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Tsokas P, Hsieh C, Flores-Obando RE, Bernabo M, Tcherepanov A, Hernández AI, Thomas C, Bergold PJ, Cottrell JE, Kremerskothen J, Shouval HZ, Nader K, Fenton AA, Sacktor TC. KIBRA anchoring the action of PKMζ maintains the persistence of memory. SCIENCE ADVANCES 2024; 10:eadl0030. [PMID: 38924398 PMCID: PMC11204205 DOI: 10.1126/sciadv.adl0030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 05/23/2024] [Indexed: 06/28/2024]
Abstract
How can short-lived molecules selectively maintain the potentiation of activated synapses to sustain long-term memory? Here, we find kidney and brain expressed adaptor protein (KIBRA), a postsynaptic scaffolding protein genetically linked to human memory performance, complexes with protein kinase Mzeta (PKMζ), anchoring the kinase's potentiating action to maintain late-phase long-term potentiation (late-LTP) at activated synapses. Two structurally distinct antagonists of KIBRA-PKMζ dimerization disrupt established late-LTP and long-term spatial memory, yet neither measurably affects basal synaptic transmission. Neither antagonist affects PKMζ-independent LTP or memory that are maintained by compensating PKCs in ζ-knockout mice; thus, both agents require PKMζ for their effect. KIBRA-PKMζ complexes maintain 1-month-old memory despite PKMζ turnover. Therefore, it is not PKMζ alone, nor KIBRA alone, but the continual interaction between the two that maintains late-LTP and long-term memory.
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Affiliation(s)
- Panayiotis Tsokas
- Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, NY 11203, USA
- Department of Anesthesiology, State University of New York Downstate Health Sciences University, Brooklyn, NY 11203, USA
| | - Changchi Hsieh
- Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, NY 11203, USA
| | - Rafael E. Flores-Obando
- Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, NY 11203, USA
| | - Matteo Bernabo
- Department of Psychology, McGill University, Montreal, Quebec H3A 1G1, Canada
| | - Andrew Tcherepanov
- Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, NY 11203, USA
| | - A. Iván Hernández
- Department of Pathology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, NY 11203, USA
| | - Christian Thomas
- Internal Medicine D (MedD), Department of Molecular Nephrology, University Hospital of Münster, 48149 Münster, Germany
| | - Peter J. Bergold
- Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, NY 11203, USA
| | - James E. Cottrell
- Department of Anesthesiology, State University of New York Downstate Health Sciences University, Brooklyn, NY 11203, USA
| | - Joachim Kremerskothen
- Internal Medicine D (MedD), Department of Molecular Nephrology, University Hospital of Münster, 48149 Münster, Germany
| | - Harel Z. Shouval
- Department of Neurobiology and Anatomy, University of Texas Medical at Houston, Houston, TX 77030, USA
| | - Karim Nader
- Department of Psychology, McGill University, Montreal, Quebec H3A 1G1, Canada
| | - André A. Fenton
- Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, NY 11203, USA
- Center for Neural Science, New York University, New York, NY 10003, USA
- Neuroscience Institute at NYU Langone Medical Center, New York, NY 10016, USA
| | - Todd C. Sacktor
- Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, NY 11203, USA
- Department of Anesthesiology, State University of New York Downstate Health Sciences University, Brooklyn, NY 11203, USA
- Department of Neurology, State University of New York Downstate Health Sciences University, Brooklyn, NY 11203, USA
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2
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Zhang H, Hu S, Yang P, Long H, Ma Q, Yin D, Xu G. HDAC9-mediated calmodulin deacetylation induces memory impairment in Alzheimer's disease. CNS Neurosci Ther 2024; 30:e14573. [PMID: 38421101 PMCID: PMC10850929 DOI: 10.1111/cns.14573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 11/20/2023] [Accepted: 12/04/2023] [Indexed: 03/02/2024] Open
Abstract
AIMS Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive cognitive dysfunction and memory impairment. AD pathology involves protein acetylation. Previous studies have mainly focused on histone acetylation in AD, however, the roles of nonhistone acetylation in AD are less explored. METHODS The protein acetylation and expression levels were detected by western blotting and co-immunoprecipitation. The stoichiometry of acetylation was measured by home-made and site-specific antibodies against acetylated-CaM (Ac-CaM) at K22, K95, and K116. Hippocampus-dependent learning and memory were evaluated by using the Morris water maze, novel object recognition, and contextual fear conditioning tests. RESULTS We showed that calmodulin (CaM) acetylation is reduced in plasma of AD patients and mice. CaM acetylation and its target Ca2+ /CaM-dependent kinase II α (CaMKIIα) activity were severely impaired in AD mouse brain. The stoichiometry showed that Ac-K22, K95-CaM acetylation were decreased in AD patients and mice. Moreover, we screened and identified that lysine deacetylase 9 (HDAC9) was the main deacetylase for CaM. In addition, HDAC9 inhibition increased CaM acetylation and CaMKIIα activity, and hippocampus-dependent memory in AD mice. CONCLUSIONS HDAC9-mediated CaM deacetylation induces memory impairment in AD, HDAC9, or CaM acetylation may become potential therapeutic targets for AD.
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Affiliation(s)
- Hai‐Long Zhang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of NeuroscienceSuzhou Medical College of Soochow University, Medical Center of Soochow UniversitySuzhouChina
| | - Shufen Hu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of NeuroscienceSuzhou Medical College of Soochow University, Medical Center of Soochow UniversitySuzhouChina
| | - Pin Yang
- Key Laboratory of Brain Functional Genomics, Ministry of Education and Shanghai, School of Life ScienceEast China Normal UniversityShanghaiChina
| | - Han‐Chun Long
- Department of NeurologyThe Affiliated Xingyi City Hospital of Guizhou Medical UniversityXingyiChina
| | - Quan‐Hong Ma
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of NeuroscienceSuzhou Medical College of Soochow University, Medical Center of Soochow UniversitySuzhouChina
| | - Dong‐Min Yin
- Key Laboratory of Brain Functional Genomics, Ministry of Education and Shanghai, School of Life ScienceEast China Normal UniversityShanghaiChina
| | - Guang‐Yin Xu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of NeuroscienceSuzhou Medical College of Soochow University, Medical Center of Soochow UniversitySuzhouChina
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3
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Zhang XO, Zhang Y, Cho CE, Engelke DS, Smolen P, Byrne JH, Do-Monte FH. Enhancing Associative Learning in Rats With a Computationally Designed Training Protocol. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2024; 4:165-181. [PMID: 38298784 PMCID: PMC10829654 DOI: 10.1016/j.bpsgos.2023.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 06/30/2023] [Accepted: 07/20/2023] [Indexed: 02/02/2024] Open
Abstract
Background Learning requires the activation of protein kinases with distinct temporal dynamics. In Aplysia, nonassociative learning can be enhanced by a computationally designed learning protocol with intertrial intervals (ITIs) that maximize the interaction between fast-activated PKA (protein kinase A) and slow-activated ERK (extracellular signal-regulated kinase). Whether a similar strategy can enhance associative learning in mammals is unknown. Methods We simulated 1000 training protocols with varying ITIs to predict an optimal protocol based on empirical data for PKA and ERK dynamics in rat hippocampus. Adult male rats received the optimal protocol or control protocols in auditory fear conditioning and fear extinction experiments. Immunohistochemistry was performed to evaluate pCREB (phosphorylated cAMP response element binding)\protein levels in brain regions that have been implicated in fear acquisition. Results Rats exposed to the optimal conditioning protocol with irregular ITIs exhibited impaired extinction memory acquisition within the session using a standard footshock intensity, and stronger fear memory retrieval and spontaneous recovery with a weaker footshock intensity, compared with rats that received massed or spaced conditioning protocols with fixed ITIs. Rats exposed to the optimal extinction protocol displayed improved extinction of contextual fear memory and reduced spontaneous recovery compared with rats that received standard extinction protocols. Moreover, the optimal conditioning protocol increased pCREB levels in the dentate gyrus of the dorsal hippocampus, suggesting enhanced induction of long-term potentiation. Conclusions These findings demonstrate that a computational model-driven behavioral intervention can enhance associative learning in mammals and may provide insight into strategies to improve cognition in humans.
