香草醛抗真菌作用的机制研究揭示了其对细胞表面完整性和线粒体功能的破坏。
Mechanistic Insights into the Anticandidal Action of Vanillin Reveal Disruption of Cell Surface Integrity and Mitochondrial Functioning.
机构信息
Amity Institute of Biotechnology, Amity University Haryana, Gurugram (Manesar)-122413, India.
Department of Biosciences, Jamia Millia Islamia, New Delhi-110025, India.
出版信息
Infect Disord Drug Targets. 2021;21(3):405-415. doi: 10.2174/1871526520666200702134110.
BACKGROUND
Considering the emergence of multidrug resistance (MDR) in prevalent human fungal pathogen, Candida albicans, there is a parallel spurt in the development of novel strategies aimed to disrupt MDR. Compounds from natural resources could be exploited as efficient antifungal drugs owing to their structural diversity, cost effectiveness and negligible side effects.
OBJECTIVE
The present study elucidates the antifungal mechanisms of Vanillin (Van), a natural food flavoring agent against Candida albicans.
METHODS
Antifungal activities were assessed by broth microdilution and spot assays. Membrane and cell wall perturbations were studied by PI uptake, electron microscopy, plasma membrane H+ extrusion activity and estimation of ergosterol and chitin contents. Mitochondrial functioning was studied by growth on non-fermentable carbon sources, rhodamine B labeling and using retrograde signaling mutants. Gene expressions were validated by semi-quantitative RT-PCR.
RESULTS
We observed that the antifungal activity of Van was not only limited to clinical isolates of C. albicans but also against non-albicans species of Candida. Mechanistic insights revealed the effect of Van on cell surface integrity as evident from hypersensitivity against membrane perturbing agent SDS, depleted ergosterol levels, transmission electron micrographs and diminished plasma membrane H+ extrusion activity. In addition, spot assays with cell wall perturbing agents, scanning electron micrographs, delayed sedimentation rate and lower chitin content further substantiate cell wall damage by Van. Furthermore, Van treated cells underwent mitochondrial dysfunctioning via impaired retrograde signaling leading to abrogated iron homeostasis and DNA damage. All the perturbed phenotypes were also validated by RT-PCR depicting differential regulation of genes (NPC2, KRE62, FTR2 and CSM3) in response to Van.
CONCLUSION
Together, our results suggested that Van is promising antifungal agent that may be advocated for further investigation in therapeutic strategies to treat Candida infections.
背景
鉴于流行的人类真菌病原体白色念珠菌出现多药耐药性（MDR），人们正在并行开发旨在破坏 MDR 的新策略。由于结构多样性、成本效益和副作用极小，天然资源中的化合物可以被开发为有效的抗真菌药物。
目的
本研究阐明了天然食品调味剂香草醛（Van）抗白色念珠菌的抗真菌机制。
方法
通过肉汤微量稀释和点样测定评估抗真菌活性。通过 PI 摄取、电子显微镜、质膜 H+外排活性以及麦角固醇和几丁质含量的测定研究膜和细胞壁的扰动。通过在非发酵碳源上生长、罗丹明 B 标记和使用逆行信号突变体研究线粒体功能。通过半定量 RT-PCR 验证基因表达。
结果
我们观察到，Van 的抗真菌活性不仅限于白色念珠菌的临床分离株，还对非白色念珠菌属的念珠菌有效。机制研究表明，Van 对细胞表面完整性有影响，这表现在对膜扰动剂 SDS 的超敏反应、麦角固醇水平降低、透射电子显微镜和质膜 H+外排活性降低。此外，用细胞壁扰动剂进行点样测定、扫描电子显微镜、延迟沉降率和较低的几丁质含量进一步证实了 Van 引起的细胞壁损伤。此外，Van 处理的细胞通过受损的逆行信号导致铁稳态和 DNA 损伤受损而发生线粒体功能障碍。通过 RT-PCR 也验证了所有受干扰的表型，表明基因（NPC2、KRE62、FTR2 和 CSM3）对 Van 有差异调节。
结论
综上所述，我们的结果表明，Van 是一种很有前途的抗真菌药物，可能被倡导用于进一步研究治疗念珠菌感染的治疗策略。
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