Neuromuscular diseases (NMDs) encompass a diverse group of disorders characterised by the dysfunction of motor neurons and skeletal muscle, resulting in profound impairments in muscle control and function. Among NMDs, motor neuron diseases (MNDs), which involve progressive degeneration of motor neurons and subsequent muscle atrophy, stand out as a particularly debilitating subset. For one of the most fatal types of MND, amyotrophic lateral sclerosis (ALS), patients have a life expectancy of just 2 to 5 years. Despite continuous efforts, effective treatments for MNDs remain elusive, largely due to the complex nature of these diseases and a lack of comprehensive understanding of their underlying mechanisms.
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September 1, 2023To address these challenges, researchers have been exploring innovative approaches to unravel the pathogenesis of MNDs. Led by Dr. Roger D. Kamm, a team of scientists at Massachusetts Institute of Technology have developed a protocol for the fabrication of a 3D microfluidic neuromuscular model that can be used to model MNDs such as ALS. This innovative approach, which utilises CELLBANKER 1 and STEM-CELLBANKER cryopreservation mediums from AMSBIO, holds significant promise in revolutionising our approach to drug discovery and understanding the development of MNDs.
Unlocking Insights with iPSCs and Optogenetics
NMDs typically involve motor neuron dysfunction, skeletal muscle cell death, or a combination of both. By co-culturing both cell types, Dr. Kamm’s neuromuscular model provides a physiologically relevant platform for the study of NMD pathogenesis. The protocol published describes the manufacturing of a microfluidic chip that contains compartments for each cell type, allowing for the separation of the motor neuron and muscle cell cultures to mimic the physiology found in living tissue. Induced pluripotent stem cells (iPSCs) from either healthy donors or ALS patients were differentiated into neural stem cells, which were expanded and cryogenically preserved using STEM-CELLBANKER from AMSBIO. When needed, the neural stem cells were thawed and further differentiated into motor neurons to be used in the 3D model. Similarly, skeletal muscle cells were also differentiated from iPSCs and employed in the model where they self-organise into muscle fibres over time. The structure of the microfluidic chip on which the cells are cultured facilitates the observation of motor neuron axonal outgrowth as well as neuromuscular junction formation and maturation.
iPSC-derived motor neurons were modified to be controlled using optogenetics, which enables precise manipulation of their activity and phenotype as well as consequent muscle contraction when stimulated with light. By using this technique, Dr. Kamm and his team have provided a dynamic in vitro model to study disease conditions and potential treatments, permitting muscle force measurements and observations of cell behaviour. Additionally, optional immunostaining and PCR experiments can help characterize differentiation and functionality. This versatile protocol, although initially demonstrated using iPSCs from ALS patients, holds the potential for improving our understanding of the pathogenesis of a wide variety NMDs using patient-specific cells.
Advancing Drug Discovery and Precision Medicine
Traditional drug discovery methods for MNDs have often disregarded the role of skeletal muscle cells, focusing predominantly on their effect on motor neurons. However, the new 3D neuromuscular model by Dr. Kamm and colleagues offers a broader view of the pathology affecting the NMJ and cell-cell interactions. Dr. Kamm’s approach presents a novel avenue for uncovering effective treatments targeting both motor neurons and muscle cells, that address the complex nature of MNDs.
The use of patient-specific iPSCs in this model holds great promise for personalized medicine. Tailoring treatments to an individual’s genetics and consequent drug response can enhance their effectiveness while minimising side effects. By providing a more accurate representation of the disease, the 3D neuromuscular model could accelerate drug discovery and streamline the transition from laboratory research to clinical applications.
Future Directions
The progress in in vitro modelling made by Dr. Kamm and his colleagues paves the way for groundbreaking advancements in the field of MND research. The model’s capacity to mimic the complex interactions between motor neurons and skeletal muscle cells brings researchers closer to unlocking novel therapeutic strategies and ultimately improving the lives of patients battling these devastating conditions.
CELLBANKER 1 and STEM-CELLBANKER are available from AMSBIO in serum, serum-free, DMSO-free, and GMP-grade formats, for fast and reliable cryopreservation of any cell type. The CELLBANKER series provides stable long-term cryopreservation for up to 8 years, with consistently high post-thaw cell viability (>90%).
For customisable microfluidic 3D drug screening services, discover how ScreenIn3D can advance your drug discovery. ScreenIn3D provide high-throughput and high-quality screening services that help validate the effectiveness of compounds and treatment on physiologically relevant, preclinical in vitro models of disease.
NMD – neuromuscular disease
MND – motor neuron disease
ALS – amyotrophic lateral sclerosis
iPSC – induced pluripotent stem cell
NMJ – neuromuscular junction
MND – motor neuron disease
ALS – amyotrophic lateral sclerosis
iPSC – induced pluripotent stem cell
NMJ – neuromuscular junction
Further Reading
Osaki, T., Uzel, S.G.M. & Kamm, R.D. On-chip 3D neuromuscular model for drug screening and precision medicine in neuromuscular disease. Nat Protoc 15, 421–449 (2020). https://doi.org/10.1038/s41596-019-0248-1
