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Davoody S, Asgari Taei A, Khodabakhsh P, Dargahi L. mTOR signaling and Alzheimer's disease: What we know and where we are? CNS Neurosci Ther 2024; 30:e14463. [PMID: 37721413 PMCID: PMC11017461 DOI: 10.1111/cns.14463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/19/2023] Open
Abstract
Despite the great body of research done on Alzheimer's disease, the underlying mechanisms have not been vividly investigated. To date, the accumulation of amyloid-beta plaques and tau tangles constitutes the hallmark of the disease; however, dysregulation of the mammalian target of rapamycin (mTOR) seems to be significantly involved in the pathogenesis of the disease as well. mTOR, as a serine-threonine protein kinase, was previously known for controlling many cellular functions such as cell size, autophagy, and metabolism. In this regard, mammalian target of rapamycin complex 1 (mTORC1) may leave anti-aging impacts by robustly inhibiting autophagy, a mechanism that inhibits the accumulation of damaged protein aggregate and dysfunctional organelles. Formation and aggregation of neurofibrillary tangles and amyloid-beta plaques seem to be significantly regulated by mTOR signaling. Understanding the underlying mechanisms and connection between mTOR signaling and AD may suggest conducting clinical trials assessing the efficacy of rapamycin, as an mTOR inhibitor drug, in managing AD or may help develop other medications. In this literature review, we aim to elaborate mTOR signaling network mainly in the brain, point to gaps of knowledge, and define how and in which ways mTOR signaling can be connected with AD pathogenesis and symptoms.
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Affiliation(s)
- Samin Davoody
- Student Research Committee, School of MedicineShahid Beheshti University of Medical SciencesTehranIran
| | - Afsaneh Asgari Taei
- Neuroscience Research CenterShahid Beheshti University of Medical SciencesTehranIran
| | - Pariya Khodabakhsh
- Department of NeurophysiologyInstitute of Physiology, Eberhard Karls University of TübingenTübingenGermany
| | - Leila Dargahi
- Neurobiology Research CenterShahid Beheshti University of Medical SciencesTehranIran
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MacCallum PE, Cooze JB, Ward J, Moore KA, Blundell J. Evaluating the effects of single, multiple, and delayed systemic rapamycin injections to contextual fear reconsolidation: Implications for the neurobiology of memory and the treatment of PTSD-like re-experiencing. Behav Brain Res 2024; 461:114855. [PMID: 38185381 DOI: 10.1016/j.bbr.2024.114855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 12/18/2023] [Accepted: 01/03/2024] [Indexed: 01/09/2024]
Abstract
The mechanistic target of rapamycin (mTOR) kinase is known to mediate the formation and persistence of aversive memories. Rapamycin, an mTOR inhibitor, administered around the time of reactivation blocks retrieval-induced mTOR activity and de novo protein synthesis in the brains of rodents, while correspondingly diminishing subsequent fear memory. The goal of the current experiments was to further explore rapamycin's effects on fear memory persistence. First, we examined whether mTOR blockade at different time-points after reactivation attenuates subsequent contextual fear memory. We show that rapamycin treatment 3 or 12 h post-reactivation disrupts memory persistence. Second, we examined whether consecutive days of reactivation paired with rapamycin had additive effects over a single pairing at disrupting a contextual fear memory. We show that additional reactivation-rapamycin pairings exacerbates the reconsolidation impairment. Finally, we examined if impaired reconsolidation of a contextual fear memory from rapamycin treatment had any after-effects on learning and recalling a new fear association. We show that rapamycin-impaired reconsolidation does not affect new learning or recall and protects against fear generalization. Our findings improve our understanding of mTOR- dependent fear memory processes, as well as provide insight into potentially novel treatment options for stress-related psychopathologies such as posttraumatic stress disorder.
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Affiliation(s)
- Phillip E MacCallum
- Department of Psychology, Memorial University of Newfoundland, 232 Elizabeth Ave, St. John's, Newfoundland and Labrador A1B 3X9, Canada
| | - Jane B Cooze
- Department of Psychology, Memorial University of Newfoundland, 232 Elizabeth Ave, St. John's, Newfoundland and Labrador A1B 3X9, Canada
| | - Joshua Ward
- Department of Psychology, Memorial University of Newfoundland, 232 Elizabeth Ave, St. John's, Newfoundland and Labrador A1B 3X9, Canada
| | - Kelsey Am Moore
- Department of Psychology, Memorial University of Newfoundland, 232 Elizabeth Ave, St. John's, Newfoundland and Labrador A1B 3X9, Canada
| | - Jacqueline Blundell
- Department of Psychology, Memorial University of Newfoundland, 232 Elizabeth Ave, St. John's, Newfoundland and Labrador A1B 3X9, Canada.
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Trask J, MacCallum PE, Rideout H, Preisser EL, Blundell JJ. Rapamycin attenuates reconsolidation of a backwards-conditioned aversive stimuli in female mice. Psychopharmacology (Berl) 2024; 241:601-612. [PMID: 38311691 DOI: 10.1007/s00213-024-06544-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 01/20/2024] [Indexed: 02/06/2024]
Abstract
RATIONALE The mammalian target of rapamycin (mTOR) kinase is known to mediate consolidation and reconsolidation of aversive memories. Most studies in this area use a forward conditioning paradigm in which the conditioned stimulus (CS) precedes the unconditioned stimulus (US). Little is known, however, about the neurobiological underpinnings of backwards (BW) conditioning paradigms, particularly in female mice. In BW conditioning, the CS does not become directly associated with the US; it instead evokes conditioned fear by reactivating a memory of the conditioning context and indirectly retrieving a memory of the aversive US. OBJECTIVES We sought to examine BW conditioned fear memory processes in female mice. First, we examined whether freezing to a BW CS is mediated by fear to the conditioning context. Second, we tested whether blocking consolidation of a BW CS attenuated memory of the CS and conditioning context. Finally, we tested whether blocking reconsolidation of a BW CS attenuated memory of the conditioning context. RESULTS We show that conditioned freezing to a BW CS is mediated by fear to the conditioning context. Furthermore, rapamycin-an mTOR inhibitor, when given immediately following BW conditioning, impairs consolidation of both cued and contextual fear memory. Similarly, rapamycin given following retrieval of a BW CS blocks context recall. Rapamycin is acting on reconsolidation as CS retrieval is necessary to see the effects of rapamycin on context memory recall. CONCLUSIONS Our study provides novel evidence that indirect retrieval cues are sensitive to rapamycin in female mice. The capacity to indirectly reactivate memories and render them susceptible to disruption is critical in the translation of reconsolidation-based approaches to the clinic.
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Affiliation(s)
- Jared Trask
- Department of Psychology, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada
| | - Phillip E MacCallum
- Department of Psychology, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada
| | - Haley Rideout
- Department of Psychology, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada
| | - Evan L Preisser
- Department of Biological Sciences, University of Rhode Island, Kingston, RI, 02881, USA
| | - Jacqueline J Blundell
- Department of Psychology, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada.
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Kim D, Jung H, Shirai Y, Kim H, Kim J, Lim D, Mori T, Lee H, Park D, Kim HY, Guo Q, Pang B, Qiu W, Cao X, Kouyama-Suzuki E, Uemura T, Kasem E, Fu Y, Kim S, Tokunaga A, Yoshizawa T, Suzuki T, Sakagami H, Lee KJ, Ko J, Tabuchi K, Um JW. IQSEC3 Deletion Impairs Fear Memory Through Upregulation of Ribosomal S6K1 Signaling in the Hippocampus. Biol Psychiatry 2022; 91:821-831. [PMID: 35219498 DOI: 10.1016/j.biopsych.2021.12.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/29/2021] [Accepted: 12/15/2021] [Indexed: 12/11/2022]
Abstract
BACKGROUND IQSEC3, a gephyrin-binding GABAergic (gamma-aminobutyric acidergic) synapse-specific guanine nucleotide exchange factor, was recently reported to regulate activity-dependent GABAergic synapse maturation, but the underlying signaling mechanisms remain incompletely understood. METHODS We generated mice with conditional knockout (cKO) of Iqsec3 to examine whether altered synaptic inhibition influences hippocampus-dependent fear memory formation. In addition, electrophysiological recordings, immunohistochemistry, and behavioral assays were used to address our question. RESULTS We found that Iqsec3-cKO induces a specific reduction in GABAergic synapse density, GABAergic synaptic transmission, and maintenance of long-term potentiation in the hippocampal CA1 region. In addition, Iqsec3-cKO mice exhibited impaired fear memory formation. Strikingly, Iqsec3-cKO caused abnormally enhanced activation of ribosomal P70-S6K1-mediated signaling in the hippocampus but not in the cortex. Furthermore, inhibiting upregulated S6K1 signaling by expressing dominant-negative S6K1 in the hippocampal CA1 of Iqsec3-cKO mice completely rescued impaired fear learning and inhibitory synapse density but not deficits in long-term potentiation maintenance. Finally, upregulated S6K1 signaling was rescued by IQSEC3 wild-type, but not by an ARF-GEF (adenosine diphosphate ribosylation factor-guanine nucleotide exchange factor) inactive IQSEC3 mutant. CONCLUSIONS Our results suggest that IQSEC3-mediated balanced synaptic inhibition in hippocampal CA1 is critical for the proper formation of hippocampus-dependent fear memory.
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Affiliation(s)
- Dongwook Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Hyeji Jung
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Yoshinori Shirai
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Hyeonho Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Jinhu Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Dongseok Lim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Takuma Mori
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan; Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Nagano, Japan
| | - Hyojeong Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Dongseok Park
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Hee Young Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Qi Guo
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Bo Pang
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Wen Qiu
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Xueshan Cao
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Emi Kouyama-Suzuki
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Takeshi Uemura
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Enas Kasem
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan; Department of Zoology, Faculty of Science, Kafrelsheikh University, Kafr el-Sheikh, Egypt
| | - Yu Fu
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Seungjoon Kim
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Akinori Tokunaga
- Division of Laboratory Animal Resources, Life Science Research Laboratory, University of Fukui, Fukui, Japan
| | - Takahiro Yoshizawa
- Research Center for Supports to Advanced Science, Shinshu University, Nagano, Japan
| | - Tatsuo Suzuki
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan
| | - Hiroyuki Sakagami
- Department of Anatomy, Kitasato University School of Medicine, Kanagawa, Japan
| | - Kea Joo Lee
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea; Neural Circuits Research Group, Korea Brain Research Institute, Daegu, South Korea
| | - Jaewon Ko
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Katsuhiko Tabuchi
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano, Japan; Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Nagano, Japan.
| | - Ji Won Um
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea.
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Raut SB, Marathe PA, van Eijk L, Eri R, Ravindran M, Benedek DM, Ursano RJ, Canales JJ, Johnson LR. Diverse therapeutic developments for post-traumatic stress disorder (PTSD) indicate common mechanisms of memory modulation. Pharmacol Ther 2022; 239:108195. [PMID: 35489438 DOI: 10.1016/j.pharmthera.2022.108195] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 12/20/2022]
Abstract
Post-traumatic stress disorder (PTSD), characterized by abnormally persistent and distressing memories, is a chronic debilitating condition in need of new treatment options. Current treatment guidelines recommend psychotherapy as first line management with only two drugs, sertraline and paroxetine, approved by U.S. Food and Drug Administration (FDA) for treatment of PTSD. These drugs have limited efficacy as they only reduce symptoms related to depression and anxiety without producing permanent remission. PTSD remains a significant public health problem with high morbidity and mortality requiring major advances in therapeutics. Early evidence has emerged for the beneficial effects of psychedelics particularly in combination with psychotherapy for management of PTSD, including psilocybin, MDMA, LSD, cannabinoids, ayahuasca and ketamine. MDMA and psilocybin reduce barrier to therapy by increasing trust between therapist and patient, thus allowing for modification of trauma related memories. Furthermore, research into the memory reconsolidation mechanisms has allowed for identification of various pharmacological targets to disrupt abnormally persistent memories. A number of pre-clinical and clinical studies have investigated novel and re-purposed pharmacological agents to disrupt fear memory in PTSD. Novel therapeutic approaches like neuropeptide Y, oxytocin, cannabinoids and neuroactive steroids have also shown potential for PTSD treatment. Here, we focus on the role of fear memory in the pathophysiology of PTSD and propose that many of these new therapeutic strategies produce benefits through the effect on fear memory. Evaluation of recent research findings suggests that while a number of drugs have shown promising results in preclinical studies and pilot clinical trials, the evidence from large scale clinical trials would be needed for these drugs to be incorporated in clinical practice.
