Population Dynamics Of Tissue-specific Effector And Regulatory CD4+ T Cells
Funder
National Health and Medical Research Council
Funding Amount
$394,250.00
Summary
Survival of white blood cells in the body is an active process and is important for the maintainence of a T cell population which can recognise a wide variety of foreign antigens. At present the fate of T lymphocytes which recognise self antigens is unclear. Knowledge of the survival kinetics of self-reactive T lymphocytes and the mechanism by which they are regulated in the normal individual is crucial to be able to control the development of various diseases, including autoimmune diseases. Fro ....Survival of white blood cells in the body is an active process and is important for the maintainence of a T cell population which can recognise a wide variety of foreign antigens. At present the fate of T lymphocytes which recognise self antigens is unclear. Knowledge of the survival kinetics of self-reactive T lymphocytes and the mechanism by which they are regulated in the normal individual is crucial to be able to control the development of various diseases, including autoimmune diseases. From our previous studies of autoimmune gastritis we have generated cell lines of lymphocytes that recognise stomach-specific antigens and with these unique reagents we will perform experiments to determine the fate of these self-reactive T cells in a normal individual. Also we will determine the impact of different amounts of the tissue antigens on the survival and activation of self-reactive T cells, and finally how a special class of lymphocytes, know as regulatory lymphocytes, act in vivo to control the activity of self-reactive T cells. We will use not only classical immunological approaches to address these issues but also state of the art imaging, to visualise the nature of the cell interactions in living tissues. The information arising from this work will underpin strategies to selectively turn off self-reactive lymphocytes that cause disease, will form the basis of clinical development of cell based therapies to treat autoimmune diseases, and the imaging technologies developed in this grant will have wide applicability to the study of a range of immune responses.Read moreRead less
The Role Of Specific Nox Isoforms In Diabetic Renal Disease And Atherosclerosis
Funder
National Health and Medical Research Council
Funding Amount
$460,396.00
Summary
Diabetes is increasing worldwide and in Australia. The majority of patients with diabetes eventually will develop kidney disease and will die of blood vessel complications such as heart attacks and stroke. Oxidative stress (the generation of free oxygen radicals that react quickly with other proteins in the body causing tissue damage) has been suggested to play an important role in kidney and blood vessel disease observed in diabetic patients. This proposal will try to identify and measure speci ....Diabetes is increasing worldwide and in Australia. The majority of patients with diabetes eventually will develop kidney disease and will die of blood vessel complications such as heart attacks and stroke. Oxidative stress (the generation of free oxygen radicals that react quickly with other proteins in the body causing tissue damage) has been suggested to play an important role in kidney and blood vessel disease observed in diabetic patients. This proposal will try to identify and measure specific proteins in the kidney and vessels that are involved in the production of oxidative stress. We aim to define which one of these proteins is the most important. We will assess in detail how these proteins work and which other factors are activated leading to tissue damage. The ultimate goal of these studies is to find new treatment options to decrease the production of harmful molecules in the kidney and blood vessel wall thereby reducing kidney failure, heart attacks, stroke and gangrene in diabetes. In our studies, we will use medications already used in patients to treat high blood pressure in diabetes. In preliminary studies we have shown that these drugs also reduce oxidative stress. Furthermore, we will use novel, more specific treatments that the harmful ptoteins. Through a collaboration with Professor Harald Schmidt and his group from Germany who have recently moved to Monash University in Melbourne we will have access to mice in which specific genes for harmful proteins have been knocked out. These mice when made diabetic will most likely develop less or no kidney and blood vessel damage. Our studies will help to identify the most important oxidative stress producing protein associated with kidney and vessel disease. This knowledge will lead to more effective and more potent treatments for patients with diabetes to prevent, stop or even improve kidney and blood vessel disease thereby reducing disability and death in this high risk group of patients.Read moreRead less
Defining The Roles Of NADPH Oxidases In Vascular Remodelling And Arterial Hypertension
Funder
National Health and Medical Research Council
Funding Amount
$401,523.00
Summary
Hypertension (high blood pressure) is a major risk factor for cardiovascular diseases such as heart attacks, heart failure and stroke - the major causes of death world-wide and a huge burden on the Australian health care budget. Oxidative stress, resulting from an imbalance in the production and removal of toxic molecules called free radicals within the blood vessel wall, is a key player in the initiation and progression of these disorders. In the early stages of hypertension, production of free ....Hypertension (high blood pressure) is a major risk factor for cardiovascular diseases such as heart attacks, heart failure and stroke - the major causes of death world-wide and a huge burden on the Australian health care budget. Oxidative stress, resulting from an imbalance in the production and removal of toxic molecules called free radicals within the blood vessel wall, is a key player in the initiation and progression of these disorders. In the early stages of hypertension, production of free radicals only just outweighs their removal, resulting in a mild oxidative stress. However, this is enough to trigger a cascade of downstream events leading to activation of other, normally dormant, free radical generating systems. At these excessive levels, free radicals attack the cells of the artery wall leading to blood vessel dysfunction and ultimately cardiovascular disease. A major source of free radicals in the blood vessel wall are a family of enzymes called NADPH oxidases. It is our hypothesis that upregulation of onr of these enzymes in the early stages of hypertension is the initial trigger for many of the downstream effects that ultimately lead to cardiovascular disease. Our group is uniquely poised to test this hypothesis as we are the only laboratory in the world with access to three different strains of genetically modified mice, each lacking one of the three known isoforms of NADPH oxidase. Identification of the specific isoform of NADPH oxidase involved in free radical production in blood vessels is a critical first step in developing drugs that block vascular free radical production and so remove the molecular link between hypertension and major cardiovascular events.Read moreRead less
Mitochondrial Complex II Is A New Target For Anti-cancer Drugs
Funder
National Health and Medical Research Council
Funding Amount
$448,434.00
Summary
Cancer is a huge problem and is most likely to get worse. Therefore, new approaches to treatment are necessary. Cancer cells constantly mutate, so many established drugs cannot be used. A very promising approach is targeting mitochondria, the powerhouse of the cells. This is because these organelles are important for all cancer cells. We are proposing a novel way of using mitochondria as targets for a group of anti-cancer drugs that would ultimately result in efficient cancer management.
