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Stefanik MT, Sakas C, Lee D, Wolf ME. Ionotropic and metabotropic glutamate receptors regulate protein translation in co-cultured nucleus accumbens and prefrontal cortex neurons. Neuropharmacology 2018; 140:62-75. [PMID: 30077883 DOI: 10.1016/j.neuropharm.2018.05.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 05/15/2018] [Accepted: 05/29/2018] [Indexed: 01/14/2023]
Abstract
The regulation of protein translation by glutamate receptors and its role in plasticity have been extensively studied in the hippocampus. In contrast, very little is known about glutamatergic regulation of translation in nucleus accumbens (NAc) medium spiny neurons (MSN), despite their critical role in addiction-related plasticity and recent evidence that protein translation contributes to this plasticity. We used a co-culture system, containing NAc MSNs and prefrontal cortex (PFC) neurons, and fluorescent non-canonical amino acid tagging (FUNCAT) to visualize newly synthesized proteins in neuronal processes of NAc MSNs and PFC pyramidal neurons. First, we verified that the FUNCAT signal reflects new protein translation. Next, we examined the regulation of translation by group I metabotropic glutamate receptors (mGluRs) and ionotropic glutamate receptors by incubating co-cultures with agonists or antagonists during the 2-h period of non-canonical amino acid labeling. In NAc MSNs, basal translation was modestly reduced by blocking Ca2+-permeable AMPARs whereas blocking all AMPARs or suppressing constitutive mGluR5 signaling enhanced translation. Activating group I mGluRs with dihydroxyphenylglycine increased translation in an mGluR1-dependent manner in NAc MSNs and PFC pyramidal neurons. Disinhibiting excitatory transmission with bicuculline also increased translation. In MSNs, this was reversed by antagonists of mGluR1, mGluR5, AMPARs or NMDARs. In PFC neurons, AMPAR or NMDAR antagonists blocked bicuculline-stimulated translation. Our study, the first to examine glutamatergic regulation of translation in MSNs, demonstrates regulatory mechanisms specific to MSNs that depend on the level of neuronal activation. This sets the stage for understanding how translation may be altered in addiction.
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Affiliation(s)
- Michael T Stefanik
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064, USA
| | - Courtney Sakas
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064, USA
| | - Dennis Lee
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064, USA
| | - Marina E Wolf
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064, USA.
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Lozupone M, La Montagna M, D'Urso F, Piccininni C, Sardone R, Dibello V, Giannelli G, Solfrizzi V, Greco A, Daniele A, Quaranta N, Seripa D, Bellomo A, Logroscino G, Panza F. Pharmacotherapy for the treatment of depression in patients with alzheimer's disease: a treatment-resistant depressive disorder. Expert Opin Pharmacother 2018; 19:823-842. [PMID: 29726758 DOI: 10.1080/14656566.2018.1471136] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Pharmacotherapy for the treatment of depressive disorders in Alzheimer's Disease (AD) represents a clinical challenge. pharmacological options are often attempted after a period of watchful waiting (8-12 weeks). monoaminergic antidepressant drugs have shown only modest or null clinical benefits, maybe because the etiology of depressive symptoms in ad patients is fundamentally different from that of nondemented subjects. AREAS COVERED The following article looks at the selective serotonin reuptake inhibitor sertraline, which is one of the most frequently studied antidepressant medications in randomized controlled trials (RCTs). It also discusses many other pharmacological approaches that have proven to be inadequate (antipsychotics, acetylcholinesterase inhibitors, anticonvulsants, hormone replacement therapy) and new drug classes (mainly affecting glutamate transmission) that are being studied for treating depression in AD. It also gives discussion to the phase II RCT on the alternative drug S47445 and the potential effect on cognition of the multimodal antidepressant vortioxetine in older depressed patients. Finally, it discusses the N-methyl-D-aspartate antagonist ketamine. EXPERT OPINION The present RCT methodologies are too disparate to draw firm conclusions. Future studies are required to identify effective and multimodal pharmacological treatments that efficiently treat depression in AD. Genotyping may boost antidepressant treatment success.
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Affiliation(s)
- Madia Lozupone
- a Neurodegenerative Disease Unit, Department of Basic Medicine, Neuroscience, and Sense Organs , University of Bari Aldo Moro , Bari , Italy
| | - Maddalena La Montagna
- b Psychiatric Unit, Department of Clinical and Experimental Medicine , University of Foggia , Foggia , Italy
| | - Francesca D'Urso
- b Psychiatric Unit, Department of Clinical and Experimental Medicine , University of Foggia , Foggia , Italy
| | - Carla Piccininni
- b Psychiatric Unit, Department of Clinical and Experimental Medicine , University of Foggia , Foggia , Italy
| | - Rodolfo Sardone
- c Department of Epidemiology and Biostatistics , National Institute of Gastroenterology "S. de Bellis" Research Hospital , Castellana Grotte, Bari , Italy
| | - Vittorio Dibello
- d Interdisciplinary Department of Medicine (DIM), Section of Dentistry , University of Bari Aldo Moro , Bari , Italy
| | - Gianluigi Giannelli
- c Department of Epidemiology and Biostatistics , National Institute of Gastroenterology "S. de Bellis" Research Hospital , Castellana Grotte, Bari , Italy
| | - Vincenzo Solfrizzi
- e Geriatric Medicine-Memory Unit and Rare Disease Centre , University of Bari Aldo Moro , Bari , Italy
| | - Antonio Greco
- f Geriatric Unit & Laboratory of Gerontology and Geriatrics, Department of Medical Sciences , IRCCS "Casa Sollievo della Sofferenza" , San Giovanni Rotondo, Foggia , Italy
| | - Antonio Daniele
- g Institute of Neurology , Catholic University of Sacred Heart , Rome , Italy
| | - Nicola Quaranta
- h Otolaryngology Unit , University of Bari "Aldo Moro" , Bari , Italy
| | - Davide Seripa
- f Geriatric Unit & Laboratory of Gerontology and Geriatrics, Department of Medical Sciences , IRCCS "Casa Sollievo della Sofferenza" , San Giovanni Rotondo, Foggia , Italy
| | - Antonello Bellomo
- b Psychiatric Unit, Department of Clinical and Experimental Medicine , University of Foggia , Foggia , Italy
| | - Giancarlo Logroscino
- a Neurodegenerative Disease Unit, Department of Basic Medicine, Neuroscience, and Sense Organs , University of Bari Aldo Moro , Bari , Italy.,i Department of Clinical Research in Neurology , University of Bari Aldo Moro, "Pia Fondazione Cardinale G. Panico" , Tricase, Lecce , Italy
| | - Francesco Panza
- a Neurodegenerative Disease Unit, Department of Basic Medicine, Neuroscience, and Sense Organs , University of Bari Aldo Moro , Bari , Italy.,f Geriatric Unit & Laboratory of Gerontology and Geriatrics, Department of Medical Sciences , IRCCS "Casa Sollievo della Sofferenza" , San Giovanni Rotondo, Foggia , Italy.,i Department of Clinical Research in Neurology , University of Bari Aldo Moro, "Pia Fondazione Cardinale G. Panico" , Tricase, Lecce , Italy
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Ahmad F, Salahuddin M, Alsamman K, AlMulla AA, Salama KF. Developmental lead (Pb)-induced deficits in hippocampal protein translation at the synapses are ameliorated by ascorbate supplementation. Neuropsychiatr Dis Treat 2018; 14:3289-3298. [PMID: 30568451 PMCID: PMC6276627 DOI: 10.2147/ndt.s174083] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Lead (Pb) is a persistent environmental neurotoxin and its exposure even in minute quantities has been known to induce neuronal defects. The immature brain is singularly sensitive to Pb neurotoxicity, and its exposure during development has permanent detrimental effects on the brain developmental trajectory and neuronal signaling and plasticity, culminating into compromises in the cognitive and behavioral attributes which persists even later in adulthood. Several molecular pathways have been implicated in the Pb-mediated disruption of neuronal signaling, including elevated oxidative stress, alterations in neurotransmitter biology, and mitochondrial dysfunction. Nevertheless, the neuronal targets and biochemical pathways underlying these Pb-mediated alterations in synaptic development and function have not been completely deduced. In this respect, recent studies have shown that synaptic signaling and its maintenance and plasticity are critically dependent on localized de novo protein translation at the synaptic terminals. MATERIALS AND METHODS The present study hence aimed to assess the alterations in the synapse-specific translation induced by developmental Pb exposure. To this end, in vitro protein translation rate was analyzed in the hippocampal synaptoneurosomal fractions of rat pups pre- and postnatally exposed to Pb using a puromycin incorporation assay. Moreover, we evaluated the therapeutic effects of ascorbic acid supplementation against Pb-induced deficits in synapse-localized protein translation. RESULTS We observed a significant loss in the rates of de novo protein translation in synaptoneurosomes of Pb-exposed pups compared to age-matched control pups. Interestingly, ascorbate supplementation lead to an appreciable recovery in Pb-induced translational deficits. Moreover, the deficit in activity-dependent synaptic protein translation was found to correlate significantly with the increase in the blood Pb levels. CONCLUSION Dysregulation of synapse-localized de novo protein translation is a potentially critical determinant of Pb-induced synaptic dysfunction and the consequent deficits in behavioral, social, and psychological attributes of the organisms. In addition, our study establishes ascorbate supplementation as a key ameliorative agent against Pb-induced neurotoxicity.
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Affiliation(s)
- Faraz Ahmad
- School of Life Science, BS Abdur Rahman Crescent Institute of Science & Technology, Vandulur, Chennai 600048, India,
| | - Mohammad Salahuddin
- Animal House Department, Institute for Research and Medical Consultations, Imam Abdurrahman Bin Faisal University, Dammam 31441, Saudi Arabia
| | - Khaldoon Alsamman
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Imam Abdurrahman Bin Faisal University, Dammam 31441, Saudi Arabia
| | - Abdulaziz A AlMulla
- Department of Environmental Health, College of Public Health, Imam Abdurrahman Bin Faisal University, Dammam 31441, Saudi Arabia
| | - Khaled F Salama
- Department of Environmental Health, College of Public Health, Imam Abdurrahman Bin Faisal University, Dammam 31441, Saudi Arabia
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Ahmad F, Singh K, Das D, Gowaikar R, Shaw E, Ramachandran A, Rupanagudi KV, Kommaddi RP, Bennett DA, Ravindranath V. Reactive Oxygen Species-Mediated Loss of Synaptic Akt1 Signaling Leads to Deficient Activity-Dependent Protein Translation Early in Alzheimer's Disease. Antioxid Redox Signal 2017; 27:1269-1280. [PMID: 28264587 PMCID: PMC5655421 DOI: 10.1089/ars.2016.6860] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
AIMS Synaptic deficits are known to underlie the cognitive dysfunction seen in Alzheimer's disease (AD). Generation of reactive oxygen species (ROS) by β-amyloid has also been implicated in AD pathogenesis. However, it is unclear whether ROS contributes to synaptic dysfunction seen in AD pathogenesis and, therefore, we examined whether altered redox signaling could contribute to synaptic deficits in AD. RESULTS Activity dependent but not basal translation was impaired in synaptoneurosomes from 1-month old presymptomatic APPSwe/PS1ΔE9 (APP/PS1) mice, and this deficit was sustained till middle age (MA, 9-10 months). ROS generation leads to oxidative modification of Akt1 in the synapse and consequent reduction in Akt1-mechanistic target of rapamycin (mTOR) signaling, leading to deficiency in activity-dependent protein translation. Moreover, we found a similar loss of activity-dependent protein translation in synaptoneurosomes from postmortem AD brains. INNOVATION Loss of activity-dependent protein translation occurs presymptomatically early in the pathogenesis of AD. This is caused by ROS-mediated loss of pAkt1, leading to reduced synaptic Akt1-mTOR signaling and is rescued by overexpression of Akt1. ROS-mediated damage is restricted to the synaptosomes, indicating selectivity. CONCLUSIONS We demonstrate that ROS-mediated oxidative modification of Akt1 contributes to synaptic dysfunction in AD, seen as loss of activity-dependent protein translation that is essential for synaptic plasticity and maintenance. Therapeutic strategies promoting Akt1-mTOR signaling at synapses may provide novel target(s) for disease-modifying therapy in AD. Antioxid. Redox Signal. 27, 1269-1280.
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Affiliation(s)
- Faraz Ahmad
- 1 Centre for Neuroscience, Indian Institute of Science , Bangalore, India
| | - Kunal Singh
- 1 Centre for Neuroscience, Indian Institute of Science , Bangalore, India
| | - Debajyoti Das
- 1 Centre for Neuroscience, Indian Institute of Science , Bangalore, India
| | - Ruturaj Gowaikar
- 1 Centre for Neuroscience, Indian Institute of Science , Bangalore, India
| | - Eisha Shaw
- 1 Centre for Neuroscience, Indian Institute of Science , Bangalore, India
| | | | | | | | - David A Bennett
- 2 Rush Alzheimer's Disease Center, Rush University Medical Center , Chicago, Illinois
| | - Vijayalakshmi Ravindranath
- 1 Centre for Neuroscience, Indian Institute of Science , Bangalore, India .,3 Centre for Brain Research , Bangalore, India
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Krueger DA, Sadhwani A, Byars AW, de Vries PJ, Franz DN, Whittemore VH, Filip-Dhima R, Murray D, Kapur K, Sahin M. Everolimus for treatment of tuberous sclerosis complex-associated neuropsychiatric disorders. Ann Clin Transl Neurol 2017; 4:877-887. [PMID: 29296616 PMCID: PMC5740257 DOI: 10.1002/acn3.494] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 09/26/2017] [Accepted: 09/28/2017] [Indexed: 11/06/2022] Open
Abstract
Objective To evaluate if short-term treatment with everolimus was safe and could improve neurocognition and behavior in children with TSC. Methods This was a prospective, double-blind randomized, placebo-controlled two-center phase II study. Participants diagnosed with TSC and age 6-21 years were treated with 4.5 mg/m2 per day of oral everolimus (n = 32) or matching placebo (n = 15) taken once daily for 6 months. For efficacy, a comprehensive neurocognitive and behavioral evaluation battery was performed at baseline, 3 months, and 6 months. For safety, adverse events recorded continuously via patient diary were categorized and graded per NCI Common Toxicity Criteria for Adverse Events, version 3.0 (CTCAE 3.0). Analyses were performed on the intention-to-treat population (n = 47). Results Nearly all assessment measures failed to demonstrate significant differences between the two groups at the end of 6 months. Only one measure each of executive function (Cambridge Neuropsychological Test Automated Battery Stockings of Cambridge) favoring placebo (P = 0.025) and social cognition (Social Responsiveness Scale Social Cognition Subscale) favoring everolimus (P = 0.011) was observed. A total of 473 adverse events (AE) were reported. The average number of total AE per subject was similar for both placebo and everolimus. Most were mild or moderate in severity and serious AE were rare. Interpretation While safe, oral everolimus administered once daily for 6 months did not significantly improve neurocognitive functioning or behavior in children with TSC.
