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Balbi M, Bonanno G, Bonifacino T, Milanese M. The Physio-Pathological Role of Group I Metabotropic Glutamate Receptors Expressed by Microglia in Health and Disease with a Focus on Amyotrophic Lateral Sclerosis. Int J Mol Sci 2023; 24:ijms24065240. [PMID: 36982315 PMCID: PMC10048889 DOI: 10.3390/ijms24065240] [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: 01/20/2023] [Revised: 03/03/2023] [Accepted: 03/06/2023] [Indexed: 03/30/2023] Open
Abstract
Microglia cells are the resident immune cells of the central nervous system. They act as the first-line immune guardians of nervous tissue and central drivers of neuroinflammation. Any homeostatic alteration that can compromise neuron and tissue integrity could activate microglia. Once activated, microglia exhibit highly diverse phenotypes and functions related to either beneficial or harmful consequences. Microglia activation is associated with the release of protective or deleterious cytokines, chemokines, and growth factors that can in turn determine defensive or pathological outcomes. This scenario is complicated by the pathology-related specific phenotypes that microglia can assume, thus leading to the so-called disease-associated microglia phenotypes. Microglia express several receptors that regulate the balance between pro- and anti-inflammatory features, sometimes exerting opposite actions on microglial functions according to specific conditions. In this context, group I metabotropic glutamate receptors (mGluRs) are molecular structures that may contribute to the modulation of the reactive phenotype of microglia cells, and this is worthy of exploration. Here, we summarize the role of group I mGluRs in shaping microglia cells' phenotype in specific physio-pathological conditions, including some neurodegenerative disorders. A significant section of the review is specifically focused on amyotrophic lateral sclerosis (ALS) since it represents an entirely unexplored topic of research in the field.
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Affiliation(s)
- Matilde Balbi
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
| | - Giambattista Bonanno
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
- IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genoa, Italy
| | - Tiziana Bonifacino
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
- Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), 56122 Pisa, Italy
| | - Marco Milanese
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
- IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genoa, Italy
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Ji B, Wojtaś B, Skup M. Molecular Identification of Pro-Excitogenic Receptor and Channel Phenotypes of the Deafferented Lumbar Motoneurons in the Early Phase after SCT in Rats. Int J Mol Sci 2022; 23:ijms231911133. [PMID: 36232433 PMCID: PMC9569670 DOI: 10.3390/ijms231911133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/19/2022] [Accepted: 09/19/2022] [Indexed: 02/07/2023] Open
Abstract
Spasticity impacts the quality of life of patients suffering spinal cord injury and impedes the recovery of locomotion. At the cellular level, spasticity is considered to be primarily caused by the hyperexcitability of spinal α-motoneurons (MNs) within the spinal stretch reflex circuit. Here, we hypothesized that after a complete spinal cord transection in rats, fast adaptive molecular responses of lumbar MNs develop in return for the loss of inputs. We assumed that early loss of glutamatergic afferents changes the expression of glutamatergic AMPA and NMDA receptor subunits, which may be the forerunners of the developing spasticity of hindlimb muscles. To better understand its molecular underpinnings, concomitant expression of GABA and Glycinergic receptors and serotoninergic and noradrenergic receptors, which regulate the persistent inward currents crucial for sustained discharges in MNs, were examined together with voltage-gated ion channels and cation-chloride cotransporters. Using quantitative real-time PCR, we showed in the tracer-identified MNs innervating extensor and flexor muscles of the ankle joint multiple increases in transcripts coding for AMPAR and 5-HTR subunits, along with a profound decrease in GABAAR, GlyR subunits, and KCC2. Our study demonstrated that both MNs groups similarly adapt to a more excitable state, which may increase the occurrence of extensor and flexor muscle spasms.
