Tissue Inhibitor of Metalloproteinase-3 Induces a Fas-associated Death Domain-dependent Type II Apoptotic Pathway

Mark Bond,Gillian Murphy,Martin R Bennett,Andrew C Newby,Andrew H Baker

doi:10.1074/jbc.m111507200

Abstract

Tissue inhibitors of metalloproteinases (TIMPs) are important regulators of matrix metalloproteinase (MMP) and adamalysin metalloproteinase activity. We previously reported that overexpression of TIMP-3 inhibits MMPs and induces apoptotic cell death in a variety of cell types and demonstrated that apoptosis is mediated through the N terminus of TIMP-3, which harbors the MMP inhibitory domain. However, little is known about the mechanisms underlying TIMP-3-induced apoptosis. Here we demonstrate that overexpression of TIMP-3 induced activation of initiator caspase-8 and -9 and promoted caspase-mediated cleavage of the death substrates poly(ADP-ribose) polymerase and focal adhesion kinase. Furthermore, TIMP-3 induced mitochondrial activation as demonstrated by loss of mitochondrial membrane potential and release of cytochrome c. Intervention studies demonstrated that overexpression of Bcl-2, the anti-apoptotic mitochondrial membrane protein, or CrmA, a viral serpin inhibitor of caspase-8, completely inhibited TIMP-3-induced apoptosis. Furthermore, a dominant-negative Fas-associated death domain mutant inhibited TIMP-3-induced death substrate cleavage and apoptotic death. Taken together, these results indicate that TIMP-3 overexpression induces a type II apoptotic pathway initiated via a Fas-associated death domain-dependent mechanism.

Highlights

Tissue inhibitors of metalloproteinases (TIMPs) are important regulators of matrix metalloproteinase (MMP) and adamalysin metalloproteinase activity
We previously reported that overexpression of TIMP-3 inhibits MMPs and induces apoptotic cell death in a variety of cell types and demonstrated that apoptosis is mediated through the N terminus of TIMP-3, which harbors the MMP inhibitory domain
Using adenovirus-mediated gene transfer, we recently demonstrated that overexpression of TIMP-3 in human vascular smooth muscle cells and cancer cell cultures reduces cell migration and promotes apoptotic cell death, the latter being evoked through an unknown mechanism [19, 20]

Summary

Introduction

Tissue inhibitors of metalloproteinases (TIMPs) are important regulators of matrix metalloproteinase (MMP) and adamalysin metalloproteinase activity. Using adenovirus-mediated gene transfer, we recently demonstrated that overexpression of TIMP-3 in human vascular smooth muscle cells and cancer cell cultures reduces cell migration and promotes apoptotic cell death, the latter being evoked through an unknown mechanism [19, 20]. This unique phenotype induced by TIMP-3 translates to a beneficial reduction in vascular neointima formation in a human model of late vein graft failure [21]. It is important to define the mechanism(s) through which TIMP-3 regulates apoptotic mediators when overexpressed

Methods

Results

Conclusion