Pathophysiological Significance Of Reverse Signaling Through Membrane TNF
Funder
National Health and Medical Research Council
Funding Amount
$453,055.00
Summary
Cytokines are molecules produced by cells that take part in immune and inflammatory responses. They coordinate the activities of leukocytes and therefore are important in the host response against infections. However, overproduction of some cytokines, particularly tumour necrosis factor, seems to cause the deleterious consequences. Tumour necrosis factor is made by cells, particularly macrophages, T lymphocytes and natural killer cells, in two stages: first, the cytokine is exposed on the surfac ....Cytokines are molecules produced by cells that take part in immune and inflammatory responses. They coordinate the activities of leukocytes and therefore are important in the host response against infections. However, overproduction of some cytokines, particularly tumour necrosis factor, seems to cause the deleterious consequences. Tumour necrosis factor is made by cells, particularly macrophages, T lymphocytes and natural killer cells, in two stages: first, the cytokine is exposed on the surface of the cell and then it is 'clipped off' and released as a smaller, soluble form. In either form it can interact with specific receptors on other cells and, in this way, change the cells' activities. We believe that binding of tumour necrosis factor receptors to the cytokine while it is in its membrane form can also send a message backwards, into the cell bearing the tumour necrosis factor. This process, known as reverse signalling, then changes the activity of this cell. In this project we will investigate this phenomenon in detail. The results will be extremely relevant to new methods of treatment of diseases, that rely either on 'masking' tumour necrosis factor by administering soluble forms of its receptor or on blocking the release of the soluble form of the molecule from the surface of the cell. Our work will enable us to understand the consequences of these approaches more fully. We will also be looking at the role of the membrane form of tumour necrosis factor in a model of infectious disease. Influenza virus is responsible for a great deal of morbidity and mortality around the world. We, and others, have shown, in a mouse model, that some cells in the lungs make tumour necrosis factor during the course of viral pneumonia. Here we will determine whether the membrane form of this cytokine plays a role in clearing virus or causing some of the complications of this disease. This also may have relevance to other inflammatory and infectious disease.Read moreRead less
Regulation Of TNF Receptor Expression By Omega-6 And Omega-3 Polyunsaturated Fatty Acids
Funder
National Health and Medical Research Council
Funding Amount
$226,320.00
Summary
This project looks at two major molecules which our body generates in trying to combat infections, a protein called tumor necrosis factor (TNF) and a fatty acid called arachidonic acid. In some cases the persistent production of elevated amounts of these molecules leads to highly crippling and debilitating diseases , such as rheumatoid arthritis, which pose a huge burden to our community. To develop medication to combat these diseases be it either vaccination or antiinflammatory drugs, there is ....This project looks at two major molecules which our body generates in trying to combat infections, a protein called tumor necrosis factor (TNF) and a fatty acid called arachidonic acid. In some cases the persistent production of elevated amounts of these molecules leads to highly crippling and debilitating diseases , such as rheumatoid arthritis, which pose a huge burden to our community. To develop medication to combat these diseases be it either vaccination or antiinflammatory drugs, there is a need to clearly define key components of the inflammatory response. Since TNF acts through a receptor we propose that a critical issue in the regulation of this inflammatory response is the changes in the expression of these receptors on cells of the immune system. Our preliminary work suggests that lipid molecules such as arachidonic acid (omega-6 fat) interacts with phagocytic cells and causes drammatic changes to the expression of this receptor. Our research proposal will look at this in more detail and place the observation into perspective in terms of parameters of the inflammatory reaction and associated diseases. Furthermore this concept will be examined in relation to the protective effects which the omega-3 fats found in fish oil have on these inflammatory diseases.Read moreRead less
Regulation Of Antiviral And Antiinflammatory Responses By MTNF: Key Role Of Reverse Signaling By Host And Viral TNFR
Funder
National Health and Medical Research Council
Funding Amount
$568,501.00
Summary
New and re-emerging viral infections continue to pose a major problem. We have recently discovered a hitherto unrecognized process that the body uses to regulate its response to infection. Some viruses have evolved to target this process, underscoring its importance. We will study 2 virus models, poxvirus and influenza A, to understand how this process works during infection. We will also examine the potential to exploit this process to block pathology and influence recovery from infection.
Mapping The TNF Pathway: A Qualitative And Quantative Molecular Analysis Of The Components And Post-translational Modifications Involved In Physiological And Pathological TNFR1 Signalling
Funder
National Health and Medical Research Council
Funding Amount
$636,258.00
Summary
TNF is a master regulator of the inflammation response and dysregulated TNF signalling causes many human diseases. We will use a cutting edge mass spectrometry technique that we have developed to analyse molecules required for TNF signalling. Understanding how the TNF signalling works in all cell types and with different forms of ligands will open up therapeutic opportunities to selectively target TNF signalling in inflammatory diseases, such as Rheumatoid Arthritis and Cancer.
