Identification And Characterisation Of A Gene Causing Insulin Hypersecretion In A Mouse Model Of Diabetes Susceptibility
Funder
National Health and Medical Research Council
Funding Amount
$430,320.00
Summary
Diabetes is a disorder primarily characterised by the inability to produce and secrete the pancreatic hormone insulin, which regulates plasma sugar levels. This results in increased sugar levels which cause diabetic complications such as retinopathy and nephropathy. The inability to produce and secrete insulin is due to both defects in function as well as a reduction in pancreatic beta cells. Paradoxically it has been shown that some patients who are at risk of develping diabetes actually secret ....Diabetes is a disorder primarily characterised by the inability to produce and secrete the pancreatic hormone insulin, which regulates plasma sugar levels. This results in increased sugar levels which cause diabetic complications such as retinopathy and nephropathy. The inability to produce and secrete insulin is due to both defects in function as well as a reduction in pancreatic beta cells. Paradoxically it has been shown that some patients who are at risk of develping diabetes actually secrete more insulin than normal. Furthermore it has been suggested that this increase in insulin secretion actually may be associated with the decreased production and secretion of insulin characteristic of diabetes. The DBA-2 mouse is a model of reduced insulin production and secretion when exposed to high sugar levels or diabetes. However we have shown that in the normal non-stressed state DBA-2 mice actually secrete more insulin than normal and that this occurs from a very early age, suggesting that this trait is inherited. We have subsequently performed genetic studies and have identified a segment of DNA containing 10 genes associated with increased insulin secretion in DBA-2 mice. The level of one of these genes we have called Hip1 is increased 5-fold in DBA-2 mice, providing a candidate gene for increased insulin secretion in this model of diabetes susceptibility. However, whether Hip1 is also responsible for reduced insulin production and secretion in the DBA-2 mouse is not known. Therefore the overall hypothesis of this project is that the gene Hip1 which is associated with increased insulin secretion is also responsible for reduced insulin production and secretion when DBA-2 mice are exposed to high sugar or obesity. Determining why Hip1 is increased and whether it results in diabetes in DBA-2 mice may provide a reasonable candidate for the development of therapeutic interventions which may prevent the progression of diabetes in some patients.Read moreRead less
Targeting Nicotinamide Adenine Dinucleotide Biosynthesis To Improve Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$844,596.00
Summary
Nicotinamide adenine dinucleotide (NAD) is a cellular metabolite that regulates many biological processes. NAD levels decline with age and also in obesity and interventions that increase NAD levels produce favourable metabolic effects. In this proposal we will utilise a range of novel experimental models to define the molecular pathways that mediate the beneficial effects of NAD.
Thalassaemia is the most common blood disorder worldwide. In severe cases, life-long blood transfusions are needed to survive but complications including iron overload and bone disease can occur. Deferasirox, a drug used to treat iron overload has been linked to kidney stones and bone loss in these patients through increased loss of calcium in the urine. The purpose of this study is to investigate whether bone loss can be reversed by using a diuretic or an alternative iron chelator.
Understanding Sphingolipid Mediators Of Insulin Resistance
Funder
National Health and Medical Research Council
Funding Amount
$643,447.00
Summary
Sphingolipids are a class of lipid metabolites that have a variety of functions within cells. It has been known for some time that an accumulation of excess lipid, including certain sphingolipids, can adversely impact insulin action and glucose metabolism in cells. In this project we will a combination of strategies to test the hypothesis that the sphingolipid profile can be manipulated to have favourable effects on metabolism.
Targeting Insulin Hypersecretion To Prevent Type 1 And Type 2 Diabetes
Funder
National Health and Medical Research Council
Funding Amount
$834,596.00
Summary
Diabetes develops when islet beta-cells fail to secrete insulin. While major differences exist in the mechanisms by which type 1 and type 2 diabetes develop, there is overlap in beta-cell susceptibility factors. We will investigate whether an islet 'overwork' response to excess nutrient loads underlies beta-cell susceptibility to failure in both types of diabetes. We will also develop novel pharmacological approaches to reduce islet 'overwork' to prevent and treat type 1 and 2 diabetes.