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)

IL-6 is a 26-kDa protein cytokine with pleiotropic activities in both hematopoietic and immune systems. It is one of the major mediators of the acute phase inflammatory response. Recently it has been demonstrated that pharmacological doses of human recombinant IL-6 (rhIL-6) inhibit certain murine tumors as well as stimulate thrombopoiesis in mice, dogs, nonhuman primates, and humans. The purpose of our study was to evaluate the effects and toxicity of rhIL-6 administration in nonhuman primates with particular reference to subject age. We treated 10 female monkeys of two age groups (midle-aged and old) with rhIL-6 (15 micrograms/kg/day) for 28 days. The monkeys were observed to be somewhat lethargic and lost an average of 10% of their body weights. The white blood cell count rose transiently whereas the levels of hemoglobin and hematocrit fell significantly and remained depressed for the same period. Importantly, platelet count rose and remained elevated for the duration of treatments. Serum alkaline phosphatase levels increase significantly and certain parameters of clinical immune competence were altered by IL-6 treatment. Treatment effects were similar in both age groups, but the changes in immune functions were different between the midle-aged and old monkeys. We observed a pattern in which the middle-aged group had a significant decrease in immune functions as a result of IL-6 administration and recovered to pretreatment level despite continuous treatment, whereas the old monkeys had a more protracted but less significant decline in these same immune functions during the trial.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The influence of recombinant human interleukin-6 on blood and immune parameters in middle-aged and old rhesus monkeys. 812 61

The bone marrow stroma consists of a heterogeneous population of cells which participate in osteogenic, adipogenic, and hematopoietic events. The murine stromal cell line, BMS2, exhibits the adipocytic and osteoblastic phenotypes in vitro. BMS2 differentiation was examined in response to cytokines which share the gp130 signal transducing protein within their receptor complex. Four of the cytokines (interleukin 6, interleukin 11, leukemia inhibitory factor, and oncostatin M) inhibited hydrocortisone-induced adipocyte differentiation in a dose dependent manner based on lipid accumulation and lipoprotein lipase enzyme activity. Inhibition occurred only when the cytokines were present during the initial 24 h of the induction period; after 48 h their effects were diminished. Likewise, these cytokines increased alkaline phosphatase enzyme activity twofold in preadipocyte BMS2 cells. Both leukemia inhibitory factor and oncostatin M induced early active gene expression in resting preadipocyte BMS2 cells and decreased the steady state mRNA level of a unique osteoblastic gene marker, osteocalcin. A fifth cytokine whose receptor complex shares the gp130 protein, ciliary neurotrophic factor, did not significantly regulate stromal cell differentiation when added by itself. However, with the addition of a missing component of its receptor complex, ciliary neurotrophic factor receptor alpha protein, this cytokine also inhibited BMS2 adipogenesis. Together, these data indicate that the cytokines whose receptors share the gp130 protein can modulate stromal cell commitment to the adipocyte and osteoblast differentiation pathways.
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PMID:Regulation of bone marrow stromal cell differentiation by cytokines whose receptors share the gp130 protein. 812 83

A full-length rat gro cDNA containing the signal sequence was inserted to a plasmid/phage vector pTD-lacs which had the Escherichia coli alkaline phosphatase leader sequence down-stream of the lac promoter. After removal of the gro signal sequence by site-directed mutagenesis, the vector was introduced to E. coli JM109. The cells grown in the presence of isopropyl beta-D-thiogalactopyranoside were found to contain the recombinant mature rat Gro protein in the periplasmic space. The protein was released from the cells by osmotic shock, and could be purified to homogeneity from the periplasmic fluid by a single-step procedure using reverse phase high performance liquid chromatography. By similar procedures, recombinant human Gro alpha could be obtained. In each case, about 10 mg of purified cytokine were obtained from 1 litre of bacterial culture.
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PMID:Recombinant expression of rat and human Gro proteins in Escherichia coli. 814 7

