Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cellular adherence is important for monocyte migration and function and is known to induce monocyte activation, leading to the production of mRNA for several proto-oncogenes and cytokines. In addition, since cellular adherence has important intracellular signalling function, it has the potential to enhance human immunodeficiency virus (HIV) replication in monocytic cells. We have investigated the effects of adhesion of the monocytic cell line THP-1 transfected with HIV1 or HIV2 long terminal repeat chloramphenicol acetyltransferase (LTR CAT) constructs. These studies have shown that adherence to tissue culture plastic or confluent endothelial cells is essential for enhanced HIV LTR CAT expression in lipopolysaccharide-stimulated cells. In addition, we have investigated the effects of engagement of specific adhesion molecules, using immobilized antibodies, on HIV replication in the promonocytic cell line OM101, which contains a single latent proviral copy of HIV. Such studies have demonstrated that engagement of CD18, the beta subunit of the lymphocyte function-related antigen-1 (LFA-1) and major histocompatibility complex class II (MHC II) enhanced HIV replication. LFA-1 is involved in both monocyte-endothelial cell interactions and monocyte-T-cell interactions, and MHC II is involved in monocyte interaction with antigen-specific T cells. These data suggest that such interactions of membrane adhesion molecules with their appropriate ligand enhance HIV replication in vivo. Thus, this study has demonstrated that cellular adherence is a key regulatory factor of HIV replication in monocytic cells.
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PMID:Cellular adherence enhances HIV replication in monocytic cells. 780 Sep 38

We and others have shown that some freshly isolated multiple myeloma (MM) cells and derived cell lines express interleukin 6 (IL-6) receptors and proliferate in vitro in response to IL-6; a subset of MM cells also expresses IL-6 mRNA, is intracytoplasmic IL-6 positive and secretes IL-6. We have shown that MM cells express the cell surface adhesion molecules CD29/CDw49d(VLA-4), CD18/CD11a(LFA-1) and CD44, and may localize to marrow via specific adherence to both extracellular matrix proteins and to bone marrow stromal cells (BMSCs). MM cell adhesion triggers IL-6 secretion by normal and MM BMSCs and related IL-6-mediated tumor cell growth. Our attempts to block MM cell adhesion to BMSC-induced IL-6 secretion by using antibodies to CD29/CDw49d, CD18/11a, and/or CD44 demonstrated minimal effects, suggesting that another ligand-receptor interaction triggers IL-6 secretion when MM cells and BMSCs are juxtaposed. Both MM cells and BMSCs express CD40. Triggering of MM cells and BMSCs via CD40 upregulates IL-6 secretion in both MM cells and MM-derived cell lines, as well as BMSCs and BMSC lines, suggesting the possibility of both autocrine and paracrine MM cell growth triggered via CD40. Finally, experiments using the LP 101 BMSC line transiently transfected with IL-6 promoter fragments linked to chloramphenicol acetyltransferase reporter gene demonstrate that adhesion of MM cells induces IL-6 gene transcription in BMSCs, which is conferred via the NF-kappa B binding motif.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regulation of interleukin 6 in multiple myeloma and bone marrow stromal cells. 852 May 9

The binding of beta2 (CD18) integrins on PMN cell membrane to intercellular adhesion molecule (ICAM) counter-receptors on the surface of vascular endothelial cells mediates PMN adhesion to endothelial cells. Neutrophil inhibitory factor (NIF), a 41-kD glycoprotein isolated from the canine hookworm (Ancylostoma caninum), is a beta2 integrin antagonist that inhibits PMN adhesion to endothelial cells. We transferred the NIF gene into CD1 mouse lungs by intravenous injection of cationic liposomes to study the effects of in vivo NIF expression on LPS-induced lung PMN sequestration and the development of lung injury. RT-PCR and Northern blot analysis indicated the lung-selective expression of the NIF transgene, and immunocytochemistry showed prominent NIF expression in pulmonary microvessel endothelial cells. NIF staining was also observed in intraluminal leukocytes present in pulmonary microvessels. This may be the result of NIF binding to leukocytes after its secretion from the transduced lung cells, since there was no evidence of NIF gene expression in circulating leukocytes. Pulmonary vascular NIF expression abrogated the lung tissue PMN uptake and airspace migration of PMN and prevented lung vascular injury (as measured by the lung tissue uptake of [125I]labeled albumin) after the intraperitoneal LPS challenge (200 microg/mouse). Expression of a control protein, chloramphenicol acetyltransferase (CAT), by the same strategy, had no effect on these responses. In vitro studies showed that NIF prevented mouse PMN adhesion consistent with the inhibition of lung uptake after LPS challenge in NIF transgene-expressing mice. We conclude that pulmonary vascular expression of NIF, a specific beta2 integrin- binding protein, is a potentially useful gene transfer strategy in modulating the infiltration of PMN across the alveolar-capillary epithelial barrier and in preventing lung vascular endothelial injury.
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PMID:In vivo expression of neutrophil inhibitory factor via gene transfer prevents lipopolysaccharide-induced lung neutrophil infiltration and injury by a beta2 integrin-dependent mechanism. 961 14

Adhesion to extracellular matrices is known to modulate leukocyte activation, although the mechanisms are not fully understood. Mononuclear phagocytes are exposed to fibrinous provisional matrix throughout migration into inflammatory foci, so this study was undertaken to determine whether fibrinogen triggers activation of NF-kappa B transcription factors. U937 cells differentiated with PMA in nonadherent culture were shown to express two fibrinogen-binding integrins, predominately CD11b/CD18, and to a lesser extent, CD11c/CD18. Cells stimulated with fibrinogen (10-100 microg/ml)/Mn2+ (50 microM) for 2 h were examined by electrophoretic mobility shift assay. NF-kappa B activation, minimal in unstimulated cells, was substantially up-regulated by fibrinogen. Fibrinogen also caused activation of AP-1, but not SP1 or cAMP response element-binding protein (CREB) factors. Blocking mAbs against CD18 and CD11b abrogated fibrinogen-induced NF-kappa B activation. To determine the effects on transcriptional regulation, U937 cells were transfected with a plasmid containing the HIV-1 enhancer (bearing two NF-kappa B sites) coupled to a chloramphenicol acetyltransferase (CAT) reporter. Cells were subsequently stimulated with 1) PMA for 24 h, inducing CAT activity by 2.6-fold, 2) fibrinogen/Mn2+ for 2 h, inducing CAT activity by 3.2-fold, or 3) costimulation with fibrinogen and PMA, inducing 5.7-fold the CAT activity induced by PMA alone. We conclude that contact with fibrinogen-derived proteins may contribute to mononuclear phagocyte activation by signaling through CD11b/CD18, resulting in selective activation of transcriptional regulatory factors, including NF-kappa B.
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PMID:Fibrinogen activates NF-kappa B transcription factors in mononuclear phagocytes. 968 12