Núcleo de Pesquisas Em Parasitologia, Departamento de Parasitologia, Microbiologia e Imunologia, I.C.B., Universidade Federal de Juiz de Fora, Campus Universitário, Juiz de Fora, Minas Gerais, Brazil.
SINTBIOMOL, Departamento de Química, I.C.E., Universidade Federal de Juiz de Fora, Campus Universitário, Juiz de Fora, Minas Gerais, Brazil.
Parasitol Res. 2022 May;121(5):1389-1406. doi: 10.1007/s00436-022-07431-9. Epub 2022 Feb 16.
Visceral leishmaniasis (VL) is the most severe clinical form of leishmaniasis, being fatal if untreated. In search of a more effective treatment for VL, one of the main strategies is the development and screening of new antileishmanial compounds. Here, we reported the synthesis of seven new acetyl functionalized 1,2,3-triazolium salts, together with four 1,2,3-triazole precursors, and investigated their effect against different strains of L. infantum from dogs and humans. The 1,2,3-triazolium salts exhibited better activity than the 1,2,3-triazole derivatives with IC range from 0.12 to 8.66 μM and, among them, compound 5 showed significant activity against promastigotes (IC from 4.55 to 5.28 μM) and intracellular amastigotes (IC from 5.36 to 7.92 μM), with the best selective index (SI ~ 6-9) and reduced toxicity. Our findings, using biochemical and ultrastructural approaches, demonstrated that compound 5 targets the mitochondrion of L. infantum promastigotes, leading to the formation of reactive oxygen species (ROS), increase of the mitochondrial membrane potential, and mitochondrial alteration. Moreover, quantitative transmission electron microscopy (TEM) revealed that compound 5 induces the reduction of promastigote size and cytoplasmic vacuolization. Interestingly, the effect of compound 5 was not associated with apoptosis or necrosis of the parasites but, instead, seems to be mediated through a pathway involving autophagy, with a clear detection of autophagic vacuoles in the cytoplasm by using both a fluorescent marker and TEM. As for the in vivo studies, compound 5 showed activity in a mouse model of VL at 20 mg/kg, reducing the parasite load in both spleen and liver (59.80% and 26.88%, respectively). Finally, this compound did not induce hepatoxicity or nephrotoxicity and was able to normalize the altered biochemical parameters in the infected mice. Thus, our findings support the use of 1,2,3-triazolium salts as potential agents against visceral leishmaniasis.
内脏利什曼病（VL）是利什曼病中最严重的临床形式，如果不治疗则具有致命性。为了寻找更有效的 VL 治疗方法，主要策略之一是开发和筛选新的抗利什曼化合物。在这里，我们报告了七种新的乙酰基功能化 1,2,3-三唑鎓盐的合成，以及四种 1,2,3-三唑前体，并研究了它们对来自狗和人的不同株利什曼原虫的作用。与 1,2,3-三唑衍生物相比，1,2,3-三唑鎓盐的活性更好，IC 范围为 0.12 至 8.66 μM，其中化合物 5 对前鞭毛体（IC 为 4.55 至 5.28 μM）和内阿米巴（IC 为 5.36 至 7.92 μM）表现出显著的活性，最佳选择性指数（SI~6-9）和降低的毒性。使用生化和超微结构方法的研究结果表明，化合物 5 靶向利什曼原虫前鞭毛体的线粒体，导致活性氧（ROS）的形成、线粒体膜电位的增加和线粒体的改变。此外，定量透射电子显微镜（TEM）显示，化合物 5 诱导前鞭毛体大小减小和细胞质空泡化。有趣的是，化合物 5 的作用与寄生虫的凋亡或坏死无关，而是似乎通过涉及自噬的途径介导，通过使用荧光标记物和 TEM 在细胞质中清楚地检测到自噬空泡。对于体内研究，化合物 5 在 20 mg/kg 的 VL 小鼠模型中表现出活性，分别减少脾脏和肝脏中的寄生虫负荷（分别为 59.80%和 26.88%）。最后，该化合物不会引起肝毒性或肾毒性，并能够使感染小鼠的生化参数恢复正常。因此，我们的研究结果支持使用 1,2,3-三唑鎓盐作为治疗内脏利什曼病的潜在药物。
