Detecting MUNC18-1 related presynaptic dysfunction and rescue in human iPSC-derived neurons

Area of Science:

• Neuroscience
• Stem Cell Biology
• Genetics

Background:

• Human induced pluripotent stem cell (hiPSC)-derived neurons are valuable for disease modeling in drug development.
• Syntaxin binding protein 1 (STXBP1) encodes MUNC18-1, a protein crucial for synaptic vesicle function.
• STXBP1 mutations are linked to neurodevelopmental disorders.

Purpose of the Study:

• To characterize neurophysiological phenotypes in NGN2-differentiated hiPSC neurons lacking STXBP1.
• To assess the rescue of synaptic dysfunction by STXBP1 reconstitution.
• To validate a suite of neurophysiological tools for studying synaptic transmission.

Main Methods:

• Utilized multielectrode array (MEA) and calcium imaging to assess network activity.
• Measured miniature postsynaptic currents (mPSCs) to evaluate synaptic function.
• Quantified glutamate release into culture media.
• Employed adeno-associated virus (AAV) transduction for gene reconstitution.

Main Results:

• STXBP1 knockout NGN2 neurons exhibited a lack of mPSCs and disrupted network bursting.
• Presynaptic deficits were confirmed by reduced glutamate release in knockout neurons.
• AAV-mediated STXBP1 reconstitution dose-dependently rescued the observed synaptic phenotypes.

Conclusions:

• STXBP1 is essential for normal presynaptic function in human iPSC-derived neurons.
• The characterized neurophysiological methods are effective for studying synaptic transmission.
• This model system provides a platform for investigating STXBP1-related disorders and therapeutic interventions.