Loss of cell-autonomously secreted laminin-α2 drives muscle stem cell dysfunction in LAMA2-related muscular dystrophy
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ABSTRACT:
PROVIDER: PRJNA1321711 | ENA |
REPOSITORIES: ENA
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Project description:The extracellular matrix protein laminin-α2 is essential for preserving the integrity of skeletal muscle fibers during contraction. Its importance is reflected by the severe, congenital LAMA2-related muscular dystrophy (LAMA2 MD) caused by loss-of-function mutations in the LAMA2 gene. While laminin-α2 has an established role in structurally supporting muscle fibers, it remains unclear whether it exerts additional functions that contribute to the maintenance of skeletal muscle integrity. Submitted transcriptomic data represents gene expression profile of control and LAMA2-deficient human myogenic precursor cells derived from induced pluripotent stem cells which was analyzed to better understand the role of laminin-α2 in human cells.
2025-09-14 | GSE307443 | GEO
Project description:Adeno-associated virus (AAV)-mediated gene replacement holds promise for treating genetic diseases but faces challenges due to AAV’s 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.
2026-02-03 | GSE312724 | GEO
Project description:LAMA2-deficient congenital muscular dystrophy (LAMA2-CMD) is a severe neuromuscular disorder caused by LAMA2 mutations, leading to muscle degeneration, chronic inflammation, and fibrosis. Histopathological assessment of muscle biopsies from LAMA2-CMD patients and mouse models show clear evidence of inflammation, which oftentimes are regarded as one of the typical dystrophic hallmarks. However, the composition of immune cells in the laminin-deficient muscles remain understood. Consequently, targeted pharmacological intervention to reduce inflammation has never been tested. In this study, we characterized the immune landscape in dyW mouse model of LAMA2-CMD using RNA sequencing and flow cytometry. Transcriptomic analysis of dyW quadriceps identified 2,143 differentially expressed genes, with most of the upregulated genes belong to immune-related pathways. Lgals3 (Galectin-3) was significantly upregulated (log₂FC = 4.27, FDR p-value= 9.21x10-88) and identified as a key upstream regulator of the immune-related pathways. In parallel, flow cytometry analysis revealed elevated leukocyte (CD45⁺) infiltration, with macrophages as the predominant cell population. Pro-inflammatory (M1) macrophages were increased, whereas anti-inflammatory (M2) macrophages remained low, indicating persistent inflammation and impaired resolution. Interestingly, Galectin-3+ macrophages were significantly enriched, which strongly suggest that Galectin-3 drives inflammation in LAMA2-CMD. Treatment of dyW mice with TD-139, a Galectin-3 inhibitor, reduced leukocyte infiltration, decreased Galectin-3+ macrophages, and shifted macrophage polarization toward an M2 anti-inflammatory profile. In addition, RNA sequencing of TD-139-treated dyW muscles showed upregulation of muscle repair pathways and downregulation of fibrosis-related genes. These findings establish Galectin-3-expressing macrophages as an important player in LAMA2-CMD pathophysiology. Importantly, it warrants further investigation on the therapeutic potential of TD-139-mediated inhibition of Galectin-3, including long-term preclinical study, in LAMA2-CMD and potentially other dystrophic conditions driven by chronic immune activation.
2025-03-25 | GSE292894 | GEO
Project description:Adeno-associated virus (AAV)-mediated gene replacement holds promise for treating genetic diseases but faces challenges due to AAVs limited packaging capacity and potential immune responses to transgene products - particularly in cross-reactive immunologic material (CRIM) - negative patients. LAMA2-related muscular dystrophy (LAMA2 MD), a severe congenital disorder caused by loss of laminin-a2, presents both hurdles: the LAMA2 gene exceeds AAV capacity, and severely affected patients lack endogenous protein, increasing immunogenicity risk. Here, we developed an AAV-based therapy using two engineered linker proteins derived from endogenously expressed components. These linkers 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. Using myotropic capsids allowed for efficacy at reduced vector doses. However, muscle-only targeting unmasked 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 still 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.
