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)

Although osteoblasts have been shown to respond to estrogens and express both isoforms of the estrogen receptor (ER alpha and ER beta), the role each isoform plays in osteoblast cell function and differentiation is unknown. The two ER isoforms are known to differentially regulate estrogen-inducible promoter-reporter gene constructs, but their individual effects on endogenous gene expression in osteoblasts have not been reported. We compared the effects of 17 beta-estradiol (E) and tamoxifen (TAM) on gene expression and matrix formation during the differentiation of human osteoblast cell lines stably expressing either ER alpha (hFOB/ER alpha 9) or ER beta (hFOB/ER beta 6). Expression of the appropriate ER isoform in these cells was confirmed by northern and western blotting and the responses to E in the hFOB/ER beta 6 line were abolished by an ER beta-specific inhibitor. The data demonstrate that (1) in both the hFOB/ER cell lines, certain responses to E or TAM (including alkaline phosphatase, IL-6 and IL-11 production) are more pronounced at the late mineralization stage of differentiation compared to earlier stages, (2) E exerted a greater regulation of bone nodule formation and matrix protein/cytokine production in the ER alpha cells than in ER beta cells, and (3) the regulated expression of select genes differed between the ER alpha and ER beta cells. TAM had no effect on nodule formation in either cell line and was a less potent regulator of gene/protein expression than E. Thus, both the ER isoform and the stage of differentiation appear to influence the response of osteoblast cells to E and TAM.
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PMID:Estrogen regulation of human osteoblast function is determined by the stage of differentiation and the estrogen receptor isoform. 1159 13

We reported previously that Ca and Pi levels are elevated and alkaline phosphatase (ALP) activity and 1alpha,25(OH)2D3 levels are reduced in chlorpromazine (CPZ)-challenged rats. In the present study, we determined the serum levels of interleukin (IL)-6 and acid phosphatase (ACP) in CPZ-challenged rats, in addition to levels of ALP protein. ALP mRNA and coccyx morphology were examined in CPZ-challenged rats as well as the effect of CPZ on 1alpha(OH)D3 production in vivo. Although Ca, Pi, IL-6, and ACP activity levels in CPZ-challenged rats were markedly increased on day 30, the elevated serum levels were restored to within normal ranges by the in vivo addition of 1alpha(OH)D3 to CPZ administration. The gain in body weight in CPZ-treated rats was significantly improved by the addition of 1alpha(OH)D3. Reduced levels of 1alpha,25(OH)2D3 in CPZ-treated rats were restored to normal levels by the administration of 1alpha(OH)D3. Moreover, the decreased ALP activity and ALP mRNA levels in the rat coccyx marrow in CPZ-treated rats were also restored by the administration of 1alpha(OH)D3 with CPZ. However, the molecular sizes of rat ALP molecules and ALP mRNA were the same for each group. Furthermore, bone morphometry showed that trabecular bone in the rat coccyx was decreased in CPZ-treated rats. However, the reduced volume of trabecular bone in CPZ-treated rats was restored by the addition of 1alpha(OH)D3 to CPZ administration. Taken together, altered bone metabolism in CPZ-treated rats can be improved by the addition of 1alpha(OH)D3.
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PMID:Altered bone turnover in chlorpromazine-challenged rats and its effect on 1alpha-hydroxyvitamin D3 administration in vivo. 1181 Apr 12

