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)

Fibronectin, a plasma protein immunologically identical with a major surface protein of normal fibroblasts, was found to bind to collagen and gelatin. A solid phase enzyme immunoassay was used for the binding tests. Collagen, gelatin or various control proteins were adsorbed to a plastic surface. Binding of fibronectin was detected using purified fibronectin antibodies conjugated to alkaline phosphatase. Circulating fibronectin and fibronectin obtained from fibroblast cultures both showed specific binding to collagen and gelatin. Preparative affinity chromatography of plasma on gelatin coupled to Sepharose gave electrophoretically and immunologically pure fibronectin in high yields. Malignantly transformed fibroblasts lack surface fibronectin. Our findings suggest the possibility that this results in a lack of anchorage to the surrounding intercellular matrix, which could contribute to the malignant growth behavior.
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PMID:Binding of soluble form of fibroblast surface protein, fibronectin, to collagen. 90 79

Pulp cells from human permanent molars were isolated and established in culture; 40% showed positive alkaline phosphatase staining. When incubated with 50 micrograms/ml of ascorbic acid and 10 mM of beta-glycerophosphate, the cells formed a mineralized extracellular matrix; they could thus have the potential to differentiate into odontoblast-like cells in vitro. Collagen synthesis was analysed by SDS interrupted gel electrophoresis, Northern blot and slot blot: the cells produced predominantly (approximately 99%) type I collagen and only trace amount of type III collagen. The ratio of alpha 1 (I) to alpha 2(I) procollagen chains was about 68:32, indicating that no significant amount of collagen type I trimer was synthesized in this system. The ratios of alpha 1(I), alpha 2(I) and alpha 1(III) procollagen mRNAs were about 61:25:1; these were compatible with the ratios of corresponding procollagen alpha chains. In addition, a novel 5.8 kb pro alpha 1(III) mRNA was detected. These observations indicate that collagen synthesis in these cultured pulp cells was regulated at the transcriptional level.
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PMID:Collagen gene expression in human dental pulp cell cultures. 128 29

Collagen type 1 is the most abundant protein of bone. Serum levels of type 1 procollagen carboxy-terminal extension peptide (Procoll-1-C) may give a measure of the rate of synthesis of the collagen of bone and be therefore a marker of bone turnover. We have studied 38 patients with predialysis chronic renal failure; 14 of them were under long-term treatment with 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] for prevention of secondary hyperparathyroidism. In all patients a transiliac bone biopsy for histomorphometry and determination of dynamic parameters was performed following double tetracycline labeling. In addition serum Procoll-1-C, intact and C-terminal parathyroid hormone (PTH), osteocalcin and alkaline phosphatase were determined. In the patients not receiving 1,25(OH)2D3, serum levels of Procoll-1-C were higher than normal. Procoll-1-C did not correlate with any of the humoral parameters, including serum creatinine, nor with static histomorphometric parameters. Contrarily to osteocalcin, the collagen type 1 marker correlated significantly with all dynamic parameters. Treatment with 1,25(OH)2D3 was accompanied by lower levels of osteocalcin, iPTH (n.s.), osteoblastic surface and by normal levels of Procoll-1-C (p < 0.001, compared to untreated patients), without substantial change in bone formation parameters (bone formation rate). In conclusion Procoll-1-C in predialysis chronic renal failure is a marker of bone turnover unparalleled by other markers. 1,25(OH)2D3 administration is associated with lower serum levels of the peptide unaccompanied by a decrement of bone formation parameters, therefore with an apparently better utilization of collagen type 1 in the mineralization process.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Procollagen type I C-terminal extension peptide in predialysis chronic renal failure. 148 72

