RARE DISEASE
Congenital muscular dystrophy
Congenital muscular dystrophy
Congenital muscular dystrophy
Synonyms: CMD, MDC
Synonyms: CMD, MDC
Synonyms: CMD, MDC
Drug discovery
4
drugs
With orphan designations
Overview
Congenital muscular dystrophy (CMD) comprises rare genetic neuromuscular disorders presenting at birth/infancy with hypotonia, progressive muscle weakness, and dystrophic muscle pathology. Over 30 subtypes exist, classified by affected genes/proteins (e.g., laminin-α2, collagen VI). Clinical features include contractures, respiratory insufficiency, and variable CNS/ocular involvement. Diagnosis combines clinical assessment, muscle biopsy, and genetic testing [1][7][15].
Burden
Mortality: Respiratory/cardiac complications account for 60-80% of deaths, often in early adulthood [1][9]
Economic impact: Annual per-patient costs exceed $100,000 (USD) when accounting for medical care, assistive devices, and lost caregiver productivity [4][5]
Functional decline: >70% develop scoliosis; 40% require wheelchair dependence by adolescence [5][12][15]
Therapies
Supportive care: Respiratory support, physical therapy, orthopedic interventions (spinal fusion, contracture management) [8][19]
Pharmacologic: Corticosteroids for specific subtypes; investigational gene therapies (exon skipping, CRISPR/Cas9) in preclinical stages [3][13][16]
Multidisciplinary management: Cardiac surveillance, nutritional support, and adaptive equipment [5][11]
Categories: rare genetic diseases, rare neurological diseases
Research Papers
627 drug discovery papers about Congenital muscular dystrophy, with 6 first-in-class and 2 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
627 drug discovery papers about Congenital muscular dystrophy, with 6 first-in-class and 2 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
small molecules
2026-07-27 | Cortical organoids from congenital DM1 PSCs reveal MBNL-dependent corticogenesis defects and enable preclinical testing of therapeutic compounds
ABSTRACT Myotonic dystrophy type 1 (DM1) is caused by an expansion of a CTG repeat in the 3′ untranslated region of the DMPK gene, leading to accumulation of toxic CUG-repeat RNAs, sequestration of MBNL proteins and widespread splicing dysregulation. Congenital DM1 (CDM), the most severe form of the disease, is associated with profound muscular and neurodevelopmental defects, yet the mechanisms underlying early human brain involvement remain poorly understood. Here, we generated cortical organoids from patient-derived pluripotent stem cells carrying >1000 CTG repeats, an expansion typically associated with CDM, to model early human neurodevelopment. DM1 molecular and cellular hallmarks were detected at early developmental stages, including nuclear DMPK RNA foci in neural progenitor cells and reduced proliferative capacity. As organoids matured, CDM cultures displayed altered cortical composition, with reduced CTIP2⁺ and SATB2⁺ neuronal populations and increased NFIA⁺/GFAP⁺ glial cells. In parallel, 120-day-old organoids recapitulated splicing abnormalities previously identified in DM1 patient brain tissue. To assess the contribution of MBNL dysfunction, we analyzed cortical organoids derived from MBNL2 and MBNL1/2/3 knockout induced pluripotent stem cells, which reproduced key neurodevelopmental phenotypes observed in CDM organoids, supporting a central role for MBNL loss of function in impaired corticogenesis. Finally, we evaluated the translational relevance of this model using tideglusib and erythromycin, two compounds currently under clinical evaluation in DM1 patients. Both treatments reduced DMPK RNA foci and restored proliferation defects in SOX2⁺ neural progenitors. Together, these findings establish cortical organoids as a robust human model of CDM-associated neurodevelopmental defects, uncover MBNL-dependent mechanisms underlying early corticogenesis impairment and demonstrate the utility of this platform for translational therapeutic discovery in DM1.
2026-05-13 | Anti-Receptor Activator of Nuclear Factor-κB Ligand Improves Muscle Dysfunction and Strengthens Bone in Laminin-α2-Deficient dy2J/dy2J Dystrophic Mice.
Congenital muscular dystrophy type 1A (CMD1A) is a severe genetic neuromuscular disorder caused by mutations in the LAMA2 gene, which encodes the laminin-α2 subunit, an essential structural protein for maintaining muscle integrity during contraction. Affected children experience progressive muscle damage, hypotonia, delayed motor development, and respiratory tract insufficiency. CMD1A muscles undergo repeated cycles of degeneration and regeneration accompanied by chronic inflammation. Beyond its established role in bone remodeling, the receptor activator of nuclear factor-κB/receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin signaling axis has also been implicated in muscle pathophysiology. A 10-day treatment with full-length osteoprotegerin fused to an Fc fragment was previously shown to restore muscle function in a Duchenne muscular dystrophy mouse model. In this study, anti-RANKL therapy was evaluated in a more severe mouse model, specifically 4-week-old male dy2J/dy2J mice, which recapitulate key CMD1A features. A 1-month anti-RANKL treatment significantly improved specific muscle strength, increased myofiber cross-sectional area, and reduced edema and immune cell infiltration. It also enhanced bone strength and microarchitecture. However, absolute muscle force and global motor performance remained unchanged. Overall, anti-RANKL treatment improved muscle intrinsic properties and bone parameters in dy2J/dy2J dystrophic mice, but these improvements were insufficient to enhance absolute muscle force or global motor performance.
2026-02-24 | Evaluation of Readthrough Efficiency of Negamycin Derivatives against Nonsense Mutations in Muscular Dystrophy Genes.
Recently, "readthrough compounds" have attracted attention as a promising approach to treat human hereditary diseases caused by nonsense mutations. These compounds enable ribosomes to bypass a premature termination codon (PTC) introduced into mRNA by a nonsense mutation, thereby restoring the expression of full-length functional proteins. We performed a structure-activity relationship study focusing on (+)-negamycin, a known readthrough compound, and identified potent derivatives, TCP-304 and TCP-306, featuring a cyclopropane moiety. In this study, we investigated how the nature of PTCs and their surrounding nucleotide sequences influence the readthrough activity of these negamycin derivatives, using nonsense mutation sequences derived from Duchenne muscular dystrophy and congenital muscular dystrophy genes. In cell-based reporter assay systems, TCP-306 exhibited potent readthrough efficiency against several nonsense mutation sequences containing the TGA-A. Moreover, its sequence preference differed from that of the aminoglycoside G418, a representative readthrough compound that preferentially induces readthrough at TGA-C sequences, suggesting that TCP-306 may serve as an alternative therapeutic option for muscular dystrophies associated with TGA-A nonsense mutations. Overall, this study provides valuable insights for the development of readthrough drugs for hereditary diseases such as muscular dystrophy caused by nonsense mutations.
2025-11-20 | Structural basis of Nuclear Factor 1-X DNA recognition provides prototypic insight into the NFI family.
Nuclear Factor I (NFI) proteins are involved in adenovirus DNA replication and regulate gene transcription, stem cell proliferation, and differentiation. They play key roles in development, cancer, and congenital disorders. Within the NFI family, NFI-X is critical for neural stem cell biology, hematopoiesis, muscle development, muscular dystrophies, and oncogenesis. Here, we present the structural characterization of the NFI transcription factor NFI-X, both alone and bound to its consensus palindromic DNA site. Our analyses reveal a MH1-like fold within NFI-X DNA-binding domain (DBD) and identify crucial structural determinants for activity, such as a Zn²⁺ binding site, dimeric assembly, and DNA-binding specificity. Given the ~85% sequence identity within the NFI DBDs, our structural data are prototypic for the entire family, a NFI Rosetta Stone that allows decoding a wealth of biochemical and functional data and provides a precise target for drug design in a wider disease context.
2025-08-30 | Integrative Approaches to Myopathies and Muscular Dystrophies: Molecular Mechanisms, Diagnostics, and Future Therapies.
Myopathies and muscular dystrophies are a diverse group of rare or ultra-rare diseases that significantly impact patients' quality of life and pose major challenges for diagnosis and treatment. Despite their heterogeneity, many share common molecular mechanisms, particularly involving sarcomeric dysfunction, impaired autophagy, and disrupted gene expression. This review explores the genetic and pathophysiological foundations of major myopathy subtypes, including cardiomyopathies, metabolic and mitochondrial myopathies, congenital and distal myopathies, myofibrillar myopathies, inflammatory myopathies, and muscular dystrophies. Special emphasis is placed on the role of autophagy dysregulation in disease progression, as well as its therapeutic potential. We discuss emerging diagnostic approaches, such as whole-exome sequencing, advanced imaging, and muscle biopsy, alongside therapeutic strategies, including physiotherapy, supplementation, autophagy modulators, and gene therapies. Gene therapy methods, such as adeno-associated virus (AAV) vectors, CRISPR-Cas9, and antisense oligonucleotide, are evaluated for their promise and limitations. The review also highlights the potential of drug repurposing and artificial intelligence tools in advancing diagnostics and personalized treatment. By identifying shared molecular targets, particularly in autophagy and proteostasis networks, we propose unified therapeutic strategies across multiple myopathy subtypes. Finally, we discuss international research collaborations and rare disease programs that are driving innovation in this evolving field.
gene therapies
2026-08-20 | Advanced iPSC-based modeling of LMNA-related congenital muscular dystrophy enables development of genetic therapies for muscle laminopathies.
