scholarly journals P2Y6 Receptor-Mediated Spinal Microglial Activation in Neuropathic Pain

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Jiang Bian ◽  
Ying Zhang ◽  
Yan Liu ◽  
Qun Li ◽  
Hai-bin Tang ◽  
...  

Objective. To explore the role of purine family member P2Y6 receptors in regulating neuropathic pain (NP) via neuroinflammation in the spinal cord. Methods. Chronic constriction injury of the sciatic nerve (CCI) of NP was classic in setting up models on Sprague-Dawley (SD) rats. Experiments were performed on rats with sham surgery, CCI, CCI + MRS2578 (a P2Y6 receptor antagonist), and UDP (a P2Y6 receptor agonist). The hyperalgesia intensity was mirrored by paw withdrawal threshold (PWT) and thermal withdrawal latency (TWL). Immunofluorescence staining and western blot were used to evaluate activated microglial marker Iba-1. Enzyme-linked immunosorbent assay (ELISA) was used to access levels of IL-6. Conventional reverse transcription polymerase chain reaction (RT-PCR) and western blot analysis were used to detect the expression of P2Y6 mRNA and activation of JAK/STAT signaling. Results. Among all groups, CCI caused decreased PWT and TWL compared to sham surgery, meaning a successful establishment of the NP model. These decreased values of PWT and TWL tests could be prevented by intraperitoneally injected MRS2578 and enhanced by UDP administration. Similarly, CCI induced increase of Iba-1 protein, P2Y6 mRNA expression, and circulating IL-6 secretion, as well as increased JAK2/STAT3 mRNA expression and phosphorylating modification in spinal cord tissues could also be diminished by MRS2578 treatment and exacerbated by UDP. Conclusions. These findings indicated the crucial role of the P2Y6 receptor in modulating the microglial and inflammatory responses in the process of NP in vivo. Results from this study would provide insights into targeting the P2Y6 receptor to treat NP in the near future.

Pharmacology ◽  
2019 ◽  
Vol 105 (3-4) ◽  
pp. 173-180 ◽  
Author(s):  
Yeo Ok Kim ◽  
Ji A Song ◽  
Woong Mo Kim ◽  
Myung Ha Yoon

Background: Chemotherapy-induced neuropathic pain (CINP) is a serious side effect of chemotherapy. Korean Red Ginseng (KRG) is a popular herbal medicine in Asian countries. We examined the therapeutic potential of intrathecally administered KRG for CINP and clarified the mechanisms of action with regard to 5-hydroxytryptamine (5-HT)7 receptor at the spinal level. Methods: CINP was evoked by intraperitoneal injection of cisplatin in male Sprague-Dawley rats. After examining the effects of intrathecally administered KRG on CINP, 5-HT receptor antagonist (dihydroergocristine [DHE]) was pretreated to determine the involvement of 5-HT receptor. In addition, intrathecal 5-HT7 receptor antagonist (SB269970) was administered to define the role of 5-HT7 receptor on the effect of KRG. 5-HT7 receptor mRNA expression levels and 5-HT concentrations were examined in the spinal cord. Results: Intrathecally administered KRG produced a limited, but a dose-dependent, antiallodynic effect. Intrathecally administered DHE antagonized the antiallodynia caused by KRG. Furthermore, intrathecal SB269970 also reversed the effect of KRG. No changes in 5-HT7 receptor mRNA expression were seen in the dorsal horn of the spinal cord after cisplatin injection. After injecting cisplatin, 5-HT levels were decreased in the spinal cord, whereas those of 5-HT were increased by intrathecal KRG. Conclusions: Intrathecally administered KRG decreased CINP. In addition, spinal 5-HT7 receptors contributed to the antiallodynic effect of KRG.


Author(s):  
Tatsuro Saruga ◽  
Tadaatsu Imaizumi ◽  
Shogo Kawaguchi ◽  
Kazuhiko Seya ◽  
Tomoh Matsumiya ◽  
...  

