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)

Prostaglandin E2 (PGE2) and alkaline phosphatase (ALP) have often been measured in gingival crevicular fluid (GCF) as possible indicators of gingival inflammation and bone metabolism. Osteocalcin (OC), a major component of bone matrix, is mainly produced by osteoblasts, and could also be considered as a marker of bone turnover. The aims of this preliminary study were to examine if OC was present in GCF and to assess the relationships of OC, PGE2 and ALP in GCF to periodontal conditions. GCF samples were collected with durapore strips from 34 healthy, 72 gingivitis and 118 periodontitis sites in 17 subjects. ELISA techniques were used for the determinations of OC and PGE2. ALP was measured spectrophotometrically by using p-nitrophenyl phosphate as substrate. Total amounts and concentrations of PGE2 and ALP were significantly higher in periodontitis as compared to healthy and gingivitis sites, and were significantly and positively correlated with probing depth (PD) and gingival index (GI). OC was present in GCF from both healthy and diseased sites with mean concentrations more than ten times greater than normal serum levels. Total OC amounts from strips soaked with GCF from periodontitis sites were significantly higher than those found in healthy and gingivitis sites. When the data were expressed as concentrations, OC showed significantly positive correlations with GI, but not with PD. However, total amounts of OC significantly correlated with both clinical parameters. OC, PGE2 and ALP were found to have significantly positive correlations with each other, both when expressed as total amounts and concentrations. These data suggest that a significant amount of OC present in GCF is produced locally by periodontal tissues.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Osteocalcin, prostaglandin E2 and alkaline phosphatase in gingival crevicular fluid: their relations to periodontal status. 803 77

An in vitro model was developed for the investigation of bone cell mineralization processes. Out-grown cells of explanted human nasal bone fragments were selected into three lineages and one of them, the osteoblast-enriched line, was partially characterized. A large number of cells of this line stained readily for alkaline phosphatase. They produced prostanoids, PGl2, PGF2 alpha and PGE2, and osteocalcin in the presence of 1,25(OH)2D3. Cells synthesized collagen and mineralized the developed extracellular matrix. This latter line seems to be appropriate as a model system to find effective compounds which increase bone calcification.
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PMID:Model for in vitro investigation of bone mineralization. 807 26

When endometrial stromal cells from rat uteri sensitized for the decidual cell reaction are cultured in vitro, they undergo decidualization, as indicated by increased alkaline phosphatase (ALP) activity. Prostaglandin E2 (PGE2) stimulates this increase in activity. To determine the role of cAMP in the stimulation, we examined the effect of 2':5'-dideoxyadenosine (DDA), an inhibitor of adenylate cyclase, on the ability of PGE2 to increase ALP activity. As indicated by [3H]cAMP accumulation in endometrial stromal cells preincubated with [3H]adenine, DDA inhibited PGE2-stimulated synthesis of cAMP in a concentration-dependent manner. Furthermore, DDA caused a significant decrease in the PGE2-induced ALP activity on day 3 of culture. Dibutyryl cAMP overrode this inhibition. The effect of DDA was not mimicked by adenosine, which had a stimulatory effect on ALP activity in the non-stimulated cultures and no significant effect in PGE2-stimulated cultures. Thus the inhibitory effect of DDA on PGE2-stimulated ALP activity is unlikely to be mediated by adenosine-related receptors. These results suggest that cAMP is an essential, but not necessarily the only, intracellular messenger of PGE2 in endometrial stromal cells during decidualization. The isozymes of cAMP-dependent protein kinase (PKA) mediating the effect of cAMP were assessed by using cAMP analogues directed at selective sites of PKA isozymes. Synergistic activation of ALP activity in endometrial stromal cells by pairs of analogues directed at types I and II PKA suggested that both types were functionally important during decidualization.
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PMID:Prostaglandin E2, cAMP and cAMP-dependent protein kinase isozymes during decidualization of rat endometrial stromal cells in vitro. 821 Apr 42

