Alzheimer’s and Parkinson’s disease are the two most common brain disorders that slowly get worse over time.
They affect millions of people around the world. Although they cause different symptoms—like memory loss in Alzheimer’s and movement problems in Parkinson’s—new research suggests they may share a similar cause in the brain.
Scientists from the Okinawa Institute of Science and Technology (OIST) recently published a study in the Journal of Neuroscience that reveals how both diseases disrupt communication between brain cells.
They found that the same chain reaction of problems in the brain may be behind both conditions.
The brain works by sending signals between cells using chemicals called neurotransmitters. These chemicals are stored in small packages called synaptic vesicles.
The vesicles carry neurotransmitters to the edge of the cell, release them to send a signal, and then get recycled for the next signal. This process happens constantly to keep the brain working properly.
In this study, the researchers found that in both Alzheimer’s and Parkinson’s, this vesicle recycling system is damaged. They discovered that harmful proteins that build up in brain cells cause the overproduction of structures called microtubules. Normally, microtubules help keep cells in shape and transport materials.
But when there are too many of them, they trap another protein called dynamin. Dynamin plays a key role in recycling vesicles. Without enough dynamin, the vesicles don’t get reused properly, and communication between brain cells breaks down.
Dr. Dimitar Dimitrov, one of the authors, explained that synapses—where brain cells communicate—are involved in different brain functions. So, when these synapses are damaged in memory-related areas, people may develop Alzheimer’s symptoms.
When the damage happens in areas that control movement, it may lead to Parkinson’s symptoms. This helps explain why both diseases may start with different symptoms but share a common problem in how brain cells communicate.
This discovery could lead to new treatments. The research team identified three different steps in this chain of problems that could be targeted with medicine: stopping the buildup of harmful proteins, preventing the overgrowth of microtubules, or stopping microtubules from trapping dynamin.
Professor Tomoyuki Takahashi, another author of the study, said this kind of research is important because it gives scientists and doctors new ways to think about how to treat these difficult brain diseases.
This study builds on years of work by the same team. They have previously shown how microtubules are involved in Parkinson’s and how dynamin gets stuck in Alzheimer’s. In 2024, they even discovered a small molecule that reversed symptoms of Alzheimer’s in mice. Now, they believe this same molecule might also help people with Parkinson’s disease.
In conclusion, this new research shows that even though Alzheimer’s and Parkinson’s seem different on the surface, they may share a common problem inside the brain. The way brain cells stop communicating properly may be the root cause of both diseases.
With this new understanding, scientists hope to find new treatments that help people with either condition, improving their lives and easing the burden on families and society.
If you care about Alzheimer’s, please read studies about Scientists find the root cause of Alzheimer’s disease and findings of Alzheimer’s might not be primarily a brain disease. A new theory suggests it’s an autoimmune condition.
If you care about Alzheimer’s disease, please read studies about These places in U.S. have the most cases of Alzheimer’s disease and findings of Scientists confirm the link between COVID-19 and Alzheimer’s disease.
The study is published in The Journal of Neuroscience.
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