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Affiliation(s)
- Darcy A Krueger
- Division of Neurology Department of Pediatrics Cincinnati Children's Hospital Medical Center University of Cincinnati Cincinnati Ohio
| | - Anjali Sadhwani
- Department of Psychiatry Boston Children's Hospital and Harvard Medical School Boston Massachusetts
| | - Anna W Byars
- Division of Neurology Department of Pediatrics Cincinnati Children's Hospital Medical Center University of Cincinnati Cincinnati Ohio
| | - Petrus J de Vries
- Division of Child & Adolescent Psychiatry University of Cape Town Cape Town South Africa
| | - David N Franz
- Division of Neurology Department of Pediatrics Cincinnati Children's Hospital Medical Center University of Cincinnati Cincinnati Ohio
| | - Vicky H Whittemore
- National Institute of Neurological Disorders and Stroke National Institutes of Health Bethesda Maryland
| | - Rajna Filip-Dhima
- Department of Neurology Boston Children's Hospital Harvard Medical School Boston Massachusetts
| | - Donna Murray
- Autism Speaks Boston Massachusetts.,Division of Developmental & Behavioral Pediatrics Department of Pediatrics Cincinnati Children's Hospital Medical Center University of Cincinnati Cincinnati Ohio
| | - Kush Kapur
- Department of Neurology Boston Children's Hospital Harvard Medical School Boston Massachusetts
| | - Mustafa Sahin
- Department of Neurology Boston Children's Hospital Harvard Medical School Boston Massachusetts
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56
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Hou G, Zhang ZW. NMDA Receptors Regulate the Development of Neuronal Intrinsic Excitability through Cell-Autonomous Mechanisms. Front Cell Neurosci 2017; 11:353. [PMID: 29163060 PMCID: PMC5674002 DOI: 10.3389/fncel.2017.00353] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/24/2017] [Indexed: 01/30/2023] Open
Abstract
Maturation of neuronal and synaptic functions during early life is essential for the development of neuronal circuits and behaviors. In newborns synaptic transmission at excitatory synapses is primarily mediated by N-methyl-D-aspartate receptors (NMDARs), and NMDAR-mediated signaling plays an important role in synaptic maturation. Concomitant with synapse development, the intrinsic properties of neurons undergo dramatic changes during early life. However, little is known about the role of NMDARs in the development of intrinsic excitability. By using mosaic deletion of the obligatory GluN1 subunit of NMDARs in the thalamus of newborn mice, we showed that NMDARs regulate neuronal excitability during postnatal development. Compared with neighboring control neurons, neurons lacking NMDARs exhibit hyperexcitability and this effect is present throughout early life. Morphological analyses show that thalamic neurons without NMDARs have smaller soma size and fewer dendritic branches. Deletion of NMDARs causes a reduction of hyperpolarization-activated cation (HCN) channel function in thalamic neurons, and pharmacologically blocking HCN channels in wild type neurons mimics the effects of GluN1 deletion on intrinsic excitability. Deletion of GluN1 down-regulated mechanistic target of rapamycin (mTOR) signaling in thalamic neurons, and mosaic deletion of mTOR recapitulated the effects of GluN1 deletion. Our results demonstrate that NMDARs regulate intrinsic excitability and morphology of thalamic neurons through cell autonomous mechanisms that implicate mTOR signaling.
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Affiliation(s)
| | - Zhong-Wei Zhang
- The Jackson Laboratory for Mammalian Genetics, Bar Harbor, ME, United States
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57
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Levin N, Kritman M, Maroun M, Akirav I. Differential roles of the infralimbic and prelimbic areas of the prefrontal cortex in reconsolidation of a traumatic memory. Eur Neuropsychopharmacol 2017. [PMID: 28647452 DOI: 10.1016/j.euroneuro.2017.06.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Studies about reconsolidation of conditioned fear memories have shown that pharmacological manipulation at memory reactivation can attenuate or enhance the subsequent expression of the conditioned fear response. Here we examined the effects of a single injection of the mTOR inhibitor rapamycin (Rap) into the infralimbic (IL) and prelimbic (PL) areas [which compose the ventromedial prefrontal cortex (PFC)] on reconsolidation and extinction of a traumatic fear memory. We found opposite effects of Rap infused into the PL and IL on reconsolidation and extinction: intra-PL Rap and systemic Rap impaired reconsolidation and facilitated extinction whereas intra-IL Rap enhanced reconsolidation and impaired extinction. These effects persisted at least 10 days after reactivation. Shock exposure induced anxiety-like behavior and impaired working memory and intra-IL and -PL Rap normalized these effects. Finally, when measured after fear retrieval, shocked rats exhibited reduced and increased phosphorylated p70s6K levels in the IL and basolateral amygdala, respectively. No effect on phosphorylated p70s6K levels was observed in the PL. The study points to the differential roles of the IL and PL in memory reconsolidation and extinction. Moreover, inhibiting mTOR via rapamycin following reactivation of a fear memory may be a novel approach in attenuating enhanced fear memories.
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Affiliation(s)
- Natali Levin
- Department of Psychology, University of Haifa, Haifa 3498838, Israel
| | - Milly Kritman
- Sagol Department of Neurobiology, University of Haifa, Haifa 3498838, Israel
| | - Mouna Maroun
- Sagol Department of Neurobiology, University of Haifa, Haifa 3498838, Israel
| | - Irit Akirav
- Department of Psychology, University of Haifa, Haifa 3498838, Israel.
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Zanda MT, Fadda P, Antinori S, Di Chio M, Fratta W, Chiamulera C, Fattore L. Methoxetamine affects brain processing involved in emotional response in rats. Br J Pharmacol 2017; 174:3333-3345. [PMID: 28718892 DOI: 10.1111/bph.13952] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 06/30/2017] [Accepted: 07/06/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND PURPOSE Methoxetamine (MXE) is a novel psychoactive substance that is emerging on the Internet and induces dissociative effects and acute toxicity. Its pharmacological effects have not yet been adequately investigated. EXPERIMENTAL APPROACH We examined a range of behavioural effects induced by acute administration of MXE (0.5-5 mg·kg-1 ; i.p.) in rats and whether it causes rapid neuroadaptive molecular changes. KEY RESULTS MXE (0.5-5 mg·kg-1 ) affected motor activity in a dose- and time-dependent manner, inducing hypermotility and hypomotility at low and high doses respectively. At low and intermediate doses (0.5 and 1 mg·kg-1 ), MXE induced anxious and/or obsessive-compulsive traits (marble burying test), did not significantly increase sociability (social interaction test) or induce spatial anxiety (elevated plus maze test). At a high dose (5 mg·kg-1 ), MXE induced transient analgesia (tail-flick and hot-plate test), decreased social interaction time (social interaction test) and reduced immobility time while increasing swimming activity (forced swim test), suggesting an antidepressant effect. Acute MXE administration did not affect self-grooming behaviour at any dose tested. Immunohistochemical analysis showed that behaviourally active doses of MXE (1 and 5 mg·kg-1 ) increased phosphorylation of ribosomal protein S6 in the medial prefrontal cortex and hippocampus. CONCLUSIONS AND IMPLICATIONS MXE differentially affected motor activity, behaviour and emotional states in rats, depending on the dose tested. As reported for ketamine, phosphorylation of the ribosomal protein S6 was increased in MXE-treated animals, thus providing a 'molecular snapshot' of rapid neuroadaptive molecular changes induced by behaviourally active doses of MXE.
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Affiliation(s)
- M T Zanda
- Department of Biomedical Sciences, Division of Neuroscience and Clinical Pharmacology, University of Cagliari, Cagliari, Italy
| | - P Fadda
- Department of Biomedical Sciences, Division of Neuroscience and Clinical Pharmacology, University of Cagliari, Cagliari, Italy
| | - S Antinori
- Department of Biomedical Sciences, Division of Neuroscience and Clinical Pharmacology, University of Cagliari, Cagliari, Italy
| | - M Di Chio
- Department of Diagnostic and Public Health, Section of Pharmacology, University of Verona, Verona, Italy
| | - W Fratta
- Department of Biomedical Sciences, Division of Neuroscience and Clinical Pharmacology, University of Cagliari, Cagliari, Italy
| | - C Chiamulera
- Department of Diagnostic and Public Health, Section of Pharmacology, University of Verona, Verona, Italy
| | - L Fattore
- Institute of Neuroscience (IN-CNR), National Research Council of Italy, Cagliari, Italy
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Mcl-1 expression and JNK activation induces a threshold for apoptosis in Bcl-xL-overexpressing hematopoietic cells. Oncotarget 2017; 8:11042-11052. [PMID: 28038464 PMCID: PMC5355244 DOI: 10.18632/oncotarget.14223] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 12/20/2016] [Indexed: 02/05/2023] Open
Abstract
The regulation of Mcl-1 expression is necessary for the induction of cancer cell apoptosis by ABTs such as ABT-737, ABT-263 and ABT-199. However, the reduction in Mcl-1 expression is not sufficient for initiating cell death in hematopoietic cancer cells with high Bcl-xL expression. Here, we demonstrate that 2-deoxyglucose (2-DG) enhanced the effect of ABT-199 to induce cell apoptosis in hematologic malignancies with up-regulated Bcl-xL expression. Our study revealed that 2-DG could decrease glucose-dependent and Akt-independent Mcl-1 expression, which is mediated by the mechanistic target of rapamycin complex 1 (mTORC1) pathway. Moreover, the combination of 2-DG and ABT-199 triggered c-Jun NH2-terminal kinase (JNK) phosphorylation and subsequent Bcl-xL degradation, whereas 2-DG and ABT-199 alone had little effect on JNK activation. Therefore, the combination of 2-DG and ABT-199 initiated cell death through the reduction of Mcl-1 expression and JNK activation. Our study could provide a clinical theoretical basis for the use of ABT-199 in hematologic malignancies with excessive Bcl-xL expression.
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61
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Pirbhoy PS, Farris S, Steward O. Synaptically driven phosphorylation of ribosomal protein S6 is differentially regulated at active synapses versus dendrites and cell bodies by MAPK and PI3K/mTOR signaling pathways. ACTA ACUST UNITED AC 2017; 24:341-357. [PMID: 28716954 PMCID: PMC5516686 DOI: 10.1101/lm.044974.117] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 05/18/2017] [Indexed: 12/04/2022]
Abstract
High-frequency stimulation of the medial perforant path triggers robust phosphorylation of ribosomal protein S6 (rpS6) in activated dendritic domains and granule cell bodies. Here we dissect the signaling pathways responsible for synaptically driven rpS6 phosphorylation in the dentate gyrus using pharmacological agents to inhibit PI3-kinase/mTOR and MAPK/ERK-dependent kinases. Using phospho-specific antibodies for rpS6 at different sites (ser235/236 versus ser240/244), we show that delivery of the PI3-kinase inhibitor, wortmannin, decreased rpS6 phosphorylation throughout the somatodendritic compartment (granule cell layer, inner molecular layer, outer molecular layer), especially in granule cell bodies while sparing phosphorylation at activated synapses (middle molecular layer). In contrast, delivery of U0126, an MEK inhibitor, attenuated rpS6 phosphorylation specifically in the dendritic laminae leaving phosphorylation in the granule cell bodies intact. Delivery of the mTOR inhibitor, rapamycin, abolished activation of rpS6 phosphorylation in granule cell bodies and dendrites, whereas delivery of a selective S6K1 inhibitor, PF4708671, or RSK inhibitor, SL0101-1, attenuated rpS6 phosphorylation throughout the postsynaptic cell. These results reveal that MAPK/ERK-dependent signaling is predominately responsible for the selective induction of rpS6 phosphorylation at active synapses. In contrast, PI3-kinase/mTOR-dependent signaling induces rpS6 phosphorylation throughout the somatodendritic compartment but plays a minimal role at active synapses. Collectively, these results suggest a potential mechanism by which PI3-kinase/mTOR and MAPK/ERK pathways regulate translation at specific subcellular compartments in response to synaptic activity.
