Instituto de Patología Experimental, Universidad Nacional de Salta - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Salta, Argentina.
Instituto de Agrobiotecnología del Litoral, Universidad Nacional del Litoral - CONICET, Santa Fe, Argentina.
Free Radic Biol Med. 2019 Jan;130:23-34. doi: 10.1016/j.freeradbiomed.2018.10.436. Epub 2018 Oct 23.
Chagas cardiomyopathy, caused by Trypanosoma cruzi infection, continues to be a neglected illness, and has a major impact on global health. The parasite undergoes several stages of morphological and biochemical changes during its life cycle, and utilizes an elaborated antioxidant network to overcome the oxidants barrier and establish infection in vector and mammalian hosts. Trypanothione synthetase (TryS) catalyzes the biosynthesis of glutathione-spermidine adduct trypanothione (T(SH)) that is the principal intracellular thiol-redox metabolite in trypanosomatids.
We utilized genetic overexpression (TryS) and pharmacological inhibition approaches to examine the role of TryS in T. cruzi proliferation, tolerance to oxidative stress and resistance to anti-protozoal drugs. Our data showed the expression and activity of TryS was increased in all morphological stages of TryS (vs. control) parasites. In comparison to controls, the TryS epimastigotes (insect stage) recorded shorter doubling time, and both epimastigotes and infective trypomastigotes of TryS exhibited 36-71% higher resistance to HO (50-1000 μM) and heavy metal (1-500 μM) toxicity. Treatment with TryS inhibitors (5-30 μM) abolished the proliferation and survival advantages against HO pressure in a dose-dependent manner in both TryS and control parasites. Further, epimastigote and trypomastigote forms of TryS (vs. control) T. cruzi tolerated higher doses of benznidazole and nifurtimox, the drugs currently administered for acute Chagas disease treatment.
TryS is essential for proliferation and survival of T. cruzi under normal and oxidant stress conditions, and provides an advantage to the parasite to develop resistance against currently used anti-trypanosomal drugs. TryS indispensability has been chemically validated with inhibitors that may be useful for drug combination therapy against Chagas disease.
克氏锥虫感染引起的恰加斯心肌病仍然是一种被忽视的疾病，对全球健康有重大影响。寄生虫在其生命周期中经历了几个形态和生化变化的阶段，并利用一个精心设计的抗氧化网络来克服氧化剂屏障，并在媒介和哺乳动物宿主中建立感染。硫醇合成酶（TryS）催化谷胱甘肽-亚精胺加合物硫醇（T（SH））的生物合成，该化合物是原生动物中的主要细胞内硫醇-氧化还原代谢物。
我们利用遗传过表达（TryS）和药理学抑制方法来研究 TryS 在 T. cruzi 增殖、对氧化应激的耐受和对抗原生动物药物的抗性中的作用。我们的数据表明，TryS 在 TryS（与对照相比）寄生虫的所有形态阶段的表达和活性都增加了。与对照相比，TryS 无鞭毛体（昆虫阶段）记录的倍增时间更短，TryS 的无鞭毛体和感染性锥鞭毛体对 HO（50-1000 μM）和重金属（1-500 μM）毒性的抗性分别提高了 36-71%。TryS 抑制剂（5-30 μM）以剂量依赖性方式处理 TryS 和对照寄生虫，均可消除对 HO 压力的增殖和生存优势。此外，TryS（与对照相比）T. cruzi 的无鞭毛体和锥鞭毛体形式耐受更高剂量的苯并咪唑和硝呋替莫，这两种药物目前用于急性恰加斯病的治疗。
TryS 对 T. cruzi 在正常和氧化应激条件下的增殖和存活是必不可少的，并为寄生虫提供了对目前用于抗原生动物药物产生抗性的优势。TryS 的不可或缺性已通过抑制剂进行了化学验证，这些抑制剂可能对针对恰加斯病的联合药物治疗有用。
