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Cui L, Cai H, Sun F, Wang Y, Qu Y, Dong J, Wang H, Li J, Qian C, Li J. Beta-endorphin inhibits the inflammatory response of bovine endometrial cells through δ opioid receptor in vitro. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 121:104074. [PMID: 33775662 DOI: 10.1016/j.dci.2021.104074] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 03/16/2021] [Accepted: 03/16/2021] [Indexed: 06/12/2023]
Abstract
Postpartum uterine infections are common reproductive diseases in postpartum cows. Evidence has shown that plasma β-endorphins increase during bovine uterine inflammation. However, the effect of β-endorphins on the inflammatory response in bovine endometrium has not been clarified. The aim of this study was to investigate the effect of β-endorphins on the inflammatory response of bovine endometrial epithelial and stromal cells, and to explore the possible mechanism. The cells were treated with E. coli lipopolysaccharide (LPS) to simulate inflammation, which was characterized by the significant activation of NF-κB signaling pathway and the increased gene expression of the downstream proinflammatory cytokines (approximately 1.2- to 15-fold increase, P < 0.05). By using Western blot and qPCR techniques, we found that β-endorphins inhibited the key protein expression of NF-κB pathway, and the gene expressions of TNF, IL1B, IL6, CXCL8, nitric oxide synthase 2, and prostaglandin-endoperoxide synthase 2 (P < 0.05). The co-treatment of β-endorphins and opioid antagonists showed that the anti-inflammatory effect of β-endorphins could be blocked (P < 0.05) by non-selective opioid antagonist naloxone or δ opioid receptor antagonist ICI 154129, but not the μ opioid receptor antagonist CTAP (P > 0.05). In conclusion, β-endorphins may inhibit the inflammatory response of bovine endometrial epithelial and stromal cells through δ opioid receptor.
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Affiliation(s)
- Luying Cui
- College of Veterinary Medicine, Yangzhou University, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agriproduct Safety of the Ministry of Education, Yangzhou, Jiangsu, 225009, China
| | - Hele Cai
- College of Veterinary Medicine, Yangzhou University, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agriproduct Safety of the Ministry of Education, Yangzhou, Jiangsu, 225009, China
| | - Fazhuang Sun
- College of Veterinary Medicine, Yangzhou University, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agriproduct Safety of the Ministry of Education, Yangzhou, Jiangsu, 225009, China
| | - Yali Wang
- College of Veterinary Medicine, Yangzhou University, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agriproduct Safety of the Ministry of Education, Yangzhou, Jiangsu, 225009, China
| | - Yang Qu
- College of Veterinary Medicine, Yangzhou University, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agriproduct Safety of the Ministry of Education, Yangzhou, Jiangsu, 225009, China
| | - Junsheng Dong
- College of Veterinary Medicine, Yangzhou University, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agriproduct Safety of the Ministry of Education, Yangzhou, Jiangsu, 225009, China
| | - Heng Wang
- College of Veterinary Medicine, Yangzhou University, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agriproduct Safety of the Ministry of Education, Yangzhou, Jiangsu, 225009, China
| | - Jun Li
- College of Veterinary Medicine, Yangzhou University, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agriproduct Safety of the Ministry of Education, Yangzhou, Jiangsu, 225009, China
| | - Chen Qian
- College of Veterinary Medicine, Yangzhou University, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agriproduct Safety of the Ministry of Education, Yangzhou, Jiangsu, 225009, China
| | - Jianji Li
- College of Veterinary Medicine, Yangzhou University, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agriproduct Safety of the Ministry of Education, Yangzhou, Jiangsu, 225009, China.
