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)

Cardiotrophin-1 (CT-1) was cloned from mouse embryoid body for its ability to induce growth of heart cells. Predictions of its secondary structure indicate that CT-1 belongs to a family of cytokines with a four-helical bundle structure, and sequence comparisons reveal a weak homology to leukemia inhibitory factor (LIF) and ciliary neurotrophic factor (CNTF). Using a reverse transcriptase-polymerase chain reaction assay with rat sympathetic neuron cultures, we find that CT-1 induces and suppresses the expression of the same set of neuropeptide and neurotransmitter synthetic enzyme mRNAs as do LIF and CNTF. In addition, the effects of CT-1 and LIF are not additive, and CT-1 does not require a GPI-linked component to mediate its actions. Our functional data confirm that CT-1 is a member of the neuropoietic cytokine family and suggest that the CT-1 receptor complex contains the gp130 signal transducing component.
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PMID:Cardiotrophin-1 induces the same neuropeptides in sympathetic neurons as do neuropoietic cytokines. 937 58

To evaluate the role of the erythropoietin (Epo) receptor (R) in erythropoiesis in more primitive stem cells, we assessed the influence of retrovirus-mediated gene transfer of human (h) EpoR complementary DNA (cDNA) into murine embryonic stem (ES) cells on erythroid differentiation of these cells. The hEpoR cDNA was efficiently transduced into ES cells, forming hEpoR that stably expressed ES (ES-hEpoR) cells. Expression of hEpoR cDNA was confirmed in ES-hEpoR cells by reverse transcriptase-polymerase chain reaction and Northern blot analysis. Colony assays demonstrated that definitive erythroid and primitive erythroid colonies were significantly increased from ES-hEpoR cells, when compared with mock virus-transduced ES (ES-Neo) cells, during the time course of differentiation induced by withdrawal of leukemia inhibitory factor, in either the presence or the absence of Epo. Multipotential colony-forming units (CFU-Mix) were also increased in ES-hEpoR cells at different stages of differentiation, but no changes were detected for CFU-granulocyte-macrophage colonies (CFU-GM). Time course studies by Northern blot analysis demonstrated elevated levels of expression of beta-H1 and beta-Major globin genes in embryoid bodies derived from ES-hEpoR cells stimulated with Epo, when compared with similar expression from ES-Neo cells. Expression of the GATA-1 gene was enhanced in ES-hEpoR cells, when compared with ES-Neo cells, beginning immediately after initiation of the cultures until 8 days of differentiation. These data indicate that primitive and definitive erythropoiesis in differentiating embryoid bodies can be enhanced by retrovirus-mediated gene transfer of an hEpoR gene.
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PMID:Introduction of human erythropoietin receptor complementary DNA by retrovirus-mediated gene transfer into murine embryonic stem cells enhances erythropoiesis in developing embryoid bodies. 1091 75

Our previous study demonstrated that transduction of murine embryonic stem (ES) cells with a human erythropoietin (Epo) receptor (R) cDNA resulted in enhanced erythropoiesis in developing embryonic bodies (EBs). To address possible mechanisms of gene regulation, we compared gene expression between hEpoR cDNA-transduced ES (ES-hEpoR) cells and parental ES cells during in vitro differentiation induced by withdrawal of leukemia inhibitory factor (LIF) and cultured in the absence of Epo using differential display reverse transcriptase-polymerase chain reaction (DDRT-PCR). A total of 48 differentially expressed cDNA fragments were found; 12 were sequenced and five were confirmed by Northern blot analysis to be up- or down-regulated in ES-hEpoR cells during differentiation compared to parental ES cells. In a GenBank search of the five putatively regulated cDNA fragments, two fragments shared high sequence homology to two known genes: the Surf-6 gene and the gene for calcyclin binding protein. Northern blot analysis demonstrated that 2.5-kb and 0.3-kb transcripts of the Surf-6 gene were expressed in undifferentiated ES-hEpoR and parental ES cells at a low level, but this expression was enhanced from day 2 to 14 of differentiation after withdrawal of LIF and culture in the presence of Epo. Furthermore, the enhanced expression of these two transcripts was also noticed in EML-C1 cells, a murine multipotential hematopoietic cell line that has erythroid differentiation potential in response to Epo. In summary, our results demonstrate that Surf-6 gene expression is regulated during differentiation of hematopoietic stem/progenitor cells in response to Epo, suggesting a possible role for Surf-6 gene in erythropoiesis.
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PMID:Differentially expressed genes during in vitro differentiation of murine embryonic stem cells transduced with a human erythropoietin receptor cDNA. 1109 89

