Adeyemi Oluyomi Stephen, Johnson Titilayo, Maduakolam-Aniobi Tobiloba, Kato Kentaro
Medicinal Biochemistry and Toxicology Laboratory, Department of Biochemistry, Bowen University, Iwo, 232101, Osun State, Nigeria; Laboratory of Sustainable Animal Environment Systems, Graduate School of Agricultural Sciences, Tohoku University, Japan.
Department of Biochemistry, University of Jos, Jos, Plateau State, Nigeria.
Comput Biol Med. 2024 Dec;183:109236. doi: 10.1016/j.compbiomed.2024.109236. Epub 2024 Oct 7.
Toxoplasmosis is a widespread parasitic disease, caused by Toxoplasma gondii, that affects nearly one-third of the human population. The lack of effective treatments drives the demand for novel anti-toxoplasmosis therapeutic options. In the present study, we used computational approaches and experimental validation to identify therapeutic inhibitors of toxoplasmosis. Initially, using the structure of the co-crystallized ligand of T. gondii calcium-dependent protein kinase 1 (TgCDPK1), we retrieved 3000 compounds from the database of COCONUT (COlleCtion of Open Natural ProdUcTs). These compounds were docked against the crystal structure of TgCDPK1 on the Glide Ligand Docking panel of Maestro 12.5 (Schrödinger Suite 2020-3). Based on the docking scores, we assessed promising molecules for toxicity potential on the ProTox-II online server, while the ADME profiling was done on the SwissADME server. Following the computational studies, we selected nine promising compounds for experimental validation against T. gondii in vitro. Of the compounds, C4, C5, C6, and C8 exhibited dose-dependent anti-T. gondii action with EC values ranging from 3.3 to 120.2 μg/mL. Host toxicity profiling revealed differential cytotoxic action with a selectivity index (SI) of <1 for the compounds except C5, which had an SI of 1.8. To validate our screening assay, we used sulfadiazine, a standard drug for toxoplasmosis and showed that it inhibited parasite growth. Further experiments showed that C5, an imidazole-based natural compound, has strong but reversible anti-parasitic action that peaks within the first 8 h. In addition, C5 exhibited similar toxic tendencies towards T. gondii within (intracellular) and outside (extracellular) the host, suggesting it likely has a parasite target(s). C5 showed no effect on host invasion but strongly impeded parasite replication and growth, thereby affecting the T. gondii lytic cycle. Furthermore, C5 treatment raised the reactive oxygen species level, but this may be a secondary effect because augmentation with Trolox antioxidant failed to block C5 anti-T. gondii action. In addition, molecular dynamics simulations of C5 and TgCDPK1 complex revealed relative stability within 100 ns run time. Collectively, our findings support the potential of imidazole-based compounds as novel, alternative anti-parasitic agents.
弓形虫病是一种广泛传播的寄生虫病，由刚地弓形虫引起，影响着近三分之一的人类人口。缺乏有效的治疗方法推动了对新型抗弓形虫病治疗方案的需求。在本研究中，我们使用计算方法和实验验证来鉴定弓形虫病的治疗抑制剂。最初，利用刚地弓形虫钙依赖性蛋白激酶1（TgCDPK1）共结晶配体的结构，我们从COCONUT（开放天然产物集合）数据库中检索了3000种化合物。这些化合物在Maestro 12.5（Schrödinger Suite 2020 - 3）的Glide配体对接面板上与TgCDPK1的晶体结构进行对接。基于对接分数，我们在ProTox-II在线服务器上评估有前景分子的毒性潜力，同时在SwissADME服务器上进行药物代谢动力学性质分析。经过计算研究后，我们选择了九种有前景的化合物进行体外抗刚地弓形虫的实验验证。在这些化合物中，C4、C5、C6和C8表现出剂量依赖性的抗刚地弓形虫作用，其半数有效浓度（EC）值范围为3.3至120.2μg/mL。宿主毒性分析显示出不同的细胞毒性作用，除C5的选择性指数（SI）为1.8外，其他化合物的选择性指数均<1。为了验证我们的筛选试验，我们使用了弓形虫病的标准药物磺胺嘧啶，并证明它能抑制寄生虫生长。进一步的实验表明，C5是一种基于咪唑的天然化合物，具有强烈但可逆的抗寄生虫作用，在最初8小时内达到峰值。此外，C5对宿主内（细胞内）外（细胞外）的刚地弓形虫表现出相似的毒性倾向，表明它可能有寄生虫靶点。C5对宿主入侵没有影响，但强烈阻碍寄生虫的复制和生长，从而影响刚地弓形虫的裂解周期。此外，C5处理提高了活性氧水平，但这可能是一种次要效应，因为用生育三烯酚抗氧化剂增强并没有阻断C5的抗刚地弓形虫作用。此外，C5与TgCDPK1复合物的分子动力学模拟显示在100纳秒的运行时间内具有相对稳定性。总的来说，我们的研究结果支持基于咪唑的化合物作为新型替代抗寄生虫药物的潜力。
