Modulation Of Cell Phospholipids And Membranes By 7-ketocholesterol And Their Role In Cholesterol Efflux.
Funder
National Health and Medical Research Council
Funding Amount
$186,372.00
Summary
Atherosclerosis is a leading cause of death in Australia. The disease is caused by the formation of large deposits of cholesterol in the walls of major blood vessels. This cholesterol comes from cholesterol-carrying particles in the blood which penetrate into the tissue of the blood vessel. They are taken up by the cells of the tissue which become engorged with large amounts of cholesterol and are called 'foam cells'. These foam cells also contain a small but signficant amount of damaged (oxidis ....Atherosclerosis is a leading cause of death in Australia. The disease is caused by the formation of large deposits of cholesterol in the walls of major blood vessels. This cholesterol comes from cholesterol-carrying particles in the blood which penetrate into the tissue of the blood vessel. They are taken up by the cells of the tissue which become engorged with large amounts of cholesterol and are called 'foam cells'. These foam cells also contain a small but signficant amount of damaged (oxidised) forms of cholesterol, called oxysterols. We have found than an oxysterol called 7-ketocholesterol makes it difficult for cells to get rid of excess cholesterol. Therefore this oxysterol may be part of the reason why foam cells develop. This project will study how 7-ketocholesterol blocks cholesterol removal from cells. This may lead to the development of drugs which remove or prevent 7-ketcholesterol accumulation in the blood vessel and so prevent or reverse atherosclerosis.Read moreRead less
Ras Signalling And Cholesterol Efflux From Late Endosomes
Funder
National Health and Medical Research Council
Funding Amount
$276,598.00
Summary
Accumulation of cholesterol is a hallmark of early atherosclerotic lesions, known as foam cell formation. Hence the stimulation of cholesterol removal (efflux) from macrophages has great therapeutic potential. High Density Lipoproteins (HDL) and apolipoprotein A-I (apoA-I) stimulate efflux via activation of HDL-apoA-I receptors and poorly understood signalling pathways. This application is investigating the role of the Ras-MAPK signalling pathway in promoting efflux from late endosomes.
Atherosclerosis is the disease which narrows arteries and causes heart attacks and stroke. It is one of the major causes of death in Australia. Although certain treatments, such as lowering blood cholesterol levels, reduce the incidence of atherosclerosis, current motality rates from this disease indicate that there is still a great need to improve our understanding and treament of the condition. In the development of atherosclerosis, some of the cells in the vessel wall accumulate large deposit ....Atherosclerosis is the disease which narrows arteries and causes heart attacks and stroke. It is one of the major causes of death in Australia. Although certain treatments, such as lowering blood cholesterol levels, reduce the incidence of atherosclerosis, current motality rates from this disease indicate that there is still a great need to improve our understanding and treament of the condition. In the development of atherosclerosis, some of the cells in the vessel wall accumulate large deposits of cholesterol. These cells are macrophages, derived from circulating white blood cells that have migrated into the vessel wall. Normally these cells are able to efficiently export excess cholesterol, but this process seems to fail in atherosclerosis. This project will study the molecular mechanism for cholesterol export from macrophages, concentrating on a the mechnisms by which recently identified cholesterol pumps operate. These are located in cell membranes, including at the cell surface, which is the site at which cholesterol is transferred to acceptors such as HDL and apoAI. By understanding how these pumps work, and how their activities are controlled, we will be better able to devise ways to increase their efficiency in atherosclerosis, and so to prevent the tissue cholesterol accumulation that drives this disease.Read moreRead less
Functional Characterization Of Caveolae And Caveolins
Funder
National Health and Medical Research Council
Funding Amount
$140,660.00
Summary
This project aims to study the cellular machinery that allows a cell to respond to its external environment. Specifically, this project focusses on the function of a family of membrane proteins, called caveolins, which are the major protein components of caveolae small pits which cover the surface of many mammalian cells. Caveolins are believed to regulate signalling from the external environment to the cell interior and loss of this regulation leads to uncontrolled growth leading to cancer. Sig ....This project aims to study the cellular machinery that allows a cell to respond to its external environment. Specifically, this project focusses on the function of a family of membrane proteins, called caveolins, which are the major protein components of caveolae small pits which cover the surface of many mammalian cells. Caveolins are believed to regulate signalling from the external environment to the cell interior and loss of this regulation leads to uncontrolled growth leading to cancer. Signalling from the cell surface relies on organisation of signalling components into modules. Our studies suggest that these modules are dependent on specific lipid molecules which form discrete patches, called lipid rafts, on the cell surface. We have hypothesised that caveolins control the lipid molecules associated with lipid rafts and so, indirectly, control signalling pathways. In particular, we have shown that caveolin is important in the regulation of cellular cholesterol, a vital molecule involved in maintaining the function of lipid raft domains. As numerous human diseases are associated with cholesterol imbalance, studies of caveolins can give fundamental new insights into this process, and the previously unidentified links between the cellular lipid balance and signal transduction. This project aims to use mutant caveolin molecules to disrupt caveolin function and so determine the role of caveolin in lipid regulation and in signal transduction. We will then use a lower vertebrate model system, which is amenable to experimental manipulation, to determine the role of caveolins and rafts in the development of the whole embryo.Read moreRead less
Characterising An Important Control Point In Cholesterol Synthesis Beyond HMG-CoA Reductase
Funder
National Health and Medical Research Council
Funding Amount
$480,739.00
Summary
The statins are the ‘go-to’ drugs for treating heart disease; blocking a very early, highly-controlled step in the pathway producing cholesterol. However, they inhibit the production of other vital molecules which explains why some patients do not tolerate them. We have identified that a later enzyme in this pathway is also highly controlled and here aim to characterise the molecular mechanisms involved. This work could translate into the development of even safer drugs for treating cholesterol- ....The statins are the ‘go-to’ drugs for treating heart disease; blocking a very early, highly-controlled step in the pathway producing cholesterol. However, they inhibit the production of other vital molecules which explains why some patients do not tolerate them. We have identified that a later enzyme in this pathway is also highly controlled and here aim to characterise the molecular mechanisms involved. This work could translate into the development of even safer drugs for treating cholesterol-related diseases.Read moreRead less
The Role Of The ABCA12 Transporter In Epidermal Lipid Homeostasis And Atherosclerosis
Funder
National Health and Medical Research Council
Funding Amount
$516,401.00
Summary
We have shown that a protein called Abca12 can control the transport of lipids in our bodies. If the function of this gene is attenuated both human and mice develop severe skin disease. Our preliminary results indicate the Abca12 protein regulates cholesterol transport in particular, and this grant will investigate how this might affect normal skin function and contribute to the heart disease atherosclerosis, one of the most common causes of death in the western world.
Our goal is to discover new mechanisms involved in our cells’ delicate balancing act with respect to cholesterol levels. Understanding how production of cholesterol is controlled in our cells is key to developing new drugs aimed at preventing its excessive accumulation. This will have long-term benefits for health considering that a cellular imbalance in cholesterol is involved in two of the most common conditions threatening the health of Australians, namely heart disease and Alzheimer’s diseas ....Our goal is to discover new mechanisms involved in our cells’ delicate balancing act with respect to cholesterol levels. Understanding how production of cholesterol is controlled in our cells is key to developing new drugs aimed at preventing its excessive accumulation. This will have long-term benefits for health considering that a cellular imbalance in cholesterol is involved in two of the most common conditions threatening the health of Australians, namely heart disease and Alzheimer’s disease.Read moreRead less