DYNAMICS OF ASSEMBLY OF BONE MATRIX PROTEINS

Summary

Principal Investigator: Sarah L Dallas
Abstract: DESCRIPTION (provided by applicant): The extracellular matrix (ECM) has been viewed as a static three dimensional scaffold that supports cells and tissues. However, our recent molecular imaging studies in living osteoblasts have shown that the ECM is highly dynamic and that ECM molecules form structures that continually undergo movement and deformation, mediated by cell-generated mechanical forces. These studies also suggest a novel role for cell movement in ECM assembly and reorganization. Fibronectin is one of the earliest proteins to be assembled into the ECM and facilitates assembly of other matrix proteins. In the previous funding cycle, using fibronectin null cell culture models and targeted gene deletion in osteoblasts, it was shown that fibronectin is essential for assembly of multiple bone ECM components, including type I collagen, fibrillin-1, Latent TGF2 binding protein-1, decorin and biglycan and is also required for normal mineralization. Fibronectin depletion also inhibits osteoblast differentiation. Fibronectin's effects on differentiation can be rescued by supplementation with BMP2, whereas its effects on ECM assembly and mineralization cannot, suggesting that fibronectin may regulate osteoblast differentiation via ECM targeting of osteogenic growth factors. Based on these observations, the proposed studies are centered on two main hypotheses. The first is that fibronectin is a multifunctional regulator of osteoblast differentiation and function through its effects as a central orchestrator for assembly of bone ECM proteins and through its role in ECM regulation of growth factor activity. The second is that dynamic cell movement is essential for the assembly and reorganization of bone ECM proteins. To test these hypotheses, in vitro and in vivo approaches will be used in combination with live cell imaging. Aim 1 will define the cascade of assembly of bone ECM proteins and its integration with cell and matrix dynamics. This will be done using fibronectin null osteoblast models in conjunction with live cell molecular imaging of bone ECM proteins and quantification of cell and fibril dynamics by computational analysis. Aim 2 will further define the role of fibronectin in osteoblast differentiation through regulation of BMP signaling. Live cell imaging techniques will also be used with osteoblast/osteocyte lineage reporters and fluorescent probes for ECM components to determine how osteoblast differentiation and BMP signaling is dynamically integrated with ECM assembly and reorganization. Aim 3 will use novel imaging probes to determine the dynamics of collagen assembly into the ECM of osteoblasts and the role of fibronectin in collagen deposition in vitro and in vivo. The studies will provide fundamental insights, from a dynamic perspective, into the mechanisms of assembly of bone ECM and how the ECM regulates osteoblast function. The data generated will significantly advance our understanding of the molecular and dynamic mechanisms underlying bone formation and have key implications for skeletal diseases such as osteoporosis, arthritis, osteogenesis imperfecta and bone diseases related to ECM proteins. PUBLIC HEALTH RELEVANCE: This research is relevant to public health as it will provide highly novel insights into the dynamic processes by which the bone extracellular matrix (i.e. the protein scaffold outside the cells onto which mineral is deposited) is assembled. We will for the first time dynamically image the assembly process by which key bone matrix proteins are deposited in living bone cells and determine how the motile properties of the cells contribute to the building of the protein scaffold for mineral deposition. As these studies will significantly advance our mechanistic understanding the process of bone formation, the research has implications for treatment of osteoporosis, osteogenesis imperfecta and metabolic bone diseases.
Funding Period: 2004-09-10 - 2015-08-31
more information: NIH RePORT