Formation of clots to prevent blood loss is initiated by the platelet receptors, glycoprotein (GP)Ib-IX-V and GPVI. Unfortunately, there is a gap in our knowledge regarding the events immediately following activation of these receptors and the known downstream signalling. We have identified a novel binding partner for these platelet receptors, which we believe links reactive oxygen species to platelet signalling events. This opens new avenues for therapies to prevent aberrant clotting.
Nitroso-redox Imbalance In Glucocorticoid-induced Hypertension
Funder
National Health and Medical Research Council
Funding Amount
$341,210.00
Summary
High blood pressure (hypertension) affects 20-30 % of Australian adults and in about 90-95 % of these individuals the hypertension is considered essential (cause unknown). Globally, it is the number 1 risk factor for death, and number 3 for disability (World Health Report 2002). The major consequences of hypertension are heart attack and stroke. Glucocorticoid (adrenal steroid hormone) induced hypertension and consequent cardiovascular morbidity-mortality is an important clinical problem. Althou ....High blood pressure (hypertension) affects 20-30 % of Australian adults and in about 90-95 % of these individuals the hypertension is considered essential (cause unknown). Globally, it is the number 1 risk factor for death, and number 3 for disability (World Health Report 2002). The major consequences of hypertension are heart attack and stroke. Glucocorticoid (adrenal steroid hormone) induced hypertension and consequent cardiovascular morbidity-mortality is an important clinical problem. Although naturally occurring glucocorticoid (GC) hypertension (Cushing's syndrome) is relatively rare, synthetic GC are widely used in clinical practice (in numerous inflammatory and autoimmune diseases and transplantation) and produce substantial cardiovascular morbidity and mortality. Further, abnormal GC breakdown (metabolism) and sensitivity to GC have been reported in around a third of essential hypertensive patients. We therefore need to understand how GC raise blood pressure and whether we can prevent and-or reverse these blood pressure raising effects. In the proposed studies, we will explore the role of relative deficiency of blood vessel dilating nitric oxide and nitric oxide inhibition by excess superoxide (nitroso-redox imbalance) in the genesis of GC hypertension. Further, we will identify agents known to be suitable for clinical use which are effective in preventing-reversing GC hypertension in the rat and are thus appropriate for clinical trials to prevent-reverse GC hypertension in humans. These studies will help answer the question of how GC raises blood pressure so that safer steroids can be designed, as well as identify agents that can potentially prevent or treat GC hypertension in humans.Read moreRead less
How Does Oxygen Regulate Ca2+ Channel Function In Cardiac Myocytes?
Funder
National Health and Medical Research Council
Funding Amount
$475,517.00
Summary
Oxygen occupies a key role in cellular metabolism and function. Oxygen delivery to cells is critical and lack of oxygen such as occurs during a heart attack can be lethal. Death occurs commonly by induction of arrhythmia or a disturbance in the heart beat. The abnormal heart beat cannot enable the heart to pump blood efficiently and vital organs are then deprived.Exactly how arrhythmia is induced is not understood. The normal heart beat occurs as a result of propogation of electrical signals thr ....Oxygen occupies a key role in cellular metabolism and function. Oxygen delivery to cells is critical and lack of oxygen such as occurs during a heart attack can be lethal. Death occurs commonly by induction of arrhythmia or a disturbance in the heart beat. The abnormal heart beat cannot enable the heart to pump blood efficiently and vital organs are then deprived.Exactly how arrhythmia is induced is not understood. The normal heart beat occurs as a result of propogation of electrical signals through heart muscle cells. The electrical activity is generated and sustained by movement of salts or ions through membrane proteins known as ion channels. One of these channels, the L-type calcium channel plays a vital role in cardiac excitation and contraction. A reduction in oxygen alters the function of the L-type calcium channel. However, the exact mechanism for this is uncertain. An oxygen sensing mechanism in the cell is responsible for the regulation of channel function during hypoxia. The exact identity of the oxygen sensor is currently the centre of debate. Four hypotheses have been proposed. This proposal aims to examine in detail the four hypotheses of oxygen sensing to definitively determine the identity of the oxygen sensor. This information should increase our understanding of how calcium channels function during stressful conditions such as during a heart attack.Read moreRead less