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Mao XF, Wu HY, Tang XQ, Ali U, Liu H, Wang YX. Activation of GPR40 produces mechanical antiallodynia via the spinal glial interleukin-10/β-endorphin pathway. J Neuroinflammation 2019; 16:84. [PMID: 30981281 PMCID: PMC6461825 DOI: 10.1186/s12974-019-1457-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 03/22/2019] [Indexed: 12/27/2022] Open
Abstract
Background The G protein-coupled receptor 40 (GPR40), broadly expressed in various tissues such as the spinal cord, exerts multiple physiological functions including pain regulation. This study aimed to elucidate the mechanisms underlying GPR40 activation-induced antinociception in neuropathic pain, particularly related to the spinal glial expression of IL-10 and subsequent β-endorphin. Methods Spinal nerve ligation-induced neuropathic pain model was used in this study. β-Endorphin and IL-10 levels were measured in the spinal cord and cultured primary microglia, astrocytes, and neurons. Double immunofluorescence staining of β-endorphin with glial and neuronal cellular biomarkers was also detected in the spinal cord and cultured primary microglia, astrocytes, and neurons. Results GPR40 was expressed on microglia, astrocytes, and neurons in the spinal cords and upregulated by spinal nerve ligation. Intrathecal injection of the GPR40 agonist GW9508 dose-dependently attenuated mechanical allodynia and thermal hyperalgesia in neuropathic rats, with Emax values of 80% and 100% MPE and ED50 values of 6.7 and 5.4 μg, respectively. Its mechanical antiallodynia was blocked by the selective GPR40 antagonist GW1100 but not GPR120 antagonist AH7614. Intrathecal GW9508 significantly enhanced IL-10 and β-endorphin immunostaining in spinal microglia and astrocytes but not in neurons. GW9508 also markedly stimulated gene and protein expression of IL-10 and β-endorphin in cultured primary spinal microglia and astrocytes but not in neurons, originated from 1-day-old neonatal rats. The IL-10 antibody inhibited GW9508-stimulated gene expression of the β-endorphin precursor proopiomelanocortin (POMC) but not IL-10, whereas the β-endorphin antibody did not affect GW9508-stimulated IL-10 or POMC gene expression. GW9508 increased phosphorylation of mitogen-activated protein kinases (MAPKs) including p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK), and its stimulatory effects on IL-10 and POMC expression were blocked by each MAPK isoform inhibitor. Spinal GW9508-induced mechanical antiallodynia was completely blocked by intrathecal minocycline, IL-10 neutralizing antibody, β-endorphin antiserum, and μ-opioid receptor-preferred antagonist naloxone. Conclusions Our results illustrate that GPR40 activation produces antinociception via the spinal glial IL-10/β-endorphin antinociceptive pathway. Electronic supplementary material The online version of this article (10.1186/s12974-019-1457-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiao-Fang Mao
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai, 200240, China
| | - Hai-Yun Wu
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai, 200240, China
| | - Xue-Qi Tang
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai, 200240, China
| | - Usman Ali
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai, 200240, China
| | - Hao Liu
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai, 200240, China
| | - Yong-Xiang Wang
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai, 200240, China.
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Huang Q, Mao XF, Wu HY, Liu H, Sun ML, Wang X, Wang YX. Cynandione A attenuates neuropathic pain through p38β MAPK-mediated spinal microglial expression of β-endorphin. Brain Behav Immun 2017; 62:64-77. [PMID: 28189715 DOI: 10.1016/j.bbi.2017.02.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 01/23/2017] [Accepted: 02/07/2017] [Indexed: 12/27/2022] Open
Abstract
Cynanchi Wilfordii Radix (baishouwu), a medicinal herb, has been widely used in Asia to treat a variety of diseases or illnesses. Cynandione A isolated from C. Wilfordii is the principle acetophenone and exhibits neuroprotective and anti-inflammatory activities. This study aims to evaluate the antihypersensitivity activities of cynandione A in neuropathy and explored its mechanisms of action. Intrathecal injection of cynandione A dose-dependently attenuated spinal nerve ligation-induced mechanical allodynia and thermal hyperalgesia, with maximal possible effects of 57% and 59%, ED50s of 14.9μg and 6.5μg, respectively. Intrathecal injection of cynandione A significantly increased β-endorphin levels in spinal cords of neuropathic rats and its treatment concentration-dependently induced β-endorphin expression in cultured primary microglia (but not in neurons or astrocytes), with EC50s of 38.8 and 20.0μM, respectively. Cynandione A also non-selectively upregulated phosphorylation of mitogen-activated protein kinases (MAPKs), including p38, extracellular signal regulated kinase (ERK1/2), and extracellular signal regulated kinase (JNK) in primary microglial culture; however, cynandione A-stimulated β-endorphin expression was completely inhibited by the specific p38 activation inhibitor SB203580, but not by the ERK1/2 or JNK activation inhibitors. Knockdown of spinal p38β but not p38α using siRNA also completely blocked cynandione A-induced β-endorphin expression in cultured microglial cells. Furthermore, cynandione A-induced antiallodynia in neuropathy was totally inhibited by the microglial inhibitor minocycline, SB203580, anti-β-endorphin antibody, and μ-opioid receptor antagonist CTAP (but not the κ- or δ-opioid receptor antagonist). These results suggest that cynandione A attenuates neuropathic pain through upregulation of spinal microglial expression β-endorphin via p38β MAPK activation.
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Affiliation(s)
- Qian Huang
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai 200240, China.
| | - Xiao-Fang Mao
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai 200240, China.
| | - Hai-Yun Wu
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai 200240, China.
| | - Hao Liu
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai 200240, China.
| | - Ming-Li Sun
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai 200240, China.
| | - Xiao Wang
- Shandong Analysis and Test Center, Shandong Academy of Sciences, 19 Keyuan Street, Jinan 250014, Shandong, China.
| | - Yong-Xiang Wang
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai 200240, China.
