Kohatsu Andréa A N, Silva Flávia A J, Francisco Acácio I, Rimoldi Aline, Silva Marco T A, Vargas Maria D, Rosa João A da, Cicarelli Regina M B
Universidade Estadual Paulista Júlio de Mesquita Filho, Laboratório de Imunologia e Biologia Molecular, Departamento de Ciências Biológicas, Araraquara, SP, Brazil.
Universidade Federal Fluminense, Instituto de Química, Niterói, RJ, Brazil.
Braz J Infect Dis. 2017 Mar-Apr;21(2):125-132. doi: 10.1016/j.bjid.2016.10.010. Epub 2016 Dec 2.
Resistance to benznidazole in certain strains of Trypanosoma cruzi may be caused by the increased production of enzymes that act on the oxidative metabolism, such as mitochondrial tryparedoxin peroxidase which catalyses the reduction of peroxides. This work presents cytotoxicity assays performed with ferrocenyl diamine hydrochlorides in six different strains of T. cruzi epimastigote forms (Y, Bolivia, SI1, SI8, QMII, and SIGR3). The last four strains have been recently isolated from triatominae and mammalian host (domestic cat). The expression of mitochondrial tryparedoxin peroxidase was analyzed by the Western blotting technique using polyclonal antibody anti mitochondrial tryparedoxin peroxidase obtained from a rabbit immunized with the mitochondrial tryparedoxin peroxidase recombinant protein. All the tested ferrocenyl diamine hydrochlorides were more cytotoxic than benznidazole. The expression of the 25.5kDa polypeptide of mitochondrial tryparedoxin peroxidase did not increase in strains that were more resistant to the ferrocenyl compounds (SI8 and SIGR3). In addition, a 58kDa polypeptide was also recognized in all strains. Ferrocenyl diamine hydrochlorides showed trypanocidal activity and the expression of 25.5kDa mitochondrial tryparedoxin peroxidase is not necessarily increased in some T. cruzi strains. Most likely, other mechanisms, in addition to the over expression of this antioxidative enzyme, should be involved in the escape of parasites from cytotoxic oxidant agents.
克氏锥虫某些菌株对苯硝唑产生抗性，可能是由于作用于氧化代谢的酶产量增加，比如催化过氧化物还原的线粒体锥虫硫氧还蛋白过氧化物酶。本研究对六种不同的克氏锥虫前鞭毛体形式（Y、玻利维亚、SI1、SI8、QMII和SIGR3）进行了二茂铁基二胺盐酸盐的细胞毒性试验。后四种菌株最近从锥蝽和哺乳动物宿主（家猫）中分离得到。使用从用线粒体锥虫硫氧还蛋白过氧化物酶重组蛋白免疫的兔子获得的抗线粒体锥虫硫氧还蛋白过氧化物酶多克隆抗体，通过蛋白质印迹技术分析线粒体锥虫硫氧还蛋白过氧化物酶的表达。所有测试的二茂铁基二胺盐酸盐的细胞毒性均高于苯硝唑。在对二茂铁基化合物更具抗性的菌株（SI8和SIGR3）中，线粒体锥虫硫氧还蛋白过氧化物酶25.5kDa多肽的表达并未增加。此外，在所有菌株中还识别出一种58kDa的多肽。二茂铁基二胺盐酸盐显示出杀锥虫活性，并且在某些克氏锥虫菌株中，25.5kDa线粒体锥虫硫氧还蛋白过氧化物酶的表达不一定会增加。很可能，除了这种抗氧化酶的过表达之外，其他机制也应参与寄生虫从细胞毒性氧化剂中逃逸的过程。
