Sánchez Di Maggio Lucía, Tirloni Lucas, Uhl Marcelle, Carmona Carlos, Logullo Carlos, Mulenga Albert, da Silva Vaz Itabajara, Berasain Patrícia
Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Unidad de Biología Parasitaria, Facultad de Ciencias, Universidad de la República Oriental del Uruguay, Montevideo, Uruguay.
Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, USA.
Int J Parasitol. 2020 Oct;50(12):931-943. doi: 10.1016/j.ijpara.2020.05.010. Epub 2020 Jul 12.
Protease inhibitors play crucial roles in parasite development and survival, modulating the immune responses of their vertebrate hosts. Members of the serpin family are irreversible inhibitors of serine proteases and regulate systems related to defence against parasites. Limited information is currently available on protease inhibitors from the liver fluke Fasciola hepatica. In this study, we characterised four serpins from F. hepatica (FhS-1-FhS-4). Biochemical characterisation revealed that recombinant FhS-2 (rFhS) inhibits the activity of human neutrophil cathepsin G, while rFhS-4 inhibits the activity of bovine pancreatic chymotrypsin and cathepsin G. Consistent with inhibitor function profiling data, rFhS-4 inhibited cathepsin G-activated platelet aggregation in a dose-responsive manner.Similar to other serpins, rFhS2 and rFhS-4 bind to heparin with high affinity. Tissue localisation demonstrated that these serpins have different spatial distributions. FhS-2 is localised in the ovary, while FhS-4 was found in gut cells. Both of them co-localised in the spines within the tegument. These findings provide the basis for study of functional roles of these proteins as part of an immune evasion mechanism in the adult fluke, and in protection of eggs to ensure parasite life cycle continuity. Further understanding of serpins from the liver fluke may lead to the discovery of novel anti-parasitic interventions.
蛋白酶抑制剂在寄生虫的发育和生存中发挥着关键作用，调节其脊椎动物宿主的免疫反应。丝氨酸蛋白酶抑制剂（serpin）家族成员是丝氨酸蛋白酶的不可逆抑制剂，可调节与抵御寄生虫相关的系统。目前关于肝片吸虫（Fasciola hepatica）蛋白酶抑制剂的信息有限。在本研究中，我们对肝片吸虫的四种丝氨酸蛋白酶抑制剂（FhS-1 - FhS-4）进行了表征。生化特性表明，重组FhS-2（rFhS）可抑制人中性粒细胞组织蛋白酶G的活性，而rFhS-4可抑制牛胰凝乳蛋白酶和组织蛋白酶G的活性。与抑制剂功能分析数据一致，rFhS-4以剂量反应方式抑制组织蛋白酶G激活的血小板聚集。与其他丝氨酸蛋白酶抑制剂类似，rFhS2和rFhS-4与肝素具有高亲和力。组织定位表明这些丝氨酸蛋白酶抑制剂具有不同的空间分布。FhS-2定位于卵巢，而FhS-4存在于肠道细胞中。它们都共定位于皮层内的棘中。这些发现为研究这些蛋白质作为成虫免疫逃避机制的一部分以及保护虫卵以确保寄生虫生命周期连续性的功能作用提供了基础。对肝片吸虫丝氨酸蛋白酶抑制剂的进一步了解可能会导致发现新的抗寄生虫干预措施。