In this research we utilized tail-suspended rats as an in vivo model for bone loss studies in order to investigate the effects of the tail suspension on the structure of the suspended bones and in ex vivo cultures the activities of trabecular osteoblasts, marrow-derived osteogenic cells, and osteoclasts obtained from treated animals, compared with untreated controls. After a 5-day hind limb unloading, trabecular thinning was already evidenced in the tibial primary spongiosa. In the secondary spongiosa, the bone formation activity was reduced whereas osteoclastic parameters were not yet altered. Bone marrow-derived osteogenic cells and differentiated osteoblasts from enzymatic digestion of posterior limb trabecular bone were prepared from 5 day tail-suspended rats and from normally loaded rats as controls. Cell morphology, alkaline phosphatase (ALPH) activity, production of mineral matrix, osteocalcin, and IL-6 secretion were evaluated in both cell populations. Tail suspension reduced the osteogenic potential of stromal marrow cells and of already differentiated osteoblasts. In fact, ALP positive colonies were significantly reduced in number and were smaller in size compared with controls and bone nodules formed in permissive conditions were also significantly fewer and smaller, whereas in cultures of cells from control conditions, large mineralizing nodules were formed. Osteocalcin secretion was not affected by unloading. Finally, IL-6 concentration was increased in marrow-derived cells from treated rats compared with controls. Primary cultures of osteoclasts were obtained from the nonadherent fraction of the bone marrow of the same animals. The number of TRAP positive cells in culture from tail-suspended rats was significantly increased, as well as bone resorption activity, measured as resorbed surfaces of a suitable synthetic hydroxyapatite, compared with controls. These data clearly suggest that skeletal unloading not only reduces the osteogenic potential of osteoblastic cells but induces an increased osteoclastogenesis and osteoclast activity in ex vivo cultures. They also indicate for the first time that a possible mediator responsible for the increased osteoclastogenesis could be represented by the IL-6 whose secretion by bone marrow cells was significantly enhanced by unloading.
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PMID:Rat hindlimb unloading by tail suspension reduces osteoblast differentiation, induces IL-6 secretion, and increases bone resorption in ex vivo cultures. 1190 15

The present study has been undertaken to evaluate bone turn-over in patients with systemic lupus erythematosus (SLE) treated with glucocorticosteroids. Thirty-eight patients with definite SLE has been investigated. The following parameters have been determinated. Some proinflammatory cytokine: interleukin-IL-1 alpha (IL-1 alpha), interleukin-IL-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), granulocyte-macrophage colony stimulating factor (GM-CSF) and some biochemical markers of osteoporosis: osteocalcin (BGP), alkaline phosphatase-bone formation (AP-B), procollagen type I carboxyterminal propeptide (PICP), carboxyterminal telopeptides of type I collagen (CTx) deoxypyridinoline (Dpd) and calcium/creatinin ratio have been determined. The forearm densitometry measurement was performed in all patients. We did not notice statistically significant decrease in bone mineral content and bone mineral density in spite of long term glucocorticosteroids treatment. Based on statistically significant correlation between carboxyterminal telopeptides of type I collagen (CTx) and calcium/creatinin ratio we observed increased bone resorption in analysed group of patients.
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PMID:[Bone tissue metabolism in systematic lupus erythematosus patients treated with glucocorticosteroids]. 1199 9

Chronic crystal-associated arthropathies such as gout and pseudogout can lead to local bone destruction. Because osteoblasts, which orchestrate bone remodeling via soluble factors and cell-to-cell interactions, have been described in contact with microcrystals, particularly in uratic foci of gout, we hypothesized that microcrystals of monosodium urate monohydrate (MSUM) and of calcium pyrophosphate dihydrate (CPPD) could alter osteoblastic functions. MSUM and CPPD adhered to human osteoblastic cells (hOB) in vitro and were partly phagocytized as shown by scanning electron microscopy. MSUM and CPPD dose-dependently stimulated the production of PGE(2) in hOB as assessed by enzyme immunoassay, a response that was synergistically enhanced in the presence of IL-1. The mechanism of this synergism was, at least in part, at the level of the expression of cyclooxygenase-2 as evaluated by immunoblot analysis. MSUM and CPPD also stimulated the expression of IL-6 and IL-8 and reduced the 1,25-dihydroxyvitamin D(3)-induced activity of alkaline phosphatase and osteocalcin in hOB (with no synergism with IL-1). MSUM- or CPPD-stimulated expression of IL-6 in hOB pretreated with the selective cyclooxygenase-2 inhibitor NS-398 was increased, unlike that induced by IL-1 alone which was partially reduced. MSUM-, CPPD- or IL-1-induced expression of IL-8 was unchanged by pretreating hOB with NS-398. These results suggest that inflammatory microcrystals alter the normal phenotype of hOB, redirecting them toward reduced bone formation and amplified osteoblast-mediated bone resorption, abnormalities that could play a role in the bone destruction associated with chronic crystal-induced arthritis.
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PMID:Inflammatory microcrystals alter the functional phenotype of human osteoblast-like cells in vitro: synergism with IL-1 to overexpress cyclooxygenase-2. 1199 89