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Affiliation(s)
- Xu O. Zhang
- Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas
| | - Yili Zhang
- Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas
| | - Claire E. Cho
- Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas
| | - Douglas S. Engelke
- Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas
| | - Paul Smolen
- Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas
| | - John H. Byrne
- Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas
| | - Fabricio H. Do-Monte
- Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, Texas
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4
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Machado Batista Sohn J, Cardoso NC, Raymundi AM, Prickaerts J, Stern CAJ. Phosphodiesterase 4 inhibition after retrieval switches the memory fate favoring extinction instead of reconsolidation. Sci Rep 2023; 13:20384. [PMID: 37990053 PMCID: PMC10663466 DOI: 10.1038/s41598-023-47717-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/17/2023] [Indexed: 11/23/2023] Open
Abstract
Phosphodiesterase 4 (PDE4), an enzyme expressed in the dorsal hippocampus (DH), hydrolyzes the cAMP, limiting the PKA-induced CREB phosphorylation (pCREB) and BDNF expression. Depending on the brain region, PKA and pCREB mediate reconsolidation or extinction, whereas BDNF is mainly related to extinction facilitation. The mechanisms underpinning the switch between reconsolidation and extinction are relatively unknown. Here, we tested the hypothesis that PDE4 might control these processes. We showed in Wistar rats submitted to contextual fear conditioning that PDE4 inhibition with roflumilast (ROF) within the DH, after a short retrieval, did not change freezing behavior after one day (TestA1). After 10 days, the ROF-treated group significantly reduced the expression of freezing behavior. This effect depended on retrieval, Test A1 exposure, and reinstated after a remainder foot shock, suggesting an extinction facilitation. The ROF effect depended on PKA after retrieval or, protein synthesis after Test A1. After retrieval, ROF treatment did not change the pCREB/CREB ratio in the DH. It enhanced proBDNF expression without changing pre-proBDNF or mature BDNF in the DH after Test A1. The results suggest that the inhibition of PDE4 in the DH after a short retrieval changes the memory sensibility from reconsolidation to extinction via regulating proBDNF expression.
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Affiliation(s)
- Jeferson Machado Batista Sohn
- Department of Pharmacology, Federal University of Parana, Curitiba, PR, Brazil
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, University of Maastricht, Maastricht, The Netherlands
| | | | - Ana Maria Raymundi
- Department of Pharmacology, Federal University of Parana, Curitiba, PR, Brazil
| | - Jos Prickaerts
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, University of Maastricht, Maastricht, The Netherlands
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5
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Kauwe G, Pareja-Navarro KA, Yao L, Chen JH, Wong I, Saloner R, Cifuentes H, Nana AL, Shah S, Li Y, Le D, Spina S, Grinberg LT, Seeley WW, Kramer JH, Sacktor TC, Schilling B, Gan L, Casaletto KB, Tracy TE. KIBRA repairs synaptic plasticity and promotes resilience to tauopathy-related memory loss. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.12.543777. [PMID: 37398236 PMCID: PMC10312627 DOI: 10.1101/2023.06.12.543777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Synaptic plasticity is obstructed by pathogenic tau in the brain, representing a key mechanism that underlies memory loss in Alzheimer's disease (AD) and related tauopathies. Here, we define a mechanism for plasticity repair in vulnerable neurons using the C-terminus of the KIdney/BRAin (KIBRA) protein (CT-KIBRA). We show that CT-KIBRA restores plasticity and memory in transgenic mice expressing pathogenic human tau; however, CT-KIBRA did not alter tau levels or prevent tau-induced synapse loss. Instead, we find that CT-KIBRA binds to and stabilizes protein kinase Mζ (PKMζ) to maintain synaptic plasticity and memory despite tau-mediated pathogenesis. In humans we find that reduced KIBRA in brain and increased KIBRA in cerebrospinal fluid are associated with cognitive impairment and pathological tau levels in disease. Thus, our results distinguish KIBRA both as a novel biomarker of synapse dysfunction in AD and as the foundation for a synapse repair mechanism to reverse cognitive impairment in tauopathy.
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Affiliation(s)
- Grant Kauwe
- Buck Institute for Research on Aging, Novato, CA USA
| | | | - Lei Yao
- Buck Institute for Research on Aging, Novato, CA USA
| | | | - Ivy Wong
- Buck Institute for Research on Aging, Novato, CA USA
| | - Rowan Saloner
- Memory and Aging Center, Department of Neurology, University of California, San Francisco USA
| | | | - Alissa L. Nana
- Memory and Aging Center, Department of Neurology, University of California, San Francisco USA
| | - Samah Shah
- Buck Institute for Research on Aging, Novato, CA USA
| | - Yaqiao Li
- Gladstone Institutes, San Francisco, CA USA
| | - David Le
- Gladstone Institutes, San Francisco, CA USA
| | - Salvatore Spina
- Memory and Aging Center, Department of Neurology, University of California, San Francisco USA
| | - Lea T. Grinberg
- Memory and Aging Center, Department of Neurology, University of California, San Francisco USA
- Weill Institute for Neurosciences, Department of Pathology, University of California, San Francisco USA
| | - William W. Seeley
- Memory and Aging Center, Department of Neurology, University of California, San Francisco USA
- Weill Institute for Neurosciences, Department of Pathology, University of California, San Francisco USA
| | - Joel H. Kramer
- Memory and Aging Center, Department of Neurology, University of California, San Francisco USA
| | - Todd C. Sacktor
- The Robert F. Furchgott Center of Neural and Behavioral Science, Departments of Physiology and Pharmacology, Anesthesiology, and Neurology, State University of New York Health Sciences University, Brooklyn, NY USA
| | | | - Li Gan
- Helen and Robert Appel Alzheimer Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY USA
| | - Kaitlin B. Casaletto
- Memory and Aging Center, Department of Neurology, University of California, San Francisco USA
| | - Tara E. Tracy
- Buck Institute for Research on Aging, Novato, CA USA
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6
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Sacktor TC. Karim Nader and the unification of memory erasure: PKMζ inhibition and reconsolidation blockade. Brain Res Bull 2023; 194:124-127. [PMID: 36739095 DOI: 10.1016/j.brainresbull.2023.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 01/31/2023] [Accepted: 02/01/2023] [Indexed: 02/05/2023]
Abstract
Karim Nader is rightly celebrated for his seminal studies on memory reconsolidation. This commentary celebrates another related contribution - his work on memory maintenance by the autonomously active PKC isoform, PKMζ. There are two methods for "erasing" previously established long-term memory maintenance: 1) inhibiting PKMζ, and 2) blocking reconsolidation. Prior to Nader's research on PKMζ, these two forms of memory erasure were thought to be fundamentally different. Inhibiting PKMζ in a brain region disrupts memory held in storage. But if the inhibitor is injected into the same region immediately after memory retrieval, the drug has no effect. Conversely, inhibiting protein synthesis immediately after memory retrieval blocks reconsolidation. But protein synthesis inhibitors have no effect on memory held in storage without retrieval. The work of Paolo Virginia Migues, Nader, and colleagues, however, revealed an unexpected link between the mechanisms of memory maintenance by PKMζ and the kinase's regulation of postsynaptic AMPAR trafficking that potentiates synaptic transmission and expresses memory during retrieval. This insight led Matteo Bernabo, Nader, and colleagues to observe that memory retrieval first rapidly degrades PKMζ, and then induces the resynthesis of the kinase to restore maintenance of the retrieved memory. This finding explains why a PKMζ inhibitor such as ZIP, if injected in a brain region storing a memory, does not erase the memory immediately after retrieval - the kinase maintaining the retrieved memory has been degraded but not yet resynthesized. Moreover, Bernabo et al. showed that suppressing the resynthesis of PKMζ after its degradation prevents memory reconsolidation, reproducing the effect of general protein synthesis inhibition. Thus, Nader and colleagues demonstrated PKMζ inhibition and reconsolidation blockade disrupt in different ways the same molecular mechanism of memory maintenance - PKMζ inhibition erases all memories maintained in storage by the kinase; reconsolidation blockade disrupts specific recalled memories maintained by PKMζ by preventing resynthesis of the kinase after its degradation.
