MECHANISMS OF CEREBROVASCULAR REGULATION IN HEALTH AND DISEASE
Funder
National Health and Medical Research Council
Funding Amount
$216,430.00
Summary
Failure of the cerebral circulation to meet the brain's immediate high nutritive requirements results in stroke in just a few minutes. Stroke continues to be a major cause of death and disability, and this major medical challenge requires urgent and significant research at the basic level to better understand mechanisms of normal, and then abnormal, regulation of cerebral artery function. The project will examine the importance of a novel mechanism in regulating brain blood flow by affecting the ....Failure of the cerebral circulation to meet the brain's immediate high nutritive requirements results in stroke in just a few minutes. Stroke continues to be a major cause of death and disability, and this major medical challenge requires urgent and significant research at the basic level to better understand mechanisms of normal, and then abnormal, regulation of cerebral artery function. The project will examine the importance of a novel mechanism in regulating brain blood flow by affecting the degree of opening of the cerebral arteries. This mechanism involves activation of an enzyme, Rho-kinase, which is present in the wall of blood vessels. The applicants believe that this process plays an important role in the normal, healthy regulation of blood supply to the brain. Moreover, there are strong reasons for us to speculate that the function of this enzyme is abnormally high in two disease states that are associated with an increased risk of stroke - high blood pressure and subarachnoid haemorrhage. We will employ a variety of techniques to assess the importance of Rho-kinase in cerebral artery function in the living body, and also in isolated segments of artery. The results are expected to provide major new insight into mechanisms that regulate brain blood flow, and the knowledge gained here may lead to better therapies to prevent or treat stroke.Read moreRead less
Molecular Interactions Of Novel Conotoxin Inhibitors Of The Noradrenaline Transporter
Funder
National Health and Medical Research Council
Funding Amount
$392,036.00
Summary
A novel class of conotoxins (chi-conotoxins) has been discovered in the venom of an Australian cone snails, Conus marmoreus. Chi-conotoxins are the first peptide inhibitors of the noradrenaline transporter. From binding studies, it appears they act at a new site, remote from the site of action of antidepressants. This project is aimed at understanding how and where this novel class of peptide binds to the transporter. The results of this study are designed to maximise the potential of these pate ....A novel class of conotoxins (chi-conotoxins) has been discovered in the venom of an Australian cone snails, Conus marmoreus. Chi-conotoxins are the first peptide inhibitors of the noradrenaline transporter. From binding studies, it appears they act at a new site, remote from the site of action of antidepressants. This project is aimed at understanding how and where this novel class of peptide binds to the transporter. The results of this study are designed to maximise the potential of these patented peptides to be used as leads to the development of a new class of therapeutic for controlling the adverse effects of inadequate noradrenaline balance.Read moreRead less
Heme-oxidised Soluble Guanylyl Cyclase, A Mechanism-based Target For Vascular Diagnostics And Vasoprotective Therapy
Funder
National Health and Medical Research Council
Funding Amount
$524,456.00
Summary
Nitric oxide is produced in the inner lining of blood vessels and maintains blood flow via binding to a specific protein, sGC. In disease, sGC is defective and can be targeted by a novel group of drugs which are more active in diseased versus normal blood vessels. This project will examine the use of these drugs as markers of cardiovascular disease and in the treatment of high cholesterol and may lead to the development of new diagnostic tools and therapies for vascular complications.
