Kurt Beam, professor of physiology and biophysics at the University of Colorado at Denver, was awarded an MDA research grant totaling $300,000 over a period of three years to study two proteins that, when they malfunction, cause central core disease (CCD).

Muscle contraction in response to a nerve signal involves the interaction of two proteins: the dihydropyridine receptor (DHPR), which “senses” the electrical signal, and the ryanodine receptor (RyR1), which controls the release of calcium ions. Mutations in either one lead to CCD, as well as other muscle disorders. Beam will introduce the genes for these proteins into mouse muscle and nonmuscle cells. For both cell types, he says, researchers will measure the tiny electrical currents (less than a billionth of an ampere) produced by the DHPR. Fluorescence microscopy and calcium indicator dyes will be used to monitor movements of calcium inside individual cells; and confocal microscopy used to determine whether DHPRs and RyR1s are close to one another in the cells. The structure of these proteins then will be analyzed at a higher resolution by means of electron microscopy.

“Using these techniques, we hope to identify exactly what parts of the two proteins touch one another,” and how these sites of interaction and the overall shapes of the two proteins are affected by disease-causing mutations, Beam says.

“Although we have known for upward of 20 years that the DHPR and RyR1 are crucial for muscle contraction, we still do not understand the mechanism of their interaction, or exactly how disease-causing mutations affect this interaction,” says Beam. His research will attempt to better understand those interactions in order to define possible therapeutic targets for CCD and related muscle diseases.

Funding for this MDA grant began August 1, 2013.

Carmen Bertoni, assistant professor of neurology at the University of California, Los Angeles, was awarded an MDA research grant totaling $300,000 over a period of three years to advance gene-editing strategies forDuchenne muscular dystrophy (DMD).

DMD is caused by a mutation in the dystrophin gene. Standard gene therapy techniques have focused on supplying an unmutated dystrophin gene to muscle cells. An alternative strategy, called gene editing, seeks to correct the mutant gene itself.

“Our research group [with MDA funding] has pioneered the use of gene editing strategies for the dystrophin gene to permanently correct the DNA,” Bertoni says.

The gene-editing toolkit is growing, and in this project, Bertoni will compare the correction efficiency of two different methods. Both specifically target the mutant sequence in the gene, and harness elements of the cell’s own “quality control” system to correct the mutation. The comparison will be performed first using muscle cells isolated from a mouse model for DMD, and then in the mice themselves, to determine the feasibility of using this technology in people.

The repair process is simple to describe, but complicated in practice. The therapy needs to reach many different muscle fibers, cross the dense and protective structure that surrounds every fiber, reach the cell nuclei and ultimately the dystrophin gene, and then direct the gene correction process. Finally, the amount of dystrophin expression achieved after correction needs to be sufficient to sustain muscle function over a prolonged period of time.

“Every one of these steps is necessary to ensure a safe and effective therapy in patients,” says Bertoni. “Altogether these studies have the potential to significantly advance the field of gene correction into a clinical scenario for the treatment of DMD.”

Funding for this MDA grant began August 1, 2013.

Gregory Block, senior fellow in pediatrics at the University of Washington in Seattle, was awarded an MDA development grant totaling $179,994 over a period of three years to search for treatment targets infacioscapulohumeral muscular dystrophy (FSHD).

FSHD occurs when a section at the tip of one chromosome, chromosome number 4, is shortened. When that happens, it allows a gene called DUX4 to remain active into adulthood, instead of becoming inactive after early development. The symptoms of FSHD are due to this extended activity of DUX4, so preventing that activity, or blocking its effects, could be therapeutic in the disease. Block has developed a cell-based system to study DUX4 activation, and has found one chemical pathway in muscle cells that can prevent activation. He will continue investigating this pathway to determine if it can be used to develop treatments for FSHD.

“This is an exciting time for FSHD research,” Block says. “Four years ago, there was still considerable debate as to the genetic cause of the disease, and today we are challenged with defining pragmatic approaches for disease intervention. We are hoping the data generated from this project will provide considerable insight into the mechanisms used by cells to silence DUX4.”

Funding for this MDA grant began August 1, 2013.

Thomas Cooper, professor of pathology and immunology at Baylor College of Medicine in Houston, Texas, was awarded an MDA research grant totaling $300,000 over a period of three years to develop “antisense” therapy approaches to treat type 1 myotonic muscular dystrophy (MMD1, also known as DM1).

MMD1 is caused by an expanded section of a gene, which in turn causes excess accumulation of a normal cellular molecule called RNA. The extra RNA then traps other molecules that are important for processing the genetic instructions that are used to make proteins. Cooper has created a mouse model of MMD1 in which he has begun to explore the details of these effects, and in which he will now begin to test a therapeutic strategy for the disease. He is developing antisense oligonucleotides — short RNA-like molecules that bind to the excess RNA, blocking its interactions with other substances or causing it to be broken down. A particular challenge is delivering the antisense oligonucleotides to the heart muscle, which is affected in MMD1; Cooper will be exploring how best to accomplish this in the mouse.

“There has been rapid progress in the use of antisense molecules as a potential therapy for myotonic dystrophy,” Cooper says. "In animal models, there has been some success delivering the therapy to skeletal muscles. We will focus on delivery of the antisense oligonucleotides to the heart.”