LMNA-related congenital muscular dystrophy (L-CMD) is one of the most severe laminopathies, which are incurable diseases primarily caused by pathogenic LMNA variants. LMNA encodes Lamin A/C, key components of the nuclear lamina, which provides structural stability to the nucleus while regulating chromatin organization and gene expression. L-CMD research is hindered by a lack of humanized, tissue-specific models that accurately recapitulate disease phenotypes. We previously reported nuclear shape abnormalities and Lamin mislocalization in LMNA-mutant induced pluripotent stem cell (iPSC)-derived skeletal muscle cells. Here, we expand the selection of L-CMD iPSCs, validate disease-associated readouts using a transgene-free differentiation protocol and assess gene editing strategies using 2D and 3D cultures. Results showed no overt defects in developmental myogenesis but recapitulated pathological nuclear shape abnormalities in monolayer cultures and engineered muscles, nuclear envelope protein mislocalization, and transcriptomic alterations across multiple pathogenic LMNA variants. We then used our platform to assess outcomes of LMNA gene editing. CRISPR-based exon-removal generated detectable RNA and protein Lamin A/C species, without normalization of nuclear morphology or transcriptomic profile. Conversely, precise editing of the same variant corrected nuclear morphometrics, alongside normalization of the pro-inflammatory transcriptomic signature, providing an advanced, humanized platform for translational research and precision medicine in laminopathies.
2026-08-04 | Adenine base editing correction of LMNA c.745C>T (p.R249W) in congenital muscular dystrophy myoblasts improves cellular phenotype while revealing deleterious p.L248P bystander effects
ABSTRACT Background LMNA -related congenital muscular dystrophy (L-CMD) is a rare, life-threatening genetic disorder caused by point mutations in the LMNA gene, for which no effective treatment currently exists. It is characterized by early-onset muscle weakness, dropped-head syndrome, hypotonia, cardiac complications, and restrictive lung disease, frequently leading to premature death. The LMNA c.745C>T (p.R249W) mutation is the most prevalent amongst L-CMD patients. Given its monogenic nature, L-CMD represents a compelling candidate for gene therapy approaches. Results In this study, we investigated the therapeutic potential of adenine base editing (ABE) to correct the pathogenic LMNA c.745C>T (p.R249W) mutation in human myoblasts. We evaluated multiple ABE variants and single-guide RNAs (sgRNAs), identifying optimal combinations that achieved efficient and specific correction of the mutant allele. However, we found that editing can also introduce an adjacent bystander mutation, c.743T>C (p.L248P). To determine the functional consequences of base editing, we established clonal cell lines reverted to wild type or harboring the p.L248P variant. Whereas wild-type edited cells showed a clear correction for all the studied parameters that were abnormal in R249W myoblasts, we found that L248P cells show nuclear abnormalities resembling those of R249W mutant cells, and their cellular function is partially compromised. These results demonstrate that ABE can effectively target the LMNA c.745C>T mutation but also reveal the significant impact of bystander edits on cellular physiology. Conclusions Our findings provide proof-of-concept for the application of base editing as a therapeutic strategy for L-CMD, while underscoring the necessity of precise editing technologies to ensure both efficacy and safety in future clinical translation.
2026-07-31 | Pediatric Ocular Abnormalities: A Pictorial Review of Genetic, Metabolic, and Syndromic Associations. Part 1: Abnormalities of the Globe and Lens
SUMMARY:
This 2-part pictorial review illustrates the spectrum of ocular abnormalities in pediatric imaging and highlights their diagnostic and prognostic implications. Part 1 focuses on globe and lens abnormalities, including the microphthalmos-anophthalmos-coloboma (MAC) complex, macrophthalmos, congenital cataracts, and lens dislocation. Part 2 covers posterior segment and optic pathway abnormalities, ranging from persistent fetal vasculature to optic nerve pathologies. Selected cases demonstrate key associated brain and spine imaging features, syndromic associations, and prognostic significance, showing how orbital imaging can guide targeted genetic testing, improve diagnostic accuracy, and differentiate overlapping conditions. By systematically evaluating the orbits on pediatric brain MRI, radiologists can identify genetic disorders and syndromes early, support clinical and genetic assessment, and improve patient care.
Abbreviations
CHARGE: coloboma of the eye, heart defects, atresia of the choanae, retardation of growth and/or development, genital and/or urinary abnormalities, and ear abnormalities and deafness CIMDAG: cerebellar hypoplasia and cataracts, intellectual disability, congenital microcephaly, dystonia and dyserythropoietic anemia, and growth retardation CS: Cockayne syndrome COACH syndrome: cerebellar vermis hypoplasia, oligophrenia, ataxia, coloboma, hepatic fibrosis ECCL: encephalocraniocutaneous lipomatosis FCMD: Fukuyama congenital muscular dystrophy JS: Joubert syndrome MAC: microphthalmos-anophthalmos-coloboma MEB: muscle-eye-brain disease MGDA: morning glory disc anomaly OAVS: oculo-auriculo-vertebral spectrum OCCS: oculocerebrocutaneous syndrome PBS: Poretti-Boltshauser syndrome TORCH: toxoplasmosis, other agents (such as HIV, syphilis, and Zika), rubella, cytomegalovirus, and herpes simplex virus WMS: Weill-Marchesani syndrome WWS: Walker-Warburg syndrome
2026-07-30 | Triple-AAV intein-mediated gene therapy ameliorates dystrophic phenotype in MDC1A mice.
Several therapies using adeno-associated viruses (AAVs) as a gene delivery tool have received marketing approval in the past. However, potential applications of AAVs are limited by their restricted gene packaging capacities (<4.7 kb). Many monogenic diseases are caused by large complex genes with hundreds of pathogenic variants that exceed AAV capacity. Merosin-deficient congenital muscular dystrophy type 1A is a severe monogenic recessive disease caused by the absence of functional copies of the LAMA2 gene. To date, no treatment options are available, with the most promising approach being gene replacement therapy to provide a functional copy. The LAMA2 coding sequence, spanning 9.3 kb, encodes laminin-α2, a subunit of the trimeric protein Laminin-211 found in the basement membrane of skeletal muscle cells and Schwann cells. Efforts have been focused on gene or protein replacement along with basement membrane engineering. Here, we exploit the ability of inteins to reconstitute full-length protein in a scarless manner. Using a combination of three AAVs, each encoding one fragment of the laminin-α2 protein flanked by a short split intein, resulted in the complete reconstitution of Laminin-α2 and an improvement of the histopathological features of the dy2j dystrophic mouse model.
2026-06-15 | Preclinical efficacy of a gene therapy for CHKB-mediated muscular dystrophy.
Loss-of-function variants of the CHKB gene cause an autosomal recessive disease described as an early onset congenital megaconial (large peripheral mitochondria) muscular dystrophy. CHKB encodes choline kinase β, the first enzyme in the biochemical pathway for synthesis of the major membrane phospholipid phosphatidylcholine. Chkb -/- mice recapitulate the human disease with affected skeletal muscle displaying a decrease in strength, myofiber atrophy, megaconial mitochondria, fat accumulation within muscle cells, and an increase in muscle injury. Here, we assessed the therapeutic potential of an AAV therapy for the treatment of CHKB-mediated muscular dystrophy. Chkb -/- mice were injected once suborbitally with three different doses of recombinant AAV9 (rAAV9) encoding human CHKB under control of a constitutive and ubiquitous promoter (AAV9-CHKB). The AAV9-CHKB-treated mice were biochemically and phenotypically indistinguishable from the wild type mice. In the Chkb -/- mouse model, all doses resulted in expression of the CHKB protein and restored choline kinase β enzyme activity, body and muscle weight, and normal muscle cell physiology, and they prevented lipid metabolism imbalance and increased the capacity to walk. These findings point to AAV9-mediated gene therapy as a potential treatment for CHKB-mediated disease.
proteins
2026-02-04 | Dual AAV gene therapy using laminin-linking proteins ameliorates muscle and nerve defects in LAMA2-related muscular dystrophy.
Adeno-associated virus (AAV)-mediated gene replacement holds promise for treating genetic diseases but faces challenges due to the limited packaging capacity and potential immune responses to transgene products, especially in patients lacking endogenous protein. LAMA2-related muscular dystrophy (LAMA2 MD), a severe congenital disorder caused by loss of laminin-α2, presents both hurdles: the LAMA2 gene exceeds AAV capacity, and severely affected patients do not produce the native protein. Here, we developed an AAV-based therapy using two engineered linker proteins derived from endogenously expressed components. These linker proteins restore laminin receptor binding and polymerization, enabling reassembly of a functional basement membrane. Dual AAV delivery of the linkers in a severe LAMA2 MD mouse model resulted in robust expression and significant improvements in muscle histology and function. Employing myotropic capsids enabled therapeutic efficacy at lower vector doses. However, muscle-specific targeting unmasked a LAMA2-related peripheral neuropathy. To address this, we expressed one linker under a muscle-specific promoter and the other under a ubiquitous promoter, delivered via AAV9 or AAV8. This approach achieved near-complete phenotypic restoration when administered neonatally and provided significant benefit when given at progressed disease stages. Our strategy offers a mutation-independent, size-compatible, and potentially immune-tolerable treatment for LAMA2 MD with broad clinical potential.
2025-10-21 | Spatial proteomics reveals recombinant human laminin-111 restores adhesion signaling to laminin-α2-deficient muscle.
Laminin-α2-related congenital muscular dystrophy (LAMA2-CMD) is a severe neuromuscular disorder caused by mutations in the LAMA2 gene, leading to loss of heterotrimers laminin-211/221, key components of the skeletal muscle extracellular matrix. Their absence disrupts adhesion between the cytoskeleton and extracellular matrix, resulting in progressive muscle wasting. Laminin-211/221 interacts with adhesion complexes such as the dystrophin/utrophin glycoprotein complex and α7β1-integrin. However, the regulatory mechanisms of these laminin-binding complexes and the broader role of laminin's influence on the formation of the macromolecular network in skeletal muscle remain unclear. We previously demonstrated that delivering mouse laminin-111 to the dyW-/- mouse model of LAMA2-CMD prevented disease progression, improved strength, and extended survival. We hypothesize that laminin-111, the embryonic laminin isoform, restores key adhesion-signaling networks. Using spatial proteomics on patient and mouse muscle, we identified loss of essential signaling components: heat shock proteins 27 and 70, c-Jun N-terminal kinase, and glucose transporter 1 in laminin-α2-deficient muscle. Treatment with recombinant human laminin-111 (rhLAM-111) restored protein localization, reduced ROS, and promoted glycolytic, prosurvival signaling. These findings highlight laminin's role in maintaining muscle homeostasis and metabolism and support the therapeutic potential of rhLAM-111 for treating LAMA2-CMD by restoring adhesion and intracellular signaling in dystrophic muscle.
