Investigation Of Pancreatic Insulin-secreting Cell Function And Survival
Funder
National Health and Medical Research Council
Funding Amount
$375,750.00
Summary
Diabetes remains a major health problem in Australia. Both type 1 and type 2 diabetes is eventually due to pancreatic insulin-producing beta-cell destruction, which is caused mainly by the cell death, so called 'apoptosis' or programmed suicide of the cells. Thus, attempting to protect beta-cells against death and rescue their insulin secretory function is emerging as a strategy for the treatment of diabetes. However, how the beta-cells undergo death and how to protect the cell death are still n ....Diabetes remains a major health problem in Australia. Both type 1 and type 2 diabetes is eventually due to pancreatic insulin-producing beta-cell destruction, which is caused mainly by the cell death, so called 'apoptosis' or programmed suicide of the cells. Thus, attempting to protect beta-cells against death and rescue their insulin secretory function is emerging as a strategy for the treatment of diabetes. However, how the beta-cells undergo death and how to protect the cell death are still not completely understood. We have recently discovered a new protein, named sphingosine kinase, that is a strong protector against cell death. We also found that this enzyme is involved in process of insulin secretion. Thus, this application seeks to establish a dual role of this enzyme in protecting beta-cells from death and promoting insulin secretion by the cells. This will ultimately allow us to create new therapeutic strategy to target this protein for the management of diabetes.Read moreRead less
Biochemical Basis Of Islet Beta-cell Compensation And Failure In Normal Pregnancy And Gestational Diabetes Mellitus
Funder
National Health and Medical Research Council
Funding Amount
$480,828.00
Summary
The factors causing the current world-wide crisis of rapidly rising diabetes prevalence remain poorly understood. Of potential major importance, however, is the hypothesis that abnormalities in the maternal metabolic environment, as occur in gestational diabetes (GDM) (diabetes that develops in pregnancy), result in abnormal development of metabolic systems in the baby resulting in higher risk of adult onset diabetes in the babies. Therefore, it is of importance to understand the mechanisms caus ....The factors causing the current world-wide crisis of rapidly rising diabetes prevalence remain poorly understood. Of potential major importance, however, is the hypothesis that abnormalities in the maternal metabolic environment, as occur in gestational diabetes (GDM) (diabetes that develops in pregnancy), result in abnormal development of metabolic systems in the baby resulting in higher risk of adult onset diabetes in the babies. Therefore, it is of importance to understand the mechanisms causing GDM, such that effective measures can be developed to counter this passing on of diabetes risk from mother to baby. It is known that a key factor causing GDM is failure of maternal pancreatic islet beta-cells to compensate for increased demands for insulin production in pregnancy. Poorly understood, however, are the cellular mechanisms of islet beta-cell compensation in normal pregnancy and failure of this compensation in GDM pregnancy. We have recently shown that there is a pathway of fat metabolism (triglyceride- free fatty acid cycle) within the islet beta-cell that has an important role in amplyfing insulin secretion necessary to maintain normal blood glucose and protecting the islets from failure in obese rats. The major focus of this project is to test the hypothesis that this pathway has a key role in the adaptation of pancreatic islets to normal pregnancy and its dysfunction contributes to the causation of GDM. Of great interest from preliminary findings is that a master regulator of glucose and fat metabolism, PGC1alpha, is markedly reduced in islets during normal pregnancy. Studies will also be directed to PGC1alpha's role in islet adaptation to pregnancy and failure in GDM. We expect that successful completion of this project will lead to the development of highly targeted counter measures to prevent GDM and to slow and reverse the current epidemic of diabetes.Read moreRead less
Ceramide Metabolism And ER Stress In Fatty-acid Mediated Destruction Of Pancreatic Beta Cells
Funder
National Health and Medical Research Council
Funding Amount
$549,092.00
Summary
The underlying cause of Type 2 diabetes is the failure of pancreatic beta cells to secrete sufficient insulin to overcome the insulin resistance that is associated with obesity. Beta cell failre is associated with both defective insulin secretion and loss of beta cell mass. This proposal focuses on the cellular mechanisms and stress pathways whereby too much fatty acid promotes beta cell death.
