MicroRNAs, small ribonucleic acids that drive communication between cells, offer a new potential pathway for treating allergies and asthma, according to a new study.
Researchers found that a specific microRNA known as miR-1 has a direct impact on allergic airway inflammation and that altering its levels can help relieve the symptoms of asthma and allergies.
The method approaches treatment for allergies and asthma from an entirely new paradigm, one that focuses on “the language of cells,” says Shervin Takyar, associate professor and specialist in pulmonary disease at Yale University.
About 10 years ago, Takyar and colleagues began looking at the endothelial cells that line blood vessels within the nose and lung tissues where asthma and allergy symptoms arise.
In patients with asthma and rhinosinusitis (inflammation of the sinuses common to allergy sufferers), these blood vessels let in high numbers of eosinophils, the white blood cells that cause inflammation in the lungs and nasal passages
“We asked: ‘What if we could stop these blood cells at the gate?'” Takyar says.
The researchers zeroed in on one of these “gatekeepers,” miR-1, which directly affected whether the blood vessel gateways were open or shut.
“There’s a difference in the cellular language between people who naturally let eosinophils into their lungs and people who naturally don’t,” Takyar says. “We wanted to understand the language of the cells of these healthier people.”
Takyar and Geoffrey Chupp, professor of medicine and director of the Yale Center for Asthma and Airway Disease, studied both human lung samples and sinonasal tissues and found that patients whose tissue had low miR-1 levels had greater inflammation, poorer asthma control, and increased hospitalizations.
They showed that delivering miR-1 intranasally and altering miR-1 levels in the blood vessels of mouse models, could reverse the lung inflammation and reduce the white blood cells that cause allergy and asthma symptoms by more than 50%, as well as reducing airway inflammation, mucus levels, and asthma symptoms.
In the current study, published in the Journal of Allergy and Clinical Immunology, the researchers also show that administering miR-1 to human blood vessels directly can reduce the entry of human eosinophils into tissues.
Asthma rates are increasing, Takyar says, and new forms of asthma that existing medications don’t control well are on the rise. Some 300 million people worldwide suffer from allergic asthma. At the same time, doctors are diagnosing more people with chronic rhinosinusitis, which affects more than 10% of the US adult population.
Like those with asthma, many of these sufferers find no relief for their persistent congestion, runny noses, and headaches, even after surgery, Takyar says.
Delivering miR-1 to patients suffering from asthma and chronic rhinosinusitis who are not finding relief from current medications shows promise, he says.
“Here is a new language. We’re getting in line with how cells talk and using their language to close gateways, and we expect to see real improvements in severe asthma and allergy patients.”
Source: Brita Belli for Yale University