Top Publications

  1. pmc Time lapse imaging techniques for comparison of mineralization dynamics in primary murine osteoblasts and the late osteoblast/early osteocyte-like cell line MLO-A5
    Sarah L Dallas
    School of Dentistry, Department of Oral Biology, University of Missouri at Kansas City, 650 E 25th Street, Kansas City, MO 64108, USA
    Cells Tissues Organs 189:6-11. 2009
  2. pmc Dynamics of the transition from osteoblast to osteocyte
    Sarah L Dallas
    Department of Oral Biology, School of Dentistry, University of Missouri, Kansas City, Missouri, USA
    Ann N Y Acad Sci 1192:437-43. 2010
  3. pmc The biological function of DMP-1 in osteocyte maturation is mediated by its 57-kDa C-terminal fragment
    Yongbo Lu
    Department of Biomedical Sciences, Baylor College of Dentistry, Texas A and M Health Science Center, Dallas, TX 75246, USA
    J Bone Miner Res 26:331-40. 2011
  4. ncbi Live imaging of bone cell and organ cultures
    Sarah L Dallas
    School of Dentistry Department of Oral Biology, University of Missouri, Kansas City, MO, USA
    Methods Mol Biol 816:425-57. 2012
  5. pmc Studying osteocytes within their environment
    Duncan J Webster
    Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
    Bone 54:285-95. 2013
  6. pmc The osteocyte: an endocrine cell ... and more
    Sarah L Dallas
    PhD, Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri Kansas City, 650 East 25th Street, Kansas City, Missouri 64108
    Endocr Rev 34:658-90. 2013

Research Grants

  1. Cellular Senescence and Aging
    James L Kirkland; Fiscal Year: 2013
  2. The Influence of PTH during Exercise on Bone Quality
    JOSEPH DANIEL GARDINIER; Fiscal Year: 2013
  3. NIDCR Individual Predoctoral Dental Scientist Fellowship
    JOSHUA PADOVANO; Fiscal Year: 2013
  4. BIOGENESIS OF EXTRACELLULAR MATRIX
    Bjorn Reino Olsen; Fiscal Year: 2013
  5. Hydrogels for hMSC delivery &engraftment
    Andres J Garcia; Fiscal Year: 2013
  6. Osseo-reparative, integrin-specific materials
    Andres J Garcia; Fiscal Year: 2013
  7. Microengineered Osteons for Bone Tissue Engineering
    Yunzhi Yang; Fiscal Year: 2013
  8. The Role of FKBP10 in Recessive Osteogenesis Imperfecta
    Caressa Lietman; Fiscal Year: 2013
  9. OXYGEN SENSING AND OSTEOGENESIS
    Thomas L Clemens; Fiscal Year: 2013
  10. Complex Nanocomposites for Bone Regeneration
    Antoni P Tomsia; Fiscal Year: 2013

Detail Information

Publications6

  1. pmc Time lapse imaging techniques for comparison of mineralization dynamics in primary murine osteoblasts and the late osteoblast/early osteocyte-like cell line MLO-A5
    Sarah L Dallas
    School of Dentistry, Department of Oral Biology, University of Missouri at Kansas City, 650 E 25th Street, Kansas City, MO 64108, USA
    Cells Tissues Organs 189:6-11. 2009
    ..These studies provide a novel approach for analyzing mineralization kinetics that will enable us to dissect in a time-specific manner the essential players in the mineralization process...
  2. pmc Dynamics of the transition from osteoblast to osteocyte
    Sarah L Dallas
    Department of Oral Biology, School of Dentistry, University of Missouri, Kansas City, Missouri, USA
    Ann N Y Acad Sci 1192:437-43. 2010
    ..Changes in motile properties of the cell may be key in the transition from osteoblast to osteocyte, as reflected in the altered expression of many molecules involved in cytoskeletal function...
  3. pmc The biological function of DMP-1 in osteocyte maturation is mediated by its 57-kDa C-terminal fragment
    Yongbo Lu
    Department of Biomedical Sciences, Baylor College of Dentistry, Texas A and M Health Science Center, Dallas, TX 75246, USA
    J Bone Miner Res 26:331-40. 2011
    ..These results show that the 57-kDa C-terminal fragment is the functional domain of DMP-1 that controls osteocyte maturation and phosphate metabolism...
  4. ncbi Live imaging of bone cell and organ cultures
    Sarah L Dallas
    School of Dentistry Department of Oral Biology, University of Missouri, Kansas City, MO, USA
    Methods Mol Biol 816:425-57. 2012
    ....
  5. pmc Studying osteocytes within their environment
    Duncan J Webster
    Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
    Bone 54:285-95. 2013
    ....
  6. pmc The osteocyte: an endocrine cell ... and more
    Sarah L Dallas
    PhD, Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri Kansas City, 650 East 25th Street, Kansas City, Missouri 64108
    Endocr Rev 34:658-90. 2013
    ..As we continue to search for new therapeutics, in addition to the osteoclast and the osteoblast, the osteocyte should be considered in new strategies to prevent and treat bone disease. ..

