Padalino Gilda, Chalmers Iain W, Brancale Andrea, Hoffmann Karl F
Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, Wales, SY23 3DA, UK.
School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, Wales, CF10 3NB, UK.
Wellcome Open Res. 2020 Nov 13;5:169. doi: 10.12688/wellcomeopenres.16069.2. eCollection 2020.
Schistosomiasis, caused by infection with blood fluke schistosomes, is a neglected tropical disease of considerable importance in resource-poor communities throughout the developing world. In the absence of an immunoprophylactic vaccine and due to over-reliance on a single chemotherapy (praziquantel), schistosomiasis control is at risk should drug insensitive schistosomes develop. In this context, application of virtual screening on validated schistosome targets has proven successful in the identification of novel small molecules with anti-schistosomal activity. Focusing on the histone methylation machinery, we herein have used RNA interference (RNAi), ELISA-mediated detection of H3K4 methylation, homology modelling and virtual screening to identify a small collection of small molecules for anti-schistosomal testing. A combination of low to high-throughput whole organism assays were subsequently used to assess these compounds' activities on miracidia to sporocyst transformation, schistosomula phenotype/motility metrics and adult worm motility/oviposition readouts. RNAi-mediated knockdown of (encoding a histone methyltransferase, HMT) in adult worms (~60%) reduced parasite motility and egg production. Moreover, docking of compounds into Smp_138030/SmMLL-1's homology model highlighted competitive substrate pocket inhibitors, some of which demonstrated significant activity on miracidia, schistosomula and adult worm lifecycle stages together with variable effects on HepG2 cells. Particularly, the effect of compounds containing a 6-(piperazin-1-yl)-1,3,5-triazine core on adult schistosomes recapitulated the results of the RNAi screens. The biological data and the structure-activity relationship presented in this study define the 6-(piperazin-1-yl)-1,3,5-triazine core as a promising starting point in ongoing efforts to develop new urgently needed schistosomicides.
血吸虫病是由感染血吸虫血吸虫引起的，是一种被忽视的热带疾病，在整个发展中世界的资源匮乏社区具有相当重要的意义。由于缺乏免疫预防性疫苗，且过度依赖单一化疗药物（吡喹酮），如果出现对药物不敏感的血吸虫，血吸虫病的控制将面临风险。在这种情况下，对经过验证的血吸虫靶点进行虚拟筛选已被证明在鉴定具有抗血吸虫活性的新型小分子方面是成功的。 我们专注于组蛋白甲基化机制，在此使用RNA干扰（RNAi）、ELISA介导的H3K4甲基化检测、同源建模和虚拟筛选来鉴定一小批用于抗血吸虫测试的小分子。随后使用从低到高通量的全生物体试验组合来评估这些化合物对毛蚴到孢蚴转化、童虫表型/运动指标以及成虫运动/产卵读数的活性。RNAi介导的成虫（约60%）中（编码一种组蛋白甲基转移酶，HMT）的敲低降低了寄生虫的运动性和产卵量。此外，将化合物对接至Smp_138030/SmMLL-1的同源模型中突出显示了竞争性底物口袋抑制剂，其中一些在毛蚴、童虫和成虫生命周期阶段表现出显著活性，同时对HepG2细胞有不同影响。特别是，含有6-（哌嗪-1-基）-1,3,5-三嗪核心的化合物对成虫血吸虫的作用概括了RNAi筛选的结果。本研究中呈现的生物学数据和构效关系将6-（哌嗪-1-基）-1,3,5-三嗪核心定义为正在进行的开发急需的新型抗血吸虫药物努力中的一个有前景的起点。
