Marked perinatal lethality and cellular signaling deficits in mice null for the two sphingosine 1-phosphate (S1P) receptors, S1P(2)/LP(B2)/EDG-5 and S1P(3)/LP(B3)/EDG-3.
Five cognate G protein-coupled receptors (S1P(1-5)) have been shown to mediate various cellular effects of sphingosine 1-phosphate (S1P). Here we report the generation of mice null for S1P(2) and for both S1P(2) and S1P(3). S1P(2)-null mice were viable and fertile and developed normally. The litter sizes from S1P(2)S1P(3) double-null crosses were remarkably reduced compared with controls, and double-null pups often did not survive through infancy, although double-null survivors lacked any obvious phenotype. Mouse embryonic fibroblasts (MEFs) were examined for the effects of receptor deletions on S1P signaling pathways. Wild-type MEFs were responsive to S1P in activation of Rho and phospholipase C (PLC), intracellular calcium mobilization, and inhibition of forskolin-activated adenylyl cyclase. S1P(2)-null MEFs showed a significant decrease in Rho activation, but no effect on PLC activation, calcium mobilization, or adenylyl cyclase inhibition. Double-null MEFs displayed a complete loss of Rho activation and a significant decrease in PLC activation and calcium mobilization, with no effect on adenylyl cyclase inhibition. These data extend our previous findings on S1P(3)-null mice and indicate preferential coupling of the S1P(2) and S1P(3) receptors to Rho and PLC/Ca(2+) pathways, respectively. Although either receptor subtype supports embryonic development, deletion of both produces marked perinatal lethality, demonstrating an essential role for combined S1P signaling by these receptors.
Ishii
Isao
I
Department of Pharmacology, School of Medicine, University of California at San Diego, La Jolla 92093-0636, USA.
Ye
Xiaoqin
X
Friedman
Beth
B
Kawamura
Shuji
S
Contos
James J A
JJ
Kingsbury
Marcy A
MA
Yang
Amy H
AH
Zhang
Guangfa
G
Brown
Joan Heller
JH
Chun
Jerold
J
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D005260:Female; D005804:Genes, Lethal; D020672:I-kappa B Proteins; D008098:Litter Size; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D000072000:NF-KappaB Inhibitor alpha; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D043562:Receptors, G-Protein-Coupled; D049312:Receptors, Lysophospholipid; D015398:Signal Transduction
D017931:DNA Primers; D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; C000606205:Nfkbia protein, mouse; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D049312:Receptors, Lysophospholipid; D000072000:NF-KappaB Inhibitor alpha; D000262:Adenylyl Cyclases; D002118:Calcium