Every year, nearly seven million people die early because of air pollution.
It is well known that breathing in polluted air can cause lung problems and heart disease, but scientists are now discovering that it can also harm the brain.
Recent research suggests that pollution from wildfires, cars, and even processed meats may increase the risk of brain diseases like Alzheimer’s and autism.
Scientists at Scripps Research have found that a specific chemical change in the brain may be responsible for this damage.
This chemical reaction, called S-nitrosylation, can be triggered by inflammation, aging, and toxins from air pollution, pesticides, and processed foods.
When this reaction occurs, brain cells struggle to make new connections, which eventually leads to their death. The researchers believe this could be a major factor in memory loss and other neurological diseases.
The study, published on February 27, 2025, in the Proceedings of the National Academy of Sciences, showed promising results. When scientists blocked S-nitrosylation in a key brain protein, some memory loss was reversed in mice with Alzheimer’s. They also saw improvements in nerve cells grown from human stem cells.
Dr. Stuart Lipton, a senior researcher and professor at Scripps Research, has spent years studying this process. He explains that this discovery reveals how air pollutants can contribute to memory loss and brain diseases.
If scientists can find a way to stop this harmful chemical reaction, they might be able to develop new treatments for Alzheimer’s and other brain disorders.
S-nitrosylation is not a new discovery. Over 20 years ago, Dr. Lipton found that a molecule called nitric oxide (NO) binds to proteins in the brain, changing their function. While NO is a normal part of the body’s processes, high levels can be harmful.
These high levels can be caused by pollution, smoke from wildfires, pesticides, and even certain foods. When too much NO is present, it triggers excessive S-nitrosylation, which disrupts brain function.
Previous studies have already linked this chemical process to diseases like autism, Parkinson’s, and some cancers. In this latest research, the team focused on how it affects a protein called CRTC1. This protein helps regulate genes that allow brain cells to connect with each other, a process that is crucial for learning and memory.
The scientists tested their theory in both mouse and human brain cells. First, they confirmed that too much NO leads to S-nitrosylation of CRTC1. When this happens, CRTC1 cannot bind to another important brain protein called CREB. This failure stops genes from being activated, which weakens the connections between neurons.
They also found high levels of this harmful chemical reaction in Alzheimer’s patients and in mice with the disease. This suggests that S-nitrosylation might play a key role in how the disease develops.
To test whether stopping this reaction could improve brain function, the scientists engineered a version of CRTC1 that could not undergo S-nitrosylation. When they introduced this modified protein into brain cells from Alzheimer’s patients, the cells survived longer and maintained their connections.
In mice with Alzheimer’s, the re-engineered CRTC1 helped restore memory-related genes and improved brain function. Dr. Lipton explains that nearly all the molecular pathways involved in forming new memories were rescued. This suggests that preventing this chemical reaction could lead to new treatments for Alzheimer’s and other neurological conditions.
One of the most important findings in this study is how environmental toxins might speed up brain aging and contribute to diseases like Alzheimer’s. Pollution from cars and wildfires can increase NO levels in the brain, which in turn triggers S-nitrosylation.
If this chemical reaction damages brain cells over time, it could explain why people exposed to high levels of pollution may be at greater risk for memory problems as they age.
Even without pollution, aging itself increases inflammation and NO levels in the body. At the same time, the body’s natural defenses weaken, making proteins more vulnerable to harmful changes. This might help explain why the risk of Alzheimer’s rises as people get older.
While this study is promising, it is just the beginning. Dr. Lipton and his team are now working to develop drugs that can block specific S-nitrosylation reactions, including those affecting CRTC1. If successful, these drugs could help slow or even prevent memory loss in people at risk for Alzheimer’s.
This research provides new hope for understanding and treating Alzheimer’s and other brain diseases. It also highlights the urgent need to reduce pollution and environmental toxins that may be harming our brains. While scientists continue to explore new treatments, reducing exposure to air pollution and maintaining a healthy lifestyle may help protect brain health as we age.
The research findings can be found in PNAS.
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