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)

Human angiogenin is a 14-kDa secreted protein with angiogenic and ribonucleolytic activities. Angiogenin is associated with tumour development but is also present in normal biological fluids and tissues. To further address the physiological role of angiogenin, we studied its expression in situ and in vitro, using the human term placenta as a model of physiological angiogenesis. Angiogenin was immunodetected by light and transmission electron microscopy, and its cellular distribution was established by double immunolabelling with cell markers including von Willebrand factor, platelet/endothelial cell adhesion molecule-1 (PECAM-1), CD34, Tie-2, vascular endothelial cadherin (VE-cadherin), vascular endothelial growth factor receptor-2 (VEGF-R2), erythropoeitin receptor (Epo-R), alpha-smooth muscle actin, CD45, cytokeratin 7, and Ki-67. Angiogenin immunoreactivity was detected in villous and extravillous trophoblasts, the trophoblast basement membrane, the endothelial basal lamina, foetal blood vessels, foetal and maternal red blood cells, and amnionic cells. Its expression was confirmed by in situ hybridisation with a digoxygenin-labelled cDNA probe and reverse transcriptase-polymerase chain reaction amplification. Villous cytotrophoblasts, isolated and differentiated in vitro into a functional syncytiotrophoblast, expressed and secreted angiogenin. Given its known biological activities in vitro and its observed pattern of expression, these data suggest that, in human placenta, angiogenin has a role not only in angiogenesis but also in vascular and tissue homeostasis, maternal immune tolerance of the foetus, and host defences.
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PMID:Angiogenin distribution in human term placenta, and expression by cultured trophoblastic cells. 1516 1

Human umbilical cord blood (UCB) has been regarded as an alternative source for cell transplantation and cell therapy because of its hematopoietic and nonhematopoietic (mesenchymal) potential. Although there has been debate about whether mesenchymal stem cells (MSCs) are invariably present in UCB, several reports showed that MSC-like cells could be consistently derived from human UCB and, moreover, could differentiate into various cells of a mesodermal origin. However, it remains unclear whether these UCB-derived MSCs are also capable of differentiating into skeletal muscle cells. In this study, we isolated MSCs from human UCB and induced them to differentiate into skeletal muscle cells. During cell culture expansion, UCB-derived mononuclear cells gave rise to adherent layers of fibroblast-like cells expressing MSC-related antigens such as SH2, SH3, alpha-smooth muscle actin, CD13, CD29, and CD49e. More important, when these UCB-derived MSCs were incubated in promyogenic conditions for up to 6 weeks, they expressed myogenic markers in accordance with myogenic differentiation pattern. Both flow cytometric and reverse transcriptase-polymerase reaction analyses showed that two early myogenic markers, MyoD and myogenin, were expressed after 3 days of incubation but not after 2 weeks. At week 6, more than half of UCB-derived MSCs expressed myosin heavy chain, a late myogenic marker. Our results demonstrate that UCB-derived MSCs possess a potential of skeletal myogenic differentiation and also imply that these cells could be a suitable source for skeletal muscle repair and a useful tool of muscle-related tissue engineering.
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PMID:Skeletal myogenic differentiation of mesenchymal stem cells isolated from human umbilical cord blood. 1527 7

At present the involvement of cardiac valve interstitial cells (VICs) in growth, repair, and tissue engineering is understudied. Therefore, this study aims at characterizing ovine VICs in order to provide a solid base for tissue engineering of heart valves. Ovine ICs of the four heart valves were isolated by the explant outgrowth method and expanded in vitro up to passage 5. Vimentin and collagen I gene expression from freshly isolated or cultured ICs was measured by reverse transcriptase-polymerase chain reaction. Immunocytochemical stainings of vimentin, alpha-smooth muscle actin (ASMA), smooth muscle myosin, and procollagen I were performed on aortic VICs. In addition, migration and extracellular matrix deposition were studied in vitro in aortic VICs. ICs show stable vimentin and collagen I expression in culture. Expression is approximately doubled in cultured ICs compared with fresh isolates. More than 95% of ICs in each passage stain for vimentin and procollagen I. Freshly isolated ICs are ASMA and myosin negative, but ICs in culture partially stain for these contractile markers. ICs have stable matrix production for up to five passages, associated with stable migration of the cells. We conclude that ovine valve interstitial cells undergo phenotypic modulation to activated myofibroblasts under culture conditions but retain stable matrix production.
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PMID:Molecular and functional characterization of ovine cardiac valve-derived interstitial cells in primary isolates and cultures. 1558 97