The immune cytokine interleukin 4 has newly recognized effects on skeletal metabolism. While the interaction of many cells ultimately determines bone mass, we have examined the possibility that the osteoblast may be an IL-4 target in bone by characterizing IL-4 receptor (IL-4R) expression by MC3T3-E1 (MC3T3) murine osteoblastic cells. Based on 125I-IL-4 binding, MC3T3 cells express large numbers of IL-4 receptors (125I-IL-4 Bmax = 3,000-7,500 sites/cell, 125I-IL-4 K = 13-40 pM) with an affinity similar to the IL-4 receptor expressed by an IL-4-responsive T cell line. Monoclonal anti-IL-4R antibodies (M1) blocked specific MC3T3 125I-IL-4 binding and MC3T3 total cell RNA contained full-length IL-4R mRNA as detected by reverse transcription DNA amplification utilizing IL-4R primers and Northern blot analysis. Functionally, IL-4 treatment of MC3T3 cells resulted in increased cellular proliferation (10-20%) and inhibition of alkaline phosphatase levels (20-40%). While parathyroid hormone (PTH) exposure did not influence IL-4R levels, vitamin D3 treatment augmented MC3T3 125I-IL-4 binding, in a time-dependent manner, up to threefold after a 24 h exposure with a metabolite specificity indicating the involvement of the vitamin D receptor. Equilibrium binding studies showed that the impact of 1,25 (OH)2 D3 on MC3T3 125I-IL-4 binding was due to an increased IL-4R Bmax. Cycloheximide treatment inhibited 1,25 (OH)2 D3-induced IL-4R upregulation, suggesting that protein synthesis was required. Furthermore, the steroid increased steady-state IL-4R mRNA levels in both a time- and concentration-dependent manner. The IL-4R message half-life was not altered by 1,25 (OH)2 D3, suggesting that increased IL-4R mRNA expression resulted from increased IL-4R gene transcription. Taken together, these findings raise the possibility that IL-4's influence on mineral metabolism could be mediated by osteoblasts and that the effectiveness of this cytokine may be influenced by vitamin D3's impact on IL-4R expression.
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PMID:Murine osteoblast interleukin 4 receptor expression: upregulation by 1,25 dihydroxyvitamin D3. 822 85

The effects of interleukin-11(IL-11) on the differentiation of osteoblast precursors was tested using a bone nodule forming assay in rat calvaria cell cultures. IL-11 caused a dose dependent inhibition of nodule formation, with 500 U/ml IL-11 resulting in complete inhibition of nodule formation. IL-11 also caused a reduction in alkaline phosphatase expression in these cultures. These effects are similar to, but more potent than, the actions of IL-6 on these cells. These results indicate that IL-11 is an osteotropic cytokine and suggest that IL-11 may be an important inhibitor of bone formation in health and disease.
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PMID:Interleukin-11 inhibits bone formation in vitro. 828 26

A competitive enzyme immunoassay has been developed for the measurement of human interferon-gamma (IFN-gamma) in cell culture supernatants. The assay is based on the dose-dependent inhibitory effect of liquid phase IFN-gamma on the binding of a specific monoclonal antibody to recombinant IFN-gamma (rIFN-gamma) immobilized on microtitre plate wells. The extent of monoclonal anti-IFN-gamma inhibition was determined by the uptake of alkaline phosphatase-conjugated goat anti-mouse IgG and the subsequent development of enzyme substrate colour. Absorbance readings were taken and results for test samples were extrapolated from standard rIFN-gamma inhibition curves constructed as logit-log plots. Assay performance was assessed using three different monoclonal antibodies (clones 20G7, H-22 and GZ-4). Optimum sensitivity was achieved with the antibodies of higher affinity, 20G7 and H-22, which gave reliable quantification of IFN-gamma over a wide range of concentrations from 0.4 ng/ml (3.4 IU/ml), or less, to 250 ng/ml approximately 2000 IU/ml). The inhibition assay incorporates the advantages of specificity, reproducibility and convenience of performance which are the hallmarks of monoclonal antibody-based ELISAs. However, compared to the sandwich ELISAs previously described for human IFN-gamma, it is considerably more economical in its use of monoclonal anti-IFN-gamma, requiring < 50 ng of a single antibody per 96 well plate. It also uses relatively small volumes of test samples (50 microliters/well) which is particularly advantageous where limited amounts of cell culture supernatant are available for cytokine assays.
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PMID:A competitive inhibition ELISA for the quantification of human interferon-gamma. 831 91

Interleukin-8 (IL-8) is a polymorphonuclear leukocyte (PMN) chemoattractant and activator which mediates its effects through specific cell-surface receptors. Indirect evidence indicates that guanine nucleotide regulatory proteins (G proteins) are necessary for transmembrane signaling. The present study characterizes IL-8 receptors in isolated PMN membrane fractions and shows direct regulation of these receptors by guanine nucleotides. The binding of [125I]IL-8 to subcellular fractions of PMNs showed specific binding in a low-density membrane fraction containing alkaline phosphatase, but not in primary or secondary granules. The binding of [125I]IL-8 was rapid and reversible. The equilibrium dissociation constant (Kd) of the receptor ranged from 5.0-12.4 nM and there were 1.58-5.90 . 10(10) receptors/mg protein. The dose-response curves for the competitive binding of three different forms of IL-8 to the receptor labeled by [125I]IL-8 corresponded with their ability to produce chemotaxis and granule exocytosis in PMNs. Treatment of membranes with the nonhydrolyzable analogs of GTP, GMP-PNP and GTP gamma S, inhibited the binding of [125I]IL-8. GMP-PNP decreased the affinity of the IL-8 receptor by approx. 2-fold without altering the total receptor number. These findings demonstrate that IL-8 receptors in PMN membranes are of high affinity and are convertible to a low-affinity state in the presence of guanine nucleotides, suggesting a direct role for G proteins in transmembrane signaling by this cytokine.
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PMID:Characterization of interleukin-8 receptors in human neutrophil membranes: regulation by guanine nucleotides. 832 78

