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    Genetic variants and increased expression of Parascaris equorum P-glycoprotein-11 in populations with decreased ivermectin susceptibility (2013)

    Art
    Zeitschriftenartikel / wissenschaftlicher Beitrag
    Autoren
    Janssen, Jana (WE 13)
    Krücken, Jürgen (WE 13)
    Demeler, Janina (WE 13)
    Basiaga, Marta
    Kornaś, Sławomir
    von Samson-Himmelstjerna, Georg (WE 13)
    Quelle
    PLoS one; 8(4) — S. e61635
    ISSN: 1932-6203
    Sprache
    Englisch
    Verweise
    URL (Volltext): http://edocs.fu-berlin.de/docs/receive/FUDOCS_document_000000019250
    DOI: 10.1371/journal.pone.0061635
    Pubmed: 23637871
    Kontakt
    Institut für Parasitologie und Tropenveterinärmedizin

    Robert-von-Ostertag-Str. 7-13
    Gebäude 35, 22, 23
    14163 Berlin
    +49 30 838 62310
    parasitologie@vetmed.fu-berlin.de

    Abstract / Zusammenfassung

    Macrocyclic lactones (MLs) represent the major drug class for control of parasitic infections in humans and animals. However, recently reports of treatment failures became more frequent. In addition to human and ruminant parasitic nematodes this also is the case for the horse-nematode Parascaris equorum. Nevertheless, to date the molecular basis of ML resistance is still not understood. Unspecific resistance mechanisms involving transporters such as P-glycoproteins (Pgps) are expected to contribute to ML resistance in nematodes. Here, complete sequences of two P. equorum Pgps were cloned and identified as orthologs of Caenorhabditis elegans Ppg-11 and an unnamed Caenorhabditis briggsae Pgp designated as Pgp-16 using phylogenetic analysis. Quantitative real-time PCR was used to compare expression between tissues. Significantly higher PeqPgp-11 expression was found in the gut for both genders, whereas for PeqPgp-16 the body wall was identified as predominant expression site. Furthermore, Pgps were analyzed regarding their participation in resistance development. Using SeqDoC analyses, Pgp-sequences of P. equorum populations with different ML susceptibility were compared. This approach revealed three single nucleotide polymorphisms (SNPs) causing missense mutations in the PeqPgp-11 sequence which correlated with decreased ML susceptibility. However, no resistance associated differences in mRNA expression levels were detected between embryonated eggs of these populations. In contrast, comparison of two pre-adult groups with different ivermectin (IVM) susceptibility revealed the presence of the three SNPs and in addition statistically significant PeqPgp-11 overexpression in the group of worms with reduced susceptibility. These results indicate that Pgp-11 might be involved in IVM resistance in P. equorum as it shows increased expression in an IVM exposed life-cycle stage of an IVM resistant population as well as occurrence of putatively resistance associated SNPs in populations with reduced IVM susceptibility. These SNPs are promising diagnostic candidates for detection of ML resistance with potential also for other parasitic nematode species.