Abstract：
Toxoplasma gondii and Neospora caninum are major worldwide morbidity-causing pathogens. Bumped kinase inhibitors (BKIs) are a compound class that has been optimized to target the apicomplexan calcium-dependent protein kinase 1 (CDPK1) - and several members of this class have proven to be safe and highly active in vitro and in vivo. BKI-1708 is based on a 5-aminopyrazole-4-carboxamide scaffold, and exhibited in vitro IC50 values of 120 nM for T. gondii and 480 nM for N. caninum β-galactosidase expressing strains, and did not affect human foreskin fibroblast (HFF) viability at concentrations up to 25 μM. Electron microscopy established that exposure of tachyzoite-infected fibroblasts to 2.5 μM BKI-1708 in vitro induced the formation of multinucleated schizont-like complexes (MNCs), characterized by continued nuclear division and harboring newly formed intracellular zoites that lack the outer plasma membrane. These zoites were unable to finalize cytokinesis to form infective tachyzoites. BKI-1708 did not affect zebrafish (Danio rerio) embryo development during the first 96 h following egg hatching at concentrations up to 2 μM. Treatments of mice with BKI-1708 at 20 mg/kg/day during five consecutive days resulted in drug plasma levels ranging from 0.14 to 4.95 μM. In vivo efficacy of BKI-1708 was evaluated by oral application of 20 mg/kg/day from day 9-13 of pregnancy in mice experimentally infected with N. caninum (NcSpain-7) tachyzoites or T. gondii (TgShSp1) oocysts. This resulted in significantly decreased cerebral parasite loads and reduced vertical transmission in both models without drug-induced pregnancy interference.
摘要：
弓形虫和犬新孢子虫是世界范围内主要的致病病原体。碰撞激酶抑制剂（BKIs）是一类化合物，已被优化为靶向顶复钙依赖性蛋白激酶1（CDPK1）-并且该类的几个成员已被证明在体外和体内是安全且具有高活性的。BKI-1708基于5-氨基吡唑-4-甲酰胺支架，并在体外表现出120nM的弓形虫和480nM的犬奈米β-半乳糖苷酶表达菌株的IC50值，并且在高达25μM的浓度下不影响人包皮成纤维细胞(HFF)活力。电子显微镜确定，速殖子感染的成纤维细胞在体外暴露于2.5μMBKI-1708可诱导多核裂殖样复合物（MNC）的形成，以持续的核分裂为特征，并带有新形成的缺乏外质膜的胞内动物。这些动物无法完成胞质分裂以形成感染性速殖子。BKI-1708在卵孵化后的第一个96小时内，浓度高达2μM，不会影响斑马鱼（Daniorerio）的胚胎发育。在连续五天期间用20mg/kg/天的BKI-1708处理小鼠导致药物血浆水平在0.14至4.95μM的范围内。BKI-1708的体内功效通过从怀孕的第9-13天口服施用20mg/kg/天在实验感染犬奈瑟氏菌(NcSpain-7)速殖子或弓形虫(TgShSp1)卵囊的小鼠中评价。在没有药物诱导的妊娠干扰的情况下，这两种模型的脑寄生虫负荷显着降低，垂直传播减少。
