Role Of Impaired Insulin Signalling In Fatty Acid-induced Muscle Insulin Resistance In Vivo
Funder
National Health and Medical Research Council
Funding Amount
$481,500.00
Summary
Type 2 diabetes represents an escalating global health problem. In Australia 7.5% of the population has diabetes and another 16% insulin resistance (impaired action of insulin in tissues). As well as diabetes, insulin resistance is closely associated with obesity, dyslipidaemia, hypertension and cardiovascular diseases (Syndrome X). While genetic factors play a role, a high caloric intake (particularly with a high fat content) and a sedentary lifestyle are extremely important environmental contr ....Type 2 diabetes represents an escalating global health problem. In Australia 7.5% of the population has diabetes and another 16% insulin resistance (impaired action of insulin in tissues). As well as diabetes, insulin resistance is closely associated with obesity, dyslipidaemia, hypertension and cardiovascular diseases (Syndrome X). While genetic factors play a role, a high caloric intake (particularly with a high fat content) and a sedentary lifestyle are extremely important environmental contributors to Syndrome X and diabetes. From evidence that we and others have obtained over the last few years it is now evident that an important mediator of insulin resistance is the quantity of fat molecules which accumulate in muscle and liver. This project examines mechanisms whereby this fat accumulation can disrupt the signalling mechanism normally causing increased glucose metabolism in response to insulin. While basic experiments in cell systems have identified some candidates, a need exists to demonstrate whether they actually cause the insulin resistance in the whole animal or human, or are merely associated with it. We will combine metabolic-physiological studies with a novel technique we have recently established in our laboratory for introducing DNA into skeletal muscle of laboratory animal models. We now aim to exploit this approach to obtain more definitive data about the importance of insulin signalling changes to insulin resistance. Two major steps in insulin signalling will be investigated, involving the insulin receptor substrate proteins and the kinase Akt-PKB, both strongly implicated in lipid-induced insulin resistance. This knowledge will be invaluable in improving strategies to lessen or prevent lipid-associated insulin resistance, a major contributor to the metabolic derangement in Type 2 diabetes and Syndrome X.Read moreRead less
The Pathogenesis Of Motor Neuron Degeneration Caused By A Triplet Repeat Expansion In The Androgen Receptor Gene.
Funder
National Health and Medical Research Council
Funding Amount
$284,748.00
Summary
Male sex hormones, or androgens, work by binding to a specific receptor, known as the androgen receptor. Androgens have an important and yet poorly understood role in nerve function. Our research is investigating how a genetic mutation in the androgen receptor causes Kennedy?s disease. This is a rare disease, affecting adult males, which causes nerves to die. The nerves which are affected are those supplying our muscles, called motor neurons. This leads to muscle wasting in the face and body. Ot ....Male sex hormones, or androgens, work by binding to a specific receptor, known as the androgen receptor. Androgens have an important and yet poorly understood role in nerve function. Our research is investigating how a genetic mutation in the androgen receptor causes Kennedy?s disease. This is a rare disease, affecting adult males, which causes nerves to die. The nerves which are affected are those supplying our muscles, called motor neurons. This leads to muscle wasting in the face and body. Other symptoms include testicular wasting, reduced fertility and breast tissue enlargement. It is currently not known what causes motor nerves to degenerate in Kennedy?s disease. We are endeavouring to investigate the cause of Kennedy?s disease via the generation of a transgenic mouse carrying this mutation. It is only through a studying transgenic mouse affected by this disease can we begin to understand what is happening to nerves to cause them to die, and importantly, how can we prevent them from dying. These studies will also provide crucial information on the effects of sex hormones on nerves. As there is currently no treatment for Kennedy?s disease, an aim of this project is to investigate how we can treat this disease. This will be the first time that we can systemically test potential treatments and work toward preventing the degeneration of these nerves. Kennedy?s disease is related to a number of other neurodegenerative diseases including Huntington?s disease, which are caused by similar genetic mutations. All of these diseases are caused by degeneration of specific nerve cells. Evidence suggests that there may be similar mechanisms involved in all of these diseases. The results of this study will therefore help us to understand a range of diseases and may eventually lead to the development of therapeutic strategies to prevent their debilitating effects.Read moreRead less