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Affiliation(s)
- Patricia Salgado Pirbhoy
- Reeve-Irvine Research Center, University of California, Irvine, California 92697, USA.,Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California, Irvine, California 92697, USA
| | - Shannon Farris
- Reeve-Irvine Research Center, University of California, Irvine, California 92697, USA.,Department of Anatomy and Neurobiology
| | - Oswald Steward
- Reeve-Irvine Research Center, University of California, Irvine, California 92697, USA.,Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, University of California, Irvine, California 92697, USA.,Department of Anatomy and Neurobiology.,Department of Neurosurgery, University of California, Irvine, California 92697, USA
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Niere F, Raab-Graham KF. mTORC1 Is a Local, Postsynaptic Voltage Sensor Regulated by Positive and Negative Feedback Pathways. Front Cell Neurosci 2017; 11:152. [PMID: 28611595 PMCID: PMC5447718 DOI: 10.3389/fncel.2017.00152] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/09/2017] [Indexed: 12/11/2022] Open
Abstract
The mammalian/mechanistic target of rapamycin complex 1 (mTORC1) serves as a regulator of mRNA translation. Recent studies suggest that mTORC1 may also serve as a local, voltage sensor in the postsynaptic region of neurons. Considering biochemical, bioinformatics and imaging data, we hypothesize that the activity state of mTORC1 dynamically regulates local membrane potential by promoting and repressing protein synthesis of select mRNAs. Our hypothesis suggests that mTORC1 uses positive and negative feedback pathways, in a branch-specific manner, to maintain neuronal excitability within an optimal range. In some dendritic branches, mTORC1 activity oscillates between the "On" and "Off" states. We define this as negative feedback. In contrast, positive feedback is defined as the pathway that leads to a prolonged depolarized or hyperpolarized resting membrane potential, whereby mTORC1 activity is constitutively on or off, respectively. We propose that inactivation of mTORC1 increases the expression of voltage-gated potassium alpha (Kv1.1 and 1.2) and beta (Kvβ2) subunits, ensuring that the membrane resets to its resting membrane potential after experiencing increased synaptic activity. In turn, reduced mTORC1 activity increases the protein expression of syntaxin-1A and promotes the surface expression of the ionotropic glutamate receptor N-methyl-D-aspartate (NMDA)-type subunit 1 (GluN1) that facilitates increased calcium entry to turn mTORC1 back on. Under conditions such as learning and memory, mTORC1 activity is required to be high for longer periods of time. Thus, the arm of the pathway that promotes syntaxin-1A and Kv1 protein synthesis will be repressed. Moreover, dendritic branches that have low mTORC1 activity with increased Kv expression would balance dendrites with constitutively high mTORC1 activity, allowing for the neuron to maintain its overall activity level within an ideal operating range. Finally, such a model suggests that recruitment of more positive feedback dendritic branches within a neuron is likely to lead to neurodegenerative disorders.
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Affiliation(s)
- Farr Niere
- Department of Physiology and Pharmacology, Wake Forest School of MedicineWinston-Salem, NC, United States
| | - Kimberly F. Raab-Graham
- Department of Physiology and Pharmacology, Wake Forest School of MedicineWinston-Salem, NC, United States
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Raab-Graham KF, Niere F. mTOR referees memory and disease through mRNA repression and competition. FEBS Lett 2017; 591:1540-1554. [PMID: 28493559 DOI: 10.1002/1873-3468.12675] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 05/04/2017] [Accepted: 05/05/2017] [Indexed: 12/11/2022]
Abstract
Mammalian target of rapamycin (mTOR) activity is required for memory and is dysregulated in disease. Activation of mTOR promotes protein synthesis; however, new studies are demonstrating that mTOR activity also represses the translation of mRNAs. Almost three decades ago, Kandel and colleagues hypothesised that memory was due to the induction of positive regulators and removal of negative constraints. Are these negative constraints repressed mRNAs that code for proteins that block memory formation? Herein, we will discuss the mRNAs coded by putative memory suppressors, how activation/inactivation of mTOR repress protein expression at the synapse, how mTOR activity regulates RNA binding proteins, mRNA stability, and translation, and what the possible implications of mRNA repression are to memory and neurodegenerative disorders.
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Affiliation(s)
- Kimberly F Raab-Graham
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston Salem, NC, USA
| | - Farr Niere
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston Salem, NC, USA
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Swiatkowski P, Nikolaeva I, Kumar G, Zucco A, Akum BF, Patel MV, D'Arcangelo G, Firestein BL. Role of Akt-independent mTORC1 and GSK3β signaling in sublethal NMDA-induced injury and the recovery of neuronal electrophysiology and survival. Sci Rep 2017; 7:1539. [PMID: 28484273 PMCID: PMC5431483 DOI: 10.1038/s41598-017-01826-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 04/03/2017] [Indexed: 01/02/2023] Open
Abstract
Glutamate-induced excitotoxicity, mediated by overstimulation of N-methyl-D-aspartate (NMDA) receptors, is a mechanism that causes secondary damage to neurons. The early phase of injury causes loss of dendritic spines and changes to synaptic activity. The phosphatidylinositol-4,5-bisphosphate 3-kinase/Akt/ mammalian target of rapamycin (PI3K/Akt/mTOR) pathway has been implicated in the modulation and regulation of synaptic strength, activity, maturation, and axonal regeneration. The present study focuses on the physiology and survival of neurons following manipulation of Akt and several downstream targets, such as GSK3β, FOXO1, and mTORC1, prior to NMDA-induced injury. Our analysis reveals that exposure to sublethal levels of NMDA does not alter phosphorylation of Akt, S6, and GSK3β at two and twenty four hours following injury. Electrophysiological recordings show that NMDA-induced injury causes a significant decrease in spontaneous excitatory postsynaptic currents at both two and twenty four hours, and this phenotype can be prevented by inhibiting mTORC1 or GSK3β, but not Akt. Additionally, inhibition of mTORC1 or GSK3β promotes neuronal survival following NMDA-induced injury. Thus, NMDA-induced excitotoxicity involves a mechanism that requires the permissive activity of mTORC1 and GSK3β, demonstrating the importance of these kinases in the neuronal response to injury.
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Affiliation(s)
- Przemyslaw Swiatkowski
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA.,Graduate Program in Molecular Biosciences, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA
| | - Ina Nikolaeva
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA.,Graduate Program in Molecular Biosciences, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA
| | - Gaurav Kumar
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA
| | - Avery Zucco
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA.,Graduate Program in Neurosciences, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA
| | - Barbara F Akum
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA
| | - Mihir V Patel
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA.,Graduate Program in Neurosciences, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA
| | - Gabriella D'Arcangelo
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA
| | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, New Jersey, 08854-8082, USA.
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Abstract
The primary processes that contribute to the efficient capture of soil nitrate are the development of a root system that effectively explores the soil and the expression of high-affinity nitrate uptake systems in those roots. Both these processes are highly regulated to take into account the availability and distribution of external nitrate pools and the endogenous N status of the plant. While significant progress has been made in elucidating the early steps in sensing and responding to external nitrate, there is much less clarity about how the plant monitors its N status. This review specifically addresses the questions of what N compounds are sensed and in which part of the plant, as well as the identity of the signalling pathways responsible for their detection. Candidates that are considered for the role of N sensory systems include the target of rapamycin (TOR) signalling pathway, the general control non-derepressible 2 (GCN2) pathway, the plastidic PII-dependent pathway, and the family of glutamate-like receptors (GLRs). However, despite significant recent progress in elucidating the function and mode of action of these signalling systems, there is still much uncertainty about the extent to which they contribute to the process by which plants monitor their N status. The possibility is discussed that the large GLR family of Ca2+ channels, which are gated by a wide range of different amino acids and expressed throughout the plant, could act as amino acid sensors upstream of a Ca2+-regulated signalling pathway, such as the TOR pathway, to regulate the plant's response to changes in N status.
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Affiliation(s)
- Lucas Gent
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - Brian G Forde
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
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Abelaira HM, Réus GZ, Ignácio ZM, Dos Santos MAB, de Moura AB, Matos D, Demo JP, da Silva JBI, Michels M, Abatti M, Sonai B, Dal Pizzol F, Carvalho AF, Quevedo J. Effects of ketamine administration on mTOR and reticulum stress signaling pathways in the brain after the infusion of rapamycin into prefrontal cortex. J Psychiatr Res 2017; 87:81-87. [PMID: 28017918 DOI: 10.1016/j.jpsychires.2016.12.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 10/13/2016] [Accepted: 12/01/2016] [Indexed: 12/23/2022]
Abstract
Recent studies show that activation of the mTOR signaling pathway is required for the rapid antidepressant actions of glutamate N-methyl-D-aspartate (NMDA) receptor antagonists. A relationship between mTOR kinase and the endoplasmic reticulum (ER) stress pathway, also known as the unfolded protein response (UPR) has been shown. We evaluate the effects of ketamine administration on the mTOR signaling pathway and proteins of UPR in the prefrontal cortex (PFC), hippocampus, amygdala and nucleus accumbens, after the inhibiton of mTOR signaling in the PFC. Male adult Wistar rats received pharmacological mTOR inhibitor, rapamycin (0.2 nmol), or vehicle into the PFC and then a single dose of ketamine (15 mg/kg, i.p.). The immunocontent of mTOR, eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), eukaryotic elongation factor 2 kinase (eEF2K) homologous protein (CHOP), PKR-like ER kinase (PERK) and inositol-requiring enzyme 1 (IRE1) - alpha were determined in the brain. The mTOR levels were reduced in the rapamycin group treated with saline and ketamine in the PFC; p4EBP1 levels were reduced in the rapamycin group treated with ketamine in the PFC and nucleus accumbens; the levels of peEF2K were increased in the PFC in the vehicle group treated with ketamine and reduced in the rapamycin group treated with ketamine. The PERK and IRE1-alpha levels were decreased in the PFC in the rapamycin group treated with ketamine. Our results suggest that mTOR signaling inhibition by rapamycin could be involved, at least in part, with the mechanism of action of ketamine; and the ketamine antidepressant on ER stress pathway could be also mediated by mTOR signaling pathway in certain brain structures.
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Affiliation(s)
- Helena M Abelaira
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Gislaine Z Réus
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil.
| | - Zuleide M Ignácio
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Maria Augusta B Dos Santos
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Airam B de Moura
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Danyela Matos
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Júlia P Demo
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Júlia B I da Silva
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Monique Michels
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Mariane Abatti
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Beatriz Sonai
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Felipe Dal Pizzol
- Laboratório de Fisiopatologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - André F Carvalho
- Translational Psychiatry Research Group and Department of Clinical Medicine, Faculty of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil
| | - João Quevedo
- Laboratório de Neurociências, Programa de Pós-Graduação em Ciências da Saúde, Unidade Acadêmica de Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil; Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA; Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA; Neuroscience Graduate Program, The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, USA
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67
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Switon K, Kotulska K, Janusz-Kaminska A, Zmorzynska J, Jaworski J. Molecular neurobiology of mTOR. Neuroscience 2017; 341:112-153. [PMID: 27889578 DOI: 10.1016/j.neuroscience.2016.11.017] [Citation(s) in RCA: 277] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 11/09/2016] [Accepted: 11/13/2016] [Indexed: 01/17/2023]
Abstract
Mammalian/mechanistic target of rapamycin (mTOR) is a serine-threonine kinase that controls several important aspects of mammalian cell function. mTOR activity is modulated by various intra- and extracellular factors; in turn, mTOR changes rates of translation, transcription, protein degradation, cell signaling, metabolism, and cytoskeleton dynamics. mTOR has been repeatedly shown to participate in neuronal development and the proper functioning of mature neurons. Changes in mTOR activity are often observed in nervous system diseases, including genetic diseases (e.g., tuberous sclerosis complex, Pten-related syndromes, neurofibromatosis, and Fragile X syndrome), epilepsy, brain tumors, and neurodegenerative disorders (Alzheimer's disease, Parkinson's disease, and Huntington's disease). Neuroscientists only recently began deciphering the molecular processes that are downstream of mTOR that participate in proper function of the nervous system. As a result, we are gaining knowledge about the ways in which aberrant changes in mTOR activity lead to various nervous system diseases. In this review, we provide a comprehensive view of mTOR in the nervous system, with a special focus on the neuronal functions of mTOR (e.g., control of translation, transcription, and autophagy) that likely underlie the contribution of mTOR to nervous system diseases.
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Affiliation(s)
- Katarzyna Switon
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena Street, Warsaw 02-109, Poland
| | - Katarzyna Kotulska
- Department of Neurology and Epileptology, Children's Memorial Health Institute, Aleja Dzieci Polskich 20, Warsaw 04-730, Poland
| | | | - Justyna Zmorzynska
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena Street, Warsaw 02-109, Poland
| | - Jacek Jaworski
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena Street, Warsaw 02-109, Poland.
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68
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Mostaid MS, Lee TT, Chana G, Sundram S, Shannon Weickert C, Pantelis C, Everall I, Bousman C. Peripheral Transcription of NRG-ErbB Pathway Genes Are Upregulated in Treatment-Resistant Schizophrenia. Front Psychiatry 2017; 8:225. [PMID: 29163244 PMCID: PMC5681734 DOI: 10.3389/fpsyt.2017.00225] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 10/23/2017] [Indexed: 12/13/2022] Open
Abstract
Investigation of peripheral gene expression patterns of transcripts within the NRG-ErbB signaling pathway, other than neuregulin-1 (NRG1), among patients with schizophrenia and more specifically treatment-resistant schizophrenia (TRS) is limited. The present study built on our previous work demonstrating elevated levels of NRG1 EGFα, EGFβ, and type I(Ig2) containing transcripts in TRS by investigating 11 NRG-ErbB signaling pathway mRNA transcripts (NRG2, ErbB1, ErbB2, ErbB3, ErbB4, PIK3CD, PIK3R3, AKT1, mTOR, P70S6K, eIF4EBP1) in whole blood of TRS patients (N = 71) and healthy controls (N = 57). We also examined the effect of clozapine exposure on transcript levels using cultured peripheral blood mononuclear cells (PBMCs) from 15 healthy individuals. Five transcripts (ErbB3, PIK3CD, AKT1, P70S6K, eIF4EBP1) were significantly elevated in TRS patients compared to healthy controls but only expression of P70S6K (Pcorrected = 0.018), a protein kinase linked to protein synthesis, cell growth, and cell proliferation, survived correction for multiple testing using the Benjamini-Hochberg method. Investigation of clinical factors revealed that ErbB2, PIK3CD, PIK3R3, AKT1, mTOR, and P70S6K expression were negatively correlated with duration of illness. However, no transcript was associated with chlorpromazine equivalent dose or clozapine plasma levels, the latter supported by our in vitro PBMC clozapine exposure experiment. Taken together with previously published NRG1 results, our findings suggest an overall upregulation of transcripts within the NRG-ErbB signaling pathway among individuals with schizophrenia some of which attenuate over duration of illness. Follow-up studies are needed to determine if the observed peripheral upregulation of transcripts within the NRG-ErbB signaling pathway are specific to TRS or are a general blood-based marker of schizophrenia.