2024-05-24 | Prophylactic immunoglobulin therapy for pediatric congenital myotonic dystrophy.
Congenital Myotonic Dystrophy (CMD) is an autosomal dominant hereditary disease caused by mutations in the dystrophia myotonica protein kinase gene. Patients with CMD often exhibit low immunoglobulin (Ig) G levels. While Ig replacement therapy for low IgG levels has been reported in several adult cases, there have been no reports on pediatric patients. This study presents a first pediatric case where Ig replacement therapy effectively eliminated susceptibility to infections. The CMD patient, a 1-year-old Japanese female with a history of premature birth and necrotizing enterocolitis, developed recurrent severe bacterial infections due to hypogammaglobulinemia. Intravenous immunoglobulin (IVIG) (600 mg/kg/month) was administered but failed to maintain sufficient serum trough IgG levels. The dosage was increased to 2 g/kg/month, and later, the treatment shifted to subcutaneous immunoglobulin (SCIG), resulting in a stable serum trough IgG level above 700 mg/dL for one year. The cause of hypogammaglobulinemia in CMD patients remains unclear, but potential mechanisms, including IgG-mediated hypercatabolism by alterations in the neonatal Fc receptor, have been considered. Genetic testing ruled out common variable immunodeficiency, and other potential causes were excluded. The study suggests that higher doses of IVIG or SCIG can effectively prevent severe infections associated with CMD-induced hypogammaglobulinemia in children. This case report sheds light on the efficacy of immunoglobulin therapy in pediatric congenital myotonic dystrophy (CMD). We anticipate that our findings will have a positive impact on clinical practice by providing insights into the prevention of severe infections associated with CMD-induced hypogammaglobulinemia. This research is of great interest to the readers of the journal as it addresses an unmet need in pediatric CMD management by providing a strategy for successful immunoglobulin therapy for the treatment of pediatric CMD.
2023-08-22 | PAX7, a Key for Myogenesis Modulation in Muscular Dystrophies through Multiple Signaling Pathways: A Systematic Review
Muscular dystrophy is a heterogenous group of hereditary muscle disorders caused by mutations in the genes responsible for muscle development, and is generally defined by a disastrous progression of muscle wasting and massive loss in muscle regeneration. Pax7 is closely associated with myogenesis, which is governed by various signaling pathways throughout a lifetime and is frequently used as an indicator in muscle research. In this review, an extensive literature search adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed to identify research that examined signaling pathways in living models, while quantifying Pax7 expression in myogenesis. A total of 247 articles were retrieved from the Web of Science (WoS), PubMed and Scopus databases and were thoroughly examined and evaluated, resulting in 19 articles which met the inclusion criteria. Admittedly, we were only able to discuss the quantification of Pax7 carried out in research affecting various type of genes and signaling pathways, rather than the expression of Pax7 itself, due to the massive differences in approach, factor molecules and signaling pathways analyzed across the research. However, we highlighted the thorough evidence for the alteration of the muscle stem cell precursor Pax7 in multiple signaling pathways described in different living models, with an emphasis on the novel approach that could be taken in manipulating Pax7 expression itself in dystrophic muscle, towards the discovery of an effective treatment for muscular dystrophy. Therefore, we believe that this could be applied to the potential gap in muscle research that could be filled by tuning the well-established marker expression to improve dystrophic muscle.
2022-10-31 | The extracellular matrix differentially directs myoblast motility in distinct forms of muscular dystrophy
ABSTRACT Extracellular matrix (ECM) pathologic remodeling underlies many fibrotic disorders, including muscular dystrophy. Tissue decellularization removes cellular components while leaving behind ECM components. We generated “on-slide” decellularized tissue slices from genetically distinct dystrophic mouse models. The ECM of dystrophin-and sarcoglycan-deficient muscles had marked thrombospondin 4 deposition, while dysferlin-deficient muscle had excess decorin. Annexins A2 and A6 were present on all dystrophic decellularized ECMs, but annexin matrix deposition was excessive in dysferlin-deficient muscular dystrophy. Adeno-associated viral expression of annexin A6 specifically in muscle resulted in annexin A6 deposition throughout the ECM, indicating muscle as a source of this ECM protein. C2C12 myoblasts seeded onto decellularized matrices displayed differential myoblast mobility. Dystrophin-deficient decellularized matrices inhibited myoblast mobility while dysferlin-deficient decellularized matrices enhanced myoblast movement. Myoblasts treated with recombinant annexin A6 increased mobillity similar to that seen on dysferlin-deficient decellularized matrix. These findings demonstrate specific fibrotic signatures elicit effects on myoblast activity. TEASER Fibrosis in muscular dystrophy has differential effects on myoblasts HIGHLIGHTS Spatial architecture and composition of the ECM differ across genetically distinct forms of muscular dystrophy, especially with respect to Annexin A6 protein deposition Matrix from dystrophin-mediated muscular dystrophy inhibits myoblast movement Matrix from dysferlin-deficient muscular dystrophy promotes myoblast motility Annexin A6 was sufficient to enhance myoblast motility
oligonucleotides
2026-09-30 | Gapmer and Mixmer Antisense Oligonucleotides to Selectively Suppress the Mutant Allele in COL6A Genes in Dominant Ullrich Congenital Muscular Dystrophy.
Allele-specific gene silencing with antisense oligonucleotides (ASOs) or small interfering RNA (siRNA) is a promising strategy for disorders driven by dominant gain-of-function effects. We here present two antisense approaches, gapmer and mixmer ASOs, to mitigate the dominant-negative mechanism underlying Ullrich congenital muscular dystrophy (UCMD) caused by recurrent COL6A3 mutations. We outline the details of methods that our lab has used. The methods comprise the rational ASO design (classical gapmers and mixmers to enhance allele selectivity), in vitro evaluation of allele-specific mRNA knockdown, and protein-level functional assessment. Patient-derived dermal fibroblasts harboring COL6A3 c.6210+1G>A or c.6135_6152del were used as cellular models.
2025-09-07 | Fukuyama congenital muscular dystrophy: Clinical features and therapeutic advances.
Fukuyama congenital muscular dystrophy (FCMD, a severe form of muscular dystrophy characterized by brain structural anomalies and ocular complications due to neuronal migration disorders, is notably limited mainly to Japan. Ninety percent of patients are unable to walk throughout their lives and die before the age of 20 due to respiratory failure and cardiomyopathy. At present, there is no cure. The founder variant, a 3-kb insertion in FKTN, is an SVA (SINE-VNTR-Alu) retrotransposon, and FCMD is a splicing disorder attributable the exon trapping function of this retrotransposon. A splicing modulation therapy targeting exon-trapping based on using antisense nucleic acids to block abnormal splicing is under development, and clinical trials have begun. Additionally, it was clarified that the gene product of FKTN is a glycosyltransferase that transfers ribitol-5-phosphate from cytidine diphosphate ribitol, a precursor for the synthesis of the O-mannosyl glycans of α-dystroglycan, a cell membrane component. This finding raises hopes for a prodrug therapy. Though patient numbers were small, previous clinical studies suggested that steroids are effective in FCMD. Thus, phase II clinical trials are underway with the aim of obtaining insurance approval. This review provides an overview of the clinical course and current status of treatments being developed for FCMD.
2025-08-27 | Muscle transcriptome profiling reveals novel molecular pathways and biomarkers in laminin-α2 deficient patients
Merosin-deficient congenital muscular dystrophy (LAMA2-RD) is caused by LAMA2 gene mutations, coding for laminin-211 (merosin) α2 subunit. LAMA2 mutations leading to complete laminin-211 absence result in an invariably severe clinical phenotype, with profound muscle weakness and respiratory insufficiency. Milder phenotypes are often associated with mutations allowing the production of a partially functional protein. While several dysregulated genes/pathways linked to LAMA2-RD muscle loss are known, an in-depth characterization of LAMA2-RD muscle gene expression profile in patients with mutations differentially affecting LAMA2 expression is lacking. We generated muscle transcriptomic data from patients with either complete or partial laminin-211 deficiency, and identified pathways linked to the most dysregulated processes. Genes related to fibrosis, inflammation and metabolism were similarly expressed in both patient cohorts. However, a subset of novel pro-fibrotic and pro-inflammatory genes were exclusively expressed in patients (and mice) completely lacking laminin-211, indicating aspects exacerbated in this cohort. Our work characterizes the main contributors of human LAMA2-RD pathology, providing insight into molecular pathways that could be used as disease biomarkers or as targets for therapeutic approaches.
2025-07-28 | An Overview of Recent Advances and Clinical Applications of Exon Skipping and Splice Modulation for Muscular Dystrophy and Various Genetic Diseases.
Exon skipping and splice modulation using synthetic antisense oligonucleotides (AONs) are therapeutic approaches to delay or arrest the progression of genetic diseases. AON-mediated exon skipping modifies pre-mRNA splicing to correct the reading frame of genes responsible for disease and modulate a protein structure, providing therapeutic benefits. Studied for over two decades, exon skipping AONs have received conditional marketing authorization for Duchenne muscular dystrophy (DMD). The US Food and Drug Administration (FDA) has granted accelerated approval for four AONs to skip a single DMD exon for treating patients with DMD: eteplirsen for exon 51 skipping, golodirsen and viltolarsen for exon 53 skipping, and casimersen for exon 45 skipping. Various preclinical and clinical trials are underway with AONs targeting other exons and ones loading bioconjugates, such as cell-penetrating peptides and antibodies to enhance the exon skipping ability. Besides AONs targeting pre-mRNA, genomic DNA target exon skipping using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology, which holds promise in current preclinical trials for DMD. In hopes of achieving clinical success parallel to DMD, exon skipping and splice modulation are studied in other muscular dystrophies, such as Fukuyama congenital muscular dystrophy (FCMD), dysferlinopathy including limb-girdle muscular dystrophy type 2B (LGMD2B), Miyoshi myopathy (MM), and distal anterior compartment myopathy (DMAT), myotonic dystrophy, and merosin-deficient congenital muscular dystrophy type 1A (MDC1A). Splice-modulating AONs have also been extensively tested in other inherited diseases, such as Usher syndrome, dystrophic epidermolysis bullosa (DEB), fibrodysplasia ossificans progressiva (FOP), and allergic diseases. This chapter will introduce the developmental status of exon skipping and splice-modulating therapies for genetic diseases.
