Sphingosine kinase 1 is essential for proteinase-activated receptor-1 signalling in epithelial and endothelial cells.
There is accumulating evidence that activation of sphingosine kinase 1 (SPHK1) is an important element in intracellular signalling cascades initiated by stimulation of multiple receptors, including certain growth factor, cytokine, and also G-protein coupled receptors. We here report that stimulation of the lung epithelial cell line A549 by thrombin leads to transient increase of SPHK1 activity and elevation of intracellular sphingosine-1-phosphate (S1P); abrogation of this stimulation by SPHK1-specific siRNA, pharmacological inhibition, or expression of a dominant-negative SPHK1 mutant blocks the response to thrombin, as measured by secretion of MCP-1, IL-6, IL-8, and PGE(2). Using selective stimulation of proteinase-activated receptors (PARs) a specific involvement of SPHK1 in the PAR-1 induced responses in A549 cell, including activation of NFkappaB, was evident, while PAR-2 and PAR-4 responses were independent of SPHK1. Moreover, PAR-1 or thrombin-induced cytokine production and adhesion factor expression of human umbilical vein endothelial cells was also seen to depend on SPHK1. Using dermal microvascular endothelial cells from SPHK1-deficient mice, we showed that absence of the enzyme abrogates MCP-1 production induced in these cells upon treatment with thrombin or PAR-1 activating peptide. We propose SPHK1 inhibition as a novel way to block PAR-1 mediated signalling, which could be useful in treatment of a number of diseases, in particular in atherosclerosis.
Billich
Andreas
A
Novartis Institutes for BioMedical Research, Brunnerstrasse 59, Vienna, Austria. andreas.billich@novartis.com
Urtz
Nicole
N
Reuschel
Roland
R
Baumruker
Thomas
T
D000818:Animals; D045744:Cell Line, Tumor; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D015232:Dinoprostone / Q000096:biosynthesis; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects / Q000201:enzymology*; D005786:Gene Expression Regulation / Q000187:drug effects; D020868:Gene Silencing / Q000187:drug effects; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D015850:Interleukin-6 / Q000096:biosynthesis; D016209:Interleukin-8 / Q000096:biosynthesis; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D044463:Receptor, PAR-1 / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013844:Thiazoles / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology; D000099157:Sphingosine Kinase
D018932:Chemokine CCL2; D051546:Cyclooxygenase 2; D015232:Dinoprostone; D018799:Intercellular Adhesion Molecule-1; D015850:Interleukin-6; D016209:Interleukin-8; D016328:NF-kappa B; D017853:Phosphotransferases (Alcohol Group Acceptor); D012333:RNA, Messenger; D034741:RNA, Small Interfering; D044463:Receptor, PAR-1; D013844:Thiazoles; D013917:Thrombin; D000099157:Sphingosine Kinase; C525025:4-(4-(4-chloro-phenyl)thiazol-2-ylamino)phenol; C111835:CCL2 protein, human; C496540:PTGS2 protein, human