title: Interaction between monocytes and vascular smooth muscle cells enhances matrix metalloproteinase-1 production.
abstract: Matrix metalloproteinase-1 (MMP-1) plays an important role in atherosclerotic plaque rupture. The purpose of this study was to investigate the expression of MMP-1 by cell-to-cell interactions between monocytes and vascular smooth muscle cells (VSMCs). Human VSMCs and THP-1 cells (human monocytoid cells) were cocultured. MMP-1 levels were measured by enzyme-linked immunosorbent assay. Collagenolytic activity was determined by fluorescent labeled-collagen digestion. Immunohistochemistry was performed to determine which types of cells produce MMP-1. Adding THP-1 cells to VSMCs markedly increased the MMP-1 levels and activity of the culture media. MMP-1 levels were maximal when the cellular ratio of THP-1 cells/VSMCs was 1.0. Immunohistochemistry revealed that both types of cells in the coculture produced MMP-1. Separated coculture experiments showed that both direct contact and a soluble factor(s) contributed to MMP-1 production. Neutralizing anti-interleukin (IL)-6 and tumor necrosis factor-alpha antibodies inhibited coculture conditioned medium-induced MMP-1 production by VSMCs and THP-1 cells. Protein kinase C inhibitors, tyrosine kinase inhibitors, and a mitogen-activated protein kinase inhibitor significantly inhibited MMP-1 production by cocultures. Direct cell-to-cell interaction between THP-1 cells and VSMCs enhanced MMP-1 synthesis in both types of cells. Increased local MMP-1 production and activity induced by monocyte-VSMC interaction play an important pathogenic role in atherosclerotic plaque rupture.
authors.affiliation: Department of Cardiology, Jichi Medical School, Tochigi, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhu
authors.forename: Y
authors.initials: Y
authors.lastname: Hojo
authors.forename: U
authors.initials: U
authors.lastname: Ikeda
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
authors.forename: K
authors.initials: K
authors.lastname: Shimada
mesh_terms: D002448:Cell Adhesion / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D018920:Coculture Techniques; D003094:Collagen / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007202:Indicators and Reagents; D007375:Interleukin-1 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D020781:Matrix Metalloproteinase 1 / Q000096:biosynthesis*; D009000:Monocytes / Q000201:enzymology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000201:enzymology*; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D007202:Indicators and Reagents; D007375:Interleukin-1; D015850:Interleukin-6; D019715:Tissue Inhibitor of Metalloproteinase-1; D014409:Tumor Necrosis Factor-alpha; D003094:Collagen; D020781:Matrix Metalloproteinase 1