UNIPROT:P43026 - FACTA Search

Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Evidence presented in the accompanying article (Gibbs, D. F., T. P. Shanley, R. L. Warner, H. S. Murphy, J. Varani, and K. J. Johnson. 1999. Role of matrix metalloproteinases in models of macrophage-dependent acute lung injury: evidence for alveolar macrophage as source of proteinases. Am. J. Respir. Cell Mol. Biol. 20:1145-1154) implicates alveolar macrophage matrix metalloproteinases (MMPs) in two models of acute lung inflammation in the rat. As a prerequisite to understanding which specific MMPs might be involved in the injury and how they might function, it was necessary to know the spectrum of enzymes present. To this end, alveolar macrophages were obtained from normal rat lungs by bronchoalveolar lavage, placed in culture with and without various agonists, and assessed by a variety of techniques for MMPs. The identification process involved characterization by gelatin, beta-casein, and kappa-elastin zymography, with confirmation of identity by Western blot/immunoprecipitation. Message levels of detected MMPs were assessed by Northern blot. Rat alveolar macrophages were found to produce a low constitutive level of MMP-2 (72-kD gelatinase A) that was only modestly upregulated following stimulation with phorbol myristate acetate, bacterial lipopolysaccharide, or immunoglobulin A-containing immune complexes. Although control cells were found to produce little or no MMP-9 (92-kD gelatinase B) or MMP-12 (metalloelastase), both enzymes were markedly upregulated upon stimulation. In the same stimulated macrophages there was little activity against type I collagen (associated with MMP-13 [collagenase-3] on the basis of Western blotting), no activity suggestive of stromelysin or matrilysin, and no measurable secretion of the serine proteinases, elastase and cathepsin G. These data demonstrate the ability of rat alveolar macrophages to elaborate certain MMPs under proinflammatory conditions, consistent with their possible involvement in the progression of acute inflammation.
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PMID:Characterization of matrix metalloproteinases produced by rat alveolar macrophages. 1034 Sep 32

Chlamydia pneumoniae, an intracellular Gram-negative respiratory bacterium, and macrophages are present in inflammatory tissue sites such as atherosclerotic lesions, where abnormal degradation of the extracellular matrix takes place. To evaluate the potential of C pneumoniae for participation in matrix destruction, we studied the effect of this bacterium on the production of 3 matrix-degrading metalloproteinases, 92-kDa gelatinase, interstitial collagenase-1, and stromelysin-1, and their natural inhibitor TIMP-1 (tissue inhibitor of metalloproteinases-1) by human monocyte-derived macrophages differentiated in vitro. Spontaneous production of collagenase and stromelysin by these cells was minimal and was not influenced by C pneumoniae. In contrast, the cells secreted substantial basal quantities of 92-kDa gelatinase, the secretion of which was stimulated (on average, 2.5-fold) by C pneumoniae. C pneumoniae regulated the expression of 92-kDa gelatinase by macrophages at the pretranslational level. Macrophages secreted only small quantities of TIMP-1. The chlamydial proteins Omp2, MOMP, and HSP60 were also found to participate in the induction of 92-kDa gelatinase by C pneumoniae. Denaturation of chlamydial proteins by boiling reduced 92-kDa gelatinase secretion only partially (by 35%), suggesting that the heat-stabile lipopolysaccharide molecules also stimulate secretion of the enzyme. The results show that production of 92-kDa gelatinase by human macrophages is selectively upregulated by C pneumoniae, which suggests that these bacteria, when present in a macrophage-containing inflammatory environment, actively participate in the destruction of the extracellular matrix.
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PMID:Chlamydia pneumoniae proteins induce secretion of the 92-kDa gelatinase by human monocyte- derived macrophages. 1114 52