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Affiliation(s)
- Todd Charlton Sacktor
- Departments of Physiology and Pharmacology, Anesthesiology, and Neurology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Health Sciences University, Brooklyn, NY 11203, USA.
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7
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Pramio DT, Vieceli FM, Varella-Branco E, Goes CP, Kobayashi GS, da Silva Pelegrina DV, de Moraes BC, El Allam A, De Kumar B, Jara G, Farfel JM, Bennett DA, Kundu S, Viapiano MS, Reis EM, de Oliveira PSL, Dos Santos E Passos-Bueno MR, Rothlin CV, Ghosh S, Schechtman D. DNA methylation of the promoter region at the CREB1 binding site is a mechanism for the epigenetic regulation of brain-specific PKMζ. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2023; 1866:194909. [PMID: 36682583 PMCID: PMC10037092 DOI: 10.1016/j.bbagrm.2023.194909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 01/05/2023] [Accepted: 01/13/2023] [Indexed: 01/21/2023]
Abstract
Protein kinase M zeta, PKMζ, is a brain enriched kinase with a well characterized role in Long-Term Potentiation (LTP), the activity-dependent strengthening of synapses involved in long-term memory formation. However, little is known about the molecular mechanisms that maintain the tissue specificity of this kinase. Here, we characterized the epigenetic factors, mainly DNA methylation, regulating PKMζ expression in the human brain. The PRKCZ gene has an upstream promoter regulating Protein kinase C ζ (PKCζ), and an internal promoter driving PKMζ expression. A demethylated region, including a canonical CREB binding site, situated at the internal promoter was only observed in human CNS tissues. The induction of site-specific hypermethylation of this region resulted in decreased CREB1 binding and downregulation of PKMζ expression. Noteworthy, CREB binding sites were absent in the upstream promoter of PRKCZ locus, suggesting a specific mechanism for regulating PKMζ expression. These observations were validated using a system of human neuronal differentiation from induced pluripotent stem cells (iPSCs). CREB1 binding at the internal promoter was detected only in differentiated neurons, where PKMζ is expressed. The same epigenetic mechanism in the context of CREB binding site was identified in other genes involved in neuronal differentiation and LTP. Additionally, aberrant DNA hypermethylation at the internal promoter was observed in cases of Alzheimer's disease, correlating with decreased expression of PKMζ in patient brains. Altogether, we present a conserved epigenetic mechanism regulating PKMζ expression and other genes enhanced in the CNS with possible implications in neuronal differentiation and Alzheimer's disease.
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Affiliation(s)
| | | | | | - Carolina Purcell Goes
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, SP, Brazil; Laboratory of Neuromodulation of Experimental Pain, Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, SP, Brazil
| | | | | | | | - Aicha El Allam
- Department of Neurology, Yale School of Medicine, New Haven, CT, USA
| | | | - Gabriel Jara
- Brazilian Center for Research in Energy and Materials (CNPEM), Brazilian National Biosciences Laboratory (LNBio) Campinas, SP, Brazil
| | - José Marcelo Farfel
- Traumatology and Orthopedy Department, Faculdade de Medicina, Universidade de São Paulo, SP, Brazil; Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA; Health Sciences Program, Instituto de Assistência Medica ao Servidor Público do Estado (IAMSPE), SP, Brazil
| | - David Alan Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA
| | - Somanath Kundu
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Mariano S Viapiano
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Eduardo Moraes Reis
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, SP, Brazil
| | - Paulo Sergio Lopes de Oliveira
- Brazilian Center for Research in Energy and Materials (CNPEM), Brazilian National Biosciences Laboratory (LNBio) Campinas, SP, Brazil
| | | | - Carla V Rothlin
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA; Department of Pharmacology, Yale School of Medicine, New Haven, CT, USA
| | - Sourav Ghosh
- Department of Neurology, Yale School of Medicine, New Haven, CT, USA; Department of Pharmacology, Yale School of Medicine, New Haven, CT, USA.
| | - Deborah Schechtman
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, SP, Brazil.
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Augereau K, Migues PV, Hardt O. Infusing zeta inhibitory peptide into the perirhinal cortex of rats abolishes long-term object recognition memory without affecting novel object location recognition. Front Behav Neurosci 2022; 16:1007748. [PMID: 36560931 PMCID: PMC9763881 DOI: 10.3389/fnbeh.2022.1007748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 11/07/2022] [Indexed: 12/12/2022] Open
Abstract
Infusing the amnesic agent zeta inhibitory peptide (ZIP) into the dorsal hippocampus disrupts established long-term object location recognition memory without affecting object identity recognition, which likely depends on the perirhinal cortex. Here, we tested whether infusing ZIP into the perirhinal cortex can abolish long-term memory supporting object identity recognition, leaving long-term object location recognition memory intact. We infused ZIP into the perirhinal cortex of rats either 1 day or 6 days after exposing them to two identical objects in an open field arena. One day after ZIP infusion, that is, 2 or 7 days after object exposure, we either assessed whether the animals recognized that now one of the two objects was novel or whether they recognized that one of the two familiar objects was at a new location. Our results show for both retention intervals, infusions of ZIP into the perirhinal cortex impaired novel object recognition but spared novel object location recognition. Rats that received a scrambled version of ZIP had no deficit in either test at both retention intervals and expressed stronger novel object recognition compared to rats infused with ZIP. These findings support the view that object recognition depends on dissociable memory representations distributed across different brain areas, with perirhinal cortex maintaining long-term memory for what objects had been encountered, and hippocampus supporting memory for where these objects had been placed.