Novel G-protein Coupled Receptors LGR7 And LGR8; The Receptors For Relaxin And Insulin-like Peptide 3 (INSL3)
Funder
National Health and Medical Research Council
Funding Amount
$496,500.00
Summary
Relaxin is a hormone which has long been known to have essential roles in pregnancy and birth. However it has also been demonstrated to have far broader involvement in the functioning of the kidney, heart and central nervous system. Furthermore, mice lacking relaxin show increased collagen, or fibrosis, in their internal organs and skin as they age. This progressive fibrosis leads to problems with bodily functions. Treatment of these mice with relaxin reverses the fibrosis and restores function, ....Relaxin is a hormone which has long been known to have essential roles in pregnancy and birth. However it has also been demonstrated to have far broader involvement in the functioning of the kidney, heart and central nervous system. Furthermore, mice lacking relaxin show increased collagen, or fibrosis, in their internal organs and skin as they age. This progressive fibrosis leads to problems with bodily functions. Treatment of these mice with relaxin reverses the fibrosis and restores function, hence relaxin has great potential as a treatment for fibrotic diseases. Anti-fibrotic drugs are a major target for drug companies as suitable compounds are not currently available. Research into the mechanisms whereby relaxin exerts its cellular effects has been limited by the inability of researchers to identify its receptor. We now know that relaxin acts through a novel G-protein coupled receptor (GPCR) LGR7 and will also act on a related receptor LGR8. The LGR8 receptor is actually the receptor for a hormone with similarities to relaxin, INSL3. It is essential that an appreciation of relaxin receptor function is obtained not only for its important actions in pregnancy, but also for its clinical applications. In this regard, improved understanding of how relaxin interacts with these two receptors is essential. We will use our expertise in producing these hormones together with molecular techniques to produce the receptor, to study the interaction of relaxin and INSL3 with these receptors and the subsequent cellular events that occur. Furthermore, to more effectively use relaxin as a drug, we need to discover a smaller, more potent and orally active form of the hormone. We will develop novel technologies to aid in the discovery of the next generation of relaxin drugs. This multi-disciplinary approach will allow us to fully maximise the clinical potential of this enigmatic hormone.Read moreRead less
Molecular Attributes And Physiological Significance Of Beta1L-adrenoceptors
Funder
National Health and Medical Research Council
Funding Amount
$754,353.00
Summary
Beta-blockers are used for the management of cardiovascular diseases including heart failure. We have discovered that one group of beta-blockers not only blocks the receptor but stimulates it. To explain this we hypothesize that human beta-adrenoceptors exist in two different 'states' , high and low. We are now determining whether 1. the low state causes progression of heart failure, 2. the molecular basis of the two states and 3. we can make new compounds to block the low state.
Actions Of Vanilloids In The Nucleus Of The Solitary Tract
Funder
National Health and Medical Research Council
Funding Amount
$196,527.00
Summary
Capsaicin, the active ingredient of hot chillies, and other pungent plant extracts have been used for millennia to relieve minor pain. We now know that these agents produce pain relief (analgesia) by numbing the very nerve cells (neurons) which transmit pain signals to the brain. The unique analgesic properties of vanilloids may have a place in modern medicine, giving relief to sufferers of certain types of chronic pain (e.g., neuropathic pain) which are not responsive to morphine-like analgesic ....Capsaicin, the active ingredient of hot chillies, and other pungent plant extracts have been used for millennia to relieve minor pain. We now know that these agents produce pain relief (analgesia) by numbing the very nerve cells (neurons) which transmit pain signals to the brain. The unique analgesic properties of vanilloids may have a place in modern medicine, giving relief to sufferers of certain types of chronic pain (e.g., neuropathic pain) which are not responsive to morphine-like analgesics. Indeed, the promise of more potent and less pungent vanilloid analgesics has led to the discovery of numerous naturally-occurring and synthetic vanilloids. However, although the neurons which convey information regarding blood pressure and the oxygen content of arterial blood to control centres in the brain stem are also stimulated by vanilloids, the central (brain stem) actions of vanilloids on blood pressure and respiration have not been investigated in detail. Thus, the aim of this project is to describe the characteristics of vanilloid receptors in the brain stem, determine the acute and chronic effects of naturally-occurring and synthetic vanilloids on blood pressure and respiration, and elucidate the role played by other neurotransmitter chemicals in the actions of vanilloids. The results of these studies will have major implications in the future use of vanilloids as analgesics.Read moreRead less
Mechanisms Of Protease-activated Receptor-2-mediated Bronchoprotection
Funder
National Health and Medical Research Council
Funding Amount
$354,758.00
Summary
