Edg-1, the G protein–coupled receptor for sphingosine-1-phosphate, is essential for vascular maturation
Yujing Liu, Ryuichi Wada, Tadashi Yamashita, Yide Mi, Chu-Xia Deng, John P. Hobson, Hans M. Rosenfeldt, Victor E. Nava, Sung-Suk Chae, Menq-Jer Lee, Catherine H. Liu, Timothy Hla, Sarah Spiegel, Richard L. Proia
Yujing Liu, Ryuichi Wada, Tadashi Yamashita, Yide Mi, Chu-Xia Deng, John P. Hobson, Hans M. Rosenfeldt, Victor E. Nava, Sung-Suk Chae, Menq-Jer Lee, Catherine H. Liu, Timothy Hla, Sarah Spiegel, Richard L. Proia
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Article

Edg-1, the G protein–coupled receptor for sphingosine-1-phosphate, is essential for vascular maturation

Abstract

Sphingolipid signaling pathways have been implicated in many critical cellular events. Sphingosine-1-phosphate (SPP), a sphingolipid metabolite found in high concentrations in platelets and blood, stimulates members of the endothelial differentiation gene (Edg) family of G protein–coupled receptors and triggers diverse effects, including cell growth, survival, migration, and morphogenesis. To determine the in vivo functions of the SPP/Edg signaling pathway, we disrupted the Edg1 gene in mice. Edg1–/– mice exhibited embryonic hemorrhage leading to intrauterine death between E12.5 and E14.5. Vasculogenesis and angiogenesis appeared normal in the mutant embryos. However, vascular maturation was incomplete due to a deficiency of vascular smooth muscle cells/pericytes. We also show that Edg-1 mediates an SPP-induced migration response that is defective in mutant cells due to an inability to activate the small GTPase, Rac. Our data reveal Edg-1 to be the first G protein–coupled receptor required for blood vessel formation and show that sphingolipid signaling is essential during mammalian development.

Authors

Yujing Liu, Ryuichi Wada, Tadashi Yamashita, Yide Mi, Chu-Xia Deng, John P. Hobson, Hans M. Rosenfeldt, Victor E. Nava, Sung-Suk Chae, Menq-Jer Lee, Catherine H. Liu, Timothy Hla, Sarah Spiegel, Richard L. Proia

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Figure 1

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Targeted disruption and embryonic expression of the Edg1 gene. (a) Schem...
Targeted disruption and embryonic expression of the Edg1 gene. (a) Schematic representation of the Edg1 targeting strategy. The structure of the mouse Edg1 locus is shown at the top, the structure of the Edg1 targeting vector in the middle, and the predicted structure of the homologous recombined locus on the bottom. RT-5′ and RT-3′, primers for RT-PCR. B, BamHI; Bgl, BglII; PBSK, pBluescript vector. (b) Genotyping of mouse offspring from the Edg1 heterozygous mating. Wild-type Edg1 locus yielded a 9.5-kb BamHI band. Disrupted Edg1 locus yielded a 2.5-kb BamHI band. No Edg1–/– mice were found born alive. (c) RT-PCR analysis of total RNA from E12.5 mouse embryos by using RT-5′ and RT-3′. Edg1+/+ and Edg1+/– RNA yielded the predicted 630-bp amplification product. No amplification product was detected from Edg1–/– RNA. (d, e) Whole-mount of Edg1+/– E9.5 and E10.5 embryos stained with X-Gal. H, heart; DA, dorsal aorta; ISA, intersomatic arteries; CP, capillaries; TC, telencephalon; ACV, anterior cardinal vein. (f) Longitudinal section of dorsal aorta (DA) from E10.5 Edg1+/– embryo. LacZ staining is seen in arterial ECs (AEC). (g) Longitudinal section of posterior cardinal vein (PCV) from E10.5 Edg1+/– embryo. LacZ staining is seen in arterial endothelial cells (AEC) but not in venous endothelial cells (VEC). (h) Transverse section of dorsal aorta from E12.5 Edg1+/– embryo. Vascular ECs and VSMCs are stained. EC, endothelial cell; VSMC, vascular smooth muscle cell. Scale bars = 50 μm.