State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin, 300353, China.
Tianjin University of Traditional Chinese Medicine, Tianjin, 300193, China.
Phytomedicine. 2024 Dec;135:156171. doi: 10.1016/j.phymed.2024.156171. Epub 2024 Oct 21.
Inflammation plays a significant role in initiating and sustaining rheumatoid arthritis (RA). Acacetin, a natural flavonoid compound, exhibits excellent anti-inflammatory effects specifically for RA. However, its relevant targets and molecular mechanisms remain to be elucidated.
This study aims to investigate the mechanism of acacetin in the therapeutic efficacy of acacetin in RA and search for new therapeutic options for RA treatment.
A collagen-induced RA mouse model was established to evaluate the therapeutic effect of acacetin. Acacetin functional probes were synthesized to capture potential target proteins in RAW264.7 cells. Various small molecule-protein interaction methods were conducted to verify the binding of acacetin to target protein. Molecular docking and site directed mutagenesis tests were performed to analyze the specific binding sites. Co-immunoprecipitation, immunofluorescence assay and western blot were engineered to explore the effect of acacetin on COX-2 degradation by targeting HSP90.
Acacetin specifically binds to the ATP domain of HSP90, to facilitate the dissociation between HSP90 and COX-2, inducing the ubiquitin-degradation of COX-2 in macrophages. Acacetin suppressed the production of pro-inflammatory cytokines, as well as inflammatory related pathways, exerting excellent anti-inflammatory effects in RA.
This research proved that acacetin, a novel HSP90 ATPase inhibitor, inhibits the functional folding of the client protein COX-2, promoting its ubiquitin degradation for anti-inflammation. Targeting HSP90 is a viable strategy to inhibit inflammation, affording a distinct way to managing joint inflammation and pains associated with RA.
炎症在引发和维持类风湿关节炎（RA）中起着重要作用。阿克替宁是一种天然黄酮类化合物，具有出色的抗炎作用，尤其针对 RA。然而，其相关靶点和分子机制仍有待阐明。
本研究旨在探讨阿克替宁在 RA 治疗中的作用机制，寻找 RA 治疗的新靶点。
建立胶原诱导的 RA 小鼠模型，评估阿克替宁的治疗效果。合成阿克替宁功能探针，以捕获 RAW264.7 细胞中潜在的靶蛋白。采用多种小分子-蛋白相互作用方法验证阿克替宁与靶蛋白的结合。进行分子对接和定点突变试验，分析其特异性结合位点。通过共免疫沉淀、免疫荧光和 Western blot 实验，研究阿克替宁通过靶向 HSP90 对 COX-2 降解的影响。
阿克替宁特异性结合 HSP90 的 ATP 结构域，促进 HSP90 与 COX-2 的解离，诱导巨噬细胞中 COX-2 的泛素化降解。阿克替宁抑制促炎细胞因子的产生以及炎症相关通路，在 RA 中表现出优异的抗炎作用。
本研究证明阿克替宁作为一种新型 HSP90 ATP 酶抑制剂，通过抑制靶蛋白 COX-2 的功能折叠，促进其泛素化降解，从而发挥抗炎作用。靶向 HSP90 是抑制炎症的一种可行策略，为管理与 RA 相关的关节炎症和疼痛提供了一种独特的方法。
