The Role Of P62/A170 In Pathological Bone Destruction
Funder
National Health and Medical Research Council
Funding Amount
$276,000.00
Summary
Approximately up to 30% of patients are admitted to public hospitals in Australia for reasons related to skeletal disorders, including trauma, osteoarthritis, osteoporosis, primary and secondary bone tumours, genetic and metabolic disorders. Abnormal bone resorption contributes to most of these diseases and conditions. Based on the clinical evidence of P62 mutation in patients with Paget's Disease of bone and our observation of the involvement of P62 in RANKL-induced NF-Kb signaling, we propose ....Approximately up to 30% of patients are admitted to public hospitals in Australia for reasons related to skeletal disorders, including trauma, osteoarthritis, osteoporosis, primary and secondary bone tumours, genetic and metabolic disorders. Abnormal bone resorption contributes to most of these diseases and conditions. Based on the clinical evidence of P62 mutation in patients with Paget's Disease of bone and our observation of the involvement of P62 in RANKL-induced NF-Kb signaling, we propose that intracellular molecule P62-A172 may play an important part in the switch off-on signals necessary for bone resorbing cells to resorb bone. To this end, we will study the molecular mechanism of P62 in action, and the interaction with its possible partners for the facilitation of abnormal bone resorption. The clinical significance of this project is to: 1) enhance understanding of abnormal bone resorption in Orthopaedic related diseases and conditions. 2) provide a strategy of drug development for the treatment of these disease and conditions.Read moreRead less
Molecular Determinants Of Bone Remodelling In The Bone Microenvironment
Funder
National Health and Medical Research Council
Funding Amount
$317,640.00
Summary
There is little information regarding the expression of specific molecules in human bone tissue or their role in skeletal disease. The process of bone remodelling is fundamental for the maintenance of skeletal integrity. Our understanding of the molecular signalling involved in activating bone remodelling is principally derived from tissue culture and animal experiments. We will study human cancellous bone samples donated by patients undergoing surgery, and with the consent of the next-of-kin, t ....There is little information regarding the expression of specific molecules in human bone tissue or their role in skeletal disease. The process of bone remodelling is fundamental for the maintenance of skeletal integrity. Our understanding of the molecular signalling involved in activating bone remodelling is principally derived from tissue culture and animal experiments. We will study human cancellous bone samples donated by patients undergoing surgery, and with the consent of the next-of-kin, taken at autopsy. These molecular and histomorphometric studies will determine whether the understanding derived from tissue culture and animal experiments is consistent with associations demonstrable in the human cancellous bone microenvironment. The elucidation of the molecular signalling in the human bone microenvironment is essential for the effective diagnosis and treatment of bone disease. Recently reported studies have shown very persuasively that fatigue microdamage accumulates in the skeleton and is targeted for repair by remodelling. Our preliminary data shows that microcrack length is positively correlated with IL-11 mRNA gene expression. We will further investigate mRNA gene expression of a number of cytokines involved in bone cell signalling and their association with the level of microdamage in the bone. Using a animal model of controlled bone microdamage induction we will seek to determine the bone remodelling causal relationship between microdamage and cytokine signalling. Furthermore, the cellular and molecular mechanisms that lead to trabecular structures are not well understood. These studies will provide new insight into the processes that determine trabecular structures. This project will investigate these mechanisms and increase our understanding of bone cell function, essential for diagnosis and design of rational treatment for bone diseases.Read moreRead less
Intrinsic Bone Qualities In Fragility Fracture Patients: Mass, Microarchitecture, Mineralization And Damage Accumulation
Funder
National Health and Medical Research Council
Funding Amount
$447,027.00
Summary
