Limits...
Robust Type-specific Hemisynapses Induced by Artificial Dendrites.

Kim EJ, Jeon CS, Lee SY, Hwang I, Chung TD - Sci Rep (2016)

Bottom Line: To lay a foundation of synapse-based neural interfaces, artificial dendrites are generated by covering abiotic substrata with ectodomains of type-specific synaptogenic proteins that are C-terminally tagged with biotinylated fluorescent proteins.By contrast, if the artificial dendrites are applied to the axonal components of micropatterned neurons, correctly-matched synaptic specificity emerges regardless of the neuronal developmental stages.The hemisynapses retain their initially established type-specificity during neuronal development and maintain their synaptic strength provided live neurons, implying the possibility of durable synapse-based biointerfaces.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Seoul National University, Seoul, 08826, Korea.

ABSTRACT
Type-specificity of synapses, excitatory and inhibitory, regulates information process in neural networks via chemical neurotransmitters. To lay a foundation of synapse-based neural interfaces, artificial dendrites are generated by covering abiotic substrata with ectodomains of type-specific synaptogenic proteins that are C-terminally tagged with biotinylated fluorescent proteins. The excitatory artificial synapses displaying engineered ectodomains of postsynaptic neuroligin-1 (NL1) induce the formation of excitatory presynapses with mixed culture of neurons in various developmental stages, while the inhibitory artificial dendrites displaying engineered NL2 and Slitrk3 induce inhibitory presynapses only with mature neurons. By contrast, if the artificial dendrites are applied to the axonal components of micropatterned neurons, correctly-matched synaptic specificity emerges regardless of the neuronal developmental stages. The hemisynapses retain their initially established type-specificity during neuronal development and maintain their synaptic strength provided live neurons, implying the possibility of durable synapse-based biointerfaces.

No MeSH data available.


NL2-R and SL3-R induce the formation of inhibitory hemisynapses only with mature neurons.The NL2-R and SL3-R beads were seeded and analysed for the synaptogenesis as in the case of NL1-R. (a–g) ICC images for NL2-R-induced hemisynapses are aligned on upper lines. (a–d) Only excitatory presynaptic differentiations appeared during the early neuronal development stages, which lasted until DIV15. Correctly matched synapses began to appear on DIV9 when the glutamatergic specificity is still dominant (e). The fully inhibitory hemisynapses could be formed only when the artificial dendritic beads are in contact with mature neurons (DIV14) (g). ∗∗p < 0.01; others, p < 0.001 between the same marker proteins of NL2-R and SL3-R.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4829863&req=5

f4: NL2-R and SL3-R induce the formation of inhibitory hemisynapses only with mature neurons.The NL2-R and SL3-R beads were seeded and analysed for the synaptogenesis as in the case of NL1-R. (a–g) ICC images for NL2-R-induced hemisynapses are aligned on upper lines. (a–d) Only excitatory presynaptic differentiations appeared during the early neuronal development stages, which lasted until DIV15. Correctly matched synapses began to appear on DIV9 when the glutamatergic specificity is still dominant (e). The fully inhibitory hemisynapses could be formed only when the artificial dendritic beads are in contact with mature neurons (DIV14) (g). ∗∗p < 0.01; others, p < 0.001 between the same marker proteins of NL2-R and SL3-R.

Mentions: We next applied the NL2-R- and SL3-R-coated inhibitory artificial dendrites on neuron cultures in various developmental stages to compare the timing of the instruction of inhibitory hemisynapses. When we added NL2-R or SL3-R beads to immature neuronal cells (DIV0 and 7), we could observe only excitatory presynaptic differentiation regardless of the coculture duration (Figs 4a–d and S3a–d,h–k). The inhibitory synaptic specificity appeared when the coculture started on DIV9 and was fully restored on DIV14 (Figs 4e–g and S3e–g,l–n). Thus, it was the timing of the encounter with artificial dendrites that determined the inverted synaptic specificity of growing neurons.


