Parasitic worm genome uncovers potential drug targets

Barber Pole worm genome provides an essential platform to understand drug resistance in worms

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Genome Biology 2013
Gene expression across the Haemonchus contortus. Numbers of genes significantly up–regulated (red) and down- regulated (blue) between life stages.
Researchers have identified five enzymes that are essential to the survival of a parasitic worm that infects livestock worldwide and is a great threat to global food security. Two of these proteins are already being studied as potential drug targets against other pathogens.

The team sequenced the genome of Haemonchus contortus, or the barber pole worm, a well-studied parasitic worm that resides in the gut of sheep and other livestock globally. This genome could provide a comprehensive understanding of how treatments against parasitic worms work and point to further new treatments and vaccines.

The barber pole worm or H. contortus is part of a family of gastrointestinal worms that are endemic on 100 per cent of farms and are estimated to cost the UK sheep industry alone more than £80 million pounds each year. H. contortus has become resistant to all major treatments against parasitic worms, so its genome is a good model to understand how drug resistance develops in this complex group of closely related parasites and will also reveal further potential drug and vaccine targets.

“Our reference genome allows researchers to understand how H. contortus and other worms of this type acquire resistance to a wide range of anthelmintics – the drugs used to treat worm infections. Seeing a common theme of drug resistance in this well-characterised worm is extremely important because both people and animals are reliant on so few treatments against parasitic worms.”

Dr James Cotton Senior author from the Wellcome Trust Sanger Institute

The team sequenced the genome of a strain of H contortus that was susceptible to all major classes of drugs against parasitic worms. By comparing this sequence with that of worms that have acquired drug resistance, the researchers expect to reveal a wealth of information about how and why resistance has occurred.

“The H. contortus genome provides a rich and essential platform for future research in this and other types of parasitic worms. With the world population set to exceed nine billion by the year 2050, improving the security of our food supply is crucial. Getting to grips with genomes such as that of H. contortus is our best option to tackle the issue of drug resistance and develop new drugs against parasitic worms to address this issue.”

Professor Neil Sargison Author from the University of Edinburgh, Royal (Dick) School of Veterinary Studies

To generate a rich source of potential vaccine and drug target candidates, the team identified a set of genes that are more active in certain stages of the parasite life cycle and within the parasite’s gut. They also identified five metabolic chokepoints – enzymes that are essential for a parasite’s survival. Two of these enzymes are already being studies as potential drug targets; one against Mycobacterium tuberculosis and another against another type of worm.

To discover these targets, the team determined when and where each gene is turned on or off in the cells and tissues of H. contortus to reveal new insights into the worm’s lifecycle. The result is the most extensive dataset of its kind for any gastrointestinal worm and is expected to provide a valuable resource for future investigations.

The researchers also described the full gene repertoires for known drug target families. This gives a comprehensive understanding of how several important treatments work against worms and begins to unravel why resistance has occurred in these genes.

“Not only is this worm closely related to many other parasites of livestock it is also similar to some species of worms in humans. This makes it an extremely important model parasite species for experimental studies.

“Revealing new drug targets against H. contortus could provide much-needed new treatment opportunities against parasitic worms in both animals and humans.”

Professor John Gilleard Joint senior author from the University of Calgary Faculty of Veterinary Medicine

More information

Funding

The Haemonchus contortus genome project is funded by the Wellcome Trust.

Participating Centres

  • Institute of Infection, Immunity and Inflammation, College of Medical, Sciences, University of Glasgow, Glasgow, United Kingdom
  • Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
  • Division of Parasitology, Department of Infectious Disease, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-­-1692 Japan
  • Institute of Parasitology, McGill University, Ste Anne de Bellevue, Quebec, Canada
  • Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
  • Disease Control, Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, United Kingdom
  • Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
  • Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
  • Department of Infectious Diseases and Center for Tropical and Emerging Global Disease, University of Georgia, Athens, USA

Publications:

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Selected websites

  • The University of Calgary

    The University of Calgary is a leading Canadian university located in the nation’s most enterprising city. The university has a clear strategic direction to become one of Canada’s top five research universities by 2016, where research and innovative teaching go hand in hand, and where we fully engage the communities we both serve and lead. This strategy is called Eyes High, inspired by the university’s Gaelic motto, which translates as ‘I will lift up my eyes.’

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  • The Wellcome Trust Sanger Institute

    The Wellcome Trust Sanger Institute is one of the world’s leading genome centres. Through its ability to conduct research at scale, it is able to engage in bold and long-term exploratory projects that are designed to influence and empower medical science globally. Institute research findings, generated through its own research programmes and through its leading role in international consortia, are being used to develop new diagnostics and treatments for human disease.

  • The Wellcome Trust

    The Wellcome Trust is a global charitable foundation dedicated to achieving extraordinary improvements in human and animal health. We support the brightest minds in biomedical research and the medical humanities. Our breadth of support includes public engagement, education and the application of research to improve health. We are independent of both political and commercial interests.