Neisseria meningitidis-induced death of cerebrovascular endothelium: mechanisms triggering transcriptional activation of inducible nitric oxide synthase.
The intense host response to meningococcus reflects marked functional and morphological alterations in blood-brain barriers. We showed previously that mouse-derived cerebrovascular endothelium responded to meningococcal lysates with a robust nitric oxide (NO) response, resulting in the loss of cell viability. To understand how the NO synthase-2 gene in endothelium is activated by meningococcus, we investigated upstream roles for specific protein kinases. Using known kinase inhibitors, and measuring both mRNA expression and nitrite release, we found MAPK/ERK kinase (MEK)2, p38 kinase and phosphoinositide 3-kinase (but not MEK1 or phospholipase C) to be implicated in the NO synthase-2 response. Recruitment of these kinases by meningococcus did not depend on the prior release of the proinflammatory cytokines tumour necrosis factor alpha or interleukin-1beta from endothelium. These endothelial cells were found to express toll-like receptors (TLR) 2, 4 and 9 and antibodies directed against TLR 2 and 4 (but not TLR 9) blocked the NO synthase-2 response to meningococcus. Both meningococcus-induced translocation of nuclear factor-kB (NF-kB) and endothelial cell death were blocked by a known inhibitor of p38 kinase. Calpain inhibitor-1 blocked the NO synthase-2 response to meningococcus, which is further evidence of a role for NF-kB.
Constantin
Despina
D
Institute of Cell Signalling, Division of Microbiology and Infectious Diseases, Medical School, University of Nottingham, University Hospital, Queen's Medical Centre, Clifton Boulevard, Nottingham NG7 2UH, UK.
Cordenier
Axelle
A
Robinson
Karen
K
Ala'Aldeen
Dlawer A A
DA
Murphy
Sean
S
D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000818:Animals; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002560:Cerebrovascular Circulation; D045424:Complex Mixtures / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000382:microbiology*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000096:biosynthesis / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008585:Meningitis, Meningococcal / Q000378:metabolism*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009345:Neisseria meningitidis / Q000472:pathogenicity*; D019001:Nitric Oxide Synthase / Q000235:genetics* / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors; D015533:Transcriptional Activation / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases
D045424:Complex Mixtures; D004791:Enzyme Inhibitors; D007093:Imidazoles; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D020928:Mitogen-Activated Protein Kinases; D016328:NF-kappa B; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D019869:Phosphatidylinositol 3-Kinases; D011725:Pyridines; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D051195:Toll-Like Receptor 2; D051193:Toll-Like Receptors; D048051:p38 Mitogen-Activated Protein Kinases; C496317:Nos2 protein, mouse; C093642:SB 203580