1
|
Qin QR, Xu ZQ, Liu TT, Li XM, Qiu CY, Hu WP. CCK-8 enhances acid-sensing ion channel currents in rat primary sensory neurons. Neuropharmacology 2023; 241:109739. [PMID: 37820935 DOI: 10.1016/j.neuropharm.2023.109739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/07/2023] [Accepted: 09/28/2023] [Indexed: 10/13/2023]
Abstract
Cholecystokinin (CCK) is a peptide that has been implicated in pain modulation. Acid sensitive ion channels (ASICs) also play an important role in pain associated with tissue acidification. However, it is still unclear whether there is an interaction between CCK signaling and ASICs during pain process. Herein, we report that a functional link between them in rat dorsal root ganglion (DRG) neurons. Pretreatment with CCK-8 concentration-dependently increased acid-evoked ASIC currents. CCK-8 increased the maximum response of ASICs to acid, but did not changed their acid sensitivity. Enhancement of ASIC currents by CCK-8 was mediated by the stimulation of CCK2 receptor (CCK2R), rather than CCK1R. The enhancement of ASIC currents by CCK-8 was prevented by application of either G-protein inhibitor GDP-β-S or protein kinase C (PKC) inhibitor GF109203×, but not by protein kinase A (PKA) inhibitor H-89 or JNK inhibitor SP600125. Moreover, CCK-8 increased the number of action potentials triggered by acid stimuli by activating CCK2R. Finally, CCK-8 dose-dependently exacerbated acid-induced nociceptive behavior in rats through local CCK2R. Together, these results indicated that CCK-8/CCK2R activation enhanced ASIC-mediated electrophysiological activity in DRG neurons and nociception in rats. The enhancement effect depended on G-proteins and intracellular PKC signaling rather than PKA and JNK signaling pathway. These findings provided that CCK-8/CCK2R is an important therapeutic target for ASIC-mediated pain.
Collapse
Affiliation(s)
- Qing-Rui Qin
- School of Pharmacy, School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Zhong-Qing Xu
- School of Pharmacy, School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Ting-Ting Liu
- School of Pharmacy, School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Xue-Mei Li
- School of Pharmacy, School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Chun-Yu Qiu
- School of Pharmacy, School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China.
| | - Wang-Ping Hu
- School of Pharmacy, School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China; Department of Physiology, Hubei College of Chinese Medicine, 87 Xueyuan Road, Jingzhou 434020, Hubei, PR China.
| |
Collapse
|
2
|
Osmakov DI, Tarasova NV, Nedorubov AA, Palikov VA, Palikova YA, Dyachenko IA, Andreev YA, Kozlov SA. Nocistatin and Products of Its Proteolysis Are Dual Modulators of Type 3 Acid-Sensing Ion Channels (ASIC3) with Algesic and Analgesic Properties. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:2137-2145. [PMID: 38462456 DOI: 10.1134/s0006297923120155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/27/2023] [Accepted: 10/30/2023] [Indexed: 03/12/2024]
Abstract
The neuropeptide nocistatin (NS) is expressed by the nervous system cells and neutrophils as a part of a precursor protein and can undergo stepwise limited proteolysis. Previously, it was shown that rat NS (rNS) is able to activate acid-sensing ion channels (ASICs) and that this effect correlates with the acidic nature of NS. Here, we investigated changes in the properties of rNS in the course of its proteolytic degradation by comparing the effects of the full-size rNS and its two cleavage fragments on the rat isoform 3 ASICs (ASIC3) expressed in X. laevis oocytes and pain perception in mice. The rNS acted as both positive and negative modulator by lowering the steady-state desensitization of ASIC3 at pH 6.8-7.0 and reducing the channel's response to stimuli at pH 6.0-6.9, respectively. The truncated rNSΔ21 peptide lacking 21 amino acid residues from the N-terminus retained the positive modulatory activity, while the C-terminal pentapeptide (rNSΔ30) acted only as a negative ASIC3 modulator. The effects of the studied peptides were confirmed in animal tests: rNS and rNSΔ21 induced a pain-related behavior, whereas rNSΔ30 showed the analgesic effect. Therefore, we have shown that the mode of rNS action changes during its stepwise degradation, from an algesic molecule through a pain enhancer to a pain reliever (rNSΔ30 pentapeptide), which can be considered as a promising drug candidate.
Collapse
Affiliation(s)
- Dmitry I Osmakov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, 119991, Russia
| | - Nadezhda V Tarasova
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, 119991, Russia.
| | - Andrey A Nedorubov
- Institute of Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow, 119991, Russia.
| | - Victor A Palikov
- Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino, 142290, Russia.
| | - Yulia A Palikova
- Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino, 142290, Russia.
| | - Igor A Dyachenko
- Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Pushchino, 142290, Russia.
