Dynamic protein behavior drives blood-brain barrier specialization, study reveals
· Medical Xpressby Institute for Bioengineering of Catalonia
edited by Gaby Clark, reviewed by Robert Egan
Gaby Clark
Scientific Editor
Meet our editorial team
Behind our editorial process
Robert Egan
Senior Editor
Meet our editorial team
Behind our editorial process Editors' notes
This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility:
fact-checked
peer-reviewed publication
trusted source
proofread
The GIST Add as preferred source
A study led by researchers at the Institute for Bioengineering of Catalonia (IBEC), in collaboration with the Proteomics Platform of the Institute for Research in Biomedicine (IRB Barcelona), has uncovered a key mechanism that helps define how the blood-brain barrier functions—not just based on which proteins are present, but on how dynamically they are used.
The research, published in iScience, shows that brain endothelial cells, which form the BBB, possess a unique "endocytic profile," describing how quickly proteins are internalized, recycled or degraded. In other words, it describes how long they remain active at the cell surface. This property, known as the endocytic turnover rate (ETOR), emerges as a critical driver of blood-brain barrier specialization and is disrupted under inflammatory conditions.
"Through a collaboration bringing together cell biology, proteomics, bioinformatics and mathematics, we asked whether blood-brain barrier specialization arises not only from the proteins it expresses, but also from how it uses them," says Daniel Gonzalez-Carter, senior research fellow in the Molecular Bionics Group at IBEC and leader of the study.
"These findings may help identify novel therapeutic strategies to restore neurovascular health," adds Giuseppe Battaglia, ICREA research professor at IBEC, principal investigator at the Molecular Bionics Group and co-author of the study.
The blood-brain barrier is a highly selective interface that protects the brain while allowing essential nutrients and signals to pass. Traditionally, its function has been explained by the identity and abundance of proteins on the surface of endothelial cells.
However, it remains unclear whether the dynamic regulation of these proteins, the so-called ETOR profile, contributes to the unique properties of brain endothelial cells. It is also unknown whether this dynamic regulation changes in disease in ways that affect the blood-brain barrier.
Using advanced proteomics, the team tracked how nearly 1,000 membrane proteins behave over time in rat endothelial cells from the brain and other organs. They found that how long proteins remain on the cell surface provides an additional, independent layer of regulation.
The researchers identified a distinct ETOR profile in brain endothelial cells that clearly differentiates them from endothelial cells in other organs, even when protein composition is relatively similar.
More specifically, proteins involved in transport showed high turnover rates, which likely support efficient nutrient delivery to the brain. In contrast, junction proteins, essential for maintaining the barrier's tightness, displayed low turnover, ensuring structural stability.
Crucially, these dynamics were not correlated with protein abundance, demonstrating that ETOR represents an independent regulatory feature of endothelial function.
Inflammation rewires barrier behavior
The research also shows that pathology alters these dynamics. When exposed to inflammatory signals, brain endothelial cells retained a similar overall protein composition, but their behavior changed: Their ETOR profile was significantly altered.
"We found that brain endothelial cells handle proteins in a very specific way that sets them apart from blood vessels in the rest of the body. Importantly, this specialized behavior is disrupted during inflammation, making them behave more like typical peripheral blood vessels and potentially weakening their ability to protect the brain," Gonzalez-Carter explains.
Importantly, the researchers found that changes in protein abundance primarily reflected immune responses. In contrast, changes in ETOR revealed processes linked to vascular remodeling. This suggests that focusing only on protein levels may overlook key disease mechanisms.
Implications for brain health and therapy
The findings open new avenues for understanding how the BBB is regulated in health and disease. Since the barrier plays a central role in neurological disorders—including Alzheimer's disease, the consequences of stroke and neuroinflammation, among others—identifying the mechanisms that control its integrity is crucial.
By highlighting ETOR as a key regulatory dimension, the study could also inform strategies to restore BBB function, improve drug delivery to the brain, and identify new therapeutic targets to protect or restore brain health.
Publication details
Alba Tomás-Sitjes et al, Endocytic turnover of endothelial cell-membrane proteins as a driver of rat blood-brain barrier specialization and dysfunction, iScience (2026). DOI: 10.1016/j.isci.2026.116231
Journal information: iScience
Key medical concepts
Clinical categories
Neurology Provided by Institute for Bioengineering of Catalonia Who's behind this story?
Gaby Clark
MA in English, copy editor since 2021 with experience in higher education and health content. Dedicated to trustworthy science news. Full profile →
Robert Egan
Bachelor's in mathematical biology, Master's in creative writing. Well-traveled with unique perspectives on science and language. Full profile →
Citation: Dynamic protein behavior drives blood-brain barrier specialization, study reveals (2026, July 2) retrieved 2 July 2026 from https://medicalxpress.com/news/2026-07-dynamic-protein-behavior-blood-brain.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.