L-amino Acid Sensing By The Extracellular Calcium-sensing Receptor: Molecular, Cellular And In Vivo Studies
Funder
National Health and Medical Research Council
Funding Amount
$362,545.00
Summary
Recent work by Dr Conigrave and colleagues demonstrates for the first time that protein and calcium metabolism are linked at the molecular level by the widely distributed calcium-sensing receptor. The project will aim to demonstrate the physiological significance of this finding by testing whether L-amino acids, the building blocks of body protein, exert receptor-dependent control over the secretion and blood levels of hormones that regulate body calcium levels. It will further test the hypothes ....Recent work by Dr Conigrave and colleagues demonstrates for the first time that protein and calcium metabolism are linked at the molecular level by the widely distributed calcium-sensing receptor. The project will aim to demonstrate the physiological significance of this finding by testing whether L-amino acids, the building blocks of body protein, exert receptor-dependent control over the secretion and blood levels of hormones that regulate body calcium levels. It will further test the hypothesis by determining whether amino acids exert receptor-dependent control over the proliferation of bone forming cells and urinary excretion of calcium.Read moreRead less
Aldosterone Mediated Cardiac Pathophysiology:The Role Of Corticosteroid Receptors And 11 HSD Isoforms
Funder
National Health and Medical Research Council
Funding Amount
$481,500.00
Summary
Aldosterone a hormone that circulates in blood and is associated with cardiovascular disease. Recently, two clinical trials (RALES, EPHUSUS) demonstrate that if you stop this hormone from acting by giving drugs that inhibit it from binding to the receptor that mediates its response, there is an improvement in the health of heart failure patients. How aldosterone mediates its detrimental effects on heart is largely unknown. Glucocorticoids are another hormone that circulates in blood and can bind ....Aldosterone a hormone that circulates in blood and is associated with cardiovascular disease. Recently, two clinical trials (RALES, EPHUSUS) demonstrate that if you stop this hormone from acting by giving drugs that inhibit it from binding to the receptor that mediates its response, there is an improvement in the health of heart failure patients. How aldosterone mediates its detrimental effects on heart is largely unknown. Glucocorticoids are another hormone that circulates in blood and can bind to the same receptor as aldosterone. In contrast to aldosterone glucocorticoids appear to play a basic maintenance role in heart. Our central hypothesis is that in the healthy heart aldosterone has minimal effects , however, in the diseased heart aldosterone associated pathophysiology is a result of both an increase in the ability of aldosterone to signal to cells and disruption of glucocorticoid signalling. This grant proposal will address how aldosterone and glucocorticoids may directly signal within cardiac cells and how this signalling changes in the diseased heart. In addition, we investigate if enzymes that metabolize glucocortioids and thus render them non-functional play a role in cardiac disease, and if we can reverse the detrimental effects of aldosterone by artificially increasing the production of glucocorticoids in heart. By understanding the mechanisms by which aldosterone promotes cardiac disease, and the role of glucocorticoids and their metabolism in this process will lead to a better understanding of aldosterone induced pathology and thus lead to novel therapeutic targets.Read moreRead less
Mineralocorticoid Receptors - Mechanisms Of Ligand- And Tissue- Specific Activation
Funder
National Health and Medical Research Council
Funding Amount
$126,848.00
Summary
Heart disease is a major cause of death and economic burden in Australia and throughout the world. The steroid hormone aldosterone controls salt and water balance, blood pressure and has a significant role in heart failure. Although drugs that block the aldosterone receptor significantly help patients with heart failure, their use is limited by side effects. This work will identify the profile of proteins that promote aldosterone effects and enable the development of heart-specific blockers.
Novel Regulators Of Glucose Metabolism And Inflammation In Adipose Tissue Of Females
Funder
National Health and Medical Research Council
Funding Amount
$282,830.00
Summary
Obesity is a common problem which can lead to development of diabetes and heart disease. One of the major mechanisms by which obesity leads to these diseases involves a defect in the ability of insulin to stimulate uptake of glucose into cells. We have found that excess of the sex hormone testosterone in women can contribute to this defect in tissues. This study will investigate why testosterone causes this defect in females and whether this defect can be prevented using existing drug therapies.
