Dystrophin Gene Research Articles

Lentiviral Micro-dystrophin Gene Treatment into Late-stage mdx Mice for Duchenne Muscular Dystrophy Disease.

Duchenne Muscular Dystrophy (DMD) results in a deficiency of dystrophin expression in patient muscle fibers, leading to progressive muscle degeneration. Treatment of DMD has undertaken current transformation with the advancement of novel gene therapy and molecular biology techniques, which are secure, well-tolerated, and effective therapeutic approaches. DMD gene therapies have mainly focused on young DMD patients as in vivo animal model trials have been performed in 0-1-month DMD mice. However, it has not yet been answered how micro-dystrophin encoding lentiviral treatment affects Dystrophin expression and DMD symptoms in 10-month mdx mice. We planned to integrate the micro-Dystrophin gene sequence into the muscle cells by viral transfer, using micro-Dystrophin-encoding lentivirus to reduce the dystrophic pathology in late-stage dmd mice. The histopathological and physiological-functional regeneration activities of the lentiviralmicro- Dystrophin gene therapy methods were compared, along with changes in temporal Dystrophin expression and their functionality, toxicity, and gene expression level. Here, we showed that the micro-dystrophin transgene transfers intramuscularly and intraperitoneally in late-stage dmd-mdx-4cv mice restored dystrophin expression in the skeletal and cardiac muscle (p <0.001). Furthermore, motor performance analysis, including hanging and tracking tests, improved statistically significantly after the treatment (p <0.05). Consequently, this study suggests that patients in the late stages of muscular dystrophy can benefit from lentiviral micro-dystrophin gene therapies to present an improvement in dystrophic muscle pathology.

IPSC derived cardiac fibroblasts of DMD patients show compromised actin microfilaments, metabolic shift and pro-fibrotic phenotype

Duchenne muscular dystrophy (DMD) is a severe form of muscular dystrophy caused by mutations in the dystrophin gene. We characterized which isoforms of dystrophin were expressed by human induced pluripotent stem cell (hiPSC)-derived cardiac fibroblasts obtained from control and DMD patients. Distinct dystrophin isoforms were observed; however, highest molecular weight isoform was absent in DMD patients carrying exon deletions or mutations in the dystrophin gene. The loss of the full-length dystrophin isoform in hiPSC-derived cardiac fibroblasts from DMD patients resulted in deficient formation of actin microfilaments and a metabolic switch from mitochondrial oxidation to glycolysis. The DMD hiPSC-derived cardiac fibroblasts exhibited a dysregulated mitochondria network and reduced mitochondrial respiration, with enhanced compensatory glycolysis to sustain cellular ATP production. This metabolic remodeling was associated with an exacerbated myofibroblast phenotype and increased fibroblast activation in response to pro fibrotic challenges. As cardiac fibrosis is a critical pathological feature of the DMD heart, the myofibroblast phenotype induced by the absence of dystrophin may contribute to deterioration in cardiac function. Our study highlights the relationship between cytoskeletal dynamics, metabolism of the cell and myofibroblast differentiation and provides a new mechanism by which inactivation of dystrophin in non-cardiomyocyte cells may increase the severity of cardiopathy.

Targeting Duchenne muscular dystrophy by skipping DMD exon 45 with base editors

Duchenne muscular dystrophy is an X-linked monogenic disease caused by mutations in the dystrophin gene (DMD) characterized by progressive muscle weakness, leading to loss of ambulation and decreased life expectancy. Since the current standard of care for Duchenne muscular dystrophy is to merely treat symptoms, there is a dire need for treatment modalities that can correct the underlying genetic mutations. While several gene replacement therapies are being explored in clinical trials, one emerging approach that can directly correct mutations in genomic DNA is base editing. We have recently developed CRISPR-SKIP, a base editing strategy to induce permanent exon skipping by introducing C > T or A > G mutations at splice acceptors in genomic DNA, which can be used therapeutically to recover dystrophin expression when a genomic deletion leads to an out-of-frame DMD transcript. We now demonstrate that CRISPR-SKIP can be adapted to correct some forms of Duchenne muscular dystrophy by disrupting the splice acceptor in human DMD exon 45 with high efficiency, which enables open reading frame recovery and restoration of dystrophin expression. We also demonstrate that AAV-delivered split-intein base editors edit the splice acceptor of DMD exon 45 in cultured human cells and invivo, highlighting the therapeutic potential of this strategy.