Although the primary skeletal action of exogenous calcitonin is to inhibit bone resorption, calcitonin also has effects on bone formation. In-vitro data indicate that the latter may include direct effects on bone cells of osteoblastic lineage. In the current studies, we examined the effects of calcitonin on cyclic adenosine monophosphate (cAMP) and PGE2 synthesis and 45Ca uptake in human osteosarcoma cells, specifically, TE-85 cells and subpopulations of SaOS-2 cells with low-, intermediate-, and high-steady-state levels of skeletal alkaline phosphatase (ALP) activity. Since previous in-vivo studies had shown that calcitonin could acutely decrease skeletal ALP activity in rat periosteal osteoblasts, we also measured the effects of calcitonin treatment on ALP specific activity. Neither salmon nor human calcitonin altered the net synthesis of cAMP or PGE2 by SaOS-2 cells, but human calcitonin gene-related peptide increased both (P < .001 and P < .005, respectively). Both salmon and human calcitonin had short-term effects to alter ALP activity in TE-85 and SaOS-2 cells. The effects were different in SaOS-2 subpopulations with different pretreatment ALP levels. Four hours of exposure to salmon calcitonin had dose-dependent, biphasic effects on ALP levels in SaOS-2 cells with intermediate pretreatment ALP levels, increasing ALP at doses between 0.16 and 1.6 nmol/L (P < .005) and decreasing ALP at higher concentrations (P < .05). Both salmon and human calcitonin, but not human calcitonin gene-related peptide, also had short-term effects to increase net 45Ca uptake by SaOS-2 cells; these effects were dose-dependent and long-lasting.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Calcitonin acutely increases net 45Ca uptake and alters alkaline phosphatase specific activity in human osteosarcoma cells. 838 75

This report documents characterization of five osteogenic cell subpopulations of bone marrow stroma. The clonally derived cell lines were isolated from the parental line MBA-15 known to express osteoblastic-associated features in vitro and to form bone in vivo. The latter, presumably "arrested" at a particular stage along the osteogenic lineage, are useful models to study the processes involved in the differentiation of bone forming cells. The clones differ in their morphology, proliferation rate, quantities and distribution of extracellular matrix proteins, levels of alkaline phosphatase activity and activation of adenylate cyclase by parathyroid hormone and/or prostaglandin E. These properties have been retained during prolonged growth and subculturing through many passages. MBA-15.4 is a presumptive preosteoblast with a fibroblast-like appearance; it proliferates rapidly, synthesizes equal amounts of collagen and noncollagenous proteins, and produces constitutively low levels of alkaline phosphatase. This clone has PGE2-stimulated adenylate cyclase activity and a very low constitutive response to PTH. On the other hand, MBA-15.6 has a large polygonal morphology with limited proliferative potential, synthesizes twice as much noncollagenous proteins as collagen, has high alkaline phosphatase activity, and responds strongly to PTH. The characteristics of the other clones place them between these two categories. The effects of 10(-7) M dexamethasone or 10(-12)-10(-8) M 1,25 dihydroxyvitamin D3 on growth and differentiation further strengthen the variance between these clones. The different in vitro characteristics of the various clones were directly reflected in their bone formation ability in vivo. When transplanted under the renal capsule, MBA-15.33 formed a thick fibrous tissue, MBA-15.4 formed small foci of bone, and MBA-15.6 formed massive woven bone at the same period of time.
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PMID:Marrow stroma-derived osteogenic clonal cell lines: putative stages in osteoblastic differentiation. 838 1

