Requirement for Ergosterol in V-ATPase Function Underlies Antifungal Activity of Azole Drugs

PLoS Pathogens

David S. Perlin¹  Steven Park¹  Soledad Gamarra¹  Guillermo Garcia-Effron¹  Rajini Rao²  Yong-Qiang Zhang² 

[1] Public Health Research Institute, New Jersey Medical School-UMDNJ, Newark, New Jersey, United States of America;The Johns Hopkins University School of Medicine of Baltimore, Maryland, United States of America

关键词: Azoles;    Vesicles;    C;    ida albicans;    Homeostasis;    Antifungals;    Sterols;    Saccharomyces cerevisiae;    Biosynthesis;   

DOI  :  10.1371/journal.ppat.1000939

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Ergosterol is an important constituent of fungal membranes. Azoles inhibit ergosterol biosynthesis, although the cellular basis for their antifungal activity is not understood. We used multiple approaches to demonstrate a critical requirement for ergosterol in vacuolar H+-ATPase function, which is known to be essential for fungal virulence. Ergosterol biosynthesis mutants of S. cerevisiae failed to acidify the vacuole and exhibited multiple vma− phenotypes. Extraction of ergosterol from vacuolar membranes also inactivated V-ATPase without disrupting membrane association of its subdomains. In both S. cerevisiae and the fungal pathogen C. albicans, fluconazole impaired vacuolar acidification, whereas concomitant ergosterol feeding restored V-ATPase function and cell growth. Furthermore, fluconazole exacerbated cytosolic Ca2+ and H+ surges triggered by the antimicrobial agent amiodarone, and impaired Ca2+ sequestration in purified vacuolar vesicles. These findings provide a mechanistic basis for the synergy between azoles and amiodarone observed in vitro. Moreover, we show the clinical potential of this synergy in treatment of systemic fungal infections using a murine model of Candidiasis. In summary, we demonstrate a new regulatory component in fungal V-ATPase function, a novel role for ergosterol in vacuolar ion homeostasis, a plausible cellular mechanism for azole toxicity in fungi, and preliminary in vivo evidence for synergism between two antifungal agents. New insights into the cellular basis of azole toxicity in fungi may broaden therapeutic regimens for patient populations afflicted with systemic fungal infections.

【 授权许可】

CC BY