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)

Airway mucosa consists of several types of cells including ciliated cells, mucus secreting cells, basal cells and Clara cells. In this review, fine structures of these epithelial cells and intercellular junctions are demonstrated by scanning and transmission electron microscopy, and the proposed kinetics of cellular maturation and development are discussed. Airway epithelium not only plays a role as a mechanical barrier at the air-surface interface but also possesses a wide variety of functions. Ciliary beating has been recognized to be one of the important determinants for mucociliary transport by clearing inhaled particles and bacteria from the airway. We found that the motility of cilia can be regulated by intracellular second messengers, such as Ca2+, cAMP, and protein kinase C. When ciliated epithelium is encountered by physicochemical stimuli, these signal transduction systems are activated through phosphatidylinositol turnover and/or Ca2+ channel opening, which subsequently modulate the synthesis of ATP, an energy source of ciliary beating. Airway epithelium contains the enzyme neutral endopeptidase which can degrade several peptides into inactive fragments, thus regulating the actions of tachykinins released from sensory C-fibers via axon reflex. Ion transport across airway mucosa is determined by Cl secretion and Na absorption in airway epithelium. To elucidate the mechanism of airway hypersecretion under several conditions of respiratory diseases, the effects of chemical mediators, neuropeptides, and inflammatory mediators on electrical properties of canine cultured tracheal epithelium were studied. We also expanded this idea to human subjects and found that indomethacin inhalation was valuable in reducing the amounts of sputum production by inhibiting Cl and water secretion into the airway lumen. In addition, airway epithelium can modulate contraction of airway smooth muscle by generating epithelium-derived relaxing factor (EpDRF). We have shown that lipopolysaccharide-induced airway hyperreactivity seems attributable to the loss of airway epithelium with EpDRF.
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PMID:[Structure and function of airway epithelial cells]. 207 99

Release of eicosanoids is an important response of macrophages to inflammation and bacterial infection. At low concentrations, bacterial lipopolysaccharide (1-2 micrograms/ml) fails to stimulate eicosanoid release in resident peritoneal macrophages but primes the macrophages for a greatly enhanced release of eicosanoids on stimulation with the calcium ionophore A23187 (0.1 microM) or with phorbol 12-myristate 13-acetate (50 nM), an activator of protein kinase C. Incubation of macrophages with Bordetella pertussis toxin, prior to priming with lipopolysaccharide, inhibited the release of both cyclooxygenase and lipoxygenase products upon A23187 stimulation. Pertussis toxin treatment of macrophages had no effect on eicosanoid release when the stimulus was phorbol 12-myristate 13-acetate. The presence of 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7), an effective inhibitor of protein kinase C, during lipopolysaccharide priming and subsequent stimulation significantly inhibited eicosanoid release when phorbol 12-myristate 13-acetate was the stimulus, but did not affect eicosanoid release stimulated by A23187. Based on these results, at least two mechanisms, distinguished by apparent differences in sensitivity to pertussis-toxin-sensitive, guanine-nucleotide-binding proteins and protein kinase C, are involved in eicosanoid secretion by lipopolysaccharide-activated macrophages in response to A23187 and phorbol 12-myristate 13-acetate.
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PMID:Pertussis toxin and H-7 distinguish mechanisms involved in eicosanoid release from lipopolysaccharide-primed macrophages. Eicosanoid release from lipopolysaccharide-primed macrophages. 210 89

