Dilinoleoyl Phosphatidic Acid As A Novel Mediator Of Insulin Resistance In Muscle
Funder
National Health and Medical Research Council
Funding Amount
$504,097.00
Summary
We have identified a novel fat molecule in muscle which may play an important role in causing insulin resistance during obesity, a major factor in the development of Type 2 diabetes. We will now examine whether depletion of this molecule, dilinoleoyl-phosphatidic acid, can improve insulin action in muscles and in obese mice, and investigate the mechanisms by which it may act. This work may indicate new strategies for the treatment of diabetes.
Bone Fragility: The Neglected Role Of Cortical Porosity
Funder
National Health and Medical Research Council
Funding Amount
$620,381.00
Summary
Cortical (outer shell) or compact bone constitutes 80% of the skeleton. It is not solid as implied by its name but made of inter-connected canals resembling a network of roads. We recently discovered that most of the bone loss with age occurs from these canals, not from t rabecular bone as currently believed. This suggests to know why and how bone breaks requires the study of the morphology of these canals and how they change with age. This is what we propose to do. It has never been done.
Is Periosteal Bone Formation Responsible For Sexual Dimorphism In Bone Fragility
Funder
National Health and Medical Research Council
Funding Amount
$316,320.00
Summary
Men and women sustain fractures as they age because their bones become fragile. Women sustain fractures more often than men. Bone thinning occurs in both sexes but it is usually believed that this thinning or loss of bone is greater in women than men. We have evidence to suggest that this may not be correct. In fact, it is likely that men and women lose a similar amount of bone, about half what they started with, but during ageing, men lay down more bone on the outside surface of the bone than w ....Men and women sustain fractures as they age because their bones become fragile. Women sustain fractures more often than men. Bone thinning occurs in both sexes but it is usually believed that this thinning or loss of bone is greater in women than men. We have evidence to suggest that this may not be correct. In fact, it is likely that men and women lose a similar amount of bone, about half what they started with, but during ageing, men lay down more bone on the outside surface of the bone than women compensating for the similar amount lost on the inside of the bone. We also have evidence to suggest than men and women who get spine fractures do so because the process of laying down bone may fail to occur normally. We will study these processes of bone loss inside the bone and bone gain outside the bone to try to better understand why bones become weak. We will measure the bone size and its density in healthy men and women and patients with fractures to determine how the increasing size of the bone produced by laying down bone on its outside helps to keep it strong and to preserve the bone that would otherwise be lost if it didn't occur or if a disease developed that might reduce the compensatoryRead moreRead less
Characterisation Of Novel AGE Binding Proteins: Implications For Diabetic Vascular Complications.
Funder
National Health and Medical Research Council
Funding Amount
$210,990.00
Summary
This project will explore a process known as advanced glycation and in particular how this may lead to organ injury in diabetes. Diabetes is characterised by sustained elevation of blood glucose levels which interact with proteins to generate products known as advanced glycation end-products (AGEs). These AGEs bind to other proteins some of which have been isolated and are considered receptors. Our own group has identified a new family of proteins known as ERM proteins which bind to AGEs. This i ....This project will explore a process known as advanced glycation and in particular how this may lead to organ injury in diabetes. Diabetes is characterised by sustained elevation of blood glucose levels which interact with proteins to generate products known as advanced glycation end-products (AGEs). These AGEs bind to other proteins some of which have been isolated and are considered receptors. Our own group has identified a new family of proteins known as ERM proteins which bind to AGEs. This is a highly novel finding which now needs to be examined in more detail. The ERM proteins which include ezrin, radixin and moiesin are found at many sites of diabetic complications including the kidney, retina and blood vessel wall. They have a number of functions including effects on cell adhesion and cell structure. This is important in diabetes where changes in cells including altered structure have been observed. This grant will characterise the interactions between AGEs and ERM proteins at the molecular and cellular level. It will define how AGEs influence cells via interactions with ERM proteins. These studies have the potential to lead to treatments that may modulate the AGE-ERM interactions, thereby retarding or preventing diabetic vascular complications. These complications are of important clinical significance since they are the major cause of morbidity and mortality in the diabetic population. Furthermore, diabetes is a major cause of premature atherosclerosis in our community, diabetic kidney disease is the leading cause of end-stage renal failure in the Western world and diabetic retinopathy (eye disease) is the main cause of blindness in the working age population.Read moreRead less
Endocrine And Autocrine Regulation Of Breast Cancer Cell Growth By IGF Binding Protein-3 (IGFBP-3).