Research Grants62

  1. Cellular Senescence and Aging
    James L Kirkland; Fiscal Year: 2013
    ..Our approach will provide timely, innovative, and clinically relevant interventional results based on addressing the fundamental question of the role of cellular senescence that has remained unanswered for many years. ..
  2. The Influence of PTH during Exercise on Bone Quality
    JOSEPH DANIEL GARDINIER; Fiscal Year: 2013
    ..This interdisciplinary mentorship will contribute to the career development of the applicant to becoming an independent investigator under the F32 Kirschstein/NRSA award. ..
  3. NIDCR Individual Predoctoral Dental Scientist Fellowship
    JOSHUA PADOVANO; Fiscal Year: 2013
    ..This knowledge would greatly assist in developing novel, tissue engineered therapies for pathological conditions of dental and craniofacial tissues. ..
  4. BIOGENESIS OF EXTRACELLULAR MATRIX
    Bjorn Reino Olsen; Fiscal Year: 2013
    ....
  5. Hydrogels for hMSC delivery &engraftment
    Andres J Garcia; Fiscal Year: 2013
    ..Finally, because of the transformative potential of MSC, this research will have broad significance and impact to many regenerative medicine applications. ..
  6. Osseo-reparative, integrin-specific materials
    Andres J Garcia; Fiscal Year: 2013
    ..Collectively, these studies will establish novel bioactive materials that enhance bone formation and implant integration for improved bone repair in various clinical applications. ..
  7. Microengineered Osteons for Bone Tissue Engineering
    Yunzhi Yang; Fiscal Year: 2013
    ..It is expected that this project will generate a new paradigm in bone tissue engineering by enabling the formation of complex microstructures such as osteon-like units with vascular channels within cortical bone. ..
  8. The Role of FKBP10 in Recessive Osteogenesis Imperfecta
    Caressa Lietman; Fiscal Year: 2013
    ..The National Institute of Dental and Craniofacial Research is the recipient organization of this fellowship because OI and Bruck syndrome are characterized by craniofacial phenotypes. ..
  9. OXYGEN SENSING AND OSTEOGENESIS
    Thomas L Clemens; Fiscal Year: 2013
    ..These findings should lead to better understanding of precise communication between angiogenesis and osteogenesis and aid in the design of new therapies to accelerate bone healing following injury ..
  10. Complex Nanocomposites for Bone Regeneration
    Antoni P Tomsia; Fiscal Year: 2013
    ..The present standard of care for such defects may be altered to eliminate bone grafts, decrease risks to patients, improve quality of life, and increase the armamentarium of the clinician. ..
  11. Development of Osteogenic Oxysterols for Local Bone Formation
    Farhad Parhami; Fiscal Year: 2013
    ....
  12. Mineralization of the matrix in disease and health
    PETER S ROWE; Fiscal Year: 2013
    ..Design PHEX synthetic peptides as tools to probe the role of ASARM peptides and PHEX in health and disease. ..
  13. Chemical Structure Effects on Bone Response to Mechanical Load
    MICHAEL DAVID MORRIS; Fiscal Year: 2013
    ..Controlled partial replacement of hydrogen ion with deuterium ion will be used to provide a range of collagen conformation changes. ..
  14. Intersection of TGF-b and SOST in the Regulation of Load-induced Bone Formation
    Jacqueline Nguyen; Fiscal Year: 2013
    ..Clearer understanding of pathways involved in mechanosensitive bone formation would provide targets for drug development for treating bone loss due to disuse like in edentulism. ..
  15. Stress Hormones and Chondrogenic Vascular Calcification
    JODI FRANCES EVANS; Fiscal Year: 2013