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Affiliation(s)
- Md Shaki Mostaid
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Parkville, VIC, Australia.,The Cooperative Research Centre (CRC) for Mental Health, Melbourne, VIC, Australia
| | - Ting Ting Lee
- Centre for Neural Engineering, The University of Melbourne, Carlton, VIC, Australia
| | - Gursharan Chana
- Centre for Neural Engineering, The University of Melbourne, Carlton, VIC, Australia.,Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.,Department of Medicine, Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Suresh Sundram
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.,NorthWestern Mental Health, Melbourne, VIC, Australia.,Department of Psychiatry, School of Clinical Sciences, Monash University and Monash Health, Clayton, VIC, Australia
| | - Cynthia Shannon Weickert
- Schizophrenia Research Institute, Sydney, NSW, Australia.,Schizophrenia Research Laboratory, Neuroscience Research Australia, Sydney, NSW, Australia.,Faculty of Medicine, School of Psychiatry, University of New South Wales, Sydney, NSW, Australia
| | - Christos Pantelis
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Parkville, VIC, Australia.,The Cooperative Research Centre (CRC) for Mental Health, Melbourne, VIC, Australia.,Centre for Neural Engineering, The University of Melbourne, Carlton, VIC, Australia.,Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.,NorthWestern Mental Health, Melbourne, VIC, Australia
| | - Ian Everall
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Parkville, VIC, Australia.,The Cooperative Research Centre (CRC) for Mental Health, Melbourne, VIC, Australia.,Centre for Neural Engineering, The University of Melbourne, Carlton, VIC, Australia.,Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.,NorthWestern Mental Health, Melbourne, VIC, Australia.,Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Chad Bousman
- Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Parkville, VIC, Australia.,The Cooperative Research Centre (CRC) for Mental Health, Melbourne, VIC, Australia.,Department of Medical Genetics, University of Calgary, Calgary, AB, Canada.,Department of Psychiatry, University of Calgary, Calgary, AB, Canada.,Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
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69
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Daroles L, Gribaudo S, Doulazmi M, Scotto-Lomassese S, Dubacq C, Mandairon N, Greer CA, Didier A, Trembleau A, Caillé I. Fragile X Mental Retardation Protein and Dendritic Local Translation of the Alpha Subunit of the Calcium/Calmodulin-Dependent Kinase II Messenger RNA Are Required for the Structural Plasticity Underlying Olfactory Learning. Biol Psychiatry 2016; 80:149-159. [PMID: 26372002 DOI: 10.1016/j.biopsych.2015.07.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 07/16/2015] [Accepted: 07/22/2015] [Indexed: 12/12/2022]
Abstract
BACKGROUND In the adult brain, structural plasticity allowing gain or loss of synapses remodels circuits to support learning. In fragile X syndrome, the absence of fragile X mental retardation protein (FMRP) leads to defects in plasticity and learning deficits. FMRP is a master regulator of local translation but its implication in learning-induced structural plasticity is unknown. METHODS Using an olfactory learning task requiring adult-born olfactory bulb neurons and cell-specific ablation of FMRP, we investigated whether learning shapes adult-born neuron morphology during their synaptic integration and its dependence on FMRP. We used alpha subunit of the calcium/calmodulin-dependent kinase II (αCaMKII) mutant mice with altered dendritic localization of αCaMKII messenger RNA, as well as a reporter of αCaMKII local translation to investigate the role of this FMRP messenger RNA target in learning-dependent structural plasticity. RESULTS Learning induces profound changes in dendritic architecture and spine morphology of adult-born neurons that are prevented by ablation of FMRP in adult-born neurons and rescued by an metabotropic glutamate receptor 5 antagonist. Moreover, dendritically translated αCaMKII is necessary for learning and associated structural modifications and learning triggers an FMRP-dependent increase of αCaMKII dendritic translation in adult-born neurons. CONCLUSIONS Our results strongly suggest that FMRP mediates structural plasticity of olfactory bulb adult-born neurons to support olfactory learning through αCaMKII local translation. This reveals a new role for FMRP-regulated dendritic local translation in learning-induced structural plasticity. This might be of clinical relevance for the understanding of critical periods disruption in autism spectrum disorder patients, among which fragile X syndrome is the primary monogenic cause.
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Affiliation(s)
- Laura Daroles
- Sorbonne Universités, Université Pierre et Marie Curie Univ Paris 06, Centre National de la Recherche Scientifique UMR8246, INSERM U1130, IBPS, Neuroscience Paris Seine, France
| | - Simona Gribaudo
- Sorbonne Universités, Université Pierre et Marie Curie Univ Paris 06, Centre National de la Recherche Scientifique UMR8246, INSERM U1130, IBPS, Neuroscience Paris Seine, France
| | - Mohamed Doulazmi
- Sorbonne Universités, Université Pierre et Marie Curie Univ Paris 06, Centre National de la Recherche Scientifique UMR8246, INSERM U1130, IBPS, Neuroscience Paris Seine, France
| | - Sophie Scotto-Lomassese
- Sorbonne Universités, Université Pierre et Marie Curie Univ Paris 06, Centre National de la Recherche Scientifique UMR8246, INSERM U1130, IBPS, Neuroscience Paris Seine, France
| | - Caroline Dubacq
- Sorbonne Universités, Université Pierre et Marie Curie Univ Paris 06, Centre National de la Recherche Scientifique UMR8246, INSERM U1130, IBPS, Neuroscience Paris Seine, France
| | - Nathalie Mandairon
- Université Lyon1, CNRS UMR 5292, INSERM U1028, Centre de Recherche en Neurosciences de Lyon
| | - Charles August Greer
- Yale University School of Medicine, Department of Neurosurgery, New Haven, Connecticut
| | - Anne Didier
- Université Lyon1, CNRS UMR 5292, INSERM U1028, Centre de Recherche en Neurosciences de Lyon
| | - Alain Trembleau
- Sorbonne Universités, Université Pierre et Marie Curie Univ Paris 06, Centre National de la Recherche Scientifique UMR8246, INSERM U1130, IBPS, Neuroscience Paris Seine, France
| | - Isabelle Caillé
- Sorbonne Universités, Université Pierre et Marie Curie Univ Paris 06, Centre National de la Recherche Scientifique UMR8246, INSERM U1130, IBPS, Neuroscience Paris Seine, France; Sorbonne Paris Cité, Université Paris Diderot-Paris 7.
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70
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Zhuang F, Li M, Gao X, Wang Y, Wang D, Ma X, Ma T, Gu S. The antidepressant-like effect of alarin is related to TrkB-mTOR signaling and synaptic plasticity. Behav Brain Res 2016; 313:158-171. [PMID: 27374162 DOI: 10.1016/j.bbr.2016.06.057] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 06/27/2016] [Accepted: 06/29/2016] [Indexed: 12/22/2022]
Abstract
Alarin is a newly derived neuropeptide from a splice variant of the galanin-like peptide gene. We previously showed that alarin has an antidepressant-like effect by increasing the activity of the extracellular signal-regulated kinase (ERK) and protein kinase B (AKT) pathways, mediated by the tropomyosin-related kinase B receptor in the unpredictable chronic mild stress (UCMS) mouse model. Administration of rapamycin, a mammalian target of rapamycin (mTOR) inhibitor, prevents the rapid antidepressant-like effect induced by ketamine in animal models, indicating a vital role of mTOR in depression pathophysiology. mTOR is a target of the ERK and AKT pathways that regulates the initiation of protein translation via its downstream components: ribosomal protein S6 kinase (p70S6K) and eukaryotic initiation factor 4E binding protein 1 (4E-BP1). Therefore, we hypothesized that the antidepressant-like effects of alarin were achieved by activating ERK/AKT pathways, increasing the activity of mTOR and its downstream signaling components that contribute to protein synthesis required for synaptic plasticity. Our results suggest that intracerebroventricular administration of alarin significantly ameliorates depression-like behaviors in the UCMS mouse model. Furthermore, alarin restored UCMS-induced reductions of p70S6K and post-synaptic density 95 (PSD-95) mRNA levels, and of phospho-mTOR and phospho-4EBP1 in the prefrontal cortex, hippocampus, hypothalamus, and olfactory bulb. Additionally, alarin reversed the UCMS-induced downregulation of PSD-95 and synapsin I protein expression in these brain regions. Thus, the antidepressant-like effects of alarin may be mediated by restoring decreased activity of the mTOR signaling pathway and expression of synaptic proteins. Our findings help advance the understanding of depression pathophysiology.
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Affiliation(s)
- Fuzhi Zhuang
- Department of Pharmacy, The First People's Hospital of Wujiang, Suzhou 215200, China
| | - Mei Li
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Department of Pharmacology, Xuzhou Medical University, Xuzhou 221004, China
| | - Xin Gao
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Department of Pharmacology, Xuzhou Medical University, Xuzhou 221004, China
| | - Yun Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Department of Pharmacology, Xuzhou Medical University, Xuzhou 221004, China
| | - Dongdong Wang
- Department of Pharmacy, The People's Hospital of Jiangyin, Wuxi 214400, China
| | - Xing Ma
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Department of Pharmacology, Xuzhou Medical University, Xuzhou 221004, China
| | - Tengfei Ma
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Department of Pharmacology, Xuzhou Medical University, Xuzhou 221004, China
| | - Shuling Gu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Department of Pharmacology, Xuzhou Medical University, Xuzhou 221004, China.
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Luo YX, Han H, Shao J, Gao Y, Yin X, Zhu WL, Han Y, Shi HS. mTOR signalling in the nucleus accumbens shell is critical for augmented effect of TFF3 on behavioural response to cocaine. Sci Rep 2016; 6:27895. [PMID: 27282818 PMCID: PMC4901260 DOI: 10.1038/srep27895] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 05/26/2016] [Indexed: 12/25/2022] Open
Abstract
Neuropeptides play important roles in modulating the rewarding value of abused drugs. Trefoil factor 3 (TFF3) was recently reported to modulate withdrawal syndrome of morphine, but the effects of TFF3 on the cocaine-induced behavioral changes are still elusive. In the present study, cocaine-induced hyperlocomotion and conditioned place preference (CPP) rat paradigms were provided to investigate the role of TFF3 in the reward response to cocaine. High-performance liquid chromatography (HPLC) analysis was used to analyse the dopamine concentration. The results showed that systemic TFF3 administration (0.1 mg/kg i.p.) significantly augmented cocaine- induced hyperlocomotion and CPP formation, without any effects on locomotor activity and aversive or rewarding effects per se. TFF3 significantly augmented the increment of the dopamine concentration in the NAc and the activity of the mTOR signalling pathway induced by acute cocaine exposure (10 mg/kg, i.p.) in the NAc shell, but not the core. The Intra-NAc shell infusion of rapamycin blocked TFF3-induced hyperactivity in cocaine-treatment rats. These findings indicated that TFF3 could potentiate behavioural response to cocaine, which may be associated with regulating dopamine concentration. Furthermore, the findings indicated that mTOR signalling pathway in the NAc shell is important for TFF3-induced enhancement on the cocaine-induced behavioral changes.
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Affiliation(s)
- Yi-Xiao Luo
- Department of Pharmacology, Medical School of Hunan Normal University, Changsha 410013, China
| | - Hua Han
- Department of gynecology and obstetrics, Hebei General Hospital, Shijiazhuang 050051, China
| | - Juan Shao
- Department of Senile Disease, the Third Hospital of Hebei Medical University, Shijiazhuang 050000, China
| | - Yuan Gao
- Department of Biochemistry and Molecular Biology, College of basic medicine, Hebei Medical University, Shijiazhuang 050017, China
| | - Xi Yin
- Department of Functional region of Diagnosis, Hebei Medical University Fourth Hospital, Hebei Medical University, Shijiazhuang 050011, China
| | - Wei-Li Zhu
- National Institute on Drug Dependence, Peking University, Beijing 100191, China
| | - Ying Han
- National Institute on Drug Dependence, Peking University, Beijing 100191, China
| | - Hai-Shui Shi
- Department of Biochemistry and Molecular Biology, College of basic medicine, Hebei Medical University, Shijiazhuang 050017, China.,National Institute on Drug Dependence, Peking University, Beijing 100191, China
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72
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Ruegsegger C, Stucki DM, Steiner S, Angliker N, Radecke J, Keller E, Zuber B, Rüegg MA, Saxena S. Impaired mTORC1-Dependent Expression of Homer-3 Influences SCA1 Pathophysiology. Neuron 2016; 89:129-46. [PMID: 26748090 DOI: 10.1016/j.neuron.2015.11.033] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 10/06/2015] [Accepted: 11/17/2015] [Indexed: 11/25/2022]
Abstract
Spinocerebellar ataxia type 1 (SCA1), due to the expansion of a polyglutamine repeat within the ubiquitously expressed Ataxin-1 protein, leads to the premature degeneration of Purkinje cells (PCs), the cause of which is poorly understood. Here, we identified the unique proteomic signature of Sca1(154Q/2Q) PCs at an early stage of disease, highlighting extensive alterations in proteins associated with synaptic functioning, maintenance, and transmission. Focusing on Homer-3, a PC-enriched scaffold protein regulating neuronal activity, revealed an early decline in its expression. Impaired climbing fiber-mediated synaptic transmission diminished mTORC1 signaling, paralleling Homer-3 reduction in Sca1(154Q/2Q) PCs. Ablating mTORC1 within PCs or pharmacological inhibition of mTORC1 identified Homer-3 as its downstream target. mTORC1 knockout in Sca1(154Q/2Q) PCs exacerbated and accelerated pathology. Reinstating Homer-3 expression in Sca1(154Q/2Q) PCs attenuated cellular dysfunctions and improved motor deficits. Our work reveals that impaired mTORC1-Homer-3 activity underlies PC susceptibility in SCA1 and presents a promising therapeutic target.
