The Role Of Intersectin-1 In Endocytic Anomalies: Implications For Down Syndrome And Alzheimer's Disease
Funder
National Health and Medical Research Council
Funding Amount
$510,500.00
Summary
Individuals with Down syndrome have three copies of human chromosome 21, rather than the normal two. We have discovered a gene called Intersectin-1, located on human chromosome 21, that is expressed at higher levels than normal in individuals with Down syndrome. Intersectin-1 has a role in endocytosis, a process whereby cells take up molecules from the outside. Endocytosis occurs in all cells but is highly specialised in the brain where chemical transmitters are released and then rapidly recover ....Individuals with Down syndrome have three copies of human chromosome 21, rather than the normal two. We have discovered a gene called Intersectin-1, located on human chromosome 21, that is expressed at higher levels than normal in individuals with Down syndrome. Intersectin-1 has a role in endocytosis, a process whereby cells take up molecules from the outside. Endocytosis occurs in all cells but is highly specialised in the brain where chemical transmitters are released and then rapidly recovered by endocytosis in a process enabling neurones to pass signals to one another. A disturbance in endocytosis has been reported as the earliest hallmark of Alzheimer's disease in both non-Down syndrome and Down syndrome individuals. This disturbance is characterised by the presence of enlarged endosomes (small packages in neuronal cells containing chemical neurotransmitters formed during endocytosis). These enlarged endosomes are present long before the characteristic plaques of Alzheimer's disease appear. Since all individuals with Down syndrome develop Alzheimer's-like neuropathology, there must be a common disease mechanism that can be traced to the extra gene dosage from chromosome 21. We propose that a malfunctioning of Intersectin-1 is this common mechanism and we aim to test our hypothesis by the generation and analysis of mouse models of disrupted endocytosis.Read moreRead less
Deciphering The Molecular Basis Of SM Regulation Of Exocytosis
Funder
National Health and Medical Research Council
Funding Amount
$515,564.00
Summary
Diabetes, obesity, heart disease and physical inactivity are major and escalating health problems within western societies. These problems are all linked to, or aggravate, the condition known as insulin resistance. Insulin resistance occurs when normal levels of insulin are insufficient to remove glucose from the blood. In the normal situation, insulin regulates glucose uptake into muscle and fat cells by stimulating the movement of a glucose transport protein from inside the cell to the cell su ....Diabetes, obesity, heart disease and physical inactivity are major and escalating health problems within western societies. These problems are all linked to, or aggravate, the condition known as insulin resistance. Insulin resistance occurs when normal levels of insulin are insufficient to remove glucose from the blood. In the normal situation, insulin regulates glucose uptake into muscle and fat cells by stimulating the movement of a glucose transport protein from inside the cell to the cell surface. The trafficking of this protein is somehow disrupted in insulin resistance. The purpose of this research is to follow up our exciting preliminary results on this system to shed light on the molecular processes that regulate the trafficking of the glucose transporter. Information resulting from our studies will lead to a better understanding of insulin-stimulated glucose transport and may also unravel the details of a related cellular secretion system that regulates neurotransmission. Our hope is that by understanding at the molecular level how cells regulate secretion, we can in the future develop therapeutics to counteract many of today s major health problems.Read moreRead less
Cellular Mechanisms And Physiological Roles Of GLUT12 Mediated Glucose Transport In Glucose Homeostasis
Funder
National Health and Medical Research Council
Funding Amount
$499,000.00
Summary
Diabetes affects almost one million Australians, although only 50% are aware they have the disease. Type 2 diabetes accounts for about 90% of diabetes and usually occurs after the age of 40. As a leading cause of death, adult blindness, lower limb amputation, kidney failure, stroke and heart attack, diabetes has huge economic and social consequences and has been designated an Australian National Health priority. A clinical feature of Type 2 diabetes is high blood glucose levels. This occurs beca ....Diabetes affects almost one million Australians, although only 50% are aware they have the disease. Type 2 diabetes accounts for about 90% of diabetes and usually occurs after the age of 40. As a leading cause of death, adult blindness, lower limb amputation, kidney failure, stroke and heart attack, diabetes has huge economic and social consequences and has been designated an Australian National Health priority. A clinical feature of Type 2 diabetes is high blood glucose levels. This occurs because insulin does not effectively stimulate the transfer of glucose from the blood into muscle and fat. The reasons for this are not fully understood. Insulin normally works to move glucose transporter (GLUT) proteins to the surface of muscle and fat cells. One GLUT that has been studied extensively in muscle and fat is GLUT4. GLUT4 moves to the cell surface in response to insulin and this response is one of the defects that is known to occur in Type 2 diabetes. Glucose then accumulates in the blood, leading to many of the complications of diabetes. We have discovered a novel glucose transporter, GLUT12, that is also present in muscle and fat. We have shown that GLUT12, like GLUT4, responds to insulin. GLUT12 could therefore be a critical backup for GLUT4. We have also found that GLUT12 responds to glucose itself, suggesting a unique role in controlling blood glucose levels. We will explore how GLUT12 acts in muscle and fat cells to find whether GLUT12 can act as a backup for GLUT4. We will also study GLUT12 in tissue from normal animals and in animals with features of Type 2 diabetes. To determine the role of GLUT12 in maintaining normal blood glucose levels, we will produce mice with an inactive GLUT12 gene. Our research could identify novel ways of increasing GLUT12 activity. The eventual goal will be to find a pharmaceutical compound that can improve glucose transport into muscle, reduce high blood glucose levels and thus the complications of Type 2 diabetes.Read moreRead less
MECHANISMS OF MOTILITY AND METASTASIS In BREAST CANCER
Funder
National Health and Medical Research Council
Funding Amount
$209,505.00
Summary
The broad aim of this proposal is to elucidate novel molecular mechanisms of breast cancer cell motility that are relevant to metastasis or the spread of cancer. The function of two genes will be studied. We propose that (1) reduced on-random motile (ROM) regulates the speed of cancer cell movement, and (2) Neural Wiskott-Aldrich syndrome protein (N-WASP) regulates the directional component of cell movement. We will relate the function of ROM and N-WASP to rapid, linear walking along collagen fi ....The broad aim of this proposal is to elucidate novel molecular mechanisms of breast cancer cell motility that are relevant to metastasis or the spread of cancer. The function of two genes will be studied. We propose that (1) reduced on-random motile (ROM) regulates the speed of cancer cell movement, and (2) Neural Wiskott-Aldrich syndrome protein (N-WASP) regulates the directional component of cell movement. We will relate the function of ROM and N-WASP to rapid, linear walking along collagen fibres in live tumours and to breast cancer metastasis to the lung. ROM will be inhibited in breast cancer cells and we expect increases in both the speed of cell movement and metastasis. Therefore, ROM functions as a suppressor of metastasis. Inhibition of N-WASP, however, is expected to compromise both the directionality of cell movement and metastasis. N-WASP is therefore, a promoter of metastasis. At the completion of this work, the regulatory mechanisms of motility and metastasis by ROM and N-WASP will be defined. This will facilitate the development of biologically targeted agents for ROM and N-WASP that can be used to control metastasis. In addition, these agents that target the motility pathway are appropriate for use in combined therapy with agents that target a different pathway such as survival or growth. This will significantly improve disease control rates or the proportion of patients with partial or complete disease regression. This proposal addresses the National Health Priority, cancer, and related National Research Priority, ageing well and ageing productively, where in the longer term, we will be able to create new and much needed therapy for metastasis.Read moreRead less