Sneezing, runny nose and chills? You might blame the human rhinovirus (HRV), which causes 30 to 50 percent of common colds. But in reality, it's not the virus itself but HRV's ability to manipulate your genes that is the true cause of some of the most annoying cold symptoms.
For the first time, researchers have shown that HRV hijacks many of your genes and causes an overblown immune response that ends up with your nose being overblown.
The research, published in the first issue for November of the American Thoracic Society's clinical research journal, the American Journal of Respiratory and Critical Care Medicine, is the first study to comprehensively review gene changes caused by HRV.
"The study's findings are a major step toward more targeted cold prevention and treatment strategies while also serving as a valuable roadmap for the broader respiratory science community," said David Proud, PhD, a professor in the Department of Physiology and Biophysics at the University of Calgary, and lead author of the study. The study was done in collaboration with scientists at the University of Virginia and the Procter & Gamble Company.
Proud added that while colds are usually considered to be minor infections of the nose and throat, they can have much more serious health repercussions. "Rhinovirus is the major cause of the common cold, but it is also an important pathogen in more serious conditions, such as asthma and chronic obstructive pulmonary disease (COPD)," he said.
"Advances in our understanding of the biology of the common cold may eventually lead to improvements in treatment or methods for prevention of colds," said Dr. Ron Turner, of the University of Virginia, one of the study's authors.
The researchers recruited volunteers who were inoculated with either HRV or a sham inoculation and obtained cell scrapings from the nasal passages 8 and 48 hours after inoculation and assessed the genetic changes by microarray, also know as gene chip technology.
After 8 hours, there were virtually no differences between the control and the HRV-inoculated group, but by the 48-hour mark, more than 6500 genes has been significantly up- or down-regulated in the HRV subjects—many of the more highly up-regulated genes fell into two major categories: genes making antiviral proteins, including viperin; or genes making pro-inflammatory cytokines.