Identification And Characterisation Of Phenotypic Modifier Genes In Familial Alzheimer's Disease
Funder
National Health and Medical Research Council
Funding Amount
$413,250.00
Summary
Alzheimer's disease (AD) is the most common cause of dementia the fourth most common cause of death. There are no effective cures for AD and those drugs currently available are of very limited value in delaying the onset and progression of this invariably fatal disease. AD is diagnosed by two key features in the brain, dense plaques composed of the amyloid beta peptide, and tangles composed of the tau protein. The identification of new therapeutic targets, such as the enzymes which produce amylo ....Alzheimer's disease (AD) is the most common cause of dementia the fourth most common cause of death. There are no effective cures for AD and those drugs currently available are of very limited value in delaying the onset and progression of this invariably fatal disease. AD is diagnosed by two key features in the brain, dense plaques composed of the amyloid beta peptide, and tangles composed of the tau protein. The identification of new therapeutic targets, such as the enzymes which produce amyloid beta peptide, and the development of drugs that interact with these targets offers the prospect of developing treatments to delay disease onset, retard or even halt the development of this relentlessly progressive disease. Our research focuses on the genes that are involved in variant forms of AD. One neuropathological variant form we and others have described is characterised by large diffuse (cotton wool) amyloid plaques. Cotton wool plaque pathology is associated with AD causing mutations in the presenilin 1 (PS-1) gene. Another clinical AD variant that we have described is characterised by the presence of spastic paraparesis (SP). SP is associated with PS-1 mutations, but when present delays disease onset. We have identified two potential modifier genes which are likely to be directly involved in the production of cotton wool plaques or modifying the effect of PS-1 mutations and the occurence of SP. For both genes, the goal of this project is to use a range of genetic approaches to clone the modifier genes by and to assess their effects on the clinical and pathological development of AD. By studying the effects of genes which act to modify the effects of the PS-1 mutations in these variant forms of AD we hope to gain a greater understanding of how the plaques and tangles actually lead to the clinical symptoms of the disease and to gain insights into new ways in which AD may be treated.Read moreRead less
Cystic fibrosis is a life-threatening disease of the lungs and digestive system. It is the most common single gene disorder of Caucasian populations and most of the moratility is caused by the presence of chronic lung infections, most notably with the bacterial pathogen, Pseudomonas aeruginosa. Despite the cystic fibrosis gene being discovered over 10 years ago we still have no clear indication as to how defects in the CF gene cause susceptibility to bacterial infections, and result in the infla ....Cystic fibrosis is a life-threatening disease of the lungs and digestive system. It is the most common single gene disorder of Caucasian populations and most of the moratility is caused by the presence of chronic lung infections, most notably with the bacterial pathogen, Pseudomonas aeruginosa. Despite the cystic fibrosis gene being discovered over 10 years ago we still have no clear indication as to how defects in the CF gene cause susceptibility to bacterial infections, and result in the inflammation of the lung. Our studies address this issue by examining thechanges of gene expression in response to infection with Pseudomonas aeruginosa and therefore provide us with routes to therapies which are targetted against CF gene mediated inflammation.Read moreRead less
Modifying Factors And Phenotype Heterogeneity In Familial Hypertrophic Cardiomyopathy
Funder
National Health and Medical Research Council
Funding Amount
$394,405.00
Summary
Familial Hypertrophic Cardiomyopathy (FHC) is an inherited disorder characterised by abnormal thickening of heart muscle, resulting in clinical symptoms in affected individuals ranging from mild symptoms, to heart failure and sudden death. FHC is the commonest cause of sudden death in individuals aged less than 35 yrs in our community, and is caused by defects in genes (DNA) important in the heart's cellular structure and function. Understanding and identifying the molecular steps involved in ho ....Familial Hypertrophic Cardiomyopathy (FHC) is an inherited disorder characterised by abnormal thickening of heart muscle, resulting in clinical symptoms in affected individuals ranging from mild symptoms, to heart failure and sudden death. FHC is the commonest cause of sudden death in individuals aged less than 35 yrs in our community, and is caused by defects in genes (DNA) important in the heart's cellular structure and function. Understanding and identifying the molecular steps involved in how this defect in our DNA can lead to the clinical features of FHC, is the focus of the research described in this project. A common occurrence in families with FHC is the identification of two affected individuals within the same family (e.g. siblings) and who therefore have the same genetic defect, with variable clinical outcomes. For example, one sibling may have no symptoms and live a normal life, while his-her sibling, may develop severe symptoms, heart failure, and-or early sudden death. The reason for such diversity in clinical features, even amongst individuals with the same genetic defect, most likely reflects secondary modifying factors, e.g. genetic and-or environmental factors which modulate the expression of the primary FHC-causing gene defect. This project will focus on identifying and studying such modifying factors. One aspect of the project will focus on the identification of a genetic modifier which has been shown to exist in a genetically-engineered mouse model of FHC. A second aspect of the proposed research will focus on potential environmental factors, including pharmacological agents which may prevent disease progression, dietary factors, e.g. caffeine intake, and lifestyle factors , e.g. exercise. Through these studies, it is hoped that key molecules and important pathogenic mechanisms will be identified, leading to the development of potentially new therapies, to both treat, and ultimately prevent or cure this inherited cardiac disorder.Read moreRead less
