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Osteogenic Differentiation Markers (osteogenic + differentiation_marker)
Selected AbstractsThe proteasome inhibitor bortezomib inhibits FGF-2-induced reduction of TAZ levels in osteoblast-like cellsEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 1 2010Homare Eda Abstract Objectives:,Bortezomib (PS-341; VelcadeÔ), a proteasome inhibitor, is used as a therapeutic agent for multiple myeloma. Bortezomib has been shown to strongly induce osteoblast differentiation and elevate the levels of osteoblast-related differentiation markers in the serum of patients with myeloma. Bortezomib also reportedly increases the activity of the transcription factor, Runx2. However, the mechanism of action by which bortezomib-elevated Runx2 activity mediates osteoblast differentiation remains unclear. On the other hand, fibroblast growth factor 2 (FGF-2) is found at high levels in patients with multiple myeloma. We previously reported that FGF-2 reduces the levels of the transcriptional coactivator with PDZ-binding motif (TAZ). We therefore investigated the effects of bortezomib on TAZ protein levels in the presence of FGF-2. Methods: Osteoblastic MC3T3-E1 cells were treated with different concentrations of bortezomib in the presence or absence of FGF-2 and various biologic responses were investigated by immunoblotting, RT-PCR, quantitative PCR, and alizarin red staining. Results: We found that bortezomib inhibited FGF-2-induced reduction of TAZ levels through a pathway other than that used for proteasome inhibition, while maintaining TAZ function, which in turn, enhanced the expression of Runx2-transcribed osteogenic differentiation markers. Bortezomib also suppressed the antimineralization effect of FGF-2. Conclusions: These findings suggest that bortezomib inhibited FGF-2-induced reduction of TAZ and consequently stimulated osteogenic differentiation independently of proteasome inhibition. These findings may contribute to elucidate the osteolytic mechanism in multiple myeloma, and to the development of new drugs for multiple myeloma and other osteolytic diseases. [source] Oxysterol-induced osteogenic differentiation of marrow stromal cells is regulated by Dkk-1 inhibitable and PI3-kinase mediated signalingJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2008Christopher M. Amantea Abstract Osteoporosis and its complications cause morbidity and mortality in the aging population, and result from increased bone resorption by osteoclasts in parallel with decreased bone formation by osteoblasts. A widely accepted strategy for improving bone health is targeting osteoprogenitor cells in order to stimulate their osteogenic differentiation and bone forming properties through the use of osteoinductive/anabolic factors. We previously reported that specific naturally occurring oxysterols have potent osteoinductive properties, mediated in part through activation of hedgehog signaling in osteoprogenitor cells. In the present report, we further demonstrate the molecular mechanism(s) by which oxysterols induce osteogenesis. In addition to activating the hedgehog signaling pathway, oxysterol-induced osteogenic differentiation is mediated through a Wnt signaling-related, Dkk-1-inhibitable mechanism. Bone marrow stromal cells (MSC) treated with oxysterols demonstrated increased expression of osteogenic differentiation markers, along with selective induced expression of Wnt target genes. These oxysterol effects, which occurred in the absence of ,-catenin accumulation or TCF/Lef activation, were inhibited by the hedgehog pathway inhibitor, cyclopamine, and/or by the Wnt pathway inhibitor, Dkk-1. Furthermore, the inhibitors of PI3-Kinase signaling, LY 294002 and wortmanin, inhibited oxysterol-induced osteogenic differentiation and induction of Wnt signaling target genes. Finally, activators of canonical Wnt signaling, Wnt3a and Wnt1, inhibited spontaneous, oxysterol-, and Shh-induced osteogenic differentiation of bone marrow stromal cells, suggesting the involvement of a non-canonical Wnt pathway in pro-osteogenic differentiation events. Osteogenic oxysterols are, therefore, important small molecule modulators of critical signaling pathways in pluripotent mesenchymal cells that regulate numerous developmental and post-developmental processes. J. Cell. Biochem. 