Scalable, Optically-Responsive Human Neuromuscular Junction Model Reveals Convergent Mechanisms of Synaptic Dysfunction in Familial Amyotrophic Lateral Sclerosis

แนวคิดหลัก

A scalable, optically-responsive human neuromuscular junction model derived from pluripotent stem cells reveals common mechanisms of synaptic dysfunction across different familial ALS mutations, and demonstrates genotype-dependent therapeutic responses.

บทคัดย่อ

This study presents a new, highly reproducible and scalable in vitro model of human neuromuscular junctions (NMJs) derived from pluripotent stem cells (PSCs). The authors developed an optimized protocol to efficiently generate PSC-derived skeletal muscles and motor neurons, and co-culture them to spontaneously form functional NMJs within 5-7 days.
Key highlights:

The PSC-derived skeletal muscles and motor neurons display characteristic markers of maturity and spontaneous electrophysiological activity.
The co-culture system enables rapid and reproducible formation of functional NMJs, which can be optically stimulated and quantified using multi-electrode array recordings.
The model was used to assess NMJ dysfunction in three different familial ALS mutations (C9orf72 HRE, SOD1A5V, TDP43G298S) compared to isogenic controls.
All three ALS-affected NMJs showed significant reductions in the number of synapses formed and decreased electrophysiological activity compared to controls.
The electrophysiological deficits in C9orf72 HRE and TDP43G298S, but not SOD1A5V, were rescued by treatment with the neurotrophic factor GDNF.
This new PSC-derived NMJ platform provides a scalable and sensitive system to model NMJ pathology and test therapeutic interventions for ALS and other neuromuscular disorders.

สถิติ

The PSC-derived skeletal muscle cultures displayed nearly 100% expression of the muscle markers MHC and Desmin.
The PSC-derived motor neuron cultures contained over 90% HB9-positive cells.
The co-cultures of PSC-derived motor neurons and skeletal muscles showed a 1.5-2 fold reduction in the number of NMJs formed in ALS lines compared to controls.
The electrophysiological activity of the ALS-affected NMJs was significantly decreased compared to controls.
GDNF treatment rescued the electrophysiological deficits in C9orf72 HRE and TDP43G298S, but not SOD1A5V, NMJ co-cultures.

คำพูด

"Our newly developed method provides a platform for the systematic investigation of genetic causes of NMJ neurodegeneration and highlights the need for therapeutic avenues to consider patient genotype."
"The electrophysiological dysregulation observed in NMJ co-cultures of C9orf72 HRE and TDP-43G298S, but not in SOD1A5V, was rescued with GDNF, emphasizing the need for therapeutic studies that accounts for the patients' genotype."

ข้อมูลเชิงลึกที่สำคัญจาก

Scalable, optically-responsive human neuromuscular junction model reveals convergent mechanisms of synaptic dysfunction in familial ALS

by Chen,D., Phi... ที่ www.biorxiv.org 01-12-2024

https://www.biorxiv.org/content/10.1101/2024.01.11.575304v1

สอบถามเพิ่มเติม

How could this PSC-derived NMJ model be leveraged to investigate the role of non-neuronal cell types, such as glia or immune cells, in the pathogenesis of neuromuscular disorders?

The PSC-derived NMJ model provides a unique opportunity to investigate the role of non-neuronal cell types in neuromuscular disorders. By incorporating glial cells or immune cells into the co-culture system alongside PSC-derived motor neurons and skeletal muscles, researchers can study the complex interactions between different cell types at the NMJ. Glial cells, such as astrocytes and Schwann cells, play crucial roles in supporting and maintaining the function of motor neurons and skeletal muscles. By introducing glial cells into the co-culture system, researchers can assess their impact on NMJ formation, function, and pathology in neuromuscular disorders.
Similarly, immune cells, such as microglia, can also influence NMJ health and function. Inflammatory responses mediated by immune cells have been implicated in the pathogenesis of neuromuscular disorders. By including immune cells in the PSC-derived NMJ model, researchers can investigate the role of neuroinflammation in NMJ dysfunction and explore potential therapeutic targets to modulate immune responses in these disorders. Overall, the incorporation of non-neuronal cell types in the PSC-derived NMJ model can provide a more comprehensive understanding of the cellular interactions underlying neuromuscular disorders.

What other genetic or environmental factors, beyond the ALS mutations studied here, could be incorporated into this NMJ platform to model the complex etiology of neuromuscular diseases?

In addition to the ALS mutations studied in the PSC-derived NMJ model, various other genetic and environmental factors could be incorporated to model the complex etiology of neuromuscular diseases. Genetic factors such as mutations in genes associated with other neuromuscular disorders, including spinal muscular atrophy (SMA), Charcot-Marie-Tooth disease (CMT), and myasthenia gravis, could be introduced into the model to study their effects on NMJ function and pathology. By incorporating a diverse range of genetic mutations, researchers can investigate the specific mechanisms underlying different neuromuscular diseases and identify common pathways involved in NMJ dysfunction.
Furthermore, environmental factors known to influence neuromuscular disorders, such as exposure to toxins, viral infections, or metabolic disturbances, could also be integrated into the NMJ platform. By exposing the co-cultures to these environmental factors, researchers can simulate the complex interplay between genetic predisposition and environmental triggers in the development of neuromuscular diseases. This approach would allow for a more comprehensive understanding of the multifactorial nature of these disorders and provide insights into potential therapeutic interventions targeting both genetic and environmental contributors.

Given the genotype-dependent therapeutic responses observed with GDNF, how might this NMJ model be used to guide the development of personalized medicine approaches for neuromuscular disorders?

The genotype-dependent therapeutic responses observed with GDNF in the PSC-derived NMJ model highlight the potential for personalized medicine approaches in the treatment of neuromuscular disorders. By incorporating patient-specific iPSCs carrying different genetic mutations associated with neuromuscular diseases, researchers can evaluate the efficacy of various therapeutic interventions, such as GDNF treatment, in a genotype-specific manner. This personalized approach allows for the identification of targeted therapies that are most effective for individuals with specific genetic mutations, optimizing treatment outcomes and minimizing potential side effects.
Furthermore, the NMJ model can be used to screen a panel of potential therapeutic candidates, including small molecules, gene therapies, or growth factors, to identify the most effective treatment for each patient based on their genetic profile. By assessing the response of patient-specific NMJs to different treatments, clinicians can tailor therapeutic strategies to individual patients, leading to more personalized and effective interventions for neuromuscular disorders. Overall, the NMJ model provides a valuable platform for developing personalized medicine approaches that consider the genetic diversity and unique characteristics of each patient with neuromuscular diseases.