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Minhas PS, Jones JR, Latif-Hernandez A, Sugiura Y, Durairaj AS, Uenaka T, Wang Q, Mhatre SD, Liu L, Conley T, Ennerfelt H, Jung YJ, Prasad P, Jenkins BC, Goodman R, Newmeyer T, Heard K, Kang A, Wilson EN, Ullian EM, Serrano GE, Beach TG, Rabinowitz JD, Wernig M, Suematsu M, Longo FM, McReynolds MR, Gage FH, Andreasson KI. Restoring hippocampal glucose metabolism rescues cognition across Alzheimer's disease pathologies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.23.598940. [PMID: 38979192 PMCID: PMC11230169 DOI: 10.1101/2024.06.23.598940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Impaired cerebral glucose metabolism is a pathologic feature of Alzheimer Disease (AD), and recent proteomic studies highlight a disruption of glial carbohydrate metabolism with disease progression. Here, we report that inhibition of indoleamine-2,3-dioxygenase 1 (IDO1), which metabolizes tryptophan to kynurenine (KYN) in the first step of the kynurenine pathway, rescues hippocampal memory function and plasticity in preclinical models of amyloid and tau pathology by restoring astrocytic metabolic support of neurons. Activation of IDO1 in astrocytes by amyloid-beta 42 and tau oligomers, two major pathological effectors in AD, increases KYN and suppresses glycolysis in an AhR-dependent manner. Conversely, pharmacological IDO1 inhibition restores glycolysis and lactate production. In amyloid-producing APP Swe -PS1 ΔE9 and 5XFAD mice and in tau-producing P301S mice, IDO1 inhibition restores spatial memory and improves hippocampal glucose metabolism by metabolomic and MALDI-MS analyses. IDO1 blockade also rescues hippocampal long-term potentiation (LTP) in a monocarboxylate transporter (MCT)-dependent manner, suggesting that IDO1 activity disrupts astrocytic metabolic support of neurons. Indeed, in vitro mass-labeling of human astrocytes demonstrates that IDO1 regulates astrocyte generation of lactate that is then taken up by human neurons. In co-cultures of astrocytes and neurons derived from AD subjects, deficient astrocyte lactate transfer to neurons was corrected by IDO1 inhibition, resulting in improved neuronal glucose metabolism. Thus, IDO1 activity disrupts astrocytic metabolic support of neurons across both amyloid and tau pathologies and in a model of AD iPSC-derived neurons. These findings also suggest that IDO1 inhibitors developed for adjunctive therapy in cancer could be repurposed for treatment of amyloid- and tau-mediated neurodegenerative diseases.
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Ma X, Wang X, Zhu K, Ma R, Chu F, Liu X, Zhang S, Yin T, Zhou X, Liu Z. Study on the Role of Physical Fields in TMAS to Modulate Synaptic Plasticity in Mice. IEEE Trans Biomed Eng 2024; 71:1531-1541. [PMID: 38117631 DOI: 10.1109/tbme.2023.3342012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
OBJECTIVE Transcranial magneto-acoustic stimulation (TMAS) is a composite technique combining static magnetic and coupled electric fields with transcranial ultrasound stimulation (TUS) and has shown advantages in neuromodulation. However, the role of these physical fields in neuromodulation is unclear. Synaptic plasticity is the cellular basis for learning and memory. In this paper, we varied the intensity of static magnetic, electric and ultrasonic fields respectively to investigate the modulation of synaptic plasticity by these physical fields. METHODS There are control, static magnetic field (0.1 T/0.2 T), TUS (0.15/0.3 MPa), and TMAS (0.15 MPa + 0.2 V/m, 0.3 MPa + 0.2 V/m, 0.3 MPa + 0.4 V/m) groups. Hippocampal areas were stimulated at 5 min daily for 7 days and in vivo electrophysiological experiments were performed. RESULTS TMAS induced greater LTP, LTD, and paired-pulse ratio (PPR) than TUS, reflecting that TMAS has a more significant modulation in both long- and short- term synaptic plasticity. In TMAS, a doubling of the electric field amplitude increases LTP, LTD and PPR to a greater extent than a doubling of the acoustic pressure. Increasing the static magnetic field intensity has no significant effect on the modulation of synaptic plasticity. CONCLUSION This paper argues that electric fields should be the main reason for the difference in modulation between TMAS and TUS and that changing the amplitude of the electric field affected the modulation of TMAS more than changing the acoustic pressure. SIGNIFICANCE This study elucidates the roles of the physical fields in TMAS and provides a parameterisation way to guide TMAS applications based on the dominant roles of the physical fields.