Mechanisms Of Fatty-acid Mediated Destruction Of Pancreatic Beta Cells
Funder
National Health and Medical Research Council
Funding Amount
$510,476.00
Summary
Type 2 diabetes is associated with obesity, but not all obese individuals develop the disease. Non-diabetic obese subjects are able to compensate for diminished sensitivity to insulin (a general feature of obesity) by enhanced output of insulin from the pancreatic beta-cells of the islet of Langerhans. In diabetics this compensatory mechanism is disrupted. Obesity and Type 2 diabetes are also associated with elevated levels of fatty acids (FAs) in the bloodstream. These can be taken up by the be ....Type 2 diabetes is associated with obesity, but not all obese individuals develop the disease. Non-diabetic obese subjects are able to compensate for diminished sensitivity to insulin (a general feature of obesity) by enhanced output of insulin from the pancreatic beta-cells of the islet of Langerhans. In diabetics this compensatory mechanism is disrupted. Obesity and Type 2 diabetes are also associated with elevated levels of fatty acids (FAs) in the bloodstream. These can be taken up by the beta-cells where they exert both short and long-term effects. In the longer term FAs can be toxic to beta-cells and this is thought to be important in the failure of beta-cell compensation. The project is aimed at a better understanding of the manner by which different types of FAs influence the susceptibility of beta-cells to destruction. It builds on our preliminary results suggesting that the capacity of the beta-cell to convert saturated FAs to unsaturated FAs helps protect them from destruction. Our aim is to examine the mechanisms underlying this protection.Read moreRead less
Pathophysiological Mechanisms In The Antiphospholipid Syndrome: B2GPI Regulation Of FXI-FXIa
Funder
National Health and Medical Research Council
Funding Amount
$530,591.00
Summary
The major protein that the antibodies in the antiphospholipid syndrome (APS) bind is called Beta 2-GPI. Antibodies to Beta 2-GPI are associated with recurrent miscarriage, intrauterine growth retardation, clots and stroke. Treatment of patients with the APS are treated with medication that has significant side effects. The development of more targeted and effective therapies for the APS requires a greater understanding of how the antibodies cause their effects, which is addressed in this study.
Diabetes mellitus is a disease reaching epidemic proprotions in the western world. Nearly one million Australians have diabetes mellitus; many of these people will suffer debilitating secondary complications, resulting in significant morbidity and mortality at considerable social and economic cost. Complications include heart attack, stroke, kidney disaease, blindness and limb amputation. There are two forms of diabetes (type I and type 2), and though there are considerable differences in their ....Diabetes mellitus is a disease reaching epidemic proprotions in the western world. Nearly one million Australians have diabetes mellitus; many of these people will suffer debilitating secondary complications, resulting in significant morbidity and mortality at considerable social and economic cost. Complications include heart attack, stroke, kidney disaease, blindness and limb amputation. There are two forms of diabetes (type I and type 2), and though there are considerable differences in their etiology, both forms result in an inability of the body to control blood sugar levels. Beta cells release the hormone insulin, which regulates blood sugar levels. Current knowledge suggests that a loss of beta cell mass is important for both diseases. For type I diabetes the beta cells are destroyed by the immune system. Though for type 2 diabetes the causes are less clear, it is apparent that the beta cells are dying. Our research is focused on understanding the molecular pathways that control beta cell survival and regulate their death. Such knowledge would help us understand the complex processes leading to the development of diabetes. Furthermore, we could use this knowledge in the design of genetic engineering strategies to create 'death-defying' beta cells, as a potential therapeutic strategy for the treatment of diabetes.Read moreRead less
Mechanisms Of PKCepsilon-dependent Regulation Of Beta-cell Lipid Metabolism And Insulin Secretion
Funder
National Health and Medical Research Council
Funding Amount
$555,892.00
Summary
Lipid loading of the insulin-producing beta cells of the pancreas contributes to the onset of Type 2 diabetes, but the mechanisms are poorly understood. We have recently established that inhibiting the enzyme PKCe helps restore insulin secretion. By better defining the cellular role of PKCe we will clarify how insulin secretion is disrupted by fatty acids and cholesterol.
The Role Of Gonadotropins In Regulating The Production Of Alzheimer's Beta Amyloid
Funder
National Health and Medical Research Council
Funding Amount
$400,278.00
Summary
Currently, about 160,000 Australians suffer from dementia; of which 50-70% are Alzheimer's disease (AD) cases. AD is characterised clinically by memory and personality changes and pathologically by deposition of amyloid. Of particular importance in the disease pathogenesis, is a small molecule called beta amyloid, of which the overproduction is thought to be central to the development of AD. Changes in the levels of the reproductive hormones, particularly low levels of oestrogen during menopause ....Currently, about 160,000 Australians suffer from dementia; of which 50-70% are Alzheimer's disease (AD) cases. AD is characterised clinically by memory and personality changes and pathologically by deposition of amyloid. Of particular importance in the disease pathogenesis, is a small molecule called beta amyloid, of which the overproduction is thought to be central to the development of AD. Changes in the levels of the reproductive hormones, particularly low levels of oestrogen during menopause or testosterone during andropuase, has been associated with the increased risk of developing AD and in altering the levels of beta amyloid. Furthermore, menopause and andropause are also characterised by changes in other reproductive hormones such as the gonadotropins. High levels of the gonadotropins have also been associated with the increased risk of developing AD. Therefore it is important to identify how these changes modify the risk of developing AD. This study examines the role of the gonadotropins in regulating beta amyloid levels in cell culture and in an animal model for AD. Furthermore, this study will assess, in the animal model, the use of gonadotropin lowering agents to reduce levels of beta amyloid. The results from this study will provide important data on how reproductive hormones regulate beta amyloid. Further insight into these mechanisms will provide therapeutic or preventative strategies for AD.Read moreRead less