Diet-induced obesity is the foremost health concern in today�s society and causes many metabolic problems that lead to type diabetes and cardiovascular disease. This grant identifies ghrelin resistance, as a novel metabolic adaptation during obesity. Ghrelin is a hormone that normally stimulates food intake and body weight gain, however during obesity ghrelin does not stimulate food intake. Artificial induction of ghrelin resistance will restrict the development of diet _induced obesity.
Role Of Pacemaker Cells In The Generation Of Slow Wave Activity In The Prostate Gland
Funder
National Health and Medical Research Council
Funding Amount
$231,500.00
Summary
The prostate gland commonly enlarges in ageing males resulting in a condition known as benign prostatic hyperplasia which is poorly understood. Because of the strategic position of the prostate, its enlargement physically compresses the segment of the urinary system passing through it causing inconvenient and distressing symptoms, such as difficulty and hesitancy in urination, which often require surgical or medical intervention. Indeed patients diagnosed with benign prostatic hyperplasia are of ....The prostate gland commonly enlarges in ageing males resulting in a condition known as benign prostatic hyperplasia which is poorly understood. Because of the strategic position of the prostate, its enlargement physically compresses the segment of the urinary system passing through it causing inconvenient and distressing symptoms, such as difficulty and hesitancy in urination, which often require surgical or medical intervention. Indeed patients diagnosed with benign prostatic hyperplasia are often treated with pharmacological agents that reduce the size of the prostate or relax the prostate and bladder, thus relieving some of the symptoms. However, the precise cellualr mechanisms by which many of these drugs mediate their effects have not been confirmed. Moreover, although previous studies of the prostate gland have clearly established many of the basic properties of the tissue, there is currently a lack of information regarding the prostate gland at a cellular level. We have recently identified a specialised group of 'interstitial cells' in the prostate gland, which resemble the well-described 'interstitial cells of Cajal' in the gut. In the gut, these cells perform a wide variety of functions including the initiation of contractile activity. Interstitial cells are also thought to play a role in diseases of the bowel. This project aims to investigate the role of the interstitial cells in the functioning of the prostate gland. In addition, the effects of age and hormones on the interstitial cells will be considered, which may lead to a better understanding of conditions such as benign prostatic hyperplasia. Finally, identifying nerve-released substances that may affect the activity of these cells may also help identify alternative targets for treatment of benign prostatic hyperplasia.Read moreRead less
Secretion is an essential step in memory and learning, control of metabolism and reproduction and the functioning of most organs. Secretory dysfunction also underlies many diseases including type 2 diabetes. We plan experiments to test for a new model of control of insulin secretion.
Adrenergic Activation Of Brown Adipose Tissue In Humans.
Funder
National Health and Medical Research Council
Funding Amount
$323,301.00
Summary
Obesity is a major health and financial threat to society in the near future, thus new anti-obesity therapies are essential. Activation of brown adipose tissue (BAT) can increase resting energy expenditure by 20%, and its recent conclusive identification in adults renewed interest in its potential as an anti-obesity target. We will determine whether BAT can be activated pharmacologically in humans, whether obesity reduces its activity and if long-term drug treatment can increase BAT function.
