Lichen endophyte derived pyridoxatin inactivates Candida growth by interfering with ergosterol biosynthesis
Lichen endophyte derived pyridoxatin inactivates Candida growth by interfering with ergosterol biosynthesis
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地衣内生菌衍生的吡哆素通过干扰麦角甾醇生物合成来灭活念珠菌生长
DOI：
10.1016/j.bbagen.2015.05.005
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发表时间：
2015-09-01
影响因子：
3
通讯作者：
Lou, Hongxiang
中科院分区：
文献类型：
--
作者：
Chang, Wenqiang;Zhang, Ming;Lou, Hongxiang
背景：本研究是表征pyridoxatin （PYR）的抗真菌作用，PYR是一种从内生真菌中分离出来的小天然产物。方法：以秀丽隐杆线虫为感染模型，进行体外和体内药敏试验，评价PYR对念珠菌的抑菌效果。采用MTT法检测PYR对人正常细胞的细胞毒性。采用实时定量PCR （real-time quantitative PCR, qPCR）检测甾醇合成和细胞周期调控相关基因的转录水平。采用液相色谱/串联质谱法（LC/MS）检测麦角甾醇、角鲨烯、羊毛甾醇的含量。结果：PYR对4种被试念珠菌有效，其最低抑菌浓度（mic）在1 ~ 4 μ g/ml之间。PYR对正常人细胞无明显的细胞毒性作用。PYR抑制白色念珠菌的生长，阻止生物膜的形成。而抗真菌作用不依赖于外排泵。体内实验表明，PYR可显著延长感染秀丽隐杆线虫的存活时间。qPCR结果显示，在pyr处理的细胞中，大多数与甾醇生物合成相关的基因显著下调。甾醇含量测定发现，PYR对麦角甾醇合成有剂量依赖性抑制作用，并引起角鲨烯和羊毛甾醇的积累。此外，构效关系分析表明，PYR中的杂环羟基肟酸是其抗真菌作用的关键基团。结论：PYR干扰麦角甾醇的合成，发挥抗真菌作用。一般意义：阐明的机制为PYR在抗临床相关真菌感染中的应用提供了可能。(C) 2015 Elsevier B.V.版权所有
Background: This study is to characterize the antifungal effects of pyridoxatin (PYR), a small natural product isolated from an endolichenic fungus.Methods: The susceptibility tests in vitro and in vivo by using Caenorhabditis elegans as an infectious model were performed to evaluate the antifungal efficacy of PYR against Candida species. The cytotoxicity of PYR against normal human cells was tested using MTT assay. The transcriptional levels of genes related to sterol synthesis and cell cycle regulation were measured using real-time quantitative PCR (qPCR). The contents ergosterol, squalene, lanosterol were detected by liquid chromatography/tandem mass spectrometry (LC/MS).Results: PYR was effective against four tested Candida species with its minimal inhibitory concentrations (MICs) ranging from 1-4 mu g/ml. No obvious cytotoxicity was observed for PYR against normal human cells. PYR inhibited the growth of Candida albicans, preventing the biofilm formation. And the antifungal action was independent on efflux pumps. The in vivo test showed PYR greatly prolonged the survival of infected C. elegans. qPCR results revealed that most of the genes related to sterol biosynthesis were considerably down-regulated in PYR-treated cells. Determination of the sterol content found that PYR inhibited the ergosterol synthesis dose dependently and caused the accumulation of squalene and lanosterol. Moreover, analysis of the structure-activity relationship revealed the heterocyclic hydroxamic acid in PYR was the key group for the antifungal action.Conclusions: PYR interferes with the ergosterol synthesis to exert antifungal action.General significance: The elucidated mechanism provides possible applications of PYR in fighting clinical relevant fungal infections. (C) 2015 Elsevier B.V. All rights reserved.