Funding for this MDA grant began August 1, 2013.

Constanza Cortes, a postdoctoral researcher at the University of California, San Diego, was awarded an MDA development grant totaling $177,410 over a period of three years to study the role of a cell recycling system inspinal-bulbar muscular atrophy (SBMA or Kennedy disease) andamyotrophic lateral sclerosis (ALS).

Both SBMA and ALS are characterized by the death of motor neurons, the nerve cells that control movement. Their causes are different, but in both diseases, there are defects in autophagy, a process cells use to break down and recycle large proteins and other cellular substances. Autophagy is critical for cell health, but relatively little is known about the process in neurons, Cortes says. She will be using both light microscopy and electron microscopy to examine how the function of one regulator of the process — a protein called TFEB — may be altered by interaction with the mutant protein that causes SBMA.

Working with cell culture, mouse models and cells from patients, Cortes says, “We expect to develop autophagy-intervention therapeutics and test these approaches in our mice, to determine the feasibility of manipulating autophagy as a therapeutic strategy for neuromuscular diseases. In this project, I hope to demonstrate the importance of neuronal autophagy for neuromuscular disease, and advance the field in ways that will benefit patients suffering from these debilitating disorders.”

Funding for this MDA grant began August 1, 2013.

Rachelle Crosbie-Watson, professor of neurology at the University of California, Los Angeles, was awarded an MDA research grant totaling $300,000 over a period of three years to study whether increasing levels of the sarcospan protein can be therapeutic for Duchenne muscular dystrophy (DMD) and other muscle diseases.

In DMD, one of the major consequences of loss of dystrophin protein is that the muscle membrane, called the sarcolemma, becomes less stable and easier to damage. Replacing lost dystrophin is one therapeutic strategy; increasing sarcolemma stability through other means is an alternative.

“We have discovered a novel method that improves sarcolemma stability and adhesion [holding together],” Crosbie-Watson says, and the current study is aimed at testing the mechanisms and feasibility of this novel approach in animal models of DMD, limb-girdle muscular dystrophy (LGMD) and congenital muscular dystrophy (CMD).

The method involves delivering the gene that codes for the sarcospan protein. Raising the level of sarcospan leads to multiple effects at the sarcolemma, all contributing to increasing its stability. “We have shown that sarcospan ameliorates muscular dystrophy in the dystrophin-deficient mouse model for DMD, and we rationalize that sarcospan treatment will also benefit other forms of muscular dystrophy resulting from loss of muscle cell adhesion,” she says. The advantage of this approach is that, unlike dystrophin, the sarcospan gene is small and easily accommodated in the safest gene therapy vectors. Crosbie-Watson will continue fine-tuning this approach in the DMD mouse model, and extend it to models of LGMD and CMD.

“The outcome of these experiments will contribute to a better understanding of the molecular events contributing to the ability of sarcospan to alter expression of proteins at the cell surface,” she says, “and reveal the efficacy of sarcospan for the treatment of other muscular dystrophies.”

Funding for this MDA grant began August 1, 2013.

Robert Dirksen, professor of pharmacology and physiology at the University of Rochester Medical Center in Rochester, N.Y., was awarded an MDA research grant totaling $300,000 over a period of three years to evaluate calcium transport as a target for central core disease (CCD).

CCD is an inherited muscle disease that causes poor muscle tone and weakness, susceptibility to heat-related illnesses, and a risk of malignant hyperthermia, a dangerous reaction to certain anesthetic drugs. One cause of CCD is a defect in a muscle protein called the type 1 ryanodine receptor, which regulates the releases of stored calcium in the muscle. This release of calcium is critical for normal muscle contraction. Dirksen is working with a mouse model of CCD that carries a defect in the receptor. He will be exploring whether altering the receptor’s function with drugs or other means can ameliorate the disease in this model. In the process, he hopes to better define the pathways that lead to muscle damage in the disease.

“This project will define specific pathways that mediate core myopathy and muscle heat generation, and couple these fundamental advancements toward the testing and development of new drug interventions,” Dirksen says. “The benefits include an evaluation of the efficacy of targeted therapeutic interventions for the prevention of core myopathy and heat-induced sudden death in an established mouse model, and the likelihood that the results will lead to the first drug therapy for CCD and heat-related illness in humans.”

Funding for this MDA grant began August 1, 2013.

Marilena D’Aurelio, assistant research professor at Weill Medical College of Cornell University in New York City, was awarded an MDA research grant totaling $300,000 over a period of three years to test whether dietary supplementation can be therapeutic in mitochondrial myopathies.

Several muscle diseases are caused by genetic defects in cell structures called mitochondria. Mitochondria produce the energy used by muscle cells for all their functions, including contraction. In patients with some forms of mitochondrial myopathies, D’Aurelio has found specific impairments in the ability of cells to process the amino acid glutamine, which contributes to the energy deficit. She also has developed evidence that bypassing this process improves the survival of these cells. She will now study the glutamine impairment in a mouse model of mitochondrial myopathy, and explore the possibility that bypassing it with a dietary supplement can be therapeutic.