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Neuropeptides and Microglial Activation in Inflammation, Pain, and Neurodegenerative Diseases. Mediators Inflamm 2017; 2017:5048616. [PMID: 28154473 PMCID: PMC5244030 DOI: 10.1155/2017/5048616] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/26/2016] [Accepted: 12/05/2016] [Indexed: 12/15/2022] Open
Abstract
Microglial cells are responsible for immune surveillance within the CNS. They respond to noxious stimuli by releasing inflammatory mediators and mounting an effective inflammatory response. This is followed by release of anti-inflammatory mediators and resolution of the inflammatory response. Alterations to this delicate process may lead to tissue damage, neuroinflammation, and neurodegeneration. Chronic pain, such as inflammatory or neuropathic pain, is accompanied by neuroimmune activation, and the role of glial cells in the initiation and maintenance of chronic pain has been the subject of increasing research over the last two decades. Neuropeptides are small amino acidic molecules with the ability to regulate neuronal activity and thereby affect various functions such as thermoregulation, reproductive behavior, food and water intake, and circadian rhythms. Neuropeptides can also affect inflammatory responses and pain sensitivity by modulating the activity of glial cells. The last decade has witnessed growing interest in the study of microglial activation and its modulation by neuropeptides in the hope of developing new therapeutics for treating neurodegenerative diseases and chronic pain. This review summarizes the current literature on the way in which several neuropeptides modulate microglial activity and response to tissue damage and how this modulation may affect pain sensitivity.
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Fan H, Li TF, Gong N, Wang YX. Shanzhiside methylester, the principle effective iridoid glycoside from the analgesic herb Lamiophlomis rotata, reduces neuropathic pain by stimulating spinal microglial β-endorphin expression. Neuropharmacology 2015; 101:98-109. [PMID: 26363192 DOI: 10.1016/j.neuropharm.2015.09.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 09/04/2015] [Accepted: 09/07/2015] [Indexed: 12/22/2022]
Abstract
Lamiophlomis rotata (L. rotata, Duyiwei) is an orally available Tibetan analgesic herb widely prescribed in China. Shanzhiside methylester (SM) is a principle effective iridoid glycoside of L. rotata and serves as a small molecule glucagon-like peptide-1 (GLP-1) receptor agonist. This study aims to evaluate the signal mechanisms underlying SM anti-allodynia, determine the ability of SM to induce anti-allodynic tolerance, and illustrate the interactions between SM and morphine, or SM and β-endorphin, in anti-allodynia and anti-allodynic tolerance. Intrathecal SM exerted dose-dependent and long-lasting (>4 h) anti-allodynic effects in spinal nerve injury-induced neuropathic rats, with a maximal inhibition of 49% and a projected ED50 of 40.4 μg. SM and the peptidic GLP-1 receptor agonist exenatide treatments over 7 days did not induce self-tolerance to anti-allodynia or cross-tolerance to morphine or β-endorphin. In contrast, morphine and β-endorphin induced self-tolerance and cross-tolerance to SM and exenatide. In the spinal dorsal horn and primary microglia, SM significantly evoked β-endorphin expression, which was completely prevented by the microglial inhibitor minocycline and p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580. SM anti-allodynia was totally inhibited by the GLP-1 receptor antagonist exendin(9-39), minocycline, β-endorphin antiserum, μ-opioid receptor antagonist CTAP, and SB203580. SM and exenatide specifically activated spinal p38 MAPK phosphorylation. These results indicate that SM reduces neuropathic pain by activating spinal GLP-1 receptors and subsequently stimulating microglial β-endorphin expression via the p38 MAPK signaling. Stimulation of the endogenous β-endorphin expression may be a novel and effective strategy for the discovery and development of analgesics for the long-term treatment of chronic pain.
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Affiliation(s)
- Hui Fan
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai, 200240, China
| | - Teng-Fei Li
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai, 200240, China
| | - Nian Gong
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai, 200240, China
| | - Yong-Xiang Wang
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, 800 Dongchuan Road, Shanghai, 200240, China.
