Miltefosine Has a Postantifungal Effect and Induces Apoptosis in Cryptococcus Yeasts
Miltefosine Has a Postantifungal Effect and Induces Apoptosis in Cryptococcus Yeasts
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DOI：
10.1128/aac.00312-18
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发表时间：
2018-05
影响因子：
4.9
通讯作者：
C. Spadari;T. Vila;S. Rozental;K. Ishida
中科院分区：
文献类型：
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作者：
C. Spadari;T. Vila;S. Rozental;K. Ishida
隐球菌属是常见的机会性真菌病原体，特别是在艾滋病毒患者中。摘要 隐球菌属。是常见的机会性真菌病原体，特别是在艾滋病毒患者中。已批准的药物米替福辛 (MFS) 有潜力作为隐球菌病的替代抗真菌药物；然而，MFS 在隐球菌中的作用机制尚不清楚。在这里，我们研究了 MFS 对新型隐球菌和格特隐球菌酵母（浮游和生物膜生活方式）的影响，以阐明其作用机制。 MFS 对浮游隐球菌细胞具有抑制和杀菌作用，对分散生物膜细胞具有类似的活性，而固着生物膜细胞对 MFS 不太敏感。有趣的是，MFS 对隐球菌具有抗真菌后作用，在短时间接触杀菌剂量后，增殖延迟长达 8.15 小时。杀真菌浓度下的 MFS 增加了质膜通透性，这可能是由于与麦角甾醇的直接相互作用，正如与外源麦角甾醇的竞争测定所表明的那样。此外，MFS 降低了线粒体膜电位，增加了活性氧 (ROS) 的产生，并诱导 DNA 断裂和浓缩，所有这些都是细胞凋亡的标志。透射电子显微镜分析表明，经 MFS 处理的酵母粘多糖荚膜减少（通过光学显微镜形态测定证实）、质膜不规则、线粒体肿胀和细胞壁不那么明显。我们的结果表明，MFS 通过与麦角甾醇相互作用增加隐球菌的质膜通透性，并且还影响线粒体膜，最终导致细胞凋亡，这与其杀菌活性一致。这些发现证实了 MFS 作为对抗新型隐球菌和格特隐球菌的抗真菌药物的潜力，并需要进一步研究来建立 MFS 对抗隐球菌病的临床方案。
Cryptococcus spp. are common opportunistic fungal pathogens, particularly in HIV patients. ABSTRACT Cryptococcus spp. are common opportunistic fungal pathogens, particularly in HIV patients. The approved drug miltefosine (MFS) has potential as an alternative antifungal against cryptococcosis; however, the mechanism of action of MFS in Cryptococcus is poorly understood. Here, we examined the effects of MFS on C. neoformans and C. gattii yeasts (planktonic and biofilm lifestyles) to clarify its mechanism of action. MFS presented inhibitory and fungicidal effects against planktonic Cryptococcus cells, with similar activities against dispersion biofilm cells, while sessile biofilm cells were less sensitive to MFS. Interestingly, MFS had postantifungal effect on Cryptococcus, with a proliferation delay of up to 8.15 h after a short exposure to fungicidal doses. MFS at fungicidal concentrations increased the plasma membrane permeability, likely due to a direct interaction with ergosterol, as suggested by competition assays with exogenous ergosterol. Moreover, MFS reduced the mitochondrial membrane potential, increased reactive oxygen species (ROS) production, and induced DNA fragmentation and condensation, all of which are hallmarks of apoptosis. Transmission electron microscopy analysis showed that MFS-treated yeasts had a reduced mucopolysaccharide capsule (confirmed by morphometry with light microscopy), plasma membrane irregularities, mitochondrial swelling, and a less conspicuous cell wall. Our results suggest that MFS increases the plasma membrane permeability in Cryptococcus via an interaction with ergosterol and also affects the mitochondrial membrane, eventually leading to apoptosis, in line with its fungicidal activity. These findings confirm the potential of MFS as an antifungal against C. neoformans and C. gattii and warrant further studies to establish clinical protocols for MFS use against cryptococcosis.