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Affiliation(s)
- Céline Ruegsegger
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012 Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, CH-3012 Bern, Switzerland
| | - David M Stucki
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012 Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, CH-3012 Bern, Switzerland
| | - Silvio Steiner
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012 Bern, Switzerland
| | - Nico Angliker
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
| | - Julika Radecke
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH-3012 Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, CH-3012 Bern, Switzerland
| | - Eva Keller
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012 Bern, Switzerland
| | - Benoît Zuber
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH-3012 Bern, Switzerland
| | - Markus A Rüegg
- Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
| | - Smita Saxena
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012 Bern, Switzerland.
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Spencer KB, Mulholland PJ, Chandler LJ. FMRP Mediates Chronic Ethanol-Induced Changes in NMDA, Kv4.2, and KChIP3 Expression in the Hippocampus. Alcohol Clin Exp Res 2016; 40:1251-61. [PMID: 27147118 DOI: 10.1111/acer.13060] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/04/2016] [Indexed: 11/30/2022]
Abstract
BACKGROUND Exposure to chronic ethanol (EtOH) results in changes in the expression of proteins that regulate neuronal excitability. This study examined whether chronic EtOH alters the hippocampal expression and function of fragile X mental retardation protein (FMRP) and the role of FMRP in the modulation of chronic EtOH-induced changes in the expression of NMDA receptors and Kv4.2 channels. METHODS For in vivo studies, C57BL/6J mice underwent a chronic intermittent EtOH (CIE) vapor exposure procedure. After CIE, hippocampal tissue was collected and subjected to immunoblot blot analysis of NMDA receptor subunits (GluN1, GluN2B), Kv4.2, and its accessory protein KChIP3. For in vitro studies, hippocampal slice cultures were exposed to 75 mM EtOH for 8 days. Following EtOH exposure, mRNAs bound to FMRP was measured. In a separate set of studies, cultures were exposed to an inhibitor of S6K1 (PF-4708671 [PF], 6 μM) in order to assess whether EtOH-induced homeostatic changes in protein expression depend upon changes in FMRP activity. RESULTS Immunoblot blot analysis revealed increases in GluN1 and GluN2B but reductions in Kv4.2 and KChIP3. Analysis of mRNAs bound to FMRP revealed a similar bidirectional change observed as reduction of GluN2B and increase in Kv4.2 and KChIP3 mRNA transcripts. Analysis of FMRP further revealed that while chronic EtOH did not alter the expression of FMRP, it significantly increased phosphorylation of FMRP at the S499 residue that is known to critically regulate its activity. Inhibition of S6K1 prevented the chronic EtOH-induced increase in phospho-FMRP and changes in NMDA subunits, Kv4.2, and KChIP3. In contrast, PF had no effect in the absence of alcohol, indicating it was specific for the chronic EtOH-induced changes. CONCLUSIONS These findings demonstrate that chronic EtOH exposure enhances translational control of plasticity-related proteins by FMRP, and that S6K1 and FMRP activities are required for expression of chronic EtOH-induced homeostatic plasticity at glutamatergic synapses in the hippocampus.
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Affiliation(s)
- Kathryn B Spencer
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina
| | - Patrick J Mulholland
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina
| | - L Judson Chandler
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina
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74
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Maiese K. Targeting molecules to medicine with mTOR, autophagy and neurodegenerative disorders. Br J Clin Pharmacol 2015; 82:1245-1266. [PMID: 26469771 DOI: 10.1111/bcp.12804] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Revised: 10/11/2015] [Accepted: 10/13/2015] [Indexed: 12/14/2022] Open
Abstract
Neurodegenerative disorders are significantly increasing in incidence as the age of the global population continues to climb with improved life expectancy. At present, more than 30 million individuals throughout the world are impacted by acute and chronic neurodegenerative disorders with limited treatment strategies. The mechanistic target of rapamycin (mTOR), also known as the mammalian target of rapamycin, is a 289 kDa serine/threonine protein kinase that offers exciting possibilities for novel treatment strategies for a host of neurodegenerative diseases that include Alzheimer's disease, Parkinson's disease, Huntington's disease, epilepsy, stroke and trauma. mTOR governs the programmed cell death pathways of apoptosis and autophagy that can determine neuronal stem cell development, precursor cell differentiation, cell senescence, cell survival and ultimate cell fate. Coupled to the cellular biology of mTOR are a number of considerations for the development of novel treatments involving the fine control of mTOR signalling, tumourigenesis, complexity of the apoptosis and autophagy relationship, functional outcome in the nervous system, and the intimately linked pathways of growth factors, phosphoinositide 3-kinase (PI 3-K), protein kinase B (Akt), AMP activated protein kinase (AMPK), silent mating type information regulation two homologue one (Saccharomyces cerevisiae) (SIRT1) and others. Effective clinical translation of the cellular signalling mechanisms of mTOR offers provocative avenues for new drug development in the nervous system tempered only by the need to elucidate further the intricacies of the mTOR pathway.
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Affiliation(s)
- Kenneth Maiese
- Cellular and Molecular Signaling, Newark, New Jersey, 07101, USA.
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75
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Chaudhury D, Liu H, Han MH. Neuronal correlates of depression. Cell Mol Life Sci 2015; 72:4825-48. [PMID: 26542802 PMCID: PMC4709015 DOI: 10.1007/s00018-015-2044-6] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Revised: 08/27/2015] [Accepted: 09/10/2015] [Indexed: 12/14/2022]
Abstract
Major depressive disorder (MDD) is a common psychiatric disorder effecting approximately 121 million people worldwide and recent reports from the World Health Organization (WHO) suggest that it will be the leading contributor to the global burden of diseases. At present, the most commonly used treatment strategies are still based on the monoamine hypothesis that has been the predominant theory in the last 60 years. Clinical observations show that only a subset of depressed patients exhibits full remission when treated with classical monoamine-based antidepressants together with the fact that patients exhibit multiple symptoms suggest that the pathophysiology leading to mood disorders may differ between patients. Accumulating evidence indicates that depression is a neural circuit disorder and that onset of depression may be located at different regions of the brain involving different transmitter systems and molecular mechanisms. This review synthesises findings from rodent studies from which emerges a role for different, yet interconnected, molecular systems and associated neural circuits to the aetiology of depression.
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Affiliation(s)
- Dipesh Chaudhury
- Division of Science, Experimental Research Building, Office 106, New York University Abu Dhabi (NYUAD), Saadiyat Island Campus, P.O. Box 129188, Abu Dhabi, United Arab Emirates.
| | - He Liu
- Division of Science, Experimental Research Building, Office 106, New York University Abu Dhabi (NYUAD), Saadiyat Island Campus, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Ming-Hu Han
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
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Abstract
INTRODUCTION Angelman syndrome (AS) is a neurodevelopmental disorder caused by deficiency of maternally inherited UBE3A, an ubiquitin E3 ligase. Despite recent progress in understanding the mechanism underlying UBE3A imprinting, there is no effective treatment. Further investigation of the roles played by UBE3A in the central nervous system (CNS) is needed for developing effective therapies. AREA COVERED This review covers the literature related to genetic classifications of AS, recent discoveries regarding the regulation of UBE3A imprinting, alterations in cell signaling in various brain regions and potential therapeutic approaches. Since a large proportion of AS patients exhibit comorbid autism spectrum disorder (ASD), potential common molecular bases are discussed. EXPERT OPINION Advances in understanding UBE3A imprinting provide a unique opportunity to induce paternal UBE3A expression, thus targeting the syndrome at its 'root.' However, such efforts have yielded less-than-expected rescue effects in AS mouse models, raising the concern that activation of paternal UBE3A after a critical period cannot correct all the CNS defects that developed in a UBE3A-deficient environment. On the other hand, targeting abnormal downstream cell signaling pathways has provided promising rescue effects in preclinical research. Thus, combined reinstatement of paternal UBE3A expression with targeting abnormal signaling pathways should provide better therapeutic effects.
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Affiliation(s)
- Xiaoning Bi
- a Department of Basic Medical Sciences, COMP , Western University of Health Sciences , Pomona , CA , USA
| | - Jiandong Sun
- a Department of Basic Medical Sciences, COMP , Western University of Health Sciences , Pomona , CA , USA
| | - Angela X Ji
- a Department of Basic Medical Sciences, COMP , Western University of Health Sciences , Pomona , CA , USA
| | - Michel Baudry
- b Graduate College of Biomedical Sciences , Western University of Health Sciences , Pomona , CA , USA
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Liu XL, Luo L, Mu RH, Liu BB, Geng D, Liu Q, Yi LT. Fluoxetine regulates mTOR signalling in a region-dependent manner in depression-like mice. Sci Rep 2015; 5:16024. [PMID: 26522512 PMCID: PMC4629199 DOI: 10.1038/srep16024] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 10/08/2015] [Indexed: 01/21/2023] Open
Abstract
Previous studies have demonstrated that the mammalian target of rapamycin (mTOR) signaling pathway has an important role in ketamine-induced, rapid antidepressant effects despite the acute administration of fluoxetine not affecting mTOR phosphorylation in the brain. However, the effects of long-term fluoxetine treatment on mTOR modulation have not been assessed to date. In the present study, we examined whether fluoxetine, a type of commonly used antidepressant agent, alters mTOR signaling following chronic administration in different brain regions, including the frontal cortex, hippocampus, amygdala and hypothalamus. We also investigated whether fluoxetine enhanced synaptic protein levels in these regions via the activation of the mTOR signaling pathway and its downstream regulators, p70S6K and 4E-BP-1. The results indicated that chronic fluoxetine treatment attenuated the chronic, unpredictable, mild stress (CUMS)-induced mTOR phosphorylation reduction in the hippocampus and amygdala of mice but not in the frontal cortex or the hypothalamus. Moreover, the CUMS-decreased PSD-95 and synapsin I levels were reversed by fluoxetine, and these effects were blocked by rapamycin only in the hippocampus. In conclusion, our findings suggest that chronic treatment with fluoxetine can induce synaptic protein expression by activating the mTOR signaling pathway in a region-dependent manner and mainly in the hippocampus.
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Affiliation(s)
- Xiao-Long Liu
- Department of Chemical and Pharmaceutical Engineering, College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian province, PR China
| | - Liu Luo
- Department of Chemical and Pharmaceutical Engineering, College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian province, PR China
| | - Rong-Hao Mu
- Department of Chemical and Pharmaceutical Engineering, College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian province, PR China
| | - Bin-Bin Liu
- Department of Chemical and Pharmaceutical Engineering, College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian province, PR China
| | - Di Geng
- Department of Chemical and Pharmaceutical Engineering, College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian province, PR China
| | - Qing Liu
- Department of Chemical and Pharmaceutical Engineering, College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian province, PR China
| | - Li-Tao Yi
- Department of Chemical and Pharmaceutical Engineering, College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian province, PR China
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Hussain S, Bashir ZI. The epitranscriptome in modulating spatiotemporal RNA translation in neuronal post-synaptic function. Front Cell Neurosci 2015; 9:420. [PMID: 26582006 PMCID: PMC4628113 DOI: 10.3389/fncel.2015.00420] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 10/04/2015] [Indexed: 01/08/2023] Open
Abstract
The application of next-generation-sequencing based methods has recently allowed the sequence-specific occurrence of RNA modifications to be investigated in transcriptome-wide settings. This has led to the emergence of a new field of molecular genetics research termed “epitranscriptomics.” Investigations have shown that these modifications can exert control over protein synthesis via various mechanisms, and particularly when occurring on messenger RNAs, can be dynamically regulated. Here, we propose that RNA modifications may be a critical regulator over the spatiotemporal control of protein-synthesis in neurons, which is supported by our finding that the RNA methylase NSun2 colocalizes with the translational-repressor FMRP at neuronal dendrites. We also observe that NSun2 commonly methylates mRNAs which encode components of the postsynaptic proteome, and further find that NSun2 and FMRP likely share a common subset of mRNA targets which include those that are known to be translated at dendrites in an activity-dependent manner. We consider potential roles for RNA modifications in space- time- and activity-dependent regulation of protein synthesis in neuronal physiology, with a particular focus on synaptic plasticity modulation.
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Affiliation(s)
- Shobbir Hussain
- Department of Biology and Biochemistry, University of Bath Bath, UK
| | - Zafar I Bashir
- School of Physiology and Pharmacology, University of Bristol Bristol, UK
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79
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Niere F, Namjoshi S, Song E, Dilly GA, Schoenhard G, Zemelman BV, Mechref Y, Raab-Graham KF. Analysis of Proteins That Rapidly Change Upon Mechanistic/Mammalian Target of Rapamycin Complex 1 (mTORC1) Repression Identifies Parkinson Protein 7 (PARK7) as a Novel Protein Aberrantly Expressed in Tuberous Sclerosis Complex (TSC). Mol Cell Proteomics 2015; 15:426-44. [PMID: 26419955 DOI: 10.1074/mcp.m115.055079] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Indexed: 01/05/2023] Open
Abstract
Many biological processes involve the mechanistic/mammalian target of rapamycin complex 1 (mTORC1). Thus, the challenge of deciphering mTORC1-mediated functions during normal and pathological states in the central nervous system is challenging. Because mTORC1 is at the core of translation, we have investigated mTORC1 function in global and regional protein expression. Activation of mTORC1 has been generally regarded to promote translation. Few but recent works have shown that suppression of mTORC1 can also promote local protein synthesis. Moreover, excessive mTORC1 activation during diseased states represses basal and activity-induced protein synthesis. To determine the role of mTORC1 activation in protein expression, we have used an unbiased, large-scale proteomic approach. We provide evidence that a brief repression of mTORC1 activity in vivo by rapamycin has little effect globally, yet leads to a significant remodeling of synaptic proteins, in particular those proteins that reside in the postsynaptic density. We have also found that curtailing the activity of mTORC1 bidirectionally alters the expression of proteins associated with epilepsy, Alzheimer's disease, and autism spectrum disorder-neurological disorders that exhibit elevated mTORC1 activity. Through a protein-protein interaction network analysis, we have identified common proteins shared among these mTORC1-related diseases. One such protein is Parkinson protein 7, which has been implicated in Parkinson's disease, yet not associated with epilepsy, Alzheimers disease, or autism spectrum disorder. To verify our finding, we provide evidence that the protein expression of Parkinson protein 7, including new protein synthesis, is sensitive to mTORC1 inhibition. Using a mouse model of tuberous sclerosis complex, a disease that displays both epilepsy and autism spectrum disorder phenotypes and has overactive mTORC1 signaling, we show that Parkinson protein 7 protein is elevated in the dendrites and colocalizes with the postsynaptic marker postsynaptic density-95. Our work offers a comprehensive view of mTORC1 and its role in regulating regional protein expression in normal and diseased states.