2025-07-28 | Exon-Skipping Using Antisense Oligonucleotides for Laminin-Alpha2-Deficient Muscular Dystrophy.
Phosphorodiamidate morpholino oligomer (PMO)-mediated exon-skipping is among the more promising approaches available for the treatment of several neuromuscular disorders, including Duchenne muscular dystrophy. The main weakness of this treatment arises from the low efficiency and sporadic nature of the delivery of neutrally charged PMOs into muscle fibres, the mechanism of which is unknown. Recently, using wild-type and dystrophic mdx52 mice, we showed that muscle fibres took up PMOs more efficiently during myotube formation. Interestingly, we detected PMO mainly in embryonic myosin heavy chain-positive regenerating fibres through in situ hybridisation. Next, we tested the therapeutic potential of PMOs in laminin-alpha2 (laminin-α2) chain-null dy3K/dy3K mice, a model of merosin-deficient congenital muscular dystrophy 1A (MDC1A or LAMA2-related muscular dystrophy: LAMA2-MD) with active muscle regeneration. We confirmed the recovery of the laminin-α2 chain following the skipping of the mutated exon 4 in dy3K/dy3K mice, which prolonged the lifespan of the animals slightly. These findings support the theory that PMO entry into fibres is dependent on the developmental stage in myogenesis rather than on dystrophin-deficient muscle membranes, and recommend a platform for the future development of PMO-mediated therapies for a variety of muscular disorders, such as LAMA2-MD, that involve active muscle regeneration. Herein, we describe the methods for PMO transfection/injection and the evaluation of the efficacy of exon-skipping in the laminin-α2-deficient dy3K/dy3K mouse model both in vitro and in vivo.
other
2026-07-02 | Muscle-Specific Kinase Signaling and Its Therapeutic Potential.
The function of the neuromuscular junction (NMJ) is compromised in many neuromuscular diseases (NMDs) such as autoimmune or congenital myasthenia gravis (MG), amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), and muscular dystrophies. The NMJ contains muscle-specific kinase (MuSK), which is a critical regulator of NMJ integrity and function. Activating the MuSK signaling cascade may have therapeutic potential in several of these NMDs that are characterized by impaired neuromuscular communication. The MuSK signaling cascade consists of different components and can be activated with interventions at different levels. In the past years, different therapeutic strategies using an engineered recombinant agrin comprised of the C-terminal fragment of the protein (mini-agrin), gene therapy of key proteins in this pathway, agonist MuSK antibodies, and SRC homology 2 domain-containing phosphotyrosine phosphatase 2 (SHP2) inhibitors have been further developed for this purpose. Each of these strategies engages distinct signaling components: mini-agrin, both as recombinant protein and gene therapy, enhances agrin-Lrp4-MuSK interaction; Dok7 gene therapy amplifies MuSK phosphorylation; Lrp4 gene therapy enhances agrin responsiveness; MuSK agonist antibodies bypass upstream defects and promote downstream signaling; SHP2 inhibitors prolong the duration of active MuSK signaling. These therapeutic strategies have ameliorated NMJ integrity and function in several preclinical models of MG, motor neuron diseases, and muscular dystrophies. In this review, we highlight MuSK signaling as a possible therapeutic target, describe the therapeutic efficacy of intervention in MuSK signaling in different NMDs, and present an outlook on future clinical development.
2025-09-29 | [iPS cell-based therapy for muscular disorders].
Induced pluripotent stem cells (iPSCs) have been used in research for the development of treatments for various intractable diseases due to their unlimited proliferative and multipotent potential. We are aiming to develop novel therapies for intractable muscular diseases using iPS cells by two approaches i.e. cell therapy and drug screening. In this presentation, I focus on the cell therapy research. We have developed a differentiation induction method that mimics the developmental stages and have succeeded in inducing skeletal muscle stem cells that are applicable to cell transplantation therapy. We have found that cell transplantation into Duchenne muscular dystrophy (DMD) model mice is effective in regenerating more than 10% of dystrophin-positive fibers. In addition, some of the cells have been engrafted as satellite cells in vivo, and it is expected that the therapeutic effect will continue for a long period of time. As for the efficacy to the motor function, we have recently revealed that the regeneration of dystrophin positive myofibers in DMD model mice mainly ameliorates muscle fatigue tolerance rather than maximal contraction force in vivo. We have also developed a differentiation method to induce mesenchymal stromal cells (MSCs) from iPSCs. Transplantation of iPSC-derived MSCs (iMSCs) into Ullrich congenital muscular dystrophy (UCMD) model mice enabled the restoration of collagen type VI which resulted in enhancement of muscle regeneration. Interestingly, somatic MSCs such as bone marrow-derived MSC or adipose-derived MSC do not have therapeutic effect even they can also restore collagen type VI by the transplantation. We have recently found one of the candidates which is responsible for the muscle regeneration and is specifically expressed in the iMSCs.
2025-09-19 | Antxr2-mediated fine-tuning of Collagen VI ensures skeletal muscle function
ABSTRACT Tissue function relies on the extracellular matrix (ECM) that surrounds cells, providing structural and biochemical support. The complex ECM composition depends on an adequately tuned balance between the deposition and degradation of each of its components. Disequilibrium may cause disease, as observed for Collagen VI (COL6), for which mutations lead to muscular dystrophy. Here, we investigated the role of Anthrax Toxin Receptor 2 (ANTXR2/CMG2), a receptor that controls the turnover of COL6, in skeletal muscle. We show that ANTXR2 is mostly expressed by fibro-adipogenic precursors and that its deficiency in ANTXR2 null ( Antxr2 -/- ) mice leads to a premature and irregular COL6 accumulation in intramuscular connective tissue. This results in tissue stiffening and gradual, non-functional muscle hypertrophy, marked by impaired locomotion and myopathic signs. Our findings further indicate that COL6 accretion drives these alterations, as revealed by Antxr2 -/- ::Col6a1 -/- double knockout mice, highlighting the essential role of ANTXR2-mediated COL6 remodeling in maintaining ECM homeostasis and muscle functionality. SIGNIFICANCE STATEMENT Remodelling of the extracellular matrix (ECM) was long thought to rely almost exclusively on extracellular proteases. Increasing evidence, however, indicates that some ECM components may undergo intracellular degradation following receptor-mediated endocytosis, as we have found for Collagen VI (COL6). Here, we identify the COL6 receptor ANTXR2 as a critical regulator of ECM turnover in skeletal muscle.. When ANTXR2 is absent, COL6 builds up, followed by the accumulation of fibrillar collagens, without changes in gene expression. These alterations in muscle ECM lead to increased stiffness, myofiber defects and impaired locomotor activity. Our findings establish ANTXR2 as a key regulator in ECM remodelling, offering new insights into potential treatments for conditions associated with defective ECM remodeling, such as aging and congenital muscular dystrophies.
2025-07-08 | Anti-myogenic and profibrotic effect of serum from patients affected by muscular laminopathies.
Emery-Dreifuss Muscular Dystrophy type 2 (EDMD2) and LMNA-related congenital muscular dystrophy (L-CMD) are caused by mutations in LMNA gene. Both pathologies are characterized by joint contractures, muscle weakness and wasting and cardiac involvement. In the last few years, circulating factors have been proposed to play a critical role in the pathogenesis of these diseases. Based on this consideration, we studied the effect of laminopathic serum on the myogenic differentiation in healthy human myoblasts in culture. We observed impaired myogenesis and increased fibrosis in myoblast cultures conditioned with laminopathic serum and a dramatic increase in the level of profibrotic and proinflammatory cytokines in the cell culture supernatants. These results strongly support the pathogenic role of circulating factors in muscular laminopathies and pave the way to a possible therapeutic strategy.
2025-06-08 | Breakthrough in Functional Muscle Regeneration: Biomimetic Collagen Scaffold Restores Abdominal Wall Defects in a VML-rabbit Model
Abstract Functional regeneration of volumetric muscle loss (VML) remains a significant challenge in the field of regenerative medicine. We have developed a novel biomimetic scaffold (0.4 mm thick hernia patch) derived from soluble collagen. This biomimetic scaffold exhibits exceptional strength, low immunogenicity, and structurally mimics the natural muscle fiber arrangement. The scaffold is utilized to repair a VML rabbit model (30 × 30 mm defect in abdominal wall) using nylon sutures for connection. It was observed that the VML site was gradually covered by regenerated tissue, which consisted of 2-3 mm thick functional muscle. By 32 weeks post-surgery, the newly formed muscle tissue had covered the majority of the VML area, as evidenced by morphological observations and histological evaluations. Approximately 24 weeks after surgery, the scaffold underwent complete degradation. This degradation exhibited a strong correlation with muscle regeneration. Furthermore, it was observed that the nylon sutures gradually migrated towards the VML center as muscle regeneration progressed, and nylon sutures exhibited an adverse impact on muscle regeneration.. The study did not employ exogenous cells or growth factors. However, the collagen scaffold effectively stimulated endogenous muscle regeneration. In contrast to the previous limited partial recovery or fibrotic scar healing, the collagen scaffold successfully induced genuine structural and functional muscle regeneration. The 0.4 mm thick scaffold (hernia patch) exhibits a different structure from the 2-3 mm thick natural abdominal muscle wall. This suggests that a simple scaffold can regenerate functional tissue with a complex structure. This research represents the first successful functional regeneration of VML in clinically relevant animal models through the utilization of artificial materials. This technology possesses transformative potential in the treatment of muscle defects arising from trauma, tumor resection, hernia, or congenital anomalies. Furthermore, it holds substantial medical potentials in addressing neuromuscular diseases, such as Duchenne muscular dystrophy (DMD), amyotrophic lateral sclerosis (ALS), and spinal muscular atrophy (SMA), by collaborating with advanced technologies including CRISPR-Cas9, adeno-associated virus (AAV) gene therapy, and stem cell technology.
