Mitochondrial Iron Overload And Friedreich's Ataxia: The Role Of Frataxin In Iron And Haem Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$285,990.00
Summary
Friedreich's ataxia (FA) is due to the lack of a protein known as frataxin. Recent studies using Baker's yeast have shown that the deletion of frataxin results in the accumulation of toxic iron in the mitochondrion. More recently, a variety of studies have shown that FA patients have iron loading within their cells. The iron build-up may cause severe damage. At present, the role of frataxin in mammalian mitochondrial iron metabolism is unknown. Our preliminary studies demonstrate that frataxin i ....Friedreich's ataxia (FA) is due to the lack of a protein known as frataxin. Recent studies using Baker's yeast have shown that the deletion of frataxin results in the accumulation of toxic iron in the mitochondrion. More recently, a variety of studies have shown that FA patients have iron loading within their cells. The iron build-up may cause severe damage. At present, the role of frataxin in mammalian mitochondrial iron metabolism is unknown. Our preliminary studies demonstrate that frataxin is down-regulated by either erythroid differentiation or the haem precursor protoporphyrin IX (Becker and Richardson, submitted). These data strongly suggest a role for frataxin in iron metabolism. In the present study we will continue to assess if frataxin plays a role in the way cells handle iron. Using a unique model of mitochondrial iron overload developed in my lab (Richardson et al. (1996) BLOOD 87:3477), we will extensively investigate the iron metabolism of the mitochondrion in order to determine the function of frataxin and its role in Friedreich's ataxia. In addition, we have developed a series of new drugs known as iron chelators that can enter the mitochondrion due to their high lipid solubility (Becker and Richardson 1999 J. Lab. Clin. Med. 134:510). These latter drugs are far more effective than the chelator currently used to treat iron overload, desferrioxamine (DFO). Indeed, our chelators have been designed to result in high iron chelation efficacy but low toxicity (see Becker and Richardson, 1999). This exciting research may be crucial in understanding the development of FA and in creating new therapies such as the use of iron chelators.Read moreRead less
Mitochondrial Iron Overload And Friedreich's Ataxia: The Role Of Frataxin In Iron And Haem Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$606,000.00
Summary
Friedreich's ataxia (FA) is due to the lack of a protein known as frataxin. A variety of studies using Baker's yeast and conditional frataxin knockout (KO) mice have shown that deletion of frataxin leads to the accumulation of toxic iron in their mitochondrion. More recently, a variety of studies have shown that FA patients have iron-loading within their mitochondrion. Iron in the highly redox active environment of the mitochondrion could contribute to the generation of cytotoxic radicals that c ....Friedreich's ataxia (FA) is due to the lack of a protein known as frataxin. A variety of studies using Baker's yeast and conditional frataxin knockout (KO) mice have shown that deletion of frataxin leads to the accumulation of toxic iron in their mitochondrion. More recently, a variety of studies have shown that FA patients have iron-loading within their mitochondrion. Iron in the highly redox active environment of the mitochondrion could contribute to the generation of cytotoxic radicals that cause severe damage. Further, cells deficient in frataxin are sensitive to oxidant stress and Fe chelators rescue oxidant-mediated death of cells from FA patients. Indeed, free radical scavengers have shown to be of use in the treatment of this disease. Studies in DR's lab during this NHMRC grant have shown that frataxin is down-regulated by erythroid differentiation or the haem precursor, protoporphyrin IX (BLOOD 2002;99:3813-22). These data indicate a role for frataxin in Fe metabolism and the pathogenesis of FA. In this study we will continue to examine the role of frataxin in the way cells handle Fe using experimental models developed under the current NHMRC grant. These include transfected cell lines with low frataxin expression generated using an expression vector containing anti-sense frataxin cDNA. Further we obtained the frataxin conditional KO mouse and generated a breeding colony. These animals display many of the pathological features of FA and are the best current model of the disease. Indeed, they will be critical for assessing the role of frataxin in Fe metabolism and as a model to test the ability of Fe-binding drugs to prevent the pathology observed. We designed lipid-soluble chelators that can enter the mitochondrion to bind Fe (Biochim Biophys Acta 2001;1536:133-140) and these ligands will be tested to prevent disease progression in the KO mice. This exciting research is crucial for understanding the pathogenesis of FA and in creating new therapies.Read moreRead less
Ocular Motility In Autism And Asperger S Disorder: Dissociation Of Motor Deficits.
Funder
National Health and Medical Research Council
Funding Amount
$131,235.00
Summary
We will use ocular motor technology to investigate motor dysfunction in autism and Asperger's disorder, to advance our understanding of the neurobiological bases of these disorders. This will help clarify whether neural networks are differentially disrupted in these disorders, as our previous clinical research suggests. This dissociation and the subsequent development of an ocular motor clincal screen may improve diagnosis, and potentially treatment, of these devastating conditions.
