The Experts below are selected from a list of 164196 Experts worldwide ranked by ideXlab platform
Julia M. Polak - One of the best experts on this subject based on the ideXlab platform.
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enhanced derivation of osteogenic cells from murine embryonic stem cells after treatment with ionic dissolution products of 58s bioactive sol gel glass
Tissue Engineering, 2005Co-Authors: Robert C Bielby, Russell S Pryce, Larry L. Hench, Julia M. PolakAbstract:Embryonic stem (ES) cells represent a potentially useful cell source for tissue regeneration. Previously, using factors known to enhance differentiation and mineralization of primary Osteoblasts, we were able to generate cell populations enriched with Osteoblasts from a murine ES cell source. Dexamethasone was a potent inducer of Osteoblast differentiation and the timing of stimulation markedly increased the proportion of Osteoblast lineage cells. This study examined whether inorganic stimuli derived from bioactive glasses could affect the differentiation of Osteoblasts in an ES-cell based system. Previous work has demonstrated the ability of soluble ions released from bioactive glasses undergoing dissolution in vitro to stimulate gene expression characteristic of a mature phenotype in primary Osteoblasts. We report here on the potential of soluble extracts prepared from 58S sol–gel bioactive glass to further enhance lineage-specific differentiation in murine ES cells. Differentiation of ES cells into ost...
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Enhanced derivation of osteogenic cells from murine embryonic stem cells after treatment with ionic dissolution products of 58S bioactive sol-gel glass.
Tissue engineering, 2005Co-Authors: Robert C Bielby, Russell S Pryce, Larry L. Hench, Julia M. PolakAbstract:Embryonic stem (ES) cells represent a potentially useful cell source for tissue regeneration. Previously, using factors known to enhance differentiation and mineralization of primary Osteoblasts, we were able to generate cell populations enriched with Osteoblasts from a murine ES cell source. Dexamethasone was a potent inducer of Osteoblast differentiation and the timing of stimulation markedly increased the proportion of Osteoblast lineage cells. This study examined whether inorganic stimuli derived from bioactive glasses could affect the differentiation of Osteoblasts in an ES-cell based system. Previous work has demonstrated the ability of soluble ions released from bioactive glasses undergoing dissolution in vitro to stimulate gene expression characteristic of a mature phenotype in primary Osteoblasts. We report here on the potential of soluble extracts prepared from 58S sol-gel bioactive glass to further enhance lineage-specific differentiation in murine ES cells. Differentiation of ES cells into osteogenic cells was characterized by the formation of multilayered, mineralized nodules. These nodules contained cells expressing the transcription factor runx2/cbfa-1, and deposition of osteocalcin in the extracellular matrix was detected by immunostaining. When differentiating cells were placed in an Osteoblast maintenance medium supplemented with soluble extracts prepared from bioactive glass powders, we observed increased formation of mineralized nodules (98 +/- 6%, mean +/- SEM) and alkaline phosphatase activity (56 +/- 14%, mean +/- SEM) in a pattern characteristic of Osteoblast differentiation. This effect of the glass extracts exhibited dose dependency, with alkaline phosphatase activity and nodule formation increasing with extract concentrations. Compared with medium supplemented with dexamethasone, which had previously been used to enhance Osteoblast lineage derivation, the glass extracts were as effective at inducing formation of mineralized nodules by murine ES cells. When glass extracts were used in combination with dexamethasone, a further increase in the number of nodules was observed (110 +/- 16%; cf. 83 +/- 7% for dexamethasone alone). This study demonstrates the capacity of an entirely inorganic material to stimulate differentiation of ES cells toward a lineage with therapeutic potential in tissue-engineering applications.
Li An Wu - One of the best experts on this subject based on the ideXlab platform.