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Fan H, Gong N, Li TF, Ma AN, Wu XY, Wang MW, Wang YX. The non-peptide GLP-1 receptor agonist WB4-24 blocks inflammatory nociception by stimulating β-endorphin release from spinal microglia. Br J Pharmacol 2014; 172:64-79. [PMID: 25176008 DOI: 10.1111/bph.12895] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 08/19/2014] [Accepted: 08/22/2014] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND AND PURPOSE Two peptide agonists of the glucagon-like peptide-1 (GLP-1) receptor, exenatide and GLP-1 itself, exert anti-hypersensitive effects in neuropathic, cancer and diabetic pain. In this study, we have assessed the anti-allodynic and anti-hyperalgesic effects of the non-peptide agonist WB4-24 in inflammatory nociception and the possible involvement of microglial β-endorphin and pro-inflammatory cytokines. EXPERIMENTAL APPROACH We used rat models of inflammatory nociception induced by formalin, carrageenan or complete Freund's adjuvant (CFA), to test mechanical allodynia and thermal hyperalgesia. Expression of β-endorphin and pro-inflammatory cytokines was measured using real-time quantitative PCR and fluorescent immunoassays. KEY RESULTS WB4-24 displaced the specific binding of exendin (9-39) in microglia. Single intrathecal injection of WB4-24 (0.3, 1, 3, 10, 30 and 100 μg) exerted dose-dependent, specific, anti-hypersensitive effects in acute and chronic inflammatory nociception induced by formalin, carrageenan and CFA, with a maximal inhibition of 60-80%. Spinal WB4-24 was not effective in altering nociceptive pain. Subcutaneous injection of WB4-24 was also antinociceptive in CFA-treated rats. WB4-24 evoked β-endorphin release but did not inhibit expression of pro-inflammatory cytokines in either the spinal cord of CFA-treated rats or cultured microglia stimulated by LPS. WB4-24 anti-allodynia was prevented by a microglial inhibitor, β-endorphin antiserum and a μ-opioid receptor antagonist. CONCLUSIONS AND IMPLICATIONS Our results suggest that WB4-24 inhibits inflammatory nociception by releasing analgesic β-endorphin rather than inhibiting the expression of proalgesic pro-inflammatory cytokines in spinal microglia, and that the spinal GLP-1 receptor is a potential target molecule for the treatment of pain hypersensitivity including inflammatory nociception.
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Affiliation(s)
- Hui Fan
- King's Lab, School of Pharmacy, Shanghai Jiao Tong University, Shanghai, China
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Activation of spinal glucagon-like peptide-1 receptors specifically suppresses pain hypersensitivity. J Neurosci 2014; 34:5322-34. [PMID: 24719110 DOI: 10.1523/jneurosci.4703-13.2014] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
This study aims to identify the inhibitory role of the spinal glucagon like peptide-1 receptor (GLP-1R) signaling in pain hypersensitivity and its mechanism of action in rats and mice. First, GLP-1Rs were identified to be specifically expressed on microglial cells in the spinal dorsal horn, and profoundly upregulated after peripheral nerve injury. In addition, intrathecal GLP-1R agonists GLP-1(7-36) and exenatide potently alleviated formalin-, peripheral nerve injury-, bone cancer-, and diabetes-induced hypersensitivity states by 60-90%, without affecting acute nociceptive responses. The antihypersensitive effects of exenatide and GLP-1 were completely prevented by GLP-1R antagonism and GLP-1R gene knockdown. Furthermore, exenatide evoked β-endorphin release from both the spinal cord and cultured microglia. Exenatide antiallodynia was completely prevented by the microglial inhibitor minocycline, β-endorphin antiserum, and opioid receptor antagonist naloxone. Our results illustrate a novel spinal dorsal horn microglial GLP-1R/β-endorphin inhibitory pathway in a variety of pain hypersensitivity states.
