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:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Steel factor (SF) and LIF (leukemia inhibitory factor) synergistically promote the proliferation and survival of mouse primordial germ cells (PGCs), but only for a limited time period in culture. We show here that addition of bFGF to cultures in the presence of membrane-associated SF and LIF enhances the growth of PGCs and allows their continued proliferation beyond the time when they normally stop dividing in vivo. They form colonies of densely packed, alkaline phosphatase-positive, SSEA-1-positive cells resembling undifferentiated embryonic stem (ES) cells in morphology. These cultures can be maintained on feeder layers for at least 20 passages, and under appropriate conditions give rise to embryoid bodies and to multiple differentiated cell phenotypes in monolayer culture and in tumors in nude mice. PGC-derived ES cells can also contribute to chimeras when injected into host blastocysts. The long-term culture of PGCs and their reprogramming to pluripotential ES cells has important implications for germ cell biology and the induction of teratocarcinomas.
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PMID:Derivation of pluripotential embryonic stem cells from murine primordial germ cells in culture. 138 Dec 89

Leukemia inhibitory factor/differentiation-stimulating factor (LIF/D-factor), expression of its mRNA, and possible roles in bone metabolism were studied in murine primary and clonal osteoblast-like cells. Local bone-resorbing factors such as IL-1, TNF alpha, and LPS strongly induced expression of LIF/D-factor mRNA in both clonal MC3T3-E1 cells and primary osteoblast-like cells. Neither parathyroid hormone nor 1 alpha,25-dihydroxyvitamin D3 stimulated expression of LIF/D-factor mRNA. LIF/D-factor per se did not stimulate expression of its own mRNA. Appreciable amounts of LIF/D-factor were detected in synovial fluids from rheumatoid arthritis (RA) patients but not in those with osteoarthritis (OA). Simultaneous treatment with LIF/D-factor, IL-1, and IL-6 at the concentrations found in synovial fluids from RA patients greatly enhanced bone resorption, though these cytokines did not stimulate bone resorption when separately applied. This suggests that LIF/D-factor produced by osteoblasts is in concert with other bone-resorbing cytokines such as IL-1 and IL-6 involved in the bone resorption seen in the joints of RA patients. LIF/D-factor specifically bound to MC3T3-E1 cells with an apparent dissociation constant of 161 pM and 1,100 binding sites/cell. LIF/D-factor dose-dependently suppressed incorporation of [3H]thymidine into MC3T3-E1 cells. In addition, it potentiated the alkaline phosphatase activity induced by retinoic acid, though LIF/D-factor alone had no effect on enzyme activity. These results suggest that LIF/D-factor is involved in not only osteoclastic bone resorption but also osteoblast differentiation in conjugation with other osteotropic factors.
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PMID:Leukemia inhibitory factor/differentiation-stimulating factor (LIF/D-factor): regulation of its production and possible roles in bone metabolism. 161 24

We demonstrated murine leukemia inhibitory factor (mLIF) mRNA in osteoblastic MC3T3-E1 cells, but not mLIF in their conditioned medium. Recombinant mLIF had an inhibitory effect on alkaline phosphatase (ALP) activity, but not on DNA synthesis, in these mLIF-free cells. This inhibitory effect was not prostaglandin E2 dependent. mLIF also modulated the inhibitory effect of 1,25 dihydroxyvitamin D3 [1,25(OH)2D3] on ALP activity, partly via down regulation of 1,25(OH)2D3 binding sites. These results suggest that LIF may play a role in regulating osteoblast differentiation.
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PMID:Murine recombinant leukemia inhibitory factor modulates inhibitory effect of 1,25 dihydroxyvitamin D3 on alkaline phosphatase activity in MC3T3-E1 cells. 190 96

