A new study suggests that activating an enzyme known as ALDH1A1 could help protect the lungs from air pollution, particularly in vulnerable groups such as pregnant women, children and those with asthma or COPD.
Given that air pollution is the second leading cause of death worldwide, it’s surprising that we don’t fully understand how it harms the body, much less if there’s any remedial action people can take.
Now, researchers at Osaka University believe they have taken an significant step toward answering that question in a new paper published in The Journal of Clinical Investigation.
The team investigated how PM2.5 damages the structures inside our airways by exposing laboratory mice to PM2.5 in controlled conditions. They then examined the mice’s respiratory systems, focusing on changes at the cellular and molecular level.
They found that the pollutants triggered oxidative stress, a process in which unstable molecules called free radicals cause cellular damage. This stress led to the creation of lipid peroxide-derived aldehydes, highly reactive chemicals known to damage lung tissue.
One of the main casualties of this chemical assault were the cilia that line the airways. Cilia play a crucial role in lung health by sweeping out mucus, debris, and pathogens. When these structures were damaged by the aldehydes, the airways lost their ability to self-clean, increasing the risk of infections and chronic respiratory conditions.
Lead author, Noriko Shinjyo said: ‘Our results were quite informative. We found that PM2.5 air pollutants negatively affect mucociliary clearance, a major protective mechanism in the respiratory tract. Mucociliary clearance basically involves trapping pollutants in a sticky mucus and then sweeping the pollutants out the airway with hair-like projections called cilia.’
The team then explored how the body might reverse this damage. They focused on a family of protective enzymes called ALDH (aldehyde dehydrogenases), specifically one called ALDH1A1, which helps neutralise harmful aldehydes.
Yasutaka Okabe, senior author. said: ‘Aldehyde dehydrogenase (ALDH1A1) is an enzyme that plays an important role in protection against aldehydes. We used experimental mice that lacked ALDH1A1 to investigate the impact of air pollutants without the gene. As expected, the mice had impaired cilia formation and function and high levels of aldehydes.’
Mice that lacked this enzyme were found to be far more vulnerable to lung damage from PM2.5. In contrast, when researchers used drugs to boost ALDH1A1 levels, the mice showed significantly improved lung function and better preservation of cilia, even after pollution exposure.
The significance of the work is summed up: ‘as air pollution continues to be a major health concern worldwide, these findings could be key for new treatments that strengthen our respiratory defenses.’
Image: Yasutaka Okabe
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