| | - Yaroslav A Andreev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, 119991, Russia
| | - Sergey A Kozlov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
| |
Collapse
|
3
|
Zhao L, Liu S, Zhang X, Yang J, Mao M, Zhang S, Xu S, Feng S, Wang X. Satellite glial cell-secreted exosomes after in-vitro oxaliplatin treatment presents a pro-nociceptive effect for dorsal root ganglion neurons and induce mechanical hypersensitivity in naïve mice. Mol Cell Neurosci 2023; 126:103881. [PMID: 37467904 DOI: 10.1016/j.mcn.2023.103881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 06/29/2023] [Accepted: 07/15/2023] [Indexed: 07/21/2023] Open
Abstract
BACKGROUND The pathophysiological mechanism underlying chemotherapy-induced neuropathic pain (CINP) remains unclear. Sensory neuronal hypersensitivity in the dorsal root ganglion (DRG) is essential for the onset and maintenance of chronic pain. Satellite glial cells (SGCs) in the DRG potentially affect the function of sensory neurons, possibly by mediating extracellular or paracrine signaling. Exosomes play an essential role in cell-cell communication. However, the role of SGC-secreted exosomes in glia-neuron communication and CINP remains unclear. METHODS SGCs and sensory neurons were cultured from the DRG of mice. The SGCs were treated with 4 μM oxaliplatin for 24 h. Glial fibrillary acid protein (GFAP) and connexin-43 (Cx-43) expressions in the SGCs were examined with immunocytochemistry (ICC). Enzyme-linked immunosorbent assay (ELISA) detected cytokine release in the SGCs after oxaliplatin treatment. Subsequently, SGC-secreted exosomes were collected using ultracentrifugation and identified by nanoparticle tracking analysis, transmission electron microscopy, and western blotting. Subsequently, DRG neurons were incubated with SGC-secreted exosomes for 24 h. The percentage of reactive oxygen species (ROS)-positive neurons was detected using flow cytometry, and acid-sensing ion channel 3 (ASIC3) and transient receptor potential vanilloid 1 (TRPV1) expression were examined by western blotting. SGC-secreted exosomes were intrathecally injected into naïve mice. The mechanical withdrawal threshold was assessed 24, 48, and 72 h following the injection. TRPV1 expression in the DRG was examined 72 h after intrathecal injection. Furthermore, differentially expressed (DE) miRNAs within the SGC-secreted exosomes were detected using RNA sequencing and bioinformatics analysis. Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG), and Reactome pathway analyses were performed to predict the function of the target genes of DE miRNAs. Finally, the DE miRNAs with pain regulation potential were identified in silico. RESULTS After in-vitro oxaliplatin treatment, ICC showed an increase in the immunoreactivity of GFAP and Cx-43 in the SGCs. ELISA results suggested an increased release of tumor necrosis factor-α and interleukin (IL)-1β, but a decreased release of IL-10. Oxaliplatin treatment increased the secretion of exosomes in the SGCs from 4.34 to 5.99 × 1011 (particles/ml). The exosome-specific markers CD9 and TSG101 were positive, whereas calnexin was negative for the obtained exosomes. Additionally, the SGC-secreted exosomes were endocytosed by DRG neurons after co-incubation. Moreover, after incubation with conditioned SGC-secreted exosomes (after 4 μM oxaliplatin treatment), the percentage of ROS-positive DRG neurons increased and ASIC3 and TRPV1 expressions were upregulated. After the intrathecal injection of the conditioned SGC-secreted exosomes, the mice presented with mechanical hypersensitivity and TRPV1 expression upregulation in the DRG. Notably, 25 and 120 significantly upregulated and downregulated miRNAs, respectively, were identified in the conditioned SGC-secreted exosomes. When predicting the function of target genes of DE miRNAs, certain GO terms, such as synapse organization, neurogenesis regulation, histone modification, and pain-related KEGG or Reactome pathways, including vascular endothelial growth factor A-vascular endothelial growth factor receptor 2, mammalian target of rapamycin, and mitogen-activated protein kinase signaling pathways, related to nervous system function were predicted. Finally, 27 pain regulation-related miRNAs, including miR-324-3p, miR-181a-5p, and miR-122-5p, were identified in silico. CONCLUSION Our study demonstrates that SGC-secreted exosomes after in-vitro oxaliplatin treatment present a pro-nociceptive effect for DRG neurons and induce mechanical hypersensitivity in naïve mice, possibly via the contained miRNA cargo. Identifying the candidate miRNAs and verifying their functions in vivo are required to elucidate the exosomes mediating 'glia-neuron' communication under CINP condition.
Collapse
Affiliation(s)
- Liping Zhao
- Department of Anesthesiology, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, Jiangsu Province, China
| | - Shijiang Liu
- Department of Anesthesiology and Perioperative Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Xiaobao Zhang
- Department of Anesthesiology, The First People's Hospital of Lianyungang City, Lianyungang, Jiangsu Province, China
| | - Juan Yang
- Department of Anesthesiology, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, Jiangsu Province, China
| | - Mao Mao
- Department of Anesthesiology, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, Jiangsu Province, China
| | - Susu Zhang
- Department of Anesthesiology, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, Jiangsu Province, China
| | - Shiqin Xu
- Department of Anesthesiology, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, Jiangsu Province, China.
| | - Shanwu Feng
- Department of Anesthesiology, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, Jiangsu Province, China.
| | - Xian Wang
- Department of Anesthesiology, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, Jiangsu Province, China.