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Casagrande S, Zuliani L, Grisold W. Paraneoplastic encephalitis. HANDBOOK OF CLINICAL NEUROLOGY 2024; 200:131-149. [PMID: 38494274 DOI: 10.1016/b978-0-12-823912-4.00019-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
The first reports of encephalitis associated with cancer date to the 1960s and were characterized by clinical and pathologic involvement of limbic areas. This specific association was called limbic encephalitis (LE). The subsequent discovery of several "onconeural" antibodies (Abs), i.e., Abs targeting an antigen shared by neurons and tumor cells, supported the hypothesis of an autoimmune paraneoplastic etiology of LE and other forms of rapidly progressive encephalopathy. Over the past 20 years, similar clinical pictures with different clinical courses have been described in association with novel Abs-binding neuronal membrane proteins and proved to be pathogenic. The most well-known encephalitis in this group was described in 2007 as an association of a complex neuro-psychiatric syndrome, N-methyl-d-aspartate (NMDA) receptor-Abs, and ovarian teratoma in young women. Later on, nonparaneoplastic cases of NMDA receptor encephalitis were also described. Since then, the historical concept of LE and Ab associated encephalitis has changed. Some of these occur in fact more commonly in the absence of a malignancy (e.g., anti-LG1 Abs). Lastly, seronegative cases were also described. The term paraneoplastic encephalitis nowadays encompasses different syndromes that may be triggered by occult tumors.
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Affiliation(s)
- Silvia Casagrande
- Neurology Unit, Rovereto Hospital, Trento, Italy; Department of Neurosciences, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy.
| | - Luigi Zuliani
- Department of Neurology, San Bortolo Hospital, Azienda ULSS8 Berica, Vicenza, Italy
| | - Wolfgang Grisold
- Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Vienna, Austria
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Effects of Dietary n-3 LCPUFA Supplementation on the Hippocampus of Aging Female Mice: Impact on Memory, Lipid Raft-Associated Glutamatergic Receptors and Neuroinflammation. Int J Mol Sci 2022; 23:ijms23137430. [PMID: 35806435 PMCID: PMC9267073 DOI: 10.3390/ijms23137430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 06/29/2022] [Accepted: 07/02/2022] [Indexed: 11/17/2022] Open
Abstract
Long-chain polyunsaturated fatty acids (LCPUFA), essential molecules whose precursors must be dietary supplied, are highly represented in the brain contributing to numerous neuronal processes. Recent findings have demonstrated that LCPUFA are represented in lipid raft microstructures, where they favor molecular interactions of signaling complexes underlying neuronal functionality. During aging, the brain lipid composition changes affecting the lipid rafts’ integrity and protein signaling, which may induce memory detriment. We investigated the effect of a n-3 LCPUFA-enriched diet on the cognitive function of 6- and 15-months-old female mice. Likewise, we explored the impact of dietary n-3 LCPUFAs on hippocampal lipid rafts, and their potential correlation with aging-induced neuroinflammation. Our results demonstrate that n-3 LCPUFA supplementation improves spatial and recognition memory and restores the expression of glutamate and estrogen receptors in the hippocampal lipid rafts of aged mice to similar profiles than young ones. Additionally, the n-3 LCPUFA-enriched diet stabilized the lipid composition of the old mice’s hippocampal lipid rafts to the levels of young ones and reduced the aged-induced neuroinflammatory markers. Hence, we propose that n-3 LCPUFA supplementation leads to beneficial cognitive performance by “rejuvenating” the lipid raft microenvironment that stabilizes the integrity and interactions of memory protein players embedded in these microdomains.
