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)

Cells from fetal or neonatal skeleton can synthesize bone-like tissue in vitro. In contrast, formation of bone-like tissue in vitro by cells derived from adult animals has rarely been reported and has not been achieved using cells from bone marrow. We have explored development of bone-like tissue in vitro by bone marrow stromal cells. Marrow stromal cells obtained from 40-43-day-old Wistar rats were grown in primary culture for 7 days and then subcultured for 20-30 days. Cells were cultured in either alpha-minimal essential medium containing 15% fetal bovine serum, antibiotics, and 50 micrograms/ml ascorbic acid, or the above medium supplemented with either 10 mM Na-beta-glycerophosphate, 10(-8) M dexamethasone, or a combination of both. Cultures were examined using phase-contrast microscopy, undemineralized and demineralized tissue histology, histochemistry (for alkaline phosphatase activity), immunohistochemistry (for collagen type, osteonectin, and bone Gla-protein), scanning and transmission electron microscopy, energy dispersive X-ray microanalysis, and X-ray diffraction. Collagenous, mineralized nodules exhibiting morphological and ultrastructural characteristics similar to bone were formed in the cultures, but only in the presence of both beta-glycerophosphate and dexamethasone. Cells associated with the nodules exhibited alkaline phosphatase activity. The matrix of the nodules was composed predominantly of type-I collagen and both osteonectin and Gla-protein were present. X-ray microanalysis showed the presence of Ca and P, and X-ray diffraction indicated the mineral to be hydroxyapatite. The nodules were also examined for bone morphogenetic protein-like activity. Paired diffusion chambers containing partly demineralized nodules and fetal muscle were implanted intraperitonealy in rats. Induction of cartilage in relation to muscle was observed histologically after 40 days in the chambers. This finding provided further support for the bone-like nature of the nodules. The observations show that bone-like tissue can be synthesized in vitro by cells cultured from young-adult bone marrow, provided that the medium contains both beta-glycerophosphate and, particularly, dexamethasone.
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PMID:Bone formation in vitro by stromal cells obtained from bone marrow of young adult rats. 319 89

The object of this research is to investigate the influence of interleukin-1 (IL-1) on heterotopic ossification (HO) induced by bone morphogenetic protein (BMP). Adult mice were implanted with doses of 1, 2, 5, and 10 mg of BMP. Several local injections of 10, 100, and 1000 units of a recombinant IL-1 beta (rIL-1 beta) were administered during the morphogenetic phase of development, starting a day before operation until one week postoperation. While IL-1 acts principally on cell proliferation, BMP primarily shows cell differentiation in the form of HO. BMP-induced HO is quantitated by computer X-ray image scanning, bone ash weight, alkaline phosphatase activity, and histological methods. The area of human BMP-induced HO was completely abolished by injections of polyclonal and monoclonal anti-IL-1 antibody. Monoclonal antibody did not cross-react with the same efficiency as polyclonal with bovine BMP. Polyclonal anti-IL-1 antibody totally neutralizes bovine BMP activity. IL-1-enhanced BMP induced HO and increased the volume of new bone in a statistically significant increment.
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PMID:Experimental heterotopic bone formation induced by bone morphogenetic protein and recombinant human interleukin-1B. 326 6

Bone morphogenetic activity of osteosarcomas from 20 patients was assayed. The activity was demonstrated as ectopic bone formation on implantation of a lyophilized fraction of the tumor into athymic nude mice in 8 of 20 cases. Osteosarcomas producing bone morphogenetic protein (BMP) differed in clinical features from those not producing BMP. They were characterized radiologically by perpendicular spicules, histologically by osteoblastic type cells, and clinically by an increased serum alkaline phosphatase level, relative resistance to preoperative chemotherapy with Adriamycin (doxorubicin) plus high-dose methotrexate, and a tendency to metastasize to other bones and the lungs.
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PMID:Clinical significance of bone morphogenetic activity in osteosarcoma. A study of 20 cases. 386 Dec 32

The effects of bone morphogenetic protein (BMP), a molecule extracted from demineralized bone, were observed in organ cultures of 21-day fetal rat calvariae. The effects of BMP on cell replication in cultures of normal rat kidney (NRK) fibroblasts were studied for comparison. At concentrations of 0.1-10 micrograms/ml for periods of 24-96 hours, BMP stimulated the incorporation of 3H-thymidine into acid-insoluble residues (DNA) in calvariae by 25%-159%, and at 1-10 micrograms/ml it increased bone DNA content by 20%-23%. BMP at 1 micrograms/ml also increased the number of calvarial mitoses after colcemid arrest by 1.5-1.8-fold. The effect of BMP on calvarial DNA synthesis was observed in the periosteal bone. In contrast to its effects on DNA synthesis, BMP did not stimulate the incorporation of 3H-proline into collagenase-digestible and noncollagen protein and did not alter calvarial alkaline phosphatase activity. BMP at 1-10 micrograms/ml caused a marked increase in 3H-thymidine incorporation into DNA in cultured NRK fibroblasts and increased DNA content and cell number by 1.5-2-fold. These studies indicate that BMP stimulates DNA synthesis and cell replication in calvarial and fibroblast cultures but does not stimulate postdifferentiated bone cells in incubated calvariae.
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PMID:Effect of partially purified bone morphogenetic protein on DNA synthesis and cell replication in calvarial and fibroblast cultures. 402 62

