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)

The mesothelium is a flat epithelial lining of serous cavities that could gate the traffic of molecules and cells between the circulation and these body compartments. The present study was designed to elucidate the capacity of mesothelial cells to express adhesion molecules and chemoattractant cytokines, two fundamental mechanisms of regulation of leukocyte recruitment. Cultured human mesothelial cells express appreciable levels of intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), and these were increased by in vitro exposure to tumor necrosis factor (TNF), interferon gamma (IFN-gamma), or TNF and IFN-gamma. Interleukin 1 (IL-1) was a less consistent stimulus for adhesion molecule expression in vitro. Unlike endothelial cells, used as a reference cell population, resting or stimulated mesothelial cells did not express E-selectin and ICAM-2, as assessed by flow cytometry. Analysis of VCAM-1 mRNA by reverse transcriptase and polymerase chain reaction using appropriate primers revealed that mesothelial cells expressed both the seven- and the six-Ig domain transcripts, with predominance of the longer species. Monocytes bound appreciably to "resting" and, to a greater extent, to stimulated mesothelial cells. Monocytes exposed to IFN-gamma and lipopolysaccharide, used as prototypic activation signals, showed increased capacity to bind mesothelial cells. Anti-CD18 monoclonal antibody significantly inhibited binding of monocytes to mesothelial cells, and this blocking effect was amplified by anti-very late antigen 4. Mesothelial cells were able to express the chemotactic cytokines IL-8 and monocyte chemotactic protein 1 at the mRNA and protein levels. These results indicate that mesothelial cells can express a set of adhesion molecules (ICAM-1 and VCAM-1) overlapping with, but distinct from, that expressed in vascular endothelium (ICAM-1, ICAM-2, VCAM-1, E-selectin), and that these are functionally relevant for interacting with mononuclear phagocytes. The regulated expression of adhesion molecules and chemotactic cytokines by mesothelial cells is probably important in inflammatory and immune reactions that involve serous cavities, such as the long-known macrophage appearance and disappearance reactions.
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PMID:Expression of adhesion molecules and chemotactic cytokines in cultured human mesothelial cells. 138 76

The present study was designed to explore the interaction of interleukin-13 (IL-13) with vascular endothelial cells (EC). In vitro exposure to IL-13 of human umbilical vein EC induced surface expression of vascular cell adhesion molecule-1 (VCAM-1). At optimal concentrations (10 to 50 ng/mL) and exposure times (24 hours), IL-13 was a twofold to threefold less effective inducer of VCAM-1 than IL-1, which was used as reference EC activator. When IL-13 was combined with IL-1, an almost additive induction of VCAM-1 was observed. Induction of VCAM-1 by IL-13 was selective in that E-selectin and intercellular adhesion molecule-1 (ICAM-1) were unaffected. IL-13 caused a modest reduction of IL-1 induction of E-selectin and ICAM-1. Surface expression of VCAM-1 on IL-13-treated cells was associated with mRNA induction (as assessed by Northern analysis and reverse transcriptase-polymerase chain reaction), with predominance of transcripts encoding the 7 Ig domain form of this molecule. In agreement with previous reports, IL-13 inhibited cytokine production in human monocytes. In contrast, IL-13 was a weak inducer and an amplifier (in concert with IL-1) of IL-6 expression in EC. Mesothelial cells, which share properties with EC and regulate the traffic and function of leukocytes in serosal cavities, were stimulated to express VCAM-1 and IL-6 by IL-13. Thus, IL-13 elicits a spectrum of responses in vascular endothelium remarkably similar to that of IL-4 and IL-10. Interaction of these cytokines with vascular endothelium may play an important role in the induction and expression of Th2-dependent responses.
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PMID:Regulation of endothelial and mesothelial cell function by interleukin-13: selective induction of vascular cell adhesion molecule-1 and amplification of interleukin-6 production. 752 94