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de Souza JM, Ferreira-Vieira TH, Maciel EMA, Silva NC, Lima IBQ, Doria JG, Olmo IG, Ribeiro FM. mGluR5 ablation leads to age-related synaptic plasticity impairments and does not improve Huntington’s disease phenotype. Sci Rep 2022; 12:8982. [PMID: 35643779 PMCID: PMC9148310 DOI: 10.1038/s41598-022-13029-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 05/18/2022] [Indexed: 11/29/2022] Open
Abstract
Glutamate receptors, including mGluR5, are involved in learning and memory impairments triggered by aging and neurological diseases. However, each condition involves distinct molecular mechanisms. It is still unclear whether the mGluR5 cell signaling pathways involved in normal brain aging differ from those altered due to neurodegenerative disorders. Here, we employed wild type (WT), mGluR5−/−, BACHD, which is a mouse model of Huntington’s Disease (HD), and mGluR5−/−/BACHD mice, at the ages of 2, 6 and 12 months, to distinguish the mGluR5-dependent cell signaling pathways involved in aging and neurodegenerative diseases. We demonstrated that the memory impairment exhibited by mGluR5−/− mice is accompanied by massive neuronal loss and decreased dendritic spine density in the hippocampus, similarly to BACHD and BACHD/mGluR5−/− mice. Moreover, mGluR5 ablation worsens some of the HD-related alterations. We also show that mGluR5−/− and BACHD/mGluR5−/− mice have decreased levels of PSD95, BDNF, and Arc/Arg3.1, whereas BACHD mice are mostly spared. PSD95 expression was affected exclusively by mGluR5 ablation in the aging context, making it a potential target to treat age-related alterations. Taken together, we reaffirm the relevance of mGluR5 for memory and distinguish the mGluR5 cell signaling pathways involved in normal brain aging from those implicated in HD.
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Ghasemi Z, Naderi N, Shojaei A, Raoufy MR, Ahmadirad N, Barkley V, Mirnajafi-Zadeh J. Group I metabotropic glutamate receptors contribute to the antiepileptic effect of electrical stimulation in hippocampal CA1 pyramidal neurons. Epilepsy Res 2021; 178:106821. [PMID: 34839145 DOI: 10.1016/j.eplepsyres.2021.106821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 11/04/2021] [Accepted: 11/16/2021] [Indexed: 11/17/2022]
Abstract
Low-frequency deep brain stimulation (LFS) inhibits neuronal hyperexcitability during epilepsy. Accordingly, the use of LFS as a treatment method for patients with drug-resistant epilepsy has been proposed. However, the LFS antiepileptic mechanisms are not fully understood. Here, the role of metabotropic glutamate receptors group I (mGluR I) in LFS inhibitory action on epileptiform activity (EA) was investigated. EA was induced by increasing the K+ concentration in artificial cerebrospinal fluid (ACSF) up to 12 mM in hippocampal slices of male Wistar rats. LFS (1 Hz, 900 pulses) was delivered to the bundles of Schaffer collaterals at the beginning of EA. The excitability of CA1 pyramidal neurons was assayed by intracellular whole-cell recording. Applying LFS reduced the firing frequency during EA and substantially moved the membrane potential toward repolarization after a high-K+ ACSF washout. In addition, LFS attenuated the EA-generated neuronal hyperexcitability. A blockade of both mGluR 1 and mGluR 5 prevented the inhibitory action of LFS on EA-generated neuronal hyperexcitability. Activation of mGluR I mimicked the LFS effects and had similar inhibitory action on excitability of CA1 pyramidal neurons following EA. However, mGluR I agonist's antiepileptic action was not as strong as LFS. The observed LFS effects were significantly attenuated in the presence of a PKC inhibitor. Altogether, the LFS' inhibitory action on neuronal hyperexcitability following EA relies, in part, on the activity of mGluR I and a PKC-related signaling pathway.