When Size Really Matters: The Eccentricities of Dystrophin Transcription and the Hazards of Quantifying mRNA from Very Long Genes.

At 2.3 megabases in length, the dystrophin gene is enormous: transcription of a single mRNA requires approximately 16 h. Principally expressed in skeletal muscle, the dystrophin protein product protects the muscle sarcolemma against contraction-induced injury, and dystrophin deficiency results in the fatal muscle-wasting disease, Duchenne muscular dystrophy. This gene is thus of key clinical interest, and therapeutic strategies aimed at eliciting dystrophin restoration require quantitative analysis of its expression. Approaches for quantifying dystrophin at the protein level are well-established, however study at the mRNA level warrants closer scrutiny: measured expression values differ in a sequence-dependent fashion, with significant consequences for data interpretation. In this manuscript, we discuss these nuances of expression and present evidence to support a transcriptional model whereby the long transcription time is coupled to a short mature mRNA half-life, with dystrophin transcripts being predominantly nascent as a consequence. We explore the effects of such a model on cellular transcriptional dynamics and then discuss key implications for the study of dystrophin gene expression, focusing on both conventional (qPCR) and next-gen (RNAseq) approaches.

Phenotypic features of dystrophin gene knockout pigs harboring a human artificial chromosome containing the entire dystrophin gene

Mammalian artificial chromosomes have enabled the introduction of extremely large amounts of genetic information into animal cells in an autonomously replicating, nonintegrating format. However, the evaluation of human artificial chromosomes (HACs) as novel tools for curing intractable hereditary disorders has been hindered by the limited efficacy of the delivery system. We generated dystrophin gene knockout (DMD-KO) pigs harboring the HAC bearing the entire human DMD via asomatic cell cloning procedure (DYS-HAC-cloned pig). Restored human dystrophin expression was confirmed by immunofluorescence staining in the skeletal muscle of the DYS-HAC-cloned pigs. Viability at the first month postpartum of the DYS-HAC-cloned pigs, including motor function in the hind leg and serum creatinine kinase level, was improved significantly when compared with that in the original DMD-KO pigs. However, decrease in systemic retention of the DYS-HAC vector and limited production of the DMD protein might have caused severe respiratory impairment with general prostration by 3months postpartum. The results demonstrate that the use of transchromosomic cloned pigs permitted a straightforward estimation of the efficacy of the DYS-HAC carried in affected tissues/organs in a large-animal disease model, providing novel insights into the therapeutic application of exogenous mammalian artificial chromosomes.

Prevention of early-onset cardiomyopathy in Dmd exon 52–54 deletion mice by CRISPR-Cas9-mediated exon skipping

Duchenne muscular dystrophy (DMD) is a disease with a life-threatening trajectory resulting from mutations in the dystrophin gene, leading to degeneration of skeletal muscle and fibrosis of cardiac muscle. The overwhelming majority of mutations are multiexonic deletions. We previously established a dystrophic mouse model with deletion of exons 52-54 in Dmd that develops an early-onset cardiac phenotype similar to DMD patients. Here we employed CRISPR-Cas9 delivered intravenously by adeno-associated virus (AAV) vectors to restore functional dystrophin expression via excision or skipping of exon 55. Exon skipping with a solitary guide significantly improved editing outcomes and dystrophin recovery over dual guide excision. Some improvements to genomic and transcript editing levels were observed when the guide dose was enhanced, but dystrophin restoration did not improve considerably. Editing and dystrophin recovery were restricted primarily to cardiac tissue. Remarkably, our exon skipping approach completely prevented onset of the cardiac phenotype in treated mice up to 12weeks. Thus, our results demonstrate that intravenous delivery of a single-cut CRISPR-Cas9-mediated exon skipping therapy can prevent heart dysfunction in DMD invivo.

