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: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Following traumatic injury to the spinal cord, hematogenous inflammatory cells including neutrophils, monocytes, and lymphocytes infiltrate the lesion in a distinct temporal sequence. To examine potential mechanisms for their recruitment, we measured chemokine mRNAs in the contused rat spinal cord, using specific and sensitive reverse transcriptase polymerase chain reaction (RT-PCR) dot-blot hybridization assays. The neutrophil chemoattractant GRO-alpha was 30-fold higher than control values at 6 hr postinjury and decayed rapidly thereafter. LIX, a highly related alpha-chemokine, also was elevated early postinjury. Monocyte chemoattractant peptide (MCP)-1 and MCP-5 mRNAs, potent chemoattractants for monocytes, were significantly elevated at the lesion epicenter at 12 and 24 hr postinjury and declined thereafter. Interferon-gamma-inducible protein, 10 kDa (IP-10), chemoattractant towards activated T-lymphocytes, was significantly elevated at 6 and 12 hr postinjury. The dendritic cell chemoattractant MIP-3alpha also was increased, perhaps contributing to the development of T-cell autoreactivity to neural components after spinal cord injury (SCI) in rats. Other beta-chemokines, including MIP-1alpha and RANTES (regulated on expression normal T-cell expressed and secreted), were minimally affected by SCI. Expression of chemokines, therefore, directly precedes the influx of target neutrophils, monocytes, and T-cells into the spinal cord postinjury, as noted previously. Thus, selective chemokine expression may be integral to inflammatory processes within the injured spinal cord as a mechanism of recruitment for circulating leukocytes.
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PMID:Selective chemokine mRNA accumulation in the rat spinal cord after contusion injury. 969 65

The major target organ of systemic infection with the intracellular bacterium Listeria monocytogenes is the liver, to where inflammatory leukocytes are rapidly recruited. We determined by reverse transcriptase polymerase chain reaction the early chemokine response in the liver after systemic infection of mice with listeriae, and in parallel compared chemokine release from macrophages and hepatocytic cells in vitro. Murine bone marrow-derived macrophages (BMM) grown in fetal calf serum-supplemented medium were used as macrophages and the TIB75 cell line as hepatocytic cells. Within 1-3 hours, gene expression of monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1 alpha, MIP-2, KC, and interferon-gamma inducible protein-10 (IP-10) was upregulated in liver tissue of infected mice. BMM infected in vitro with L. monocytogenes showed a generalized chemokine response, and readily released MCP-1, MIP-1 alpha, MIP-2, and KC, as measured by enzyme-linked immunosorbent assay. In contrast, the chemokine response of hepatocytic cells was more restricted, and infection induced MCP-1 and KC, but not MIP-2 and MIP-1 alpha. Interferon gamma enhanced chemokine release from hepatocytic cells, but unexpectedly had either no or a negative effect on chemokine secretion by BMM cultured in serum-supplemented medium. Listeriolysin (Hly)-negative avirulent listeriae as well as listeriae killed by heat or gentamycin initiated a similar chemokine response in BMM and hepatocytic cells as did wild-type L. monocytogenes. Stimulation of hepatocytic cells with the monokines, tumor necrosis factor alpha and interleukin (IL-)1 alpha, but not IL-6, augmented liberation of chemokines. Together, our data demonstrate an early hepatic chemokine response to L. monocytogenes in murine listeriosis. Probably, not only macrophages but also parenchymal cells participate in chemokine production.
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PMID:Macrophages and hepatocytic cells as chemokine producers in murine listeriosis. 971 70

1. Intraperitoneal (i.p.) injection of murine recombinant IL-1beta (mrIL-1beta) produced a dose-dependent (0.5-50 ng) and time-related (0.5-2 h) secretion of murine monocyte chemoattractant protein-1 (mMCP-1; 3-4 ng per cavity) in the lavage fluids. MCP-1 mRNA could also be detected in the cell pellets by reverse transcriptase-polymerase chain reaction (RT-PCR). 2. MCP-1 levels were reduced by more than 90% by co-administration of IL-1 receptor antagonist (10 microg) (n=6, P<0.05). In contrast, an IL-1 mutant with low affinity for IL-1 receptor type I, termed yIL-1betadelta4 (50 ng), produced only a modest release of the chemokine. Treatment of mice with dexamethasone (DEX) (approximately 1 mg kg(-1) s.c.) reduced mrIL-1beta-induced mMCP-1 gene expression (apparent total inhibition) and protein release in the lavage fluids (approximately 40% reduction; n=10; P<0.05). Drastic reductions in the numbers of residential macrophages or mast cells did not modify the levels of mMCP-1 recovered in the lavage fluids. 3. Injection of mrIL-1beta produced neutrophil accumulation into the peritoneal cavities (maximal at 4 h with 1.42+/-0.15 x 10(6) cells per mouse). Co-injection of a specific polyclonal antibody against mMCP-1 reduced this process by more than 50% (n=6; P<0.05). In conclusion, we studied the mechanisms leading to the specific release of the CC chemokine mMCP-1 after in vivo administration of mrIL-1beta.
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PMID:Investigation of the functional role played by the chemokine monocyte chemoattractant protein-1 in interleukin-1-induced murine peritonitis. 978 4