| |
Collapse
|
4
|
Stover JD, Trone MA, Lawrence B, Bowles RD. Multiplex epigenome editing of ion channel expression in nociceptive neurons abolished degenerative IVD-conditioned media-induced mechanical sensitivity. JOR Spine 2023; 6:e1253. [PMID: 37361323 PMCID: PMC10285767 DOI: 10.1002/jsp2.1253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 01/15/2023] [Accepted: 02/27/2023] [Indexed: 06/28/2023] Open
Abstract
Background Low back pain is a major contributor to disability worldwide and generates a tremendous socioeconomic impact. The degenerative intervertebral disc (IVD) has been hypothesized to contribute to discogenic pain by sensitizing nociceptive neurons innervating the disc to stimuli that is nonpainful in healthy patients. Previously, we demonstrated the ability of degenerative IVDs to sensitize neurons to mechanical stimuli; however, elucidation of degenerative IVDs discogenic pain mechanisms is required to develop therapeutic strategies that directly target these mechanisms. Aims In this study, we utilized CRISPR epigenome editing of nociceptive neurons to identify mechanisms of degenerative IVD-induced changes to mechanical nociception and demonstrated the ability of multiplex CRISPR epigenome editing of nociceptive neurons to modulate inflammation-induced mechanical nociception. Methods and Results Utilizing an in vitro model, we demonstrated degenerative IVD-produced IL-6-induced increases in nociceptive neuron activity in response to mechanical stimuli, mediated by TRPA1, ASIC3, and Piezo2 ion channel activity. Once these ion channels were identified as mediators of degenerative IVD-induced mechanical nociception, we developed singleplex and multiplex CRISPR epigenome editing vectors that modulate endogenous expression of TRPA1, ASIC3, and Piezo2 via targeted gene promoter histone methylation. When delivered to nociceptive neurons, the multiplex CRISPR epigenome editing vectors abolished degenerative IVD-induced mechanical nociception while preserving nonpathologic neuron activity. Conclusion This work demonstrates the potential of multiplex CRISPR epigenome editing as a highly targeted gene-based neuromodulation strategy for the treatment of discogenic pain, specifically; and, for the treatment of inflammatory chronic pain conditions, more broadly.
Collapse
Affiliation(s)
- Joshua D. Stover
- Department of BioengineeringUniversity of UtahSalt Lake CityUtahUSA
| | - Matthew A. Trone
- Department of BioengineeringUniversity of UtahSalt Lake CityUtahUSA
| | - Brandon Lawrence
- Department of OrthopaedicsUniversity of UtahSalt Lake CityUtahUSA
| | - Robby D. Bowles
- Department of BioengineeringUniversity of UtahSalt Lake CityUtahUSA
- Department of OrthopaedicsUniversity of UtahSalt Lake CityUtahUSA
| |
Collapse
|
5
|
Group II metabotropic glutamate receptor activation attenuates acid-sensing ion channel currents in rat primary sensory neurons. J Biol Chem 2023; 299:102953. [PMID: 36731795 PMCID: PMC9976456 DOI: 10.1016/j.jbc.2023.102953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 02/01/2023] Open
Abstract
Acid-sensing ion channels (ASICs) play an important role in pain associated with tissue acidification. Peripheral inhibitory group II metabotropic glutamate receptors (mGluRs) have analgesic effects in a variety of pain conditions. Whether there is a link between ASICs and mGluRs in pain processes is still unclear. Herein, we show that the group II mGluR agonist LY354740 inhibited acid-evoked ASIC currents and action potentials in rat dorsal root ganglia neurons. LY354740 reduced the maximum current response to protons, but it did not change the sensitivity of ASICs to protons. LY354740 inhibited ASIC currents by activating group II mGluRs. We found that the inhibitory effect of LY354740 was blocked by intracellular application of the Gi/o protein inhibitor pertussis toxin and the cAMP analogue 8-Br-cAMP and mimicked by the protein kinase A (PKA) inhibitor H-89. LY354740 also inhibited ASIC3 currents in CHO cells coexpressing mGluR2 and ASIC3 but not in cells expressing ASIC3 alone. In addition, intraplantar injection of LY354740 dose-dependently alleviated acid-induced nociceptive behavior in rats through local group II mGluRs. Together, these results suggested that activation of peripheral group II mGluRs inhibited the functional activity of ASICs through a mechanism that depended on Gi/o proteins and the intracellular cAMP/PKA signaling pathway in rat dorsal root ganglia neurons. We propose that peripheral group II mGluRs are an important therapeutic target for ASIC-mediated pain.
