In vitro anti-trypanosomal effect of ivermectin on Trypanosoma evansi by targeting multiple metabolic pathways

Abstract

High cytotoxicity and increasing resistance reports of existing chemotherapeutic agents against T. evansi have raised the demand for novel, potent, and high therapeutic index molecules for the treatment of surra in animals. In this regard, repurposing approach of drug discovery has provided an opportunity to explore the therapeutic potential of existing drugs against new organism. With this objective, the macrocyclic lactone representative, ivermectin, has been investigated for the efficacy against T. evansi in the axenic culture medium. To elucidate the potential target of ivermectin in T. evansi , mRNA expression profile of 13 important drug target genes has been studied at 12, 24, and 48 h interval. In the in vitro growth inhibition assay, ivermectin inhibited T. evansi growth and multiplication significantly ( p < 0.001) with IC 50 values of 13.82 μM, indicating potent trypanocidal activity. Cytotoxicity assays on equine peripheral blood mononuclear cells (PBMCs) and Vero cell line showed that ivermectin affected the viability of cells with a half-maximal cytotoxic concentration (CC 50 ) at 17.48 and 22.05 μM, respectively. Data generated showed there was significant down-regulation of hexokinase ( p < 0.001), ESAG8 ( p < 0.001), aurora kinase ( p < 0.001), casein kinase 1 ( p < 0.001), topoisomerase II ( p < 0.001), calcium ATPase 1 ( p < 0.001), ribonucleotide reductase I ( p < 0.05), and ornithine decarboxylase ( p < 0.01). The mRNA expression of oligopeptidase B remains refractory to the exposure of the ivermectin. The arginine kinase 1 and ribonucleotide reductase II showed up-regulation on treatment with ivermectin. The ivermectin was found to affect glycolytic pathways, ATP-dependent calcium ATPase, cellular kinases, and other pathway involved in proliferation and maintenance of internal homeostasis of T. evansi. These data imply that intervention with alternate strategies like nano-formulation, nano-carriers, and nano-delivery or identification of ivermectin homologs with low cytotoxicity and high bioavailability can be explored in the future as an alternate treatment for surra in animals. Graphical abstract

Avaliação in vitro da citotoxicidade do extrato de Croton lechleri Müll. Arg. (Euphorbiaceae) e sua equivalência com compostos quinoléicos e avermectina

“…Esse estudo também demonstrou que ao observar o CC₅₀ destes compostos em diferentes tempos de exposição como 24, 48 e 72h, a CQ acabou apresentando uma maior viabilidade celular em 72h quando comparada a 48h, e a HCQ apresentou uma queda consideravelmente baixa da viabilidade celular no tempo de 72h quando comparada ao tempo de 48h. Essa alteração pode ter ocorrido devido ao metabolismo da droga na célula ou à estabilidade da mesma.Um estudo publicado porGupta et al (2022), sustenta o resultado que a Ivermectina é tóxica para as células VERO, neste trabalho as células foram expostas nas concentrações 13, 26, 65, 130 e 260 µM, onde a citotoxicidade foi maior de 30%, obtendo um CC₅₀ de 17,48 µM. Mesmo este composto apresentando-se altamente citotóxico, para as células neste ensaio, a…”