“Better understanding of the cellular and mitochondrial processes leading to COX assembly is expected to have a significant impact on health and neuromuscular disease. Our project will test therapeutic interventions involving copper delivery to mitochondria, which could be extremely useful to patients.”

Antonio Barrientos, PhD, professor of Neurology and Biochemistry and Molecular Biology at the University of Miami Miller School of Medicine, was awarded an MDA research grant totaling $300,000 over three years to study the relationship between genetic mutations and copper delivery to mitochondrial cells in the pathology of mitochondrial myopathies.

Mitochondria produce much of the energy that cells require to function, and an important component of that process is an enzyme called cytochrome c oxidase (COX). Without a properly assembled COX complex, cellular energy production is severely compromised; this affects the brain, muscles, and other organs with high energy demands. Previously, MDA awarded Dr. Barrientos funding to study the underlying molecular mechanisms of COX deficiency in some forms of mitochondrial myopathy as well as defects in mitochondrial protein complex assembly, which are a frequent cause of inherited mitochondrial myopathies.

The mitochondrial protein COX1, which is one of the proteins that make up the COX protein complex, requires copper in order to function and produce cellular energy. In this proposal, Dr. Barrientos will use patient-derived cells to study the proteins that help deliver copper to mitochondria, how their function is disrupted by mutations causing mitochondrial myopathies, and why this dysfunction is specific to certain tissues. Additionally, he will test various therapeutic strategies to enhance copper delivery.

“In this proposal we aim to identify the genes that modify the severity of SMA and the changes in them that cause modification of severity. The identification of these changes will improve the ability to predict severity with a DNA test and initiate treatment at the appropriate time. In addition, these modifier genes can be novel therapeutic targets that can act independently of current therapies to increase SMN.”

Arthur Burghes, PhD, professor of Biological Chemistry and Pharmacology, Molecular Genetics, and Neurology at The Ohio State University Wexner Medical Center in Columbus, was awarded an MDA research grant totaling $200,000 over two years to study genes that might have the potential to modify the severity of spinal muscular atrophy (SMA).

In SMA, mutations in the survival motor neuron 1 gene (SMN1) prevent a person from making enough survival motor neuron protein (SMN). Lack of this protein is what causes the loss of motor neurons, muscle weakness, and paralysis that define SMA. In addition to the SMN1 gene, there is also a related SMN2 gene, which functions as a “backup” to producing some amount of SMN protein.

Dr. Burghes was previously awarded MDA funding to study how SMN2 copy number might predict severity of SMA. Currently SMN2 copy number is the best predictor of SMA severity and in general, having more SMN2 copies results in less severe SMA. However, both SMA type 2 and type 3 patients have three copies of SMN2. In this new work, Dr. Burghes will study the DNA of siblings who have three copies of SMN2, but one has SMA type 2 while the other has SMA type 3. He aims to identify new genes with the potential to modify the severity of the symptoms of SMA, which may potentially become novel therapeutic targets.

“We hope this laminin-enhancing small molecule will slow muscle pathology and improve muscle strength in a mouse model of laminin-alpha2-related congenital muscular dystrophy. Successful preclinical outcomes from this study will form the basis for potential future clinical trials for patients with this disease.”

Dean Burkin, PhD, professor of Pharmacology at the University of Nevada School of Medicine in Reno, was awarded an MDA research grant totaling $300,000 over three years to study a laminin-enhancing small molecule for treating congenital muscular dystrophy (CMD).

Laminin-alpha2-related congenital muscular dystrophy, also known as merosin-deficient congenital muscular dystrophy (MDC1A), is a muscle disease with no cure or treatment. Children with MDC1A typically die at a young age. MDC1A is caused by mutations in the laminin-alpha2 gene, which lead to a lack of merosin or laminin-211/221 in muscle. Laminin-511 (aka, laminin-alpha5) is another form of laminin found in the muscle of MDC1A patients and is similar in structure and function to laminin-211.

