Neurologic Effects Of Mutational Load In MELAS Syndrome
Funder
National Health and Medical Research Council
Funding Amount
$505,786.00
Summary
This project will use a new stem cell model to discover what happens to brain cells in patients with the MELAS 3243A>G mutation, a common genetic mutation found in 1-500 Australians. Brain cells will be grown from our stem cell model and used to find out how this mutation causes problems in the affected brain cells. We will find out what happens to the brain when the amount of mutation is reduced in vitro. By understanding what happens, we will be able to design new treatments for this disord ....This project will use a new stem cell model to discover what happens to brain cells in patients with the MELAS 3243A>G mutation, a common genetic mutation found in 1-500 Australians. Brain cells will be grown from our stem cell model and used to find out how this mutation causes problems in the affected brain cells. We will find out what happens to the brain when the amount of mutation is reduced in vitro. By understanding what happens, we will be able to design new treatments for this disorder.Read moreRead less
Evaluation Of Pathogenic Mechanisms Involved In Nuclear And Mitochondrial DNA-encoded Mitochondrial Disorders
Funder
National Health and Medical Research Council
Funding Amount
$196,527.00
Summary
Mitochondria produce energy for the cell. Disorders of mitochondrial function can cause human disease. These diseases are referred to as the mitochondrial disorders. Mitochondrial disorders usually involve multiple tissues, particularly the muscle and brain.These disorders are usually caused by mutations in two different types of DNA; nuclear and mitochondrial DNA. There are many forms of mitochondrial disorders; some affect young children or infants and others cause adult disease. In some cases ....Mitochondria produce energy for the cell. Disorders of mitochondrial function can cause human disease. These diseases are referred to as the mitochondrial disorders. Mitochondrial disorders usually involve multiple tissues, particularly the muscle and brain.These disorders are usually caused by mutations in two different types of DNA; nuclear and mitochondrial DNA. There are many forms of mitochondrial disorders; some affect young children or infants and others cause adult disease. In some cases, genetic defects may cause the same disease and other mutations may cause a wide range of symptoms. The reason why this occurs is unknown. This study investigates several factors that may determine why some mutations lead to a certain disease and why others may cause different diseases. These factors include the variation in energy levels that are produced by the mutant cells, and the different levels of vunerability that mutated cells may have to induced cell death. The goal of this proposal is to identify the factors that lead to mutations causing different clinical symptoms with the overall aim being to design treatment for these chronic diseases.Read moreRead less
Defining The Genomic Basis Of Mitochondrial Complex I Deficiency
Funder
National Health and Medical Research Council
Funding Amount
$639,682.00
Summary
The human genome project led to new technologies that will revolutionise genetic testing. Previously, we could only sequence genes one at a time. Next Generation sequencing allows analysis of hundreds or thousands of genes simultaneously. We will analyse 90 genes in 100 children with severe disorders of mitochondrial energy generation. This will provide proof of principle for the introduction of this technology into routine medical testing and identify new genes causing these diseases.
The Role Of Mitochondrial DNA In Age-related Hearing Loss
Funder
National Health and Medical Research Council
Funding Amount
$260,475.00
Summary
Hearing loss is an extremely common and under-studied age-related disability, affecting 39% of Australians aged 50 years or older. Both genetic and environmental factors may contribute to the development of age-related hearing loss. Human genetic material (DNA) resides in two places in body cells; the nucleus and in organelles called mitochondria. This is due to the fact that mitochondria were derived from bacteria that were engulfed by the cell back in primordial life. Although this genetic mat ....Hearing loss is an extremely common and under-studied age-related disability, affecting 39% of Australians aged 50 years or older. Both genetic and environmental factors may contribute to the development of age-related hearing loss. Human genetic material (DNA) resides in two places in body cells; the nucleus and in organelles called mitochondria. This is due to the fact that mitochondria were derived from bacteria that were engulfed by the cell back in primordial life. Although this genetic material is different to nuclear DNA, it has an essential role in helping to provide energy for the cell. Genetic mutations in the DNA residing in the mitochondria have been associated with a number of conditions, usually affecting tissues that require large amounts of energy, such as the brain, muscle, heart, retina and the cochlea of the ear. The commonest clinical manifestation of mitochondrial disease is thought to be hearing loss. This project investigates the role that abnormal mitochondrial DNA plays in the development of hearing impairment by studying subjects from a representative Australian community who participated in a large population study of hearing loss. We will assess whether different sectors of mitochondrial DNA predispose particular individuals to the development of hearing loss or accelerate its onset. The Blue Mountains Hearing Study is able to take into account other factors known to be associated with hearing loss (industrial noise exposure, diabetes, smoking).Read moreRead less
Molecular Basis Of Mitochondrial Complex I Deficiency, The Most Common Energy Generation Disorder
Funder
National Health and Medical Research Council
Funding Amount
$515,750.00
Summary
