Genetic Variants in Oxidative Stress Genes Explain Why Air Pollution Hits Some Asthma Patients Harder Than Others
Key Insights
A University of Pittsburgh study identified seven oxidative stress-related genes whose variants influence how PM2.5 (search) air pollution affects lung function in adults with asthma (search).
For every 1 μg/m³ increase in PM2.5 (search) exposure, participants' lung function declined by an average of 0.7% as measured by FEV1.
Variants in genes including OXSR1 (search), PXDN (search), and TPO (search) were linked to disproportionately worse lung function, with some reducing protective RNA responses and others amplifying damaging ones.
For many people with asthma (search), air-quality advisories signal worsening symptoms. Yet the extent to which pollution exacerbates the condition has long varied dramatically from person to person—a puzzle that science has struggled to solve. Now, a landmark study from the University of Pittsburgh School of Public Health (search), published in eBioMedicine, has identified the biological pathways that begin to explain this variability, revealing how air-pollution exposure interacts with an individual's genetic makeup.
The research, conducted in collaboration with the Severe Asthma Research Program (search) (SARP), is among the largest and most comprehensive of its kind to date. It analyzed data from nearly 1,000 adults with asthma (search) across the United States, combining whole genome sequencing, air pollution exposure data, and gene-expression profiling.
How Genetics Shapes the Response to PM2.5 (search)
The team focused on approximately 450 genes that control oxidative stress—a process in which highly reactive molecules damage cells and tissues. "Those stresses on cells can translate into serious physiologic effects, like worsening lung function or asthma (search) exacerbations," said Sally Wenzel, M.D., corresponding author, chair of Pitt Public Health's Department of Environmental and Occupational Health and director of Pitt's Asthma and Environmental Lung Health Institute at UPMC, who co-led the study with Shuangjia Xue, a recent graduate of the department's Ph.D. program.
The researchers examined how these genes interacted with exposure to fine particulate matter known as PM2.5 (search)—microscopic particles with a diameter less than 2.5 microns, small enough to penetrate deep into the lungs and widely considered one of the most harmful components of air pollution.
The study found a clear dose-response relationship: for every 1 μg/m³ increase in PM2.5 (search) exposure, participants' lung function fell by an average of 0.7%, as measured by FEV1, a standard breathing test. "In these individuals who were living with asthma (search), the higher their exposure to this particulate matter, the lower their lung function overall," Wenzel noted, emphasizing that the study focused on people already living with asthma rather than those in the process of developing the disease.
Uncovering Key Genetic Variants
The researchers examined more than 4,300 genetic variants across 120 genes involved in the body's oxidative stress response. They identified 20 genetic variants in seven genes that appeared to influence how strongly air pollution affected lung function. In some people, these variants were linked to a steeper decline in breathing ability under higher pollution levels; in others, certain variants appeared to offer some protection.
Notably, the study was the first of its kind to use human airway samples in an analysis of gene transcription—how DNA is converted into RNA, which in turn directs cells to produce proteins. "Genes lay out who we could be, but the RNA, and the proteins they transcribe, are what make us who we are," Wenzel said. Airway epithelial cell samples were collected through bronchial brushings in a subset of about 200 study participants, revealing how gene activity changed in response to pollution exposure.
The most vulnerable patients carried variants in seven oxidative stress-related genes that shape how the body responds to cellular damage from pollution. Individuals with less common variants in two specific genes, OXSR1 (search) and PXDN (search), had disproportionately worse lung function due to lower protective RNA responses to pollution. Those with a specific variant in another gene, TPO (search), also had worse lung function, but for them, it was due to stronger RNA responses—suggesting that both underactive and overactive gene responses can contribute to vulnerability.
Toward Precision Medicine and Public Health
The molecular pathways described in the study could point to targets for new therapies and open the door to much more. "You could imagine a simple test for a panel of genes that could be used to flag someone as highly susceptible to the effects of pollution," said Wenzel. Such an approach could enable both precision medicine—tailoring care to an individual—and precision public health—targeting interventions to specific populations most likely to benefit.
The team's next steps include digging deeper into the pathways identified in this study and testing whether targeted interventions, ranging from behavioral changes to targeted anti-oxidant therapies, can blunt the harmful effects of pollution in high-risk individuals. "We're already exploring some of these pathways," Wenzel said. "Ultimately, while reducing the amount of pollution remains the most effective approach, the findings from our study suggest we could develop interventions specific to at-risk people that would lessen the impact of pollution."