Drug-refractory Heart Failure in Female Carrier of Duchenne Muscular Dystrophy: A Case of X-linked Dilated Cardiomyopathy.

A 56-year-old woman was referred to our hospital for the further evaluation of drug-refractory heart failure with a reduced ejection fraction. A family history interview revealed that men in her family had died of Duchenne muscular dystrophy (DMD), whereas she had no skeletal muscle disorder. Myocardial histopathology revealed a reduced dystrophin expression in the cardiomyocyte membrane, and a dystrophin (DMD) gene analysis identified a duplication in exon 8-9 on Xp21, suggesting that she had a cardiac-specific phenotype of dystrophinopathy, i.e. X-linked dilated cardiomyopathy (XLDCM). In conclusion, careful family history interviews and an investigation of dystrophinopathy are required to detect XLDCM in women.

Pamrevlumab, a Fully Human Monoclonal Antibody Targeting Connective Tissue Growth Factor, for Non-Ambulatory Patients with Duchenne Muscular Dystrophy.

Duchenne muscular dystrophy (DMD) is a neuromuscular disease stemming from dystrophin gene mutations. Lack of dystrophin leads to progressive muscle damage and replacement of muscle with fibrotic and adipose tissue. Pamrevlumab (FG-3019), a fully human monoclonal antibody that binds to connective tissue growth factor (CTGF), is in Phase III development for treatment of DMD and other diseases. MISSION (Study 079; NCT02606136) was an open-label, Phase II, single-arm trial of pamrevlumab in 21 non-ambulatory patients with DMD (aged≥12 years, receiving corticosteroids) who received 35-mg/kg intravenous infusions every 2 weeks for 2 years. The primary endpoint was change from baseline in percent predicted forced vital capacity (ppFVC). Secondary endpoints included other pulmonary function tests, upper limb function and strength assessments, and changes in upper arm fat and fibrosis scores on magnetic resonance imaging. Fifteen patients completed the trial. Annual change from baseline (SE) in ppFVC was -4.2 (0.7) (95% CI -5.5, -2.8). Rate of decline in ppFVC in pamrevlumab-treated patients was slower than observed in historical published trials of non-ambulatory patients. MISSION participants experienced slower-than-anticipated muscle function declines compared with natural history and historical published trials of non-ambulatory patients with DMD. Pamrevlumab was well-tolerated. Treatment-emergent adverse events were mild to moderate, and none led to study discontinuation. nti-CTGF therapy with pamrevlumab represents a potential treatment for DMD. The lack of internal control group limits the results.

ACTIVE ASSISTED MOVEMENT DALAM MENJAGA KEMAMPUAN FUNGSIONAL PADA KONDISI DUCHENNE MUSCULAR DYSTROPHY

Background: Duchenne muscular dystrophy which is a recessive x-linked disorder that often affects males. Duchenne muscular dystrophy is caused by mutations in the dystrophin gene at the Xp21 locus so that dystrophin protein is not produced or dystrophin deficiency and structural abnormalities occur. Dystrophinopathies are X-linked recessive disorders affecting 1 in 5,000 to 1 in 6,000 live male births. The prevalence of DMD is less than 10 cases per 100,000 males. Objective: Physiotherapy management in this case aims to determine the benefits of providing physiotherapy interventions in the form of active assisted and passive movement and stretching in patients with Duchenne muscular dystrophy. Methods: This case report was conducted at PLDPI Surakarta by taking patients with Duchenne muscular dystrophy cases by providing physiotherapy modalities in the form of active assisted and passive movement and stretching for 3 physiotherapy sessions. Furthermore, measurements were taken with the GMFM and XOTR Scale in the first to third physiotherapy. Results: From the physiotherapy management given, it was found that functional ability and muscle strength remained unchanged and did not develop. Conclusion: Physiotherapy management in this case report is proven to be able to maintain functional ability and muscle strength in patients with Duchenne muscular dystrophy.