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Affiliation(s)
- Farr Niere
- From the ‡Center for Learning and Memory, University of Texas, Austin, 1 University Station C7000, Texas 78712; §Institute for Cell and Molecular Biology, University of Texas, Austin, Texas; ¶Institute for Neuroscience, University of Texas, Austin, Texas; ‖Waggoner Center for Alcohol and Addiction Research, University of Texas, Austin, Texas
| | - Sanjeev Namjoshi
- From the ‡Center for Learning and Memory, University of Texas, Austin, 1 University Station C7000, Texas 78712; §Institute for Cell and Molecular Biology, University of Texas, Austin, Texas
| | - Ehwang Song
- **Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409
| | - Geoffrey A Dilly
- From the ‡Center for Learning and Memory, University of Texas, Austin, 1 University Station C7000, Texas 78712; §Institute for Cell and Molecular Biology, University of Texas, Austin, Texas; ¶Institute for Neuroscience, University of Texas, Austin, Texas
| | - Grant Schoenhard
- ‡‡Pain Therapeutics, Inc., 7801 N Capital of Texas Hwy, #260, Austin, Texas 78731
| | - Boris V Zemelman
- From the ‡Center for Learning and Memory, University of Texas, Austin, 1 University Station C7000, Texas 78712; §Institute for Cell and Molecular Biology, University of Texas, Austin, Texas; ¶Institute for Neuroscience, University of Texas, Austin, Texas
| | - Yehia Mechref
- **Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409
| | - Kimberly F Raab-Graham
- From the ‡Center for Learning and Memory, University of Texas, Austin, 1 University Station C7000, Texas 78712; §Institute for Cell and Molecular Biology, University of Texas, Austin, Texas; ¶Institute for Neuroscience, University of Texas, Austin, Texas; ‖Waggoner Center for Alcohol and Addiction Research, University of Texas, Austin, Texas; ‡‡Pain Therapeutics, Inc., 7801 N Capital of Texas Hwy, #260, Austin, Texas 78731
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LY395756, an mGluR2 agonist and mGluR3 antagonist, enhances NMDA receptor expression and function in the normal adult rat prefrontal cortex, but fails to improve working memory and reverse MK801-induced working memory impairment. Exp Neurol 2015; 273:190-201. [PMID: 26341392 DOI: 10.1016/j.expneurol.2015.08.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 08/06/2015] [Accepted: 08/25/2015] [Indexed: 11/22/2022]
Abstract
Targeting group II metabotropic glutamate receptors (mGluR2/3) has been proposed to correct the dysfunctional glutamatergic system, particularly NMDA receptor (NMDAR) hypofunction, for treatment of schizophrenia. However, how activation of mGluR2/3 affects NMDAR function in adult animals remains elusive. Here we show the effects of LY395756 (LY39), a compound acting as both an mGluR2 agonist and mGluR3 antagonist, on the NMDAR expression and function of normal adult rat prefrontal cortex (PFC) as well as working memory function in the MK801 model of schizophrenia. We found that in vivo administration of LY39 significantly increased the total protein levels of NMDAR subunits and NR2B phosphorylationin the PFC, along with the amplitude of NMDAR-mediated miniature excitatory postsynaptic currents (mEPSC) in the prefrontal cortical neurons. Moreover, LY39 also significantly increased mTOR and pmTOR expression, but not ERK1/2, Akt, and GSK3β, suggesting an activation of mTOR signaling. Indeed, the mTOR inhibitor rapamycin, and actinomycin-D, a transcription inhibitor, blocked the enhanced effects of LY39 on NMDAR-mEPSCs. These results indicate that LY39 regulates NMDAR expression and function through unidentified mTOR-mediated protein synthesis in the normal adult rat PFC. However, this change is insufficient to affect working memory function in normal animals, nor to reverse the MK801-induced working memory deficit. Our data provide the first evidence of an in vivo effect of a novel compound that acts as both an mGluR2 agonist and mGluR3 antagonist on synaptic NMDAR expression and function in the adult rat PFC, although its effect -on PFC-dependent cognitive function remains to be explored.
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Nikolaeva I, Crowell B, Valenziano J, Meaney D, D'Arcangelo G. Beneficial Effects of Early mTORC1 Inhibition after Traumatic Brain Injury. J Neurotrauma 2015; 33:183-93. [PMID: 26122481 DOI: 10.1089/neu.2015.3899] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The mammalian target of rapamycin complex 1 (mTORC1) signaling pathway mediates many aspects of cell growth and regeneration and is upregulated after moderate to severe traumatic brain injury (TBI). The significance of this increased signaling event for recovery of brain function is presently unclear. We analyzed the time course and cell specificity of mTORC1 signal activation in the mouse hippocampus after moderate controlled cortical impact (CCI) and identified an early neuronal peak of activity that occurs within a few hours after injury. We suppressed this peak activity by a single injection of the mTORC1 inhibitor rapamycin 1 h after CCI and showed that this acute treatment significantly diminishes the extent of neuronal death, astrogliosis, and cognitive impairment 1-3 days after injury. Our findings suggest that the early neuronal peak of mTORC1 activity after TBI is deleterious to brain function, and that acute, early intervention with mTORC1 inhibitors after injury may represent an effective form of treatment to improve recovery in human patients.
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Affiliation(s)
- Ina Nikolaeva
- 1 Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey , Piscataway, New Jersey.,2 Graduate Program in Molecular Bioscience, Rutgers, the State University of New Jersey , Piscataway, New Jersey
| | - Beth Crowell
- 1 Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey , Piscataway, New Jersey
| | - Julia Valenziano
- 3 Department of Bioengineering, University of Pennsylvania , Philadelphia, Pennsylvania
| | - David Meaney
- 3 Department of Bioengineering, University of Pennsylvania , Philadelphia, Pennsylvania
| | - Gabriella D'Arcangelo
- 1 Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey , Piscataway, New Jersey.,2 Graduate Program in Molecular Bioscience, Rutgers, the State University of New Jersey , Piscataway, New Jersey
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Szewczyk B, Pochwat B, Rafało A, Palucha-Poniewiera A, Domin H, Nowak G. Activation of mTOR dependent signaling pathway is a necessary mechanism of antidepressant-like activity of zinc. Neuropharmacology 2015; 99:517-26. [PMID: 26297535 DOI: 10.1016/j.neuropharm.2015.08.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 07/23/2015] [Accepted: 08/16/2015] [Indexed: 12/13/2022]
Abstract
The rapid antidepressant response to the N-methyl-D-aspartate (NMDA) receptor antagonists is mediated by activation of the mammalian target of the rapamycin (mTOR) signaling pathway, an increase in the synthesis of synaptic proteins and formation of new synapses in the prefrontal cortex (PFC) of rats. Zinc (Zn), which is a potent NMDA receptor antagonist, exerts antidepressant-like effects in screening tests and models of depression. We focused these studies in investigating whether activation of the mTOR signaling pathway is also a necessary mechanism of the antidepressant-like activity of Zn. We observed that a single injection of Zn (5 mg/kg) induced an increase in the phosphorylation of mTOR and p70S6K 30 min and 3 h after Zn treatment at time points when Zn produced also an antidepressant-like effect in the forced swim test (FST). Furthermore, Zn administered 3 h before the decapitation increased the level of brain derived neurotrophic factor (BDNF), GluA1 and synapsin I. An elevated level of GluA1 and synapsin I was still observed 24 h after the Zn treatment, although Zn did not produce any effects in the FST at that time point. We also observed that pretreatment with rapamycin (mTORC1 inhibitor), LY294002 (PI3K inhibitor), H-89 (PKA inhibitor) and GF109203X (PKC inhibitor) blocked the antidepressant-like effect of Zn in FST in rats and blocks Zn-induced activation of mTOR signaling proteins (analyzed 30 min after Zn administration). These studies indicated that the antidepressant-like activity of Zn depends on the activation of mTOR signaling and other signaling pathways related to neuroplasticity, which can indirectly modulate mTOR function.
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Affiliation(s)
- Bernadeta Szewczyk
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Krakow, Poland.
| | - Bartłomiej Pochwat
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Krakow, Poland
| | - Anna Rafało
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Krakow, Poland
| | - Agnieszka Palucha-Poniewiera
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Krakow, Poland
| | - Helena Domin
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Krakow, Poland
| | - Gabriel Nowak
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Krakow, Poland; Department of Pharmacobiology, Jagiellonian University Medical College, Medyczna 9, 30-688 Kraków, Poland
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83
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Hsu WL, Chung HW, Wu CY, Wu HI, Lee YT, Chen EC, Fang W, Chang YC. Glutamate Stimulates Local Protein Synthesis in the Axons of Rat Cortical Neurons by Activating α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) Receptors and Metabotropic Glutamate Receptors. J Biol Chem 2015; 290:20748-20760. [PMID: 26134564 DOI: 10.1074/jbc.m115.638023] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Indexed: 12/20/2022] Open
Abstract
Glutamate is the principal excitatory neurotransmitter in the mammalian CNS. By analyzing the metabolic incorporation of azidohomoalanine, a methionine analogue, in newly synthesized proteins, we find that glutamate treatments up-regulate protein translation not only in intact rat cortical neurons in culture but also in the axons emitting from cortical neurons before making synapses with target cells. The process by which glutamate stimulates local translation in axons begins with the binding of glutamate to the ionotropic AMPA receptors and metabotropic glutamate receptor 1 and members of group 2 metabotropic glutamate receptors on the plasma membrane. Subsequently, the activated mammalian target of rapamycin (mTOR) signaling pathway and the rise in Ca(2+), resulting from Ca(2+) influxes through calcium-permeable AMPA receptors, voltage-gated Ca(2+) channels, and transient receptor potential canonical channels, in axons stimulate the local translation machinery. For comparison, the enhancement effects of brain-derived neurotrophic factor (BDNF) on the local protein synthesis in cortical axons were also studied. The results indicate that Ca(2+) influxes via transient receptor potential canonical channels and activated the mTOR pathway in axons also mediate BDNF stimulation to local protein synthesis. However, glutamate- and BDNF-induced enhancements of translation in axons exhibit different kinetics. Moreover, Ca(2+) and mTOR signaling appear to play roles carrying different weights, respectively, in transducing glutamate- and BDNF-induced enhancements of axonal translation. Thus, our results indicate that exposure to transient increases of glutamate and more lasting increases of BDNF would stimulate local protein synthesis in migrating axons en route to their targets in the developing brain.
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Affiliation(s)
- Wei-Lun Hsu
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Hui-Wen Chung
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Chih-Yueh Wu
- Institute of Systems Neuroscience, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Huei-Ing Wu
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Yu-Tao Lee
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
| | - En-Chan Chen
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Weilun Fang
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Yen-Chung Chang
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 300, Taiwan; Institute of Systems Neuroscience, National Tsing Hua University, Hsinchu 300, Taiwan; Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 300, Taiwan.
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84
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Sosanya NM, Cacheaux LP, Workman ER, Niere F, Perrone-Bizzozero NI, Raab-Graham KF. Mammalian Target of Rapamycin (mTOR) Tagging Promotes Dendritic Branch Variability through the Capture of Ca2+/Calmodulin-dependent Protein Kinase II α (CaMKIIα) mRNAs by the RNA-binding Protein HuD. J Biol Chem 2015; 290:16357-71. [PMID: 25944900 DOI: 10.1074/jbc.m114.599399] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Indexed: 02/05/2023] Open
Abstract
The fate of a memory, whether stored or forgotten, is determined by the ability of an active or tagged synapse to undergo changes in synaptic efficacy requiring protein synthesis of plasticity-related proteins. A synapse can be tagged, but without the "capture" of plasticity-related proteins, it will not undergo long lasting forms of plasticity (synaptic tagging and capture hypothesis). What the "tag" is and how plasticity-related proteins are captured at tagged synapses are unknown. Ca(2+)/calmodulin-dependent protein kinase II α (CaMKIIα) is critical in learning and memory and is synthesized locally in neuronal dendrites. The mechanistic (mammalian) target of rapamycin (mTOR) is a protein kinase that increases CaMKIIα protein expression; however, the mechanism and site of dendritic expression are unknown. Herein, we show that mTOR activity mediates the branch-specific expression of CaMKIIα, favoring one secondary, daughter branch over the other in a single neuron. mTOR inhibition decreased the dendritic levels of CaMKIIα protein and mRNA by shortening its poly(A) tail. Overexpression of the RNA-stabilizing protein HuD increased CaMKIIα protein levels and preserved its selective expression in one daughter branch over the other when mTOR was inhibited. Unexpectedly, deleting the third RNA recognition motif of HuD, the domain that binds the poly(A) tail, eliminated the branch-specific expression of CaMKIIα when mTOR was active. These results provide a model for one molecular mechanism that may underlie the synaptic tagging and capture hypothesis where mTOR is the tag, preventing deadenylation of CaMKIIα mRNA, whereas HuD captures and promotes its expression in a branch-specific manner.
