Oxidation Of Arterial Extracellular Matrix By Myeloperoxidase-derived Oxidants
Funder
National Health and Medical Research Council
Funding Amount
$183,266.00
Summary
It is well established that changes occur in the composition and nature of the extracellular matrix present in the artery wall during the development of atherosclerosis. The changes that occur in this matrix affect both the mechanical and physical properties of the arterial wall (e.g. its ability to cope with the high pressures genrated by the pumping of blood from the heart) and the adhesion of cells. It is well established that certain key cell types do not adhere well, or grow properly, on al ....It is well established that changes occur in the composition and nature of the extracellular matrix present in the artery wall during the development of atherosclerosis. The changes that occur in this matrix affect both the mechanical and physical properties of the arterial wall (e.g. its ability to cope with the high pressures genrated by the pumping of blood from the heart) and the adhesion of cells. It is well established that certain key cell types do not adhere well, or grow properly, on altered or damaged matrix and this can result in either the loss of key cell types from the artery wall (e.g. loss of endothelial cells) and - or the proliferation and invasion of cells from other sources (e.g. smooth muscle cell invasion into the intimal space). There is circumstantial evidence that some of these changes occur via the formation of oxidants by the heme enzyme myeloperoxidase which is released from activated white cells. In this study we will employ recently developed analytical techniques to examine the nature of the alterations that are present in atherosclerotic plaques in comparison to normal human artery samples, and investigate the mechanisms by which such alterations arise. We will seek evidence for, or against, the involvement of myeloperoxidase-derived oxidants in the observed changes using specific markers which we have developed for the presence of such damage. This information will allow the rational design of strategies to interfere with the progression of atherosclerosis, which is the major killer of Australians.Read moreRead less
Molecular Mechanisms Of Disease In The Collagen VI-related Muscular Dystrophies
Funder
National Health and Medical Research Council
Funding Amount
$519,715.00
Summary
The inherited muscular dystrophies are an important cause of disability in Australia. This project concentrates on the second most common group of congenital muscular dystrophies - those caused by mutations in collagen VI and its interacting partners. We will determine how mutations affect the structure of the protein and how the muscle is disrupted by the mutations. This work will open the way for research into potential therapies. We will also find new genes that cause muscular dystrophy.
The Role Of Tissue Factor In The Regulation Of Extracellular Matrix Remodelling And Angiogenesis.
Funder
National Health and Medical Research Council
Funding Amount
$241,980.00
Summary
The aim of the project is to understand how some blood clotting factors may be involved with the regulation of the extracellullar matrix (the material that exists between cells) and angiogenesis (new blood vessel formation). New blood vessel growth occurs in a wide variety of situations including: healing of a flesh wound, the healing phase following a heart attack, development of the eye disease associated with sugar diabetes, in and around a cancerous growth, in the uterus during the normal me ....The aim of the project is to understand how some blood clotting factors may be involved with the regulation of the extracellullar matrix (the material that exists between cells) and angiogenesis (new blood vessel formation). New blood vessel growth occurs in a wide variety of situations including: healing of a flesh wound, the healing phase following a heart attack, development of the eye disease associated with sugar diabetes, in and around a cancerous growth, in the uterus during the normal menstrual cycle, and for the normal growth and development of the placenta and a new baby. The processes by which these new blood vessels form and the factors contributing to the maintenance of their structure are incompletely understood. However, it is known that the interaction of cells and the surrounding extracellular matrix is critical for normal cell function and in particular for new blood vessel formation. Studies in this project will seek to define a relationship between some of the factors which regulate blood clotting, and those that regulate turnover of the extracellular matrix and new blood vessel formation. In particular, how blood clotting factors may be invovled in the regulation of the extracellular matrix will be studied in a rapidly developing tissue, the mouse placenta. The role of blood clotting factors in regulation of new blood vessel formation into an artificial avascular tissue will also be examined. These studies will employ some of the new genetic techniques to understand new roles for proteins which have been traditionally thought to act in only one way. This research has the potential to provide new insights into how blood vessels are formed and are subsequently maintained. This increased understanding will provide the knowledge required for the development of new therapeutic strategies to correct the process when it goes wrong, is unwanted or underdeveloped in human disease.Read moreRead less
KIT As A Target For The Modification Of Vascular Proteoglycans And Prevention Of Atherosclerosis
Funder
National Health and Medical Research Council
Funding Amount
$342,864.00
Summary
Heart disease occurs when arteries supplying blood to the heart become blocked. One aspect of this blockage is the capture of fats from the blood, by artery wall structures called proteoglycans. Proteoglycans are made up of a core protein and sugar chains (GAGs). The stickier the GAGs, the more fats that are captured. No drug treatment acts directly on the artery wall to prevent heart disease. This project aims to identify steps that lead to stickier GAGs and therefore a potential drug target.
