PDF(Pubmed)
Abstract：
Aldo-keto reductases (AKRs), a superfamily of NADP(H)-dependent oxidoreductases, catalyze the oxidoreduction of a wide variety of eobiotic and xenobiotic aldehydes and ketones. In mammals, AKRs play essential roles in hormone and xenobiotic metabolism, oxidative stress, and drug resistance, but little is known about these enzymes in the parasitic nematode Haemonchus contortus. In the present study, 22 AKR genes existing in the H. contortus genome were investigated and a phylogenetic analysis with comparison to AKRs in Caenorhabditis elegans, sheep and humans was conducted. The constitutive transcription levels of all AKRs were measured in eggs, larvae, and adults of H. contortus, and their expression was compared in a drug-sensitive strain (ISE) and a benzimidazole-resistant strain (IRE) previously derived from the sensitive strain by imposing benzimidazole selection pressure. In addition, the inducibility of AKRs by exposure of H. contortus adults to benzimidazole anthelmintic flubendazole in vitro was tested. Phylogenetic analysis demonstrated that the majority of AKR genes in H. contortus lack orthologues in the sheep genome, which is a favorable finding for considering AKRs as potential drug targets. Large differences in the expression levels of individual AKRs were observed, with AKR1, AKR3, AKR8, and AKR10 being the most highly expressed at most developmental stages. Significant changes in the expression of AKRs during the life cycle and pronounced sex differences were found. Comparing the IRE and ISE strains, three AKRs were upregulated, and seven AKRs were downregulated in adults. In addition, the expression of three AKRs was induced by flubendazole exposure in adults of the ISE strain. Based on these results, AKR1, AKR2, AKR3, AKR5, AKR10 and AKR19 in particular merit further investigation and functional characterization with respect to their potential involvement in drug biotransformation and anthelmintic resistance in H. contortus.
摘要：
Aldo-keto还原酶（AKRs），NADP（H）依赖性氧化还原酶的超家族，催化各种生物和异生醛和酮的氧化还原。在哺乳动物中,AKRs在激素和外源性生物代谢中发挥重要作用，氧化应激，和抗药性，但是对寄生线虫中的这些酶知之甚少。在本研究中,研究了H.contortus基因组中存在的22个AKR基因，并与秀丽隐杆线虫中的AKR进行了系统发育分析，进行了绵羊和人类。在卵中测量所有AKRs的组成型转录水平，幼虫,和扭曲的成年人，并通过施加苯并咪唑选择压力在先前源自敏感菌株的药物敏感菌株（ISE）和苯并咪唑抗性菌株（IRE）中比较了它们的表达。此外,在体外测试了H.contortus成年人暴露于苯并咪唑驱虫药氟苯达唑对AKRs的诱导性。系统发育分析表明，扭曲H.的大多数AKR基因在绵羊基因组中缺乏直系同源物，这是考虑AKRs作为潜在药物靶标的有利发现。观察到个体AKRs的表达水平存在很大差异，AKR1，AKR3，AKR8和AKR10在大多数发育阶段表达最高。发现生命周期中AKRs表达的显着变化和明显的性别差异。比较IRE和ISE菌株，三个AKR上调，7个AKRs在成人中下调。此外,在ISE菌株的成虫中，氟苯达唑暴露诱导了三种AKRs的表达。基于这些结果,AKR1，AKR2，AKR3，AKR5，AKR10和AKR19尤其值得进一步研究和功能表征，因为它们可能参与H.contortus的药物生物转化和驱虫抗性。