The incidence of asthma continues to increase globally, yet there have been few real therapeutic advances. Our research, however, has recently uncovered a novel mechanism that protects the airways from inflammatory diseases like asthma. We have found that the layer of cells that line the airways - the epithelium - acts as a detector of early inflammatory events and releases anti-inflammatory substances. The lungs achieve this level of protection via 'sensor' molecules called receptors which are ....The incidence of asthma continues to increase globally, yet there have been few real therapeutic advances. Our research, however, has recently uncovered a novel mechanism that protects the airways from inflammatory diseases like asthma. We have found that the layer of cells that line the airways - the epithelium - acts as a detector of early inflammatory events and releases anti-inflammatory substances. The lungs achieve this level of protection via 'sensor' molecules called receptors which are located in the epithelium. In the case of our discovery, these receptors are called protease-activated receptors (PARs) to highlight the unique manner in which they are turned on or activated by enzymes called proteases. We have discovered that the epithelium of the lungs stores these enzymes and probably releases them during the inital stages of infection. Once released, these enzymes are detected by PARs on epithelial cells which then release substances that inhibit multiple inflammatory pathways. This mechanism protects the airways from effects that make breathing difficult, as in asthma. We have confirmed that this system provides protection in the airways of intact animals. The purpose of this projects outlined in this application is to examine the effects of activating one PAR, PAR2, on several processes in the lung, in order to characterise the individual events and processes that underlie the protective response. These studies will enable us to determine whether synthetic compounds that activate PAR2 are potential novel compounds for the treatment of diseases like asthma.Read moreRead less
Urotensin-II In Human Heart: Investigation Of Mechanisms Involved In Cardiac Function
Funder
National Health and Medical Research Council
Funding Amount
$255,990.00
Summary
The normal function of the body is maintained by naturally occurring compounds. Some for example affect the heart, fine tuning it to make it beat faster or slower, or beat with greater or less force when required in different situations in health and disease. We were the first to show just recently that a small protein which occurs naturally in the body, called urotensin-II can affect the way the heart beats. We showed that extremely tiny amounts increase the force of the heart beat. Our finding ....The normal function of the body is maintained by naturally occurring compounds. Some for example affect the heart, fine tuning it to make it beat faster or slower, or beat with greater or less force when required in different situations in health and disease. We were the first to show just recently that a small protein which occurs naturally in the body, called urotensin-II can affect the way the heart beats. We showed that extremely tiny amounts increase the force of the heart beat. Our findings indicate that urotensin-II is the most potent heart stimulator identified to date. In patients with heart failure, short term stimulation of heart contraction is beneficial, supplying the heart and other organs with vital oxygen and nutrients. However, in the long term excessive stimulation causes worsening of the patients condition. Very little is currently known about the way in which urotensin-II alters heart function. The goal of our study is to understand the mechanism involved in urotensin-II mediated effects on the heart. This will involve identifying the location of urotensin-II and its receptors in the heart, and determining what signalling changes occur after the interaction of urotensin-II with its receptors. Urotensin-II must first be cleaved from a larger drug. We will determine where in the heart this cleavage occurs and whether the process is crucial to the ability of urotensin-II to stimulate contraction of the heart. Since stimulators of heart contraction are detrimental to patients with heart failure in the long term, we will determine whether these patients have more urotensin-II in their blood than patients who do not have heart failure. If the levels of urotensin-II are higher in heart failure patients, it may indicate a need to interfere with the interaction of urotensin-II with its receptors.Read moreRead less
Our bodies generate a hormone called angiotensin II in response to a decrease in blood pressure (or salt in our bloodstream). This hormone increases blood pressure by causing blood vessels to constrict, by making us thirsty, and by inducing salt and fluid retention via an effect on the kidneys. In some cardiovascular diseases, the generation of angiotensin II or our sensitivity to this hormone is elevated. It is therefore crucial that we understand how angiotensin II works and how its actions in ....Our bodies generate a hormone called angiotensin II in response to a decrease in blood pressure (or salt in our bloodstream). This hormone increases blood pressure by causing blood vessels to constrict, by making us thirsty, and by inducing salt and fluid retention via an effect on the kidneys. In some cardiovascular diseases, the generation of angiotensin II or our sensitivity to this hormone is elevated. It is therefore crucial that we understand how angiotensin II works and how its actions in the body are mediated. For angiotensin II to act it must first bind to a receptor. Receptors are proteins and behave like locks that are opened by the hormone keys. Thus, cellular receptors for angiotensin II are engaged and activated by increases in angiotensin II in our blood. These receptors then produce signals which initiate a response (e.g. constriction of a blood vessel). Subsequently, the receptors are switched-off to prevent over-stimulation. The experiments proposed in this application continue our investigations into how angiotensin II receptors are regulated or switched-on and -off. A major way for receptors to be turned off is for them to be ear-marked by a modification known as phosphorylation. These modified receptors are then bound by proteins termed arrestins, which as indicated by their name play a role in preventing further receptor signalling. These arrestins also help remove activated receptors from the cell surface to the inside of the cell. How arrestins interact with receptors and regulate their function is poorly understood. This application proposes experiments to investigate the molecular mechanisms of arrestin action as it relates to the angiotensin II receptor. Results from these studies will further our understanding of angiotensin II receptors and their role in cardiovascular control.Read moreRead less