Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Carboxylic esterases are widely distributed in hematopoietic cells. Monocytes express the esterase isoenzyme (termed 'monocyte-specific esterase', MSE) that can be inhibited by NaF in the alpha-naphthyl acetate cytochemical staining. We examined the expression of MSE in normal cells and primary and cultured leukemia-lymphoma cells. The MSE protein was demonstrated by isoelectric focusing (IEF); MSE mRNA expression was investigated by Northern blotting and reverse transcriptase-polymerase chain reaction (RT-PCR). The following samples were positive for MSE protein and Northern mRNA expression: 20/24 monocytic, 4/32 myeloid, and 1/20 erythroid-megakaryocytic leukemia cell lines, but none of the 112 lymphoid leukemia or lymphoma cell lines; of the normal purified cell populations only the monocytes were positive whereas, T, B cells, and granulocytes were negative; of primary acute (myelo) monocytic leukemia cells (CD14-positive, FAB M4/M5 morphology) 14/20 were Northern mRNA and 11/14 IEF protein positive. RT-PCR revealed MSE expression in 29/49 Northern-negative lymphoid leukemia-lymphoma cell lines. The RT-PCR signals in monocytic cell lines were on average 50-fold stronger than the mostly weak trace expression in lymphoid specimens. On treatment with various biomodulators, only all-trans retinoic acid significantly upregulated MSE message and protein levels but could not induce new MSE expression in several leukemia cell lines; lipopolysaccharide and interferon-gamma increased MSE expression in normal monocytes. Analysis of DNA methylation with sensitive restriction enzymes showed no apparent regulation of gene expression by differential methylation; the MSE gene is evolutionarily conserved among mammalian species; the half-life of the human MSE transcripts was about 5-6 h. The extent of MSE expression varied greatly among different monocytic leukemia samples. However, the MSE overexpression in a significant number of specimens was not associated with gene amplification, gross structural rearrangements or point mutations within the cDNA region. Taken together, the results suggest that MSE expression is not absolutely specific for, but strongly associated with cells of the monocytic lineage; MSE is either not expressed at all or expressed at much lower levels in cells from other lineages. The biological significance, if any, of rare MSE messages in lymphoid cells detectable only by the hypersensitive RT-PCR remains unclear. Further studies on the regulation of this gene and on the physiological function of the enzyme will no doubt be informative with respect to its striking overexpression in some malignant cells and to a possible role in the pathobiology of monocytic leukemias.
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PMID:Characterization of the monocyte-specific esterase (MSE) gene. 809 31

A cDNA encoding bovine interleukin 10 (IL10) was cloned and sequenced using total cellular RNA derived from concanavalin A (ConA)-stimulated peripheral blood mononuclear cells (PBMC). A cDNA was produced with reverse transcriptase using oligo(dT) primers, and was amplified using primers chosen from consensus regions of the mouse and human IL10 genes. The nucleotide sequence derived from this cDNA shares 84, 79 and 78% homology with the human, mouse and rat cDNAs, respectively. The deduced amino-acid sequence shares an overall 77, 71 and 74% homology with the human, mouse and rat IL10 proteins, respectively. Northern blot analysis of the bovine IL10 mRNA reveals expression of a single 1.8-kb transcript, reaching maximal levels between 8 and 24 h, in ConA-stimulated peripheral T-cells, and weak expression in lipopolysaccharide-activated macrophages.
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PMID:Characterization of a cDNA encoding bovine interleukin 10: kinetics of expression in bovine lymphocytes. 811 15