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development and characterization of a mouse floxed bmp2 Osteoblast cell line that retains Osteoblast genotype and phenotype
Cell and Tissue Research, 2011Co-Authors: Li An Wu, Kevin J Donly, Stephen E. Harris, Junsheng Feng, Lynn Wang, Yan Dong Mu, Andrew Baker, Mary MacdougallAbstract:Bone morphogenetic protein 2 (Bmp2) is essential for Osteoblast differentiation and osteogenesis. Generation of floxed Bmp2 Osteoblast cell lines is a valuable tool for studying the effects of Bmp2 on Osteoblast differentiation and its signaling pathways during skeletal metabolism. Due to relatively limited sources of primary Osteoblasts, we have developed cell lines that serve as good surrogate models for the study of Osteoblast cell differentiation and bone mineralization. In this study, we established and characterized immortalized mouse floxed Bmp2 Osteoblast cell lines. Primary mouse floxed Bmp2 Osteoblasts were transfected with pSV3-neo and clonally selected. These transfected cells were verified by PCR and immunohistochemistry. To determine the genotype and phenotype of the immortalized cells, cell morphology, proliferation, differentiation and mineralization were analyzed. Also, expression of Osteoblast-related gene markers including Runx2, Osx, ATF4, Dlx3, bone sialoprotein, dentin matrix protein 1, osteonectin, osteocalcin and osteopontin were examined by quantitative RT-PCR and immunohistochemistry. These results showed that immortalized floxed Bmp2 Osteoblasts had a higher proliferation rate but preserved their genotypic and phenotypic characteristics similar to the primary cells. Thus, we, for the first time, describe the development of immortalized mouse floxed Bmp2 Osteoblast cell lines and present a useful model to study Osteoblast biology mediated by BMP2 and its downstream signaling transduction pathways.
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immortalization and characterization of mouse floxed bmp2 4 Osteoblasts
Biochemical and Biophysical Research Communications, 2009Co-Authors: Li An Wu, Guohua Yuan, Guobin Yang, Iris Ortizgonzalez, Wuchen Yang, Mary Macdougall, Kevin J DonlyAbstract:Generation of a floxed Bmp2/4 Osteoblast cell line is a valuable tool for studying the modulatory effects of Bmp2 and Bmp4 on Osteoblast differentiation as well as relevant molecular events. In this study, primary floxed Bmp2/4 mouse Osteoblasts were cultured and transfected with simian virus 40 large T-antigen. Transfection was verified by polymerase chain reaction (PCR) and immunohistochemistry. To examine the characteristics of the transfected cells, morphology, proliferation and mineralization were analyzed, expression of cell-specific genes including Runx2, ATF4, Dlx3, Osx, dentin matrix protein 1, bone sialoprotein, osteopontin, osteocalcin, osteonectin and collagen type I was detected. These results show that transfected floxed Bmp2/4 Osteoblasts bypassed senescence with a higher proliferation rate, but retain the genotypic and phenotypic characteristics similar to the primary cells. Thus, we for the first time demonstrate the establishment of an immortalized mouse floxed Bmp2/4 Osteoblast cell line.
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Immortalization and characterization of mouse floxed Bmp2/4 Osteoblasts.
Biochemical and Biophysical Research Communications, 2009Co-Authors: Li An Wu, Guohua Yuan, Guobin Yang, Wuchen Yang, Mary Macdougall, Kevin J Donly, Iris Ortiz-gonzalez, Stephen E. Harris, Shuo ChenAbstract:Generation of a floxed Bmp2/4 Osteoblast cell line is a valuable tool for studying the modulatory effects of Bmp2 and Bmp4 on Osteoblast differentiation as well as relevant molecular events. In this study, primary floxed Bmp2/4 mouse Osteoblasts were cultured and transfected with simian virus 40 large T-antigen. Transfection was verified by polymerase chain reaction (PCR) and immunohistochemistry. To examine the characteristics of the transfected cells, morphology, proliferation and mineralization were analyzed, expression of cell-specific genes including Runx2, ATF4, Dlx3, Osx, dentin matrix protein 1, bone sialoprotein, osteopontin, osteocalcin, osteonectin and collagen type I was detected. These results show that transfected floxed Bmp2/4 Osteoblasts bypassed senescence with a higher proliferation rate, but retain the genotypic and phenotypic characteristics similar to the primary cells. Thus, we for the first time demonstrate the establishment of an immortalized mouse floxed Bmp2/4 Osteoblast cell line.
Robert C Bielby - One of the best experts on this subject based on the ideXlab platform.
