New lung cell type discovered

Researchers found a previously- unknown airway cell type

Boston, Aug. 3: Researchers have discovered a previously unknown airway cell type that may help cure a genetic disorder that affects mostly the lungs.

Two studies, published in the journal Nature, also revealed the characteristics of other new, rare and poorly understood cell types, which expands the current understanding of lung biology and disease.

These cells appear to be the primary source of activity of the CFTR gene, mutations to which cause cystic fibrosis, a multiorgan disease that affects more than 70,000 people worldwide.

Despite decades of study on CFTR and progress in treating the disease, there is still no cure, according to researchers.

The new findings show that CFTR activity is concentrated in a small, previously unknown population of cells, which serve as promising targets for future therapeutic strategies against cystic fibrosis. The researchers named the cells “pulmonary ionocytes” due to similarities with ionocytes, a type of cell found in the gills of freshwater fish and frog skin, which regulate salt balance.

“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 from Harvard Medical School ( HMS) in the US.

“We have the framework now for a new cellular narrative of lung disease,” Rajagopal said.

The teams, including researchers from the Massachusetts General Hospital, set out to build an atlas of the cells that make up the airway.

Using single- cell sequencing technology, they analysed gene expression in tens of thousands of individual cells isolated from human and mouse airways — one cell at a time. Comparing patterns of gene expression and using previously described cells as references, the teams created comprehensive catalogues of different cell types and states, as well as their abundance and distribution. The teams’ analyses mapped out the genetic identities of both known and previously undescribed cell types.

One new cell type, which they named pulmonary ionocytes, was particularly striking as these cells expressed higher levels of CFTR than any other cell.

Pulmonary ionocytes appear to play a role in this process, which is necessary for clearing mucus from the airways, researchers said.