    ..abstract_text> ..
  16. PKC delta as a central mediator of osteogenic signaling
    ATUM BUO; Fiscal Year: 2013
    ....
  17. Injectable Anabolic Biomaterials for Bone Regeneration
    LAKSHMI SREEDHARAN NAIR; Fiscal Year: 2013
    ..If successful, the injectable lactoferrin based delivery vehicle could have a significant impact in the clinical translation of cell based therapeutic strategies by addressing some of its current limitations. ..
  18. FUNCTION AND REGULATION OF OSTEONECTIN IN BONE
    Anne M Delany; Fiscal Year: 2013
    ..Information obtained from these studies could be used to identify novel targets for therapeutic intervention in the treatment of osteoporosis, and may be used to identify individuals at risk for developing osteoporosis. ..
  19. Phosphorylation of PTH1R by TGF-betaRII in Bone Remodeling
    Tao Qiu; Fiscal Year: 2013
    ..This proposal may reveal a previously unrecognized function for T2RII in bone remodeling and a mechanism for PTH to regulate local growth factor at the level of membrane receptor. ..
  20. Mesenchymal Regulation of Osteogenesis
    Richard A Schneider; Fiscal Year: 2013
    ..The goal of this project is to identify genes and embryonic events that control bone formation. ..
  21. Bisphosphonates in the treatment of chronic kidney disease-mineral bone disease
    Sharon M Moe; Fiscal Year: 2013
    ..Both of these problems may be linked. The purpose of this study is to determine if a commonly used group of drugs, bisphosphonates, may help both bone and heart/blood vessel disease and determine the mechanism the drugs work. ..
  22. Role of Endothelial Progenitor Cells in vascular Aging and Calcification
    Amir Lerman; Fiscal Year: 2013
    ....
  23. MAP KINASE REGULATION OF OSTEOBLAST FUNCTION
    RENNY THEODORE FRANCESCHI; Fiscal Year: 2013
    ..This may have applications for diagnosis of osteoporosis and other bone disorders, such as osteoarthritis and certain cancers. ..
  24. Signaling in Inflammation, Stress, and Tumorigenesis
    GEORGE ROBERT STARK; Fiscal Year: 2013
    ..abstract_text> ..
  25. PTHrP/IHH Microenvironment Control for Growth Plate Tissue Engineering
    JUAN MANUEL TABOAS; Fiscal Year: 2013
    ..We will implant these constructs in dorsal subcutaneous pockets of immunodeficient mice and use histological and micro-CT assays to evaluate construct growth and GP-like structure maintenance. ..
  26. EBP50 Regulation of PTH Receptor in Bone
    Peter A Friedman; Fiscal Year: 2013
    ..The results will help define potential therapeutic targets for improved treatment of osteoporosis and other metabolic bone diseases. ..
  27. Regulation of Osteoblast Differentiation and Function by Connexin 43
    Joseph P Stains; Fiscal Year: 2013
    ..Indeed, understanding the coordination of osteoblast, osteocyte and osteoclasts networks is vital to the understanding nearly all diseases of skeletal metabolism. ..
  28. Hif-1 as an antagonist of load-induced bone formation
    Ryan C Riddle; Fiscal Year: 2013
    ..Clemens and Dr. Semenza and additional training in laboratory management, grantsmanship, and scientific presentation should ensure my success as an independent VA investigator. ..
  29. Injectable and Strong Nano-Apatite/Stem Cell Scaffolds for Bone Regeneration
    HUAKUN XU; Fiscal Year: 2013
    ..abstract_text> ..
  30. Aging and Diabetes-Related Factors Compromising Bone Fracture Resistance
    JEFFRY STEPHEN NYMAN; Fiscal Year: 2013
    ..The long-term goal is to identify the factors affecting the important determinants of fracture resistance and developing accurate diagnostic assessments of fracture risk. ..