AbstractC-X-C motif chemokine 10 (CXCL10) is an inflammatory chemokine and a key molecule in the pathogenesis of rheumatoid arthritis (RA). Melanoma differentiation-associated gene 5 (MDA5) is an RNA helicase that plays a role in innate immune and inflammatory reactions. The details of the regulatory mechanisms of CXCL10 production and the precise role of MDA5 in RA synovitis have not been fully elucidated. The aim of this study was to examine the role of MDA5 in regulating CXCL10 expression in cultured human rheumatoid fibroblast-like synoviocytes (RFLS). RFLS was stimulated with Toll-like receptor 3 (TLR3) ligand polyinosinic:polycytidylic acid (poly I:C), a synthetic double-stranded RNA mimetic. Expression of interferon beta (IFN-β), MDA5, and CXCL10 was measured by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blotting, and enzyme-linked immunosorbent assay. A neutralizing antibody of IFN-β and siRNA-mediated MDA5 knockdown were used to determine the role of these molecules in regulating CXCL10 expression downstream of TLR3 signaling in RFLS. Poly I:C induced IFN-β, MDA5, and CXCL10 expression in a concentration- and time-dependent manner. IFN-β neutralizing antibody suppressed the expression of MDA5 and CXCL10, and knockdown of MDA5 decreased a part of CXCL10 expression (p < 0.001). The TLR3/IFN-β/CXCL10 axis may play a crucial role in the inflammatory responses in RA synovium, and MDA5 may be partially involved in this axis.


2007 ◽  
Vol 55 (2) ◽  
pp. 158-166 ◽  
Author(s):  
D SINISCALCO ◽  
C FUCCIO ◽  
C GIORDANO ◽  
F FERRARACCIO ◽  
E PALAZZO ◽  
...  

Stem Cells ◽  
2012 ◽  
Vol 31 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Feng Tao ◽  
Qun Li ◽  
Su Liu ◽  
Haiying Wu ◽  
John Skinner ◽  
...  

2019 ◽  
Vol 10 (1) ◽  
pp. 175-179 ◽  
Author(s):  
Xianhai Fang ◽  
Huacheng Zhou ◽  
Shaopeng Huang ◽  
Jinfeng Liu

Abstract Background This study determined the role of miR-1906 in neuropathic pain and proliferation in neuronal cells using a chronic constriction injury (CCI)-induced neuropathic pain (NP) rat model. Methodology NP was induced by CCI. Animals were divided into a sham group, an NP group, and a miR-1906 mimic group, which received 500 nmol/kg of a miR-1906 mimic intrathecally for 10 consecutive days following surgery. The effect of miR-1906 agomir was determined by estimating the thermal and mechanical withdrawal latency; an enzyme-linked immunosorbent assay (ELISA) was used to determine the concentration of proinflammatory mediators. Western blotting and reverse-transcription polymerase chain reaction (RT-PCR) were used to determine protein expression in the spinal tissues of the CCI-induced neuropathic pain rat model. Results Administration of miR-1906 agomir increased the mechanical and thermal withdrawal latency period and the levels of inflammatory mediators compared with the NP group. Western blotting showed that treatment with miR-1906 agomir attenuated the levels of Akt, mTOR, TLR-4, and PI3K proteins in the spinal tissues of the CCI-induced neuropathic pain model. TLR-4 and NF-κB gene expression was lower in the miR-1906 agomir group than in the NP group. Conclusion miR-1906 gene stimulation reduced neuropathic pain by enhancing Akt/nTOR/PI3K and TLR-4/NF-κB pathway regulation.


Author(s):  
Patrick L. Stemkowski ◽  
Peter A. Smith

Neuropathic pain often fails to respond to conventional pain management procedures. here we review the aetiology of neuropathic pain as would result from peripheral neuropathy or injury. We show that inflammatory mediators released from damaged nerves and tissue are responsible for triggering ectopic activity in primary afferents and that this, in turn, provokes increased spinal cord activity and the development of ‘central sensitization’. Although evidence is mounting to support the role of interleukin-1β, prostaglandins and other cytokines in the onset of neuropathic pain, the clinical efficacy of drugs which antagonize or prevent the actions of these mediators is yet to be determined. basic science findings do, however, support the use of pre-emptive analgesia during procedures which involve nerve manipulation and the use of anti-inflammatory steroids as soon as possible following traumatic nerve injury.


2010 ◽  
Vol 1198 (1) ◽  
pp. 168-172 ◽  
Author(s):  
Tera Hasbargen ◽  
Mostafa M. Ahmed ◽  
Gurwattan Miranpuri ◽  
Lin Li ◽  
Kristopher T. Kahle ◽  
...  

