Truncating Presenilin Mutations And Their Effects On Gamma-secretase Activity, Tau And Beta-catenin
Funder
National Health and Medical Research Council
Funding Amount
$414,005.00
Summary
Alzheimer's disease (AD) and cancer are increasingly important both in terms of human suffering and the burden of care it imposes on society and the economy. Sporadic (non-inherited) AD is the most common form of dementia but is poorly understood. The PRESENILIN genes, PSEN1 and PSEN2, are the major sites for mutations causing inherited AD and are also implicated in cancer. Using the zebrafish embryo model we have discovered that, contrary to current thought, mutations that truncate presenilin p ....Alzheimer's disease (AD) and cancer are increasingly important both in terms of human suffering and the burden of care it imposes on society and the economy. Sporadic (non-inherited) AD is the most common form of dementia but is poorly understood. The PRESENILIN genes, PSEN1 and PSEN2, are the major sites for mutations causing inherited AD and are also implicated in cancer. Using the zebrafish embryo model we have discovered that, contrary to current thought, mutations that truncate presenilin proteins potently suppress normal presenilin activity. (They are so called, dominant negatives). This means that they are lethal for embryo development and explains why such mutations have never been found in inherited AD. Notably, this discovery could only be made using a subtle form of gene manipulation that is possible in zebrafish embryos. Our work has also established the first assay for the non-apoptotic (non-cell death) function of PSEN2 and has shown that PSEN2 activity is inhibited by truncated PSEN1. This is the first indication of possible interaction between PSEN1 and PSEN2 proteins at normal physiological expression levels. Loss of presenilin activity promotes cancer. Truncated presenilin proteins could be produced by errors in gene transcription (aberrant transcript splicing) common in cancerous cells. This suggests that truncated, dominant negative forms of presenilin produced through aberrant splicing (or mutation in precancerous cells) might be common in tumour formation. The proposed research will define the region of PSEN1 in which truncation leads to dominant negative activity. This will allow further examination of the role of presenilins in the cell signalling pathways involved in AD and cancer. We will also investigate the role that age-related truncation of presenilins in human cells can play in the formation of sporadic AD. This may reveal a common molecular link between the inherited and sporadic forms of this disease.Read moreRead less
Improving The Phenotypic Severity Of Intellectual Disability And Seizures Caused By Expanded Polyalanine Tract Mutations In The ARX Homeobox Transcription Factor.
Funder
National Health and Medical Research Council
Funding Amount
$683,622.00
Summary
Intellectual disability is frequent in the population, with as many as 1 in every 50 people in the world directly affected. ARX is a gene mutated in X chromosome-linked intellectual disability and seizures. Our study will comprehensively address the basis for improvements to disease outcomes following treatment with steriod horomones in mice modelling these mutations. We will also address the mechanism contributing to disturbed protein function due to these expanded polyalanine tract mutations.
High Resolution Mapping Of Genomic Regions Implicated In Migraine
Funder
National Health and Medical Research Council
Funding Amount
$392,545.00
Summary
Migraine is a frequent, debilitating and painful disorder that affects a significant proportion of the population. Using the diagnostic criteria of the international Headache Society, the prevalence of migraine has been estimated to be approximately 12%, with a recent study in the United States showing that migraine affects 4% of children, 6% of men and 18% of women. The aetiology of migraine is unknown and there are no laboratory based diagnostic tests to identify those who suffer from the diso ....Migraine is a frequent, debilitating and painful disorder that affects a significant proportion of the population. Using the diagnostic criteria of the international Headache Society, the prevalence of migraine has been estimated to be approximately 12%, with a recent study in the United States showing that migraine affects 4% of children, 6% of men and 18% of women. The aetiology of migraine is unknown and there are no laboratory based diagnostic tests to identify those who suffer from the disorder. Clinical diagnosis is currently based on patient symptom descriptions, with individual symptoms being shown to vary with age. Migraine is believed to have a genetic basis with specific environmental factors, such as particular foods, hormonal levels and fatigue, being capable of inducing attacks in predisposed individuals. Migraine shows strong familial aggregation with about 50% of those affected, having another close relative also affected with the disorder. At present the number of genes involved in the disorder is unknown and have not been identified. Recent studies in our laboratory have localised two migraine genes, one to chromosome 19 and the other to the X chromosome. More recently we have also found evidence for a third gene on chromosome 1. This study is aimed at fine scale mapping analysis of these three chromosomal regions in order to pinpoint the location of migraine genes. Our ultimate aim is to identify the molecular causes of this disorder. This would have important implications to both the diagnosis and treatment of migraine.Read moreRead less
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
Chronic or extreme reactions to stress can lead to pathological conditions such as long term anxiety states, depression and panic disorders. Stress related disease also contributes to other major health problems such as heart disease and disorders of the immune system. These disease states include some of the major medical problems of our times. This proposal is to define genes which may be involved in stress responsiveness, to further understand and treat stress related disease.
Fainting (syncope) is a common disorder leading to blackouts, which can cause injury. Breath-holding is a related problem in younger children also resulting in blackouts. Both of these conditions can run in families but little is known about what causes these events. We will study large families to identify the genes underlying these common phenomena. This will deepen our understanding of patterns of inheritance, improve genetic counseling, and lead to better diagnostic and treatment options.
Cloning And Characterisation Of A Bipolar Disorder Susceptibility Gene On Chromosome 15q
Funder
National Health and Medical Research Council
Funding Amount
$347,621.00
Summary
Bipolar disorder is a severe mood disorder, characterised by aberrant mood swings resulting in periods of mania and depression. We need to define more clearly the biological basis of bipolar disorder to improve diagnosis and treatment. Bipolar disorder is highly heritabile allowing the use of genetics to identify the predisposing genes. Our aim is to identify a bipolar susceptibility gene on chromosome 15 and to understand how this gene contributes to the risk of developing bipolar disorder.
Genetic Analysis Of Migraine And Comorbid Psychiatric Disorders Using Twin Families
Funder
National Health and Medical Research Council
Funding Amount
$554,450.00
Summary
Typical migraine, is a frequent, debilitating and painful disorder that normally affects people during their most productive years (up to 25% of females and 7.5% of males in Western populations). Additionally, several studies have demonstrated a cross-sectional relation between psychiatric disorders (namely anxiety and depression) and migraine in community samples. The World Health Organization (WHO) recently identified migraine and major depression among the world's top 20 leading causes of dis ....Typical migraine, is a frequent, debilitating and painful disorder that normally affects people during their most productive years (up to 25% of females and 7.5% of males in Western populations). Additionally, several studies have demonstrated a cross-sectional relation between psychiatric disorders (namely anxiety and depression) and migraine in community samples. The World Health Organization (WHO) recently identified migraine and major depression among the world's top 20 leading causes of disability, with an impact that extends far past the suffering individual, to the family and community. In both sexes of all ages, depression and migraine are the 1st and 19th leading causes of disability affected life years. Although both migraine and depression are highly prevalent in our society, their aetiologies remain relatively obscure and there are no laboratory based diagnostic tests that identify those who suffer from the disorders. Because so little is known about them, a positional cloning approach is the only feasible way to identify the molecular mechanisms underlying these disorders. This project will collect a sample with sufficient power to perform a genome wide linkage screen to i) identify novel susceptibility genes, and ii) confirm previously reported susceptibility genes for migraine and co-occurring psychiatric disorders. The susceptibility genes identified (and confirmed) in this sample will provide clues to the further elucidation of the complex molecular pathways of migraine (and co-occurring psychiatric disorders) and, finally, will help in the development of diagnostic tests and rational treatment strategies.Read moreRead less