The Role Of Androgens In Osteoblast Development And Bone Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$64,631.00
Summary
Male hormones are essential for the growth and maintenance of bone in men, but exactly how and when they act on the bone forming cells is unclear. We aim to find out what happens when the target for male hormones (receptor) is removed in the bone forming cells at different stages of their development. This project will increase our understanding of how male hormones regulate bone formation and may assist in the design of new therapies for osteoporosis.
Feeding Behaviour And Obesity Development: Identification Of Novel Intervention Points
Funder
National Health and Medical Research Council
Funding Amount
$923,668.00
Summary
Appetite and food intake is regulated by specific neuronal structures in the brain. The most important area is the hypothalamus from which many neuronal pathways originate to control specific aspects of feeding behaviour and energy usage in the brain and the rest of the body. To better understand the contribution individual neuronal populations make to drive excess food intake we propose a new approach to identify this, making new treatment options for eating disorders and obesity possible.
Epilepsy is an important human disease because it causes physical trauma and sudden death in addition to immense social and economic hardship. The genetic basis of a number of epilepsy syndromes has been identified but the precise mechanism whereby mutations produce seizures is unknown. Several mutations in the alpha4 neuronal nicotinic receptor (a4 nAChR) gene have been identified in Autosomal Dominant Nocturnal Frontal Lobe Epilepsy (ADNFLE). This is a rare form of inherited epilepsy character ....Epilepsy is an important human disease because it causes physical trauma and sudden death in addition to immense social and economic hardship. The genetic basis of a number of epilepsy syndromes has been identified but the precise mechanism whereby mutations produce seizures is unknown. Several mutations in the alpha4 neuronal nicotinic receptor (a4 nAChR) gene have been identified in Autosomal Dominant Nocturnal Frontal Lobe Epilepsy (ADNFLE). This is a rare form of inherited epilepsy characterized by the presence of seizures during light sleep. In vitro studies using the human mutated DNA (i.e. DNA containing the genetic defect) have suggested that this mutation results in reduced activity of the receptor. Therefore a mouse in which this gene is destroyed would be relevant in understanding the human disease. We have generated an a4 nAChR knockout (KO) mouse and plan to use the mouse to test the idea that loss of function of the a4 nAChR in vivo is associated with enhanced seizure activity. The KO mice do not have unprovoked seizures but appear to have an increased number of major motor seizures in response to pentylenetetrazole, an agent which is known to cause seizures by blocking the effects of the brain inhibitory molecule GABA. Interestingly, a4 nAChRs are known to control the release of GABA. We therefore propose that our knockout mice have seizures because they tend to under produce GABA. We will also make and analyse a mouse line with the same genetic mutation as patients with ADNFLE. The experiments are aimed at understanding the way that seizures are generated and spread in the brain in these rare forms of epilepsy. The hope is that understanding these mechanisms will help us better understand and therefore treat common forms of epilepsy.Read moreRead less
The Effect Of PKC Epsilon On The Insulin Receptor And Whole Body Glucose Homeostasis.
Funder
National Health and Medical Research Council
Funding Amount
$82,261.00
Summary
Increased fat availability is strongly associated with insulin resistance and type 2 diabetes. Data from this lab has shown animals lacking a particular enzyme (Protein Kinase C epsilon) are able to compensate for this insulin resistance and maintain normal blood glucose levels by elevating insulin availability, with a major site of action being the liver. This project therefore aims to examine the action of PKC epsilon on insulin clearance by the liver.
Distinct Populations Of Arc NPY Neurons Control Different Aspects Of Energy Homeostasis
Funder
National Health and Medical Research Council
Funding Amount
$843,340.00
Summary
Obesity is caused by an imbalance of energy intake and energy expenditure both of which are controlled by specific neurons in the brain. While different types of neurons important in these processes have been identified how they are organised and work in fulfilling the different functions is unclear. Here we aim to identify subpopulations of neurons that are responsible for specific tasks that would make them more specific targets for drug intervention with a reduced risk of side effects.
Investigation Of Transgenic Mouse Models Of Type 2 Diabetes
Funder
National Health and Medical Research Council
Funding Amount
$412,200.00
Summary
Type 2 diabetes is a common condition characterised by high blood glucose, that afflicts 700,000 Australians. It causes blindness, kidney failure and an increased risk of heart attack and stroke. despite intensive study over many years, the reasons for the elevated blood glucose in this condition are not fully understood. Several abnormalities can contribute to the high glucose and different researchers have proposed different defects as the initial cause. It has proven difficult to unravel the ....Type 2 diabetes is a common condition characterised by high blood glucose, that afflicts 700,000 Australians. It causes blindness, kidney failure and an increased risk of heart attack and stroke. despite intensive study over many years, the reasons for the elevated blood glucose in this condition are not fully understood. Several abnormalities can contribute to the high glucose and different researchers have proposed different defects as the initial cause. It has proven difficult to unravel the sequence of events in the evolution of the syndrome because high glucose can cause insulin resistance and a defect in insulin secretion, both of which can lead to high blood glucose. One approach to study the consequences of specific defects is to genetically engineer them. The aims of this project are to: 1. make a mouse with reduced ability to store glucose in muscle. 2. test the metabolic consequences of a defect in the manufacture of glycogen (starch) in muscle. 3. study the effects of combining a defect in glucose storage with one that results in an oversupply of glucose. 4. study the effects on a mouse with a genetic predisposition for failure of beta cells (insulin making cells) of a defect in muscle glucose storage and over production of glucose. A successful completion of this grant will greatly enhance our understanding of how blood glucose is increased in Type 2 diabetes.Read moreRead less
Identifying The Physiological Actions Of Calcitonin
Funder
National Health and Medical Research Council
Funding Amount
$683,040.00
Summary
Calcitonin is a hormone whose main action has long been regarded as the slowing down of bone breakdown, however, its importance in human physiology is unknown. The aim of this study is to understand the role of calcitonin in regulating bone formation and protecting the skeleton in times of calcium stress, such as lactation. These results will greatly advance our understanding of the control of bone and calcium homeostasis, which will have implications for the treatment of bone disorders.