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Affiliation(s)
- Benjun Ji
- Group of Restorative Neurobiology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Bartosz Wojtaś
- Laboratory of Sequencing, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Małgorzata Skup
- Group of Restorative Neurobiology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
- Correspondence:
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Metabotropic glutamate receptor 5 inhibits α-synuclein-induced microglia inflammation to protect from neurotoxicity in Parkinson's disease. J Neuroinflammation 2021; 18:23. [PMID: 33461598 PMCID: PMC7814625 DOI: 10.1186/s12974-021-02079-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 01/07/2021] [Indexed: 12/19/2022] Open
Abstract
Background Microglia activation induced by α-synuclein (α-syn) is one of the most important factors in Parkinson’s disease (PD) pathogenesis. However, the molecular mechanisms by which α-syn exerts neuroinflammation and neurotoxicity remain largely elusive. Targeting metabotropic glutamate receptor 5 (mGluR5) has been an attractive strategy to mediate microglia activation for neuroprotection, which might be an essential regulator to modulate α-syn-induced neuroinflammation for the treatment of PD. Here, we showed that mGluR5 inhibited α-syn-induced microglia inflammation to protect from neurotoxicity in vitro and in vivo. Methods Co-immunoprecipitation assays were utilized to detect the interaction between mGluR5 and α-syn in microglia. Griess, ELISA, real-time PCR, western blotting, and immunofluorescence assays were used to detect the regulation of α-syn-induced inflammatory signaling, cytokine secretion, and lysosome-dependent degradation. Results α-syn selectively interacted with mGluR5 but not mGluR3, and α-syn N terminal deletion region was essential for binding to mGluR5 in co-transfected HEK293T cells. The interaction between these two proteins was further detected in BV2 microglia, which was inhibited by the mGluR5 specific agonist CHPG without effect by its selective antagonist MTEP. Moreover, in both BV2 cells and primary microglia, activation of mGluR5 by CHPG partially inhibited α-syn-induced inflammatory signaling and cytokine secretion and also inhibited the microglia activation to protect from neurotoxicity. We further found that α-syn overexpression decreased mGluR5 expression via a lysosomal pathway, as evidenced by the lysosomal inhibitor, NH4Cl, by blocking mGluR5 degradation, which was not evident with the proteasome inhibitor, MG132. Additionally, co-localization of mGluR5 with α-syn was detected in lysosomes as merging with its marker, LAMP-1. Consistently, in vivo experiments with LPS- or AAV-α-syn-induced rat PD model also confirmed that α-syn accelerated lysosome-dependent degradation of mGluR5 involving a complex, to regulate neuroinflammation. Importantly, the binding is strengthened with LPS or α-syn overexpression but alleviated by urate, a potential clinical biomarker for PD. Conclusions These findings provided evidence for a novel mechanism by which the association of α-syn with mGluR5 was attributed to α-syn-induced microglia activation via modulation of mGluR5 degradation and its intracellular signaling. This may be a new molecular target for an effective therapeutic strategy for PD pathology. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-021-02079-1.
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Huang YY, Zhang Q, Zhang JN, Zhang YN, Gu L, Yang HM, Xia N, Wang XM, Zhang H. Triptolide up-regulates metabotropic glutamate receptor 5 to inhibit microglia activation in the lipopolysaccharide-induced model of Parkinson's disease. Brain Behav Immun 2018; 71:93-107. [PMID: 29649522 DOI: 10.1016/j.bbi.2018.04.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 03/27/2018] [Accepted: 04/07/2018] [Indexed: 12/11/2022] Open
Abstract
Metabotropic glutamate receptor (mGlu)5 regulates microglia activation, which contributes to inflammation. However, the role of mGlu5 in neuroinflammation associated with Parkinson's disease (PD) remains unclear. Triptolide (T10) exerts potent immunosuppressive and anti-inflammatory effects and protects neurons by inhibiting microglia activation. In this study, we investigated the role of mGlu5 in the anti-inflammatory effect of T10 in a lipopolysaccharide (LPS)-induced PD model. In cultured BV2 cells and primary microglia, blocking mGlu5 activity or knocking down its expression abolished T10-inhibited release of proinflammatory cytokines induced by LPS. Moreover, T10 up-regulated mGlu5 expression decreased by LPS through enhancing mRNA expression and protein stability. T10 also reversed the reduction in mGlu5 membrane localization and modulated receptor-mediated mitogen-activated protein kinase activity induced by LPS. Pharmacological inhibition of signaling molecules increased nitric oxide level and inducible nitric oxide synthase (iNOS), tumor necrosis factor-α, and interleukin (IL)-1β and -6 transcript levels that were downregulated by treatment with T10. Consistent with these in vitro findings, blocking mGlu5 attenuated the anti-inflammatory effects of T10 in an LPS-induced PD model and blocked the decreases in the number and morphology of ionized calcium binding adaptor molecule 1-positive microglia and LPS-induced iNOS protein expression caused by T10 treatment. Besides, mGlu5 mediated the effect of T10 on microglia-induced astrocyte activation in vitro and in vivo. The findings provide evidence for a novel mechanism by which mGlu5 regulates T10-inhibited microglia activation via modulating protein expression of the receptor and its intracellular signaling. The study might contribute to the biological effects of Chinese herbs as an approach for protecting against neurotoxicity in PD.
