Characterisation Of A Novel Family Of Skeletal Muscle Gene Regulators
Funder
National Health and Medical Research Council
Funding Amount
$443,250.00
Summary
Muscle cells may be broadly divided into two classes, slow- or fast-twitch, with different physiological and biochemical properties. These properties are largely determined by the protein products of several multi-gene families that encode the contractile apparatus characteristic of muscle cells. The pattern of expression of these muscle-specific genes defines a muscle cell as either a slow-twitch or fast-twitch myofibre. Skeletal muscle is inherently plastic in its ability to express different ....Muscle cells may be broadly divided into two classes, slow- or fast-twitch, with different physiological and biochemical properties. These properties are largely determined by the protein products of several multi-gene families that encode the contractile apparatus characteristic of muscle cells. The pattern of expression of these muscle-specific genes defines a muscle cell as either a slow-twitch or fast-twitch myofibre. Skeletal muscle is inherently plastic in its ability to express different genes in response to altered functional demand, and under certain circumstances, fibres can convert from one type to another. Conditions known to cause myofibre conversion in humans include congenital myopathies, spinal injury, and exercise. We have identified a novel family of proteins that regulate the genes that confer fibre type. In this proposal, we will further characterise the function of each of these proteins in skeletal muscle development and fibre determination. In addition, the gene that encodes these proteins is one of many deleted in the human condition Williams-Beuren Syndrome (WBS). WBS is characterised by supravalvular aortic stenosis (SVAS), neurological and cognitive defects, infantile hypercalcemia, dental malformations, musculoskeletal anomalies and growth retardation with short stature. The musculoskeletal anomalies, including joint contractures, muscular pain and kyphoscoliosis, cause WS patients to lack stamina and fatigue easily. An underlying myopathy has been reported and may account for the physical limitations, however the disease causing gene-genes have not been identified. We predict that a lack of the MusTRD proteins contributes to these conditions. In general, the findings from our study will yield insights that will lead to improved treatments of patients who suffer from muscle disease or have sustained a nerve injury and improved approaches to excercise training.Read moreRead less
Restoring Skeletal Muscle In An Experimental Model Of COPD By Targeting The IGF-1-myostatin-macrophage Axis
Funder
National Health and Medical Research Council
Funding Amount
$508,183.00
Summary
Most people think that the serious disabilities of COPD (emphysema) patients follows damage to their lungs but wasted muscles may be even more important. We can not regrow lung but we have found a way that might help regrow muscle. We plan to use stem cells to make one of the body's own cells called 'macrophages' and genetically engineer these cells to help deliver healing proteins directly into the muscle. Making muscle stronger will help COPD patients live longer and improve quality of life.
THE ROLES OF CYTOSKELETAL PROTEINS IN SKELETAL MUSCLE FUNCTION AND DISEASE
Funder
National Health and Medical Research Council
Funding Amount
$466,650.00
Summary
Congenital myopathies are inherited diseases of skeletal muscle that typically present at birth or in early chilhood and are characterised by poor muscle tone and muscle weakness. This group of disorders includes nemaline myopathy, central core disease, congenital fiber type disproportion, and myotubular myopathy. All of these disorders are characterised by disorganisation of the sarcomere, the major structure within skeletal muscle cells that is involved in contraction. In nemaline myopathy pat ....Congenital myopathies are inherited diseases of skeletal muscle that typically present at birth or in early chilhood and are characterised by poor muscle tone and muscle weakness. This group of disorders includes nemaline myopathy, central core disease, congenital fiber type disproportion, and myotubular myopathy. All of these disorders are characterised by disorganisation of the sarcomere, the major structure within skeletal muscle cells that is involved in contraction. In nemaline myopathy patients, mutations have been found in five genes that encode proteins of the filamentous systems of the sarcomere. Therefore, the genes for other thin filament, thick filament and Z-line proteins are excellent candidates for these disorders. Research from our lab has identified a novel region of the sarcomere and the genes encoding the proteins present in this region provide additional candidates for the congenital myopathies. We will further characterise the proteins in this novel structure to determine its function and the role that it plays in muscle disease pathologies. In order to study the relationship between disease pathology and muscle weakness in nemaline myopathy, we generated a mouse model by expressing a mutant protein, a-tropomyosin slow, found in human patients in mice. All features of the disease found in humans are present in the mice. A key feature of this disease in mice is the ability for muscle cells to grow in diameter or hypertrophy to offset the muscle weakness. We will use these mice to trial therapies including hypertropy-inducing agents, to prevent and reverse muscle weakness. In addition, we will generate an additional mouse model for this disease with a mutation in a gene encoding another filamentous protein. A comparison of the two models using microarray analysis will help us identify additional genes that are being affected in this disease and to generate a molecular expression profile that will aid in the diagnosis of this disease.Read moreRead less
Novel Features And Mechanisms Of Congenital Myopathies
Funder
National Health and Medical Research Council
Funding Amount
$464,500.00
Summary
Congenital myopathies are inherited diseases of skeletal muscle that typically present at birth or in early childhood and are characterised by poor muscle tone and muscle weakness. This group of disorders includes nemaline myopathy, central core disease, congenital fiber type disproportion, and myotubular myopathy. All of these disorders are characterised by disorganisation of the sarcomere, the major structure within skeletal muscle cells that is involved in contraction. In addition, the congen ....Congenital myopathies are inherited diseases of skeletal muscle that typically present at birth or in early childhood and are characterised by poor muscle tone and muscle weakness. This group of disorders includes nemaline myopathy, central core disease, congenital fiber type disproportion, and myotubular myopathy. All of these disorders are characterised by disorganisation of the sarcomere, the major structure within skeletal muscle cells that is involved in contraction. In addition, the congenital myopathies have features in common with virtually all muscle diseases such as slow fibre predominance and alterations in contractile force. We are using nemaline myopathy as a representative congenital myopathy to examine features in common amongst the myopathies, characteristic of the congenital myopathies and specific to nemaline myopathy. In nemaline myopathy patients, mutations have been found in five genes that encode proteins of the filamentous systems of the sarcomere. A feature specific to nemaline myopathy is the presence of abnormal structures of the sarcomere called nemaline rods. We have analysed a large number of nemaline myopathy patients that have mutations in the genes that encode the filament proteins alpha-skeletal actin and tropomyosin. In addition, we have generated mouse models for nemaline myopathy and propose to generate an additional one with novel features. Our mouse model has revealed that a feature previously thought exclusive to dystrophies, is also present in nemaline myopathy. The combined analysis of well-characterised patient samples and mouse models will allow us to address longstanding questions about this particular congenital myopathy and myopathies in general. We will determine how rods form and their protein composition. Our mouse models in particular will allow us to address the molecular mechanisms that underpin the increase in slow twitch fibres and the effects that a particular mutation has on muscle function.Read moreRead less
Inherited Muscle Disorders - Gene Discovery, Pathobiology And Therapy.