Dr. Burkin has recently identified an FDA-approved small molecule, designated laminin-enhancing small molecule 5 (LEM5), that increases laminin-alpha5 in cultured skeletal muscle cells and improves muscle pathology and function in a mouse model of MDC1A. With this new funding, Dr. Burkin will use a LEM5 analog (a modified version of the FDA-approved drug) to determine optimal dose, safety, and efficacy in reducing symptoms in MDC1A mice.

“We hope that we can demonstrate good bioavailability of the antisense oligonucleotide (ASO) therapy in muscle cells and high in vivo efficacy in the mouse model, which will allow us to move this forward for drug development.”

Yi-Wen Chen, DVM, PhD, associate professor at the Center for Genetic Medicine Research, Children’s Research Institute (CNMC) in Washington, DC, was awarded an MDA research grant totaling $200,000 over two years to develop an antisense oligonucleotide (ASO) therapy for facioscapulohumeral muscular dystrophy (FSHD).

FSHD leads to progressive degeneration of muscles, with the most pronounced effects appearing in muscles of the face, shoulder blades, and upper arms. FSHD is caused by abnormal expression of double homeobox 4 protein (DUX4), which causes toxicity and muscle cell death. Suppressing DUX4 expression is a primary therapeutic approach for halting disease progression, as it is thought that would prevent or slow down the many detrimental activities of this toxic protein on muscle cells.

As a new MDA grant awardee, Dr. Chen will develop an ASO-based therapy to knock down DUX4 expression using the same backbone chemistry as was successfully used for Spinraza (the first disease-modifying therapy to treat spinal muscular atrophy, approved by the US Food and Drug Administration in December 2016). Dr. Chen will start with previously identified FSHD ASO candidates that showed efficacy in cell culture and see how well they work in FSHD mice, aiming to take these ASOs closer to pre-clinical and clinical trials for treating FSHD.

Martin Childers, PhD, DO, chief medical officer at Asklepios BioPharmaceutical Inc. in North Carolina, was awarded an MDA research grant totaling $192,500 over one year to perform pre-clinical studies using an adeno-associated virus (AAV) to deliver a gene therapy for limb-girdle muscular dystrophy type 2I (LGMD2I).

Limb-girdle muscular dystrophies are a diverse group of disorders with many subtypes categorized by disease gene and inheritance. LGMD2I is caused by mutations in the gene encoding fukutin-related protein (FKRP). In gene-replacement therapy for LGMD2I, an AAV vector is used to deliver a normal copy of the missing or mutated FKRP gene to a patient’s cells in order to make up for the inherited, non-functioning copy.

With this funding, Dr. Childers and Asklepios will build upon existing proof-of-concept work to collect the remaining pre-clinical data necessary for a first-in-human gene transfer clinical trial using AAV-FKRP in patients with LGMD2I. Upon successful completion of these studies, Asklepios will submit an Investigational New Drug (IND) application to the FDA, aiming to start a clinical trial in late 2020.

Peter Currie, PhD, professor of Medicine, Nursing, Health Sciences, and Developmental and Regenerative Biology at Monash University in Melbourne, Australia, was awarded an MDA research grant totaling $295,614 over three years to evaluate how correcting muscle stem cell dynamics in Duchenne muscular dystrophy (DMD) may help improve symptoms of the disease.

DMD is caused by a mutation in the dystrophin gene on the X chromosome that results in little or no production of dystrophin, a protein that is essential for keeping muscle cells intact. Recent studies, including those of Dr. Currie’s, have shown that dystrophin-deficient muscle has reduced ability to regenerate due to impaired function of satellite cells (a type of stem cell). Previous MDA-funded work allowed Dr. Currie to create zebrafish models of muscular dystrophy and screen for small molecules that can inhibit the onset of muscular dystrophy in these zebrafish.

Using this grant award, Dr. Currie will use his zebrafish system to examine the cellular and molecular processes that regulate muscle stem cell functions in vivo, which will hopefully enable new therapeutic approaches for the treatment of DMD. Dr. Currie will determine whether another membrane protein, laminin, can compensate for loss of dystrophin and restore satellite cell function and regeneration in DMD zebrafish.

