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Activated isoforms of MMP‐2 are induced in U87 human glioma cells in response to β‐amyloid peptide

Prior studies using rat primary hippocampal cultures indicated induction of matrix metalloproteinases (MMPs) in response to β‐amyloid (Aβ). Hence, it was of interest to determine whether MMP activity in a human cell line is influenced by Aβ. Aβ, but not interleukin‐1β (IL‐1β) or lipopolysaccharide (LPS), stimulated an active form of MMP‐2 in human U87 glioblastoma cells, as well as increased the expression of the well‐known activator of MMP‐2, membrane‐type (MT)‐MMP. Activation experiments carried out with amino phenyl mercuric acetate (APMA), immunoprecipitation, as well as immunoblotting, suggest that the lower molecular weight, gelatin‐degrading activity was an activated form of MMP‐2. Furthermore, it was demonstrated that a synthetic furin convertase inhibitor, decanoyl‐Arg‐Val‐Lys‐Arg‐chloromethylketone, decreased the production of Aβ‐induced active MMP‐2 in U87 cells. The induction of MMP‐3 by cytokines, but not by Aβ, suggests that the effect of Aβ on MMP‐2 is selective. Although Aβ stimulated tissue inhibtor of metalloproteinase‐1 (TIMP‐1), there was no obvious effect of Aβ on TIMP‐2 production in U87 cells. These results demonstrate that Aβ induces an active form of MMP‐2 likely by increasing the expression of MT‐MMP in a human glioblastoma cell line. Active MMP‐2 may degrade Aβ or act on ECM components critical in neuronal survival mechanisms and possibly play a role in Alzheimer's disease (AD) neuropathology. J. Neurosci. Res. 55:44–53, 1999.  © 1999 Wiley‐Liss, Inc.