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Affiliation(s)
- Yi-Ying Huang
- Department of Neurobiology, School of Basic Medical Sciences, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Capital Medical University, Beijing 100069, China
| | - Qian Zhang
- Department of Neurobiology, School of Basic Medical Sciences, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Capital Medical University, Beijing 100069, China
| | - Jian-Nan Zhang
- Department of Neurobiology, School of Basic Medical Sciences, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Capital Medical University, Beijing 100069, China
| | - Ya-Nan Zhang
- Department of Neurobiology, School of Basic Medical Sciences, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Capital Medical University, Beijing 100069, China
| | - Li Gu
- Department of Neurobiology, School of Basic Medical Sciences, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Capital Medical University, Beijing 100069, China
| | - Hui-Min Yang
- Department of Neurobiology, School of Basic Medical Sciences, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Capital Medical University, Beijing 100069, China
| | - Ning Xia
- Burke Medical Research Institute, Weill Cornell Medicine, White Plains, NY, 10605, USA
| | - Xiao-Min Wang
- Department of Neurobiology, School of Basic Medical Sciences, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Capital Medical University, Beijing 100069, China
| | - Hong Zhang
- Department of Neurobiology, School of Basic Medical Sciences, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Capital Medical University, Beijing 100069, China.
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Xia N, Zhang Q, Wang ST, Gu L, Yang HM, Liu L, Bakshi R, Yang H, Zhang H. Blockade of metabotropic glutamate receptor 5 protects against DNA damage in a rotenone-induced Parkinson's disease model. Free Radic Biol Med 2015; 89:567-80. [PMID: 26454081 DOI: 10.1016/j.freeradbiomed.2015.09.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 09/14/2015] [Accepted: 09/15/2015] [Indexed: 12/11/2022]
Abstract
Glutamate excitotoxicity contributes to the development of Parkinson's disease (PD) and pharmacological blockade of metabotropic glutamate receptor 5 (mGluR5) has beneficial anti-akinetic effects in animal models of PD; however, the mechanism by which these antagonists alleviate PD symptoms is largely unknown. In our study, the effects of mGluR5 inhibition on DNA damage were investigated in a rotenone-induced model of PD. We first found that the selective mGluR5 antagonist, 2-methyl-6- (phenylethynyl) pyridine, prevented rotenone-induced DNA damage in MN9D dopaminergic neurons through a mechanism involving the downregulation of intracellular calcium release which was associated with a reduction in endoplasmic reticulum stress and reactive oxygen species (ROS)-related mitochondrial dysfunction. Interestingly, the ROS-related mitochondrial dysfunction was accompanied by an increase in expression of the antioxidant protein, Trx2. Treatment of cells with the calcium chelating agent 1,2-bis-(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid or the ROS scavenger N-acetyl-L-cysteine, also reduced rotenone-induced DNA damage, while transfection of a dominant-negative form of Trx2 increased it. In addition, mGluR5 inhibition altered the expression profiles of proteins involved in DNA repair activity. Specifically, the expression of phosphorylated ERK (p-ERK) and CREB, as well as APE1 and Rad51 were elevated after rotenone stimulation and were subsequently downregulated following blockade of mGluR5. These findings were confirmed in vivo in a rotenone-induced rat model of PD. Inhibition of mGluR5 protected against neurotoxicity by mitigating oxidative stress-related DNA damage associated with 8-hydroxy-2'-deoxyguanosine production and also reduced p-ERK activity and Trx2 expression. These findings provide a novel link between mGluR5 and DNA damage in a model of PD, and reveal a potential mechanism by which mGluR5 mediates DNA damage in neurodegenerative diseases.