Constitutive expression of mRNAs for GRO alpha, GRO beta, GRO gamma, and MCP-1, belonging to the chemokine family of 8- to 10-kDa cytokines with chemotactic properties for granulocytes and monocytes, has been identified in freshly isolated human nasal and bronchial epithelium, and in bronchoalveolar macrophages (AM). Expression of GRO alpha, GRO gamma, and MCP-1, but not GRO beta, was found in airway epithelial cells. AM expressed all three GRO genes in addition to MCP-1. On reverse transcription, chemokine mRNAs yielded 0.5-30 cDNA molecules/cell, depending on the chemokine and cell type, as determined by a semiquantitative reverse transcriptase-polymerase chain reaction technique. When chemokine mRNA expression in AM and bronchial epithelium from healthy nonatopic individuals was compared, AM expressed more GRO alpha, but similar levels of GRO gamma, MCP-1, and interleukin-8 (IL-8), as in the bronchial epithelial cells. Modulation of chemokine expression by tumor necrosis factor-alpha (TNF-alpha; 10 ng/ml) or endotoxin [lipopolysaccharide (LPS), 100 ng/ml] exposure was studied in primary nasal epithelial cell and alveolar macrophage cultures. In epithelial cells, LPS did not induce chemokine expression but GRO alpha, IL-8, and MCP-1 were upregulated approximately 100-fold by TNF alpha; GRO gamma expression was elevated only 1.5- to 4-fold. In AM cultures, all three GROs were strongly induced by LPS with peak mRNA expression 24 h after stimulation (approximately 50- to 100-fold increase compared with control cultures). MCP-1 mRNA expression, on the other hand, was not increased by LPS in AM. GRO protein was present in supernatants of stimulated epithelial cells and AM.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Constitutive and stimulated MCP-1, GRO alpha, beta, and gamma expression in human airway epithelium and bronchoalveolar macrophages. 816 97

The murine cDNA, encoding the purine catabolic enzyme, ecto-5'-nucleotidase (NT), was cloned and the tissue-specific distribution of both the mRNA and enzyme activity was examined. Starting with kidney RNA and primers based on the known rat sequence, reverse transcriptase-polymerase chain reaction (RT-PCR) was utilized to obtain the complete sequence for the translated portion of the murine cDNA. Murine NT is 94% identical to human NT at the amino acid (aa) level and 86% identical at the nucleotide (nt) level. NT enzyme assays revealed greater than tenfold more NT activity in mature vs. immature murine T- and B-lymphocytes. A similar increase in NT activity was also found when the pre-B-cell line, 70Z/3, was induced to produce surface kappa light chains with lipopolysaccharide (LPS) and gamma-interferon (gamma-IFN). Thus, culture systems in which murine lymphocytes mature may be useful for examining the mechanisms of NT gene regulation, as well as the function of NT in the immune system. In tissues, enzyme activity varied over 30-fold, from the lowest levels in skeletal muscle, thymus and spleen to highest in placenta, kidney and forestomach. Levels of mRNA, as determined by RNase protection assay, showed increased NT expression in the early gestation site, as compared to non-pregnant uterus, and in day-19.5 placenta, as compared to day-13 chorioallantoic placenta. Messenger RNA levels were in general proportional to enzyme activity, except in the lung and glandular stomach where mRNA levels were higher than expected, based on enzyme activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Murine ecto-5'-nucleotidase (CD73): cDNA cloning and tissue distribution. 822 5

A number of recent studies suggest that cells of the immune system, e.g. peripheral blood mononuclear cells (PBMC), can synthesize and process POMC and secrete POMC-derived peptides, such as ACTH and endorphins, upon immune and hormonal challenges. From this, it has been proposed that POMC-derived peptides originating from lymphoid cells can function as hormones, for instance in a lymphoid-adrenal axis. In view of the important physiological implications of this proposal, the present study was designed to investigate the expression of the POMC gene in human PBMC and the production by these cells of alpha-, beta-, and gamma-endorphins (alpha E, beta E, and gamma E) peptides that are established end products of the posttranslational processing of POMC. PBMC of individual donors were used uncultured (fresh cells) or cultured for 24 and 48 h in the presence and absence of Concanavalin-A (Con-A), bacterial lipopolysaccharide, phytohemagglutinin, or CRH, and vasopressin, conditions that reportedly stimulate POMC activity in those cells, to investigate the presence of POMC transcripts by analysis of total RNA with Northern blotting and the reverse transcriptase polymerase chain reaction (RT-PCR). Large scale preparations containing over 10(9) cells (fresh, cultured with and without Con-A) originating from several donors were examined for the presence of POMC transcripts by analysis of poly(A)+ RNA on Northern blots and for the presence of alpha E, beta E, and gamma E by gel filtration over Sephadex G-75 and reverse phase HPLC, followed by assay of the fractions in four endorphin RIA systems with different specificities. On the Northern blots of total RNA, no POMC transcripts were detectable. In poly(A)+ RNA preparations, no full-length POMC mRNA was found, and it was estimated that the concentration of POMC mRNA, if present, was below approximately 0.005 transcript/cell in Con-A-stimulated cells and still lower in unstimulated cells. In accord with literature data, an 800- to 900-nucleotide POMC transcript was detected in cultured PBMC, and the levels of this transcript were stimulated by Con-A. In all samples analyzed with RT-PCR, a transcript spanning most of exons 2 and 3 was detectable only on Southern blots of the RT-PCR product, but not on agarose gels stained with ethidium bromide. Chromatographic analysis of endorphin immunoreactivities in cell extracts revealed no qualitative differences between the immunoreactive profiles of fresh PBMC or PBMC cultured with or without Con-A.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Analysis of proopiomelanocortin (POMC) messenger ribonucleic acid and POMC-derived peptides in human peripheral blood mononuclear cells: no evidence for a lymphocyte-derived POMC system. 840 37