Osteoporosis drug therapies have been associated with a significant reduction in fragility fracture. Patients receiving osteoporosis drugs, which have different effects on BMD, may have similar reductions in fractures. Furthermore, patients with fragility fractures may have abnormalities in bone structural and material properties. Changes to the process of bone renewal, due to drug therapy, may explain why fracture risk decreases where no detectable change to the structure of bone has been detec ....Osteoporosis drug therapies have been associated with a significant reduction in fragility fracture. Patients receiving osteoporosis drugs, which have different effects on BMD, may have similar reductions in fractures. Furthermore, patients with fragility fractures may have abnormalities in bone structural and material properties. Changes to the process of bone renewal, due to drug therapy, may explain why fracture risk decreases where no detectable change to the structure of bone has been detected. It has also been shown that when bone renewal is suppressed microdamage accumulates in bone tissue, leading to reduced bone toughness. The toughness of bone is of primary importance in relation to fragility fractures, and it has been shown that the fatigue strength and fracture toughness (work to fracture) reduce considerably with age. This proposed study would seek to elucidate the role of bone tissue-level properties in determining bone quality for human subjects: patients with fragility hip fractures on no osteoporosis drugs therapy, hip fracture patients on osteoporosis drugs therapies, and normal age- and sex-matched individuals. Our laboratory has extensive experience in the analysis of the structure of human bone tissue. Recently, we have developed novel and unique techniques to assess bone quality, using micro-CT, backscatter SEM imaging, confocal microscopy and immunohistochemistry. This multifaceted study will identify at the bone tissue-level the structural mechanisms (micro-architecture, mineralisation, and microscopic cracking) that are indicative of the efficacy of fragility fracture drugs. Better understanding of the mechanisms by which bones are less likely to fracture will enable better targeting of osteoporosis drug therapy to individuals at risk of fragility fracture.Read moreRead less
Structural And Functional Analyses Of Rat Receptor Activator Of NF-kb Ligand
Funder
National Health and Medical Research Council
Funding Amount
$226,320.00
Summary
Rat RANKL (Xu and Zheng, rat RANKL, AustraliaProvisional Patent PQ3147) has a variety of biological activities including osteoclast differentiation and polarization, and dendritic cell function. Overproduction or increased activity of RANKL can result in excessive osteoclast formation, activation, and bone resorption. This process contributes to many common bone lytic disorders such as osteoporosis, Paget's disease, bone metastatic diseases, arthritis, aseptic bone loosening and non-union of fra ....Rat RANKL (Xu and Zheng, rat RANKL, AustraliaProvisional Patent PQ3147) has a variety of biological activities including osteoclast differentiation and polarization, and dendritic cell function. Overproduction or increased activity of RANKL can result in excessive osteoclast formation, activation, and bone resorption. This process contributes to many common bone lytic disorders such as osteoporosis, Paget's disease, bone metastatic diseases, arthritis, aseptic bone loosening and non-union of fractures. This proposal addresses the important and fundamental issue of RANKL regarding the role of molecular structure on its biological function. We have established that the TNF-like core domain is the functional domain, important for osteoclastogenesis, osteoclast polarisation and protecting against Fas-triggered apoptosis. This proposal will further characterise the mutant forms of the TNF-like core domain of RANKL using site directed mutagenesis and protein truncation analysis, and assess their respective binding activities to OPG and RANK, and their biological activities both in vitro and in vivo. It will lead us into better understanding of the structure-function relationship of RANKL. Ideally, we would like to develop a relative agent for the suppression of osteolysis in orthopaedic related diseases including osteoporosis. Such an optimized molecule could become a potent therapeutic agent that selectively inhibits osteoclast formation and bone resorption.Read moreRead less
Paget's Disease Of Bone Associated Sequestosome 1/p62 Mutations In Autophagy-mediated Processes And Bone Resorption
Funder
National Health and Medical Research Council
Funding Amount
$474,892.00
Summary
Paget’s disease of bone (PDB) is a common, chronic bone disorder characterized by focal lesions of increased bone degradation initiated by giant overactive osteoclasts. Subsequent bone formation is irregular, resulting in bones that are structurally weak. Genetic mutations are a common cause of PDB in Caucasians. Understanding the genetic mutations and their regulation on bone cells may lead to the discovery of a new drug target for the treatment of PDB.