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9
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Min C, Ling R, Chen M, Xia D, Chen R, Li X. Enriched environment rescues neonatal pain induced cognitive deficits and the impaired hippocampal synaptic plasticity later in life. Dev Neurobiol 2022; 82:545-561. [PMID: 35945168 DOI: 10.1002/dneu.22898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 05/04/2022] [Accepted: 07/27/2022] [Indexed: 11/06/2022]
Abstract
Although extensive and untreated pain that occurs during a critical developmental window may impair cognition later in life, environmental interventions at early might promote. However, the underlying mechanism is poorly understood. Our current study utilized a rat model of "repetitive needle pricks" from the day of birth (P0) to postnatal day 7 (P7) to mimic the painful experience of preterm neonates in the Neonatal intensive care unit (NICU). Enriched environment (EE) during development period (from P15 to P70) was implemented as a nonpharmacological intervention approach. Electrophysiological recording, behavioral tests and biochemical analysis were performed after the end of EE (between P71 and P80). Results showed neonatal repetitive pain resulted in a reduction in mechanical withdrawal thresholds by the von Frey test in P70 (P < 0.001). Furthermore, neonatal repetitive pain impaired spatial learning and memory (P < 0.05) and even led to dysfunction in fear memory (P < 0.01). In contrast, EE rescued neonatal pain induced cognitive deficits and normalized hippocampal long-term potentiation in rats exposed to neonatal pain (P < 0.05). The beneficial effect of EE might be the improvements in hippocampal synaptic plasticity via up-regulating neurotrophic factors and N-methyl-D-aspartate (NMDA) receptors in the hippocampus. Our findings provide evidence that early environmental intervention might be a safe strategy to overcome neurodevelopmental abnormalities in preterm infants who experienced multiple procedural painful events during the early critical period. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Cuiting Min
- Department of Child Health Care, Children's Hospital of Nanjing Medical University, No.72 Guangzhou Road, Nanjing, Jiangsu Province, 210008, P.R. China
| | - Ru Ling
- Department of Child Health Care, Children's Hospital of Nanjing Medical University, No.72 Guangzhou Road, Nanjing, Jiangsu Province, 210008, P.R. China
| | - Mengying Chen
- Department of Child Health Care, Children's Hospital of Nanjing Medical University, No.72 Guangzhou Road, Nanjing, Jiangsu Province, 210008, P.R. China
| | - Dongqing Xia
- Department of Child Health Care, Children's Hospital of Nanjing Medical University, No.72 Guangzhou Road, Nanjing, Jiangsu Province, 210008, P.R. China
| | - Ran Chen
- Department of Child Health Care, Children's Hospital of Nanjing Medical University, No.72 Guangzhou Road, Nanjing, Jiangsu Province, 210008, P.R. China
| | - Xiaonan Li
- Department of Child Health Care, Children's Hospital of Nanjing Medical University, No.72 Guangzhou Road, Nanjing, Jiangsu Province, 210008, P.R. China
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10
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Nicotine alleviates alcohol-induced memory and long-term potentiation impairment. Neurosci Lett 2022; 786:136813. [PMID: 35878655 DOI: 10.1016/j.neulet.2022.136813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 11/21/2022]
Abstract
Alcohol and nicotine are routinely abused together. There is one plausible explanation that comorbidity can alleviate alcohol-induced cognitive impairment. However, the mechanism involved is not known. The aim of this report was to evaluate the interactive effects of alcohol coadministration with nicotine on hippocampal memory and long-term potentiation (LTP). C57BL/6 mice were distributed into 4 treatment groups: control, alcohol, nicotine, and alcohol plus nicotine. All mice received tap water or alcohol solution and saline or nicotine. In water maze test, the alcohol group showed significant decreases in hippocampus function and acquisition training than control, nicotine, and combined treatment groups. The alcohol group also showed a significantly shorter latency in entering the foot-shock compartment than control, nicotine, and combined treatment groups in a passive avoidance test. Theta burst stimulation was adopted to induce concrete LTP in CA1 field recording using hippocampal slice. Alcohol alone administration failed to maintain LTP. Nicotine alone administration did not alter hippocampal LTP. There were no negative effects of alcohol on hippocampal LTP in mice administrated with nicotine. The current study successfully demonstrated beneficial effects of nicotine on alcohol induced memory impairment accompanied by hippocampal LTP impairment after one week of co-administration and one-day withdrawal.
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11
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The Roles of Par3, Par6, and aPKC Polarity Proteins in Normal Neurodevelopment and in Neurodegenerative and Neuropsychiatric Disorders. J Neurosci 2022; 42:4774-4793. [PMID: 35705493 DOI: 10.1523/jneurosci.0059-22.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/30/2022] [Accepted: 05/02/2022] [Indexed: 11/21/2022] Open
Abstract
Normal neural circuits and functions depend on proper neuronal differentiation, migration, synaptic plasticity, and maintenance. Abnormalities in these processes underlie various neurodevelopmental, neuropsychiatric, and neurodegenerative disorders. Neural development and maintenance are regulated by many proteins. Among them are Par3, Par6 (partitioning defective 3 and 6), and aPKC (atypical protein kinase C) families of evolutionarily conserved polarity proteins. These proteins perform versatile functions by forming tripartite or other combinations of protein complexes, which hereafter are collectively referred to as "Par complexes." In this review, we summarize the major findings on their biophysical and biochemical properties in cell polarization and signaling pathways. We next summarize their expression and localization in the nervous system as well as their versatile functions in various aspects of neurodevelopment, including neuroepithelial polarity, neurogenesis, neuronal migration, neurite differentiation, synaptic plasticity, and memory. These versatile functions rely on the fundamental roles of Par complexes in cell polarity in distinct cellular contexts. We also discuss how cell polarization may correlate with subcellular polarization in neurons. Finally, we review the involvement of Par complexes in neuropsychiatric and neurodegenerative disorders, such as schizophrenia and Alzheimer's disease. While emerging evidence indicates that Par complexes are essential for proper neural development and maintenance, many questions on their in vivo functions have yet to be answered. Thus, Par3, Par6, and aPKC continue to be important research topics to advance neuroscience.
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12
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Huertas MA, Newton AJH, McDougal RA, Sacktor TC, Shouval HZ. Conditions for Synaptic Specificity during the Maintenance Phase of Synaptic Plasticity. eNeuro 2022; 9:ENEURO.0064-22.2022. [PMID: 35443991 PMCID: PMC9087736 DOI: 10.1523/eneuro.0064-22.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 03/31/2022] [Indexed: 01/21/2023] Open
Abstract
Activity-dependent modifications of synaptic efficacies are a cellular substrate of learning and memory. Experimental evidence shows that these modifications are synapse specific and that the long-lasting effects are associated with the sustained increase in concentration of specific proteins like PKMζ However, such proteins are likely to diffuse away from their initial synaptic location and spread out to neighboring synapses, potentially compromising synapse specificity. In this article, we address the issue of synapse specificity during memory maintenance. Assuming that the long-term maintenance of synaptic plasticity is accomplished by a molecular switch, we carry out analytical calculations and perform simulations using the reaction-diffusion package in NEURON to determine the limits of synapse specificity during maintenance. Moreover, we explore the effects of the diffusion and degradation rates of proteins and of the geometrical characteristics of dendritic spines on synapse specificity. We conclude that the necessary conditions for synaptic specificity during maintenance require that molecular switches reside in dendritic spines. The requirement for synaptic specificity when the molecular switch resides in spines still imposes strong limits on the diffusion and turnover of rates of maintenance molecules, as well as on the morphologic properties of synaptic spines. These constraints are quite general and apply to most existing models suggested for maintenance. The parameter values can be experimentally evaluated, and if they do not fit the appropriate predicted range, the validity of this class of maintenance models would be challenged.