Removal of the synaptic targets of olfactory receptor neurons by olfactory bulb ablation results in apoptosis of olfactory receptor neurons and up-regulation of proliferation of their progenitors. This study focuses on the expression of the neuropoietic cytokines leukemia inhibitory factor (LIF) and its receptor (LIFR) and interleukin 6 (IL-6) and its receptor (IL-6R) in intercellular signaling pathways in the olfactory mucosa after target ablation. Olfactory bulbectomy (OBX) resulted in several transient, early-onset, temporally integrated events that were detected immunohistochemically. Macrophages infiltrated the olfactory epithelium (OE) by 16 hours post-OBX. LIF expression was up-regulated transiently at 2 days post-OBX, when up-regulated expression of LIFR also was detected on globose basal cells (GBCs), a subpopulation of which are immediate progenitors of olfactory receptor neurons. GBC proliferation peaked at 3--4 days post-OBX. In the olfactory nerve (ON), LIF-positive and IL-6-positive macrophage infiltration was followed by the transient up-regulation of expression of LIFR, IL-6, and IL-6R in ensheathing cells by 3 days post-OBX. The mRNAs for LIF/LIFR, IL-6/IL-6R, and their common signal-transduction molecule, gp130, in olfactory-nasal mucosa from control mice and from 3-day post-OBX mice were detected with reverse transcriptase-polymerase chain reaction (RT-PCR). Analysis of Northern blot and relative quantitative RT-PCR demonstrated similar temporal patterns of changes in relative mRNA levels for both LIF and IL-6, which were up-regulated by 16 hours post-OBX and peaked at 2--3 days post-OBX. These data indicate that LIF from infiltrating macrophages acts as a mitogen for GBCs and that LIF from infiltrating macrophages and IL-6 from infiltrating macrophages and ensheathing cells act as repair factors in the ON.
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PMID:Leukemia inhibitory factor, interleukin-6, and their receptors are expressed transiently in the olfactory mucosa after target ablation. 1137 11

Human disuse muscle atrophy frequently accompanies orthopedic injury, arthritis, or bed rest, and recovery is often incomplete despite current rehabilitation programs. We have studied the vastus lateralis muscle in 12 patients with chronic disuse atrophy associated with chronic osteoarthritis of the hip both preoperatively and after total hip arthroplasty. Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) demonstrated an increase in the level of expression of myostatin, insulin-like growth factor-1 (IGF-1) and leukemia inhibitory factor (LIF) mRNAs compared to healthy control muscle. In all patients there was a significant correlation preoperatively between increasing myostatin mRNA expression and reduction in type 2A and 2B fiber area. In the 8 female patients there was a significant correlation between increased myostatin mRNA expression and the atrophy factor calculated for 2A and 2B fiber types preoperatively. We hypothesize that a complex interaction occurs between muscle growth regulating factors in the genesis of muscle wasting. Our results indicate that myostatin is a muscle-wasting factor contributing to type 2B and 2A atrophy. Other muscle growth factors, such as IGF-1 and LIF, may be upregulated in a counterregulatory fashion or may be involved in the fiber type switching seen in disuse muscle wasting.
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PMID:Myostatin, insulin-like growth factor-1, and leukemia inhibitory factor mRNAs are upregulated in chronic human disuse muscle atrophy. 1141 Sep 16