“In mitochondrial diseases, the energetic defects preferentially affect tissues with high-energy demand,” D’Aurelio says. “Brain, nerves, muscle and heart are often impaired in the same patient, presenting difficult and challenging conditions for diagnosis and therapy. Attempts to treat mitochondrial diseases have been disappointing thus far, due mostly to the lack of defined targets.”

Her work will test whether the impairment in glutamine processing may offer a viable therapeutic target.

Funding for this MDA grant began August 1, 2013.

Charles Gersbach, assistant professor at Duke University in Durham, N.C., was awarded an MDA research grant totaling $300,000 over a period of three years to develop a new approach for gene therapy in Duchenne muscular dystrophy (DMD).

The most common gene therapy approaches in DMD involve supplying new dystrophin genes (the dystrophin gene is mutated in the disease), allowing the new genes to integrate into existing chromosomes or to remain outside the chromosomes. The first approach can potentially disrupt other genes, while the second only provides temporary therapy that requires frequent re-administration, raising risks.

“An exciting alternative to these approaches is a new technology, called genome editing, that can target the addition of therapeutic genes to specific sites in the genome or directly repair the disease-causing mutations [in existing genes],” says Gersbach. The technique is already being tested in early-stage clinical trials in HIV and cancer.

Genome editing holds the potential for fixing mutated genes permanently. The approach may apply to all genes and all kinds of mutations, including large deletions. 

In this project, the overall objective is to engineer and test enzymes called nucleases to see if they can either deliver the dystrophin gene or repair existing mutant dystrophin gene sequences. The enzymes will be tested in cultured cells from DMD patients and in a mouse model of the disease.

“New technologies for gene delivery and gene modification are overcoming the challenges of translating gene therapy into correction of genetic diseases,” Gersbach says. “These technologies are expected to lead to dramatic advances in gene therapy in the next few years.”

Funding for this MDA grant began August 1, 2013.

Peter Hiesinger, associate professor at the University of Texas Southwestern Medical Center in Dallas, was awarded an MDA research grant totaling $300,000 over a period of three years to investigate the causes of type 2B Charcot-Marie-Tooth disease (CMT2B).

CMT2B is caused by mutations in a gene called rab7. The protein made from the gene performs a critical function in the degradation of debris in all cells. “Even though the gene is known, it is unclear how the mutations found in patients affect the gene’s function,” Hiesinger says. Without knowing how the mutation causes disease, it is difficult to design a therapy to treat it. He has developed models of the disease that suggest the mutation causes the protein to no longer be active, and that this loss of function affects nerve cells before other cells in the body.

“Our findings explain the genetic dominance [only one mutant copy of the gene, from either parent, is needed to develop the disease] and reveal a particular sensitivity of nerve cells for a defect in debris removal,” says Hiesinger. “This discovery opens the door for an understanding and a potential therapy of CMT2B based on the molecular manipulation of the underlying cause.

“Importantly,” he adds, “we suggest an increase of rab7 function as a therapeutic opportunity, in contrast to the currently suggested reduction of mutant gene function.”

In this project, Hiesinger will test this hypothesis of disease in a fly model of CMT2B and investigate rab7 function in detail.

Funding for this MDA grant began August 1, 2013.

Jyoti Jaiswal, associate professor at George Washington University School of Medicine and Health Sciences and investigator at Children’s Research Institute in Washington, D.C., was awarded an MDA research grant totaling $300,000 over a period of three years to evaluate whether a new anti-inflammatory compound can reduce muscle damage in dysferlinopathies.

Dysferlinopathies are muscle diseases due to mutations in the dysferlin gene, an important muscle repair protein. They include limb-girdle muscular dystrophy 2B and Miyoshi myopathy. Jaiswal is studying patient cells and mouse models to determine whether a new compound, called VBP15, can improve muscle damage.

“Unlike some of the other muscular dystrophies where anti-inflammatory steroidal drugs are beneficial, these drugs are ineffective in dysferlinopathy patients,” Jaiswal says. “At present, there are no drugs available for dysferlinopathy, and the drugs being tested do not simultaneously address the poor muscle cell membrane repair and muscle inflammation — two of the key deficits common to dysferlinopathy patients.”

VBP15 improves the ability of muscle cells to heal damage to their outer membrane and is a potent anti-inflammatory agent that lacks the metabolic side effects associated with use of steroidal anti-inflammatory drugs. It is currently approaching clinical trials for other diseases.

“Establishing the preclinical benefits of VBP15 using dysferlinopathic mice could make this a viable drug-based therapy for dysferlinopathy patients,” Jaiswal says.

Funding for this MDA grant began August 1, 2013.

Nicholas Johnson, assistant professor of neurology at the University of Utah in Salt Lake City, was awarded an MDA research grant totaling $375,000 over a period of three years to develop natural history data oncongenital-onset type 1 myotonic muscular dystrophy (MMD1, also known as DM1).

Congenital MMD1 is a severe form of myotonic dystrophy that begins in infancy. Because it is a rare condition, there is not as much known about the usual course of the disease as there is for adult-onset forms of myotonic dystrophy. Johnson will be conducting a “natural history” study to collect information on the most critical symptoms and how those symptoms change over time. Specifically, he will assess quality of life, cognition, speech, muscle strength and gastrointestinal symptoms in children with congenital MMD1 every year over a three-year period.