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Curto-Reyes V, Boto T, Hidalgo A, Menéndez L, Baamonde A. Antinociceptive effects induced through the stimulation of spinal cannabinoid type 2 receptors in chronically inflamed mice. Eur J Pharmacol 2011; 668:184-9. [PMID: 21771590 DOI: 10.1016/j.ejphar.2011.06.057] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 06/16/2011] [Accepted: 06/27/2011] [Indexed: 01/19/2023]
Abstract
The stimulation of spinal cannabinoid type 2 (CB(2)) receptors is a suitable strategy for the alleviation of experimental pain symptoms. Several reports have described the up-regulation of spinal cannabinoid CB(2) receptors in neuropathic settings together with the analgesic effects derived from their activation. Besides, we have recently reported in two murine bone cancer models that the intrathecal administration of cannabinoid CB(2) receptor agonists completely abolishes hyperalgesia and allodynia, whereas spinal cannabinoid CB(2) receptor expression remains unaltered. The present experiments were designed to measure the expression of spinal cannabinoid CB(2) receptors as well as the analgesic efficacy derived from their stimulation in mice chronically inflamed by the intraplantar injection of complete Freund's adjuvant 1 week before. Both spinal cannabinoid CB(2) receptors mRNA measured by real-time PCR and cannabinoid CB(2) receptor protein levels measured by western blot remained unaltered in inflamed mice. Besides, the intrathecal (i.t.) administration of the cannabinoid CB(2) receptor agonists AM1241, (R,S)-3-(2-Iodo-5-nitrobenzoyl)-1-(1-methyl-2-piperidinylmethyl)-1H-indole, (0.03-1 μg) and JWH 133, (6aR,10aR)-3-(1,1-Dimethylbutyl)-6a,7,10,10a-tetrahydro-6,6,9-trimethyl-6H-dibenzo[b,d]pyran, (3-30 μg) dose-dependently blocked inflammatory thermal hyperalgesia and mechanical allodynia. The analgesic effects induced by both agonists were counteracted by the coadministration of the selective cannabinoid CB(2) receptor antagonist SR144528, 5-(4-chloro-3-methylphenyl)-1-[(4-methylphenyl)methyl]-N-[(1S,2S,4R)-1,3,3-trimethylbicyclo[2.2.1]hept-2-yl]-1H-pyrazole-3-carboxamide, (5 μg) but not by the cannabinoid CB(1) receptor antagonist AM251, N-(Piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide, (10 μg). The effects induced by AM1241 were also inhibited by the coadministration of the opioid receptor antagonist, naloxone (1 μg). These results demonstrate that effective analgesia can be achieved in chronic inflammatory settings through the stimulation of spinal cannabinoid CB(2) receptors even if this receptor population is not up-regulated.
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Affiliation(s)
- Verdad Curto-Reyes
- Laboratorio de Farmacología, Facultad de Medicina, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, Facultad de Medicina C/ Julián Clavería, 6. 33006 Oviedo, Asturias, Spain.
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Lin HC, Yang CM, Liu CL, Hu ML. Synergistic effects of homocysteine, S-adenosylhomocysteine and adenosine on apoptosis in BV-2 murine microglial cells. Biofactors 2008; 34:81-95. [PMID: 19706975 DOI: 10.1002/biof.5520340201] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Homocysteine (Hcy), S-adenosylhomocysteine (SAH) and adenosine (Ado) are methionine metabolism intermediates that may act synergistically in certain disease. In this study, we examined whether HCy, SAH and Ado may synergistically induce neuronal apoptosis of BV-2 microglial cells. We found that an incubation of BV-2 cells with 1 mM Hcy, 1 muM SAH and 100 muM Ado (SAH + Hcy + Ado) led to marked apoptosis of BV-2 cells, as evidenced by several markers of apoptosis. A synergistic effect of SAH + Hcy + Ado on apoptosis (2.55-fold, P < 0.05) was obtained, as calculated using the data of Annexin V-positive cells. This combination markedly induced intracellular levels of reactive oxygen species (ROS) starting at 6 h and significantly decreased the mitochondrial potential starting at 12 h. The combination significantly elevated caspase-9 and caspase-3 activities at 24 and 48 h. The combination also induced hypomethylation (at 24 and 48 h), as indicated by significantly decreased 5-methyldeoxycytidine levels and SAM/SAH ratios. Pre-incubation of cells with alpha-tocopherol (30 muM) reduced the increase of ROS (at 6 h) and significantly restored cell viability (at 24 and 48~h) in the SAH + Hcy + Ado group. Overall, the present study demonstrates that SAH, Hcy and Ado synergistically induce BV-2 apoptosis, possibly by generation of ROS and induction of intracellular hypomethylation.
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Affiliation(s)
- Hung-Chi Lin
- Department of Food Science and Biotechnology, National Chung Hsing University, Taiwan
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Ock J, Lee H, Kim S, Lee WH, Choi DK, Park EJ, Kim SH, Kim IK, Suk K. Induction of microglial apoptosis by corticotropin-releasing hormone. J Neurochem 2006; 98:962-72. [PMID: 16893426 DOI: 10.1111/j.1471-4159.2006.03933.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Neuropeptides are short-chain peptides found in brain tissue, some of which function as neurotransmitters and others as hormones. Neuropeptides may directly or indirectly modulate glial functions in the CNS. In the present study, effects of various neuropeptides on the viability and inflammatory activation of cultured microglia were investigated. Vasoactive intestinal peptide, substance P, cholecystokinin and neuropeptide Y did not affect microglial cell viability, whereas corticotropin-releasing hormone (CRH) induced a classical apoptosis of mouse microglia in culture as shown by nuclear condensation and fragmentation, terminal deoxynucleotidyl transferase dUTP nick-end labeling, and cleavage of caspase 3 and poly(ADP-ribose) polymerase protein. CRH, however, did not influence nitric oxide production or expression of inflammatory genes including those encoding cytokines and chemokines, indicating that CRH did not affect the inflammatory activation of microglia. The CRH-induced microglial apoptosis appeared to involve a mitochondrial pathway and reactive oxygen species, based on the mitochondrial membrane potential change, caspase 9 activation and sensitivity to antioxidants. Taken together, our results indicate that the stress neuropeptide CRH may regulate neuroinflammation by inducing the apoptosis of microglia, the major cellular source of inflammatory mediators in the CNS.