Collapse
|
6
|
Li Q, Qiao W, Hao J, Wei S, Li X, Liu T, Qiu C, Hu W. Potentiation of ASIC currents by lysophosphatidic acid in rat dorsal root ganglion neurons. J Neurochem 2022; 163:327-337. [DOI: 10.1111/jnc.15690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 08/08/2022] [Accepted: 08/11/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Qing Li
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology Xianning Hubei China
- School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology Xianning Hubei China
| | - Wen‐Long Qiao
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology Xianning Hubei China
- School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology Xianning Hubei China
| | - Jia‐Wei Hao
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology Xianning Hubei China
- School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology Xianning Hubei China
| | - Shuang Wei
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology Xianning Hubei China
- School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology Xianning Hubei China
| | - Xue‐Mei Li
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology Xianning Hubei China
| | - Ting‐Ting Liu
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology Xianning Hubei China
| | - Chun‐Yu Qiu
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology Xianning Hubei China
| | - Wang‐Ping Hu
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology Xianning Hubei China
- Hubei College of Chinese Medicine Jingzhou Hubei China
| |
Collapse
|
7
|
Wei S, Liu TT, Hu WP, Qiu CY. Resveratrol inhibits the activity of acid-sensing ion channels in male rat dorsal root ganglion neurons. J Neurosci Res 2022; 100:1755-1764. [PMID: 35592934 DOI: 10.1002/jnr.25060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 04/16/2022] [Accepted: 04/22/2022] [Indexed: 11/07/2022]
Abstract
Resveratrol can relieve pain under various pain conditions. One of the mechanisms of resveratrol analgesia is the regulation of ion channels. Acid-sensing ion channels (ASICs) are expressed predominantly in nociceptive sensory neurons to detect changes in extracellular pH. ASICs are important players in pain associated with tissue acidification. However, it is still unclear whether ASICs are resveratrol targets. Electrophysiological recordings showed that resveratrol decreased acid-induced and ASIC-mediated currents in male rat dorsal root ganglion (DRG) neurons in a concentration-dependent manner. Resveratrol downwardly shifted the concentration-response curve for protons, suggesting that it inhibited ASICs not by changing the pH0.5 , but by suppressing the proton-induced maximum response. It also suppressed acid-triggered action potentials in the rat DRG neurons. Finally, intraplantar pretreatment with resveratrol relieved acid-induced nociceptive responses in male rats in a dose-dependent manner. These results indicated that resveratrol inhibited ASIC-mediated electrophysiological activity and nociception, suggesting a novel peripheral mechanism underlying its analgesic effect.
Collapse
Affiliation(s)
- Shuang Wei
- School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology, Xianning, PR China.,School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, Xianning, PR China
| | - Ting-Ting Liu
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, Xianning, PR China
| | - Wang-Ping Hu
- School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, Xianning, PR China.,Department of Physiology, Hubei College of Chinese Medicine, Jingzhou, PR China
| | - Chun-Yu Qiu
- School of Pharmacy, Xianning Medical College, Hubei University of Science and Technology, Xianning, PR China.,School of Basic Medical Sciences, Xianning Medical College, Hubei University of Science and Technology, Xianning, PR China
| |
Collapse
|
8
|
Periodontal acidification contributes to tooth pain hypersensitivity during orthodontic tooth movement. Neurosci Res 2021; 177:103-110. [PMID: 34808249 DOI: 10.1016/j.neures.2021.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/18/2021] [Accepted: 11/18/2021] [Indexed: 12/24/2022]
Abstract
Tooth movements associated with orthodontic treatment often cause tooth pain. However, the detailed mechanism remains unclear. Here, we examined the involvement of periodontal acidification caused by tooth movement in mechanical tooth pain hypersensitivity. Elastics were inserted between the first and second molars to move the teeth in Sprague-Dawley rats. Mechanical head-withdrawal reflex threshold to first molar stimulation and the pH of the gingival sulcus around the tooth were measured. The expression of acid-sensing ion channel 3 (ASIC3) in trigeminal ganglion neurons and phosphorylation of ASIC3 in the periodontal tissue were analyzed. The mechanical head-withdrawal reflex threshold to first molar stimulation and pH in the gingival sulcus decreased on day 1 after the elastic insertion. These decreases recovered to the sham level by buffering periodontal acidification. Periodontal inhibition of ASIC3 channel activity reversed the decreased mechanical head-withdrawal reflex threshold to first molar stimulation. On day 1 after elastic insertion, the tooth movement did not change the number of ASIC3 immunoreactive trigeminal ganglion neurons innervating the periodontal tissue but increased phosphorylated-ASIC3 levels in the periodontal tissue. Periodontal acidification induced by tooth movement causes phosphorylation of ASIC3, resulting in mechanical pain hypersensitivity in mechanically forced tooth.
