Research/PIC Project 187
From Poultry Hub
Project title: Development of an RNA interference methodology to inhibit replication of Avian Influenza virus in chickens
Project Leader/s: Dr. Serguei Golovan
Organisation/s: University of Guelph
Date: January, 2008.
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Project overview
Vaccine based control of Avian Influenza (AI) in commercial poultry is considered, at best, only partially effective due to natural reservoirs of the virus in wild waterfowl and rapid random mutations of field strains. One possible control strategy is to stop the virus in infected cells from copying itself by using a molecule that interferes with this process. This is called RNA interference (RNAi) and its discoverers were awarded the Nobel Prize in 2006. This strategy has been extensively developed as an anti-viral drug in humans, and a similar approach would be extremely valuable for inhibiting viral replication and studying gene function in poultry. Dr. Serguei Golovan, together with his MSc. student Arusyak Abrahamyan and collaborators Drs. Eva Nagy and Shyayn Sharif, have been conducting experiments to determine whether RNAi works with chicken cells and could be used for stopping AI virus replication by designing and testing RNAi molecules.Read full report
Research
Vaccine based control of Avian Influenza (AI) in commercial poultry is considered, at best, only partially effective due to natural reservoirs of the virus in wild waterfowl and rapid random mutations of field strains. One possible control strategy is to stop the virus in infected cells from copying itself by using a molecule that interferes with this process. This is called RNA interference (RNAi) and its discoverers were awarded the Nobel Prize in 2006. This strategy has been extensively developed as an anti-viral drug in humans, and a similar approach would be extremely valuable for inhibiting viral replication and studying gene function in poultry. Dr. Serguei Golovan, together with his MSc. student Arusyak Abrahamyan and collaborators Drs. Eva Nagy and Shyayn Sharif, have been conducting experiments to determine whether RNAi works with chicken cells and could be used for stopping AI virus replication by designing and testing RNAi molecules. The Research To test whether RNAi is functional in chicken cells and could be used to stop AI virus replication, the researchers first obtained genome sequences of nucleocapsid protein from several avian influenza strains, including the recent H5N1 Asian variants. From this, they designed the RNAi molecule to test against avian influenza virus replication. The researchers needed to use a cell culture of avian origin so that the effects of the RNAi molecule could be studied in vitro (in the lab, rather than in a live bird). They chose CH-SAH (Chicken Hepatocellular Carcinoma) cell line. Because the mechanism by which RNAi machinery recognizes target sequences might vary between species, it was also decided to study the effects using a canine cell line. This was MDCK (Madin-Darby Canine Kidney) cell line. Virus stocks of four subtypes of avian influenza virus were created. These were turkey (H8N4), duck (H4N6), turkey (H6N2) and quail (H10N8). The viruses were propagated in each of the two cell lines described above, but the duck and quail strains showed higher susceptibility. The quail strain was chosen for further experiments because it was the only one that produced plaques (areas of cell distruction) in the CH-SAH cells. When the designed RNAi molecules were tested, they were found to decrease infective levels of avian influenza virus up to 158 fold compared with controls (where a mock procedure was performed). RNAi efficiency was even higher in the MDCK cells, with virus level being reduces up to 106 fold. The researchers think that the results for the avian cells could be improved by using a chicken specific promoter to develop the RNAi molecules – in the present research a mammalian promoter was used, based on successful use in previous research. Also, the design of the RNAi molecule was based on criteria developed for mammalian cells. Specific criteria could be developed for use with avian cells, resulting in a more efficient RNAi mioecule.Read full report
The Bottom Line
The results are very promising. In the long term, the introduction of such an RNAi molecule into the chicken genome may eventually lead to the production of birds that are completely resistant to influenza virus infection. Elimination of the circulation of avian influenza virus in poultry will protect farmers and consumers against possible transmission and decrease the probability of another flu pandemic.Read full report
Source
Poultry Industry Council
- 483 Arkell Road, Guelph, Ontario,Canada, N1H 6H8.
- pic@poultryindustrycouncil.ca
- http://www.poultryindustrycouncil.ca