“This work will provide critical insight for elucidating the mechanisms regulating protein aggregation and cell-to-cell spreading of protein aggregates, as well as [for] establishing safety and applicability of an antisense oligonucleotide (ASO) strategy as a therapy for fused in sarcoma (FUS) proteinopathies.”

Sandrine Da Cruz, PhD, assistant investigator of Neurobiology at the San Diego Branch of the Ludwig Institute for Cancer Research, was awarded an MDA research grant totaling $300,000 over three years to investigate the mechanisms underlying amyotrophic lateral sclerosis (ALS) caused by mutations in the fused in sarcoma (FUS) protein and potential therapies to treat the disease.

Despite having identified ALS-associated proteins, including FUS and TDP-43, the disease mechanism behind these proteins in ALS has yet to be discovered. Previously, Dr. Da Cruz used a mouse model to determine that if mutant FUS is delivered to the cytoplasm of a cell, then FUS aggregates there and spreads to adjacent cells in the central nervous system (CNS), worsening behavior in the mice associated with mutant FUS expression.

Dr. Da Cruz will use this funding to study both familial and sporadic ALS (and frontotemporal dementia, a related disease) in both an FUS mouse model and in cell culture. She will aim to determine the role of FUS aggregation and its cell-to-cell transmission in the CNS in the pathology of ALS. Dr. Da Cruz hopes to test the feasibility of lowering FUS levels using an antisense oligonucleotide as a first step in the development of a therapy, which may act to delay onset and slow progression of ALS.

“There is currently no disease-modifying treatment for CMT2A; mitofusin agonists may be the first. This is an orphan disease with a clear unmet need.”

Gerald W. Dorn, II, MD, professor of Medicine and director of the Center for Pharmacogenomics at Washington University School of Medicine in St. Louis and president of Mitochondria in Motion, Inc., was awarded an MDA research grant totaling $267,942 over two years to study mitofusin agonists to treat Charcot-Marie-Tooth disease (CMT).

There are many subtypes of CMT, each caused by different genetic mutations. CMT type 2A (CMT2A) is caused by mutations in the mitofusin 2 gene (MFN2), which regulates mitochondrial fusion and motility. Affected mitochondria are fragmented, dysfunctional, and immobile, leading to the symptoms of CMT, which include muscle weakness, atrophy, and loss of sensation in the lower legs and feet and sometimes the hands, wrists, and forearms.

Dr. Dorn previously discovered a compound that can act like the missing mitofusin in CMT2A. This mitofusin agonist has been shown to improve CMT2A mitochondrial abnormalities in human and mouse tissue culture models. Dr. Dorn recently helped found a biotechnology company, Mitochondria in Motion, and he will use the new MDA funding to modify the company’s lead compound to make it more “drug-like” and then show that this improved drug can halt or reverse the progression of CMT2A in a humanized mouse model. It is hoped that this will move the field closer to first-in-human clinical trials for this new class of drugs.

“I expect to determine how stathmin-2 provides a crucial role in the maintenance and regeneration of the neuromuscular junctions that connect motor neurons and skeletal muscles. With this, I hope to uncover insights for the development of ALS treatments that will halt the progression of the disease from its early phases.”

Jone Lopez Erauskin, PhD, postdoctoral fellow in Cellular and Molecular Medicine at the San Diego Branch of the Ludwig Institute for Cancer Research, was awarded an MDA development grant totaling $210,000 over three years to study the mechanisms of maintenance and regeneration of the neuromuscular junction (NMJ) in amyotrophic lateral sclerosis (ALS).

Normally, nerve cells communicate with muscle cells by sending electrical signals across the NMJ. Frequently, disruption of this communication happens early in the course of ALS. Recently, Dr. Lopez Erauskin discovered that the loss of stathmin-2, a neuronal growth-associated protein, is universally found in sporadic and familial (inherited) ALS, and that stathmin-2 is essential for axonal (nerve fiber) regeneration.

In this project, Dr. Lopez Erauskin seeks to identify the mechanisms that underlie disruption of nerve-muscle connections in ALS through the loss of stathmin-2. These studies may enable the design of therapeutic strategies to maintain or restore nerve-muscle connections, thereby delaying or halting disease progression in ALS.

