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)

Alpha-1 antitrypsin messenger RNA (A1AT mRNA) was determined in alveolar macrophages and in peripheral blood monocytes of healthy individuals using a sensitive RNase protection assay. Determinations were made of bacterial lipopolysaccharide (LPS) stimulated and unstimulated cells. We found that the amount of A1AT mRNA increased 7.3 and 14 times after 4 h of incubation with LPS for monocytes and macrophages, respectively (relative to total RNA). The increase was 12.3 and 14.8 times, respectively, when expressed as increase per cell. In both cell types there was wide interindividual variation in LPS response: 2-36 and 5-12 times for monocytes and macrophages, respectively. The possible significance of A1AT production of monocytes and macrophages may be the local control of granulocytic proteases such as elastase and cathepsin G.
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PMID:Alpha-1 antitrypsin response of stimulated alveolar macrophages. 142 67

Human mononuclear phagocytes have the capacity to participate directly in extracellular matrix turnover via the secretion of neutral proteinases. These neutral proteinases include the serine proteinases, elastase and cathepsin G and the metalloproteinases, interstitial collagenase, 92 kD type IV collagenase, 72 kD type IV collagenase and stromelysin. Mononuclear phagocytes also produce the counter-regulatory metalloproteinase inhibitor, TIMP (tissue inhibitor of metalloproteinases). We have studied the capacity of normal human mononuclear phagocytes and of the human monocytic tumor line U937 to elaborate proteinases and inhibitors. The serine proteinases, elastase and cathepsin G, are present only at the earliest stages of mononuclear phagocyte differentiation (U937 cells in the basal state, freshly isolated peripheral blood monocytes) and are stored within intracellular granules. As human mononuclear phagocytes differentiate (U937 cells exposed to phorbol esters, human monocytes cultured in vitro), the cellular content of these serine proteinases declines rapidly. Accompanying the acquisition of a more differentiated state, the ability for regulated secretion of the neutral metalloproteinases is attained. This capacity is acquired in a sequential manner, with secretion of the 92 kD type IV collagenase observed at earlier states of differentiation while release of stromelysin requires a fully differentiated and LPS (lipopolysaccharide)-stimulated alveolar macrophage. Interstitial collagenase and 72 kD type IV collagenase are synthesized at intermediate stages of differentiation. In comparison to human fibroblasts, human mononuclear phagocytes produce approximately 10-30% of the interstitial collagenase, 10% of the stromelysin and 1-2% of the 72 kD type IV collagenase on a per cell basis. Synthesis of the 92 kD type IV collagenase is restricted to the inflammatory cell (but also occurs in neutrophils and keratinocytes).
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PMID:Neutral proteinase expression by human mononuclear phagocytes: a prominent role of cellular differentiation. 148 61

Human mononuclear phagocytes express an array of serine and metal dependent proteinases that are under complex developmental control and are also highly regulated by physiologic and pharmacologic stimuli. Monocytes contain the intracellular serine proteinases, elastase and cathepsin G, but have little metalloproteinase secretory capacity. Macrophages, on the other hand, produce predominantly metalloproteinases. Phorbol induced differentiation of promonocyte-like U937 cells into more mature mononuclear phagocytes results in transcriptional suppression of cathepsin G and temporally delayed onset of collagenase transcription. Mature macrophages upregulate metalloproteinase synthesis in response to lipopolysaccharide and phorbol myristic acetate; expression is downregulated with interferon gamma and dexamethasone. Thus, during the development of the mononuclear phagocyte, stores of serine proteinases are replaced by regulated secretion of metalloproteinases. These alterations may reflect changing roles of these cells in extracellular matrix degradation.
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PMID:Proteinases secreted by human mononuclear phagocytes. 190 75