We have investigated the effect of a number of cytokines on the human acute myelomonocytic leukemic cell line, ML-1. The differentiation inducing effects of interleukins (IL-1 beta, IL-3 and IL-6), colony stimulating factors (GCSF and GMCSF), TNF, LIF and IFNg, were studied either individually or in combination. Criteria for monocytic differentiation were as follows: an increase in the percentage of cells reducing nitroblue tetrazolium (NBT) salt, an increase in the alkaline phosphatase activity as well as the appearance of macrophagic phenotype. Among all the cytokines tested, only TNF was found to induce differentiation and to inhibit growth of ML-1 cells. IL-3, IL-6, interferon gamma, GCSF and to a smaller extent IL-1 beta and GMCSF synergized the differentiation inducing activity of TNF.
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PMID:Comparative analysis of the effects of recombinant cytokines on the growth and differentiation of ML-1, a human myelogenous leukemic cell line. 768 36

Recombinant human leukemia inhibitory factor (rhLIF) is mitogenic for human bone-derived osteoblast-like cells in vitro. [3H]-thymidine incorporation into DNA was stimulated dose-dependently in a prostaglandin E2-independent manner. rhLIF exerted no effect on either the basal or 1,25(OH)2D3-induced synthesis of osteocalcin or alkaline phosphatase (AP) activity. Following treatment with rhLIF, radiolabelled cell nuclei were co-localized with AP, indicating that the mitogenic effect of rhLIF occurs on cells of the osteogenic lineage. Local generation of LIF at the human bone surface may therefore serve as a potential autocrine/paracrine mitogen for progenitor cells of the osteoblastic lineage and so could correlate with the known bone forming properties of LIF.
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PMID:Recombinant human leukemia inhibitory factor is mitogenic for human bone-derived osteoblast-like cells. 812 16

Monoclonal antibodies anti-SSEA-1 and EMA-1, and the lectins DBA and LTA, bound to the surface of large, round cells randomly distributed in the 26-day pig genital ridge. Other antibodies, SSEA-3, SSEA-4, TRA-1-60, and TRA-1-81, did not react with any cells in the pig genital ridge. SSEA-1-positive cells displayed pseudopods and appeared to migrate from the dorsal mesentery of the hindgut (18-day) to the primordium of the gonad (day 23) and entered the genital ridge by 26 days. The number of SSEA-1-positive cells associated with the dorsal mesentery and genital ridge markedly increased from the 18-day to the 26-day pig embryo. It was concluded that the SSEA-1-positive cells were primordial germ cells (PGCs). Using these markers and alkaline phosphatase histochemistry, pig PGCs derived from the 26-day genital ridge showed no proliferation when grown in STO co-culture in the presence of human LIF, bFGF and SCF.
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PMID:Identification of pig primordial germ cells by immunocytochemistry and lectin binding. 909 3

A culture system was devised to study the differentiation of bovine blastomeres. Blastomeres (2-13 per well) from embryos produced by in vitro maturation, fertilization, and culture of oocytes obtained from slaughterhouse ovaries were cultured for 10 days in 24-well culture plates on feeder layers in blastomere culture medium (BCM: equal parts tissue culture medium 199 and low-glucose Dulbecco's modified Eagle's medium with 10% fetal bovine serum). Ovine embryonic fibroblasts and STO cells were superior to bovine and mouse embryonic fibroblasts as mitotically inactivated feeder cells. Over five studies in which four blastomeres from an embryo were added to each culture well, an average of one colony per well formed from the blastomeres. The colonies continued to grow throughout the culture period, and most colonies resembled trophectoderm in their cellular characteristics, although some cultures contained a mixture of trophectoderm and endoderm. When the number of blastomeres cultured in each well was varied from 2-8, the number of colonies formed was proportional to the number of blastomeres added. Blastomeres from day 5 and day 6 embryos produced fewer colonies than did those from day 4 embryos, perhaps as a result of differentiation and tighter blastomere adhesion resulting in damage during their separation. The absence of serum did not alter the number of colonies formed. A number of growth factors, including LIF, OM, PGDF alpha, and FGF4, had no effect on the number of colonies, the size of colonies, or their alkaline phosphatase staining score beyond that provided by the feeder layer on serum when present. Blastomeres did not form colonies in the absence of feeder layers.
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PMID:Culture of blastomeres from in vitro-matured, fertilized, and cultured bovine embryos. 929 73