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Affiliation(s)
- Sanket B Raut
- Schools of Psychological Sciences, College of Health and Medicine, University of Tasmania, TAS 7250, Australia
| | - Padmaja A Marathe
- Department of Pharmacology and Therapeutics, Seth GS Medical College & KEM Hospital, Parel, Mumbai 400 012, India
| | - Liza van Eijk
- Department of Psychology, College of Healthcare Sciences, James Cook University, QLD 4811, Australia
| | - Rajaraman Eri
- Health Sciences, College of Health and Medicine, University of Tasmania, TAS 7250, Australia
| | - Manoj Ravindran
- Medicine, College of Health and Medicine, University of Tasmania, TAS 7250, Australia; Department of Psychiatry, North-West Private Hospital, Burnie TAS 7320, Australia
| | - David M Benedek
- Centre for the Study of Traumatic Stress, Department of Psychiatry, Uniformed Services University School of Medicine, Bethesda, MD 20814, USA
| | - Robert J Ursano
- Centre for the Study of Traumatic Stress, Department of Psychiatry, Uniformed Services University School of Medicine, Bethesda, MD 20814, USA
| | - Juan J Canales
- Schools of Psychological Sciences, College of Health and Medicine, University of Tasmania, TAS 7250, Australia
| | - Luke R Johnson
- Schools of Psychological Sciences, College of Health and Medicine, University of Tasmania, TAS 7250, Australia; Centre for the Study of Traumatic Stress, Department of Psychiatry, Uniformed Services University School of Medicine, Bethesda, MD 20814, USA.
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Mugnaini M, Alfei JM, Bueno AM, Ferrer Monti RI, Urcelay GP. Fear memory modulation by incentive down and up-shifts. Behav Brain Res 2022; 422:113766. [DOI: 10.1016/j.bbr.2022.113766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 12/20/2021] [Accepted: 01/17/2022] [Indexed: 11/02/2022]
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Anxiety and cognitive-related effects of Δ 9-tetrahydrocannabinol (THC) are differentially mediated through distinct GSK-3 vs. Akt-mTOR pathways in the nucleus accumbens of male rats. Psychopharmacology (Berl) 2022; 239:509-524. [PMID: 34860284 DOI: 10.1007/s00213-021-06029-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 11/09/2021] [Indexed: 10/19/2022]
Abstract
RATIONALE Δ9-tetrahydrocannabinol (THC) is the primary psychoactive compound in cannabis and is responsible for cannabis-related neuropsychiatric side effects, including abnormal affective processing, cognitive and sensory filtering deficits and memory impairments. A critical neural region linked to the psychotropic effects of THC is the nucleus accumbens shell (NASh), an integrative mesocorticolimbic structure that sends and receives inputs from multiple brain areas known to be dysregulated in various disorders, including schizophrenia and anxiety-related disorders. Considerable evidence demonstrates functional differences between posterior vs. anterior NASh sub-regions in the processing of affective and cognitive behaviours influenced by THC. Nevertheless, the neuroanatomical regions and local molecular pathways responsible for these psychotropic effects are not currently understood. OBJECTIVES The objectives of this study were to characterize the effects of intra-accumbens THC in the anterior vs. posterior regions of the NASh during emotional memory formation, sensorimotor gating and anxiety-related behaviours. METHODS We performed an integrative series of translational behavioural pharmacological studies examining anxiety, sensorimotor gating and fear-related associative memory formation combined with regionally specific molecular signalling analyses in male Sprague Dawley rats. RESULTS We report that THC in the posterior NASh causes distortions in emotional salience attribution, impaired sensory filtering and memory retention and heightened anxiety, through a glycogen-synthase-kinase-3 (GSK-3)-β-catenin dependent signalling pathway. In contrast, THC in the anterior NASh produces anxiolytic effects via modulation of protein kinase B (Akt) phosphorylation states. CONCLUSIONS These findings reveal critical new insights into the neuroanatomical and molecular mechanisms associated with the differential neuropsychiatric side effects of THC in dissociable nucleus accumbens sub-regions.
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Shrestha P, Klann E. Spatiotemporally resolved protein synthesis as a molecular framework for memory consolidation. Trends Neurosci 2022; 45:297-311. [PMID: 35184897 PMCID: PMC8930706 DOI: 10.1016/j.tins.2022.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 01/21/2022] [Accepted: 01/25/2022] [Indexed: 01/25/2023]
Abstract
De novo protein synthesis is required for long-term memory consolidation. Dynamic regulation of protein synthesis occurs via a complex interplay of translation factors and modulators. Many components of the protein synthesis machinery have been targeted either pharmacologically or genetically to establish its requirement for memory. The combination of ligand/light-gating and genetic strategies, that is, chemogenetics and optogenetics, has begun to reveal the spatiotemporal resolution of protein synthesis in specific cell types during memory consolidation. This review summarizes current knowledge of the macroscopic and microscopic neural substrates for protein synthesis in memory consolidation. In addition, we highlight future directions for determining the localization and timing of de novo protein synthesis for memory consolidation with tools that permit unprecedented spatiotemporal precision.
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Affiliation(s)
- Prerana Shrestha
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY 11794, USA.
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY 10012, USA; NYU Neuroscience Institute, New York University Langone Medical Center, New York, NY 10016, USA.
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9
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Noyes NC, Phan A, Davis RL. Memory suppressor genes: Modulating acquisition, consolidation, and forgetting. Neuron 2021; 109:3211-3227. [PMID: 34450024 PMCID: PMC8542634 DOI: 10.1016/j.neuron.2021.08.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/15/2021] [Accepted: 07/30/2021] [Indexed: 02/06/2023]
Abstract
The brain has a remarkable but underappreciated capacity to limit memory formation and expression. The term "memory suppressor gene" was coined in 1998 as an attempt to explain emerging reports that some genes appeared to limit memory. At that time, only a handful of memory suppressor genes were known, and they were understood to work by limiting cAMP-dependent consolidation. In the intervening decades, almost 100 memory suppressor genes with diverse functions have been discovered that affect not only consolidation but also acquisition and forgetting. Here we highlight the surprising extent to which biological limits are placed on memory formation through reviewing the literature on memory suppressor genes. In this review, we present memory suppressors within the framework of their actions on different memory operations: acquisition, consolidation, and forgetting. This is followed by a discussion of the reasons why there may be a biological need to limit memory formation.
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Affiliation(s)
- Nathaniel C Noyes
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, FL 33458, USA
| | - Anna Phan
- Department of Biological Sciences, University of Alberta, 11355 Saskatchewan Drive, Edmonton, AB T6G 2E9, Canada
| | - Ronald L Davis
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, FL 33458, USA.
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Creatine Supplementation Upregulates mTORC1 Signaling and Markers of Synaptic Plasticity in the Dentate Gyrus While Ameliorating LPS-Induced Cognitive Impairment in Female Rats. Nutrients 2021; 13:nu13082758. [PMID: 34444918 PMCID: PMC8398736 DOI: 10.3390/nu13082758] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/06/2021] [Accepted: 08/10/2021] [Indexed: 11/27/2022] Open
Abstract
Mild cognitive impairment (MCI) designates the boundary area between cognitive function in natural aging and dementia, and this is viewed as a therapeutic window to prevent the occurrence of dementia. The current study investigated the neurocognitive effects of oral creatine (Cr) supplementation in young female Wistar rats that received intracerebroventricular injections of lipopolysaccharide (LPS) to mimic MCI. Neuromolecular changes within the dentate gyrus were analyzed following behavioral testing. We also investigated both neurocognitive and neuromolecular changes following Cr supplementation in the absence of LPS in young female Wistar rats to further investigate mechanisms. Interestingly, based on trial 2 of Barnes maze test, Cr supplementation ameliorated spatial learning and memory deficit induced by LPS, shown by decreased latency time and errors to reach the escape box (p < 0.0001, n = 12). Cr supplementation also attenuated recognition memory deficit induced by LPS, shown by increased amount of time taken to explore the new object (p = 0.002, n = 12) during novel object recognition testing. Within the dentate gyrus, Cr supplementation in LPS injected rats upregulated mTORC1 signaling (p = 0.026 for mTOR phosphorylation, p = 0.002 for p70S6K phosphorylation, n = 8) as well as the synapsin (p = 0.008) and PSD-95 synaptic proteins (p = 0.015), in comparisons to LPS injected rats. However, Cr supplementation failed to further enhance spatial memory and recognition memory in the absence of LPS. In conclusion, Cr ameliorates LPS-induced cognitive impairment in a rodent MCI model. Mechanistically, these phenotypic effects may, in part, be mitigated via an upregulation of mTORC1 signaling, and an enhancement in synaptogenesis in the dentate gyrus. While preliminary, these findings may inform future research investigating neurocognitive effects of Cr for MCI patients.
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de Souza LO, Machado GDB, de Freitas BS, Rodrigues SLC, Severo MPA, Molz P, da Silva JAC, Bromberg E, Roesler R, Schröder N. The G protein-coupled estrogen receptor (GPER) regulates recognition and aversively-motivated memory in male rats. Neurobiol Learn Mem 2021; 184:107499. [PMID: 34352396 DOI: 10.1016/j.nlm.2021.107499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 07/02/2021] [Accepted: 07/29/2021] [Indexed: 10/20/2022]
Abstract
Estrogens, particularly 17β-estradiol (estradiol, E2), regulate memory formation. E2 acts through its intracellular receptors, estrogen receptors (ER) ERα and ERβ, as well as a recently identified G protein-coupled estrogen receptor (GPER). Although the effects of E2 on memory have been investigated, studies examining the effects of GPER stimulation are scarce. Selective GPER agonism improves memory in ovariectomized female rats, but little information is available regarding the effects of GPER stimulation in male rodents. The aim of the present study was to investigate the effects of the GPER agonist, G1, on consolidation and reconsolidation of inhibitory avoidance (IA) and object recognition (OR) memory in male rats. Animals received vehicle, G1 (15, 75, 150 µg/kg; i.p.), or the GPER antagonist G15 (100 µg/kg; i.p.) immediately after training, or G1 (150 µg/kg; i.p.) 3 or 6 h after training. To investigate reconsolidation, G1 was administered immediately after IA retention Test 1. Results indicated that G1 administered immediately after training at the highest dose enhanced both OR and IA memory consolidation, while GPER blockade immediately after training impaired OR. No effects of GPER stimulation were observed when G1 was given 3 or 6 h after training or after Test 1. The present findings provide evidence that GPER is involved in the early stages of memory consolidation in both neutral and emotional memory tasks in male adult rats.
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Affiliation(s)
- Lariza Oliveira de Souza
- Department of Physiology, Institute for Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Gustavo Dalto Barroso Machado
- Department of Physiology, Institute for Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Betânia Souza de Freitas
- Neurobiology and Developmental Biology Laboratory, School of Health and Life Sciences, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Sarah Luize Camargo Rodrigues
- Department of Physiology, Institute for Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Maria Paula Arakaki Severo
- Department of Physiology, Institute for Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Patrícia Molz
- Department of Physiology, Institute for Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - José Afonso Corrêa da Silva
- Department of Physiology, Institute for Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Elke Bromberg
- Neurobiology and Developmental Biology Laboratory, School of Health and Life Sciences, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil; National Institute of Science and Technology for Translational Medicine (INCT-TM), Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Brasília, Brazil
| | - Rafael Roesler
- Department of Pharmacology, Institute for Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil; Cancer and Neurobiology Laboratory, Experimental Research Center, Clinical Hospital (CPE-HCPA), Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Nadja Schröder
- Department of Physiology, Institute for Basic Health Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil; National Institute of Science and Technology for Translational Medicine (INCT-TM), Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Brasília, Brazil.
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Reconsolidation of a post-ingestive nutrient memory requires mTOR in the central amygdala. Mol Psychiatry 2021; 26:2820-2836. [PMID: 32873898 DOI: 10.1038/s41380-020-00874-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 08/04/2020] [Accepted: 08/21/2020] [Indexed: 01/22/2023]
Abstract
The central control of feeding behavior and metabolic homeostasis has been proposed to involve a form of post-ingestive nutrient learning independent of the gustatory value of food. However, after such learning, it is unknown which brain regions or circuits are activated to retrieve the stored memory and whether this memory undergoes reconsolidation that depends on protein synthesis after its reactivation through retrieval. In the present study, using a conditioned-flavor-preference paradigm by associating flavors with intra-gastric infusion of glucose to minimize the evaluation of the taste of food, we show that retrieval of the post-ingestive nutrient-conditioned flavor memory stimulates multiple brain regions in mice, including the central nucleus of the amygdala (CeA). Moreover, memory retrieval activated the mammalian target of rapamycin complex 1 (mTORC1) in the CeA, while site-specific or systemic inhibition of mTORC1 immediately after retrieval prevented the subsequent expression of the post-ingestive nutrient-associated flavor memory, leading to a long-lasting suppression of reinstatement. Taken together, our findings suggest that the reconsolidation process of a post-ingestive nutrient memory modulates food preferences.
