Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/23882
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Type: Journal article
Title: Sphingosine kinase functionally links elevated transmural pressure and increased reactive oxygen species formation in resistance arteries
Author: Keller, M.
Lidington, D.
Vogel, L.
Peter, B.
Sohn, H.
Pagano, P.
Pitson, S.
Spiegel, S.
Pohl, U.
Bolz, S.
Citation: FASEB Journal, 2006; 20(6):1-20
Publisher: Federation of American Societies for Experimental Biology
Issue Date: 2006
ISSN: 0892-6638
1530-6860
Statement of
Responsibility: 
Matthias Keller, Darcy Lidington, Lukas Vogel, Bernhard Friedrich Peter, Hae-Young Sohn, Patrick J. Pagano, Stuart Pitson, Sarah Spiegel, Ulrich Pohl, and Steffen-Sebastian Bolz
Abstract: Myogenic vasoconstriction, an intrinsic response to elevated transmural pressure (TMP), requires the activation of sphingosine kinase (Sk1) and the generation of reactive oxygen species (ROS). We hypothesized that pressure-induced Sk1 signaling and ROS generation are functionally linked. Using a model of cannulated resistance arteries isolated from the hamster gracilis muscle, we monitored vessel diameter and smooth muscle cell (SMC) Ca²⁺ i (Fura-2) or ROS production (dichlorodihydrofluorescein). Elevation of TMP stimulated the translocation of a GFP-tagged Sk1 fusion protein from the cytosol to the plasma membrane, indicative of enzymatic activation. Concurrently, elevation of TMP initiated a rapid and transient production of ROS, which was enhanced by expression of wild-type Sk1 (hSkwt) and inhibited by its dominant-negative mutant (hSkG82D). Exogenous sphingosine-1-phosphate (S1P) also stimulated ROS generation is isolated vessels. Chemical (1μmol/L DPI), peptide (gp91ds-tat/gp91ds), and genetic (N17Rac) inhibition strategies indicated that NADPH oxidase was the source of the pressure-induced ROS. NADPH oxidase inhibition attenuated myogenic vasoconstriction and reduced the apparent Ca²⁺ sensitivity of the SMC contractile apparatus, without affecting Ca²⁺-independent, RhoAmediated vasoconstriction in response to exogenous S1P. Our results indicate a mandatory role for Sk1/S1P in mediating pressure-induced, NADPH oxidase-derived ROS formation. In turn, ROS generation appears to increase Ca²⁺ sensitivity, necessary for full myogenic vasoconstriction.
Keywords: smooth muscle; signal transduction; transfection; NADPH oxidase; Ca²⁺ sensitization
Description: Published online February 13, 2006
Rights: ©2006 FASEB
RMID: 0020060611
DOI: 10.1096/fj.05-4075fje
Appears in Collections:Agriculture, Food and Wine publications

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