Critical Role Of TNF In Host-virus Interactions And Outcome Of Infection: Involvement Of Reverse Signalling Through MTNF
Funder
National Health and Medical Research Council
Funding Amount
$496,500.00
Summary
Cytokines are molecules produced by cells that take part in the immune response. They coordinate the activities of leukocytes and are important in the host response to virus infections. For their part, viruses have evolved strategies to try and evade the host response. The analysis of these strategies in the context of a viral infection will lead to a better understanding of the immune system and host-virus interactions. Tumour necrosis factor is a cytokine made by specific leukocytes, in two st ....Cytokines are molecules produced by cells that take part in the immune response. They coordinate the activities of leukocytes and are important in the host response to virus infections. For their part, viruses have evolved strategies to try and evade the host response. The analysis of these strategies in the context of a viral infection will lead to a better understanding of the immune system and host-virus interactions. Tumour necrosis factor is a cytokine made by specific leukocytes, in two stages: First, the cytokine is exposed on the surface of the cell and then it is clipped off and released as a soluble form. In either form it can interact with specific receptors on other cells and, in this way, change the cells' activities. We have found that binding of tumour necrosis factor receptors to the cytokine, while it is in its membrane form, can also send a message backwards into the cell bearing the tumour necrosis factor. This process, known as reverse signalling, then changes the activity of this cell and constitutes a major new route through which information transfer can occur. In this project we will characterize the biological changes that result from reverse signalling in specific types of leukocytes. We will be looking at the role of membrane tumour necrosis factor in two separate models of viral disease. The first is influenza pneumonia that is responsible for a great deal of morbidity and mortality worldwide. The second is a model of poxvirus infection (mousepox) that mimics the disease smallpox in humans. Human poxvirus infections are on the rise (e.g. monkeypox) and there is an increased threat of smallpox as a weapon of bioterrorism. Mousepox is a good model for the study of generalized viral infections and is also an excellent example of a virus that encodes proteins specifically designed to interfere with host tumour necrosis factor. Our studies will focus on the role of this cytokine in host-virus interactions and the outcome of infection.Read moreRead less
Preconditioning: The Molecular Basis For Protection From Hepatic Ischemia-reperfusion Injury
Funder
National Health and Medical Research Council
Funding Amount
$406,980.00
Summary
When the blood supply to the liver is cut off temporarily (ischemia) and later restored (reperfusion) the liver is damaged by a process called ischemia-reperfusion (IR) injury. This is a major problem during liver surgery and is also an underlying problem in liver transplantation; following storage of a donor liver ready for placing into the recipient it can undergo a similar process called preservation injury. We now understand a lot about how IR comes about, particularly by the formation of da ....When the blood supply to the liver is cut off temporarily (ischemia) and later restored (reperfusion) the liver is damaged by a process called ischemia-reperfusion (IR) injury. This is a major problem during liver surgery and is also an underlying problem in liver transplantation; following storage of a donor liver ready for placing into the recipient it can undergo a similar process called preservation injury. We now understand a lot about how IR comes about, particularly by the formation of damaging oxygen radicals within liver cells to start a process of programmed cell death, but it remains difficult to prevent or treat IR injury. A recent breakthrough has been recognition that subjecting the liver to only a short period (5 or 10 minutes) of ischemia protects against a later period of prolonged ischemia or IR. In the investigator s mouse model, for example, such preconditioning was 60 to 90% protective (depending on the time after IR). This project seeks to understand how preconditioning works to protect the liver against IR injury. Our idea is that preconditioning generates a limited amount of oxygen radicals, and that these turn on signalling pathways in the cell that regulate certain protective genes. Genes that encode antioxidant and other anti-stress pathways are likely to be important, but so are genes that prepare the cell to enter the cell cycle and divide into new cells that regenerate the liver. Conversely, genes that program cell death may be turned off. The outcomes of this research will be to understand the molecular and cellular basis of how preconditioning protects against ischemia-reperfusion injury of the liver. This will allow drug treatments to be devised that, by simulating preconditioning, prevent this common and severe type of liver damage.Read moreRead less
The Role Of Necroptosis In Inflammatory Skin Diseases
Funder
National Health and Medical Research Council
Funding Amount
$548,690.00
Summary
Diseases associated with exaggerated inflammation account for a large toll of human disease. We have recently described how mice with a mutation in the Sharpin gene, that causes the chronic proliferative dermatitis phenotype (cpdm), can be rescued by crossing these mice to TNF (Tumor Necrosis Factor) knock-out mice. Our findings suggest that TNF induced cell death, rather than TNF induced cytokine production, may be at the root of many inflammatory diseases and we aim to test this hypothesis in ....Diseases associated with exaggerated inflammation account for a large toll of human disease. We have recently described how mice with a mutation in the Sharpin gene, that causes the chronic proliferative dermatitis phenotype (cpdm), can be rescued by crossing these mice to TNF (Tumor Necrosis Factor) knock-out mice. Our findings suggest that TNF induced cell death, rather than TNF induced cytokine production, may be at the root of many inflammatory diseases and we aim to test this hypothesis in this proposal.Read moreRead less