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enhanced derivation of osteogenic cells from murine embryonic stem cells after treatment with ionic dissolution products of 58s bioactive sol gel glass
Tissue Engineering, 2005Co-Authors: Robert C Bielby, Russell S Pryce, Larry L. Hench, Julia M. PolakAbstract:Embryonic stem (ES) cells represent a potentially useful cell source for tissue regeneration. Previously, using factors known to enhance differentiation and mineralization of primary Osteoblasts, we were able to generate cell populations enriched with Osteoblasts from a murine ES cell source. Dexamethasone was a potent inducer of Osteoblast differentiation and the timing of stimulation markedly increased the proportion of Osteoblast lineage cells. This study examined whether inorganic stimuli derived from bioactive glasses could affect the differentiation of Osteoblasts in an ES-cell based system. Previous work has demonstrated the ability of soluble ions released from bioactive glasses undergoing dissolution in vitro to stimulate gene expression characteristic of a mature phenotype in primary Osteoblasts. We report here on the potential of soluble extracts prepared from 58S sol–gel bioactive glass to further enhance lineage-specific differentiation in murine ES cells. Differentiation of ES cells into ost...
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Enhanced derivation of osteogenic cells from murine embryonic stem cells after treatment with ionic dissolution products of 58S bioactive sol-gel glass.
Tissue engineering, 2005Co-Authors: Robert C Bielby, Russell S Pryce, Larry L. Hench, Julia M. PolakAbstract:Embryonic stem (ES) cells represent a potentially useful cell source for tissue regeneration. Previously, using factors known to enhance differentiation and mineralization of primary Osteoblasts, we were able to generate cell populations enriched with Osteoblasts from a murine ES cell source. Dexamethasone was a potent inducer of Osteoblast differentiation and the timing of stimulation markedly increased the proportion of Osteoblast lineage cells. This study examined whether inorganic stimuli derived from bioactive glasses could affect the differentiation of Osteoblasts in an ES-cell based system. Previous work has demonstrated the ability of soluble ions released from bioactive glasses undergoing dissolution in vitro to stimulate gene expression characteristic of a mature phenotype in primary Osteoblasts. We report here on the potential of soluble extracts prepared from 58S sol-gel bioactive glass to further enhance lineage-specific differentiation in murine ES cells. Differentiation of ES cells into osteogenic cells was characterized by the formation of multilayered, mineralized nodules. These nodules contained cells expressing the transcription factor runx2/cbfa-1, and deposition of osteocalcin in the extracellular matrix was detected by immunostaining. When differentiating cells were placed in an Osteoblast maintenance medium supplemented with soluble extracts prepared from bioactive glass powders, we observed increased formation of mineralized nodules (98 +/- 6%, mean +/- SEM) and alkaline phosphatase activity (56 +/- 14%, mean +/- SEM) in a pattern characteristic of Osteoblast differentiation. This effect of the glass extracts exhibited dose dependency, with alkaline phosphatase activity and nodule formation increasing with extract concentrations. Compared with medium supplemented with dexamethasone, which had previously been used to enhance Osteoblast lineage derivation, the glass extracts were as effective at inducing formation of mineralized nodules by murine ES cells. When glass extracts were used in combination with dexamethasone, a further increase in the number of nodules was observed (110 +/- 16%; cf. 83 +/- 7% for dexamethasone alone). This study demonstrates the capacity of an entirely inorganic material to stimulate differentiation of ES cells toward a lineage with therapeutic potential in tissue-engineering applications.
Ryutaro Kamijo - One of the best experts on this subject based on the ideXlab platform.
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Bone morphogenetic protein 2 enhances mouse osteoclast differentiation via increased levels of receptor activator of NF-κB ligand expression in Osteoblasts
Cell and Tissue Research, 2010Co-Authors: Keita Tachi, Masamichi Takami, Ayako Mochizuki, Yoichi Miyamoto, Atsushi Yamada, Tomio Inoue, Baohong Zhao, Kazuyoshi Baba, Ryutaro KamijoAbstract:1α,25-dihydroxyvitamin D_3 [1,25(OH)_2D_3] induces osteoclast formation via induction of receptor activator of NF-κB ligand (RANKL, also called TNF-related activation-induced cytokine: TRANCE) in Osteoblasts. In cocultures of mouse bone marrow cells and Osteoblasts, 1,25(OH)_2D_3 induced osteoclast formation in a dose-dependent manner, with maximum osteoclast formation observed at concentrations greater than 10^−9 M of 1,25(OH)_2D_3. In the presence of bone morphogenetic protein 2 (BMP-2), the maximum formation of osteoclasts was seen with lower concentrations of 1,25(OH)_2D_3 (greater than 10^−11 M), suggesting that BMP-2 enhances osteoclast formation induced by 1,25(OH)_2D_3. In addition, the expressions of RANKL mRNA and proteins were induced by 1,25(OH)_2D_3 in Osteoblasts, and further upregulated by BMP-2. In mouse bone marrow cell cultures without 1,25(OH)_2D_3, BMP-2 did not enhance osteoclast differentiation induced by recombinant RANKL and macrophage colony-stimulating factor (M-CSF), indicating that BMP-2 does not target osteoclast precursors. Furthermore, BMP-2 up-regulated the expression level of vitamin D receptor (VDR) in Osteoblasts. These results suggest that BMP-2 regulates mouse osteoclast differentiation via upregulation of RANKL in Osteoblasts induced by 1,25(OH)_2D_3.
