This project is a biochemical investigation of collagen, which is the principle protein of bone, joints, blood vessels and skin. More than 200 mutations have been identified in the genes for type I collagen that result in Osteogenesis Imperfecta (OI), otherwise known as brittle-bone disease, in children and adults. However, very little is known about how these mutations cause bones to be brittle and why the disease varies so widely in severity. Our experiments are directed towards a better under ....This project is a biochemical investigation of collagen, which is the principle protein of bone, joints, blood vessels and skin. More than 200 mutations have been identified in the genes for type I collagen that result in Osteogenesis Imperfecta (OI), otherwise known as brittle-bone disease, in children and adults. However, very little is known about how these mutations cause bones to be brittle and why the disease varies so widely in severity. Our experiments are directed towards a better understanding of how bone cells respond to the mutant collagen and how these mutations actually result in brittle bones. We know that the majority of OI-causing mutations typically lead to a severe OI because the mutant collagen interferes with normal functioning of the matrix and effectively weakens it. We will examine how the mutant collagen disrupts normal cell function using bone and skin cell lines in which we have added a mutated collagen gene. The mutations we will introduce are the same ones that cause OI in patients. The experiments cannot be carried out with OI cell lines isolated from humans because it is very difficult to identify the mutant collagen in the matrix. Instead we have engineered a marker into the mutant collagen to allow the mutant collagen to be easily tracked. We will then examine how the presence of the mutant collagen affects matrix integrity, turnover and the formation of mutant matrix. In the second part of the study we will make a transgenic mouse that carries a specific collagen mutation. This will allow us to examine the fate of mutant collagen in a whole animal. As with the engineered cells described above, the mutant collagen will be altered to allow easy tracking. Collectively, these experiments will provide valuable information about how the presence mutant collagen disprupts integrity of the extracellular matrix of skin and bone.Read moreRead less
Role Of Neutrophil Proteases In The Mobilisation Of Haemopoietic Progenitor Cells
Funder
National Health and Medical Research Council
Funding Amount
$318,279.00
Summary
Mobilisation is a procedure consisting in inducing the egress of blood forming cells (haemopoietic stem cells) from the bone marrow, where they normally reside, into the blood. The most common agent to induce mobilisation of haemopoietic stem cell is a cytokine called granulocyte - colony stimulating factor (G-CSF). In recent years, the number of transplantations performed with mobilised blood stem cells has exceeded those performed with bone marrow. Elements contributing to this success have be ....Mobilisation is a procedure consisting in inducing the egress of blood forming cells (haemopoietic stem cells) from the bone marrow, where they normally reside, into the blood. The most common agent to induce mobilisation of haemopoietic stem cell is a cytokine called granulocyte - colony stimulating factor (G-CSF). In recent years, the number of transplantations performed with mobilised blood stem cells has exceeded those performed with bone marrow. Elements contributing to this success have been the simplicity of the procedure (daily injections of a mobilising cytokines such as G-CSF), a more rapid recovery following high dose chemotherapy and transplantation, and lower costs. Despite its common use in clinics, the molecular mechanisms responsible for haemopoietic stem mobilisation following injection of cytokines are still unknown. A large body of experimental data demonstrate the critical role of adhesive interactions between blood forming cells and the bone marrow microenvironment These interactions control the lodgement of blood forming cells in the bone marrow, where they normally reside, and their egress into the blood during mobilisation. Experiments from this laboratory have shown that the mobilisation of blood forming cells that follows the administration of G-CSF, may be the consequence of the accumulation in the bone marrow of a class of leukocytes called neutrophils. These neutrophils subsequently release within the bone marrow a set of enzymes that specifically cleave a cell adhesion molecule expressed in the bone marrow, and therefore disrupt the adhesive interactions between the bone marrow and the blood forming cells resulting in their egress in the blood. This proposal aims to demonstrate this hypothesis and to provide tools to predict and improve the levels of mobilisation that can be achieved with healthy donors and cancer patients.Read moreRead less