“This will allow for appropriate symptoms to be targeted in future treatment trials, as well as determining the age of children who will benefit the most from future treatments,” Johnson says.

“Recent data from preclinical models suggest antisense oligonucleotide therapy [a strategy for removing the harmful accumulation of RNA that causes the disease] may prove to be a very effective therapeutic approach for type 1 myotonic dystrophy, and human clinical trials are anticipated shortly. If antisense oligonucleotide therapy appears safe, there will be great urgency to extend clinical trials to children with myotonic dystrophy, particularly those most severely impacted by the disease,” he says. Therefore, collecting natural history data now will allow future trials to proceed more quickly.

Funding for this MDA grant began August 1, 2013.

Kleopas Kleopa, professor at the Cyprus Institute of Neurology and Genetics in Nicosia, Cyprus, was awarded an MDA research grant totaling $280,945 over a period of three years to develop gene therapy in a mouse model of X-linked Charcot-Marie-Tooth disease (CMT).

CMTX is due to mutations in the gene for connexin 32. This protein forms connections between layers of the insulating material around nerve cells, called myelin. Loss of connexin prevents the nerve cell from functioning properly, leading to muscle atrophy, weakness and sensory loss in the limbs. Kleopa has generated a mouse model of the disease, and has developed virus-like particles that can carry a functional copy of the gene, increasing connexin 32 protein production when delivered directly to the nerve.

Now, Kleopa will study a combination of gene delivery methods, including direct injection into the nerves, muscles and spinal cord. He also will examine treated mice for signs that the gene improves neuropathy (nerve abnormalities).

“Transgenic mice are particularly well suited for this study because treatment of peripheral neuropathy can only be validated in a vertebrate animal model, where the pathology can be studied in peripheral nerves,” Kleopa says. “Furthermore, this particular mouse model reproduces all major pathological aspects of the human disease, and therefore it is relevant to test potential treatments.

“In the last two decades research in the field of inherited neuropathies, especially the common forms, has provided many insights into the causes and mechanisms of disease. Developing genetic treatments, using the recently generated disease models, is an important and timely approach to also provide potential therapies for these disorders in the near future.”

Funding for this MDA grant began August 1, 2013.

Albert La Spada, professor of cellular and molecular medicine, neurosciences and pediatrics at the University of California, San Diego, was awarded an MDA research grant totaling $300,000 over a period of three years to study the causes of neurodegeneration (loss of nerve cells) inspinal-bulbar muscular atrophy (SBMA).

SBMA, also known as Kennedy disease, is an adult-onset neuromuscular disorder affecting men. It is caused by a mutation in the gene for theandrogen receptor protein, and it leads to the death of motor neurons, which are needed to control muscle contraction.

La Spada has created a mouse model and neuronal cell culture models of SBMA. He will now use these models to investigate how the SBMA-causing mutation leads to the death of motor neurons, focusing on changes in metabolism and impaired degradation of worn-out or defective proteins.

La Spada’s lab will test drugs that target a proposed regulatory factor and also will see whether blocking the erroneous androgen receptor gene instructions with compounds known as antisense oligonucleotides is beneficial. In previous work funded by MDA, La Spada’s lab has shown that directing therapies to muscle cells, rather than directly to the nerve cells that die in SBMA, can prevent the disease in mice.

“This exciting and unexpected finding represents an important step toward successful therapy development, as treatments that target muscle [instead of nerve cells] should be more straightforward to create, easier to test in patients and less likely to cause serious side effects,” La Spada says. “This key finding also suggests that a similar strategy is worth considering for related motor neuron diseases, such as spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS).”

Funding for this MDA grant began August 1, 2013.

Lynn Megeney, senior scientist at the Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute in Ottawa, Ontario, Canada, was awarded an MDA research grant totaling $300,000 over a period of three years to study how muscle stem cells are controlled.

When muscles are damaged, stem cells called satellite cells divide to form new muscle. In muscular dystrophies such as Duchenne (DMD) andBecker (BMD) muscular dystrophies, satellite cells offer a pool of stem cells that, at least temporarily, can replace the muscle cells that are lost in the disease. However, Megeney notes, “the steps that control the self-renewal process of these cell types remain largely unknown.” He is investigating the role of a critical enzyme called caspase 3, which promotes maturation of satellite cells into muscle fibers. Caspase 3 targets and cleaves other proteins, either activating or destroying them, and thus altering cell development. Megeney has identified one such target, calledPax7, and will work to learn more about this system and to discover other caspase 3 targets, in both cell culture and mouse models of muscular dystrophy.

“We anticipate that the knowledge gained through our research efforts will provide a means to direct both the self-renewal process, as well as the maturation steps toward fully functional adult muscle cells,” Megeny says. “These basic science innovations will influence stem cell mediated therapies in general, impacting the range of dystrophies that are amenable to such a therapeutic intervention.”

Funding for this MDA grant began August 1, 2013.

Douglas Millay, a postdoctoral researcher at the University of Texas Southwestern Medical Center in Dallas, was awarded an MDA development grant totaling $180,000 over a period of three years to study the process ofmyoblast fusion.

Mature muscle fibers form from the fusion of individual cells, calledmyoblasts. Myoblast fusion occurs both during development and during repair of muscle in later life. Because it is such a central process in muscle repair, understanding myoblast fusion is important for understanding how muscles in muscular dystrophies first repair themselves, and then ultimately exhaust their self-repair ability.