Failure of bone healing leads to significant pain and disability, such that augmentation of fracture repair is a dynamic and important field of study. A full understanding of bone repair is necessary before we can hope to introduce novel successful therapies. We believe that a improved understanding of the origins of the cells involved with bone healing may lead to new surgical, drug and cell-based therapies for the treatment of recalcitrant bone repair. Stem cells originating from the bone marr ....Failure of bone healing leads to significant pain and disability, such that augmentation of fracture repair is a dynamic and important field of study. A full understanding of bone repair is necessary before we can hope to introduce novel successful therapies. We believe that a improved understanding of the origins of the cells involved with bone healing may lead to new surgical, drug and cell-based therapies for the treatment of recalcitrant bone repair. Stem cells originating from the bone marrow and periosteum are known to differentiate into mature bone cells and produce bone. However, these tissues are damaged or have poor access to the site of bone injury in many severe open fractures. In these cases, bone repair often initiates in a region adjacent to an opposing muscle. This has led us to speculate that cells from the muscle may directly contribute to bone repair. Published studies, which have be confirmed by our group, have demonstrated the strong potential for muscle-derived progenitor cells (satellite cells) to become bone-like in response to stimuli such as bone morphogenic proteins. To put bone-forming potential of muscle cells in perspective, we plan to expand on these studies and compare mouse satellite cells with mouse bone marrow stem cells. In addition, we plan to use a transgenic mouse whose muscle cells become permanently genetically transformed to stain blue. This mouse will allow us to assess the fate of muscle cells and their contribution to bone formation in ectopic bone formation and fracture repair models. This study will explore on the most basic level the cellular contribution of muscle to bone repair. The results of this research project will significantly influence our therapeutic directions for improving fracture repair in the future.Read moreRead less
The Physiological Role Of Calcitonin And Its Receptor In Bone Cell Metabolism.
Funder
National Health and Medical Research Council
Funding Amount
$496,446.00
Summary
Throughout adult life, bone tissue is continuously remodelled. The two main processes involved in bone remodelling, are bone formation and bone breakdown. Bone formation is controlled by cells known as osteoblasts and bone breakdown is controlled by cells known as osteoclasts. Under normal circumstances these two processes are tightly coupled. Excessive breakdown of bone, causes these two processes to become unbalanced and results in bone loss. This is the basis of many bone diseases such as ost ....Throughout adult life, bone tissue is continuously remodelled. The two main processes involved in bone remodelling, are bone formation and bone breakdown. Bone formation is controlled by cells known as osteoblasts and bone breakdown is controlled by cells known as osteoclasts. Under normal circumstances these two processes are tightly coupled. Excessive breakdown of bone, causes these two processes to become unbalanced and results in bone loss. This is the basis of many bone diseases such as osteoporosis, a condition in which the bones become fragile and therefore more susceptible to fracture. 1 in 2 women and 1 in 3 men aged 70 years and older suffer from osteoporosis in Australia. Despite this, the mechanisms which control osteoclast breakdown of bone are not well understood. Our laboratory is interested in how hormones affect osteoclast action. We plan to examine the role of the hormone calcitonin, an important inhibitor of osteoclastic bone breakdown. This will be achieved by studying transgenic mice in which the receptor, or target, for calcitonin is specifically removed from osteoclasts. This will allow us to precisely determine the role of calcitonin in osteoclast function. Data generated by our research group indicates that calcitonin is also involved in controlling bone formation, however, the way in which calcitonin acts on osteoblasts remains poorly understood. Therefore, studying our transgenic mice will also help clarify the role calcitonin plays in bone formation. Current treatment for osteoporosis involves the administration of drugs which inhibit bone breakdown. This project will increase our understanding of how calcitonin acts to regulate bone breakdown and bone formation and may assist in the design of new therapies for osteoporosis. We believe that this research is of great importance as osteoporosis is becoming more prevalent as the population ages.Read moreRead less
Cell-selective Deletion Of Brain AT1A Receptors In Hypertension: Effect On Blood Pressure, Increased ROS Production And Inflammation.
Funder
National Health and Medical Research Council
Funding Amount
$578,268.00
Summary
Angiotensin is important for normal regulation of blood pressure but is also involved in cardiovascular diseases. Interruption of angiotensin’s actions is a common treatment of these diseases. Functional deletion of angiotensin receptors decreases blood pressure. Surprisingly the site(s) in the body responsible for this decrease are not known. We will examine the role of angiotensin receptors in the brain in the control of blood pressure in health and in cardiovascular disease.