The aim of this study was to investigate mechanisms of anti-tumour activity and necrosis induced by combinations of tumour necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma). In a breast cancer xenograft model, locally injected recombinant human TNF-alpha arrested growth of established tumours in the absence of overt necrosis. Macroscopic necrosis occurred when rat IFN-gamma, which had no anti-tumour activity as a single agent, was given systemically. Treatment with TNF-alpha and IFN-gamma caused focal engorgement of tumour capillaries with erythrocytes, intravascular recruitment of polymorphonuclear cells and platelet adherence to the tumour vascular endothelium 4 h after the combined treatment. This was followed by destruction of tumour vascular endothelium and both necrosis and apoptosis of tumour cells. Concomitant with these changes, semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed the increase of stromal (murine) mRNA levels for TNF-alpha, TNF receptor 55 kDa, TNF receptor 75 kDa, intracellular adhesion molecule 1, vascular cell adhesion molecule 1, P-selectin and interleukin 6 (IL-6). Thus, the effect of the combined TNF-alpha and IFN-gamma therapy involved the selective destruction of the tumour vasculature, death of tumour cells and increased expression of a series of stromal cytokines, cytokine receptors and adhesion molecules, which could be implicated in the observed events.
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PMID:Changes in endogenous cytokines, adhesion molecules and platelets during cytokine-induced tumour necrosis. 757 63

The purpose of the study was to obtain a comprehensive picture of the expression of cytochrome P450s (CYP) in the human lung, broncho-alveolar macrophages (BAM), and peripheral blood lymphocytes. The methods used were reverse transcriptase-polymerase chain reaction (RT-PCR) with gene-specific primers and immunohistochemistry with specific anti-peptide antibodies. In RT-PCR, CYPs 1A1, 2B6/7, 2E1, 2F1, 3A5 and 4B1 were detected in cDNA prepared from whole lung tissue. BAMs expressed CYPs 1B1, 2B6/7, 2C, 2E1, 2F1, 3A5 and 4B1. These tissues lacked CYPs 1A2, 2A6, 2D6, and 3A7. In peripheral blood lymphocytes, only CYP1B1 and CYP2E1 mRNAs were consistently detected. In immunohistochemistry with anti-CYP3A antibodies, epithelial staining of CYP3A5 was observed in 100% of individuals, while only about 20% exhibited CYP3A4 staining. CYP3A5 protein was localized in the bronchial wall, bronchial glands, bronchiolar epithelium, alveolar epithelium, vascular endothelium and alveolar macrophages. The results indicate that several different xenobiotic-metabolizing CYPs are present in the human lung, possibly contributing to in situ activation of pulmonary procarcinogens.
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PMID:Expression of xenobiotic-metabolizing cytochrome P450s in human pulmonary tissues. 944 17

Chemokines play an important role in the regulation of endothelial cell (EC) function, including proliferation, migration and differentiation during angiogenesis, and re-endothelialization after injury. In this study, reverse transcriptase-polymerase chain reaction was used to reveal expression of various CXC and CC chemokine receptors in human umbilical vein EC. Northern analysis showed that CXCR4 was selectively expressed in vascular EC, but not in smooth muscle cells. Compared with other chemokines, stromal cell-derived factor-1alpha (SDF-1alpha), the known CXCR4 ligand, was an efficacious chemoattractant for EC, causing the migration of approximately 40% input cells with an EC50 of 10-20 nM. Of the chemokines tested, only SDF-1alpha induced a rapid, though variable mobilization of intracellular Ca2+ in EC. Experiments with actinomycin D demonstrated that CXCR4 transcripts were short-lived, indicating a rapid mRNA turnover. Interferon-gamma (IFN-gamma) caused a pronounced down-regulation of CXCR4 mRNA in a concentration- and time-dependent manner. In a striking functional correlation, IFN-gamma treatment also attenuated the chemotactic response of EC to SDF-1alpha. IL-1beta, tumor necrosis factor-alpha, and lipopolysaccharide produced a time course-dependent biphasic effect on CXCR4 transcription. Expression of CXCR4 in EC is significant, more so as it and several CC chemokine receptors have been shown to serve as fusion co-receptors along with CD4 during human immunodeficiency virus infection. Taken together, these findings provide evidence of chemokine receptor expression in EC and offer an explanation for the action of chemokines like SDF-1alpha on the vascular endothelium.
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PMID:Chemokine receptors in human endothelial cells. Functional expression of CXCR4 and its transcriptional regulation by inflammatory cytokines. 946 27

