title: MAPK signaling regulates endothelial cell assembly into networks and expression of MT1-MMP and MMP-2.
abstract: Microvascular endothelial cells embedded within three-dimensional (3D) type I collagen matrixes assemble into cellular networks, a process that requires the upregulation of membrane type 1 (MT1) matrix metalloproteinase (MMP) and MMP-2. The purpose of this study was to identify the signaling pathways responsible for the transcriptional activation of MT1-MMP and MMP-2 in endothelial cells in 3D collagen lattices. We hypothesized that the 3D type I collagen induction of MT1-MMP and MMP-2 is mediated by the mitogen-activated protein kinase family of enzymes. Here, we show that 3D type I collagen elicits a persistent increase in ERK1/2 and JNK activation and a decrease in p38 activation. Inhibition of ERK1/2 or JNK disrupted endothelial network formation in 3D type I collagen lattices, whereas inhibition of p38 promoted network formation. mRNA levels of both MT1-MMP and MMP-2 were attenuated by ERK1/2 inhibition but unaffected by either JNK or p38 inhibition. By contrast, expression of constitutively active MEK was sufficient to stimulate MMP-2 production in a monolayer of endothelial cells cultured on type I collagen. These results provide evidence that signaling through both ERK1/2 and JNK regulates endothelial assembly into cellular networks but that the ERK1/2 signaling cascade specifically regulates network formation and the production of both MT1-MMP and MMP-2 genes in response to 3D type I collagen.
authors.affiliation: School of Kinesiology and Health Sciences, Farquharson Bldg., Rm. 341, York University, 4700 Keele St., Toronto, Ontario, Canada M3J 1P3.
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Boyd
authors.forename: Jennifer
authors.initials: J
authors.lastname: Doyle
authors.forename: Eric
authors.initials: E
authors.lastname: Gee
authors.forename: Shelley
authors.initials: S
authors.lastname: Pallan
authors.forename: Tara L
authors.initials: TL
authors.lastname: Haas
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques / Q000379:methods; D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D051766:Early Growth Response Protein 1; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism*; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D017874:Immediate-Early Proteins / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000502:physiology*; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism*; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D024042:Collagen Type I; D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; D017874:Immediate-Early Proteins; D014157:Transcription Factors; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D020930:MAP Kinase Kinase Kinases; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2