“While there has been tremendous progress in the advancement of therapies to treat DMD patients, we still have not cured anyone of the disease, and I believe that a better understanding of the problem will lead to better solutions.”

James Ervasti, PhD, professor of Biochemistry, Molecular Biology, and Biophysics at the University of Minnesota, Twin Cities, in Minneapolis, was awarded an MDA research grant totaling $300,000 over three years to study the mechanical characterization of dystrophin in Duchenne muscular dystrophy (DMD).

DMD is caused by a mutation in the dystrophin gene on the X chromosome that results in little or no production of dystrophin, a protein that is essential for keeping muscle cells intact. Dystrophin, and the related protein utrophin, have long been hypothesized to protect muscle during contraction by functioning as molecular shock absorbers, but direct evidence for this role is lacking.

Dr. Ervasti will test the hypothesis that dystrophin and utrophin act as shock absorbers by mechanically characterizing both proteins. His results will offer a new understanding into the functional similarities and differences between dystrophin and utrophin in normal muscle and inform development of dystrophin gene-targeted therapies and other drugs (including utrophin-promoting drugs) that might be used to replace the function of dystrophin in DMD.

“Understanding how muscle stem cells interact with their niche is hugely important. It will help us understand how muscle stem cells become dysfunctional during muscular dystrophy. It will help us understand how stem cells form new niches, how these cells self-renew, and ultimately how skeletal muscles regenerate more efficiently.”

Michael Hicks, PhD, a postdoctoral fellow in Microbiology, Immunology, and Molecular Genetics at the University of California, Los Angeles, was awarded an MDA development grant totaling $210,000 over three years to study the potential of modulating the microenvironment and satellite cell niche in Duchenne muscular dystrophy (DMD) to support muscle stem cells.

DMD is caused by a mutation in the dystrophin gene on the X chromosome that results in little or no production of dystrophin, a protein that is essential for keeping muscle cells intact. Every skeletal muscle fiber has a specialized compartment called the satellite cell (SC) niche, which houses all the components to allow a transplanted donor cell to behave like an SC. An SC is a stem cell that can self-renew and repopulate new skeletal muscle after reoccurring injury. Stem cell therapy offers the potential to introduce into DMD muscle healthy, dystrophin-containing muscle with the capacity to regenerate.

Dr. Hicks will use this new funding to assess whether stem cells can engraft and self-renew in DMD mouse muscle. Using human induced pluripotent stem cells and transgenic mice, he will study the process of how muscle stem cells self-renew after transplantation, hopefully one day applying these tools to develop a long-term therapy for cell replacement in diseased muscle.

“Although digestive symptoms affect quality of life, few studies have focused on understanding their causes or developing therapies to treat them.  Our work will be the first to use an animal model system to study the digestive symptoms of DM.”

Melissa Hinman, PhD, a postdoctoral fellow in Molecular Biology at the University of Oregon in Eugene, was awarded an MDA development grant totaling $210,000 over three years to conduct studies using zebrafish to understand and treat gastrointestinal symptoms of myotonic dystrophy (DM).

While weakness and myotonia (the inability to relax) of voluntary muscles are hallmark symptoms of the disease, DM can affect other parts of the body, too, including the digestive system. Common digestive symptoms include abdominal pain, altered gut movement, constipation, diarrhea, and changes in gut bacteria. Gastrointestinal symptoms in DM type 1 (DM1) are prevalent and are consistently reported as one of the most distressing aspects of the disease. However, very little research in this area exists.

Using this grant funding, Dr. Hinman will study defects in gut motility, intestinal barrier function, microbiota, and inflammation in DM1 zebrafish models that she has developed. Dr. Hinman will use her zebrafish model to test whether treatment with specific types of bacteria or drugs improves digestive symptoms. She hopes this will improve understanding of the mechanisms behind DM-related digestive symptoms and potentially identify candidate treatments.

“Given the high burden of cardiomyopathy in DMD patients, it is vital to identify the pathophysiological mechanisms in place in an effort to develop ways to effectively improve cardiac dysfunction and prevent muscular damage.”

