title: Tyrosine phosphatase inhibition induces loss of blood-brain barrier integrity by matrix metalloproteinase-dependent and -independent pathways.
abstract: Tight junctions between endothelial cells of brain capillaries form the structural basis of the blood-brain barrier (BBB), which controls the exchange of molecules between blood and CNS. Regulation of cellular barrier permeability is a vital and complex process involving intracellular signalling and rearrangement of tight junction proteins. We have analysed the impact of tyrosine phosphatase inhibition on tight junction proteins and endothelial barrier integrity in a primary cell culture model based on porcine brain capillary endothelial cells (PBCEC) that closely mimics the BBB in vitro. The tyrosine phosphatase inhibitor phenylarsine oxide (PAO) induced increased matrix metalloproteinase (MMP) activity, which was paralleled by severe disruption of cell-cell contacts and proteolysis of the tight junction protein occludin. ZO-1 and claudin-5 were not affected. Under these conditions, the transendothelial electrical resistance (TEER) was markedly reduced. PAO-induced occludin proteolysis could be prevented by different MMP inhibitors. Pervanadate (PV) reduced the TEER similar to PAO, but did not increase MMP activity. Cell-cell contacts of PV-treated cells appeared unaffected, and occludin proteolysis did not occur. Our results suggest that tyrosine phosphatase inhibition can influence barrier properties independent of, but also correlated to MMPs. Evidence is given for a role of MMPs in endothelial tight junction regulation at the BBB in particular and probably at tight junctions (TJs) in general.
authors.affiliation: Institut fuer Biochemie, Westfaelische Wilhelms-Universitaet Muenster, Wilhelm-Klemm-Str. 2, 48149, Münster, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Lohmann
authors.forename: Miriam
authors.initials: M
authors.lastname: Krischke
authors.forename: Joachim
authors.initials: J
authors.lastname: Wegener
authors.forename: Hans Joachim
authors.initials: HJ
authors.lastname: Galla
mesh_terms: D000818:Animals; D001152:Arsenicals / Q000494:pharmacology; D001812:Blood-Brain Barrier / Q000502:physiology*; D015153:Blotting, Western; D001921:Brain / Q000502:physiology; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D017097:Electric Impedance; D004586:Electrophoresis; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D004730:Endothelium, Vascular / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007150:Immunohistochemistry; D020782:Matrix Metalloproteinases / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D013552:Swine; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism*; D014638:Vanadates / Q000494:pharmacology
chemical_list: D001152:Arsenicals; D004791:Enzyme Inhibitors; C076715:pervanadate; C029341:oxophenylarsine; D014638:Vanadates; D017027:Protein Tyrosine Phosphatases; D020782:Matrix Metalloproteinases