The Sphingosine-1-phosphate Receptors S1P1, S1P2, and S1P3 Function Coordinately during Embryonic Angiogenesis

Abstract

Sphingosine-1-phosphate (S1P) elicits diverse cellular responses through a family of G-protein-coupled receptors. We have shown previously that genetic disruption of the S1P 1 receptor, the most widely expressed of the family, results in embryonic lethality because of its key role within endothelial cells in regulating the coverage of blood vessels by vascular smooth muscle cells. To understand the physiologic functions of the two other widely expressed S1P receptors, we generated S1P 2 and S1P 3 null mice. Neither the S1P 2 null mice nor the S1P 3 null mice exhibited significant embryonic lethality or obvious phenotypic abnormalities. To unmask possible overlapping or collaborative functions between the S1P 1 , S1P 2 , and S1P 3 receptors, we examined embryos with multiple S1P receptor mutations. We found that S1P 1 S1P 2 double null and S1P 1 S1P 2 S1P 3 triple null embryos displayed a substantially more severe vascular phenotype than did embryos with only S1P 1 deleted. We also found partial embryonic lethality and vascular abnormalities in S1P 2 S1P 3 double null embryos. Our results indicate that the S1P 1 , S1P 2 , and S1P 3 receptors have redundant or cooperative functions for the development of a stable and mature vascular system during embryonic development. Sphingosine-1 phosphate (S1P)1 is a sphingolipid metabolite that is present at high levels in the blood (1-3). Through the interaction with a family of five G-protein-coupled receptors (S1P 1-5 ), originally known as EDG receptors, sphingosine-1-phosphate triggers diverse cellular responses, including cytoskeletal changes, proliferation, and migration (1, 4 -8). The S1P 1 , S1P 2 , and S1P 3 receptors are widely expressed, including on embryonic endothelial cells (Table I) (9 -14). S1P 4 and S1P 5 receptor expression is more restricted and found on the cells of the immune and nervous systems (15, 16). The S1P 1 receptor couples selectively to the G i signaling pathway, whereas the S1P 2 and S1P 3 receptors both couple to the G i , G q , and G 12/13 pathways (2,(17)(18)(19)(20). In addition to these five S1P receptors, GPR3, GPR6, GPR12, and GPR63 have been characterized as G-protein-coupled receptors that interact with sphingosine-1-phosphate (21-23).The major physiological effects of S1P receptor signaling defined thus far have been localized to the immune and vascular systems. A global deletion of the S1P 1 receptor in mice results in lethality beginning at E12.5 due to severe hemorrhage as the result of deficient coverage of vessels by vascular smooth muscle cells, a process that occurs during the last stages of angiogenesis and is necessary for stabilizing the vascular system (14). Through analysis of endothelial cell-specific S1P 1 receptor knock-out mice, we have shown that the S1P 1 receptor functions within endothelial cells to regulate vascular smooth muscle cell coverage (24). The function of the S1P 1 receptor in the developing vasculature is also essential for proper limb development (25). Deletion of the S1P 1 receptor in T-cells has re...

Expression patterns of the lysophospholipid receptor genes during mouse early development

“…underdeveloped limbs (Chae et al, 2004), and that a more severe limb abnormality is observed in S1p 1 S1p 2 double null mice (Kono et al, 2004). Chae et al (2004) have shown that S1P 1 signaling in the developing vasculature is essential for proper limb development.…”

“…Mice deficient in each of the LPA or S1P receptor genes (excluding Lpa 4 , Lpa 5 , and S1p 4 ) have been reported, and double-or triple-knockout mice have been produced for Lpa 1-3 and S1p 1-3 (Contos et al, 2000Kingsbury et al, 2003;Ye et al, 2005Ye et al, , 2008Liu et al, 2000;MacLennan et al, 2001MacLennan et al, , 2006Kono et al, 2004Kono et al, , 2007Cinamon et al, 2004;Jaillard et al, 2005;Herr et al, 2007;Means et al, 2007). However, none of the genetically modified mice reported so far appear to exhibit apparent deficiencies in the formation of somites, possibly because of functional compensation or redundancy among LPA/S1P receptor genes.…”

Changes in S1P1 and S1P2 expression during embryonal development and primitive endoderm differentiation of F9 cells

“…Wide-spread hemorrhage and severe edema were observed at E13.5, and the mice could not survive beyond E14.5 [6]. Although both S1P 2 -and S1P 3 -null mice developed normally vascular systems, S1P 1 S1P 2 double knockout mice and S1P 1 S1P 2 S1P 3 triple knockout mice exhibited more severe vascular defects than those of the S1P 1 single knockout mice [23]. About half of the triple null mice exhibited bleeding at E10.5, and most of those died at E11.5.…”

Mechanisms of the negative inotropic effects of sphingosine-1-phosphate on adult mouse ventricular myocytes

“…Hearts from heparinized adult C57Bl/6 or S1P 3-null mice (28) were isolated under isoflurane anesthesia in accordance with protocols approved by the Institutional Animal Care and Use Committee at UCSD. Guidelines for the Care and Use of Laboratory Animals (copyright 1996) were adhered to.…”