What is the objective of this research project?
Our initial objective was to characterize the secreted proteome or “secretome” of differentiating human myoblasts thus mimicking the behaviour of cells entering the process of muscle fibre regeneration. Secreted signalling molecules including growth factors and cytokines have been shown to regulate activation, proliferation and differentiation of the muscle progenitors known as satellite cells. Therefore they must serve important functions during skeletal muscle development, maintenance and repair.
In order to do this, we used a proteomic approach with the latest developments in mass spectrometry. This was done in collaboration with Professor Ole Jensen, from the Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark.

 

What results did you obtain?
We identified 965 non-redundant proteins secreted by human muscle cells. Among those, 257 proteins (27%) were secreted in the extracellular space via the classical ER/Golgi secretion pathway, 85 of which were extracellular matrix components. Several known secreted proteins such as Galectin-1, IGF-II and myostatin were also identified.
In addition to these extracellular “soluble” secreted proteins, 708 intracellular proteins from various origins (membrane, cytosolic, Golgi/ER, mitochondrial, nuclear, etc) were found in the conditioned medium of differentiating myoblasts.

A research team at the Western Australian Institute for Medical Research (WAIMR) has successfully treated mice with a severe muscle disease that causes floppy baby syndrome, a congenital myopathy disorder that causes babies to be born without the ability to properly use their muscles. Most babies born with the rare disorder are severely paralysed and most die before the age of one. Some babies develop the syndrome because they are missing a protein called skeletal muscle actin. It is key to allowing muscles to contract, but children with this disease have mutations of the gene and so the protein is not produced. Heart actin is found in skeletal muscles while the baby is developing in the womb, but has almost completely disappeared by birth. However, the team had previously observed a number of children who, despite having no skeletal muscle actin in their skeletal muscle due to their genetic mutation, were not totally paralysed at birth. Further studies revealed that heart actin, another form of the protein, was abnormally “switched on” in their skeletal muscles. This led them to investigate whether heart actin could be used to treat skeletal muscle actin disease. Using genetic techniques, the research team reactivated the heart actin after birth in place of skeletal muscle actin, reversing the effects of the congenital myopathy. The mice with floppy baby syndrome were only expected to live for nine days. However, 93.5% survived more than three months, and some more than two years. Their locomotor performance was comparable to normal mice, as was their overall muscle strength, and their endurance was actually higher, they ran faster and for longer.

 These findings now need to be applied to human patients. The researchers are currently screening more than a thousand already-approved medications for one that might increase heart actin in skeletal muscles, which could potentially offer a treatment for many patients.

 

A new and exciting study suggests that adult stem cells, not embryonic stem cells, are appropriate for use in therapies for repairing damaged and diseased muscle. Christoph Lepper and colleagues at the Carnegie Institute’s Department of Embryology in Baltimore report that experiments with mice show the genes involved in muscle development are turned off soon after birth, and are not used by adult stem cells that repair muscle damage. Earlier studies have shown that two genes - Pax3 and Pax7 - control cells that give rise to muscle in embryos, and Pax7 also helps build muscle in newborn mice. To get a better understanding of their function, the authors studied these genes at various stages of development in mice. Both the Pax3 and Pax7 genes were inactivated in adult muscle stem cells but the adult stem cells were still able to function normally. The authors then looked at whether the same was true in injured muscles, when muscle stem cells become activated to repair muscle tissue. Mouse leg muscles were thus injured and the muscle stem cells were able to make new muscle, even in the absence of the two key embryonic muscle stem cell genes. It is believed that the embryonic muscle cell genes appear to be active only in mice within the first three weeks after birth. After that, the genes become quiescent and allow a different set of genes to take over. Finding those genes will be important as scientists pursue new treatments for diseases like muscular dystrophy. Other stem cell types should be investigated to see how age might affect their properties, and the age of stem cells should be considered for transplant-based treatments. The data imply that studying embryonic stem cells is an inadequate substitute for directly studying how adult stem cells carry out their normal repair functions in the body, and embryonic stem cells themselves are inadequate substitutes for adult stem cells in medical therapies. This unexpected result demonstrates that “the quest for the perfect cell to cure the multitude of serious degenerative diseases is far from over”.