Role Of Neutrophil Proteases And Their Inhibitors In Haematopoietic Stem Cell Mobilisation
Funder
National Health and Medical Research Council
Funding Amount
$472,750.00
Summary
Mobilisation is the enforced migration of blood forming cells (haemopoietic stem cells) from the bone marrow, where they normally reside, into the blood. The most common agent used to induce mobilisation of haemopoietic stem cells is a cytokine called G-CSF. In recent years, the number of transplantations performed with mobilised blood stem cells has exceeded those performed with bone marrow aspirates. The simplicity of the procedure (daily injections of G-CSF, absence of bone marrow aspiration) ....Mobilisation is the enforced migration of blood forming cells (haemopoietic stem cells) from the bone marrow, where they normally reside, into the blood. The most common agent used to induce mobilisation of haemopoietic stem cells is a cytokine called G-CSF. In recent years, the number of transplantations performed with mobilised blood stem cells has exceeded those performed with bone marrow aspirates. The simplicity of the procedure (daily injections of G-CSF, absence of bone marrow aspiration), better patient recovery and survival, lower costs have all contributed to the success of this procedure. Despite its common use in clinics to rescue cancer patients undergoing high-dose chemotherapy, the reasons why haemopoietic stem cells mobilise are still not fully understood. It is known that haemopoietic stem cells stay in the bone marrow because they express 'adhesive' molecules on their surface. In pioneering work, this laboratory has shown that cytokines such as G-CSF increases the number of neutrophils (a type of white blood cell) in the bone marrow. These neutrophils release enzymes (known as proteases) which cut into pieces the 'adhesive' molecules and other proteins responsible for the retention of blood forming cells within the bone marrow. This project aims to further these investigations to include both the role of proteases and their naturally-occurring inhibitors in the mobilisation of blood forming cells. Particularly, we will investigate how the expression of serpins and TIMPs, two families of protease inhibitors, is regulated in the bone marrow during mobilisation and how these inhibitors control the activity of proteases responsible for the mobilisation of blood forming cells. This knowledge may lead to the design of new treatments that induce more efficient mobilisation and ultimately improve the success of haemopoietic stem cell transplantation.Read moreRead less
CD164: A Sialomucin Adhesion Molecule With Potent Growth Inhibitory Properties
Funder
National Health and Medical Research Council
Funding Amount
$242,545.00
Summary
Blood cell production in the adult mammal is normally restricted to the bone marrow. The ongoing production of blood cells is well regulated and dependent on the controlled proliferation and development of rare, multipotent precursors cells commonly termed stem cells. The blood forming stem cells exist in intimate contact with other cells and tissues that comprise the red bone marrow tissue. It is currently thought that stem cell localisation, survival and growth within the bone marrow is, in pa ....Blood cell production in the adult mammal is normally restricted to the bone marrow. The ongoing production of blood cells is well regulated and dependent on the controlled proliferation and development of rare, multipotent precursors cells commonly termed stem cells. The blood forming stem cells exist in intimate contact with other cells and tissues that comprise the red bone marrow tissue. It is currently thought that stem cell localisation, survival and growth within the bone marrow is, in part, regulated by specific interactions between the stem cells and neighbouring cells or the biochemical products of these cells. Stem cells use specific cell surface structures or cell adhesion molecules to mediate these important interactions. This project seeks to investigate the role in blood cell production, of a specific cell surface molecule, CD164, a member of a larger family of molecules with similar structural features thought to be involved in inhibition of cell growth. The main focus of the project is to identify a ligand or binding molecule for CD164. This information will allow an investigation of the consequences of binding between CD164 and its ligand by stem cells. It is proposed that the CD164-ligand interaction is one of a number of important inhibitory interactions used to regulate proliferation of stem cells. These studies will be greatly facilitated by the generation of a mouse lacking CD164.Read moreRead less