Open AccessFurin-Like Proprotein Convertases Are Central Regulators of the Membrane Type Matrix Metalloproteinase–Pro-Matrix Metalloproteinase-2 Proteolytic Cascade in Atherosclerosis
Author(s) -
Philipp Stawowy,
Heike Meýborg,
D Stibenz,
Núbia Borges Pereira Stawowy,
Mattias Roser,
Usan Thanabalasingam,
John P. Veinot,
Michel Chrétien,
Nabil G. Seidah,
Eckart Fleck,
Kristof Graf
Publication year - 2005
Publication title -
circulation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.795
H-Index - 607
eISSN - 1524-4539
pISSN - 0009-7322
DOI - 10.1161/circulationaha.104.502617
Subject(s) - furin , proprotein convertases , metalloproteinase , matrix metalloproteinase , medicine , microbiology and biotechnology , proprotein convertase , proteolytic enzymes , biochemistry , enzyme , lipoprotein , biology , cholesterol , ldl receptor
Background— Accumulation of macrophages and their in situ expression of matrix metalloproteinases (MMPs) are important determinants of plaque stability. Activation of membrane-bound MT1-MMP, the major activator of pro-MMP-2, requires intracellular endoproteolytic cleavage of its precursor protein. This type of activation typically requires suitable furin-like proprotein convertases (PCs), specifically furin and PC5. The present study was done to investigate the function of MT1-MMP as well as furin-like PCs in mononuclear inflammatory cells.Methods and Results— Macrophage differentiation of human monocytic THP-1 cells was accompanied by increased expression of furin, PC5, and MT1-MMP. Some pro-MMP-2 activation was found in macrophages, but pro-MMP-2 level or activation was not enhanced after stimulation with the proinflammatory mediators tumor necrosis factor-α or lipopolysaccharide. However, culturing of macrophages in conditioned medium from serum-starved vascular smooth muscle cells, which constitutively secrete pro-MMP-2, resulted in a strong pro-MMP-2 activation. Inhibition of furin-like PCs with the specific pharmacological inhibitor decanoyl-RVKR-chloromethylketone (dec-CMK) inhibited MT1-MMP activation in macrophages. Dec-CMK or furin-specific small interfering RNA significantly inhibited macrophage MT1-MMP–dependent activation of vascular smooth muscle cell–derived pro-MMP-2. Flow cytometry demonstrated that human circulating monocytes express furin and PC5, and MT1-MMP and immunohistochemistry revealed their colocalization in macrophages in advanced human atherosclerotic lesions.Conclusions— Furin-like PCs (furin and PC5) play a central role in a MT-MMP–MMP-2 proteolytic cascade, involving provision of macrophage MT1-MMP for the activation of pro-MMP-2 synthesized by other cells. Furin and PC5 are expressed in human peripheral blood mononuclear cells and colocalize with MT1-MMP in macrophages in the atherosclerotic plaque, supporting the hypothesis that they are potential targets in atherosclerosis.