Duchenne muscular dystrophy: disease mechanism and therapeutic strategies.

Duchenne muscular dystrophy (DMD) is a severe, progressive, and ultimately fatal disease of skeletal muscle wasting, respiratory insufficiency, and cardiomyopathy. The identification of the dystrophin gene as central to DMD pathogenesis has led to the understanding of the muscle membrane and the proteins involved in membrane stability as the focal point of the disease. The lessons learned from decades of research in human genetics, biochemistry, and physiology have culminated in establishing the myriad functionalities of dystrophin in striated muscle biology. Here, we review the pathophysiological basis of DMD and discuss recent progress toward the development of therapeutic strategies for DMD that are currently close to or are in human clinical trials. The first section of the review focuses on DMD and the mechanisms contributing to membrane instability, inflammation, and fibrosis. The second section discusses therapeutic strategies currently used to treat DMD. This includes a focus on outlining the strengths and limitations of approaches directed at correcting the genetic defect through dystrophin gene replacement, modification, repair, and/or a range of dystrophin-independent approaches. The final section highlights the different therapeutic strategies for DMD currently in clinical trials.

Dystrophic cardiomyopathy: role of the cardiac myofilaments.

Dystrophic cardiomyopathy arises from mutations in the dystrophin gene. Dystrophin forms part of the dystrophin glycoprotein complex and is postulated to act as a membrane stabilizer, protecting the sarcolemma from contraction-induced damage. Duchenne muscular dystrophy (DMD) is the most severe dystrophinopathy, caused by a total absence of dystrophin. Patients with DMD present with progressive skeletal muscle weakness and, because of treatment advances, a cardiac component of the disease (i.e., dystrophic cardiomyopathy) has been unmasked later in disease progression. The role that myofilaments play in dystrophic cardiomyopathy is largely unknown and, as such, this study aimed to address cardiac myofilament function in a mouse model of muscular dystrophy. To assess the effects of DMD on myofilament function, isolated permeabilized cardiomyocytes of wild-type (WT) littermates and Dmdmdx-4cv mice were attached between a force transducer and motor and subjected to contractile assays. Maximal tension and rates of force development (indexed by the rate constant, k tr) were similar between WT and Dmdmdx-4cv cardiac myocyte preparations. Interestingly, Dmdmdx-4cv cardiac myocytes exhibited greater sarcomere length dependence of peak power output compared to WT myocyte preparations. These results suggest dystrophin mitigates length dependence of activation and, in the absence of dystrophin, augmented sarcomere length dependence of myocyte contractility may accelerate ventricular myocyte contraction-induced damage and contribute to dystrophic cardiomyopathy. Next, we assessed if mavacamten, a small molecule modulator of thick filament activation, would mitigate contractile properties observed in Dmdmdx-4cv permeabilized cardiac myocyte preparations. Mavacamten decreased maximal tension and k tr in both WT and Dmdmdx-4cv cardiac myocytes, while also normalizing the length dependence of peak power between WT and Dmdmdx-4cv cardiac myocyte preparations. These results highlight potential benefits of mavacamten (i.e., reduced contractility while maintaining exquisite sarcomere length dependence of power output) as a treatment for dystrophic cardiomyopathy associated with DMD.

Production of Duchenne muscular dystrophy cellular model using CRISPR-Cas9 exon deletion strategy.

