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Emanetci E, Çakır T. Network-Based Analysis of Cognitive Impairment and Memory Deficits from Transcriptome Data. J Mol Neurosci 2021; 71:2415-2428. [PMID: 33713319 DOI: 10.1007/s12031-021-01807-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 02/01/2021] [Indexed: 12/12/2022]
Abstract
Aging is an inevitable process that negatively affects all living organisms and their vital functions. The brain is one of the most important organs in living beings and is primarily impacted by aging. The molecular mechanisms of learning, memory and cognition are altered over time, and the impairment in these mechanisms can lead to neurodegenerative diseases. Transcriptomics can be used to study these impairments to acquire more detailed information on the affected molecular mechanisms. Here we analyzed learning- and memory-related transcriptome data by mapping it on the organism-specific protein-protein interactome network. Subnetwork discovery algorithms were applied to discover highly dysregulated subnetworks, which were complemented with co-expression-based interactions. The functional analysis shows that the identified subnetworks are enriched with genes having roles in synaptic plasticity, gliogenesis, neurogenesis and cognition, which are reported to be related to memory and learning. With a detailed analysis, we show that the results from different subnetwork discovery algorithms or from different transcriptomic datasets can be successfully reconciled, leading to a memory-learning network that sheds light on the molecular mechanisms behind aging and memory-related impairments.
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Affiliation(s)
- Elif Emanetci
- Department of Bioengineering, Gebze Technical University, 41400, Gebze, Kocaeli, Turkey
| | - Tunahan Çakır
- Department of Bioengineering, Gebze Technical University, 41400, Gebze, Kocaeli, Turkey.
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2
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Kron NS, Schmale MC, Fieber LA. Changes in Metabolism and Proteostasis Drive Aging Phenotype in Aplysia californica Sensory Neurons. Front Aging Neurosci 2020; 12:573764. [PMID: 33101008 PMCID: PMC7522570 DOI: 10.3389/fnagi.2020.573764] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 08/12/2020] [Indexed: 12/29/2022] Open
Abstract
Aging is associated with cognitive declines that originate in impairments of function in the neurons that make up the nervous system. The marine mollusk Aplysia californica (Aplysia) is a premier model for the nervous system uniquely suited to investigation of neuronal aging due to uniquely identifiable neurons and molecular techniques available in this model. This study describes the molecular processes associated with aging in two populations of sensory neurons in Aplysia by applying RNA sequencing technology across the aging process (age 6-12 months). Differentially expressed genes clustered into four to five coherent expression patterns across the aging time series in the two neuron populations. Enrichment analysis of functional annotations in these neuron clusters revealed decreased expression of pathways involved in energy metabolism and neuronal signaling, suggesting that metabolic and signaling pathways are intertwined. Furthermore, increased expression of pathways involved in protein processing and translation suggests that proteostatic stress also occurs in aging. Temporal overlap of enrichment for energy metabolism, proteostasis, and neuronal function suggests that cognitive impairments observed in advanced age result from the ramifications of broad declines in energy metabolism.
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Affiliation(s)
- Nicholas S Kron
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States
| | - Michael C Schmale
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States
| | - Lynne A Fieber
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States
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3
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Alexandrescu A, Carew TJ. Postsynaptic effects of Aplysia cysteine-rich neurotrophic factor in the induction of activity-dependent long-term facilitation in Aplysia californica. ACTA ACUST UNITED AC 2020; 27:124-129. [PMID: 32179654 PMCID: PMC7079570 DOI: 10.1101/lm.051011.119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 12/18/2019] [Indexed: 12/23/2022]
Abstract
The spatial and temporal coordination of growth factor signaling is critical for both presynaptic and postsynaptic plasticity underlying long-term memory formation. We investigated the spatiotemporal dynamics of Aplysia cysteine-rich neurotrophic factor (ApCRNF) signaling during the induction of activity-dependent long-term facilitation (AD-LTF) at sensory-to-motor neuron synapses that mediate defensive reflexes in Aplysia We found that ApCRNF signaling is required for the induction of AD-LTF, and for training-induced early protein kinase activation and late forms of gene expression, exclusively in postsynaptic neurons. These results support the view that ApCRNF is critically involved in AD-LTF at least in part through postsynaptic mechanisms.
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Affiliation(s)
- Anamaria Alexandrescu
- Neuroscience Institute, New York University School of Medicine, New York, New York 10016, USA
| | - Thomas J Carew
- Center for Neural Science, New York University, New York, New York 10003, USA
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4
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Chatterji R, Khoury S, Salas E, Wainwright ML, Mozzachiodi R. Critical role of protein kinase G in the long-term balance between defensive and appetitive behaviors induced by aversive stimuli in Aplysia. Behav Brain Res 2020; 383:112504. [PMID: 31981653 DOI: 10.1016/j.bbr.2020.112504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/21/2020] [Accepted: 01/22/2020] [Indexed: 11/25/2022]
Abstract
This study investigated the signaling cascades involved in the long-term storage of the balance between defensive and appetitive behaviors observed when the mollusk Aplysia is exposed to aversive experience. In Aplysia, repeated trials of aversive stimuli induce concurrent sensitization of defensive withdrawal reflexes and suppression of feeding for at least 24 h. This long-term storage of the balance between withdrawal reflexes and feeding is sustained, at least in part, by increased excitability of the tail sensory neurons (SNs) controlling the withdrawal reflexes, and by decreased excitability of feeding decision-making neuron B51. Nitric oxide (NO) is required for the induction of both long-term sensitization and feeding suppression. At the cellular level, NO is also required for long-term decreased B51 excitability but not for long-term increased SN excitability. Here, we characterized the signaling cascade downstream of NO contributing to the long-term storage of the balance between withdrawal reflexes and feeding. We found protein kinase G (PKG) necessary for both long-term sensitization and feeding suppression, indicating that a NO-PKG cascade governs the long-term storage of the balance between defensive and appetitive responses in Aplysia. The role of PKG on feeding suppression was paralleled at the cellular level where a cGMP-PKG pathway was required for long-term decreased B51 excitability. In the defensive circuit, the cGMP-PKG pathway was not necessary for long-term increased SN excitability, suggesting that other cellular correlates of long-term sensitization might depend on the GMP-PKG cascade to sustain the behavioral change.
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Affiliation(s)
- Ruma Chatterji
- Department of Life Sciences, Texas A&M University - Corpus Christi, Corpus Christi, Texas 78412, USA; Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45221, USA
| | - Sarah Khoury
- Department of Life Sciences, Texas A&M University - Corpus Christi, Corpus Christi, Texas 78412, USA; Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, Texas 78229, USA
| | - Emanuel Salas
- Department of Life Sciences, Texas A&M University - Corpus Christi, Corpus Christi, Texas 78412, USA
| | - Marcy L Wainwright
- Department of Life Sciences, Texas A&M University - Corpus Christi, Corpus Christi, Texas 78412, USA
| | - Riccardo Mozzachiodi
- Department of Life Sciences, Texas A&M University - Corpus Christi, Corpus Christi, Texas 78412, USA.