Changwon Kho, PhD, assistant professor of Cardiology at the Icahn School of Medicine at Mount Sinai in New York, was awarded an MDA research grant totaling $300,000 over three years to study the SUMO1 protein as a therapeutic target for Duchenne muscular dystrophy (DMD).

DMD is caused by a mutation in the dystrophin gene on the X chromosome that results in little or no production of dystrophin, a protein that is essential for keeping muscle cells intact. Patients with DMD typically have cardiac complications, and heart failure is the major cause of death in DMD. It was recently discovered that the small ubiquitin-like modifier type 1 protein (SUMO1) pathway is defective in dystrophic hearts with established cardiomyopathy. In preliminary studies, Dr. Kho demonstrated that increasing activity of SUMO1, a naturally occurring protein, can restore calcium balance and cardiac function in DMD mice.

With this current funding, Dr. Kho will validate SUMO1 as a target and then begin to test candidate SUMO1 activators in a mouse model of DMD heart disease, aiming to provide a critical foundation for targeting the SUMO1 pathway as a treatment for DMD.

“My focus in the genetics of neuromuscular diseases is to discover novel disease genes [and] mechanisms and build resources to better interpret rare variants discovered in known disease genes.”

Monkol Lek, PhD, assistant professor of Genetics at Yale University School of Medicine in New Haven, Conn., was awarded an MDA research grant totaling $300,000 over three years to improve the clinical interpretation of rare genetic variants identified in limb-girdle muscular dystrophy (LGMD) and congenital muscular dystrophy (CMD).

Despite advances in genetic technologies, only approximately 50% of individuals with rare neuromuscular diseases get a definitive genetic diagnosis. In Dr. Lek’s previously awarded MDA development grant, he was able to increase the diagnosis rate for LGMD through whole-genome sequencing and identify novel neuromuscular disease genes.

Still, even after more sophisticated genetic techniques, not all cases are solvable. Part of the problem is that not enough is known about the significance of rare variants that are difficult to interpret (so-called “variants of unknown significance,” or VUS). The research in this proposal aims to help decode some of those VUS.

Dr. Lek will use genome editing to introduce these VUS into cells and then develop a high-throughput assay in order to interpret the effect of those mutations. He will initially focus on two groups of neuromuscular diseases — collagenopathies and dystroglycanopathies — because the gene products related to these groups of diseases are typically expressed on the surface of muscle cells, making them easily accessible for high-throughput analysis and further functional studies.

“We expect that we will be able to use this model to better understand the role that inflammation plays in developing IBM pathology. We hope that we will be able to use this model to develop and test novel therapeutics for IBM patients.”

Thomas Lloyd, MD, PhD, associate professor of Neurology at Johns Hopkins University School of Medicine in Baltimore, was awarded an MDA research grant totaling $300,000 over three years to study muscle regeneration in a mouse model of inclusion body myositis (IBM).

Inclusion body myositis (IBM) is characterized by muscle inflammation, weakness, and atrophy (wasting). It is one of the idiopathic inflammatory myopathies, a group of disorders characterized by inflammation of the skeletal muscle.

Because one of the biggest barriers to therapy development in sporadic IBM (sIBM) has been the lack of animal models, Dr. Lloyd has created a model by transplanting sIBM muscle tissue from human biopsies into mice. As a new MDA grantee, Dr. Lloyd will study the interaction of the immune system and muscle regeneration in these mice and then screen for potential therapeutic strategies.

Jordi Magrane, PhD, associate professor of Neuroscience at Weill Cornell Medical College in New York, was awarded an MDA research grant totaling $300,000 over three years to study the effect of frataxin protein deficiency in different cell types on the survival of sensory neurons in Friedreich’s ataxia (FA).

In FA, mutations in the frataxin gene (FXN) cause decreased production of frataxin protein, resulting in diminished energy production in cells, including those of the nervous system and heart. Dr. Magrane was previously awarded MDA early-in-career funding to study defects in mitochondrial axonal transport in amyotrophic lateral sclerosis (ALS) motor neurons. He will apply knowledge gained from that work to this new funding.