Our aim was to investigate the collagenolytic potential and localization of matrix metalloproteinase-2 (MMP-2) in relation to its regulatory proteins membrane type MT1-MMP and tissue inhibitor of metalloproteinases-2 (TIMP-2) in rheumatoid arthritis (RA). For this purpose, we have used purification of MMP-2, MMP-8, MMP-9 and interstitial type I, II and III collagens; SDS-PAGE/densitometric collagenase activity assay; zymography; Western blotting; reverse transcriptase polymerase chain reaction; in situ hybridization; and immunofluorescence, ABC, ABC-APAAP double immunostainings. MMP-2 degraded human type II collagen almost as effectively as MMP-8, whereas MMP-9 did not cleave type II collagen. In synovial tissue, MT1-MMP, TIMP-2 and MMP-2 were found in synovial lining in fibroblast- and macrophage-like cells, in stromal cells and in vascular endothelium. MT1-MMP, TIMP-2 and MMP-2 were strongly expressed in the pannocytes of the invasive pannus at the interface, but staining was weak and/or there were few positive cells both "above" and "below" the soft-to-hard tissue (cartilage and/or bone) interface. Rheumatoid synovial tissue extract contained proteolytically active 62/59 kDa MMP-2 and 43 kDa MT1-MMP, but no free TIMP-2. These results indicate that components of the ternary MT1-MMP/TIMP-2/MMP-2 complex are coexpressed in the normal synovial lining and in its pathological extension on the hyaline articular cartilage. MMP-2 may participate in the remodeling of the normal lining and also seems to be localized/focalized to pannocytes at a site critical for tissue destruction in arthritis.
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PMID:New collagenolytic enzymes/cascade identified at the pannus-hard tissue junction in rheumatoid arthritis: destruction from above. 992 52

Vascular endothelial cells regulate vascular smooth muscle tone through Ca2+-dependent production and release of vasoactive molecules. Phospholamban (PLB) is a 24- to 27-kDa phosphoprotein that modulates activity of the sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA). Expression of PLB is reportedly limited to cardiac, slow-twitch skeletal and smooth muscle in which PLB is an important regulator of [Ca2+]i and contractility in these muscles. In the present study, we report the existence of PLB in the vascular endothelium, a nonmuscle tissue, and provide functional data on PLB regulation of vascular contractility through its actions in the endothelium. Endothelium-dependent relaxation to acetylcholine was attenuated in aorta of PLB-deficient (PLB-KO) mice compared with wild-type (WT) controls. This effect was not due to actions of nitric oxide on the smooth muscle, because sodium nitroprusside-mediated relaxation in either denuded or endothelium-intact aortas was unaffected by PLB ablation. Relative to denuded vessels, relaxation to forskolin was enhanced in WT endothelium-intact aortas. The endothelium-dependent component of this relaxation was attenuated in PLB-KO aortas. To investigate whether these changes were due to PLB, WT mouse aorta endothelial cells were isolated. Both reverse transcriptase-polymerase chain reaction and Western blot analyses revealed the presence of PLB in endothelial cells, which were shown to be >98% pure by diI-acetylated LDL uptake and nuclear counterstaining. These data indicate that PLB is present and modulates vascular function as a result of its actions in endothelial cells. The presence of PLB in endothelial cells opens new fields for investigation of Ca2+ regulatory pathways in nonmuscle cells and for modulation of endothelial-vascular interactions.
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PMID:Phospholamban is present in endothelial cells and modulates endothelium-dependent relaxation. Evidence from phospholamban gene-ablated mice. 1002 11