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Affiliation(s)
- Natasha M Sosanya
- From the Center for Learning and Memory, Department of Neuroscience, Institute for Cell Biology, and United States Army Institute of Surgical Research, Joint Base San Antonio-Fort Sam, Houston, Texas 78234, and
| | - Luisa P Cacheaux
- From the Center for Learning and Memory, Department of Neuroscience
| | - Emily R Workman
- From the Center for Learning and Memory, Department of Neuroscience, Institute for Neuroscience, University of Texas, Austin, Texas 78712
| | - Farr Niere
- From the Center for Learning and Memory, Department of Neuroscience
| | - Nora I Perrone-Bizzozero
- Department of Neurosciences, Psychiatry and Behavioral Sciences, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Kimberly F Raab-Graham
- From the Center for Learning and Memory, Department of Neuroscience, Institute for Cell Biology, and Institute for Neuroscience, University of Texas, Austin, Texas 78712,
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85
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Rozas NS, Redell JB, Pita-Almenar JD, Mckenna J, Moore AN, Gambello MJ, Dash PK. Intrahippocampal glutamine administration inhibits mTORC1 signaling and impairs long-term memory. ACTA ACUST UNITED AC 2015; 22:239-46. [PMID: 25878136 PMCID: PMC4408772 DOI: 10.1101/lm.038265.115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 02/13/2015] [Indexed: 11/25/2022]
Abstract
The mechanistic Target of Rapamycin Complex 1 (mTORC1), a key regulator of protein synthesis and cellular growth, is also required for long-term memory formation. Stimulation of mTORC1 signaling is known to be dependent on the availability of energy and growth factors, as well as the presence of amino acids. In vitro studies using serum- and amino acid-starved cells have reported that glutamine addition can either stimulate or repress mTORC1 activity, depending on the particular experimental system that was used. However, these experiments do not directly address the effect of glutamine on mTORC1 activity under physiological conditions in nondeprived cells in vivo. We present experimental results indicating that intrahippocampal administration of glutamine to rats reduces mTORC1 activity. Moreover, post-training administration of glutamine impairs long-term spatial memory formation, while coadministration of glutamine with leucine had no influence on memory. Intracellular recordings in hippocampal slices showed that glutamine did not alter either excitatory or inhibitory synaptic activity, suggesting that the observed memory impairments may not result from conversion of glutamine to either glutamate or GABA. Taken together, these findings indicate that glutamine can decrease mTORC1 activity in the brain and may have implications for treatments of neurological diseases associated with high mTORC1 signaling.
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Affiliation(s)
- Natalia S Rozas
- Department of Neurobiology and Anatomy, The University of Texas Medical School, Houston, Texas 77225, USA
| | - John B Redell
- Department of Neurobiology and Anatomy, The University of Texas Medical School, Houston, Texas 77225, USA
| | - Juan D Pita-Almenar
- Department of Neurobiology and Anatomy, The University of Texas Medical School, Houston, Texas 77225, USA
| | - James Mckenna
- Department of Human Genetics, Emory University, Atlanta, Georgia 30322, USA
| | - Anthony N Moore
- Department of Neurobiology and Anatomy, The University of Texas Medical School, Houston, Texas 77225, USA
| | - Michael J Gambello
- Department of Human Genetics, Emory University, Atlanta, Georgia 30322, USA
| | - Pramod K Dash
- Department of Neurobiology and Anatomy, The University of Texas Medical School, Houston, Texas 77225, USA
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86
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Zeng Y, Zhang J, Zhu Y, Zhang J, Shen H, Lu J, Pan X, Lin N, Dai X, Zhou M, Chen X. Tripchlorolide improves cognitive deficits by reducing amyloid β and upregulating synapse-related proteins in a transgenic model of Alzheimer's Disease. J Neurochem 2015; 133:38-52. [DOI: 10.1111/jnc.13056] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 01/21/2015] [Accepted: 01/22/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Yuqi Zeng
- Department of Neurology and Geriatrics; Fujian Institute of Geriatrics; Fujian Medical University Union Hospital; Fuzhou China
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Jian Zhang
- Department of Neurology and Geriatrics; Fujian Institute of Geriatrics; Fujian Medical University Union Hospital; Fuzhou China
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Yuangui Zhu
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Jing Zhang
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Hui Shen
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Jianping Lu
- Department of Neurology and Geriatrics; Fujian Institute of Geriatrics; Fujian Medical University Union Hospital; Fuzhou China
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Xiaodong Pan
- Department of Neurology and Geriatrics; Fujian Institute of Geriatrics; Fujian Medical University Union Hospital; Fuzhou China
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Nan Lin
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Xiaoman Dai
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Meng Zhou
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
| | - Xiaochun Chen
- Department of Neurology and Geriatrics; Fujian Institute of Geriatrics; Fujian Medical University Union Hospital; Fuzhou China
- Key Laboratory of Brain Aging and Neurodegenerative Disease; Fujian Key Laboratory of Molecular Neurology; Fujian Medical University; Fuzhou China
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87
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Ménard C, Gaudreau P, Quirion R. Signaling pathways relevant to cognition-enhancing drug targets. Handb Exp Pharmacol 2015; 228:59-98. [PMID: 25977080 DOI: 10.1007/978-3-319-16522-6_3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Aging is generally associated with a certain cognitive decline. However, individual differences exist. While age-related memory deficits can be observed in humans and rodents in the absence of pathological conditions, some individuals maintain intact cognitive functions up to an advanced age. The mechanisms underlying learning and memory processes involve the recruitment of multiple signaling pathways and gene expression, leading to adaptative neuronal plasticity and long-lasting changes in brain circuitry. This chapter summarizes the current understanding of how these signaling cascades could be modulated by cognition-enhancing agents favoring memory formation and successful aging. It focuses on data obtained in rodents, particularly in the rat as it is the most common animal model studied in this field. First, we will discuss the role of the excitatory neurotransmitter glutamate and its receptors, downstream signaling effectors [e.g., calcium/calmodulin-dependent protein kinase II (CaMKII), protein kinase C (PKC), extracellular signal-regulated kinases (ERK), mammalian target of rapamycin (mTOR), cAMP response element-binding protein (CREB)], associated immediate early gene (e.g., Homer 1a, Arc and Zif268), and growth factors [insulin-like growth factors (IGFs) and brain-derived neurotrophic factor (BDNF)] in synaptic plasticity and memory formation. Second, the impact of the cholinergic system and related modulators on memory will be briefly reviewed. Finally, since dynorphin neuropeptides have recently been associated with memory impairments in aging, it is proposed as an attractive target to develop novel cognition-enhancing agents.
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Affiliation(s)
- Caroline Ménard
- Douglas Mental Health University Institute, McGill University, Perry Pavilion, 6875 LaSalle Boulevard, Montreal, QC, Canada, H4H 1R3
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88
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Most D, Workman E, Harris RA. Synaptic adaptations by alcohol and drugs of abuse: changes in microRNA expression and mRNA regulation. Front Mol Neurosci 2014; 7:85. [PMID: 25565954 PMCID: PMC4267177 DOI: 10.3389/fnmol.2014.00085] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 10/22/2014] [Indexed: 12/18/2022] Open
Abstract
Local translation of mRNAs is a mechanism by which cells can rapidly remodel synaptic structure and function. There is ample evidence for a role of synaptic translation in the neuroadaptations resulting from chronic drug use and abuse. Persistent and coordinated changes of many mRNAs, globally and locally, may have a causal role in complex disorders such as addiction. In this review we examine the evidence that translational regulation by microRNAs drives synaptic remodeling and mRNA expression, which may regulate the transition from recreational to compulsive drug use. microRNAs are small, non-coding RNAs that control the translation of mRNAs in the cell and within spatially restricted sites such as the synapse. microRNAs typically repress the translation of mRNAs into protein by binding to the 3′UTR of their targets. As ‘master regulators’ of many mRNAs, changes in microRNAs could account for the systemic alterations in mRNA and protein expression observed with drug abuse and dependence. Recent studies indicate that manipulation of microRNAs affects addiction-related behaviors such as the rewarding properties of cocaine, cocaine-seeking behavior, and self-administration rates of alcohol. There is limited evidence, however, regarding how synaptic microRNAs control local mRNA translation during chronic drug exposure and how this contributes to the development of dependence. Here, we discuss research supporting microRNA regulation of local mRNA translation and how drugs of abuse may target this process. The ability of synaptic microRNAs to rapidly regulate mRNAs provides a discrete, localized system that could potentially be used as diagnostic and treatment tools for alcohol and other addiction disorders.
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Affiliation(s)
- Dana Most
- The Institute for Neuroscience, The University of Texas at Austin Austin, TX, USA ; Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin Austin, TX, USA
| | - Emily Workman
- The Institute for Neuroscience, The University of Texas at Austin Austin, TX, USA
| | - R Adron Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin Austin, TX, USA
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89
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Vargas-Martínez F, Uvnäs-Moberg K, Petersson M, Olausson HA, Jiménez-Estrada I. Neuropeptides as neuroprotective agents: Oxytocin a forefront developmental player in the mammalian brain. Prog Neurobiol 2014; 123:37-78. [DOI: 10.1016/j.pneurobio.2014.10.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 10/06/2014] [Indexed: 02/07/2023]
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90
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Abstract
A significant portion of the world's population suffers from sporadic Alzheimer's disease (AD) with available present therapies limited to symptomatic care that does not alter disease progression. Over the next decade, advancing age of the global population will dramatically increase the incidence of AD and severely impact health care resources, necessitating novel, safe, and efficacious strategies for AD. The mammalian target of rapamycin (mTOR) and its protein complexes mTOR Complex 1 (mTORC1) and mTOR Complex 2 (mTORC2) offer exciting and unique avenues of intervention for AD through the oversight of programmed cell death pathways of apoptosis, autophagy, and necroptosis. mTOR modulates multi-faceted signal transduction pathways that involve phosphoinositide 3-kinase (PI 3-K), protein kinase B (Akt), hamartin (tuberous sclerosis 1)/ tuberin (tuberous sclerosis 2) (TSC1/TSC2) complex, proline-rich Akt substrate 40 kDa (PRAS40), and p70 ribosomal S6 kinase (p70S6K) and can interface with the neuroprotective pathways of growth factors, sirtuins, wingless, forkhead transcription factors, and glycogen synthase kinase-3β. With the ability of mTOR to broadly impact cellular function, clinical strategies for AD that implement mTOR must achieve parallel objectives of protecting neuronal, vascular, and immune cell survival in conjunction with preserving networks that determine memory and cognitive function.
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Affiliation(s)
- Kenneth Maiese
- Cellular and Molecular Signaling , Newark, New Jersey 07101 , USA
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91
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The mammalian target of rapamycin pathway in the basolateral amygdala is critical for nicotine-induced behavioural sensitization. Int J Neuropsychopharmacol 2014; 17:1881-94. [PMID: 24916432 DOI: 10.1017/s1461145714000650] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Repeated exposure to nicotine increases psychomotor activity. Long-lasting neural plasticity changes that contribute to the nicotine-induced development of locomotor sensitization have been identified. The mammalian target of rapamycin complex 1 (mTORC1) signalling pathway is involved in regulating the neuroplasticity of the central nervous system. In this study, we examined the role of mTORC1 in the amygdala in nicotine-induced locomotor sensitization. Rapamycin, an inhibitor of mTORC1, was infused into the basolateral amygdala (BLA) and central amygdala (CeA) or systemically administered to investigate the role of the mTORC1 in the development and expression of nicotine-induced locomotor sensitization. We found that locomotor activity progressively increased during the initiation of nicotine-induced locomotor sensitization and the expression of nicotine sensitization was induced by nicotine challenge injection (0.35 mg/kg s.c.) after five days of withdrawal. The initiation of nicotine-induced locomotor sensitization was accompanied by the increased phosphorylated level of mTORC1 downstream target proteins including p-p70s6k and p-4EBP in the BLA, but not CeA. Intra-BLA infusion or systemic administration of rapamycin blocked locomotor activity. Increased p-p70s6k and p-4EBP were also observed in the expression of nicotine sensitization, which was demonstrated to be inhibited by systemic rapamycin administration. Our findings indicated that mTORC1 activity in the BLA, but not the CeA, mediated the initiation and expression of nicotine-induced locomotor sensitization, and may become a potential target for the treatment of nicotine addiction.
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92
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Villers A, Giese KP, Ris L. Long-term potentiation can be induced in the CA1 region of hippocampus in the absence of αCaMKII T286-autophosphorylation. ACTA ACUST UNITED AC 2014; 21:616-26. [PMID: 25322797 PMCID: PMC4201817 DOI: 10.1101/lm.035972.114] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
α-calcium/calmodulin-dependent protein kinase (αCaMKII) T286-autophosphorylation provides a short-term molecular memory that was thought to be required for LTP and for learning and memory. However, it has been shown that learning can occur in αCaMKII-T286A mutant mice after a massed training protocol. This raises the question of whether there might be a form of LTP in these mice that can occur without T286 autophosphorylation. In this study, we confirmed that in CA1 pyramidal cells, LTP induced in acute hippocampal slices, after a recovery period in an interface chamber, is strictly dependent on postsynaptic αCaMKII autophosphorylation. However, we demonstrated that αCaMKII-autophosphorylation-independent plasticity can occur in the hippocampus but at the expense of synaptic specificity. This nonspecific LTP was observed in mutant and wild-type mice after a recovery period in a submersion chamber and was independent of NMDA receptors. Moreover, when slices prepared from mutant mice were preincubated during 2 h with rapamycin, high-frequency trains induced a synapse-specific LTP which was added to the nonspecific LTP. This specific LTP was related to an increase in the duration and the amplitude of NMDA receptor-mediated response induced by rapamycin.
