的HMGB1结合界面，开发了破坏HMGB1与TLR4相互作用并干扰HMGB1诱导炎症的三萜类化合物。使用独特的三萜类化合物PT-22作为探针，结合光亲和标记和定点诱变，我们发现HMGB1的结合界面负责识别位于“L”形B盒上的TLR4，其中K114是关键的热点残基。令人惊讶的是，这个高度保守的相互作用表面与抗HMGB1抗体的抗原识别表位重叠。我们的研究结果提出了一种新策略，以更好地理解与TLR4相互作用的HMGB1的可药物作用界面，并为合理设计HMGB1-TLR4蛋白-蛋白相互作用抑制剂以微调免疫反应提供见解。