Killing of Pseudomonas aeruginosa by a 55-kDa bactericidal protein (BP 55), a 30-kDa protein (BP 30), cathepsin G, elastase, and proteinase 3 has been compared. P. aeruginosa was resistant to killing by elastase and proteinase 3. BP 55 at a 50% lethal dose (LD50) of 0.23 micrograms of protein per 5 x 10(6) bacteria per ml killed P. aeruginosa and was far more active than BP 30 and cathepsin G. The LD50s of BP 30 and cathepsin G were 16.9 and 28.3 micrograms of protein per 5 x 10(6) bacteria per ml, respectively. Preincubation of BP 55 or BP 30 with lipopolysaccharide (LPS) from P. aeruginosa inhibited bactericidal activity. The N-terminal amino acid sequence of BP 55 and BP 30 revealed no relationship between the two proteins. However, a monoclonal antibody (AHN-15) reacted with both proteins by Western immunoblot. The bactericidal activity of cathepsin G toward P. aeruginosa appeared to be dependent on the availability of the active site of the enzyme; bactericidal activity was inhibited by phenylmethylsulfonyl fluoride (PMSF) and by the specific cathepsin G inhibitor, Z-Gly-Leu-Phe-CH2Cl. The enzyme and bactericidal activities of cathepsin G were also inhibited by LPS from P. aeruginosa. LPS from P. aeruginosa was shown to be a competitive inhibitor of the enzyme activity of cathepsin G. Elastase enzyme activity was also inhibited noncompetitively by LPS, but the enzyme was not bactericidal. We have concluded that all three bactericidal proteins (BP 55, BP 30, and cathepsin G) may bind to the LPS of the outer membrane of P. aeruginosa. It appears that the enzyme active site must be available for cathepsin G to kill P. aeruginosa and that the active site may be involved in the binding of cathepsin G to P. aeruginosa.
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PMID:Comparison of granule proteins from human polymorphonuclear leukocytes which are bactericidal toward Pseudomonas aeruginosa. 193 76

The J111 histiocytic cell line is capable of producing human alpha 1-antichymotrypsin (alpha 1 ACh) in culture. The protein is secreted rather than stored in the cell, has a similar size to plasma alpha 1 ACh (68 kDa) and can complex with human cathepsin G. Dexamethasone and culture supernatants from U937 monocyte-like cells and alveolar macrophages, but not bacterial lipopolysaccharide, stimulate alpha 1ACh secretion by J111 cells. The J111 cell line thus provides a useful tool for the study of factors controlling alpha 1ACh synthesis in vivo.
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PMID:Production of alpha 1-antichymotrypsin by the J111 cell line. 326 5

Serine proteinases of human polymorphonuclear neutrophils play an important role in neutrophil-mediated proteolytic events; however, the non-oxidative mechanisms by which the cells can degrade extracellular matrix in the presence of proteinase inhibitors have not been elucidated. Herein, we provide the first report that human neutrophils express persistently active cell surface-bound human leukocyte elastase and cathepsin G on their cell surface. Unstimulated neutrophils have minimal cell surface expression of these enzymes; however, phorbol ester induces a 30-fold increase. While exposure of neutrophils to chemoattractants (fMLP and C5a) stimulates modest (two- to threefold) increases in cell surface expression of serine proteinases, priming with concentrations of lipopolysaccharide as low as 100 fg/ml leads to striking (up to 10-fold) increase in chemoattractant-induced cell surface expression, even in the presence of serum proteins. LPS-primed and fMLP-stimulated neutrophils have approximately 100 ng of cell surface human leukocyte elastase activity per 10(6) cells. Cell surface-bound human leukocyte elastase is catalytically active, yet is remarkably resistant to inhibition by naturally occurring proteinase inhibitors. These data indicate that binding of serine proteinases to the cell surface focuses and preserves their catalytic activity, even in the presence of proteinase inhibitors. Upregulated expression of persistently active cell surface-bound serine proteinases on activated neutrophils provides a novel mechanism to facilitate their egress from the vasculature, penetration of tissue barriers, and recruitment into sites of inflammation. Dysregulation of the cell surface expression of these enzymes has the potential to cause tissue destruction during inflammation.
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PMID:Cell surface-bound elastase and cathepsin G on human neutrophils: a novel, non-oxidative mechanism by which neutrophils focus and preserve catalytic activity of serine proteinases. 759 96

