The host genome also plays a role in bacterial colonization of the lung.

The lung is not sterile, in contrast to previous assumptions. It contains a diverse microbial ecosystem that is associated with diseases like cystic fibrosis, asthma, or COPD. Smoke, antibiotics, and nutrition are important factors affecting the composition and stability of the microbial community in the lung.

The influence of host genetics on lung microbiome is still not fully understood. Given the challenge of obtaining lung samples and the low abundance of microorganisms, a research team from the Leibniz ScienceCampus EvoLUNG conducted detailed studies on the lung microbiome in a mouse model. As published in the journal Animal Microbiome, the team investigated links between individual bacterial species in the lung and markers in the host genome to identify genes that may affect susceptibility to disease and found seven genomic regions for eight bacterial traits. “We were able to identify several promising genes related to immune and inflammatory responses, lung functioning, and disease susceptibility,” says Professor John Baines, who headed the study.

The study used state-of-the-art molecular biology techniques to quantify bacterial species present in the lungs of the investigated mice, and the findings provided the first evidence of the role of host genetic variation in the lung microbiota. “IL-10 knockout mice had fewer Lactobacilli than the non-knockout animals,” says co-author Dr. Meriem Belheouane from the Research Center Borstel, Leibniz Lung Center. Host genetic variations were also found for the number of Pelomonas, another common bacterial species in the lungs.