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5
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Livingstone RW, Elder MK, Barrett MC, Westlake CM, Peppercorn K, Tate WP, Abraham WC, Williams JM. Secreted Amyloid Precursor Protein-Alpha Promotes Arc Protein Synthesis in Hippocampal Neurons. Front Mol Neurosci 2019; 12:198. [PMID: 31474829 PMCID: PMC6702288 DOI: 10.3389/fnmol.2019.00198] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 07/30/2019] [Indexed: 12/22/2022] Open
Abstract
Secreted amyloid precursor protein-α (sAPPα) is a neuroprotective and memory-enhancing molecule, however, the mechanisms through which sAPPα promotes these effects are not well understood. Recently, we have shown that sAPPα enhances cell-surface expression of glutamate receptors. Activity-related cytoskeletal-associated protein Arc (Arg3.1) is an immediate early gene capable of modulating long-term potentiation, long-term depression and homeostatic plasticity through regulation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor localization. Accordingly, we hypothesized that sAPPα may enhance synaptic plasticity, in part, by the de novo synthesis of Arc. Using primary cortical and hippocampal neuronal cultures we found that sAPPα (1 nM, 2 h) enhances levels of Arc mRNA and protein. Arc protein levels were increased in both the neuronal somata and dendrites in a Ca2+/calmodulin-dependent protein kinase II-dependent manner. Additionally, dendritic Arc expression was dependent upon activation of mitogen-activated protein kinase and protein kinase G. The enhancement of dendritic Arc protein was significantly reduced by antagonism of N-methyl-D-aspartate (NMDA) and nicotinic acetylcholine (α7nACh) receptors, and fully eliminated by dual application of these antagonists. This effect was further corroborated in area CA1 of acute hippocampal slices. These data suggest sAPPα-regulated plasticity within hippocampal neurons is mediated by cooperation of NMDA and α7nACh receptors to engage a cascade of signal transduction molecules to enhance the transcription and translation of Arc.
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Affiliation(s)
- Rhys W Livingstone
- Department of Anatomy, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Megan K Elder
- Department of Anatomy, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Maya C Barrett
- Department of Anatomy, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Courteney M Westlake
- Department of Anatomy, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Katie Peppercorn
- Department of Biochemistry, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Warren P Tate
- Department of Biochemistry, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Wickliffe C Abraham
- Department of Psychology, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Joanna M Williams
- Department of Anatomy, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
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6
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McManus JM, Chiel HJ, Susswein AJ. Successful and unsuccessful attempts to swallow in a reduced Aplysia preparation regulate feeding responses and produce memory at different neural sites. ACTA ACUST UNITED AC 2019; 26:151-165. [PMID: 30992384 PMCID: PMC6478246 DOI: 10.1101/lm.048983.118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 03/12/2019] [Indexed: 01/26/2023]
Abstract
Sensory feedback shapes ongoing behavior and may produce learning and memory. Motor responses to edible or inedible food in a reduced Aplysia preparation were examined to test how sensory feedback affects behavior and memory. Feeding patterns were initiated by applying a cholinomimetic onto the cerebral ganglion. Feedback from buccal muscles increased the response variability and response rate. Repeated application of the cholinomimetic caused decreased responses, expressed in part by lengthening protractions. Swallowing strips of "edible" food, which in intact animals induces learning that enhances ingestion, increased the response rate, and shortened the protraction length, reflecting more swallowing. Testing memory by repeating the procedure prevented the decrease in response rate observed with the cholinomimetic alone, and shortened protractions. Training with "inedible" food that in intact animals produces learning expressed by decreased responses caused lengthened protractions. Testing memory by repeating the procedure did not cause decreased responses or lengthened protractions. After training and testing with edible or inedible food, all preparations were exposed to the cholinomimetic alone. Preparations previously trained with edible food displayed memory expressed as decreased protraction length. Preparations previously trained with inedible food showed decreases in many response parameters. Memory for inedible food may arise in part via a postsynaptic decrease in response to acetylcholine released by afferents sensing food. The lack of change in response number, and in the time that responses are maintained during the two training sessions preceding application of the cholinomimetic alone suggests that memory expression may differ from behavioral changes during training.
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Affiliation(s)
- Jeffrey M McManus
- Departments of Biology, Case Western Reserve University, Cleveland, Ohio 44106-7080, USA
| | - Hillel J Chiel
- Departments of Biology, Case Western Reserve University, Cleveland, Ohio 44106-7080, USA.,Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio 44106-7080, USA.,Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106-7080, USA
| | - Abraham J Susswein
- The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan, 52900, Israel.,The Leslie and Susan Gonda (Goldschmied) Multidisciplinary Brain Research Center, Bar Ilan University, Ramat Gan, 52900, Israel
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7
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8
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Farruggella J, Acebo J, Lloyd L, Wainwright ML, Mozzachiodi R. Role of nitric oxide in the induction of the behavioral and cellular changes produced by a common aversive stimulus in Aplysia. Behav Brain Res 2018; 360:341-353. [PMID: 30528940 DOI: 10.1016/j.bbr.2018.12.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 12/04/2018] [Accepted: 12/05/2018] [Indexed: 10/27/2022]
Abstract
Although it is well documented that exposure to aversive stimuli induces modulation of neural circuits and subsequent behavioral changes, the means by which an aversive stimulus concomitantly alters behaviors of different natures (e.g., defensive and appetitive) remains unclear. Here, we addressed this issue by using the learning-induced concurrent modulation of defensive and appetitive behaviors that occurs when the mollusk Aplysia is exposed to aversive stimuli. In Aplysia, aversive stimuli concomitantly enhance withdrawal reflexes (i.e., sensitization) and suppress feeding. Sensitization and feeding suppression, which are expressed in the short term and long term, depending on the training protocol, are accompanied by increased excitability of the tail sensory neurons (TSNs) controlling the withdrawal reflexes, and by decreased excitability of feeding decision-making neuron B51, respectively. Serotonin (5-HT) has been shown to mediate sensitization, but not feeding suppression. In this study, we examined which other neurotransmitter might be responsible for feeding suppression and its underlying cellular changes. Our results indicate that nitric oxide (NO) contributes to both short-term and long-term feeding suppression, as well as to the underlying decreased B51 excitability. NO was also necessary for the induction of long-term sensitization and for the expression of short-term increased TSN excitability in vitro, revealing a previously undocumented interaction between 5-HT and NO signaling cascades in sensitization. Overall, these results revealed a scenario in which multiple modulators contribute to the widespread changes induced by sensitizing stimuli in Aplysia.
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Affiliation(s)
- Jesse Farruggella
- Department of Life Sciences, Texas A&M University - Corpus Christi, 6300 Ocean Drive, Unit 5800, Corpus Christi, TX, 78412, USA
| | - Jonathan Acebo
- Department of Life Sciences, Texas A&M University - Corpus Christi, 6300 Ocean Drive, Unit 5800, Corpus Christi, TX, 78412, USA
| | - Leah Lloyd
- Department of Life Sciences, Texas A&M University - Corpus Christi, 6300 Ocean Drive, Unit 5800, Corpus Christi, TX, 78412, USA
| | - Marcy L Wainwright
- Department of Life Sciences, Texas A&M University - Corpus Christi, 6300 Ocean Drive, Unit 5800, Corpus Christi, TX, 78412, USA
| | - Riccardo Mozzachiodi
- Department of Life Sciences, Texas A&M University - Corpus Christi, 6300 Ocean Drive, Unit 5800, Corpus Christi, TX, 78412, USA.
