Researchers from the Boston University School of Medicine (BUSM) have identified a new type of lung cell that is important to the body’s natural immune defense against the Streptococcus pneumoniae bacteria, one of the leading causes of pneumonia around the world. Their study has been published in The Journal of Clinical Investigation.
Two types of cells can be found in the human body. Germ cells are used to make sperm and eggs, while everything else is created via somatic cells. Germ cells and somatic cells are incredibly different — no surprise given their dramatically different roles in human biology.
Previously, scientists believed that the MIWI2 gene, one of a group of genes that help sperm develop properly, was only expressed in male germ cells. However, the BUSM researchers discovered that not only is MIWI2 expressed in somatic cells in the body, its expression distinguishes a unique family of multi-ciliated cells that line the lungs’ upper airways and help the body fight infection.
“These ciliated cells have hair-like projections that function to sweep mucous and other foreign material out of the lung. However, what sets this new population of ciliated cells apart is that they express the MIWI2 protein and, in this report, were found to have a specialized role in controlling lung infection,” BUSM assistant professor of medicine and corresponding author Matthew Jones explained in a press release.
According to the Centers for Disease Control and Prevention (CDC), 50,000 people die from pneumonia every year in the U.S., and worldwide, it is the leading infectious cause of death amongst children under the age of five. The researchers are optimistic that their findings may prompt new, non-traditional approaches to fighting this potentially deadly infection.
“Pneumonia is a worldwide public health burden and a leading cause of death from infection. Together with the increasing prevalence of antibiotic resistant strains of bacteria, it is now more critical than ever to develop new methods for combating this pathogen,” Jones stated in the release. “It is our hope that we can leverage these molecular insights to develop novel therapeutic strategies.”
The researchers believe the new pattern of gene expression and corresponding cell type may also lead to an improved understanding of the mechanisms behind inflammatory diseases that involve changes in the cellular composition of the airway, such as asthma and chronic obstructive pulmonary disease (COPD). Next steps will include pursuing new investigations of how the lungs react to infectious bacteria.