Glutathione is a natural antioxidant, which is known to protect cells in the body from chemical damage. A small part of the glutathione in cells is found in the mitochondria, a structure that is involved in producing the chemical energy needed for normal cell function. The mitochondria are also involved under some circumstances in promoting the death of cells. Although glutathione in general has been well studied, much less attention has been paid to the function of glutathione in mitochondria, ....Glutathione is a natural antioxidant, which is known to protect cells in the body from chemical damage. A small part of the glutathione in cells is found in the mitochondria, a structure that is involved in producing the chemical energy needed for normal cell function. The mitochondria are also involved under some circumstances in promoting the death of cells. Although glutathione in general has been well studied, much less attention has been paid to the function of glutathione in mitochondria, particularly in cells from the brain. Our recent studies indicate that this mitochondrial pool of glutathione is particularly important in limiting the death of cells from the brain when exposed to damaging substances that are increased in some diseases. Thus, the capacity of mitochondrial glutathione to deal with such substances might be a factor in determining the extent of cell loss in the brain, which is an important determinant of symptoms in some of the major neurological diseases. Consistent with this possibility, we have obtained evidence indicating that decreases in glutathione in the mitochondria contribute to the cell death and brain damage that results from a stroke. In our proposed studies, we will investigate the function of mitochondrial glutathione in the two major cell populations from the brain, neurons and astrocytes. We will characterise the protective role of the glutathione and investigate how it enters the mitochondria and what factors influence the amount that is present. This will provide new insights into the function of glutathione in the mitochondria and could also suggest novel approaches for manipulating this antioxidant pool. We will also study models of stroke and some related brain disorders to more directly test the role of this antioxidant in disease and to assess whether manipulating the content of glutathione in the mitochondria has the potential to reduce damage and improve function in these disordersRead moreRead less
Viral Interference With Apoptosis: Defining The Mechanisms And Effects On Viral Pathogenesis
Funder
National Health and Medical Research Council
Funding Amount
$551,328.00
Summary
Apoptosis, or programmed cell death, is an orderly process whereby unwanted or damaged cells are removed from an organism. Deregulation of apoptosis has been implicated in the development of diseases such as cancer and autoimmunity. Therefore, a precise understanding of the mechanisms controlling the initiation of apoptosis has important clinical implications. In addition to removing unwanted cells, apoptosis functions as a defence mechanism to inhibit viral replication. Hence, in order to repli ....Apoptosis, or programmed cell death, is an orderly process whereby unwanted or damaged cells are removed from an organism. Deregulation of apoptosis has been implicated in the development of diseases such as cancer and autoimmunity. Therefore, a precise understanding of the mechanisms controlling the initiation of apoptosis has important clinical implications. In addition to removing unwanted cells, apoptosis functions as a defence mechanism to inhibit viral replication. Hence, in order to replicate efficiently viruses have evolved means to inhibit or interfere with apoptosis. The central aim of this work is to understand how two genes encoded by murine cytomegalovirus (MCMV) inhibit apoptosis and contribute to viral replication. MCMV is used as a model for human CMV (HCMV) infection. The majority of the human population is infected with HCMV which poses no risk to healthy individuals. However, reactivation of HCMV in people who are immunosuppressed such as transplant recipients or AIDS patiens is a significant cause of mortality. The MCMV infection model has provided important insights as to how the immune system controls infection and the mechanisms utilized by viruses to circumvent these processes. The proposed studies will improve our understanding of the processes that regulate viral replication. Understanding how viruses subvert host defence mechanisms will allow us to better understand their role in causing human disease, and thus, will provide key information for the design of improved anti-viral strategies. Importantly, the type of analyses proposed here will also contribute critical insights into the normal processes that control cell survival.Read moreRead less