In this new work, Dr. Magrane will use animal models and cells from FA patients to investigate whether the preferential loss of large myelinated sensory neurons in FA is due to intrinsic properties of the neurons themselves or to interactions with the Schwann cells that provide their myelin. Successful completion of this project will help discover and possibly validate new targets for therapeutic intervention in FA.

Bradley Olwin, PhD, professor of Molecular, Cellular, and Developmental Biology at the University of Colorado Boulder, was awarded an MDA research grant totaling $300,000 over three years to study the regulation of TDP-43 protein aggregates in normal and diseased skeletal muscle.

Over the past decade, the role of TDP-43 disregulation and aggregation in nerve cells in neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) has become increasingly clear. In 1998, Dr. Olwin published work indicating TDP-43 had important roles in muscle cells as well. 

This current grant funding will allow Dr. Olwin to build upon that novel work and study the dynamics of how TDP-43 myogranules (TDP-43-containing aggregates) form and dissolve in muscle cells normally, and in the context of diseases such as inclusion body myositis (IBM), an inflammatory myopathy. Understanding whether TDP-43 myogranules are functional or detrimental to muscle cells will be informative not just for IBM but also for other drug-development efforts focused on decreasing aggregation of TDP-43 (for example, in ALS and frontotemporal dementia).

“Our research aims to develop unbiased experimental strategies and tools to systematically address critical roadblocks in the identification and functional annotation of causative disease alleles in neuromuscular diseases.”

Wolfgang Pernice, PhD, a postdoctoral fellow in Neurology at Columbia University Medical Center in New York, was awarded an MDA development grant totaling $210,000 over three years to more accurately associate rare genetic variants to multiple neuromuscular diseases (NMDs).

For many major NMD categories, the causative gene can be identified in less than 50% of the cases. One of the complicating factors is that in many cases, rare gene variants are identified, but it’s unknown if a variant causes the disease or is harmless. Lacking are efficient, unbiased experimental strategies to systematically evaluate the relevance of these individual variants in disease. Likewise, it’s not known how many of these genes function in healthy individuals.

As a new MDA grantee, Dr. Pernice will use a novel imaging-based method and advanced machine learning to screen for disease-associated phenotypes in patient-derived cells with genetically confirmed NMDs, including Charcot-Marie-Tooth disease and mitochondrial myopathies. This method will allow him to establish a reference dataset by which to directly compare and evaluate new candidate mutations and conduct pharmacological screens for potentially therapeutic agents.

Jeffrey D. Rothstein, MD, PhD, director of the Brain Science Institute and director of the Robert Packard Center for ALS Research at Johns Hopkins University School of Medicine in Baltimore, was awarded an MDA research grant totaling $300,000 over three years to investigate the mechanism of cell-specific injury in C9ORF72-related amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD).

ALS is a progressive neuromuscular disease that destroys muscle-controlling nerve cells called motor neurons. In 2011, it was discovered that a defect in the C9ORF72 gene where one segment of the gene is repeated too many times — also known as a repeat expansion — is the most common cause of the familial form of ALS and is found in some sporadic cases as well. In some patients, the C9ORF72 mutation leads to both ALS and FTD, while in others it leads to FTD only for reasons still unknown.

In a series of previous grants, Dr. Rothstein compared induced pluripotent stem (iPS) cells from people with C9ORF72-ALS to cells from unaffected individuals to find a molecular signature, or biomarker, for the disease-causing effects of the mutant gene. In later MDA-funded work, he used ALS patient-derived stem cells to investigate the role of nuclear dysfunction in ALS caused by C9ORF72 mutations, with the aim of uncovering novel drug targets for ALS. His most recent grant was for Answer ALS, a nationwide consortium that is building a tool for data integration and characterization of disease networks in ALS.

In this newly awarded MDA grant, Dr. Rothstein will identify pathways behind cortical neuron degeneration in FTD versus spinal neuron degeneration in ALS by using human iPS cell-derived forebrain neurons and spinal motor neurons from patients diagnosed with C9ORF72-FTD and ALS/FTD. These studies will help to identify common cellular mechanisms of neurodegeneration in FTD and ALS as well as pathways unique to each cell type, which will better inform the design of therapeutic intervention in both diseases.