Damage To Arterial Extracellular Matrix Induced By Reactive Nitrogen Species And Its Consequences
Funder
National Health and Medical Research Council
Funding Amount
$326,250.00
Summary
It is well established that lipids accumulate in the artery wall during the development of atherosclerosis (hardening of the arteries), and that much of this lipid arises from low-density lipoproteins (LDL). The uptake of cholesterol and lipids from LDL by cells present in the arterial wall is normally tightly regulated and under feedback control, but modification of the LDL particles can result in their recognition by the scavenger receptors of macrophage cells and unregulated accumulation of l ....It is well established that lipids accumulate in the artery wall during the development of atherosclerosis (hardening of the arteries), and that much of this lipid arises from low-density lipoproteins (LDL). The uptake of cholesterol and lipids from LDL by cells present in the arterial wall is normally tightly regulated and under feedback control, but modification of the LDL particles can result in their recognition by the scavenger receptors of macrophage cells and unregulated accumulation of lipids within such cells. The formation of these lipid-laden (foam) cells is a hallmark of atherosclerosis. Whilst this lipid accumulation is undesirable, if the resulting lesions are stable they are of less concern than those that are unstable and prone to rupture. Rupture of lesions and consequent blood clot formation (thrombosis) are a prime cause of sudden heart death and stroke. Despite considerable effort the reasons for plaque rupture are poorly understood. This study will investigate one potential mechanism by which lesions might become destabilised and prone to rupture. We will investigate the role of reactive intermediates in inducing damage to the extracellular matrix. Reactive intermediates are known to be generated by inflammatory cells, and it is well established that these cells are present at elevated levels in lesions. The extracellular matrix is responsible for maintaining the 3-dimensional structure of biological systems including the artery wall, and damage or fragmentation of this material may weaken this scaffolding and make the lesions prone to rupture. We will also examine how such matrix damage affects the behaviour of cells within lesions. A detailed knowledge of which processes are important in lesion rupture is an essential prerequisite to the development of new therapeutic strategies.Read moreRead less
Myeloperoxidase-catalysed Damage To Arterial Extracellular Matrix And Its Consequences
Funder
National Health and Medical Research Council
Funding Amount
$384,750.00
Summary
A heme enzyme (myeloperoxidase) has been shown to be present in the lesions present in diseased human arteries, and it has been reported that this enzyme contributes to the development of arterial disease via its ability to catalyse the formation of highly reactive oxidants. Recent studies have shown that the level of this enzyme correlate strongly with the presence of coronary artery disease, and that this enzyme may play a role in plaque rupture, a leading cause of sudden coronary death. It ha ....A heme enzyme (myeloperoxidase) has been shown to be present in the lesions present in diseased human arteries, and it has been reported that this enzyme contributes to the development of arterial disease via its ability to catalyse the formation of highly reactive oxidants. Recent studies have shown that the level of this enzyme correlate strongly with the presence of coronary artery disease, and that this enzyme may play a role in plaque rupture, a leading cause of sudden coronary death. It has also been reported that elevated levels of metal ions are present in advanced human atherosclerotic lesions. In recent experiments we have shown that products generated by myeloperoxidase can interact with metal ions and superoxide radicals, and that this process results in an exacerbation of damage. This synergism between the oxidants generated by myeloperoxidase and metal ions may explain, at least in part, the complex mixture of products detected in human lesions and be responsible for the weakening of lesion structure and contribute to an enhanced likelihood of plaque rupture. This study will examine the potential effects and mechanisms of damage to extracellular matrix materials from normal arteries and cultured cells We will examine under what circumstances interactions occur and whether these reactions may play a key role in plaque rupture. We will also examine how materials arising from damage to the extracellular matrix may affect the cells whic grow upon this scaffolding, and whether this may be partly responsible for altered behaviour of cells within dveloping atherosclerotic lesions. A detailed knowledge of which processes are important in plaque rupture is an essential pre-requisite to the development of new therapeutic strategies.Read moreRead less