In a study published this week in the Journal of Virology, University of British Columbia researchers identified a number of tiny but powerful genetic regulators that are hijacked by avian and swine flu viruses during human infection.
The study is the first to compare the role played by human microRNAs, or small molecules that control the expression of multiple genes, in the life cycle of two influenza viruses. The research discovered two largely distinct sets of microRNAs involved in pandemic (2009) swine-origin H1N1 virus and the highly pathogenic avian-origin H7N7 strain, with only a small subset of microRNAs involved in the regulation of both infections.
“We know that microRNAs are implicated in many types of cancers and other human diseases, but focusing on microRNA signatures in viral infection breaks new ground,” says François Jean, Associate Professor in the Department of Microbiology and Immunology and Scientific Director of the Facility for Infectious Disease and Epidemic Research (FINDER) at UBC.
“Host-virus interplays are certainly complex, but our discovery points to a new level of cross-communication between viruses and the human cells in which they reproduce,” notes Jean. “The finding that a significant number of these microRNAs are transported in microparticles – known as exosomes –involved in intercellular communication is also very exciting. It raises the question as to what role these exosome-associated regulators may play in the onset and spread of the flu virus.”
The researchers believes that the discovery of the unique microRNA signatures associated with pandemic and deadly influenza viruses will assist in developing novel antiviral treatments that do not contribute to increased drug resistance.
The project was supported by the Canadian Institutes of Health Research and the Public Health Agency of Canada.