Cell death by a specialised process known apoptosis is a way of deleting unwanted and harmful cells from the body. As such, aberrant apoptosis is associated with a wide array of diseases including cancer. For example, abnormal levels of proteins that suppress apoptosis or enhance cell survival can result in cancer and often produce resistance to chemotherapy. To understand and treat cancers that result from aberrant apoptosis we need to know at a molecular level how apoptosis is regulated. Centr ....Cell death by a specialised process known apoptosis is a way of deleting unwanted and harmful cells from the body. As such, aberrant apoptosis is associated with a wide array of diseases including cancer. For example, abnormal levels of proteins that suppress apoptosis or enhance cell survival can result in cancer and often produce resistance to chemotherapy. To understand and treat cancers that result from aberrant apoptosis we need to know at a molecular level how apoptosis is regulated. Central to the apoptosis execution are a group of enzymes called caspases that target many cellular proteins for specific cleavage. In this proposal, we will investigate the function of one of the caspases (called caspase-2), in order to better understand its potential role in the apoptosis of cancer cells. A number of recent reports suggest that caspase-2 levels are reduced in many cancer cells. The human caspase-2 gene localizes to a chromosomal region frequently affected- deleted in leukaemia, and caspase-2 levels have been proposed to be predictors of remission and survival in patients with some types of leukaemia. We will study if loss of caspase-2 in cancer cells makes them resistant to killing by drugs and if mice lacking caspase-2 have an increased potential to develop cancer. Understanding caspase-2 function and its regulation is likely to provide new therapeutic opportunities and potential targets for cancer therapy.Read moreRead less
The Role Of Central And Peripheral Synaptic Activity In The Developmental Death Of Motoneurons.
Funder
National Health and Medical Research Council
Funding Amount
$463,145.00
Summary
Information processing in the nervous system relies on the effective communication between neurons and their target cells which make up our neuronal circuitry. At the centre of all this is the synapse, the specialized contact between a neuron and its target cell, be it another neuron in the brain or a target organ such as skeletal muscle. Our primary goal is to determine how the formation of synaptic connections during development regulates neuronal survival. In this proposal we have focussed on ....Information processing in the nervous system relies on the effective communication between neurons and their target cells which make up our neuronal circuitry. At the centre of all this is the synapse, the specialized contact between a neuron and its target cell, be it another neuron in the brain or a target organ such as skeletal muscle. Our primary goal is to determine how the formation of synaptic connections during development regulates neuronal survival. In this proposal we have focussed on the neuromotor system as it is a well characterised part of the nervous system. During development, 50% of motoneurons die at a time when they are making contact with skeletal muscle, and when contacts onto motoneurons by other neurons are being established. We believe that the formation of effective synaptic contacts onto motoneurons, as well as connections by motoneurons onto muscle are the key regulators of motoneuron survival. We are in a position to be able to address what regulates motoneuron death; as we have a number of mice which lack key molecules needed for the formation of specialisations that allow neuronal contacts to be made between motor neurons and their muscle, and with other neurons within the spinal cord. By examining the function of motoneurons, counting them and screening for molecular changes in these mice, we will be able to dissect out the mechanism of how a motoneurons' fate is determined during developmental motoneuron death. This research could help in developing strategies aimed at improving neuronal connections to improve neuronal viability. Our research will have important implications for our understanding about the basis of adult neuro-degenerative diseases, such as motor neuron disease and Alzheimer's, which are in part characterised by a molecular breakdown in neuronal connections that ultimately result in neuronal death.Read moreRead less
Investigation Of Sudden Cardiac Death In The Young
Funder
National Health and Medical Research Council
Funding Amount
$682,823.00
Summary
Sudden cardiac death is a major tragedy in young people. In approximately one third of such cases, no cause of death is found at autopsy. This study will investigate the causes of sudden cardiac death in the young, with a specific emphasis on the underlying genetic causes of sudden unexplained death. This information will be used for screening surviving family relatives, thereby improving both diagnostic and treatment-prevention opportunities and reducing sudden cardiac death in our community.