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Affiliation(s)
- Zahra Ghasemi
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
| | - Nima Naderi
- Department of Pharmacology and Toxicology, School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Shojaei
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mohammad Reza Raoufy
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Nooshin Ahmadirad
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Victoria Barkley
- Krembil Research Institute, University Health Network, Toronto, Canada
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; Institute for Brain Sciences and Cognition, Tarbiat Modares University, Tehran, Iran.
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Minhas PS, Latif-Hernandez A, McReynolds MR, Durairaj AS, Wang Q, Rubin A, Joshi AU, He JQ, Gauba E, Liu L, Wang C, Linde M, Sugiura Y, Moon PK, Majeti R, Suematsu M, Mochly-Rosen D, Weissman IL, Longo FM, Rabinowitz JD, Andreasson KI. Restoring metabolism of myeloid cells reverses cognitive decline in ageing. Nature 2021; 590:122-128. [PMID: 33473210 PMCID: PMC8274816 DOI: 10.1038/s41586-020-03160-0] [Citation(s) in RCA: 228] [Impact Index Per Article: 76.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 12/08/2020] [Indexed: 01/30/2023]
Abstract
Ageing is characterized by the development of persistent pro-inflammatory responses that contribute to atherosclerosis, metabolic syndrome, cancer and frailty1-3. The ageing brain is also vulnerable to inflammation, as demonstrated by the high prevalence of age-associated cognitive decline and Alzheimer's disease4-6. Systemically, circulating pro-inflammatory factors can promote cognitive decline7,8, and in the brain, microglia lose the ability to clear misfolded proteins that are associated with neurodegeneration9,10. However, the underlying mechanisms that initiate and sustain maladaptive inflammation with ageing are not well defined. Here we show that in ageing mice myeloid cell bioenergetics are suppressed in response to increased signalling by the lipid messenger prostaglandin E2 (PGE2), a major modulator of inflammation11. In ageing macrophages and microglia, PGE2 signalling through its EP2 receptor promotes the sequestration of glucose into glycogen, reducing glucose flux and mitochondrial respiration. This energy-deficient state, which drives maladaptive pro-inflammatory responses, is further augmented by a dependence of aged myeloid cells on glucose as a principal fuel source. In aged mice, inhibition of myeloid EP2 signalling rejuvenates cellular bioenergetics, systemic and brain inflammatory states, hippocampal synaptic plasticity and spatial memory. Moreover, blockade of peripheral myeloid EP2 signalling is sufficient to restore cognition in aged mice. Our study suggests that cognitive ageing is not a static or irrevocable condition but can be reversed by reprogramming myeloid glucose metabolism to restore youthful immune functions.
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Affiliation(s)
- Paras S. Minhas
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.,Neurosciences Graduate Program, Stanford University, Stanford, CA, USA.,Medical Scientist Training Program, Stanford University, Stanford, CA, USA
| | - Amira Latif-Hernandez
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.,These authors contributed equally: Amira Latif-Hernandez, Melanie R. McReynolds
| | - Melanie R. McReynolds
- Department of Chemistry, Princeton University, Princeton, NJ, USA.,Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.,These authors contributed equally: Amira Latif-Hernandez, Melanie R. McReynolds
| | - Aarooran S. Durairaj
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Qian Wang
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Amanda Rubin
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.,Neurosciences Graduate Program, Stanford University, Stanford, CA, USA
| | - Amit U. Joshi
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Joy Q. He
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Esha Gauba
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Ling Liu
- Department of Chemistry, Princeton University, Princeton, NJ, USA.,Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Congcong Wang
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Miles Linde
- Department of Hematology, Stanford University School of Medicine, Stanford, CA, USA
| | - Yuki Sugiura
- Department of Biochemistry, Keio University School of Medicine, Tokyo, Japan
| | - Peter K. Moon
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Ravi Majeti
- Department of Hematology, Stanford University School of Medicine, Stanford, CA, USA
| | - Makoto Suematsu
- Department of Biochemistry, Keio University School of Medicine, Tokyo, Japan
| | - Daria Mochly-Rosen
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA
| | - Irving L. Weissman
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Frank M. Longo
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Joshua D. Rabinowitz
- Department of Chemistry, Princeton University, Princeton, NJ, USA.,Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Katrin I. Andreasson
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA, USA.,Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA.,Stanford Immunology Program, Stanford University, Stanford, CA, USA.,Correspondence and requests for materials should be addressed to K.I.A.