  31. TSH RECEPTOR MULTIMERIZATION
    TERRY FRANCIS DAVIES; Fiscal Year: 2013
    ....
  32. Inhibition of bone formation by Prx1
    Mark S Nanes; Fiscal Year: 2013
    ..Understanding this mechanism will allow us to find new medications that stimulate new bone formation and regeneration of tissue in veterans who suffer from arthritis, aging, and menopause associated fractures. ..
  33. Interventions and Mechanisms of Disuse Osteopenia
    Daniel S Perrien; Fiscal Year: 2013
    ..These studies will determine whether Sirt1 and its substrates in osteoblasts and/or osteocytes are potential therapeutic targets for novel interventions for disuse osteopenia and, potentially, bone loss from a variety of other causes. ..
  34. Collagen Glycosylation, Maturation and Mineralization
    Mitsuo Yamauchi; Fiscal Year: 2013
    ..The proposed study should provide insights into the functions of glycosylation in collagen maturation and mineralization, thus, its involvement in bone formation and pathology, and its potential use for the assessment of bone quality. ..
  35. Elafin Therapy for Lung Diseases
    Marlene Rabinovitch; Fiscal Year: 2013
    ..The Administrative Core facilitates exchange of information and postdoctoral training in Lung Translational Medicine, and facilitates our strategy to move elafin into clinical trial in the next cycle. ..
  36. Interface Tissue Engineering for Soft Tissue-to-Bone Integration
    Helen H Lu; Fiscal Year: 2013
    ....
  37. The Role of Osteoactivin in Osteoblast Development and Function
    Fayez F Safadi; Fiscal Year: 2013
    ..abstract_text> ..
  38. Mitochondrial Dysfunction in Neurodegeneration of Aging
    Gary E Gibson; Fiscal Year: 2013
    ..Successful completion of the goals of these projects can be expected to provide new insights into neurodegenerative processes and contribute to novel approaches to ameliorating age-related neurodegenerations. ..
  39. The Cellular Basis of Heterotopic Ossification
    David J Goldhamer; Fiscal Year: 2013
    ....
  40. The Norepinephrine Transporter as a Novel Target for a Bone Anabolic Treatment
    Florent Elefteriou; Fiscal Year: 2013
    ..abstract_text> ..
  41. Noncollagenous Protein Interaction in Biomineralization
    Adele L Boskey; Fiscal Year: 2013
    ....
  42. Flow Perfusion Bioreactor Fabrication of Bioactive Polymer/ECM Hybrid Constructs
    Antonios G Mikos; Fiscal Year: 2013
    ....
  43. The contribution of T cells to the anabolic activity of PTH in bone
    Jau Yi Li; Fiscal Year: 2013
    ..This proposal may reveal a novel relevant role of T cells in the anabolic activity of PTH in bone. ..
  44. Brief Rest-Intervals Amplify the Response of Bone to Mechanical Loading
    Ted S Gross; Fiscal Year: 2013
    ..From a clinical perspective, success in this project would improve the potential to translate this concept into a non-invasive, non-pharmacologic intervention for bone loss pathologies. ..
  45. Modulated release of growth factors for stimulating progenitors in aging bone
    LIISA TIINA KUHN; Fiscal Year: 2013
    ....
  46. Syndecan-1 in Stromal Fibroblasts of Breast Carcinomas
    Andreas Friedl; Fiscal Year: 2013
    ..The knowledge generated with this work may lead to novel therapies that target the structure of this scaffold and prevent the escape of cancer cells. ..
  47. Glucocorticoids, Bone Strength and Angiogenesis
    ROBERT STEWART WEINSTEIN; Fiscal Year: 2013
    ..The proposed studies aimed at the mechanisms of the loss of bone strength in GIO should provide new insights that are sorely needed and immediately vital to veterans health care. ..