The Regulation And Role Of Puma And P53 In IL-3 Withdrawal Induced Cell Death
Funder
National Health and Medical Research Council
Funding Amount
$527,683.00
Summary
It is the ultimate fate of most of our cells to die by committing suicide, because they are no longer required, are no longer functioning, or are potentially harmful. This normal physiological process is termed apoptosis . When cell death fails to occur, abnormal cells can accumulate and lead to cancer. Signalling from growth-factors is required for many cell types to survive. When these signals are lost, the cells activate their cell death pathways. It is a hallmark of cancer cells that they ha ....It is the ultimate fate of most of our cells to die by committing suicide, because they are no longer required, are no longer functioning, or are potentially harmful. This normal physiological process is termed apoptosis . When cell death fails to occur, abnormal cells can accumulate and lead to cancer. Signalling from growth-factors is required for many cell types to survive. When these signals are lost, the cells activate their cell death pathways. It is a hallmark of cancer cells that they harbour mutations in cell death genes and their dependence on growth factors for survival is diminished or lost. The genes of the apoptosis pathway function either to promote or inhibit cell death. Some genes in the apoptosis pathway allow apoptosis to proceed rapidly, but do not decide the fate of the cell. Other genes are required for a cell to commit to die, and if they are mutated then a functional cell, that is capable of proliferating, survives. This is a crucial distinction because it is only the genes that decide cell fate that can act as cancer genes, and are valid targets for therapy. We have identified one particular gene, Puma, as an important regulator of cell survival. Without this gene, cells survive longer without growth-factor and, importantly, can proliferate when growth factor is restored. Understanding how this gene functions and is regulated will contribute to our understanding of the gene mutations that lead to cancer and may identify valid targets for cancer therapy. In our model we use growth factor dependent cell lines derived from mice lacking particular genes in the cell death pathway, including Puma. These cells proliferate in the presence of growth factor, and allow us to determine the role of the genes when growth factor is withdrawn. Using this system, we will determine how Puma is able to induce cell death, what other genes are required to regulate this process and how loss of Puma function may contribute to cancer development.Read moreRead less
Mortality In Young Offenders Who Have Had Custodial Sentences
Funder
National Health and Medical Research Council
Funding Amount
$60,448.00
Summary
The proposal seeks funding to investigate the death rate in young people who have received custodial sentences. There is evidence in the literature and anecdotal evidence from workers in the field that young offenders are at particularly high risk of dying from drug overdose, violently or by suicide, yet deaths in this group have not yet been investigated in Australia. As far as we are aware, there are also no reports worldwide of standardised mortality rates for young offenders who have been in ....The proposal seeks funding to investigate the death rate in young people who have received custodial sentences. There is evidence in the literature and anecdotal evidence from workers in the field that young offenders are at particularly high risk of dying from drug overdose, violently or by suicide, yet deaths in this group have not yet been investigated in Australia. As far as we are aware, there are also no reports worldwide of standardised mortality rates for young offenders who have been incarcerated. A group of young people who have received their first custodial sentences between 1988 and 1999 in Victoria will be identified, starting with 10 year olds in 1988. Their details will then be matched with data held by The National Death index, housed at the Australian Institute of Health and Welfare, and with the Victorian Coroner's data in order to identify deaths that have occurred, the cause of death and the circumstances of death. This will provide an index of the excess deaths experienced by this group of young offenders compared with Victorian population data for the same age group and gender. Further analysis will elucidate cause specific mortality, will enable the identification of subgroups at particular risk and the examination of trends over time. The study will provide a solid foundation for health priorities, the development of interventions and policy in relation to young offenders. It will provide a resource for Australasia and be of worldwide interest. Juvenile offenders are a well-defined group who has extended contact with support services. There is a unique opportunity for the delivery of interventions aimed at improving the welfare and adult outcomes of this enormously disadvantaged and marginalised section of our community. The Centre for Adolescent Health, as the auspicing body for the Adolescent Forensic Health Service is in an excellent position to respond to this challenge.Read moreRead less
Mitochondria: Molecular And Cellular Insights Into Their Diverse Contributions To Neuronal Injury
Funder
National Health and Medical Research Council
Funding Amount
$747,927.00
Summary
Mitochondria are components of cells normally providing energy for essential functions and in the energy demanding brain, under stress conditions, mitochondria acts as controllers of cellular decision-making processes leading to neuronal death. Our goal is to understand mitochondrial mechanisms determining how neurones die after various stresses and injury. Using pathological insults relevant to neurological conditions, we shall analyse death molecules and how neurones adapt when threatened.