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9
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Smolen P, Baxter DA, Byrne JH. Paradoxical LTP maintenance with inhibition of protein synthesis and the proteasome suggests a novel protein synthesis requirement for early LTP reversal. J Theor Biol 2018; 457:79-87. [PMID: 30138630 PMCID: PMC6179370 DOI: 10.1016/j.jtbi.2018.08.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/14/2018] [Accepted: 08/18/2018] [Indexed: 11/29/2022]
Abstract
The transition from early long-term potentiation (E-LTP) to late long-term potentiation (L-LTP) is a multistep process that involves both protein synthesis and degradation. The ways in which these two opposing processes interact to establish L-LTP are not well understood, however. For example, L-LTP is attenuated by inhibiting either protein synthesis or proteasome-dependent degradation prior to and during a tetanic stimulus (e.g., Huang et al., 1996; Karpova et al., 2006), but paradoxically, L-LTP is not attenuated when synthesis and degradation are inhibited simultaneously (Fonseca et al., 2006). These paradoxical results suggest that counter-acting 'positive' and 'negative' proteins regulate L-LTP. To investigate the basis of this paradox, we developed a model of LTP at the Schaffer collateral to CA1 pyramidal cell synapse. The model consists of nine ordinary differential equations that describe the levels of both positive- and negative-regulator proteins (PP and NP, respectively) and the transitions among five discrete synaptic states, including a basal state (BAS), three states corresponding to E-LTP (EP1, EP2, and ED), and a L-LTP state (LP). An LTP-inducing stimulus: 1) initiates the transition from BAS to EP1 and from EP1 to EP2; 2) initiates the synthesis of PP and NP; and finally; 3) activates the ubiquitin-proteasome system (UPS), which in turn, mediates transitions of EP1 and EP2 to ED and the degradation of NP. The conversion of E-LTP to L-LTP is mediated by the PP-dependent transition from ED to LP, whereas NP mediates reversal of EP2 to BAS. We found that the inclusion of the five discrete synaptic states was necessary to simulate key empirical observations: 1) normal L-LTP, 2) block of L-LTP by either proteasome inhibitor or protein synthesis inhibitor alone, and 3) preservation of L-LTP when both inhibitors are applied together. Although our model is abstract, elements of the model can be correlated with specific molecular processes. Moreover, the model correctly captures the dynamics of protein synthesis- and degradation-dependent phases of LTP, and it makes testable predictions, such as a unique synaptic state (ED) that precedes the transition from E-LTP to L-LTP, and a well-defined time window for the action of the UPS (i.e., during the transitions from EP1 and EP2 to ED). Tests of these predictions will provide new insights into the processes and dynamics of long-term synaptic plasticity.
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Affiliation(s)
- Paul Smolen
- Laboratory of Origin: Department of Neurobiology and Anatomy, W. M. Keck Center for the Neurobiology of Learning and Memory, McGovern Medical School of the University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
| | - Douglas A Baxter
- Laboratory of Origin: Department of Neurobiology and Anatomy, W. M. Keck Center for the Neurobiology of Learning and Memory, McGovern Medical School of the University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - John H Byrne
- Laboratory of Origin: Department of Neurobiology and Anatomy, W. M. Keck Center for the Neurobiology of Learning and Memory, McGovern Medical School of the University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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10
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Goldner A, Farruggella J, Wainwright ML, Mozzachiodi R. cGMP mediates short- and long-term modulation of excitability in a decision-making neuron in Aplysia. Neurosci Lett 2018; 683:111-118. [PMID: 29960055 DOI: 10.1016/j.neulet.2018.06.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 05/17/2018] [Accepted: 06/22/2018] [Indexed: 01/11/2023]
Abstract
In elementary neural circuits, changes in excitability can have a strong impact in the expression of a given behavior. One example is provided by B51, a neuron with decision-making properties in the feeding neural circuit of the mollusk Aplysia. The excitability of B51 is bidirectionally modulated by external and internal stimuli in a manner that is consistent with the corresponding induced changes in feeding behavior. For example, in operant reward learning, which up-regulates feeding, B51 excitability is increased via a cAMP-dependent mechanism. Conversely, following training protocols with aversive stimuli, which down-regulate feeding, B51 excitability is decreased. In this study, we tested the hypothesis that B51 decreased excitability may be mediated by another cyclic nucleotide, cGMP. Our results revealed that iontophoretic injection of cGMP was capable of inducing both short-term (45 min) and long-term (24 h) reduction of B51 excitability. We next investigated which biochemical trigger could increase cGMP cytosolic levels. The neurotransmitter nitric oxide was found to decrease B51 excitability through the activation of the soluble guanylyl cyclase. These findings indicate that a cGMP-dependent pathway modulates B51 excitability in a manner opposite of cAMP, indicating that distinct cyclic-nucleotide pathways bidirectionally regulate the excitability of a decision-making neuron.
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Affiliation(s)
- Amanda Goldner
- Department of Life Sciences, Texas A&M University - Corpus Christi, Corpus Christi, Texas 78412, USA
| | - Jesse Farruggella
- Department of Life Sciences, Texas A&M University - Corpus Christi, Corpus Christi, Texas 78412, USA
| | - Marcy L Wainwright
- Department of Life Sciences, Texas A&M University - Corpus Christi, Corpus Christi, Texas 78412, USA
| | - Riccardo Mozzachiodi
- Department of Life Sciences, Texas A&M University - Corpus Christi, Corpus Christi, Texas 78412, USA.
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11
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Briskin-Luchinsky V, Levy R, Halfon M, Susswein AJ. Molecular correlates of separate components of training that contribute to long-term memory formation after learning that food is inedible in Aplysia. ACTA ACUST UNITED AC 2018; 25:90-99. [PMID: 29339560 PMCID: PMC5772390 DOI: 10.1101/lm.046326.117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 12/04/2017] [Indexed: 12/21/2022]
Abstract
Training Aplysia with inedible food for a period that is too brief to produce long-term memory becomes effective in producing memory when training is paired with a nitric oxide (NO) donor. Lip stimulation for the same period of time paired with an NO donor is ineffective. Using qPCR, we examined molecular correlates of brief training versus lip stimulation, of treatment with an NO donor versus saline, and of the combined stimuli producing long-term memory. Changes were examined in mRNA expression of Aplysia homologs of C/EBP, CREB1, CREB1α, CREB1β, and CREB2, in both the buccal and cerebral ganglia controlling feeding. Both the brief training and the NO donor increased expression of C/EBP, CREB1, CREB1α, and CREB1β, but not CREB2 in the buccal ganglia. For CREB1α, there was a significant interaction between the effects of the brief training and of the NO donor. In addition, the NO donor, but not brief training, increased expression of all of the genes in the cerebral ganglion. These findings show that the components of learning that alone do not produce memory produce molecular changes in different ganglia. Thus, long-term memory is likely to arise by both additive and interactive increases in gene expression.
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Affiliation(s)
- Valeria Briskin-Luchinsky
- The Mina and Everard Goodman Faculty of Life Sciences and The Leslie and Susan Gonda (Goldschmied) Multidisciplinary Brain Research Center, Bar Ilan University, Ramat Gan, 52900, Israel
| | - Roi Levy
- The Mina and Everard Goodman Faculty of Life Sciences and The Leslie and Susan Gonda (Goldschmied) Multidisciplinary Brain Research Center, Bar Ilan University, Ramat Gan, 52900, Israel
| | - Maayan Halfon
- The Mina and Everard Goodman Faculty of Life Sciences and The Leslie and Susan Gonda (Goldschmied) Multidisciplinary Brain Research Center, Bar Ilan University, Ramat Gan, 52900, Israel
| | - Abraham J Susswein
- The Mina and Everard Goodman Faculty of Life Sciences and The Leslie and Susan Gonda (Goldschmied) Multidisciplinary Brain Research Center, Bar Ilan University, Ramat Gan, 52900, Israel
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12
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Schaefer N, Rotermund C, Blumrich EM, Lourenco MV, Joshi P, Hegemann RU, Jamwal S, Ali N, García Romero EM, Sharma S, Ghosh S, Sinha JK, Loke H, Jain V, Lepeta K, Salamian A, Sharma M, Golpich M, Nawrotek K, Paidi RK, Shahidzadeh SM, Piermartiri T, Amini E, Pastor V, Wilson Y, Adeniyi PA, Datusalia AK, Vafadari B, Saini V, Suárez-Pozos E, Kushwah N, Fontanet P, Turner AJ. The malleable brain: plasticity of neural circuits and behavior - a review from students to students. J Neurochem 2017. [PMID: 28632905 DOI: 10.1111/jnc.14107] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
One of the most intriguing features of the brain is its ability to be malleable, allowing it to adapt continually to changes in the environment. Specific neuronal activity patterns drive long-lasting increases or decreases in the strength of synaptic connections, referred to as long-term potentiation and long-term depression, respectively. Such phenomena have been described in a variety of model organisms, which are used to study molecular, structural, and functional aspects of synaptic plasticity. This review originated from the first International Society for Neurochemistry (ISN) and Journal of Neurochemistry (JNC) Flagship School held in Alpbach, Austria (Sep 2016), and will use its curriculum and discussions as a framework to review some of the current knowledge in the field of synaptic plasticity. First, we describe the role of plasticity during development and the persistent changes of neural circuitry occurring when sensory input is altered during critical developmental stages. We then outline the signaling cascades resulting in the synthesis of new plasticity-related proteins, which ultimately enable sustained changes in synaptic strength. Going beyond the traditional understanding of synaptic plasticity conceptualized by long-term potentiation and long-term depression, we discuss system-wide modifications and recently unveiled homeostatic mechanisms, such as synaptic scaling. Finally, we describe the neural circuits and synaptic plasticity mechanisms driving associative memory and motor learning. Evidence summarized in this review provides a current view of synaptic plasticity in its various forms, offers new insights into the underlying mechanisms and behavioral relevance, and provides directions for future research in the field of synaptic plasticity. Read the Editorial Highlight for this article on page 788. Cover Image for this issue: doi: 10.1111/jnc.13815.