To determine the potential regulatory mechanisms involved in synovial cell interleukin-1 (IL-1) release, the ability of gamma-interferon (gamma-IFN) to influence IL-1 release was assessed. Rat synovial cells cultured in the presence of a variety of stimuli, including lipopolysaccharide (LPS), failed to release IL-1. However, pretreatment of synovial cells with gamma-IFN, followed by LPS stimulation, resulted in increased levels of intracellular IL-1 as well as release of IL-1 from the cell. The level of IL-1 release was dependent on the concentration of both gamma-IFN and LPS, and on length of exposure to the gamma-IFN. The kinetic and dose requirements for gamma-IFN-dependent IL-1 release were similar to those for Ia antigen expression, but LPS was necessary for IL-1 messenger RNA induction, intracellular IL-1 accumulation, and IL-1 release. In addition, sequential treatment, i.e., gamma-IFN followed by LPS, was essential for IL-1 induction. Substitution of phorbol ester or calcium ionophore for gamma-IFN did not result in similar IL-1 release. In addition, induction of IL-1 messenger RNA by another stimulus was not sufficient to result in IL-1 release following LPS treatment. These results suggest that release of IL-1 by rat synovial cells requires the production of a regulatory signal, which is inducible by gamma-IFN.
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PMID:Interleukin-1 release by rat synovial cells is dependent on sequential treatment with gamma-interferon and lipopolysaccharide. 210 26

P815, a transformed mouse mastocytoma cell line, produced and released cytotoxic factors after stimulation with phorbol 12-myristate 13-acetate (PMA), but not with lipopolysaccharide (LPS), calcium ionophore A23187 and IgE receptor triggering. The cytotoxic activity was reduced 60% by antibodies to mouse tumour necrosis factor (TNF). In addition, we demonstrated that TNF mRNA was already expressed under normal culture conditions and that it increased after stimulation with PMA. Although it was unknown whether factors other than TNF were lymphotoxin or some other unknown factors, it has been suggested that mast cells have cytotoxic activity, and that they contribute to inflammatory response through the release of TNF, which has a wide range of biological activity.
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PMID:Production of tumour necrosis factor by mastocytoma P815 cells. 210 86

We describe here the involvement of calcium-activated neutral protease (CANP or calpain, EC 3.4.22.17) in calcium-dependent proteolytic processing of the precursor of human interleukin 1 alpha (IL-1 alpha) into mature IL-1 alpha. Calcium ionophore ionomycin enhanced proteolytic processing of pre-IL-1 alpha and the release of mature IL-1 alpha either from lipopolysaccharide (LPS)-activated human adherent mononuclear cells or from a human bladder carcinoma cell line (HTB9 5637) that constitutively produces human IL-1 alpha and -beta. The proteolytic processing of pre-IL-1 alpha was completely inhibited by EGTA. Similar calcium-dependent proteolytic processing of pre-IL-1 alpha was also observed with lysates of either LPS-activated human adherent mononuclear cells or HTB9 5637 cells. Since the optimal pH for processing was between 7 and 8, and E-64 (a cysteine protease inhibitor) and leupeptin (a serine and cysteine protease inhibitor) both inhibited this processing by cell lysates, we hypothesized that a calcium-activated neutral protease, CANP, might be responsible for this processing. This hypothesis was supported by data showing that the specific CANP inhibitor peptide inhibited this proteolysis in cell lysates in a dose-dependent fashion (IC50 = 0.05 microM) and that treatment of pre-IL-1 alpha with purified CANP yielded the 17-kDa mature form of IL-1 alpha, which has an amino terminus identical with that reported for mature human IL-1 alpha. Taken together, these findings indicate that calcium-dependent proteolytic processing of pre-IL-1 alpha is selectively mediated by CANP.
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PMID:Identification of calcium-activated neutral protease as a processing enzyme of human interleukin 1 alpha. 211 74