Millay is studying a gene called myomaker, which is an essential component for myoblast fusion, helping to control the timing and location of the fusion process. “Using mouse models and primary muscle cells, we will study the function of this protein in muscular dystrophy disease progression,” he says. “These studies will reveal general mechanisms of mammalian myoblast fusion, expanding our knowledge of this process and identifying avenues for future therapeutic intervention.”

That intervention might take the form of cell-based therapies, in which myoblasts are transplanted into diseased muscle. While this approach has been tried unsuccessfully in the past, a better understanding of the molecules directly mediating myoblast fusion may increase the chances of success, Millay says.

Funding for this MDA grant began August 1, 2013.

Umrao Monani, associate professor at Columbia University Medical Center in New York City, was awarded an MDA research grant totaling $300,000 over a period of three years to study how junctions between neurons and muscle are affected in spinal muscular atrophy (SMA).

SMA is due to a gene mutation that causes a deficiency in a protein calledSMN. Without it, the nerve cells that control muscles, called motor neurons, die off and muscles weaken. One of the first effects of lack of SMN is seen at the neuromuscular synapse, the place on the surface of the muscle where the motor neuron contacts it and sends its signal to control muscle contraction.

“We are interested in investigating the role of SMN in the formation, function, maintenance and repair of these structures,” says Monani. “We will use model mice, in which defects of the neuromuscular synapses become apparent when the SMN protein is depleted, to determine how SMN might shape synaptic structure and function.

"By examining molecular changes that occur normally in the motor neurons and muscle as the synapses mature, and by looking for differences when SMN is reduced, we hope to identify specific mediators of the SMA disease process. Understanding how low SMN levels translate into a disease that affects the motor system is not only of enormous scientific interest but is also likely to teach us how best to effectively treat SMA and other diseases of the motor neurons,” he says.

Funding for this MDA grant began August 1, 2013.

Moon-Chang Choi, a postdoctoral researcher at Duke University in Durham, N.C., was awarded an MDA development grant totaling $120,000 over a period of two years to study one of the molecular controls regulating muscle repair.

When muscle becomes damaged, new muscle cells form by division ofsatellite cells, a type of stem cell found in muscles. “Understanding the mechanism that controls satellite cell activation could provide opportunities to increase muscle regeneration and provide therapeutic relief to patients with Duchenne muscular dystrophy (DMD),”Choi says.

His work will focus on a protein called HDAC4, which he has previously shown is required for satellite cell activation in damaged muscle. Now, Choi will further characterize the role of HDAC4 in satellite cell activation, using a mouse model in which HDAC4 is specifically inactivated in satellite cells. He also will examine the effect of a loss of HDAC4 in the most commonly used mouse model of DMD.

“The ability of muscle stem cells to transition from a quiescent state to a rapidly proliferative state is one of the most remarkable but mysterious aspects of stem cell biology,” Choi says. “Given that the satellite cell program is often impaired in muscle dystrophy, the study of these fundamental mechanisms could have important clinical implications.”

Funding for this MDA grant began August 1, 2013.

Bennett Novitch, assistant professor of neurobiology at the University of California, Los Angeles, was awarded an MDA research grant totaling $300,000 over a period of three years to study the development of motor neurons that control respiration and their significance for spinal muscular atrophy (SMA).

SMA is due to the loss of motor neurons (nerve cells that control muscle activity), and in the most severe forms of SMA, the motor neurons controlling respiration are affected early in the disease.

“These observations raise the possibility that these respiratory defects might have a developmental origin [that is, they may arise in the developing embryo or fetus],” Novitch says, “resulting either from the improper formation of respiratory motor neurons, or their integration into functional motor circuits. This issue has been difficult to address, however, as our knowledge of the developmental origins of respiratory motor neurons and their assembly into circuits is incomplete.”

In this study, Novitch will study development of respiratory motor neurons and their organization into motor circuits that carry out both inspiration and expiration (breathing in and out). He also will study the gene networks that control this development. Better understanding of these networks, and the developmental processes they control, may lead to better understanding of how respiratory motor neurons are affected in SMA.

“Our study will provide new insights into the root causes of SMA and potentially lead to the discovery of new therapeutic targets. Moreover, by studying the process by which respiratory motor circuits are initially formed, we will gain vital information on how this activity may be recapitulated to rebuild damaged circuits to help patients maintain their ability to breathe independently,” he says.

Funding for this MDA grant began August 1, 2013.

Michael Pape, president of Nymirum in Ann Arbor, Mich., was awarded an MDA research grant totaling $197,066 over a period of one year to develop drugs to treat type 1 myotonic muscular dystrophy (MMD1, also known as DM1).

MMD1 is due to a gene expansion, which causes a molecule called RNA to accumulate and aggregate (clump together). These RNA aggregates trap a protein called muscleblind, which normally regulates the formation of many other proteins. Loss of muscleblind accounts for many of the features of MMD. One strategy to treat the disease is to prevent the interaction of muscleblind and the RNA aggregates, by blocking the portion of the RNA (called a CUG repeat) where the two bind together.