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Affiliation(s)
- Natascha Schaefer
- Institute for Clinical Neurobiology, Julius-Maximilians-University of Wuerzburg, Würzburg, Germany
| | - Carola Rotermund
- German Center of Neurodegenerative Diseases, University of Tuebingen, Tuebingen, Germany
| | - Eva-Maria Blumrich
- Centre for Biomolecular Interactions Bremen, Faculty 2 (Biology/Chemistry), University of Bremen, Bremen, Germany.,Centre for Environmental Research and Sustainable Technology, University of Bremen, Bremen, Germany
| | - Mychael V Lourenco
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Pooja Joshi
- Inserm UMR 1141, Robert Debre Hospital, Paris, France
| | - Regina U Hegemann
- Department of Psychology, Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Sumit Jamwal
- Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, India
| | - Nilufar Ali
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | | | - Sorabh Sharma
- Neuropharmacology Division, Department of Pharmacy, Birla Institute of Technology and Science, Pilani, Rajasthan, India
| | - Shampa Ghosh
- National Institute of Nutrition (NIN), Indian Council of Medical Research (ICMR), Tarnaka, Hyderabad, India
| | - Jitendra K Sinha
- National Institute of Nutrition (NIN), Indian Council of Medical Research (ICMR), Tarnaka, Hyderabad, India
| | - Hannah Loke
- Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Molecular and Translational Science, Monash University, Melbourne, Victoria, Australia
| | - Vishal Jain
- Defence Institute of Physiology and Allied Sciences, Delhi, India
| | - Katarzyna Lepeta
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Ahmad Salamian
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Mahima Sharma
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Mojtaba Golpich
- Department of Medicine, University Kebangsaan Malaysia Medical Centre (HUKM), Cheras, Kuala Lumpur, Malaysia
| | - Katarzyna Nawrotek
- Department of Process Thermodynamics, Faculty of Process and Environmental Engineering, Lodz University of Technology, Lodz, Poland
| | - Ramesh K Paidi
- CSIR-Indian Institute of Chemical Biology, Jadavpur, Kolkata, India
| | - Sheila M Shahidzadeh
- Department of Biology, Program in Neuroscience, Syracuse University, Syracuse, New York, USA
| | - Tetsade Piermartiri
- Programa de Pós-Graduação em Neurociências, Universidade Federal de Santa Catarina (UFSC), Florianópolis, Brazil
| | - Elham Amini
- Department of Medicine, University Kebangsaan Malaysia Medical Centre (HUKM), Cheras, Kuala Lumpur, Malaysia
| | - Veronica Pastor
- Instituto de Biología Celular y Neurociencia Prof. Eduardo De Robertis, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Yvette Wilson
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Philip A Adeniyi
- Cell Biology and Neurotoxicity Unit, Department of Anatomy, College of Medicine and Health Sciences, Afe Babalola University, Ado - Ekiti, Ekiti State, Nigeria
| | | | - Benham Vafadari
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Vedangana Saini
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Edna Suárez-Pozos
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Toxicología, México
| | - Neetu Kushwah
- Defence Institute of Physiology and Allied Sciences, Delhi, India
| | - Paula Fontanet
- Division of Molecular and Cellular Neuroscience, Institute of Cellular Biology and Neuroscience (IBCN), CONICET-UBA, School of Medicine, Buenos Aires, Argentina
| | - Anthony J Turner
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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13
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Lyons LC, Gardner JS, Gandour CE, Krishnan HC. Role of proteasome-dependent protein degradation in long-term operant memory in Aplysia. ACTA ACUST UNITED AC 2016; 24:59-64. [PMID: 27980077 PMCID: PMC5159658 DOI: 10.1101/lm.043794.116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Accepted: 10/24/2016] [Indexed: 01/26/2023]
Abstract
We investigated the in vivo role of protein degradation during intermediate (ITM) and long-term memory (LTM) in Aplysia using an operant learning paradigm. The proteasome inhibitor MG-132 inhibited the induction and molecular consolidation of LTM with no effect on ITM. Remarkably, maintenance of steady-state protein levels through inhibition of protein synthesis using either anisomycin or rapamycin in conjunction with proteasome inhibition permitted the formation of robust 24 h LTM. Our studies suggest a primary role for proteasomal activity in facilitation of gene transcription for LTM and raise the possibility that synaptic mechanisms are sufficient to sustain 24 h memory.
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Affiliation(s)
- Lisa C Lyons
- Department of Biological Science, Program in Neuroscience, Florida State University, Tallahassee, Florida 32306-4295, USA
| | - Jacob S Gardner
- Department of Biological Science, Program in Neuroscience, Florida State University, Tallahassee, Florida 32306-4295, USA
| | - Catherine E Gandour
- Department of Biological Science, Program in Neuroscience, Florida State University, Tallahassee, Florida 32306-4295, USA
| | - Harini C Krishnan
- Department of Biological Science, Program in Neuroscience, Florida State University, Tallahassee, Florida 32306-4295, USA
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14
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Krishnan HC, Gandour CE, Ramos JL, Wrinkle MC, Sanchez-Pacheco JJ, Lyons LC. Acute Sleep Deprivation Blocks Short- and Long-Term Operant Memory in Aplysia. Sleep 2016; 39:2161-2171. [PMID: 27748243 DOI: 10.5665/sleep.6320] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 08/08/2016] [Indexed: 01/11/2023] Open
Abstract
STUDY OBJECTIVES Insufficient sleep in individuals appears increasingly common due to the demands of modern work schedules and technology use. Consequently, there is a growing need to understand the interactions between sleep deprivation and memory. The current study determined the effects of acute sleep deprivation on short and long-term associative memory using the marine mollusk Aplysia californica, a relatively simple model system well known for studies of learning and memory. METHODS Aplysia were sleep deprived for 9 hours using context changes and tactile stimulation either prior to or after training for the operant learning paradigm, learning that food is inedible (LFI). The effects of sleep deprivation on short-term (STM) and long-term memory (LTM) were assessed. RESULTS Acute sleep deprivation prior to LFI training impaired the induction of STM and LTM with persistent effects lasting at least 24 h. Sleep deprivation immediately after training blocked the consolidation of LTM. However, sleep deprivation following the period of molecular consolidation did not affect memory recall. Memory impairments were independent of handling-induced stress, as daytime handled control animals demonstrated no memory deficits. Additional training immediately after sleep deprivation failed to rescue the induction of memory, but additional training alleviated the persistent impairment in memory induction when training occurred 24 h following sleep deprivation. CONCLUSIONS Acute sleep deprivation inhibited the induction and consolidation, but not the recall of memory. These behavioral studies establish Aplysia as an effective model system for studying the interactions between sleep and memory formation.
