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
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.
Evolutionary Conservation Of Caspase Regulatory Mechanisms
Funder
National Health and Medical Research Council
Funding Amount
$585,215.00
Summary
Apoptosis is a highly controlled process by which metazoans eliminate unwanted and dangerous cells. Dysregulation of apoptosis can contribute to many conditions including cancer, autoimmune and degenerative diseases. To develop therapeutic reagents that promote cell death when it fails to occur, or prevent it from happening inappropriately, it is necessary to understand the mechanisms controlling apoptosis. To date, many of the important insights into mammalian cell death signalling have been in ....Apoptosis is a highly controlled process by which metazoans eliminate unwanted and dangerous cells. Dysregulation of apoptosis can contribute to many conditions including cancer, autoimmune and degenerative diseases. To develop therapeutic reagents that promote cell death when it fails to occur, or prevent it from happening inappropriately, it is necessary to understand the mechanisms controlling apoptosis. To date, many of the important insights into mammalian cell death signalling have been informed by studies of apoptotic pathways in simpler, experimentally tractable model organisms. This project will exploit biochemical approaches and powerful yeast-based tools developed by CI-A to further explore cell death pathways of the nematode Caenorhabditis elegans, and compare these with mammalian apoptosis pathways. Key findings will be verified using genetic approaches. Most apoptotic stimuli ultimately kill mammalian, insect or nematode cells by triggering activation of proteases termed caspases. However, the mechanisms by which caspase activity is regulated appear to differ somewhat between mammals and worms. We will address two general possibilities: either these animals really do differ significantly in the upstream regulation of cell death pathways, or that functional counterparts of key components have not hitherto been identified or fully characterised. Understanding the way in which mammalian apoptosis is regulated will aid in the design of diagnostic and therapeutic reagents for the many diseases in which dysregulation of apoptosis has been implicated. This project seeks to define the extent to which apoptotic regulation is conserved between mammals and nematodes. This knowledge will enable researchers to maximise the utility of nematode cell death models for the further elucidation of mammalian cell death regulatory mechanisms, and to explore how apoptosis can be manipulated for clinical benefit.Read moreRead less
Cell death by a special process called apoptosis is a means of deleting unwanted and harmful cells from the body. Extensive apoptosis occurs during foetal development which is required to get rid of many excess cells produced during the growth of the embryo. Selective apoptosis is also essential for the formation of different tissues and organs in developing foetus. In the adult, apoptosis is required for proper functioning of the immune system, to remove virus infected and cancer cells and, in ....Cell death by a special process called apoptosis is a means of deleting unwanted and harmful cells from the body. Extensive apoptosis occurs during foetal development which is required to get rid of many excess cells produced during the growth of the embryo. Selective apoptosis is also essential for the formation of different tissues and organs in developing foetus. In the adult, apoptosis is required for proper functioning of the immune system, to remove virus infected and cancer cells and, in general, to maintain the correct number of cells in the body. As such, misregulation of apoptosis is associated with the pathogenesis of a wide array of diseases. To understand, manage and treat disorders that result from aberrant apoptosis, we need to know at molecular and cellular level, how apoptosis is brought about and how it is regulated. We have been studying these processes in detail for several years. Central to the apoptotic execution of cell death are a group of proteases called caspases, that target many cellular proteins for specific cleavage. The activation of caspases is the crucial step in the initiation of apoptosis and therefore each cell has developed complex ways to control this process. If we understand how these regulatory mechanisms operate, we can then formulate strategies that are targeted towards pathologies involving abnormal apoptosis. In this proposal we will use vinegar fly as a model to study the function of caspases in development. We believe that results from this proposal will have several major benefits. Firstly, they will provide important insight into the mechanisms of developmental apoptosis thereby filling many gaps in our current knowledge. Secondly, the study will endeavour to identify new molecules-pathways that lead to caspase activation. Finally, the proposed studies will shed light on the function of caspases in non-apoptotic pathways.Read moreRead less
Identifying The Critical Components Of Growth Factor-mediated Survival Pathways
Funder
National Health and Medical Research Council
Funding Amount
$589,338.00
Summary
The regulation of cell lifespan (cell survival) is controlled by growth factors and lies at the heart of all biological processes. However, little is known of the molecular switches inside cells that either turn survival on or off. We propose to identify and characterize the molecular switches inside cells that control the balance between cell survival and death. Targeting specific components of these switches may provide new approaches for the treatment of cancer and infectious diseases.
Regulation Of P75 Death Signalling: How Neurotransmitter- And Neurotrophic- Signals Determine Cell Survival
Funder
National Health and Medical Research Council
Funding Amount
$292,216.00
Summary
Nerve cell survival is dependent on trophic support in the form of growth factors and synaptic input, both of which promote recovery after nerve injury. The survival pathways activated by growth factors are generally well characterised, whereas survival signals activated by synaptic activity are largely unexplored. This proposal aims to discover how synaptic activity prevents nerve cell death by looking at how synaptic activity inhibits the processes active in dying nerve cells.
