The accumulation of tau protein in the brain is a defining feature of Alzheimer’s disease. In a study published March 5 in the Cell Press journal Cell Press Blue, researchers describe a newly identified biological process that may help explain how tau builds up. The research combined animal experiments, cell studies, and analyses of tissue from patients. The findings point to an important role for tanycytes, specialized brain cells that help regulate communication between the brain and the rest of the body.
“Our findings reveal a previously underappreciated, disease-relevant role for tanycytes in neurodegeneration,” says corresponding author Vincent Prevot of INSERM in France. “Focusing on tanycyte health could be a way to improve tau clearance and limit disease progression.”
What Are Tanycytes?
Tanycytes are non-neuronal brain cells that are mainly located in the third ventricle of the brain. Earlier studies have shown that they help move metabolic signals between the bloodstream and the cerebrospinal fluid (CSF). This fluid surrounds the brain and spinal cord and acts as a communication network that helps maintain the body’s internal balance.
How Tanycytes Help Remove Toxic Tau
In the new study, the scientists investigated how tanycytes help eliminate harmful molecules such as tau to support brain health. Their results show that these cells transport toxic substances from the CSF into the bloodstream, where they can be cleared from the body. When this transport system fails to work properly, tau can begin to accumulate in the brain.
“Surprisingly, we were able to show in rodent and cellular models not only that tanycytes were indeed involved in clearing tau but also that tanycytes in the brains of human Alzheimer’s patients were fragmented and had changes in gene expression related to this shuttle function,” Prevot says.
Potential Implications for Alzheimer’s Treatment
The researchers say their findings suggest that protecting the brain’s internal balance could help slow neurodegeneration. At the same time, they caution that developing treatments aimed at tanycytes will require overcoming several challenges.
One obstacle is the lack of reliable animal models that fully replicate Alzheimer’s disease. Another challenge is the need for larger patient groups and long term studies to determine cause and effect and to clarify how dysfunction in tanycytes may lead to tau buildup.
“Our findings provide the first evidence for structural and functional alterations in these little-known but key brain cells in human disease,” says Prevot.
This work was supported by the European Research Council, National Institutes of Health, the Fondation pour la Recherche Médicale, and the Fondation NRJ for Neuroscience-Institut de France.
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