title: Cytokine-mediated dysregulation of zonula occludens-1 properties in human brain microvascular endothelium.
abstract: Zonula occludens-1 (ZO-1) is essential to the proper assembly of interendothelial junction complexes that control blood-brain barrier (BBB) integrity. The goal of the current paper was to improve our understanding of how proinflammatory cytokines modulate ZO-1 properties within the human BBB microvascular endothelium. In this respect, we investigated the effects of TNF-α and IL-6 on ZO-1 using human brain microvascular endothelial cells (HBMvECs). Following treatment of HBMvECs with either cytokine (0-100 ng/ml, 18 h), we observed significantly decreased ZO-1 expression and ZO-1:occludin co-association, in parallel with increased ZO-1 phosphorylation (pTyr and pThr). All effects were dose-dependent. Either cytokine also caused extensive cell-cell border delocalization of ZO-1 in parallel with elevated HBMvEC permeability. Furthermore, pre-treatment of HBMvECs with antioxidants (superoxide dismutase, catalase, apocynin, N-acetylcysteine), or employing targeted inhibition of NADPH oxidase activation (NSC23766, gp91/p47 siRNA), were all found to comparably attenuate the cytokine-dependent decrease in ZO-1 protein expression. In summary, we present an in vitro model of how different proinflammatory cytokines can dysregulate ZO-1 properties in HBMvECs. A causal role for NADPH oxidase activation and oxidant signalling is also confirmed. Our findings add mechanistic depth to current in vivo models of BBB injury manifesting ZO-1 dysregulation.
authors.affiliation: School of Biotechnology, Centre for Preventive Medicine, Dublin City University, Glasnevin, Dublin 9, Ireland.
authors.forename: Keith D
authors.initials: KD
authors.lastname: Rochfort
authors.affiliation: School of Biotechnology, Centre for Preventive Medicine, Dublin City University, Glasnevin, Dublin 9, Ireland. Electronic address: phil.cummins@dcu.ie.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Cummins
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D001812:Blood-Brain Barrier / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D002199:Capillary Permeability / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D015850:Interleukin-6 / Q000494:pharmacology*; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D055806:Microvessels / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D034622:RNA Interference; D017382:Reactive Oxygen Species / Q000378:metabolism; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D062826:Zonula Occludens-1 Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D004791:Enzyme Inhibitors; D015850:Interleukin-6; D008562:Membrane Glycoproteins; D017382:Reactive Oxygen Species; C569042:TJP1 protein, human; D014409:Tumor Necrosis Factor-alpha; D062826:Zonula Occludens-1 Protein; C056558:CYBB protein, human; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1
keywords: Blood–brain barrier; Cytokine; Endothelial; NADPH oxidase; Zonula occludens-1