Nitric oxide synthesis requires the cofactor tetrahydrobiopterin. We have examined the effect on nitric oxide synthesis in experimental endotoxic shock of 2,4- diamino-6-hydroxypyrimidine (DAHP), an inhibitor of GTP cyclohydrolase I, the first and rate limiting enzyme for tetrahydrobiopterin synthesis. Rats given lipopolysaccharide (LPS, 10 mg/kg) showed a large rise in plasma nitrate at 4 and 8 hours which was significantly reduced by DAHP (1 g/kg) given at the same time as LPS. There was a 40-50% reduction in the haem-NO signal detected in kidney by electron paramagnetic resonance spectroscopy. LPS produced hypotension at 3 hours and 6 hours and this was ameliorated at 6 hours in rats given DAHP. DAHP abolished the rise in kidney tetrahydrobiopterin levels seen 4 hours after LPS but no effect was seen on induction of inducible nitric oxide synthase (iNOS) as assessed by immunohistochemistry and reverse transcriptase PCR, consistent with the effect of DAPH being by reduction of tetrahydrobiopterin levels. The results show that inhibition of tetrahydrobiopterin synthesis is an effective strategy to reduce nitric oxide synthesis by iNOS in vivo.
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PMID:Inhibition of tetrahydrobiopterin synthesis reduces in vivo nitric oxide production in experimental endotoxic shock. 860 31

Fas ligand (FasL, Apo-1L) is a member of the tumor necrosis factor protein family and binding to its receptor (Fas, Apo-1, CD95) triggers cell death through apoptosis. Ligand expression is restricted to cells with known cytolytic activity and found on hematopoietic cells of the T cell and natural killer lineage. Here we provide evidence that B lymphocytes can express FasL. Flow cytometric analysis revealed that FasL is expressed on the surface of B cells upon stimulation with either lipopolysaccharide or phorbol 12-myristate 13-acetate/ionomycin. FasL expression on activated B cells was confirmed by western blot and reverse transcriptase polymerase chain reaction analysis. FasL on B cells is functional since lipopolysaccharide-activated B lymphocytes derived from wild type, but not from gld mutant mice, were able to kill Fas-sensitive target cells. Our data suggest that the Fas system may contribute to the control of B cell homeostasis.
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PMID:Activated B cells express functional Fas ligand. 860 44

Peptides with potent broad-spectrum antibiotic activity have been identified in many animal species. Recent investigations have demonstrated that epithelial cells are a site of antibiotic peptide expression, suggesting that these peptides contribute to host defense at mucosal surfaces. Expression of tracheal antimicrobial peptide (TAP), a member of the beta-defensin family of peptides, is inducible in cultured tracheal epithelial cells (TEC) upon challenge with bacterial lipopolysaccharide (LPS) (G. Diamond, J.P. Russell, and C.L. Bevins, Proc. Natl. Acad. Sci. USA, in press). In this study, an anchored reverse transcriptase PCR strategy was used to determine if TAP was the sole beta-defensin isoform expressed upon stimulation of the cells with LPS. In addition to TAP, a second class of cDNA clones which encoded lingual antimicrobial peptide (LAP), a beta-defensin peptide recently isolated from a different mucosal site, the bovine tongue, was identified (B.S. Schonwetter, E.D. Stolzenberg, and M. Zasloff, Science 267:1645-1648, 1995). Northern (RNA) blot analysis demonstrated in vivo expression of LAP mRNA in tracheal mucosa. Levels of LAP mRNA were higher in cultured TEC challenged with either LPS or tumor necrosis factor alpha than in control cells. Thus, a response of TEC exposed to inflammatory mediators is induction of antibiotic-encoding genes, including both TAP and LAP. This work complements the in vivo studies of Schonwetter et al. (cited above), which showed elevated levels of LAP mRNA in squamous epithelial cells of the tongue near sites of tissue injury and inflammation, by suggesting possible mediators of the in vivo observation. Together these lines of investigations support the hypothesis that inducible expression of endogenous antibiotic peptides by inflammatory mediators characterizes local defense of mammalian mucosal surfaces.
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PMID:Coordinate induction of two antibiotic genes in tracheal epithelial cells exposed to the inflammatory mediators lipopolysaccharide and tumor necrosis factor alpha. 861 61

