Abstract：
Xenobiotic biotransformation is an important modulator of anthelmintic drug potency and a potential mechanism of anthelmintic resistance. Both the free-living nematode Caenorhabditis elegans and the ruminant parasite Haemonchus contortus biotransform benzimidazole drugs by glucose conjugation, likely catalysed by UDP-glycosyltransferase (UGT) enzymes. To identify C. elegans genes involved in benzimidazole drug detoxification, we first used a comparative phylogenetic analysis of UGTs from humans, C. elegans and H. contortus, combined with available RNAseq datasets to identify which of the 63 C. elegans ugt genes are most likely to be involved in benzimidazole drug biotransformation. RNA interference knockdown of 15 prioritized C. elegans genes identified those that sensitized animals to the benzimidazole derivative albendazole (ABZ). Genetic mutations subsequently revealed that loss of ugt-9 and ugt-11 had the strongest effects. The \"ugt-9 cluster\" includes these genes, together with six other closely related ugts. A CRISPR-Cas-9 deletion that removed seven of the eight ugt-9 cluster genes had greater ABZ sensitivity than the single largest-effect mutation. Furthermore, a double mutant of ugt-22 (which is not a member of the ugt-9 cluster) with the ugt-9 cluster deletion further increased ABZ sensitivity. This additivity of mutant phenotypes suggest that ugt genes act in parallel, which could have several, not mutually exclusive, explanations. ugt mutations have different effects with different benzimidazole derivatives, suggesting that enzymes with different specificities could together more efficiently detoxify drugs. Expression patterns of ugt-9, ugt-11 and ugt-22 gfp reporters differ and so likely act in different tissues which may, at least in part, explain their additive effects on drug potency. Overexpression of ugt-9 alone was sufficient to confer partial ABZ resistance, indicating increasing total UGT activity protects animals. In summary, our results suggest that the multiple UGT enzymes have overlapping but not completely redundant functions in benzimidazole drug detoxification and may represent \"druggable\" targets to improve benzimidazole drug potency.
摘要：
异种生物转化是驱虫药物效力的重要调节剂，也是驱虫耐药的潜在机制。通过葡萄糖缀合，自由生活的线虫秀丽隐杆线虫和反刍动物寄生虫扭曲的生物转化苯并咪唑药物，可能由UDP-糖基转移酶（UGT）酶催化。为了鉴定参与苯并咪唑药物解毒的秀丽隐杆线虫基因，我们首先使用了人类UGTs的比较系统发育分析，C.线虫和H.扭曲，结合可用的RNAseq数据集来确定63个C.elegansugt基因中的哪一个最有可能参与苯并咪唑药物生物转化。15个优先的C.elegans基因的RNA干扰敲除鉴定了那些使动物对苯并咪唑衍生物阿苯达唑(ABZ)敏感的基因。遗传突变随后显示，ugt-9和ugt-11的丢失具有最强的影响。“ugt-9簇”包括这些基因，以及其他六个密切相关的ugts。去除8个ugt-9簇基因中的7个的CRISPR-Cas-9缺失比单个最大效应突变具有更大的ABZ敏感性。此外，具有ugt-9簇缺失的ugt-22（不是ugt-9簇的成员）的双突变体进一步提高了ABZ敏感性。突变表型的这种加性表明ugt基因平行作用，可能有几个，不是相互排斥的，解释。ugt突变对不同的苯并咪唑衍生物有不同的影响，表明具有不同特异性的酶可以一起更有效地解毒药物。ugt-9，ugt-11和ugt-22gfp报告基因的表达模式不同，因此可能在不同的组织中起作用，至少在某种程度上,解释它们对药物效力的累加效应。单独过表达ugt-9足以赋予部分ABZ抗性，表明增加的总UGT活性保护动物。总之,我们的结果表明,多种UGT酶在苯并咪唑药物解毒中具有重叠但并非完全冗余的功能,并且可能代表提高苯并咪唑药物效力的"可药用"靶标.
