Endothelin-1-induced interleukin-8 production in human brain-derived endothelial cells is mediated by the protein kinase C and protein tyrosine kinase pathways.
We have previously demonstrated that endothelin-1 (Et-1) induces human central nervous system-derived endothelial cells (CNS-EC) to produce and secrete the chemokine interleukin 8 (IL-8). In the present study, we use specific inhibitors and activators to elucidate the signal transduction pathways involved in this process. Et-1-induced IL-8 production was blocked by ET(A) receptor antagonist BQ610, but not by ET(B) receptor antagonist BQ788, demonstrating that CNS-EC activation is initiated by Et-1 binding to the ET(A) receptor. IL-8 mRNA expression is blocked by the protein kinase C inhibitor bisindolylmaleimide or protein tyrosine kinase inhibitors, genestein and geldanamycin, establishing the involvement of the protein kinase C and protein tyrosine kinase pathways in the activation process. The transcription factor, NF-kappaB, is involved in Et-1 activation as determined by specific inhibitors of translocation and direct analysis of DNA-binding proteins. Neither inhibition nor activation of cAMP-dependent protein kinase affected IL-8 production in the absence or presence of Et-1. Similarly, no effect was observed upon inhibition of protein phosphatases by okadaic acid. Thus, the signal transduction process induced by Et-1 in CNS-EC, leading to increased mRNA IL-8 expression, is initiated by Et-1 binding to ET(A) receptor followed by subsequent activation of protein kinase C, protein tyrosine kinase, and NF-kappaB. Because increased expression of Et-1 is associated with hypertension and stroke and IL-8 is likely to be involved in the accumulation of neutrophils causing tissue damage in ischemic/reperfusion injury, identification of the mechanism involved in the Et-1-induced increase in IL-8 production may have significant therapeutic value.
Zidovetzki
R
R
Departments of Biology and Neuroscience, University of California, Riverside, CA, USA.
Chen
P
P
Chen
M
M
Hofman
F M
FM
D000959:Antihypertensive Agents / Q000494:pharmacology; D001921:Brain / Q000098:blood supply / Q000166:cytology; D002478:Cells, Cultured; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology*; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis*; D009842:Oligopeptides / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D017466:Receptors, Endothelin / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects
D000959:Antihypertensive Agents; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D016209:Interleukin-8; D009842:Oligopeptides; D010880:Piperidines; D017466:Receptors, Endothelin; C087220:BQ 610; C086539:BQ 788