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Affiliation(s)
- Ning Xia
- Department of Neurobiology, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Capital Medical University, Beijing 100069, China
| | - Qian Zhang
- Department of Neurobiology, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Capital Medical University, Beijing 100069, China
| | - Shu Ting Wang
- Department of Neurobiology, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Capital Medical University, Beijing 100069, China
| | - Li Gu
- Department of Neurobiology, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Capital Medical University, Beijing 100069, China
| | - Hui Min Yang
- Department of Neurobiology, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Capital Medical University, Beijing 100069, China
| | - Li Liu
- Department of Neurobiology, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Capital Medical University, Beijing 100069, China
| | - Rachit Bakshi
- Department of Neurology, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Boston, MA 02129
| | - Hui Yang
- Department of Neurobiology, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Capital Medical University, Beijing 100069, China
| | - Hong Zhang
- Department of Neurobiology, Beijing Institute for Brain Disorders and Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Capital Medical University, Beijing 100069, China.
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D'Antoni S, Berretta A, Seminara G, Longone P, Giuffrida-Stella AM, Battaglia G, Sortino MA, Nicoletti F, Catania MV. A prolonged pharmacological blockade of type-5 metabotropic glutamate receptors protects cultured spinal cord motor neurons against excitotoxic death. Neurobiol Dis 2011; 42:252-64. [DOI: 10.1016/j.nbd.2011.01.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 12/24/2010] [Accepted: 01/03/2011] [Indexed: 01/23/2023] Open
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Iwagaki N, Miles GB. Activation of group I metabotropic glutamate receptors modulates locomotor-related motoneuron output in mice. J Neurophysiol 2011; 105:2108-20. [PMID: 21346211 DOI: 10.1152/jn.01037.2010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Fast glutamatergic transmission via ionotropic receptors is critical for the generation of locomotion by spinal motor networks. In addition, glutamate can act via metabotropic glutamate receptors (mGluRs) to modulate the timing of ongoing locomotor activity. In the present study, we investigated whether mGluRs also modulate the intensity of motor output generated by spinal motor networks. Application of the group I mGluR agonist (S)-3,5-dihydroxyphenylglycine (DHPG) reduced the amplitude and increased the frequency of locomotor-related motoneuron output recorded from the lumbar ventral roots of isolated mouse spinal cord preparations. Whole cell patch-clamp recordings of spinal motoneurons revealed multiple mechanisms by which group I mGluRs modulate motoneuron output. Although DHPG depolarized the resting membrane potential and reduced the voltage threshold for action potential generation, the activation of group I mGluRs had a net inhibitory effect on motoneuron output that appeared to reflect the modulation of fast, inactivating Na(+) currents and action potential parameters. In addition, group I mGluR activation decreased the amplitude of locomotor-related excitatory input to motoneurons. Analyses of miniature excitatory postsynaptic currents indicated that mGluRs modulate synaptic drive to motoneurons via both pre- and postsynaptic mechanisms. These data highlight group I mGluRs as a potentially important source of neuromodulation within the spinal cord that, in addition to modulating components of the central pattern generator for locomotion, can modulate the intensity of motoneuron output during motor behavior. Given that group I mGluR activation reduces motoneuron excitability, mGluRs may provide negative feedback control of motoneuron output, particularly during high levels of glutamatergic stimulation.
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Affiliation(s)
- Noboru Iwagaki
- School of Biology, University of St. Andrews, St. Andrews, Fife, United Kingdom
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