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You searched for +publisher:"Temple University" +contributor:("Monroy, Alexandra M."). Showing records 1 – 2 of 2 total matches.

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Temple University

1. Singh, Maneet. TRANSCRIPTIONAL REGULATION OF OSTEOACTIVIN EXPRESSION BY BMP-2 IN OSTEOBLASTS.

Degree: PhD, 2011, Temple University

Cell Biology

Osteoactivin (OA) is a glycoprotein required for the differentiation of osteoblasts. In osteoblasts, Bone Morphogenetic Protein-2 (BMP-2) activated Smad1 signaling enhances OA expression. However, the transcriptional regulation of OA gene expression by BMP-2 is still unknown. The aim of this study was to characterize BMP-2-induced transcription factors that regulate OA gene expression during osteoblast differentiation. The stimulatory effects of BMP-2 on OA transcription were established by cloning the proximal 0.96kb of rat OA promoter region in a luciferase reporter vector in various osteogenic cell types. Further, by deletion and mutagenesis analyses of the cloned OA promoter, key binding sites for osteogenic transcription factors namely, Runx2, Smad1, Smad4 and homeodomain proteins (Dlx3, Dlx5 and Msx2) were identified and characterized. Utilizing specific siRNAs to knock down Runx2, Smad1, Smad4, Dlx3, Dlx5 or Msx2 proteins in osteoblasts, we found that Runx2, Smad1, Smad4, Dlx3 and Dlx5 proteins up-regulate OA transcription, whereas, Msx2 down-regulated OA gene expression. These specific effects of transcription factors on OA promoter regulation were confirmed by forced expression of transcription factors. Most notably, BMP-2-stimulated cooperative and synergistic interactions between Runx2-Smad1 proteins and Dlx3-Dlx5 proteins that up-regulate OA promoter activity. Electrophoretic mobility shift and supershift assays demonstrated that BMP-2 stimulates interactions between Runx2, Smad1 and Smad4 and homeodomain transcription factors with the OA promoter regions flanking the -585 Runx2 binding site, the -248 Smad binding site and the region between the -852 and the -843 homeodomain binding sites relative to transcription start site. The OA promoter region was occupied by Runx2 and also Dlx3 transcription factors during proliferation stages of osteoblast differentiation. As the osteoblasts progress from proliferation to matrix maturation stages of differentiation, the OA promoter was predominantly occupied by Runx2 and to a lesser extent Dlx5 in response to BMP-2. Finally, during matrix mineralization stages of osteoblast differentiation, BMP-2-induced a robust recruitment of Dlx5, Smad1, Dlx3 and Msx2 proteins with simultaneous dissociation of Runx2 from the OA promoter region. In conclusion, the BMP-2-induced osteogenic transcription factors Runx2, Smad1, Smad4, Dlx3, Dlx5 and Msx2 provide key molecular switches that regulate OA transcription during osteoblast differentiation.

Temple University – Theses

Advisors/Committee Members: Safadi, Fayez F., Popoff, Steven N., Barbe, Mary F., Sanjay, Archana, Monroy, Alexandra M., Owen, Thomas A..

Subjects/Keywords: Cellular Biology; Molecular Biology; Biology; HOMEDOMAIN PROTEIN; OSTEOACTIVIN; OSTEOBLAST DIFFERENTIATION; RUNX2; SMAD1 AND SMAD4; TRANSCRIPTIONAL REGULATION

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Singh, M. (2011). TRANSCRIPTIONAL REGULATION OF OSTEOACTIVIN EXPRESSION BY BMP-2 IN OSTEOBLASTS. (Doctoral Dissertation). Temple University. Retrieved from http://digital.library.temple.edu/u?/p245801coll10,135232

Chicago Manual of Style (16th Edition):

Singh, Maneet. “TRANSCRIPTIONAL REGULATION OF OSTEOACTIVIN EXPRESSION BY BMP-2 IN OSTEOBLASTS.” 2011. Doctoral Dissertation, Temple University. Accessed September 24, 2020. http://digital.library.temple.edu/u?/p245801coll10,135232.

MLA Handbook (7th Edition):

Singh, Maneet. “TRANSCRIPTIONAL REGULATION OF OSTEOACTIVIN EXPRESSION BY BMP-2 IN OSTEOBLASTS.” 2011. Web. 24 Sep 2020.

Vancouver:

Singh M. TRANSCRIPTIONAL REGULATION OF OSTEOACTIVIN EXPRESSION BY BMP-2 IN OSTEOBLASTS. [Internet] [Doctoral dissertation]. Temple University; 2011. [cited 2020 Sep 24]. Available from: http://digital.library.temple.edu/u?/p245801coll10,135232.

