Parkinson’s disease is one of the most common brain disorders in the world, affecting millions of people and causing symptoms that gradually worsen over time.
People with Parkinson’s often experience tremors, stiffness, slow movement, balance problems, and difficulties with everyday tasks. Although current treatments can help control symptoms, there is still no cure, and scientists continue searching for ways to slow or stop the disease itself.
Now, researchers at Stanford Medicine have reported a promising discovery that could open a new path for treatment. In a study carried out in mice, the team found that blocking an overactive enzyme helped restore important communication pathways in the brain and even reversed some early signs of Parkinson’s-related damage.
The research was published in the journal Science Signaling.
The study focused on a form of Parkinson’s disease linked to mutations in a gene called LRRK2. Changes in this gene are among the most common known genetic causes of Parkinson’s disease.
When the mutation is present, an enzyme produced by the gene becomes too active. Scientists believe this excessive activity damages brain cells and interferes with normal brain function.
One of the most important systems affected is the dopamine system. Dopamine is a chemical messenger that allows brain cells to communicate with each other. It plays a major role in controlling movement, motivation, learning, and decision-making.
In Parkinson’s disease, dopamine-producing cells gradually become damaged and die. As dopamine levels fall, symptoms such as tremors, rigidity, and slow movement begin to appear.
Dr. Suzanne Pfeffer, a senior author of the study, explained that reducing the activity of the LRRK2 enzyme may help protect brain cells before severe damage occurs. If treatment can begin early enough, it may be possible to slow or even prevent the progression of symptoms.
To test this idea, the researchers used a compound called MLi-2. This compound attaches to the LRRK2 enzyme and blocks its activity. Scientists have been interested in this type of treatment for several years because it directly targets one of the known causes of disease in people carrying the genetic mutation.
The researchers focused on a part of the brain called the striatum. In a healthy brain, dopamine-producing neurons send signals to this region. These signals help control movement and many other important functions.
For the communication system to work properly, cells rely on tiny structures called primary cilia. These microscopic structures act like antennas, allowing cells to receive and send important messages.
However, when the LRRK2 enzyme becomes overactive, many cells lose their primary cilia. Without these tiny antennas, important signals can no longer be received. This communication breakdown leaves brain cells more vulnerable to damage.
One especially important signal involves a protein known as sonic hedgehog. Despite its unusual name, this protein plays a critical role in helping brain cells survive.
It encourages neighboring cells to produce protective substances that support dopamine-producing neurons. When primary cilia disappear, cells cannot receive the sonic hedgehog signal properly, reducing their ability to protect nearby neurons.
The researchers initially treated mice carrying the Parkinson’s mutation with the inhibitor for two weeks. Unfortunately, the short treatment period produced little improvement. Rather than giving up, the team looked at findings from another study showing that brain cells involved in sleep regularly grow and shrink their primary cilia over time.
This observation inspired them to extend the treatment period. Instead of two weeks, they treated the mice for three months.
The longer treatment produced remarkable results. After three months, the brain cells in the striatum looked much more like those seen in healthy mice. The lost primary cilia had grown back, restoring the cells’ ability to receive important signals. Communication between dopamine-producing neurons and their target cells improved significantly.
The researchers also found evidence that protective responses inside the brain had returned. Even more encouraging, some damaged neurons appeared to be recovering.
These findings suggest that the treatment may do more than simply slow disease progression. It could potentially help repair some of the early damage that has already occurred.
The discovery is especially exciting because Parkinson’s disease often develops silently for many years before obvious symptoms appear. Scientists estimate that early warning signs may emerge up to 15 years before tremors and movement problems begin. These warning signs can include loss of smell, constipation, and certain sleep disorders.
If people with LRRK2 mutations can be identified during these early stages, future treatments that block the overactive enzyme might help delay or prevent the development of more serious symptoms.
The researchers are now exploring whether the same approach could benefit people with other forms of Parkinson’s disease that are not caused by LRRK2 mutations. Several clinical trials of LRRK2 inhibitors are already underway, raising hopes that these findings may eventually lead to new treatment options for patients.
The study was supported by The Michael J. Fox Foundation, the Aligning Science Across Parkinson’s initiative, and the UK Medical Research Council.
While more research is needed before the treatment can be widely used in humans, the results offer new hope. By restoring lost communication pathways and helping damaged brain cells recover, scientists may be moving closer to treatments that not only manage Parkinson’s symptoms but also address some of the underlying causes of the disease.
If you care about Parkinson’s disease, please read studies that Vitamin B may slow down cognitive decline, and Mediterranean diet could help lower risk of Parkinson’s.
For more information about brain health, please see recent studies that blueberry supplements may prevent cognitive decline, and results showing Plant-based diets could protect cognitive health from air pollution.
Copyright © 2026 Knowridge Science Report. All rights reserved.