“Several studies using small molecules and oligonucleotides show that CUG-binding molecules can inhibit muscleblind binding and alleviate the mutation-mediated dysfunctions,” Pape says. “While these studies provide proof of concept, none of the small molecules possesses the required efficacy [effectiveness] and/or drug-like properties for chronic treatment.”

Nymirum has discovered two sets of molecules that appear to have the potential to overcome these limitations. Nymirum will now pursue modifications to these molecules to increase their affinity for the expanded RNA and enhance their therapeutic potential.

Funding for this MDA grant began August 1, 2013.

Terence Partridge, professor of integrative systemic biology and pediatrics at George Washington University and associate director of the Children’s Research Institute in Washington, D.C., was awarded an MDA research grant totaling $300,000 over a period of three years to investigate differences in muscle repair mechanisms in mice and humans, in the context of Duchenne muscular dystrophy (DMD).

When muscle is damaged, cells called satellite cells divide in order to replace the damaged muscle. This occurs in DMD, but eventually the satellite cell repair system is exhausted, leading to irreversible loss of muscle tissue. Mice also employ satellite cells, but the mouse system differs in some important ways from the human one, and these differences may have an impact on lessons that can be learned from using a mouse model of DMD (called the mdx mouse) to study repair in DMD.

Partridge will use the mdx mouse to investigate differences between satellite cell muscle building early and later in the mouse life cycle. “We now have ways of indelibly marking satellite cells during growth," Partridge says. "We can use this to ask whether the cells that are repairing the dystrophic muscle after two years of continuous repair are descended from the cells that were used for growth during the first three weeks of life, or whether they are recruited from other stem cell sources.

“At present, we do not know whether interventions designed to augment muscle regeneration that have been devised in the mdx mouse would be applicable to humans,” he says. “Design of effective strategies for rescuing or enhancing muscle repair in DMD requires that we learn which cells to use and how best to use them. We aim therefore to identify the significant participants and to characterize their relative roles in the formation, maintenance and repair of normal and chronically diseased muscle.”

Funding for this MDA grant began August 1, 2013.

Grace Pavlath, professor of pharmacology at Emory University in Atlanta, Ga., was awarded an MDA research grant totaling $100,000 over a period of one year to characterize a more accurate mouse model ofoculopharyngeal muscular dystrophy (OPMD).

OPMD is an adult-onset disease characterized by eyelid drooping and difficulties in swallowing, as well as weakness in the thighs and upper arms. The mutation responsible for the disease is found within a gene calledPABPN1, which regulates expression (activity) of other genes. In the most common form of the disease, called autosomal dominant OPMD, those who are affected carry one mutated copy of the gene and one normal copy.

However, Pavlath says, current mouse models of OPMD contain two normal alleles of PABPN1 in addition to one mutant allele of PABPN1, meaning there is a higher level of normal PABN1 protein made in these mice than in humans with the disease. “Thus, these mouse models do not accurately reflect the genotype of OPMD patients,” she says.

Now, Pavlath has created a mouse model that is closer to the human situation, permitting her to conduct experiments to better characterize the effects of the mutation in this model.

“These mice will be the first opportunity to accurately model this disease in mice and could provide a tool both for understanding how the disease affects muscle and for finding therapies to treat the disease,” she says.

Funding for this MDA grant began August 1, 2013.

Morayma Reyes, assistant professor of pathology at the University of Washington in Seattle, was awarded an MDA research grant totaling $300,000 over a period of three years to study a strategy for reducing heart muscle damage in Duchenne muscular dystrophy (DMD).

People with DMD develop cardiovascular problems in their early teen years, and cardiac complications are the major cause of death in the disease. A significant contributor to the damage done to heart muscle is fibrosis, or development of fibrous tissue within the muscle. Fibrosis is a response toinflammation, part of the body’s immune response. Reyes will be studying the effect of blocking a molecular pathway that contributes to that inflammation.

She has characterized cells surrounding blood vessels within the fibrotic tissue of heart muscle in the mdx mouse, a mouse model of DMD. “We hypothesize that these cells respond to inflammatory cues and deposit collagen, and thus form fibrotic tissue in the perivascular tissue of mdx hearts,” she says. “We will study the role of these cells in mdx cardiac fibrosis.”

In particular, she will study a potentially important signaling pathway, called the PDGF receptor alpha pathway. “We hypothesize that signaling through PDGF receptor alpha results in activation of a fibrotic program in these cells. We will test this by administration of PDGF-A, which should result in increased fibrosis.”

She will then block the pathway to reduce fibrosis, testing the potential benefits of a drug called Crenolanib. “These studies will lay the foundation for preclinical studies using Crenolanib to treat fibrosis in DMD patients,” Reyes says.

Funding for this MDA grant began August 1, 2013.

James Shorter, associate professor of biochemistry and biophysics at the University of Pennsylvania in Philadelphia, was awarded an MDA research grant totaling $300,000 over a period of three years to develop an experimental approach targeted at protein aggregates in amyotrophic lateral sclerosis (ALS).

In almost all cases of ALS, aggregates or “clumps” of protein accumulate in motor neurons, which may contribute to the death of these cells. Shorter is exploring the possibility that disaggregating [breaking apart] these proteins and returning them to their normal state may be therapeutic. “Unfortunately, mammalian cells have limited ability to disaggregate and renature [properly refold] proteins,” Shorter says, so he employs an enzyme from yeast, called Hsp104.

