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.
I am a developmental biologist using genetic approaches in the model vertebrate, zebrafish, to study the molecular basis for muscle formation. My laboratory studies the basic biology of muscle and applies that knowledge to create accurate disease models o
Advancing Glycine To The Clinic For Duchenne Muscular Dystrophy
Funder
National Health and Medical Research Council
Funding Amount
$248,978.00
Summary
We have identified the therapeutic potential of the amino acid glycine for Duchenne muscular dystrophy (DMD), the most common and severe of the muscular dystrophies. To facilitate rapid translation to the clinic, this proposal will; 1) examine the effect of glycine on lifespan and quality of life in mouse models of DMD; 2) determine glycine’s mode of action; and 3) investigate whether these effects represent further benefits to those currently used gold standard treatments.
Antisense Oligonucleotide Induced Exon Skipping As A Treatment For Duchenne Muscular Dystrophy
Funder
National Health and Medical Research Council
Funding Amount
$363,055.00
Summary
Duchenne muscular dystrophy (DMD) is the most common severe muscle wasting disease that affects boys. A defect in the dystrophin gene (typically a frameshift or nonsense mutation) precludes the synthesis of any functional protein. Becker muscular dystrophy (BMD) is a milder condition that also arises from defects in the dystrophin gene but in these cases, the mutations are usually in-frame deletions that allow some functional protein to be synthesised. There have been significant limitations to ....Duchenne muscular dystrophy (DMD) is the most common severe muscle wasting disease that affects boys. A defect in the dystrophin gene (typically a frameshift or nonsense mutation) precludes the synthesis of any functional protein. Becker muscular dystrophy (BMD) is a milder condition that also arises from defects in the dystrophin gene but in these cases, the mutations are usually in-frame deletions that allow some functional protein to be synthesised. There have been significant limitations to dystrophin gene replacement therapies, due to the nature of the target (muscle fibres) and the size and complexity of the gene. This project will investigate an alternative genetic approach in cells expressing dystrophin (this gene is transcribed and processed differently in a variety cell types), whereby antisense oligonucleotides are used to redirect the processing of dystrophin pre-mRNA in the region of the DMD mutation. Although the DMD mutation would still be present at the gene level, the disease-causing mutation would be removed during the processing of the dystrophin pre-mRNA. Once a nonsense mutation has been removed or the reading frame restored from a DMD transcript, the resultant engineered dystrophin mRNA could be translated into a functional Becker-like protein.Read moreRead less
Optimization Of Splice Switching Therapies To Treat Duchenne Muscular Dystrophy
Funder
National Health and Medical Research Council
Funding Amount
$448,827.00
Summary
Duchenne muscular dystrophy, the most common and serious form of childhood muscle wasting, is caused by mutations in the dystrophin gene that block synthesis of the normal product. Antisense oligomers have been used in clinical trials to remove the disease-causing part of the message and rescue expression. Clinical trials have demonstrated proof-of-concept, although individual responses varied. This application seeks to improve the therapeutic potential of these compounds.
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
Therapeutic Induction Of Dytrophin-positive Revertant Fibres In The Mdx Mouse
Funder
National Health and Medical Research Council
Funding Amount
$454,825.00
Summary
Revertant fibres are low-abundance, dystrophin-positive fibres found in muscle of DMD patients and animal models. These fibres appear to have a selective advantage over dystrophin negative fibres, as they accumulate with age. Characterisation of dystrophin mRNA has identified in-frame transcripts missing multiple exons, which either exclude a nonsense mutation or restore the reading frame around a deletion. We have designed antisense oligonucleotides (AOs) to bind regions flanking the exon conta ....Revertant fibres are low-abundance, dystrophin-positive fibres found in muscle of DMD patients and animal models. These fibres appear to have a selective advantage over dystrophin negative fibres, as they accumulate with age. Characterisation of dystrophin mRNA has identified in-frame transcripts missing multiple exons, which either exclude a nonsense mutation or restore the reading frame around a deletion. We have designed antisense oligonucleotides (AOs) to bind regions flanking the exon containing the dystrophin mutation in the mdx mouse. The AOs interfere with processing of the pre-mRNA to exclude the mutation and allow a slightly shortened dystrophin to be synthesised. The use of AOs to modify RNA processing allows the gene to function under the control of natural regulatory elements. We have shown that AOs can induce dystrophin expression and improve strength in dystrophic (mdx) mouse hindlimb muscles. We aim to improve upon these results by using AOs to block splice sites flanking consecutive exons, in order to induce dystrophin which mimics that of revertant fibres. As most revertant transcripts are missing multiple exons, we believe that the functional capacity of AO-induced dystrophin can be improved upon by removing multiple exons. An mdx mouse skeletal muscle cell line is used for evaluation AOs. However, in order to determine the efficacy of the induced dystrophin in cardiac and skeletal muscle, experiments must be performed on mice. Previous work, in vitro and in muscles of mdx mice have validated this approach. Combinations of AOs which show promise will be delivered by a) intravascular injection b) intraperitoneal injection in mdx mice. The efficacy of the treatment will be assessed by both continual and end point analysis, which includes physiological, clinical, molecular and histological testing. Particular attention will be directed to the well-being of the mice and any adverse side effects which may occur.Read moreRead less
The Role Of Dysferlin In Muscular Dystrophy And Skeletal Muscle Membrane Repair.
Funder
National Health and Medical Research Council
Funding Amount
$316,667.00
Summary
Patients who lack the protein dysferlin have muscular dystrophy. These patients are unable to repair their muscle membranes, which get damaged during normal activities. A defect in membrane repair is a new pathway implicated in the muscular dystrophies, and it is likely that other patients will also have defective muscle membrane repair. We will find out how dysferlin mediates its role in membrane repair, and identify other dysferlin-interacting proteins, as these may also underlie disease.