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Affiliation(s)
- Jiyeon Ock
- Department of Pharmacology, Kyungpook National University School of Medicine, Daegu, Korea
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Town T, Jeng D, Alexopoulou L, Tan J, Flavell RA. Microglia recognize double-stranded RNA via TLR3. THE JOURNAL OF IMMUNOLOGY 2006; 176:3804-12. [PMID: 16517751 DOI: 10.4049/jimmunol.176.6.3804] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Microglia are CNS resident innate immune cells of myeloid origin that become activated and produce innate proinflammatory molecules upon encountering bacteria or viruses. TLRs are a phylogenetically conserved diverse family of sensors for pathogen-associated molecular patterns that drive innate immune responses. We have recently shown that mice deficient in TLR3 (TLR3(-/-) mice) are resistant to lethal encephalitis and have reduced microglial activation after infection with West Nile virus, a retrovirus that produces dsRNA. We wished to determine whether microglia recognize dsRNA through the TLR3 pathway. In vitro, murine wild-type primary cultured microglia responded to synthetic dsRNA polyinosinic-polycytidylic acid (poly(I:C)) by increasing TLR3 and IFN-beta mRNA and by morphologic activation. Furthermore, wild-type microglia dose dependently secreted TNF-alpha and IL-6 after poly(I:C) challenge, whereas TLR3(-/-) microglia produced diminished cytokines. Activation of MAPK occurred in a time-dependent fashion following poly(I:C) treatment of wild-type microglia, but happened with delayed kinetics in TLR3(-/-) microglia. As an in vivo model of encephalitis, wild-type or TLR3(-/-) mice were injected intracerebroventricularly with poly(I:C) or LPS, and microglial activation was assessed by cell surface marker or phospho-MAPK immunofluorescence. After intracerebroventricular injection of poly(I:C), microgliosis was clearly evident in wild-type mice but was nearly absent in TLR3(-/-) animals. When taken together, our results demonstrate that microglia recognize dsRNA through TLR3 and associated signaling molecules and suggest that these cells are key sensors of dsRNA-producing viruses that may invade the CNS.
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Affiliation(s)
- Terrence Town
- Section of Immunobiology, Yale University School of Medicine, 300 Cedar Street, New Haven, CT 06520, USA
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Abstract
Schizophrenia is a devastating illness of unknown etiology. It is characterized by increased brain ventricular volume, suggesting a progressive neurodevelopmental condition. There is evidence suggesting a correlation between in utero viral exposure and subsequent occurrence of schizophrenia. Many neurotransmitter systems have been implicated as being dysfunctional in schizophrenia. There are also data suggesting immune system dysfunction in schizophrenia, and a negative correlation between schizophrenia and rheumatoid arthritis. Microglia are phagocytic immune cells in the central nervous system (CNS) derived from peripheral blood monocytes. They are involved in brain development, neuroproliferative and neurodegenerative activities, several CNS illnesses, and CNS viral immunity. They may also be involved in neurotransmitter regulation. The current theory postulates microglial dysfunction initiated by early CNS viral exposure results in the abnormal neural development and neurotransmitter dysfunction seen in schizophrenia.
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Affiliation(s)
- N A Munn
- Behavioral Health Clinic of St. Peter's Hospital, Helena, MT 59601, USA
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Dobrenis K. Microglia in cell culture and in transplantation therapy for central nervous system disease. Methods 1998; 16:320-44. [PMID: 10071070 DOI: 10.1006/meth.1998.0688] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The central nervous system (CNS) is host to a significant population of macrophage-like cells known as microglia. In addition to these cells which reside within the parenchyma, a diverse array of macrophages are present in meningeal, perivascular, and other peripheral locations. The role that microglia and other CNS macrophages play in disease and injury is under intensive investigation, and functions in development and in the normal adult are just beginning to be explored. At present the biology of these cells represents one of the most fertile areas of CNS research. This article describes methodology for the isolation and maintenance of microglia in cell cultures prepared from murine and feline animals. Various approaches to identify microglia are provided, using antibody, lectin, or scavenger receptor ligand. Assays to confirm macrophage-like functional activity, including phagocytosis, lysosomal enzyme activity, and motility, are described. Findings regarding the origin and development of microglia and results of transplantation studies are reviewed. Based on these data, a strategy is presented that proposes to use the microglial cell lineage to effectively deliver therapeutic compounds to the CNS from the peripheral circulation.
