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Mouse SPNS2 functions as a sphingosine-1-phosphate transporter in vascular endothelial cells.

Hisano Y, Kobayashi N, Yamaguchi A, Nishi T - PLoS ONE (2012)

Bottom Line: However, little is known about the molecular mechanism by which S1P is supplied to extracellular environments such as blood plasma.Here, we show that SPNS2 functions as an S1P transporter in vascular endothelial cells but not in erythrocytes and platelets.Moreover, the plasma S1P concentration of SPNS2-deficient mice was reduced to approximately 60% of wild-type, and SPNS2-deficient mice were lymphopenic.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka, Japan.

ABSTRACT
Sphingosine-1-phosphate (S1P), a sphingolipid metabolite that is produced inside the cells, regulates a variety of physiological and pathological responses via S1P receptors (S1P1-5). Signal transduction between cells consists of three steps; the synthesis of signaling molecules, their export to the extracellular space and their recognition by receptors. An S1P concentration gradient is essential for the migration of various cell types that express S1P receptors, such as lymphocytes, pre-osteoclasts, cancer cells and endothelial cells. To maintain this concentration gradient, plasma S1P concentration must be at a higher level. However, little is known about the molecular mechanism by which S1P is supplied to extracellular environments such as blood plasma. Here, we show that SPNS2 functions as an S1P transporter in vascular endothelial cells but not in erythrocytes and platelets. Moreover, the plasma S1P concentration of SPNS2-deficient mice was reduced to approximately 60% of wild-type, and SPNS2-deficient mice were lymphopenic. Our results demonstrate that SPNS2 is the first physiological S1P transporter in mammals and is a key determinant of lymphocyte egress from the thymus.

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Related in: MedlinePlus

SPNS2-deficient mice.(A) Targeting scheme to generate the Spns2 genomicdeletion allele. The exons of the putative coding and noncoding regionsare shown as black and white boxes, respectively. TheLacZ-neor cassette in the deletedallele is indicated with a white rectangle. The primers used forgenotyping are indicated by arrows. (B) Deletion of mouseSpns2 from the genome was confirmed with PCR usinggenomic DNA isolated fromSpns2+/+,Spns2+/− andSpns2−/− mouse tails. (C)Knock-out of mouse Spns2 was confirmed by conventionalRT-PCR using mRNA isolated fromSpns2+/+ orSpns2−/− mousetissues.
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pone-0038941-g002: SPNS2-deficient mice.(A) Targeting scheme to generate the Spns2 genomicdeletion allele. The exons of the putative coding and noncoding regionsare shown as black and white boxes, respectively. TheLacZ-neor cassette in the deletedallele is indicated with a white rectangle. The primers used forgenotyping are indicated by arrows. (B) Deletion of mouseSpns2 from the genome was confirmed with PCR usinggenomic DNA isolated fromSpns2+/+,Spns2+/− andSpns2−/− mouse tails. (C)Knock-out of mouse Spns2 was confirmed by conventionalRT-PCR using mRNA isolated fromSpns2+/+ orSpns2−/− mousetissues.

Mentions: SPNS2-deficient mice were generated by the disruption of exon 3–4, whichcontains the codon encoding Arg200, an amino acid that is essential for S1Pexport activity (Figure 1and FigureS1) [28]. Spns2 deficiency was confirmed bythe absence of Spns2 exons and mRNA (Figure 2). Although SPNS2-deficient mice wereborn in the expected Mendelian ratios, they displayed an eye-open at birth (EOB)phenotype, and approximately 40% of them succumbed to cryptogenic deathat 4 to 5 weeks of age (Figure S2). Therefore, we used 4-week-oldmice for our studies to avoid analyzing a biased population of SPNS2-deficientmice. Other than the EOB phenotype, the SPNS2-deficient mice showed noabnormalities in the cardiovascular system or other organs, suggesting thatthere are functional differences between zebrafish and mammals in thephysiological roles of SPNS2 in cardiogenesis.