The bone morphogenetic proteins were originally identified based on their ability to induce ectopic bone formation in vivo and have since been identified as members of the transforming growth factor-beta gene superfamily. It has been well established that the bone morphogenetic cytokines enhance osteogenic activity in bone marrow stromal cells in vitro. Recent reports have described how bone morphogenetic proteins inhibited myogenic differentiation of bone marrow stromal cells in vitro. In vivo, bone marrow stromal cells differentiate along the related adipogenic pathway with advancing age. The current work reports the inhibitory effects of the bone morphorphogenetic proteins on adipogenesis in a multipotent murine bone marrow stromal cell line, BMS2. When exposed to bone morphogenetic protein-2, the pre-adipocyte BMS2 cells exhibited the expected induction of the osteogenic-related enzyme, alkaline phosphatase. Following induction of the BMS2 cells with adipogenic agonists, adipocyte differentiation was assessed by morphologic, enzymatic, and mRNA markers. Flow cytometric analysis combined with staining by the lipophilic fluorescent dye, Nile red, was used to quantitate the extent of lipid accumulation within the BMS2 cells. By this morphologic criteria, the bone morphogenetic proteins inhibited adipogenesis at concentrations of 50 to 500 ng/ml. This correlated with decreased levels of adipocyte specific enzymes and mRNAs. The BMS2 pre-adipocytes constitutively expressed mRNA encoding bone morphogenetic protein-4 and this was inhibited by adipogenic agonists. Together, these findings demonstrate that bone morphogenetic proteins act as adipogenic antagonists. This supports the hypothesis that adipogenesis and osteogenesis in the bone marrow microenvironment are reciprocally regulated.
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PMID:Bone morphogenetic proteins inhibit adipocyte differentiation by bone marrow stromal cells. 759 60

Recombinant baculoviruses as expression vectors for Xenopus bone morphogenetic protein (xBMP)-2, 4 and 7 were generated. The conditioned medium of insect cells infected with the virus for xBMP-2 or 4 showed strong alkaline phosphatase-inducing activity in a mouse osteoblastic cell line, MC3T3-E1, although a large portion of the activity remained in the infected cells. In contrast, xBMP-7 was preferentially secreted into the medium, but had only weak activity. Conditioned media following simultaneous inoculation with the viruses for xBMP-7 and for xBMP-2 or 4 showed a remarkably increased level of activity. The increased activity was clearly separated from other peaks derived from single infection on a cation-exchange column and was found to arise from the disulfide-linked heterodimer consisting of xBMP-4 and 7 subunits by immunoblot analysis. The heterodimer also augmented osteocalcin production and parathyroid hormone-sensitivity more strongly than the homodimers. These results suggest that our expression system provides a convenient source of heterodimeric BMP with high osteogenic differentiation-inducing activity.
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PMID:Efficient expression of a heterodimer of bone morphogenetic protein subunits using a baculovirus expression system. 773 77

We recently showed that osteogenic protein-1(OP-1), a bone morphogenetic protein member of TGF-beta superfamily, induces endochondral bone formation in vivo, and stimulates growth and differentiation of osteoblasts in rat calvarial-derived cell cultures. In the present study, we examined the effect of OP-1 on cell growth and expression of markers that are characteristic of osteoblast phenotype using the clonal rat osteosarcoma cells (ROS 17/2.8). A comparison of OP-1 and TGF-beta 1 effects on cell growth showed that, both OP-1 and TGF-beta 1 inhibited DNA synthesis up to 90 percent and 60 percent of the controls at concentrations of 10 ng/ml and 1 ng/ml, respectively, in serum-free medium. In the presence of 5% serum, TGF-beta 1 did not have any significant inhibitory effects while 40 ng OP-1/ml inhibited the DNA synthesis up to 80% of the controls. Examination of collagen synthesis showed that 40 ng OP-1/ml increased the expression of type I collagen mRNA, and thus increased collagen synthesis (4-fold), as examined by collagenase-digestible protein. Evaluation of markers that are characteristic of the osteoblast phenotype demonstrated that OP-1 stimulated cAMP production in response to PTH (10-fold at 200 ng/ml), alkaline phosphatase specific activity (ALPase) (4-fold at 80 ng/ml), and osteocalcin (OC) synthesis (4.5-fold at 40 ng/ml). Northern blot analysis revealed that OP-1 increased mRNA expression for both ALPase and OC in a dose-dependent manner. These data collectively demonstrate that OP-1 suppresses cell proliferation and stimulates the expression of markers characteristic of osteoblast phenotype in rat clonal osteoblastic osteosarcoma cells (ROS 17/2.8).
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PMID:Osteogenic protein-1 (BMP-7) inhibits cell proliferation and stimulates the expression of markers characteristic of osteoblast phenotype in rat osteosarcoma (17/2.8) cells. 773 48

