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

---

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

The effects of Osteogenic Protein-1 (OP-1, BMP-7) on the differentiation of the pluripotent mesenchymal cell line, C2C12, were examined. OP-1 at 50 ng/ml partially inhibited myotube formation in C2C12 cells, while OP-1 at 200 ng/ml completely inhibited myotube formation and induced the formation of cells displaying osteoblastic morphology. High concentrations of OP-1 elevated the alkaline phosphatase (AP) activity dramatically, both as a function of time and OP-1 concentration. Osteocalcin (OC) mRNA expression was detected as early as 8 days in OP-1-treated cultures and subsequently increased considerably. Expression of bone sialoprotein (BSP) mRNA was low in control cultures and stimulated by OP-1. Collagen type I mRNA expression was enhanced by OP-1 during the early days in culture, but gradually decreased thereafter. MyoD mRNA expression, high in control cultures, was suppressed by OP-1 in a dose- and time-dependent manner. OP-1 enhanced ActR-I mRNA expression and significantly elevated the mRNA expressions of BMP-1, BMP-4, BMP-5, GDF-6, and GDF-8. The present results indicate that OP-1 is a potent inducer of C2C12 differentiation into osteoblastic cells.
...
PMID:Osteogenic protein-1 (OP-1, BMP-7) induces osteoblastic cell differentiation of the pluripotent mesenchymal cell line C2C12. 1239 11

Silicon deficiency in animals leads to bone defects. This element may therefore play an important role in bone metabolism. Silicon is absorbed from the diet as orthosilicic acid and concentrations in plasma are 5-20 microM. The in vitro effects of orthosilicic acid (0-50 microM) on collagen type 1 synthesis was investigated using the human osteosarcoma cell line (MG-63), primary osteoblast-like cells derived from human bone marrow stromal cells, and an immortalized human early osteoblastic cell line (HCC1). Collagen type 1 mRNA expression and prolyl hydroxylase activity were also determined in the MG-63 cells. Alkaline phosphatase and osteocalcin (osteoblastic differentiation) were assessed both at the protein and the mRNA level in MG-63 cells treated with orthosilicic acid. Collagen type 1 synthesis increased in all treated cells at orthosilicic acid concentrations of 10 and 20 microM, although the effects were more marked in the clonal cell lines (MG-63, HCCl 1.75- and 1.8-fold, respectively, P < 0.001, compared to 1.45-fold in the primary cell lines). Treatment at 50 microM resulted in a smaller increase in collagen type 1 synthesis (MG-63 1.45-fold, P = 0.004). The effect of orthosilicic acid was abolished in the presence of prolyl hydroxylase inhibitors. No change in collagen type 1 mRNA level was seen in treated MG-63 cells. Alkaline phosphatase activity and osteocalcin were significantly increased (1.5, 1.2-fold at concentrations of 10 and 20 microM, respectively, P < 0.05). Gene expression of alkaline phosphatase and osteocalcin also increased significantly following treatment. In conclusion, orthosilicic acid at physiological concentrations stimulates collagen type 1 synthesis in human osteoblast-like cells and enhances osteoblastic differentiation.
...
PMID:Orthosilicic acid stimulates collagen type 1 synthesis and osteoblastic differentiation in human osteoblast-like cells in vitro. 1263 84

Estrogens have complex effects on the skeleton, including regulation of modeling and maintenance of bone mass, which vary with cell type and developmental stage. Osteoblasts are key regulators of skeletal matrix synthesis and degradation. However, whether osteocytes, osteoblasts or earlier progenitors mediate estrogen effects, and the importance of estrogen receptors (ERs) alpha and beta, remain unclear. To address estrogen response in human cells closely related to secretory osteoblasts, we studied MG63 cells with ERalpha or ERbeta reduced to low levels by stable transfection of antisense plasmids. Collagen and alkaline phosphatase expression increased with estrogen in wild-type and ERalpha-suppressed cells, but not in ERbeta-suppressed cells. Matrix secretion occurs as osteoblasts cease dividing, and, in keeping with this, cell proliferation was reduced by estrogen except in ERbeta-antisense cells. No effects of estrogen on wild type or ER-suppressed cells were seen in expression of BMP 2, the BMP antagonist noggin, or Indian hedgehog, products that regulate differentiation of osteoblasts. In contrast to expectations that estrogen would modulate bone degradation, RANKL, CSF-1, and osteoprotegerin did not respond measurably to estrogen, regardless of ER status. In keeping with this result, estrogen response was not observed in assays of osteoclast development from CD14 cells supported by wild-type or ER-silenced MG63 cells. Since estrogens are major regulators of bone degradation in vivo, estrogen effects on osteoclasts may depend on interaction with stimuli present in bone but absent in the model studied. cDNA hybridization showed that additional estrogen-binding proteins including ERRalpha and BCAR3 were expressed by MG63, but estrogen effects in ERbeta-silenced cells were small, so these proteins are either minor regulators in MG63 cells, or act in concert with stimuli in addition to estrogen. We conclude that, in the MG63 cell line, estrogen increases synthesis of matrix proteins via ERbeta, and that, in the absence of additional stimuli, these cells are not major mediators of estrogen effects on osteoclast differentiation. Further, ERalpha is probably much more important in earlier stages of skeletal development, such as growth plate response, than in osteoblasts.
...
PMID:Estrogen receptor-beta modulates synthesis of bone matrix proteins in human osteoblast-like MG63 cells. 1268 16

