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
The Role Of A Novel Extracellular Matrix Protein, WARP, In Cartilage Development, Function And Pathology
Funder
National Health and Medical Research Council
Funding Amount
$482,500.00
Summary
The environment outside all cells is absolutely essential for normal growth and development. In order to undertand many disease and developmental processes it is critical that we acquire a detailed understanding of the various extracellular matrix components and how they interact to form a functional extracellular matrix. We recently discovered a new extracellular matrix protein which we have named WARP for von Willebrand factor A-domain-related protein. Our experiments demonstrate that WARP is ....The environment outside all cells is absolutely essential for normal growth and development. In order to undertand many disease and developmental processes it is critical that we acquire a detailed understanding of the various extracellular matrix components and how they interact to form a functional extracellular matrix. We recently discovered a new extracellular matrix protein which we have named WARP for von Willebrand factor A-domain-related protein. Our experiments demonstrate that WARP is an important constituent of the three-dimensional structure of the extracellular matrix of the articular surface of cartilage. We can show that WARP forms large-scale structures in tissue culture experiments and in extracts from mouse cartilage, and we have some new data which suggests that WARP interacts specifically with collagen II, a large and quantitatively major component of cartilage. We will explore the function of WARP in cartilage and include in vitro experiments that will reveal information about its distribution, tissue forms, and interactions with other extracellular matrix components (PART 1). To define the in vivo role of WARP we will generate a WARP gene knockout mouse (PART 2). These experiments will provide valuable information about the structure of the cartilage in the joint on the surface of bone and in particular the function of WARP in this structure. Since WARP is at the articular cartilage surface we asked whether WARP is lost in cartilage degeneration. In cartilage tissue grown in vitro under conditions that promote cartilage degradation, WARP is fragmented and released from the cartilage surface. We will explore this further in in vitro and in vivo models of cartilage breakdown (PART 3). Thus, in addition to promoting a new understanding of cartilage structure WARP has the exciting potential to become a specific biomarker for arthritis a major joint degenerative disease with high medical and financial cost to the community.Read moreRead less
Role And Mechanism Of Connective Tissue Growth Factor In Diabetic Cardiomyopathy
Funder
National Health and Medical Research Council
Funding Amount
$382,820.00
Summary
Diabetic cardiomyopathy is a condition where the heart muscle is directly damaged by diabetes. It is being recognised as a prominent cause of both acute and chronic heart failure in diabetes. It is common and occurs in up to 60% of diabetic patients . At present however, no treatments are available to directly treat the cardiomyopathy. This condition can also occur in people with diabetes who have high blood pressure and-or coronary artery disease and may combine with these problems to worsen pa ....Diabetic cardiomyopathy is a condition where the heart muscle is directly damaged by diabetes. It is being recognised as a prominent cause of both acute and chronic heart failure in diabetes. It is common and occurs in up to 60% of diabetic patients . At present however, no treatments are available to directly treat the cardiomyopathy. This condition can also occur in people with diabetes who have high blood pressure and-or coronary artery disease and may combine with these problems to worsen patient outcomes. We have generated data in experimental diabetes in rodents that strongly implicates a heart growth factor in causing diabetic cardiomyopathy. This protein, called connective tissue growth factor (CTGF), is increased in diabetic cardiomyopathy, and is elevated by high glucose and other factors in diabetes. We have published data showing that CTGF causes tissue scarring like that which occurs in cardiomyopathy, by affecting signals in cells called fibroblasts. It increases the laying down of extracellular matrix (ECM) and also inhibits the degradation of ECM by the proteins that break down matrix, known as the MMPand PAI systems. Such accumulation of ECM is thought to be a major factor leading to abnormal muscle function in cardiomyopathy. We now plan to block CTGF in this diabetic heart model to determine if we can prevent diabetic cardiomyopathy. We have generated two methods to inhibit CTGF in the animal model. Echocardiography (a heart ultrasound test), and molecular analysis of the heart tissue will determine if we can prevent the otherwise adverse functional and structural changes of diabetes in the heart. We will also study our baboon model of diabetes to determine if diabetic cardiomyopathy with increased heart CTGF is present in the primates. Cell culture studies from rat heart fibroblasts and myocytes will determine how CTGF has the effect on cells to cause cardiomyopathy and how we might further prevent this condition developing in diabetes.Read moreRead less
Cartilage Destruction In Arthritis: Mechanism Of Aggrecanase And Matrix Metalloproteinase Action In Vivo And In Vitro
Funder
National Health and Medical Research Council
Funding Amount
$703,180.00
Summary