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Affiliation(s)
- Harini C Krishnan
- Department of Biological Science, Florida State University, Tallahassee, FL.,Program in Neuroscience, Florida State University, Tallahassee, FL
| | | | - Joshua L Ramos
- Department of Biological Science, Florida State University, Tallahassee, FL
| | - Mariah C Wrinkle
- Department of Biological Science, Florida State University, Tallahassee, FL
| | | | - Lisa C Lyons
- Department of Biological Science, Florida State University, Tallahassee, FL.,Program in Neuroscience, Florida State University, Tallahassee, FL
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15
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Differential role of calpain-dependent protein cleavage in intermediate and long-term operant memory in Aplysia. Neurobiol Learn Mem 2016; 137:134-141. [PMID: 27913293 DOI: 10.1016/j.nlm.2016.11.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 11/28/2016] [Accepted: 11/29/2016] [Indexed: 01/06/2023]
Abstract
In addition to protein synthesis, protein degradation or protein cleavage may be necessary for intermediate (ITM) and long-term memory (LTM) to remove molecular constraints, facilitate persistent kinase activity and modulate synaptic plasticity. Calpains, a family of conserved calcium dependent cysteine proteases, modulate synaptic function through protein cleavage. We used the marine mollusk Aplysia californica to investigate the in vivo role of calpains during intermediate and long-term operant memory formation using the learning that food is inedible (LFI) paradigm. A single LFI training session, in which the animal associates a specific netted seaweed with the failure to swallow, generates short (30min), intermediate (4-6h) and long-term (24h) memory. Using the calpain inhibitors calpeptin and MDL-28170, we found that ITM requires calpain activity for induction and consolidation similar to the previously reported requirements for persistent protein kinase C activity in intermediate-term LFI memory. The induction of LTM also required calpain activity. In contrast to ITM, calpain activity was not necessary for the molecular consolidation of LTM. Surprisingly, six hours after LFI training we found that calpain activity was necessary for LTM, although this is a time at which neither persistent PKC activity nor protein synthesis is required for the maintenance of long-term LFI memory. These results demonstrate that calpains function in multiple roles in vivo during associative memory formation.
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16
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Mirisis AA, Alexandrescu A, Carew TJ, Kopec AM. The Contribution of Spatial and Temporal Molecular Networks in the Induction of Long-term Memory and Its Underlying Synaptic Plasticity. AIMS Neurosci 2016; 3:356-384. [PMID: 27819030 PMCID: PMC5096789 DOI: 10.3934/neuroscience.2016.3.356] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ability to form long-lasting memories is critical to survival and thus is highly conserved across the animal kingdom. By virtue of its complexity, this same ability is vulnerable to disruption by a wide variety of neuronal traumas and pathologies. To identify effective therapies with which to treat memory disorders, it is critical to have a clear understanding of the cellular and molecular mechanisms which subserve normal learning and memory. A significant challenge to achieving this level of understanding is posed by the wide range of distinct temporal and spatial profiles of molecular signaling induced by learning-related stimuli. In this review we propose that a useful framework within which to address this challenge is to view the molecular foundation of long-lasting plasticity as composed of unique spatial and temporal molecular networks that mediate signaling both within neurons (such as via kinase signaling) as well as between neurons (such as via growth factor signaling). We propose that evaluating how cells integrate and interpret these concurrent and interacting molecular networks has the potential to significantly advance our understanding of the mechanisms underlying learning and memory formation.
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Affiliation(s)
- Anastasios A. Mirisis
- Center for Neural Science, New York University, New York, NY, USA
- Department of Biology, New York University, New York, NY, USA
| | - Anamaria Alexandrescu
- Center for Neural Science, New York University, New York, NY, USA
- Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA
| | - Thomas J. Carew
- Center for Neural Science, New York University, New York, NY, USA
| | - Ashley M. Kopec
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
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17
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Chronic sleep deprivation differentially affects short and long-term operant memory in Aplysia. Neurobiol Learn Mem 2016; 134 Pt B:349-59. [PMID: 27555235 DOI: 10.1016/j.nlm.2016.08.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/12/2016] [Accepted: 08/18/2016] [Indexed: 12/31/2022]
Abstract
The induction, formation and maintenance of memory represent dynamic processes modulated by multiple factors including the circadian clock and sleep. Chronic sleep restriction has become common in modern society due to occupational and social demands. Given the impact of cognitive impairments associated with sleep deprivation, there is a vital need for a simple animal model in which to study the interactions between chronic sleep deprivation and memory. We used the marine mollusk Aplysia californica, with its simple nervous system, nocturnal sleep pattern and well-characterized learning paradigms, to assess the effects of two chronic sleep restriction paradigms on short-term (STM) and long-term (LTM) associative memory. The effects of sleep deprivation on memory were evaluated using the operant learning paradigm, learning that food is inedible, in which the animal associates a specific netted seaweed with failed swallowing attempts. We found that two nights of 6h sleep deprivation occurring during the first or last half of the night inhibited both STM and LTM. Moreover, the impairment in STM persisted for more than 24h. A milder, prolonged sleep deprivation paradigm consisting of 3 consecutive nights of 4h sleep deprivation also blocked STM, but had no effect on LTM. These experiments highlight differences in the sensitivity of STM and LTM to chronic sleep deprivation. Moreover, these results establish Aplysia as a valid model for studying the interactions between chronic sleep deprivation and associative memory paving the way for future studies delineating the mechanisms through which sleep restriction affects memory formation.
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18
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Shobe J, Philips GT, Carew TJ. Transforming growth factor β recruits persistent MAPK signaling to regulate long-term memory consolidation in Aplysia californica. ACTA ACUST UNITED AC 2016; 23:182-8. [PMID: 27084925 PMCID: PMC4836639 DOI: 10.1101/lm.040915.115] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 02/08/2016] [Indexed: 12/25/2022]
Abstract
In this study, we explore the mechanistic relationship between growth factor signaling and kinase activity that supports the protein synthesis-dependent phase of long-term memory (LTM) consolidation for sensitization of Aplysia. Specifically, we examine LTM for tail shock-induced sensitization of the tail-elicited siphon withdrawal (T-SW) reflex, a form of memory that requires both (i) extracellular signal-regulated kinase (ERK1/2; MAPK) activity within identified sensory neurons (SNs) that mediate the T-SW and (ii) the activation of transforming growth factor β (TGFβ) signaling. We now report that repeated tail shocks that induce intermediate-term (ITM) and LTM for sensitization, also induce a sustained post-training phase of MAPK activity in SNs (lasting at least 1 h). We identified two mechanistically distinct phases of post-training MAPK: (i) an immediate phase that does not require ongoing protein synthesis or TGFβ signaling, and (ii) a sustained phase that requires both protein synthesis and extracellular TGFβ signaling. We find that LTM consolidation requires sustained MAPK, and is disrupted by inhibitors of protein synthesis and TGFβ signaling during the consolidation window. These results provide strong evidence that TGFβ signaling sustains MAPK activity as an essential mechanistic step for LTM consolidation.
