Mitochondrial dysfunction on Leishmania (Leishmania) amazonensis induced by ketoconazole: insights into drug mode of action

BACKGROUND: Leishmania parasites cause leishmaniasis that range from self-limiting cutaneous lesions to more serious forms of the disease. The search for potential drug targets focusing on biochemical and metabolic pathways revealed the sterol biosynthesis inhibitors (SBIs) as a promising approach. In this class of inhibitors is found ketoconazole, a classical inhibitor of 14α-methysterol 14-demethylase. OBJECTIVE: The present study aimed to better understand the biological response of Leishmania (Leishmania) amazonensis promastigotes at the cellular level after ketoconazole treatment. METHODS: Herein, techniques, such as fluorimetry, flow cytometry, fluorescence microscopy, electron and scanning microscopy were used to investigate the cellular structures and to identify organelles affected by ketoconazole treatment. FINDINGS: The study demonstrated, for the first time, the effect of ketoconazole on mitochondrion functioning and its probable relationship to cell cycle and death on L. (L.) amazonensis promastigotes (IFLA/BR/67/PH8 strain). MAIN CONCLUSIONS: Ketoconazole-induced mitochondrial damages led to hyperpolarisation of this single organelle and autophagic vacuoles formation, as a parasite survival strategy. These damages did not reflect directly on the parasite cell cycle, but drove the parasites to death, making them susceptible to ketoconazole treatment in in vitro models.