Environment-like exposure of free-living stages of Haemonchus contortus to albendazole: the intra- and intergeneration stability of altered expression of UDP-glycosyl transferases and ABC-transporters

Anthelmintic drugs are widespread environmental contaminants, but the consequences of their presence in the environment are still poorly understood. It is known that contact of parasitic nematode Haemonchus contortus with traces of anthelmintic drug albendazole (ABZ) altered the expression and activity of several UDP-glycosyl transferases (UGTs) and P-glycoproteins (Pgps, belonging to ABC-transporters), key enzymes in endogenous metabolism as well as in the defence against xenobiotics, including anthelmintics. However, it is not known whether the changes in expression patterns will last during the life cycle and pass to the next generations. In the present study simulating the environmental-like exposure, free-living stages of H. contortus were exposed or unexposed to a sub-lethal dose of ABZ and its transformation products during L3 development. The L3 served for lambs´ infection and H. contortus adults obtaining. The excrements from infected lambs were used to cultivate the second generation of L3, which were again exposed or unexposed to ABZ and its transformation products during development. The expression pattern of UGTs and Pgps was analysed and compared in the first generation of L3, in the adults, and in the second generation of L3. The results showed that ABZ exposition during larvae development altered the expression of several ugt and pgp genes in L3 and adults. The intrageneration stability of ABZ-evoked changes was observed in the case of ugt24b1, ugt368a1, and pgp11 expression. Concerning intergeneration stability, four genes (ugt365a1, ugt26a2, ugt368b1, and pgp13) maintained the altered expression in the second generation. Interestingly, ABZ-induced changes in the expression of some genes became apparent only in the second generation of L3. Taking together, contact of free-living stages of H. contortus with traces of ABZ and its metabolites in the environment evokes changes in the expression of certain UGTs and Pgps, with some of these changes being intra- and inter-generation stable.驱虫药是一类广泛分布的环境污染物，但其在环境中存留所带来的效应仍未得到充分解析。已知寄生性线虫捻转血矛线虫（Haemonchus contortus）接触微量驱虫药阿苯达唑（albendazole, ABZ）后，体内多种UDP-糖基转移酶（UGTs）以及P-糖蛋白（Pgps，属于ABC转运体家族）的表达与活性发生改变——这两类分子是内源代谢以及抵御包括驱虫药在内的外源性物质侵害的关键酶类。然而目前尚不明确，这类表达模式的改变是否会在其生命周期中持续存在，且能否传递至下一代。本研究模拟环境中的实际暴露场景，在三期幼虫（L3）的发育阶段，将捻转血矛线虫的自由生活阶段分别暴露于亚致死剂量的ABZ及其代谢产物，或不进行此类暴露。将经上述处理的L3感染羔羊，以获取成虫阶段的捻转血矛线虫。收集感染羔羊的粪便，用于培养第二代L3，同样在其发育阶段分别暴露或不暴露于ABZ及其代谢产物。随后对第一代L3、成虫以及第二代L3中的UGTs与Pgps的表达模式进行分析与比较。研究结果显示，幼虫发育阶段的ABZ暴露可改变L3与成虫体内多个ugt及pgp基因的表达。针对ugt24b1、ugt368a1及pgp11的表达，观察到ABZ诱导的改变具备世代内稳定性。关于跨世代稳定性，共有4个基因（ugt365a1、ugt26a2、ugt368b1及pgp13）在第二代L3中仍维持了表达改变的状态。值得注意的是，部分基因的ABZ诱导表达改变仅在第二代L3中才显现。综上，捻转血矛线虫的自由生活阶段接触环境中微量的ABZ及其代谢产物，会诱导其体内特定UGTs与Pgps的表达发生改变，其中部分改变兼具世代内与跨世代的稳定性。