For the first time, researchers have mapped the building blocks of the lungs and airways of individuals who have asthma, as well as those who don’t have the chronic lung condition.
The research, published in Nature Medicine, is part of the Human Cell Atlas project. The initiative seeks to create a collection of cellular reference maps that characterize each of the thousands of cell types in the human body and where they are found.
“This global view of the airway wall cellular landscape opens up new perspectives on lung biology and molecular mechanisms of asthma,” wrote the authors of the research from Wellcome Sanger Institute in England and University Medical Center Groningen.
To create the cell maps, the researchers employed single cell technology to focus on samples from 17 individuals, looking at cell types in normal lungs and upper airways. By analyzing more than 36,000 cells from several areas of the lung and the nasal area, they could see which genes were active in each cell and they could label each specific cell type.
The researchers also looked at cell types and activities from samples of six asthma sufferers and compared them to the lungs of people who do not have asthma. They detected differences between the cells of the lungs in those with asthma and those without asthma.
What were the biggest differences the researchers saw between normal lungs and asthmatic lungs?
First off, they detected many more inflammatory Th2 cells in the asthmatic lungs, and these cells sent the majority of cellular signals in asthma patients. On the other hand, in normal lungs, there is a broad range of cell communications.
In addition, for the first time, they observed a cell state, known as the mucocilliated state, which produces mucus in patients with asthma.
“We saw there is a specific cell type in the lungs of people with asthma that among other things secretes high levels of mucus,” says Dr. Felipe Vieira Braga, an author on the paper. “High levels of mucus in the lungs can cause coughing, which also is characteristic of asthma.”
Asked whether this could mean that potential new therapeutic targets for asthma relief might be identified, Dr. Braga explains: “Potentially yes. We now know in which cells in the lungs every gene is expressed. This means if companies want to develop specific treatments to target specific genes, they can use this information to estimate if it could have a potential therapeutic impact or not, depending on the cell where it is expressed.”
Asthma affects more than 25 million people in the United States, according to the Centers for Disease Control. Some 1.8 million people in the U.S. visited an Emergency Department for asthma-0ralted care in 2016 and 189,000 were hospitalized because of the disease.
This research could be helpful as it could aid scientists looking for new drug targets that could potentially keep cells from responding to inflammatory signals and help to bring about normal cell function in those with asthma.
Dr. Braga adds: “We have defined the baseline gene expression of the cell types in the healthy lungs. This means that people can now use this information to compare to the differences found in other lung diseases, such as cystic fibrosis and chronic obstructive pulmonary disease.”
Felipe A. Vieira Braga et al. “A cellular census of human lungs identifies novel cell states in health and in asthma.” 17 June 2019. Nature Medicine.
Asthma and Allergy Foundation of America.
Centers for Disease Control and Prevention.
Last updated on 10/8/19.