title: Matrix metalloproteinase-3 is activated by HtrA2/Omi in dopaminergic cells: relevance to Parkinson's disease.
abstract: Dopaminergic neurons in the substantia nigra are particularly vulnerable, and their degeneration leads to Parkinson's disease. We have previously reported that matrix metalloproteinase-3 (MMP-3) activity is involved in dopaminergic neurodegeneration by multiple mechanisms and that this requires activation of MMP-3 from proMMP-3 by an intracellular serine protease. HtrA2/Omi is a mitochondrial serine protease that has been shown in non-dopaminergic cells to translocate into the cytosol where it triggers apoptosis. In the present study we sought to determine whether HtrA2/Omi might cause activation of MMP-3 in dopaminergic neuronal cells using CATH.a cell line. Mitochondrial stress induced by rotenone led to MMP-3 activation and HtrA2/Omi translocation into the cytosol. The MMP-3 activation involved HtrA2/Omi, because both pharmacological inhibition and siRNA-induced knockdown of HtrA2/Omi attenuated the activation induced by rotenone or MPP+. Overexpression of mature HtrA2/Omi, but not mutant HtrA2/Omi, resulted in MMP-3 activity increase and cell death. Addition of recombinant and catalytically active HtrA2/Omi to lysate of untreated cells led to activation of the endogenous MMP-3, and incubation of the HtrA2/Omi with recombinant proMMP-3 caused cleavage of proMMP-3 to a 48kD protein, corresponding to the active form, which was accompanied by an increase in MMP-3 activity. Taken together, the data indicate that HtrA2/Omi, which normally exists in the mitochondria, can cause MMP-3 activation in the cytosol under a cell stress condition, which can ultimately lead to demise of dopaminergic neuronal cells.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul 138-736, Republic of Korea.
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Shin
authors.forename: Eun-Mee
authors.initials: EM
authors.lastname: Kim
authors.forename: Ji Ae
authors.initials: JA
authors.lastname: Lee
authors.forename: Hyangshuk
authors.initials: H
authors.lastname: Rhim
authors.forename: Onyou
authors.initials: O
authors.lastname: Hwang
mesh_terms: D015153:Blotting, Western; D016923:Cell Death; D003600:Cytosol / Q000187:drug effects / Q000201:enzymology; D059290:Dopaminergic Neurons / Q000201:enzymology*; D004789:Enzyme Activation / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D007770:L-Lactate Dehydrogenase / Q000032:analysis / Q000378:metabolism; D019278:Matrix Metalloproteinase 3 / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000502:physiology*; D010300:Parkinson Disease / Q000201:enzymology*; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D016601:RNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000502:physiology*; D060888:Real-Time Polymerase Chain Reaction; D012402:Rotenone / Q000494:pharmacology; D000068103:Serine-Arginine Splicing Factors; D016622:Silver Staining; D013347:Subcellular Fractions / Q000378:metabolism; D014162:Transfection; D014475:Uncoupling Agents / Q000494:pharmacology; D051636:X-Linked Inhibitor of Apoptosis Protein / Q000378:metabolism
chemical_list: D009419:Nerve Tissue Proteins; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; C097083:TRA2B protein, human; D014475:Uncoupling Agents; D051636:X-Linked Inhibitor of Apoptosis Protein; D012402:Rotenone; D000068103:Serine-Arginine Splicing Factors; D012313:RNA; D007770:L-Lactate Dehydrogenase; D019278:Matrix Metalloproteinase 3