Biphalin, a Dimeric Enkephalin, Alleviates LPS-Induced Activation in Rat Primary Microglial Cultures in Opioid Receptor-Dependent and Receptor-Independent Manners

Neuropathic pain is relatively less responsive to opioids than other types of pain, which is possibly due to a disrupted opioid system partially caused by the profound microglial cell activation that underlines neuroinflammation. We demonstrated that intrathecally injected biphalin, a dimeric enkeph...

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Main Authors: Katarzyna Popiolek-Barczyk, Anna Piotrowska, Wioletta Makuch, Joanna Mika
Format: Article
Language:English
Published: Wiley 2017-01-01
Series:Neural Plasticity
Online Access:http://dx.doi.org/10.1155/2017/3829472
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author Katarzyna Popiolek-Barczyk
Anna Piotrowska
Wioletta Makuch
Joanna Mika
author_facet Katarzyna Popiolek-Barczyk
Anna Piotrowska
Wioletta Makuch
Joanna Mika
author_sort Katarzyna Popiolek-Barczyk
collection DOAJ
description Neuropathic pain is relatively less responsive to opioids than other types of pain, which is possibly due to a disrupted opioid system partially caused by the profound microglial cell activation that underlines neuroinflammation. We demonstrated that intrathecally injected biphalin, a dimeric enkephalin analog, diminished symptoms of neuropathy in a preclinical model of neuropathic pain in rats (CCI, chronic constriction injury of the sciatic nerve) at day 12 postinjury. Using primary microglial cell cultures, we revealed that biphalin did not influence cell viability but diminished NO production and expression of Iba1 in LPS-stimulated cells. Biphalin also diminished MOP receptor level, as well as pronociceptive mediators (iNOS, IL-1β, and IL-18) in an opioid receptor-dependent manner, and it was correlated with diminished p-NF-κB, p-IκB, p-p38MAPK, and TRIF levels. Biphalin reduced IL-6, IL-10, TNFα, p-STAT3, and p-ERK1/2 and upregulated SOCS3, TLR4, and MyD88; however, this effect was not reversed by naloxone pretreatment. Our study provides evidence that biphalin diminishes neuropathy symptoms, which might be partially related to reduced pronociceptive mediators released by activated microglia. Biphalin may be a putative drug for future pain therapy, especially for the treatment of neuropathic pain, when the lower analgesic effects of morphine are correlated with profound microglial cell activation.
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spelling doaj-art-c0648833d6194d9c894d78109791b5842025-02-03T06:00:16ZengWileyNeural Plasticity2090-59041687-54432017-01-01201710.1155/2017/38294723829472Biphalin, a Dimeric Enkephalin, Alleviates LPS-Induced Activation in Rat Primary Microglial Cultures in Opioid Receptor-Dependent and Receptor-Independent MannersKatarzyna Popiolek-Barczyk0Anna Piotrowska1Wioletta Makuch2Joanna Mika3Department of Pain Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, PolandDepartment of Pain Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, PolandDepartment of Pain Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, PolandDepartment of Pain Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, PolandNeuropathic pain is relatively less responsive to opioids than other types of pain, which is possibly due to a disrupted opioid system partially caused by the profound microglial cell activation that underlines neuroinflammation. We demonstrated that intrathecally injected biphalin, a dimeric enkephalin analog, diminished symptoms of neuropathy in a preclinical model of neuropathic pain in rats (CCI, chronic constriction injury of the sciatic nerve) at day 12 postinjury. Using primary microglial cell cultures, we revealed that biphalin did not influence cell viability but diminished NO production and expression of Iba1 in LPS-stimulated cells. Biphalin also diminished MOP receptor level, as well as pronociceptive mediators (iNOS, IL-1β, and IL-18) in an opioid receptor-dependent manner, and it was correlated with diminished p-NF-κB, p-IκB, p-p38MAPK, and TRIF levels. Biphalin reduced IL-6, IL-10, TNFα, p-STAT3, and p-ERK1/2 and upregulated SOCS3, TLR4, and MyD88; however, this effect was not reversed by naloxone pretreatment. Our study provides evidence that biphalin diminishes neuropathy symptoms, which might be partially related to reduced pronociceptive mediators released by activated microglia. Biphalin may be a putative drug for future pain therapy, especially for the treatment of neuropathic pain, when the lower analgesic effects of morphine are correlated with profound microglial cell activation.http://dx.doi.org/10.1155/2017/3829472
spellingShingle Katarzyna Popiolek-Barczyk
Anna Piotrowska
Wioletta Makuch
Joanna Mika
Biphalin, a Dimeric Enkephalin, Alleviates LPS-Induced Activation in Rat Primary Microglial Cultures in Opioid Receptor-Dependent and Receptor-Independent Manners
Neural Plasticity
title Biphalin, a Dimeric Enkephalin, Alleviates LPS-Induced Activation in Rat Primary Microglial Cultures in Opioid Receptor-Dependent and Receptor-Independent Manners
title_full Biphalin, a Dimeric Enkephalin, Alleviates LPS-Induced Activation in Rat Primary Microglial Cultures in Opioid Receptor-Dependent and Receptor-Independent Manners
title_fullStr Biphalin, a Dimeric Enkephalin, Alleviates LPS-Induced Activation in Rat Primary Microglial Cultures in Opioid Receptor-Dependent and Receptor-Independent Manners
title_full_unstemmed Biphalin, a Dimeric Enkephalin, Alleviates LPS-Induced Activation in Rat Primary Microglial Cultures in Opioid Receptor-Dependent and Receptor-Independent Manners
title_short Biphalin, a Dimeric Enkephalin, Alleviates LPS-Induced Activation in Rat Primary Microglial Cultures in Opioid Receptor-Dependent and Receptor-Independent Manners
title_sort biphalin a dimeric enkephalin alleviates lps induced activation in rat primary microglial cultures in opioid receptor dependent and receptor independent manners
url http://dx.doi.org/10.1155/2017/3829472
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