Reperfusion damages the blood-brain barrier (BBB). Matrix metalloproteinases (MMPs) are associated with the opening of the BBB, but their cellular localization and activation mechanisms are uncertain. We used immunohistochemistry to determine the cellular localization of the MMPs in reperfused rat brain, and cell cultures to study their activation. Spontaneously hypertensive rats (SHR) had a 90 min middle cerebral artery occlusion (MCAO) followed by reperfusion for times from 3 h to 21 days. Frozen sections were immunostained with antibodies to gelatinase A (MMP-2), stromelysin-1 (MMP-3), and gelatinase B (MMP-9). Sham-operated control rats showed MMP-2 immunostaining in astrocytic processes next to blood vessels. After 3 h of the onset of reperfusion MMP-2 immunostaining increased in astrocytes. At 24 h immunoreactivity for MMP-3 and MMP-9 appeared. MMP-3 co-localized with activated microglia (Ox-42+) and ischemic neurons (NeuN+). MMP-9 immunostaining was seen at 48 h in endothelial cells, neutrophils, and neurons. At 5 and 21 days intense MMP-2 staining was seen in reactive astrocytes around the ischemic core. Studies of activation of the MMP were done in lipopolysaccharide (LPS)-stimulated astrocyte and microglia cultures. Stimulated astrocytes produced an activated form of MMP-2. When microglia were stimulated, they activated MMP-9. Immunostaining showed MMP-3 in cultures of enriched microglial cells. The hydroxymate-type, MMP inhibitor, BB-1101, blocked the activation of MMP-2 and MMP-9 by LPS in mixed glial cultures. We propose that MMP-2 is normally present in astrocytic end feet, and that during ischemia MMP-9 and MMP-3 are produced. MMP-3 in microglia/macrophages may be activating proMMP-9. Our results show that a differential expression of MMPs by astrocytes, microglia, and endothelial cells at the blood vessels is involved in the proteolytic disruption of the BBB.
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PMID:Immunohistochemistry of matrix metalloproteinases in reperfusion injury to rat brain: activation of MMP-9 linked to stromelysin-1 and microglia in cell cultures. 1122 98

The cause of persistent arthritis in patients with Lyme disease who have received standard antibiotic therapy remains an area of debate. In this study, synovial fluid levels of matrix metalloproteinases (MMPs) were compared in persons with untreated and antibiotic-resistant Lyme arthritis. Levels of MMP-1 and MMP-3, as determined by ELISA, were higher in untreated patients (P=.0064 and P=.002, respectively), whereas levels of MMP-8 and MMP-9 were higher in antibiotic-resistant patients (P=.0002 and P=.0014, respectively). In vitro studies of chondrocyte cultures infected with Borrelia burgdorferi revealed induction of MMP-1 and MMP-3 but not of MMP-8 or MMP-9. Neither Staphylococcus aureus nor lipopolysaccharide stimulated MMP-1 or MMP-3 release from these cells. The mechanism of recognition of B. burgdorferi may be through CD14 and toll-like receptor-2, which were up-regulated in the presence of B. burgdorferi. These findings suggest different stimuli for MMP induction in untreated and antibiotic-resistant Lyme arthritis.
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PMID:Differences in synovial fluid levels of matrix metalloproteinases suggest separate mechanisms of pathogenesis in Lyme arthritis before and after antibiotic treatment. 1142 14

Neuroinflammation induces a complex molecular cascade that leads to the proteolysis of cells. Matrix metalloproteinases (MMPs) attack all components of the extracellular matrix in a number of neuroinflammatory diseases and cause a delayed opening of the blood-brain barrier (BBB). Earlier, we showed that lipopolysaccharide (LPS) disrupted the BBB through the action of gelatinase B (MMP-9). In a study of cerebral ischemia, gelatinase A (MMP-2) was seen in astrocytic end-feet and stromelysin-1 (MMP-3) in microglia. Since other MMPs may be important in LPS-induced injury, we studied the gene transcription and cellular localization of several MMPs and an inflammatory mediator, tumor necrosis factor (TNF-alpha), using competitive polymerase chain reaction (PCR) and immunohistochemical methods. Significantly elevated levels of MMP-2 and -3 mRNA were observed in LPS-injected brains by 2 h after injection as compared to non-injected brain tissue (P<0.05). By 8 h post-LPS injection, gene expression of MMP-2 and -3 had declined in both saline- and LPS-injected tissue, while TNF-alpha mRNA levels rose significantly. Immunohistochemistry of control brains confirmed the earlier observation of MMP-2 immunoreactivity in processes abutting cerebral blood vessels, which increased after LPS injection. The expression of MMP-9 and MMP-3 was localized mainly to the cerebrovasculature in LPS-stimulated brain tissue, predominantly in the perivascular cells of the basal lamina near the site of injection. Both of these proteinases were present at the site of LPS injection at 8 h, but MMP-2 was absent. Our results show that MMP genes are up-regulated prior to the induction of cytokines such as TNF-alpha, and that MMP proteins are prominent around blood vessels in LPS-induced neuroinflammation.
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PMID:Stromelysin-1 and gelatinase A are upregulated before TNF-alpha in LPS-stimulated neuroinflammation. 1192 34

