Bcl-2 Proteins And The Regulation Of The Megakaryocyte Lineage.
Funder
National Health and Medical Research Council
Funding Amount
$416,240.00
Summary
Platelets are tiny cells that circulate in the blood. They are essential for blood clotting. Too few platelets leads to uncontrolled bleeding. Platelets are produced in the bone marrow by cells called 'megakaryocytes'. Cancer chemotherapy often causes dangerous decreases in platelet count - this is thought to be because it kills megakaryocytes. We will pinpoint the molecules responsible for megakaryocyte life and death. This has the potential to make the side effects of chemotherapy less severe.
A New BTB-ZF Family Transcription Factor Required In Development And Dysregulated In Malignant Disease
Funder
National Health and Medical Research Council
Funding Amount
$439,813.00
Summary
We are studying the function and biology of a novel gene that looks like a generegulator. We generated a zebrafish mutant with defective myeloid development, and we found this gene causes the defect. This mutant fish provides a handle on the biological function of the gene in development. This gene has the hallmarks of a transcription factor and we will study how it regulates other genes, and how it may be a target for treatment of several cancers in which expression of this gene is activated.
LMO2-containing Complexes In Leukemia And Blood Cell Development
Funder
National Health and Medical Research Council
Funding Amount
$803,652.00
Summary
Childhood T-cell leukemias have a poor prognosis for recovery. We are determining, with atomic level precision, how the proteins Lmo2 (also linked to prostate and other cancers) and Tal1, and their binding partners contribute to both normal blood cell development and T-cell leukemia. With this information we are developing reagents that can be used to disrupt disease-causing complexes, and which will lead towards the development of new, specific, therapeutics for leukemias and other cancers.
While most leukemia patients initially respond well to chemotherapy, >60% die because the disease returns as a result of the survival of leukaemia cells following treatment. We have identified a new protein, osteopontin (OPN), that may allow the survival of leukaemia cells and therefore reduce the ability of chemotherapy to erradicate disease. We seek to examine the role of OPN in leukemia with a view toward developing targetted therapies in the future.
The Genetic Control Of Platelet Production And Function
Funder
National Health and Medical Research Council
Funding Amount
$558,920.00
Summary
Platelets are the tiny cells that circulate in the body and make blood clot. The human body has more than a trillion of them at any one time, and they are replaced every week by the blood producing cells that reside in the bone marrow. Keeping the normal number of platelets steady is incredibly important any significant drop can result in a life-threatening hemorrhage. The clinical name given to a low platelet count is thrombocytopenia, and it is a very common problem. It can be caused by geneti ....Platelets are the tiny cells that circulate in the body and make blood clot. The human body has more than a trillion of them at any one time, and they are replaced every week by the blood producing cells that reside in the bone marrow. Keeping the normal number of platelets steady is incredibly important any significant drop can result in a life-threatening hemorrhage. The clinical name given to a low platelet count is thrombocytopenia, and it is a very common problem. It can be caused by genetic mutations, viral infections, or by cancer treatments like chemotherapy. The only way to raise platelet numbers in a person with thrombocytopenia is a blood transfusion, which carries with it risks and potential side effects. While we understand quite a lot about how the body produces platelets, we don t know anywhere enough to be able to develop new treatments. Our work is focused on the identification of the genes that control the process, beginning with mouse models of thrombocytopenia, genome mapping, gene isolation, and finally, making the links between the newly identified genes and patients with thrombocytopenia. It will give us a much better understanding of how platelets are produced, how things go wrong in human disease, and how new therapies might be developed to treat them.Read moreRead less
Role Of Selectins And Their Receptors In The Regulation Of The Haemopoietic System
Funder
National Health and Medical Research Council
Funding Amount
$472,500.00
Summary
The production of blood cells occurs in the bone marrow. This process depends on the controlled proliferation and development of rare and multipotent precursors called haemopoietic stem cells, and involves a subtle balance between the positive regulation of proliferation and growth inhibition necessary to prevent blood cell overproduction and leukaemia. We have recently shown that two related proteins expressed at the surface of cells of the bone marrow vasculature negatively regulate blood cell ....The production of blood cells occurs in the bone marrow. This process depends on the controlled proliferation and development of rare and multipotent precursors called haemopoietic stem cells, and involves a subtle balance between the positive regulation of proliferation and growth inhibition necessary to prevent blood cell overproduction and leukaemia. We have recently shown that two related proteins expressed at the surface of cells of the bone marrow vasculature negatively regulate blood cell formation. These proteins, called P-selectin and E-selectin, are essential to regulate the migration of immune cells into lymphoid organs and inflamed tissues. We have found that these selectins also mediate the adhesion of haemopoietic stem cells in the bone marrow vasculature, inhibit their proliferation and kill some of their progeny. This project includes three specific aims to: 1) characterise the role of P-selectin and E-selectin in vivo in the regulation of blood cell formation, 2) understand the molecular mechanisms inside haemopoietic stem cells which are responsible for the growth inhibition and cell death in response to selectins, and 3) identify the receptors which are responsible for these effects of selectins on haematopoietic stem cells. These findings will give us a better understanding of how blood formation is regulated in vivo and how these interactions are perturbed during the emergence of leukaemia.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
Identification Of Genes Important In Myeloid And Haemopoietic Development By Genetic Screening In Zebrafish
Funder
National Health and Medical Research Council
Funding Amount
$425,250.00
Summary
Zebrafish have emerged as a powerful experimental model in developmental genetics. Their favourable attributes include their reproductive biology, the optical clarity of embryos, and the accessibility of embryos for experimental procedures. Previous studies overseas have recovered over 1500 strains of zebrafish with inherited diseases due to induced mutations in about 500 genes. Many of these zebrafish have abnormalities of unexpected precision and are leading to new genes with novel specialized ....Zebrafish have emerged as a powerful experimental model in developmental genetics. Their favourable attributes include their reproductive biology, the optical clarity of embryos, and the accessibility of embryos for experimental procedures. Previous studies overseas have recovered over 1500 strains of zebrafish with inherited diseases due to induced mutations in about 500 genes. Many of these zebrafish have abnormalities of unexpected precision and are leading to new genes with novel specialized functions. About 50 mutant zebrafish strains exist in which red blood cell development is perturbed - this was easily recognized because the transparency of embryos enabled lack of blood be easily seen. Our new studies aim primarily to recover mutant zebrafish with disorders of white blood cell formation. We have identified methods to recognize failure of white blood cell formation in zebrafish, and will employ these methods to look for inherited disorders that specifically affect white blood cell development in a process called genetic screening. Fish with different sets of randomly mutated genes will be systematically screened to identify those with abnormal white blood cell development. We have tested our approach and identified several mutants affecting white blood cell development. Once these new strains of fish are identified, we will find the genetic lesion responsible for the abnormality in several of the most interesting strains by gene mapping and positional cloning. Hence, the mutant zebrafish identified in the screen will eventually lead to the discovery of new genes important in white blood cell growth and development. The fish themselves will provide insights into the causes of congenital diseases of white blood cells. Since many genes involved in early development are also important in cancer, we believe that newly identified genes will also help understand the causes of abnormal growth of white blood cells in leukaemia.Read moreRead less