Collapse
|
9
|
The development of proteinase-activated receptor-2 modulators and the challenges involved. Biochem Soc Trans 2021; 48:2525-2537. [PMID: 33242065 PMCID: PMC7752072 DOI: 10.1042/bst20200191] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/13/2020] [Accepted: 11/02/2020] [Indexed: 11/30/2022]
Abstract
Protease-activated receptor-2 (PAR2) has been extensively studied since its discovery in the mid-1990. Despite the advances in understanding PAR2 pharmacology, it has taken almost 25 years for the first inhibitor to reach clinical trials, and so far, no PAR2 antagonist has been approved for human use. Research has employed classical approaches to develop a wide array of PAR2 agonists and antagonists, consisting of peptides, peptoids and antibodies to name a few, with a surge in patent applications over this period. Recent breakthroughs in PAR2 structure determination has provided a unique insight into proposed PAR2 ligand binding sites. Publication of the first crystal structures of PAR2 resolved in complex with two novel non-peptide small molecule antagonists (AZ8838 and AZ3451) revealed two distinct binding pockets, originally presumed to be allosteric sites, with a PAR2 antibody (Fab3949) used to block tethered ligand engagement with the peptide-binding domain of the receptor. Further studies have proposed orthosteric site occupancy for AZ8838 as a competitive antagonist. One company has taken the first PAR2 antibody (MEDI0618) into phase I clinical trial (NCT04198558). While this first-in-human trial is at the early stages of the assessment of safety, other research into the structural characterisation of PAR2 is still ongoing in an attempt to identify new ways to target receptor activity. This review will focus on the development of novel PAR2 modulators developed to date, with an emphasis placed upon the advances made in the pharmacological targeting of PAR2 activity as a strategy to limit chronic inflammatory disease.
Collapse
|
10
|
Morgan M, Thai J, Trinh P, Habib M, Effendi KN, Ivanusic JJ. ASIC3 inhibition modulates inflammation-induced changes in the activity and sensitivity of Aδ and C fiber sensory neurons that innervate bone. Mol Pain 2021; 16:1744806920975950. [PMID: 33280501 PMCID: PMC7724402 DOI: 10.1177/1744806920975950] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The Acid Sensing Ion Channel 3 (ASIC3) is a non-selective cation channel that is
activated by acidification, and is known to have a role in regulating
inflammatory pain. It has pro-algesic roles in a range of conditions that
present with bone pain, but the mechanism for this has not yet been
demonstrated. We aimed to determine if ASIC3 is expressed in Aδ and/or C fiber
bone afferent neurons, and to explore its role in the activation and
sensitization of bone afferent neurons after acute inflammation. A combination
of retrograde tracing and immunohistochemistry was used to determine expression
of ASIC3 in the soma of bone afferent neurons. A novel, in
vivo, electrophysiological bone-nerve preparation was used to make
recordings of the activity and sensitivity of bone afferent neurons in the
presence of carrageenan-induced inflammation, with and without the selective
ASIC3 inhibitor APET×2. A substantial proportion of bone afferent neurons
express ASIC3, including unmyelinated (neurofilament poor) and small diameter
myelinated (neurofilament rich) neurons that are likely to be C and Aδ nerve
fibers respectively. Electrophysiological recordings revealed that application
of APET×2 to the marrow cavity inhibited carrageenan-induced spontaneous
activity of C and Aδ fiber bone afferent neurons. APET×2 also inhibited
carrageenan-induced sensitization of Aδ and C fiber bone afferent neurons to
mechanical stimulation, but had no effect on the sensitivity of bone afferent
neurons in the absence of inflammation. This evidence supports a role for ASIC3
in the pathogenesis of pain associated with inflammation of the bone.
Collapse
Affiliation(s)
- Michael Morgan
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Jenny Thai
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Phu Trinh
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Mohamed Habib
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Kelly N Effendi
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Jason J Ivanusic
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| |
Collapse
|
11
|
Wei S, Qiu CY, Jin Y, Liu TT, Hu WP. Dexmedetomidine Inhibits ASIC Activity via Activation of α 2A Adrenergic Receptors in Rat Dorsal Root Ganglion Neurons. Front Pharmacol 2021; 12:685460. [PMID: 34108881 PMCID: PMC8181722 DOI: 10.3389/fphar.2021.685460] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/11/2021] [Indexed: 01/13/2023] Open
Abstract
Dexmedetomidine (DEX), a selective α2 adrenergic receptor (α2-AR) agonist, has been shown to have peripheral analgesic effects in a variety of pain conditions. However, the precise molecular mechanisms have not yet been fully elucidated. Acid sensing ion channels (ASICs) are the major player in pain associated with tissue acidosis. Given that both α2-ARs and ASICs exist in dorsal root ganglia (DRG) neurons, we therefore investigated the effects of DEX on the functional activity of ASICs. Herein, whole-cell patch-clamp recordings demonstrated that DEX suppressed ASIC-mediated and acid-evoked currents and action potentials in dissociated rat DRG neurons. DEX shifted downwards concentration-response curve to protons, with a decrease of 35.83 ± 3.91% in the maximal current response to pH 4.5. DEX-induced inhibition of ASIC currents was blocked by the α2A-AR antagonist BRL44408 in DRG neurons. DEX also inhibited ASIC3 currents in CHO cells co-expressing ASIC3 and α2A-ARs, but not in ASIC3 transfected CHO cells without α2A-ARs expression. DEX-induced inhibition of ASIC currents was mimicked by the protein kinase A inhibitor H-89, and blocked by intracellular application of the Gi/o protein inhibitor pertussis toxin and the cAMP analog 8-Br-cAMP. In addition, peripherally administration of DEX dose-dependently relieved nociceptive responses to intraplantar injection of acetic acid in rats through local α2A-ARs. Our results indicated that DEX inhibited the functional activity of ASICs via α2A-ARs and intracellular Gi/o proteins and cAMP/protein kinase A signaling pathway in rat DRG neurons, which was a novel potential mechanism that probably mediated peripheral analgesia of DEX.
