Peptide Conjugates Of Splice-correcting Oligonucleotides For Enhanced In Vitro And In Vivo Delivery For Neuromuscular Disease Therapy.
Funder
National Health and Medical Research Council
Funding Amount
$332,347.00
Summary
Currently, there is no known cure for certain neuromuscular genetic disorders. However, recently identified synthetic DNA-type biomolecules have shown promising results in reversing such diseases in mice. These biomolecules cannot easily enter the cells in high enough quantity to elicit their beneficial effects. Therefore, this project will aim at identifying novel vecotrs that, when coupled to these biomolecules, are capable of delivering them into specific cell types as well as into the brain.
Molecular Reorganization During K+ Channel Gating: Determination Of Alternate Pore Configurations By X-ray Diffraction.
Funder
National Health and Medical Research Council
Funding Amount
$489,000.00
Summary
Ion channels are specialised pores that control the flow of charge across cell membranes. They have electrical activity, measurable as current. Potassium channels allow only potassium ions to transit the cell membrane to the exclusion of all others. Without potassium channels our nerves, heart, and other organs, would not function. The channels regulate ion flow by an innate ability to open and close at the behest of specific biological signals, and switch easily between physiological states. In ....Ion channels are specialised pores that control the flow of charge across cell membranes. They have electrical activity, measurable as current. Potassium channels allow only potassium ions to transit the cell membrane to the exclusion of all others. Without potassium channels our nerves, heart, and other organs, would not function. The channels regulate ion flow by an innate ability to open and close at the behest of specific biological signals, and switch easily between physiological states. Influencing factors include depolarising pulses and small molecules that bind to their surface, causing the pore to unblock. Hundreds of types of potassium channel, receptive to a variety of cues, exist in man. The architecture of the pore has recently been confirmed, in the form of three-dimensional models of four quite different channels. This has been invaluable in elucidating aspects of ion permeation. It has not, however, satisfactorily explained what causes the pore to open and close, how it does so, and if this mechanism is general to all potassium channels. Complementary models of the same potassium channel would permit a direct comparison of structural features. Only then can one verify the molecular rearrangements accompanying opening. The experimental aim of this project is to acquire such information using X-ray crystallographic methods. An expedient approach is to tackle one of the four channels already crystallised, capturing its alternate configuration. Although this is an ambitious plan, it has the potential to be highly rewarding. It is also of unparalleled scientific interest, if the current level of debate in biophysics circles is anything to go by. A high proportion of the world s pharmaceuticals are directed at ion channels, as numerous diseases have been ascribed to compromised potassium channel activity. Our research outcomes will provide a fresh basis for the rational design of new drug therapies.Read moreRead less
Regulation Of The Sarcolemmal Na-K Pump By FXYD Proteins
Funder
National Health and Medical Research Council
Funding Amount
$268,264.00
Summary
Background. Pump molecules embedded in the membranes of all cells maintain a difference in composition between the cell content and the surrounding tissue fluids. Of these, the membrane sodium-potassium pump (Na+-K+ pump) is the most important. It uses metabolic energy generated in the cell to transport 3Na+ out in exchange for 2K+ transported in, and maintains a low concentration of Na+ and a high concentration of K+ within cells. The opposite applies to the surrounding tissue fluids. The conce ....Background. Pump molecules embedded in the membranes of all cells maintain a difference in composition between the cell content and the surrounding tissue fluids. Of these, the membrane sodium-potassium pump (Na+-K+ pump) is the most important. It uses metabolic energy generated in the cell to transport 3Na+ out in exchange for 2K+ transported in, and maintains a low concentration of Na+ and a high concentration of K+ within cells. The opposite applies to the surrounding tissue fluids. The concentration gradient for Na+ serves in mechanisms that couple transport of other ions and molecules to the downhill movement of Na+ in the direction determined by its concentration gradient. The transport of ions and molecules directly and indirectly due to the operation of the membrane Na+-K+ pump is very important for the function of all cells. Objectives. It is poorly understood how cells regulate the activity of their membrane Na+-K+ pumps. We will examine if small molecules (FXYD proteins) in the cell membrane, closely associated with the pump, regulate its activity. Methods. We will use a whole-cell patch clamping technique to attach small glass pipettes to single heart cells and replace their content with solutions in the pipettes. The technique allows real-time measurement of Na+-K+ pump activity because the 3:2 Na+:K+ exchange ratio generates an electrical current that can be measured in the single cells. The FXYD proteins will be produced in bacteria, purified and introduced into the heart cells by inclusion in the pipette solution that replace the cell content. Expected outcomes. Achieving this project's objectives will greatly enhance our understanding of Na+-K+ pump regulation. This is important because high levels of Na+ in heart cells is a pivotal abnormality in heart disease. Understanding the Na+-K+ pump can be activated to reduce cell Na+ levels should help design of treatments.Read moreRead less
CBS Domain Modulation Of Muscle Chloride Channels; Molecular Mechanism And Physiological Role.
