Targeting To Mitochondria Of Tail-Anchored Proteins. Defining The Molecular Apparatus Of Targeting.
Funder
National Health and Medical Research Council
Funding Amount
$254,751.00
Summary
The cells of the body have an intricate and dynamic internal architecture, with the components (proteins, lipids, and nucleic acids) of the cell carefully arranged. It is widely viewed that just how each component finds its place in the cell, the cellular adressing system, is of critical importance. This was recognized this year by the award of the Nobel Prize in Medicine to Dr. Gunter Blobel for his work on the signals that direct different proteins to their correct destination. One such destin ....The cells of the body have an intricate and dynamic internal architecture, with the components (proteins, lipids, and nucleic acids) of the cell carefully arranged. It is widely viewed that just how each component finds its place in the cell, the cellular adressing system, is of critical importance. This was recognized this year by the award of the Nobel Prize in Medicine to Dr. Gunter Blobel for his work on the signals that direct different proteins to their correct destination. One such destination is the mitochnondria, the particles in the cell that produce chemical energy. The work in this proposal is designed to define precisely the molecular apparatus that targets a group of proteins to mitochondria. This group, proteins that are inserted into the mitochondria at one end of the protein, includes a variety of critical proteins, including those that determine the life or death of a cell. We will define both the address contained within those proteins, and the machinery on the mitochondria that recognizes that address, and ensures that those proteins will become part of the mitochondria. This research has two applications. By understanding the address, we will be able to decode the vast amount genomic data that is being produced, to predict exactly which proteins are delivered to mitochondria. Secondly, by understanding the targeting machinery, we may begin to design molecules that can inhibit its function, and thus manipulate the delivery of those proteins that affect cell life and death.Read moreRead less
A Novel Mechanism For Intestinal Propulsion: Transit Without Neurons Or Pacemakers
Funder
National Health and Medical Research Council
Funding Amount
$256,973.00
Summary
A significant complication of premature births is that the mechanisms that regulate normal intestinal movements have not yet fully developed. We have recently identified a novel pattern of contraction that is seen predominantly in the colon of mice that have not yet developed either the normal nerve circuits that control gut movement and also lack the pacemaker cells that are intrinsic to the muscle coat. This motor pattern appears to be responsible for the movement of gut content during the dev ....A significant complication of premature births is that the mechanisms that regulate normal intestinal movements have not yet fully developed. We have recently identified a novel pattern of contraction that is seen predominantly in the colon of mice that have not yet developed either the normal nerve circuits that control gut movement and also lack the pacemaker cells that are intrinsic to the muscle coat. This motor pattern appears to be responsible for the movement of gut content during the development and maturation of the nerve circuits that regulate this process in more adult animals. However, the mechanisms responsible for this process have not been identified. This project is directed at identifying these mechanismsRead moreRead less
Mechanisms Regulating Nutrient Induced Motor Patterns In The Isolated Small Intestine
Funder
National Health and Medical Research Council
Funding Amount
$427,750.00
Summary
The movements of the small intestine are essential for the digestion and absorption of a meal and consist of two basic patterns during a 3-4 hour period after a meal. These are mixing (or segmentation) and propulsion (or peristalsis). Although it is the subject of ongoing study, much is known about the basic mechanisms that control propulsion, largely because this behaviour is readily seen in isolated segments of gut so it is possible to undertake highly controlled experiments to identify the va ....The movements of the small intestine are essential for the digestion and absorption of a meal and consist of two basic patterns during a 3-4 hour period after a meal. These are mixing (or segmentation) and propulsion (or peristalsis). Although it is the subject of ongoing study, much is known about the basic mechanisms that control propulsion, largely because this behaviour is readily seen in isolated segments of gut so it is possible to undertake highly controlled experiments to identify the various cellular components of the system. By contrast, mixing has only been reliably seen in intact animals making studies of the detailed mechanisms responsible for this behaviour much more difficult. What is known is that the composition of a meal controls the relative amount of mixing and propulsion seen at any location along the small intestine. We have recently identified a pattern of contractions in isolated small intestine (duodenum and-or jejunum) that is induced by the presence of a nutrient in the intestine and appears very similar to the mixing behaviour seen in the intact animal. We have shown that this pattern depends on the activity of nerve cells including those that excite the gut muscle and that it depends on the activity of a hormone released from the lining of the gut wall by fats and other nutrients. The aims of this proposal are to identify how nutrients interact to produce this pattern of contractions, the relative roles of specific types of nerve cells and the sites at which the local hormones released by nutrients act. This is important because increasing the proportion of mixing to propulsion enhances the absorption of nutrient from a meal, so if the mechanisms that initiate mixing behaviour can be regulated in a predictable way by specific nutrient, absorption can be enhanced in various malabsorption syndromes.Read moreRead less