Cells that produce interleukin-6 (IL-6) require the presence of signaling molecules since this cytokine is not normally constitutively expressed. It is now established that astrocytes produce IL-6; however, the precise inducing molecules and the kinetics of their action have not yet been clearly identified. In the current study, we show that either interleukin-1 beta (IL-1 beta) or tumor necrosis factor-alpha (TNF-alpha) exert a strong inducing signal for IL-6 in primary rat astrocytes. When the two cytokines are added together the response is synergistic, suggesting that each cytokine may induce IL-6 gene expression by different pathways. Interferon-gamma (IFN-gamma) does not affect IL-6 expression although if it is added in conjunction with IL-1 beta, an augmented induction of IL-6 occurs. In addition to the cytokines, bacterial lipopolysaccharide (LPS) and the calcium ionophore, A23187, induce IL-6 expression. IL-6 expression can be blocked by the glucocorticoid analogue, dexamethasone. IL-6 induction by LPS/Ca2+ ionophore is more sensitive to the suppressive effects of dexamethasone than is IL-6 induction by TNF-alpha/IL-1 beta. Cycloheximide (CHX), an inhibitor of protein synthesis, markedly increased levels of IL-6 mRNA in both unstimulated and stimulated astrocytes, indicating that ongoing protein synthesis is not required for astrocyte IL-6 gene expression. We propose that astrocyte-produced IL-6 may have a role in augmenting intracerebral immune responses in neurological diseases such as multiple sclerosis (MS), AIDS dementia complex (ADC), and viral infections. These diseases are characterized by infiltration of lymphoid and mononuclear cells into the central nervous system (CNS), and intrathecal production of immunoglobulins. IL-6 may act to promote terminal differentiation of B cells in the CNS, leading to immunoglobulin synthesis.
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PMID:Induction and regulation of interleukin-6 gene expression in rat astrocytes. 212

Our previous studies indicate that bacterial lipopolysaccharide (LPS) enhances natural killer (NK) cell-mediated cytotoxicity and increases intracellular calcium (Ca2+) in hepatocytes. Calmodulin (CAM) regulates Ca2(+)-ATPase activity, intracellular Ca2+, and is also implicated in NK cell-mediated cytolysis. In the present work, the effects of LPS and CAM on Ca2(+)-ATPase and intracellular Ca2+ in human NK cells were studied by a combined technique of immunogold electron microscopy and ultracytochemistry. Peripheral blood mononuclear cells were treated with 100 micrograms/ml E. coli (0111:B4) LPS and/or 5 micrograms/ml CAM in RPMI 1640 medium at 37 degrees C for 1 or 4 hr. NK cells labeled with monoclonal anti-Leu-11a (CD16) antibody and colloidal gold-conjugated anti-mouse IgG were processed for cytochemical localization of Ca2(+)-ATPase and Ca2+. Ca2(+)-ATPase was localized in the plasma membrane of NK cells, and its activity was suppressed by LPS but was enhanced by CAM. However, no apparent changes in the enzyme reaction were observed when cells were exposed to CAM concomitantly with LPS or stimulated with LPS before CAM. Apparent reduction of the enzyme reaction was observed when LPS stimulation was preceded by CAM. Ca2(+)-ATPase reaction in mitochondria was observed only in NK cells exposed to CAM. Computer image analysis showed no changes in the intracellular Ca2+ in NK cells treated with LPS for 1 hr, whereas a significant increase in Ca2+ was found in cells exposed to LPS for 4 hr. The intracellular Ca2+ significantly decreased in NK cells treated with CAM or with a combination of LPS and CAM as compared to that of controls (p less than 0.05). The results indicate that CAM is capable of blocking or reversing the inhibitory effect of LPS on Ca2(+)-ATPase, and suggest that in human NK cells the plasma membrane-associated Ca2(+)-ATPase is responsible for extrusion of intracellular Ca2+.
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PMID:Effects of bacterial lipopolysaccharide and calmodulin on Ca2(+)-ATPase and calcium in human natural killer cells, studied by a combined technique of immunoelectron microscopy and ultracytochemistry. 213 83

