Zhu Shuyue, Hu Chunjie, Wang Yan, Jin Mengli, Zhang Qiuyue, Han Shaoyu, Tang Yating, Wu Desheng, Fu Di, Jiang Shuang, Song Danning, Wei Lin, Song Wu, Zhang Chi, Zhang Wenfeng
Changchun University of Chinese Medicine, Changchun, 130117, China.
Proctology Department, Affiliated Hospital of Changchun University of Chinese Medicine, Changchun, 130117, China.
Biochimie. 2025 Feb;229:84-94. doi: 10.1016/j.biochi.2024.10.010. Epub 2024 Oct 18.
The increasing prevalence of antibiotic-resistant bacteria, represented by Methicillin-resistant Staphylococcus aureus (MRSA), has necessitated a shift towards anti-virulence strategies in treatment approaches. This research demonstrated that daphnetin effectively disrupted MRSA virulence by targeting Sortase A (SrtA), an enzyme in Staphylococcus aureus (S. aureus) responsible for adhesion and invasion, as well as the toxin α-hemolysin (Hla) that leads to cell lysis. Utilizing Fluorescence Resonance Energy Transfer, daphnetin showed direct inhibitory effect on SrtA activity, with an IC of 25.98 μg/mL. Additionally, daphnetin hindered various SrtA-mediated processes in S. aureus, such as fibronectin adherence, A549 cell invasion, biofilm formation, and bacterial motility. Daphnetin inhibited S. aureus-induced hemolysis and reduced Hla expression as confirmed by Western blot analysis. Molecular docking studies identified specific binding sites of daphnetin with SrtA, highlighting key amino acid residues like GLU-77, TYR-75, and LYS-145, with a docking score of -7.139 kcal/mol. Besides that, daphnetin exhibited a protective effect on MRSA-induced pneumonia in vivo. In summary, daphnetin, a natural compound, effectively inhibited SrtA and Hla activities, attenuating MRSA virulence and showcasing potential for treating bacterial infections.
以耐甲氧西林金黄色葡萄球菌（MRSA）为代表的抗生素耐药菌的日益流行，使得治疗方法必须转向抗毒力策略。本研究表明，瑞香素通过靶向分选酶A（SrtA）有效破坏MRSA的毒力，SrtA是金黄色葡萄球菌中一种负责黏附和侵袭的酶，以及导致细胞裂解的毒素α-溶血素（Hla）。利用荧光共振能量转移技术，瑞香素对SrtA活性表现出直接抑制作用，IC50为25.98μg/mL。此外，瑞香素阻碍了金黄色葡萄球菌中各种SrtA介导的过程，如纤连蛋白黏附、A549细胞侵袭、生物膜形成和细菌运动。瑞香素抑制了金黄色葡萄球菌诱导的溶血，并通过蛋白质免疫印迹分析证实降低了Hla的表达。分子对接研究确定了瑞香素与SrtA的特异性结合位点，突出了关键氨基酸残基如GLU-77、TYR-75和LYS-145，对接分数为-7.139 kcal/mol。除此之外，瑞香素在体内对MRSA诱导的肺炎表现出保护作用。总之，瑞香素这种天然化合物有效抑制了SrtA和Hla的活性，减弱了MRSA的毒力，并展示了治疗细菌感染的潜力。
