Ceramide 1-phosphate stimulates macrophage proliferation through activation of the PI3-kinase/PKB, JNK and ERK1/2 pathways.
Ceramide 1-phosphate (C1P) was first shown to be mitogenic for fibroblasts, but the mechanisms whereby it stimulated cell proliferation have remained largely unknown. Here we demonstrate that C1P stimulates DNA synthesis and cell division in murine bone marrow-derived macrophages. C1P caused rapid phosphorylation of protein kinase B (PKB, also known as Akt), a downstream target of phosphatidylinositol 3-kinase (PI3-K). Selective inhibition of PI3-K blocked both DNA synthesis and cell growth. C1P induced phosphorylation of GSK-3beta, which is a major target of PKB, and this effect was also abolished by inhibition of PI3-K. In addition, C1P upregulated the expression of cyclin D1 and c-Myc, two major targets of GSK-3beta, which are important regulators of cell proliferation. C1P stimulated the activity of NF-kappaB, and inhibitors of this transcription factor completely blocked macrophage proliferation. Lastly, C1P induced phosphorylation of the mitogen activated protein kinases (MAPK) extracellularly regulated kinases 1 and 2 (ERK1/2), and c-Jun N-terminal kinase (JNK). Inhibition of ERK1/2 and JNK also blocked C1P-induced macrophage proliferation. It can be concluded that C1P stimulates macrophage proliferation through activation of the PI3-K/PKB, ERK and JNK pathways, and that GSK-3beta, c-Myc, cyclin D1, and NF-kappaB are important downstream effectors in this action.
Gangoiti
Patricia
P
Department of Biochemistry and Molecular Biology, University of the Basque Country, P.O. Box 644, 48080 Bilbao, Spain.
Granado
María H
MH
Wang
Shih Wei
SW
Kong
Jennifer Y
JY
Steinbrecher
Urs P
UP
Gómez-Muñoz
Antonio
A
D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D002518:Ceramides / Q000378:metabolism*; D056741:Cyclin D; D016213:Cyclins / Q000378:metabolism; D004261:DNA Replication; D004789:Enzyme Activation; D005260:Female; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors
D002518:Ceramides; D056741:Cyclin D; D016213:Cyclins; D038362:Glycogen Synthase Kinase 3; D000071679:Glycogen Synthase Kinase 3 beta; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D016328:NF-kappa B; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D016271:Proto-Oncogene Proteins c-myc; C489428:Myc protein, mouse; C065576:ceramide 1-phosphate; C000605507:Gsk3b protein, mouse