Cytokine Secretion: A Model For Protein Trafficking.
Funder
National Health and Medical Research Council
Funding Amount
$204,111.00
Summary
TNF-a is an inflammatory cytokine with important roles in host defense, tumour regulation and energy homeostatis, however the oversecretion of TNF-a is also a major cause of septic shock, rheumatoid arthritis, Chron?s disease and the cachexia of cancer. TNF-a synthesis and its release from the surface of cells are relatively well understood. However little is known about its trafficking through the secretory pathway of cells. Understanding this process has the potential to provide new ways of co ....TNF-a is an inflammatory cytokine with important roles in host defense, tumour regulation and energy homeostatis, however the oversecretion of TNF-a is also a major cause of septic shock, rheumatoid arthritis, Chron?s disease and the cachexia of cancer. TNF-a synthesis and its release from the surface of cells are relatively well understood. However little is known about its trafficking through the secretory pathway of cells. Understanding this process has the potential to provide new ways of controlling the secretion of TNF-a. In previous work we have characterized transport vesicles and cytoskeletal proteins involved in secretory pathways of epithelial cells. We now propose to focus on the characterization of transport vesicles, and the roles of actin and myosins involved in TNF-a secretion in macrophages. These studies will rely on introducing new technology to this line of research. Fluorescent tagged constructs of TNF-a will be expressed and viewed in living cells to analyse the secretory pathway and measure the transport of TNF-a from its site of accumulation in the Golgi complex to the cell surface. This work aims to identify membrane-bound vesicles and vesicle-associated proteins that target TNF-a for secretion. We will begin to investigate the role of actin and myosins, using drugs and microinjected peptides to block their function. Overall these studies will provide important cell biological information about protein trafficking in cells. Cytokine secretion is important in immunity and cancer, information important to both fields will be gained from these studies.Read moreRead less
Regulators Of G Protein Signalling On The Golgi Complex
Funder
National Health and Medical Research Council
Funding Amount
$666,116.00
Summary
The secretion of proteins from cells involves a host of regulatory and signalling proteins. G proteins, signal transducers, located on the Golgi membranes, participate in the budding of transport vesicles in the secretory pathway. A newly-discovered family of Regulators of G Protein Signalling (RGS) proteins perform the critical function of turning off signals generated by G proteins. RGS proteins are powerful, but as yet, ill-defined regulatory molecules. In this study we will identify and char ....The secretion of proteins from cells involves a host of regulatory and signalling proteins. G proteins, signal transducers, located on the Golgi membranes, participate in the budding of transport vesicles in the secretory pathway. A newly-discovered family of Regulators of G Protein Signalling (RGS) proteins perform the critical function of turning off signals generated by G proteins. RGS proteins are powerful, but as yet, ill-defined regulatory molecules. In this study we will identify and characterize RGS proteins in macrophages that are located on Golgi membranes and help to regulate cytokine secretion and other immune functions. More detailed studies on selected RGS proteins will include mutational analysis of functional domains within the proteins and identification of other proteins that interact with RGS proteins. Overall these studies will lead us to understand how specific RGS proteins interact with G proteins and other molecules to regulate signalling in the secretory pathway. Anomalies in cell signalling have severe consequences in a variety of diseases and can cause cancer. Similarly, abnormal secretion in cells contributes to inflammation, diabetes and other disease processes. Information forthcoming from our studies on RGS proteins will have wide-reaching implications and the potential to reveal new targets for therapeutics in these diseases.Read moreRead less
Investigating The Physiological And Biochemical Role Of SOCS5 In The Immune System
Funder
National Health and Medical Research Council
Funding Amount
$405,940.00
Summary
Asthma affects millions of people worldwide and is a complex inflammatory disease of the lung. Asthma manifests as recurrent episodes of wheezing, breathlessness, chest tightening, and coughing. Three key proteins called; interleukin 4 (IL-4), interleukin 13 (IL-13) and interleukin 5 (IL-5) are produced by a subset of white blood cells (T helper cells; Th2) and are thought to be responsible for the asthma response. Normally these proteins act to coordinate the body s immune defence against paras ....Asthma affects millions of people worldwide and is a complex inflammatory disease of the lung. Asthma manifests as recurrent episodes of wheezing, breathlessness, chest tightening, and coughing. Three key proteins called; interleukin 4 (IL-4), interleukin 13 (IL-13) and interleukin 5 (IL-5) are produced by a subset of white blood cells (T helper cells; Th2) and are thought to be responsible for the asthma response. Normally these proteins act to coordinate the body s immune defence against parasite infection. In other words, asthma is thought to arise through inappropriate IL-4 and IL-13 activity in the absence of a parasite infection. Extra IL-13 is commonly found in the lungs of asthmatics and is thought to help trigger asthma attacks. IL-13 is a validated target for drugs that could be used in the treatment of asthma. The SOCS genes were discovered in our laboratory and by genetically deleting the genes in mice we have demonstrated a critical role for SOCS1, SOCS2 and SOCS3 in regulating the immune response and the action of growth hormone. My hypothesis is that SOCS5 is an important physiologic regulator of the asthma response. This proposal will investigate the basic biochemical processes underlying the regulation of IL-4 and IL-13 action and the relationship to development of asthma and immune disease. I plan to induce asthma attacks in mice that lack the genes for SOCS4 and SOCS5. If the severity of the attacks is greater in the absence of these proteins this will indicate that SOCS4 and-or SOCS5 are important negative regulators of IL-4 and IL-13. This has the potential to open up a completely new strategy for the development of drugs that could be used in the prevention and treatment of asthma.Read moreRead less
