Optogenetically controlled human functional motor endplate for testing botulinum neurotoxins

Area of Science:

• Neuroscience
• Stem Cell Biology
• Pharmacology

Background:

• Developing effective botulinum neurotoxin (BoNT) therapeutics is hindered by the lack of physiologically relevant and predictive cell-based assays.
• Human induced pluripotent stem cells (hiPSCs) offer a promising avenue to create more relevant cellular models for preclinical drug development.

Purpose of the Study:

• To investigate the potential of using hiPSC-derived motor neurons (hMNs) combined with optogenetics and calcium imaging to create a sensitive in vitro model for BoNT testing.
• To assess the sensitivity of a human muscle-nerve coculture system to BoNT intoxication.

Main Methods:

• Developed a functional muscle-nerve coculture system using hMNs and human immortalized skeletal muscle cells.
• Utilized optogenetic optical stimulation of hMNs and calcium imaging to monitor muscle cell activity.
• Assessed dose-dependent sensitivity to BoNT intoxication in the developed in vitro model.

Main Results:

• hMNs successfully innervated myotubes, inducing contractions and calcium transients in muscle cells, forming a functional human motor endplate.
• The in vitro model demonstrated dose-dependent sensitivity to BoNT intoxication.
• Optogenetics combined with calcium imaging effectively monitored the impact of BoNTs on synaptic transmission.

Conclusions:

• The optogenetically controlled hiPSC-derived muscle-nerve system shows significant promise for pharmaceutical testing and development of BoNT therapeutics.
• This novel model enhances the translational value of preclinical data for BoNT drug development.