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Affiliation(s)
- Marco A Huertas
- Department of Neurobiology and Anatomy, University of Texas Medical School, Houston, TX 77030
| | - Adam J H Newton
- Yale Center for Medical Informatics, New Haven, CT 06520
- Department of Biostatistics, Yale School of Public Health, New Haven, CT 06520
- Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, NY 11203
| | - Robert A McDougal
- Yale Center for Medical Informatics, New Haven, CT 06520
- Department of Biostatistics, Yale School of Public Health, New Haven, CT 06520
| | - Todd Charlton Sacktor
- Department of Physiology, Pharmacology, Anesthesiology, and Neurology, SUNY Downstate Health Sciences University, Brooklyn, NY 11203
| | - Harel Z Shouval
- Department of Neurobiology and Anatomy, University of Texas Medical School, Houston, TX 77030
- Department Electrical and Computer Engineering, Rice University, Houston, TX 77005
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13
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Marcondes LA, de C Myskiw J, Nachtigall EG, Narvaes RF, Izquierdo I, Furini CRG. PKMζ maintains remote contextual fear memory by inhibiting GluA2-dependent AMPA receptor endocytosis in the prelimbic cortex. Neuroscience 2021; 497:97-106. [PMID: 34968669 DOI: 10.1016/j.neuroscience.2021.12.028] [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: 10/07/2021] [Revised: 12/10/2021] [Accepted: 12/21/2021] [Indexed: 10/19/2022]
Abstract
Fear memories allow animals to recognize and adequately respond to dangerous situations. The prelimbic cortex (PrL) is a crucial node in the circuitry that encodes contextual fear memory, and its activity is central for fear memory expression over time. However, while PrL has been implicated in contextual fear memory storage, the molecular mechanisms underlying its maintenance remain unclear. Protein kinase M zeta (PKMζ) is a persistently active enzyme which has been shown to maintain many forms of memories by inhibiting the endocytosis of GluA2-containing AMPA receptors. Therefore, we hypothesized that PKMζ action upon GluA2-containing AMPARs could be a mechanism for contextual fear memory maintenance in the PrL. To test this hypothesis, we trained rats in a contextual fear conditioning (CFC) paradigm and administered intra-PrL infusions of the PKMζ inhibitor ZIP, the GluA2-dependent endocytosis inhibitor GluA23Y or the inactive peptide GluA23Y(s), either two or twenty days after conditioning, and assessed long-term memory retention twenty-four hours later. We found that acute inhibition of GluA2-dependent AMPAR endocytosis in the PrL does not affect recent or remote contextual fear memory maintenance. Also, PKMζ inhibition in the PrL does not impair the maintenance of recent contextual fear memory. However, we found that inhibition of prelimbic PKMζ at a remote time point disrupted contextual fear memory maintenance, and that blocking GluA2-dependent removal of AMPARs prevents this impairment. Our results confirm the central role of PrL in fear memory and identify PKMζ-induced inhibition of GluA2-containing AMPAR endocytosis as a key mechanism governing remote contextual fear memory maintenance.
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Affiliation(s)
- Lucas A Marcondes
- Laboratory of Cognition and Memory Neurobiology, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 3(rd) floor, 90610-000, Porto Alegre, RS, Brazil; Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2(nd) floor - HSL, 90610-000, Porto Alegre, RS, Brazil
| | - Jociane de C Myskiw
- Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2(nd) floor - HSL, 90610-000, Porto Alegre, RS, Brazil
| | - Eduarda G Nachtigall
- Laboratory of Cognition and Memory Neurobiology, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 3(rd) floor, 90610-000, Porto Alegre, RS, Brazil; Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2(nd) floor - HSL, 90610-000, Porto Alegre, RS, Brazil
| | - Rodrigo F Narvaes
- Laboratory of Cognition and Memory Neurobiology, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 3(rd) floor, 90610-000, Porto Alegre, RS, Brazil; Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2(nd) floor - HSL, 90610-000, Porto Alegre, RS, Brazil
| | - Ivan Izquierdo
- Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2(nd) floor - HSL, 90610-000, Porto Alegre, RS, Brazil
| | - Cristiane R G Furini
- Laboratory of Cognition and Memory Neurobiology, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 3(rd) floor, 90610-000, Porto Alegre, RS, Brazil; Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2(nd) floor - HSL, 90610-000, Porto Alegre, RS, Brazil.
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14
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Cui D, Jiang X, Chen M, Sheng H, Shao D, Yang L, Guo X, Wang Y, Lai B, Zheng P. Activation of Rac1 Has an Opposing Effect on Induction and Maintenance of Long-Term Potentiation in Hippocampus by Acting on Different Kinases. Front Mol Neurosci 2021; 14:720371. [PMID: 34531724 PMCID: PMC8438208 DOI: 10.3389/fnmol.2021.720371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 07/27/2021] [Indexed: 11/21/2022] Open
Abstract
Rac1 is a small GTPase of the Rho family. A previous study showed that the activation of Rac1 had an opposing effect on induction and maintenance of long-term potentiation (LTP) in the hippocampus. However, the molecular mechanism underlying this opposing effect remains to be addressed. In the present work, we find that the activation of Rac1 during the induction of LTP leads to an activation of PKCι/λ by phosphatidylinositol-3-kinase (PI3K), whereas the activation of Rac1 during the maintenance of LTP leads to the inhibition of PKMζ by LIM_kinase (LIMK) in the hippocampus. This result suggests that during different stages of LTP, the activation of Rac1 can modulate different signaling pathways, which leads to an opposing effect on the induction and maintenance of LTP in the hippocampus.