Mast cell hyperplasia is observed in various inflammatory skin diseases. Although the mechanisms involved in the pathogenesis of these conditions remains largely uninvestigated, it is speculated that mediators produced in the lesional skin provide a favorable microenvironment for mast cell growth. Among the proinflammatory mediators, leukemia inhibitory factor (LIF), which shares a receptor component (gp130 subunit) with interleukin-6 (IL-6), has been identified as a mast cell growth-enhancing factor produced by cells of the keratinocyte-derived cell line (KCMH-1). In this study, we investigated the effect of four IL-6 family cytokines, IL-6, IL-11, oncostatin M (OSM) and LIF on mast cell growth in a mast cell/fibroblast co-culture system. When mouse bone marrow-derived cultured mast cells (BMMC) were maintained on a NIH/3T3 fibroblast monolayer, these cytokines induced proliferation of the mast cells, but none of the cytokines had any effect on mast cell proliferation in the absence of fibroblasts. mRNA for gp130 and receptors for the four IL-6 family cytokines were detected in NIH/3T3 fibroblasts by reverse transcriptase-mediated polymerase chain reaction. In contrast, only mRNA for the IL-11 receptor and gp130 were detected in BMMC. Tyrosine phosphorylation of gp130 was observed in NIH/3T3 fibroblasts after stimulation with all the cytokines. Some IL-6 family cytokines enhanced the production of stem cell factor (SCF), a potent mast cell growth factor, from NIH/3T3 fibroblasts, but the amount of SCF produced by NIH/3T3 fibroblasts was not paralleled by the mast cell growth-enhancement induced by the IL-6 family cytokines. When anti-SCF antibody was added with the IL-6 family cytokines in the BMMC/fibroblast coculture system, a significant effect of these cytokines remained, although the growth-enhancing activity was markedly reduced. A similar result was obtained when BMMC were prepared from W/W(V)-mice, which lack functional c-kit, in the BMMC/ fibroblast coculture system. These results suggest that IL-6 family cytokines stimulate mast cell growth by a fibroblast-dependent mechanism, and also suggest the existence of another pathway between BMMC and NIH/3T3 fibroblasts cooperating with the SCF/c-kit pathway. IL-6 family cytokines may thus contribute to mast cell hyperplasia in skin diseases.
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PMID:The IL-6 family cytokines, interleukin-6, interleukin-11, oncostatin M, and leukemia inhibitory factor, enhance mast cell growth through fibroblast-dependent pathway in mice. 1182 Jul 27

There is a growing recognition of choroid plexus functioning as a source of neuropeptides, cytokines and growth factors in cerebrospinal fluid (CSF) with diffusional access into brain parenchyma. In this study, choroid plexus and other components of the CSF circulatory system were investigated by Western blotting, reverse transcriptase polymerase chain reaction and immunohistochemistry for production of interleukin-6-related cytokines characterized by neuroactivity [cardiotrophin-1 (CT-1), ciliary neurotrophic factor, leukemia inhibitory factor, oncostatin M] and signaling through the gp130/leukemia inhibitory factor receptor-beta receptor heterodimer. Western blot analysis showed that CT-1 was the only cytokine family member detectable in adult rat choroid plexus, as in leptomeninges. The specificity of detection was verified with blots of the same tissues from CT-1-deficient mice. Levels of both CT-1 mRNA and protein were constitutively high in rat from birth through adulthood in choroid plexus, up-regulated postnatally in leptomeninges and undetectable in brain parenchyma. Using antigen retrieval, CT-1 immunolocalized to choroid epithelial cells in all choroid plexuses in addition to leptomeninges (arachnoid and pial-glial membranes). Ependymal cells lining the ventricular neuroaxis, unlike the central canal, were also CT-1-immunoreactive. Western blots indicated rat choroid epithelial cells express and release CT-1 immunoreactivity under defined culture conditions and also revealed the presence of a CT-1-like protein in human choroid plexus and CSF. Previously, CT-1 has been conceptualized to function as a target-derived factor for PNS neurons. Our study clearly demonstrates production of CT-1 in the postnatal and adult CNS, specifically by cell types comprising the blood-CSF barrier, and its accumulation in ventricular ependyma. This finding has broad implications for CT-1 functioning apart from other leukemia inhibitory factor receptor ligands as a CSF-borne signal of brain homeostasis, one possibly involving regulation of the barrier itself, the ependyma or target cells in the surrounding parenchyma, including the subventricular zone. A rationale for studies examining CT-1-deficient mice in these respects is provided by the data.
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PMID:Cardiotrophin-1 in choroid plexus and the cerebrospinal fluid circulatory system. 1521 67

