Amphotericin B mediates killing in Cryptococcus neoformans through the induction of a strong oxidative burst

ABSTRACT: We studied the effects of Amphotericin B (AmB) on Cryptococcus neoformans using different viability methods (CFUs enumeration, XTT assay and propidium iodide permeability). After 1 h of incubation, there were no viable colonies when the cells were exposed to AmB concentrations 1 mg/L. In the same conditions, the cells did not become permeable to propidium iodide, a phenomenon that was not observed until 3 h of incubation. When viability was measured in parallel using XTT assay, a result consistent with the CFUs was obtained, although we also observed a paradoxical effect in which at high AmB concentrations, a higher XTT reduction was measured than at intermediate AmB concentrations. This paradoxical effect was not observed after 3 h of incubation with AmB, and lack of XTT reduction was observed at AmB concentrations higher than 1 mg/L. When stained with dihydrofluorescein, AmB induced a strong intracellular oxidative burst. Consistent with oxidative damage, AmB induced protein carbonylation. Our results indicate that in C. neoformans, Amphotericin B causes intracellular damage mediated through the production of free radicals before damage on the cell membrane, measured by propidium iodide uptake.

• Autores: Mesa Arango, Ana Cecilia; Casas, Celia; Cuenca Estrella, Manuel; Gianinni Soares Mendes, María José; Herrero, Enrique; Rodríguez Tudela, Juan Luis; Sangalli Leite, Fernanda; Scorzoni, Liliana; Zaragoza, Oscar
• Tipo de recurso: Article of investigation
• Fecha de publicación: 2011
• Institución: Universidad de Antioquia
• Repositorio: Repositorio UdeA
• Idioma: eng
• OAI Identifier: oai:bibliotecadigital.udea.edu.co:10495/41217
• Acceso en línea: https://hdl.handle.net/10495/41217
• Palabra clave: Anfotericina B; Amphotericin B; Antifúngicos; Antifungal Agents; Membrana Celular; Cell Membrane; Recuento de Colonia Microbiana; Colony Count, Microbial; Cryptococcus neoformans; Pruebas de Sensibilidad Microbiana; Microbial Sensitivity Tests; Oxidación-Reducción; Oxidation-Reduction; Propidio; Propidium; Estallido Respiratorio; Respiratory Burst; https://id.nlm.nih.gov/mesh/D000666; https://id.nlm.nih.gov/mesh/D000935; https://id.nlm.nih.gov/mesh/D002462; https://id.nlm.nih.gov/mesh/D015169; https://id.nlm.nih.gov/mesh/D003455; https://id.nlm.nih.gov/mesh/D008826; https://id.nlm.nih.gov/mesh/D010084; https://id.nlm.nih.gov/mesh/D011419; https://id.nlm.nih.gov/mesh/D016897
• Rights: openAccess
• License: http://creativecommons.org/licenses/by-nc/2.5/co/