title: SLO-1-channels of parasitic nematodes reconstitute locomotor behaviour and emodepside sensitivity in Caenorhabditis elegans slo-1 loss of function mutants.
abstract: The calcium-gated potassium channel SLO-1 in Caenorhabditis elegans was recently identified as key component for action of emodepside, a new anthelmintic drug with broad spectrum activity. In this study we identified orthologues of slo-1 in Ancylostoma caninum, Cooperia oncophora, and Haemonchus contortus, all important parasitic nematodes in veterinary medicine. Furthermore, functional analyses of these slo-1 orthologues were performed using heterologous expression in C. elegans. We expressed A. caninum and C. oncophora slo-1 in the emodepside-resistant genetic background of the slo-1 loss-of-function mutant NM1968 slo-1(js379). Transformants expressing A. caninum slo-1 from C. elegans slo-1 promoter were highly susceptible (compared to the fully emodepside-resistant slo-1(js379)) and showed no significant difference in their emodepside susceptibility compared to wild-type C. elegans (p = 0.831). Therefore, the SLO-1 channels of A. caninum and C. elegans appear to be completely functionally interchangeable in terms of emodepside sensitivity. Furthermore, we tested the ability of the 5' flanking regions of A. caninum and C. oncophora slo-1 to drive expression of SLO-1 in C. elegans and confirmed functionality of the putative promoters in this heterologous system. For all transgenic lines tested, expression of either native C. elegans slo-1 or the parasite-derived orthologue rescued emodepside sensitivity in slo-1(js379) and the locomotor phenotype of increased reversal frequency confirming the reconstitution of SLO-1 function in the locomotor circuits. A potent mammalian SLO-1 channel inhibitor, penitrem A, showed emodepside antagonising effects in A. caninum and C. elegans. The study combined the investigation of new anthelmintic targets from parasitic nematodes and experimental use of the respective target genes in C. elegans, therefore closing the gap between research approaches using model nematodes and those using target organisms. Considering the still scarcely advanced techniques for genetic engineering of parasitic nematodes, the presented method provides an excellent opportunity for examining the pharmacofunction of anthelmintic targets derived from parasitic nematodes.
authors.affiliation: Institute for Parasitology, University of Veterinary Medicine Hannover, Hannover, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Welz
authors.forename: Nina
authors.initials: N
authors.lastname: Krüger
authors.forename: Monika
authors.initials: M
authors.lastname: Schniederjans
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Miltsch
authors.forename: Jürgen
authors.initials: J
authors.lastname: Krücken
authors.forename: Marcus
authors.initials: M
authors.lastname: Guest
authors.forename: Lindy
authors.initials: L
authors.lastname: Holden-Dye
authors.forename: Achim
authors.initials: A
authors.lastname: Harder
authors.forename: Georg
authors.initials: G
authors.lastname: von Samson-Himmelstjerna
mesh_terms: D000722:Ancylostoma / Q000187:drug effects / Q000235:genetics; D000818:Animals; D000871:Anthelmintics / Q000494:pharmacology; D017173:Caenorhabditis elegans / Q000187:drug effects* / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D047630:Depsipeptides / Q000494:pharmacology*; D005786:Gene Expression Regulation; D006189:Haemonchus / Q000187:drug effects / Q000235:genetics; D051036:Large-Conductance Calcium-Activated Potassium Channels / Q000235:genetics / Q000378:metabolism*; D009043:Motor Activity; D009154:Mutation; D009183:Mycotoxins / Q000494:pharmacology; D010641:Phenotype; D011401:Promoter Regions, Genetic; D017422:Sequence Analysis, DNA; D014170:Transformation, Genetic; D014251:Trichostrongyloidea / Q000187:drug effects / Q000235:genetics
chemical_list: D000871:Anthelmintics; D029742:Caenorhabditis elegans Proteins; D047630:Depsipeptides; D051036:Large-Conductance Calcium-Activated Potassium Channels; D009183:Mycotoxins; C494845:slo-1 protein, C elegans; C003626:tremortin; C468987:emodepside