Cargando…

Axonal Kainate Receptors Modulate the Strength of Efferent Connectivity by Regulating Presynaptic Differentiation

Kainate type of glutamate receptors (KARs) are highly expressed during early brain development and may influence refinement of the circuitry, via modulating synaptic transmission and plasticity. KARs are also localized to axons, however, their exact roles in regulating presynaptic processes remain c...

Descripción completa

Detalles Bibliográficos
Autores principales: Sakha, Prasanna, Vesikansa, Aino, Orav, Ester, Heikkinen, Joonas, Kukko-Lukjanov, Tiina-Kaisa, Shintyapina, Alexandra, Franssila, Sami, Jokinen, Ville, Huttunen, Henri J., Lauri, Sari E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4720004/
https://www.ncbi.nlm.nih.gov/pubmed/26834558
http://dx.doi.org/10.3389/fncel.2016.00003
_version_ 1782411022075691008
author Sakha, Prasanna
Vesikansa, Aino
Orav, Ester
Heikkinen, Joonas
Kukko-Lukjanov, Tiina-Kaisa
Shintyapina, Alexandra
Franssila, Sami
Jokinen, Ville
Huttunen, Henri J.
Lauri, Sari E.
author_facet Sakha, Prasanna
Vesikansa, Aino
Orav, Ester
Heikkinen, Joonas
Kukko-Lukjanov, Tiina-Kaisa
Shintyapina, Alexandra
Franssila, Sami
Jokinen, Ville
Huttunen, Henri J.
Lauri, Sari E.
author_sort Sakha, Prasanna
collection PubMed
description Kainate type of glutamate receptors (KARs) are highly expressed during early brain development and may influence refinement of the circuitry, via modulating synaptic transmission and plasticity. KARs are also localized to axons, however, their exact roles in regulating presynaptic processes remain controversial. Here, we have used a microfluidic chamber system allowing specific manipulation of KARs in presynaptic neurons to study their functions in synaptic development and function in vitro. Silencing expression of endogenous KARs resulted in lower density of synaptophysin immunopositive puncta in microfluidically isolated axons. Various recombinant KAR subunits and pharmacological compounds were used to dissect the mechanisms behind this effect. The calcium permeable (Q) variants of the low-affinity (GluK1–3) subunits robustly increased synaptophysin puncta in axons in a manner that was dependent on receptor activity and PKA and PKC dependent signaling. Further, an associated increase in the mean active zone length was observed in electron micrographs. Selective presynaptic expression of these subunits resulted in higher success rate of evoked EPSCs consistent with higher probability of glutamate release. In contrast, the calcium-impermeable (R) variant of GluK1 or the high-affinity subunits (GluK4,5) had no effect on synaptic density or transmission efficacy. These data suggest that calcium permeable axonal KARs promote efferent connectivity by increasing the density of functional presynaptic release sites.
format Online
Article
Text
id pubmed-4720004
institution National Center for Biotechnology Information
language English
publishDate 2016
publisher Frontiers Media S.A.
record_format MEDLINE/PubMed
spelling pubmed-47200042016-01-29 Axonal Kainate Receptors Modulate the Strength of Efferent Connectivity by Regulating Presynaptic Differentiation Sakha, Prasanna Vesikansa, Aino Orav, Ester Heikkinen, Joonas Kukko-Lukjanov, Tiina-Kaisa Shintyapina, Alexandra Franssila, Sami Jokinen, Ville Huttunen, Henri J. Lauri, Sari E. Front Cell Neurosci Neuroscience Kainate type of glutamate receptors (KARs) are highly expressed during early brain development and may influence refinement of the circuitry, via modulating synaptic transmission and plasticity. KARs are also localized to axons, however, their exact roles in regulating presynaptic processes remain controversial. Here, we have used a microfluidic chamber system allowing specific manipulation of KARs in presynaptic neurons to study their