Human fetal cord blood contains subsets of mononuclear cells with the potential to form both hematological and endothelial cells. Vascular progenitor cells, which can produce all three elements of mature blood vessels, including smooth muscle, have been identified in animals. We hypothesized that similar multipotential progenitor cells exist in humans and used the expression of alpha-smooth muscle actin (alpha-SMA) to identify such cells in fetal cord blood. Mononuclear cell preparations were isolated from human umbilical cord blood and CD34(+) and CD133(+) cells obtained by magnetic bead separation. Isolated cells were cultured on fibronectin-coated dishes with medium containing vascular endothelial growth factor, basic fibroblast growth factor, and insulin-like growth factor. mRNA was extracted, and the expression of alpha-SMA and a number of endothelial cell markers (VEGFR-2, vWF, eNOS, VE-Cadhein, PECAM-1 and Tie-2) was determined by reverse transcriptase-PCR techniques. Human umbilical vein endothelial cells (HUVECs) were used as positive controls. Freshly isolated CD34(+) and CD133(+) cells expressed all endothelial cell markers, but did not express alpha-SMA. HUVECs expressed alpha-SMA. Following 4 weeks of culture, CD34(+) isolates produced morphologically endothelial-like cells that expressed both endothelial cell markers and alpha-SMA. CD133(+) cells failed to produce morphological endothelial-like cells but expressed a range of endothelial markers. However, they did not express alpha-SMA. Following culture in an endothelial cell-promoting environment, CD34(+), but not CD133(+), isolates produced endothelial-like cells that expressed alpha-SMA. Human fetal cord blood contains a population of cells that may differentiate toward both an endothelial and a smooth muscle phenotype in culture.
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PMID:Smooth muscle alpha-actin expression in endothelial cells derived from CD34+ human cord blood cells. 1558 9

Although leptin is a key adipokine promoting liver fibrosis, adiponectin may prevent liver injury. To determine the role of these adipokines in liver fibrosis and to understand their expression in vivo, fa/fa rats and their lean littermates were subjected to bile duct ligation (BDL). Histomorphometry for collagen and alpha-smooth muscle actin (alpha-SMA) revealed that lean rats, but not fa/fa littermates, had significant fibrosis with abundant hepatic stellate cell (HSC) activation. The lean-BDL rats had significantly higher leptin concentrations in the hepatic vein than lean sham-operated, fa/fa BDL, or fa/fa sham-operated rats. Co-localization of leptin and alpha-SMA in activated HSCs was observed by immunohistochemistry. Real-time reverse transcriptase-polymerase chain reaction and Western blot analysis confirmed the presence of leptin and alpha-SMA in activated, but not quiescent, HSCs, whereas only quiescent HSCs synthesized adiponectin mRNA and protein. Adiponectin overexpression in activated HSCs reduced proliferation, augmented apoptosis, and reduced expression of alpha-SMA and proliferating cell nuclear antigen. Adiponectin receptors (AdipoR1 and AdipoR2) were detected in both activated and quiescent HSCs, but only activated HSCs produced significant apoptosis after treatment with either globular or full-length adiponectin. Adiponectin may act to reverse HSC activation, maintain HSC quiescence, or significantly, may have important therapeutic implications in liver fibrosis.
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PMID:The roles of leptin and adiponectin: a novel paradigm in adipocytokine regulation of liver fibrosis and stellate cell biology. 1592 Jan 51

