Building a death-defying islet beta cell Type I diabetes results when the cells that produce insulin (the islet beta cells) are killed by the immune system. The beta cell, like any other cell in the body, can be induced to die by activation of a process that leads to cell suicide. During this process, enzymes dismantle the structure of the cell and the remains are eaten by neighboring cells. In diabetes, the stimulus for beta cell suicide is provided by a number of agents most of which are made ....Building a death-defying islet beta cell Type I diabetes results when the cells that produce insulin (the islet beta cells) are killed by the immune system. The beta cell, like any other cell in the body, can be induced to die by activation of a process that leads to cell suicide. During this process, enzymes dismantle the structure of the cell and the remains are eaten by neighboring cells. In diabetes, the stimulus for beta cell suicide is provided by a number of agents most of which are made by the T cells of the immune system. Our aim is to interfere with this cell suicide process and engineer a beta cell that can resist T cell attack. Because genetically manipulated mice provide the flexibility we need to add and subtract genes from the beta cell we will use them as a model to build a death-defying beta cell. We will investigate three strategies. Firstly, cells will be engineered to express a molecule (CD30 ligand) which recognizes a protein on the surface of the attacking T cells and in so doing, sends a signal to the T cells to stop proliferating. Secondly, we will remove proteins (CD95, TNFRI) from the surface of the beta cell, that attacking T cells use to set in motion the cell suicide process. Thirdly, we will engineer beta cells that express inside themselves, cell death inhibitor proteins (Bcl-2, CrmA, p35) that can prevent the automatic process of cell suicide. It is our hope that studies with death-defying beta cells will find a new way to manipulate islet tissue for transplantation. In patients with diabetes, the beta cells have all been destroyed but the attacking T cells still remain. As a result, transplants of new beta cells are rapidly damaged. Beta cells that can resist ongoing immune attack may survive well enough to reverse the symptoms of diabetes. The success of this research could have an impact on a cure for diabetes.Read moreRead less
Role Of The Hypoxia-inducible Transcription Factor HIF-1a In Controlling Haematopoietic Stem Cell Fate
Funder
National Health and Medical Research Council
Funding Amount
$586,428.00
Summary
Haematopoietic stem cells (HSCs) reside in the bone marrow (BM) and make all immune and blood cells. We have found that, in the areas of the BM where HSC normally live, the level of oxygen is very low (hypoxia) and decreases even further when HSC are forced to move into the blood in order to be collected for transplantation. This project is to better understand how oxygenation of the BM controls HSC behaviour and properties, and to evaluate its impact on HSC transplantation.
Why Does Peripheral Airway Dysfunction Lead To Broncholitis Obliterans Syndrome In Lung Transplantation?
Funder
National Health and Medical Research Council
Funding Amount
$312,927.00
Summary
The uneven way that airways narrow (heterogeneity) is an important factor affecting the natural history, clinical expression and response to treatment in patients following lung transplantation. In the proposed study we plan to monitor the heterogeneity of the airways in patients immediately following lung transplantation and relate these changes to immunological markers of lung rejection.
Immunobiology Of Carbohydrate Antigens In Xenotransplantation
Funder
National Health and Medical Research Council
Funding Amount
$563,554.00
Summary
Xenotransplantation, the transplanting of organs from other species, is now seen as a viable solution to the problem of lack of supply of suitable human donors. The recent production of genetically engineered pigs represented a critical step towards clinical xenotransplantation. However, other sugars still remain that cause rejection. This project examines the consequences of these sugars.
Does Galalpha(1,3)Gal Still Play A Role In Xenograft Destruction After The Production Of Gal Knockout Pigs?