Oxygen is needed by every cell in the body to burn fuels (ie sugar, fat and protein) in small power plants inside each cell called mitochondria. In Australia, about 50 children born each year have inherited disorders of mitochondrial energy generation. The most severe disorders cause infant death, while others cause a range of degenerative diseases later in life, particularly affecting brain, muscle and heart. In most cases we do not have any effective treatments. A major problem in understandin ....Oxygen is needed by every cell in the body to burn fuels (ie sugar, fat and protein) in small power plants inside each cell called mitochondria. In Australia, about 50 children born each year have inherited disorders of mitochondrial energy generation. The most severe disorders cause infant death, while others cause a range of degenerative diseases later in life, particularly affecting brain, muscle and heart. In most cases we do not have any effective treatments. A major problem in understanding mitochondrial energy generation disorders is that the genetic causes are incredibly diverse. So far more than 20 genes have been shown to cause mitochondrial disorders, and it is likely that over one hundred more genes remain to be discovered. In addition to the regular genes that cause these and other genetic disorders, mitochondria are unique in carrying 37 extra genes located in a different part of the cell away from the rest of the human genome, and inherited only from the mother. This grant focuses on the most common energy generation disorder, known as Complex I deficiency. Complex I requires 43 separate components to be assembled together in order to work properly, but mutations in the 43 genes encoding these components are not present in most patients. We believe that the most common problems will be in genes involved in assembling the 43 components rather than in the components themselves. We will use a number of methods to pinpoint where in the genome the causative genes are located and then home in on the exact changes in the genes that cause disease. Identifying these genes will allow us to improve future diagnosis and prevention of mitochondrial disease. Understanding the basic biology may also allow us to develop new methods of treatment. Recent studies suggest that milder mitochondrial problems also contribute to a range of more common diseases such as diabetes and Parkinson disease, so any new treatments could potentially have wide application.Read moreRead less
Pathogenesis Of Antiretroviral Induced Sub-cutaneous Fat Wasting
Funder
National Health and Medical Research Council
Funding Amount
$331,650.00
Summary
The use of potent antiretroviral therapy has resulted in great clinical and survival benefit in patients with HIV infection and has in most cases, outweighed the risk of short term side effects. However, not that survival of patients with AIDS has considerably improved the long-term complications of chronic therapy have become a critical issue. Lipodystrophy syndrome(s) is the name given to a set of changes to blood lipids, glucose levels and body habitus and typically occurs in those successful ....The use of potent antiretroviral therapy has resulted in great clinical and survival benefit in patients with HIV infection and has in most cases, outweighed the risk of short term side effects. However, not that survival of patients with AIDS has considerably improved the long-term complications of chronic therapy have become a critical issue. Lipodystrophy syndrome(s) is the name given to a set of changes to blood lipids, glucose levels and body habitus and typically occurs in those successfully treated with anti-HIV therapy. The facial and body habitus changes are common, progressive and are frequently disfiguring. Aside from the psychological and social effects of such changes, many patiens are not able to retain their anonymity as HIV infected individuals. In addition, changes to blood lipids may lead to atherosclerosis. Already there have been several case reports of premature coronary disease in young HIV infected patients. It is increasingly difficult for patients to remain strictly adherent to chronic therapy because of all these concerns. There is an urgent need to understand the exact biological cause(s) of lipodystrophy syndrome(s) in HIV infected patients in order to help identify which of our currently available antiretroviral therapies will offer the long term clinical and survival benefit of strong viral suppression without increasing risk of vascular disease. Based on results of our previous studies on lipodystrophy syndrome, we have proposed that lipodystrophy may be the result of antiviral drugs depleting the DNA content of mitochondria within fat cells. We propose to examine sequential fat biopsy specimens from HIV infected volunteers to determine whether antiretroviral therapy has had adverse effects on mitochondrial DNA content and-or function.Read moreRead less
Identifying Novel Genes Causing Cytochrome C Oxidase (COX) Deficiency
Funder
National Health and Medical Research Council
Funding Amount
$426,917.00
Summary
Our bodies convert food into energy in tiny cellular power plants called mitochondria. Each year about 50 Australian children inherit disorders of mitochondrial energy generation. The most severe disorders cause infant death, while others cause degenerative diseases in later life, particularly affecting brain and muscle. In most cases we lack effective treatments. The genetic causes of mitochondrial disorders are incredibly diverse, with over 70 disease genes known. Some are located on the uniqu ....Our bodies convert food into energy in tiny cellular power plants called mitochondria. Each year about 50 Australian children inherit disorders of mitochondrial energy generation. The most severe disorders cause infant death, while others cause degenerative diseases in later life, particularly affecting brain and muscle. In most cases we lack effective treatments. The genetic causes of mitochondrial disorders are incredibly diverse, with over 70 disease genes known. Some are located on the unique mitochondrial DNA we inherit only from our mothers. Many more genes await discovery. This study focuses on the mitochondrial disorder cytochrome c oxidase (COX) deficiency, for which we have diagnosed 80 Australian patients. COX requires 13 separate components to be assembled together in order to work properly, but mutations in the genes encoding these components are not present in