To isolate the interferon-inducible protein 10 (IP-10) receptor gene, we searched for cells that respond to IP-10. Among several human and murine T cell lines, only CTLL2 cells ( a murine cytotoxic T cell line) responded to IP-10 with transient elevation of intracellular Ca2+. The murine IP-10 receptor gene has been cloned from cDNA derived from CTLL2 cells using the reverse transcriptase-polymerase chain reaction protocol with two degenerate primers corresponding to conserved regions of chemokine receptors. The cDNA encoding the murine IP-10 receptor has an open reading frame of 1101 bp corresponding to a protein of 367 amino acids that exhibits 86 % identity with the human IP-10 receptor. It mediates Ca2+ mobilization in response to IP-10, but does not recognize other rodent chemokines, including GRO, RANTES, monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein-1alpha (MIP-1alpha). Northern blot analysis revealed that murine IP-10 and its receptor mRNA were constitutively expressed in the spleen and thymus from normal mouse, while IP-10 and its receptor mRNA were derived from stromal cells and lymphocytes in both tissues, respectively. In vivo treatment with concanavalin A (Con A) for 12 hrs revealed that splenocytes significantly induce IP-10 receptor mRNA expression and show a good chemotactic response to IP-10. Therefore, it is supposed that IP-10 and its receptor are important for lymphocyte trafficking to lymphoid organs and that the IP-10 receptor on lymphocytes is rapidly inducible on inflammation or in immunological events.
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PMID:Cloning of the murine interferon-inducible protein 10 (IP-10) receptor and its specific expression in lymphoid organs. 979 Sep 4

Certain types of chemokine receptors have been identified as coreceptors for HIV-1 infection. The process of viral entry is initiated by the interaction between an envelope protein gp120 of HIV-1, CD4, and one of the relevant coreceptors. To understand the precise mechanism of the Env-mediated fusion and entry of HIV-1, we examined whether the V3 region of gp120 of T-cell line tropic (T-tropic) virus directly interacts with the coreceptor, CXCR-4, by using five synthetic V3 peptides: two cyclized V3 peptides (V3-BH10 and V3-ELI) which correspond to the V3 regions of the T-tropic HIV-1 IIIB and HIV-1 ELI strains, respectively, a linear V3 peptide (CTR36) corresponding to that of HIV-1 IIIB strain; and cyclized V3 peptides corresponding to that of the macrophage-tropic (M-tropic) HIV-1 ADA strain (V3-ADA) or the dualtropic HIV-1 89.6 strain (V3-89. 6). FACScan analysis with a CXCR-4(+) human B-cell line, JY, showed that V3-BH10, V3-ELI, and V3-89.6 but not CTR36 or V3-ADA blocked the binding of IVR7, an anti-CXCR-4 monoclonal antibody (MAb), to CXCR-4 with different magnitudes in a dose-dependent manner, while none of the V3 peptides influenced binding of an anti-CD19 MAb at all. Next, the effects of the V3 peptides on SDF-1beta-induced transient increases in intracellular Ca2+ were investigated. Three V3 peptides (V3-BH10, V3-ELI, and V3-89.6) prevented Ca2+ mobilization. Furthermore, the three peptides inhibited infection by T-tropic HIV-1 in a dose-dependent manner as revealed by an MTT assay and a reverse transcriptase assay, while the other peptides had no effects. These results present direct evidence that the V3 loop of gp120 of T-tropic HIV-1 can interact with its coreceptor CXCR-4 independently of the V1/V2 regions of gp120 or cellular CD4.
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PMID:T-tropic human immunodeficiency virus type 1 (HIV-1)-derived V3 loop peptides directly bind to CXCR-4 and inhibit T-tropic HIV-1 infection. 981 11

