Laboratório de Modelagem Molecular e Planejamento de Fármacos, Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Avenida Antonio Carlos 6627, Belo Horizonte, MG, 31270-901, Brazil; CAPES Foundation, Ministry of Education of Brazil, Brasília, DF, Brazil.
Laboratório de Modelagem Molecular e Planejamento de Fármacos, Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Avenida Antonio Carlos 6627, Belo Horizonte, MG, 31270-901, Brazil.
Eur J Med Chem. 2019 Oct 1;179:765-778. doi: 10.1016/j.ejmech.2019.06.062. Epub 2019 Jun 22.
Chagas disease, Human African Trypanosomiasis, and schistosomiasis are neglected parasitic diseases for which new treatments are urgently needed. To identify new chemical leads, we screened the 400 compounds of the Open Access Malaria Box against the cysteine proteases, cruzain (Trypanosoma cruzi), rhodesain (Trypanosoma brucei) and SmCB1 (Schistosoma mansoni), which are therapeutic targets for these diseases. Whereas just three hits were observed for SmCB1, 70 compounds inhibited cruzain or rhodesain by at least 50% at 5 μM. Among those, 15 commercially available compounds were selected for confirmatory assays, given their potency, time-dependent inhibition profile and reported activity against parasites. Additional assays led to the confirmation of four novel classes of cruzain and rhodesain inhibitors, with potency in the low-to mid-micromolar range against enzymes and T. cruzi. Assays against mammalian cathepsins S and B revealed inhibitor selectivity for parasitic proteases. For the two competitive inhibitors identified (compounds 7 and 12), their binding mode was predicted by docking, providing a basis for structure-based optimization efforts. Compound 12 also acted directly against the trypomastigote and the intracellular amastigote forms of T. cruzi at 3 μM. Therefore, through a combination of experimental and computational approaches, we report promising hits for optimization in the development of new trypanocidal drugs.
恰加斯病、非洲人类锥虫病和血吸虫病是被忽视的寄生虫病，急需新的治疗方法。为了寻找新的化学先导物，我们对开放获取的疟疾药物库中的 400 种化合物进行了筛选，以检测半胱氨酸蛋白酶（克氏锥虫、布氏锥虫）和 SmCB1（曼氏血吸虫），这些酶是这些疾病的治疗靶点。虽然只有三种化合物对 SmCB1 有作用，但有 70 种化合物在 5μM 时对 cruzain 或 rhodesain 的抑制率至少达到了 50%。其中，15 种商业可得的化合物因其效力、时间依赖性抑制谱和对寄生虫的报道活性而被选中进行确证性测定。其他测定方法进一步确认了 cruzain 和 rhodesain 的四个新的抑制剂类别，对酶和 T. cruzi 的活性在低至中微摩尔范围内。对哺乳动物组织蛋白酶 S 和 B 的测定显示抑制剂对寄生虫蛋白酶具有选择性。对于鉴定出的两种竞争性抑制剂（化合物 7 和 12），通过对接预测了它们的结合模式，为基于结构的优化工作提供了基础。化合物 12 还在 3μM 时直接作用于 T. cruzi 的锥虫体和内阿米巴体形式。因此，通过实验和计算方法的结合，我们报告了有希望的化合物作为优化的先导物，用于开发新的杀锥虫药物。
