DNC - Dubowitz Neuromuscular Centre

The Centre is directed by Prof Francesco Muntoni.

The goals of our research are to:

1. Elucidate the genetic and the molecular basis of a group of diseases called congenital muscular dystrophies and congenital myopathies.

2. Modify splicing in Duchenne muscular dystrophy and spinal muscular atrophy using antisense oligonucleotides.

3. Characterize muscle stem cells for possible future therapeutic applications.

4. Determine how cell adhesion proteins regulate muscle development and disease.

1. Molecular basis of congenital muscular dystrophies and congenital myopathies

Our group has identified several novel loci for forms of congenital muscular dystrophy and congenital myopathies. In 2001 we identified mutations in the FKRP gene in a CMD variant called MDC1C [link to NCG centre with the leaflets]; shortly after we discovered that milder mutations in the same gene were also responsible for one of the most common forms of limb girdle muscular dystrophy (LGMD2I). In a few children with severe MDC1C there is evidence of brain involvement. Mutations in FKRP identified a novel pathway responsible for both muscular degeneration and neuronal migration defects, aspects which are being further characterised in a relevant knock-in animal model, produced in collaboration with Dr Susan Brown. Our group contributed in 2011 to the identification of mutations in DAG1 in a novel form of muscular dystrophy.

In 2005 we discovered that mutations in the human LARGE gene cause MDC1D, another form of congenital muscular dystrophy. We have shown that overexepression of this gene can restore normal dystroglycan ligand binding in cells from patients with a dystroglycanopathy. Upregulation of LARGE expression appears to be a plausible therapeutic approach in these disorders and to explore this further we have generated and characterised several transgenic lines (in collaboration with Prof Nic Wells and Dr Sue Brown) expressing a LARGE transgene. We have published in 2010 that this approach is safe and effective in inducing dystroglycan hyperglycosylation; we are currently assessing the effect of this transgene in rescuing the phenotype in fkrp and pomgnt1 deficient dystrophic animals. Finally we have set up a high throughput for assessing hyperglycosylation in a cellular model and are currently exploring efficacy of a drug library with an industrial partner.

2. Regulation of splicing

We work on regulating splicing of the SMN2 gene in spinal muscular atrophy; and in antisense oligonucleotide induced exon skipping in Duchenne muscular dystrophy. This latter interest culminated in a Department of Health funded grant to establish a consortium for a phase I/II therapeutic trial of antisense oligonucleotides in Duchenne muscular dystrophy that started in 2005 MDEX consortium, www.mdex.org.uk, of which Prof Muntoni is the Principal Investigator). In view of the exciting data generated by this project, we have subsequently obtained an MRC translational research grant to extend this study into a repeated intravenous antisense administration into young boys with Duchenne. This study, performed in partnership with the biotech company AVI BioPharma, has been recently completed and the results indicate that indeed the repeated administration of the morpholino antisense oligomer AVI-4658 was well tolerated and capable of restoring dystrophin expression in a dose response fashion in treated boys (visit www.mdex.org.uk for further information).

The work on spinal muscular atrophy is performed in collaboration with Prof Ian Eperon, Leicester University. We have devised a novel approach (tailed oligonucleotides or TOES), to induce exon INCLUSION in the SMN2 gene. We are recently identified a lead compound that could have potential therapeutic applications.

3. Muscle stem cells

Dr. Jennifer Morgan is the principal investigator of this line of research. Her main areas of interest are the identification of progenitor cell types that contribute to skeletal muscle regeneration, the genetic and functional manipulation of these cell populations to enhance muscle repair.

Her recent work provided clear evidence that a sub-population of satellite cells are functional stem cells, giving rise both to skeletal muscle and reconstituting the satellite cell population. These satellite cells of donor origin are functional, as they are able to contribute to new regenerated skeletal muscle fibres following injury. The ability of other stem cells to regenerate skeletal muscle and reconstitute the satellite cell pool are being explored, as well as the genetic modification of such stem cells to produce dystrophin protein in regenerated muscle fibres.

She is currently exploring ways of identifying and isolating the ?stem? satellite cells and other stem cell populations that contribute efficiently to skeletal muscle regeneration.

Prof. Muntoni and Dr Morgan work in collaboration on various aspects of muscle stem cells with the long-term aim of assessing the feasibility of therapeutic intervention using muscle stem cells.

4. Cell adhesion proteins in skeletal muscle development and disease

The principal investigator of this line of research is Dr Francesco Conti. Integrins are a major class of adhesion proteins in muscle that mediate a connection between extracellular matrix proteins and cytoskeletal and signaling proteins in the cytoplasm. Integrins have been shown to regulate myoblast fusion, assembly of the cytoskeleton, and mutations in integrins and associate proteins have been associated with muscular dystrophy and dilated cardiomyopathy. In our lab, we are interested in studying the molecular mechanisms by which these processes are regulated.

In addition, we are currently developing a preclinical model to correct glycosilation defects in the DPC, which lead to severe forms of muscular dystrophy. We are emploting a novel type of gene therapy called RNA trans-splicing. This is part of a collaborative project with the groups of Luis Garcia and Thomas Voit at the Institute of myology in Paris, France.