Ossification of the posterior longitudinal ligament of the spine (OPLL) is a common cause of spinal canal stenosis and myelopathy in Orientals. OPLL is characterized by heterotopic new bone formation in ligamentous tissue. To investigate the pathogenesis of OPLL, human posterior longitudinal ligament cells were cultured and their in vitro morphological and biochemical characteristics were studied. Cell cultures from control subjects with normal spinal ligaments did not show any osteoblastic properties. In contrast, cell lines (OG1-OG5) obtained from an OPLL patient showed several different phenotypic characteristics for osteoblasts. OG1 cells showed typical osteoblast-like phenotypic characteristics (i.e., in vitro calcification, high alkaline phosphatase [ALP] activity, and elevation of cAMP levels by parathyroid hormone [PTH]). All cell lines (OG1-OG5) responded to PTH and PGE2 by markedly increasing cAMP levels, ALP activities varied among the cell lines. The OG1 and OG2 cells exhibited a high level of ALP activity. Compared with cell lines from the non-ossification group, the activities were higher in the OG3 and OG4 cells, but not significantly in the OG5 cells. Only in the OG3 cells, CT caused an increase in cAMP level and ALP activity, and its stimulatory effects demonstrated that CT had a direct, in vitro action on ligament cells of OPLL patients to stimulate osteoblastic differentiation. It is clear that some cells from ligaments with OPLL had several phenotypes characteristic of osteoblasts, but cells from ligaments without ossification did not show any osteoblastic properties. This observation is considered to be an important clue to understanding the pathophysiology of OPLL.
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PMID:Characterization of cultured cells derived from ossification of the posterior longitudinal ligament of the spine. 839 54

Prostaglandin E2 (PGE2) increases the number of mineralized nodules that form in cultures of rat calvarial (RC) cells. The purpose of our study was to characterize PGE2-inducible osteogenic colony forming units (CFU-Os) by determining their number, the cell populations from which they were released, their specific responsive period to PGE2, and their proliferating and differentiating characteristics under the stimulation of PGE2. Limiting dilution analysis was used to determine the number of PGE2-inducible CFU-Os. Sequential digestion of intact rat parietal bones with collagenase isolated 5 subpopulations of RC cells that were used to estimate the cell populations where PGE2-inducible CFU-Os resided. The responsive period of PGE2-inducible CFU-Os to PGE2 was evaluated by treating cultures of mixed RC cells for all possible combinations of days 1-10, 11-20, and 21-30. PGE2 effects on proliferation and differentiation of CFU-Os were evaluated by comparing the DNA synthesis and AP activity in subpopulations I and IV on days 3, 6, and 9. Results showed: (1) PGE2-inducible CFU-Os represent 0.27% of cells in the mixed RC population, (2) the majority of determined and PGE2-inducible CFU-Os were found in the subpopulations released during the 60-100 min digestion periods, (3) the response of PGE2-inducible CFU-Os is limited to the first 10 days of culture, and (4) PGE2-stimulated nodule formation is associated with an early increase in DNA synthesis and a sustained increase in alkaline phosphatase activity. We conclude that, functionally, PGE2-inducible CFU-Os are slowly proliferating AP negative cells primarily found in the subpopulations III-V. PGE2 stimulates them to proliferate and become AP+, and function as determined CFU-Os to form mineralized nodules in vitro.
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PMID:Functional characterization of prostaglandin E2 inducible osteogenic colony forming units in cultures of cells isolated from the neonatal rat calvarium. 855 78

