Researchers at Johns Hopkins Medicine have discovered microscopic nanotube channels in the brain that neurons use to transfer toxic molecules, potentially spreading harmful proteins linked to Alzheimer’s disease. The findings, based on experiments with genetically modified mice, suggest these structures increase early in disease models. The study offers new insights into neurodegenerative disorders and possible therapeutic targets.
Scientists at Johns Hopkins Medicine have uncovered how mammalian brains form intricate networks of tiny tubes, called dendritic nanotubes, to move toxins in and out of neurons, similar to pneumatic tubes in factories. These nanotubes primarily help expel toxic small molecules, such as amyloid-beta, which can form sticky plaques characteristic of Alzheimer’s disease.
The research, published on October 2, 2025, in Science, utilized genetically modified mice and advanced imaging tools, funded by the National Institutes of Health. By observing brain tissue samples with high-resolution microscopy and live-cell imaging, the team watched neurons extend long, slender connections between dendrites to shuttle materials.
"Cells have to get rid of toxic molecules, and by producing a nanotube, they can then transmit this toxic molecule to a neighbor cell," said corresponding author Hyungbae Kwon, associate professor of neuroscience at Johns Hopkins University School of Medicine. "Unfortunately, this also results in spreading harmful proteins to other areas of the brain."
In mice engineered to develop Alzheimer’s-like amyloid buildup, the number of nanotubes increased at three months old—when symptoms were absent—compared to healthy mice of the same age. By six months, nanotube counts equalized between the groups. Similar nanotube structures were identified in human neurons from a public electron microscopy database.
"The long and thin column-like structures of these dendritic nanotubes help transfer information quickly from neuron to neuron," Kwon added. The team plans future experiments to explore nanotube networks in other brain cell types and manipulate their formation for potential treatments. "When designing a potential treatment based on this work, we can target how nanotubes are produced—by either increasing or decreasing their formation—according to the stage of the disease," Kwon noted.
Additional contributors include Minhyeok Chang, Sarah Krüssel, Juhyun Kim, Daniel Lee, Alec Merodio, and Jaeyoung Kwon from Johns Hopkins, as well as Laxmi Kumar Parajuli and Shigeo Okabe from the University of Tokyo.