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Affiliation(s)
- Dongyang Cui
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Xiaodong Jiang
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Ming Chen
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Huan Sheng
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Da Shao
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Li Yang
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Xinli Guo
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Yingqi Wang
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Bin Lai
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Ping Zheng
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, MOE Frontier Center for Brain Science, School of Basic Medical Sciences, Fudan University, Shanghai, China.,Department of Neurology of Zhongshan Hospital, Fudan University, Shanghai, China.,Department of Pharmacology of Medical College of China Three Gorges University, Yichang, China
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15
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Zhang HL, Zhao B, Yang P, Du YQ, Han W, Xu J, Yin DM. Steroid Receptor Coactivator 3 Regulates Synaptic Plasticity and Hippocampus-dependent Memory. Neurosci Bull 2021; 37:1645-1657. [PMID: 34228315 PMCID: PMC8643392 DOI: 10.1007/s12264-021-00741-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 02/27/2021] [Indexed: 11/28/2022] Open
Abstract
Steroid hormones play important roles in brain development and function. The signaling of steroid hormones depends on the interaction between steroid receptors and their coactivators. Although the function of steroid receptor coactivators has been extensively studied in other tissues, their functions in the central nervous system are less well investigated. In this study, we addressed the function of steroid receptor coactivator 3 (SRC3) - a member of the p160 SRC protein family that is expressed predominantly in the hippocampus. While hippocampal development was not altered in Src3+/- mice, hippocampus-dependent functions such as short-term memory and spatial memory were impaired. We further demonstrated that the deficient learning and memory in Src3+/- mice was strongly associated with the impairment of long-term potentiation (LTP) at Schaffer Collateral-CA1 synapses. Mechanistic studies indicated that Src3+/- mutation altered the composition of N-methyl-D-aspartate receptor subunits in the postsynaptic densities of hippocampal neurons. Finally, we showed that SRC3 regulated synaptic plasticity and learning mainly dependent on its lysine acetyltransferase activity. Taken together, these results reveal previously unknown functions of SRC3 in the hippocampus and thus may provide insight into how steroid hormones regulate brain function.
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Affiliation(s)
- Hai-Long Zhang
- Key Laboratory of Brain Functional Genomics, Ministry of Education and Shanghai, School of Life Science, East China Normal University, Shanghai, 200062, China
| | - Bing Zhao
- MOE Frontiers Center for Brain Science, Institute for Translational Brain Research, Fudan University, Shanghai, 200032, China
| | - Pin Yang
- Key Laboratory of Brain Functional Genomics, Ministry of Education and Shanghai, School of Life Science, East China Normal University, Shanghai, 200062, China
| | - Yin-Quan Du
- Key Laboratory of Brain Functional Genomics, Ministry of Education and Shanghai, School of Life Science, East China Normal University, Shanghai, 200062, China
| | - Wei Han
- Key Laboratory of Brain Functional Genomics, Ministry of Education and Shanghai, School of Life Science, East China Normal University, Shanghai, 200062, China
| | - Jianming Xu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Dong-Min Yin
- Key Laboratory of Brain Functional Genomics, Ministry of Education and Shanghai, School of Life Science, East China Normal University, Shanghai, 200062, China.
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16
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Patel H, Zamani R. The role of PKMζ in the maintenance of long-term memory: a review. Rev Neurosci 2021; 32:481-494. [PMID: 33550786 DOI: 10.1515/revneuro-2020-0105] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 11/27/2020] [Indexed: 11/15/2022]
Abstract
Long-term memories are thought to be stored in neurones and synapses that undergo physical changes, such as long-term potentiation (LTP), and these changes can be maintained for long periods of time. A candidate enzyme for the maintenance of LTP is protein kinase M zeta (PKMζ), a constitutively active protein kinase C isoform that is elevated during LTP and long-term memory maintenance. This paper reviews the evidence and controversies surrounding the role of PKMζ in the maintenance of long-term memory. PKMζ maintains synaptic potentiation by preventing AMPA receptor endocytosis and promoting stabilisation of dendritic spine growth. Inhibition of PKMζ, with zeta-inhibitory peptide (ZIP), can reverse LTP and impair established long-term memories. However, a deficit of memory retrieval cannot be ruled out. Furthermore, ZIP, and in high enough doses the control peptide scrambled ZIP, was recently shown to be neurotoxic, which may explain some of the effects of ZIP on memory impairment. PKMζ knockout mice show normal learning and memory. However, this is likely due to compensation by protein-kinase C iota/lambda (PKCι/λ), which is normally responsible for induction of LTP. It is not clear how, or if, this compensatory mechanism is activated under normal conditions. Future research should utilise inducible PKMζ knockdown in adult rodents to investigate whether PKMζ maintains memory in specific parts of the brain, or if it represents a global memory maintenance molecule. These insights may inform future therapeutic targets for disorders of memory loss.
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Affiliation(s)
- Hamish Patel
- University of Exeter Medical School, Exeter, EX1 2LU, UK
| | - Reza Zamani
- University of Exeter Medical School, Exeter, EX1 2LU, UK
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17
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Hsieh C, Tsokas P, Grau-Perales A, Lesburguères E, Bukai J, Khanna K, Chorny J, Chung A, Jou C, Burghardt NS, Denny CA, Flores-Obando RE, Hartley BR, Rodríguez Valencia LM, Hernández AI, Bergold PJ, Cottrell JE, Alarcon JM, Fenton AA, Sacktor TC. Persistent increases of PKMζ in memory-activated neurons trace LTP maintenance during spatial long-term memory storage. Eur J Neurosci 2021; 54:6795-6814. [PMID: 33540466 DOI: 10.1111/ejn.15137] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 01/28/2021] [Indexed: 01/12/2023]
Abstract
PKMζ is an autonomously active PKC isoform crucial for the maintenance of synaptic long-term potentiation (LTP) and long-term memory. Unlike other kinases that are transiently stimulated by second messengers, PKMζ is persistently activated through sustained increases in protein expression of the kinase. Therefore, visualizing increases in PKMζ expression during long-term memory storage might reveal the sites of its persistent action and thus the location of memory-associated LTP maintenance in the brain. Using quantitative immunohistochemistry validated by the lack of staining in PKMζ-null mice, we examined the amount and distribution of PKMζ in subregions of the hippocampal formation of wild-type mice during LTP maintenance and spatial long-term memory storage. During LTP maintenance in hippocampal slices, PKMζ increases in the pyramidal cell body and stimulated dendritic layers of CA1 for at least 2 hr. During spatial memory storage, PKMζ increases in CA1 pyramidal cells for at least 1 month, paralleling the persistence of the memory. During the initial expression of the memory, we tagged principal cells with immediate-early gene Arc promoter-driven transcription of fluorescent proteins. The subset of memory-tagged CA1 cells selectively increases expression of PKMζ during memory storage, and the increase persists in dendritic compartments within stratum radiatum for 1 month, indicating long-term storage of information in the CA3-to-CA1 pathway. We conclude that persistent increases in PKMζ trace the molecular mechanism of LTP maintenance and thus the sites of information storage within brain circuitry during long-term memory.
