Interleukin-1 drives cerebrovascular inflammation via MAP kinase-independent pathways.
Cerebrovascular inflammation is triggered by diverse central nervous system (CNS) insults and contributes to disease pathogenesis. The pro-inflammatory cytokine interleukin (IL)-1 is central to this cerebrovascular inflammatory response and understanding the underlying signalling mechanisms of IL-1 actions in brain endothelium may provide therapeutic targets for disease intervention. For the first time, we compare the contributions of p38, JNK and ERK mitogen-activated protein (MAP) kinase and NF-kB pathways to IL-1-induced brain endothelial activation. In cultures of primary mouse brain endothelium and the rat brain endothelial GPNT cell line, interleukin-1β (IL-1β induced a rapid (within 5 minutes) and transient activation of p38 and JNK (but not ERK) MAP kinases. IL-1β also induced nuclear recruitment of nuclear factor (NF)-kB p65. IL-1β-induced brain endothelial expression of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 was insensitive to MAP kinase inhibitors. IL-1β-induced brain endothelial expression of ICAM-1 and VCAM-1 was inhibited (80-88 %) by the proteasome inhibitor MG132 or the antioxidant caffeic acid phenethyl ester (CAPE), effects suggested to be NF-kB-dependent. IL-1β-induced brain endothelial CXCL1 expression was partially inhibited by JNK MAP kinase or MG132 (62 or 56 %, respectively). However, CXCL1 secretion from brain endothelium was reduced (65 %) only by MG132, and not MAP kinase inhibitors. Similarly, IL-1β-induced neutrophil transendothelial migration was reduced (77-89 %) by MG132, but not MAP kinase inhibitors. In summary, we show that several key components of IL-1β-induced brain endothelial activation (CAM, CXCL1 expression or release and neutrophil transmigration) are largely independent of MAP kinase activity but are reduced by proteasome inhibition, possibly reflecting a requirement for NF-kB activity. Similar mechanisms may contribute to cerebrovascular inflammation in response to CNS injury.
Thornton
Peter
P
Faculty of Life Sciences, A.V. Hill Building, University of Manchester, Oxford Road, Manchester, M13 9PT, UK.
McColl
Barry W
BW
Cooper
Laura
L
Rothwell
Nancy J
NJ
Allan
Stuart M
SM
D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000166:cytology; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D042783:Endothelial Cells / Q000187:drug effects* / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D053590:Interleukin 1 Receptor Antagonist Protein / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects*
D004791:Enzyme Inhibitors; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D016328:NF-kappa B; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011500:Protein Synthesis Inhibitors; D003513:Cycloheximide; D020929:Mitogen-Activated Protein Kinase Kinases