Shorter is planning to generate variants of the Hsp104 protein that are even more active at breaking up aggregates of the various proteins known to be involved in ALS, including TDP43, FUS and SOD1. After generating such variants, he will test their abilities in yeast and fruit flies, another standard lab model.

“Hsp104-based disaggregases [enzymes that break up aggregates] likely hold great potential as ALS therapeutics,” he says, “as well as for unraveling the role of protein aggregation in ALS pathogenesis.”

Funding for this MDA grant began August 1, 2013.

Hansell Stedman, associate professor of surgery at the University of Pennsylvania in Philadelphia, was awarded an MDA research grant totaling $300,000 over a period of three years to study early immune responses during administration of gene therapy.

Gene therapy is a promising treatment strategy for Duchenne muscular dystrophy (DMD) and other muscle diseases, but it has been hindered by the body’s immune response. Genes can be delivered via virus-like particles (viral vectors), but the immune system can identify them as foreign, and mount a response that can inactivate the vector and cause inflammation in the muscle. Stedman plans to study the very earliest phases of the immune response, combining approaches gleaned from immunology, surgical critical care, genetics and virology.

“This mechanistic information will identify rational targets for transient immunosuppression prior to vector administration,” Stedman says, “thereby improving the chances for safe and durable therapy for these devastating childhood-onset diseases.” His work will be performed in the mouse model of DMD.

“In our view, the entire field is tantalizingly close to the development of gene therapy for Duchenne and other forms of muscular dystrophy, but we must explore a number of strategies to address the remaining obstacles,” he says. “Understanding how the innate immune system recognizes injured cells should improve our chances for a successful intervention.”

Funding for this MDA grant began August 1, 2013.

Charlotte Sumner, associate professor of neurology and neuroscience at Johns Hopkins University School of Medicine in Baltimore, Md., was awarded an MDA research grant totaling $300,000 over a period of three years to study the effects of the gene that causes one form of Charcot-Marie-Tooth disease (CMT).

CMT is characterized by the degeneration of peripheral nerves, resulting in disabling muscle weakness and sensory loss. One form of the disease, called type 2C CMT (CMT2C), is caused by mutations in a gene calledTRPV4 that helps control the flow of calcium in and out of cells. “Our long-term goal is to determine how mutations in TRPV4 lead to CMT2C and to develop treatments for this disease,” Sumner says.

Some effects of these gene mutations are known, but how they cause nerve degeneration is still unclear. Sumner has generated fly and mouse models of CMT2C in order to pursue that question. “The advantage of using fruit flies is that they allow us to rapidly evaluate the effects of multiple mutations and potential disease modifiers, as well as to assess TRPV4 function by calcium imaging.” The mouse, in turn, better mimics aspects of human physiology affected in the disease and can be used to test drugs.

“Together, these studies will provide important insights into the cellular and molecular mechanisms underlying TRPV4-mediated nerve disease, and in the future, we plan to use these fly and mouse models synergistically to develop new therapeutic interventions,” she says. “Because it is an ion channel expressed at the cell surface membrane [and therefore potentially accessible by therapeutic compounds], TRPV4 inhibition represents an attractive therapeutic strategy for patients with CMT2C.”

Funding for this MDA grant began August 1, 2013.

Maurice Swanson, professor of molecular genetics and microbiology at the University of Florida College of Medicine in Gainesville, was awarded an MDA research grant totaling $300,000 over a period of three years to develop models to study sleep disturbance in types 1 and 2 myotonic muscular dystrophy (MMD1 and MMD2, also known as DM1 and DM2).

MMD1 and MMD2 are caused by a gene expansion that leads to loss of a protein called muscleblind. Muscleblind regulates the formation of many different proteins, only some of which affect muscle. People with MMD and their families have noted that one of the most debilitating aspects of this disease is hypersomnia or excessive daytime sleepiness, and animal models of the disease also display sleep disturbance. This suggests that loss of muscleblind in MMD likely affects the central nervous system's regulation of sleep.

Therefore, the goal of Swanson’s study is to define the molecular mechanisms underlying abnormal sleep regulation in MMD. He will develop mouse and cell models to study how normal circadian rhythms are altered by inhibition of muscleblind and related proteins, and identify the keycircadian cycle regulatory genes that are affected in MMD.

“This study should provide significant new insights into the cellular basis for abnormal sleep patterns” in MMD, he says, “and promotes the development of novel therapeutics to treat excessive daytime sleepiness.”

Funding for this MDA grant began August 1, 2013.

Lee Sweeney, director of the Penn Center for Orphan Disease Research and Therapy at the University of Pennsylvania Perelman School of Medicine in Philadelphia, was awarded an MDA research grant totaling $278,286 over a period of three years to test whether a new treatment that affects muscle calcium can slow the damage to muscle tissue in several forms of muscular dystrophy.

A common characteristic of several types of muscular dystrophy is loss of regulation of calcium within muscle tissue. Calcium plays an important role in muscle contraction, and the inability to keep its level well-regulated reduces the force the muscle can generate, and contributes to muscle degeneration. Sweeney has worked on the development and testing of a peptide (a short chain of amino acids) called CT38, which helps correct the calcium handling defect in muscle. The peptide has been shown to be safe in humans, and will now be tested in models of Duchenne muscular dystrophy, Miyoshi myopathy and myotonic muscular dystrophy.

