Venkata Saibabu, Zeeshan Fatima, Kamal Ahmad, Luqman Ahmad Khan, Saif Hameed
Amity Institute of Biotechnology, Amity University Haryana, Gurugram, India.
Department of Biosciences, Jamia Millia Islamia, New Delhi, India.
Curr Med Mycol. 2020;6(1):1-8. doi: 10.18502/cmm.6.1.2501.
is the fourth most common cause of nosocomial fungal infections across the world. The current drug regimens are suffering from such drawbacks as drug resistance, toxicity, and costliness; accordingly, they highlight the need for the discovery of novel drug agents. The metabolic adaptability under low-carbon conditions and expression of functional virulence traits mark the success of pathogens to cause infection. The metabolic pathways, such as glyoxylate cycle (GC), enable to survive under glucose-deficient conditions prevalent in the hostile niche. Therefore, the key enzymes, namely isocitrate lyase (ICL) and malate synthase (MLS), represent attractive agents against . Similarly, virulence traits, such as morphogenesis and biofilm formation, are the crucial determinants of pathogenicity. Regarding this, the present study was conducted to uncover the role of vanillin (Van), a natural food flavoring agent, in inhibiting GC, yeast-to-hyphal transition, and biofilm formation in human fungal pathogen .
For the determination of hypersensitivity under low-glucose conditions, phenotypic susceptibility assay was utilized. In addition, enzyme activities were estimated based on crude extracts while in-silico binding was confirmed by molecular docking. The assessment of morphogenesis was accomplished using hyphal-inducing media, and biofilm formation was estimated using calcofluor staining, MTT assay, and biomass measurement. Additionally, the in vivo efficacy of Van was demonstrated using nematode model.
Based on the results, Van was found to be a potent GC inhibitor that phenocopied deletion mutant and displayed hypersensitivity under low-carbon conditions. Accordingly, Van facilitated the inhibition of ICL and MLS activities in vitro. Molecular docking analyses revealed the in-silico binding affinity of Van with 1p and 1p. Those analyses were also confirmative of the binding of Van to the active sites of both proteins with better binding energy in comparison to their known inhibitors. Furthermore, Van led to the attenuation of such virulence traits as morphogenesis, biofilm formation, and cell adherence. Finally, the antifungal efficacy of Van was demonstrated by the enhanced survival of with infection. The results also confirmed negligible hemolytic activity on erythrocytes.
As the findings of the present study indicated, Van is a persuasive natural compound that warrants further attention to exploit its anticandidal potential.
是全球医院获得性真菌感染的第四大常见病因。当前的药物治疗方案存在耐药性、毒性和成本高昂等缺点；因此，它们凸显了发现新型药物的必要性。病原体在低碳条件下的代谢适应性和功能性毒力特征的表达标志着其引发感染的成功。诸如乙醛酸循环（GC）等代谢途径使病原体能够在恶劣生态位中普遍存在的葡萄糖缺乏条件下存活。因此，关键酶，即异柠檬酸裂解酶（ICL）和苹果酸合酶（MLS），是对抗病原体的有吸引力的药物靶点。同样，形态发生和生物膜形成等毒力特征是病原体致病性的关键决定因素。鉴于此，本研究旨在揭示天然食品调味剂香草醛（Van）在抑制人类真菌病原体的GC、酵母到菌丝转变以及生物膜形成中的作用。
为了测定低葡萄糖条件下的超敏反应，采用了表型药敏试验。此外，基于粗提物估计酶活性，同时通过分子对接确认计算机模拟结合。使用菌丝诱导培养基完成形态发生评估，使用钙荧光白染色、MTT试验和生物量测量估计生物膜形成。此外，使用线虫模型证明了Van的体内疗效。
基于结果，发现Van是一种有效的GC抑制剂，其表型类似于缺失突变体，并在低碳条件下表现出超敏反应。因此，Van在体外促进了对ICL和MLS活性的抑制。分子对接分析揭示了Van与1p和1p的计算机模拟结合亲和力。这些分析还证实了Van与两种蛋白质活性位点的结合，与已知抑制剂相比具有更好的结合能。此外，Van导致形态发生、生物膜形成和细胞粘附等毒力特征减弱。最后，通过感染线虫后存活率的提高证明了Van的抗真菌疗效。结果还证实了对红细胞的溶血活性可忽略不计。
正如本研究结果所示，Van是一种有说服力的天然化合物，值得进一步关注以开发其抗念珠菌潜力。
