Researchers at Johns Hopkins Medicine have uncovered how mammalian brains create networks of nanotubes that shuttle toxins in and out of brain cells — a process similar to pneumatic tubes used in factories and stores. Their groundbreaking experiments, conducted on genetically engineered mice with specialized imaging technology, were funded by the National Institutes of Health and published on October 2 in Science.
This discovery could significantly advance understanding of Alzheimer’s disease and other neurodegenerative disorders, offering new pathways for potential treatment strategies.
Nanotubes: The Brain’s Hidden Transport System
As reported by John Hopkins Medicine Press release, the team observed that neurons form microscopic tubular connections, or nanotubes, to eliminate toxic small molecules such as amyloid-beta — a sticky protein associated with Alzheimer’s.
“Cells have to get rid of toxic molecules, and by producing a nanotube, they can transmit this molecule to a neighboring cell,” explained Dr. Hyungbae Kwon, corresponding author and associate professor of neuroscience at the Johns Hopkins University School of Medicine. “Unfortunately, this also spreads harmful proteins to other areas of the brain.”
How Dendritic Nanotubes Work
Using high-powered microscopes and live cell imaging, the researchers observed how neurons produce finger-like protrusions called dendritic nanotubes between their dendrites—the arm-like extensions of brain cells. These nanotubes act as microscopic channels, ferrying calcium, ions, and toxic molecules rapidly from one cell to another.
“The long, column-like structures of these nanotubes enable fast communication between neurons,” said Dr. Kwon. “They are ideal for transferring materials across distant brain cells.”
Simulating Alzheimer’s-Like Processes
Through computational modeling, the team found that this nanotube-mediated process resembles early amyloidosis, a precursor to Alzheimer’s disease. The models revealed a previously unknown layer of brain connectivity, expanding current understanding of how neurons interact beyond traditional synaptic communication.
To validate these findings, researchers compared brain tissue samples from normal mice and those genetically engineered to develop amyloid buildup, the hallmark of Alzheimer’s. Remarkably, Alzheimer’s-model mice had more nanotubes at three months of age—before any symptoms appeared—than normal mice of the same age. By six months, nanotube levels in both groups began to equalize, suggesting that nanotube formation may precede visible disease symptoms.
Nanotubes Also Found in Human Brain Samples
To confirm whether similar mechanisms exist in humans, scientists analyzed publicly available human neuron data using electron microscopy. They identified nanotubes forming between neurons in a pattern comparable to those seen in mice, reinforcing the biological relevance of the discovery.
Implications for Future Treatments
Dr. Kwon and his team plan to investigate whether these nanotube networks exist in other brain cell types, beyond neurons. The next phase of research will explore whether controlling nanotube formation—either enhancing or suppressing it—can influence brain health.
“When designing a potential treatment based on this work, we can target how nanotubes are produced,” Kwon noted. “By either increasing or decreasing their formation depending on the stage of the disease, we may one day protect the brain from degeneration.”
A Step Toward Novel Alzheimer’s Therapies
This pioneering study provides crucial insight into the hidden communication systems of the brain and how they may contribute to the spread of toxic proteins in Alzheimer’s and related conditions. By understanding and eventually manipulating this nanotube network, scientists move a step closer to developing targeted therapies that could prevent or slow neurodegeneration.