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13
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Bernabo M, Haubrich J, Gamache K, Nader K. Memory Destabilization and Reconsolidation Dynamically Regulate the PKMζ Maintenance Mechanism. J Neurosci 2021; 41:4880-4888. [PMID: 33888608 PMCID: PMC8260165 DOI: 10.1523/jneurosci.2093-20.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 03/30/2021] [Accepted: 04/02/2021] [Indexed: 11/21/2022] Open
Abstract
Useful memory must balance between stability and malleability. This puts effective memory storage at odds with plasticity processes, such as reconsolidation. What becomes of memory maintenance processes during synaptic plasticity is unknown. Here we examined the fate of the memory maintenance protein PKMζ during memory destabilization and reconsolidation in male rats. We found that NMDAR activation and proteasome activity induced a transient reduction in PKMζ protein following retrieval. During reconsolidation, new PKMζ was synthesized to re-store the memory. Failure to synthesize new PKMζ during reconsolidation impaired memory but uninterrupted PKMζ translation was not necessary for maintenance itself. Finally, NMDAR activation was necessary to render memories vulnerable to the amnesic effect of PKMζ-antisense. These findings outline a transient disruption and renewal of the PKMζ memory maintenance mechanism during plasticity. We argue that dynamic changes in PKMζ protein levels can serve as an exemplary model of the molecular changes underlying memory destabilization and reconsolidation.SIGNIFICANCE STATEMENT Maintenance of long-term memory relies on the persistent activity of PKMζ. However, after retrieval, memories can become transiently destabilized and must be reconsolidated within a few hours to persist. During this period of plasticity, what happens to maintenance processes, such as those involving PKMζ, is unknown. Here we describe dynamic changes to PKMζ expression during both destabilization and reconsolidation of auditory fear memory in the amygdala. We show that destabilization induces a NMDAR- and proteasome-dependent loss of synaptic PKMζ and that reconsolidation requires synthesis of new PKMζ. This work provides clear evidence that memory destabilization disrupts ongoing synaptic maintenance processes which are restored during reconsolidation.
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Affiliation(s)
- Matteo Bernabo
- Integrated Program in Neuroscience, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Josue Haubrich
- Department of Psychology, McGill University, Montreal, Quebec H3A 1B1, Canada
| | - Karine Gamache
- Department of Psychology, McGill University, Montreal, Quebec H3A 1B1, Canada
| | - Karim Nader
- Department of Psychology, McGill University, Montreal, Quebec H3A 1B1, Canada
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14
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Schroeder S, Hofer SJ, Zimmermann A, Pechlaner R, Dammbrueck C, Pendl T, Marcello GM, Pogatschnigg V, Bergmann M, Müller M, Gschiel V, Ristic S, Tadic J, Iwata K, Richter G, Farzi A, Üçal M, Schäfer U, Poglitsch M, Royer P, Mekis R, Agreiter M, Tölle RC, Sótonyi P, Willeit J, Mairhofer B, Niederkofler H, Pallhuber I, Rungger G, Tilg H, Defrancesco M, Marksteiner J, Sinner F, Magnes C, Pieber TR, Holzer P, Kroemer G, Carmona-Gutierrez D, Scorrano L, Dengjel J, Madl T, Sedej S, Sigrist SJ, Rácz B, Kiechl S, Eisenberg T, Madeo F. Dietary spermidine improves cognitive function. Cell Rep 2021; 35:108985. [PMID: 33852843 DOI: 10.1016/j.celrep.2021.108985] [Citation(s) in RCA: 91] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 02/08/2021] [Accepted: 03/22/2021] [Indexed: 12/22/2022] Open
Abstract
Decreased cognitive performance is a hallmark of brain aging, but the underlying mechanisms and potential therapeutic avenues remain poorly understood. Recent studies have revealed health-protective and lifespan-extending effects of dietary spermidine, a natural autophagy-promoting polyamine. Here, we show that dietary spermidine passes the blood-brain barrier in mice and increases hippocampal eIF5A hypusination and mitochondrial function. Spermidine feeding in aged mice affects behavior in homecage environment tasks, improves spatial learning, and increases hippocampal respiratory competence. In a Drosophila aging model, spermidine boosts mitochondrial respiratory capacity, an effect that requires the autophagy regulator Atg7 and the mitophagy mediators Parkin and Pink1. Neuron-specific Pink1 knockdown abolishes spermidine-induced improvement of olfactory associative learning. This suggests that the maintenance of mitochondrial and autophagic function is essential for enhanced cognition by spermidine feeding. Finally, we show large-scale prospective data linking higher dietary spermidine intake with a reduced risk for cognitive impairment in humans.
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Affiliation(s)
- Sabrina Schroeder
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria
| | - Sebastian J Hofer
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria; Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Andreas Zimmermann
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria; Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Raimund Pechlaner
- Department of Neurology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | | | - Tobias Pendl
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - G Mark Marcello
- Department of Anatomy and Histology, University of Veterinary Medicine Budapest, 1078 Budapest, Hungary
| | - Viktoria Pogatschnigg
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - Martina Bergmann
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - Melanie Müller
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - Verena Gschiel
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - Selena Ristic
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - Jelena Tadic
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria; Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Keiko Iwata
- Veneto Institute of Molecular Medicine, 35129 Padova, Italy; Research Center for Child Mental Development, University of Fukui, 910-1193 Fukui, Japan; Department of Biology, University of Padova, 35121 Padova, Italy
| | - Gesa Richter
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging Molecular Biology and Biochemistry Medical University of Graz, 8010 Graz, Austria
| | - Aitak Farzi
- Otto Loewi Research Center (for Vascular Biology, Immunology and Inflammation), Division of Pharmacology, Medical University of Graz (MUG), 8010 Graz, Austria
| | - Muammer Üçal
- Department of Neurosurgery, RU Experimental Neurotraumatology, Medical University Graz, 8036 Graz, Austria
| | - Ute Schäfer
- Department of Neurosurgery, RU Experimental Neurotraumatology, Medical University Graz, 8036 Graz, Austria
| | - Michael Poglitsch
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - Philipp Royer
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - Ronald Mekis
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - Marlene Agreiter
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - Regine C Tölle
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
| | - Péter Sótonyi
- Department of Anatomy and Histology, University of Veterinary Medicine Budapest, 1078 Budapest, Hungary
| | - Johann Willeit
- Department of Neurology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | | | | | | | | | - Herbert Tilg
- Department of Internal Medicine I, Gastroenterology, Hepatology, Endocrinology and Metabolism, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Michaela Defrancesco
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Josef Marksteiner
- Department of Psychiatry and Psychotherapy A, Hall State Hospital, 6060 Hall in Tirol, Austria
| | - Frank Sinner
- HEALTH-Institute for Biomedicine and Health Sciences, Joanneum Research Forschungsgesellschaft mbH, 8010 Graz, Austria; Division of Endocrinology and Diabetology, Department of Internal Medicine, Medical University of Graz, 8036 Graz, Austria
| | - Christoph Magnes
- HEALTH-Institute for Biomedicine and Health Sciences, Joanneum Research Forschungsgesellschaft mbH, 8010 Graz, Austria
| | - Thomas R Pieber
- BioTechMed-Graz, 8010 Graz, Austria; HEALTH-Institute for Biomedicine and Health Sciences, Joanneum Research Forschungsgesellschaft mbH, 8010 Graz, Austria; Division of Endocrinology and Diabetology, Department of Internal Medicine, Medical University of Graz, 8036 Graz, Austria
| | - Peter Holzer
- Otto Loewi Research Center (for Vascular Biology, Immunology and Inflammation), Division of Pharmacology, Medical University of Graz (MUG), 8010 Graz, Austria
| | - Guido Kroemer
- Equipe Labellisée par la Ligue Contre le Cancer, Université Paris Descartes, Université Paris Diderot, Université Sorbonne Paris Cité, INSERM U1138, Centre de Recherche des Cordeliers, 75006 Paris, France; Metabolomics and Cell Biology Platforms, Institut Gustave Roussy, 94 805 Villejuif, France; Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, 75015 Paris, France; Suzhou Institute for Systems Biology, Chinese Academy of Sciences, 215123 Suzhou, China; Department of Women's and Children's Health, Karolinska University Hospital, 171 77 Stockholm, Sweden
| | | | - Luca Scorrano
- Veneto Institute of Molecular Medicine, 35129 Padova, Italy; Department of Biology, University of Padova, 35121 Padova, Italy
| | - Jörn Dengjel
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland
| | - Tobias Madl
- BioTechMed-Graz, 8010 Graz, Austria; Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging Molecular Biology and Biochemistry Medical University of Graz, 8010 Graz, Austria
| | - Simon Sedej
- BioTechMed-Graz, 8010 Graz, Austria; Department of Cardiology, Medical University of Graz, 8036 Graz, Austria; Faculty of Medicine, University of Maribor, 2000 Maribor, Slovenia
| | - Stephan J Sigrist
- Institute of Biology/Genetics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Bence Rácz
- Department of Anatomy and Histology, University of Veterinary Medicine Budapest, 1078 Budapest, Hungary
| | - Stefan Kiechl
- Department of Neurology, Medical University of Innsbruck, 6020 Innsbruck, Austria; VASCage, Research Centre on Vascular Ageing and Stroke, 6020 Innsbruck, Austria.
| | - Tobias Eisenberg
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria; Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria.
| | - Frank Madeo
- Institute of Molecular Biosciences, NAWI Graz, University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria; Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria.
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López‐Gambero AJ, Rodríguez de Fonseca F, Suárez J. Energy sensors in drug addiction: A potential therapeutic target. Addict Biol 2021; 26:e12936. [PMID: 32638485 DOI: 10.1111/adb.12936] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 06/10/2020] [Accepted: 06/15/2020] [Indexed: 01/05/2023]
Abstract
Addiction is defined as the repeated exposure and compulsive seek of psychotropic drugs that, despite the harmful effects, generate relapse after the abstinence period. The psychophysiological processes associated with drug addiction (acquisition/expression, withdrawal, and relapse) imply important alterations in neurotransmission and changes in presynaptic and postsynaptic plasticity and cellular structure (neuroadaptations) in neurons of the reward circuits (dopaminergic neuronal activity) and other corticolimbic regions. These neuroadaptation mechanisms imply important changes in neuronal energy balance and protein synthesis machinery. Scientific literature links drug-induced stimulation of dopaminergic and glutamatergic pathways along with presence of neurotrophic factors with alterations in synaptic plasticity and membrane excitability driven by metabolic sensors. Here, we provide current knowledge of the role of molecular targets that constitute true metabolic/energy sensors such as AMPK, mTOR, ERK, or KATP in the development of the different phases of addiction standing out the main brain regions (ventral tegmental area, nucleus accumbens, hippocampus, and amygdala) constituting the hubs in the development of addiction. Because the available treatments show very limited effectiveness, evaluating the drug efficacy of AMPK and mTOR specific modulators opens up the possibility of testing novel pharmacotherapies for an individualized approach in drug abuse.
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Affiliation(s)
- Antonio Jesús López‐Gambero
- Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario de Málaga Universidad de Málaga Málaga Spain
| | - Fernando Rodríguez de Fonseca
- Instituto de Investigación Biomédica de Málaga (IBIMA), UGC Salud Mental Hospital Regional Universitario de Málaga Málaga Spain
| | - Juan Suárez
- Instituto de Investigación Biomédica de Málaga (IBIMA), UGC Salud Mental Hospital Regional Universitario de Málaga Málaga Spain
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16
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Troyner F, Bertoglio LJ. Nucleus reuniens of the thalamus controls fear memory reconsolidation. Neurobiol Learn Mem 2020; 177:107343. [PMID: 33242589 DOI: 10.1016/j.nlm.2020.107343] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/08/2020] [Accepted: 11/16/2020] [Indexed: 01/09/2023]
Abstract
The nucleus reuniens has been shown to support the acquisition, consolidation, maintenance, destabilization upon retrieval, and extinction of aversive memories. However, the direct participation of this thalamic subregion in memory reconsolidation is yet to be examined. The present study addressed this question in contextually fear-conditioned rats. Post-reactivation infusion of the GABAA receptor agonist muscimol, the glutamate N2A-containing NMDA receptor antagonist TCN-201, or the protein synthesis inhibitor anisomycin into the NR induced significant impairments in memory reconsolidation. Administering muscimol or TCN-201 and anisomycin locally, or associating locally infused muscimol or TCN-201 with systemically administered clonidine, an α2-receptor adrenergic agonist that attenuates the noradrenergic tonus associated with memory reconsolidation, produced no further reduction in freezing times when compared with the muscimol-vehicle, TCN-201-vehicle, vehicle-anisomycin, and vehicle-clonidine groups. This pattern of results indicates that such treatment combinations produced no additive/synergistic effects on reconsolidation. It is plausible that NR inactivation and antagonism of glutamate N2A-containing NMDA receptors weakened/prevented the subsequent action of anisomycin and clonidine because they disrupted the early stages of signal transduction pathways involved in memory reconsolidation. It is noteworthy that these pharmacological interventions, either alone or combined, induced no contextual memory specificity changes, as assessed in a later test in a novel and unpaired context. Besides, omitting memory reactivation precluded the impairing effects of muscimol, TCN-201, anisomycin, and clonidine on reconsolidation. Together, the present findings demonstrate interacting mechanisms through which the NR can regulate contextual fear memory restabilization.
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Affiliation(s)
- Fernanda Troyner
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil
| | - Leandro Jose Bertoglio
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianopolis, SC, Brazil.