2025-07-24 | MSV000098631 | MassIVE
Project description:Laminin (merosin) deficient muscular dystrophy in dy/dy mouse diaphragm muscle, 8 weeks old Keywords: muscle, muscular dystrophy, laminin, merosin, diaphragm, mouse
2006-03-16 | GSE3252 | GEO
Project description:We report a a large deletion in the gene encoding for laminin subunit α2 (Lama2) in CHO pgsA745.
2016-11-20 | GSE75521 | GEO
Project description:Although recessive mutations in LAMA2 are already known to cause laminin α2-related muscular dystrophy, a rare neuromuscular disorder, large deletions or duplications within this gene are not well-characterized. In this study, we applied next-generation sequencing-based copy number variation profiling in 114 individuals clinically diagnosed with laminin α2-related muscular dystrophy, including 96 who harboured LAMA2 mutations and 34 who harboured intragenic rearrangements. In total, we detected 18 distinct LAMA2 copy number variations that have been reported only among Chinese, 10 of which are novel. The frequency of CNVs in the cohort was 19.3%. Deletion of exon 4 was detected in 10 alleles of eight patients, accounting for 27% of all copy number variations. These patients are Han Chinese and were found to have the same haplotype and sequence at the breakpoint junction, suggesting that exon 4 deletion is a founder mutation in Chinese Han and a mutation hotspot. Moreover, the data highlight our approach, a modified next-generation sequencing assay, as a robust and sensitive tool to detect LAMA2 variants; the assay identifies 85.7% of breakpoint junctions directly alongside sequence information. The method can be applied to clinical samples to determine causal variants underlying various Mendelian disorders.
| S-EPMC6177444 | biostudies-literature
Project description:Dual AAV gene therapy using laminin-linking proteins ameliorates muscle and nerve defects in LAMA2-related muscular dystrophy
| PRJNA1375781 | ENA
Project description:Congenital muscular dystrophy with laminin α2 chain-deficiency (LAMA2-CMD) is a severe neuromuscular disorder without a cure. Using transcriptome and proteome profiling as well as functional assays, we previously demonstrated significant metabolic impairment in skeletal muscle from LAMA2-CMD patients and mouse models. Reactive oxygen species (ROS) increase when oxygen homeostasis is not maintained and, here, we investigate whether oxidative stress indeed is involved in the pathogenesis of LAMA2-CMD. We also analyze the effects of two antioxidant molecules, N-acetyl-L-cysteine (NAC) and vitamin E, on disease progression in the dy2J/dy2J mouse model of LAMA2-CMD. We demonstrate increased ROS levels in LAMA2-CMD mouse and patient skeletal muscle. Furthermore, NAC treatment (150 mg/kg IP for 6 days/week for 3 weeks) led to muscle force loss prevention, reduced central nucleation and decreased the occurrence of apoptosis, inflammation, fibrosis and oxidative stress in LAMA2-CMD muscle. In addition, vitamin E (40 mg/kg oral gavage for 6 days/week for 2 weeks) improved morphological features and reduced inflammation and ROS levels in dy2J/dy2J skeletal muscle. We suggest that NAC and to some extent vitamin E might be potential future supportive treatments for LAMA2-CMD as they improve numerous pathological hallmarks of LAMA2-CMD.
| S-EPMC7139799 | biostudies-literature
Project description:LAMA2-congenital muscular dystrophy (LAMA2-CMD) is the most common congenital muscular dystrophy and is triggered by mutations in LAMA2, coding for laminin α2 chain. Several phenotypes have been associated with LAMA2-CMD, including inflammation, fibrosis and increased oxidative stress. However, it is not yet known what mechanisms are faulty, right at disease onset, which in the mouse model of LAMA2-CMD dyW/dyW has been previously established to occur between embryonic days (E) 17.5 and E18.5. This transcriptomic analysis of fetal muscle fibers perfomed at E17.5 provides critical information regarding the genes and pathways that are altered in LAMA2-CMD right at the onset of the disease.
2024-09-23 | GSE253680 | GEO