Sphingosylphosphorylcholine stimulates contraction of fibroblast-embedded collagen gel

Sphingosylphosphorylcholine (SPC), a sphingolipid metabolite, has recently been reported to stimulate wound healing in an animal model. To clarify the mechanism of SPC on the healing process, we examined the effect of SPC on wound contraction using an in vitro model. A mixture of human dermal fibroblasts and porcine type I collagen in a serum-free medium was gelled, and then separated from the well after a 12-h incubation. Various reagents were applied to the medium, and its contractile activity was analysed by measuring the amount of contracted surface area. Among the sphingolipid metabolites, SPC and sphingosine-1-phosphate, but not sphingosine, C2-ceramide and C6-ceramide, stimulated collagen gel contraction. Maximal gel contraction, observed at 10 micromol L-1 of SPC, occurred as early as 1 h after the treatment and persisted for more than 48 h. The effect of SPC was not inhibited by pretreatment with antitransforming growth factor-beta or antiplatelet-derived growth factor-BB antibodies. Among the various signal transduction inhibitors, pertussis toxin, staurosporine and H7 were found to inhibit the action of SPC, whereas genistein and tyrphostin A47 were not, suggesting that fibroblast contraction induced by SPC is mediated by a trimeric guanosine triphosphate-binding protein (G protein)-coupled receptor and protein kinase. Our findings imply that the effect of SPC as a healing stimulant might be due in part to stimulation of fibroblast contraction in granulation tissue.