How Does The Mitochondria Regulate Cardiac L-type Ca2+ Channel Function?
Funder
National Health and Medical Research Council
Funding Amount
$328,267.00
Summary
Oxygen is vital to cellular metabolism and function. Oxygen delivery to cells is critical and a lack of oxygen such as occurs during a heart attack can be lethal. The L-type Ca2+ channel is a protein in the membrane of heart muscle cells responsible for regulating the entry of calcium into heart muscle cells. It plays a role in maintaining the heart beat and contraction. We have found that a lack of oxygen (hypoxia) alters the function of the L-type Ca2+ channel and its response to adrenergic st ....Oxygen is vital to cellular metabolism and function. Oxygen delivery to cells is critical and a lack of oxygen such as occurs during a heart attack can be lethal. The L-type Ca2+ channel is a protein in the membrane of heart muscle cells responsible for regulating the entry of calcium into heart muscle cells. It plays a role in maintaining the heart beat and contraction. We have found that a lack of oxygen (hypoxia) alters the function of the L-type Ca2+ channel and its response to adrenergic stimulation (adrenaline).This may be one of the ways that rhythm disturbances or sudden cardiac death occurs with a heart attack. The activity of the L-type Ca2+ channel is sensitive to changes in reactive oxygen species caused by changes in oxygen concentration. The reactive oxygen species are generated from a part of the cell responsible for maintaining the cell's energy requirements (the mitochondria). Oxidative stress is a feature of various cardiovascular pathologies and we are now interested in determining the effect of oxidative stress on function of the L-type Ca2+ channel and the role of the mitochondria in generating reactive oxygen species. Oxidative stress can damage mitochondria leading to an increase in production of reactive oxygen species. We will determine how oxidative stress damages the mitochondria and how this then alters the channel function, directly or indirectly. The information gained will provide insight into how reactive oxygen species influence L-type Ca2+ channel function and the mechanisms that contribute to pathology involving reactive oxygen species such as heart failure and arrhythmia.Read moreRead less
L-amino Acid Sensing By The Extracellular Calcium-sensing Receptor: Molecular, Cellular And In Vivo Studies
Funder
National Health and Medical Research Council
Funding Amount
$362,545.00
Summary
Recent work by Dr Conigrave and colleagues demonstrates for the first time that protein and calcium metabolism are linked at the molecular level by the widely distributed calcium-sensing receptor. The project will aim to demonstrate the physiological significance of this finding by testing whether L-amino acids, the building blocks of body protein, exert receptor-dependent control over the secretion and blood levels of hormones that regulate body calcium levels. It will further test the hypothes ....Recent work by Dr Conigrave and colleagues demonstrates for the first time that protein and calcium metabolism are linked at the molecular level by the widely distributed calcium-sensing receptor. The project will aim to demonstrate the physiological significance of this finding by testing whether L-amino acids, the building blocks of body protein, exert receptor-dependent control over the secretion and blood levels of hormones that regulate body calcium levels. It will further test the hypothesis by determining whether amino acids exert receptor-dependent control over the proliferation of bone forming cells and urinary excretion of calcium.Read moreRead less
Determining The Cellular Mechanisms Involved In The Airway Response To Topical Citrate
Funder
National Health and Medical Research Council
Funding Amount
$444,491.00
Summary
The air passages of the lungs are lined by mucous membranes. These membranes are covered by a thin layer of fluid to protect the airways from drying. This fluid allows the cilia, the hair like projections on top of the airway cells to beat more effectively to remove mucous and inhaled particles from the lungs. The volume and composition of this fluid is determined by the salt and water movement across the mucous membranes of the airways. These processes are abnormal in cystic fibrosis (CF), the ....The air passages of the lungs are lined by mucous membranes. These membranes are covered by a thin layer of fluid to protect the airways from drying. This fluid allows the cilia, the hair like projections on top of the airway cells to beat more effectively to remove mucous and inhaled particles from the lungs. The volume and composition of this fluid is determined by the salt and water movement across the mucous membranes of the airways. These processes are abnormal in cystic fibrosis (CF), the most common lethal inherited disease affecting Australians. In CF, an abnormal gene disrupts one of the major mechanisms for salt and water movement in the air passages. This abnormal salt transport causes drying of the airway surface which impairs the working of the cilia. This leads to retention of mucous in the airways with repeated bacterial infections damaging the lungs. Over the last 10 years, we have developed a series of simple tests to measure the abnormalities in the CF airway of human subjects. We have isolated an exciting new clinical application for sodium citrate, a substance used in blood transfusions. Citrate appears to alter both the salt transport abnormalities found in CF. This research proposal seeks to better understand the dual effects of citrate and to test similar compounds that may have stronger effects. The ultimate aim of our research is to have sufficient knowledge to work out the best way to develop a new treatment for CF.Read moreRead less