“We will give this peptide to these mouse models of human muscular dystrophies and observe whether the muscles from these mice can generate more force over time, and if the peptide prevents eventual destruction of the skeletal muscles,” Sweeney says.

“For all of the muscular dystrophies, it is clear that there is the possibility of developing multiple drugs to go after different aspects of each disease. By developing these multidrug therapies, we hope we can move toward stopping disease progression. We feel that CT38 has the potential to be one of the drugs in our arsenal that will combat the muscular dystrophies.”

Funding for this MDA grant began August 1, 2013.

Julio Vergara, professor of physiology at the University of California, Los Angeles, was awarded an MDA research grant totaling $300,000 over a period of three years to study the basis of central core disease (CCD).

CCD is an inherited muscle disease that causes poor muscle tone and weakness, susceptibility to heat-related illnesses, and a risk of malignant hyperthermia, a dangerous reaction to certain anesthetic drugs. One cause of CCD is a defect in a muscle protein called the type 1 ryanodine receptor, which regulates the releases of stored calcium in the muscle. This release of calcium is critical for normal muscle contraction.

Much remains to be understood about the connections between CCD and alterations in the ryanodine receptor, Vergara says. His work will pursue these connections in mice carrying the mutant gene.

“Our research aims to answer the following questions,” Vergara explains. “Why do mutated receptors predispose muscle fibers to triggering agents that lead to fulminant [sudden, rapid, severe] malignant hyperthermia episodes? And, how does dantrolene, a commonly used drug, prevent fulminant MH episodes?”

He will investigate these issues using a combination of state-of-the art optical and electrophysiological approaches in adult muscle fibers from animal models, and comparing calcium release among mice with different mutations in the receptor gene.

“The mice have become a great tool to investigate the molecular and pathophysiological alterations underlying the mysteriously intertwined malignant hyperthermia/CCD human pathology,” Vergara says.

Funding for this MDA grant began August 1, 2013.

Zejing Wang, associate in clinical research at the Fred Hutchinson Cancer Research Center in Seattle, was awarded an MDA research grant totaling $300,000 over a period of three years to develop gene therapy forDuchenne muscular dystrophy (DMD) — with a focus on treating the heart — in a canine (dog) model of the disease.

DMD is caused by a mutation in the dystrophin gene. Gene therapy in DMD has focused on delivering the gene via a viral vector, or carrier, derived from adeno-associated virus (AAV).

“Despite encouraging results using AAV-mediated delivery of dystrophin into skeletal muscles,” says Wang, “few attempts have been made to genetically treat cardiomyopathy.” Cardiomyopathy, or disease of the heart muscle, remains a major cause of death in DMD, with few treatments available.

Mutations in dystrophin also occur naturally in some dog breeds, making them an important model for studying treatment of the disease.

“Our project will develop AAV-mediated gene therapy for treating cardiomyopathy in a preclinical DMD dog model that can then be applied to treat human DMD patients suffering from cardiac failure. The preclinical DMD dog model represents the most relevant animal model that faithfully mimics human DMD, reproducing many of its features not seen in the mouse model, including cardiomyopathy.”

Wang’s work will focus on improving the ability of the AAV vector to enter heart muscle cells and carry on long-term dystrophin production there.

“Developing strategies for efficient gene delivery and sustained transgene expression in heart muscle will increase the likelihood of achieving the goal of effective gene therapy and the ultimate reduction of mortality in DMD patients,” he says.

Funding for this MDA grant began August 1, 2013.

Steve Wilton, foundation chair in molecular therapies at the Centre for Comparative Genomics at Murdoch (Australia) University, was awarded an MDA research grant totaling $300,000 over a period of three years to develop exon-skipping compounds for the less common mutations causingDuchenne muscular dystrophy (DMD).

Exon skipping has emerged as a promising therapeutic strategy for DMD. An exon is a section of a gene; multiple exons are combined to make the instructions for a protein. In DMD, a mutation that affects one or more exons of the dystrophin gene can prevent the protein from being made properly.

By blocking an exon or exons near the mutation, it is sometimes possible to restore the cell’s ability to create a smaller-than-normal, but still functional, dystrophin protein.

Different people carry different mutations and will require that different exons be blocked to treat those mutations. Experimental treatments that block (“skip”) exon 51 are now being tested in clinical trials, and results from early trials indicate these treatments may be beneficial.

But these treatments can only treat those who can benefit from blocking exon 51, Wilton points out, accounting for about 15 percent of all cases of DMD.

“Individuals with different mutations in their dystrophin gene need to have other morpholino oligos [the name for the exon-skipping treatment] designed to address their dystrophin mutations. Our project will extend exon skipping to the rare exons and other mutations that require multiple exons to be removed.”

The goal, he says, is to have these treatments ready to test if the current exon 51-targeting therapies continue to show promise in the clinic.

“If this therapy is shown to be able to slow or halt the progression of DMD, we want to have lead morpholino candidates ready to treat as many other DMD mutations as possible.”

Funding for this MDA grant began August 1, 2013.