Matrix Metalloproteinase-3 Is Increased and Participates in Neuronal Apoptotic Signaling Downstream of Caspase-12 during Endoplasmic Reticulum Stress

Abstract

Although endoplasmic reticulum (ER) stress-induced apoptosis has been associated with pathogenesis of neurodegenerative diseases, the cellular components involved have not been well delineated. The present study shows that matrix metalloproteinase (MMP)-3 plays a role in the ER stress-induced apoptosis. ER stress induced by brefeldin A (BFA) or tunicamycin (TM) increases gene expression of MMP-3, selectively among various MMP subtypes, and the active form of MMP-3 (actMMP-3) in the brain-derived CATH.a cells. Pharmacological inhibition of enzyme activity, small interference RNA-mediated gene knockdown, and gene knock-out of MMP-3 all provide protection against ER stress. MMP-3 acts downstream of caspase-12, because both pharmacological inhibition and gene knockdown of caspase-12 attenuate the actMMP-3 increase, but inhibition and knock-out of MMP-3 do not alter caspase-12. Furthermore, independently of the increase in the protein level, the catalytic activity of MMP-3 enzyme can be increased via lowering of its endogenous inhibitor protein TIMP-1. Caspase-12 causes liberation of MMP-3 enzyme activity by degrading TIMP-1 that is already bound to actMMP-3. TIMP-1 is decreased in response to ER stress, and TIMP-1 overexpression leads to cell protection and a decrease in MMP-3 activity. Taken together, actMMP-3 protein level and catalytic activity are increased following caspase-12 activation during ER stress, and this in turn plays a role in the downstream apoptotic signaling in neuronal cells. MMP-3 and TIMP-1 may therefore serve as cellular targets for therapy against neurodegenerative diseases. The endoplasmic reticulum (ER)2 is the organelle responsible for proper synthesis and folding of proteins as well as maintenance of intracellular calcium homeostasis. Various cellular stresses cause disruption of normal ER functions, leading to ER stress, and excessive and prolonged ER stress leads to accumulation of misfolded and/or unfolded proteins, and ultimately apoptosis (1).Neurons are particularly vulnerable to ER stress, and ample evidence exists in the literature that links ER stress with neurodegeneration (2-4). Therefore, identification of cellular components and elucidation of the sequence of events following ER stress in neuronal cells would be of great importance in understanding the mechanism of neurodegeneration. The molecular connection between the ER stress response and apoptotic signaling, however, is not clearly understood. Although caspase-12, residing outside of ER membrane, has been shown to be specifically involved in the apoptotic signaling that results from ER stress (5, 6), the exact mechanism by which this occurs has not been elucidated and immediate downstream targets of caspase-12 remain to be identified.Matrix metalloproteinase (MMP)-3 belongs to a family of MMP enzymes known to participate in degradation of components of the extracellular matrix. MMP-3 has been associated with pathogenesis of a number of diseases such as Alzheimer disease, Parkinson disease, stroke, brain trauma, neuroinfl...

Metalloproteinase-9 contributes to inflammatory glia activation and nigro-striatal pathway degeneration in both mouse and monkey models of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonism

“…Related to Parkinsonism, in vitro studies have demonstrated intracellular activation of MMP-3 after neuronal stress, with consequent induction of apoptotic-signaling cascades Kim et al 2010). MMP-3 released by dying neurons activates microglia, further contributing to neurodegeneration (Kim et al 2007) along with MMP-9 (Woo et al 2008).…”

PTX3 Controls Activation of Matrix Metalloproteinase 1 and Apoptosis in Conjunctivochalasis Fibroblasts

“…A high level of extracellular actMMP-1 and/or actMMP-3 might not only dissolve the extracellular matrix leading to CCh but also contribute to anoikis, which is a form of apoptosis because of interruption of cell-matrix adhesion. 41 Nonetheless, we could not ignore the role of intracellular actMMP-1 and actMMP-3, which have also been implicated to lead to cell death of cultured neurons and myocyte cells, 42,43 as well as cell DArgic neurons and hepatic myofibroblasts, 21,23,44 respectively. Because Aprotinin (an inhibitor of serine proteinase that is known to activate MMPs) 45 achieved the same extent of rescue as Batimastat (a competitive, reversible, and broad-spectrum inhibitor of MMPs, especially MMP-1) 46 and NNGH (an MMP-3-specific inhibitor), 23,24 we suspect that the action of PTX3 in controlling activation of MMP-1 and MMP-3 might reside not only at the transcriptional and translational levels but also post translational activation of MMPs.…”

“…Batimastat, an inhibitor of both MMP1 and MMP3, and centrifugal filter units were purchased from EMD Millipore (Billerica, MA). N-isobutyl-N-(4-methoxyphenylsulfonyl)-glycylhydroxamic acid (NNGH), a specific MMP-3 inhibitor, [22][23][24] was purchased from Enzo Life Sciences, Inc. (Farmingdale, NY). DeadEnd Fluorometric TUNEL System and RQ1 RNase-Free DNase were purchased from Promega (Madison, WI).…”

Metalloproteinases and Metalloproteinase Inhibitors in Age-Related Diseases

“…In addition, MMP-3 produced by the activated microglia can be released into the extracellular matrix, further exacerbating the neuroinflammatory process [324]. In contrast, overexpression of TIMP-1 results in the attenuation of apoptosis in neuronal cells, along with the suppression of MMP-3 activity [325]. TIMP-1 is also neuroprotective, both against excitotoxic neuronal death [326] and against traumatic and ischemic brain injury in mice [327].…”