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Affiliation(s)
- Justin Shobe
- Department of Neurobiology, University of California at Los Angeles, Los Angeles, California 90095, USA
| | - Gary T Philips
- Center for Neural Science, New York University, New York, New York 10003, USA
| | - Thomas J Carew
- Center for Neural Science, New York University, New York, New York 10003, USA
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19
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Krishnan HC, Lyons LC. Synchrony and desynchrony in circadian clocks: impacts on learning and memory. ACTA ACUST UNITED AC 2015; 22:426-37. [PMID: 26286653 PMCID: PMC4561405 DOI: 10.1101/lm.038877.115] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 06/29/2015] [Indexed: 12/11/2022]
Abstract
Circadian clocks evolved under conditions of environmental variation, primarily alternating light dark cycles, to enable organisms to anticipate daily environmental events and coordinate metabolic, physiological, and behavioral activities. However, modern lifestyle and advances in technology have increased the percentage of individuals working in phases misaligned with natural circadian activity rhythms. Endogenous circadian oscillators modulate alertness, the acquisition of learning, memory formation, and the recall of memory with examples of circadian modulation of memory observed across phyla from invertebrates to humans. Cognitive performance and memory are significantly diminished when occurring out of phase with natural circadian rhythms. Disruptions in circadian regulation can lead to impairment in the formation of memories and manifestation of other cognitive deficits. This review explores the types of interactions through which the circadian clock modulates cognition, highlights recent progress in identifying mechanistic interactions between the circadian system and the processes involved in memory formation, and outlines methods used to remediate circadian perturbations and reinforce circadian adaptation.
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Affiliation(s)
- Harini C Krishnan
- Department of Biological Science, Program in Neuroscience, Florida State University, Tallahassee, Florida 32306, USA
| | - Lisa C Lyons
- Department of Biological Science, Program in Neuroscience, Florida State University, Tallahassee, Florida 32306, USA
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20
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Ma H, Butler MR, Thapa A, Belcher J, Yang F, Baehr W, Biel M, Michalakis S, Ding XQ. cGMP/Protein Kinase G Signaling Suppresses Inositol 1,4,5-Trisphosphate Receptor Phosphorylation and Promotes Endoplasmic Reticulum Stress in Photoreceptors of Cyclic Nucleotide-gated Channel-deficient Mice. J Biol Chem 2015; 290:20880-20892. [PMID: 26124274 DOI: 10.1074/jbc.m115.641159] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Indexed: 11/06/2022] Open
Abstract
Photoreceptor cyclic nucleotide-gated (CNG) channels play a pivotal role in phototransduction. Mutations in the cone CNG channel subunits CNGA3 and CNGB3 are associated with achromatopsia and cone dystrophies. We have shown endoplasmic reticulum (ER) stress-associated apoptotic cone death and increased phosphorylation of the ER Ca(2+) channel inositol 1,4,5-trisphosphate receptor 1 (IP3R1) in CNG channel-deficient mice. We also presented a remarkable elevation of cGMP and an increased activity of the cGMP-dependent protein kinase (protein kinase G, PKG) in CNG channel deficiency. This work investigated whether cGMP/PKG signaling regulates ER stress and IP3R1 phosphorylation in CNG channel-deficient cones. Treatment with PKG inhibitor and deletion of guanylate cyclase-1 (GC1), the enzyme producing cGMP in cones, were used to suppress cGMP/PKG signaling in cone-dominant Cnga3(-/-)/Nrl(-/-) mice. We found that treatment with PKG inhibitor or deletion of GC1 effectively reduced apoptotic cone death, increased expression levels of cone proteins, and decreased activation of Müller glial cells. Furthermore, we observed significantly increased phosphorylation of IP3R1 and reduced ER stress. Our findings demonstrate a role of cGMP/PKG signaling in ER stress and ER Ca(2+) channel regulation and provide insights into the mechanism of cone degeneration in CNG channel deficiency.
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Affiliation(s)
- Hongwei Ma
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Michael R Butler
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Arjun Thapa
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Josh Belcher
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Fan Yang
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Wolfgang Baehr
- John A. Moran Eye Center, University of Utah, Salt Lake City, Utah 84132
| | - Martin Biel
- Center for Integrated Protein Science Munich and Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Stylianos Michalakis
- Center for Integrated Protein Science Munich and Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Xi-Qin Ding
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104.
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21
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Kopec AM, Carew TJ. Growth factor signaling and memory formation: temporal and spatial integration of a molecular network. Learn Mem 2013; 20:531-9. [PMID: 24042849 PMCID: PMC3768197 DOI: 10.1101/lm.031377.113] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Growth factor (GF) signaling is critically important for developmental plasticity. It also plays a crucial role in adult plasticity, such as that required for memory formation. Although different GFs interact with receptors containing distinct types of kinase domains, they typically signal through converging intracellular cascades (e.g., Ras–MEK–MAPK) to mediate overlapping functional endpoints. Several GFs have been implicated in memory formation, but due to a high level of convergent signaling, the unique contributions of individual GFs as well as the interactions between GF signaling cascades during the induction of memory is not well known. In this review, we highlight the unique roles of specific GFs in dendritic plasticity, and discuss the spatial and temporal profiles of different GFs during memory formation. Collectively, the data suggest that the roles of GF signaling in long-lasting behavioral and structural plasticity may be best viewed as interactive components in a complex molecular network.
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Affiliation(s)
- Ashley M Kopec
- Center for Neural Science, New York University, New York, New York 10003, USA
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22
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PKC-epsilon activation is required for recognition memory in the rat. Behav Brain Res 2013; 253:280-9. [PMID: 23911427 DOI: 10.1016/j.bbr.2013.07.036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 07/18/2013] [Accepted: 07/22/2013] [Indexed: 11/20/2022]
Abstract
Activation of PKCɛ, an abundant and developmentally regulated PKC isoform in the brain, has been implicated in memory throughout life and across species. Yet, direct evidence for a mechanistic role for PKCɛ in memory is still lacking. Hence, we sought to evaluate this in rats, using short-term treatments with two PKCɛ-selective peptides, the inhibitory ɛV1-2 and the activating ψɛRACK, and the novel object recognition task (NORT). Our results show that the PKCɛ-selective activator ψɛRACK, did not have a significant effect on recognition memory. In the short time frames used, however, inhibition of PKCɛ activation with the peptide inhibitor ɛV1-2 significantly impaired recognition memory. Moreover, when we addressed at the molecular level the immediate proximal signalling events of PKCɛ activation in acutely dissected rat hippocampi, we found that ψɛRACK increased in a time-dependent manner phosphorylation of MARCKS and activation of Src, Raf, and finally ERK1/2, whereas ɛV1-2 inhibited all basal activity of this pathway. Taken together, these findings present the first direct evidence that PKCɛ activation is an essential molecular component of recognition memory and point toward the use of systemically administered PKCɛ-regulating peptides as memory study tools and putative therapeutic agents.
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23
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Nitric oxide synthesis and cGMP production is important for neurite growth and synapse remodeling after axotomy. J Neurosci 2013; 33:5626-37. [PMID: 23536077 DOI: 10.1523/jneurosci.3659-12.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Nitric oxide (NO) is an important signaling molecule with a variety of functions in the CNS, including a potential role in modulating neuronal growth and synapse formation. In the present study, we used tractable, identified neurons in the CNS of the pond snail Lymnaea stagnalis to study the role of endogenous NO signaling in neuronal growth and synaptic remodeling after nerve injury. Axonal damage of L. stagnalis neurons B1 and B2 induces extensive central growth of neurites that is accompanied by changes in existing electrical connections, the transient formation of novel electrical connections, and the formation of a novel excitatory chemical synapse from B2 to B1 neurons. Partial chronic inhibition of endogenous NO synthesis reduces neurite growth in NO-synthase-expressing B2, but has only minor effects on NOS-negative B1 neurons. Chronic application of an NO donor while inhibiting endogenous NO synthesis rescues neurite extension in B2 neurons and boosts growth of B1 neurons. Blocking soluble guanylate cyclase activity completely suppresses neurite extension and synaptic remodeling after nerve crush, demonstrating the importance of cGMP in these processes. Interestingly, inhibition of cGMP-dependent protein kinase only suppresses chemical synapse formation without effects on neuronal growth and electrical synapse remodeling. We conclude that NO signaling via cGMP is an important modulator of both neurite growth and synaptic remodeling after nerve crush. However, differential effects of cGMP-dependent protein kinase inhibition on neurite growth and synaptic remodeling suggest that these effects are mediated by separate signaling pathways.