Duchenne Muscular Dystrophy (DMD) is a progressive muscle wasting disorder caused by loss-of-function mutations in the dystrophin gene. Although the search for a definitive cure has failed to date, extensive efforts have been made to introduce effective therapeutic strategies. Gene editing technology is a great revolution in biology, having an immediate application in the generation of research models. DMD muscle cell lines are reliable sources to evaluate and optimize therapeutic strategies, in-depth study of DMD pathology, and screening the effective drugs. However, only a few immortalized muscle cell lines with DMD mutations are available. In addition, obtaining muscle cells from patients also requires an invasive muscle biopsy. Mostly DMD variants are rare, making it challenging to identify a patient with a particular mutation for a muscle biopsy. To overcome these challenges and generate myoblast cultures, we optimized a CRISPR/Cas9 gene editing approach to model the most common DMD mutations that include approximately 28.2% of patients. GAP-PCR and sequencing results show the ability of the CRISPR-Cas9 system to efficient deletion of mentioned exons. We showed producing truncated transcript due to the targeted deletion by RT-PCR and sequencing. Finally, mutation-induced disruption of dystrophin protein expression was confirmed by western blotting. All together, we successfully created four immortalized DMD muscle cell lines and showed the efficacy of the CRISPR-Cas9 system for the generation of immortalized DMD cell models with the targeted deletions.

Development of a Gene and Nucleic Acid Delivery System for Skeletal Muscle Administration via Limb Perfusion Using Nanobubbles and Ultrasound.

Strategies for gene and nucleic acid delivery to skeletal muscles have been extensively explored to treat Duchenne muscular dystrophy (DMD) and other neuromuscular diseases. Of these, effective intravascular delivery of naked plasmid DNA (pDNA) and nucleic acids into muscles is an attractive approach, given the high capillary density in close contact with myofibers. We developed lipid-based nanobubbles (NBs) using polyethylene-glycol-modified liposomes and an echo-contrast gas and found that these NBs could improve tissue permeability by ultrasound (US)-induced cavitation. Herein, we delivered naked pDNA or antisense phosphorodiamidate morpholino oligomers (PMOs) into the regional hindlimb muscle via limb perfusion using NBs and US exposure. pDNA encoding the luciferase gene was injected with NBs via limb perfusion into normal mice with application of US. High luciferase activity was achieved in a wide area of the limb muscle. DMD model mice were administered PMOs, designed to skip the mutated exon 23 of the dystrophin gene, with NBs via intravenous limb perfusion, followed by US exposure. The number of dystrophin-positive fibers increased in the muscles of mdx mice. Combining NBs and US exposure, which can be widely delivered to the hind limb muscles via the limb vein, could be an effective therapeutic approach for DMD and other neuromuscular disorders.

Increasing muscle contractility through low-frequency stimulation alters tibial bone geometry and reduces bone strength in mdx and dko dystrophic mice.

Duchenne muscular dystrophy (DMD) is a severe muscle wasting disease caused by mutations or deletions in the dystrophin gene, for which there remains no cure. As DMD patients also develop bone fragility because of muscle weakness and immobilization, better understanding of the pathophysiological mechanisms of dystrophin deficiency will help develop therapies to improve musculoskeletal health. Since alterations in muscle phenotype can influence bone structure, we investigated whether modifying muscle contractile activity through low-frequency stimulation (LFS) could alter bone architecture in mouse models of DMD. We tested the hypothesis that increasing muscle contractile activity could influence bone mass and structure in dystrophin-deficient (mdx) and dystrophin- and utrophin-deficient (dko) dystrophic mice. Tibial bone structure in dko mice was significantly different from that in mdx and wild-type (C57BL/10) control mice. Effects of LFS on bone architecture differed between dystrophic and healthy mice, with LFS thinning cortical bone in both dystrophic models. Bone mass was maintained in LFS-treated healthy mice, with a reduced proportion of high-density bone and concomitant increase in low-density bone. LFS-treated dko mice exhibited a net deficit in cortical thickness and reduced high-density bone but no equivalent increase in low-density bone. These alterations in bone structure and mineral density reduced mechanical strength in mdx and dko mice. The findings reveal that muscle activity can regulate bone mass, structure, mineral accrual, and strength, especially in the context of dystrophin and/or utrophin deficiency. The results provide unique insights into the development of bone fragility in DMD and for devising interventions to improve musculoskeletal health.NEW & NOTEWORTHY Patients with Duchenne muscular dystrophy (DMD) develop bone fragility because of muscle weakness and immobilization. We investigated whether increasing muscle contractile activity through low-frequency stimulation (LFS) could alter bone architecture in dystrophin-deficient (mdx) or dystrophin- and utrophin-deficient (dko) mouse models of DMD. Chronic LFS reduced tibial diaphysis cross sections in mdx and dko mice, without affecting bone shape in healthy mice. LFS affected the distribution of bone mineral density across all phenotypes, with the magnitude of effect being dependent on disease severity.

