Base barrier cells provide compartmentalization of choroid plexus, brain and CSF

Area of Science:

• Neuroscience
• Cell Biology
• Developmental Biology

Background:

• The choroid plexus (ChP) produces cerebrospinal fluid (CSF) and forms the blood-CSF barrier.
• Unique fibroblasts, termed choroid plexus base barrier cells (BBCs), exist at ChP-brain attachment sites.

Purpose of the Study:

• To identify and characterize the novel BBCs.
• To investigate the origin, function, and conservation of BBCs.
• To determine the role of BBCs in central nervous system (CNS) protection and inflammatory responses.

Main Methods:

• Transcriptional profiling to compare BBCs with other cell types.
• Immunohistochemistry and electron microscopy to examine cell junctions and structure.
• In vivo studies to observe BBC behavior during development and inflammation.

Main Results:

• BBCs originate from meningeal mesenchymal precursors and are conserved across species.
• BBCs exhibit transcriptional similarity to meningeal arachnoid barrier cells and possess adherens and tight junctions.
• BBCs function as a barrier, regulating CNS communication and integrity, with integrity loss observed during inflammation.

Conclusions:

• A novel barrier formed by BBCs exists at the choroid plexus base.
• This barrier is critical for compartmentalizing the ChP stroma, brain parenchyma, and CSF, thereby protecting the CNS.
• BBCs play a vital role in maintaining CNS homeostasis and regulating immune cell infiltration.