A team announces that it has identified a new type of cells evolving in human lungs. These cells appear to play a vital role in the proper functioning of the respiratory system. They could also inspire new treatments to combat the effects of certain smoking-related diseases.
Human lungs differ significantly from those of mice. In humans, the distal branches of the airways intertwine with the alveolar gas exchange niche, forming an anatomical structure known as the respiratory bronchioles. Due to the absence of these structures in mice, the cellular and molecular mechanisms that govern the respiratory bronchioles in the human lung remain still misunderstood .
Until now, laboratory research has relied on mouse models for its experiments and analyses, which has caused some frustration among scientists, aware of this different lung architecture.
In a recent study, a team led by Edward Morrisey of the University of Pennsylvania ultimately relied on emerging technologies to collect samples from healthy human donor lung tissue and analyze genes in individual cells.
Analysis of these tissues ultimately revealed the presence of a new type of cell called Respiratory Airway Secretory Cells (RAS) found in the bronchioles. Details of this work were reported in the journal Nature.
According to the study, these cells perform two main functions. First, they secrete molecules capable of maintaining the presence of mucus lining the bronchioles, thus maximizing the efficiency of the lungs. On the other hand, these cells seem to serve as progenitor cells . As a reminder, a progenitor cell is a cell capable of differentiating into another type of cell, in the same way as stem cells. Here, RAS cells could differentiate into alveolar type 2 (AT2) cells. These are a special type of alveoli that secrete a chemical used in part to repair other damaged alveoli.
In their study, the researchers also point out that while these cells are absent in mice, they are present in ferrets , whose respiratory systems are more similar to those of humans. As a result, they assume that most mammals of equal or larger size are likely to develop them as well.
The discovery of these new cells could make it possible to fight against certain respiratory diseases, such as chronic obstructive pulmonary disease (COPD) . This disease is characterized by progressive degeneration of lung tissue and partially reversible airway obstruction. As a result, the lungs struggle to absorb enough oxygen. The disease can also lead to emphysema. There are several risk factors such as smoking, respiratory problems during childhood or air pollution.
In theory, RAS cells should be able to prevent the effects of COPD by repairing damaged alveoli. However, researchers suspect that certain factors, particularly smoking , can damage them. We could thus ask ourselves whether or not the introduction of new RAS cells could help improve treatments or even cure the disease. This hypothesis will naturally have to be the subject of further studies.