Early Events In Arteriolar Remodeling: Adaptation To Prolonged Vasoconstriction
Funder
National Health and Medical Research Council
Funding Amount
$415,750.00
Summary
Small arteries, while acutely responding to their environment with changes in diameter to regulate local blood flow and pressure, also undergo structural adaptation or remodelling. These events occur over a range of time-frames and involve both non-genetically and genetically regulated events. Thus a contractile event, while initially decreasing vessel diameter, also activates longer time frame processes which can span from rearrangment of cellular junctions-contacts to overt structural changes ....Small arteries, while acutely responding to their environment with changes in diameter to regulate local blood flow and pressure, also undergo structural adaptation or remodelling. These events occur over a range of time-frames and involve both non-genetically and genetically regulated events. Thus a contractile event, while initially decreasing vessel diameter, also activates longer time frame processes which can span from rearrangment of cellular junctions-contacts to overt structural changes within the vessel wall (for example thickening of the muscle layer). These adaptive processes may enable the forces of contraction to be maintained without continued energy expenditure and damage to the vessel per se. However, they can also contribute to long-term alterations in the control of blood pressure and perhaps contribute to states of hypertension as well as other common vascular diseases. For these studies we will use arterioles, isolated by microsurgical techniques, together with sophisticated computer and video-based approaches. These techniques allow arterioles to be studied under controlled conditions and relevant biochemical measurements performed. We will also use a cell model where cultured cells will be studied after defined periods of mechanical stimulation (for example stretch). Cells will be probed using a novel microscopic technique (atomic force microscopy) which enables the cell membrane to be studied with respect to changes in composition as well as physical characteristics (for example stiffness). The studies are relevant to our understanding of the normal adaptive processes occurring within blood vessels to control blood flow and pressure. The studies are also of direct relevance to our understanding of common vascular disease states including hypertension, complications of diabetes and chronic inflammatory disorders.Read moreRead less
Characteristics Of Splice Variants Of The Skeletal Muscle Ryanodine Receptor: Implications For Myotonic Dystrophy
Funder
National Health and Medical Research Council
Funding Amount
$258,000.00
Summary
The project is to address some of the basic molecular changes that occur in skeletal muscle during development and in myotonic dystrophy. Myotonic dystrophy is a significant health issue since it is the most common adult muscular dystrophy, with an occurrence of ~1 in 7000. The results will provide much needed information about the membrane-associated molecular mechanisms that regulate muscle contraction and may provide a basis for drug design and treatment of myotonic dystrophy. Respiration and ....The project is to address some of the basic molecular changes that occur in skeletal muscle during development and in myotonic dystrophy. Myotonic dystrophy is a significant health issue since it is the most common adult muscular dystrophy, with an occurrence of ~1 in 7000. The results will provide much needed information about the membrane-associated molecular mechanisms that regulate muscle contraction and may provide a basis for drug design and treatment of myotonic dystrophy. Respiration and locomotion depend on the release of calcium ions from stores inside muscle cells. Ryanodine receptor calcium channels regulate calcium release from the stores. The essential nature of ryanodine receptors is underlined by death at or before birth when ryanodine receptor expression is defective. In addition genetic defects in the ryanodine receptor cause cardiac arrhythmias, malignant hyperthermia and central core disease. Ryanodine receptor function is compromised in heart failure and fatigue. The essential role of ryanodine receptors makes them a potential therapeutic target, but they are not used in this way because of our limited knowledge of the protein. Myotonic dystrophy is an autosomal dominant multi-system disorder, in which an expansion of non-coding DNA leads to changes in expression of several different proteins. Although the genetic basis of myotonic dystrophy is now reasonably well understood, the contribution of molecular changes in the affected proteins to the myopathy has not been investigated. Our group has recently discovered that the juvenile form of the ryanodine receptor protein is highly expressed in adults suffering from myotonic dystrophy. By discovering more about the properties of the juvenile isoform, we will understand more about the basic mechanisms of ryanodine receptor function in developing muscle and in myotonic dystrophy and be able to design drugs to specifically modify ryanodine receptor activity.Read moreRead less
Understanding The Mechanisms Of Substrate And Ubiquitin Lysine Specificity During Ubiquitination
Funder
National Health and Medical Research Council
Funding Amount
$573,993.00
Summary
Ubiquitin is a small molecule which controls all facets of a cell's growth and biology, such as growth. Ubiquitin functions by being attached to proteins in cells to alter their function and hence a particular chemical pathway. How ubiquitin is attached to proteins is poorly understood. This studiy will unveil how enzymes termed Ubcs attach ubiquitin to proteins, which is fundamental to understanding how ubiquitn controls cell functions.
