Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Regulation of the extracellular matrix by proteases and protease inhibitors is a fundamental biological process for normal growth, development and repair in the CNS. Matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs) are the major extracellular-degrading enzymes. Two other enzyme families, a disintegrin and metalloproteinase (ADAM), and the serine proteases, plasminogen/plasminogen activator (P/PA) system, are also involved in extracellular matrix degradation. Normally, the highly integrated action of these enzyme families remodels all of the components of the matrix and performs essential functions at the cell surface involved in signaling, cell survival, and cell death. During the inflammatory response induced in infection, autoimmune reactions and hypoxia/ischemia, abnormal expression and activation of these proteases lead to breakdown of the extracellular matrix, resulting in the opening of the blood-brain barrier (BBB), preventing normal cell signaling, and eventually leading to cell death. There are several key MMPs and ADAMs that have been implicated in neuroinflammation: gelatinases A and B (MMP-2 and -9), stromelysin-1 (MMP-3), membrane-type MMP (MT1-MMP or MMP-14), and tumor necrosis factor-alpha converting enzyme (TACE). In addition, TIMP-3, which is bound to the cell surface, promotes cell death and impedes angiogenesis. Inhibitors of metalloproteinases are available, but balancing the beneficial and detrimental effects of these agents remains a challenge.
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PMID:Diverse roles of matrix metalloproteinases and tissue inhibitors of metalloproteinases in neuroinflammation and cerebral ischemia. 1862 Nov 8

As growth plate chondrocytes mature and hypertrophy, they reorganize their proteoglycan-rich type II collagen extracellular matrix (ECM), involving 1,25(OH)(2)D(3)-dependent regulation of matrix metalloproteinases (MMPs). Stromelysin-1 (MMP-3) and 72-kD gelatinase (MMP-2) are found in extracellular matrix vesicles (MVs) and release and activate ECM-bound latent TGF-beta1 and TGF-beta2, respectively. 1,25(OH)(2)D(3) regulates incorporation of MMP-2 and MMP-3 into MVs and release of these enzymes in the ECM. Plasma membranes (PMs) and MVs contain the 1alpha,25(OH)(2)D(3) membrane receptor ERp60 (protein disulfide isomerase A3), phospholipase A(2) (PLA(2)), PLA(2)-activating protein, the nuclear vitamin D receptor and caveolin-1. 1,25(OH)(2)D(3) secreted by chondrocytes binds MV ERp60, activating PLA(2). Resulting lysophospholipids destabilize MV membranes, releasing active MMPs. We examined 1,25(OH)(2)D(3)-dependent activation of latent TGF-beta1 stored in cartilage ECM. Interestingly, TGF-beta1 regulates 1,25(OH)(2)D(3) production. 1alpha,25(OH)(2)D(3) activates PM protein kinase C (PKC)-alpha via ERp60-dependent PLA(2)-signaling, lysophospholipid production and phospholipase C-gamma. It also regulates distribution of phospholipids and PKC isoforms between MVs and PMs, enriching MVs in PKC-zeta. Direct activation of MV MMP-3 requires ERp60 based on blocking antibodies and PKC based on inhibitor studies. However, treatment of MVs with 1,25(OH)(2)D(3) decreases MV PKC-zeta activity, suggesting more complex feedback mechanisms, potentially involving MV lipid signaling. Our observations indicate that one role of MVs is to provide MMPs at sites distant from the cells. Chondrocytes secrete 1,25(OH)(2)D(3), which acts directly on MV-membranes via ERp60, releasing MMPs. MMP-specific ECM components are hydrolyzed, resulting in release and activation of growth factors that can act back on the cells.
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PMID:1,25-Dihydroxy vitamin D3 is an autocrine regulator of extracellular matrix turnover and growth factor release via ERp60-activated matrix vesicle matrix metalloproteinases. 1876 31

Tissue-type plasminogen activator (t-PA) is approved for treatment of ischemic stroke patients, but it increases the risk of intracranial bleeding (ICB). Previously, we have shown in a mouse stroke model that stromelysin-1 (matrix metalloproteinase-3 [MMP-3]) induced in endothelial cells was critical for ICB induced by t-PA. In the present study, using bEnd.3 cells, a mouse brain-derived endothelial cell line, we showed that MMP-3 was induced by both ischemic stress and t-PA treatment. This induction by t-PA was prevented by inhibition either of low-density lipoprotein receptor-related protein (LRP) or of nuclear factor-kappaB activation. LRP was up-regulated by ischemic stress, both in bEnd.3 cells in vitro and in endothelial cells at the ischemic damage area in the mouse stroke model. Furthermore, inhibition of LRP suppressed both MMP-3 induction in endothelial cells and the increase in ICB by t-PA treatment after stroke. These findings indicate that t-PA deteriorates ICB via MMP-3 induction in endothelial cells, which is regulated through the LRP/nuclear factor-kappaB pathway.
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PMID:Tissue-type plasminogen activator (t-PA) induces stromelysin-1 (MMP-3) in endothelial cells through activation of lipoprotein receptor-related protein. 1981 79

A zinc-dependent matrix metalloproteinase (NtMMP1) found in the plasma membrane of Nicotiana tabacum cv. Bright Yellow 2 (BY-2) suspension cells is thought to be responsible for the degradation of recombinant proteins secreted into the culture supernatant. We have characterized the proteolytic activity of NtMMP1 by expressing a recombinant derivative lacking the C-terminal transmembrane domain in yeast. After purifying the protein by affinity chromatography, its autocatalytic activity was analyzed using monoclonal antibodies raised against its N-terminal and C-terminal portions. Both the unprocessed and processed forms of NtMMP1 displayed caseinolytic activity and N-terminal sequencing identified an autocatalytic cleavage site within the sequence motif HFSFFP, which is similar to the corresponding sequences of the human matrix metalloproteinases stromelysin-1 (MMP-3) and stromelysin-2 (MMP-10). Unlike all other matrix metalloproteinases investigated so far, NtMMP1 contains a disulfide bond within its propeptide thus rendering the proenzyme catalytically active. Kinetic analysis of NtMMP1 with a synthetic substrate revealed a K(m) of 10.55 +/- 0.9 microM, a k(cat) of 0.6 +/- 0.01 s(-1) and maximum activity at pH 7.5. We found that NtMMP1 degrades Desmodus rotundus salivary plasminogen activator alpha 1 (DSPAalpha1), a biopharmaceutical protein, that has proven difficult to produce in tobacco BY-2 cells. This provides a likely explanation for the frequent instability of secreted recombinant biopharmaceuticals produced in plant suspension cell cultures. Our data suggest new avenues that can be explored to improve the production of pharmaceutical proteins in plants and plant cells.
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PMID:Biochemical properties of the matrix metalloproteinase NtMMP1 from Nicotiana tabacum cv. BY-2 suspension cells. 2063 96


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