Collagen was covalently linked to the surface of Titanium (Ti) by a surface modification process involving deposition of a thin film from hydrocarbon plasma followed by acrylic acid grafting. The composition and properties of surface-modified Ti were investigated by a number of surface sensitive techniques: XPS, ATR-IR, atomic force microscopy and AFM force-separation curves. In vitro tests were performed to check samples cytotoxicity and the behavior of osteoblast-like SaOS-2 cells. In vivo experiments involved 12 weeks implants in rabbit muscle as general biocompatibility assessment and 1-month implants in rabbit bone to evaluate the effect of surface modification on osteointegration rate. Results of XPS measurements show how surface chemistry is affected throughout each step of the surface modification process, finally leading to a complete and homogeneous collagen overlayer on top of the Ti samples. AFM data clearly display the modification of the surface topography and of the surface area of the samples as a consequence of the grafting and coupling process. AFM force-distance curves show that the interfacial structure responds by shrinking or swelling to variations of ionic force of the surrounding aqueous environment, suggesting that the aqueous interface of the biochemically modified Ti samples has enhanced degrees of freedom as compared to the inorganic surface of plain Ti. As to biological evaluations, the biochemically modified Ti samples are safe in terms of cytotoxicity and in vivo biocompatibility assessment. SaOS-2 cells growth rate is lower on collagen modified surfaces, and no significant difference is detected in terms of alkaline phosphatase production as compared to control Ti. Importantly, implants in rabbit femur show a significant increase of bone growth and bone-to-implant contact in the case of the collagen modified samples, confirming that biochemical modifications of Ti surface can enhance the rate of bone healing as compared to plain Ti.
...
PMID:Surface engineering of titanium by collagen immobilization. Surface characterization and in vitro and in vivo studies. 1295 Oct 7

There is no ideal material for craniofacial bone repair at present. The aim of this study was to test the biocompatibility of polycaprolactone (PCL) synthesised by a novel method allowing control of molecular weight and degradation rate, with regard to it being used as matrix for a biodegradable composite for craniofacial bone repair. Human primary craniofacial cells were used, isolated from paediatric skull after surgery. Cell responses were analysed using various assays and antibody staining. Cells attached and spread on the PCL in a similar manner to the Thermanox controls as shown by phalloidin staining of F-actin. Cells maintained the osteoblast phenotype as demonstrated by alkaline phosphatase assay and antibody staining throughout the time points studied, up to 28 days. Cells proliferated on the PCL as shown by a DNA assay. Collagen-1 staining showed extensive production of a collagen-1 containing extracellular matrix, which was also shown to be mineralised by alizarin red staining. Short-term (up to 48 h) attachment studies and long-term (up to 28 days) expression of markers of the osteoblast phenotype have been demonstrated on the PCL. This new method of synthesising PCL shows biocompatibility characteristics that give it potential to be used for craniofacial bone repair.
...
PMID:Craniofacial osteoblast responses to polycaprolactone produced using a novel boron polymerisation technique and potassium fluoride post-treatment. 1455 3