Collapse
Affiliation(s)
- Shuang Wei
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China.,Department of Pharmacology, Hubei University of Science and Technology, Xianning, China
| | - Chun-Yu Qiu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China
| | - Ying Jin
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China
| | - Ting-Ting Liu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China
| | - Wang-Ping Hu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, China
| |
Collapse
|
12
|
Inhibition of ASIC-Mediated Currents by Activation of Somatostatin 2 Receptors in Rat Dorsal Root Ganglion Neurons. Mol Neurobiol 2021; 58:2107-2117. [PMID: 33411247 DOI: 10.1007/s12035-020-02257-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 12/09/2020] [Indexed: 12/18/2022]
Abstract
Somatostatin (SST) and its analogues like octreotide (OCT) have analgesic effect on a variety of pain through peripheral SST receptors (SSTRs). However, the precise molecular mechanisms have not yet been fully elucidated. This research aimed to identify possible antinociceptive mechanisms, showing functional links of the SSTR2 and acid-sensing ion channels (ASICs). Herein, we reported that OCT inhibited the electrophysiological activity of ASICs in rat dorsal root ganglia (DRG) neurons. OCT concentration-dependently decreased the peak amplitude of acid-evoked inward currents, which were mediated by ASICs. OCT shifted concentration-response curve to protons downwards, with a decrease of 36.53 ± 5.28% in the maximal current response to pH 4.5 in the presence of OCT. OCT inhibited ASIC-mediated currents through SSTR2, since the inhibition was blocked by Cyn 154806, a specific SSTR2 antagonist. The OCT inhibition of ASIC-mediated currents was mimicked by H-89, a membrane-permeable inhibitor of PKA, and reversed by internal treatment of an adenylyl cyclase activator forskolin or 8-Br-cAMP. OCT also decreased the number of action potentials induced by acid stimuli through SSTR2. Finally, peripheral administration of 20 μM OCT, but not 2 μM OCT, significantly relieved nociceptive responses to intraplantar injection of acetic acid in rats. This occurred through local activation of SSTR2 in the injected hindpaw and was reversed following co-application of Cyn 154806. Our results indicate that activation SSTR2 by OCT can inhibit the activity of ASICs via an intracellular cAMP and PKA signaling pathway in rat DRG neurons. These observations demonstrate a cross-talk between ASICs and SSTR2 in peripheral sensory neurons, which was a novel peripheral analgesic mechanism of SST and its analogues.
Collapse
|
13
|
Endothelin-1 enhances acid-sensing ion channel currents in rat primary sensory neurons. Acta Pharmacol Sin 2020; 41:1049-1057. [PMID: 32107467 PMCID: PMC7468575 DOI: 10.1038/s41401-019-0348-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 12/12/2019] [Indexed: 11/18/2022] Open
Abstract
Endothelin-1 (ET-1), an endogenous vasoactive peptide, has been found to play an important role in peripheral pain signaling. Acid-sensing ion channels (ASICs) are key sensors for extracellular protons and contribute to pain caused by tissue acidosis. It remains unclear whether an interaction exists between ET-1 and ASICs in primary sensory neurons. In this study, we reported that ET-1 enhanced the activity of ASICs in rat dorsal root ganglia (DRG) neurons. In whole-cell voltage-clamp recording, ASIC currents were evoked by brief local application of pH 6.0 external solution in the presence of TRPV1 channel blocker AMG9810. Pre-application with ET-1 (1−100 nM) dose-dependently increased the proton-evoked ASIC currents with an EC50 value of 7.42 ± 0.21 nM. Pre-application with ET-1 (30 nM) shifted the concentration–response curve of proton upwards with a maximal current response increase of 61.11% ± 4.33%. We showed that ET-1 enhanced ASIC currents through endothelin-A receptor (ETAR), but not endothelin-B receptor (ETBR) in both DRG neurons and CHO cells co-expressing ASIC3 and ETAR. ET-1 enhancement was inhibited by blockade of G-protein or protein kinase C signaling. In current-clamp recording, pre-application with ET-1 (30 nM) significantly increased acid-evoked firing in rat DRG neurons. Finally, we showed that pharmacological blockade of ASICs by amiloride or APETx2 significantly alleviated ET-1-induced flinching and mechanical hyperalgesia in rats. These results suggest that ET-1 sensitizes ASICs in primary sensory neurons via ETAR and PKC signaling pathway, which may contribute to peripheral ET-1-induced nociceptive behavior in rats.
Collapse
|
14
|
Wang X, Li T. Postoperative pain pathophysiology and treatment strategies after CRS + HIPEC for peritoneal cancer. World J Surg Oncol 2020; 18:62. [PMID: 32234062 PMCID: PMC7110707 DOI: 10.1186/s12957-020-01842-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/20/2020] [Indexed: 02/08/2023] Open
Abstract
Background Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is a treatment choice for peritoneal cancer. However, patients commonly suffer from severe postoperative pain. The pathophysiology of postoperative pain is considered to be from both nociceptive and neuropathic origins. Main body The recent advances on the etiology of postoperative pain after CRS + HIPEC treatment were described, and the treatment strategy and outcomes were summarized. Conclusion Conventional analgesics could provide short-term symptomatic relief. Thoracic epidural analgesia combined with opioids administration could be an effective treatment choice. In addition, a transversus abdominis plane block could also be an alternative option, although further studies should be performed.
