Study found 6,500 genes that were up- or down-regulated, according to paper in American Journal of Respiratory and Critical Care Medicine.
A group of researchers have identified several genes that are either up- or down-regulated after human rhinovirus (HRV) infection. They point out that it is not HRV by itself that causes the common cold but rather its ability to hijack genes and cause an overblown immune response.
During the research, scientists discovered that viral titer more than doubled in cells that had a viperin-producing gene knocked down, showing that viperin hinders HRV replication. “This had never been examined during rhinovirus infections,” according to David Proud, Ph.D., lead author of the study. “Some evidence existed that this protein, only discovered a few years ago, had effects on influenza, but nothing was known about its role in rhinovirus infections. So it was a bit unexpected.”
The team recruited volunteers and inoculated them with either HRV or a false inoculation. They then obtained cell scrapings from the nasal passages 8 and 48 hours after inoculation and assessed genetic changes by microarray.
After eight hours, there were virtually no differences between the control and the HRV-inoculated group. By the 48-hour mark, however, more than 6,500 genes, or 11,887 gene transcripts, had been significantly up- or down-regulated in the HRV subjects.
Many of the highly up-regulated genes fell into two major categories: genes making antiviral proteins including viperin or genes making proinflammatory cytokines. “This is the first comprehensive picture to identify several groups of genes that are likely to contribute to the proinflammatory and antiviral response,” says Dr. Proud.
The fact that these genes are associated with structural remodeling or alteration of the airways supports further study of the role of rhinovirus infections in airway remodeling in asthma, the researchers point out.
The study was done as a collaboration between scientists at the department of physiology and biophysics at the University of Calgary, the University of Virginia, and the Procter & Gamble Company. The research will be published in the November issue of the American Journal of Respiratory and Critical Care Medicine.
