The University of Tokyo · Medicine
Professor Yutaka Yatomi's research lab specializes in lipid signaling, with a primary focus on sphingosine 1-phosphate (Sph-1-P), a bioactive sphingolipid mediator. The lab investigates the metabolism, cellular functions, and physiological roles of Sph-1-P in human platelets and body fluids, particularly its involvement in platelet activation, secretion, and intercellular communication. Key research directions include the identification and quantification of Sph-1-P in human plasma and serum, its release from activated platelets, and the mechanisms underlying its extracellular signaling, including interactions with albumin and surface receptor engagement. The lab also explores the enzymatic pathways regulating Sph-1-P synthesis and degradation, especially in the context of platelet function and vascular biology.
Figures are computed from collected data and may differ slightly.
Sphingosine-1-phosphate (Sph-1-P) is the initial product of catabolism of sphingosine by sphingosine kinase and is cleaved by Sph-1-P lyase to a fatty aldehyde and ethanolamine phosphate. This phosphorylated sphingoid base is not only an intermediary catabolite, but also a bioactive lipid with important functions, including stimulation of cell proliferation in Swiss 3T3 fibroblasts and inhibition of tumor cell motility. In the present study, we examined functional roles of Sph-1-P in human plate
Although sphingosine 1-phosphate (Sph-1-P) is reportedly involved in diverse cellular processes and the physiological roles of this bioactive sphingolipid have been strongly suggested, few studies have revealed the presence of Sph-1-P in human samples, including body fluids and cells, under physiological conditions. In this study, we identified Sph-1-P as a normal constituent of human plasma and serum. The Sph-1-P levels in plasma and serum were 191+/-79 and 484+/-82 pmol/ml (mean+/-SD, n=8), re
The serum-borne lysophospholipid mediators sphingosine 1-phosphate (Sph-1-P) and lysophosphatidic acid (LPA) have been shown to be released from activated platelets and to act on endothelial cells. In this study, we employed the repeated lipid extraction (under alkaline and acidic conditions), capable of detecting Sph-1-P, LPA, and possibly structurally similar lysophospholipids, whereby a marked formation of [(32)P]Sph-1-P, but not [(32)P]LPA, was observed in [(32)P]orthophosphate-labeled plate
Sphingosine 1-phosphate (Sph-1-P) has been implicated as an intracellular second messenger in many studies. We investigated the metabolism of Sph-1-P and the mechanism by which Sph-1-P induces activation in enucleated and highly differentiated platelets. Platelets lack Sph-1-P lyase activity, possess persistently active sphingosine (Sph) kinase, and abundantly store Sph-1-P. Although exogenous Sph-1-P activated platelets, intracellular Sph-1-P, formed from exogenously added Sph by cytosolic Sph
Potential sphingosine (Sph) metabolites include phosphorylated, N-acylated, and N-methylated derivatives. Phosphorylated Sph, i.e., sphingosine 1-phosphate (Sph-1-P), may act as an autocrine stimulator of blood platelets, as it is abundantly stored in platelets and released extracellularly and its exogenous addition induces platelet activation. In this study, we evaluated Sph-1-P formation and its effects in human platelets in the presence of other Sph metabolites. On addition of [3H]Sph to inta
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