105: 424,436, 2008. © 2008 Wiley-Liss, Inc. [source] Estrogen modulates estrogen receptor , and , expression, osteogenic activity, and apoptosis in mesenchymal stem cells (MSCs) of osteoporotic miceJOURNAL OF CELLULAR BIOCHEMISTRY, Issue S36 2001Shuanhu Zhou Abstract In the mouse, ovariectomy (OVX) leads to significant reductions in cancellous bone volume while estrogen (17,-estradiol, E2) replacement not only prevents bone loss but can increase bone formation. As the E2-dependent increase in bone formation would require the proliferation and differentiation of osteoblast precursors, we hypothesized that E2 regulates mesenchymal stem cells (MSCs) activity in mouse bone marrow. We therefore investigated proliferation, differentiation, apoptosis, and estrogen receptor (ER) , and , expression of primary culture MSCs isolated from OVX and sham-operated mice. MSCs, treated in vitro with 10,7 M E2, displayed a significant increase in ER, mRNA and protein expression as well as alkaline phosphatase (ALP) activity and proliferation rate. In contrast, E2 treatment resulted in a decrease in ER, mRNA and protein expression as well as apoptosis in both OVX and sham mice. E2 up-regulated the mRNA expression of osteogenic genes for ALP, collagen I, TGF-,1, BMP-2, and cbfa1 in MSCs. In a comparison of the relative mRNA expression and protein levels for two ER isoforms, ER, was the predominant form expressed in MSCs obtained from both OVX and sham-operated mice. Cumulatively, these results indicate that estrogen in vitro directly augments the proliferation and differentiation, ER, expression, osteogenic gene expression and, inhibits apoptosis and ER, expression in MSCs obtained from OVX and sham-operated mice. Co-expression of ER,, but not ER,, and osteogenic differentiation markers might indicate that ER, function as an activator and ER, function as a repressor in the osteogenic differentiation in MSCs. These results suggest that mouse MSCs are anabolic targets of estrogen action, via ER, activation. J. Cell. Biochem. Suppl. 36: 144,155, 2001. © 2001 Wiley-Liss, Inc. [source] Differential expression of periodontal ligament-specific markers and osteogenic differentiation in human papilloma virus 16-immortalized human gingival fibroblasts and periodontal ligament cellsJOURNAL OF PERIODONTAL RESEARCH, Issue 2 2007S.-H. Pi Background and Objective:, Periodontal ligament cells and gingival fibroblasts are important in the remodeling of periodontal tissue, but human papilloma virus (HPV)16-immortalized cell lines derived from human periodontal ligament cells and gingival fibroblasts has not been characterized. The purpose of this study was to establish and differentially characterize the immortalized cell lines from gingival fibroblasts and periodontal ligament by HPV16 transfection. Material and Methods:, Cell growth, cell cycle analysis, western blot for cell cycle regulatory proteins and osteogenic differentiation markers, and reverse transcription,polymerase chain reaction for periodontal ligament-specific markers were performed. Results:, Both immortalized cell lines (immortalized gingival fibroblasts and immortalized periodontal ligament cells) grew faster than primary cultured gingival fibroblasts or periodontal ligament cells. Immortalized gingival fibroblasts and immortalized periodontal ligament cells overexpressed proteins p16 and p21, and exhibited degradation of proteins pRb and p53, which normally cause cell cycle arrest in G2/M-phase. Western blotting and reverse transcription,polymerase chain reaction for periodontal ligament-specific and osteogenic differentiation marker studies demonstrated that a cell line, designated IPDL, mimicked periodontal ligament gene expression for alkaline phosphatase, osteonectin, osteopontin, bone sialoprotein, bone morphogenic protein-2, periostin, S-100A4 and PDLs17. Conclusion:, These results indicate that IPDL and immortalized gingival fibroblast cell lines consistently retain normal periodontal ligament and gingival fibroblast phenotypes, respectively, and periodontal ligament markers and osteogenic differentiation in IPDL are distinct from immortalized gingival fibroblast cells. [source] | ||||||||||