title: Effects of the chemokine CCL2 on blood-brain barrier permeability during ischemia-reperfusion injury.
abstract: The chemokine CCL2 is considered as one of the main effectors driving postischemic infiltration of monocytes into the brain parenchyma. New experimental data, however, suggest that CCL2 could also participate in blood-brain barrier (BBB) 'opening' during the transmigration of monocytes. The current study examines the role of CCL2 in regulating BBB permeability after ischemia in vitro. To address this issue, an in vitro BBB model (coculture of astrocytes and brain endothelial cells) was subjected to 5 h of oxygen glucose deprivation, followed by reoxgenation (in vitro ischemia/reperfusion (I/R)) for 0 to 48 h. During reperfusion, there was a biphasic enhancement of barrier permeability, with a 200-fold increase in barrier permeability to FITC-albumin at 6 h and a further period of disruption around 24 h. The latter coincided with increased secretion of CCL2 by both astrocytes and brain endothelial cells and increased levels of the CCL2 receptor, CCR2. Applying antisense oligonucleotide or neutralizing antibody to block CCL2 significantly decreased I/R-induced enhancement of BBB permeability (approximately twofold) and redistribution of tight-junction (TJ) proteins (occludin, zonula occluden-1, 2, claudin-5). Similarly, absence of CCR2 from endothelial cells caused stabilization of TJ complexes and decreased the permeability of brain endothelial barrier during in vitro I/R. These data suggest CCL2/CCR2 has an important role in regulating brain endothelial permeability and might be a potential novel therapeutic target for stroke.
authors.affiliation: Department of Neurosurgery, University of Michigan Medical School, Ann Arbor, Michigan 48109-0532, USA.
authors.forename: Oliver B
authors.initials: OB
authors.lastname: Dimitrijevic
authors.forename: Svetlana M
authors.initials: SM
authors.lastname: Stamatovic
authors.forename: Richard F
authors.initials: RF
authors.lastname: Keep
authors.forename: Anuska V
authors.initials: AV
authors.lastname: Andjelkovic
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001812:Blood-Brain Barrier / Q000378:metabolism*; D015153:Blotting, Western; D002199:Capillary Permeability / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000378:metabolism*; D018920:Coculture Techniques; D017097:Electric Impedance; D042783:Endothelial Cells / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005455:Fluorescent Antibody Technique; D051379:Mice; D054390:Receptors, CCR2; D019707:Receptors, Chemokine / Q000378:metabolism; D015427:Reperfusion Injury / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: C491768:Ccl2 protein, mouse; C515335:Ccr2 protein, mouse; D018932:Chemokine CCL2; D054390:Receptors, CCR2; D019707:Receptors, Chemokine