title: The production of reactive oxygen species is a universal action mechanism of Amphotericin B against pathogenic yeasts and contributes to the fungicidal effect of this drug.
abstract: Amphotericin B (AMB) is an antifungal drug that binds to ergosterol and forms pores at the cell membrane, causing the loss of ions. In addition, AMB induces the accumulation of reactive oxygen species (ROS), and although these molecules have multiple deleterious effects on fungal cells, their specific role in the action mechanism of AMB remains unknown. In this work, we studied the role of ROS in the action mechanism of AMB. We determined the intracellular induction of ROS in 44 isolates of different pathogenic yeast species (Candida albicans, Candida parapsilosis, Candida glabrata, Candida tropicalis, Candida krusei, Cryptococcus neoformans, and Cryptococcus gattii). We also characterized the production of ROS in AMB-resistant isolates. We found that AMB induces the formation of ROS in all the species tested. The inhibition of the mitochondrial respiratory chain by rotenone blocked the induction of ROS by AMB and provided protection from the killing action of the antifungal. Moreover, this phenomenon was absent in strains that displayed resistance to AMB. These strains showed an alteration in the respiration rate and mitochondrial membrane potential and also had higher catalase activity than that of the AMB-susceptible strains. Consistently, AMB failed to induce protein carbonylation in the resistant strains. Our data demonstrate that the production of ROS by AMB is a universal and important action mechanism that is correlated with the fungicidal effect and might explain the low rate of resistance to the molecule. Finally, these data provide an opportunity to design new strategies to improve the efficacy of this antifungal.
authors.affiliation: Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain Group of Investigative Dermatology, University of Antioquia, Medellín, Colombia.
authors.forename: Ana Cecilia
authors.initials: AC
authors.lastname: Mesa-Arango
authors.affiliation: Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain.
authors.forename: Nuria
authors.initials: N
authors.lastname: Trevijano-Contador
authors.affiliation: Department of Microbiology II, Faculty of Pharmacy, Complutense University of Madrid, Madrid, Spain.
authors.forename: Elvira
authors.initials: E
authors.lastname: Román
authors.affiliation: Department of Microbiology, Biology School, University of Murcia, Murcia, Spain.
authors.forename: Ruth
authors.initials: R
authors.lastname: Sánchez-Fresneda
authors.affiliation: Department of Basic Medical Sciences, IRBLleida, Universitat de Lleida, Lleida, Spain.
authors.forename: Celia
authors.initials: C
authors.lastname: Casas
authors.affiliation: Department of Basic Medical Sciences, IRBLleida, Universitat de Lleida, Lleida, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Herrero
authors.affiliation: Department of Microbiology, Biology School, University of Murcia, Murcia, Spain.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Argüelles
authors.affiliation: Department of Microbiology II, Faculty of Pharmacy, Complutense University of Madrid, Madrid, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Pla
authors.affiliation: Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Cuenca-Estrella
authors.affiliation: Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain ozaragoza@isciii.es.
authors.forename: Oscar
authors.initials: O
authors.lastname: Zaragoza
mesh_terms: D000666:Amphotericin B / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology*; D002175:Candida / Q000187:drug effects* / Q000235:genetics; D002177:Candidiasis / Q000188:drug therapy / Q000235:genetics / Q000382:microbiology; D002374:Catalase / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects; D003453:Cryptococcosis / Q000188:drug therapy / Q000382:microbiology; D003454:Cryptococcus / Q000187:drug effects*; D025141:Drug Resistance, Fungal; D004579:Electron Transport / Q000187:drug effects; D004875:Ergosterol / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D018384:Oxidative Stress / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012402:Rotenone / Q000494:pharmacology; D014475:Uncoupling Agents / Q000494:pharmacology
chemical_list: D000935:Antifungal Agents; D017382:Reactive Oxygen Species; D014475:Uncoupling Agents; D012402:Rotenone; D000666:Amphotericin B; D002374:Catalase; D004875:Ergosterol