Cardiac Arrhythmias And Cardiac Contractility During Stress: Regulation By Brainstem Medullary Raph Neurons
Funder
National Health and Medical Research Council
Funding Amount
$425,250.00
Summary
Life is stressful, and in subjects with predisposed hearts stressful events may provoke sudden life-threatening or fatal disturbances of the heart rhythm (arrhythmias). Activity in nerves that control the heart is the main trigger of arrhythmias. This activity is initiated in the brain, when, for example, we have a sudden emotional shock. At present, the neurochemistry and connections of the brain neurons responsible for arrhythmias, have not been identified. Our project is designed to find answ ....Life is stressful, and in subjects with predisposed hearts stressful events may provoke sudden life-threatening or fatal disturbances of the heart rhythm (arrhythmias). Activity in nerves that control the heart is the main trigger of arrhythmias. This activity is initiated in the brain, when, for example, we have a sudden emotional shock. At present, the neurochemistry and connections of the brain neurons responsible for arrhythmias, have not been identified. Our project is designed to find answers to these questions. Our hypothesis is that the responsible neurons are located in the midline portion of the medulla oblongata (the lower part of the brain); that activation of these neurons will increase cardiac function in a manner that may provoke arrhythmias; and, conversely, that their inhibition will protect the heart during stressful events by suppressing potentially arrhythmogenic neural signals. We hypothesise that cardiac-controlling neurons possess receptors for serotonin (one of the brain neurotransmitters), and that the neurons can be inhibited by drugs that selectively activate a specific subtype of these receptors. Our results will increase our understanding of the causes of cardiac arrhythmias by elucidating the link between emotional-psychological events in the brain and stress-induced cardiac events. Our findings could contribute to the identification of new drugs that will protect the heart during stress.Read moreRead less
Molecular Mechanisms Of Death In Cells With Defective Apoptotic Pathways
Funder
National Health and Medical Research Council
Funding Amount
$335,065.00
Summary
The body protects itself from cancer by killing any cell that poses a risk of becoming a tumour. The body kills these cells via a carefully orchestrated sequence (or pathway) of events, however many cancer cells have defects in cell death pathways that has permitted them to survive even though they have been told to die. In this proposal we set out a research program to investigate how to kill cancer cells that don't want to die. Various tumour cells have been shown to have increased levels of B ....The body protects itself from cancer by killing any cell that poses a risk of becoming a tumour. The body kills these cells via a carefully orchestrated sequence (or pathway) of events, however many cancer cells have defects in cell death pathways that has permitted them to survive even though they have been told to die. In this proposal we set out a research program to investigate how to kill cancer cells that don't want to die. Various tumour cells have been shown to have increased levels of Bcl-2, a proto-oncogene that blocks cell death induced by diverse stimuli. Cells that over-express Bcl-2 are also resistant to cytotoxic drugs. Understanding how to bypass Bcl-2 (or proteins that block cell death in tumours) will lead to a better understanding of cell death-cell survival and allow us to explore the possibility of tailoring treatment for patients in which specific defects in death pathways have been identified in their cancer cells. Cytotoxic lymphocytes (CL) are cells of the immune system that defend the body from cancer by specifically attacking and killing tumor cells. We have been pioneering studies of CL:tumour interactions in which we can define the morphology and kinetics of critical events in cell death and have shown that CL have the ability to kill target cells that over-express Bcl-2. Following the aims in this proposal, we will understand the mechanisms by which cytotoxic lymphocytes kill target cells that have defects in classical cell death pathways. These studies will therefore define alternative pathways to cell death in the event that a key component of the preferential pathway to cell death is inoperative. Since cytotoxic lymphocytes use a variety of ways to kill their targets and tumors may contain multiple defects in cell death pathways, we will explore which are the key defects, or the combination of multiple defects, in cell death pathways that prevent cytotoxic lymphocyte mediated cell death and permit tumour survival in vivo.Read moreRead less