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Osteoclast differentiation induced by synthetic octacalcium phosphate through receptor activator of NF-kappaB ligand expression in Osteoblasts.
Tissue engineering. Part A, 2009Co-Authors: Masamichi Takami, Ayako Mochizuki, Keita Tachi, Yoichi Miyamoto, Osamu SUZUKI, Yoshitomo Honda, Atsushi Yamada, Takahisa Anada, Tomio Inoue, Masanori Nakamura, Baohong Zhao, Ryutaro KamijoAbstract:Synthetic octacalcium phosphate (OCP) has a potential to enhance new bone formation and exhibits biodegradable characteristics when implanted in experimentally created bone defects. The precise mechanisms of OCP biodegradation remain unclear, though histological observations have revealed that bone-resorbing osteoclasts appear and resorb implanted OCP. To investigate how osteoclasts develop around implanted OCP, we examined osteoclast differentiation using OCP crystals in vitro. Coculturing of mouse bone marrow cells and Osteoblasts in OCP-coated cell culture plates induced osteoclast differentiation, whereas that did not occur without coating. Further, addition of bone morphogenetic protein-2 significantly increased the number of osteoclasts in the OCP-coated wells. In the presence of OCP, Osteoblasts expressed receptor activator of NF-kappaB ligand (RANKL), an osteoclast differentiation factor. In addition, when half of each culture well was coated with OCP, osteoclasts were formed in both coated and noncoated areas, suggesting that soluble factors mediate osteoclast differentiation induced by OCP. Also, calcium levels in culture medium were significantly decreased in the presence of OCP, while experimental reduction of calcium from 8.0 to 5.0 mg/dL significantly induced RANKL mRNA expression. These results suggest that OCP itself decreases calcium levels around implanted OCP, which induces osteoclast differentiation through RANKL expression by Osteoblasts.
Toshihisa Komori - One of the best experts on this subject based on the ideXlab platform.
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Regulation of Osteoblast Differentiation by Runx2
Advances in Experimental Medicine and Biology, 2009Co-Authors: Toshihisa KomoriAbstract:Runx2 protein is first detected in preOsteoblasts, and the expression is upregulated in immature Osteoblasts, but downregulated in mature Osteoblasts. Runx2 is the first transcription factor required for determination of the Osteoblast lineage, while Sp7 and canonical Wnt-signaling further direct the fate of mesenchymal cells to Osteoblasts, blocking their differentiation into chondrocytes. Runx2 induces the differentiation of multipotent mesenchymal cells into immature Osteoblasts, directing the formation of immature bone, but Runx2 inhibits Osteoblast maturation and mature bone formation. Normally, the protein level of Runx2 in Osteoblasts reduces during bone development, and Osteoblasts acquire mature phenotypes, which are required for mature bone formation. Furthermore, Runx2 triggers the expression of major bone matrix genes during the early stages of Osteoblast differentiation, but Runx2 is not essential for the maintenance of these gene expressions in mature Osteoblasts.
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regulation of Osteoblast differentiation by transcription factors
Journal of Cellular Biochemistry, 2006Co-Authors: Toshihisa KomoriAbstract:Runx2, osterix, and β-catenin are essential for Osteoblast differentiation. Runx2 directs multipotent mesenchymal cells to an Osteoblastic lineage, and inhibits them from differentiating into the adipocytic and chondrocytic lineages. After differentiating to preOsteoblasts, β-catenin, osterix, and Runx2 direct them to immature Osteoblasts, which produce bone matrix proteins, blocking their potential to differentiate into the chondrocytic lineage. Runx2 inhibits Osteoblast maturation and the transition into osteocytes, keeping Osteoblasts in an immature stage. Other transcription factors including Msx1, Msx2, Dlx5, Dlx6, Twist, AP1(Fos/Jun), Knox-20, Sp3, and ATF4 are also involved in Osteoblast differentiation. To gain an understanding of bone development, it is important to position these transcription factors to the right places in the processes of Osteoblast differentiation. J. Cell. Biochem. 99: 1233–1239, 2006. © 2006 Wiley-Liss, Inc.
