A completely new type of cell has been discovered in the human airway, and it may have a central role in the common genetic disorder cystic fibrosis.
The discovery came out of a census of all the cells in the windpipe and lungs, led by Allon Klein at Harvard Medical School and Aron Jaffe at the pharamaceutical company Novartis. They analysed gene activity in epithelial cells 鈥� which line membranes 鈥� taken from human lungs and the trachea of mice.
They found a specialised kind of epithelial cell in the lining of the trachea, which they named a pulmonary ionocyte. Its gene activity is similar to ionocytes that have been studied in frog skin and fish gills, where they move ions to regulate the pH of the liquid layer next to them. 鈥淭his may be the function of the pulmonary ionocyte as well, but we don鈥檛 know yet,鈥� says Jaffe.
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Cystic fibrosis clue
These new cells make up less than 2 per cent of all the cells in the airway epithelium, but they seem to be the main cell type where the gene involved in cystic fibrosis acts. This gene, called CFTR, makes a protein channel that lets certain ions move in or out of a cell.
A variety of mutations can disable this gene or its protein, which causes the normal mucus of the airway to become thicker and more acidic, and an ideal home for bacteria. This can lead to the respiratory infections that are characteristic of cystic fibrosis and contribute to lasting lung damage.
鈥淜nowing where the gene is active is a pretty important piece of information, particularly to help guide therapeutic development. It鈥檚 an important step on a long road to what will hopefully be developing new therapies for cystic fibrosis patients,鈥� Jaffe says.
Read more: Gene therapy works in cystic fibrosis for the first time