Proteolytic Cleavage Of The P75 Neurotrophin Receptor Mediates Cell Death
Funder
National Health and Medical Research Council
Funding Amount
$238,500.00
Summary
The p75 neutrotophin receptor (p75NTR) is a major inducer of nerve cell death, and is active in a wide range of neurodegenerative conditions, including Alzheimer's disease, motor neuron disease, multiple sclerosis, stroke and nerve trauma. This study aims to understand and to characterise the events that regulate this receptor. In particular, we will investigate the role that cleavage or controlled breakdown of the receptor plays in mediating its cell death activity. A fundamental aspect of this ....The p75 neutrotophin receptor (p75NTR) is a major inducer of nerve cell death, and is active in a wide range of neurodegenerative conditions, including Alzheimer's disease, motor neuron disease, multiple sclerosis, stroke and nerve trauma. This study aims to understand and to characterise the events that regulate this receptor. In particular, we will investigate the role that cleavage or controlled breakdown of the receptor plays in mediating its cell death activity. A fundamental aspect of this proposal is determining whether cleavage is due to presenilin-dependent activity, given that presenilin mutations have been demonstrated in most familial Alzheimer s disease cases. While this will increase our understanding of one of factors contributing to Alzheimer's disease, it also has much broader implications. A wide range of pharmaceuticals which regulate presenilin cleavage are already being developed and clinically tested for their efficacy in the treatment of Alzheimer s disease. Should our research demonstrate that p75NTR cleavage is the key process that regulates neuronal degeneration it will have major ramifications for approaches to the treatment of other p75NTR-associated neurodegenerative conditions.Read moreRead less
The establishment of an immune system that is able to distinguish between self and non-self is of fundamental importance for good health and survival. How this specificity is achieved has been an area of intense investigation for many years because a breakdown of this process leads to the development of autoimmune diseases, such as diabetes, or an inability to fight pathogenic organisms. It has been known for many years that the development T cells, a subset of cells involved in mounting immune ....The establishment of an immune system that is able to distinguish between self and non-self is of fundamental importance for good health and survival. How this specificity is achieved has been an area of intense investigation for many years because a breakdown of this process leads to the development of autoimmune diseases, such as diabetes, or an inability to fight pathogenic organisms. It has been known for many years that the development T cells, a subset of cells involved in mounting immune responses, occurs in the thymus. The thymus produces large numbers of immature T cells (called thymocytes) from which a small number receive the appropriate signals to survive and develop into mature T cells. These tailor-made T cells can then enter the blood and peripheral lymphoid organs where they fight infectious organisms without reacting against host (i.e. self) tissues. The work for this project is aimed at determining how proteins inside thymocytes transmit signals that determine whether thymocytes either survive, and develop into T cells, or are eliminated because they react too strongly with self proteins. We have established that a protein called c-Cbl is central to this process as it regulates the initial strength of the signal that determines the fate of thymocytes. Our aim is to identify the putative key protein regulated by c-Cbl that can sense when a signal is too strong following the binding of a thymocyte to a self protein and directs a cell death signalling response. From this critical point of signal splitting we also aim to identify proteins that relay the death signal to the nucleus where they trigger the production of well-characterised proteins required to mediate cell death. By identifying the proteins in this signalling pathway we will have a greater capacity to control the magnitude of immune responses and therefore be able to lessen tissue damage caused by autoimmune reactions.Read moreRead less
Genetic Basis Of Sudden Cardiac Death In The Young
Funder
National Health and Medical Research Council
Funding Amount
$574,500.00
Summary
Sudden cardiac death is a devastating complication of a variety of cardiovascular disorders. In the young, sudden cardiac death can be caused by both structural abnormalities of the heart, e.g. cardiomyopathies, and electrical abnormalities of the heart, such as familial long QT syndrome. In most young sudden cardiac deaths, these cardiovascular disorders are caused by underlying gene abnormalities which place individuals at a higher risk of sudden death. The aim of this project is to understand ....Sudden cardiac death is a devastating complication of a variety of cardiovascular disorders. In the young, sudden cardiac death can be caused by both structural abnormalities of the heart, e.g. cardiomyopathies, and electrical abnormalities of the heart, such as familial long QT syndrome. In most young sudden cardiac deaths, these cardiovascular disorders are caused by underlying gene abnormalities which place individuals at a higher risk of sudden death. The aim of this project is to understanding the genetic basis of sudden cardiac deaths in the young. In particular, the study will identify and characterise the specific genes which cause sudden cardiac death, and what the underlying mechanism is regarding how a single gene defect can lead to such a devastating clinical outcome. Understanding the various cardiovascular diseases that cause sudden death, clinically screening at-risk individuals, coupled with the initiation of appropriate therapeutic and preventative strategies such as implantation of cardioverter defibrillators will most likely reduce the incidence of sudden cardiac death in the young of our community. Elucidation of the underlying genetic defects which cause many of these cardiac disorders will substantially improve diagnostic accuracy, will be invaluable for genetically screening at-risk individuals and by making the diagnosis earlier in life, will create a larger therapeutic window to allow initiation of therapies to prevent complications of disease, including sudden death.Read moreRead less