Funder
National Health and Medical Research Council
Funding Amount
$706,062.00
Summary
Advances in surgical and immunosuppressive techniques has led to organ transplantation as the method of choice for the treatment of many diseases. However, the number of suitable donors is dwindling, due to many factors, but largely as a result of the reduction in deaths from car accidents. Xenotransplantation, the transplanting of organs from species other than humans, is now seen as a viable solution to the world wide problem of lack of supply of suitable human donors. The pig is the most suit ....Advances in surgical and immunosuppressive techniques has led to organ transplantation as the method of choice for the treatment of many diseases. However, the number of suitable donors is dwindling, due to many factors, but largely as a result of the reduction in deaths from car accidents. Xenotransplantation, the transplanting of organs from species other than humans, is now seen as a viable solution to the world wide problem of lack of supply of suitable human donors. The pig is the most suitable for a variety of reasons. However, the problem is that all humans contain natural antibodies to the pig which would lead to rejection within a few minutes as the antibodies bind to the transplant and reverse its rapid destruction (so called hyperacute rejection). Recent studies from our laboratory have indicated that most, if not all, of the antibodies react with the sugar - galactose present on many molecules on the surface of transplanted pig tissues. Our studies have indicated very large amounts of this material present in pig blood vessels - guaranteeing the early rejection of transplanted organs such as kidney, heart and liver. The production of knockout pigs which do not express the galactose sugar is an important pre-requisite for successful xenotransplantation. Recently knockout pigs which lack an enzyme that makes this sugar have been produced, but not all the sugar was destroyed. We have recently described a second novel enzyme that also makes this sugar. We will examine a role of this enzyme in xenotransplantation. These studies will be the prelude to the production of pigs which could be used for human transplantation.Read moreRead less
NON IMMUNOLOGICAL BARRIERS TO SUCCESSFUL TREATMENT OF DIABETES BY XENOTRANSPLANTATION
Funder
National Health and Medical Research Council
Funding Amount
$310,500.00
Summary
Tragically patients whom suffer from diabetes mellitus develop major secondary complications such as renal failure, even with today's tight glucose control. Insulin injections minimise diabetic complications but restricts lifestyle and an alternative, pancreatic islet cell transplantation, is limited by donor shortage. With genetic technology, pig donor tissue is a feasible donor source. This project will use an inbred pig colony to assess long term pig fetal and neonatal islet cell function in ....Tragically patients whom suffer from diabetes mellitus develop major secondary complications such as renal failure, even with today's tight glucose control. Insulin injections minimise diabetic complications but restricts lifestyle and an alternative, pancreatic islet cell transplantation, is limited by donor shortage. With genetic technology, pig donor tissue is a feasible donor source. This project will use an inbred pig colony to assess long term pig fetal and neonatal islet cell function in combination with a kidney graft in the absence of an immune response. Using this specifically inbred pig colony we will carefully catalogue the type, number and distribution of endogenous retroviruses within pig genes. Using new and novel techniques we will develop a new strategy by which we can block and overcome this major concern of xenotransplantation. Ultimately a unique Australian resource will be developed which may provide unlimited islets for safe, large-scale transplantation of diabetics before they develop debilitating secondary complications from their diabetes and provide an alternative to the only current method of curing endstage renal failure with a combined pancreas and kidney transplant.Read moreRead less
Hormonal Resuscitation And P38 MAP Kinase Inhibition To Enhance Quality Of Cadaveric Donor Organs For Transplantation
Funder
National Health and Medical Research Council
Funding Amount
$469,500.00
Summary
The transplantation of organs such as the heart, lung, liver, kidney and pancreas from brain-dead donors is limited primarily by the shortage of donor organs. It is now recognised that as many as 25% (one in four) potentially usuable donor organs are lost after brain death due to the rapid deterioration that occurs in organs after brain death. There is evidence that this deterioration is due to loss of the normal hormones that are essential to the normal functioning of these organs. In this proj ....The transplantation of organs such as the heart, lung, liver, kidney and pancreas from brain-dead donors is limited primarily by the shortage of donor organs. It is now recognised that as many as 25% (one in four) potentially usuable donor organs are lost after brain death due to the rapid deterioration that occurs in organs after brain death. There is evidence that this deterioration is due to loss of the normal hormones that are essential to the normal functioning of these organs. In this project, we will use a pig model of brain death that we have extablished in our laboratory to examine the effects of hormone replacement on the function of organs that are used for transplantation. We will also test a novel drug aimed at protecting donor organs during the period between removal of the organ and transplantation. If successful, these treatments have the potential to markedly increase the numbers of organ transplants and to improve the outcomes for recipients of these transplants. In the Australian and New Zealand setting, a 25% increase in the number of donor organs would results in approximately 220 more people per year receiving these life-saving operations.Read moreRead less