La mutation du récepteur TLR5 relie le microbiome pulmonaire à la progression de l'IPF

Mice lacking the $Tlr5$ gene develop significantly more lung fibrosis, lose more weight, and face lower survival rates when subjected to lung injury. This finding, published in Science Translational Medicine, establishes a previously unknown genetic connection between the lung microbiome and idiopathic pulmonary fibrosis (IPF).

TLR5 Dysfunction Accelerates Lung Scarring

Stavros Garantziotis and his team at the National Institute of Environmental Health Sciences discovered that the $Tlr5$ gene, which encodes a receptor responsible for recognizing bacteria, plays a protective role in the lungs. In healthy models, TLR5 receptors in airway cells activate in response to lung injury, preventing the overgrowth of harmful bacteria.

When researchers deleted the $Tlr5$ gene in mice, the protective mechanism failed. These mice exhibited reduced microbial diversity and diminished antimicrobial activity in the cells lining their lungs. This microbial imbalance directly correlated with increased fibrotic tissue development, suggesting that the lung microbiome's state is a primary driver of IPF progression.

A New Pathway for Fibrotic Disease

While current IPF treatments can slow disease progression, they fail to improve patient symptoms because the underlying biological triggers remain largely unknown. The identification of the TLR5 receptor provides a specific, actionable pathway. Unlike traditional fibrotic research, this approach connects immune response and microbial regulation to tissue scarring.

Brian Oliver from the University of Technology Sydney notes that the involvement of the TLR5 receptor is a highly novel concept for a fibrotic lung disease. Because the receptor is activated by injury—such as those caused by smoking or environmental exposure—targeting the protein with specific drugs could potentially prevent the transition from acute injury to chronic, life-threatening fibrosis. This discovery shifts the focus of IPF therapeutics toward managing the lung's microbial environment through genetic and protein-based interventions.

Source: This mysterious lung disease affects millions of people - but a drug tested in mice shows promise
Domain: nature.com