Interleukin-6 (IL-6) is a pluripotent cytokine which is made by osteoblasts, but its role in bone metabolism is uncertain. The aim of this study was to test the effect of IL-6 on bone formation in vitro using a nodule-forming assay. Osteoblast-enriched calvaria cells were isolated from 2-day-old Sprague-Dawley rats and cultured in the presence of 10(-8) M dexamethasone. After 2 days, calvaria cells were treated with recombinant human IL-6 for 72 h, washed and maintained for a further 18 days before fixation. IL-6 caused a dose-dependent inhibition of bone nodule formation, with a maximum reduction of 53% with 5000 U/ml IL-6. IL-6 also inhibited alkaline phosphatase activity in a dose-dependent manner (e.g. control: 114 +/- 9.2; IL-6: 68 +/- 10.6 nmol p-nitrophenol (pNP)/mg/min). IL-6 did not affect cell numbers during early cell growth up to 6 days but caused a small but significant reduction in cell number at confluence (8 days). These results demonstrate that IL-6 inhibits bone nodule formation by rat calvaria cells in vitro and suggest that IL-6 may inhibit osteoblast differentiation.
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PMID:Interleukin-6 inhibits bone formation in vitro. 832 17

The mRNA expression of alkaline phosphatase (ALP), myeloperoxidase (MPO), defensin and G-CSF receptor (G-CSFR) in bone marrow cells of normal individuals and myeloid disorders, with or without in vitro stimulation by myeloid cell growth factors, i.e. G-CSF, GM-CSF and IL-3, were examined as markers for myeloid cell differentiation in both mononuclear cell (MNC) and polymorphonuclear cell (PMN) fractions. Without any stimulation, ALP mRNA was expressed only in PMNs, G-CSFR mRNA in PMNs were expressed stronger than in MNCs; both MPO and defensin mRNA were expressed to the same degree in both fractions. With stimulation, the ALP mRNA expression in both fractions was strongly enhanced by G-CSF, but the expression was inhibited by GM-CSF and/or IL-3. MPO mRNA expression was stimulated by G-CSF and/or GM-CSF in MNCs. G-CSFR mRNA expression was enhanced by G-CSF in both fractions. Defensin mRNA expression was inhibited by G-CSF. In cases of myelodysplastic syndrome and chronic myelogenous leukaemia which display a suppressed maturation of myeloid cells, our results demonstrated an almost normal response to these growth factors. Our results suggest that studies on these myeloid marker mRNA expressions would provide more knowledge about the differentiation state and cytokine reactivity of myeloid cells in normal individuals as well as various disorders.
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PMID:Effects of myeloid cell growth factors on alkaline phosphatase, myeloperoxidase, defensin and granulocyte colony-stimulating factor receptor mRNA expression in haemopoietic cells of normal individuals and myeloid disorders. 856 17

In basal conditions, NB4 and HL-60, two acute promyelocytic leukemia cell lines, express high levels of tumor necrosis factor (TNF-alpha) mRNA, whereas they do not synthesize appreciable amounts of the transcripts coding for interleukin-1 beta (IL-1 beta) or interleukin-8 (IL-8). Upon granulocytic differentiation with all-trans retinoic acid (ATRA) or the combination of ATRA and granulocyte-colony-stimulating factor (G-CSF), significant amounts of IL-1 beta and IL-8 mRNAs accumulated in both cell types. These changes in mRNA levels were parallelled by the increased secretion of the two cytokines. Dexamethasone (DEX) had no effect on the induction of IL-1 beta mRNA, while it enhanced the G-CSF-, ATRA- and (ATRA+G-CSF) dependent secretion of the cytokine. In combination with ATRA and G-CSF, the corticosteroid increased the expression of leukocyte alkaline phosphatase, a late marker of granulocytic differentiation.
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PMID:Effects of dexamethasone on pro-inflammatory cytokine expression, cell growth and maturation during granulocytic differentiation of acute promyelocytic leukemia cells. 858 72


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