A Solution To The Parathyroid Gland Secretion Problem
Funder
National Health and Medical Research Council
Funding Amount
$508,003.00
Summary
Parathyroid hormone is the master hormone regulator of whole body calcium metabolism and a powerful new treatment for osteoporosis but the mechanism by which its natural secretion is controlled has never been solved. In this project we will apply new insights and advanced technical approaches to resolve this most fundamental question of calcium homeostasis, namely how parathyroid hormone secretion is controlled.
Molecular Determinants Of Amino Acid-dependent Signalling By The Calcium-sensing Receptor
Funder
National Health and Medical Research Council
Funding Amount
$566,035.00
Summary
Amino acids are the building blocks of proteins and an alternative energy source to carbohydrate and fat. Proteins are major structural components of our bodies. They also fulfil an amazing diversity of cellular and bodily functions acting, for example, as enzymes (biological catalysts), receptors, molecular chaperones and biological machines. Thus, amino acids are key nutrients and the human body has developed mechanisms for tightly regulating cellular responses depending upon their levels in b ....Amino acids are the building blocks of proteins and an alternative energy source to carbohydrate and fat. Proteins are major structural components of our bodies. They also fulfil an amazing diversity of cellular and bodily functions acting, for example, as enzymes (biological catalysts), receptors, molecular chaperones and biological machines. Thus, amino acids are key nutrients and the human body has developed mechanisms for tightly regulating cellular responses depending upon their levels in blood. Identifying amino acid sensing molecules and identifying the mechanisms they use to control cellular responses is thus a key issue in human biology. The applicant identified the calcium-sensing receptor as an amino acid sensor and has shown that this receptor provides a means by which fluctuations in amino acid levels regulate the secretion of the key calcium-regulating hormone, PTH. In the current proposal, the mechanisms that link amino acid activation of the calcium-sensing receptor to its key cellular responses will be determined.Read moreRead less
Does Teriparatide Reverse Osteonecrosis Of The Jaw In Patients With Cancer? A Randomised, Controlled Trial
Funder
National Health and Medical Research Council
Funding Amount
$357,412.00
Summary
Osteonecrosis of the jaw (ONJ) is debilitating and associated with drugs that increase bone strength and reduce the bone remodeling rate (bisphosphonates or denosumab). Up to 15% of patients with bone marrow cancer and 1 out of 952 patients with osteoporosis treated with bisphosphonates may get ONJ. This 8-week trial of subcutaneous teriparatide (a hormone that forms new bone) or placebo injections aims to promote resolution of ONJ, measured clinically and by x-ray, and improve quality of life.
Secretion is an essential step in memory and learning, control of metabolism and reproduction and the functioning of most organs. Secretory dysfunction also underlies many diseases including type 2 diabetes. We plan experiments to test for a new model of control of insulin secretion.
The Role Of Sorting Nexin 27 In Cargo-trafficking During Skeletal Homeostasis
Funder
National Health and Medical Research Council
Funding Amount
$623,327.00
Summary
Skeletal diseases encompass a devastating set of disorders ranging from heritable skeletal dysplasia’s such as dwarfism through to degenerate diseases like osteoporosis. This research project aims to determine the role of a protein called Sorting Nexin 27 (SNX27), normally involved in the transport of intracellular cargo (e.g. growth factor receptors), in the maintenance of the skeleton and its potential contribution to the pathogenesis of skeletal disorders.
Deciphering The Molecular Steps Leading To The Potentiation Of Neuronal Exocytosis By Arachidonic Acid
Funder
National Health and Medical Research Council
Funding Amount
$273,000.00
Summary
Release of hormones and neurotransmitters relies on a process called exocytosis which involves SNARE proteins: syntaxin1A and SNAP-25 on the target plasma membrane and VAMP on the vesicular membrane. Availability of the t-SNARE on the plasma membrane is believed to play a major role in controlling the amount of exocytosis. Syntaxin1A bound to Munc18 constitute an 'unproductive-reserve' pool of closed Syntaxin that cannot interact with SNAP-25. Intracellular messengers capable of releasing Syntax ....Release of hormones and neurotransmitters relies on a process called exocytosis which involves SNARE proteins: syntaxin1A and SNAP-25 on the target plasma membrane and VAMP on the vesicular membrane. Availability of the t-SNARE on the plasma membrane is believed to play a major role in controlling the amount of exocytosis. Syntaxin1A bound to Munc18 constitute an 'unproductive-reserve' pool of closed Syntaxin that cannot interact with SNAP-25. Intracellular messengers capable of releasing Syntaxin1A from Munc18 thereby making it available to interact with SNAP-25, are foreseen to play a major role in potentiating exocytosis - a process with ramification for memory and learning. We have identified arachidonic acid, a lipidic messenger which fullfil this role. For the first time we are in a position to manipulate at the molecular level different pools of SNARE proteins with direct implications for our understanding of the mechanism of secretion. Very few models are currently available to understand how learning and memory occur in the brain. Our research points to a new direction: the amount of 'active' and 'unproductive-reserve' pools of SNARE proteins present on the plasma membrane of neurosecretory cells are in dynamic equilibrium and arachidonic acid, a second messenger capable of trans-synaptic action, can modify this equilibrium resulting in an increase of the amount of 'active' SNARE thereby potentiating the amount of transmitter-hormone released by exocytosis. Importantly, this research lays the basis for a dynamic view of the secretory mechanism with important implications for treatment of diseases such as diabetes and neurodegenerative diseases. Our hope is that by understanding at the molecular level how secretory cells regulate the amount of their secretion, we will be in a position to modify these parameters in order to counteract illnesses of the nervous system.Read moreRead less