Three-dimensional ultrastructure of the brain pericyte-endothelial interface

Area of Science:

• Neuroscience
• Cell Biology
• Biophysics

Background:

• Pericytes and endothelial cells are crucial for vascular homeostasis.
• Membranous interdigitations, termed "peg-and-socket" interactions, mediate cell adhesion and biochemical crosstalk.
• The detailed morphology and distribution of these ultrastructures remain largely uncharacterized.

Purpose of the Study:

• To elucidate the morphology and distribution of peg-and-socket interactions between pericytes and endothelial cells in mouse brain capillaries.
• To characterize the 3D architecture of these cellular junctions using advanced microscopy techniques.

Main Methods:

• Application of serial block-face scanning electron microscopy (SBF-SEM) for large-scale 3D ultrastructural analysis.
• High-resolution imaging of mouse brain capillary networks to visualize pericyte-endothelial cell contacts.

Main Results:

• Pericyte-derived pegs exhibited diverse morphologies, including claw-like and bouton shapes.
• Endothelial-derived pegs were less frequent, appearing as columnar protuberances.
• Both pericyte and endothelial pegs were enriched around pericyte cell bodies (somata).
• The ratio of pericyte to endothelial pegs was consistent, but overall peg numbers varied between pericytes.

Conclusions:

• Pericyte somata represent specialized sites for enhanced physical and biochemical interactions with endothelial cells.
• The observed ultrastructural investment highlights the significant communication between these cell types.
• These findings provide critical morphological insights into vascular cell communication and regulation.