Washington [US], January 24 (ANI): A new study has found how lung macrophages develop and these new findings can help reduce organ damage and are important for the continued development of important treatments for lung diseases.
The research has been published in the ‘Journal of Experimental Medicine’.
Lung macrophages begin to develop in humans from birth when the lungs are first inflated with inhaled air. Despite the importance of lung macrophages in the immune system, their development in humans had not previously been known, as in vivo studies in humans are difficult to perform.
But with the help of a model, researchers at Karolinska Institutet have now been able to directly study the development of human macrophages in a living lung. The study discovered that lung macrophages develop in two different ways.
“In the first type of development, lung macrophages come from precursor cells that are already present in the fetus’ liver,” says Tim Willinger, associate professor at the Department of Medicine, Huddinge, Karolinska Institutet, who led the study.
“After we are born, these precursor cells move from the liver to the lungs via the bloodstream. In the lungs, they are then exposed to various growth factors, which helps them develop into” mature “lung macrophages. The second type of development occurs later in life. Then they develop from adults. precursor cells, so-called monocytes, which are found in the blood “, he added.
The researchers also investigated whether the origin of the lung macrophages affected their function. Here they could see that the lung macrophages, regardless of origin, had a similar gene expression but with different functions.
“We discovered that fetal precursor cells divide faster than adult precursor cells,” says the study’s first author, Elza Evren, a doctoral student in Tim Willinger’s research group.
“The fetus’ precursor cells therefore populate the lungs faster, which is important early in life to quickly remove microorganisms and other inhaled particles,” Evren added.
The lung macrophages derived from adult precursor cells were instead found to be strongly activated by interferon, a protein that has the task of defending itself against viral infections. It is therefore very likely that this particular type of lung macrophages has an important function in the immune system to help fight viruses.
The researchers also found that these lung macrophages are similar to pro-inflammatory macrophages, which can become overactivated and contribute to severe lung damage in diseases such as COVID-19.
The new findings contribute to a better understanding of the origin and function of lung macrophages. The human fetal progenitor cell that the researchers have identified is a potential cell that can be targeted at regenerating tissue-protective macrophages, limiting organ damage and promoting tissue repair in an injured lung. These findings may also support the development of new treatments for a number of lung diseases.
The study was supported by grants from the Swedish Research Council, SciLifeLab, Knut and Alice Wallenbergs Stiftelse, Karolinska Institutet, Centrum för Innovativ Medicin (CIMED), Region Stockholm, Hjärt-Lungfonden, Petrus och Augusta Hedlunds Stiftelse och Kungl. Academy of Sciences.
One of the authors from Yale University has reported conflicts of interest, which are described in detail in the scientific article. (ANI)