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Affiliation(s)
- Agnès Villers
- Department of Neuroscience, Research Institute for Biosciences, University of Mons, B-7000 Mons, Belgium
| | - Karl Peter Giese
- MRC Centre for Neurodegeneration, Institute of Psychiatry, King's College London, SE5 9NU, London, United Kingdom
| | - Laurence Ris
- Department of Neuroscience, Research Institute for Biosciences, University of Mons, B-7000 Mons, Belgium
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93
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Maiese K. Driving neural regeneration through the mammalian target of rapamycin. Neural Regen Res 2014; 9:1413-7. [PMID: 25317149 PMCID: PMC4192939 DOI: 10.4103/1673-5374.139453] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2014] [Indexed: 12/12/2022] Open
Abstract
Neurodegenerative disorders affect more than 30 million individuals throughout the world and lead to significant disability as well as death. These statistics will increase almost exponentially as the lifespan and age of individuals increase globally and individuals become more susceptible to acute disorders such as stroke as well as chronic diseases that involve cognitive loss, Alzheimer's disease, and Parkinson's disease. Current therapies for such disorders are effective only for a small subset of individuals or provide symptomatic relief but do not alter disease progression. One exciting therapeutic approach that may turn the tide for addressing neurodegenerative disorders involves the mammalian target of rapamycin (mTOR). mTOR is a component of the protein complexes mTOR Complex 1 (mTORC1) and mTOR Complex 2 (mTORC2) that are ubiquitous throughout the body and control multiple functions such as gene transcription, metabolism, cell survival, and cell senescence. mTOR through its relationship with phosphoinositide 3-kinase (PI 3-K) and protein kinase B (Akt) and multiple downstream signaling pathways such as p70 ribosomal S6 kinase (p70S6K) and proline rich Akt substrate 40 kDa (PRAS40) promotes neuronal cell regeneration through stem cell renewal and oversees critical pathways such as apoptosis, autophagy, and necroptosis to foster protection against neurodegenerative disorders. Targeting by mTOR of specific pathways that drive long-term potentiation, synaptic plasticity, and β-amyloid toxicity may offer new strategies for disorders such as stroke and Alzheimer's disease. Overall, mTOR is an essential neuroprotective pathway but must be carefully targeted to maximize clinical efficacy and eliminate any clinical toxic side effects.
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94
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Neasta J, Barak S, Ben Hamida S, Ron D. mTOR complex 1: a key player in neuroadaptations induced by drugs of abuse. J Neurochem 2014; 130:172-84. [PMID: 24666346 PMCID: PMC4107045 DOI: 10.1111/jnc.12725] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Revised: 03/19/2014] [Accepted: 03/22/2014] [Indexed: 12/14/2022]
Abstract
The mammalian (or mechanistic) target of rapamycin (mTOR) complex 1 (mTORC1) is a serine and threonine kinase that regulates cell growth, survival, and proliferation. mTORC1 is a master controller of the translation of a subset of mRNAs. In the central nervous system mTORC1 plays a crucial role in mechanisms underlying learning and memory by controlling synaptic protein synthesis. Here, we review recent evidence suggesting that the mTORC1 signaling pathway promotes neuroadaptations following exposure to a diverse group of drugs of abuse including stimulants, cannabinoids, opiates, and alcohol. We further describe potential molecular mechanisms by which drug-induced mTORC1 activation may alter brain functions. Finally, we propose that mTORC1 is a focal point shared by drugs of abuse to mediate drug-related behaviors such as reward seeking and excessive drug intake, and offer future directions to decipher the contribution of the kinase to mechanisms underlying addiction. Recent studies suggesting that exposure to diverse classes of drugs of abuse as well as exposure to drug-associated memories lead to mTORC1 kinase activation in the limbic system. In turn, mTORC1 controls the onset and the maintenance of pathological neuroadaptions that underlie several features of drug addiction such as drug seeking and relapse. Therefore, we propose that targeting mTORC1 and its effectors is a promising strategy to treat drug disorders.
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Affiliation(s)
- Jeremie Neasta
- Department of Neurology, University of California, San Francisco, California, 94143
- The Gallo Research Center, University of California, San Francisco, California, 94143
| | - Segev Barak
- Department of Neurology, University of California, San Francisco, California, 94143
- The Gallo Research Center, University of California, San Francisco, California, 94143
| | - Sami Ben Hamida
- Department of Neurology, University of California, San Francisco, California, 94143
- The Gallo Research Center, University of California, San Francisco, California, 94143
| | - Dorit Ron
- Department of Neurology, University of California, San Francisco, California, 94143
- The Gallo Research Center, University of California, San Francisco, California, 94143
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95
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Takei N, Nawa H. mTOR signaling and its roles in normal and abnormal brain development. Front Mol Neurosci 2014; 7:28. [PMID: 24795562 PMCID: PMC4005960 DOI: 10.3389/fnmol.2014.00028] [Citation(s) in RCA: 218] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 03/30/2014] [Indexed: 11/15/2022] Open
Abstract
Target of rapamycin (TOR) was first identified in yeast as a target molecule of rapamycin, an anti-fugal and immunosuppressant macrolide compound. In mammals, its orthologue is called mammalian TOR (mTOR). mTOR is a serine/threonine kinase that converges different extracellular stimuli, such as nutrients and growth factors, and diverges into several biochemical reactions, including translation, autophagy, transcription, and lipid synthesis among others. These biochemical reactions govern cell growth and cause cells to attain an anabolic state. Thus, the disruption of mTOR signaling is implicated in a wide array of diseases such as cancer, diabetes, and obesity. In the central nervous system, the mTOR signaling cascade is activated by nutrients, neurotrophic factors, and neurotransmitters that enhances protein (and possibly lipid) synthesis and suppresses autophagy. These processes contribute to normal neuronal growth by promoting their differentiation, neurite elongation and branching, and synaptic formation during development. Therefore, disruption of mTOR signaling may cause neuronal degeneration and abnormal neural development. While reduced mTOR signaling is associated with neurodegeneration, excess activation of mTOR signaling causes abnormal development of neurons and glia, leading to brain malformation. In this review, we first introduce the current state of molecular knowledge of mTOR complexes and signaling in general. We then describe mTOR activation in neurons, which leads to translational enhancement, and finally discuss the link between mTOR and normal/abnormal neuronal growth during development.
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Affiliation(s)
- Nobuyuki Takei
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University Niigata, Japan
| | - Hiroyuki Nawa
- Department of Molecular Neurobiology, Brain Research Institute, Niigata University Niigata, Japan
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96
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Prolonged abstinence from developmental cocaine exposure dysregulates BDNF and its signaling network in the medial prefrontal cortex of adult rats. Int J Neuropsychopharmacol 2014; 17:625-34. [PMID: 24345425 DOI: 10.1017/s1461145713001454] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Although evidence exists that chronic cocaine exposure during adulthood is associated with changes in BDNF expression, whether and how cocaine exposure during adolescence modulates BDNF is still unknown. To address this issue, we exposed rats to repeated cocaine injections from post-natal day (PD) 28 to PD 42, a period that roughly approximates adolescence in humans, and we carried out a detailed analysis of the BDNF system in the medial prefrontal cortex (mPFC) of rats sacrificed 3 d (PD 45) and 48 d (PD 90) after the last cocaine treatment. We found that developmental exposure to cocaine altered transcriptional and translational mechanisms governing neurotrophin expression. Total BDNF mRNA levels, in fact, were enhanced in the mPFC of PD 90 rats exposed to cocaine in adolescence, an effect sustained by changes in BDNF exon IV through the transcription factors CaRF and NF-kB. While a profound reduction of specific BDNF-related miRNAs (let7d, miR124 and miR132) may contribute to explaining the increased proBDNF levels, the up-regulation of the extracellular proteases tPA is indicative of increased processing leading to higher levels of released mBDNF. These changes were associated with increased activation of the trkB-Akt pathway resulting in enhanced pmTOR and pS6 kinase, which ultimately produced an up-regulation of Arc and a consequent reduction of GluA1 expression in the mPFC of PD 90 cocaine-treated rats. These findings demonstrate that developmental exposure to cocaine dynamically dysregulates BDNF and its signaling network in the mPFC of adult rats, providing novel mechanisms that may contribute to cocaine-induced changes in synaptic plasticity.
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97
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Arnold SE, Lucki I, Brookshire BR, Carlson GC, Browne CA, Kazi H, Bang S, Choi BR, Chen Y, McMullen MF, Kim SF. High fat diet produces brain insulin resistance, synaptodendritic abnormalities and altered behavior in mice. Neurobiol Dis 2014; 67:79-87. [PMID: 24686304 DOI: 10.1016/j.nbd.2014.03.011] [Citation(s) in RCA: 227] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 03/02/2014] [Accepted: 03/20/2014] [Indexed: 12/29/2022] Open
Abstract
Insulin resistance and other features of the metabolic syndrome are increasingly recognized for their effects on cognitive health. To ascertain mechanisms by which this occurs, we fed mice a very high fat diet (60% kcal by fat) for 17days or a moderate high fat diet (HFD, 45% kcal by fat) for 8weeks and examined changes in brain insulin signaling responses, hippocampal synaptodendritic protein expression, and spatial working memory. Compared to normal control diet mice, cerebral cortex tissues of HFD mice were insulin-resistant as evidenced by failed activation of Akt, S6 and GSK3β with ex-vivo insulin stimulation. Importantly, we found that expression of brain IPMK, which is necessary for mTOR/Akt signaling, remained decreased in HFD mice upon activation of AMPK. HFD mouse hippocampus exhibited increased expression of serine-phosphorylated insulin receptor substrate 1 (IRS1-pS(616)), a marker of insulin resistance, as well as decreased expression of PSD-95, a scaffolding protein enriched in post-synaptic densities, and synaptopodin, an actin-associated protein enriched in spine apparatuses. Spatial working memory was impaired as assessed by decreased spontaneous alternation in a T-maze. These findings indicate that HFD is associated with telencephalic insulin resistance and deleterious effects on synaptic integrity and cognitive behaviors.
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Affiliation(s)
- Steven E Arnold
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, 125 South 31st St, Philadelphia, PA 19104, USA.
| | - Irwin Lucki
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, 125 South 31st St, Philadelphia, PA 19104, USA
| | - Bethany R Brookshire
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, 125 South 31st St, Philadelphia, PA 19104, USA
| | - Gregory C Carlson
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, 125 South 31st St, Philadelphia, PA 19104, USA
| | - Caroline A Browne
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, 125 South 31st St, Philadelphia, PA 19104, USA
| | - Hala Kazi
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, 125 South 31st St, Philadelphia, PA 19104, USA
| | - Sookhee Bang
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, 125 South 31st St, Philadelphia, PA 19104, USA
| | - Bo-Ran Choi
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, 125 South 31st St, Philadelphia, PA 19104, USA
| | - Yong Chen
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, 125 South 31st St, Philadelphia, PA 19104, USA
| | - Mary F McMullen
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, 125 South 31st St, Philadelphia, PA 19104, USA
| | - Sangwon F Kim
- Center for Neurobiology and Behavior, Department of Psychiatry, University of Pennsylvania, 125 South 31st St, Philadelphia, PA 19104, USA.
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98
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Rachalski A, Freyburger M, Mongrain V. Contribution of transcriptional and translational mechanisms to the recovery aspect of sleep regulation. Ann Med 2014; 46:62-72. [PMID: 24428734 DOI: 10.3109/07853890.2013.866439] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Sleep parallels brain functioning and mental health. Neuronal activity during wakefulness leads to a subsequent increase in sleep intensity as measured using electroencephalographic slow-wave activity (SWA; index of neuronal synchrony in the low-frequency range). Wakefulness, and particularly prolonged wakefulness, also drives important changes in brain gene expression and changes in protein regulation. The role of these two cellular mechanisms in sleep-wake regulation has typically been studied independently, and their exact contribution to SWA remains poorly defined. In this review, we highlight that many transcriptional pathways driven by sleep deprivation are associated to protein regulation. We first describe the relationship between cytokines, clock genes, and markers of sleep need with an emphasis on transcriptional processes. Observations regarding the role of protein metabolism in sleep-wake regulation are then depicted while presenting interconnections between transcriptional and translational responses driven by sleep loss. Lastly, a manner by which this integrated response can feed back on neuronal network activity to determine sleep intensity is proposed. Overall, the literature supports that a complex cross-talk between transcriptional and translational regulation during prolonged wakefulness drives the changes in sleep intensity as a function of the sleep/wake history.
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Affiliation(s)
- Adeline Rachalski
- Center for Advanced Research in Sleep Medicine and Research Center, Hôpital du Sacré-Coeur de Montréal , Montréal, QC , Canada
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99
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Canpolat M, Per H, Gumus H, Yikilmaz A, Unal E, Patiroglu T, Cinar L, Kurtsoy A, Kumandas S. Rapamycin has a beneficial effect on controlling epilepsy in children with tuberous sclerosis complex: results of 7 children from a cohort of 86. Childs Nerv Syst 2014; 30:227-40. [PMID: 23743820 DOI: 10.1007/s00381-013-2185-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Accepted: 05/23/2013] [Indexed: 01/03/2023]
Abstract
PURPOSE Tuberous sclerosis complex (TSC) is a genetic disorder characterized by the formation of hamartomas in various organ systems. We would like share our experience from 86 patients and the results of rapamycin treatment in seven children with TSC. METHODS Eighty-six children with TSC were enrolled into this retrospective study. The clinical features of seven children treated with oral rapamycin were presented in detail. RESULTS The most common complaint of administration was convulsion in 77 children (89.5%). Hypopigmented skin lesions, adenoma sebaceum, resistant epilepsy, intracardiac mass, renal angiomyolipomas, and West syndrome were detected (n = 83, 96.5%; n = 47, 54.7%; n = 36, 41.9%; n = 27, 31.4%; n = 18, 20.9%; and n = 13, 15.1%, respectively). Subependymal nodules were the most frequent finding in cranial imaging followed by cortical tubers and subependymal giant cell astrocytomas (n = 75, 87.2%; n = 71, 82.6%; and n = 8, 9.3%, respectively). Of the seven patients treated with rapamycin, the lesions of six children with facial adenoma sebaceum showed regression in various degrees. The frequency of convulsions decreased in five patients with resistant epilepsy within the first 6 months of the treatment, and complete control of convulsion for all patients was achieved in the second 6 months. CONCLUSION This is the first study that showed that rapamycin is an effective agent for controlling epilepsy without any significant side effect in children with TSC. Rapamycin seems to be effective after 6 months of therapy, and we recommend tapering the dosage after successful management of epilepsy.
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Affiliation(s)
- Mehmet Canpolat
- Department of Pediatrics, Division of Pediatric Neurology, Faculty of Medicine, Erciyes University, 38039, Kayseri, Turkey
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Curatolo P, D’Argenzio L, Cerminara C, Bombardieri R. Management of epilepsy in tuberous sclerosis complex. Expert Rev Neurother 2014; 8:457-67. [DOI: 10.1586/14737175.8.3.457] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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