Collapse
Affiliation(s)
- Xiao Wang
- Department of Anesthesiology, Beijing Shijitan Hospital, Capital Medical University, No. 10 Tieyi Road, Yangfangdian, Haidian District, Beijing, 100038, China
| | - Tianzuo Li
- Department of Anesthesiology, Beijing Shijitan Hospital, Capital Medical University, No. 10 Tieyi Road, Yangfangdian, Haidian District, Beijing, 100038, China.
| |
Collapse
|
15
|
Zhou YM, Wu L, Wei S, Jin Y, Liu TT, Qiu CY, Hu WP. Enhancement of acid-sensing ion channel activity by prostaglandin E2 in rat dorsal root ganglion neurons. Brain Res 2019; 1724:146442. [PMID: 31513790 DOI: 10.1016/j.brainres.2019.146442] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 07/12/2019] [Accepted: 09/07/2019] [Indexed: 11/16/2022]
Abstract
Prostaglandin E2 (PGE2) and proton are typical inflammatory mediators. They play a major role in pain processing and hypersensitivity through activating their cognate receptors expressed in terminals of nociceptive sensory neurons. However, it remains unclear whether there is an interaction between PGE2 receptors and proton-activated acid-sensing ion channels (ASICs). Herein, we show that PGE2 enhanced the functional activity of ASICs in rat dorsal root ganglion (DRG) neurons through EP1 and EP4 receptors. In the present study, PGE2 concentration-dependently increased ASIC currents in DRG neurons. It shifted the proton concentration-response curve upwards, without change in the apparent affinity of proton for ASICs. Moreover, PGE2 enhancement of ASIC currents was partially blocked by EP1 or EP4 receptor antagonist. PGE2 failed to enhance ASIC currents when simultaneous blockade of both EP1 and EP4 receptors. PGE2 enhancement was partially suppressed after inhibition of intracellular PKC or PKA signaling, and completely disappeared after concurrent blockade of both PKC and PKA signaling. PGE2 increased significantly the expression levels of p-PKCε and p-PKA in DRG cells. PGE2 also enhanced proton-evoked action potentials in rat DRG neurons. Finally, peripherally administration of PGE2 dose-dependently exacerbated acid-induced nocifensive behaviors in rats through EP1 and EP4 receptors. Our results indicate that PGE2 enhanced the electrophysiological activity of ASICs in DRG neurons and contributed to acidosis-evoked pain, which revealed a novel peripheral mechanism underlying PGE2 involvement in hyperalgesia by sensitizing ASICs in primary sensory neurons.
Collapse
Affiliation(s)
- Yi-Mei Zhou
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China; Department of Pharmacology, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Lei Wu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Shuang Wei
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China; Department of Pharmacology, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Ying Jin
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China; Department of Pharmacology, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Ting-Ting Liu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China; Department of Physiology, School of Basic Medical Sciences, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Chun-Yu Qiu
- Department of Pharmacology, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China
| | - Wang-Ping Hu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China; Department of Physiology, School of Basic Medical Sciences, Hubei University of Science and Technology, 88 Xianning Road, Xianning 437100, Hubei, PR China.
| |
Collapse
|
16
|
Ding N, Jiang J, Qin P, Wang Q, Hu J, Li Z. Mast cells are important regulator of acupoint sensitization via the secretion of tryptase, 5-hydroxytryptamine, and histamine. PLoS One 2018. [PMID: 29513755 PMCID: PMC5841809 DOI: 10.1371/journal.pone.0194022] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mast cells (MCs) play a crucial role in mediating the establishment of networks among the circulatory, nervous and immune system at acupoints. However, the changes which occur in MCs during acupoint sensitization, i.e. the dynamic transformation of an acupoint from a "silenced" to an "activated" status, remain uncharacterized. To investigate the morphological and functional changes of MCs as an aid to understanding the cellular mechanism underlying acupoint sensitization, a rat model of knee osteoarthritis (OA) was induced by an injection of mono-iodoacetate (MIA) on day 0. On day 14, toluidine blue and immunofluorescence staining were used to observe the recruitment and degranulation of MCs and the release of mast cell co-expressed mediators: tryptase, 5-hydroxytryptamine (5-HT) and histamine (HA) at the acupoints Yanglingquan (GB34), Heding (EX-LE2) and Weizhong (BL40). Results showed that the number of MCs as well as the percentages of degranulated and extensively degranulated MCs at the acupoints GB34 and EX-LE2 in the light (A), mild (B), heavy (C) osteoarthritis groups were larger than those in the normal control (N) and normal saline (NS) groups (p < 0.01). Comparisons among the A, B and C groups suggested that the number and the degranulation extent of the MCs at the acupoints GB34 and EX-LE2 were positively correlated with the severity of the disease. Some MCs in the A, B and C group showed the release of 5-HT, HA, and tryptase in degranulation at the acupoints GB34 and EX-LE2. Such changes in MCs were not observed at the acupoint BL40. In conclusion, this study confirmed that acupoint sensitization is associated with the increase in recruitment and degranulation levels of MCs on a acupoint-specific and disease severity-dependent manner. The release of tryptase, 5-HT, and HA during MC degranulation is likely to be one of the cellular mechanisms occurring during acupoint sensitization.