Mapping Of Genetic Traits In Experimental Models Using Databases
Funder
National Health and Medical Research Council
Funding Amount
$237,750.00
Summary
The project aims to detect genes that influence human traits. These traits could be a disease such as diabetes or they may be much less sinister, representing hearing range as an example. Many of these traits are difficult to detect because they are governed by many genes which may also interact with the environment to influence the trait. In order to detect genes in these traits we would like to simplify the complex interactions by eliminating the environment as a potential cause or concentrati ....The project aims to detect genes that influence human traits. These traits could be a disease such as diabetes or they may be much less sinister, representing hearing range as an example. Many of these traits are difficult to detect because they are governed by many genes which may also interact with the environment to influence the trait. In order to detect genes in these traits we would like to simplify the complex interactions by eliminating the environment as a potential cause or concentrating on a particular population where the incidence appears to be much greater. In human populations we have no control over the environmental exposures and we cannot restrict their movements. For this reason many genetic studies have been conducted in mice. Many strains of mice have been generated. Their environment can be strictly controlled, enabling a much better identification of disease genes. Since mice and humans share much of their genome they also share many of their genes and are often afflicted by the same diseases. Thus if we identify genes in mice we have a very good chance of identifying the equivalent human genes. The completion of sequencing for the human genome is being closely followed by the completion of the mouse genome, precisely because mice have been used for over 100 years for genetic studies. The data generated from these sequencing efforts and prior genetic studies is now accumulating in vast databases. These databases of DNA information can be used to map genes for traits. The idea is to determine the trait measurement for many mice in different strains and compare these trait levels to the DNA state (genotype) of markers in the genome of the strains. If these are associated it indicates that the marker is situated close to a gene influencing the trait. This narrows the search considerably. Without this strategy we would have the daunting task of identifiying trait genes from many thousands of potential candidates.Read moreRead less
The Influence Of Alpha Actinins On Human Performance
Funder
National Health and Medical Research Council
Funding Amount
$542,500.00
Summary
There is a wide variation in skeletal muscle function in the general population. At one end of the spectrum are elite athletes who excel in a specialised area of sprint, power or endurance performance, while at the other end of the spectrum are individuals with muscle weakness due to inherited muscle disease. Part of this variation in human muscle performance is due to the genetic makeup of the individual. For example, world class sprinters have muscles which are genetically predisposed to gener ....There is a wide variation in skeletal muscle function in the general population. At one end of the spectrum are elite athletes who excel in a specialised area of sprint, power or endurance performance, while at the other end of the spectrum are individuals with muscle weakness due to inherited muscle disease. Part of this variation in human muscle performance is due to the genetic makeup of the individual. For example, world class sprinters have muscles which are genetically predisposed to generate maximal force at high speed. Similarly, the severity of muscle disease in an affected individual is influenced, in part, by other genes that affect normal muscle performance. The genes responsible for normal variations in muscle function in humans are unknown. The alpha-actinins are structural components of skeletal muscle. The two forms of alpha-actinin in skeletal muscle interact with a number of proteins involved in human muscle disease and thus likely contribute to the severity of muscle weakness in affected patients. Alpha-actinin-3 is present only in fast (type 2) fibres - the muscle fibres responsible for perfomance at high speed. We have identified a genetic change that results in absence of this protein in 1 in 5 people in the general population, without causing disease. We now have evidence that this genetic change, and hence whether or not muscle contains alpha-actinin-3, influences muscle performance in elite athletes. We will now use a variety of approaches to study the alpha-actinins in normal and diseased skeletal muscle. We will study the effect of changes (mutations) in the alpha-actinins in the muscle cells grown in the laboratory and in animal models. This work will impact on our understanding of how normal skeletal muscle functions, and the factors that influence human diversity in the general population.Read moreRead less