The primitive ectoderm of the mouse embryo arises from the inner cell mass between 4.75 and 5.25 days post coitum, around the time of implantation. Positioned at a pivotal time in development, just prior to formation of the three germ layers of the embryo proper, the primitive ectoderm responds directly to the signals generated during gastrulation. We have identified a conditioned medium, MEDII, which caused the homogeneous conversion of ES cells to a morphologically distinct cell population, termed early primitive ectoderm-like (EPL) cells. EPL cells expressed the pluripotent cell markers Oct4, SSEA1 and alkaline phosphatase. However, the formation of EPL cells was accompanied by alterations in Fgf5, Gbx2 and Rex1 expression, a loss in chimaera forming ability, changes in factor responsiveness and modified differentiation capabilities, all consistent with the identification of EPL cells as equivalent to the primitive ectoderm population of the 5.5 to 6.0 days post coitum embryo. EPL cell formation could be reversed in the presence of LIF and withdrawal of MEDII, which suggested that EPL cell formation was not a terminal differentiation event but reflected the ability of pluripotent cells to adopt distinct cell states in response to specific factors. Partial purification of MEDII revealed the presence of two separable biological activities, both of which were required for the induction and maintenance of EPL cells. We show here the first demonstration of uniform differentiation of ES cells in response to biological factors. The formation of primitive ectoderm, both in vivo and in vitro, appears to be an obligatory step in the differentiation of the inner cell mass or ES cells into cell lineages of the embryonic germ layers. EPL cells potentially represent a model for the development of lineage specific differentiation protocols and analysis of gastrulation at a molecular level. An understanding of the active components of MEDII may provide a route for the identification of factors which induce primitive ectoderm formation in vivo.
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PMID:Formation of a primitive ectoderm like cell population, EPL cells, from ES cells in response to biologically derived factors. 997 95

The de novo methylation activity is essential for embryonic development as well as embryonic stem (ES) cell differentiation, where the intensive and extensive DNA methylation was detected. In this study, we investigated the effects of a demethylating agent, 5-azacytidine (5-AzaC), on differentiated ES cells in order to study the possibility of reversing the differentiation process. We first induced differentiation of ES cells by forming embryoid bodies, and then the cells were treated with 5-AzaC. The cells showed some undifferentiated features such as stem cell-like morphology with unclear cell-to-cell boundary and proliferative responsiveness to LIF. Moreover, 5-AzaC increased the expressions of ES specific markers, SSEA-1, and alkaline phosphatase activity as well as ES specific genes, Oct4, Nanog, and Sox2. We also found that 5-AzaC demethylated the promoter region of H19 gene, a typical methylated gene during embryonic differentiation. These results indicate that 5-AzaC reverses differentiation state of ES cells through its DNA demethylating activity to differentiation related genes.
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PMID:Demethylating agent, 5-azacytidine, reverses differentiation of embryonic stem cells. 1535 5

Cultured mouse embryonic stem (ES) cells maintained under undifferentiated conditions (i.e. grown in medium containing 15% FCS and leukemia inhibitory factor--LIF) expressed mGlu5 metabotropic glutamate receptors. Activation of these receptors with quisqualate increased [Ca2+]i but only when cultures were deprived of extracellular glutamate, indicating that the receptor was saturated by the endogenous glutamate. Pharmacological blockade of mGlu5 receptors with 2-methyl-6-(phenylethynyl)pyridine (MPEP) or antisense-induced knock-down of mGlu5 receptors decreased the expression of the two main transcription factors that sustain ES cell self-renewal, i.e. Oct-4 and Nanog, as assessed by real-time PCR and immunoblotting. Exposure of ES cell cultures to MPEP also reduced alkaline phosphatase activity, a marker of undifferentiated ES cells. These data support a critical role for mGlu receptors in early development showing that mGlu5 receptors are expressed by ES cells and their activation sustains ES cell self-renewal in culture.
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PMID:Endogenous activation of mGlu5 metabotropic glutamate receptors supports self-renewal of cultured mouse embryonic stem cells. 1602 53


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