small molecules
2026-07-27 | Cortical organoids from congenital DM1 PSCs reveal MBNL-dependent corticogenesis defects and enable preclinical testing of therapeutic compounds
ABSTRACT Myotonic dystrophy type 1 (DM1) is caused by an expansion of a CTG repeat in the 3′ untranslated region of the DMPK gene, leading to accumulation of toxic CUG-repeat RNAs, sequestration of MBNL proteins and widespread splicing dysregulation. Congenital DM1 (CDM), the most severe form of the disease, is associated with profound muscular and neurodevelopmental defects, yet the mechanisms underlying early human brain involvement remain poorly understood. Here, we generated cortical organoids from patient-derived pluripotent stem cells carrying >1000 CTG repeats, an expansion typically associated with CDM, to model early human neurodevelopment. DM1 molecular and cellular hallmarks were detected at early developmental stages, including nuclear DMPK RNA foci in neural progenitor cells and reduced proliferative capacity. As organoids matured, CDM cultures displayed altered cortical composition, with reduced CTIP2⁺ and SATB2⁺ neuronal populations and increased NFIA⁺/GFAP⁺ glial cells. In parallel, 120-day-old organoids recapitulated splicing abnormalities previously identified in DM1 patient brain tissue. To assess the contribution of MBNL dysfunction, we analyzed cortical organoids derived from MBNL2 and MBNL1/2/3 knockout induced pluripotent stem cells, which reproduced key neurodevelopmental phenotypes observed in CDM organoids, supporting a central role for MBNL loss of function in impaired corticogenesis. Finally, we evaluated the translational relevance of this model using tideglusib and erythromycin, two compounds currently under clinical evaluation in DM1 patients. Both treatments reduced DMPK RNA foci and restored proliferation defects in SOX2⁺ neural progenitors. Together, these findings establish cortical organoids as a robust human model of CDM-associated neurodevelopmental defects, uncover MBNL-dependent mechanisms underlying early corticogenesis impairment and demonstrate the utility of this platform for translational therapeutic discovery in DM1.
2026-05-13 | Anti-Receptor Activator of Nuclear Factor-κB Ligand Improves Muscle Dysfunction and Strengthens Bone in Laminin-α2-Deficient dy2J/dy2J Dystrophic Mice.
Congenital muscular dystrophy type 1A (CMD1A) is a severe genetic neuromuscular disorder caused by mutations in the LAMA2 gene, which encodes the laminin-α2 subunit, an essential structural protein for maintaining muscle integrity during contraction. Affected children experience progressive muscle damage, hypotonia, delayed motor development, and respiratory tract insufficiency. CMD1A muscles undergo repeated cycles of degeneration and regeneration accompanied by chronic inflammation. Beyond its established role in bone remodeling, the receptor activator of nuclear factor-κB/receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin signaling axis has also been implicated in muscle pathophysiology. A 10-day treatment with full-length osteoprotegerin fused to an Fc fragment was previously shown to restore muscle function in a Duchenne muscular dystrophy mouse model. In this study, anti-RANKL therapy was evaluated in a more severe mouse model, specifically 4-week-old male dy2J/dy2J mice, which recapitulate key CMD1A features. A 1-month anti-RANKL treatment significantly improved specific muscle strength, increased myofiber cross-sectional area, and reduced edema and immune cell infiltration. It also enhanced bone strength and microarchitecture. However, absolute muscle force and global motor performance remained unchanged. Overall, anti-RANKL treatment improved muscle intrinsic properties and bone parameters in dy2J/dy2J dystrophic mice, but these improvements were insufficient to enhance absolute muscle force or global motor performance.
2026-02-24 | Evaluation of Readthrough Efficiency of Negamycin Derivatives against Nonsense Mutations in Muscular Dystrophy Genes.
Recently, "readthrough compounds" have attracted attention as a promising approach to treat human hereditary diseases caused by nonsense mutations. These compounds enable ribosomes to bypass a premature termination codon (PTC) introduced into mRNA by a nonsense mutation, thereby restoring the expression of full-length functional proteins. We performed a structure-activity relationship study focusing on (+)-negamycin, a known readthrough compound, and identified potent derivatives, TCP-304 and TCP-306, featuring a cyclopropane moiety. In this study, we investigated how the nature of PTCs and their surrounding nucleotide sequences influence the readthrough activity of these negamycin derivatives, using nonsense mutation sequences derived from Duchenne muscular dystrophy and congenital muscular dystrophy genes. In cell-based reporter assay systems, TCP-306 exhibited potent readthrough efficiency against several nonsense mutation sequences containing the TGA-A. Moreover, its sequence preference differed from that of the aminoglycoside G418, a representative readthrough compound that preferentially induces readthrough at TGA-C sequences, suggesting that TCP-306 may serve as an alternative therapeutic option for muscular dystrophies associated with TGA-A nonsense mutations. Overall, this study provides valuable insights for the development of readthrough drugs for hereditary diseases such as muscular dystrophy caused by nonsense mutations.
2025-11-20 | Structural basis of Nuclear Factor 1-X DNA recognition provides prototypic insight into the NFI family.
Nuclear Factor I (NFI) proteins are involved in adenovirus DNA replication and regulate gene transcription, stem cell proliferation, and differentiation. They play key roles in development, cancer, and congenital disorders. Within the NFI family, NFI-X is critical for neural stem cell biology, hematopoiesis, muscle development, muscular dystrophies, and oncogenesis. Here, we present the structural characterization of the NFI transcription factor NFI-X, both alone and bound to its consensus palindromic DNA site. Our analyses reveal a MH1-like fold within NFI-X DNA-binding domain (DBD) and identify crucial structural determinants for activity, such as a Zn²⁺ binding site, dimeric assembly, and DNA-binding specificity. Given the ~85% sequence identity within the NFI DBDs, our structural data are prototypic for the entire family, a NFI Rosetta Stone that allows decoding a wealth of biochemical and functional data and provides a precise target for drug design in a wider disease context.
2025-08-30 | Integrative Approaches to Myopathies and Muscular Dystrophies: Molecular Mechanisms, Diagnostics, and Future Therapies.
Myopathies and muscular dystrophies are a diverse group of rare or ultra-rare diseases that significantly impact patients' quality of life and pose major challenges for diagnosis and treatment. Despite their heterogeneity, many share common molecular mechanisms, particularly involving sarcomeric dysfunction, impaired autophagy, and disrupted gene expression. This review explores the genetic and pathophysiological foundations of major myopathy subtypes, including cardiomyopathies, metabolic and mitochondrial myopathies, congenital and distal myopathies, myofibrillar myopathies, inflammatory myopathies, and muscular dystrophies. Special emphasis is placed on the role of autophagy dysregulation in disease progression, as well as its therapeutic potential. We discuss emerging diagnostic approaches, such as whole-exome sequencing, advanced imaging, and muscle biopsy, alongside therapeutic strategies, including physiotherapy, supplementation, autophagy modulators, and gene therapies. Gene therapy methods, such as adeno-associated virus (AAV) vectors, CRISPR-Cas9, and antisense oligonucleotide, are evaluated for their promise and limitations. The review also highlights the potential of drug repurposing and artificial intelligence tools in advancing diagnostics and personalized treatment. By identifying shared molecular targets, particularly in autophagy and proteostasis networks, we propose unified therapeutic strategies across multiple myopathy subtypes. Finally, we discuss international research collaborations and rare disease programs that are driving innovation in this evolving field.
gene therapies
2026-08-20 | Advanced iPSC-based modeling of LMNA-related congenital muscular dystrophy enables development of genetic therapies for muscle laminopathies.
LMNA-related congenital muscular dystrophy (L-CMD) is one of the most severe laminopathies, which are incurable diseases primarily caused by pathogenic LMNA variants. LMNA encodes Lamin A/C, key components of the nuclear lamina, which provides structural stability to the nucleus while regulating chromatin organization and gene expression. L-CMD research is hindered by a lack of humanized, tissue-specific models that accurately recapitulate disease phenotypes. We previously reported nuclear shape abnormalities and Lamin mislocalization in LMNA-mutant induced pluripotent stem cell (iPSC)-derived skeletal muscle cells. Here, we expand the selection of L-CMD iPSCs, validate disease-associated readouts using a transgene-free differentiation protocol and assess gene editing strategies using 2D and 3D cultures. Results showed no overt defects in developmental myogenesis but recapitulated pathological nuclear shape abnormalities in monolayer cultures and engineered muscles, nuclear envelope protein mislocalization, and transcriptomic alterations across multiple pathogenic LMNA variants. We then used our platform to assess outcomes of LMNA gene editing. CRISPR-based exon-removal generated detectable RNA and protein Lamin A/C species, without normalization of nuclear morphology or transcriptomic profile. Conversely, precise editing of the same variant corrected nuclear morphometrics, alongside normalization of the pro-inflammatory transcriptomic signature, providing an advanced, humanized platform for translational research and precision medicine in laminopathies.