Indoor air pollutants may cause inflammatory changes of the airways and adjacent pulmonary tissue. After phagocytosis of inhaled particles alveolar macrophages (AM) release chemotactic mediators capable of attracting inflammatory cells into the lung tissue. To evaluate these mechanisms further peripheral blood mononuclear cells (PBMNC) and human AM (freshly recovered from the lower respiratory tract) were exposed to the indoor particles Soot FR 101 and Printex 90, the asbestos fiber Chrysotile B, and titanium dioxide (TiO2) at concentrations of 10 or 50 microg/10(6) cells for up to 8 h. The migration of granulocytes into the conditioned supernatants of AM and PBMNC was quantified by chemotaxis assay in a Boyden chamber. Granulocyte migration increased by 42.3 +/- 25.8% (Chrysotile B), 64. 6 +/- 18.3% (FR 101), 74.2 +/- 16.5% (P 90), and 86.7 +/- 25.6% (TiO2) in AM-conditioned supernatants (p < 0.05). Qualitative, Interleukin (IL)-8 specific reverse transcriptase-polymerase chain reaction was performed after exposure of AM or PBMNC to Chrysotile B, FR 101, P 90, and TiO2 at concentrations of 10 and 50 microg/10(6) cells for 90 min. Each of the tested particles caused an increase in IL-8-specific mRNA expression of AM or PBMNC after particle exposure compared with the unexposed control. To find out if IL-8, the most powerful granulocyte chemokine, is involved, supernatants were preincubated with anti-IL-8. Granulocyte migration decreased by up to 35 +/- 15% (50 ng/ml anti-IL-8) and 41.5 +/- 16% (100 ng/ml anti-IL-8) (p < 0.0625) in AM-conditioned supernatants. Pretreatment of the granulocytes with human IL-8 decreased by up to 59 +/- 18% (10 ng/ml) (p < 0.0625) in AM-conditioned supernatants. Similar reaction patterns were observed using anti-IL-8-pretreated supernatants of particle-exposed PBMNC. In conclusion, indoor air pollutants may promote inflammatory changes in the lung via IL-8 release by alveolar macrophages.
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PMID:Indoor air pollutants stimulate interleukin-8-specific mRNA expression and protein secretion of alveolar macrophages. 983 30

Human herpesvirus-8 (HHV-8) has been described in association with two lymphoproliferative disorders: one benign, multicentric Castleman's disease (MCD), and one malignant, primary effusion lymphoma (PEL). The factors that lead to malignant transformation of lymphoid cells are unknown, although most cases of PEL also are positive for EBV, suggesting a role for EBV as a cofactor in malignant transformation. We encountered a rare case of an HHV-8-associated MCD, followed by the development of an HHV-8-positive pleural PEL and a gastric large cell lymphoma in an HIV-seronegative male patient. The lesions were negative for Epstein-Barr virus (EBV). The combination of these diverse HHV-8-associated lymphoproliferative disorders in a single patient afforded us the ability to study potential differences in gene expression in these conditions. HHV-8 DNA was demonstrated by PCR in lymphoid tissues involved by MCD and PEL. By reverse transcriptase-PCR, HHV-8-related transcripts, including vG-coupled protein receptor, vbcl2, vcyclin D, vIL-6, vMIPI, and vMIPII, were detected in the PEL from the pleural cavity and the gastric lymphoma, whereas these transcripts, except for vIL-6, were not detected in a lymph node biopsy with MCD. Expression of hIL-10 was weak in the PEL from the pleural cavity, and expression of hIL-6 was undetectable in all three lesions. These data suggest that vIL-6 may be integral to the pathogenesis of MCD, whereas other viral transcripts that encode oncogene and chemokine homologues are important for HHV-8 tumorigenicity.
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PMID:Expression of human herpesvirus-8 oncogene and cytokine homologues in an HIV-seronegative patient with multicentric Castleman's disease and primary effusion lymphoma. 988 64

Local immune responses are thought to play an important role in the development of atherosclerosis. Histological studies have shown that human atherosclerotic lesions contain T lymphocytes throughout all stages of development, many of which are in an activated state. A number of novel CC chemokines have been described recently, which are potent chemoattractants for lymphocytes: PARC (pulmonary and activation-regulated chemokine), ELC (EBI1-ligand chemokine), LARC (liver and activation-regulated chemokine), and SLC (secondary lymphoid-tissue chemokine). Using reverse transcriptase-polymerase chain reaction and in situ hybridization, we have found gene expression for PARC and ELC but not for LARC or SLC in human atherosclerotic plaques. Immunohistochemical staining of serial plaque sections with specific cell markers revealed highly different expression patterns of PARC and ELC. PARC mRNA was restricted to CD68+ macrophages (n = 14 of 18), whereas ELC mRNA was widely expressed by macrophages and intimal smooth muscle cells (SMC) in nearly all of the lesions examined (n = 12 of 14). ELC mRNA was also found to be expressed in the medial SMC wall of highly calcified plaques (n = 4). Very low levels of ELC mRNA expression could also be detected in normal mammary arteries but no mRNA expression for PARC was detected in these vessels (n = 4). In vitro, ELC mRNA was found to be up-regulated in aortic SMC stimulated with tumor necrosis factor-a and interferon-gamma but not in SMC stimulated with serum. Both PARC and ELC mRNA were expressed by monocyte-derived macrophages but not monocytes. The expression patterns of PARC and ELC mRNA in human atherosclerotic lesions suggest a potential role for these two recently described CC chemokines in attracting T lymphocytes into atherosclerotic lesions.
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PMID:Expression and cellular localization of the CC chemokines PARC and ELC in human atherosclerotic plaques. 1002 95