Design of bacteriophage T4-based artificial viral vectors for human genome remodeling

Designing artificial viral vectors (AVVs) programmed with biomolecules that can enter human cells and carry out molecular repairs will have broad applications. Here, we describe an assembly-line approach to build AVVs by engineering the well-characterized structural components of bacteriophage T4. Starting with a 120 × 86 nm capsid shell that can accommodate 171-Kbp DNA and thousands of protein copies, various combinations of biomolecules, including DNAs, proteins, RNAs, and ribonucleoproteins, are externally and internally incorporated. The nanoparticles are then coated with cationic lipid to enable efficient entry into human cells. As proof of concept, we assemble a series of AVVs designed to deliver full-length dystrophin gene or perform various molecular operations to remodel human genome, including genome editing, gene recombination, gene replacement, gene expression, and gene silencing. These large capacity, customizable, multiplex, and all-in-one phage-based AVVs represent an additional category of nanomaterial that could potentially transform gene therapies and personalized medicine.

Restoration of brain dystrophin using tricyclo-DNA ASOs restores neurobehavioral deficits in DMD mice

Restoration of brain dystrophin using tricyclo-DNA ASOs restores neurobehavioral deficits in DMD mice

CFTR and dystrophin encoding plasmids carrying both luciferase reporter gene, nuclear import specific sequences and triple helix sites

Duchenne Muscular Dystrophy and Cystic Fibrosis are two major monogenetic diseases which could be treated by non-viral gene therapy. For this purpose, plasmid DNA (pDNA) coding for the functional genes requires its equipment with signal molecules favouring its intracellular trafficking and delivery in the nucleus of the target cells. Here, two novel constructions of large pDNAs encoding the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) and full-length dystrophin (DYS) genes are reported. The expression of CFTR and DYS genes are driven respectively by the hCEF1 airway epithelial cells and spc5–12 muscle cells specific promoter. Those pDNAs encode also the luciferase reporter gene driven by the CMV promoter to evaluate gene delivery in animals by bioluminescence. In addition, oligopurine • oligopyrimidine sequences are inserted to enable equipment of pDNAs with peptides conjugated with a triple helix forming oligonucleotide (TFO). Furthermore, specific κB sequences are also inserted to promote their NFκB-mediated nuclear import. pDNA constructions are reported; transfection efficiency, tissue specific expression of CFTR and dystrophin in target cells, and triple helix formation are demonstrated. These plasmids are tools of interest to develop non-viral gene therapy of Cystic Fibrosis and Duchenne Muscular Dystrophy.