Oncostatin M (OSM) has been described as a bone-remodeling factor either stimulating osteoblast activity or osteoclast formation in vitro. To elucidate the in vivo effect of OSM on bone remodeling, we injected an adenoviral vector encoding murine OSM in knee joints of mice. OSM strongly induced interleukin (IL)-6 gene expression, a known mediator of osteoclast development. We investigated the OSM effect in wild-type and IL-6-deficient mice and found a similar degree of OSM-induced joint inflammation. Within the first week of inflammation, the periosteum along the femur and tibia increased in cell number and stained positive for the osteoblast marker alkaline phosphatase. At these sites bone apposition occurred in both strains as demonstrated by Goldner and Von Kossa staining. In vitro OSM enhanced the effect of bone morphogenetic protein-2 on osteoblast differentiation. Immunohistochemistry demonstrated expression of receptor activator of nuclear factor-kappa B ligand (RANKL) and its receptor, receptor activator of nuclear factor-kappa B (RANK), in the periosteum but osteoclasts were not detected at sites of bone apposition. Induced mRNA expression for the receptor activator of nuclear factor-kappa B ligand inhibitor osteoprotegerin probably controlled osteoclast development during OSM overexpression. Our results show that OSM favors bone apposition at periosteal sites instead of resorption in vivo. This effect was not dependent on or inhibited by IL-6.
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PMID:Adenoviral transfer of murine oncostatin M elicits periosteal bone apposition in knee joints of mice, despite synovial inflammation and up-regulated expression of interleukin-6 and receptor activator of nuclear factor-kappa B ligand. 1200 Jul 25

NF-IL6 (Nuclear factor for IL-6 expression) is involved in inflammatory reaction, expression of acute-phase proteins and cytokines, apoptosis and suppression of tumor cells, and maintenance of macrophage immunological functions. To investigate the role of highly expressed exogenous NF-IL6 in macrophage tumor cytotoxicity, a recombinant expression plasmid, pCN, which harbored the coding region of NF-IL6, was transfected into murine primary cultured peritoneal resident macrophages by an improved DEAE-dextran method. Western blot showed the high expression of NF-IL6 in these macrophages. Then the tumor cytotoxicity of the NF-IL6-overexpressing macrophages from normal and nude mice was measured by an alkaline phosphatase assay, using the human hepatocarcinoma cell line SMMC 7721 as target cells. Results showed that the overexpression of NF-IL6 enhanced the tumor cytotoxicity in both types of macrophages, demonstrating that the expression level of the NF-IL6 gene was directly related to the tumoricidal activity in these cells.
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PMID:Enhancement of Macrophage Cytotoxicity by Overexpression of Exogenous NF-IL6 Gene. 1205 86

Technetium 99m-2-methoxyisobutil-isonitrile (Tc-99m-MIBI), also called sestaMIBI, has been used successfully to detect malignant tumours at diagnosis. Recently, it has been proposed as a safe and effective tracer in patients with multiple myeloma (MM). The purpose of this study was to demonstrate the value of the Tc-99m-MIBI uptake in disease detection and to assess the correlation between the uptake of this scintigraphy agent and prognostic factors in newly diagnosed MM patients. Thirty-five untreated patients were enrolled in the study. Tc-99m-MIBI scanning was performed in 33 patients after intravenous injection of 7.4 MBq/kg. Whole-body anterior and posterior scans were obtained after 30 min, 60 min, 2 and 4 h. The correlation between known prognostic factors of MM and the intensity of Tc-99m-MIBI uptake was assessed. Our results showed seven patients with an intensity score of I0, 12 patients with I1, eight patients with I2 and six patients with a score of I3. There was a positive correlation between Tc-99m-MIBI intensity and C-reactive protein (CRP; r=0.506, P < 0.01), erythrocyte sedimentation rate (ESR; r=0.368, P < 0.05), beta2- microglobulin (beta2M; r=0.749, P < 0.001), interleukin-6 (IL-6; r=0.823, P < 0.001), soluble Interleukin-6 receptor (sIL-6r; r=0.806, P < 0.001), serum calcium (r=0.578, P < 0.001) and bone alkaline phosphatase (BAP; r=0.472, P < 0.01). An inverse correlation was found between Tc-99m-MIBI intensity and osteocalcin (OC) and type I procollagen carboxyterminal propeptide (PICP). In conclusion, the results of this study suggest that more extensive disease activity, as determined by high levels of CRP, beta2M, IL-6 and sIL-6r correlated with a higher uptake of the radiotracer.
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PMID:Correlation between the uptake of Tc-99m-sestaMIBI and prognostic factors in patients with multiple myeloma. 1206 79