Ashlyn Spring, PhD, a postdoctoral fellow in Biological and Genome Sciences at the University of North Carolina at Chapel Hill, was awarded an MDA development grant totaling $210,000 over three years to study the relationship of immune system dysfunction in spinal muscular atrophy (SMA).

SMA is caused by a mutated or missing survival motor neuron 1 gene (SMN1) that prevents the body from making enough survival motor neuron protein (SMN), ultimately leading to the loss of motor neurons, muscle weakness, and paralysis seen in SMA. Previous findings suggest that the immune system is also dysfunctional in patients with SMA, making them more susceptible to infection. However, while major strides have been made in developing and approving therapies to treat the genetic mutations behind SMA, little is known about how the immune system dysfunction affects other tissues.

In this project, Dr. Spring, a first-time MDA grantee, will use fly, mouse, and human cell line models of SMA to investigate how the immune system’s response to infections is impacted in the disease. This work will lead to an understanding of why SMN1 mutations change immune system function as well as help identify targets for new therapeutics to improve treatment of SMA in the future.

Charlotte Sumner, MD, professor of Neurology and Neuroscience at Johns Hopkins University School of Medicine in Baltimore, was awarded an MDA research grant totaling $300,000 over three years to study the role of mutations in the transient receptor potential vanilloid 4 gene (TRPV4) in causing one type of Charcot-Marie-Tooth disease (CMT) and distal spinal muscular atrophy (SMA).

CMT is characterized by the degeneration of peripheral nerves, resulting in disabling muscle weakness and sensory loss. One form of the disease, CMT type 2C (CMT2C), is caused by mutations in TRPV4, which codes for a cellular membrane channel protein that helps control the flow of calcium in and out of cells. Mutations in TRPV4 cause CMT2C and distal SMA, revealing an unexpected role for this Ca2+-permeable channel in neurodegeneration.

In previous MDA-funded research, Dr. Sumner generated fly and mouse models of CMT2C in order to better understand the mechanisms of disease. With this newest MDA grant, Dr. Sumner will focus on the role that TRPV4 may play in endothelial cells regulating the blood-nerve barrier. Defining the mechanisms by which TRPV4 mutations cause neuropathy is important because TRPV4 protein is a readily druggable therapeutic target — it is expressed at the plasma membrane and small molecules acting on it already exist.

“To date, not many labs have probed the underlying nature of genetically inherited diseases using optical tweezer techniques. We are excited in setting a precedent to deliver such first time molecular biophysical studies.”

Alireza Mashaghi Tabari, PhD, assistant professor of Systems Biomedicine and Pharmacology at Leiden University in the Netherlands, was awarded an MDA research grant totaling $300,000 over three years to study how altered protein folding of the androgen receptor influences the pathology of spinal-bulbar muscular atrophy (SBMA).

SBMA is a genetic disorder in which loss of motor neurons — nerve cells in the spinal cord and brainstem — affects the part of the nervous system that controls voluntary muscle movement. SBMA is caused by repeat expansions in the androgen receptor gene. (A repeat expansion is a genetic defect where one segment of the gene is repeated too many times.) Mutations in the androgen receptor in SBMA alter protein folding, cell signaling, and protein aggregation for unknown reasons.

Chaperone proteins are key to protein folding and the removal of damaged, misfolded proteins. As a new MDA researcher, Dr. Mashaghi Tabari will use sensitive single-molecule approaches to understand how the structure of the androgen receptor is altered in SBMA, and specifically how chaperones are involved in the changes. These studies might inform therapy development for SBMA and other neuromuscular diseases where protein misfolding is involved.

Davide Trotti, PhD, professor of Neuroscience at Thomas Jefferson University in Philadelphia, was awarded an MDA research grant totaling $300,000 over three years to investigate the mechanism by which the toxic mutations in C9ORF72-amyotrophic lateral sclerosis (ALS) contribute to the degradation of the neuromuscular junction (NMJ).

