Development Of A Protein Tyrosine Kinase Inhibitor For Modification Of GAG Chains And Prevention Of Atherosclerosis
Funder
National Health and Medical Research Council
Funding Amount
$389,778.00
Summary
The major health issue in Australia is vascular and cardiovascular disease resulting from obesity and diabetes. Whilst prevention strategies based on lifestyle changes are preferable, treating cardiovascular risk factors with the latest drugs has been shown to produce significant benefits. There is however a large group of patients who still acquire cardiovascular disease in spite of drug therapy. New therapies are required and these will most likely target blood vessels directly. We have identi ....The major health issue in Australia is vascular and cardiovascular disease resulting from obesity and diabetes. Whilst prevention strategies based on lifestyle changes are preferable, treating cardiovascular risk factors with the latest drugs has been shown to produce significant benefits. There is however a large group of patients who still acquire cardiovascular disease in spite of drug therapy. New therapies are required and these will most likely target blood vessels directly. We have identified a biochemical mechanism that represents a prime target for vascular wall directed therapy and we aim to exploit the therapeutic potential of this pathway by developing a drug to prevent atherosclerosis. A group of large molecules which have recently received increasing attention are the proteoglycans, combined protein-sugar molecules which are heavily coated with negatively charged groups. The binding and retention of lipids in the wall of the blood vessel is the main cause of atherosclerosis. Specifically, the length of the sugar (GAG) chains on the proteoglycans determines the binding of the lipids. We have discovered a new class of inhibitors which directly target proteoglycan synthesis in the vessel wall and greatly reduce the interaction between proteoglycans and lipids. We wish to demonstrate the efficacy of our compound in an animal model with the aim to produce a marked reduction in the rate and extent of development of atherosclerosis. This would lay the foundation for the compound to be taken into human safety trials and subsequently develop an agent for the prevention of atherosclerosis and a thus a reduction in cardiovascular disease.Read moreRead less
Chronic pain affects 1 in 5 Australians and neuropathic pain is among the most severe forms of chronic pain. Several peptides derived from cone snail venoms have attracted recent attention as potential therapeutic agents for the treatment of neuropathic pain. One of these, conotoxin MVIIA, has recently been approved in the US and Europe and others, including CVID and ACVI, are in various stages of clinical investigation. These small disulfide rich peptides share the attractive features of peptid ....Chronic pain affects 1 in 5 Australians and neuropathic pain is among the most severe forms of chronic pain. Several peptides derived from cone snail venoms have attracted recent attention as potential therapeutic agents for the treatment of neuropathic pain. One of these, conotoxin MVIIA, has recently been approved in the US and Europe and others, including CVID and ACVI, are in various stages of clinical investigation. These small disulfide rich peptides share the attractive features of peptides in general of having exquisite selectivity for particular receptors, but also share the general disadvantages of peptides of short biological half-lives and poor bioavailablility. Stabilisation of these conotoxins has the potential to substantially increase their therapeutic potential. In preliminary studies we have shown that by introducing a circular petide backbone into a conotoxin using a linker sequence we can increase its stability and resistance to enzymatic degradation. We therefore propose that it will be possible to cyclise a wide range of conotoxin molecules and thereby improve their drug like properties. In this project we will use our cyclisation approach to develop new potential treatments for pain from two classes of conotoxins. One of the lead molecules shows oral bioavailability in an animal pain model and potentially represents a major breakthrough in the field of peptide drug delivery.Read moreRead less
Molecular Toxinology Of Australian Box Jellyfish Venoms
Funder
National Health and Medical Research Council
Funding Amount
$283,110.00
Summary
Box jellyfish are an ongoing cause of illness and death for coastal communities and tourist regions in northern Australia. As well as creating a significant medical problem, the resulting closure of beaches during boxjellyfish 'season' results in an enormous loss of tourism income and threatens Australia's reputation as a safe destination. The jellyfish venoms contain toxins with potentially lethal effects on humans. For the first time, using pure venoms derived from the specialised stinging cel ....Box jellyfish are an ongoing cause of illness and death for coastal communities and tourist regions in northern Australia. As well as creating a significant medical problem, the resulting closure of beaches during boxjellyfish 'season' results in an enormous loss of tourism income and threatens Australia's reputation as a safe destination. The jellyfish venoms contain toxins with potentially lethal effects on humans. For the first time, using pure venoms derived from the specialised stinging cells (i.e. nematocytsts), we will isolate and characterize the major toxins from four species of box jellyfish. Their mechanism of action will be determined and the effect of various treatments such as antivenom will be investigated. This will also lead to the discovery of toxins with potentially novel targets and modes of action and increase our understanding of proposed treatments and prevention of stings.Read moreRead less