Funder
National Health and Medical Research Council
Funding Amount
$523,455.00
Summary
Muscle chloride channels regulate how readily muscles are activated, particularly during muscle fatigue. Recently we have identified a feed-back mechanism linking chloride channel function to muscle acidosis and energy depletion, key factors in fatigue. Here we will investigate the molecular details of this mechanism and its role in muscle physiology and fatigue. This mechanism may present a future target for the treatment of myotonia, a condition where muscles are too readily activated.
DHPR ? Subunit Binding To A Variably Spliced Region Of RyR1: A Role In EC Coupling And Myotonic Dystrophy
Funder
National Health and Medical Research Council
Funding Amount
$555,892.00
Summary
We have uncovered a communication pathway between two ion channel molecules in muscle cells that underlies human movement. The pathway is critical in normal mobility and is disrupted in myotonic dystrophy. We will study the molecular components of this pathway to understand normal body function and abnormal function in mytotonic dystrophy. The work will facilitate the design of drugs to relieve the mytotonic dystrophy myopathy and form new and much needed class of specific muscle relaxants.
Characteristics Of Splice Variants Of The Skeletal Muscle Ryanodine Receptor: Implications For Myotonic Dystrophy
Funder
National Health and Medical Research Council
Funding Amount
$258,000.00
Summary
The project is to address some of the basic molecular changes that occur in skeletal muscle during development and in myotonic dystrophy. Myotonic dystrophy is a significant health issue since it is the most common adult muscular dystrophy, with an occurrence of ~1 in 7000. The results will provide much needed information about the membrane-associated molecular mechanisms that regulate muscle contraction and may provide a basis for drug design and treatment of myotonic dystrophy. Respiration and ....The project is to address some of the basic molecular changes that occur in skeletal muscle during development and in myotonic dystrophy. Myotonic dystrophy is a significant health issue since it is the most common adult muscular dystrophy, with an occurrence of ~1 in 7000. The results will provide much needed information about the membrane-associated molecular mechanisms that regulate muscle contraction and may provide a basis for drug design and treatment of myotonic dystrophy. Respiration and locomotion depend on the release of calcium ions from stores inside muscle cells. Ryanodine receptor calcium channels regulate calcium release from the stores. The essential nature of ryanodine receptors is underlined by death at or before birth when ryanodine receptor expression is defective. In addition genetic defects in the ryanodine receptor cause cardiac arrhythmias, malignant hyperthermia and central core disease. Ryanodine receptor function is compromised in heart failure and fatigue. The essential role of ryanodine receptors makes them a potential therapeutic target, but they are not used in this way because of our limited knowledge of the protein. Myotonic dystrophy is an autosomal dominant multi-system disorder, in which an expansion of non-coding DNA leads to changes in expression of several different proteins. Although the genetic basis of myotonic dystrophy is now reasonably well understood, the contribution of molecular changes in the affected proteins to the myopathy has not been investigated. Our group has recently discovered that the juvenile form of the ryanodine receptor protein is highly expressed in adults suffering from myotonic dystrophy. By discovering more about the properties of the juvenile isoform, we will understand more about the basic mechanisms of ryanodine receptor function in developing muscle and in myotonic dystrophy and be able to design drugs to specifically modify ryanodine receptor activity.Read moreRead less
Defintion Of Dystrophin Functional Domains According To Exon Boundaries To Optimise Splice Switching Therapies For DMD
Funder
National Health and Medical Research Council
Funding Amount
$520,765.00
Summary
Duchenne muscular dystrophy is a relentlessly progressive muscle wasting disorder, with a predictable outcome and no effective treatment. Splice manipulation has the potential to reduce the severity of the disease, improve the quality of life for patients and reduce health care costs. The definition of dystrophin functional domains according to exon boundaries will allow the most effective treatment strategies for each mutation to be developed.