Council of Science Editors:

Singh M. TRANSCRIPTIONAL REGULATION OF OSTEOACTIVIN EXPRESSION BY BMP-2 IN OSTEOBLASTS. [Doctoral Dissertation]. Temple University; 2011. Available from: http://digital.library.temple.edu/u?/p245801coll10,135232


Temple University

2. Belcher, Joyce Yvonne. Bone Cell Autonomous Effects of Osteoactivin In Vivo.

Degree: PhD, 2012, Temple University

Cell Biology

Osteoactivin (OA) is a type I transmembrane glycoprotein initially identified in bone in 2002. The protein is synthesized, processed and heavily glycosylated by osteoblasts. Its expression is associated with increased osteoblast differentiation and matrix mineralization. To determine the role of OA in skeletal homeostasis in vivo. we utilized a mouse model with a natural mutation in the osteoactivin gene. This mutation is due to a premature stop codon, which results in the generation of a truncated 150 amino acid OA protein. This animal, which we will refer to as OA mutant, was shown by ìCT and histomorphometric analysis to have increased bone volume, trabecular thickness, and trabecular number compared to wild-type (WT) mice at 4 weeks of age, which is a time at which bone formation is most active. Histological analysis of long bones stained with TRAP (tartrate resistant acid phosphatase) and colorimetric analysis of serum TRAP 5b levels indicated that the numbers of osteoclasts are significantly increased in OA mutant samples. Interestingly, although the numbers of osteoclasts as compared to WT were higher in OA mutant mice, serum levels of C-telopeptide of type I collagen (CTX) and osteocalcin, biomarkers for bone resorption and bone formation respectively, were significantly decreased. These data suggested that in mice the presence of truncated OA protein results in increased osteoclast number, but that they are inefficient in resorbing bone and may in part contribute to the increase in bone volume in OA mutant mice in vivo. To further investigate the role of OA in osteoclast differentiation, osteoclasts were differentiated from hematopoietic stem cell progenitors ex vivo. HSCs were cultured in the presence of 50 ng/ml of M-CSF for two days and then with M-CSF and 100 ng/ml of RANKL in the presence or absence of 50 ng/ml recombinant OA. We observed a dramatic increase in multinucleated TRAP-positive osteoclasts and the number of nuclei per osteoclast in OA-treated cultures compared to control. Additionally, analysis of HSCs showed increased cell proliferation in response to exogenous OA treatment. When osteoclasts were differentiated in ex vivo cultures derived from OA mutant and WT mice, we observed decreased osteoclast number, size, and function in OA mutant compared to WT cultures. This decrease was abrogated when cultures were treated exogenously with recombinant OA. Quantitative PCR analysis of RNA isolated during osteoclast differentiation from WT and OA mutant mice reveal decreased gene expression of critical osteoclast differentiation and functional markers, which explains the osteoclast defect observed ex vivo. To investigate the role of OA in osteoblast differentiation, primary osteoblasts were derived from mesenchymal progenitors isolated from calvariae of WT and OA mutant neonatal pups. OA mutant osteoblasts were found to have decreased alkaline phosphatase (ALP) staining and activity at day 14 in culture. Furthermore when cultures were differentiated to 21 days to simulate matrix…

Advisors/Committee Members: Popoff, Steven N., Safadi, Fayez F., Barbe, Mary F., Monroy, Alexandra M., Yingling, Vanessa, Owen, Thomas A..

Subjects/Keywords: Cellular biology; Animal Model; Gpnmb; Osteoactivin; Osteoblasts; Osteoclasts; Osteopetrosis

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Belcher, J. Y. (2012). Bone Cell Autonomous Effects of Osteoactivin In Vivo. (Doctoral Dissertation). Temple University. Retrieved from http://digital.library.temple.edu/u?/p245801coll10,183061

Chicago Manual of Style (16th Edition):

Belcher, Joyce Yvonne. “Bone Cell Autonomous Effects of Osteoactivin In Vivo.” 2012. Doctoral Dissertation, Temple University. Accessed September 24, 2020. http://digital.library.temple.edu/u?/p245801coll10,183061.

MLA Handbook (7th Edition):

Belcher, Joyce Yvonne. “Bone Cell Autonomous Effects of Osteoactivin In Vivo.” 2012. Web. 24 Sep 2020.

Vancouver:

Belcher JY. Bone Cell Autonomous Effects of Osteoactivin In Vivo. [Internet] [Doctoral dissertation]. Temple University; 2012. [cited 2020 Sep 24]. Available from: http://digital.library.temple.edu/u?/p245801coll10,183061.

Council of Science Editors:

Belcher JY. Bone Cell Autonomous Effects of Osteoactivin In Vivo. [Doctoral Dissertation]. Temple University; 2012. Available from: http://digital.library.temple.edu/u?/p245801coll10,183061

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