Metabolic acidosis induces net calcium flux (JCa) from cultured neonatal mouse calvariae through physicochemical and cell-mediated mechanisms. To determine the role of osteoblasts in acid-induced JCa, collagen synthesis and alkaline phosphatase activity were assessed in calvariae incubated in reduced pH and bicarbonate medium, a model of metabolic acidosis (Met), and compared with controls (Ctl). Collagen synthesis fell from 30.5 +/- 1.1 in Ctl to 25.1 +/- 0.4% with Met, and alkaline phosphatase decreased from 403 +/- 25 in Ctl to 298 +/- 21 nmol Pi.min-1.mg protein-1 with Met. During acidosis JCa was correlated inversely with percent collagen synthesis (r = -0.743, n = 11, P = 0.009) and with alkaline phosphatase activity (r = -0.453, n = 22, P = 0.034). To determine the role of osteoclasts in acid-induced JCa, osteoclastic beta-glucuronidase activity was determined in Ctl and Met in the absence or presence of the osteoclastic inhibitor calcitonin (CT, 3 x 10(-9) M). Met increased beta-glucuronidase (5.9 +/- 0.2) compared with Ctl (4.6 +/- 0.3 micrograms phenolphthalein released.bone-1.h-1), whereas CT inhibited beta-glucuronidase in both Ctl and Met (3.1 +/- 0.2 and 3.5 +/- 0.3, respectively). During acidosis JCa was correlated directly with beta-glucuronidase activity (r = 0.683, n = 42, P less than 0.001). Thus the cell-mediated component of JCa during acidosis in vitro appears to result from a combination of inhibited osteoblastic and stimulated osteoclastic activity.
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PMID:Acidosis inhibits osteoblastic and stimulates osteoclastic activity in vitro. 155 61

To investigate the effect of lipopolysaccharide (LPS) on phagocytic activity of collagen fibrils by periodontal fibroblasts, we studied rat molar gingival connective tissue and periodontal ligament under light and electron microscopy after topical application of LPS (5 mg/ml in physiological salt solution (PS)) on the gingival sulcus. Phagocytic activity of collagen fibrils by fibroblasts was evaluated by counting the number of collagen-containing vacuoles inside fibroblasts that were present within a defined area (1200 microns2). Values obtained from fibroblasts in the subepithelial connective tissue, the region near the alveolar crest, and the middle region of periodontal tissue were compared. Periodontal ligament fibroblasts showed increased phagocytosis of the collagen fibrils from 3 hours to 1 day after topical LPS application, but no differences were observed in the gingival tissue. The intracytoplasmic vacuoles containing collagen fibrils were of various sizes and shapes, showing positive for acid phosphatase and/or alkaline phosphatase reaction. Collagen phagocytic activity of the fibroblasts in the middle region of the periodontal ligament also increased after PS treatment. However, this was significantly less than that observed in LPS-treated animals (p less than 0.01). This study indicates that LPS may enhance the degradation of collagen by stimulating the phagocytic activity of the periodontal ligament fibroblasts.
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PMID:Enhanced collagen phagocytosis by rat molar periodontal fibroblasts after topical application of lipopolysaccharide--ultrastructural observations and morphometric analysis. 160 30

Collagen breakdown, and thus bone resorption, can now be assessed by measuring the urinary excretion of the collagen crosslinks, pyridinoline (Pyd) and deoxypyridinoline (Dpd). In a pilot study we measured Pyd and Dpd in 20 patients with breast cancer, ten with known bone metastases and ten with no recognised metastases in bone or elsewhere after 1 year's subsequent follow up. Eight out of the ten patients with metastases had crosslink excretion values higher than the reference interval, but so did some patients without known metastatic disease. For both crosslinks there was a clear correlation with serum alkaline phosphatase activity measured at about the same time. We consider that measurement of urinary collagen crosslink assays may have a place in the early detection of metastatic spread to bone.
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PMID:Pyridinium crosslinks as markers of bone resorption in patients with breast cancer. 193 10