Sorting Nexins And Their Role In Endosomal Trafficking
Funder
National Health and Medical Research Council
Funding Amount
$331,000.00
Summary
Cells are able to internalise molecules via membrane-bound vesicles, a process known as endocytosis. Endocytosis is fundamental for many cellular processes, including receptor signalling, uptake of many essential nutrients and the ability to mount an effective lymphocyte response to foreign antigens. Once internalised, cargo is then sorted to different intracellular destinations of the endosomal transport system. The ultimate destination depends on the particular cargo molecule. The importance o ....Cells are able to internalise molecules via membrane-bound vesicles, a process known as endocytosis. Endocytosis is fundamental for many cellular processes, including receptor signalling, uptake of many essential nutrients and the ability to mount an effective lymphocyte response to foreign antigens. Once internalised, cargo is then sorted to different intracellular destinations of the endosomal transport system. The ultimate destination depends on the particular cargo molecule. The importance of the endosomal transport system is also highlighted by the discovery that many human diseases, including various cancers, lysosomal storage diseases and hypercholesterolemia, are linked to defects in trafficking along the endocytic pathway. Furthermore, a number of viral pathogens, such as HIV, and toxins, such as shiga toxin, exploit the endosomal system to gain entry into a cell. Understanding the molecular details of the sorting events within the endosomal system is necessary to be able to consider therapeutic manipulation of the trafficking of specific cargo molecules. The study seeks to understand the molecular details of the endosomal sorting machinery, knowledge that will underpin future efforts to develop drugs to manipulate movement of proteins within the endosomal system. In the long term, this could allow for the manipulation of a variety of cellular functions including the inhibition of proliferative signals in tumour cells.Read moreRead less
The molecular basis of macropinocytosis in mammalian cells: the composition of endosome proteins and their function. Individual cells communicate with their immediate environment by the process of macropinocytosis, a process that involves the exchange of materials between the extracellular space and a specialised region of the cell termed endosomes. It is an important process in mammalian cells being essential to the correct functioning of many tissues. This project will advance understanding of ....The molecular basis of macropinocytosis in mammalian cells: the composition of endosome proteins and their function. Individual cells communicate with their immediate environment by the process of macropinocytosis, a process that involves the exchange of materials between the extracellular space and a specialised region of the cell termed endosomes. It is an important process in mammalian cells being essential to the correct functioning of many tissues. This project will advance understanding of macropinocytosis at a molecular level. The project is relevant to understanding the functioning of normal cells and the means by which some pathogens can enter cells and also understanding processes involved in tumour progression and metastasis.Read moreRead less
Determination of the mechanisms of immune system regulation of inflammation by the human protein, chaperonin 10. The aim of this project is to determine the mechanisms by which a human protein, chaperonin 10 (Cpn10), regulates the immune system and suppresses inflammation. When cells of the human immune system are challenged with lipopolysaccharide (LPS) (a product of bacterial infection), the pro-inflammatory cytokine TNF is released. Cpn10 has been shown to suppress production of TNF on chall ....Determination of the mechanisms of immune system regulation of inflammation by the human protein, chaperonin 10. The aim of this project is to determine the mechanisms by which a human protein, chaperonin 10 (Cpn10), regulates the immune system and suppresses inflammation. When cells of the human immune system are challenged with lipopolysaccharide (LPS) (a product of bacterial infection), the pro-inflammatory cytokine TNF is released. Cpn10 has been shown to suppress production of TNF on challenge of cells with LPS, while increasing the levels of the anti-inflammatory cytokine IL-10. Investigating the role of Cpn10 in modulating inflammation will contribute to the understanding and treatment of diseases associated with inflammation, including multiple sclerosis and rheumatoid arthritis.Read moreRead less
The development of tyrosine kinase inhibitors for the treatment of inflammation and malignant disease. Through the combination of expertise from the Industry partner and the Hume group this project aims to develop specific inhibitors of the CSF-1 receptor protein tyrosine kinase in order to demonstrate their efficacy as modulators of CSF-1 dependent macrophage and tumour cell function in vitro. The expected outcome will be a lead set of targets which can be further assessed for therapeutic pote ....The development of tyrosine kinase inhibitors for the treatment of inflammation and malignant disease. Through the combination of expertise from the Industry partner and the Hume group this project aims to develop specific inhibitors of the CSF-1 receptor protein tyrosine kinase in order to demonstrate their efficacy as modulators of CSF-1 dependent macrophage and tumour cell function in vitro. The expected outcome will be a lead set of targets which can be further assessed for therapeutic potential in clinical trials.Read moreRead less
Investigation of the fundamental roles of class Ib MHC (major histocompatibility complex) molecules in immunity. The proposed research program, using laboratory-based and synchrotron-based radiation, will provide insight into the roles of a poorly understood class of immune molecules. This will improve our understanding of the regulation of immunity, and the knowledge gained will increase Australia's international research profile.