Sphingosine-1-Phosphate Inhibits C-Type Natriuretic Peptide Activation of Guanylyl Cyclase B (GC-B/NPR-B)

Abstract

Abstract-C-type natriuretic peptide (CNP) binds and activates the transmembrane guanylyl cyclase B receptor (NPR-B), which decreases vascular tone and inhibits cell proliferation and migration. In contrast, the bioactive lipid sphingosine-1-phosphate (S1P) elicits the opposite physiological effects. Here, we demonstrate a potent acute inhibitory effect of S1P on NPR-B activity in NIH3T3 fibroblasts and A10 vascular smooth muscle cells. In fibroblasts, S1P reduced CNP-dependent cGMP elevations to the same levels as 10% fetal bovine serum, the most potent NPR-B desensitizing agent known. The reduction was dose-dependent (IC 50 ϭ0.08 mol/L) and due to decreased NPR-B activity because CNP-dependent guanylyl cyclase activities were markedly diminished in membranes prepared from S1P-treated cells. Similarly, in A10 cells, S1P inhibition was rapid (t 1/2 ϭ2 to 5 minutes), dose-dependent (IC 50 ϭ0.3 mol/L S1P), and mediated by a cell surface receptor. The mechanism of the S1P-dependent desensitization in A10 cells did not require NPR-B degradation or protein kinase C activation, but did require elevated calcium concentrations because a nonspecific calcium ionophore also inhibited NPR-B and an intracellular calcium chelator blocked a significant portion of the S1P response. These are the first data demonstrating cross-talk between the natriuretic peptide and S1P signaling systems. They suggest that the effects of S1P on vascular disease and wound healing may be mediated in part through inhibition

Natriuretic Peptides

“…CNP infusions reduce intimal thickening and restenosis after experimental balloon angioplasty injury to vessels. 26 This report 25 indicates S1P, a novel phospholipid signaling molecule released in micromolar concentrations from activated platelets, inhibits GC-B in both fibroblasts and VSMCs. This appears to be the most potent GC-B desensitizing factor identified to date.…”

“…Abbey-Hosch et al 25 demonstrated that sphingosine-1-phosphate (S1P) inhibits GC-B activity. Administration of CNP in whole animal or isolated vascular models induces a reduction in vascular tone and longer term effects include inhibition of vascular smooth muscle cell (VSMC) proliferation and migration.…”

Calcium-dependent Dephosphorylation Mediates the Hyperosmotic and Lysophosphatidic Acid-dependent Inhibition of Natriuretic Peptide Receptor-B/Guanylyl Cyclase-B

“…We recently demonstrated that the arginine-, vasopressin-, and sphingosine-1-phosphatedependent desensitization of NPR-B requires elevated calcium concentrations (17,25). Therefore, we asked whether calcium also mediates the hyperosmotic effect.…”

Membrane guanylyl cyclase receptors: an update

“…The factor was purified and shown to be S1P [46]. The work of AbbeyHosch et al [56] has also shown that S1P can induce desensitization of GCB. S1P is bound principally to high-density lipoprotein (HDL) in serum, where its concentrations (if all considered unbound to protein) range between 500-1000 pM.…”

“…There are five putative S1P receptors, all apparently coupled to G proteins (Figure 3). Importantly, the desensitization of GCB caused by either serum or S1P is pertussis toxin insensitive [45,46,56]. The most widely distributed receptors, S1PR1-S1PR3, have been suggested to couple to pertussis toxin-sensitive Gi or Go, or insensitive Gq and G12 or G13 [57][58][59][60][61].…”