Robust Type-specific Hemisynapses Induced by Artificial Dendrites.

Kim EJ, Jeon CS, Lee SY, Hwang I, Chung TD - Sci Rep (2016)

NL2-R and SL3-R induce the formation of inhibitory hemisynapses only with mature neurons.The NL2-R and SL3-R beads were seeded and analysed for the synaptogenesis as in the case of NL1-R. (a–g) ICC images for NL2-R-induced hemisynapses are aligned on upper lines. (a–d) Only excitatory presynaptic differentiations appeared during the early neuronal development stages, which lasted until DIV15. Correctly matched synapses began to appear on DIV9 when the glutamatergic specificity is still dominant (e). The fully inhibitory hemisynapses could be formed only when the artificial dendritic beads are in contact with mature neurons (DIV14) (g). ∗∗p < 0.01; others, p < 0.001 between the same marker proteins of NL2-R and SL3-R.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4829863&req=5

f4: NL2-R and SL3-R induce the formation of inhibitory hemisynapses only with mature neurons.The NL2-R and SL3-R beads were seeded and analysed for the synaptogenesis as in the case of NL1-R. (a–g) ICC images for NL2-R-induced hemisynapses are aligned on upper lines. (a–d) Only excitatory presynaptic differentiations appeared during the early neuronal development stages, which lasted until DIV15. Correctly matched synapses began to appear on DIV9 when the glutamatergic specificity is still dominant (e). The fully inhibitory hemisynapses could be formed only when the artificial dendritic beads are in contact with mature neurons (DIV14) (g). ∗∗p < 0.01; others, p < 0.001 between the same marker proteins of NL2-R and SL3-R.
Mentions: We next applied the NL2-R- and SL3-R-coated inhibitory artificial dendrites on neuron cultures in various developmental stages to compare the timing of the instruction of inhibitory hemisynapses. When we added NL2-R or SL3-R beads to immature neuronal cells (DIV0 and 7), we could observe only excitatory presynaptic differentiation regardless of the coculture duration (Figs 4a–d and S3a–d,h–k). The inhibitory synaptic specificity appeared when the coculture started on DIV9 and was fully restored on DIV14 (Figs 4e–g and S3e–g,l–n). Thus, it was the timing of the encounter with artificial dendrites that determined the inverted synaptic specificity of growing neurons.

Bottom Line: To lay a foundation of synapse-based neural interfaces, artificial dendrites are generated by covering abiotic substrata with ectodomains of type-specific synaptogenic proteins that are C-terminally tagged with biotinylated fluorescent proteins.By contrast, if the artificial dendrites are applied to the axonal components of micropatterned neurons, correctly-matched synaptic specificity emerges regardless of the neuronal developmental stages.The hemisynapses retain their initially established type-specificity during neuronal development and maintain their synaptic strength provided live neurons, implying the possibility of durable synapse-based biointerfaces.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Seoul National University, Seoul, 08826, Korea.

ABSTRACT
Type-specificity of synapses, excitatory and inhibitory, regulates information process in neural networks via chemical neurotransmitters. To lay a foundation of synapse-based neural interfaces, artificial dendrites are generated by covering abiotic substrata with ectodomains of type-specific synaptogenic proteins that are C-terminally tagged with biotinylated fluorescent proteins. The excitatory artificial synapses displaying engineered ectodomains of postsynaptic neuroligin-1 (NL1) induce the formation of excitatory presynapses with mixed culture of neurons in various developmental stages, while the inhibitory artificial dendrites displaying engineered NL2 and Slitrk3 induce inhibitory presynapses only with mature neurons. By contrast, if the artificial dendrites are applied to the axonal components of micropatterned neurons, correctly-matched synaptic specificity emerges regardless of the neuronal developmental stages. The hemisynapses retain their initially established type-specificity during neuronal development and maintain their synaptic strength provided live neurons, implying the possibility of durable synapse-based biointerfaces.

No MeSH data available.