The Role Of V-ATPase Accessory Subunit Ac45 In Osteoclasts
Funder
National Health and Medical Research Council
Funding Amount
$235,500.00
Summary
Osteoclasts are directly related to many lytic bone disorders including osteoporosis, osteoarthritis and Paget's diseases. Development of strategies to control the formation or activities of osteoclasts has been a major focus of bone research. The vacuolar proton pump (V-ATPase) located on the plasma membrane of the osteoclast is responsible for creating a low pH environment critical for bone resorption, and therefore a potential molecular target for the discovery of novel bone antiresorptive ag ....Osteoclasts are directly related to many lytic bone disorders including osteoporosis, osteoarthritis and Paget's diseases. Development of strategies to control the formation or activities of osteoclasts has been a major focus of bone research. The vacuolar proton pump (V-ATPase) located on the plasma membrane of the osteoclast is responsible for creating a low pH environment critical for bone resorption, and therefore a potential molecular target for the discovery of novel bone antiresorptive agents useful for the treatment of lytic bone disorders. The proposed research will give considerable insight into the role of the both V-ATPase accessory subunit Ac45 and V-ATPase complex in osteoclasts. Understanding the molecular and cellular mechanisms by which V-ATPases regulate osteoclast bone resorption will facilitate the development of novel and selective inhibitors for the treatment of lytic bone disorders.Read moreRead less
Osteal Macrophages: Novel Regulators Of Osteoblast Function And The Endosteal Stem Cell Niche
Funder
National Health and Medical Research Council
Funding Amount
$406,125.00
Summary
Bone diseases are a major health problem and current treatments are inadequate. We are investigating a novel role for macrophages (cells important in tissue maintenance and immune responses) in bone growth, repair and disease. Greater understanding of this will provide new ways to treat bone disease. We will also determine if these macrophages help support stem cells that reside near bone surfaces, which may provide new treatment strategies to improve bone marrow transplantation in cancer.
The Role Of TWIST Family Basic Helix-Loop-Helix Transcription Factors In Bone Cell Commitment, Function And Repair
Funder
National Health and Medical Research Council
Funding Amount
$485,928.00
Summary
In developed countries, projected estimates predict an alarming trend of a two to three fold increase in the number of fractures that require surgical intervention and rehabilitation therapy in the coming decades as a consequence of an aging population. Fracture healing is a complex physiological process that involves the coordinated participation of different bone marrow cells, immune cells and skeletal progenitor cells. Multiple factors regulate interactions between these cell types that influ ....In developed countries, projected estimates predict an alarming trend of a two to three fold increase in the number of fractures that require surgical intervention and rehabilitation therapy in the coming decades as a consequence of an aging population. Fracture healing is a complex physiological process that involves the coordinated participation of different bone marrow cells, immune cells and skeletal progenitor cells. Multiple factors regulate interactions between these cell types that influence the capacity of bone cell progenitors to develop into functional bone forming cells known as osteoblasts. An understanding of the fracture healing is critical for the future advancement of fracture treatment, and for identifying the mechanisms of skeletal growth and repair as well as the causes of aging and disease. This proposal seeks to identify critical regulatory molecules that act to mediate bone cell progenitor recruitment and development during bone fracture repair.Read moreRead less
Osteocytes (OY) are the most abundant cell type in bone whose high density and viability are essential for healthy bone. We have found that vitamin K, vitamin D and strontium, promote human OY differentiation. We will test these in novel models of human OY differentiation and survival, and in animal models of bone loss associated with vitamin D deficiency, menopause and glucocorticoid treatment. Our work will lead to a better understanding of human OY and give a new approach to treat osteoporosi ....Osteocytes (OY) are the most abundant cell type in bone whose high density and viability are essential for healthy bone. We have found that vitamin K, vitamin D and strontium, promote human OY differentiation. We will test these in novel models of human OY differentiation and survival, and in animal models of bone loss associated with vitamin D deficiency, menopause and glucocorticoid treatment. Our work will lead to a better understanding of human OY and give a new approach to treat osteoporosis.Read moreRead less