Conditions were defined for promoting cell growth, hypertrophy, and extracellular matrix mineralization of a culture system derived from embryonic chick vertebral chondrocytes. Ascorbic acid supplementation by itself led to the hypertrophic phenotype as assessed by respective 10- and 15-fold increases in alkaline phosphatase enzyme activity and type X synthesis. Maximal extracellular matrix mineralization was obtained, however, when cultures were grown in a nutrient-enriched medium supplemented with both ascorbic acid and 20 mM beta-glycerophosphate. Temporal studies over a 3-wk period showed a 3-4-fold increase in DNA accompanied by a nearly constant DNA to protein ratio. In this period, total collagen increased from 3 to 20% of the cell layer protein; total calcium and phosphorus contents increased 15-20-fold. Proteoglycan synthesis was maximal until day 12 but thereafter showed a fourfold decrease. In contrast, total collagen synthesis showed a greater than 10-fold increase until day 18, a result suggesting that collagen synthesis was replacing proteoglycan synthesis during cellular hypertrophy. Separate analysis of individual collagen types demonstrated a low level of type I collagen synthesis throughout the 21-d time course. Collagen types II and X synthesis increased during the first 2 wk of culture; thereafter, collagen type II synthesis decreased while collagen type X synthesis continued to rise. Type IX synthesis remained at undetectable levels throughout the time course. The levels of collagen types I, II, IX, and X mRNA and the large proteoglycan core protein mRNA paralleled their levels of synthesis, data indicating pretranslational control of synthesis. Ultrastructural examination revealed cellular and extracellular morphology similar to that for a developing hypertrophic phenotype in vivo. Chondrocytes in lacunae were surrounded by a well-formed extracellular matrix of randomly distributed collagen type II fibrils (approximately 20-nm diam) and extensive proteoglycan. Numerous vesicular structures could be detected. Cultures mineralized reproducibly and crystals were located in extracellular matrices, principally associated with collagen fibrils. There was no clear evidence of mineral association with extracellular vesicles. The mineral was composed of calcium and phosphorus on electron probe microanalysis and was identified as a very poorly crystalline hydroxyapatite on electron diffraction. In summary, these data suggest that this culture system consists of chondrocytes which undergo differentiation in vitro as assessed by their elevated levels of alkaline phosphatase and type X collagen and their ultrastructural appearance.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Gene expression and extracellular matrix ultrastructure of a mineralizing chondrocyte cell culture system. 199 93

Normal rat osteoblasts in culture undergo a developmental sequence consisting of a proliferation period in which high levels of the histone and collagen type I genes are expressed, followed by periods of matrix maturation [high levels of alkaline phosphatase (AP)] and mineralization that signal a high level of production of osteopontin (OP) and osteocalcin (OC). Since these parameters are regulated by vitamin D, the effects of both short term and chronic treatment with 1,25-dihydroxyvitamin D3 were examined during osteoblast growth and differentiation. In acute studies, during the proliferation period, histone mRNA (reflecting DNA synthesis) was inhibited (20-60%). Matrix Gla protein (MGP) and OP mRNA were significantly elevated during proliferation (30- and 15-fold), in contrast to OC which is not expressed and was not induced by hormone treatment. OP and MGP remained stimulated throughout the developmental sequence, but to a lesser degree (from 6- to 10-fold). Collagen and AP mRNA were inhibited by hormone at their peak levels of expression, but were stimulated at their lowest basal levels in the mineralization period. OC expression, which was initiated at the onset of mineralization, was stimulated 13- to 15-fold when basal levels were low, then from 6- to 8-fold by hormone throughout its period of expression. In chronic studies a different profile of gene expression was observed. When hormone treatment was initiated during the proliferation period on day 6, type I collagen and AP expression were suppressed, mineralized nodules did not develop, and induced levels of OP and OC gene expression did not occur. When chronic treatment was initiated on day 20 after the development of a mineralized matrix, OC, but not collagen and OP, levels were stimulated by the hormone. This observation is consistent with the requirement of a competent or mineralized bone matrix for expression of OC. In contrast, MGP expression was stimulated in the chronic vitamin D-treated cultures similar to acute treatments. Taken together these studies demonstrate that vitamin D, a physiological mediator of bone formation and remodelling, can both positively and negatively regulate expression of osteoblast phenotypic markers as a function of duration of hormone treatment and basal levels of gene expression, which is a reflection of bone matrix competency and the differentiated state of the osteoblast.
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PMID:Pleiotropic effects of vitamin D on osteoblast gene expression are related to the proliferative and differentiated state of the bone cell phenotype: dependency upon basal levels of gene expression, duration of exposure, and bone matrix competency in normal rat osteoblast cultures. 199 68

