Role for matrix metalloproteinase-2 in oxidized low-density lipoprotein-induced activation of the sphingomyelin/ceramide pathway and smooth muscle cell proliferation.
BACKGROUND
Oxidized LDLs (oxLDLs) and matrix metalloproteinases (MMPs) are present in atherosclerotic lesions. OxLDLs activate various signaling pathways potentially involved in atherogenesis. OxLDLs induce smooth muscle cell (SMC) proliferation mediated by the activation of the sphingomyelin/ceramide pathway and tyrosine kinase receptors. MMPs are also able to induce SMC migration and proliferation in addition to extracellular matrix degradation. The present study was designed to investigate whether MMPs play a role in the mitogenic effect of oxLDLs.


RESULTS
OxLDLs induce the release of activated MMP-2 in SMC culture medium. MMP-2 was identified by its 65-kDa gelatinase activity on zymography and by using specific blocking antibodies and MMP-2-/- cells. MMP inhibitors (batimastat and Ro28-2653) and the blocking antibodies anti-MMP-2 and anti-membrane type 1-MMP inhibited the oxLDL-induced sphingomyelin/ceramide pathway activation and subsequent activation of ERK1/2 and DNA synthesis but did not inhibit the oxLDL-induced epidermal growth factor receptor and platelet-derived growth factor receptor activation. Exogenously added activated MMP-2 or membrane type 1-MMP-1 triggered the activation of both sphingomyelin/ceramide and ERK1/2 pathways and DNA synthesis. Conversely, suppression of MMP-2 expression in MMP-2-/- cells or in SMCs treated by small-interference RNA also blocked both sphingomyelin/ceramide signaling and DNA synthesis.


CONCLUSIONS
Together, these data demonstrate that MMP-2 plays a pivotal role in oxLDL-induced activation of the sphingomyelin/ceramide signaling pathway and subsequent SMC proliferation. These pathways may constitute a potential therapeutic target for modulating the oxLDL-induced proliferation of SMCs in atherosclerosis or restenosis.
Augé
Nathalie
N
INSERM U-466, Department of Biochemistry, CHU Rangueil, Toulouse, France.
Maupas-Schwalm
Françoise
F
Elbaz
Meyer
M
Thiers
Jean-Claude
JC
Waysbort
Axel
A
Itohara
Shigeyoshi
S
Krell
Hans-Willi
HW
Salvayre
Robert
R
Nègre-Salvayre
Anne
A
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D002518:Ceramides / Q000502:physiology; D004261:DNA Replication / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D066246:ErbB Receptors / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D008246:Lysophospholipids / Q000502:physiology; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D061965:Matrix Metalloproteinase Inhibitors; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000494:pharmacology / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D019950:Mitogen-Activated Protein Kinase 1 / Q000502:physiology; D048052:Mitogen-Activated Protein Kinase 3 / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000378:metabolism; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000494:pharmacology; D011817:Rabbits; D017479:Receptors, Platelet-Derived Growth Factor / Q000187:drug effects; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects*; D013108:Sphingomyelin Phosphodiesterase / Q000378:metabolism; D013109:Sphingomyelins / Q000502:physiology; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000502:physiology; D013876:Thiophenes / Q000494:pharmacology
D002518:Ceramides; D008077:Lipoproteins, LDL; D008246:Lysophospholipids; D061965:Matrix Metalloproteinase Inhibitors; D010879:Piperazines; D011480:Protease Inhibitors; D011743:Pyrimidines; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; C453902:Ro 28-2653; D013109:Sphingomyelins; D013876:Thiophenes; C099252:oxidized low density lipoprotein; C060506:sphingosine 1-phosphate; D010649:Phenylalanine; C080985:batimastat; D066246:ErbB Receptors; D017479:Receptors, Platelet-Derived Growth Factor; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D013108:Sphingomyelin Phosphodiesterase; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2; D013110:Sphingosine