2019 ◽  
Vol 20 (14) ◽  
pp. 3574 ◽  
Author(s):  
Hye-Sun Lim ◽  
Yu Jin Kim ◽  
Bu-Yeo Kim ◽  
Soo-Jin Jeong

The purpose of the present study was to evaluate the effects of bakuchiol on the inflammatory response and to identify the molecular mechanism of the inflammatory effects in a lipopolysaccharide (LPS)-stimulated BV-2 mouse microglial cell line and mice model. The production of prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) was measured by enzyme-linked immunosorbent assay. The mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), TNF-α, and IL-6 was measured using reverse transcription–polymerase chain reaction analysis. Mitogen-activated protein kinase (MAPK) phosphorylation was determined by western blot analysis. In vitro experiments, bakuchiol significantly suppressed the production of PGE2 and IL-6 in LPS-stimulated BV-2 cells, without causing cytotoxicity. In parallel, bakuchiol significantly inhibited the LPS-stimulated expression of iNOS, COX-2, and IL-6 in BV-2 cells. However, bakuchiol had no effect on the LPS-stimulated production and mRNA expression of TNF-α or on LPS-stimulated c-Jun NH2-terminal kinase phosphorylation. In contrast, p38 MAPK and extracellular signal-regulated kinase (ERK) phosphorylation were inhibited by bakuchiol. In vivo experiments, Bakuchiol reduced microglial activation in the hippocampus and cortex tissue of LPS-injected mice. Bakuchiol significantly suppressed LPS-injected production of TNF-α and IL-6 in serum. These results indicate that the anti-neuroinflammatory effects of bakuchiol in activated microglia are mainly regulated by the inhibition of the p38 MAPK and ERK pathways. We suggest that bakuchiol may be beneficial for various neuroinflammatory diseases.


2020 ◽  
Vol 21 (15) ◽  
pp. 5330 ◽  
Author(s):  
Ramona D’Amico ◽  
Daniela Impellizzeri ◽  
Salvatore Cuzzocrea ◽  
Rosanna Di Paola

Neuropathic pain results from lesions or diseases of the somatosensory nervous system and it remains largely difficult to treat. Peripheral neuropathic pain originates from injury to the peripheral nervous system (PNS) and manifests as a series of symptoms and complications, including allodynia and hyperalgesia. The aim of this review is to discuss a novel approach on neuropathic pain management, which is based on the knowledge of processes that underlie the development of peripheral neuropathic pain; in particular highlights the role of glia and mast cells in pain and neuroinflammation. ALIAmides (autacoid local injury antagonist amides) represent a group of endogenous bioactive lipids, including palmitoylethanolamide (PEA), which play a central role in numerous biological processes, including pain, inflammation, and lipid metabolism. These compounds are emerging thanks to their anti-inflammatory and anti-hyperalgesic effects, due to the down-regulation of activation of mast cells. Collectively, preclinical and clinical studies support the idea that ALIAmides merit further consideration as therapeutic approach for controlling inflammatory responses, pain, and related peripheral neuropathic pain.


2006 ◽  
Vol 104 (2) ◽  
pp. 328-337 ◽  
Author(s):  
Darren D. O’Rielly ◽  
Christopher W. Loomis

Background Spinal prostaglandins seem to be important in the early pathogenesis of experimental neuropathic pain. Here, the authors investigated changes in the expression of cyclooxygenase and nitric oxide synthase (NOS) isoforms in the lumbar, thoracic, and cervical spinal cord and the pharmacologic sensitivity to spinal prostaglandin E2 (PGE2) after L5-L6 spinal nerve ligation (SNL). Methods Male Sprague-Dawley rats, fitted with intrathecal catheters, underwent SNL or sham surgery 3 days before experimentation. Paw withdrawal threshold was monitored for up to 20 days. Immunoblotting, spinal glutamate release, and behavioral testing were examined 3 days after SNL. Results Allodynia (paw withdrawal threshold &lt; or = 4 g) was evident 1 day after SNL and remained stable for 20 days. Paw withdrawal threshold was unchanged (P &gt; 0.05) from baseline (&gt; 15 g) after sham surgery except for a small but significant decrease on day 20. Cyclooxygenase 2, neuronal NOS, and inducible NOS were significantly increased in the ipsilateral lumbar dorsal horn after SNL. Expression in the contralateral dorsal horn and ventral horns (lumbar segments) or bilaterally (thoracic and cervical segments) was unchanged from sham controls. This was accompanied by a significant decrease in both the EC50 of PGE2-evoked glutamate release and the ED50 of PGE2 on brush-evoked allodynia. Enhanced sensitivity to PGE2 was localized to lumbar segments of SNL animals and attenuated by SC-51322 or S(+)-ibuprofen, but not R(-)-ibuprofen (100 mum). Conclusion The increased expression of cyclooxygense-2, neuronal NOS, and inducible NOS and the enhanced sensitivity to PGE2 in spinal segments affected by SNL support the hypothesis that spinal prostanoids play an early pathogenic role in experimental neuropathic pain.


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