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Affiliation(s)
- K Dobrenis
- Department of Neuroscience, Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Feindt J, Schmidt A, Mentlein R. Receptors and effects of the inhibitory neuropeptide somatostatin in microglial cells. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1998; 60:228-33. [PMID: 9757047 DOI: 10.1016/s0169-328x(98)00184-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The expression of receptors for the neuropeptide somatostatin was investigated in cultured immunocytochemically pure rat microglial cells. By the reverse transcriptase-polymerase chain reaction, the mRNAs for the receptor subtypes sst2, sst3 and sst4, but not sst1 and sst5 could be detected. To show that these receptors were functionally active, the effects of somatostatin and the metabolically stable, receptor subtype (2, 3 and 5) selective derivative octreotide (SMS 201-995, Sandostatin) on protein phosphorylation and proliferation were evaluated. Somatostatin induced the tyrosine phosphorylation of a 95 kDa protein in microglia. Furthermore, somatostatin or octreotide inhibited the basal as well as the GM-CSF-(granulocyte macrophage colony-stimulating factor) or the IL-3-(interleukin-3)-stimulated proliferation of microglial cells. This effect was dose-dependent, with a half maximum activity of about 0.2-0.3 nM. Somatostatin was relatively stable in the cultures due to protease inhibitors in the serum. The results indicate that microglial cells are targets for the widespread neuropeptide somatostatin and that its receptors can transduce complex signals to microglia.
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Affiliation(s)
- J Feindt
- Anatomisches Institut der Universität Kiel, Olshausenstrasse 40, D-24098, Kiel, Germany
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Passani L, Elkabes S, Coyle JT. Evidence for the presence of N-acetylaspartylglutamate in cultured oligodendrocytes and LPS activated microglia. Brain Res 1998; 794:143-5. [PMID: 9630582 DOI: 10.1016/s0006-8993(98)00308-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The levels of N-acetylaspartylglutamate (NAAG) were determined by HPLC in untreated or lipopolysaccharide (LPS) activated pure astrocyte, oligodendrocyte, and microglial cultures derived from developing rat brain. Oligodendrocyte cultures expressed 1.52+/-0.12 nmol/microg protein of NAAG, whereas astrocyte cultures (0.04+/-0.08 nmol/microg protein) and untreated microglial cultures (0.05+/-0.09 nmol/microg protein) contained only trace amounts of the dipeptide. After stimulation of microglial cultures for 24 h with LPS, NAAG levels increased significantly to 0.37+/-0.12 SD nmol/microg protein. NAAG levels in astrocyte and oligodendrocyte cultures remained unchanged after LPS treatment. The findings indicate that NAAG is localized to specific glial cell types. Further our results suggest that NAAG biosynthesis is induced in microglia, activated by specific stimuli.
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Affiliation(s)
- L Passani
- Laboratory of Molecular and Developmental Neuroscience, Massachusetts General Hospital, Charlestown, MA 02129, USA.
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Taupenot L, Ciesielski-Treska J, Ulrich G, Chasserot-Golaz S, Aunis D, Bader MF. Chromogranin A triggers a phenotypic transformation and the generation of nitric oxide in brain microglial cells. Neuroscience 1996; 72:377-89. [PMID: 8737408 DOI: 10.1016/0306-4522(96)83172-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Chromogranin A is an ubiquitous 48,000 mol. wt secretory protein stored and released from many neuroendocrine cells and neurons. In human brain, chromogranin A is a common feature of regions that are known to be affected by various neurodegenerative pathologies such as Alzheimer's, Parkinson's and Pick's diseases. Brain degenerative areas are generally infiltrated by activated microglial cells, the resident macrophage cell population within the central nervous system. Here, we report that both recombinant human chromogranin A and chromogranin A purified from bovine chromaffin granules trigger drastic morphological changes in rat microglial cells maintained in culture. Microglial cells exposed to chromogranin A adopted a flattened amoeboid shape and, this change was associated with an accumulation of actin in the subplasmalemmal region, as observed by immunocytochemistry and confocal laser microscopy. In single microglial cells loaded with indo-1, chromogranin A elicited a rapid and transient increase in [Ca2+]i which preceded the reorganization of actin cytoskeleton. The activity of nitric oxide synthase was estimated by measuring the accumulation of nitrite in the culture medium. Both recombinant human chromogranin A and bovine chromogranin A triggered an important accumulation of nitrite comparable to that induced by lipopolysaccharide, a well-known activator of microglia. The effect of chromogranin A was dose dependent, inhibited by N omega-nitro-L-arginine methyl ester, a competitive inhibitor of nitric oxide synthase, and by cycloheximide, an inhibitor of protein synthesis. These findings suggest that chromogranin A induces an activated phenotype of microglia, and thus may have a role in the pathogenesis of neuronal degeneration in the brain.