2026-08-04 | Adenine base editing correction of LMNA c.745C>T (p.R249W) in congenital muscular dystrophy myoblasts improves cellular phenotype while revealing deleterious p.L248P bystander effects
ABSTRACT Background LMNA -related congenital muscular dystrophy (L-CMD) is a rare, life-threatening genetic disorder caused by point mutations in the LMNA gene, for which no effective treatment currently exists. It is characterized by early-onset muscle weakness, dropped-head syndrome, hypotonia, cardiac complications, and restrictive lung disease, frequently leading to premature death. The LMNA c.745C>T (p.R249W) mutation is the most prevalent amongst L-CMD patients. Given its monogenic nature, L-CMD represents a compelling candidate for gene therapy approaches. Results In this study, we investigated the therapeutic potential of adenine base editing (ABE) to correct the pathogenic LMNA c.745C>T (p.R249W) mutation in human myoblasts. We evaluated multiple ABE variants and single-guide RNAs (sgRNAs), identifying optimal combinations that achieved efficient and specific correction of the mutant allele. However, we found that editing can also introduce an adjacent bystander mutation, c.743T>C (p.L248P). To determine the functional consequences of base editing, we established clonal cell lines reverted to wild type or harboring the p.L248P variant. Whereas wild-type edited cells showed a clear correction for all the studied parameters that were abnormal in R249W myoblasts, we found that L248P cells show nuclear abnormalities resembling those of R249W mutant cells, and their cellular function is partially compromised. These results demonstrate that ABE can effectively target the LMNA c.745C>T mutation but also reveal the significant impact of bystander edits on cellular physiology. Conclusions Our findings provide proof-of-concept for the application of base editing as a therapeutic strategy for L-CMD, while underscoring the necessity of precise editing technologies to ensure both efficacy and safety in future clinical translation.
2026-07-31 | Pediatric Ocular Abnormalities: A Pictorial Review of Genetic, Metabolic, and Syndromic Associations. Part 1: Abnormalities of the Globe and Lens
SUMMARY:
This 2-part pictorial review illustrates the spectrum of ocular abnormalities in pediatric imaging and highlights their diagnostic and prognostic implications. Part 1 focuses on globe and lens abnormalities, including the microphthalmos-anophthalmos-coloboma (MAC) complex, macrophthalmos, congenital cataracts, and lens dislocation. Part 2 covers posterior segment and optic pathway abnormalities, ranging from persistent fetal vasculature to optic nerve pathologies. Selected cases demonstrate key associated brain and spine imaging features, syndromic associations, and prognostic significance, showing how orbital imaging can guide targeted genetic testing, improve diagnostic accuracy, and differentiate overlapping conditions. By systematically evaluating the orbits on pediatric brain MRI, radiologists can identify genetic disorders and syndromes early, support clinical and genetic assessment, and improve patient care.
Abbreviations
CHARGE: coloboma of the eye, heart defects, atresia of the choanae, retardation of growth and/or development, genital and/or urinary abnormalities, and ear abnormalities and deafness CIMDAG: cerebellar hypoplasia and cataracts, intellectual disability, congenital microcephaly, dystonia and dyserythropoietic anemia, and growth retardation CS: Cockayne syndrome COACH syndrome: cerebellar vermis hypoplasia, oligophrenia, ataxia, coloboma, hepatic fibrosis ECCL: encephalocraniocutaneous lipomatosis FCMD: Fukuyama congenital muscular dystrophy JS: Joubert syndrome MAC: microphthalmos-anophthalmos-coloboma MEB: muscle-eye-brain disease MGDA: morning glory disc anomaly OAVS: oculo-auriculo-vertebral spectrum OCCS: oculocerebrocutaneous syndrome PBS: Poretti-Boltshauser syndrome TORCH: toxoplasmosis, other agents (such as HIV, syphilis, and Zika), rubella, cytomegalovirus, and herpes simplex virus WMS: Weill-Marchesani syndrome WWS: Walker-Warburg syndrome
2026-07-30 | Triple-AAV intein-mediated gene therapy ameliorates dystrophic phenotype in MDC1A mice.
Several therapies using adeno-associated viruses (AAVs) as a gene delivery tool have received marketing approval in the past. However, potential applications of AAVs are limited by their restricted gene packaging capacities (<4.7 kb). Many monogenic diseases are caused by large complex genes with hundreds of pathogenic variants that exceed AAV capacity. Merosin-deficient congenital muscular dystrophy type 1A is a severe monogenic recessive disease caused by the absence of functional copies of the LAMA2 gene. To date, no treatment options are available, with the most promising approach being gene replacement therapy to provide a functional copy. The LAMA2 coding sequence, spanning 9.3 kb, encodes laminin-α2, a subunit of the trimeric protein Laminin-211 found in the basement membrane of skeletal muscle cells and Schwann cells. Efforts have been focused on gene or protein replacement along with basement membrane engineering. Here, we exploit the ability of inteins to reconstitute full-length protein in a scarless manner. Using a combination of three AAVs, each encoding one fragment of the laminin-α2 protein flanked by a short split intein, resulted in the complete reconstitution of Laminin-α2 and an improvement of the histopathological features of the dy2j dystrophic mouse model.
2026-06-15 | Preclinical efficacy of a gene therapy for CHKB-mediated muscular dystrophy.
Loss-of-function variants of the CHKB gene cause an autosomal recessive disease described as an early onset congenital megaconial (large peripheral mitochondria) muscular dystrophy. CHKB encodes choline kinase β, the first enzyme in the biochemical pathway for synthesis of the major membrane phospholipid phosphatidylcholine. Chkb -/- mice recapitulate the human disease with affected skeletal muscle displaying a decrease in strength, myofiber atrophy, megaconial mitochondria, fat accumulation within muscle cells, and an increase in muscle injury. Here, we assessed the therapeutic potential of an AAV therapy for the treatment of CHKB-mediated muscular dystrophy. Chkb -/- mice were injected once suborbitally with three different doses of recombinant AAV9 (rAAV9) encoding human CHKB under control of a constitutive and ubiquitous promoter (AAV9-CHKB). The AAV9-CHKB-treated mice were biochemically and phenotypically indistinguishable from the wild type mice. In the Chkb -/- mouse model, all doses resulted in expression of the CHKB protein and restored choline kinase β enzyme activity, body and muscle weight, and normal muscle cell physiology, and they prevented lipid metabolism imbalance and increased the capacity to walk. These findings point to AAV9-mediated gene therapy as a potential treatment for CHKB-mediated disease.
proteins
2026-02-04 | Dual AAV gene therapy using laminin-linking proteins ameliorates muscle and nerve defects in LAMA2-related muscular dystrophy.
Adeno-associated virus (AAV)-mediated gene replacement holds promise for treating genetic diseases but faces challenges due to the limited packaging capacity and potential immune responses to transgene products, especially in patients lacking endogenous protein. LAMA2-related muscular dystrophy (LAMA2 MD), a severe congenital disorder caused by loss of laminin-α2, presents both hurdles: the LAMA2 gene exceeds AAV capacity, and severely affected patients do not produce the native protein. Here, we developed an AAV-based therapy using two engineered linker proteins derived from endogenously expressed components. These linker proteins restore laminin receptor binding and polymerization, enabling reassembly of a functional basement membrane. Dual AAV delivery of the linkers in a severe LAMA2 MD mouse model resulted in robust expression and significant improvements in muscle histology and function. Employing myotropic capsids enabled therapeutic efficacy at lower vector doses. However, muscle-specific targeting unmasked a LAMA2-related peripheral neuropathy. To address this, we expressed one linker under a muscle-specific promoter and the other under a ubiquitous promoter, delivered via AAV9 or AAV8. This approach achieved near-complete phenotypic restoration when administered neonatally and provided significant benefit when given at progressed disease stages. Our strategy offers a mutation-independent, size-compatible, and potentially immune-tolerable treatment for LAMA2 MD with broad clinical potential.
2025-10-21 | Spatial proteomics reveals recombinant human laminin-111 restores adhesion signaling to laminin-α2-deficient muscle.
Laminin-α2-related congenital muscular dystrophy (LAMA2-CMD) is a severe neuromuscular disorder caused by mutations in the LAMA2 gene, leading to loss of heterotrimers laminin-211/221, key components of the skeletal muscle extracellular matrix. Their absence disrupts adhesion between the cytoskeleton and extracellular matrix, resulting in progressive muscle wasting. Laminin-211/221 interacts with adhesion complexes such as the dystrophin/utrophin glycoprotein complex and α7β1-integrin. However, the regulatory mechanisms of these laminin-binding complexes and the broader role of laminin's influence on the formation of the macromolecular network in skeletal muscle remain unclear. We previously demonstrated that delivering mouse laminin-111 to the dyW-/- mouse model of LAMA2-CMD prevented disease progression, improved strength, and extended survival. We hypothesize that laminin-111, the embryonic laminin isoform, restores key adhesion-signaling networks. Using spatial proteomics on patient and mouse muscle, we identified loss of essential signaling components: heat shock proteins 27 and 70, c-Jun N-terminal kinase, and glucose transporter 1 in laminin-α2-deficient muscle. Treatment with recombinant human laminin-111 (rhLAM-111) restored protein localization, reduced ROS, and promoted glycolytic, prosurvival signaling. These findings highlight laminin's role in maintaining muscle homeostasis and metabolism and support the therapeutic potential of rhLAM-111 for treating LAMA2-CMD by restoring adhesion and intracellular signaling in dystrophic muscle.
2024-05-24 | Prophylactic immunoglobulin therapy for pediatric congenital myotonic dystrophy.
Congenital Myotonic Dystrophy (CMD) is an autosomal dominant hereditary disease caused by mutations in the dystrophia myotonica protein kinase gene. Patients with CMD often exhibit low immunoglobulin (Ig) G levels. While Ig replacement therapy for low IgG levels has been reported in several adult cases, there have been no reports on pediatric patients. This study presents a first pediatric case where Ig replacement therapy effectively eliminated susceptibility to infections. The CMD patient, a 1-year-old Japanese female with a history of premature birth and necrotizing enterocolitis, developed recurrent severe bacterial infections due to hypogammaglobulinemia. Intravenous immunoglobulin (IVIG) (600 mg/kg/month) was administered but failed to maintain sufficient serum trough IgG levels. The dosage was increased to 2 g/kg/month, and later, the treatment shifted to subcutaneous immunoglobulin (SCIG), resulting in a stable serum trough IgG level above 700 mg/dL for one year. The cause of hypogammaglobulinemia in CMD patients remains unclear, but potential mechanisms, including IgG-mediated hypercatabolism by alterations in the neonatal Fc receptor, have been considered. Genetic testing ruled out common variable immunodeficiency, and other potential causes were excluded. The study suggests that higher doses of IVIG or SCIG can effectively prevent severe infections associated with CMD-induced hypogammaglobulinemia in children. This case report sheds light on the efficacy of immunoglobulin therapy in pediatric congenital myotonic dystrophy (CMD). We anticipate that our findings will have a positive impact on clinical practice by providing insights into the prevention of severe infections associated with CMD-induced hypogammaglobulinemia. This research is of great interest to the readers of the journal as it addresses an unmet need in pediatric CMD management by providing a strategy for successful immunoglobulin therapy for the treatment of pediatric CMD.