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8
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Faldini E, Ahmed T, Bueé L, Blum D, Balschun D. Tau- but not Aß -pathology enhances NMDAR-dependent depotentiation in AD-mouse models. Acta Neuropathol Commun 2019; 7:202. [PMID: 31815648 PMCID: PMC6902514 DOI: 10.1186/s40478-019-0813-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 09/22/2019] [Indexed: 11/10/2022] Open
Abstract
Many mouse models of Alzheimer's disease (AD) exhibit impairments in hippocampal long-term-potentiation (LTP), seemingly corroborating the strong correlation between synaptic loss and cognitive decline reported in human studies. In other AD mouse models LTP is unaffected, but other defects in synaptic plasticity may still be present. We recently reported that THY-Tau22 transgenic mice, that overexpress human Tau protein carrying P301S and G272 V mutations and show normal LTP upon high-frequency-stimulation (HFS), develop severe changes in NMDAR mediated long-term-depression (LTD), the physiological counterpart of LTP. In the present study, we focused on putative effects of AD-related pathologies on depotentiation (DP), another form of synaptic plasticity. Using a novel protocol to induce DP in the CA1-region, we found in 11-15 months old male THY-Tau22 and APPPS1-21 transgenic mice that DP was not deteriorated by Aß pathology while significantly compromised by Tau pathology. Our findings advocate DP as a complementary form of synaptic plasticity that may help in elucidating synaptic pathomechanisms associated with different types of dementia.
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Chen ANY, Hellyer SD, Trinh PNH, Leach K, Gregory KJ. Identification of monellin as the first naturally derived proteinaceous allosteric agonist of metabotropic glutamate receptor 5. Basic Clin Pharmacol Toxicol 2019; 126 Suppl 6:104-115. [DOI: 10.1111/bcpt.13239] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 04/10/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Amy N. Y. Chen
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology Monash University Parkville Victoria Australia
| | - Shane D. Hellyer
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology Monash University Parkville Victoria Australia
| | - Phuc N. H. Trinh
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology Monash University Parkville Victoria Australia
| | - Katie Leach
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology Monash University Parkville Victoria Australia
| | - Karen J. Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology Monash University Parkville Victoria Australia
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10
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Sengmany K, Hellyer SD, Albold S, Wang T, Conn PJ, May LT, Christopoulos A, Leach K, Gregory KJ. Kinetic and system bias as drivers of metabotropic glutamate receptor 5 allosteric modulator pharmacology. Neuropharmacology 2019; 149:83-96. [PMID: 30763654 DOI: 10.1016/j.neuropharm.2019.02.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 01/18/2019] [Accepted: 02/04/2019] [Indexed: 12/17/2022]
Abstract
Allosteric modulators of the metabotropic glutamate receptor subtype 5 (mGlu5) have been proposed as potential therapies for various CNS disorders. These ligands bind to sites distinct from the orthosteric (or endogenous) ligand, often with improved subtype selectivity and spatio-temporal control over receptor responses. We recently revealed that mGlu5 allosteric agonists and positive allosteric modulators exhibit biased agonism and/or modulation. To establish whether negative allosteric modulators (NAMs) engender similar bias, we rigorously characterized the pharmacology of eight diverse mGlu5 NAMs. Radioligand inhibition binding studies revealed novel modes of interaction with mGlu5 for select NAMs, with biphasic or incomplete inhibition of the radiolabeled NAM, [3H]methoxy-PEPy. We assessed mGlu5-mediated intracellular Ca2+ (iCa2+) mobilization and inositol phosphate (IP1) accumulation in HEK293A cells stably expressing low levels of mGlu5 (HEK293A-rat mGlu5-low) and mouse embryonic cortical neurons. The apparent affinity of acetylenic NAMs, MPEP, MTEP and dipraglurant, was dependent on the signaling pathway measured, agonist used, and cell type (HEK293A-rat mGlu5-low versus mouse cortical neurons). In contrast, the acetylenic partial NAM, M-5MPEP, and structurally distinct NAMs (VU0366248, VU0366058, fenobam), had similar affinity estimates irrespective of the assay or cellular background. Biased modulation was evident for VU0366248 in mouse cortical neurons where it was a NAM for DHPG-mediated iCa2+ mobilization, but neutral with DHPG in IP1 accumulation assays. Overall, this study highlights the inherent complexity in mGlu5 NAM pharmacology that we hypothesize may influence interpretation when translating into preclinical models and beyond in the design and development of novel therapeutics for neuropsychiatric and neurological disorders.