Evaluation of an AAV9-mini-dystrophin gene therapy candidate in a rat model of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is an X-linked disease caused by loss-of-function mutations in the dystrophin gene and is characterized by muscle wasting and early mortality. Adeno-associated virus-mediated gene therapy is being investigated as a treatment for DMD. In the nonclinical study documented here, we determined the effective dose of fordadistrogene movaparvovec, a clinical candidate adeno-associated virus serotype 9 vector carrying a human mini-dystrophin transgene, after single intravenous injection in a dystrophin-deficient (DMDmdx) rat model of DMD. Overall, we found that transduction efficiency, number of muscle fibers expressing the human mini-dystrophin polypeptide, improvement of the skeletal and cardiac muscle tissue architecture, correction of muscle strength and fatigability, and improvement of diastolic and systolic cardiac function were directly correlated with the amount of vector administered. The effective dose was then tested in older DMDmdx rats with a more dystrophic phenotype similar to the pathology observed in older patients with DMD. Except for a less complete rescue of muscle function in the oldest cohort, fordadistrogene movaparvovec was also found to be therapeutically effective in older DMDmdx rats, suggesting that this product may be appropriate for evaluation in patients with DMD at all stages of disease.

Accumulation of Dystrophin-Positive Muscle Fibers and Improvement of Neuromuscular Junctions in mdx Mouse Muscles after Bone Marrow Transplantation under Different Conditions.

Duchenne muscular dystrophy (DMD) is a severe muscular disorder caused by mutations in the dystrophin gene. It leads to respiratory and cardiac failure and premature death at a young age. Although recent studies have greatly deepened the understanding of the primary and secondary pathogenetic mechanisms of DMD, an effective treatment remains elusive. In recent decades, stem cells have emerged as a novel therapeutic product for a variety of diseases. In this study, we investigated nonmyeloablative bone marrow cell (BMC) transplantation as a method of cell therapy for DMD in an mdx mouse model. By using BMC transplantation from GFP-positive mice, we confirmed that BMCs participate in the muscle restoration of mdx mice. We analyzed both syngeneic and allogeneic BMC transplantation under different conditions. Our data indicated that 3 Gy X-ray irradiation with subsequent BMC transplantation improved dystrophin synthesis and the structure of striated muscle fibers (SMFs) in mdx mice as well as decreasing the death rate of SMFs. In addition, we observed the normalization of neuromuscular junctions (NMJs) in mdx mice after nonmyeloablative BMC transplantation. In conclusion, we demonstrated that nonmyeloablative BMC transplantation could be considered a method for DMD treatment.

Modeling Duchenne Muscular Dystrophy Cardiomyopathy with Patients' Induced Pluripotent Stem-Cell-Derived Cardiomyocytes.

Duchenne muscular dystrophy (DMD) is an X-linked progressive muscle degenerative disease caused by mutations in the dystrophin gene, resulting in death by the end of the third decade of life at the latest. A key aspect of the DMD clinical phenotype is dilated cardiomyopathy, affecting virtually all patients by the end of the second decade of life. Furthermore, despite respiratory complications still being the leading cause of death, with advancements in medical care in recent years, cardiac involvement has become an increasing cause of mortality. Over the years, extensive research has been conducted using different DMD animal models, including the mdx mouse. While these models present certain important similarities to human DMD patients, they also have some differences which pose a challenge to researchers. The development of somatic cell reprograming technology has enabled generation of human induced pluripotent stem cells (hiPSCs) which can be differentiated into different cell types. This technology provides a potentially endless pool of human cells for research. Furthermore, hiPSCs can be generated from patients, thus providing patient-specific cells and enabling research tailored to different mutations. DMD cardiac involvement has been shown in animal models to include changes in gene expression of different proteins, abnormal cellular Ca2+ handling, and other aberrations. To gain a better understanding of the disease mechanisms, it is imperative to validate these findings in human cells. Furthermore, with the recent advancements in gene-editing technology, hiPSCs provide a valuable platform for research and development of new therapies including the possibility of regenerative medicine. In this article, we review the DMD cardiac-related research performed so far using human hiPSCs-derived cardiomyocytes (hiPSC-CMs) carrying DMD mutations.