Trypanosoma cruzi mitochondrial swelling and membrane potential collapse as primary evidence of the mode of action of naphthoquinone analogues

BMC Microbiology

Research Article

Maria Teresa Molina¹  Natalia A De Santana²  Solange L De Castro²  Rubem F S Menna-Barreto²  Kelly Salomão² 

[1] Instituto de Química Médica, CSIC, Juan de la Cierva 3, 28006, Madrid, Spain;Laboratório de Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Av. Brasil 4365, 21040-900, Manguinhos, Rio de Janeiro, RJ, Brazil;

关键词: Rypanosoma cruzi;    Naphthoquinones;    Juglone;    Experimental chemotherapy;    Mitochondria;   

DOI  :  10.1186/1471-2180-13-196

 received in 2013-05-09, accepted in 2013-08-30,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundNaphthoquinones (NQs) are privileged structures in medicinal chemistry due to the biological effects associated with the induction of oxidative stress. The present study evaluated the activities of sixteen NQs derivatives on Trypanosoma cruzi.ResultsFourteen NQs displayed higher activity against bloodstream trypomastigotes of T. cruzi than benznidazole. Further assays with NQ1, NQ8, NQ9 and NQ12 showed inhibition of the proliferation of axenic epimastigotes and intracelulluar amastigotes interiorized in macrophages and in heart muscle cells. NQ8 was the most active NQ against both proliferative forms of T. cruzi. In epimastigotes the four NQs induced mitochondrial swelling, vacuolization, and flagellar blebbing. The treatment with NQs also induced the appearance of large endoplasmic reticulum profiles surrounding different cellular structures and of myelin-like membranous contours, morphological characteristics of an autophagic process. At IC50 concentration, NQ8 totally disrupted the ΔΨm of about 20% of the parasites, suggesting the induction of a sub-population with metabolically inactive mitochondria. On the other hand, NQ1, NQ9 or NQ12 led only to a discrete decrease of TMRE + labeling at IC50 values. NQ8 led also to an increase in the percentage of parasites labeled with DHE, indicative of ROS production, possibly the cause of the observed mitochondrial swelling. The other three NQs behaved similarly to untreated controls.ConclusionsNQ1, NQ8, NQ9 and NQ12 induce an autophagic phenotype in T. cruzi epimastigoted, as already observed with others NQs. The absence of oxidative stress in NQ1-, NQ9- and NQ12-treated parasites could be due to the existence of more than one mechanism of action involved in their trypanocidal activity, leaving ROS generation suppressed by the detoxification system of the parasite. The strong redox effect of NQ8 could be associated to the presence of the acetyl group in its structure facilitating quinone reduction, as previously demonstrated by electrochemical analysis. Further experiments using biochemical and molecular approaches are needed to better characterize ROS participation in the mechanism of action of these NQs.

【 授权许可】

Unknown   
© Salomão et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.