Investigation of early axonal phenotypes in an iPSC-derived ALS cellular model using a microfluidic device

Area of Science:

• Neuroscience
• Stem Cell Biology
• Biomedical Engineering

Background:

• Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease impacting motor neurons.
• Mutations in the FUS/TLS gene are a common cause of familial ALS.
• Induced pluripotent stem cells (iPSCs) from ALS patients are valuable for studying neurodegeneration.

Purpose of the Study:

• To develop and validate a microfluidic device for high-resolution observation of axonal phenotypes in iPSC-derived neurons.
• To evaluate neurodegenerative phenotypes in lower motor neurons (LMNs) with FUS/TLS mutations using the microfluidic system.
• To identify early cellular markers of degeneration in ALS.

Main Methods:

• Generation of lower motor neurons (LMNs) from iPSCs carrying FUS/TLS mutations (FUS_H517D).
• Utilizing a novel microfluidic device for culturing and observing neuronal axonal growth, morphology, and trafficking.
• Assessing cell viability, axonal length, and mitochondrial transport under varying conditions.

Main Results:

• FUS-mutated LMNs exhibited significantly reduced axonal length and impaired axonal growth by DIV7, preceding overt cell death.
• Cell viability of FUS-mutated LMNs decreased notably between DIV14 and DIV21 compared to controls.
• Increased motile mitochondria and altered trafficking patterns were observed in FUS-mutated LMN axons.

Conclusions:

• The microfluidic device effectively models early axonal degeneration in ALS.
• Axonal growth restriction and mitochondrial transport alterations are early detectable phenotypes in FUS-mutated neurons.
• This system provides a valuable cellular model for investigating the molecular mechanisms of axonal degeneration in ALS.