Maurya Indresh Kumar, Thota Chaitanya Kumar, Sharma Jyotsna, Tupe Santosh Genba, Chaudhary Preeti, Singh Manoj Kumar, Thakur Indu Shekhar, Deshpande Mukund, Prasad Rajendra, Chauhan Virander Singh
Membrane Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
Biochim Biophys Acta. 2013 Nov;1830(11):5193-203. doi: 10.1016/j.bbagen.2013.07.016. Epub 2013 Jul 20.
Three de novo designed low molecular weight cationic peptides (IJ2, IJ3 and IJ4) containing an unnatural amino acid α,β-didehydrophenylalanine (∆Phe) exhibited potent antifungal activity against fluconazole (FLC) sensitive and resistant clinical isolates of Candida albicans as well as non-albicans and other yeast and filamentous pathogenic fungi. In the present study, their synthesis, susceptibility of different fungi and the mechanism of anti-candidal action have been elucidated.
The antimicrobial peptides (AMPs) were synthesized by solid-phase method and checked for antifungal activity against different yeasts and fungi by broth microdilution method. Anti-candidal mode of action of the peptides was investigated through detecting membrane permeabilization by confocal microscopy, Reactive Oxygen Species (ROS) generation by fluorometry, apoptosis and necrosis by flow cytometry and cell wall damage using Scanning and Transmission Electron Microscopy.
The MIC of the peptides against C. albicans and other yeast and filamentous fungal pathogens ranged between 3.91 and 250μM. All three peptides exhibited effect on multiple targets in C. albicans including disruption of cell wall structures, compromised cell membrane permeability leading to their enhanced entry into the cells, accumulation of ROS and induction of apoptosis. The peptides also showed synergistic effect when used in combination with fluconazole (FLC) and caspofungin (CAS) against C. albicans.
The study suggests that the AMPs alone or in combination with conventional antifungals hold promise for the control of fungal pathogens, and need to be further explored for treatment of fungal infections.
三种新设计的含有非天然氨基酸α,β-二脱氢苯丙氨酸（∆Phe）的低分子量阳离子肽（IJ2、IJ3和IJ4）对氟康唑（FLC）敏感和耐药的白色念珠菌临床分离株以及非白色念珠菌和其他酵母及丝状致病真菌表现出强大的抗真菌活性。在本研究中，已阐明了它们的合成、对不同真菌的敏感性以及抗念珠菌作用机制。
通过固相法合成抗菌肽（AMPs），并采用肉汤微量稀释法检测其对不同酵母和真菌的抗真菌活性。通过共聚焦显微镜检测膜通透性、荧光法检测活性氧（ROS）生成、流式细胞术检测凋亡和坏死以及使用扫描和透射电子显微镜检测细胞壁损伤，研究了肽的抗念珠菌作用模式。
这些肽对白色念珠菌以及其他酵母和丝状真菌病原体的最低抑菌浓度（MIC）在3.91至250μM之间。所有三种肽对白色念珠菌的多个靶点都有作用，包括破坏细胞壁结构、损害细胞膜通透性导致其更多地进入细胞、ROS积累和诱导凋亡。这些肽与氟康唑（FLC）和卡泊芬净（CAS）联合使用时对白色念珠菌也显示出协同作用。
该研究表明，抗菌肽单独使用或与传统抗真菌药物联合使用有望控制真菌病原体，并且需要进一步探索用于治疗真菌感染。
