TY - JOUR
T1 - Increased plasma sphingosine-1-phosphate in obese individuals and its capacity to increase the expression of plasminogen activator inhibitor-1 in adipocytes
AU - Ito, Shiori
AU - Iwaki, Soichiro
AU - Koike, Keiko
AU - Yuda, Yuichiro
AU - Nagasaki, Ayako
AU - Ohkawa, Ryunosuke
AU - Yatomi, Yutaka
AU - Furumoto, Tomoo
AU - Tsutsui, Hiroyuki
AU - Sobel, Burton E.
AU - Fujii, Satoshi
PY - 2013/12
Y1 - 2013/12
N2 - OBJECTIVES: Concentrations of plasminogen activator inhibitor-1 (PAI-1) are increased in obese individuals. One source of PAI-1 is adipocytes. Hypoxia develops within adipose tissue as it expands, presumably contributing to increased levels of sphingosine-1-phosphate (S1P). S1P is a breakdown product of sphingosine, ubiquitous in cell membranes. We have shown previously that S1P increases the expression of PAI-1 in human liver-derived cell line. In the present study, we aimed to determine whether hypoxia induces S1P in adipocytes, thereby potentially contributing to an increase in PAI-1 and hence constraints on fibrinolysis associated with obesity. MATERIALS AND METHODS: Mouse 3T3-L1 adipocytes were exposed to CoCl2 to simulate hypoxia. Assays were performed for PAI-1 mRNA (quantitative PCR) and S1P (high-performance liquid chromatography). RESULTS: The physiologic concentration of S1P increased PAI-1 mRNA expression. The S1P2 receptor antagonist attenuated the increase in PAI-1. Adipocytes expressed sphingosine kinase 1/2 (SPHK1/2) and S1P lyase, key enzymes involved in S1P production and degradation. Hypoxia increased SPHK activity and decreased S1P lyase mRNA. Hypoxia reduced cytosolic sphingosine and increased S1P release into conditioned medium. Inhibitors of ABCA1 and ABCC1 reduced the release of S1P into conditioned media. In obese patients with uncomplicated dyslipidemia and hypertension, plasma S1P was increased compared with that in nonobese and lean individuals. CONCLUSION: Hypoxia in adipose tissue of obesity can promote elaboration of S1P that binds to S1P2 receptors in an autocrine or a paracrine manner. S1P potentially contributes toward increased expression of PAI-1 and consequent constraints on fibrinolysis. S1P production and extracellular transport provide an attractive target for therapy to attenuate impaired fibrinolysis associated with obesity.
AB - OBJECTIVES: Concentrations of plasminogen activator inhibitor-1 (PAI-1) are increased in obese individuals. One source of PAI-1 is adipocytes. Hypoxia develops within adipose tissue as it expands, presumably contributing to increased levels of sphingosine-1-phosphate (S1P). S1P is a breakdown product of sphingosine, ubiquitous in cell membranes. We have shown previously that S1P increases the expression of PAI-1 in human liver-derived cell line. In the present study, we aimed to determine whether hypoxia induces S1P in adipocytes, thereby potentially contributing to an increase in PAI-1 and hence constraints on fibrinolysis associated with obesity. MATERIALS AND METHODS: Mouse 3T3-L1 adipocytes were exposed to CoCl2 to simulate hypoxia. Assays were performed for PAI-1 mRNA (quantitative PCR) and S1P (high-performance liquid chromatography). RESULTS: The physiologic concentration of S1P increased PAI-1 mRNA expression. The S1P2 receptor antagonist attenuated the increase in PAI-1. Adipocytes expressed sphingosine kinase 1/2 (SPHK1/2) and S1P lyase, key enzymes involved in S1P production and degradation. Hypoxia increased SPHK activity and decreased S1P lyase mRNA. Hypoxia reduced cytosolic sphingosine and increased S1P release into conditioned medium. Inhibitors of ABCA1 and ABCC1 reduced the release of S1P into conditioned media. In obese patients with uncomplicated dyslipidemia and hypertension, plasma S1P was increased compared with that in nonobese and lean individuals. CONCLUSION: Hypoxia in adipose tissue of obesity can promote elaboration of S1P that binds to S1P2 receptors in an autocrine or a paracrine manner. S1P potentially contributes toward increased expression of PAI-1 and consequent constraints on fibrinolysis. S1P production and extracellular transport provide an attractive target for therapy to attenuate impaired fibrinolysis associated with obesity.
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U2 - 10.1097/MCA.0000000000000033
DO - 10.1097/MCA.0000000000000033
M3 - Article
C2 - 24212262
AN - SCOPUS:84888115274
SN - 0954-6928
VL - 24
SP - 642
EP - 650
JO - Coronary Artery Disease
JF - Coronary Artery Disease
IS - 8
ER -
