Historically, the path to developing treatments for Nemaline Myopathy (NM) has faced two significant roadblocks: a limited understanding of how the disease impacts muscle cells beyond initial genetic mutations, and a shortage of versatile lab models to rapidly test new therapeutic approaches.
An AFBS (A Foundation Building Strength) funded international collaboration led by Dr. David Mack (University of Washington, USA) and Dr. Peter Houweling (Murdoch Children’s Research Institute, Australia) is attempting to break through these barriers. Using cutting-edge Engineered Muscle Tissues (EMTs) grown from patient-derived stem cells, their teams have created renewable, functional 3D human muscle in a dish, allowing them to measure muscle force in a clinically relevant context directly.
Why This Matters:
These advanced 3D models allow researchers to test potential gene and drug therapies directly on human tissue well in advance of human clinical trials. By screening treatments in a human context early on, the team can significantly accelerate the search for effective therapies while reducing the time and cost required before moving to clinical studies.
Over the last six months, this groundbreaking research platform has yielded critical progress—from gene editing and AI-driven drug discovery to laying the foundation for models of NEB-related NM.
1. Proof of Concept: Gene Editing Triples Muscle Force
The central highlight of the lab’s recent work focuses on dominant ACTA1-related Nemaline Myopathy (specifically the R183S mutation). Using CRISPR/Cas9 gene-editing technology as “molecular scissors,” the research team successfully deleted the mutated ACTA1 allele.
The results were remarkable: after allele deletion, the engineered human muscle tissue recovered and produced three times more contractile force than before. This dramatic improvement validates allele deletion as a viable therapeutic strategy for dominant ACTA1-related NM.
2. Defining the “Threshold” for Clinical Success
While deleting 100% of mutated alleles in a petri dish is possible, achieving perfect delivery across every muscle cell in a living human body is one of gene therapy’s greatest hurdles.
To address this real-world challenge, the team is currently defining the minimum level of allele deletion needed to achieve clinically meaningful strength. By evaluating four genetically identical (isogenic) cell lines with varying degrees of deletion—0%, 34%, 52%, and 100%—they are mapping out the precise target thresholds required for future gene therapies to succeed in clinical trials.
3. AI-Powered Virtual Screening for Small-Molecule Drugs
Gene therapy isn’t the only tool being explored. In parallel, Drs. Mack and Houweling are leveraging artificial intelligence to hunt for small-molecule drugs that can stabilize the mutated protein.
Using AI-powered computer modeling, researchers have mapped the precise 3D structure of the mutated ACTA1 protein and identified two distinct “pockets” where potential drugs could bind. The team is currently conducting a virtual screening of 10,000 drug compounds to identify candidates capable of restoring protein stability. The top candidates will soon be tested directly on the lab’s 3D EMT models.
4. Expanding the Horizon: The First Human Stem Cell Model for NEB
While initial efforts focused on ACTA1, the project’s mission has always been to transform treatment discovery across all NM subtypes.
The team has now officially begun generating the first human stem cell models for nebulin (NEB)-related Nemaline Myopathy, the most common form of the disease, which affects roughly half of all NM patients. Building 3D muscle models for NEB will mark a monumental step forward in expanding drug and gene therapy testing for the broader community.
What’s Next?
Looking ahead, the Mack and Houweling labs are focused on several high-priority next steps:
- Completing partial-deletion force measurements to establish effective gene therapy dosing targets.
- Testing the top AI-selected drug candidates in 3D ACTA1 muscle tissues.
- Generating NEB iPSC lines and engineering 3D nebulin-deficient muscle tissue models.
By building renewable human tissue models and integrating advanced gene editing with AI-driven drug discovery, this project is reshaping how therapies for NM are identified, tested, and refined.
This vital international research effort is made possible through funding from A Foundation Building Strength. Together, we are building strength and driving science toward a future where effective treatments for Nemaline Myopathy may finally be a reality.
A Foundation Building Strength (AFBS) is a nonprofit organization dedicated to accelerating the development of treatments for Nemaline Myopathy. Our mission is to fund cutting-edge research to find effective treatments while providing resources and a strong community for families affected by NM. We are proud to be at the forefront of driving Nemaline Myopathy research breakthroughs forward through collaborations with research teams across the globe.
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