Pathogenic and opportunistic free-living amoebae such as Acanthamoeba spp. can cause keratitis (Acanthamoeba keratitis [AK]), which may ultimately lead to permanent visual impairment or blindness. Acanthamoeba can also cause rare but usually fatal granulomatous amoebic encephalitis (GAE). Current therapeutic options for AK require a lengthy treatment with nonspecific drugs that are often associated with adverse effects. Recent developments in the field led us to target cAMP pathways, specifically phosphodiesterase. Guided by computational tools, we targeted the Acanthamoeba phosphodiesterase RegA. Computational studies led to the construction and validation of a homology model followed by a virtual screening protocol guided by induced-fit docking and chemical scaffold analysis using our medicinal and biological chemistry (MBC) chemical library. Subsequently, 18 virtual screening hits were prioritized for further testing in vitro against Acanthamoeba castellanii, identifying amoebicidal hits containing piperidine and urea imidazole cores. Promising activities were confirmed in the resistant cyst form of the amoeba and in additional clinical Acanthamoeba strains, increasing their therapeutic potential. Mechanism-of-action studies revealed that these compounds produce apoptosis through reactive oxygen species (ROS)-mediated mitochondrial damage. These chemical families show promise for further optimization to produce effective antiacanthamoebal drugs.

中文翻译：

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结合计算和实验方法发现杀菌剂化合物

致病性和机会性自由活动变形虫，如棘形棘阿奇藻。会导致角膜炎（棘阿米巴角膜炎[AK]），最终可能导致永久性视力障碍或失明。棘阿米巴还可引起罕见但通常致命的肉芽肿性阿米巴性脑炎（GAE）。当前AK的治疗选择需要用通常与不良反应有关的非特异性药物进行长期治疗。该领域的最新发展使我们靶向cAMP途径，特别是磷酸二酯酶。在计算工具的指导下，我们针对棘阿米巴磷酸二酯酶RegA。计算研究导致了同源性模型的构建和验证，随后是虚拟筛选方案，该方案由使用我们的药物和生物化学（MBC）化学库进行的诱导拟合对接和化学支架分析指导。随后，确定了18个虚拟筛选命中的优先级，以便进一步在体外针对卡氏棘阿米巴进行测试，以鉴定含有哌啶和尿素咪唑核心的杀真菌命中。在变形虫的耐药性囊肿和其他临床棘阿米巴中证实了有希望的活性菌株，增加其治疗潜力。作用机理研究表明，这些化合物通过活性氧（ROS）介导的线粒体损伤而产生凋亡。这些化学家族显示出有望进一步优化以生产有效的抗ac虫药的前景。