Regulation Of Human Arylamine N-acetyltransferase Transcription, Translation And Protein Stability
Funder
National Health and Medical Research Council
Funding Amount
$470,958.00
Summary
Individuals respond very differently to many drugs and other chemicals in the diet and workplace. This variation can be a significant complication in treating patients and in attempting to determine risk with exposure to toxins. Genetic differences between individuals are a common reason for this variation. However, many enzymes and other proteins in humans are controlled by environmental factors that can either increase their activity or inhibit it. In this study, we will investigate how the ac ....Individuals respond very differently to many drugs and other chemicals in the diet and workplace. This variation can be a significant complication in treating patients and in attempting to determine risk with exposure to toxins. Genetic differences between individuals are a common reason for this variation. However, many enzymes and other proteins in humans are controlled by environmental factors that can either increase their activity or inhibit it. In this study, we will investigate how the activity of an important family of enzymes (the acetyltransferases) varies between individuals as a result of environmental factors. We will look at the genes for each of the enzymes and learn about this control mechanism. We will also look careful at the structure of the proteins and determine how this may change when challenged with external stimuli. The expected outcome will be a better understanding of these important enzymes that are involved in the metabolism of many drugs, and also provide a means of determining how different individuals may respond to foreign chemicals and drugs that use these enzymes in the body for metabolism.Read moreRead less
UDP Glucuronosyltransferases As Regulators Of Signaling Pathways Modulated By Chemical Ligands.
Funder
National Health and Medical Research Council
Funding Amount
$500,460.00
Summary
Cells respond to their surroundings by transferring information received at the cell surface to the nucleus leading to changes in gene expression. There are many signaling pathways which transfer this informatrion to the nucleus. Some of these pathways are controlled by small molecules, usually fat-soluble chemicals. As a family of enzymes, the UDP glucuronosyltransferases (UGT) have evolved to eliminate fat-soluble chemicals, we propose that UGTs play a pivotal role in regulating the concentrat ....Cells respond to their surroundings by transferring information received at the cell surface to the nucleus leading to changes in gene expression. There are many signaling pathways which transfer this informatrion to the nucleus. Some of these pathways are controlled by small molecules, usually fat-soluble chemicals. As a family of enzymes, the UDP glucuronosyltransferases (UGT) have evolved to eliminate fat-soluble chemicals, we propose that UGTs play a pivotal role in regulating the concentrations of fat-soluble chemicals involved in signaling, and thus are important in controlling gene expression. We intend to provide evidence for this novel role of UGTs in this project. This information will be used to alter the response of the cell to its environment. For example, to help protect the cell against environmental toxins, or to make a cancer cell more susceptible to a chemotherapeutic agent.Read moreRead less
Probing UDP-glucuronosyltransferase Protein-protein Interactions: The Power Of Two.
Funder
National Health and Medical Research Council
Funding Amount
$482,710.00
Summary
Drugs and other chemicals (eg. dietary constituents, environmental pollutants, and chemicals that occur naturally in the body - such as steroid hormones) are broken down by specialised proteins called enzymes. This process is referred to as biotransformation, or 'metabolism'. Drug and chemical metabolism serves as a detoxification mechanism (since the products of metabolism generally lack biological activity) and as a means of eliminating these substances from the body. UDP-Glucuronosyltransfera ....Drugs and other chemicals (eg. dietary constituents, environmental pollutants, and chemicals that occur naturally in the body - such as steroid hormones) are broken down by specialised proteins called enzymes. This process is referred to as biotransformation, or 'metabolism'. Drug and chemical metabolism serves as a detoxification mechanism (since the products of metabolism generally lack biological activity) and as a means of eliminating these substances from the body. UDP-Glucuronosyltransferase (UGT) is one of the most important enzymes involved in drug and chemical metabolism. Consistent with its ability to metabolise such a large number of compounds, UGT is known to exist as a 'superfamily' of structurally related proteins. Despite the importance of UGT, little is known about the structural characteristics of these enzymes that are responsible for recognising and binding different classes of chemicals. Accumulating evidence from this and other laboratories indicates that the individual UGT proteins may combine with themselves (to form a homodimer) and with other UGT proteins (to form heterodimers). This project largely seeks to define the scope of UGT homo- and hetero- dimerisation, identify the structural elements of the proteins responsible for association and characterise the functional significance of dimerisation. The project will further explore associations between UGTs and other proteins, namely albumin. Characterisation of UGT dimerisation and associations with other proteins is fundamental to our understanding of how this enzyme functions and selects particular chemicals for metabolism. The work also has important implications for the devlopment and interpretation of in vitro (or 'test-tube') approaches for predicting how drugs are metabolised in humans. Such tests are widely employed in research and pharmaceutical company laboratories to predict how the body 'handles' new drugs prior to their administration to humans.Read moreRead less