most patients. We believe that the most common problems will be in genes involved in assembling the components rather than in the components themselves. We will use a number of methods to pinpoint where in the genome the disease genes are located. A key to our strategy is identifying patients likely to have mutations in the same gene. We have identified two such groups, and will do studies that involving fusing two cell lines together to confirm they have the same disorder. We will then perform genetic mapping to look for regions of similarity in the genome using DNA (SNP) chips. We will test how well the genes in such regions are expressed, whether we can correct the problem in cultured skin cells by introducing a healthy copy of that chromosome, and look for gene mutations. Identifying these genes will allow us to improve future diagnosis and prevention and may allow us to develop new methods of treatment. Milder mitochondrial problems also contribute to a range of more common diseases such as diabetes and Alzheimer disease, so any new treatments could potentially have wide applicationRead moreRead less
Genetic Variation Of Mitochondrial Complex I: Its Role In Rare And Common Diseases
Funder
National Health and Medical Research Council
Funding Amount
$628,415.00
Summary
Our bodies convert food into energy in tiny cellular power plants called mitochondria. Each year about 50 Australian children inherit disorders of mitochondrial energy generation. The most severe disorders cause infant death, while others cause degenerative diseases in later life, particularly affecting brain and muscle. In most cases we lack effective treatments. The genetic causes of mitochondrial disorders are incredibly diverse, with over 70 disease genes known. Some are located on the uniqu ....Our bodies convert food into energy in tiny cellular power plants called mitochondria. Each year about 50 Australian children inherit disorders of mitochondrial energy generation. The most severe disorders cause infant death, while others cause degenerative diseases in later life, particularly affecting brain and muscle. In most cases we lack effective treatments. The genetic causes of mitochondrial disorders are incredibly diverse, with over 70 disease genes known. Some are located on the unique mitochondrial DNA we inherit only from our mothers. Many more genes await discovery. This grant focuses on the most common energy generation disorder, known as Complex I deficiency. Complex I requires 46 separate components to be assembled together in order to work properly, but mutations in the 46 genes encoding these components only seem to explain disease in about half of all patients. Our aim is to identify new disease genes and to determine whether some patients have mutations in two different genes that interact to cause disease, rather than in a single gene. We will use a number of methods to pinpoint where in the genome the causative genes are located and then home in on the exact changes in the genes that cause disease. Identifying these genes will allow us to improve future diagnosis and prevention of mitochondrial disease. We will also generate mice in which one of the Complex I genes has been knocked out. These mice will allow us to better understand the basic disease mechanisms that link gene changes to disease. Understanding the basic biology may allow us to develop new methods of treatment. The mouse models will also be useful for trialling new treatments and for investigating the role of milder mitochondrial problems in common diseases such as diabetes and Parkinson disease. Any new treatments could potentially have wide application.Read moreRead less
First Generation Mouse Models Of MtDNA Disease: Testing Genotype/phenotype Predictions
Funder
National Health and Medical Research Council
Funding Amount
$256,527.00
Summary
Mitochondrial diseases comprise a diverse group of inherited diseases affecting infants, children and adults. These disorders result from defective energy production by the mitochondria, tiny structures in all cells which have their own unique DNA. This mitochondrial DNA is inherited only from our mothers. To make energy for cells to function normally, special enzymes are produced in the mitochondria from mitochondrial and nuclear genes. In their most severe form mitochondrial disease results in ....Mitochondrial diseases comprise a diverse group of inherited diseases affecting infants, children and adults. These disorders result from defective energy production by the mitochondria, tiny structures in all cells which have their own unique DNA. This mitochondrial DNA is inherited only from our mothers. To make energy for cells to function normally, special enzymes are produced in the mitochondria from mitochondrial and nuclear genes. In their most severe form mitochondrial disease results in infants with muti-system failure. Adult forms are less severe, with symptoms including epilepsy, cardiomyopathy, late-onset blindness or deafness, and commonly diabetes. We do not understand why different mitochondrial mutations result in such diverse symptoms, and no therapies have been consistently successful. Unusual features of mitochondrial DNA has meant that it has remained beyond the reach of techniques which are commonly used now to produce mice with altered genes. These so-called 'mouse models' are powerful tools to better understand human diseases and importantly, to enable experimental therapies to be tested and improved. This grant proposes a novel method of producing such mouse models, for the first time allowing mice with different levels of defective mitochondrial function to be produced to model the human diseases. In the proposed work, mitochondria from different mouse species will be introduced into laboratory mice. This unusual approach is based on previous work by the investigators who have shown that this produces defective mitochondria in cultured mouse cells. These mice will be allowed to age and the function of mitochondria from different organs tested as the animals age. Secondly, a range of mitochondrial DNA mutations will be produced in cultured cells and mutants selected to make other mice which should accurately model the diverse human diseases.Read moreRead less