Flu season is upon us. With all that coughing and spluttering it may seem that there is little to ease the pain. But, some of the clever scientists at Washington State University have found a brain protein that boosts the healing power of sleep and speeds an animal’s recovery from the flu.
Research led by Professor James M. Krueger at WSU has determined that a brain-specific protein, the interleukin-1 receptor accessory protein (AcPb), is uniquely involved in sleep responses triggered by the influenza virus in mice. Without the protein, animals develop more severe symptoms of infection and die at higher rates than regular or control mice. The discovery could lead to alternative treatments for influenza and other infectious diseases, possibly by using intranasal sprays to stimulate the production of the brain protein.
It is known that sleep is necessary for a healthy immune system and plays a critical role in the body’s response to bacterial and viral infections. This new research adds to our knowledge demonstrating that recovery from infection involves AcPb and the cytokine interleukin-1. AcPb links up with interleukin-1 to help regulate sleep in healthy animals. It also prompts infected animals to spend more time sleeping during an illness.
Krueger and colleagues administered a form of the H1N1 strain of the influenza virus, which caused the 2009 pandemic, to the mice through intranasal spray. When infected, regular mice showed a typical sleep response, while those mice without the gene did not. AcPb knock-out mice also developed more serious symptoms, such as becoming chilled, sluggish and the loss of their normal circadian rhythms. Ultimately the AcPbKO mice then died at a higher rate.
“We knew that the virus replicated in the lungs,” said Krueger, “but we’ve discovered it also reaches parts of the brain – causing an inflammatory reaction involving interleukin-1 and AcPb. That reaction induces the increased sleep response that helps the body overcome an infection.”
Interleukin-1 also plays a role in influenza as one of the inflammatory molecules responsible for the freezing, aching, feverish misery of the flu. This finding expands our knowledge of the molecular pathways at play in the recovery from such infections.
The interleukin-1 – AcPb signalling complex is linked to a different molecule in the immune system called growth hormone releasing hormone (GHRH) and its receptor (GHRHR). GHRHR has previously been shown to be critical to the healing sleep responses induced by the influenza virus, which may offer an alternative approach to treat influenza and other such infections.