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overexpression of cbfa1 in Osteoblasts inhibits Osteoblast maturation and causes osteopenia with multiple fractures
Journal of Cell Biology, 2001Co-Authors: Satoru Toyosawa, Akira Yamaguchi, Tatsuya Furuichi, Naoko Kanatani, Carolina A Yoshida, Miki Himeno, Satoru Narai, Toshihisa KomoriAbstract:Targeted disruption of core binding factor α1 (Cbfa1) showed that Cbfa1 is an essential transcription factor in Osteoblast differentiation and bone formation. Furthermore, both in vitro and in vivo studies showed that Cbfa1 plays important roles in matrix production and mineralization. However, it remains to be clarified how Cbfa1 controls Osteoblast differentiation, bone formation, and bone remodelling. To understand fully the physiological functions of Cbfa1, we generated transgenic mice that overexpressed Cbfa1 in Osteoblasts using type I collagen promoter. Unexpectedly, Cbfa1 transgenic mice showed osteopenia with multiple fractures. Cortical bone, which was thin, porous, and enriched with osteopontin, was invaded by osteoclasts, despite the absence of acceleration of osteoclastogenesis. Although the number of neonatal Osteoblasts was increased, their function was impaired in matrix production and mineralization. Furthermore, terminally differentiated Osteoblasts, which strongly express osteocalcin, and osteocytes were diminished greatly, whereas less mature Osteoblasts expressing osteopontin accumulated in adult bone. These data indicate that immature organization of cortical bone, which was caused by the maturational blockage of Osteoblasts, led to osteopenia and fragility in transgenic mice, demonstrating that Cbfa1 inhibits Osteoblast differentiation at a late stage.
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regulation of Osteoblast differentiation mediated by bone morphogenetic proteins hedgehogs and cbfa1
Endocrine Reviews, 2000Co-Authors: Akira Yamaguchi, Toshihisa Komori, Tatsuo SudaAbstract:Osteoblasts arise from common progenitors with chondrocytes, muscle and adipocytes, and various hormones and local factors regulate their differentiation. We review here regulation of Osteoblast differentiation mediated by the local factors such as bone morphogenetic proteins (BMPs) and hedgehogs and the transcription factor, core-binding factor α-1 (Cbfa1). BMPs are the most potent regulators of Osteoblast differentiation among the local factors. Sonic and Indian hedgehogs are involved in Osteoblast differentiation by interacting with BMPs. Cbfa1, a member of the runt domain gene family, plays a major role in the processes of a determination of Osteoblast cell lineage and maturation of Osteoblasts. Cbfa1 is an essential transcription factor for Osteoblast differentiation and bone formation, because Cbfa1-deficient mice completely lacked bone formation due to maturation arrest of Osteoblasts. Although the regulatory mechanism of Cbfa1 expression has not been fully clarified, BMPs are an important local fa...
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Regulation of Osteoblast differentiation mediated by bone morphogenetic proteins, hedgehogs, and Cbfa1
Endocrine Reviews, 2000Co-Authors: Akira Yamaguchi, Toshihisa Komori, Tatsuo SudaAbstract:Osteoblasts arise from common progenitors with chondrocytes, muscle and adipocytes, and various hormones and local factors regulate their differentiation. We review here regulation of Osteoblast differentiation mediated by the local factors such as bone morphogenetic proteins (BMPs) and hedgehogs and the transcription factor, core-binding factor α-1 (Cbfa1). BMPs are the most potent regulators of Osteoblast differentiation among the local factors. Sonic and Indian hedgehogs are involved in Osteoblast differentiation by interacting with BMPs. Cbfa1, a member of the runt domain gene family, plays a major role in the processes of a determination of Osteoblast cell lineage and maturation of Osteoblasts. Cbfa1 is an essential transcription factor for Osteoblast differentiation and bone formation, because Cbfa1-deficient mice completely lacked bone formation due to maturation arrest of Osteoblasts. Although the regulatory mechanism of Cbfa1 expression has not been fully clarified, BMPs are an important local factor that up-regulates Cbfa1 expression. Thus, the intimate interaction between local factors such as BMPs and hedgehogs and the transcription factor, Cbfa1, is important to Osteoblast differentiation and bone formation.
