Department of Pharmacy, The First Affiliated Hospital, Xinjiang Medical University, Urumqi, Xinjiang, PR China; Jiangsu Province Key Laboratory for Molecular and Medical Biotechnology, College of Life Science Nanjing Normal University, Nanjing, Jiangsu, PR China.
Department of Pharmacy, The First Affiliated Hospital, Xinjiang Medical University, Urumqi, Xinjiang, PR China; College of Pharmacy, Xinjiang Medical University, Urumqi, Xinjiang, PR China.
Exp Parasitol. 2021 Jul-Aug;226-227:108121. doi: 10.1016/j.exppara.2021.108121. Epub 2021 Jun 9.
Cystic echinococcosis (CE), a parasitic larval cystic stage of a small taeniid-type tapeworm (Echinococcus granulosus), causes illness in intermediate hosts and has become a threat to global public health. Currently, chemical compounds recommended by the WHO targeting CE are albendazole and mebendazole, however, none of them shows enhanced efficacy. Novel molecular compounds are urgently required to treat this disease. Our group uncover a drug, termed harmine (HM), that may be capable of treating CE. In this study, we aim to evaluate the anti-parasitic efficacy and the mechanism of DNA damage of HM against E. granulosus. In vitro, the results indicated that, within two and three days of treatment, ABZ killed 30.4% and 35.3% of protoscoleces, whereas HM killed 52.7% and 100% of protoscoleces, respectively. Furthermore, the presence of abnormalities in the internal structure of protoscoleces was examined by ultrastructural images of TEM, and the result showed that there were scattered nucleoli and heterochromatin margination phenomenon by HM treatment. DNA damage of protoscoleces was examined by using the comet assay, and results showed the DNA of protoscoleces was damaged. Moreover, EgATM, EgP53, EgTopo2a and EgRad54 genes were used to support the DNA damage by HM treatment, and results showed that all four genes were upregulated expression. In further, the result of HM treatment was tested by using designed siRNA to inhibit the expression of EgTopo2a and EgRad54. The results demonstrated that the viability was 88.75 ± 2.11% after suppressing the expression of EgTopo2a, which was significantly higher than that for HM alone group (P < 0.01). The viability was 10.11 ± 2.60% after transfected with EgRad54 siRNA, which was significantly lower compared with the HM alone group (P < 0.01). Based on our preliminary data, HM demonstrated significant parasiticidal activity against E. granulosus in vitro without obvious toxicity towards its host cells, suggesting that HM can be a potential anti-echinococcosis drug. HM was found to induce DNA damages of CE by activating the EgATM-EgP53-EgTopo2a signaling pathway. We therefore surmise that DNA damage response may be one of the mechanisms of HM against the parasite.
囊性包虫病 (CE) 是一种小型带绦虫 (细粒棘球绦虫) 的幼虫囊性阶段寄生虫，会导致中间宿主患病，已成为全球公共卫生的威胁。目前，世界卫生组织推荐的针对 CE 的化学化合物是阿苯达唑和甲苯达唑，但它们都没有显示出增强的疗效。迫切需要新型分子化合物来治疗这种疾病。我们的研究小组发现了一种名为 harmine (HM) 的药物，它可能具有治疗 CE 的能力。在这项研究中，我们旨在评估 HM 对 E. granulosus 的抗寄生虫功效和 DNA 损伤机制。在体外，结果表明，ABZ 在治疗两天和三天后分别杀死了 30.4%和 35.3%的原头蚴，而 HM 则分别杀死了 52.7%和 100%的原头蚴。此外，通过 TEM 的超微结构图像检查了原头蚴内部结构异常，结果表明 HM 处理后有散在的核仁与异染色质边缘化现象。通过彗星分析检查了原头蚴的 DNA 损伤，结果显示原头蚴的 DNA 受到了损伤。此外，使用 EgATM、EgP53、EgTopo2a 和 EgRad54 基因来支持 HM 处理引起的 DNA 损伤，结果表明这四个基因的表达均上调。进一步用设计的 siRNA 抑制 EgTopo2a 和 EgRad54 的表达来测试 HM 的治疗效果。结果表明，抑制 EgTopo2a 表达后，活力为 88.75±2.11%，明显高于单独使用 HM 的组（P<0.01）。转染 EgRad54 siRNA 后活力为 10.11±2.60%，明显低于单独使用 HM 的组（P<0.01）。根据我们的初步数据，HM 在体外对 E. granulosus 表现出显著的杀寄生虫活性，而对其宿主细胞没有明显的毒性，表明 HM 可能是一种潜在的抗包虫病药物。发现 HM 通过激活 EgATM-EgP53-EgTopo2a 信号通路诱导 CE 的 DNA 损伤。因此，我们推测 DNA 损伤反应可能是 HM 对抗寄生虫的机制之一。
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