Investigation Of The Roles Of Calcium-dependent Proteases In Muscle Damage And Disease
Funder
National Health and Medical Research Council
Funding Amount
$360,160.00
Summary
Muscle strength is important to the health and well-being of everyone. Skeletal muscle weakening occurs as a result of certain disease states, aging and prolonged inactivity due to illness-injury-surgery. This can result in the loss of normal activity and mobility and an increased incidence of falls and accidents, which impact considerably on health care costs. There is a family of proteins called calpains that have been linked to a number of factors affecting muscle function, however it is not ....Muscle strength is important to the health and well-being of everyone. Skeletal muscle weakening occurs as a result of certain disease states, aging and prolonged inactivity due to illness-injury-surgery. This can result in the loss of normal activity and mobility and an increased incidence of falls and accidents, which impact considerably on health care costs. There is a family of proteins called calpains that have been linked to a number of factors affecting muscle function, however it is not known how they are involved. Calpains are proteases, ie. they destroy other proteins, and they are regulated by the concentration of calcium inside a cell. The calcium concentration increases dramatically inside a muscle cell when it contracts. Inside a muscle cell it is important that there is tight regulation of the calpains to avoid them being activated inappropriately during normal use and causing muscle damage. In certain disease states, such as types of muscular dystrophy, it is known that the calcium concentration within resting muscle fibres is increased compared with healthy muscle fibres. We propose that as a consequence of this, the calpains will be less regulated and will cause damage to the muscle, which contributes to the muscle weakness seen in these diseases. Whilst calpains have been implicated with symptoms associated with muscle dystrophies, the role they play is certainly unclear. The objectives of our research proposal are to understand what factors influence i) where the calpains are located and ii) when and how much they are activated, within muscle fibres. We will compare this in healthy muscle and muscle from mdx mice, an animal model of Duchenne muscular dystrophy.Read moreRead less
Molecular Basis Of Voltage Dependent-activation Of HERG K+ Channels
Funder
National Health and Medical Research Council
Funding Amount
$439,500.00
Summary
The rhythm of the normal heart beat is controlled by electrical signals mediated by the flow of electrically charged atoms called ions. The flow of ions across heart cell membranes is predominantly mediated by proteins called ion channels that open and close in response to changes in the voltage across the cell membrane. One of these channels, called the HERG channel, has some unusual properties. Most notably, HERG channels open very slowly following an electrical stimulus, so slowly that they d ....The rhythm of the normal heart beat is controlled by electrical signals mediated by the flow of electrically charged atoms called ions. The flow of ions across heart cell membranes is predominantly mediated by proteins called ion channels that open and close in response to changes in the voltage across the cell membrane. One of these channels, called the HERG channel, has some unusual properties. Most notably, HERG channels open very slowly following an electrical stimulus, so slowly that they do not fully open until the end of the cardiac contraction cycle. These channels are therefore particularly well placed to help suppress arrhythmias initiated by premature or ectopic beats. We propose to undertake a detailed investigation into the mechanisms by which HERG channels open and close and to determine why activation of these channels is so slow. These results will provide a greater understanding of how HERG channels work and how the normal activity of HERG channels helps to suppress abnormal heart rhythms.Read moreRead less
Role Of Nitric Oxide And Reactive Oxygen Species In Excitation-contraction Coupling In Skeletal Muscle.
Funder
National Health and Medical Research Council
Funding Amount
$163,250.00
Summary
Excitation-contraction (E-C) coupling is a term used to broadly describe the sequence of cellular events that starts with an electrical signal at the surface membrane of a muscle cell and which then ultimately leads to muscle contraction. Although the overall sequence is known, there remain many gaps in our understanding of the mechanisms involved not only related to normal muscle function but to how this function may be impaired by excessive exercise and disease. Many cellular metabolites contr ....Excitation-contraction (E-C) coupling is a term used to broadly describe the sequence of cellular events that starts with an electrical signal at the surface membrane of a muscle cell and which then ultimately leads to muscle contraction. Although the overall sequence is known, there remain many gaps in our understanding of the mechanisms involved not only related to normal muscle function but to how this function may be impaired by excessive exercise and disease. Many cellular metabolites contribute towards the normal control of muscle contraction, while others contribute to its impairment. Reactive oxygen species (ROS), which includes nitric oxide (NO) and related molecules, are metabolic factors often referred to as cellular oxidants. They are thought to have an essential role in controlling normal muscle function. Paradoxically, they are also implicated in the impairment of muscle function associated with fatigue, disease and aging. How these molecules both control normal muscle activity and also contribute to impairment of such function remains unclear. Thus, the central aim of this project is to identify the mechanisms by which the cellular oxidants, NO and other ROS, both control normal E-C coupling in skeletal muscle fibres and how they contribute to muscle fatigue. Clearly, understanding how skeletal muscle normally contracts is essential in order to better understand how muscle function can become impaired with exercise, disease and age. The work from this study will provide insight into both normal muscle physiology and how muscles fatigue and ultimately provide new methodologies and drugs that may combat fatigue, disease and age related changes to muscle function.Read moreRead less