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▲ Mechanisms regulating pulmonary neutrophils in the pulmonary environment. Prostaglandin E2 produced in the lungs regulates various functions by regulating the gene expression of neutrophils that are attached to the blood vessels of the lungs. These functional differences in lung neutrophils prevent excessive damage to the lungs in acute respiratory distress syndrome caused by infectious substances. |
Neutrophils, which account for the largest proportion of immune cells in our body’s blood, are leukocytes that circulate through blood vessels. When bacteria enter the body, they arrive first to the site of infection and attack and remove bacteria. The role has been newly defined.
The National Research Foundation of Korea (Chairman Gwangbok Lee) announced that Professor Bae Oe-shik (Sungkyunkwan University) and his research team discovered that lung neutrophils play a role in protecting the lungs from infection or inflammation.
The lung is a core organ of our body, and it is known that the immune response is suppressed because it can cause serious lung damage if an excessive inflammatory reaction occurs during pathogen infection.
In addition, it is known that neutrophils exist in normal lungs that are not infected with bacteria, but how are they different from neutrophils in bone marrow or blood, what factors determine the characteristics of lung neutrophils, and what functions do pulmonary neutrophils play in pulmonary inflammatory diseases? It has not yet been revealed whether
The research team isolated neutrophils from the lungs and confirmed that lung neutrophils have different characteristics from bone marrow and blood neutrophils through RNA sequencing and flow cytometry analysis.
Functionally, lung neutrophils induce reactive oxygen production that can effectively remove infiltrating bacteria, but the production of inflammatory cytokines by bacterial endotoxin stimulation was significantly reduced compared to bone marrow neutrophils.
This indicates that while pulmonary neutrophils effectively defend once morest infectious bacteria, they can be controlled so that excessive immune responses in the lungs do not occur during pathogen infection.
On the other hand, it was confirmed that prostaglandin E2 (PGE2), which is abundantly present in lung tissue, plays a role in generating neutrophils with immunosuppressive function while allowing neutrophils circulating in blood vessels to stay in the lungs.
Furthermore, it was found that prostaglandin E2 induces pulmonary neutrophils to have an anti-inflammatory function by generating transglutaminase2 (Tgm2) through activation of protein kinase A (PKA).
With this achievement, the research team confirmed that neutrophils residing in the lungs can control the inflammatory response in the lungs, providing a clue to the possibility of treating lung diseases targeting neutrophils.
The results of this study were published online on June 9 in the international scientific journal ‘Blood’ in the field of hematology.