Intestinal Adaptation Following Massive Small Intestinal Resection: Mechanisms And Management
Funder
National Health and Medical Research Council
Funding Amount
$256,980.00
Summary
Short bowel syndrome (SBS) remains a major clinical problem in paediatric and adult clinical practice. The Department of Gastroenterology and Clinical Nutrition at the Royal Children's Hospital has gained recognition as a national centre of excellence for the management of infants and children with SBS and intestinal failure. Due to the significant personal and heath-care burden related to SBS there has been an urgent need to improve understanding about the process of intestinal adaptation follo ....Short bowel syndrome (SBS) remains a major clinical problem in paediatric and adult clinical practice. The Department of Gastroenterology and Clinical Nutrition at the Royal Children's Hospital has gained recognition as a national centre of excellence for the management of infants and children with SBS and intestinal failure. Due to the significant personal and heath-care burden related to SBS there has been an urgent need to improve understanding about the process of intestinal adaptation following massive small bowel resection (MSBR) in order to develop new treatments aimed at improving clinical outcome for patients with SBS. Over the past 5 years we have developed a preclinical model for the study of intestinal adaptation in infants using the juvenile pig. Our recent studies in this model have revealed that elemental formula is inferior to whole protein formula suggesting that the current clinical recommendations need urgent re-evaluation. Using the preclinical model in this proposal, we aim to define the mechanisms underlying the adaptive response and evaluate novel therapies aimed at enhancing adaptation following MSBR. Supplementation of enteral feeds with bovine colostrum isolate resulted in normal growth in the preclinical model despite MSBR. In this proposal we plan to advance this observation for the first time to human clinical trials in infants with SBS. Even small gains in enteral tolerance during the early post-operative period may have a significant impact on morbidity and mortality of children with SBS due to parenteral-nutrition related liver disease and gut-related sepsis. This research proposal provides a unique link between studies aimed at providing the scientific basis for understanding the mechanisms of intestinal adaptation using an established preclinical model and translating the results of these studies onto human trials, taking advantage of the clinical expertise available in the management of children with SBS.Read moreRead less
Targeted Corrective Gene Conversion (TCGC): Application In DMD Mutations And Delivery To Dystrophic (mdx) Muscle
Funder
National Health and Medical Research Council
Funding Amount
$496,500.00
Summary
The muscular dystrophies are inherited diseases that lead to muscle wastage and severe disabilities. The most severe forms result in the early death of newborns, but a large number are diagnosed in children showing early mild symptoms and progress steadily to severe disabling forms in the juvenile and young adult. Perhaps the most devastating of these dystrophies is Duchenne Muscular Dystrophy (DMD). This condition affects 1 in 3,300 boys, who show symptoms at around 5 years of age until wheelch ....The muscular dystrophies are inherited diseases that lead to muscle wastage and severe disabilities. The most severe forms result in the early death of newborns, but a large number are diagnosed in children showing early mild symptoms and progress steadily to severe disabling forms in the juvenile and young adult. Perhaps the most devastating of these dystrophies is Duchenne Muscular Dystrophy (DMD). This condition affects 1 in 3,300 boys, who show symptoms at around 5 years of age until wheelchair confinement by early teens. DMD boys undergo major clinical and surgical treatments which at present only provide small but significant improvements to their lives. The median age at death for Duchenne boys is 22 years. The cause of DMD has been known for almost 2 decades and is a defect in just a single component of muscle, Dystrophin which is produced by muscle cells. In general, boys with DMD possess Dystrophin which is missing an important part that prevents the breakdown of muscles during activity. As a consequence, all the muscles in DMD boys slowly break down over their lifetime until they die because the muscle which helps in drawing breath (Diaphragm) is no longer capable of helping them to breathe. The muscle component Dystrophin is produced by a gene (the dys gene) and the defect of Dystrophin is caused by a defect in the dys gene. If the dys gene defect was able to be corrected in boys with DMD, their Dystrophin may also be corrected and the breakdown of their muscle prevented. We have been able to correct the dys gene in muscle cells from a mouse with DMD. We wish to improve this technology and allow muscle to be corrected with genetically corrected fibres to form a basis for treatment of human DMD. In this way we hope to significantly improve and lengthen these boys' lives and even lead to a cure for DMD and other genetic muscle diseaseRead moreRead less