Biological Membrane Transporters: Delivery Of An Oligonucleotide Inhibitor Of Vascular Endothelial Growth Factor (VEGF)
Funder
National Health and Medical Research Council
Funding Amount
$99,750.00
Summary
Choroidal neovascularisation, which is the most severe form of Age Related Macular Degeneration, is the major cause of blindness in the developed world. Gene therapy could be a cure for this disease if the problems associated with the delivery of DNA could be addressed. Our project involves a highly novel strategy for gene delivery involving ion pair formation of lipophilic dendrimers (tree-like compounds with positive charges on the surface). We will develop new DNA-dendrimer complexes and test ....Choroidal neovascularisation, which is the most severe form of Age Related Macular Degeneration, is the major cause of blindness in the developed world. Gene therapy could be a cure for this disease if the problems associated with the delivery of DNA could be addressed. Our project involves a highly novel strategy for gene delivery involving ion pair formation of lipophilic dendrimers (tree-like compounds with positive charges on the surface). We will develop new DNA-dendrimer complexes and test them in a well established animal model for neovascularisation. Successful completion of this project might offer a potential therapy for choroidal neovascularisation, with a good chance of entering into human clinical trials.Read moreRead less
Molecular Determinants Of UDP Glucuronosyltransferase 1A3 And 1A4 Expression
Funder
National Health and Medical Research Council
Funding Amount
$516,078.00
Summary
Enzymes in the liver and gastrointestinal tract have a crucial role in protecting against the toxic effects of fat-soluble chemicals. Two of these enzymes called UGT1A3 and UGT1A4 have a special role in protecting against drugs and toxins that contain nitrogen groups. The levels of these two enzymes in the liver and gut vary extensively between individuals. In this project we will determine how the levels of these enzymes are controlled and what is the cause of this variability between individua ....Enzymes in the liver and gastrointestinal tract have a crucial role in protecting against the toxic effects of fat-soluble chemicals. Two of these enzymes called UGT1A3 and UGT1A4 have a special role in protecting against drugs and toxins that contain nitrogen groups. The levels of these two enzymes in the liver and gut vary extensively between individuals. In this project we will determine how the levels of these enzymes are controlled and what is the cause of this variability between individuals. This will help us predict those individuals who are more at risk from the adverse effects of nitrogen-containing drugs and from the toxic effects of chemicals in the diet or the environment. This project will also help us develop methods to increase the levels of these protective enzymes and help reduce the effects of exposure to toxic chemicals.Read moreRead less
Expression And Regulation Of Human Genes Central To Drug Disposition In The Brain
Funder
National Health and Medical Research Council
Funding Amount
$339,375.00
Summary
The study of the regulation of human genes is inherently difficult. It is difficult or impossible to gain access to many body tissues in either healthy or sick individuals to examine coordinated gene function (or dysfunction). This is particularly true for the brain, where live human tissue is unavailable. For this reason, it is often the case that we have a much better understanding of gene function in species such as rats and mice, the most common animal environments for biomedical research. H ....The study of the regulation of human genes is inherently difficult. It is difficult or impossible to gain access to many body tissues in either healthy or sick individuals to examine coordinated gene function (or dysfunction). This is particularly true for the brain, where live human tissue is unavailable. For this reason, it is often the case that we have a much better understanding of gene function in species such as rats and mice, the most common animal environments for biomedical research. However, findings in animals often fail to meaningfully mirror what occurs in man. To progress our understanding of human genes in brain we need to develop models that more faithfully reproduce the human situation in an environment that is amenable to both manipulation and close examination, such as the novel 'humanized' mouse models described in this application. This application deals with the genes that control enzymes belonging to the human cytochrome P450 3A (CYP3A) subfamily and the drug transporter MDR1. These genes are present in several tissues including liver, gut, lung and brain. They form the main disposal pathway for foreign chemicals such as drugs, environmental pollutants and some cancer causing chemicals. In addition they are involved in the breakdown of several important internally produced substances, such as steroid hormones. We postulate that altered formation of CYP3A enzymes and MDR1 in brain can have a dramatic impact on the action of many important drugs and may affect the way the brain responds in a behavioral sense to hormones, such as sex steroids. In addition, this work will provide a new and useful information relevant to the design and development of the plethora of drugs that act on the central nervous system.Read moreRead less