We examined the effect of recombinant human osteogenic protein-1 (OP-1, or bone morphogenetic protein-7), a member of the bone morphogenetic protein family, on growth and maturation of day 11, 15 and 17 chick sternal chondrocytes in high density monolayers, suspension and agarose cultures for up to 5 weeks. OP-1 dose-dependently (10-50 ng/ml) promoted chondrocyte maturation associated with enhanced alkaline phosphatase activity, and increased mRNA levels and protein synthesis of type X collagen in both the presence and absence of serum. In serum-free conditions, OP-1 promoted cell proliferation and chondrocyte maturation, without requiring either thyroid hormone or insulin, agents known to support chick chondrocyte differentiation in vitro. When grown in agarose under the same conditions, TGF-beta 1 and retinoic acid neither initiated nor promoted chondrocyte differentiation. The results demonstrate that OP-1, as the sole medium supplement, supports the maturation of embryonic chick sternal chondrocytes in vitro.
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PMID:Osteogenic protein-1 promotes growth and maturation of chick sternal chondrocytes in serum-free cultures. 773 88

The effects of bone morphogenetic protein-2 (BMP-2), -4, and -6 were tested on the differentiation of rat osteoprogenitor cells using a bone nodule-forming assay system, and the kinetics of their actions were investigated by double labeling for alkaline phosphatase (ALP) and bromodeoxyuridine (BrdU) uptake in log phase cultures. All BMPs stimulated bone nodule formation, with an optimal concentration of 25 ng/ml resulting in nodule numbers of approximately 250% of controls using BMP-4 and -6. BMP-2 showed reduced potency compared to either BMP-4 or -6. No evidence of chondrocytic differentiation was found in any of the cultures. The effect of BMPs on nodule formation was seen after only 24 h of exposure to BMPs, but only affected nodule numbers when added to early cultures. Nodule size and number of cells per nodule were increased with BMP6 only. Continuous or 24-h exposure to BMP-2 or -4 increased the number of postmitotic ALP-positive cells in log phase cultures, whereas BMP-6 increased the number of postmitotic ALP-negative cells. The results demonstrate that BMP-6, like other BMPs, can stimulate osteoblast differentiation independent of any chondrogenic effects and suggest that an early osteoprogenitor cell is an important target cell for the action of BMPs during bone induction. Overall, BMP-2 and -4 showed differences in potency in the assay systems used, but had qualitatively similar effects. In contrast, the qualitative differences found with BMP-6 suggest that BMP-6 may be acting principally on an early stage osteoprogenitor cell.
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PMID:The effects of bone morphogenetic protein-2, -4, and -6 on differentiation of rat osteoblast cells in vitro. 775 Apr 91

The implantation of bone morphogenetic protein (BMP) into muscular tissues induces ectopic bone formation at the site of implantation. To investigate the mechanism underlying this process, we examined whether recombinant bone morphogenetic protein-2 (BMP-2) converts the differentiation pathway of the clonal myoblastic cell line, C2C12, into that of osteoblast lineage. Incubating the cells with 300 ng/ml of BMP-2 for 6 d almost completely inhibited the formation of the multinucleated myotubes expressing troponin T and myosin heavy chain, and induced the appearance of numerous alkaline phosphatase (ALP)-positive cells. BMP-2 dose dependently induced ALP activity, parathyroid hormone (PTH)-dependent 3',5'-cAMP production, and osteocalcin production at concentrations above 100 ng/ml. The concentration of BMP-2 required to induce these osteoblastic phenotypes was the same as that required to almost completely inhibit myotube formation. Incubating primary muscle cells with 300 ng/ml of BMP-2 for 6 d also inhibited myotube formation, whereas induced ALP activity and osteocalcin production. Incubation with 300 ng/ml of BMP-2 suppressed the expression of mRNA for muscle creatine kinase within 6 h, whereas it induced mRNA expression for ALP, PTH/PTH-related protein (PTHrP) receptors, and osteocalcin within 24-48 h. BMP-2 completely inhibited the expression of myogenin mRNA by day 3. By day 3, BMP-2 also inhibited the expression of MyoD mRNA, but it was transiently stimulated 12 h after exposure to BMP-2. Expression of Id-1 mRNA was greatly stimulated by BMP-2. When C2C12 cells pretreated with BMP-2 for 6 d were transferred to a colony assay system in the absence of BMP-2, more than 84% of the colonies generated became troponin T-positive and ALP activity disappeared. TGF-beta 1 also inhibited myotube formation in C2C12 cells, and suppressed the expression of myogenin and MyoD mRNAs without inducing that of Id-1 mRNA. However, no osteoblastic phenotype was induced by TGF-beta 1 in C2C12 cells. TGF-beta 1 potentiated the inhibitory effect of BMP-2 on myotube formation, whereas TGF-beta 1 reduced ALP activity and osteocalcin production induced by BMP-2 in C2C12 cells. These results indicate that BMP-2 specifically converts the differentiation pathway of C2C12 myoblasts into that of osteoblast lineage cells, but that the conversion is not heritable.
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PMID:Bone morphogenetic protein-2 converts the differentiation pathway of C2C12 myoblasts into the osteoblast lineage. 779 24


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