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Affiliation(s)
- Kathy Sengmany
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - Shane D Hellyer
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - Sabine Albold
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - Taide Wang
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - P Jeffrey Conn
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Lauren T May
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - Arthur Christopoulos
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - Katie Leach
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia
| | - Karen J Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Department of Pharmacology, Monash University, Parkville, VIC, Australia.
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11
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Montes de Oca Balderas P. Flux-Independent NMDAR Signaling: Molecular Mediators, Cellular Functions, and Complexities. Int J Mol Sci 2018; 19:ijms19123800. [PMID: 30501045 PMCID: PMC6321296 DOI: 10.3390/ijms19123800] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 11/16/2018] [Accepted: 11/19/2018] [Indexed: 12/21/2022] Open
Abstract
The glutamate (Glu) N-methyl-d-aspartate (NMDA) receptor (NMDAR) plays a critical role in synaptic communication given mainly by its ionotropic function that permeates Ca2+. This in turn activates calmodulin that triggers CaMKII, MAPK, CREB, and PI3K pathways, among others. However, NMDAR signaling is more complex. In the last two decades several groups have shown that the NMDAR also elicits flux-independent signaling (f-iNMDARs). It has been demonstrated that agonist (Glu or NMDA) or co-agonist (Glycine or d-Serine) bindings initiate intracellular events, including conformational changes, exchange of molecular interactions, release of second messengers, and signal transduction, that result in different cellular events including endocytosis, LTD, cell death, and neuroprotection, among others. Interestingly, f-iNMDARs has also been observed in pathological conditions and non-neuronal cells. Here, the molecular and cellular events elicited by these flux-independent actions (non-canonical or metabotropic-like) of the NMDAR are reviewed. Considering the NMDAR complexity, it is possible that these flux-independent events have a more relevant role in intracellular signaling that has been disregarded for decades. Moreover, considering the wide expression and function of the NMDAR in non-neuronal cells and other tissues beyond the nervous system and some evolutionary traits, f-iNMDARs calls for a reconsideration of how we understand the biology of this complex receptor.
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Affiliation(s)
- Pavel Montes de Oca Balderas
- Departamento de Neurociencia Cognitiva, Instituto de Fisiología Celular, UNAM. Av. Universidad 3000, C.U. Coyoacán, Ciudad de México. C.P. 04510, Mexico.
- Unidad de Neurobiología Dinámica, Departamento de Neuroquímica, INNN. Av. Insurgentes Sur #3877 Col. La Fama, Ciudad de México. C.P. 14269, Mexico.
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12
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Long Term Depression in Rat Hippocampus and the Effect of Ethanol during Fetal Life. Brain Sci 2017; 7:brainsci7120157. [PMID: 29182556 PMCID: PMC5742760 DOI: 10.3390/brainsci7120157] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 11/20/2017] [Accepted: 11/27/2017] [Indexed: 12/11/2022] Open
Abstract
Alcohol (ethanol) disturbs cognitive functions including learning and memory in humans, non-human primates, and laboratory animals such as rodents. As studied in animals, cellular mechanisms for learning and memory include bidirectional synaptic plasticity, long-term potentiation (LTP), and long-term depression (LTD), primarily in the hippocampus. Most of the research in the field of alcohol has analyzed the effects of ethanol on LTP; however, with recent advances in the understanding of the physiological role of LTD in learning and memory, some authors have examined the effects of ethanol exposure on this particular signal. In the present review, I will focus on hippocampal LTD recorded in rodents and the effects of fetal alcohol exposure on this signal. A synthesis of the findings indicates that prenatal ethanol exposure disturbs LTD concurrently with LTP in offspring and that both glutamatergic and γ-aminobutyric acid (GABA) neurotransmissions are altered and contribute to LTD disturbances. Although the ultimate mode of action of ethanol on these two transmitter systems is not yet clear, novel suggestions have recently appeared in the literature.