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Affiliation(s)
- Changchi Hsieh
- Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, New York, USA
| | - Panayiotis Tsokas
- Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, New York, USA.,Department of Anesthesiology, State University of New York Downstate Health Sciences University, Brooklyn, New York, USA
| | | | | | - Joseph Bukai
- Department of Pathology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, New York, USA
| | - Kunal Khanna
- Department of Pathology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, New York, USA
| | - Joelle Chorny
- Department of Pathology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, New York, USA
| | - Ain Chung
- Center for Neural Science, New York University, New York, New York, USA
| | - Claudia Jou
- Department of Psychology, Hunter College, The City University of New York, New York, NY, USA.,Department of Psychology, The Graduate Center, The City University of New York, New York, NY, USA
| | - Nesha S Burghardt
- Department of Psychology, Hunter College, The City University of New York, New York, NY, USA.,Department of Psychology, The Graduate Center, The City University of New York, New York, NY, USA
| | - Christine A Denny
- Department of Psychiatry, Columbia University Irving Medical Center, Division of Systems Neuroscience, Research Foundation for Mental Hygiene, Inc, New York State Psychiatric Institute Kolb Research Annex, New York, NY, USA
| | - Rafael E Flores-Obando
- Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, New York, USA
| | - Benjamin Rush Hartley
- Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, New York, USA
| | | | - A Iván Hernández
- Department of Pathology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, New York, USA
| | - Peter J Bergold
- Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, New York, USA.,Department of Neurology, State University of New York Downstate Health Sciences University, Brooklyn, NY, USA
| | - James E Cottrell
- Department of Anesthesiology, State University of New York Downstate Health Sciences University, Brooklyn, New York, USA
| | - Juan Marcos Alarcon
- Department of Pathology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, New York, USA
| | - André Antonio Fenton
- Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, New York, USA.,Center for Neural Science, New York University, New York, New York, USA
| | - Todd Charlton Sacktor
- Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Health Sciences University, Brooklyn, New York, USA.,Department of Anesthesiology, State University of New York Downstate Health Sciences University, Brooklyn, New York, USA.,Department of Neurology, State University of New York Downstate Health Sciences University, Brooklyn, NY, USA
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18
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Smolen P, Baxter DA, Byrne JH. Comparing Theories for the Maintenance of Late LTP and Long-Term Memory: Computational Analysis of the Roles of Kinase Feedback Pathways and Synaptic Reactivation. Front Comput Neurosci 2020; 14:569349. [PMID: 33390922 PMCID: PMC7772319 DOI: 10.3389/fncom.2020.569349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 11/16/2020] [Indexed: 11/26/2022] Open
Abstract
A fundamental neuroscience question is how memories are maintained from days to a lifetime, given turnover of proteins that underlie expression of long-term synaptic potentiation (LTP) or “tag” synapses as eligible for LTP. A likely solution relies on synaptic positive feedback loops, prominently including persistent activation of Ca2+/calmodulin kinase II (CaMKII) and self-activated synthesis of protein kinase M ζ (PKMζ). Data also suggest positive feedback based on recurrent synaptic reactivation within neuron assemblies, or engrams, is necessary to maintain memories. The relative importance of these mechanisms is controversial. To explore the likelihood that each mechanism is necessary or sufficient to maintain memory, we simulated maintenance of LTP with a simplified model incorporating persistent kinase activation, synaptic tagging, and preferential reactivation of strong synapses, and analyzed implications of recent data. We simulated three model variants, each maintaining LTP with one feedback loop: autonomous, self-activated PKMζ synthesis (model variant I); self-activated CamKII (model variant II); and recurrent reactivation of strengthened synapses (model variant III). Variant I predicts that, for successful maintenance of LTP, either 1) PKMζ contributes to synaptic tagging, or 2) a low constitutive tag level persists during maintenance independent of PKMζ, or 3) maintenance of LTP is independent of tagging. Variant II maintains LTP and suggests persistent CaMKII activation could maintain PKMζ activity, a feedforward interaction not previously considered. However, we note data challenging the CaMKII feedback loop. In Variant III synaptic reactivation drives, and thus predicts, recurrent or persistent activation of CamKII and other necessary kinases, plausibly contributing to persistent elevation of PKMζ levels. Reactivation is thus predicted to sustain recurrent rounds of synaptic tagging and incorporation of plasticity-related proteins. We also suggest (model variant IV) that synaptic reactivation and autonomous kinase activation could synergistically maintain LTP. We propose experiments that could discriminate these maintenance mechanisms.
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Affiliation(s)
- Paul Smolen
- Department of Neurobiology and Anatomy, W.M. Keck Center for the Neurobiology of Learning and Memory, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Douglas A Baxter
- Department of Neurobiology and Anatomy, W.M. Keck Center for the Neurobiology of Learning and Memory, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, United States.,Engineering and Medicine, Texas A&M Health Science Center, Houston, TX, United States
| | - John H Byrne
- Department of Neurobiology and Anatomy, W.M. Keck Center for the Neurobiology of Learning and Memory, McGovern Medical School at the University of Texas Health Science Center at Houston, Houston, TX, United States
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19
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Smolen P, Wood MA, Baxter DA, Byrne JH. Modeling suggests combined-drug treatments for disorders impairing synaptic plasticity via shared signaling pathways. J Comput Neurosci 2020; 49:37-56. [PMID: 33175283 DOI: 10.1007/s10827-020-00771-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 08/27/2020] [Accepted: 10/19/2020] [Indexed: 12/15/2022]
Abstract
Genetic disorders such as Rubinstein-Taybi syndrome (RTS) and Coffin-Lowry syndrome (CLS) cause lifelong cognitive disability, including deficits in learning and memory. Can pharmacological therapies be suggested that improve learning and memory in these disorders? To address this question, we simulated drug effects within a computational model describing induction of late long-term potentiation (L-LTP). Biochemical pathways impaired in these and other disorders converge on a common target, histone acetylation by acetyltransferases such as CREB binding protein (CBP), which facilitates gene induction necessary for L-LTP. We focused on four drug classes: tropomyosin receptor kinase B (TrkB) agonists, cAMP phosphodiesterase inhibitors, histone deacetylase inhibitors, and ampakines. Simulations suggested each drug type alone may rescue deficits in L-LTP. A potential disadvantage, however, was the necessity of simulating strong drug effects (high doses), which could produce adverse side effects. Thus, we investigated the effects of six drug pairs among the four classes described above. These combination treatments normalized impaired L-LTP with substantially smaller individual drug 'doses'. In addition three of these combinations, a TrkB agonist paired with an ampakine and a cAMP phosphodiesterase inhibitor paired with a TrkB agonist or an ampakine, exhibited strong synergism in L-LTP rescue. Therefore, we suggest these drug combinations are promising candidates for further empirical studies in animal models of genetic disorders that impair histone acetylation, L-LTP, and learning.
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Affiliation(s)
- Paul Smolen
- 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.
| | - Marcelo A Wood
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA, 92697, USA
| | - Douglas A Baxter
- 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
- 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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Song S, Kim J, Park K, Lee J, Park S, Lee S, Kim J, Hong I, Song B, Choi S. GSK-3β activation is required for ZIP-induced disruption of learned fear. Sci Rep 2020; 10:18227. [PMID: 33106552 PMCID: PMC7588416 DOI: 10.1038/s41598-020-75130-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 10/05/2020] [Indexed: 11/12/2022] Open
Abstract
The myristoylated zeta inhibitory peptide (ZIP), which was originally developed as a protein kinase C/Mζ (PKCζ/PKMζ) inhibitor, is known to produce the loss of different forms of memories. However, ZIP induces memory loss even in the absence of PKMζ, and its mechanism of action, therefore, remains elusive. Here, through a kinome-wide screen, we found that glycogen synthase kinase 3 beta (GSK-3β) was robustly activated by ZIP in vitro. ZIP induced depotentiation (a cellular substrate of memory erasure) of conditioning-induced potentiation at LA synapses, and the ZIP-induced depotentiation was prevented by a GSK-3β inhibitor, 6-bromoindirubin-3-acetoxime (BIO-acetoxime). Consistently, GSK-3β inhibition by BIO-acetoxime infusion or GSK-3β knockdown by GSK-3β shRNA in the LA attenuated ZIP-induced disruption of learned fear. Furthermore, conditioned fear was decreased by expression of a non-inhibitable form of GSK-3β in the LA. Our findings suggest that GSK-3β activation is a critical step for ZIP-induced disruption of memory.