Morphological changes observed in OA include cartilage erosion as well as a variable degree of synovial inflammation. Current research attributes these changes to a complex network of biochemical factors, including proteolytic enzymes, that lead to a breakdown of the cartilage macromolecules. Cytokines such as IL-1 and TNF-alpha produced by activated synoviocytes, mononuclear cells or by articular cartilage itself significantly up-regulate metalloproteinases (MMP) gene expression. Cytokines also blunt chondrocyte compensatory synthesis pathways required to restore the integrity of the degraded extrecellular matrix (ECM). Moreover, in OA synovium, a relative deficit in the production of natural antagonists of the IL-1 receptor (IL-1Ra) has been demonstrated, and could possibly be related to an excess production of nitric oxide in OA tissues. This, coupled with an upregulation in the receptor level, has been shown to be an additional enhancer of the catabolic effect of IL-1 in this disease.IL-1 and TNF-alpha significantly up-regulate MMP-3 steady-state mRNA derived from human synovium and chondrocytes. The neutralization of IL-1 and/or TNF-alpha up-regulation of MMP gene expression appears to be a logical development in the potential medical therapy of OA. Indeed, recombinant IL-1receptor antagonists (ILRa) and soluble IL-1 receptor proteins have been tested in both animal models of OA for modification of OA progression. Soluble IL-1Ra suppressed MMP-3 transcription in the rabbit synovial cell line HIG-82. Experimental evidence showing that neutralizing TNF-alpha suppressed cartilage degradation in arthritis also support such strategy. The important role of TNF-alpha in OA may emerge from the fact that human articular chondrocytes from OA cartilage expressed a significantly higher number of the p55 TNF-alpha receptor which could make OA cartilage particularly susceptible to TNF-alpha degradative stimuli. In addition, OA cartilage produces more TNF-alpha and TNF anglealpha convertase enzyme (TACE) mRNA than normal cartilage. By analogy, an inhibitor to the p55 TNF-alpha receptor may also provide a mechanism for abolishing TNF-alpha-induced degradation of cartilage ECM by MMPs. Since TACE is the regulator of TNF-alpha activity, limiting the activity of TACE might also prove efficacious in OA. IL-1 and TNF-alpha inhibition of chondrocyte compensatory biosynthesis pathways which further compromise cartilage repair must also be dealt with, perhaps by employing stimulatory agents such as transforming growth factor-beta or insulin-like growth factor-I. Certain cytokines have antiinflammatory properties. Three such cytokines - IL-4, IL-10, and IL-13 - have been identified as able to modulate various inflammatory processes. Their antiinflammatory potential, however, appears to depend greatly on the target cell. Interleukin-4 (IL-4) has been tested in vitro in OA tissue and has been shown to suppress the synthesis of both TNF-alpha and IL-1beta in the same manner as low-dose dexamethasone. Naturally occurring antiinflammatory cytokines such as IL-10 inhibit the synthesis of IL-1 and TNF-alpha and can be potential targets for therapy in OA. Augmenting inhibitor production in situ by gene therapy or supplementing it by injecting the recombinant protein is an attractive therapeutic target, although an in vivo assay in OA is not available, and its applicability has yet to be proven. Similarly, IL-13 significantly inhibits lipopolysaccharide (LPS)-induced TNF-alpha production by mononuclear cells from peripheral blood, but not in cells from inflamed synovial fluid. IL-13 has important biological activities: inhibition of the production of a wide range of proinflammatory cytokines in monocytes/macrophages, B cells, natural killer cells and endothelial cells, while increasing IL-1Ra production. In OA synovial membranes treated with LPS, IL-13 inhibited the synthesis of IL-1beta, TNF-alpha and stromelysin, while increasing IL-1Ra production.In summary, modulation of cytokines that control MMP gene up-regulation would appear to be fertile targets for drug development in the treatment of OA. Several studies illustrate the potential importance of modulating IL-1 activity as a means to reduce the progression of the structural changes in OA. In the experimental dog and rabbit models of OA, we have demonstrated that in vivo intraarticular injections of the IL-Ra gene can prevent the progression of structural changes in OA. Future directions in the research and treatment of osteoarthritis (OA) will be based on the emerging picture of pathophysiological events that modulate the initiation and progression of OA.
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PMID:The role of cytokines in osteoarthritis pathophysiology. 1208 86

Recent studies have demonstrated important pro-inflammatory roles for two matrix metalloproteinases (MMPs)-MMP-3 (stromelysin-1) and MMP-9 (gelatinase B)-in acute lung injury [Am. J. Respir. Cell Mol. Biol. 24 (2001) 1]. A role for MMP-3 in skin inflammation has also been demonstrated [Proc. Natl. Acad. Sci. U. S. A. 96 (1999) 6885]. While leukocytes (neutrophils and macrophages) are known to elaborate these tissue-destructive enzymes, parenchymal cells are also capable of synthesizing MMPs. In the present study, we examined the production of MMP-3 and MMP-9 by rodent lung fibroblasts, type II epithelial cells, and vascular endothelial cells. Dermal fibroblasts were also examined. Cells were examined under control conditions and in response to agonists that induce acute inflammatory tissue injury (IgG-containing immune complexes and lipopolysaccharide [LPS]). In the absence of stimulation, MMP-3 and MMP-9 were not detected or were present at low level. However, upon stimulation with either of the two pro-inflammatory agonists, production of both enzymes occurred in fibroblasts and epithelial cells (though not in endothelial cells). The observation that resident cells in the tissue parenchyma can elaborate MMPs in direct response to pro-inflammatory stimuli provides insight into possible mechanisms by which tissue damage occurs in acute inflammation.
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PMID:Matrix metalloproteinases in acute inflammation: induction of MMP-3 and MMP-9 in fibroblasts and epithelial cells following exposure to pro-inflammatory mediators in vitro. 1512