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24
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Protein phosphatase-dependent circadian regulation of intermediate-term associative memory. J Neurosci 2013; 33:4605-13. [PMID: 23467376 DOI: 10.1523/jneurosci.4534-12.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The endogenous circadian clock is a principal factor modulating memory across species. Determining the processes through which the circadian clock modulates memory formation is a key issue in understanding and identifying mechanisms to improve memory. We used the marine mollusk Aplysia californica to investigate circadian modulation of intermediate-term memory (ITM) and the mechanisms through which the circadian clock phase specifically suppresses memory using the operant learning paradigm, learning that food is inedible. We found that ITM, a temporally and mechanistically distinct form of memory, is rhythmically expressed under light-dark and constant conditions when induced by either massed or spaced training. Strong circadian regulation of ITM occurs with memory exhibited only by animals trained during the early subjective day; no apparent memory is expressed when training occurs during the late subjective day or night. Given the necessity of multiple persistent kinase cascades for ITM, we investigated whether protein phosphatase activity affected circadian modulation. Inhibition of protein phosphatases 1 and 2A blocked ITM when animals were trained during the early (subjective) day while resulting in phase-specific memory rescue when animals were trained late in the subjective day and early night. In contrast, inhibition of calcineurin did not block ITM when animals were trained during the early day and permitted ITM when animals were trained during the late subjective day, early evening, and throughout the night. These results demonstrate that levels of protein phosphatase activity are critical regulators of ITM and one mechanism through which the circadian clock regulates memory formation.
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25
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Philips GT, Ye X, Kopec AM, Carew TJ. MAPK establishes a molecular context that defines effective training patterns for long-term memory formation. J Neurosci 2013; 33:7565-73. [PMID: 23616561 PMCID: PMC3865502 DOI: 10.1523/jneurosci.5561-12.2013] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 03/19/2013] [Accepted: 03/20/2013] [Indexed: 12/23/2022] Open
Abstract
Although the importance of spaced training trials in the formation of long-term memory (LTM) is widely appreciated, surprisingly little is known about the molecular mechanisms that support interactions between individual trials. The intertrial dynamics of ERK/MAPK activation have recently been correlated with effective training patterns for LTM. However, whether and how MAPK is required to mediate intertrial interactions remains unknown. Using a novel two-trial training pattern which induces LTM in Aplysia, we show that the first of two training trials recruits delayed protein synthesis-dependent nuclear MAPK activity that establishes a unique molecular context involving the recruitment of CREB kinase and ApC/EBP and is an essential intertrial signaling mechanism for LTM induction. These findings provide the first demonstration of a requirement for MAPK in the intertrial interactions during memory formation and suggest that the kinetics of MAPK activation following individual experiences determines effective training intervals for LTM formation.
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Affiliation(s)
- Gary T. Philips
- Center for Neural Science, New York University, New York, New York 10003
| | - Xiaojing Ye
- Center for Neural Science, New York University, New York, New York 10003
| | - Ashley M. Kopec
- Center for Neural Science, New York University, New York, New York 10003
| | - Thomas J. Carew
- Center for Neural Science, New York University, New York, New York 10003
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26
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Involvement of insulin-like peptide in long-term synaptic plasticity and long-term memory of the pond snail Lymnaea stagnalis. J Neurosci 2013; 33:371-83. [PMID: 23283349 DOI: 10.1523/jneurosci.0679-12.2013] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The pond snail Lymnaea stagnalis is capable of learning taste aversion and consolidating this learning into long-term memory (LTM) that is called conditioned taste aversion (CTA). Previous studies showed that some molluscan insulin-related peptides (MIPs) were upregulated in snails exhibiting CTA. We thus hypothesized that MIPs play an important role in neurons underlying the CTA-LTM consolidation process. To examine this hypothesis, we first observed the distribution of MIP II, a major peptide of MIPs, and MIP receptor and determined the amounts of their mRNAs in the CNS. MIP II was only observed in the light green cells in the cerebral ganglia, but the MIP receptor was distributed throughout the entire CNS, including the buccal ganglia. Next, when we applied exogenous mammalian insulin, secretions from MIP-containing cells or partially purified MIPs, to the isolated CNS, we observed a long-term change in synaptic efficacy (i.e., enhancement) of the synaptic connection between the cerebral giant cell (a key interneuron for CTA) and the B1 motor neuron (a buccal motor neuron). This synaptic enhancement was blocked by application of an insulin receptor antibody to the isolated CNS. Finally, injection of the insulin receptor antibody into the snail before CTA training, while not blocking the acquisition of taste aversion learning, blocked the memory consolidation process; thus, LTM was not observed. These data suggest that MIPs trigger changes in synaptic connectivity that may be correlated with the consolidation of taste aversion learning into CTA-LTM in the Lymnaea CNS.
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27
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Maharana C, Sharma KP, Sharma SK. Feedback mechanism in depolarization-induced sustained activation of extracellular signal-regulated kinase in the hippocampus. Sci Rep 2013; 3:1103. [PMID: 23346360 PMCID: PMC3551232 DOI: 10.1038/srep01103] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 12/10/2012] [Indexed: 11/20/2022] Open
Abstract
Phosphorylation plays important roles in several processes including synaptic plasticity and memory. The critical role of extracellular signal-regulated kinase (ERK) in these processes is well established. ERK is activated in a sustained manner by different stimuli. However, the mechanisms of sustained ERK activation are not completely understood. Here we show that KCl depolarization-induced sustained ERK activation in the hippocampal slices is critically dependent on protein synthesis and transcription. In addition, the sustained ERK activation requires receptor tyrosine kinase(s) activity. In support of a role for a growth factor in sustained ERK activation, KCl depolarization enhances the level of brain-derived neurotrophic factor (BDNF). Furthermore, BDNF antibody blocks KCl-induced sustained ERK activation. These results suggest a positive feed-back loop in which depolarization-induced BDNF maintains ERK activation in the sustained phase.
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Levitan D, Saada-Madar R, Teplinsky A, Susswein AJ. Localization of molecular correlates of memory consolidation to buccal ganglia mechanoafferent neurons after learning that food is inedible in Aplysia. Learn Mem 2012; 19:503-12. [DOI: 10.1101/lm.026393.112] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Birner-Gruenberger R, Darnhofer B, Chen WQ, Monje FJ, Lubec G. Proteomic characterization of the abdominal ganglion of Aplysia californica-a protein resource for neuroscience. Proteomics 2012; 12:2482-6. [PMID: 22696492 DOI: 10.1002/pmic.201100641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 01/09/2012] [Accepted: 01/25/2012] [Indexed: 11/08/2022]
Abstract
Aplysia californica (AC) is a widely used model for testing learning and memory. Although ESTs have been generated, proteomics studies on AC proteins are limited. Studies at the protein level, however, are mandatory, not only due to the fact that studies at the nucleic acid level are not allowing conclusions about PTMs. A gel-based proteomics method was therefore applied to carry out protein profiling in abdominal ganglia from AC. Abdominal ganglia were extirpated, proteins extracted and run on 2DE with subsequent in-gel digestion with trypsin, chymotrypsin, and partially by subtilisin. Peptides were identified using a nano-LC-ESI-LTQ-FT-mass spectrometer. MS/MS data were analyzed by searching the NCBI nonredundant public AC EST database and the NCBI nonredundant public AC protein database. A total of 477 different proteins represented by 363 protein spots were detected and were assigned to different protein pathways as for instance signaling (receptors, protein kinases, and phosphatases), metabolism, protein synthesis, handling and degradation, cytoskeleton and structural, oxido-redox, heat shock and chaperone, hypothetical, predicted and unnamed proteins. The generation of a protein map of soluble proteins shows the existence of so far hypothetical and predicted proteins and is allowing and challenging further work at the protein level, in particular in the field of neuroscience.
