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Capsaicin-induced endocytosis of endogenous presynaptic Ca_{V}2.2 in DRG-spinal cord co-cultures inhibits presynaptic function

Ramgoolam, Krishma H; Dolphin, Annette C; (2023) Capsaicin-induced endocytosis of endogenous presynaptic Ca_{V}2.2 in DRG-spinal cord co-cultures inhibits presynaptic function. Function , 4 (1) , Article zqac058. 10.1093/function/zqac058. Green open access

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Abstract

The N-type calcium channel, CaV2.2 is key to neurotransmission from the primary afferent terminals of dorsal root ganglion (DRG) neurons to their post-synaptic targets in the spinal cord. In this study we have utilized CaV2.2_HA knock-in mice, because the exofacial epitope tag in CaV2.2_HA enables accurate detection and localization of endogenous CaV2.2. CaV2.2_HA knock-in mice were used as a source of DRGs to exclusively study the presynaptic expression of N-type calcium channels in co-cultures between DRG neurons and wild-type spinal cord neurons. CaV2.2_HA is strongly expressed on the cell surface, particularly in TRPV1-positive small and medium DRG neurons. Super-resolution images of the presynaptic terminals revealed an increase in CaV2.2_HA expression and increased association with the post-synaptic marker Homer over time in vitro. Brief application of the TRPV1 agonist, capsaicin, resulted in a significant down-regulation of cell surface CaV2.2_HA expression in DRG neuron somata. At their presynaptic terminals, capsaicin caused a reduction in CaV2.2_HA proximity to and co-localization with the active zone marker RIM 1/2, as well as a lower contribution of N-type channels to single action potential-mediated Ca2+ influx. The mechanism of this down-regulation of CaV2.2_HA involves a Rab 11a-dependent trafficking process, since dominant-negative Rab11a(S25N) occludes the effect of capsaicin on presynaptic CaV2.2_HA expression, and also prevents the effect of capsaicin on action potential induced Ca2+ influx. Taken together, these data suggest that capsaicin causes a decrease in cell surface CaV2.2_HA expression in DRG terminals via a Rab11a-dependent endosomal trafficking pathway.

Type: Article
Title: Capsaicin-induced endocytosis of endogenous presynaptic Ca_{V}2.2 in DRG-spinal cord co-cultures inhibits presynaptic function
Open access status: An open access version is available from UCL Discovery
DOI: 10.1093/function/zqac058
Publisher version: https://doi.org/10.1093/function/zqac058
Language: English
Additional information: Copyright The Author(s) 2022. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
Keywords: CaV2.2 channels, calcium imaging, DRG neurons, TRPV1 channels, protein trafficking, rab11, capsaicin
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences > Neuro, Physiology and Pharmacology
URI: https://discovery.ucl.ac.uk/id/eprint/10161663
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