Funder
National Health and Medical Research Council
Funding Amount
$1,750,277.00
Summary
The project proposed by Professors Nigel Laing and Kathryn North and Dr Kristen Nowak is based upon the results of their successful identification of disease genes for genetic muscle diseases. The project is divided into three parts. In the first part of the project, the research team will identify further novel disease genes, some of which they are already close to finding. In the second part of the project the team will determine how the mutations they have identified in the disease genes actu ....The project proposed by Professors Nigel Laing and Kathryn North and Dr Kristen Nowak is based upon the results of their successful identification of disease genes for genetic muscle diseases. The project is divided into three parts. In the first part of the project, the research team will identify further novel disease genes, some of which they are already close to finding. In the second part of the project the team will determine how the mutations they have identified in the disease genes actually cause the diseases. The aim of this work is to discover targets that may ultimately lead to new therapies for these muscle diseases. In the third and final part of the project, the team will pursue one possible therapeutic approach, which is based upon the understanding of the diseases the researchers have gained from their previous studies. There are currently no cures for these muscle diseases, though symptoms can be treated. The team will determine whether heart actin can replace muscle actin in skeletal muscle and thus might treat the muscle disease.Read moreRead less
Structural And Functional Consequences Of LMNA Gene Mutations
Funder
National Health and Medical Research Council
Funding Amount
$357,904.00
Summary
Heart failure due to diseases of the heart muscle is a leading cause of illness and death in Australia. It has recently been discovered that mutations (changes in the DNA sequence) in genes in the heart are an important cause of heart muscle disease. In many cases, these gene mutations are passed from generation to generation in families. Mutations in the LMNA gene have been found to cause abnormalities of the heart s contraction and rhythm. The LMNA gene encodes two proteins, lamins A and C, th ....Heart failure due to diseases of the heart muscle is a leading cause of illness and death in Australia. It has recently been discovered that mutations (changes in the DNA sequence) in genes in the heart are an important cause of heart muscle disease. In many cases, these gene mutations are passed from generation to generation in families. Mutations in the LMNA gene have been found to cause abnormalities of the heart s contraction and rhythm. The LMNA gene encodes two proteins, lamins A and C, that are located in the muscle cell nucleus. The role of lamins A and C in the heart and the mechanism by which mutant proteins cause heart muscle disease are unknown. We propose to address these questions by studying a mouse model in which lamins A and C have been knocked out. We will also perform in vitro experiments to examine the effects of LMNA mutations that have been found in affected families. These studies will contribute to a better understanding of the causes of heart muscle disease and will ultimately lead to new approaches to the diagnosis and treatment of patients with heart failure and disturbances of heart rhythm.Read moreRead less
Conditional Knockout Of The Murine Patched Gene For The Study Of Skin Differentiation And Cancer.
Funder
National Health and Medical Research Council
Funding Amount
$423,564.00
Summary
Basal cell carcinoma (BCC) is the most common cancer in Australia. We recently isolated the BCC gene, Patched (PTCH) from analysis of patients with Naevoid Basal Cell Carcinoma Syndrome (NBCCS). Individuals with NBCCS have a wide variety of developmental defects in addition to a cancer predisposition which includes medulloblastoma, rhabdomyosarcoma and ovarian fibroma as well as multiple BCCs. This application proposes the generation of an animal model for skin development and cancer by selectiv ....Basal cell carcinoma (BCC) is the most common cancer in Australia. We recently isolated the BCC gene, Patched (PTCH) from analysis of patients with Naevoid Basal Cell Carcinoma Syndrome (NBCCS). Individuals with NBCCS have a wide variety of developmental defects in addition to a cancer predisposition which includes medulloblastoma, rhabdomyosarcoma and ovarian fibroma as well as multiple BCCs. This application proposes the generation of an animal model for skin development and cancer by selectively removing patched gene function from specific cell of the skin. In doing this we will be able to determine the exact role of this gene in skin development, and how mutation causes common skin cancer.Read moreRead less
The Influence Of A-actinin-3 On Muscle Structure, Metabolism, Performance And Response To Diet And Disease
Funder
National Health and Medical Research Council
Funding Amount
$624,355.00
Summary
We have identified a common genetic variant that results in absence of the fast muscle fibre protein a-actinin-3 in more than one billion humans worldwide. Loss of a-actinin-3 influences elite athletic performance, muscle bulk and strength in the general population, response to diet and exercise, and susceptibility to developing type 2 diabetes. We will now study mice and humans to determine how this gene influences variations in human performance, metabolism and severity of muscle disease.