ALS is a progressive neuromuscular disease that destroys muscle-controlling nerve cells called motor neurons. Normally, nerve cells communicate with muscle cells by sending electrical signals across the NMJ. Neuromuscular junction disorders result from the destruction, malfunction, or absence of one or more key proteins involved in the transmission of signals between muscles and nerves. Frequently, disruption of this communication happens early in the course of ALS.

In 2011, researchers found that a mutation in the C9ORF72 gene where one segment is repeated too many times — otherwise known as a repeat expansion — is the most common cause of familial (inherited) ALS and is also found in sporadic (not inherited) cases. Although mutations in C9ORF72 represent the most common cause of ALS, little is known about the mechanisms by which these mutations impair neuromuscular communication at the NMJ.

In previous MDA-funded work, Dr. Trotti studied how the accumulation of protein clumps in patients with C9ORF72-ALS may contribute to motor neuron death. Using rodent and C9ORF72-ALS patient induced pluripotent stem cell models, Dr. Trotti will identify the NMJ pathogenic changes caused by C9ORF72-related toxic dipeptide proteins that lead to this loss of motor neuron-muscle connectivity in C9ORF72-ALS.

“This work will further advance pre-clinical development of our gene editing therapy for Duchenne. Assessing the immune response will allow for safety to be assessed and strategies to re-dose the therapy to be developed, which would greatly increase the efficacy and applicability of the therapy.”

Courtney Young, PhD, CEO of MyoGene Bio LLC in Los Angeles, was awarded an MDA research grant totaling $299,592 over three years to assess the immune response to repeated dosing of adeno-associated virus-dependent gene-replacement therapy in Duchenne muscular dystrophy (DMD).

DMD is caused by a mutation in the dystrophin gene on the X chromosome that results in little or no production of the protein dystrophin. Currently, gene-replacement and gene-editing (for example, the CRISPR gene-editing system) therapies rely on the adeno-associated virus (AAV) to deliver the replacement gene or gene-editing program to a patient’s cells. However, the virus can trigger an immune response in the body, so patients either have pre-existing immunity or will develop it after the first dose — ultimately preventing repeated dosing of the therapy.

At MyoGene Bio, Dr. Young and team have developed a gene-editing therapy using CRISPR/Cas9 aimed at allowing the production of dystrophin, and they have demonstrated the therapy can restore dystrophin in human cells and in mice. To safely enable repeated exposure to AAV, Dr. Young, who is an MDA early-in-career investigator, will develop an immunosuppressive protocol using humanized DMD mice to characterize the adaptive immune response to single and repeated exposures of AAV-CRISPR. Importantly, this work can inform practices not just in DMD but also across a wide array of diseases utilizing AAV-based gene therapy and gene editing.

“The study of patients’ walking patterns in their day-to-day life can help researchers and clinicians better understand how the pathomechanics of SMA and DMD gaits are affected by newly available treatments.”

Damiano Zanotto, PhD, assistant professor of Mechanical Engineering at the Stevens Institute of Technology in Hoboken, N.J., was awarded an MDA research grant totaling $200,000 over two years to evaluate the potential of wearable technology to assess gait function in spinal muscular atrophy (SMA) and Duchenne muscular dystrophy (DMD).

SMA and DMD are genetic disorders that cause progressive muscle weakness and impaired function. While recently approved therapies and treatments are now available to treat both disorders, the impact of these medicines on real-world function is not well known. The study of patients’ walking patterns in their day-to-day living environments can help researchers and clinicians better understand how motor performance in SMA and DMD is affected by these diseases and their new treatments.

Preliminary findings have shown that machine learning methods may transform noisy signals from wearable body sensors into measurable parameters of gait. Using this funding, Dr. Zanotto will develop novel instrumented insoles that can accurately measure gait over many hours and in any environment, providing a more affordable and versatile instrument to measure gait and balance in neuromuscular disorders. It will also make it possible to measure subtle but meaningful changes in gait that may reflect patients’ responsiveness to treatments. He hopes this research will lead to future clinical studies of how gait function in SMA and DMD is affected by new disease-modifying treatments.