Potential of embryonic stem cell-derived neurons for synapse formation with auditory hair cells.
Recent studies have indicated that embryonic stem cells (ESCs) can be a source for the replacement of spiral ganglion neurons (SGNs), auditory primary neurons, and neurite projections from ESC-derived neurons to auditory sensory epithelia. However, the potential of ESC-derived neurons for synapse formation with auditory hair cells (HCs) has not been elucidated. The present study therefore aimed to examine the ability of ESC-derived neurons to form synaptic connections with HCs in vitro. Mouse ESC-derived neural progenitors expressing enhanced green fluorescence protein (EGFP) were cocultured with explants of cochlea sensory epithelia obtained from postnatal day 3 mice. After a 7-day culture, neurites of ESC-derived neurons predominantly elongated toward inner hair cells (IHCs), which play a crucial role in sound transmission to SGNs. Immunohistochemical analyses revealed the expression of synapsin 1 and synaptophysin in the nerve endings of ESC-derived neurons adjacent to IHCs, indicating the formation of synaptic connections. Transmission electron microscopy demonstrated synaptic contacts between nerve endings of ESC-derived neurons and IHCs. The present findings show that ESC-derived neurons can make synaptic connections with IHCs.
Department of Otolaryngology, Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Masahiro
M
Matsumoto
Takayuki
T
Nakagawa
Ken
K
Kojima
Tatsunori
T
Sakamoto
Fumino
F
Fujiyama
Juichi
J
Ito
D000818:Animals; D002450:Cell Communication / Q000502:physiology*; D018920:Coculture Techniques; D053595:Embryonic Stem Cells / Q000378:metabolism / Q000648:ultrastructure*; D006198:Hair Cells, Auditory / Q000648:ultrastructure*; D007150:Immunohistochemistry; D051379:Mice; D046529:Microscopy, Electron, Transmission; D009474:Neurons / Q000378:metabolism / Q000648:ultrastructure*; D013569:Synapses / Q000648:ultrastructure*; D016704:Synapsins / Q000096:biosynthesis; D016708:Synaptophysin / Q000096:biosynthesis
D016704:Synapsins; D016708:Synaptophysin