Arthritis is a disease that causes pain, deformity and disability. The lack of adequate therapies for arthritis is partly a reflection of our limited understanding of the biochemical events involved in disease progression and cartilage destruction. Two distinct families of enzymes are present in cartilage. These are the MMP and the ADAMTS family. These enzyme families are important for cartilage turnover in normal growth and skeletal development. However unregulated enzyme activity resulting in ....Arthritis is a disease that causes pain, deformity and disability. The lack of adequate therapies for arthritis is partly a reflection of our limited understanding of the biochemical events involved in disease progression and cartilage destruction. Two distinct families of enzymes are present in cartilage. These are the MMP and the ADAMTS family. These enzyme families are important for cartilage turnover in normal growth and skeletal development. However unregulated enzyme activity resulting in accelerated cartilage breakdown leads to the pathology recognised as arthritis. While some activities of the MMP and ADAMTS families have been studied in the laboratory, there have been no in vivo studies to determine which family is responsible for cartilage destruction, and which is therefore most appropriate for targeting by drugs. This project will create genetically-modified mice, resistant to either the MMP or the ADAMTS enzymes. The mice will be used in experimental arthritis models to determine which enzymes play the major role in initiating disease, which enzymes are involved in disease progression and which enzymes may be important for repair. In parallel studies, the highly specialised matrix molecule, keratan sulphate, will be studied for its role in cartilage destruction. There is preliminary evidence to suggest that keratan sulphate may be involved in the regulation of ADAMTS activity. The possible direct and indirect modalities of keratan sulphate action will be investigated. The results of this arthritis project will (a) yield new information on the mechanism of disease action; (b) identify targets for the rational design of disease-modifying drugs; (c) elucidate biochemical processes involved in normal skeletal growth and cartilage repair; and (d) provide new in vivo models for testing the efficacy of arthritis therapies.Read moreRead less
Regulation Of Synthesis, Dimerisation And Secretion Of The Amyloidogenic Protease Inhibitor Cystatin C
Funder
National Health and Medical Research Council
Funding Amount
$423,565.00
Summary
The cells that compose our tissues are embedded in a complex mesh of extracellular proteins (for example collagen) that provide support, strenght and elasticity to the tissues. This extracellular matrix is not static; it is constantly remodelled when, for example, the cells of the immune system move through interstitial spaces to monitor the healthiness of the tissues. When infections or injuries occur, the inflammatory reactions that develop, and the processes involved in tissue repair, also in ....The cells that compose our tissues are embedded in a complex mesh of extracellular proteins (for example collagen) that provide support, strenght and elasticity to the tissues. This extracellular matrix is not static; it is constantly remodelled when, for example, the cells of the immune system move through interstitial spaces to monitor the healthiness of the tissues. When infections or injuries occur, the inflammatory reactions that develop, and the processes involved in tissue repair, also involve profound changes in the composition of the extracellular matrix. Such processes are also important for tumour growth; the cancer cells need to clear their way through interstitial space to escape to circulation and metastasize. During all these processes, the cells release to the extracellular space proteases that degrade collagen and the other components of the extracellular matrix. Obviously, these proteases must be tightly regulated to prevent them running out of control, so the cells also produce inhibitors of the proteases. The amount of proteases and inhibitors contained in the extracellular space must be maintained properly. If this equilibrium is disrupted, this can lead to pathology For instance, atherosclerosis is caused in part by excessive proteolysis of the blood vessel wall. In this project we want to study the mechanisms of one of the most abundant and important inhibitors of extracellular proteolysis: Cystatin C. We have discovered that certain cells of the immune system called dendritic cells posses interesting mechanisms to regulate how much Cystatin C they secrete. Furthermore, one of this mechanisms, which consists of pairing the protein to produce inactive dimers, may be the cause of some diseases characterised by accumulation of Cystatin C in the extracellular space. Our study may allow us to design therapies for the treatment of pathologies associated with defective or excessive production of Cystatin C.Read moreRead less
Harnessing The Extracellular Matrix To Fight Obesity-induced Cognitive Impairment
Funder
National Health and Medical Research Council
Funding Amount
$645,205.00
Summary
The health burden of obesity in Australia is great, but the detrimental impact of obesity on brain function is not yet understood. This research program takes an innovative approach to define how obesity changes non-neuronal brain components that regulate neuroplasticity and protect neurons from damage. Outcomes will define new mechanisms to prevent obesity-induced cognitive impairment and critical knowledge gain leading to novel therapeutic approaches and policy changes to improve health.
The Collagen-rich Matrix As A Driver Of Breast Cancer Progression And Resistance To Therapy
Funder
National Health and Medical Research Council
Funding Amount
$702,230.00
Summary
The extracellular matrix or 'matrix' surrounds all cells and is very important in controlling cell behaviour. In cancer, the matrix is dramatically altered, making cancer more aggressive. We recently developed a new way to study the matrix in breast cancer, and have analysed the matrix at different stages (Early/Mid/Late). We have uncovered exciting new matrix targets associated with more aggressive tumours. This project will validate their potential as therapeutic targets in breast cancer.
Defective Cell Migration As A Mechanism Of Dysregulated Asthmatic Airway Repair
Funder
National Health and Medical Research Council
Funding Amount
$616,712.00
Summary
Injury of the airway epithelium (cells lining the airways) is normally repaired by a process involving the deposition of specific proteins by the airway epithelial cells, promoting them to attach and migrate to cover the injury. These cells appear to be abnormal in asthmatics, in that they fail to repair. By studying specimens from healthy, allergic and asthmatic children we will determine the factors that influence the ability of these cells to repond to an injury in a normal manner specificall ....Injury of the airway epithelium (cells lining the airways) is normally repaired by a process involving the deposition of specific proteins by the airway epithelial cells, promoting them to attach and migrate to cover the injury. These cells appear to be abnormal in asthmatics, in that they fail to repair. By studying specimens from healthy, allergic and asthmatic children we will determine the factors that influence the ability of these cells to repond to an injury in a normal manner specifically through their ability to migrate.Read moreRead less