Funder
National Health and Medical Research Council
Funding Amount
$497,250.00
Summary
The insulin-like growth factor (IGF) system of growth factors and their regulatory proteins is essential for normal growth, but is also involved in a number of overgrowth disorders. Some clinical studies have shown that a high level of IGF-I in the blood increases the risk of breast cancer in some women, but if the protein which carries it in the circulation, IGFBP-3, is also high, the risk is reduced. It has therefore been suggested that IGFBP-3 may be useful in the treatment of breast cancer. ....The insulin-like growth factor (IGF) system of growth factors and their regulatory proteins is essential for normal growth, but is also involved in a number of overgrowth disorders. Some clinical studies have shown that a high level of IGF-I in the blood increases the risk of breast cancer in some women, but if the protein which carries it in the circulation, IGFBP-3, is also high, the risk is reduced. It has therefore been suggested that IGFBP-3 may be useful in the treatment of breast cancer. This is supported by laboratory studies showing that IGFBP-3 can inhibit cell division and stimulate cell death in many cell types, including breast cells. However, some cells are resistant to IGFBP-3 s inhibitory effects, and in some cases IGFBP-3 may stimulate cells to grow and divide. In fact, the amount of IGFBP-3 present in breast tumours is highest in the fastest growing, most malignant tumours, suggesting that IGFBP-3 may be stimulating their growth. Our laboratory data indicates that breast cancer cells which produce a high level of IGFBP-3 grow faster as tumours than cells which produce little or no IGFBP-3. We believe that this is because IGFBP-3 interacts with another hormone system which is involved in rapid tissue growth, the EGF system, and increases its ability to stimulate breast cells to divide. These observations raise a number of important questions: how does IGFBP-3 interact with the EGF system to stimulate tumour growth; does IGFBP-3 from the blood promote the growth of EGF-sensitive tumours; and can the interaction between IGFBP-3 and the EGF system be abolished, or switched from growth stimulatory to growth inhibitory, thus inhibiting tumour growth. Answering these questions will provide important new information regarding IGFBP-3 s stimulatory and inhibitory actions, and the role of endocrine IGFBP-3 in tumour growth, and have the potential to lead to the development of novel therapies involving IGFBP-3 for the treatment of overgrowth disorders.Read moreRead less
The Role Of Ghrelin And Growth Hormone Releasing Hormone In The Autocrine Regulation Of Prostate Cancer Cell Growth
Funder
National Health and Medical Research Council
Funding Amount
$240,990.00
Summary
Insulin-like growth factor-I (IGF-I) is an important growth factor with a major role in the growth and development of many normal and tumour cells. Its production is controlled by growth hormone (GH), released from the pituitary gland at the base of the brain. GH releasing hormone (GHRH), a hormone released from higher centres in the brain, regulates the production of GH itself and now it is recognised that a second pathway, the ghrelin-GH secretagogue receptor (GHS-R) axis is also important in ....Insulin-like growth factor-I (IGF-I) is an important growth factor with a major role in the growth and development of many normal and tumour cells. Its production is controlled by growth hormone (GH), released from the pituitary gland at the base of the brain. GH releasing hormone (GHRH), a hormone released from higher centres in the brain, regulates the production of GH itself and now it is recognised that a second pathway, the ghrelin-GH secretagogue receptor (GHS-R) axis is also important in regulating GH release. There is growing evidence that the GHRH-GH-IGF axis has a significant role in prostate cancer, but little is known about how this happens. We also have evidence that the ghrelin-GHS-R axis is involved in prostate cancer, as prostate cancer cell lines produce both ghrelin and the receptor through which it acts. Our preliminary studies show that ghrelin enhances cell growth in these cells. GHRH blocking agents (antagonists) are potential treatments for prostate cancer, as they slow the growth of prostate tumours. How they act is unclear, but they might interfere with a locally active GHRH pathway in the prostate. This study aims to explore the role of ghrelin and GHRH in prostate cancer. Since there is an increase in the use of GHRH, GH and-or IGF-I and potentially ghrelin for the treatment of a variety of medical conditions, including some in the aging male, the need for a fuller understanding of the role of this axis in prostate cancer is increasingly important. Such information will lead to a deeper understanding of the actions of ghrelin and GHRH and provide potential opportunities for design of new therapies for prostate and other GH-IGF-responsive tumours.Read moreRead less
Insulin-like Growth Factor Binding Protein-3 (IGFBP-3) Sensitivity And Signalling In Breast Cancer
Funder
National Health and Medical Research Council
Funding Amount
$414,343.00
Summary
The growth of all tissues in the body depends on many growth factors, hormones and other proteins which work together to control cell division. Some of these factors stimulate the division of the cells which make up the body tissues, and some inhibit it, so that a balance of these stimulators and inhibitors ensures that tissues do not grow too fast, or too large. The development of breast cancer and the growth of breast tumours is thought to be due to uncontrolled or faulty actions of the protei ....The growth of all tissues in the body depends on many growth factors, hormones and other proteins which work together to control cell division. Some of these factors stimulate the division of the cells which make up the body tissues, and some inhibit it, so that a balance of these stimulators and inhibitors ensures that tissues do not grow too fast, or too large. The development of breast cancer and the growth of breast tumours is thought to be due to uncontrolled or faulty actions of the proteins and hormones which regulate the way breast cells multiply. One protein which normally regulates the division of breast cells is IGFBP-3. We have found that in some breast cancer cells, IGFBP-3 is no longer able to inhibit cell division, and this may lead to tumour growth and invasion of other tissues. We