Structural model, functional modulation by ivermectin and tissue localization of Haemonchus contortus P-glycoprotein-13

https://doi.org/10.1016/j.ijpddr.2018.02.001Get rights and content
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Highlights

  • H. contortus Hco-Pgp-13 is ortholog of C. elegans Cel-Pgp-12, Cel-Pgp-13, Cel-Pgp-14.

  • Hco-Pgp-13 was modeled by homology with the Cel-Pgp-1 crystal structure.

  • In silico docking showed high affinity of ivermectin and actinomycin D to Hco-Pgp-13.

  • Ivermectin and actinomycin D modulated Hco-Pgp-13 ATPase activity with high affinity.

  • Hco-Pgp-13 localization to H. contortus epithelial, pharyngeal and neuronal tissues.

Abstract

Haemonchus contortus, one of the most economically important parasites of small ruminants, has become resistant to the anthelmintic ivermectin. Deciphering the role of P-glycoproteins in ivermectin resistance is desirable for understanding and overcoming this resistance. In the model nematode, Caenorhabditis elegans, P-glycoprotein-13 is expressed in the amphids, important neuronal structures for ivermectin activity. We have focused on its ortholog in the parasite, Hco-Pgp-13. A 3D model of Hco-Pgp-13, presenting an open inward-facing conformation, has been constructed by homology with the Cel-Pgp-1 crystal structure. In silico docking calculations predicted high affinity binding of ivermectin and actinomycin D to the inner chamber of the protein. Following in vitro expression, we showed that ivermectin and actinomycin D modulated Hco-Pgp-13 ATPase activity with high affinity. Finally, we found in vivo Hco-Pgp-13 localization in epithelial, pharyngeal and neuronal tissues. Taken together, these data suggest a role for Hco-Pgp-13 in ivermectin transport, which could contribute to anthelmintic resistance.

Keywords

Nematode
Haemonchus contortus
ABC transporters
P-glycoprotein
Ivermectin
Homology modeling

Abbreviations

ABC
ATP-binding cassette
ACD
actinomycin D
AH
anthelmintic
BlastP
protein Basic Local Alignment Search Tool
bp
base pairs
Cel
Caenorhabditis elegans
Hco
Haemonchus contortus
Hsa
Homo sapiens
IVM
ivermectin
MDR
multidrug resistance
ML
macrocyclic lactone(s)
Mmu
Mus musculus
NBD
nucleotide binding domain
PDB
Protein data bank
Pgp
P-glycoprotein
QMEAN
Qualitative Model Energy Analysis
RMSD
root mean square deviation
SNP
single nucleotide polymorphism
TM(D)
transmembrane (domain)

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1

Contributed equally.