Function and relevance of the P-glycoproteins for anthelmintic resistance in Parascaris univalens

寄生线虫对人类和动物的健康构成了相当大和广泛的威胁。蛔虫是一种特别致病的肠道寄生虫，通常会影响幼年动物。例如，小马驹和一周岁的幼崽可能会患上重病，甚至是致命的疾病。在过去的二三十年里，用于治疗这些寄生虫的驱虫剂已经失去了很大的效力。在缺乏新的驱虫药或疫苗的情况下，驱虫药耐药性正在日益威胁受影响动物物种的健康，在某些情况下，也威胁到人类的健康。在发展耐药性的前景中，动物和人类中的蛔虫。大环内酯(MLS)是最新的用于对抗马虫的活性物质，但它们在大约30年前就已经获得批准。特别是，马蛔虫，如单价副寄生虫，现在已经对世界各地的MLS产生了抗药性。鉴于这种情况，为了遏制抗药性种群的进一步传播，科学合理的方法至关重要，例如用于早期检测抗药性但也用于逆转抗药性。为此，我们一直在研究被称为P-糖蛋白(PGP)的跨膜泵的药物外流。在哺乳动物中通常只有一个或两个Pgp基因，而线虫基因组有很多，尤其是P.univalens有10个Pgp。以往的研究表明，在寄生和自由生活的线虫(如秀丽线虫)中，PgP都参与了MLS的外流。对于P.univalens，我们描述了所有Pgp基因的序列，首次收集了这些基因中大多数在不同组织中转录的有意义的数据，描述了与ML抗性相关的Pgp-11可能的基因多态，为Pgp诱导的MLS外流的显著组织特异性差异提供了证据，并通过体外靶向性研究描述了一种新的化学先导结构作为线虫Pgps的抑制剂。在这里申请的延续项目中，我们打算就线虫对不同ML和ML敏感性的药效学方面阐明最重要的Pgp在ML作用和耐药性中的作用。此外，我们的目的是在细胞水平上展示这些PgP在单价青霉中的表达，以便能够将在线虫中收集的关于PgP功能的数据与它们在目标生物体中的存在进行比较。此外，我们希望首次使用质谱分析来显示单价肺炎杆菌组织之间的MLS的梯度。最近对Pgp抑制剂铅结构的观察将成为专门阻止线虫而不是宿主Pgp的衍生结构的特征的基础。

Parasitic nematodes pose a considerable and widespread threat to human and animal health. Roundworms are a particularly pathogenic group of intestinal parasites that usually affect young animals. Horse foals and yearlings, for example, can become seriously or even fatally ill. The anthelmintics used to treat these parasites have lost much of their effectiveness over the past two to three decades. In the absence of new anthelmintic drugs or vaccines, anthelmintic resistance is increasingly threatening the health of the affected animal species and, in some cases, also of humans. In the foreground of the development of resistance are roundworms in animals and humans. The macrocyclic lactones (MLs) are the latest active substances used to combat horse worms, but they were already approved about 30 years ago. In particular, equine roundworms such as Parascaris univalens have now developed resistance to MLs worldwide. In order to counteract the further spread of resistant P. univalens populations in view of this situation, scientifically sound approaches, e.g. for the early detection of resistance but also for the reversion of resistance, are of crucial importance. To this end, we have been investigating drug efflux by transmembrane pumps called P-glycoproteins (Pgp). While in mammals there are usually only one or two Pgp genes, nematode genomes have many, P. univalens specifically ten, Pgps. Previous studies showed that Pgps are involved in the efflux of MLs in both parasitic and free-living nematodes (e.g. Caenorhabditis elegans). For P. univalens, we have described the sequences of all Pgp genes, collected first meaningful data on the transcription of the majority of these genes in different tissues, described putative gene polymorphisms for Pgp-11 associated with ML resistance, provided evidence for significant tissue-specific differences in Pgp-induced efflux of MLs, and described a new chemical lead structure as an inhibitor of nematode Pgps through targeted in vitro studies. In the continuation project applied for here, we intend to clarify the role of the most important Pgps in ML action and resistance with regard to the pharmacodynamics of different MLs and ML susceptibility in nematodes. In addition, it is our aim to show the expression of these Pgps in P. univalens at the cellular level in order to be able to compare the data collected in C. elegans on the function of the Pgps with their occurrence in the target organism. Furthermore, we want to use mass spectrometric analyses to show gradients of MLs between P. univalens tissues for the first time. The recent observations on a Pgp inhibitor lead structure will be the basis for characterisations of derivatised structures that specifically block nematodes but not host Pgps.