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17
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Liu Y, Jin S, Yang YT, Bai Y, Yong H, Bao W. Cognitive dysfunction associated with activation of the mTOR signaling pathway after TSH suppression therapy in rats. Endocr J 2020; 67:1063-1070. [PMID: 32581146 DOI: 10.1507/endocrj.ej20-0134] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Thyroid stimulating hormone (TSH) suppression therapy after thyroid carcinoma surgery could lead to cognitive impairment. But, the possible mechanism of TSH suppression therapy impairs cognitive function is yet unknown. In this study, forty Wistar rats were randomized into the sham operation control (OC), total thyroidectomy (TD), thyroxine replacement therapy (TR), and TSH suppression therapy (TS) groups. We observed that compared to the OC group, escape latency on 1-4 days was significantly prolonged in the TD and TS groups, and the number of rats crossing the virtual platform was significantly reduced in the TD and TS groups. In the TD, TR, and TS groups, the residence time in the target quadrant was significantly decreased, while the activity distance in the target quadrant in the TD group was significantly decreased compared with OC group. In the TD and TS groups, the pyramidal cells in the hippocampal CA1 region showed a disordered arrangement. The cytoplasm was lightly stained, the cells were swollen and round, and spotty liquefaction necrosis could be observed. Compared to the OC group, hippocampal p-mTOR and p-p70s6k levels were significantly decreased in the TD group, while no significant changes were detected in the TR group. Hippocampal p-mTOR and p-p70s6k amounts in the TS group were significantly increased compared with OC group. These results indicated that TSH suppression therapy after total thyroidectomy in rats could impair cognitive function, which might be related to the activation of the mTOR signaling pathway and the damage and necrosis of hippocampal neurons.
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Affiliation(s)
- Yousheng Liu
- Department of General Surgery, Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010050, Inner Mongolia Autonomous Region, China
| | - Shan Jin
- Department of General Surgery, Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010050, Inner Mongolia Autonomous Region, China
| | - Yun-Tian Yang
- Department of Neurology, Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010050, Inner Mongolia Autonomous Region, China
| | - Yinbao Bai
- Department of General Surgery, Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010050, Inner Mongolia Autonomous Region, China
| | - Hong Yong
- Department of General Surgery, Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010050, Inner Mongolia Autonomous Region, China
| | - Wuyuntu Bao
- Department of General Surgery, Affiliated Hospital of Inner Mongolia Medical University, Hohhot 010050, Inner Mongolia Autonomous Region, China
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18
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MacCallum PE, Blundell J. The mTORC1 inhibitor rapamycin and the mTORC1/2 inhibitor AZD2014 impair the consolidation and persistence of contextual fear memory. Psychopharmacology (Berl) 2020; 237:2795-2808. [PMID: 32601986 DOI: 10.1007/s00213-020-05573-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 05/29/2020] [Indexed: 12/17/2022]
Abstract
RATIONALE The mechanistic target of rapamycin (mTOR) kinase mediates various long-lasting forms of synaptic and behavioural plasticity. However, there is little information concerning the temporal pattern of mTOR activation and susceptibility to pharmacological intervention during consolidation of contextual fear memory. Moreover, the contribution of both mTOR complex 1 and 2 together or the mTOR complex 1 downstream effector p70S6K (S6K1) to consolidation of contextual fear memory is unknown. OBJECTIVE Here, we tested whether different timepoints of vulnerability to rapamycin, a first generation mTOR complex 1 inhibitor, exist for contextual fear memory consolidation and persistence. We also sought to characterize the effects of dually inhibiting mTORC1/2 as well as S6K1 on fear memory formation and persistence. METHODS Rapamycin was injected systemically to mice immediately, 3 h, or 12 h after contextual fear conditioning, and retention was measured at different timepoints thereafter. To determine the effects of a single injection of the dual mTROC1/2 inhibitor AZD2014 after learning on memory consolidation and persistence, a dose-response experiment was carried out. Memory formation and persistence was also assessed in response to the S6K1 inhibitor PF-4708671. RESULTS A single systemic injection of rapamycin immediately or 3 h, but not 12 h, after learning impaired the formation and persistence of contextual fear memory. AZD2014 was found, with limitations, to dose-dependently attenuate memory consolidation and persistence at the highest dose tested (50 mg/kg). In contrast, PF-4708671 had no effect on consolidation or persistence. CONCLUSION Our results indicate the need to further understand the role of mTORC1/2 kinase activity in the molecular mechanisms underlying memory processing and also demonstrate that the effects of mTORC1 inhibition at different timepoints well after learning on memory consolidation and persistence.
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Affiliation(s)
- Phillip E MacCallum
- Department of Psychology, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Jacqueline Blundell
- Department of Psychology, Memorial University of Newfoundland, St. John's, NL, Canada.
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19
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Norwitz NG, Querfurth H. mTOR Mysteries: Nuances and Questions About the Mechanistic Target of Rapamycin in Neurodegeneration. Front Neurosci 2020; 14:775. [PMID: 32903821 PMCID: PMC7438931 DOI: 10.3389/fnins.2020.00775] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 07/01/2020] [Indexed: 01/25/2023] Open
Abstract
The mechanistic target of rapamycin protein complex, mTORC1, has received attention in recent years for its role in aging and neurodegenerative diseases, such as Alzheimer's disease. Numerous excellent reviews have been written on the pathways and drug targeting of this keystone regulator of metabolism. However, none have specifically highlighted several important nuances of mTOR regulation as relates to neurodegeneration. Herein, we focus on six such nuances/open questions: (1) "Antagonistic pleiotropy" - Should we weigh the beneficial anabolic functions of mTORC1 against its harmful inhibition of autophagy? (2) "Early/late-stage specificity" - Does the relative importance of these neuroprotective/neurotoxic actions change as a disease progresses? (3) "Regional specificity" - Does mTOR signaling respond differently to the same interventions in different brain regions? (4) "Disease specificity" - Could the same intervention to inhibit mTORC1 help in one disease and cause harm in another disease? (5) "Personalized therapy" - Might genetically-informed personalized therapies that inhibit particular nodes in the mTORC1 regulatory network be more effective than generalized therapies? (6) "Lifestyle interventions" - Could specific diets, micronutrients, or exercise alter mTORC1 signaling to prevent or improve the progression neurodegenerative diseases? This manuscript is devoted to discussing recent research findings that offer insights into these gaps in the literature, with the aim of inspiring further inquiry.
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Affiliation(s)
- Nicholas G. Norwitz
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Henry Querfurth
- Department of Neurology, Tufts Medical Center, Boston, MA, United States
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20
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Abdo Qaid EY, Zulkipli NN, Zakaria R, Ahmad AH, Othman Z, Muthuraju S, Sasongko TH. The role of mTOR signalling pathway in hypoxia-induced cognitive impairment. Int J Neurosci 2020; 131:482-488. [PMID: 32202188 DOI: 10.1080/00207454.2020.1746308] [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] [Indexed: 02/06/2023]
Abstract
Hypoxia has been associated with cognitive impairment. Many studies have investigated the role of mTOR signalling pathway in cognitive functions but its role in hypoxia-induced cognitive impairment remains controversial. This review aimed to elucidate the role of mTOR in the mechanisms of cognitive impairment that may pave the way towards the mechanistic understanding and therapeutic intervention of hypoxia-induced cognitive impairment. mTORC1 is normally regulated during mild or acute hypoxic exposure giving rise to neuroprotection, whereas it is overactivated during severe or chronic hypoxia giving rise to neuronal cells death. Thus, it is worth exploring the possibility of maintaining normal mTORC1 activity and thereby preventing cognitive impairment during severe or chronic hypoxia.
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Affiliation(s)
| | - Ninie Nadia Zulkipli
- School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, 16150, Malaysia
| | - Rahimah Zakaria
- School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, 16150, Malaysia
| | - Asma Hayati Ahmad
- School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, 16150, Malaysia
| | - Zahiruddin Othman
- School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, 16150, Malaysia
| | - Sangu Muthuraju
- School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, 16150, Malaysia
| | - Teguh Haryo Sasongko
- Perdana University-RCSI School of Medicine, Perdana University Center for Research Excellence, Jalan MAEPS Perdana, Serdang, Selangor, 43400, Malaysia
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21
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Moon GJ, Shin M, Kim SR. Upregulation of Neuronal Rheb(S16H) for Hippocampal Protection in the Adult Brain. Int J Mol Sci 2020; 21:E2023. [PMID: 32188096 PMCID: PMC7139780 DOI: 10.3390/ijms21062023] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 03/14/2020] [Accepted: 03/16/2020] [Indexed: 12/20/2022] Open
Abstract
Ras homolog protein enriched in brain (Rheb) is a key activator of mammalian target of rapamycin complex 1 (mTORC1). The activation of mTORC1 by Rheb is associated with various processes such as protein synthesis, neuronal growth, differentiation, axonal regeneration, energy homeostasis, autophagy, and amino acid uptake. In addition, Rheb-mTORC1 signaling plays a crucial role in preventing the neurodegeneration of hippocampal neurons in the adult brain. Increasing evidence suggests that the constitutive activation of Rheb has beneficial effects against neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Our recent studies revealed that adeno-associated virus serotype 1 (AAV1) transduction with Rheb(S16H), a constitutively active form of Rheb, exhibits neuroprotective properties through the induction of various neurotrophic factors, promoting neurotrophic interactions between neurons and astrocytes in the hippocampus of the adult brain. This review provides compelling evidence for the therapeutic potential of AAV1-Rheb(S16H) transduction in the hippocampus of the adult brain by exploring its neuroprotective effects and mechanisms.
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Affiliation(s)
- Gyeong Joon Moon
- BK21 plus KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu 41566, Korea;
| | - Minsang Shin
- Brain Science and Engineering Institute, Kyungpook National University, Daegu 41566, Korea;
- Department of Microbiology, School of Medicine, Kyungpook National University, Daegu 41944, Korea
| | - Sang Ryong Kim
- BK21 plus KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu 41566, Korea;
- Brain Science and Engineering Institute, Kyungpook National University, Daegu 41566, Korea;
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22
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Meng S, Xia W, Pan M, Jia Y, He Z, Ge W. Proteomics profiling and pathway analysis of hippocampal aging in rhesus monkeys. BMC Neurosci 2020; 21:2. [PMID: 31941443 PMCID: PMC6964096 DOI: 10.1186/s12868-020-0550-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 01/07/2020] [Indexed: 02/07/2023] Open
Abstract
Background Aged rhesus monkeys exhibit deficits in memory mediated by the hippocampus. Although extensive research has been carried out on the characteristics of human hippocampal aging, there is still very little scientific understanding of the changes associated with hippocampal aging in rhesus monkeys. To explore the proteomics profiling and pathway-related changes in the rhesus hippocampus during the aging process, we conducted a high throughput quantitative proteomics analysis of hippocampal samples from two groups of rhesus macaques aged 6 years and 20 years, using 2-plex tandem mass tag (TMT) labeling. In addition, we used a comprehensive bioinformatics analysis approach to investigate the enriched signaling pathways of differentially expressed proteins (the ratios of 20-years vs. 6-years, ≥ 1.20 or ≤ 0.83). Results In total, 3260 proteins were identified with a high level of confidence in rhesus hippocampus. We found 367 differentially expressed proteins related to rhesus hippocampus aging. Based on biological pathway analysis, we found these aging-related proteins were predominantly enriched in the electron transport chain, NRF2 pathway, focal adhesion–PI3K–AKT–mTOR signaling pathway and cytoplasmic ribosome proteins. Data are available via ProteomeXchange with identifier PXD011398. Conclusion This study provides a detail description of the proteomics profile related to rhesus hippocampal aging. These findings should make an important contribution to further mechanistic studies, marker selection and drug development for the prevention and treatment of aging or age-related neurodegeneration.
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Affiliation(s)
- Shu Meng
- State Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Dongdan Santiao 5# Dongcheng District, Beijing, 100005, China
| | - Wenchao Xia
- State Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Dongdan Santiao 5# Dongcheng District, Beijing, 100005, China
| | - Meng Pan
- State Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Dongdan Santiao 5# Dongcheng District, Beijing, 100005, China
| | - Yangjie Jia
- State Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Dongdan Santiao 5# Dongcheng District, Beijing, 100005, China
| | - Zhanlong He
- Yunnan Key Laboratory of Vaccine Research and Development on Severe Infectious Disease, Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, 650118, Yunnan, China.
| | - Wei Ge
- State Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Dongdan Santiao 5# Dongcheng District, Beijing, 100005, China. .,Department of Neurosurgery, Affiliated Hospital of Hebei University, Baoding, 071000, China.
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Kamboj K, Jana S, Sharma SK. Mechanisms of protein kinase C-induced sustained activation of extracellular signal-regulated kinase in the hippocampus. Biochem Biophys Res Commun 2019; 520:453-458. [PMID: 31607483 DOI: 10.1016/j.bbrc.2019.10.046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 10/03/2019] [Indexed: 10/25/2022]
Abstract
Protein Kinase C (PKC) and extracellular signal-regulated kinase (ERK) regulate synaptic plasticity and memory. PKC activation enhances long-term potentiation (LTP) in the hippocampal slices. In addition, activation of PKC by phorbol 12,13-diacetate (PDA) induces ERK activation. However, the mechanisms involved in PDA-induced activation of ERK are not well understood. Using hippocampal slices, we report that PDA induces a sustained activation of ERK. PDA-induced sustained ERK activation critically requires protein synthesis as well as transcription, the cellular processes that play crucial roles in long-lasting LTP and memory. In addition, the mammalian target of rapamycin activity is required for PDA-induced sustained ERK activation. Further, we show that growth factor signalling plays a critical role in PDA-induced sustained ERK activation. These results suggest that sustained ERK activation may have an important role in LTP.