PGE2 is one of the key molecules in the osteoblast. It is the major prostanoid in the bone, and its production is under the control of both systemic and local factors. PGE2 has been reported to have multiple actions in the osteoblast, such as growth promotion and cell differentiation. To better understand the action of PGE2 in the osteoblast, we determined the PGE receptor subtypes in MC3T3-E1, an osteoblastic cell line derived from the normal mouse calvaria. Northern blot analysis revealed that EP1 and EP4 subtypes are expressed in MC3T3-E1. In contrast, EP3 subtype was not detected by either Northern blot analysis or RT-PCR. The contribution of each subtype was evaluated by studying the effects of subtype-specific analogs on osteoblastic function at confluency and 5 days after confluency. An EP1 agonist, 17-phenyl-omega-trinor PGE2, increased DNA synthesis and decreased alkaline phosphatase activity. 11-Deoxy-PGE1, and EP2 and EP4 agonist, decreased DNA synthesis and increased alkaline phosphatase activity at both stages. Butaprost, an EP2-selective agonist, showed effects similar to those of 11-deoxy-PGE1 only at confluency. Another and more differentiated osteoblastic marker, osteocalcin production, was detectable and was stimulated by 11-deoxy-PGE1 only 5 days after confluency. The exposure of these cells to EP1 agonist changed the cell shape to a more fibroblastic appearance. These results indicate that EP1, EP4, and probably EP2 are present in MC3T3-E1 cells; EP1 promotes cell growth, and EP2 and EP4 mediate differentiation of the osteoblast. Furthermore, the decreased response to EP2-specific agonist 5 days after confluency suggests that the expression of PGE receptor subtype is dependent on the stage of osteoblastic differentiation. This is the first report to determine PGE receptor subtypes in the bone.
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PMID:Prostaglandin E receptor subtypes in mouse osteoblastic cell line. 861 4

The role of glucocorticoids in bone formation presents a problem because although pharmacological doses in vivo give rise to osteoporosis, physiological concentrations are required for osteoblast (OB) differentiation in vitro. To try and rationalize this dichotomy, we investigated the effect of dexamethasone on the recruitment of OB precursors present in bone marrow. Using the CFU-f assay, we can measure (1) total colony formation; (2) the osteoblastic differentiation of the colonies defined as their ability to express alkaline phosphatase, synthesize collagen, and to calcify; and (3) colony expansion as either average colony surface area or average colony number. In control cultures and in the presence of 10(-10)-10(-9) M dexamethasone, colony formation and total cell number was maximal, but the addition of PGE2 had no effect on colony number and very few colonies expressed the OB phenotype. In the presence of 10(-8)-10(-7) M dexamethasone, colony numbers and total cell numbers were reduced but were increased by the addition of PGE2, the average colony cell number and surface area were relatively unchanged and a proportion of the colonies expressed APase, calcified and synthesized collagen. In cultures containing 10(-6)-10(-5) M dexamethasone, colony numbers were further reduced but were stimulated by the addition of PGE2 and some colonies differentiated; however, colony expansion was dramatically reduced by up to 80%. These results suggest that physiological levels of glucocorticoids are necessary for OB differentiation and allow the control of OB recruitment by PGE2. High levels of glucocorticoids drastically reduce proliferation of the OB precursors leading to glucocorticoid-induced osteoporosis.
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PMID:The role of glucocorticoids and prostaglandin E2 in the recruitment of bone marrow mesenchymal cells to the osteoblastic lineage: positive and negative effects. 869 91

It has been reported that periodontal ligament cells (PDLC) show osteoblastic phenotypes in culture. In most previous studies, PDLC have been obtained from the tooth root surface, however, a new method in which PDLC are obtained from the coagulum after tooth extraction has been proposed recently. To compare PDLC from tooth surface with these from coagulum, PDLC from both sources were cultured and examined. PDLC from both sources responded to PTH or PGE2 increasing cAMP and showed high alkaline phosphatase (ALP) activity. Some PDLC cultures produced mineralized tissues and these mineralizing cultures showed high ALP activity with high gene expression level of type I collagen, bone sialoprotein, and osteopontin in comparison with non-mineralizing cultures. PDLC from both sources expressed various osteoblastic or cementoblastic phenotypes and seemed to contain heterogenous mesenchymal cell population with various differentiation potentials. However, the frequency of cellular transmigration, rate of mineralized tissue formation, increased level of cAMP that responded to PTH or PGE2, and osteopontin expression pattern were different between PDLC from both sources. These differences indicate that PDLC cultures from coagulum contain more immature cells than PDLC from tooth surface.
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PMID:[Characterization of rat periodontal ligament cells in culture]. 874 17


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