Characterisation Of Alterations In The Androgen Signalling Axis That Contribute To Treatment Failure In Prostate Cancer
Funder
National Health and Medical Research Council
Funding Amount
$559,157.00
Summary
Prostate cancer is a major health problem in Western Countries including Australia, where it is the most common newly diagnosed invasive cancer and the second leading cause of cancer deaths in men. Although there have been improvements in the diagnosis of prostate cancer, many men are still diagnosed with disease that already has or will spread to other sites such as bone (ie metastatic disease). For those men with metastatic disease, reduction in testicular androgens by surgical or medical mean ....Prostate cancer is a major health problem in Western Countries including Australia, where it is the most common newly diagnosed invasive cancer and the second leading cause of cancer deaths in men. Although there have been improvements in the diagnosis of prostate cancer, many men are still diagnosed with disease that already has or will spread to other sites such as bone (ie metastatic disease). For those men with metastatic disease, reduction in testicular androgens by surgical or medical means (ie androgen ablation) is the only effective treatment option available. While androgen ablation is initially effective, treatment failure is common, resulting in a very poor overall survival rate. Evidence from our studies and others suggest that, the androgen receptor, which mediates the growth regulatory effects of androgens is often defective in prostate tumour cells. These altered or mutant receptors are activated inappropriately by other sex hormones such as estradiol and even agents used in the treatment of prostate cancer whereas the normal receptor is activated only by testicular androgens. This mechanism may explain why treatment fails in a subset of men with advanced prostate cancer. The major objective of our current studies is to define how these mutant androgen receptors cause treatment failure and facilitate prostate tumour growth. In addition, the current studies will evaluate a novel approach to treatment of prostate cancer which, based upon our preliminary results, has the potential to be effective even if alterations are present in the androgen receptor. The current studies therefore will provide a better understanding of factors controlling the growth of prostate tumours, and develop improved treatment approaches for advanced prostate cancer.Read moreRead less
Androgen Receptor Signalling And Progression Of Prostate Cancer
Funder
National Health and Medical Research Council
Funding Amount
$462,750.00
Summary
Prostate cancer is a major health problem in Australia, being the second leading cause of cancer deaths in men. Although there have been improvements in the diagnosis and treatment of prostate cancer, there are no effective treatments for advanced (metastatic) disease that has spread to other parts of the body. Currently, the only therapy for advanced disease involves the reduction in circulating androgens such as testosterone by surgical or medical castration, i.e. androgen ablation. Because pr ....Prostate cancer is a major health problem in Australia, being the second leading cause of cancer deaths in men. Although there have been improvements in the diagnosis and treatment of prostate cancer, there are no effective treatments for advanced (metastatic) disease that has spread to other parts of the body. Currently, the only therapy for advanced disease involves the reduction in circulating androgens such as testosterone by surgical or medical castration, i.e. androgen ablation. Because prostate cells are dependent on testicular androgens for their survival, surgical or medical castration results in an initial tumour regression. However, tumours inevitably develop resistance to current forms of androgen ablation therapy. Inappropriate activation of androgen signalling by non-testicular androgens or other agents may stimulate tumour growth following androgen ablation. In this study, we aim to identify and characterise determinants of the specificity and sensitivity of activation of the androgen receptor, which is the primary mediator of androgen action. Current androgen ablation treatments for prostate cancer only target the availability of androgenic ligands. We propose that it is also necessary to target the androgen receptor itself, because it can be activated by ligands other than testicular androgens. Therefore, we will also evaluate a panel ofagents that target different aspects of the androgen signalling axis, combined with androgen ablation using a cyclical approach to prevent or delay disease progression.Read moreRead less
Molecular Characterisation Of The Ligand-binding Domain Of The Mineralocorticoid Receptor
Funder
National Health and Medical Research Council
Funding Amount
$215,183.00
Summary
The steroid hormone aldosterone regulates blood pressure by controlling sodium retention. The important role of this hormone in blood pressure control is underlined by the fact that all known monogenetic hypertensive conditions involve aldosterone or sodium reabsorption. Aldosterone works by activating an intracellular 'receptor' protein that in turn switches on specific genes. The products of these genes act to produce sodium retention. Antagonists (blockers) of this receptor are used in the tr ....The steroid hormone aldosterone regulates blood pressure by controlling sodium retention. The important role of this hormone in blood pressure control is underlined by the fact that all known monogenetic hypertensive conditions involve aldosterone or sodium reabsorption. Aldosterone works by activating an intracellular 'receptor' protein that in turn switches on specific genes. The products of these genes act to produce sodium retention. Antagonists (blockers) of this receptor are used in the treatment of hypertension but have undesirable side effects. The design of new, more specific, antagonists has been slow because we do not understand how these drugs bind to the receptor and what effect they have on the protein. How the aldosterone receptor functions is poorly understood. This project aims to investigate the receptor in detail. We are in the process of determining regions of the receptor structure important for hormone binding. This information is vital for the design of new antagonists. The aldosterone receptor is unusual in that it is also activated by cortisol, a steroid hormone involved in stress and inflammation. By examining hormone binding it may be possible to determine if the two steroids activate the receptor in the same way. An understanding of how both natural hormones and synthetic antagonists function is impossible without thorough study of the receptor itself. We intend to examine fundamental aspects of aldosterone receptor function. In particular we wish to identify proteins that interact with the receptor. These proteins either enhance or inhibit the ability of the receptor to switch on genes and are vital to explaining the actions of both natural hormones and synthetic antagonists. Results from these experiments should advance our understanding of the basic biology of aldosterone action and its role in cardiovascular biology, and lead to the design of better receptor antagonists for use in the treatment of hypertension and cardiac fibrosis.Read moreRead less