出版社：American Society for Biochemistry and Molecular Biology
摘要：Sphingosylphosphorylcholine (SPC) has been implicated in a varietyof cellular responses, including proliferation and differentiation.In this study, we demonstrate that D-erythro-SPC, but not L-threo-SPC,stereoselectively stimulated the proliferation of human adiposetissue-derived mesenchymal stem cells (hADSCs), with a maximalincrease at 5 µM, and increased the intracellular concentrationof Ca2+ ([Ca2+]i) in hADSCs, which do not express known SPCreceptors (i.e., OGR1, GPR4, G2A, and GPR12). The SPC-inducedproliferation and increase in [Ca2+]i were sensitive to pertussistoxin (PTX) and the phospholipase C (PLC) inhibitor U73122,suggesting that PTX-sensitive G proteins, Gi or Go, and PLCare involved in SPC-induced proliferation. In addition, SPCtreatment induced the phosphorylation of c-Jun and extracellularsignal-regulated kinase, and SPC-induced proliferation was completelyprevented by pretreatment with the c-Jun N-terminal kinase (JNK)-specificinhibitor SP600125 but not with the MEK-specific inhibitor U0126.Furthermore, the SPC-induced proliferation and JNK activationwere completely attenuated by overexpression of a dominant negativemutant of JNK2, and the SPC-induced activation of JNK was inhibitedby pretreatment with PTX or U73122. Treatment of hADSCs withlysophosphatidic acid (LPA) receptor antagonist, Ki16425, hadno impact on the SPC-induced increase in [Ca2+]i. However, SPC-inducedproliferation was partially, but significantly, attenuated bypretreatment of the cells with Ki16425.These results indicatethat SPC stimulates the proliferation of hADSCs through theGi/Go-PLC-JNK pathway and that LPA receptors may be responsiblein part for the SPC-induced proliferation.Supplementary key words c-Jun N-terminal kinase • phospholipase C • G proteins
Abbreviations: BAPTA, 1,2-bis(o-aminophenoxy)ethane-N,N,N,N-tetraacetic acid; [Ca2+]i, intracellular concentration of Ca2+; DN-JNK2, dominant negative mutant of JNK2; DN-MEK1, dominant negative mutant of MEK1; ERK, extracellular signal-regulated kinase; GFP, green fluorescent protein; GPCR, G protein-coupled receptor; GST, glutathione-S-transferase; HA, hemagglutinin; hADSC, human adipose tissue-derived mesenchymal stem cell; JNK, c-Jun N-terminal kinase; LPA, lysophosphatidic acid; LPC, lysophosphatidylcholine; MAP, mitogen-activated protein; MTT, 3-(4,5-dimethyl-2-thiozol)-2,5-diphenyl-2H-tetrazolium bromide; PTX, pertussis toxin; S1P, sphingosine-1-phosphate; SPC, sphingosylphosphorylcholine