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Affiliation(s)
- Kautuk Kamboj
- National Brain Research Centre, Manesar, 122052, Haryana, India
| | - Subhajit Jana
- National Brain Research Centre, Manesar, 122052, Haryana, India
| | - Shiv K Sharma
- National Brain Research Centre, Manesar, 122052, Haryana, India.
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24
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Ferrara NC, Jarome TJ, Cullen PK, Orsi SA, Kwapis JL, Trask S, Pullins SE, Helmstetter FJ. GluR2 endocytosis-dependent protein degradation in the amygdala mediates memory updating. Sci Rep 2019; 9:5180. [PMID: 30914678 PMCID: PMC6435726 DOI: 10.1038/s41598-019-41526-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 02/28/2019] [Indexed: 01/08/2023] Open
Abstract
Associations learned during Pavlovian fear conditioning are rapidly acquired and long lasting, providing an ideal model for studying long-term memory formation, storage, and retrieval. During retrieval, these memories can “destabilize” and become labile, allowing a transient “reconsolidation” window during which the memory can be updated, suggesting that reconsolidation could be an attractive target for the modification of memories related to past traumatic experiences. This memory destabilization process is regulated by protein degradation and GluR2-endocytosis in the amygdala. However, it is currently unknown if retrieval-dependent GluR2-endocytosis in the amygdala is critical for incorporation of new information into the memory trace. We examined whether the addition of new information during memory retrieval required GluR2-endocytosis to modify the original memory. The presentation of two foot shocks of weaker intensity during retrieval resulted in GluR2 endocytosis-dependent increase in fear responding on a later test, suggesting modification of the original memory. This increase in fear expression was associated with increased protein degradation and zif268 expression in the same population of cells in the amygdala, indicating increased destabilization processes and cellular activity, and both were lost following blockade of GluR2-endocytosis. These data suggest that the endocytosis of GluR2-containing AMPA receptors in the amygdala regulates retrieval-induced strengthening of memories for traumatic events by modulating cellular destabilization and activity.
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Affiliation(s)
- Nicole C Ferrara
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Timothy J Jarome
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA.,Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.,School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Patrick K Cullen
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Sabrina A Orsi
- Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.,School of Neuroscience, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Janine L Kwapis
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Sydney Trask
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Shane E Pullins
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Fred J Helmstetter
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, USA.
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25
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The Possible Role of Neurobeachin in Extinction of Contextual Fear Memory. Sci Rep 2018; 8:13752. [PMID: 30213954 PMCID: PMC6137154 DOI: 10.1038/s41598-018-30589-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 08/02/2018] [Indexed: 11/18/2022] Open
Abstract
Established fear memory becomes vulnerable to disruption after memory retrieval and extinction; this labile state is critical for inhibiting the return of fear memory. However, the labile state has a very narrow time window after retrieval, and underlying molecular mechanisms are not well known. To that end, we isolated the hippocampus immediately after fear memory retrieval and performed proteomics. We identified Neurobeachin (NBEA), an autism-related regulator of synaptic protein trafficking, to be upregulated after contextual fear memory retrieval. NBEA protein expression was rapid and transient after fear memory retrieval at the synapse. Nbea mRNA was enriched at the synapses, and the rapid induction of NBEA expression was blocked by inhibition of the mammalian target of rapamycin (mTOR)-dependent signaling pathway. Mice with cornu ammonis 1 (CA1)-specific Nbea shRNA knockdown showed normal fear acquisition and contextual fear memory but impaired extinction, suggesting an important role of Nbea in fear memory extinction processes. Consistently, Nbea heterozygotes showed normal fear acquisition and fear memory recall but showed impairment in extinction. Our data suggest that NBEA is necessary either for induction of memory lability or for the physiological process of memory extinction.
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26
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Pharmacological inhibition of 2-arachidonoilglycerol hydrolysis enhances memory consolidation in rats through CB2 receptor activation and mTOR signaling modulation. Neuropharmacology 2018; 138:210-218. [DOI: 10.1016/j.neuropharm.2018.05.030] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 04/09/2018] [Accepted: 05/24/2018] [Indexed: 11/24/2022]
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27
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EZH2 Methyltransferase Activity Controls Pten Expression and mTOR Signaling during Fear Memory Reconsolidation. J Neurosci 2018; 38:7635-7648. [PMID: 30030400 DOI: 10.1523/jneurosci.0538-18.2018] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 06/20/2018] [Accepted: 07/07/2018] [Indexed: 12/11/2022] Open
Abstract
Memory retrieval induces a transient period of increased transcriptional and translational regulation in neurons called reconsolidation, which is regulated by the protein kinase B (AKT)-mammalian target of rapamycin (mTOR) pathway. However, it is currently unknown how activation of the AKT-mTOR pathway is regulated during the reconsolidation process. Here, we found that in male rats retrieval of a contextual fear memory transiently increased Enhancer of Zeste Homolog 2 (EZH2) levels along with increased histone H3 lysine 27 trimethylation (H3K27me3) levels, which correlated with decreased levels of phosphatase and tensin homolog (PTEN), a potent inhibitor of AKT-mTOR-dependent signaling in the hippocampus. Further experiments found increased H3K27me3 levels and DNA methylation across the Pten promoter and coding regions, indicating transcriptional silencing of the Pten gene. Pten H3K27me3 levels did not change following training or after the retrieval of a remote (old) fear memory, suggesting that this mechanism of Pten repression was specific to the reconsolidation of a new memory. In vivo siRNA-mediated knockdown of Ezh2 in the hippocampus abolished retrieval-induced increases in H3K27me3 and prevented decreases in PTEN levels. Ezh2 knockdown attenuated increases in the phosphorylation of AKT and mTOR following retrieval, which could be restored by simultaneously reducing Pten, suggesting that H3K27me3 regulates AKT-mTOR phosphorylation via repression of Pten Consistent with these results, knockdown of Ezh2 in area CA1 before retrieval impaired memory on later tests. Collectively, these results suggest that EZH2-mediated H3K27me3 plays a critical role in the repression of Pten transcription necessary for AKT-mTOR activation and memory reconsolidation following retrieval.SIGNIFICANCE STATEMENT Understanding how critical translation pathways, like mTOR-mediated protein synthesis, are regulated during the memory storage process is necessary for improving memory impairments. This study tests whether mTOR activation is coupled to epigenetic mechanisms in the hippocampus following the retrieval of a contextual fear memory. Specifically, this study evaluates the role of epigenetic modifications in the form of histone methylation in downstream mTOR translational control during learning-dependent synaptic plasticity in neurons. Considering the broad implications of transcriptional and translational mechanisms in synaptic plasticity, psychiatric, and neurological and neurodegenerative disorders, these data are of interest to the neuroscience community due to the robust and specific regulation of mTOR signaling we found to be dependent on repressive histone methylation.
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28
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Regulation of filial imprinting and structural plasticity by mTORC1 in newborn chickens. Sci Rep 2018; 8:8044. [PMID: 29795185 PMCID: PMC5966437 DOI: 10.1038/s41598-018-26479-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 05/11/2018] [Indexed: 12/19/2022] Open
Abstract
Dysregulation of the mechanistic target of rapamycin complex 1 (mTORC1) signaling leads to memory deficits and abnormal social behaviors in adults. However, whether mTORC1 is involved in critical periods of early learning remains largely unexplored. Our study addressed this question by investigating imprinting, a form of learning constrained to a sensitive period that supports filial attachment, in newborn chickens. Imprinting to virtual objects and sounds was assessed after acute manipulations of mTORC1. To further understand the role of mTORC1 during the critical period, structural plasticity was analyzed using DiOlistic labeling of dendritic spines. We found that mTORC1 is required for the emergence of experience-dependent preferences and structural plasticity within brain regions controlling behavior. Furthermore, upon critical period closure, pharmacological activation of the AKT/mTORC1 pathway was sufficient to rescue imprinting across sensory modalities. Thus, our results uncover a novel role of mTORC1 in the formation of imprinted memories and experience-dependent reorganization of neural circuits during a critical period.
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29
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Abstract
The mechanistic target of rapamycin (mTOR) is an evolutionarily conserved serine/threonine kinase that senses and integrates environmental information into cellular regulation and homeostasis. Accumulating evidence has suggested a master role of mTOR signalling in many fundamental aspects of cell biology and organismal development. mTOR deregulation is implicated in a broad range of pathological conditions, including diabetes, cancer, neurodegenerative diseases, myopathies, inflammatory, infectious, and autoimmune conditions. Here, we review recent advances in our knowledge of mTOR signalling in mammalian physiology. We also discuss the impact of mTOR alteration in human diseases and how targeting mTOR function can treat human diseases.
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Affiliation(s)
- Yassine El Hiani
- a Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS B3H 4R2, Canada
| | - Emmanuel Eroume-A Egom
- b Jewish General Hospital and Lady Davis Institute for Medical Research, Montreal, QC H3T 1E2, Canada
| | - Xian-Ping Dong
- a Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS B3H 4R2, Canada
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30
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Jobim PFC, Dos Santos CEI, Jeromel L, Pellicon P, Amaral L, Dias JF. Changes in the element concentration of the dorsal hippocampus CA1 region during memory consolidation and reconsolidation. J Chem Neuroanat 2017; 90:49-56. [PMID: 29248756 DOI: 10.1016/j.jchemneu.2017.12.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/12/2017] [Accepted: 12/13/2017] [Indexed: 10/18/2022]
Abstract
The concentration and distribution of Mg, P, Cl, K, Cu and Zn in the dorsal hippocampus CA1 region of rat brains were studied during memory consolidation and reconsolidation processes stimulated with inhibitory avoidance (IA) tests. Experimental rats were divided into four groups: i) group not submitted to inhibitory avoidance task (IA-N); ii) group submitted to inhibitory avoidance training session (IA-Y); iii) group submitted to inhibitory avoidance reactivation session but did not step down from the platform (IAR-N); and iv) group submitted to avoidance reactivation session and stepped down from the platform (IAR-Y). Elemental concentration and distribution in the CA1 hippocampus region were obtained through the Particle-Induced X-ray Emission (PIXE) technique. The results indicate that the concentration of Mg, P, Cl, K and Cu increased during memory consolidation. During the memory reconsolidation process, the concentrations of Mg, P, Cl and K increased, while Cu and Zn had no significant changes with respect to their basal condition. These results show that the major part of these elements may be engaged in memory consolidation could be also participating in memory reconsolidation. For all elements, the general trend related to their concentration did not change during reconsolidation regardless the presence of a novelty event, i.e. stepping down from the platform.
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Affiliation(s)
- Paulo Fernandes Costa Jobim
- Physiology Department, Federal University of Health Sciences of Porto Alegre, Rua Sarmento Leite 245, CEP 90050-170, Porto Alegre, RS, Brazil.
| | - Carla Eliete Iochims Dos Santos
- Institute of Physics, Statistics and Mathematics, Federal University of Rio Grande, CEP 95500-000, Santo Antônio da Patrulha, RS, Brazil.
| | - Luka Jeromel
- Department for Low and Medium Energy Physics, Jožef Stefan Institute, SI-1000, Ljubljana, Slovenia.
| | - Primoz Pellicon
- Department for Low and Medium Energy Physics, Jožef Stefan Institute, SI-1000, Ljubljana, Slovenia.
| | - Livio Amaral
- Ion Implantation Laboratory, Institute of Physics, Federal University of Rio Grande do Sul, Av. Bento Gonçalves 9500, CP 15051, CEP 91501-970, Porto Alegre, RS, Brazil.
| | - Johnny Ferraz Dias
- Ion Implantation Laboratory, Institute of Physics, Federal University of Rio Grande do Sul, Av. Bento Gonçalves 9500, CP 15051, CEP 91501-970, Porto Alegre, RS, Brazil.
