Jiang Cuiping, Feng Guangfu, Wang Zhou, Liu Kai, Qu Xinjian, Liu Yonghong, Yi Xiangxi, Gao Chenghai
Institute of Marine Drugs, Faculty of Pharmacy, Guangxi University of Chinese Medicine, No.13 Wuhe Road, Nanning 530200, China.
Guangxi Key Laboratory of Marine Drugs, Institute of Marine Drugs, Faculty of Pharmacy, Guangxi University of Chinese Medicine, No.13 Wuhe Road, Nanning 530200, China.
J Appl Microbiol. 2024 Dec 2;135(12). doi: 10.1093/jambio/lxae297.
The present study aims to investigate the in vitro antifungal activity and mechanism of action of bamemacrolactine C (BAC), a new 24-membered macrolide compound, against Talaromyces marneffei.
The test drug BAC initially demonstrated antifungal activity through a paper disk diffusion assay, followed by determination of the minimum inhibitory concentration value of 35.29 μg ml-1 using microdilution. The association study revealed that combination therapy exhibited additive effects (0.5 < FICI < 1.0) when combined BAC with either amphotericin B or fluconazole. A time-growth assay confirmed that treatment with 35.29 μg ml-1 of BAC completely inhibited the growth of T. marneffei and exhibited antifungal effects. Micromorphological analysis using scanning electron microscopy and transmission electron microscopy photomicrographs revealed that BAC treatment induced morphological damage in fungal cells compared to the control group. Transmembrane protein assays showed a significant reduction in the levels of Na+/K+-ATPase (P < .05) and Ca2+-ATPase (P < .01) compared to the control group. Intracellular enzyme assays demonstrated that BAC treatment significantly decreased ATP, malate dehydrogenase, and succinate dehydrogenase content (P < .01). The combination of proteomics and parallel reaction monitoring (PRM) verification indicated that BAC exhibits an antifungal mechanism against T. marneffei by downregulating ATP citric acid lyase (ACLY) levels , potentially affecting the tricarboxylic acid (TCA) cycle. Besides, the binding model of BAC and the ACLY also shows a good docking score.
The findings suggest that BAC exhibits antifungal activity against T. marneffei, elucidating its multifaceted mechanism of action involving disruption of cell membranes' integrity and inhibition of intracellular enzyme activities, in which the modulation of ACLY in the TCA cycle may play an important role.
本研究旨在探究新型24元大环内酯化合物巴美大环内酯C（BAC）对马尔尼菲篮状菌的体外抗真菌活性及作用机制。
受试药物BAC最初通过纸片扩散法显示出抗真菌活性，随后使用微量稀释法测定其最低抑菌浓度值为35.29μg/ml。联合研究表明，BAC与两性霉素B或氟康唑联合使用时，联合治疗呈现相加作用（0.5＜FICI＜1.0）。时间-生长试验证实，用35.29μg/ml的BAC处理可完全抑制马尔尼菲篮状菌的生长并显示出抗真菌效果。使用扫描电子显微镜和透射电子显微镜照片进行的微观形态分析表明，与对照组相比，BAC处理可诱导真菌细胞发生形态损伤。跨膜蛋白测定显示，与对照组相比，Na+/K+-ATP酶（P＜0.05）和Ca2+-ATP酶（P＜0.01）水平显著降低。细胞内酶测定表明，BAC处理可显著降低ATP、苹果酸脱氢酶和琥珀酸脱氢酶含量（P＜0.01）。蛋白质组学与平行反应监测（PRM）验证相结合表明，BAC通过下调ATP柠檬酸裂解酶（ACLY）水平发挥对马尔尼菲篮状菌的抗真菌机制，可能影响三羧酸（TCA）循环。此外，BAC与ACLY的结合模型也显示出良好的对接分数。
研究结果表明，BAC对马尔尼菲篮状菌具有抗真菌活性，阐明了其多方面的作用机制，包括破坏细胞膜完整性和抑制细胞内酶活性，其中TCA循环中ACLY的调节可能起重要作用。
