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Normal Human Osteoblasts (normal + human_osteoblast)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

The effect of deproteinized bovine bone on osteoblast growth factors and proinflammatory cytokine production

CLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2010
Paolo Amerio
Abstract Objective: To test the ability of Bio-Oss® in inducing growth factors and proinflammatory cytokines that may have a role in inflammation after grafting, bone resorption, remodeling and in the homeostasis of osteoblasts. Material and methods: Normal human osteoblasts were seeded in Petri dishes containing granules of Bio-Oss®, cells were harvested after confluency and RNA was extracted. Reverse transcriptase polymerase chain reaction was performed using specific primers for osteonectin, bone sialoprotein (BSP), bone morphogenetic protein (BMP)-2 and BMP-7, platelet-derived growth factor (PDGF), interleukin 6 (IL-6), tumor necrosis factor , (TNF-,) and integrin ,1. Glycerol-3-phosphate dehydrogenase was used as the housekeeping gene and normal human osteoblasts grown on Petri dishes without Bio-Oss® granules were used as negative controls. Results: Osteoblast grown on Bio-Oss® showed a normal RNA expression of osteonectin, integrin ,1 and PDGF. However, compared with control osteoblasts it showed a reduced expression of BSP, BMP-2 and BMP-7, IL-6 and TNF-,. Conclusions: Our findings further support the evidence that Bio-Oss® is an excellent biomaterial that does not enhance the production of proinflammatory cytokines. To cite this article: Amerio P, Vianale G, Reale M, Muraro R, Tulli A, Piattelli A. The effect of deproteinized bovine bone on osteoblast growth factors and proinflammatory cytokine production. Clin. Oral Impl. Res. 21, 2010; 650,655. doi: 10.1111/j.1600-0501.2009.01881.x [source]

Focal Adhesion Kinase pp125FAK Interacts With the Large Conductance Calcium-Activated hSlo Potassium Channel in Human Osteoblasts: Potential Role in Mechanotransduction,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2003
Roger Rezzonico
Abstract Molecular events of mechanotransduction in osteoblasts are poorly defined. We show that the mechanosensitive BK channels open and recruit the focal adhesion kinase FAK in osteoblasts on hypotonic shock. This could convert mechanical signals in biochemical events, leading to osteoblast activation. Introduction: Mechanical strains applied to the skeleton influence bone remodeling and architecture mainly through the osteoblast lineage. The molecular mechanisms involved in osteoblastic mechanotransduction include opening of mechanosensitive cation channels and the activation of protein tyrosine kinases, notably FAK, but their interplay remains poorly characterized. The large conductance K+ channel (BK) seems likely as a bone mechanoreceptor candidate because of its high expression in osteoblasts and its ability to open in response to membrane stretch or hypotonic shock. Propagation of the signals issued from the mechanosensitivity of BK channels inside the cell likely implies complex interactions with molecular partners involved in mechanotransduction, notably FAK. Methods: Interaction of FAK with the C terminus of the hSlo ,-subunit of BK was investigated using the yeast two-hybrid system as well as immunofluorescence microscopy and coimmunoprecipitation experiments with a rabbit anti-hslo antibody on MG63 and CAL72 human osteosarcoma cell lines and on normal human osteoblasts. Mapping of the FAK region interacting with hSlo was approached by testing the ability of hSlo to recruit mutated ot truncated FAK proteins. Results: To the best of our knowledge, we provide the first evidence of the physical association of FAK with the intracellular part of hslo. We show that FAK/hSlo interaction likely takes place through the Pro-1-rich domain situated in the C-terminal region of the kinase. FAK/hSlo association occurs constitutively at a low, but appreciable, level in human osteosarcoma cells and normal human osteoblasts that express endogenous FAK and hSlo. In addition, we found that application of an hypo-osmotic shock to these cells induced a sustained activation of BK channels associated to a marked increase in the recruitment of FAK on hSlo. Conclusions: Based on these data, we propose that BK channels might play a triggering role in the signaling cascade induced by mechanical strains in osteoblasts. [source]

Expression of the melatonin receptor (MT) 1 in benign and malignant human bone tumors

JOURNAL OF PINEAL RESEARCH, Issue 2 2007
Cyril D. Toma
Abstract:, The beneficial effects of melatonin on bone homeostasis have been shown in various diseases. As this indoleamine causes dose-dependent modulation of bone-forming osteoblast and bone-resorbing osteoclast activities by receptor-independent and -dependent pathways, we investigated the expression of G-protein-coupled melatonin receptors (MTs) in malignant and non-malignant human bone lesions. By TaqMan polymerase chain reaction (PCR), we analyzed 30 specimens from osteosarcoma and 11 from benign bone tumors for MT1-mRNA expression. Furthermore, we determined mRNA expression levels of the osteoclast activity-stimulating receptor activator of nuclear factor- , B ligand (RANKL) and its counterpart osteoprotegerin (OPG). Although mean MT1-mRNA levels were similar (P = 0.596) in malignant (4.39 ± 4.98-fold) and benign samples (4.64 ± 6.81-fold), the highest MT1-mRNA levels (up to 27-fold) were observed in individual osteosarcomas, particularly, in two specimens of patients with local recurrence of the tumor. Moreover, mean RANKL- and OPG-mRNA levels were similar in malignant and benign specimens (RANKL: 7.38 ± 9.61-fold versus 3.57 ± 3.11-fold, P = 0.207; OPG: 23.45 ± 32.76 versus 8.07 ± 7.23-fold, P = 0.133). Again, highest RANKL- and OPG-mRNA levels (up to 41- and 160-fold, respectively) were observed in individual osteosarcomas. Expression of MT1-mRNA was confirmed in two human osteosarcoma cell lines (HOS, MG63). High expression levels of MT1-mRNA together with low OPG-mRNA were found in both osteosarcoma cell lines, while in normal human osteoblasts and bone marrow stromal cells, high OPG-mRNA levels were associated with low MT1-mRNA levels. These data on the abundant expression of MT1-mRNA in human bone tumors and osteosarcoma cells lines suggest an important role for MT1 in bone pathology. [source]