Embryonic stem cell (ESC) culture is fragmented and laborious and involves operator decisions. Most protocols consist of 3 individual steps: maintenance, embryoid body (EB) formation, and differentiation. Integration will assist automation, ultimately aiding scale-up to clinically relevant numbers. These problems were addressed by encapsulating undifferentiated murine ESCs (mESCs) in 1.1% (w/v) low-viscosity alginic acid, 0.1% (v/v) porcine gelatin hydrogel beads (d = 2.3 mm). Six hundred beads containing 10,000 mESCs per bead were cultured in a 50-mL high-aspect-ratio vessel bioreactor. Bioreactor cultures were rotated at 17.5 revolutions per min, cultured in maintenance medium containing leukemia inhibitory factor for 3 days, replaced with EB formation medium for 5 days followed by osteogenic medium containing L-ascorbate-2-phosphate (50 microg/mL), beta-glycerophosphate (10 mM), and dexamethasone (1 microM) for an additional 21 days. After 29 days, 84 times as many cells per bead were observed and mineralized matrix was formed within the alginate beads. Osteogenesis was confirmed using von Kossa, Alizarin Red S staining, alkaline phosphatase activity, immunocytochemistry for osteocalcin, OB-cadherin, collagen type I, reverse transcriptase polymerase chain reaction, microcomputed tomography (micro-computed tomography) and Fourier transform infrared spectroscopic imaging. This simplified, integrated, and potentially scaleable methodology could enable the production of 3-demensional mineralized tissue from ESCs for potential clinical applications.
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PMID:Integrated 3-dimensional expansion and osteogenic differentiation of murine embryonic stem cells. 1798 91

This study was undertaken to establish rat embryonic stem (ES) cells from parthenogenetically developing blastocysts. Ten blastocysts were prepared by treatment of ovulated rat oocytes with ionomycin and cycloheximide, and three alkaline phosphatase-positive ES cell lines were established using the N2B27 medium supplemented with mitogen activated protein kinase kinase inhibitor PD0325901, glycogen synthase kinase 3 inhibitor CHIR99021, rat leukemia inhibitory factor, and forskolin. Expression of stem cell marker genes (Oct-4, rNanog, Fgf-4, and Rex-1) was confirmed in all three ES cell lines by reverse transcriptase-polymerase chain reaction (RT-PCR). Combined bisulfite restriction analysis showed that the differentially methylated region locus of five imprinted genes (H19, Meg3IG, Igf2r, Peg5, and Peg10) in these ES cells remained to be demethylated or was hypomethylated, which was similar to that in control ES cells established from normal blastocysts. Characteristics of the parthenogenetic blastocyst-derived ES cells were successfully transmitted to the next generation through a chimeric rat for one of the three ES cell lines. This is the first report on germline-competent (genuine) ES cells derived from parthenogenetically developing rat blastocysts.
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PMID:Derivation of embryonic stem cell lines from parthenogenetically developing rat blastocysts. 2401 May 70


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