2023-08-22 | PAX7, a Key for Myogenesis Modulation in Muscular Dystrophies through Multiple Signaling Pathways: A Systematic Review
Muscular dystrophy is a heterogenous group of hereditary muscle disorders caused by mutations in the genes responsible for muscle development, and is generally defined by a disastrous progression of muscle wasting and massive loss in muscle regeneration. Pax7 is closely associated with myogenesis, which is governed by various signaling pathways throughout a lifetime and is frequently used as an indicator in muscle research. In this review, an extensive literature search adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed to identify research that examined signaling pathways in living models, while quantifying Pax7 expression in myogenesis. A total of 247 articles were retrieved from the Web of Science (WoS), PubMed and Scopus databases and were thoroughly examined and evaluated, resulting in 19 articles which met the inclusion criteria. Admittedly, we were only able to discuss the quantification of Pax7 carried out in research affecting various type of genes and signaling pathways, rather than the expression of Pax7 itself, due to the massive differences in approach, factor molecules and signaling pathways analyzed across the research. However, we highlighted the thorough evidence for the alteration of the muscle stem cell precursor Pax7 in multiple signaling pathways described in different living models, with an emphasis on the novel approach that could be taken in manipulating Pax7 expression itself in dystrophic muscle, towards the discovery of an effective treatment for muscular dystrophy. Therefore, we believe that this could be applied to the potential gap in muscle research that could be filled by tuning the well-established marker expression to improve dystrophic muscle.
2022-10-31 | The extracellular matrix differentially directs myoblast motility in distinct forms of muscular dystrophy
ABSTRACT Extracellular matrix (ECM) pathologic remodeling underlies many fibrotic disorders, including muscular dystrophy. Tissue decellularization removes cellular components while leaving behind ECM components. We generated “on-slide” decellularized tissue slices from genetically distinct dystrophic mouse models. The ECM of dystrophin-and sarcoglycan-deficient muscles had marked thrombospondin 4 deposition, while dysferlin-deficient muscle had excess decorin. Annexins A2 and A6 were present on all dystrophic decellularized ECMs, but annexin matrix deposition was excessive in dysferlin-deficient muscular dystrophy. Adeno-associated viral expression of annexin A6 specifically in muscle resulted in annexin A6 deposition throughout the ECM, indicating muscle as a source of this ECM protein. C2C12 myoblasts seeded onto decellularized matrices displayed differential myoblast mobility. Dystrophin-deficient decellularized matrices inhibited myoblast mobility while dysferlin-deficient decellularized matrices enhanced myoblast movement. Myoblasts treated with recombinant annexin A6 increased mobillity similar to that seen on dysferlin-deficient decellularized matrix. These findings demonstrate specific fibrotic signatures elicit effects on myoblast activity. TEASER Fibrosis in muscular dystrophy has differential effects on myoblasts HIGHLIGHTS Spatial architecture and composition of the ECM differ across genetically distinct forms of muscular dystrophy, especially with respect to Annexin A6 protein deposition Matrix from dystrophin-mediated muscular dystrophy inhibits myoblast movement Matrix from dysferlin-deficient muscular dystrophy promotes myoblast motility Annexin A6 was sufficient to enhance myoblast motility
oligonucleotides
2026-09-30 | Gapmer and Mixmer Antisense Oligonucleotides to Selectively Suppress the Mutant Allele in COL6A Genes in Dominant Ullrich Congenital Muscular Dystrophy.
Allele-specific gene silencing with antisense oligonucleotides (ASOs) or small interfering RNA (siRNA) is a promising strategy for disorders driven by dominant gain-of-function effects. We here present two antisense approaches, gapmer and mixmer ASOs, to mitigate the dominant-negative mechanism underlying Ullrich congenital muscular dystrophy (UCMD) caused by recurrent COL6A3 mutations. We outline the details of methods that our lab has used. The methods comprise the rational ASO design (classical gapmers and mixmers to enhance allele selectivity), in vitro evaluation of allele-specific mRNA knockdown, and protein-level functional assessment. Patient-derived dermal fibroblasts harboring COL6A3 c.6210+1G>A or c.6135_6152del were used as cellular models.
2025-09-07 | Fukuyama congenital muscular dystrophy: Clinical features and therapeutic advances.
Fukuyama congenital muscular dystrophy (FCMD, a severe form of muscular dystrophy characterized by brain structural anomalies and ocular complications due to neuronal migration disorders, is notably limited mainly to Japan. Ninety percent of patients are unable to walk throughout their lives and die before the age of 20 due to respiratory failure and cardiomyopathy. At present, there is no cure. The founder variant, a 3-kb insertion in FKTN, is an SVA (SINE-VNTR-Alu) retrotransposon, and FCMD is a splicing disorder attributable the exon trapping function of this retrotransposon. A splicing modulation therapy targeting exon-trapping based on using antisense nucleic acids to block abnormal splicing is under development, and clinical trials have begun. Additionally, it was clarified that the gene product of FKTN is a glycosyltransferase that transfers ribitol-5-phosphate from cytidine diphosphate ribitol, a precursor for the synthesis of the O-mannosyl glycans of α-dystroglycan, a cell membrane component. This finding raises hopes for a prodrug therapy. Though patient numbers were small, previous clinical studies suggested that steroids are effective in FCMD. Thus, phase II clinical trials are underway with the aim of obtaining insurance approval. This review provides an overview of the clinical course and current status of treatments being developed for FCMD.
2025-08-27 | Muscle transcriptome profiling reveals novel molecular pathways and biomarkers in laminin-α2 deficient patients
Merosin-deficient congenital muscular dystrophy (LAMA2-RD) is caused by LAMA2 gene mutations, coding for laminin-211 (merosin) α2 subunit. LAMA2 mutations leading to complete laminin-211 absence result in an invariably severe clinical phenotype, with profound muscle weakness and respiratory insufficiency. Milder phenotypes are often associated with mutations allowing the production of a partially functional protein. While several dysregulated genes/pathways linked to LAMA2-RD muscle loss are known, an in-depth characterization of LAMA2-RD muscle gene expression profile in patients with mutations differentially affecting LAMA2 expression is lacking. We generated muscle transcriptomic data from patients with either complete or partial laminin-211 deficiency, and identified pathways linked to the most dysregulated processes. Genes related to fibrosis, inflammation and metabolism were similarly expressed in both patient cohorts. However, a subset of novel pro-fibrotic and pro-inflammatory genes were exclusively expressed in patients (and mice) completely lacking laminin-211, indicating aspects exacerbated in this cohort. Our work characterizes the main contributors of human LAMA2-RD pathology, providing insight into molecular pathways that could be used as disease biomarkers or as targets for therapeutic approaches.
2025-07-28 | An Overview of Recent Advances and Clinical Applications of Exon Skipping and Splice Modulation for Muscular Dystrophy and Various Genetic Diseases.
Exon skipping and splice modulation using synthetic antisense oligonucleotides (AONs) are therapeutic approaches to delay or arrest the progression of genetic diseases. AON-mediated exon skipping modifies pre-mRNA splicing to correct the reading frame of genes responsible for disease and modulate a protein structure, providing therapeutic benefits. Studied for over two decades, exon skipping AONs have received conditional marketing authorization for Duchenne muscular dystrophy (DMD). The US Food and Drug Administration (FDA) has granted accelerated approval for four AONs to skip a single DMD exon for treating patients with DMD: eteplirsen for exon 51 skipping, golodirsen and viltolarsen for exon 53 skipping, and casimersen for exon 45 skipping. Various preclinical and clinical trials are underway with AONs targeting other exons and ones loading bioconjugates, such as cell-penetrating peptides and antibodies to enhance the exon skipping ability. Besides AONs targeting pre-mRNA, genomic DNA target exon skipping using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technology, which holds promise in current preclinical trials for DMD. In hopes of achieving clinical success parallel to DMD, exon skipping and splice modulation are studied in other muscular dystrophies, such as Fukuyama congenital muscular dystrophy (FCMD), dysferlinopathy including limb-girdle muscular dystrophy type 2B (LGMD2B), Miyoshi myopathy (MM), and distal anterior compartment myopathy (DMAT), myotonic dystrophy, and merosin-deficient congenital muscular dystrophy type 1A (MDC1A). Splice-modulating AONs have also been extensively tested in other inherited diseases, such as Usher syndrome, dystrophic epidermolysis bullosa (DEB), fibrodysplasia ossificans progressiva (FOP), and allergic diseases. This chapter will introduce the developmental status of exon skipping and splice-modulating therapies for genetic diseases.
2025-07-28 | Exon-Skipping Using Antisense Oligonucleotides for Laminin-Alpha2-Deficient Muscular Dystrophy.