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Affiliation(s)
- L Taupenot
- Unité INSERM U-338 Biologie de la Communication Cellulaire, Strasbourg, France
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Abstract
Cysteine lysosomal proteases are essential for turnover of intracellular and extracellular proteins. These enzymes are strongly implicated in normal and pathological processes involving tissue remodeling. Among the cysteine proteases, cathepsin S seems to be best suited for such a process since it retains most of its enzymatic activity at neutral pH. In situ hybridization analyses of the adult rat brain, spleen, and lung reveal that cathepsin S mRNA is preferentially expressed in cells of mononuclear-phagocytic origin. After entorhinal cortex lesion of adult rat brain (a paradigm for neuronal degeneration and reactive synaptogenesis), cathepsin S mRNA is dramatically increased in activated microglia in the deafferented dentate gyrus and in macrophages at the wound site, suggesting a role in lesion-induced tissue remodeling. This possibility is further supported by the finding that cathepsin S degrades a number of extracellular matrix molecules at neutral pH and by the finding that inflammatory mediators stimulate its secretion from the microglia and macrophages. These data suggest that cathepsin S is an important player in degenerative disorders associated with the cells of the mononuclear phagocytic system.
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Affiliation(s)
- S Petanceska
- Department of Pharmacology, New York University Medical Center, New York, New York 10016, USA
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Provis JM, Penfold PL, Edwards AJ, van Driel D. Human retinal microglia: expression of immune markers and relationship to the glia limitans. Glia 1995; 14:243-56. [PMID: 8530182 DOI: 10.1002/glia.440140402] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The immunoreactivity, morphology and relationship to the glia limitans of microglia were investigated in flatmounts and sections of normal human retina, using immunogold histochemistry, electron microscopy (EM), and antibodies directed against CD45, major histocompatability complex class I (MHC-I), MHC-II, and human macrophage antigens. Immunoreactivity was evident for all antibodies tested, including MHC-I, which labeled both microglia and retinal vascular endothelium. Most consistent labeling was obtained using antibodies to CD45, MHC-II, and anti-human macrophage (S22) antigen. Immunoreactive cells were seen in the perivascular space (perivascular cells), where they were closely adherent to the vessel profile, and in the retinal parenchyma (microglia). Some parenchymal microglia were also vessel associated and by EM were seen to be closely related to the glia limitans (paravascular microglia). Paravascular microglia were shown by optical densitometry, to express higher levels of MHC antigens than neighboring, non-vessel associated, parenchymal microglia. In addition, paravascular microglia were macrophage (S22) antigen positive, while other parenchymal microglia did not express macrophage antigens. Quantitative data indicate that similar populations of microglia are immunoreactive to CD45, MHC-I, and MHC-II, while relatively few microglia (approximately 10%) are immunoreactive for human macrophage (S22) antigens, supporting previous suggestions that microglia are a heterogeneous population.
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Affiliation(s)
- J M Provis
- Save Sight and Eye Health Institute, Department of Clinical Ophthalmology, University of Sydney, Australia
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Lutz MB, Granucci F, Winzler C, Marconi G, Paglia P, Foti M, Assmann CU, Cairns L, Rescigno M, Ricciardi-Castagnoli P. Retroviral immortalization of phagocytic and dendritic cell clones as a tool to investigate functional heterogeneity. J Immunol Methods 1994; 174:269-79. [PMID: 8083532 DOI: 10.1016/0022-1759(94)90031-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We have developed a method to generate immortalized phagocytic and dendritic cell clones from various mouse tissues such as spleen, thymus, brain and bone marrow. The clones were phenotypically characterized and shown to retain the ability to respond to immune or inflammatory signals, e.g., IFN-gamma. Functional cytokine activity and nitric oxide production were maintained in activated macrophages, microglial and dendritic cell clones. Immune functions, such as antigen presentation was exhibited by all clones whereas tissue-specific properties such as the ability to respond to corticotropin-releasing hormone and produce beta-endorphin was shown in microglial cell clones but not in macrophage cell clones, indicating that heterogeneity of cells of the mononuclear-phagocytic lineage can be maintained in vitro after the immortalization procedure. Moreover, the continuous proliferation of the clones could be inhibited by various stimuli and further differentiation of the cells could be achieved in vitro.
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Affiliation(s)
- M B Lutz
- CNR Center of Cytopharmacology, University of Milan, Italy
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