There is much evidence that degradation of the extracellular matrix is essential for the development of cholesteatomas and that this is induced by activation of matrix metalloproteinases (MMPs). Vitamin D3 (VD3) has several well-recognised biological activities, including suppression of MMP production. The present study, therefore, was undertaken to examine whether VD3 could suppress MMP production from cholesteatoma keratinocytes in vitro. Keratinocytes (2.5 x 10(5) cells/mL) induced from cholesteatoma tissue specimens were cultured with various concentrations of VD3. After one hour, lipopolysaccharide was added to the cell cultures at 100 mug/mL. The culture supernatants were then collected and assayed for MMP-1 and MMP-3 by ELISA. We also used ELISA to measure the levels of both TIMP (tissue inhibitor of metalloproteinase)-1 and TIMP-2 in culture supernatants. Addition of VD3 into keratinocyte cultures caused the suppression of MMP and TIMP production, which was increased by LPS stimulation. This was dose-dependent. The present results showing the suppressive activity of VD3 on the production of MMPs, which are responsible for tissue remodeling, strongly suggest that VD3 would be a good candidate for an agent in the medical treatment of, or prophylaxis for, cholesteatomas.
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PMID:Suppressive activity of vitamin D3 on matrix metalloproteinase production from cholesteatoma keratinocytes in vitro. 1619 70

Blood-brain barrier (BBB) opening is mediated by matrix metalloproteinases (MMPs) in neuroinflammation. We tested the hypothesis that MMP-3 plays a role in BBB damage, using MMP-3 knockout (KO) mice and lipopolysaccharide (LPS)-induced opening of the BBB. We found less disruption of the BBB after intracerebral LPS injection in MMP-3 KO mice than in wild type (P<0.0006). MMP-3 KO mice had less MMP-9 than WT mice but similar levels of activation. Moreover, MMP-9 mRNA levels were increased to a similar level in both the MMP-3 KO and WT, suggesting both endogenous and exogenous sources. Unbiased stereology showed increased neutrophil counts in the brains of MMP-3 WT compared to KO mice. Degradation of tight junction proteins, claudin-5 and occludin, and the basal lamina protein, laminin-alpha1, was less affected in the KO than in the WT. Our results provide the first in vivo evidence that MMP-3 attacks the basal lamina and tight junction proteins, opening the BBB, thereby facilitating neutrophil influx.
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PMID:Blood-brain barrier disruption by stromelysin-1 facilitates neutrophil infiltration in neuroinflammation. 1662 62

An imbalance in the matrix metalloproteinase (MMP) : tissue inhibitor of MMP (TIMP) ratio may be associated with tissue injury. Here, we studied the regulation of TIMP and MMP gene expression in primary glial cultures to ascertain the factors involved in the regulation of these genes in conditions of inflammatory neuropathology. Astrocytes were found to basally express TIMP-1 and TIMP-3 mRNA while microglia expressed only TIMP-2 mRNA. TIMP-4 mRNA was not detectable in either cell type. Treatment with interferon-alpha (IFN-alpha), IFN-gamma, interleukin-3 (IL-3), IL-6 or tumor necrosis factor-alpha (TNF-alpha) did not alter expression of the TIMP genes. However, in astrocytes, but not in microglia, serum, IL-1beta or lipopolysaccharide (LPS) evoked a dose- and time-dependent increase in TIMP-1 mRNA and a coincident down-regulation of the TIMP-3 gene. Astrocytes were found to express mRNA constitutively for MMPs -3, -11 and -14. In contrast, microglia expressed only MMP-12 mRNA under basal conditions. IL-1beta enhanced MMP-3 mRNA levels while LPS increased the MMP-3, -9, -12, -13 and -14 mRNAs. Our findings reveal that regulatory control of TIMP and MMP gene expression by glial cells is agonist- and cell-type specific, and suggest that innate immune signals govern the temporal and spatial expression patterns of TIMP and MMP genes in neuroinflammatory conditions of the CNS.
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PMID:Cell and agonist-specific regulation of genes for matrix metalloproteinases and their tissue inhibitors by primary glial cells. 1689 21

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