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Cystic fibrosis: fighting bacterial superinfection

Identification of molecules controlling the organism's anti-infectious and anti-inflammatory response.

The symptoms of people suffering from respiratory diseases, such as cystic fibrosis, get worse when they contract a bacterial infection. Some bacteria are resistant to antibiotics. Researchers from Inserm's Saint-Antoine Research Center and Sorbonne University are studying the organism's natural responses for fighting these bacteria.

Bacterial infections and respiratory diseases

In various respiratory diseases, infections caused by bacteria make patient symptoms worse. This is particularly the case with the Pseudomonas aeruginosa bacterium. This highly resistant bacterium is difficult to treat clinically; the mortality rate is 50% in vulnerable (immunosuppressed) patients. This pathogenic bacterium chronically colonizes the airways of 80% of adult patients suffering from cystic fibrosis. Cystic fibrosis is a rare genetic disorder that primarily affects the respiratory tracts and the digestive system. Pulmonary infections by Pseudomonas aeruginosa in patients with this disease significantly increase the severity of respiratory impairment. As this bacterium is resistant to many antibiotics, new strategies need to be found to combat the pulmonary infections they cause.

Saint-Antoine Research Center

An alternative to antibiotics

Researchers from Inserm's Saint-Antoine Research Center and Sorbonne University are studying a strategy that complements antibiotics. These antibiotics attack the bacterium directly. The researchers are suggesting instead reinforcing the antibacterial response of the lung cells and modulating the pulmonary inflammatory response so that it can adapt to the infectious attack.

The research team has identified, in the bronchial epithelial cells - the cells covering the bronchial tubes - small molecules capable of regulating gene expression1. These molecules, known as microDNA, are present in all our cells and help to ensure that our organism continues working by regulating the production of proteins. Amongst the microDNA studied, some are involved in regulating the organism's inflammatory response or in the expression of antimicrobial molecules.

The aim is now to characterize the exact role of this microDNA, which could help to better fight infection and regulate inflammation in patients with cystic fibrosis. Pseudomonas aeruginosa is also involved in other respiratory diseases and sufferers could benefit from these advances.

1. Gene expression means all of the biochemical processes whereby the hereditary data stored in a gene is read to produce molecules that will play an active role in cellular functioning, such as proteins.

How the Air Liquide Foundation is participating

The €50,000 Foundation grant is used for the analysis of the microDNA by the Pasteur Institute's Genomic platform and to buy the consumables necessary for implementation of the project (cell culture, molecular biology, analysis and modulation of microDNA expression, etc.).