Hormones are essential chemical messengers that regulate the normal functions of the body. Reproduction in particular is widely influenced by hormones. The development of the very early embryo and its implantation into the uterus is not well understood. A new class of hormone has been implicated in this process. This hormone, known as platelet-activating factor (or PAF) is special among hormones since it belongs to a class of chemicals known as phospholipids. This is quite uncommon. This hormone ....Hormones are essential chemical messengers that regulate the normal functions of the body. Reproduction in particular is widely influenced by hormones. The development of the very early embryo and its implantation into the uterus is not well understood. A new class of hormone has been implicated in this process. This hormone, known as platelet-activating factor (or PAF) is special among hormones since it belongs to a class of chemicals known as phospholipids. This is quite uncommon. This hormone can act in an apparently contradictory fashion. Its production by the embryo allows it to act back on the embryo to stimulate embryo growth and survival. The embryo (of some species) then releases other hormones which prevents the PAF from acting on the uterus. If this repression of the uterine response to PAF does not occur then PAF acts on the uterus to stop further progression of the pregnancy (luteolysis). Hormones act on cells via special cell proteins known as receptors. It seems that the receptor for PAF in the embryo and the uterus are different and may therefore result in triggering different cellular responses by these 2 tissues. We have available to us mice with mutations that stop the functioning of these two likely classes of receptors. The progress of pregnancy and the development of embryos in mice with these mutations will be studied as a means of defining how PAF acts in pregnancy. The embryo will be studied in detail to determine the nature of the changes induced within the embryo by PAF acting via its receptor. One of these receptors is an entirely new class of molecules not previously understood to be able to act as a cell signalling devise. This study will describe if and how this potential new receptor acts in the embryo, allowing future detailed investigation of its role in normal cell function. It will show how this single hormone can regulate both the uterus and embryo to have contradictory roles in the establishment of pregnancy.Read moreRead less
Investigating The Link Between Oxidative Stress And Biomechanical Integrin Activation In Diabetes
Funder
National Health and Medical Research Council
Funding Amount
$653,742.00
Summary
Diabetes represents a serious healthcare problem globally. A large proportion of deaths associated with diabetes can be attributed to the development of blood clots in the circulation of the heart and brain (heart attack/stroke). The blood clotting mechanism is ‘hyperactive’ in diabetes, although the reason for this is not well defined. In this proposal we will investigate a new mechanism promoting blood clots, and will investigate innovative approaches to reduce this clotting mechanism.
Regulation Of Receptors That Control Platelet Function Under Shear Stress
Funder
National Health and Medical Research Council
Funding Amount
$507,273.00
Summary
Specialized human blood cells that control blood loss and clotting (platelets) are currently difficult to test in the clinical laboratory, meaning patients are at risk of excessive bleeding or serious clot formation during disease or treatment. The aim of this proposal is to use our new reagents and assays to develop more reliable methods for evaluating relative bleeding or clotting risk in individuals.
Identification Of A Novel Adhesion Mechanism Regulating Platelet-endothelial Interactions.
Funder
National Health and Medical Research Council
Funding Amount
$501,691.00
Summary
Platelets are important blood cells, stopping bleeding in the event of blood vessel injury. However, platelets can also interact with the blood vessel lining (endothelium) to regulate and in some cases promote inflammation. We have identified a new structure platelets use to stick to endothelium, which under disease states (enhanced oxidative stress), can promote inflammation. We will investigate how tractopods form, and examine their role in the setting of elevated oxidative stress and inflamma ....Platelets are important blood cells, stopping bleeding in the event of blood vessel injury. However, platelets can also interact with the blood vessel lining (endothelium) to regulate and in some cases promote inflammation. We have identified a new structure platelets use to stick to endothelium, which under disease states (enhanced oxidative stress), can promote inflammation. We will investigate how tractopods form, and examine their role in the setting of elevated oxidative stress and inflammatory disease.Read moreRead less
Ligand Interactions Of Platelet Glycoprotein Ib-IX-V In Thrombosis
Funder
National Health and Medical Research Council
Funding Amount
$363,098.00
Summary
The transition of circulating blood platelets from a fluid-phase, non-adherent state to an adherent, activated and aggregated state (thrombus formation) is critical in the normal haemostatic response to blood vessel injury and in thrombotic diseases such as heart attack and stroke. One unique platelet receptor, the glycoprotein Ib-IX-V complex, is of particular interest, because it initiates platelet aggregate or thrombus formation at high fluid shear stress in flowing blood, including the patho ....The transition of circulating blood platelets from a fluid-phase, non-adherent state to an adherent, activated and aggregated state (thrombus formation) is critical in the normal haemostatic response to blood vessel injury and in thrombotic diseases such as heart attack and stroke. One unique platelet receptor, the glycoprotein Ib-IX-V complex, is of particular interest, because it initiates platelet aggregate or thrombus formation at high fluid shear stress in flowing blood, including the pathological shear stress that occurs in a sclerotic coronary artery. Our published and preliminary results show how GPIb-dependent interaction of platelets with von Willebrand factor, the major adhesive ligand for GPIb-IX-V, is dependent on the level of shear stress. Using a cross-species (human to canine) homology-swap approach, where human sequence is replaced by the corresponding canine sequence within discrete structural domains, a sequence of GPIb has been identified which becomes increasingly important as hydrodynamic shear stress increases. It is proposed to further define the interactive surface of GPIb that recognizes von Willebrand factor at increasing shear, and to define the relationship between the shear-dependent alteration of GPIb conformation and its ability to interact with other pro-thrombotic or pro-inflammatory binding partners.Read moreRead less
Autoimmune-based thrombocytopenia can be a life-threatening adverse event associated with viral load, surgery, drug therapies or the use of the anticoagulant, heparin. This grant will define mechanisms of anti-platelet antibody-dependent platelet activation and assess shedding of platelet-specific glycoprotein (GP)VI as an immediate consequence of this activation, provide a new strategy for evaluating risk of thrombosis in HIT.
Investigation Of The Proinflammatory Function Of Platelets During Ischaemia-reperfusion Injury
Funder
National Health and Medical Research Council
Funding Amount
$552,720.00
Summary
Platelets are important blood cells that stop bleeding. Platelets also regulate inflammation by modulating the function of white blood cells. Excessive stimulation of white cells by platelets may cause tissue damage relevant to a broad of cardiovascular diseases, including heart disease and stroke. This grant application aims to investigate the precise mechanism by which platelets promote inflammation during a heart attack or stroke.
Microfluidic Device Fo The Quantitative Assessment Of Blood Platelet Aggregation Behaviour
Funder
National Health and Medical Research Council
Funding Amount
$270,114.00
Summary
This project will develop a low-cost microfluidic chip which utilises dynamic shear stress to assess the propensity of blood clotting. This tool will analyze a tiny sample of blood and will predict excessive or ineffective clotting. The project will develop the chip and a low-cost 'chip reader' such that the tool can be operated at the point of care with only basic training.