functions in synaptic development and function in vitro. Silencing expression of endogenous KARs resulted in lower density of synaptophysin immunopositive puncta in microfluidically isolated axons. Various recombinant KAR subunits and pharmacological compounds were used to dissect the mechanisms behind this effect. The calcium permeable (Q) variants of the low-affinity (GluK1–3) subunits robustly increased synaptophysin puncta in axons in a manner that was dependent on receptor activity and PKA and PKC dependent signaling. Further, an associated increase in the mean active zone length was observed in electron micrographs. Selective presynaptic expression of these subunits resulted in higher success rate of evoked EPSCs consistent with higher probability of glutamate release. In contrast, the calcium-impermeable (R) variant of GluK1 or the high-affinity subunits (GluK4,5) had no effect on synaptic density or transmission efficacy. These data suggest that calcium permeable axonal KARs promote efferent connectivity by increasing the density of functional presynaptic release sites. Frontiers Media S.A. 2016-01-20 /pmc/articles/PMC4720004/ /pubmed/26834558 http://dx.doi.org/10.3389/fncel.2016.00003 Text en Copyright © 2016 Sakha, Vesikansa, Orav, Heikkinen, Kukko-Lukjanov, Shintyapina, Franssila, Jokinen, Huttunen and Lauri. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Neuroscience
Sakha, Prasanna
Vesikansa, Aino
Orav, Ester
Heikkinen, Joonas
Kukko-Lukjanov, Tiina-Kaisa
Shintyapina, Alexandra
Franssila, Sami
Jokinen, Ville
Huttunen, Henri J.
Lauri, Sari E.
Axonal Kainate Receptors Modulate the Strength of Efferent Connectivity by Regulating Presynaptic Differentiation
title Axonal Kainate Receptors Modulate the Strength of Efferent Connectivity by Regulating Presynaptic Differentiation
title_full Axonal Kainate Receptors Modulate the Strength of Efferent Connectivity by Regulating Presynaptic Differentiation
title_fullStr Axonal Kainate Receptors Modulate the Strength of Efferent Connectivity by Regulating Presynaptic Differentiation
title_full_unstemmed Axonal Kainate Receptors Modulate the Strength of Efferent Connectivity by Regulating Presynaptic Differentiation
title_short Axonal Kainate Receptors Modulate the Strength of Efferent Connectivity by Regulating Presynaptic Differentiation
title_sort axonal kainate receptors modulate the strength of efferent connectivity by regulating presynaptic differentiation
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4720004/
https://www.ncbi.nlm.nih.gov/pubmed/26834558
http://dx.doi.org/10.3389/fncel.2016.00003
work_keys_str_mv AT sakhaprasanna axonalkainatereceptorsmodulatethestrengthofefferentconnectivitybyregulatingpresynapticdifferentiation
AT vesikansaaino axonalkainatereceptorsmodulatethestrengthofefferentconnectivitybyregulatingpresynapticdifferentiation
AT oravester axonalkainatereceptorsmodulatethestrengthofefferentconnectivitybyregulatingpresynapticdifferentiation
AT heikkinenjoonas axonalkainatereceptorsmodulatethestrengthofefferentconnectivitybyregulatingpresynapticdifferentiation
AT kukkolukjanovtiinakaisa axonalkainatereceptorsmodulatethestrengthofefferentconnectivitybyregulatingpresynapticdifferentiation
AT shintyapinaalexandra axonalkainatereceptorsmodulatethestrengthofefferentconnectivitybyregulatingpresynapticdifferentiation
AT franssilasami axonalkainatereceptorsmodulatethestrengthofefferentconnectivitybyregulatingpresynapticdifferentiation
AT jokinenville axonalkainatereceptorsmodulatethestrengthofefferentconnectivitybyregulatingpresynapticdifferentiation
AT huttunenhenrij axonalkainatereceptorsmodulatethestrengthofefferentconnectivitybyregulatingpresynapticdifferentiation
AT laurisarie axonalkainatereceptorsmodulatethestrengthofefferentconnectivitybyregulatingpresynapticdifferentiation