Lymphoepithelioma-like carcinoma (LELC) of the lung is a recently recognized primary non-small cell lung carcinoma with distinct clinicopathological features and an aetiological association with Epstein-Barr virus (EBV) infection. The tumour consists of clusters and sheets of poorly or undifferentiated tumour cells in close association with numerous mononuclear inflammatory cells, including a rich component of tumour-associated macrophages (TAMs). To investigate the molecular mechanism leading to the TAM-rich stroma, the expression of a monocyte-specific chemotactic and activating factor, monocyte chemoattractant protein-1 (MCP-1), was studied by reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization (ISH), and the presence of TAMs was demonstrated by immunohistochemistry in nine LELCs. The results were compared with those found in 17 conventional non-small cell lung carcinomas. RT-PCR showed specific MCP-1 amplification in both LELCs and non-LELCs, but ISH demonstrated a unique and extensive expression of MCP-1 transcripts by the tumour cells of LELCs only, while TAMs, stromal fibroblasts, and endothelial cells formed the major source of MCP-1 in non-LELCs. TAMs in LELCs were more abundant and showed a close topographical relationship with the MCP-1-expressing tumour cells. The results indicate that tumour cell expression of MCP-1 in LELCs is an important mechanism contributing to their distinctive morphological features. This is the first study that demonstrates the in vivo upregulation of a monocyte-specific chemokine by EBV-related carcinomas, illustrating an interesting aspect of tumour biology in EBV-related neoplasms.
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PMID:Monocyte chemoattractant protein-1 (MCP-1) expression in primary lymphoepithelioma-like carcinomas (LELCs) of the lung. 1020 85

Alveolar macrophages (AM) are important host-defense cells and targets of human immunodeficiency virus type 1 (HIV-1) infection. However, the receptors mediating HIV-1 entry into AM are not completely characterized. We observed that, in addition to CD4 receptors, AM from healthy adults expressed low levels of CCR5, CCR3, and CXCR4 chemokine receptors by flow cytometry, and specific messenger RNA was detected for all three receptors by reverse transcriptase/polymerase chain reaction. The macrophage monocytotropic (M-tropic; YU2) and dual-tropic (89.6) HIV-1 env-pseudotypes entered AM efficiently, as expected given CCR3 and CCR5 expression. However, the T-lymphocytotropic (T-tropic; HXB2) pseudotype did not enter AM despite expression of the appropriate chemokine coreceptor CXCR4. Incubation of AM with regulated on activation, normal T cells expressed and secreted (RANTES) significantly impaired entry of the M-tropic (YU2) HIV-1 pseudotype, whereas SDF-1beta or eotaxin did not impair entry. The entry of simian immunodeficiency virus (SIV) pbj1.9 env-pseudotype into AM was not blocked by RANTES, SDF-1beta, or eotaxin. The competence of these chemokine receptors for virus entry was confirmed in Cf2Th canine thymocytes cotransfected with the human CD4 and chemokine receptors. Entry of the M-tropic (YU2) HIV-1 pseudotype was shown to be mediated by either CCR3 or CCR5, the T-tropic (HXB2) HIV-1 pseudotype by CXCR4, and the dual-tropic (89.6) HIV-1 or the SIVpbj1. 9 pseudotype by CCR5, CCR3, or CXCR4. Our data indicate that the mechanisms for HIV-1 entry are both receptor-specific and cell type-specific, and that chemokine receptor expression on AM does not fully explain cell susceptibility to different virus isolates.
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PMID:CD4 receptor-dependent entry of human immunodeficiency virus type-1 env-pseudotypes into CCR5-, CCR3-, and CXCR4-expressing human alveolar macrophages is preferentially mediated by the CCR5 coreceptor. 1022 56


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