Collapse
Affiliation(s)
- Ning Ding
- School of Acupuncture, Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing, China
| | - Jing Jiang
- School of Nursing, Beijing University of Chinese Medicine, Beijing, China
| | - Pingping Qin
- School of Acupuncture, Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing, China
| | - Qiaoxia Wang
- School of Acupuncture, Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing, China
| | - Jiatong Hu
- School of Acupuncture, Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing, China
| | - Zhigang Li
- School of Acupuncture, Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing, China
| |
Collapse
|
17
|
Nazıroğlu M, Braidy N. Thermo-Sensitive TRP Channels: Novel Targets for Treating Chemotherapy-Induced Peripheral Pain. Front Physiol 2017; 8:1040. [PMID: 29326595 PMCID: PMC5733463 DOI: 10.3389/fphys.2017.01040] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 11/29/2017] [Indexed: 12/19/2022] Open
Abstract
Abnormal Ca2+ channel physiology, expression levels, and hypersensitivity to heat have been implicated in several pain states following treatment with chemotherapeutic agents. As members of the Ca2+ permeable transient receptor potential (TRP), five of the channels (TRPV1-4 and TRPM2) are activated by different heat temperatures, and two of the channels (TRPA1 and TRPM8) are activated by cold temperature. Accumulating evidences indicates that antagonists of TRPA1 and TRPM8 may protect against cisplatin, oxaliplatin, and paclitaxel-induced mitochondrial oxidative stress, inflammation, cold allodynia, and hyperalgesia. TRPV1 was responsible from the cisplatin-induced heat hyperalgesia and mechanical allodynia in the sensory neurons. TRPA1, TRPM8, and TRPV2 protein expression levels were mostly increased in the dorsal root (DRG) and trigeminal ganglia by these treatments. There is a debate on direct or oxaliplatin-induced oxidative cold stress dependent TRPA1 and TRPV4 activation in the DRG. Involvement of molecular pathways such as cysteine groups, glutathione metabolism, anandamide, cAMP, lipopolysaccharide, proteinase-activated receptor 2, and mitogen-activated protein kinase were also indicated in the oxaliplatin and paclitaxel-induced cold allodynia. In this review, we summarized results of five temperature-regulated TRP channels (TRPA1, TRPM8, TRPV1, TRPV2, and TRPV4) as novel targets for treating chemotherapy-induced peripheral pain
Collapse
Affiliation(s)
- Mustafa Nazıroğlu
- Neuroscience Research Center, Suleyman Demirel University, Isparta, Turkey
| | - Nady Braidy
- Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales, Sydney, NSW, Australia
| |
Collapse
|
18
|
Wu J, Wang JJ, Liu TT, Zhou YM, Qiu CY, Shen DW, Hu WP. PPAR-α acutely inhibits functional activity of ASICs in rat dorsal root ganglion neurons. Oncotarget 2017; 8:93051-93062. [PMID: 29190977 PMCID: PMC5696243 DOI: 10.18632/oncotarget.21805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 08/29/2017] [Indexed: 12/29/2022] Open
Abstract
Peroxisome proliferator-activated receptor-α (PPAR-α), a lipid activated transcription factor of nuclear hormone receptor superfamily, can relieve pain through a rapid-response mechanism. However, little is known about the underlying mechanism. Herein, we report that PPAR-α activation acutely inhibits the functional activity of acid-sensing ion channels (ASICs), key sensors for extracellular protons, in rat dorsal root ganglion (DRG) neurons. Pre-application of PPAR-α agonist GW7647 for 2 min decreased the amplitude of proton-gated currents mediated by ASICs in a concentration-dependent manner. GW7647 shifted the concentration-response curve for proton downwards, with a decrease of 36.9 ± 2.3% in the maximal current response to proton. GW7647 inhibition of proton-gated currents can be blocked by GW6471, a selective PPAR-α antagonist. Moreover, PPAR-α activation decreased the number of acidosis-evoked action potentials in rat DRG neurons. Finally, peripheral administration of GW7647 dose-dependently relieved nociceptive responses to injection of acetic acid in rats. These results indicated that activation of peripheral PPAR-α acutely inhibited functional activity of ASICs in a non-genomic manner, which revealed a novel mechanism underlying rapid analgesia through peripheral PPAR-α.
Collapse
Affiliation(s)
- Jing Wu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China
| | - Jia-Jia Wang
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China
| | - Ting-Ting Liu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China.,Department of Physiology, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China
| | - Yi-Mei Zhou
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China
| | - Chun-Yu Qiu
- Department of Pharmacology, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China
| | - Ding-Wen Shen
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China
| | - Wang-Ping Hu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China.,Department of Physiology, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China
| |
Collapse
|