Phosphorodiamidate morpholino oligomer (PMO)-mediated exon-skipping is among the more promising approaches available for the treatment of several neuromuscular disorders, including Duchenne muscular dystrophy. The main weakness of this treatment arises from the low efficiency and sporadic nature of the delivery of neutrally charged PMOs into muscle fibres, the mechanism of which is unknown. Recently, using wild-type and dystrophic mdx52 mice, we showed that muscle fibres took up PMOs more efficiently during myotube formation. Interestingly, we detected PMO mainly in embryonic myosin heavy chain-positive regenerating fibres through in situ hybridisation. Next, we tested the therapeutic potential of PMOs in laminin-alpha2 (laminin-α2) chain-null dy3K/dy3K mice, a model of merosin-deficient congenital muscular dystrophy 1A (MDC1A or LAMA2-related muscular dystrophy: LAMA2-MD) with active muscle regeneration. We confirmed the recovery of the laminin-α2 chain following the skipping of the mutated exon 4 in dy3K/dy3K mice, which prolonged the lifespan of the animals slightly. These findings support the theory that PMO entry into fibres is dependent on the developmental stage in myogenesis rather than on dystrophin-deficient muscle membranes, and recommend a platform for the future development of PMO-mediated therapies for a variety of muscular disorders, such as LAMA2-MD, that involve active muscle regeneration. Herein, we describe the methods for PMO transfection/injection and the evaluation of the efficacy of exon-skipping in the laminin-α2-deficient dy3K/dy3K mouse model both in vitro and in vivo.
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2026-07-02 | Muscle-Specific Kinase Signaling and Its Therapeutic Potential.
The function of the neuromuscular junction (NMJ) is compromised in many neuromuscular diseases (NMDs) such as autoimmune or congenital myasthenia gravis (MG), amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), and muscular dystrophies. The NMJ contains muscle-specific kinase (MuSK), which is a critical regulator of NMJ integrity and function. Activating the MuSK signaling cascade may have therapeutic potential in several of these NMDs that are characterized by impaired neuromuscular communication. The MuSK signaling cascade consists of different components and can be activated with interventions at different levels. In the past years, different therapeutic strategies using an engineered recombinant agrin comprised of the C-terminal fragment of the protein (mini-agrin), gene therapy of key proteins in this pathway, agonist MuSK antibodies, and SRC homology 2 domain-containing phosphotyrosine phosphatase 2 (SHP2) inhibitors have been further developed for this purpose. Each of these strategies engages distinct signaling components: mini-agrin, both as recombinant protein and gene therapy, enhances agrin-Lrp4-MuSK interaction; Dok7 gene therapy amplifies MuSK phosphorylation; Lrp4 gene therapy enhances agrin responsiveness; MuSK agonist antibodies bypass upstream defects and promote downstream signaling; SHP2 inhibitors prolong the duration of active MuSK signaling. These therapeutic strategies have ameliorated NMJ integrity and function in several preclinical models of MG, motor neuron diseases, and muscular dystrophies. In this review, we highlight MuSK signaling as a possible therapeutic target, describe the therapeutic efficacy of intervention in MuSK signaling in different NMDs, and present an outlook on future clinical development.
2025-09-29 | [iPS cell-based therapy for muscular disorders].
Induced pluripotent stem cells (iPSCs) have been used in research for the development of treatments for various intractable diseases due to their unlimited proliferative and multipotent potential. We are aiming to develop novel therapies for intractable muscular diseases using iPS cells by two approaches i.e. cell therapy and drug screening. In this presentation, I focus on the cell therapy research. We have developed a differentiation induction method that mimics the developmental stages and have succeeded in inducing skeletal muscle stem cells that are applicable to cell transplantation therapy. We have found that cell transplantation into Duchenne muscular dystrophy (DMD) model mice is effective in regenerating more than 10% of dystrophin-positive fibers. In addition, some of the cells have been engrafted as satellite cells in vivo, and it is expected that the therapeutic effect will continue for a long period of time. As for the efficacy to the motor function, we have recently revealed that the regeneration of dystrophin positive myofibers in DMD model mice mainly ameliorates muscle fatigue tolerance rather than maximal contraction force in vivo. We have also developed a differentiation method to induce mesenchymal stromal cells (MSCs) from iPSCs. Transplantation of iPSC-derived MSCs (iMSCs) into Ullrich congenital muscular dystrophy (UCMD) model mice enabled the restoration of collagen type VI which resulted in enhancement of muscle regeneration. Interestingly, somatic MSCs such as bone marrow-derived MSC or adipose-derived MSC do not have therapeutic effect even they can also restore collagen type VI by the transplantation. We have recently found one of the candidates which is responsible for the muscle regeneration and is specifically expressed in the iMSCs.
2025-09-19 | Antxr2-mediated fine-tuning of Collagen VI ensures skeletal muscle function
ABSTRACT Tissue function relies on the extracellular matrix (ECM) that surrounds cells, providing structural and biochemical support. The complex ECM composition depends on an adequately tuned balance between the deposition and degradation of each of its components. Disequilibrium may cause disease, as observed for Collagen VI (COL6), for which mutations lead to muscular dystrophy. Here, we investigated the role of Anthrax Toxin Receptor 2 (ANTXR2/CMG2), a receptor that controls the turnover of COL6, in skeletal muscle. We show that ANTXR2 is mostly expressed by fibro-adipogenic precursors and that its deficiency in ANTXR2 null ( Antxr2 -/- ) mice leads to a premature and irregular COL6 accumulation in intramuscular connective tissue. This results in tissue stiffening and gradual, non-functional muscle hypertrophy, marked by impaired locomotion and myopathic signs. Our findings further indicate that COL6 accretion drives these alterations, as revealed by Antxr2 -/- ::Col6a1 -/- double knockout mice, highlighting the essential role of ANTXR2-mediated COL6 remodeling in maintaining ECM homeostasis and muscle functionality. SIGNIFICANCE STATEMENT Remodelling of the extracellular matrix (ECM) was long thought to rely almost exclusively on extracellular proteases. Increasing evidence, however, indicates that some ECM components may undergo intracellular degradation following receptor-mediated endocytosis, as we have found for Collagen VI (COL6). Here, we identify the COL6 receptor ANTXR2 as a critical regulator of ECM turnover in skeletal muscle.. When ANTXR2 is absent, COL6 builds up, followed by the accumulation of fibrillar collagens, without changes in gene expression. These alterations in muscle ECM lead to increased stiffness, myofiber defects and impaired locomotor activity. Our findings establish ANTXR2 as a key regulator in ECM remodelling, offering new insights into potential treatments for conditions associated with defective ECM remodeling, such as aging and congenital muscular dystrophies.
2025-07-08 | Anti-myogenic and profibrotic effect of serum from patients affected by muscular laminopathies.
Emery-Dreifuss Muscular Dystrophy type 2 (EDMD2) and LMNA-related congenital muscular dystrophy (L-CMD) are caused by mutations in LMNA gene. Both pathologies are characterized by joint contractures, muscle weakness and wasting and cardiac involvement. In the last few years, circulating factors have been proposed to play a critical role in the pathogenesis of these diseases. Based on this consideration, we studied the effect of laminopathic serum on the myogenic differentiation in healthy human myoblasts in culture. We observed impaired myogenesis and increased fibrosis in myoblast cultures conditioned with laminopathic serum and a dramatic increase in the level of profibrotic and proinflammatory cytokines in the cell culture supernatants. These results strongly support the pathogenic role of circulating factors in muscular laminopathies and pave the way to a possible therapeutic strategy.
2025-06-08 | Breakthrough in Functional Muscle Regeneration: Biomimetic Collagen Scaffold Restores Abdominal Wall Defects in a VML-rabbit Model
Abstract Functional regeneration of volumetric muscle loss (VML) remains a significant challenge in the field of regenerative medicine. We have developed a novel biomimetic scaffold (0.4 mm thick hernia patch) derived from soluble collagen. This biomimetic scaffold exhibits exceptional strength, low immunogenicity, and structurally mimics the natural muscle fiber arrangement. The scaffold is utilized to repair a VML rabbit model (30 × 30 mm defect in abdominal wall) using nylon sutures for connection. It was observed that the VML site was gradually covered by regenerated tissue, which consisted of 2-3 mm thick functional muscle. By 32 weeks post-surgery, the newly formed muscle tissue had covered the majority of the VML area, as evidenced by morphological observations and histological evaluations. Approximately 24 weeks after surgery, the scaffold underwent complete degradation. This degradation exhibited a strong correlation with muscle regeneration. Furthermore, it was observed that the nylon sutures gradually migrated towards the VML center as muscle regeneration progressed, and nylon sutures exhibited an adverse impact on muscle regeneration.. The study did not employ exogenous cells or growth factors. However, the collagen scaffold effectively stimulated endogenous muscle regeneration. In contrast to the previous limited partial recovery or fibrotic scar healing, the collagen scaffold successfully induced genuine structural and functional muscle regeneration. The 0.4 mm thick scaffold (hernia patch) exhibits a different structure from the 2-3 mm thick natural abdominal muscle wall. This suggests that a simple scaffold can regenerate functional tissue with a complex structure. This research represents the first successful functional regeneration of VML in clinically relevant animal models through the utilization of artificial materials. This technology possesses transformative potential in the treatment of muscle defects arising from trauma, tumor resection, hernia, or congenital anomalies. Furthermore, it holds substantial medical potentials in addressing neuromuscular diseases, such as Duchenne muscular dystrophy (DMD), amyotrophic lateral sclerosis (ALS), and spinal muscular atrophy (SMA), by collaborating with advanced technologies including CRISPR-Cas9, adeno-associated virus (AAV) gene therapy, and stem cell technology.
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Drug Discovery Landscape
4 orphan drug designations for Congenital muscular dystrophy.
4 orphan drug designations for Congenital muscular dystrophy.
Drug | Therapy type | Orphan designation | Clinical trial status | Sponsor |
|---|---|---|---|---|
adeno associated vector (serotype AAV MYO2) encoding the fukutin related protein (ssAAVMYO2.tMCK.FKRP) | gene therapies | FDA | — | Cure Rare Disease |
Insulin-like Growth Factor-1 | proteins | FDA | Sarcomed AB | |
Human laminin-111, recombinant | proteins | EMA | — | Maxia Strategies-Europe Limited |
omigapil | small molecules | FDA | Santhera Pharmaceuticals (Switzerland) Limited |
“Terminated” – programs with discontinued clinical trials, or with no updates reported for 5 years after completion or 12 years after the last trial started.
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