Osteoblast-like cells are commonly found in the vicinity of osteoclasts formed in long-term human bone marrow cultures, and they are believed to be derived from osteogenic cell precursors belonging to the stromal cell system. This paper describes a new culture method for human osteoblasts from the adherent cell population of long-term human mononuclear bone marrow cultures. The cells obtained exhibited all the classic characteristics of osteoblasts. They contained high intracellular concentrations of alkaline phosphatase and they secreted the osteoblast-specific marker bone Gla protein. Collagen production was mainly (95-98%) procollagen type I propeptide and only minute quantities of procollagen type III propeptide were detectable by radioimmunoassay in the conditioned medium. After eight weeks the cells formed a mineralized matrix on exposure to beta-glycerophosphate and ascorbic acid. This system provides a model for the study of osteoblast differentiation in vitro and may form the basis for the use of defined media in bone cell cultures due to the presence of high concentrations of osteoblast precursors.
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PMID:Formation of osteoblast-like cells from human mononuclear bone marrow cultures. 201 40

Effects of transforming growth factor (TGF)-beta, epidermal growth factor (EGF), insulin, 1, 25-dihydroxyvitamin D3 (1, 25 (OH)2D3), and parathyroid hormone (PTH) on the proliferation and differentiation of clonal dental pulp cells of rats were investigated. Interaction between growth factors (TGF-beta and EGF) and two hormones insulin and 1, 25 (OH)2D3, which have been noticed to accelerate the differentiation of the cells, were also studied, and the following results were obtained: 1) TGF-beta decreased alkaline phosphatase (ALPase) activity in a dose-dependent manner, and the inhibitory effect was not blocked by indomethacin, suggesting that the effect of TGF-beta on the cells may not be mediated by prostaglandins. Inhibitory effects of ALPase antagonists (L-phenylalanine, L-homoarginine, levamisole) on the activity were not affected by TGF-beta. TGF-beta showed no evident effect on the DNA synthesis (incorporation of [3H] thymidine) and collagen synthesis (incorporation of [2, 3-3H] proline into the collagenase-digestible protein) of the cells. 2) EGF stimulated the incorporation of [3H] thymidine and inhibited the ALPase activity. The inhibitory effect was not blocked by indomethacin, indicating that the EGF effect is not mediated by prostaglandins. Collagen synthesis was significantly inhibited by EGF. 3) Insulin showed a weak but significant inhibition of the DNA synthesis. Insulin increased the ALPase activity evidently, and accelerated the collagen synthesis significantly. 4) The vitamin 1, 25 (OH)2D3 significantly increased the ALPase activity though no significant changes were observed in the DNA synthesis and collagen synthesis. 5) PTH had no evident effect on the DNA synthesis and ALPase activity, but did tend to accelerate the collagen synthesis. 6) A study on the interaction between insulin and EGF or TGF-beta revealed that the acceleration of DNA synthesis induced by EGF was inhibited when the factor was combined with insulin, and the increase in ALPase activity elicited by insulin was inhibited by EGF and weakened by TGF-beta significantly when these factors were added simultaneously with the insulin. Or viewed another way, the inhibitory effect of EGF or TGF-beta on the ALPase activity was antagonized by insulin. The accelerative action of insulin on collagen synthesis was antagonized by EGF and potentiated by TGF-beta. 7) A study on the interaction between 1, 25 (OH)2D3 and EGF or TGF-beta revealed that 1, 25 (OH)2D3 inhibited the accelerating effect of EGF on the DNA synthesis and that the increasing effect of 1, 25 (OH)2D3 on ALPase activity was strongly inhibited by EGF.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Effects of various growth factors and hormones on clonal rat pulp cells]. 213 79


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