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31
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The anticancer estrogen receptor antagonist tamoxifen impairs consolidation of inhibitory avoidance memory through estrogen receptor alpha. J Neural Transm (Vienna) 2017; 124:1331-1339. [DOI: 10.1007/s00702-017-1785-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 08/27/2017] [Indexed: 12/20/2022]
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32
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Roesler R. Molecular mechanisms controlling protein synthesis in memory reconsolidation. Neurobiol Learn Mem 2017; 142:30-40. [DOI: 10.1016/j.nlm.2017.04.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 04/27/2017] [Accepted: 04/28/2017] [Indexed: 10/19/2022]
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33
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Valiati FE, Vasconcelos M, Lichtenfels M, Petry FS, de Almeida RMM, Schwartsmann G, Schröder N, de Farias CB, Roesler R. Administration of a Histone Deacetylase Inhibitor into the Basolateral Amygdala Enhances Memory Consolidation, Delays Extinction, and Increases Hippocampal BDNF Levels. Front Pharmacol 2017; 8:415. [PMID: 28701956 PMCID: PMC5487430 DOI: 10.3389/fphar.2017.00415] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 06/13/2017] [Indexed: 01/28/2023] Open
Abstract
Gene expression related to the formation and modification of memories is regulated epigenetically by chromatin remodeling through histone acetylation. Memory formation and extinction can be enhanced by treatment with inhibitors of histone deacetylases (HDACs). The basolateral amygdala (BLA) is a brain area critically involved in regulating memory for inhibitory avoidance (IA). However, previous studies have not examined the effects of HDAC inhibition in the amygdala on memory for IA. Here we show that infusion of an HDAC inhibitor (HDACi), trichostatin A (TSA), into the BLA, enhanced consolidation of IA memory in rats when given at 1.5, 3, or 6 h posttraining, but not when the drug was infused immediately after training. In addition, intra-BLA administration of TSA immediately after retrieval delayed extinction learning. Moreover, we show that intra-BLA TSA in rats given IA training increased the levels of brain-derived neurotrophic factor in the dorsal hippocampus, but not in the BLA itself. These findings reveal novel aspects of the regulation of fear memory by epigenetic mechanisms in the amygdala.
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Affiliation(s)
- Fernanda E Valiati
- Department of Pharmacology, Institute for Basic Health Sciences, Federal University of Rio Grande do SulPorto Alegre, Brazil.,Cancer and Neurobiology Laboratory, Experimental Research Center, Clinical Hospital, Federal University of Rio Grande do SulPorto Alegre, Brazil
| | - Mailton Vasconcelos
- Institute of Psychology, Federal University of Rio Grande do SulPorto Alegre, Brazil
| | - Martina Lichtenfels
- Cancer and Neurobiology Laboratory, Experimental Research Center, Clinical Hospital, Federal University of Rio Grande do SulPorto Alegre, Brazil
| | - Fernanda S Petry
- Department of Pharmacology, Institute for Basic Health Sciences, Federal University of Rio Grande do SulPorto Alegre, Brazil.,Cancer and Neurobiology Laboratory, Experimental Research Center, Clinical Hospital, Federal University of Rio Grande do SulPorto Alegre, Brazil
| | - Rosa M M de Almeida
- Institute of Psychology, Federal University of Rio Grande do SulPorto Alegre, Brazil
| | - Gilberto Schwartsmann
- Cancer and Neurobiology Laboratory, Experimental Research Center, Clinical Hospital, Federal University of Rio Grande do SulPorto Alegre, Brazil.,Department of Internal Medicine, Faculty of Medicine, Federal University of Rio Grande do SulPorto Alegre, Brazil
| | - Nadja Schröder
- Neurobiology and Developmental Biology Laboratory, Faculty of Biosciences, Pontifical Catholic University of Rio Grande do SulPorto Alegre, Brazil
| | - Caroline B de Farias
- Cancer and Neurobiology Laboratory, Experimental Research Center, Clinical Hospital, Federal University of Rio Grande do SulPorto Alegre, Brazil.,Children's Cancer InstitutePorto Alegre, Brazil
| | - Rafael Roesler
- Department of Pharmacology, Institute for Basic Health Sciences, Federal University of Rio Grande do SulPorto Alegre, Brazil.,Cancer and Neurobiology Laboratory, Experimental Research Center, Clinical Hospital, Federal University of Rio Grande do SulPorto Alegre, Brazil
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The intestinal TORC2 signaling pathway contributes to associative learning in Caenorhabditis elegans. PLoS One 2017; 12:e0177900. [PMID: 28542414 PMCID: PMC5444632 DOI: 10.1371/journal.pone.0177900] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 05/04/2017] [Indexed: 12/25/2022] Open
Abstract
Several types of associative learning are dependent upon the presence or absence of food, and are crucial for the survival of most animals. Target of rapamycin (TOR), a kinase which exists as a component of two complexes, TOR complex 1 (TORC1) and TOR complex 2 (TORC2), is known to act as a nutrient sensor in numerous organisms. However, the in vivo roles of TOR signaling in the nervous system remain largely unclear, partly because its multifunctionality and requirement for survival make it difficult to investigate. Here, using pharmacological inhibitors and genetic analyses, we show that TORC1 and TORC2 contribute to associative learning between salt and food availability in the nematode Caenorhabditis elegans in a process called taste associative learning. Worms migrate to salt concentrations experienced previously during feeding, but they avoid salt concentrations experienced under starvation conditions. Administration of the TOR inhibitor rapamycin causes a behavioral defect after starvation conditioning. Worms lacking either RICT-1 or SINH-1, two TORC2 components, show defects in migration to high salt levels after learning under both fed and starved conditions. We also analyzed the behavioral phenotypes of mutants of the putative TORC1 substrate RSKS-1 (the C. elegans homolog of the mammalian S6 kinase S6K) and the putative TORC2 substrates SGK-1 and PKC-2 (homologs of the serum and glucocorticoid-induced kinase 1, SGK1, and protein kinase C-α, PKC-α, respectively) and found that neuronal RSKS-1 and PKC-2, as well as intestinal SGK-1, are involved in taste associative learning. Our findings shed light on the functions of TOR signaling in behavioral plasticity and provide insight into the mechanisms by which information sensed in the intestine affects the nervous system to modulate food-searching behaviors.
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35
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Zubedat S, Akirav I. The involvement of cannabinoids and mTOR in the reconsolidation of an emotional memory in the hippocampal-amygdala-insular circuit. Eur Neuropsychopharmacol 2017; 27:336-349. [PMID: 28131675 DOI: 10.1016/j.euroneuro.2017.01.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 11/13/2016] [Accepted: 01/05/2017] [Indexed: 12/20/2022]
Abstract
Memory reconsolidation is the process in which reactivated long-term memory becomes transiently sensitive to amnesic agents. We evaluated the ability of post reactivation administration of the mTOR inhibitor rapamycin, separately and in combination with the cannabinoid CB1/2 receptor agonist WIN55,212-2 (WIN), given systemically or specifically into the hippocampal CA1 area, basolateral amygdala (BLA) or insular cortex (IC), to reduce inhibitory avoidance fear in rats. Systemic administration of rapamycin after reactivation of fear memory impaired reconsolidation and facilitated extinction. A combined treatment with WIN and rapamycin resulted in similar effects. WIN injected systemically facilitated extinction, with no effect on reconsolidation. WIN alone and with rapamycin also decreased anxiety-like behavior. Further, when spontaneous recovery was tested, the WIN+rapamycin group did not demonstrate recovery of fear which can occur spontaneously after the passage of time. Rapamycin and WIN had differential effects on reconsolidation and extinction when microinjected into the CA1, BLA and IC. Furthermore, exposure to shock increased p70s6K activation in the BLA, indicating activation by mTOR. Treatment with rapamycin, WIN or WIN+rapamycin decreased activation and there was a strong positive correlation between fear retrieval and p70s6K activation in the BLA, suggesting that enhanced fear retrieval is associated with enhanced p70s6K activation. Taken together, the results suggest that rapamycin or a combined treatment that involves blocking mTOR and activating cannabinoids may be a promising pharmacological approach for the attenuation of reactivated emotional memories, and thus, it could represent a potential treatment strategy for disorders associated with traumatic memories.
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Affiliation(s)
- Salman Zubedat
- Department of Psychology, University of Haifa, Haifa 3498838, Israel
| | - Irit Akirav
- Department of Psychology, University of Haifa, Haifa 3498838, Israel.
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36
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Lloyd BA, Hake HS, Ishiwata T, Farmer CE, Loetz EC, Fleshner M, Bland ST, Greenwood BN. Exercise increases mTOR signaling in brain regions involved in cognition and emotional behavior. Behav Brain Res 2017; 323:56-67. [PMID: 28130174 DOI: 10.1016/j.bbr.2017.01.033] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/11/2017] [Accepted: 01/18/2017] [Indexed: 12/21/2022]
Abstract
Exercise can enhance learning and memory and produce resistance against stress-related psychiatric disorders such as depression and anxiety. In rats, these beneficial effects of exercise occur regardless of exercise controllability: both voluntary and forced wheel running produce stress-protective effects. The mechanisms underlying these beneficial effects of exercise remain unknown. The mammalian target of rapamycin (mTOR) is a translation regulator important for cell growth, proliferation, and survival. mTOR has been implicated in enhancing learning and memory as well as antidepressant effects. Moreover, mTOR is sensitive to exercise signals such as metabolic factors. The effects of exercise on mTOR signaling, however, remain unknown. The goal of the present study was to test the hypothesis that exercise, regardless of controllability, increases levels of phosphorylated mTOR (p-mTOR) in brain regions important for learning and emotional behavior. Rats were exposed to 6 weeks of either sedentary (locked wheel), voluntary, or forced wheel running conditions. At 6 weeks, rats were sacrificed during peak running and levels of p-mTOR were measured using immunohistochemistry. Overall, both voluntary and forced exercise increased p-mTOR-positive neurons in the medial prefrontal cortex, striatum, hippocampus, hypothalamus, and amygdala compared to locked wheel controls. Exercise, regardless of controllability, also increased numbers of p-mTOR-positive glia in the striatum, hippocampus, and amygdala. For both neurons and glia, the largest increase in p-mTOR positive cells was observed after voluntary running, with forced exercise causing a more modest increase. Interestingly, voluntary exercise preferentially increased p-mTOR in astrocytes (GFAP+), while forced running increased p-mTOR in microglia (CD11+) in the inferior dentate gyrus. Results suggest that mTOR signaling is sensitive to exercise, but subtle differences exist depending on exercise controllability. Increases in mTOR signaling could contribute to the beneficial effects of exercise on cognitive function and mental health.
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Affiliation(s)
- Brian A Lloyd
- Department of Psychology, University of Colorado Denver, United States
| | - Holly S Hake
- Department of Psychology, University of Colorado Denver, United States
| | | | - Caroline E Farmer
- Department of Psychology, University of Colorado Denver, United States
| | - Esteban C Loetz
- Department of Psychology, University of Colorado Denver, United States
| | - Monika Fleshner
- Department of Integrative Physiology and Center for Neuroscience, University of Colorado Boulder, United States
| | - Sondra T Bland
- Department of Psychology, University of Colorado Denver, United States
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Garza-Lombó C, Gonsebatt ME. Mammalian Target of Rapamycin: Its Role in Early Neural Development and in Adult and Aged Brain Function. Front Cell Neurosci 2016; 10:157. [PMID: 27378854 PMCID: PMC4910040 DOI: 10.3389/fncel.2016.00157] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 05/30/2016] [Indexed: 01/14/2023] Open
Abstract
The kinase mammalian target of rapamycin (mTOR) integrates signals triggered by energy, stress, oxygen levels, and growth factors. It regulates ribosome biogenesis, mRNA translation, nutrient metabolism, and autophagy. mTOR participates in various functions of the brain, such as synaptic plasticity, adult neurogenesis, memory, and learning. mTOR is present during early neural development and participates in axon and dendrite development, neuron differentiation, and gliogenesis, among other processes. Furthermore, mTOR has been shown to modulate lifespan in multiple organisms. This protein is an important energy sensor that is present throughout our lifetime its role must be precisely described in order to develop therapeutic strategies and prevent diseases of the central nervous system. The aim of this review is to present our current understanding of the functions of mTOR in neural development, the adult brain and aging.
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Affiliation(s)
- Carla Garza-Lombó
- Departamento de Medicina Genómica, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México México
| | - María E Gonsebatt
- Departamento de Medicina Genómica, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México México
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Han Y, Luo Y, Sun J, Ding Z, Liu J, Yan W, Jian M, Xue Y, Shi J, Wang JS, Lu L. AMPK Signaling in the Dorsal Hippocampus Negatively Regulates Contextual Fear Memory Formation. Neuropsychopharmacology 2016; 41:1849-64. [PMID: 26647974 PMCID: PMC4869054 DOI: 10.1038/npp.2015.355] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 11/08/2015] [Accepted: 12/01/2015] [Indexed: 12/12/2022]
Abstract
Both the formation of long-term memory (LTM) and dendritic spine growth that serves as a physical basis for the long-term storage of information require de novo protein synthesis. Memory formation also critically depends on transcription. Adenosine monophosphate-activated protein kinase (AMPK) is a transcriptional regulator that has emerged as a major energy sensor that maintains cellular energy homeostasis. However, still unknown is its role in memory formation. In the present study, we found that AMPK is primarily expressed in neurons in the hippocampus, and then we demonstrated a time-dependent decrease in AMPK activity and increase in mammalian target of rapamycin complex 1 (mTORC1) activity after contextual fear conditioning in the CA1 but not CA3 area of the dorsal hippocampus. Using pharmacological methods and adenovirus gene transfer to bidirectionally regulate AMPK activity, we found that increasing AMPK activity in the CA1 impaired the formation of long-term fear memory, and decreasing AMPK activity enhanced fear memory formation. These findings were associated with changes in the phosphorylation of AMPK and p70s6 kinase (p70s6k) and expression of BDNF and membrane GluR1 and GluR2 in the CA1. Furthermore, the prior administration of an mTORC1 inhibitor blocked the enhancing effect of AMPK inhibition on fear memory formation, suggesting that this negative regulation of contextual fear memory by AMPK in the CA1 depends on the mTORC1 signaling pathway. Finally, we found that AMPK activity regulated hippocampal spine growth associated with memory formation. In summary, our results indicate that AMPK is a key negative regulator of plasticity and fear memory formation.
