Low cost whole-organism screening of compounds for anthelmintic activity.
Due to major problems with drug resistance in parasitic nematodes of animals, there is a substantial need and excellent opportunities to develop new anthelmintics via genomic-guided and/or repurposing approaches. In the present study, we established a practical and cost-effective whole-organism assay for the in vitro-screening of compounds for activity against parasitic stages of the nematode Haemonchus contortus (barber's pole worm). The assay is based on the use of exsheathed L3 (xL3) and L4 stages of H. contortus of small ruminants (sheep and goats). Using this assay, we screened a panel of 522 well-curated kinase inhibitors (GlaxoSmithKline, USA; code: PKIS2) for activity against H. contortus by measuring the inhibition of larval motility using an automated image analysis system. We identified two chemicals within the compound classes biphenyl amides and pyrazolo[1,5-α]pyridines, which reproducibly inhibit both xL3 and L4 motility and development, with IC50s of 14-47 μM. Given that these inhibitors were designed as anti-inflammatory drugs for use in humans and fit the Lipinski rule-of-five (including bioavailability), they show promise for hit-to-lead optimisation and repurposing for use against parasitic nematodes. The screening assay established here has significant advantages over conventional methods, particularly in terms of ease of use, throughput, time and cost. Although not yet fully automated, the current assay is readily suited to the screening of hundreds to thousands of compounds for subsequent hit-to-lead optimisation. The current assay is highly adaptable to many parasites of socioeconomic importance, including those causing neglected tropical diseases. This aspect is of major relevance, given the urgent need to deliver the goals of the London Declaration (http://unitingtocombatntds.org/resource/london-declaration) through the rapid and efficient repurposing of compounds in public-private partnerships.
Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
Sarah
S
Preston
Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
Abdul
A
Jabbar
Medicinal Chemistry, Monash University Institute of Pharmaceutical Sciences (MIPS), Monash University, Parkville, Victoria 3052, Australia.
Cameron
C
Nowell
Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria.
Anja
A
Joachim
Institute of Parasitology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria.
Bärbel
B
Ruttkowski
Medicinal Chemistry, Monash University Institute of Pharmaceutical Sciences (MIPS), Monash University, Parkville, Victoria 3052, Australia.
Jonathan
J
Baell
Medicinal Chemistry, Monash University Institute of Pharmaceutical Sciences (MIPS), Monash University, Parkville, Victoria 3052, Australia.
Tony
T
Cardno
Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
Pasi K
PK
Korhonen
Faculty of Science and Technology, School of Applied and Biomedical Sciences, Federation University, Churchill, Victoria 3842, Australia.
David
D
Piedrafita
Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
Brendan R E
BR
Ansell
Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
Aaron R
AR
Jex
Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia; Structural Chemistry Program, Eskitis Institute, Griffith University, Brisbane, Queensland 4111, Australia.
Andreas
A
Hofmann
Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia. Electronic address: robinbg@unimelb.edu.au.
Robin B
RB
Gasser
D000818:Animals; D000871:Anthelmintics / Q000191:economics / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical / Q000191:economics* / Q000379:methods*; D004351:Drug Resistance; D006188:Haemonchiasis / Q000469:parasitology; D006189:Haemonchus / Q000187:drug effects* / Q000254:growth & development; D006801:Humans
D000871:Anthelmintics
Anthelmintic screening; Automated imaging analysis; Biphenyl amide; Haemonchus contortus; Kinase inhibitor; Motility assay; Pyrazolo[1,5-α]pyridine