This study shows that human ramified microglial cells derived from fetal brain primary cultures, are able to produce nitric oxide (NO). In fact, stimulation with Escherichia coli lipopolysaccharide (LPS) (1 microgram ml-1) or tumor necrosis factor alpha (TNF alpha) (500 U ml-1) enhances nitrite release in cell supernatants, as determined by the Griess reaction. A synergistic effect is achieved following treatment with LPS plus TNF alpha, this effect being inhibited by pretreating cells with NOS inhibitor N omega-nitro-L-arginine methyl ester (L-NAME). Using reverse transcriptase-polymerase chain reaction (RT-PCR) and Southern blot analysis, we also found that LPS/TNF alpha produce an increase of inducible NO synthase (iNOS) mRNA expression.
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PMID:Human ramified microglial cells produce nitric oxide upon Escherichia coli lipopolysaccharide and tumor necrosis factor alpha stimulation. 861 65

The increased levels of tumor necrosis factor-alpha (TNF-alpha) seen in patients with acquired immune deficiency syndrome (AIDS) may contribute to the AIDS-related wasting syndrome. TNF also induces expression of human immunodeficiency virus (HIV) through activation of the transcription factor NF-kappa B, which binds to the viral long terminal repeat (LTR). Because TNF can decrease the antiretroviral activity of zidovudine (AZT) in vitro, pentoxifylline (PTX) may increase the efficacy of AZT. PTX decreases HIV replication in acutely infected cells and inhibits gene expression controlled by the HIV-1 LTR. The antiretroviral activity of PTX is associated with decreased binding of NF-kappa B to its recognition sequences. Therefore, PTX may inhibit HIV expression indirectly by diminishing TNF production and directly, by decreasing activity of NF-kappa B. PTX, and an inhibitor of the viral transactivator TAT, Ro24-7429, may inhibit HIV gene expression in a cooperative fashion. The first clinical study of PTX in AIDS patients was conducted by us through the AIDS Clinical Trial Group of the National Institutes of Health. AIDS patients on antiretroviral therapy received PTX 400 or 800 mg three times daily for 8 weeks. TNF assays included TNF mRNA levels in peripheral blood mononuclear cells (PBMCs) and inducible TNF protein levels in the supernatant of PBMCs cultured in the presence of 0.1 microgram/ml lipopolysaccharide (LPS). The median change in TNF mRNA was a 30% decrease. There was a median and significant 40% decrease in the production of inducible TNF protein. HIV load decreased in 10 patients and increased in four patients, but did not change in the group as a whole. Others have extended our initial observations in HIV-infected patients. In a placebo-controlled trial, TNF production by unstimulated PBMCs decreased by 52% in the PTX arm and increased by 7.2% in the placebo arm. In a study comparing AZT, PTX, or a combination of the two, viral load after treatment was ninefold above baseline in the AZT or PTX alone arm, compared to only twofold in the combination arm. In a quality of life trial, PTX was associated with improvement in depression, anger, and social and cognitive function: a placebo effect, however, was not ruled out. PTX 400 mg three times daily is safe and well tolerated. PTX decreases PBMC TNF expression in HIV-infected patients, measured as protein in culture supernatant or as mRNA, and may decrease viral replication. Further studies of HIV-infected persons are needed to ascertain the benefit of PTX as an adjunct either to inhibitors of reverse transcriptase (e.g., AZT) or of transcription (e.g., TAT inhibitor).
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PMID:Pentoxifylline for the treatment of HIV infection and its complications. 869 54


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