New research reveals how lung's immune cells develop after birth

Human lung macrophages begin to develop from birth, when the lungs are just beginning to take in air

However, with the help of a model, researchers at Karolinska Institutet have now been able to directly study the development of human macrophages in living lungs

"In the first type of development, lung macrophages originate from precursor cells already present in the fetal liver," said Tim Willinger, associate professor at the Harding School of Medicine at Karolinka Institutet, who led the this study

Gene expression is similar but functions are different

The researchers also investigated whether the origin of lung macrophages affects their function

"We found that fetal precursor cells divide faster than adult precursor cells," said Elza Evren, first author of the study and a doctoral student in Tim Willinger's group

In contrast, lung macrophages, derived from adult precursor cells, were strongly activated by interferon, a protein that has the task of defending against viral infection

The researchers also found that these lung macrophages are similar to pro-inflammatory macrophages, which are overactivated to cause severe lung damage in diseases such as COVID-19

Limiting lung damage, promoting new treatments

These new findings contribute to a better understanding of the origin and function of lung macrophages

The research was supported by the Swedish Research Council, SciLifeLab, Knut and Alice Wallenberg Foundation, Karolinska Institutet, Centre for Innovative Medicine (CIMED), Stockholm Region, Swedish Heart and Lung Foundation, Petrus och Augusta Hedlunds Stiftelse and the Royal Swedish Academy of Sciences Funded

Journal Reference :

1. Elza Evren, Emma Ringqvist, Jean-Marc Doisne, Anna Thaller, Natalie Sleiers, Richard A.