Chagas disease, also known as American trypanosomiasis, is a neglected tropical disease caused by the protozoa Trypanosoma cruzi, affecting nearly 7 million people only in the Americas. Polyamines are essential compounds for parasite growth, survival, and differentiation. However, because trypanosomatids are auxotrophic for polyamines, they must be obtained from the host by specific transporters. In this investigation, an ensemble of QSAR classifiers able to identify polyamine analogs with trypanocidal activity was developed. Then, a multi-template homology model of the dimeric polyamine transporter of T. cruzi, TcPAT12, was created with Rosetta, and then refined by enhanced sampling molecular dynamics simulations. Using representative snapshots extracted from the trajectory, a docking model able to discriminate between active and inactive compounds was developed and validated. Both models were applied in a parallel virtual screening campaign to repurpose known drugs as anti-trypanosomal compounds inhibiting polyamine transport in T. cruzi. Montelukast, Quinestrol, Danazol, and Dutasteride were selected for in vitro testing, and all of them inhibited putrescine uptake in biochemical assays, confirming the predictive ability of the computational models. Furthermore, all the confirmed hits proved to inhibit epimastigote proliferation, and Quinestrol and Danazol were able to inhibit, in the low micromolar range, the viability of trypomastigotes and the intracellular growth of amastigotes.

Graphical abstract

中文翻译：

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一种结合配体和基于靶点的虚拟筛选策略，将药物重新用作具有杀锥虫活性的腐胺摄取抑制剂

恰加斯病，也称为美洲锥虫病，是一种被忽视的热带疾病，由原生动物克氏锥虫引起，仅在美洲就影响了近 700 万人。多胺是寄生虫生长、存活和分化的必需化合物。然而，由于锥体虫对多胺是营养缺陷型的，因此它们必须通过特定的转运蛋白从宿主获得。在这项调查中，开发了一组能够识别具有杀锥虫活性的多胺类似物的 QSAR 分类器。然后， T. cruzi, Tc的二聚多胺转运蛋白的多模板同源模型PAT12 是使用 Rosetta 创建的，然后通过增强的采样分子动力学模拟进行了改进。使用从轨迹中提取的代表性快照，开发并验证了能够区分活性和非活性化合物的对接模型。这两种模型都应用于平行的虚拟筛选活动，以将已知药物重新用作抑制克氏锥虫多胺转运的抗锥虫化合物. Montelukast、Quinestrol、Danazol 和 Dutasteride 被选作体外测试，它们在生化分析中都抑制了腐胺的摄取，证实了计算模型的预测能力。此外，所有已确认的命中均证明可抑制 epimastigotes 增殖，Quinestrol 和 Danazol 能够在低微摩尔范围内抑制 trypomastigotes 的活力和无鞭毛体的细胞内生长。

图形概要