Calcium phosphate ceramics with different hydroxyapatite (HA) and tricalcium phosphate (TCP) ratios have different chemical properties. Does the difference in phase composition affect osteoblast behavior? In this study, osteoblasts were cultured on 4 kinds of calcium phosphate ceramics, i.e. pure (HA), HT1 (HA/TCP, 70/30), HT2 (HA/TCP, 35/65), and pure TCP. Cell proliferation of SaOS-2 cells together with bone-related genes' mRNA expression and protein production in osteoblasts cultured on different calcium phosphate ceramics were detected at different time points. Data suggested that cell proliferation rate on TCP ceramics was lower than that on the other substrates tested. Generally, mRNA expressions for osteonectin and osteocalcin were similar among the four kinds of ceramics in most circumstances, whereas at six days, alkaline phosphatase mRNA expression was higher on HA and HT1 surfaces than on the other two materials. Collagen I mRNA expression was also affected by the phase composition of substrates. Osteocalcin and bone sialoprotein production in SaOS-2 cells was very similar no matter which ceramic surface the cells were grown upon. This study revealed that calcium phosphate ceramics substrate could support osteoblast growth and bone-related gene expression and its gene expression pattern explained the basis of the biocompatibility and bioactivity for calcium phosphate ceramics.
...
PMID:Phenotypic expression of bone-related genes in osteoblasts grown on calcium phosphate ceramics with different phase compositions. 1475 35

The aim of the study was to investigate the effect of cyclic mechanical strain on differentiation markers in the presence or absence of dexamethasone. Human bone marrow stromal cells (BMSC) from seven donors (32.5+/-6.2 years) were cultivated with (D+) or without (D-) dexamethasone. A cyclic mechanical strain with an elongation of 2% (D+2; D-2) or 8% (D+8; D-8) was applied for three days with a stimulation time of three times two hours each day. Levels of alkaline phosphatase (ALP) and osteocalcin (OC) were compared after time intervals of four and seven days. mRNA expression of Collagen I, III and Cbfa1 was investigated after one, four, and seven days. ALP levels were significantly increased in the D+8 group after four and seven days (147.1+/-6.3%; p<0.05 and 168.6+/-6,5%; p<0.03) and in the D-8 group after 7 days (197.4+/-10.4; p<0.04). Cyclic strain had a significant influence on ALP-secretion (F=7.5; p<0.01). In the D-8 group there was a significant increase in OC secretion after 4 days (140.9+/-12.5%; p<0.05).; p<0.01). The effect of stretching was significantly stronger than that of dexamethasone (F=17.2 vs. 1.8). Collagen I (Col I) expression was upregulated in D+8 cultures after 4 days (215.0+/-53.3 p<0.04) and after seven days (166.7+/-55.7; p<0.04). Collagen III (Col III) expression was upregulated in D+2 and D+8 cultures after 4 days (200.7+/-16.3 and 185.9+/-12.7; p<0.04) and after seven days (154.4+/-10.1 and 118.8+/-16.4; p<0.04). There was a significant increase of Cbfa1 expression in D+8 cultures at all investigated time intervals (day 1: 105.5+/-3.7%; day 4: 104.7+/-3.0%; day 7: 104.4+/-2.1%; p<0.03). Stretching (F=20.0; p<0.01) was a stronger contributor to Cbfa-1 expression than dexamethasone (F=12.1; p<0.01). Cyclical mechanical stimulation with 8% elongation increases ALP and OC levels and upregulates Col I and III synthesis and Cbfa1 expression. In the short term, cyclical stretching is a stronger differentiation factor than dexamethasone. Cyclical stretching and dexamethasone both enhance the osteogenic commitment of hBMSC.
...
PMID:Effects of cyclic longitudinal mechanical strain and dexamethasone on osteogenic differentiation of human bone marrow stromal cells. 1509 54