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13
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Unconventional NMDA Receptor Signaling. J Neurosci 2017; 37:10800-10807. [PMID: 29118208 DOI: 10.1523/jneurosci.1825-17.2017] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/28/2017] [Accepted: 09/28/2017] [Indexed: 11/21/2022] Open
Abstract
In the classical view, NMDA receptors (NMDARs) are stably expressed at the postsynaptic membrane, where they act via Ca2+ to signal coincidence detection in Hebbian plasticity. More recently, it has been established that NMDAR-mediated transmission can be dynamically regulated by neural activity. In addition, NMDARs have been found presynaptically, where they cannot act as conventional coincidence detectors. Unexpectedly, NMDARs have also been shown to signal metabotropically, without the need for Ca2+ This review highlights novel findings concerning these unconventional modes of NMDAR action.
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Xiang Q, Li XH, Yang B, Fang XX, Jia J, Ren J, Dong YC, Ou-Yang C, Wang GC. Allicin attenuates tunicamycin-induced cognitive deficits in rats via its synaptic plasticity regulatory activity. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2017; 20:676-682. [PMID: 28868122 PMCID: PMC5569445 DOI: 10.22038/ijbms.2017.8837] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Objective(s): To illuminate the functional effects of allicin on rats with cognitive deficits induced by tunicamycin (TM) and the molecular mechanism of this process. Materials and Methods: 200–250 g male SD rats were divided into three groups at random: control group (n=12), TM group (5 μl, 50 μM, ICV, n=12), and allicin treatment group (180 mg/kg/d with chow diet, n=12). After 16 weeks of allicin treatment, the learning ability and memory were tested using novel object recognition (NOR) testing on rats with 72 hr TM treatment (5 μl, 50 μM, ICV); meanwhile, the variation of field excitatory postsynaptic potential (fEPSP) in the Schaffer Collateral (SC)-CA1 synapse was detected by extracellular electrophysiological recordings and the morphology of dendritic spine was observed by Golgi staining as well as detecting several synaptic plasticity-related proteins by Western blot. Results: The density of dendritic spine was increased significantly in allicin-treated groups and the correspondence slope of fEPSP in TM-induced cognitive deficits group was enhanced and expression of synaptophysin and glutamate receptor-1(GluR1) in hippocampal neurons was up-regulated. Conclusion: The results indicate that allicin plays an important role in synaptic plasticity regulation. These finding showed that allicin could be used as a pharmacologic treatment in TM-induced cognitive deficits.
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Affiliation(s)
- Qiong Xiang
- Institute of Medicine, Medical Research Center, Jishou University, Hunan, China
| | - Xian-Hui Li
- Institute of Medicine, Medical Research Center, Jishou University, Hunan, China
| | - Bo Yang
- Jishou University First Affiliated Hospital, Jishou University, Hunan, China
| | - Xin-Xing Fang
- Institute of Medicine, Medical Research Center, Jishou University, Hunan, China
| | - Jing Jia
- Institute of Medicine, Medical Research Center, Jishou University, Hunan, China
| | - Jie Ren
- Institute of Medicine, Medical Research Center, Jishou University, Hunan, China
| | - Yu-Chun Dong
- Institute of Medicine, Medical Research Center, Jishou University, Hunan, China
| | - Cheng Ou-Yang
- Institute of Medicine, Medical Research Center, Jishou University, Hunan, China
| | - Guang-Cheng Wang
- College of Chemistry and Chemical Engineering, Jishou University, Hunan, China
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