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VeloGene Biotech & GenAssist Ltd
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Duchenne Muscular Dystrophy Mouse Model Project
Accelerating Global New Drug R&D:
First-Ever Platform Featuring Serialized Humanized Mouse Models for Duchenne Muscular Dystrophy (DMD) Launched
What is Duchenne Muscular Dystrophy (DMD)？
Duchenne Muscular Dystrophy (DMD) is a severe, progressive, and currently incurable genetic disorder characterized by relentless muscle wasting and lethal cardiorespiratory failure. As an X-linked recessive condition, it predominantly affects males, with an incidence of approximately 1 in 3,500 to 5,000 live male births.
Why is the DMD gene particularly prone to mutations compared to other human genes?
The disease is driven by mutations in the DMD gene—the largest known human gene—which result in the absence or dysfunction of the dystrophin protein. Dystrophin acts as a crucial mechanical shock absorber, anchoring the intracellular cytoskeleton of muscle fibers to the extracellular matrix via the dystrophin-associated glycoprotein complex (DGC).
Why is the muscle regeneration process eventually exhausted in DMD patients?
Without functional dystrophin, normal muscle contractions cause continuous sarcolemmal micro-tears. This chronic membrane fragility triggers calcium influx, rampant inflammation, and continuous cycles of muscle necrosis. Over time, the muscle’s regenerative capacity is exhausted, and functional muscle fibers are progressively replaced by fibrotic scar tissue and fat.
The Role of Preclinical Mouse Models for DMD research
The translation of potential therapeutics—such as gene therapy, CRISPR/Cas9 editing, and antisense oligonucleotides—from the bench to the clinic relies heavily on rigorous in vivo testing. However, modeling DMD in mice presents a unique challenge: the genetic equivalent of the disease in mice does not perfectly mirror the severity of human pathology.
Researchers utilize several distinct mouse strains, each offering specific advantages for evaluating different aspects of disease progression and therapeutic efficacy.
The Classic mdx Mouse (BL10-mdx)
The C57BL/10ScSn-Dmd^mdx strain, commonly known as the mdx mouse, has been the primary workhorse of DMD preclinical research for over four decades. It harbors a spontaneous nonsense point mutation in exon 23 of the Dmd gene, leading to a premature stop codon and the loss of full-length dystrophin.
- Advantages:It is genetically and biochemically homologous to human DMD, is highly viable, and is easy to breed in large numbers.
- Limitations:Despite lacking dystrophin, mdx mice exhibit a remarkably mild clinical phenotype compared to human patients. After a brief peak of muscle necrosis at 3 to 4 weeks of age, the mice undergo intense muscle regeneration and pseudohypertrophy, allowing them to maintain near-normal lifespans and mobility. This resilience is largely attributed to compensatory murine rescue mechanisms, such as the upregulation of the homologous structural protein utrophin. The diaphragm is the only muscle in the mdx mouse that progressively develops severe fibrosis comparable to human pathology.
The D2-mdx Mouse (Severe Phenotype)
To address the mild phenotype of the classic model, researchers introduced the mdx mutation onto a different genetic background: the DBA/2J strain, creating the D2-mdx mouse.
- Pathological Relevance:The D2-mdx mouse exhibits a much more severe and progressive dystrophic phenotype that better recapitulates human DMD.
- Key Differences:Unlike the hypertrophic response seen in classic mdx mice, D2-mdx mice display pronounced muscle atrophy, impaired regenerative capacity, and heightened transforming growth factor-beta (TGF-β) signaling, which actively accelerates tissue fibrosis. Furthermore, they develop cardiac dysfunction significantly earlier than their BL10-mdx counterparts, making them a superior model for evaluating therapies targeting late-stage disease and cardiomyopathy.
Double-Transgenic Models
To artificially force a severe phenotype on the standard mdx background, researchers have engineered double-knockout models that disable the mouse’s natural compensatory pathways.
- The mdx/utrophin KO:By eliminating both dystrophin and its compensatory counterpart, utrophin, these mice develop severe, progressive muscle wasting, pronounced spinal curvature (kyphosis), and premature mortality by 4 to 20 weeks of age. While highly useful for efficacy testing under severe pathological conditions, it is important to note that the total absence of utrophin represents a genetic scenario that does not exist in human DMD patients.
Related Products
While early research relied heavily on standard rodent models (such as the classic mdx mouse), these traditional platforms present significant translational challenges:
- Phenotypic Discordance:Rodent models often exhibit milder disease progression due to compensatory mechanisms like utrophin upregulation.
- Sequence Non-Identity:Emerging precision modalities—such as AAV-delivered micro-dystrophins, exon-skipping antisense oligonucleotides (ASOs), and CRISPR/Cas9 base editors—require exact target human DNA/RNA sequences to demonstrate safety and efficacy.
To resolve these critical bottlenecks, GenAssist Ltd and International VeloGene Biotechnology Co., Ltd entered a strategic global partnership to provide researchers and pharmaceutical developers with direct access to fully validated, humanized DMD mouse models. Currently, DMD mouse models of hE45delE44, hE50delE51, hE51delE52hE53 are ready for preparation and sale.
Building upon this strategic collaboration, our joint enterprise has fully mastered the core technology behind advanced humanized genetic engineering. No matter the specific variant, unique exon deletion profile, or alternative genetic background required for your Duchenne Muscular Dystrophy (DMD) research, our platform possesses the end-to-end capability to custom-engineer and deliver tailored rodent models with absolute precision.
| Strain | Modeling Type | Application Field | See Details |
|---|---|---|---|
| DMDhE50delE51 | Humanize |
| View |
| DMDhE51delE52hE53 | Humanize |
| View |
| DMDhE45delE44 | Humanize |
| View |