Summary: For years, accumulation of the tau protein has been recognized as a central feature of Alzheimer’s disease. New research reveals how the brain clears tau: specialized non-neuronal cells called tanycytes act as a waste-shuttle, capturing toxic tau from the cerebrospinal fluid (CSF) and transferring it into the bloodstream for removal.
The study shows that in Alzheimer’s patients, tanycytes become fragmented and lose their shuttle function, impairing tau clearance and allowing toxic protein to build up. This shifts attention from neurons to these structural support cells as a promising target for slowing neurodegeneration.
Key Facts
- The tanycyte shuttle: Tanycytes are concentrated around the brain’s third ventricle and move metabolic signals and waste between the cerebrospinal fluid and the blood.
- Degeneration in humans: Tissue from Alzheimer’s patients showed tanycytes with fragmented processes and altered gene expression compared with healthy brains.
- Tau clearance: Rodent and cellular models demonstrated that healthy tanycytes actively take up tau from CSF and help transport it to the circulation.
- Homeostasis hub: Tanycytes act as an interface between brain and body, supporting the balance of signaling and clearance needed for cognitive health.
- Potential intervention: Protecting tanycyte integrity may restore the brain’s natural clearance pathways and slow Alzheimer’s progression.
Source: Cell Press
Tau accumulation in the brain is a hallmark of Alzheimer’s disease.
A paper published March 5 in the Cell Press journal Cell Press Blue describes a previously unrecognized mechanism that appears to permit tau buildup. Using animal and cell models together with patient tissue, the researchers identify tanycytes—specialized cells that coordinate brain-body signaling—as central to tau transport and clearance.
“Our results reveal a previously underappreciated, disease-relevant role for tanycytes in neurodegeneration,” says corresponding author Vincent Prevot of INSERM in France. “Preserving tanycyte health could improve tau clearance and help limit disease progression.”
Tanycytes are non-neuronal cells located mainly around the brain’s third ventricle. Earlier work showed they shuttle metabolic and hormonal signals between blood and cerebrospinal fluid (CSF), the fluid that surrounds the brain and spinal cord and helps maintain brain homeostasis.
In this study, the team investigated how tanycytes handle toxic molecules such as tau. They found that tanycytes take up tau from the CSF and hand it off to the blood for disposal. When tanycyte function is compromised, tau clearance is reduced and toxic protein accumulates in the brain.
“Using rodent and cellular models, we demonstrated that tanycytes actively remove tau,” Prevot explains. “We also observed that tanycytes in brains from human Alzheimer’s patients were structurally fragmented and showed gene-expression changes connected to their shuttle role.”
The authors emphasize that these results support the idea of preserving brain homeostasis as a strategy to prevent neurodegeneration. They also acknowledge important challenges: the lack of ideal animal models for Alzheimer’s disease and the need for larger, longitudinal human studies to establish causality and clarify the timeline linking tanycyte dysfunction to tau pathology.
“This work provides the first evidence of structural and functional alterations in these little-known but important brain cells in human disease,” Prevot adds.
Funding:
This research was supported by the European Research Council, the National Institutes of Health, the Fondation pour la Recherche Médicale, and the Fondation NRJ for Neuroscience–Institut de France.
Key Questions Answered:
A: Tanycytes are specialized cells that line parts of the brain’s ventricles. They act like shuttle buses: taking up molecules from the fluid around the brain and conveying them across the brain–blood interface into the circulation.
A: The study found that tanycytes in Alzheimer’s patients display fragmentation of their processes and changes in gene expression, especially in genes related to vesicular transport. This structural and molecular damage reduces their ability to move tau out of the CSF, allowing it to accumulate.
A: Restoring or maintaining tanycyte function is a potential therapeutic goal. Protecting these cells’ structure and transport mechanisms could support the brain’s natural clearance system and may slow disease progression, but further research is needed to develop and test interventions.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full.
- Additional context was provided by staff.
About this Alzheimer’s disease research news
Author: Julia Grimmett
Source: Cell Press
Contact: Julia Grimmett – Cell Press
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Tanycytic degeneration impairs tau clearance and contributes to Alzheimer’s disease pathology” by Florent Sauvé, Ricardo Martinez-Gómez, Yvon Mbouamboua, Gaëtan Ternier, Sreekala Nampoothiri, Elian Dupré, Lolie Garcia, Marie Couralet, Julie Dewisme, Thibaud Lebouvier, Clément Danis, S. Rasika, Marc Dhenain, Young-Bum Kim, Philippe Ciofi, Luc Buée, Isabelle Landrieu, Florence Pasquier, Matthieu Lilamand, Claire Paquet, Paolo Giacobini, Pascal Barbry, Claude-Alain Maurage, Ruben Nogueiras, Markus Schwaninger, and Vincent Prevot. Cell Press Blue
DOI: 10.1016/j.cpblue.2026.100003
Abstract
Tanycytic degeneration impairs tau clearance and contributes to Alzheimer’s disease pathology
Alzheimer’s disease (AD) is marked by abnormal accumulation of tau protein in the brain and cerebrospinal fluid rather than timely removal into the blood. The mechanisms underlying this impaired efflux are not well understood.
Using animal and cellular models alongside patient tissues, the study shows that tanycytes in the hypothalamic median eminence—which connect CSF and blood—participate in tau transport and in AD pathogenesis. In mice, tanycytes take up tau from the CSF and release it into pituitary portal capillaries, enabling its entry into the systemic circulation.
Disrupting tanycytic vesicular transport reduces CSF-to-blood tau efflux and exacerbates tau pathology. In Alzheimer’s patients, plasma-to-CSF ratios of total and p181 tau are lower than expected.
Postmortem analysis of tanycytes from AD brains revealed severely fragmented processes and significant transcriptomic changes identified by single-nucleus RNA sequencing, particularly affecting genes involved in vesicular transport—providing a molecular explanation for reduced clearance.
These findings that link tanycytic dysfunction to human disease and demonstrate a brain-to-blood tanycytic shuttle have broad implications for understanding and potentially treating Alzheimer’s disease.