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Affiliation(s)
- Ying Han
- Institute of Mental Health/Peking University Sixth Hospital and Key Laboratory of Mental Health, Beijing, China,National Institute on Drug Dependence and Beijing Key Laboratory of Drug Dependence, Peking University, Beijing, China,Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Yixiao Luo
- Department of Pharmacy, Medical College, Hunan Normal University, Changsha, China
| | - Jia Sun
- Department of Hematology, Affiliated Hospital of Guiyang Medical University, Guiyang, China
| | - Zengbo Ding
- National Institute on Drug Dependence and Beijing Key Laboratory of Drug Dependence, Peking University, Beijing, China
| | - Jianfeng Liu
- Department of Pharmacology and Toxicology, University of Buffalo, State University of New York, Buffalo, NY, USA
| | - Wei Yan
- Institute of Mental Health/Peking University Sixth Hospital and Key Laboratory of Mental Health, Beijing, China,National Institute on Drug Dependence and Beijing Key Laboratory of Drug Dependence, Peking University, Beijing, China
| | - Min Jian
- Institute of Mental Health/Peking University Sixth Hospital and Key Laboratory of Mental Health, Beijing, China,National Institute on Drug Dependence and Beijing Key Laboratory of Drug Dependence, Peking University, Beijing, China
| | - Yanxue Xue
- National Institute on Drug Dependence and Beijing Key Laboratory of Drug Dependence, Peking University, Beijing, China
| | - Jie Shi
- National Institute on Drug Dependence and Beijing Key Laboratory of Drug Dependence, Peking University, Beijing, China
| | - Ji-Shi Wang
- Department of Hematology, Affiliated Hospital of Guiyang Medical University, Guiyang, China,Department of Hematology, Affiliated Hospital of Guiyang Medical University, Guiyang 550004, China, E-mail:
| | - Lin Lu
- Institute of Mental Health/Peking University Sixth Hospital and Key Laboratory of Mental Health, Beijing, China,National Institute on Drug Dependence and Beijing Key Laboratory of Drug Dependence, Peking University, Beijing, China,Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, China,Institute of Mental Health, Peking University, 51 Huayuan Bei Road, Beijing 100191, China, Tel: +86 10 82805308, Fax: +86 10 62032624, E-mail:
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Lu B, Jiang J, Sun J, Xiao C, Meng B, Zheng J, Li X, Wang R, Wu G, Chen J. Inhibition of mammalian target of rapamycin activation in the rostral anterior cingulate cortex attenuates pain-related aversion in rats. Behav Brain Res 2016; 310:51-8. [PMID: 27163752 DOI: 10.1016/j.bbr.2016.05.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 04/12/2016] [Accepted: 05/04/2016] [Indexed: 10/21/2022]
Abstract
Pain is a complex experience that comprises both sensory and affective dimensions. Mammalian target of rapamycin (mTOR) plays an important role in the modulation of neuronal plasticity associated with the pathogenesis of pain sensation. However, the role of mTOR in pain affect is unclear. Using a formalin-induced conditioned place avoidance (F-CPA) test, the current study investigated the effects of the mTOR specific inhibitor rapamycin on noxious stimulation induced aversion in the rostral anterior cingulate cortex (rACC). Intraplantar injection of 5% formalin was associated with significant activation of mTOR, as well as p70 ribosomal S6 protein (p70S6K), its downstream effector, in the rACC. The inhibition of mTOR activation with rapamycin disrupted pain-related aversion; however, this inhibition did not affect formalin-induced spontaneous nociceptive behaviors in rats. These findings demonstrated for the first time that mTOR and its downstream pathway in the rACC contribute to the induction of pain-related negative emotion.
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Affiliation(s)
- Bo Lu
- Department of Anesthesia, Ningbo NO. 2 Hospital, Ningbo 315010, PR China
| | - Jingyan Jiang
- Department of Anesthesia, Yinzhou Hospital Affiliated to Medical School of Ningbo University, Ningbo 315040, PR China
| | - Jianliang Sun
- Department of Anesthesia, Hangzhou Hospital Affiliated to Nanjing Medical University, Hangzhou First People's Hospital, Hangzhou 310006, PR China
| | - Chun Xiao
- Department of Anesthesia, Hangzhou Hospital Affiliated to Nanjing Medical University, Hangzhou First People's Hospital, Hangzhou 310006, PR China
| | - Bo Meng
- Department of Anesthesia, Ningbo NO. 2 Hospital, Ningbo 315010, PR China
| | - Jinwei Zheng
- Department of Anesthesia, Ningbo NO. 2 Hospital, Ningbo 315010, PR China
| | - Xiaoyu Li
- Department of Anesthesia, Ningbo NO. 2 Hospital, Ningbo 315010, PR China
| | - Ruichun Wang
- Department of Anesthesia, Ningbo NO. 2 Hospital, Ningbo 315010, PR China
| | - Guorong Wu
- Department of Anesthesia, Ningbo NO. 2 Hospital, Ningbo 315010, PR China
| | - Junping Chen
- Department of Anesthesia, Ningbo NO. 2 Hospital, Ningbo 315010, PR China.
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Villain H, Benkahoul A, Drougard A, Lafragette M, Muzotte E, Pech S, Bui E, Brunet A, Birmes P, Roullet P. Effects of Propranolol, a β-noradrenergic Antagonist, on Memory Consolidation and Reconsolidation in Mice. Front Behav Neurosci 2016; 10:49. [PMID: 27014009 PMCID: PMC4789536 DOI: 10.3389/fnbeh.2016.00049] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 02/29/2016] [Indexed: 12/20/2022] Open
Abstract
Memory reconsolidation impairment using the β-noradrenergic receptor blocker propranolol is a promising novel treatment avenue for patients suffering from pathogenic memories, such as post-traumatic stress disorder (PTSD). However, in order to better inform targeted treatment development, the effects of this compound on memory need to be better characterized via translational research. We examined the effects of systemic propranolol administration in mice undergoing a wide range of behavioral tests to determine more specifically which aspects of the memory consolidation and reconsolidation are impaired by propranolol. We found that propranolol (10 mg/kg) affected memory consolidation in non-aversive tasks (object recognition and object location) but not in moderately (Morris water maze (MWM) to highly (passive avoidance, conditioned taste aversion) aversive tasks. Further, propranolol impaired memory reconsolidation in the most and in the least aversive tasks, but not in the moderately aversive task, suggesting its amnesic effect was not related to task aversion. Moreover, in aquatic object recognition and location tasks in which animals were forced to behave (contrary to the classic versions of the tasks); propranolol did not impair memory reconsolidation. Taken together our results suggest that the memory impairment observed after propranolol administration may result from a modification of the emotional valence of the memory rather than a disruption of the contextual component of the memory trace. This is relevant to the use of propranolol to block memory reconsolidation in individuals with PTSD, as such a treatment would not erase the traumatic memory but only reduce the emotional valence associated with this event.
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Affiliation(s)
- Hélène Villain
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier (UPS) Toulouse, France
| | - Aïcha Benkahoul
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier (UPS) Toulouse, France
| | - Anne Drougard
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier (UPS) Toulouse, France
| | - Marie Lafragette
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier (UPS) Toulouse, France
| | - Elodie Muzotte
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier (UPS) Toulouse, France
| | - Stéphane Pech
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier (UPS) Toulouse, France
| | - Eric Bui
- Department of Psychiatry, Massachusetts General Hospital & Harvard Medical School Boston, MA, USA
| | - Alain Brunet
- Department of Psychiatry, Douglas Mental Health University Institute and McGill University Montréal, QC, Canada
| | - Philippe Birmes
- Toulouse NeuroImaging Center, Université de Toulouse, Institut national de la santé et de la recherche médicale (INSERM), Université Paul Sabatier (UPS) Toulouse, France
| | - Pascal Roullet
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier (UPS) Toulouse, France
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Girardi BA, Ribeiro DA, Signor C, Muller M, Gais MA, Mello CF, Rubin MA. Spermidine-induced improvement of reconsolidation of memory involves calcium-dependent protein kinase in rats. ACTA ACUST UNITED AC 2015; 23:21-8. [PMID: 26670183 PMCID: PMC4749837 DOI: 10.1101/lm.039396.115] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 10/28/2015] [Indexed: 11/24/2022]
Abstract
In this study, we determined whether the calcium-dependent protein kinase (PKC) signaling pathway is involved in the improvement of fear memory reconsolidation induced by the intrahippocampal administration of spermidine in rats. Male Wistar rats were trained in a fear conditioning apparatus using a 0.4-mA footshock as an unconditioned stimulus. Twenty-four hours after training, animals were re-exposed to the apparatus in the absence of shock (reactivation session). Immediately after the reactivation session, spermidine (2–200 pmol/site), the PKC inhibitor 3-[1-(dimethylaminopropyl)indol-3-yl]-4-(indol-3-yl) maleimide hydrochloride (GF 109203X, 0.3–30 pg/site), the antagonist of the polyamine-binding site at the NMDA receptor, arcaine (0.2–200 pmol/site), or the PKC activator phorbol 12-myristate 13-acetate (PMA, 0.02–2 nmol/site) was injected. While the post-reactivation administration of spermidine (20 and 200 pmol/site) and PMA (2 nmol/site) improved memory reconsolidation, GF 109203X (1, 10, and 30 pg/site) and arcaine (200 pmol/site) impaired it. GF 109203X (0.3 pg/site) impaired memory reconsolidation in the presence of spermidine (200 pmol/site). PMA (0.2 nmol/site) prevented the arcaine (200 pmol/site)-induced impairment of memory reconsolidation. Anisomycin (2 µg/site) also impaired memory reconsolidation in the presence of spermidine (200 pmol/site). Drugs had no effect when they were administered in the absence of reactivation. These results suggest that the spermidine-induced enhancement of memory reconsolidation involves PKC activation.
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Affiliation(s)
- Bruna Amanda Girardi
- Graduate Program in Pharmacology, Center of Health Sciences, Federal University of Santa Maria, Santa Maria, RS 97105-900, Brazil
| | - Daniela Aymone Ribeiro
- Graduate Program in Biological Sciences: Toxicological Biochemistry, Center of Exact and Natural Sciences, Federal University of Santa Maria, Santa Maria, RS 97105-900, Brazil
| | - Cristiane Signor
- Graduate Program in Biological Sciences: Toxicological Biochemistry, Center of Exact and Natural Sciences, Federal University of Santa Maria, Santa Maria, RS 97105-900, Brazil
| | - Michele Muller
- Undergraduate in Pharmacy, Center of Health Sciences, Federal University of Santa Maria, Santa Maria, RS 97105-900, Brazil
| | - Mayara Ana Gais
- Undergraduate in Pharmacy, Center of Health Sciences, Federal University of Santa Maria, Santa Maria, RS 97105-900, Brazil
| | - Carlos Fernando Mello
- Graduate Program in Pharmacology, Center of Health Sciences, Federal University of Santa Maria, Santa Maria, RS 97105-900, Brazil
| | - Maribel Antonello Rubin
- Graduate Program in Pharmacology, Center of Health Sciences, Federal University of Santa Maria, Santa Maria, RS 97105-900, Brazil Graduate Program in Biological Sciences: Toxicological Biochemistry, Center of Exact and Natural Sciences, Federal University of Santa Maria, Santa Maria, RS 97105-900, Brazil
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42
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Blank M, Petry FS, Lichtenfels M, Valiati FE, Dornelles AS, Roesler R. TrkB blockade in the hippocampus after training or retrieval impairs memory: protection from consolidation impairment by histone deacetylase inhibition. J Neural Transm (Vienna) 2015; 123:159-65. [DOI: 10.1007/s00702-015-1464-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 09/16/2015] [Indexed: 01/07/2023]
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43
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Crestani AP, Zacouteguy Boos F, Haubrich J, Ordoñez Sierra R, Santana F, Molina JMD, Cassini LDF, Alvares LDO, Quillfeldt JA. Memory reconsolidation may be disrupted by a distractor stimulus presented during reactivation. Sci Rep 2015; 5:13633. [PMID: 26328547 PMCID: PMC4556962 DOI: 10.1038/srep13633] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 08/03/2015] [Indexed: 12/27/2022] Open
Abstract
Memories can be destabilized by the reexposure to the training context, and may reconsolidate into a modified engram. Reconsolidation relies on some particular molecular mechanisms involving LVGCCs and GluN2B-containing NMDARs. In this study we investigate the interference caused by the presence of a distractor - a brief, unanticipated stimulus that impair a fear memory expression - during the reactivation session, and tested the hypothesis that this disruptive effect relies on a reconsolidation process. Rats previously trained in the contextual fear conditioning (CFC) were reactivated in the presence or absence of a distractor stimulus. In the test, groups reactivated in the original context with distractor displayed a reduction of the freezing response lasting up to 20 days. To check for the involvement of destabilization / reconsolidation mechanisms, we studied the effect of systemic nimodipine (a L-VGCC blocker) or intra-CA1 ifenprodil (a selective GluN2B/NMDAR antagonist) infused right before the reactivation session. Both treatments were able to prevent the disruptive effect of distraction. Ifenprodil results also bolstered the case for hippocampus as the putative brain structure hosting this phenomenon. Our results provide some evidence in support of a behavioral, non-invasive procedure that was able to disrupt an aversive memory in a long-lasting way.