In the interest of optimizing osteogenesis in in vitro, the present study sought to determine how porcine bone marrow stromal cell (BMSc) would respond to different concentrations of hyaluronan (HY) and its different combinations with dexamethasone (Dex) and recombinant human bone morphogenic protein-2 (rhBMP-2). Cellular proliferation was determined by 3H-thymidine incorporation into DNA at both Days 2 and 7 when BMSc was cultivated with HY at concentrations of 0, 0.5, 1.0, 2.0 and 4.0 mg/ml. HY accelerated cellular proliferation when compared with cultures in the absence of HY at both Days 2 and 7. BMSc proliferation under the high HY concentration of 4 mg/ml was significantly higher than under the other, lower HY concentrations of 0.5, 1.0 and 2.0 mg/ml. When BMSc were cultivated under HY at concentrations of 0, 1.0 and 4.0 mg/ml and its 12 combinations with rhBMP-2 at concentrations of 0 and 10 ng/ml and Dex (+, -) at both Days 2 and 7, cellular responses were examined by 3H-thymidine incorporation into DNA, cellular alkaline phosphatase (ALP) activity, and pro-collagen type I C-terminal propeptide production. HY accelerated cellular proliferation irrespective of the presence of Dex and rhBMP-2. HY increased expression of ALP activity at Day 7, whereas had inhibitory effect at Day 2. HY and Dex showed an interaction on expression of ALP acitivity irrespective of the HY dose by Day 7. Collagen synthesis was inhibited by HY irrespective of the presence of other factors at both Days 2 and 7. When BMSc were cultivated with HY of 4.0 mg/ml alone, its combinations with Dex (+) and 10 ng/ml rhBMP-2, and with DMEM/FBS alone, expression of bone-related marker genes was evaluated by real-time reverse transcription-polymerase chain reaction (Real-time RT-PCR) analysis. Osteocalcin was up-regulated under both rhBMP-2 and HY-Dex-rhBMP-2 at Day 2, as also under 4 mg/ml HY, Dex, HY-Dex, Dex-rhBMP-2, and HY-Dex-rhBMP-2 by Day 7. Type 1alpha1 collagen was induced by rhBMP-2 on Day 2, and by Dex-rhBMP-2 on Day 7. Osteonectin and type X collagen was only marginally induced by HY at Day 2. Type 1alpha1 collagen and type X collagen were down-regulated in the presence of 4 mg/ml HY by Day 7. These results suggest that HY stimulates BMSc proliferation, osteocalcin gene expression, and a secretion of enzymes such as that of ALP activity in vitro. More importantly, HY can interact with Dex and rhBMP-2 to generate direct and specific cellular effects, which could be of major importance in bone tissue engineering.
...
PMID:Stimulation of porcine bone marrow stromal cells by hyaluronan, dexamethasone and rhBMP-2. 1513 Jul 22

Collagen has been extensively described as a beneficial material in bone tissue engineering due to its biocompatibility, biodegradability, low antigenicity, and high tensile strength. However, collagen scaffolds in their pure form have some drawbacks and improvements in the physical, chemical, and biologic properties of collagen are necessary to overcome those inadequacies. Recently, the selective hydrolysis of carboxyamides of asparagine and glutamine residues of collagen has been employed to increase the number of negative sites and enhance the piezoelectric properties of collagen. Anionic collagen scaffolds were prepared by use of a hydrolysis treatment for either 24 h [bovine pericardium (BP 24)] or 48 h (BP 48). Bovine osteoblasts were cultured on them and on native matrices to understand the cellular interactions responsible for the good osteoconductivity and biocompatibility reported with in vivo tests. Based on the data obtained on cell adhesion, alkaline phosphatase (ALP) and extracellular matrix macromolecule production, and cellular proliferation through histological analysis, we may conclude that the materials tested reveal sufficient biocompatibility level for bone repair. Further, the evidence of some connection between ALP activity and the mineralization process should be emphasized. BP 48 presented the most promising results stimulating in vitro mineralization, ALP production, and possible osteoblast differentiation.
...
PMID:In vitro analysis of anionic collagen scaffolds for bone repair. 1538 2

The specific structure of a dental implant's surface is often used as an argument for a better overall performance and durability. Nonetheless, it is not yet fully clear to what extent an implant's material or surface structure improves its performance. For a better understanding of the early integration-related processes, growth and initiation of mineralization of human MG-63 osteoblasts grown on glass slides or on polished (MS: machine-surfaced) or structured (SB: deep-structured) titanium surfaces were monitored. Cells were cultured under non-confluent conditions in absence and presence of osteogenic medium (OS). The 3D-architecture of growing cells was documented by confocal laser scanning microscopy (CLSM) upon fluorescently labeling for collagen I. Collagen I distribution was found comparable under all conditions. In control cultures on glass, MS and SB, cells had grown as multilayered but not yet confluent networks, which additionally comprised dome-like structures on the two Ti-surfaces. While on glass and SB cells essentially maintained this architecture also in presence of OS, three-dimensional structures on MS were--if at all--only barely visible. This was reflected also in the protein content of the cultures that was significantly lower under OS in the case of MS only. The activity of the early mineralization marker alkaline phosphatase (ALP) was higher in the controls on glass than on MS or SB. In presence of OS it was significantly higher on MS and SB than in the controls, yet not on glass. Obviously both, the surface material and the surface structure contribute--possibly synergistically--to early processes of implant integration, such as matrix formation and mineralization. The impact of such effects is discussed, in relation to implant loading and implant durability.
...
PMID:[Influence of the implant surface on the early phase of osteogenesis in vitro]. 1547 86


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---