Researchers have just discovered a new type of lung cell that we never knew existed. Excitingly, it could play a big role in cystic fibrosis, a debilitating lung condition that affects 30,000 Americans and over 70,000 people worldwide. Knowing about this new cell could potentially lead to better treatments for the disease.
The new discovery is described in two separate papers, both published in Nature, which you can read here and here. The cells are rare, making up less than 1 percent of cells in the airways. The researchers have called them pulmonary ionocytes as they have a similar gene expression pattern to ionocyte cells found elsewhere in the animal kingdom, which regulate ion transport and hydration in the gills of fish and the skin of frogs.
To make their discovery, the researchers analyzed thousands of lung cells in mice, mapping their locations and types to create an “atlas”. They then confirmed their findings using human lung tissue.
But what’s most exciting about the new cell is the fact that it expresses a gene known as CFTR. This gene is expressed by many lung cells, but it appears to mainly be expressed by pulmonary ionocytes. CFTR plays a critical role in cystic fibrosis. A mutation in this gene is what causes the disease.
As it's caused by genetics, cystic fibrosis is an inherited condition. Symptoms tend to begin in childhood, before slowly worsening over time. It causes a buildup of thick, sticky mucus in the airways leading to breathing problems and a higher risk of lung infections. It can also affect digestion by clogging up the pancreas with mucus. This prevents important digestive enzymes from reaching the gut. The disease can lead to other conditions like diabetes, infertility, and osteoporosis. While treatments exist to help ease the symptoms, cystic fibrosis has a significant impact on life expectancy.
All in all, it is a very unpleasant disease to endure, but the new lung cell discovery could help us tackle it.
"Cystic fibrosis is an amazingly well-studied disease, and we're still discovering completely new biology that may alter the way we approach it," said Jayaraj Rajagopal, senior author of one of the studies, in a statement. "At first, we couldn't believe that the majority of CFTR expression was located in these rare cells, but the graduate students and postdocs on this project really brought us along with their data."
The researchers believe their discovery could lead to the development of target therapies for cystic fibrosis. Knowing that the majority of CFTR gene expression takes place within pulmonary ionocytes could help scientists create gene therapies that can be delivered to those specific cells.