Tail blood flow (TBF) in the rat markedly increases during sympathetic withdrawal such as hyperthermia or lumbar sympathetic blockade. However, a long-term alteration of TBF after chronic sympathetic denervation is not well understood. In the present study, TBF following lumbar sympathectomy (LSX) was observed to ascertain whether subsequent changes in TBF occur in the absence of the sympathetic nervous activity in the rat tail. Assessed by recording tail and rectal temperature, the LSX immediately caused an increase in TBF. TBF was gradually decreased along with time and returned to the sham operated (SO) control level within 4 days. About a week after the surgery, a rapid increase in TBF in response to whole body heating was almost abolished in denervated animals. Neither hexamethonium (20 mg/kg, i.v.) for ganglion blockade nor intra-arterial infusion of alpha-receptor antagonist, phentolamine (10, 100 microg) produced vasodilation in LSX animals. Nitroprusside, a donor of nitric oxide, produced an increase in TBF in both LSX and SO animals. These results indicate that the tail vasculature after LSX constricts with capability to be vasodilated independent of sympathetic reinnervation. Quantification of the tail vascular mRNA expression by reverse transcriptase-polymerase chain reaction showed less endothelial nitric oxide synthetase in LSX group than that in SO group whereas endothelin-1 was not significantly different in both groups. It is suggested that functional changes in tail vascular endothelium takes at least a part in the reduction in TBF after LSX.
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PMID:The influence of chronic sympathectomy on cutaneous blood flow in the rat tail. 1045 3

Growing evidence suggests that beta-amyloid (Abeta) peptides play a central role in mediating vascular endothelium dysfunction, but the extent to which immune mechanisms are involved in this process remains unclear. To explore such mechanisms, we incubated cultured human aortic endothelial cells (HAEC) with freshly solublized Abeta and examined expression of a central immunoregulatory molecule, CD40, in these cells using reverse transcriptase-polymerase chain reaction, Western immunoblotting, and Flow cytometry. Our results show that treatment of endothelial cells with Abeta1-40, Abeta1-42 or gamma interferon (IFN-gamma) results in a dose-dependent induction of endothelial CD40 expression. Furthermore, ligation of endothelial CD40 and simultaneous treatment of human endothelial cells with IFN-gamma or Abeta peptides leads to a significant release of interleukin-1beta (IL-1beta), a marker for endothelial cell activation. Since IL-1beta is an important inflammatory response mediator, these findings suggest that the functional role of Abeta-induced endothelial CD40 may be promotion of the inflammatory cascade in vascular endothelial cells.
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PMID:Induction of CD40 on human endothelial cells by Alzheimer's beta-amyloid peptides. 1053 33

Membrane receptors for human chorionic gonadotropin (hCG) are expressed in a variety of steroidogenic cells, and also in extragonadal tissues such as vessels of the female genital tract. We examined the possible contribution of hCG to the endocrine control of prearteriolar mesenteric and uterine vessels before and during pregnancy. Lumen diameters of isolated pressurized resistance arteries from Sprague-Dawley rats were measured using a video-electronic system. hCG produced marked and dose-dependent vasodilation. Uterine radial arteries were found to be highly sensitive to hCG (EC50 approximately =60 mU/ml) before and throughout gestation. Second-order mesenteric arteries from nonpregnant animals were even more sensitive (EC50=38 mU/ml), but, in these vessels, responsiveness to hCG was significantly attenuated by the pregnant state. Mechanical removal of the vascular endothelium did not reduce the degree of vasodilation mediated by hCG. The expression of hCG receptor mRNA in intact vessels could be demonstrated using reverse transcriptase polymerase chain reaction (RT-PCR). hCG appears to be an important embryonic signal, which could trigger adaptive cardiovascular changes in early pregnancy, simultaneously preserving a sufficient utero-placental perfusion during the entire gestation period by an endothelium-independent mechanism.
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PMID:Human chorionic gonadotropin dilates uterine and mesenteric resistance arteries in pregnant and nonpregnant rats. 1065 Oct 16


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