Motor Functioning In Autism And Asperger's Disorder: Furthering Current Neurobehavioural And Clinical Definitions
Funder
National Health and Medical Research Council
Funding Amount
$354,932.00
Summary
While it is well known that autism and Asperger's disorder are associated with social, communicative, and behavioural symptoms, it is less well known that affected individuals also have considerable movement and coordination difficulties. For example, these children often have problems with hand writing, walking, hopping, skipping, catching, and running. These skills are very important for success at school; for example, if children are unable to participate in school sports they often feel isol ....While it is well known that autism and Asperger's disorder are associated with social, communicative, and behavioural symptoms, it is less well known that affected individuals also have considerable movement and coordination difficulties. For example, these children often have problems with hand writing, walking, hopping, skipping, catching, and running. These skills are very important for success at school; for example, if children are unable to participate in school sports they often feel isolated and rejected from the peer group. Also, hand writing problems have a significant impact on children's academic performance. Our previous research has suggested that there may be particular patterns of motor problems that characterise individuals with autism and Asperger's disorder. Our proposed research aims to use the kinds of 3D motion analysis technology used in the movie industry to capture exactly how people affected by these conditions move and respond to the environment. This study will enable us to highlight particular parts of the brain-motor circuitry that are affected by these disorders and will also enable us to more clearly distinguish how autism is different from Asperger's disorder. Ultimately, it is hoped that our motor investigations will lead to improved assessment and interventions for these disorders.Read moreRead less
Prevalence report by the Australian Advisory Board on Autism Spectrum Disorders (ASD) estimated that 1 child in every 160 children in the 6-12 year-old age group is affected by ASD. There is no cure for ASD and the causes are not understood. We propose that sex hormones may play a role in the development of these disorders. We will test this hypothesis using knockout and transgenic mouse models which have social interaction deficits and brain structure reminiscent of these disorders.
Structure and function of heterodimeric amino acid transporters. Recently a new family of amino acid transporters has been identified, the members of which are involved in the delivery of amino acids between cells and tissues. All members display a rather unusual structure in that they require two subunits to be functional. The main aim of this study is to investigate the interaction between large and small subunits. The study will give insight how membrane proteins form complexes in the membran ....Structure and function of heterodimeric amino acid transporters. Recently a new family of amino acid transporters has been identified, the members of which are involved in the delivery of amino acids between cells and tissues. All members display a rather unusual structure in that they require two subunits to be functional. The main aim of this study is to investigate the interaction between large and small subunits. The study will give insight how membrane proteins form complexes in the membrane and how these interactions affect the function of a complex membrane protein.Read moreRead less
Bioreactors for manufacture of human platelets. Blood cell transfusion is a critical part of medicine that is supported by volunteer donors. Unfortunately, the demand for blood cells for transfusion far outstrips supply and therefore new strategies are required for manufacture of blood cells. This project will lead to the development of technology for manufacture of human platelets from stem cells. The systems devised will be applicable to a broad range of other blood cell types.
Amino acids as nutrients - the molecular basis of amino acid absorption in kidney and intestine. Nutrition is a critical factor for well being and health. This is highlighted by the increase in frequency of type II diabetes and the obesity problem that all societies with a western diet face. Most studies in nutrition focus on fat and carbohydrates because of their direct involvement in obesity and diabetes. Proteins and the resulting peptides and amino acids, however, form 10-15% of our nutritio ....Amino acids as nutrients - the molecular basis of amino acid absorption in kidney and intestine. Nutrition is a critical factor for well being and health. This is highlighted by the increase in frequency of type II diabetes and the obesity problem that all societies with a western diet face. Most studies in nutrition focus on fat and carbohydrates because of their direct involvement in obesity and diabetes. Proteins and the resulting peptides and amino acids, however, form 10-15% of our nutrition. At a time where protein-rich diets are recommended to fight obesity and diabetes, it is important to understand the basis of protein absorption and metabolism. This project investigates the mechanism and mediators of amino acid absorption in kidney and intestine. Read moreRead less
Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0561173
Funder
Australian Research Council
Funding Amount
$207,189.00
Summary
High throughput proteomics - Thermo Finnigan ProteomeX LCQ Integrated Proteomics Workstation. As research in the biological sciences moves into post-genomics era, so attention has focused on the development of technologies capable of characterizing the molecular complexity inherent in the proteome. Recent technical innovations in this field have resulted in the advancement of mass spectrometers that are capable of exemplifying unknown proteins with great efficiency. These new technologies are ....High throughput proteomics - Thermo Finnigan ProteomeX LCQ Integrated Proteomics Workstation. As research in the biological sciences moves into post-genomics era, so attention has focused on the development of technologies capable of characterizing the molecular complexity inherent in the proteome. Recent technical innovations in this field have resulted in the advancement of mass spectrometers that are capable of exemplifying unknown proteins with great efficiency. These new technologies are central to any institution committed to the development of a competitive research nexus in biological sciences. The purpose of this application is to upgrade the mass spectrometry facility at the University of Newcastle such that it is able to provide cutting edge support to the extensive scientific community within the Hunter region.Read moreRead less
Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0453630
Funder
Australian Research Council
Funding Amount
$274,692.00
Summary
High-Speed Confocal Microscope Live Cell Recording System. The high-speed confocal microscope live cell recording system we are establishing represents new generation equipment. It allows quality imaging of selected subcellular regions of live cells combined with simultaneous electrophysiological recording at rates and sensitivity hitherto not possible. This equipment provides a window of opportunity for major research advances in that it allows real-time two and three-dimensional imaging of fun ....High-Speed Confocal Microscope Live Cell Recording System. The high-speed confocal microscope live cell recording system we are establishing represents new generation equipment. It allows quality imaging of selected subcellular regions of live cells combined with simultaneous electrophysiological recording at rates and sensitivity hitherto not possible. This equipment provides a window of opportunity for major research advances in that it allows real-time two and three-dimensional imaging of fundamental cellular activities that previously could not be viewed. It will allow major advances in priority health-related research and will provide an ideal research tool to introduce young scientists and students to cutting edge research.Read moreRead less