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Inhibition of peripheral macrophages by nicotinic acetylcholine receptor agonists suppresses spinal microglial activation and neuropathic pain in mice with peripheral nerve injury

BACKGROUND: Neuro–immune interaction underlies chronic neuroinflammation and aberrant sensory processing resulting in neuropathic pain. Despite the pathological significance of both neuroinflammation-driven peripheral sensitization and spinal sensitization, the functional relationship between these...

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Autores principales: Kiguchi, Norikazu, Kobayashi, Daichi, Saika, Fumihiro, Matsuzaki, Shinsuke, Kishioka, Shiroh
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5872578/
https://www.ncbi.nlm.nih.gov/pubmed/29587798
http://dx.doi.org/10.1186/s12974-018-1133-5
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author Kiguchi, Norikazu
Kobayashi, Daichi
Saika, Fumihiro
Matsuzaki, Shinsuke
Kishioka, Shiroh
author_facet Kiguchi, Norikazu
Kobayashi, Daichi
Saika, Fumihiro
Matsuzaki, Shinsuke
Kishioka, Shiroh
author_sort Kiguchi, Norikazu
collection PubMed
description BACKGROUND: Neuro–immune interaction underlies chronic neuroinflammation and aberrant sensory processing resulting in neuropathic pain. Despite the pathological significance of both neuroinflammation-driven peripheral sensitization and spinal sensitization, the functional relationship between these two distinct events has not been understood. METHODS: In this study, we determined whether inhibition of inflammatory macrophages by administration of α4β2 nicotinic acetylcholine receptor (nAChR) agonists improves neuropathic pain and affects microglial activation in the spinal dorsal horn (SDH) in mice following partial sciatic nerve ligation (PSL). Expression levels of neuroinflammatory molecules were evaluated by RT-qPCR and immunohistochemistry, and PSL-induced mechanical allodynia was defined by the von Frey test. RESULTS: Flow cytometry revealed that CD11b(+) F4/80(+) macrophages were accumulated in the injured sciatic nerve (SCN) after PSL. TC-2559, a full agonist for α4β2 nAChR, suppressed the upregulation of interleukin-1β (IL-1β) in the injured SCN after PSL and attenuated lipopolysaccharide-induced upregulation of IL-1β in cultured macrophages. Systemic (subcutaneous, s.c.) administration of TC-2559 during either the early (days 0–3) or middle/late (days 7–10) phase of PSL improved mechanical allodynia. Moreover, local (perineural, p.n.) administration of TC-2559 and sazetidine A, a partial agonist for α4β2 nAChR, during either the early or middle phase of PSL improved mechanical allodynia. However, p.n. administration of sazetidine A during the late (days 21–24) phase did not show the attenuating effect, whereas p.n. administration of TC-2559 during this phase relieved mechanical allodynia. Most importantly, p.n. administration of TC-2559 significantly suppressed morphological activation of Iba1(+) microglia and decreased the upregulation of inflammatory microglia-dominant molecules, such as CD68, interferon regulatory factor 5, and IL-1β in the SDH after PSL. CONCLUSION: These findings support the notion that pharmacological inhibition of inflammatory macrophages using an α4β2 nAChR agonist exhibit a wide therapeutic window on neuropathic pain after nerve injury, and it could be nominated as a novel pharmacotherapy to relieve intractable pain. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12974-018-1133-5) contains supplementary material, which is available to authorized users.