Myelomatous bone disease affects about 90% patients with multiple myeloma and solitary myeloma as well. In initial stage it is manifested as osteopenia with osteoporosis or osteolytic foci, pathologic fractures followed by neurologic complications. Ethiopathogenitically a role is played by cytokine interactions with local chemokines produced by myeloma cells and activated stromal and hemopoietic cells (osteoblasts, monocytes, macrophages) resp. From the TNF-alpha family glycoprotein complexes are liberated (RANK-L), which support activation and proliferation or are inhibitory (osteoprotegerins). Similarly in the family TGF-beta several izotypes of antiinflammatory cytokines are known (the most important is TGF-beta 1 and the morphogenetic protein-2), which have a fibrotizing effect in bones, because the produced osteoid is insufficiently mineralized. The effect is a pathologic remodelation of the skeleton. In the diagnosis of multiple myeloma the immunological knowledge is used in the initial diagnosis (immunophenotypization, follow up of TNF-alpha, TGF-beta 1, IL-1, IL-6 etc). Important are also biochemistry values of increased osteoresorption (changes of calcium, parathormone, excretion of collagen fission products, osteocalcin, the bone alkaline phosphatase). In the following part the authors inform about favourable results of long-term treatment with bisphosphonates (Bonefos, Ibandronate) in combination with anti-tumor chemotherapy in 364 patients. During a 15 years observation period median survival of 94 months with a 35% probability of 10 year survival was achieved with a significant decrease of bone complications in 58% compared to 14% in the placebo group.
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PMID:[Bone changes in multiple myeloma--current etiopathogenic, diagnostic and therapeutic aspects]. 1219 8

Accumulating evidence has suggested the protective role of HDL in cardiovascular disease processes. Calcification is a common feature of atherosclerotic lesions and contributes to cardiovascular complications due to the loss of aortic resilience and function. Recent studies have suggested that vascular calcification shares several features with skeletal bone formation at the cellular and molecular levels. These include the presence of osteoblast-like calcifying vascular cells in the artery wall that undergo osteoblastic differentiation and calcification in vitro. We hypothesized that HDL may also protect against vascular calcification by regulating the osteogenic activity of these calcifying vascular cells. When treated with HDL, alkaline phosphatase activity, a marker of osteogenic differentiation of osteoblastic cells, was significantly reduced in those cells. Prolonged treatment with HDL also inhibited calcification of these cells, further supporting the antiosteogenic differentiation property of HDL when applied to vascular cells. Furthermore, HDL inhibited the osteogenic activity that was induced by inflammatory cytokines interleukin (IL)-1beta and IL-6 as well as by minimally oxidized LDL. HDL also partially inhibited the IL-6-induced activation of signal transducer and activator of transcription 3 in calcifying vascular cells, suggesting that HDL may inhibit cytokine-induced signal transduction pathways. The inhibitory effects of HDL were mimicked by lipids extracted from HDL but not by HDL-associated apolipoproteins or reconstituted HDL. Furthermore, oxidation of HDL rendered it pro-osteogenic. Taken together, these results suggest that HDL regulates the osteoblastic differentiation and calcification of vascular cells and that vascular calcification may be another target of HDL action in the artery wall.
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PMID:High-density lipoprotein regulates calcification of vascular cells. 1236 84


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