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Affiliation(s)
- Ana Paula Crestani
- Psychobiology and Neurocomputation Lab, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.,Neurosciences Graduate Program, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Flávia Zacouteguy Boos
- Psychobiology and Neurocomputation Lab, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.,Neurosciences Graduate Program, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Josué Haubrich
- Psychobiology and Neurocomputation Lab, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.,Neurosciences Graduate Program, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Rodrigo Ordoñez Sierra
- Psychobiology and Neurocomputation Lab, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.,Neurosciences Graduate Program, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Fabiana Santana
- Psychobiology and Neurocomputation Lab, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.,Neurosciences Graduate Program, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Johanna Marcela Duran Molina
- Psychobiology and Neurocomputation Lab, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.,Neurosciences Graduate Program, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Lindsey de Freitas Cassini
- Psychobiology and Neurocomputation Lab, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.,Neurosciences Graduate Program, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Lucas de Oliveira Alvares
- Psychobiology and Neurocomputation Lab, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.,Neurosciences Graduate Program, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Jorge Alberto Quillfeldt
- Psychobiology and Neurocomputation Lab, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.,Neurosciences Graduate Program, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
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Frazier TW, Embacher R, Tilot AK, Koenig K, Mester J, Eng C. Molecular and phenotypic abnormalities in individuals with germline heterozygous PTEN mutations and autism. Mol Psychiatry 2015; 20:1132-8. [PMID: 25288137 PMCID: PMC4388743 DOI: 10.1038/mp.2014.125] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 08/07/2014] [Accepted: 08/28/2014] [Indexed: 12/30/2022]
Abstract
PTEN is a tumor suppressor associated with an inherited cancer syndrome and an important regulator of ongoing neural connectivity and plasticity. The present study examined molecular and phenotypic characteristics of individuals with germline heterozygous PTEN mutations and autism spectrum disorder (ASD) (PTEN-ASD), with the aim of identifying pathophysiologic markers that specifically associate with PTEN-ASD and that may serve as targets for future treatment trials. PTEN-ASD patients (n=17) were compared with idiopathic (non-PTEN) ASD patients with (macro-ASD, n=16) and without macrocephaly (normo-ASD, n=38) and healthy controls (n=14). Group differences were evaluated for PTEN pathway protein expression levels, global and regional structural brain volumes and cortical thickness measures, neurocognition and adaptive behavior. RNA expression patterns and brain characteristics of a murine model of Pten mislocalization were used to further evaluate abnormalities observed in human PTEN-ASD patients. PTEN-ASD had a high proportion of missense mutations and showed reduced PTEN protein levels. Compared with the other groups, prominent white-matter and cognitive abnormalities were specifically associated with PTEN-ASD patients, with strong reductions in processing speed and working memory. White-matter abnormalities mediated the relationship between PTEN protein reductions and reduced cognitive ability. The Pten(m3m4) murine model had differential expression of genes related to myelination and increased corpus callosum. Processing speed and working memory deficits and white-matter abnormalities may serve as useful features that signal clinicians that PTEN is etiologic and prompting referral to genetic professionals for gene testing, genetic counseling and cancer risk management; and could reveal treatment targets in trials of treatments for PTEN-ASD.
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Baldi E, Bucherelli C. Brain sites involved in fear memory reconsolidation and extinction of rodents. Neurosci Biobehav Rev 2015; 53:160-90. [DOI: 10.1016/j.neubiorev.2015.04.003] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 03/30/2015] [Accepted: 04/06/2015] [Indexed: 12/21/2022]
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Grados M, Sung HM, Kim S, Srivastava S. Genetic findings in obsessive-compulsive disorder connect to brain-derived neutrophic factor and mammalian target of rapamycin pathways: implications for drug development. Drug Dev Res 2015; 75:372-83. [PMID: 25195581 DOI: 10.1002/ddr.21223] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Traditional pharmacological approaches to the treatment of obsessive-compulsive disorder (OCD) are based on affecting serotonergic and dopaminergic transmission in the central nervous system. However, genetic epidemiology findings are pointing to glutamate pathways and developmental genes as etiological in OCD. A review of recent genetic findings in OCD is conducted, and bioinformatics approaches are used to locate pathways relevant to neuroprotection. The OCD susceptibility genes DLGAP1, RYR3, PBX1-MEIS2, LMX1A and candidate genes BDNF and GRIN2B are components of the neuronal growth, differentiation and neurogenesis pathways BDNF-mTOR. These pathways are emerging as a promising area of research for the development of neuroprotective pharmaceuticals. Emergent genetic epidemiologic data on OCD and repetitive behaviors may support new approaches for pharmacological discovery. Neuroprotective approaches that take into consideration glutamate-mediated BDNF-mTOR pathways are suggested by OCD susceptibility genes.
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Affiliation(s)
- Marco Grados
- Division of Child & Adolescent Psychiatry, Johns Hopkins University School of Medicine, 1800 Orleans St.-12th floor, Baltimore, MD, 21287, USA
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47
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Memory retrieval requires ongoing protein synthesis and NMDA receptor activity-mediated AMPA receptor trafficking. J Neurosci 2015; 35:2465-75. [PMID: 25673841 DOI: 10.1523/jneurosci.0735-14.2015] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Whereas consolidation and reconsolidation are considered dynamic processes requiring protein synthesis, memory retrieval has long been considered a passive readout of previously established plasticity. However, previous findings suggest that memory retrieval may be more dynamic than previously thought. This study therefore aimed at investigating the molecular mechanisms underlying memory retrieval in the rat. Infusion of protein synthesis inhibitors (rapamycin or anisomycin) in the amygdala 10 min before memory retrieval transiently impaired auditory fear memory expression, suggesting ongoing protein synthesis is required to enable memory retrieval. We then investigated the role of protein synthesis in NMDA receptor activity-mediated AMPA receptor trafficking. Coinfusion of an NMDA receptor antagonist (ifenprodil) or infusion of an AMPA receptor endocytosis inhibitor (GluA23Y) before rapamycin prevented this memory impairment. Furthermore, rapamycin transiently decreased GluA1 levels at the postsynaptic density (PSD), but did not affect extrasynaptic sites. This effect at the PSD was prevented by an infusion of GluA23Y before rapamycin. Together, these data show that ongoing protein synthesis is required before memory retrieval is engaged, and suggest that this protein synthesis may be involved in the NMDAR activity-mediated trafficking of AMPA receptors that takes place during memory retrieval.
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48
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Fifield K, Hebert M, Williams K, Linehan V, Whiteman JD, Mac Callum P, Blundell J. Time-dependent effects of rapamycin on consolidation of predator stress-induced hyperarousal. Behav Brain Res 2015; 286:104-11. [PMID: 25746515 DOI: 10.1016/j.bbr.2015.02.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 02/19/2015] [Accepted: 02/24/2015] [Indexed: 01/26/2023]
Abstract
Previous studies have indicated that rapamycin, a potent inhibitor of the mammalian target of rapamycin (mTOR) pathway, blocks consolidation of shock-induced associative fear memories. Moreover, rapamycin's block of associative fear memories is time-dependent. It is unknown, however, if rapamycin blocks consolidation of predator stress-induced non-associative fear memories. Furthermore, the temporal pattern of mTOR activation following predator stress is unknown. Thus, the goal of the current studies was to determine if rapamycin blocks consolidation of predator stress-induced fear memories and if so, whether rapamycin's effect is time-dependent. Male rats were injected systemically with rapamycin at various time points following predator stress. Predator stress involves an acute, unprotected exposure of a rat to a cat, which causes long-lasting non-associative fear memories manifested as generalized hyperarousal and increased anxiety-like behaviour. We show that rapamycin injected immediately after predator stress blocked consolidation of stress-induced startle. However, rapamycin injected 9, 24 or 48h post predator stress potentiated stress-induced startle. Consistent with shock-induced associative fear memories, we show that mTOR signalling is essential for consolidation of predator stress-induced hyperarousal. However, unlike shock-induced fear memories, a second, persistent, late phase mTOR-dependent process following predator stress actually dampens startle. Consistent with previous findings, our data support the potential role for rapamycin in treatment of stress related disorders such as posttraumatic stress disorder. However, our data suggest timing of rapamycin administration is critical.
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Affiliation(s)
- Kathleen Fifield
- Department of Psychology, Memorial University of Newfoundland, 232 Elizabeth Ave. , St. John's, Newfoundland, Canada A1B 3X9
| | - Mark Hebert
- Department of Psychology, Memorial University of Newfoundland, 232 Elizabeth Ave. , St. John's, Newfoundland, Canada A1B 3X9
| | - Kimberly Williams
- Department of Psychology, Memorial University of Newfoundland, 232 Elizabeth Ave. , St. John's, Newfoundland, Canada A1B 3X9
| | - Victoria Linehan
- Department of Psychology, Memorial University of Newfoundland, 232 Elizabeth Ave. , St. John's, Newfoundland, Canada A1B 3X9
| | - Jesse D Whiteman
- Department of Psychology, Memorial University of Newfoundland, 232 Elizabeth Ave. , St. John's, Newfoundland, Canada A1B 3X9
| | - Phillip Mac Callum
- Department of Psychology, Memorial University of Newfoundland, 232 Elizabeth Ave. , St. John's, Newfoundland, Canada A1B 3X9
| | - Jacqueline Blundell
- Department of Psychology, Memorial University of Newfoundland, 232 Elizabeth Ave. , St. John's, Newfoundland, Canada A1B 3X9.
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49
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Abstract
Many psychiatric disorders are characterized by intrusive, distracting, and disturbing memories that either perpetuate the illness or hinder successful treatment. For example, posttraumatic stress disorder (PTSD) involves such strong reemergence of memories associated with a traumatic event that the individual feels like the event is happening again. Furthermore, drug addiction is characterized by compulsive use and repeated relapse that is often driven by internal memories of drug use and/or by exposure to external stimuli that were associated with drug use. Therefore, identifying pharmacological methods to weaken the strength of maladaptive memories is a major goal of research efforts aimed at finding new treatments for these disorders. The primary mechanism by which memories could be pharmacologically disrupted or altered is through manipulation of memory reconsolidation. Reconsolidation occurs when an established memory is remembered or reactivated, reentering a labile state before again being consolidated into long-term memory storage. Memories are subject to disruption during this labile state. In this chapter we will discuss the preclinical and clinical studies identifying potential pharmacological methods for disrupting the integrity of maladaptive memory to treat mental illness.
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Affiliation(s)
- Jane R Taylor
- Department of Psychiatry, Yale University, New Haven, CT, USA
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Requirement of Mammalian target of rapamycin complex 1 downstream effectors in cued fear memory reconsolidation and its persistence. J Neurosci 2014; 34:9034-9. [PMID: 24990923 DOI: 10.1523/jneurosci.0878-14.2014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Memory retrieval, often termed reconsolidation, can render previously consolidated memories susceptible to manipulation that can lead to alterations in memory strength. Although it is known that reconsolidation requires mammalian target of rapamycin complex 1 (mTORC1)-dependent translation, the specific contributions of its downstream effectors in reconsolidation are unclear. Using auditory fear conditioning in mice, we investigated the role of eukaryotic translation initiation factor 4E (eIF4E)-eIF4G interactions and p70 S6 kinase polypeptide 1 (S6K1) in reconsolidation. We found that neither 4EGI-1 (2-[(4-(3,4-dichlorophenyl)-thiazol-2-ylhydrazono)-3-(2-nitrophenyl)]propionic acid), an inhibitor of eFI4E-eIF4G interactions, nor PF-4708671 [2-((4-(5-ethylpyrimidin-4-yl)piperazin-1-yl)methyl)-5-(trifluoromethyl)-1H-benzo[d]imidazole], an inhibitor of S6K1, alone blocked the reconsolidation of auditory fear memory. In contrast, using these drugs in concert to simultaneously block eIF4E-eIF4G interactions and S6K1 immediately after memory reactivation significantly attenuated fear memory reconsolidation. Moreover, the combination of 4EGI-1 and PF-4708671 further destabilized fear memory 10 d after memory reactivation, which was consistent with experiments using rapamycin, an mTORC1 inhibitor. Furthermore, inhibition of S6K1 immediately after retrieval resulted in memory destabilization 10 d after reactivation, whereas inhibition of eIF4E-eIF4G interactions did not. These results indicate that the reconsolidation of fear memory requires concomitant association of eIF4E to eIF4G as well as S6K1 activity and that the persistence of memory at longer intervals after memory reactivation also requires mTORC1-dependent processes that involve S6K1. These findings suggest a potential mechanism for how mTORC1-dependent translation is fine tuned to alter memory persistence.
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