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Affiliation(s)
- Ruth Birner-Gruenberger
- Proteomics Core Facility, Center for Medical Research and Institute of Pathology, Medical University of Graz, Austria
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Massed training-induced intermediate-term operant memory in aplysia requires protein synthesis and multiple persistent kinase cascades. J Neurosci 2012; 32:4581-91. [PMID: 22457504 DOI: 10.1523/jneurosci.6264-11.2012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The Aplysia feeding system with its high degree of plasticity and well characterized neuronal circuitry is well suited for investigations of memory formation. We used an operant paradigm, learning that food is inedible (LFI), to investigate the signaling pathways underlying intermediate-term memory (ITM) in Aplysia. During a single massed training session, the animal associates a specific seaweed with the failure to swallow, generating short-term (30 min) and long-term (24 h) memory. We investigated whether the same training protocol induced the formation of ITM. We found that massed LFI training resulted in temporally distinct protein synthesis-dependent memory evident 4-6 h after training. Through in vivo experiments, we determined that the formation of ITM required protein kinase A, protein kinase C, and MAPK. Moreover, the maintenance of ITM required PKA, PKM Apl III, and MAPK because inhibition of any of these kinases after training or before testing blocked the expression of memory. In contrast, additional experiments determined that the maintenance of long-term memory appeared independent of PKM Apl III. Using Western blotting, we found that sustained MAPK phosphorylation was dependent upon protein synthesis, but not PKA or PKC activity. Thus, massed training-induced intermediate-term operant memory requires protein synthesis as well as persistent or sustained kinase signaling for PKA, PKC, and MAPK. While short-, intermediate-, and long-term memory are induced by the same training protocol, considerable differences exist in both the combination and timing of signaling cascades that induce the formation and maintenance of these temporally distinct memories.
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Lantz CL, Wang W, Medina AE. Early alcohol exposure disrupts visual cortex plasticity in mice. Int J Dev Neurosci 2012; 30:351-7. [PMID: 22617459 DOI: 10.1016/j.ijdevneu.2012.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 04/20/2012] [Accepted: 05/05/2012] [Indexed: 12/30/2022] Open
Abstract
There is growing evidence that deficits in neuronal plasticity underlie the cognitive problems seen in fetal alcohol spectrum disorders (FASD). However, the mechanisms behind these deficits are not clear. Here we test the effects of early alcohol exposure on ocular dominance plasticity (ODP) in mice and the reversibility of these effects by phosphodiesterase (PDE) inhibitors. Mouse pups were exposed to 5 g/kg of 25% ethanol i.p. on postnatal days (P) 5, 7 and 9. This type of alcohol exposure mimics binge drinking during the third trimester equivalent of human gestation. To assess ocular dominance plasticity animals were monocularly deprived at P21 for 10 days, and tested using optical imaging of intrinsic signals. During the period of monocular deprivation animals were treated with vinpocetine (20mg/kg; PDE1 inhibitor), rolipram (1.25mg/kg; PDE4 inhibitor), vardenafil (3mg/kg; PDE5 inhibitor) or vehicle solution. Monocular deprivation resulted in the expected shift in ocular dominance of the binocular zone in saline controls but not in the ethanol group. While vinpocetine successfully restored ODP in the ethanol group, rolipram and vardenafil did not. However, when rolipram and vardenafil were given simultaneously ODP was restored. PDE4 and PDE5 are specific to cAMP and cGMP respectively, while PDE1 acts on both of these nucleotides. Our findings suggest that the combined activation of the cAMP and cGMP cascades may be a good approach to improve neuronal plasticity in FASD models.
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Affiliation(s)
- Crystal L Lantz
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, United States
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Nitric oxide as a regulator of behavior: new ideas from Aplysia feeding. Prog Neurobiol 2012; 97:304-17. [PMID: 22575157 DOI: 10.1016/j.pneurobio.2012.03.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 12/28/2011] [Accepted: 03/12/2012] [Indexed: 12/29/2022]
Abstract
Nitric oxide (NO) regulates Aplysia feeding by novel mechanisms, suggesting new roles for NO in controlling the behavior of higher animals. In Aplysia, (1) NO helps maintain arousal when produced by neurons responding to attempts to swallow food; (2) NO biases the motor system to reject and reposition food that resists swallowing; (3) if mechanically resistant food is not successfully swallowed, NO mediates the formation and expression of memories of food inedibility; (4) NO production at rest inhibits feeding, countering the effects of food stimuli exciting feeding. At a cellular level, NO-dependent channels contribute to the resting potential of neurons controlling food finding and food consumption. Increases in L-arginine after animals eat act as a post-feeding inhibitory signal, presumably by modulating NO production at rest. NO also signals non-feeding behaviors that are associated with feeding inhibition. Thus, depending on context, NO may enhance or inhibit feeding behavior. The different functions of NO may reflect the evolution of NO signaling from a response to tissue damage that was then elaborated and used for additional functions. These results suggest that in higher animals (1) elicited and background transmitter release may have similar effects; (2) NO may be produced by neurons without firing, influencing adjacent neurons; (3) background NO production may contribute to a neuron's resting potential; (4) circulating factors affecting background NO production may regulate spatially separated neurons; (5) L-arginine can be used to regulate neural activity; (6) L-arginine may be an effective post-ingestion metabolic signal to regulate feeding.
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Lyons LC. Critical role of the circadian clock in memory formation: lessons from Aplysia. Front Mol Neurosci 2011; 4:52. [PMID: 22164133 PMCID: PMC3230803 DOI: 10.3389/fnmol.2011.00052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 11/24/2011] [Indexed: 11/13/2022] Open
Abstract
Unraveling the complexities of learning and the formation of memory requires identification of the cellular and molecular processes through which neural plasticity arises as well as recognition of the conditions or factors through which those processes are modulated. With its relatively simple nervous system, the marine mollusk Aplysia californica has proven an outstanding model system for studies of memory formation and identification of the molecular mechanisms underlying learned behaviors, including classical and operant associative learning paradigms and non-associative behaviors. In vivo behavioral studies in Aplysia have significantly furthered our understanding of how the endogenous circadian clock modulates memory formation. Sensitization of the tail-siphon withdrawal reflex represents a defensive non-associative learned behavior for which the circadian clock strongly modulates intermediate and long-term memory formation. Likewise, Aplysia exhibit circadian rhythms in long-term memory, but not short-term memory, for an operant associative learning paradigm. This review focuses on circadian modulation of intermediate and long-term memory and the putative mechanisms through which this modulation occurs. Additionally, potential functions and the adaptive advantages of time of day pressure on memory formation are considered. The influence of the circadian clock on learning and memory crosses distant phylogeny highlighting the evolutionary importance of the circadian clock on metabolic, physiological, and behavioral processes. Thus, studies in a simple invertebrate model system have and will continue to provide critical mechanistic insights to complementary processes in higher organisms.
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Affiliation(s)
- Lisa C Lyons
- Department of Biological Science, Program in Neuroscience, Florida State University , Tallahassee, FL, USA
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