Scientists Discover New 'Gatekeeper' Cells in Brain's Choroid Plexus
Scientists have discovered a previously unknown cellular barrier in the brain's choroid plexus, named "base barrier cells." The cells form a dynamic seal that can be compromised during systemic inflammation, offering new insights into brain protection and potential therapeutic targets for neurological disorders.
Researchers at the VIB-UGent Center for Inflammation Research and Ghent University have identified a previously unknown cellular barrier in the brain's choroid plexus, a discovery that reshapes understanding of how the brain is protected and how the immune system influences it. The newly identified cells, termed "base barrier cells," were described in a study published in Nature Neuroscience.
The choroid plexus produces cerebrospinal fluid (CSF) and serves as a key interface between the bloodstream and the central nervous system. Using advanced gene sequencing technologies and high-resolution microscopy, the team identified a distinct population of cells located at the base of the choroid plexus. These cells are tightly linked together by tight junctions, described as molecular rivets, forming a sealed boundary that creates a compartmentalized interface between the choroid plexus, CSF, and the brain.
Under healthy conditions, the base barrier cells restrict the movement of even small molecules from the blood-rich core of the choroid plexus into the surrounding CSF and brain tissue. However, during systemic inflammation, such as that caused by a severe infection, the barrier becomes compromised, potentially allowing harmful substances and cells to enter the central nervous system. This offers a new mechanistic explanation for how peripheral immune activation may impact the brain.
The researchers found that the base barrier cells emerge early in brain development and persist throughout life. Importantly, they confirmed the cells are present in both mouse and human brain tissue, strengthening the translational relevance of the findings.
The discovery challenges the traditional view that the blood-brain barrier is the primary protective structure, suggesting instead that the brain is safeguarded by a more complex, layered system of defenses. The findings may have implications for understanding neuroinflammation and neurological conditions, and could open new therapeutic strategies aimed at strengthening this gatekeeper barrier. In a precision medicine context, the barrier could serve as both a biomarker of vulnerability and a therapeutic target.