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
Identifying The Mechanisms By Which Ascorbate Stimulates Cellular Iron Uptake From Transferrin.
Funder
National Health and Medical Research Council
Funding Amount
$302,123.00
Summary
Vitamin C (ascorbate)-deficiency leads to anaemia and other symptoms of scurvy. Iron supplementation cannot alone correct this anaemia, with ascorbate being crucial. Almost all iron in plasma is bound to transferrin, and I have recent data showing that ascorbate stimulates transferrin-iron uptake. This research will identify how this stimulation occurs. This work has important biomedical implications for understanding iron uptake and anaemia, which affects 500 million people globally.
Age-related mechanisms of amino acid signalling in skeletal muscle. This project aims to increase our understanding of the role of glycine receptor-mediated signalling and its metabolism in the amino acid sensing capacity of mTORC1, a key enzyme regulating muscle protein synthesis. Ageing is associated with a progressive decline in skeletal muscle mass, weakness, and impaired regeneration after injury. Impaired anabolic signalling after food intake has been proposed as a key contributor, yet the ....Age-related mechanisms of amino acid signalling in skeletal muscle. This project aims to increase our understanding of the role of glycine receptor-mediated signalling and its metabolism in the amino acid sensing capacity of mTORC1, a key enzyme regulating muscle protein synthesis. Ageing is associated with a progressive decline in skeletal muscle mass, weakness, and impaired regeneration after injury. Impaired anabolic signalling after food intake has been proposed as a key contributor, yet the metabolic pathways responsible for nutrient sensing and regulation of protein synthesis remain unresolved. The project will assess defective amino acid sensing and protein synthesis in old mammals, identifying the role of glycine signalling in these processes. The project expects to underpin development of muscle-specific modulators of muscle homeostasis with broad relevance to Australia’s ageing population.Read moreRead less
Control Of Anabolic And Catabolic Pathways By AMPK
Funder
National Health and Medical Research Council
Funding Amount
$946,402.00
Summary
This project focuses on the role of the metabolic stress-sensing enzyme AMP-activated protein kinase (AMPK) in the control of glucose and fat metabolism. AMPK has been linked to the regulation of exercise capacity, longevity and the control of insulin sensitivity. This is important for our understanding of the metabolic dimensions of our Nations most important health problems including, type-2 diabetes, cardiovascular disease, obesity, neurodegeneration as well as other age onset diseases.
Manipulation Of Energy Metabolism To Control Lipid Accumulation And Insulin Action.
Funder
National Health and Medical Research Council
Funding Amount
$804,106.00
Summary
I am a metabolic biochemist investigating how overconsumption of calories, particularly fat, results in dysfunctional energy metabolism and increased the risk of type 2 diabetes. I examine changes in the daily rhythms of energy intake, energy utilisation and energy storage in different tissues of dietary and genetically modified animals to pinpoint novel ways of reducing fat accumulation and reducing the risk of type 2 diabetes.
NMR Of Red Cells: Plasma Membrane Oxidoreductase, And Cation Transport
Funder
National Health and Medical Research Council
Funding Amount
$192,388.00
Summary
An interesting paradox exists with respect to the 'central' function of the red blood cell (RBC): it delivers the main oxidising capacity to the body (O2), but it also carries the chemically opposite functionality in its membrane, namely reducing capacity. The reduction of many oxidised proteins and metabolites in blood plasma is mediated by a plasma-membrane oxido-reductase (PMOR). Ascorbic acid (vitamin C) dramatically accelerates this rate of reduction but its precise molecular role is unknow ....An interesting paradox exists with respect to the 'central' function of the red blood cell (RBC): it delivers the main oxidising capacity to the body (O2), but it also carries the chemically opposite functionality in its membrane, namely reducing capacity. The reduction of many oxidised proteins and metabolites in blood plasma is mediated by a plasma-membrane oxido-reductase (PMOR). Ascorbic acid (vitamin C) dramatically accelerates this rate of reduction but its precise molecular role is unknown; neither is the immediate source of the reducing equivalents (electrons) known. Novel, non-invasive, 13C NMR methods have been developed, and others are planned in this project, to study the rate of reduction of Otest? compounds, including 13C-ferricyanide, and reactions of 13C-ascorbate. This will provide a quantitative understanding of the kinetics of the redox reactions in the intact cell. The transfer of negative charges (electrons) from the cell, in the longer term (minutes) inevitably must be matched by the movement of cations (positive charges). The main cation flux is mediated by Na+, K+-ATPase, but various cation exchange pathways are also involved in the total Oionic economy? of the cell. Of special interest will be the calcium-activated K+ (or Gardos) channel. This Oopens? inappropriately in malaria, sickle cell anaemia, and under blood bank storage conditions, and this is thought to be the basis of some of the pathological events in these conditions. The alkali-metal cation exchange pathway ( Na+-Li+) is more activate in the red cells of many patients with hypertension. So, multiple-quantum NMR methods will be used to monitor membrane transport and binding of cations to characterise the kinetics and regulation of the K+-channel, and the Na+-Li+ exchange reactions. The significance will lie in a basic understanding of, and possible 'diagnostic methods' for the biochemical processes that occur in red blood cells in health and disease.Read moreRead less