The volatile sulphur compound methyl mercaptan (CH3SH) is a by-product of protein metabolism and a principal component of oral malodour. This investigation examines the effect of CH3SH on the enzymatic activities of cathepsins B and G and elastase, and on the production by human gingival fibroblasts of two key factors, prostaglandin E (PGE) and cAMP, of the PGE2-cAMP-dependent pathway, which may contribute to the increased production of collagenase and tissue destruction in human periodontal disease. The results demonstrate that CH3SH alone, or in combination with interleukin-1 (IL-1) or lipopolysaccharide, can significantly enhance the secretion of PGE2, cAMP and procollagenase by human gingival fibroblasts. CH3SH also stimulated mononuclear cells to produce IL-1, which can increase cAMP production, and act in synergism with the direct effect of CH3SH on cAMP. CH3SH also significantly enhanced the activity of cathepsin B, moderately suppressed that of cathepsin G, but did not significantly affect elastase. These results provide evidence that CH3SH could be a contributing factor in the enzymatic and immunological cascade of events leading to tissue degradation in periodontal diseases.
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PMID:Stimulation of enzyme and cytokine production by methyl mercaptan in human gingival fibroblast and monocyte cell cultures. 760 61

We examined the immunotherapeutic ability of activated B cells which bound to anti-CD3 monoclonal antibody (mAb) to enhance antitumor T cell immunity in vivo. A flow cytometric analysis revealed that LPS (lipopolysaccharide)-activated B cells (LPS blasts) expressed Fc receptor (FcR) which can bind to anti-CD3 mAb. LPS blasts were also stained with CTLA-4Ig, which can bind to costimulation molecules with high affinity, which suggested that LPS blasts expressed costimulation molecules on their surface. In an in vitro assay, T cells remarkably proliferated in the presence of LPS blasts and soluble anti-CD3 mAb, whereas this proliferation was blocked by the addition of CTLA-4Ig. In a model of metastasis established by the intravenous inoculation of melanoma cells, the in vivo administration of LPS blasts incubated with anti-CD3 mAb and followed by treatment with polyethylene glycol, to reinforce the binding, induced a low but significant antitumor activity against melanoma. The antitumor activity induced by the in vivo administration of LPS blasts which bound to anti-CD3 mAb was also detected in the spontaneously established model of metastasis. These results therefore suggest that the in vivo administration of activated B cells which bound to anti-CD3 mAb was able to enhance the antitumor T cell response against metastatic melanoma.
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PMID:The antitumor activity induced by the in vivo administration of activated B cells bound to anti-CD3 monoclonal antibody. 786 78

Vascular damage, initiated by host inflammatory cells, is a component of the pathophysiology of many acute and chronic inflammatory disorders. Neutrophil-mediated tissue damage is mediated primarily by proteinases, particularly elastase and cathepsin G. In this study we have identified endothelial binding of two key serine proteinase inhibitors (serpins), alpha 1-antitrypsin, the inhibitor of elastase, and alpha 1-antichymotrypsin, the inhibitor of cathepsin G. These serpins are shed from the endothelium into the supernatant when neutrophils adherent to the endothelium are activated. Endothelium activated by lipopolysaccharide (LPS) augments this process. Serpin-proteinase complexes activate neutrophils and induce further cytokine release, thereby amplifying inflammatory processes. Strategies aimed at preventing endothelial serpin depletion may help minimize vascular damage during inflammation.
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PMID:Endothelial serpins--protectors of the vasculature? 830 2

The influence of lipopolysaccharide (LPS) and various cytokines on the expression of the costimulatory molecule B7-1 and intercellular adhesion molecule-1 (ICAM-1), lymphocyte function associated antigen-3 (LFA-3) and human histocompatibility leucocyte antigen-DR (HLA-DR) on human monocytes and their effect on the costimulatory function was investigated. Freshly isolated human monocytes constitutively express ICAM-1, LFA-3 and HLA-DR, but no B7-1. B7-1 expression was up-regulated by LPS and, to a lesser extent, by interferon-gamma (IFN-gamma). The other stimuli tested, including IFN-alpha, granulocyte-macrophage colony-stimulating factor (GM-CSF), tumour necrosis factor-alpha (TNF-alpha) and GM-CSF+TNF-alpha, did not influence expression of B7-1 on monocytes. ICAM-1 and HLA-DR were up-regulated by IFN-gamma and LPS; LFA-3 expression was not influenced. LPS also effectively enhanced costimulatory function of monocytes as determined in the tetanustoxoid (TT) assay. Blocking of B7 by CTLA-4Ig inhibited the LPS-induced enhancement of costimulatory function almost completely. Our results indicate that the LPS-mediated up-regulation of the costimulatory function of human monocytes is mediated by B7. This mechanism may be important for host defence against Gram-negative bacteria.
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PMID:Lipopolysaccharide effectively up-regulates B7-1 (CD80) expression and costimulatory function of human monocytes. 855 95


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