Mouse SPNS2 functions as a sphingosine-1-phosphate transporter in vascular endothelial cells.

Hisano Y, Kobayashi N, Yamaguchi A, Nishi T - PLoS ONE (2012)

SPNS2-deficient mice.(A) Targeting scheme to generate the Spns2 genomicdeletion allele. The exons of the putative coding and noncoding regionsare shown as black and white boxes, respectively. TheLacZ-neor cassette in the deletedallele is indicated with a white rectangle. The primers used forgenotyping are indicated by arrows. (B) Deletion of mouseSpns2 from the genome was confirmed with PCR usinggenomic DNA isolated fromSpns2+/+,Spns2+/− andSpns2−/− mouse tails. (C)Knock-out of mouse Spns2 was confirmed by conventionalRT-PCR using mRNA isolated fromSpns2+/+ orSpns2−/− mousetissues.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3379171&req=5

pone-0038941-g002: SPNS2-deficient mice.(A) Targeting scheme to generate the Spns2 genomicdeletion allele. The exons of the putative coding and noncoding regionsare shown as black and white boxes, respectively. TheLacZ-neor cassette in the deletedallele is indicated with a white rectangle. The primers used forgenotyping are indicated by arrows. (B) Deletion of mouseSpns2 from the genome was confirmed with PCR usinggenomic DNA isolated fromSpns2+/+,Spns2+/− andSpns2−/− mouse tails. (C)Knock-out of mouse Spns2 was confirmed by conventionalRT-PCR using mRNA isolated fromSpns2+/+ orSpns2−/− mousetissues.
Mentions: SPNS2-deficient mice were generated by the disruption of exon 3–4, whichcontains the codon encoding Arg200, an amino acid that is essential for S1Pexport activity (Figure 1and FigureS1) [28]. Spns2 deficiency was confirmed bythe absence of Spns2 exons and mRNA (Figure 2). Although SPNS2-deficient mice wereborn in the expected Mendelian ratios, they displayed an eye-open at birth (EOB)phenotype, and approximately 40% of them succumbed to cryptogenic deathat 4 to 5 weeks of age (Figure S2). Therefore, we used 4-week-oldmice for our studies to avoid analyzing a biased population of SPNS2-deficientmice. Other than the EOB phenotype, the SPNS2-deficient mice showed noabnormalities in the cardiovascular system or other organs, suggesting thatthere are functional differences between zebrafish and mammals in thephysiological roles of SPNS2 in cardiogenesis.

Bottom Line: However, little is known about the molecular mechanism by which S1P is supplied to extracellular environments such as blood plasma.Here, we show that SPNS2 functions as an S1P transporter in vascular endothelial cells but not in erythrocytes and platelets.Moreover, the plasma S1P concentration of SPNS2-deficient mice was reduced to approximately 60% of wild-type, and SPNS2-deficient mice were lymphopenic.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka, Japan.

ABSTRACT
Sphingosine-1-phosphate (S1P), a sphingolipid metabolite that is produced inside the cells, regulates a variety of physiological and pathological responses via S1P receptors (S1P1-5). Signal transduction between cells consists of three steps; the synthesis of signaling molecules, their export to the extracellular space and their recognition by receptors. An S1P concentration gradient is essential for the migration of various cell types that express S1P receptors, such as lymphocytes, pre-osteoclasts, cancer cells and endothelial cells. To maintain this concentration gradient, plasma S1P concentration must be at a higher level. However, little is known about the molecular mechanism by which S1P is supplied to extracellular environments such as blood plasma. Here, we show that SPNS2 functions as an S1P transporter in vascular endothelial cells but not in erythrocytes and platelets. Moreover, the plasma S1P concentration of SPNS2-deficient mice was reduced to approximately 60% of wild-type, and SPNS2-deficient mice were lymphopenic. Our results demonstrate that SPNS2 is the first physiological S1P transporter in mammals and is a key determinant of lymphocyte egress from the thymus.

Show MeSH
Related in: MedlinePlus