Ben Yaakov Dafna, Rivkin Anna, Mircus Gabriel, Albert Nathaniel, Dietl Anna-Maria, Kovalerchick Dimitry, Carmeli Shmuel, Haas Hubertus, Kontoyiannis Dimitrios P, Osherov Nir
Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
Department of Infectious Diseases, Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, TX, USA.
J Antimicrob Chemother. 2016 Apr;71(4):946-52. doi: 10.1093/jac/dkv446. Epub 2016 Jan 7.
During recent decades, the number of invasive fungal infections among immunosuppressed patients has increased significantly, whereas the number of effective systemic antifungal drugs remains low and unsatisfactory. The aim of this study was to characterize a novel antifungal compound, CW-8/haemofungin, which we previously identified in a screen for compounds affecting fungal cell wall integrity.
The in vitro characteristics of haemofungin were investigated by MIC evaluation against a panel of pathogenic and non-pathogenic fungi, bacteria and mammalian cells in culture. Haemofungin mode-of-action studies were performed by screening an Aspergillus nidulans overexpression genomic library for resistance-conferring plasmids and biochemical validation of the target. In vivo efficacy was tested in the Galleria mellonella and Drosophila melanogaster insect models of infection.
We demonstrate that haemofungin causes swelling and lysis of growing fungal cells. It inhibits the growth of pathogenic Aspergillus, Candida, Fusarium and Rhizopus isolates at micromolar concentrations, while only weakly affecting the growth of mammalian cell lines. Genetic and biochemical analyses in A. nidulans and Aspergillus fumigatus indicate that haemofungin primarily inhibits ferrochelatase (HemH), the last enzyme in the haem biosynthetic pathway. Haemofungin was non-toxic and significantly reduced mortality rates of G. mellonella and D. melanogaster infected with A. fumigatus and Rhizopus oryzae, respectively.
Further development and in vivo validation of haemofungin is warranted.
在最近几十年中，免疫抑制患者侵袭性真菌感染的数量显著增加，而有效的全身性抗真菌药物数量仍然很少且不尽人意。本研究的目的是对一种新型抗真菌化合物CW-8/血真菌素进行特性描述，我们之前在筛选影响真菌细胞壁完整性的化合物时鉴定出了该化合物。
通过对一组致病性和非致病性真菌、细菌及培养中的哺乳动物细胞进行MIC评估，研究血真菌素的体外特性。通过筛选构巢曲霉过表达基因组文库以寻找赋予抗性的质粒并对靶点进行生化验证，开展血真菌素作用机制研究。在感染的大蜡螟和黑腹果蝇昆虫模型中测试体内疗效。
我们证明血真菌素会导致生长中的真菌细胞肿胀和裂解。它在微摩尔浓度下可抑制致病性曲霉、念珠菌、镰刀菌和根霉菌株的生长，而对哺乳动物细胞系的生长影响微弱。在构巢曲霉和烟曲霉中进行的遗传和生化分析表明，血真菌素主要抑制血红素生物合成途径中的最后一种酶——亚铁螯合酶（HemH）。血真菌素无毒，并且分别显著降低了感染烟曲霉和米根霉的大蜡螟和黑腹果蝇的死亡率。
有必要对血真菌素进行进一步开发和体内验证。