 

Bethlem Myopathy and Ullrich Congenital Muscular Dystrophy (UCMD) are muscle-wasting diseases caused by deficiencies in collagen VI, a component of connective tissue. Patients are usually diagnosed at birth and suffer from muscle weakness that worsens over time. UCMD patients often also suffer respiratory failure, which is complicated by lung infections. Although the drug cyclosporin A (CsA) offers some benefit for these patients, its long-term use may be undesirable because it interacts with calcineurin, an important immunoregulatory protein, thus exposing patients to potentially harmful immunosuppression. In this study, Tania Tiepolo, of the University of Padova in Italy, and colleagues assessed the effects of a new drug called Debio 025 in a mouse model of collagen VI muscular dystrophies. After just five days treatment with Debio 025, both intraperitoneal and oral administration prevented mitochondrial dysfunction and normalized the apoptotic rates and ultrastructural lesions in the treated mice. Debio 025 showed great potential for slowing the progression of the muscle wasting disease. More importantly, unlike cyclosporine A, Debio 025 did not display affinity for calcineurin and therefore lacks immunosuppressive activity, making it suitable for long-term use. This implies that Debio 025 may provide a safer alternative to CsA in muscular dystrophy. These findings provide an important proof of principle that collagen VI muscular dystrophies can be treated with Debio 025 and represents an essential step towards an effective therapy for Ullrich Congenital Muscular Dystrophy and Bethlem Myopathy because Debio 025 does not expose patients to the potentially harmful effects of immunosuppression.

 

> For more information
Deadline for registration : 31st July 2009
Deadline for abstracts : 28th August 2009

Deadline abstracts: 15th August 2009    
Deadline early registration: 15th September 2009

> Contact : andoni.urtizberea(a)hnd.aphp.fr

Inauguration of the Pitié-Salpêtrière (AP-HP) Biological Resource Platform

On 25 June 2009, the Plateforme de Ressources Biologiques (PRB or Biological Resource Platform) at Pitié-Salpêtrière Hospital in Paris will be inaugurated. This new platform brings together several biobanks under the same roof: Myobank, the muscle tissue bank created by the Institut de Myologie-AFM (Myology Institute - French Muscular Dystrophy Association), the NeuroCEB EIG, a tissue bank for research into neurodegenerative diseases, and the tumour and brain tissue banks collected by AP-HP (the Public Health Organisation serving Paris). The aim is to stimulate biomedical research by providing both French and foreign research scientists with a very broad range of human biological material samples, as along with the corresponding clinical, biological and genetic information.

Each chapter of this book shows what is rarely, if ever, done in scientific papers: how the problems truly arose; how the methods came about; the curious collaborators involved; the twists and turns of thought involved in the stories; the solutions that have so far appeared; and the surprising new ideas that stem from the work. In particular, the part played by serendipity becomes ever more evident. Research is very often a kind of “Alice-in-Wonderland” task, and both students and the public alike are fascinated by the inside stories of how discoveries are really made. It is precisely this excitement and complexity that is presented in this book.

This book provides an authoritative overview of the global development of surgical paediatrics. The compendium acknowledges the enormous contribution of imaging (ultrasound/MRI and PET scans), minimal invasive surgery, and fetal surgery, as well as the role of related journals and associations, in the progress of surgical paediatrics. Many of the contributors have been instrumental to the development of surgical paediatrics in their respective countries, and have considerable worldwide influence on the management of children requiring surgical care. Through their valuable insight and first-hand experience, this book not only shines a light on the past achievements of previous generations of paediatric surgeons, but also serves as a model to encourage future generations to do likewise. 

Research Associate : University of Virginia Department of Pathology, Charlottesville, VA
The Department of Pathology at University of Virginia Health Systems is seeking applications for two Research Associate positions. The positions are available immediately for individuals with Ph.D, M.D. or M.D./Ph.D. to study molecular mechanisms underlying the pathogenesis of myotonic muscular dystrophy (DM). Areas of research include post-transcriptional gene regulations, RNA biology, muscle/cardiac development and mouse genetics. The laboratory utilizes molecular techniques, cell biology and transgenic mouse models to address various aspects of DM. A background in rodent genetics , and/or experience in molecular and cell biology with an interest in human disease are essential. Experience in small animal techniques such as embryo harvests, EMG/ECG, in-situ, hybridization and histology would be an asset.
For questions, please contact Mani Mahadevan @ 434-243-4816 or msm8r(a)virginia.edu.
Applicants must apply at http://jobs.virginia.edu.
Search on posting number 0603457; then, complete a Candidate Profile online and attach a curriculum vitae and contact information for three references.

The bimonthly Newsletter of the Institute of Myology keeps you up to date with developments in myology research, and presents a summary of the latest scientific, medical, political and associative news concerning neuromuscular diseases.

You can access our Newsletter by connecting directly to the Institute of Myology website, or by subscribing.

 

If you would prefer to receive this Newsletter in French, please click here.