This study evaluated the gene expression of tumour necrosis factor (TNF) and the molecular weight of the cytotoxic factor in a subline of a rat basophilic leukaemia cell line, RBL-2H3. After IgE receptor triggering with a specific antigen that was associated with histamine release, cytotoxic activity in the cell lysates and supernatants increased for 2 hr during the culture of RBL-2H3 cells. Furthermore, calcium ionophore A23187 could induce release of histamine and cytotoxic activity from RBL-2H3 cells. However, compound 48/80, lipopolysaccharide (LPS) and phorbol 12-myristate 13-acetate (PMA) were unable to induce the release of either histamine or cytotoxic activity from the cells. These data suggested that, at least in part, there was a common pathway in histamine release and production of cytotoxic activity. A protein synthesis inhibitor, cycloheximide, did not affect histamine release, but inhibited the induction of cytotoxic activity. This cytotoxic activity from RBL-2H3 cells was completely neutralized by anti-mouse TNF rabbit serum. With Northern blot analysis, mouse TNF cDNA probe could hybridize with RNA isolated from RBL-2H3 cells. TNF mRNA was induced as early as 1 hr after stimulation with specific antigen and decreased by 4 hr. Moreover, the molecular weight (MW) of the released cytotoxic factor from RBL-2H3 cells triggered with IgE receptors was approximately 17,000 by SDS-PAGE, which was compatible to that of TNF. Thus, it is concluded that the gene expression and production of TNF occurred in RBL-2H3 cells after IgE receptor triggering in association with histamine release, suggesting that TNF produced by basophils and mast cells may play an important role in allergic reaction through its wide range of biological activity.
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PMID:Gene expression and production of tumour necrosis factor by a rat basophilic leukaemia cell line (RBL-2H3) with IgE receptor triggering. 214 21

Bacterial lipopolysaccharide (LPS) enhanced expression of C3bi receptors (CR3), phagocytosis of opsonized bacteria, and subsequent hydrogen peroxide (H2O2) production by human polymorphonuclear leukocytes (PMNs). The role of changes in intracellular calcium concentration ([Ca2+]i) in LPS-induced priming was examined by determining the effect of modulators of intracellular calcium on enhanced PMN function, determining the ability of calcium ionophores to reproduce the effects of LPS, and measuring PMN [Ca2+]i following addition of LPS. Inhibition of intracellular calcium-dependent processes with TMB-8 or quin-2 blocked all three measures of LPS-induced priming. LPS did not stimulate an increase in [Ca2+]i, and calcium ionophores failed to reproduce the effect of LPS. Maintenance of [Ca2+]i is necessary for LPS priming, but an increase in [Ca2+]i is not a component of the signal transduction pathway leading to PMN priming by LPS.
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PMID:Bacterial lipopolysaccharide enhances polymorphonuclear leukocyte function independent of changes in intracellular calcium. 214 24

The expression of tumor necrosis factor-alpha (TNF-alpha) mRNA in murine inflammatory peritoneal macrophages (M phi) was studied with a sensitive liquid hybridization method. Upon exposure to 10-1000 ng/ml of lipopolysaccharide (LPS), M phi were induced to express TNF-alpha mRNA in a dose-dependent manner. mRNA was detectable within 1 h after stimulation, peaked at about 2 h and then gradually declined. A 10 min treatment with LPS was enough to stimulate the maximal level of TNF-alpha mRNA, as determined in a 2 h period. Although calcium ionophore A23187 and macrophage activating factor (MAF) (both can activate M phi to mediate tumoricidal activity) did not induce TNF-alpha mRNA expression by themselves, they did act synergistically with LPS. Treatment of M phi with retinoic acid strongly inhibited LPS-induced TNF-alpha mRNA expression, whereas trifluoperazine had an opposite effect. Cycloheximide not only synergized with LPS but also induced TNF-alpha mRNA expression by itself. In contrast, actinomycin D completely blocked LPS-induced TNF-alpha gene activation. These findings indicate that LPS-induced TNF-alpha mRNA expression is not solely due to an increase in intracellular free calcium ion and is independent of the protein kinase C pathway of signal transduction. In addition, TNF gene activity may be regulated by short-lived protein repressor(s).
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PMID:[Regulation of tumor necrosis factor-alpha mRNA expression in murine peritoneal macrophages]. 215 Mar 51


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