Immunohistochemical analysis using paraffin-embedded specimens is the method of choice to evaluate protein expression at a cellular level while preserving tissue architecture in normal and neoplastic tissues. Current knowledge of the expression of terminal differentiation markers in the mouse mammary gland relies on the evaluation of frozen tissues by use of immunofluorescence. We assessed changes in patterns of expression of terminal differentiation markers throughout the development of the mouse mammary gland in paraffin-embedded tissues. The expression of alpha-smooth muscle actin (SMA) and keratins (K) 5, 8/18, and 14 was influenced by the development stage of the mammary gland. Expression of K5 and SMA was restricted to basal cells. Keratin 14 was consistently expressed by mammary basal cells, and was detected in scattered luminal cells from 13.5 days after conception through puberty. Labeling for K8/18 of luminal cells was heterogeneous at all times. Heterogeneous expression patterns in luminal cells suggest this layer has cells with a variety of biological functions. The absence of K6 expression at any stage of the development of the mammary gland was confirmed by use of reverse transcriptase-polymerase chain reaction analysis, which indicates that this intermediate filament is not a marker of the mammary gland stem cell. Finally, consistent with results of earlier studies, keratins 1, 10, 13, and 15, and filaggrin, involucrin, and loricrin were not detected at any stage of mammary gland development.
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PMID:Expression of terminal differentiation proteins defines stages of mouse mammary gland development. 1640 85

The authors have previously reported the derivation of colonic subepithelial myofibroblasts (SEMFs) in both humans and mice from bone marrow (BM). In the pathogenesis of inflammatory bowel disease (IBD), such as Crohn's disease and ulcerative colitis, colonic SEMFs mediate several types of inflammatory response. In the present study, interleukin (IL)-10-/- mice were used as a model of IBD to investigate the involvement of BM-derived cells in the inflamed mucosa. Male whole BM [either C57/BL10 (wild type: WT) or IL-10-/- donor mice] was used to perform bone marrow transplantation (BMT) into both WT and IL-10-/- female mice. Tissue samples were evaluated by immunohistochemistry for alpha-smooth muscle actin expression and by in situ hybridization using a Y-chromosome-specific probe to track the donor-derived colonic SEMFs. The mucosal expression of mRNA for pro-inflammatory cytokines was analysed by reverse transcriptase-polymerase chain reaction (RT-PCR). In addition, mRNA expression of matrix metalloproteinase (MMP)-7 and osteopontin in the inflamed mucosa was assessed using in situ hybridization. Body weights and histological scores showed that IL-10-/- mice that received WT BM had an improved course of colitis, decreased mucosal pro-inflammatory mRNA expression, and up to 30% of their SEMFs were of BM origin. Conversely, IL-10-/- mice receiving IL-10-/- BM progressed to extensive colitis, and Y probe analysis revealed that up to 45% of colonic SEMFs were of BM origin. WT mice receiving IL-10-/- or WT BM had no signs of colonic inflammation. The expression of MMP-7 and osteopontin was up-regulated in the inflamed mucosa. In conclusion, IL-10-/- mice displayed ameliorated disease activity after WT BMT, whilst colitis was not induced in WT mice by IL-10-/- BMT. The contribution of BM-derived cells to colonic SEMFs was significantly increased in the inflamed mucosa compared with non-inflamed mucosa.
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PMID:Bone marrow transplantation ameliorates pathology in interleukin-10 knockout colitic mice. 1655 Jun 33

