Cell-matrix interactions in bone biology: focus on the roles of integrin-linked kinase and rhoa in osteogenic cells

The overall objective of this PhD project is to assess the importance of direct osteogenic cell migration in vivo and gain mechanistic insight. The research hypothesis is that integrin-mediated cell-matrix interactions and regulation of RhoA activity likely play a central role in osteoprogenitors. We will therefore generated conditional knockout mice (cKO) of ILK and RhoA, two well-known mediators of cell motility, targeting early osteoblast lineage cells (OsxCre). The mice will be analyzed in depth and the translational significance is explored.DANKWOORD I SUMMARY V SAMENVATTING IX LIST OF ABBREVIATIONS XIII TABLE OF CONTENTS XIX 1 GENERAL INTRODUCTION 1 1.1 BONE FORMATION AND REMODELING 3 1.2 CELL-MATRIX INTERACTIONS AND ACTIN CYTOSKELETAL DYNAMICS 14 2 OBJECTIVES AND AIMS 23 2.1 GENERAL OBJECTIVES 25 2.2 SPECIFIC AIMS 25 3 ROLE OF INTEGRIN-LINKED KINASE IN OSTEOPROGENITORS AND BONE FORMATION 27 3.1 ABSTRACT 29 3.2 INTRODUCTION 29 3.3 MATERIALS AND METHODS 31 3.4 RESULTS 35 3.5 DISCUSSION 46 4 THE SMALL GTPASE RHOA INFLUENCES ACTIN DYNAMICS IN OSTEOGENIC CELLS AND REGULATES BONE FORMATION IN VIVO 53 4.1 ABSTRACT 55 4.2 INTRODUCTION 55 4.3 MATERIALS AND METHODS 56 4.4 RESULTS 61 4.5 DISCUSSION 75 5 THE ROLE OF RHOA IN ESTABLISHED OSTEO-ANABOLIC TREATMENTS IN VIVO 79 5.1 ABSTRACT 81 5.2 INTRODUCTION 81 5.3 MATERIALS AND METHODS 83 5.4 RESULTS 85 5.5 DISCUSSION 90 5.6 CONCLUSION 92 6 GENERAL DISCUSSION AND CONCLUSION 93 6.1 THE ROLE OF ILK IN OSTEOGENIC CELLS 95 6.2 THE ROLE OF RHOA IN OSTEOGENIC CELLS 96 6.3 THE ROLE OF RHOA IN ESTABLISHED OSTEO-ANABOLIC PATHWAYS IN VIVO 97 6.4 INTERACTIONS BETWEEN ILK AND RHOA IN OSTEOGENIC CELLS 98 6.5 CONCLUSION AND FUTURE PERSPECTIVES 99 7 REFERENCES 101 8 CURRICULUM VITAE 115nrpages: 145status: publishe