Endothelial Cell

Cellula endothelialis

The cells lining cerebral capillaries, sealed by continuous tight junctions and largely stripped of the vesicular transcytosis machinery used by endothelium elsewhere in the body. The structural basis of the blood-brain barrier.

Function

Brain capillary endothelial cells differ from peripheral endothelium in four crucial ways: continuous tight junctions (claudin-5, occludin, JAM-A, ZO-1); vastly reduced transcytosis, enforced by MFSD2A; polarised specific transporters (GLUT1 for glucose, LAT1 for large neutral amino acids, MCT1 for lactate); and ATP-binding cassette efflux pumps (P-glycoprotein/MDR1, BCRP) that extrude lipophilic xenobiotics.

Morphology

Flat, tile-like cells forming the lumen of brain capillaries. Sealed to their neighbors by continuous tight junctions on the apical side.

Specification

  • Receptors: VEGF receptors
  • Location: Cerebral capillaries, except at circumventricular organs (area postrema, median eminence, subfornical organ, OVLT), which lack a BBB to sense blood-borne signals.
  • Firing: Non-spiking
  • Markers: PECAM1/CD31; VWF; KDR/VEGFR2; CLDN5/Claudin-5; OCLN/Occludin; TJP1/ZO-1; SLC2A1/GLUT1; ABCB1/P-gp; MFSD2A
  • Developmental origin: Mesoderm
  • Disease: BBB breakdown is an early and causal event in Alzheimer's disease (pericyte loss precedes cognitive decline), stroke (tight-junction disassembly drives edema), and multiple sclerosis.
  • Cell Ontology: CL:0000115

References

  1. Ben-Zvi A et al. (2014). Mfsd2a is critical for the formation and function of the blood-brain barrier.. Nature 509: 507–511 PMID 24828040
  2. Zlokovic BV (2011). Neurovascular pathways to neurodegeneration in Alzheimer's disease and other disorders.. Nat Rev Neurosci 12: 723–738 PMID 22048062

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