This study investigated the effect of thalidomide on oxidative stress in rat liver cirrhosis. The cirrhosis of rat was induced by intraperitoneal injection of carbon tetrachloride thrice weekly; meanwhile, thalidomide (10mg/kg or 100mg/kg) was given daily by intragastric administration for 8 weeks. The content of oxidative stress parameters, including superoxide dismutase, glutathione peroxidase, and malondialdehyde, in the liver was detected by biochemical assay. Immunohistochemistry revealed alpha-smooth muscle actin (alpha-SMA), desmin, and tissue inhibitor of metalloproteinase-1 (TIMP-1) protein in the liver. Nuclear factor kappa B p65 (NF-kappaBp65) protein in nucleus and transforming growth factor beta1 (TGF-beta1) protein in cytoplasm were detected by Western blot. NF-kappaBp65, TGF-beta1, and TIMP-1 mRNA levels in the liver were studied using reverse transcriptase polymerase chain reaction. Liver histopathology was significantly improved in rats given high doses of thalidomide. The content of oxidative stress parameters and the expressions of NF-kappaBp65, TGF-beta1 and TIMP-1 protein, and mRNA were significantly decreased in these animals. The expressions of alpha-SMA and Desmin protein were also significantly decreased in them. Thalidomide might exert an effect on the inhibition of oxidative stress via downregulation of NF-kappaB signaling pathway to prevent the progression of liver cirrhosis.
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PMID:Thalidomide prevents rat liver cirrhosis via inhibition of oxidative stress. 1703 Apr 52

Our objective was to establish the role of fibroblasts in medial vascular calcification, a pathological process known to be associated with elastin degradation and remodeling. Rat dermal fibroblasts were treated in vitro with elastin degradation products and transforming growth factor (TGF)-beta1, factors usually present in deteriorated matrix environments. Cellular changes were monitored at the gene and protein level by reverse transcriptase-polymerase chain reaction, enzyme-linked immunosorbent assay, immunofluorescence, and von Kossa staining for calcium deposits. By 21 days, multicellular calcified nodules were formed in the presence of elastin degradation products and TGF-beta1 separately and to a significantly greater extent when used together. Before mineralization, cells expressed alpha-smooth muscle actin and large amounts of collagen type I and matrix metalloproteinase-2, characteristic features of myofibroblasts, key elements in tissue remodeling and repair. Stimulated cells expressed increased levels of core-binding factor alpha1, osteocalcin, alkaline phosphatase, and osteoprotegerin, representative bone-regulating proteins. For most proteins analyzed, TGF-beta1 synergistically amplified responses of fibroblasts to elastin degradation products. In conclusion, elastin degradation products and TGF-beta1 promote myofibroblastic and osteogenic differentiation in fibroblasts. These results support the idea that elastin-related calcification involves dynamic remodeling events and suggest the possibility of a defective tissue repair process.
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PMID:Osteogenic responses in fibroblasts activated by elastin degradation products and transforming growth factor-beta1: role of myofibroblasts in vascular calcification. 1759 59

Ezrin is a cytoskeleton linker protein that is actively involved in the metastatic process of cancer cells. We have searched for a prognostic value of ezrin and some of its partners: alpha-smooth muscle actin and CD44H in 37 patients with an osteosarcoma. Automate immunohistochemistry (IHC) with anti-ezrin, alpha-smooth muscle actin and CD44H antibodies was performed in 66 specimens: 37 biopsies before chemotherapy, 16 resected tumours of "poor" responders and 13 metastases. The messenger RNA (mRNA) levels of ezrin of 13 frozen biopsies and 4 metastases were evaluated by real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR). All results were correlated to the following clinical data. Ezrin expression by IHC was found in 62% of 37 biopsies in the different histological subtypes. A good correlation was found between positive or negative samples by IHC and mRNA levels. Ezrin expression was recorded in 84.5% of metastastic samples. The mean expression of ezrin was higher in metastases than biopsies (p = 0.024). In multivariate analysis, ezrin was an independent prognostic marker for event-free survival and overall survival (OS) with p < 0.001 and p = 0.003, respectively, and alpha-smooth muscle actin for OS only (p = 0.024). Our findings suggest that ezrin and alpha-smooth muscle actin are predictive IHC prognostic markers for patients with an osteosarcoma.
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PMID:Ezrin and alpha-smooth muscle actin are immunohistochemical prognostic markers in conventional osteosarcomas. 1778 74


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