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spelling pubmed-58725782018-04-02 Inhibition of peripheral macrophages by nicotinic acetylcholine receptor agonists suppresses spinal microglial activation and neuropathic pain in mice with peripheral nerve injury Kiguchi, Norikazu Kobayashi, Daichi Saika, Fumihiro Matsuzaki, Shinsuke Kishioka, Shiroh J Neuroinflammation Research BACKGROUND: Neuro–immune interaction underlies chronic neuroinflammation and aberrant sensory processing resulting in neuropathic pain. Despite the pathological significance of both neuroinflammation-driven peripheral sensitization and spinal sensitization, the functional relationship between these two distinct events has not been understood. METHODS: In this study, we determined whether inhibition of inflammatory macrophages by administration of α4β2 nicotinic acetylcholine receptor (nAChR) agonists improves neuropathic pain and affects microglial activation in the spinal dorsal horn (SDH) in mice following partial sciatic nerve ligation (PSL). Expression levels of neuroinflammatory molecules were evaluated by RT-qPCR and immunohistochemistry, and PSL-induced mechanical allodynia was defined by the von Frey test. RESULTS: Flow cytometry revealed that CD11b(+) F4/80(+) macrophages were accumulated in the injured sciatic nerve (SCN) after PSL. TC-2559, a full agonist for α4β2 nAChR, suppressed the upregulation of interleukin-1β (IL-1β) in the injured SCN after PSL and attenuated lipopolysaccharide-induced upregulation of IL-1β in cultured macrophages. Systemic (subcutaneous, s.c.) administration of TC-2559 during either the early (days 0–3) or middle/late (days 7–10) phase of PSL improved mechanical allodynia. Moreover, local (perineural, p.n.) administration of TC-2559 and sazetidine A, a partial agonist for α4β2 nAChR, during either the early or middle phase of PSL improved mechanical allodynia. However, p.n. administration of sazetidine A during the late (days 21–24) phase did not show the attenuating effect, whereas p.n. administration of TC-2559 during this phase relieved mechanical allodynia. Most importantly, p.n. administration of TC-2559 significantly suppressed morphological activation of Iba1(+) microglia and decreased the upregulation of inflammatory microglia-dominant molecules, such as CD68, interferon regulatory factor 5, and IL-1β in the SDH after PSL. CONCLUSION: These findings support the notion that pharmacological inhibition of inflammatory macrophages using an α4β2 nAChR agonist exhibit a wide therapeutic window on neuropathic pain after nerve injury, and it could be nominated as a novel pharmacotherapy to relieve intractable pain. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12974-018-1133-5) contains supplementary material, which is available to authorized users. BioMed Central 2018-03-27 /pmc/articles/PMC5872578/ /pubmed/29587798 http://dx.doi.org/10.1186/s12974-018-1133-5 Text en © The Author(s). 2018 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Kiguchi, Norikazu
Kobayashi, Daichi
Saika, Fumihiro
Matsuzaki, Shinsuke
Kishioka, Shiroh
Inhibition of peripheral macrophages by nicotinic acetylcholine receptor agonists suppresses spinal microglial activation and neuropathic pain in mice with peripheral nerve injury
title Inhibition of peripheral macrophages by nicotinic acetylcholine receptor agonists suppresses spinal microglial activation and neuropathic pain in mice with peripheral nerve injury
title_full Inhibition of peripheral macrophages by nicotinic acetylcholine receptor agonists suppresses spinal microglial activation and neuropathic pain in mice with peripheral nerve injury
title_fullStr Inhibition of peripheral macrophages by nicotinic acetylcholine receptor agonists suppresses spinal microglial activation and neuropathic pain in mice with peripheral nerve injury
title_full_unstemmed Inhibition of peripheral macrophages by nicotinic acetylcholine receptor agonists suppresses spinal microglial activation and neuropathic pain in mice with peripheral nerve injury
title_short Inhibition of peripheral macrophages by nicotinic acetylcholine receptor agonists suppresses spinal microglial activation and neuropathic pain in mice with peripheral nerve injury
title_sort inhibition of peripheral macrophages by nicotinic acetylcholine receptor agonists suppresses spinal microglial activation and neuropathic pain in mice with peripheral nerve injury
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5872578/
https://www.ncbi.nlm.nih.gov/pubmed/29587798
http://dx.doi.org/10.1186/s12974-018-1133-5
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