New knowledge on the development of lung alveoli

In order to obtain enough amounts of oxygen from the air, our lungs are subdivided into lots of small cavities called alveoli. In human beings the alveoli are formed around birth. The process leads to an expansion of the area for oxygen uptake and makes sure that the lung can supply the growing body with the needed amounts of oxygen.

Researchers from IGP have shown that a certain type of support cells called myofibroblasts are dependent on the protein PDGF-A during the time when the alveoli are formed. The need of PDGF-A during the formation of alveoli is known since before. However, which type of cells that respond to PDGF-A and how those cells lead to the formation of alveoli has been unknown until now. During the years, several hypotheses have been proposed and some of them have been referred to so many times that it has almost been forgotten that the hypotheses were never confirmed.

“We have established a number of genetically modified mouse strains. With the help of those we have been able to identify and analyze both the cells that produce PDGF-A and the cells that respond to the signals,” says Johanna Andrae, researcher at IGP, who has led the study.

By deleting the gene for PDGF-A specifically in selected lung cells the researchers have been able to show that the myofibroblasts need PDGF-A to assemble and form rings of the cytoskeletal protein actin. The actin rings restrain the expanding lung tissue which results in the formation of the alveoli.

The published project is based on basic research and the understanding for how alveoli are formed is important knowledge.

“We hope and think that our data will be the base for new, more targeted research projects that can lead to better treatment for both premature babies with bronchopulmonary dysplasia as well as for grown-ups with lung emphysema, caused e.g by COPD,” says Johanna Andrae.
 

More information:
Article in Development
Johanna Andrae’s research in Christer Betsholtz’ group