Publication Date:
2010-10-15
Description:
The blood-brain barrier (BBB) consists of specific physical barriers, enzymes and transporters, which together maintain the necessary extracellular environment of the central nervous system (CNS). The main physical barrier is found in the CNS endothelial cell, and depends on continuous complexes of tight junctions combined with reduced vesicular transport. Other possible constituents of the BBB include extracellular matrix, astrocytes and pericytes, but the relative contribution of these different components to the BBB remains largely unknown. Here we demonstrate a direct role of pericytes at the BBB in vivo. Using a set of adult viable pericyte-deficient mouse mutants we show that pericyte deficiency increases the permeability of the BBB to water and a range of low-molecular-mass and high-molecular-mass tracers. The increased permeability occurs by endothelial transcytosis, a process that is rapidly arrested by the drug imatinib. Furthermore, we show that pericytes function at the BBB in at least two ways: by regulating BBB-specific gene expression patterns in endothelial cells, and by inducing polarization of astrocyte end-feet surrounding CNS blood vessels. Our results indicate a novel and critical role for pericytes in the integration of endothelial and astrocyte functions at the neurovascular unit, and in the regulation of the BBB.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Armulik, Annika -- Genove, Guillem -- Mae, Maarja -- Nisancioglu, Maya H -- Wallgard, Elisabet -- Niaudet, Colin -- He, Liqun -- Norlin, Jenny -- Lindblom, Per -- Strittmatter, Karin -- Johansson, Bengt R -- Betsholtz, Christer -- England -- Nature. 2010 Nov 25;468(7323):557-61. doi: 10.1038/nature09522. Epub 2010 Oct 13.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Medical Biochemistry and Biophysics, Division of Vascular Biology, Karolinska Institute, Scheeles vag 2, SE-171 77 Stockholm, Sweden. annika.armulik@ki.se〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20944627" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Astrocytes/metabolism
;
Benzamides
;
Blood-Brain Barrier/*cytology/*metabolism
;
Central Nervous System/blood supply
;
Endothelial Cells/metabolism
;
Gene Expression Regulation
;
Imatinib Mesylate
;
Mice
;
Mice, Inbred C57BL
;
Mice, Knockout
;
Pericytes/*metabolism
;
Piperazines/pharmacology
;
Protein Kinase Inhibitors/pharmacology
;
Pyrimidines/pharmacology
;
Transcytosis/drug effects
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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