Stimulation of synapse formation between stem cell-derived neurons and native brainstem auditory neurons

Area of Science:

• Neuroscience
• Stem Cell Biology
• Regenerative Medicine

Background:

• Integrating stem cell-derived cells into native environments is a significant challenge.
• Understanding peripheral nervous system (PNS) and central nervous system (CNS) neuronal interactions is crucial for neural repair.

Purpose of the Study:

• To investigate the potential for stem cell-derived peripheral neurons to synapse with central nervous system neurons.
• To explore methods for co-culturing neural stem cell-derived spiral ganglion-like neurons (ScNs) with mouse auditory cochlear nucleus (CN) neurons.

Main Methods:

• Co-culturing ScNs (from EGFP-labeled neural stem cells) with mouse CN neurons for 4-6 days.
• Utilizing astrocyte-conditioned medium (ACM) to assess its effect on synaptogenesis.
• Employing immunofluorescence, immunodepletion, and knockout studies to identify synaptic markers and key molecules like thrombospondin-1.

Main Results:

• Class III β-tubulin (TUJ1)-expressing connections formed between ScNs and CN neurons.
• Astrocyte-conditioned medium significantly increased synaptic vesicle marker SV2 expression.
• Thrombospondin-1 was identified as a key mediator of ACM-induced synaptogenesis.
• Functional synapse-like structures expressing glutamatergic markers (VGluT1) and pre/post-synaptic proteins were observed, with evidence of synaptic vesicle recycling.

Conclusions:

• Stem cell-derived PNS neurons can establish functional synaptic connections with native CNS neurons.
• This finding is critical for advancing stem cell-based strategies for neural pathway regeneration.
• Thrombospondin-1 plays a vital role in facilitating these inter-neuronal connections.