Researchers from the Centenary Institute and the University of Technology Sydney have revealed a surprising connection between the Toll-like receptor 7 (TLR7) protein, typically recognised for its antiviral defence function, and the exacerbation of lung conditions, particularly chronic obstructive pulmonary disease (COPD).
COPD, commonly associated with difficulties in breathing due to narrowed airways and damaged lung tissue, often arises from factors such as smoking or exposure to irritants, the institute said in a news release.
The research, led by Dr Gang Liu at the Centenary UTS Centre for Inflammation, challenges the conventional understanding of TLR7’s role by showcasing its heightened levels in individuals with COPD and experimental COPD models in mice.
Dr Liu, the lead researcher, noted that TLR7 is traditionally acknowledged for its essential role in supporting the immune system against specific viruses like those causing influenza, measles, and hepatitis C.
According to researchers, the unexpected revelation of elevated TLR7 levels in COPD patients prompted further investigation.
Through experiments with mice deficient in the TLR7 protein, researchers observed milder lung issues when exposed to COPD-like conditions.
Additionally, the drug imiquimod, known to activate TLR7, intensified lung problems in otherwise healthy mice.
“These preclinical findings shed light on TLR7’s unexpected role in aggravating lung conditions,” remarked Dr Liu.
A crucial aspect highlighted in the study is that TLR7 enhances the number and activity of mast cells, immune cells known to exacerbate COPD.
Dr Liu further explained, “Mast cells play a significant role in worsening COPD by initiating and perpetuating inflammation within the fragile lung tissues, making it harder for people to breathe. We found that higher TLR7 levels increase mast cell activity, escalating lung problems.”
Professor Phil Hansbro, senior study researcher and director of the Centenary UTS Centre for Inflammation emphasised the revelation of a previously unknown dimension of TLR7 concerning COPD.
“This study shows that TLR7, our body’s defence system against certain viruses, unexpectedly worsens lung problems such as COPD by working with mast cells,” said Professor Hansbro.
The research was published in the journal Nature Communications.