are interested in finding out how IGFBP-3 normally controls breast cell proliferation, and why some breast cancers are resistant to IGFBP-3. To do this, we will use normal breast cells in culture to examine how IGFBP-3 interacts with other cellular factors to prevent cell division. We will then look at whether the breast cancer cells have changed so that they are no longer able to recognise IGFBP-3 as an inhibitory protein. This may be because of changes in the way IGFBP-3 binds to the breast cancer cell, or because of changes in the way it interacts with other proteins in the cell. Because IGFBP-3 is made by normal and breast cancer cells, we will also study whether the IGFBP-3 being made by breast cancer cells is normal, or if it changed in some way that makes it inactive. By understanding why some breast cancers are not inhibited by IGFBP-3, we will be able to design new and better methods of preventing, detecting and treating the growth of all breast tumours.Read moreRead less
Epidermal Growth Control In Psoriasis And Normal Skin
Funder
National Health and Medical Research Council
Funding Amount
$451,980.00
Summary
Our skin protects us from damage, dehydration, infection and harmful UV radiation. At the same time, we expect it to remain healthy, smooth and looking good. How the skin, and more particularly its upper layer, the epidermis, adapts to all these requirements is a complex problem yet to be fully understood. This question forms the basis of our project proposal. The epidermis is a continuously self-renewing tissue, in which cells have an average life of 30 days before they are invisibly shed to th ....Our skin protects us from damage, dehydration, infection and harmful UV radiation. At the same time, we expect it to remain healthy, smooth and looking good. How the skin, and more particularly its upper layer, the epidermis, adapts to all these requirements is a complex problem yet to be fully understood. This question forms the basis of our project proposal. The epidermis is a continuously self-renewing tissue, in which cells have an average life of 30 days before they are invisibly shed to the outside. In normal states and when responding to injury or disease, this cell turnover speed can be finely tuned, for example accelerated in the case of a healing wound. In contrast, if damaged by the sun, epidermal cells undergo a form of cell suicide (apoptosis) to prevent tumours forming from cells with damaged genes. This changing turnover speed is controlled by a series of growth factors, or cytokines. Insulin-like growth factor-I (IGF-I) is a unique cytokine that can control both cell turnover rate, and cell death. We aim to uncover the complex biochemical interactions that allow the epidermal IGF-I system to achieve this seemingly contradictory task. This study is important because when the epidermis loses the ability to finely tune its turnover speed, ulcers, sun damage, the common skin disorder psoriasis, or worse still, skin tumours, arise. This project explores ways of manipulating the IGF-I system to prevent this, and builds on some technology developed by the research group that has already proven effective in the control of psoriasis. The project also promises to discover undiscovered growth regulators that could be used in new gene therapies for skin overgrowth diseases.Read moreRead less
Role Of Impaired Insulin Signalling In Fatty Acid-induced Muscle Insulin Resistance In Vivo
Funder
National Health and Medical Research Council
Funding Amount
$481,500.00
Summary
Type 2 diabetes represents an escalating global health problem. In Australia 7.5% of the population has diabetes and another 16% insulin resistance (impaired action of insulin in tissues). As well as diabetes, insulin resistance is closely associated with obesity, dyslipidaemia, hypertension and cardiovascular diseases (Syndrome X). While genetic factors play a role, a high caloric intake (particularly with a high fat content) and a sedentary lifestyle are extremely important environmental contr ....Type 2 diabetes represents an escalating global health problem. In Australia 7.5% of the population has diabetes and another 16% insulin resistance (impaired action of insulin in tissues). As well as diabetes, insulin resistance is closely associated with obesity, dyslipidaemia, hypertension and cardiovascular diseases (Syndrome X). While genetic factors play a role, a high caloric intake (particularly with a high fat content) and a sedentary lifestyle are extremely important environmental contributors to Syndrome X and diabetes. From evidence that we and others have obtained over the last few years it is now evident that an important mediator of insulin resistance is the quantity of fat molecules which accumulate in muscle and liver. This project examines mechanisms whereby this fat accumulation can disrupt the signalling mechanism normally causing increased glucose metabolism in response to insulin. While basic experiments in cell systems have identified some candidates, a need exists to demonstrate whether they actually cause the insulin resistance in the whole animal or human, or are merely associated with it. We will combine metabolic-physiological studies with a novel technique we have recently established in our laboratory for introducing DNA into skeletal muscle of laboratory animal models. We now aim to exploit this approach to obtain more definitive data about the importance of insulin signalling changes to insulin resistance. Two major steps in insulin signalling will be investigated, involving the insulin receptor substrate proteins and the kinase Akt-PKB, both strongly implicated in lipid-induced insulin resistance. This knowledge will be invaluable in improving strategies to lessen or prevent lipid-associated insulin resistance, a major contributor to the metabolic derangement in Type 2 diabetes and Syndrome X.Read moreRead less
Functional Role Of A Novel Coregulator In Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$563,146.00
Summary
Australia is facing a massive epidemic of diabetes and obesity (diabesity). These disorders afflict all age groups, including teenagers, and are a major burden to the health and wealth of Australia. The nuclear receptors and their coregulators are excellent targets for developing new therapeutics to combat these disorders. This grant will evaluate the functional role of SLIRP, a novel nuclear receptor coregulator, in metabolism and could provide new avenues for drug target development.