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Affiliation(s)
- Sukwoon Song
- School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Jihye Kim
- School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Kyungjoon Park
- Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA, 02478, USA
| | - Junghwa Lee
- School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Sewon Park
- School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Sukwon Lee
- Department of Neural Development and Disease, Korea Brain Research Institute, Daegu, Republic of Korea
| | - Jeongyeon Kim
- Department of Neural Development and Disease, Korea Brain Research Institute, Daegu, Republic of Korea
| | - Ingie Hong
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Beomjong Song
- International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, Tokyo, Japan.
| | - Sukwoo Choi
- School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea.
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George NC, Laferrière A, Coderre TJ. Sex differences in the contributions of spinal atypical PKCs and downstream targets to the maintenance of nociceptive sensitization. Mol Pain 2020; 15:1744806919840582. [PMID: 30857476 PMCID: PMC6537080 DOI: 10.1177/1744806919840582] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background Chronic pain has been shown to depend on nociceptive sensitization in the spinal cord, and while multiple mechanisms involved in the initiation of plastic changes have been established, the molecular targets which maintain spinal nociceptive sensitization are still largely unknown. Building upon the established neurobiology underlying the maintenance of long-term potentiation in the hippocampus, this present study investigated the contributions of spinal atypical protein kinase C (PKC) isoforms PKCι/λ and PKMζ and their downstream targets (p62/GluA1 and NSF/GluA2 interactions, respectively) to the maintenance of spinal nociceptive sensitization in male and female rats. Results Pharmacological inhibition of atypical PKCs by ZIP reversed established allodynia produced by repeated intramuscular acidic saline injections in male animals only, replicating previously demonstrated sex differences. Inhibition of both PKCι/λ and downstream substrates p62/GluA1 resulted in male-specific reversals of intramuscular acidic saline-induced allodynia, while female animals continued to display allodynia. Inhibition of NSF/GluA2, the downstream target to PKMζ, reversed allodynia induced by intramuscular acidic saline in both sexes. Neither PKCι/λ, p62/GluA1 or NSF/GluA2 inhibition had any effect on formalin response for either sex. Conclusion This study provides novel behavioural evidence for the male-specific role of PKCι/λ and downstream target p62/GluA1, highlighting the potential influence of ongoing afferent input. The sexually divergent pathways underlying persistent pain are shown here to converge at the interaction between NSF and the GluA2 subunit of the AMPA receptor. Although this interaction is thought to be downstream of PKMζ in males, these findings and previous work suggest that females may rely on a factor independent of atypical PKCs for the maintenance of spinal nociceptive sensitization.
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Affiliation(s)
- Nicole C George
- 1 Alan Edwards Centre for Research on Pain, Montreal, QC, Canada.,2 Integrated Program in Neuroscience, Montreal, QC, Canada.,3 Department of Anesthesia, McGill University, Montreal, QC, Canada
| | - André Laferrière
- 1 Alan Edwards Centre for Research on Pain, Montreal, QC, Canada.,3 Department of Anesthesia, McGill University, Montreal, QC, Canada
| | - Terence J Coderre
- 1 Alan Edwards Centre for Research on Pain, Montreal, QC, Canada.,2 Integrated Program in Neuroscience, Montreal, QC, Canada.,3 Department of Anesthesia, McGill University, Montreal, QC, Canada
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Ketamine Alleviates Fear Generalization Through GluN2B-BDNF Signaling in Mice. Neurosci Bull 2019; 36:153-164. [PMID: 31444653 DOI: 10.1007/s12264-019-00422-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 06/21/2019] [Indexed: 02/02/2023] Open
Abstract
Fear memories are critical for survival. Nevertheless, over-generalization of these memories, depicted by a failure to distinguish threats from safe stimuli, is typical in stress-related disorders. Previous studies have supported a protective role of ketamine against stress-induced depressive behavior. However, the effect of ketamine on fear generalization remains unclear. In this study, we investigated the effects of ketamine on fear generalization in a fear-generalized mouse model. The mice were given a single sub-anesthetic dose of ketamine (30 mg/kg, i.p.) 1 h before, 1 week before, immediately after, or 22 h after fear conditioning. The behavioral measure of fear (indicated by freezing level) and synaptic protein expression in the basolateral amygdala (BLA) and inferior-limbic pre-frontal cortex (IL-PFC) of mice were examined. We found that only ketamine administered 22 h after fear conditioning significantly decreased the fear generalization, and the effect was dose-dependent and lasted for at least 2 weeks. The fear-generalized mice showed a lower level of brain-derived neurotrophic factor (BDNF) and a higher level of GluN2B protein in the BLA and IL-PFC, and this was reversed by a single administration of ketamine. Moreover, the GluN2B antagonist ifenprodil decreased the fear generalization when infused into the IL-PFC, but had no effect when infused into the BLA. Infusion of ANA-12 (an antagonist of the BDNF receptor TrkB) into the BLA or IL-PFC blocked the effect of ketamine on fear generalization. These findings support the conclusion that a single dose of ketamine administered 22 h after fear conditioning alleviates the fear memory generalization in mice and the GluN2B-related BDNF signaling pathway plays an important role in the alleviation of fear generalization.
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23
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Kaldun JC, Sprecher SG. Initiated by CREB: Resolving Gene Regulatory Programs in Learning and Memory. Bioessays 2019; 41:e1900045. [DOI: 10.1002/bies.201900045] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 04/29/2019] [Indexed: 12/29/2022]
Affiliation(s)
- Jenifer C. Kaldun
- Department of BiologyUniversity of Fribourg1700 Fribourg Switzerland
| | - Simon G. Sprecher
- Department of BiologyUniversity of Fribourg1700 Fribourg Switzerland
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Protein Kinase C Lambda Mediates Acid-Sensing Ion Channel 1a-Dependent Cortical Synaptic Plasticity and Pain Hypersensitivity. J Neurosci 2019; 39:5773-5793. [PMID: 31101759 DOI: 10.1523/jneurosci.0213-19.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 05/12/2019] [Accepted: 05/14/2019] [Indexed: 02/08/2023] Open
Abstract
Chronic pain is a serious debilitating disease for which effective treatment is still lacking. Acid-sensing ion channel 1a (ASIC1a) has been implicated in nociceptive processing at both peripheral and spinal neurons. However, whether ASIC1a also contributes to pain perception at the supraspinal level remains elusive. Here, we report that ASIC1a in ACC is required for thermal and mechanical hypersensitivity associated with chronic pain. ACC-specific genetic deletion or pharmacological blockade of ASIC1a reduced the probability of cortical LTP induction and attenuated inflammatory thermal hyperalgesia and mechanical allodynia in male mice. Using cell type-specific manipulations, we demonstrate that ASIC1a in excitatory neurons of ACC is a major player in cortical LTP and pain behavior. Mechanistically, we show that ASIC1a tuned pain-related cortical plasticity through protein kinase C λ-mediated increase of membrane trafficking of AMPAR subunit GluA1 in ACC. Importantly, postapplication of ASIC1a inhibitors in ACC reversed previously established nociceptive hypersensitivity in both chronic inflammatory pain and neuropathic pain models. These results suggest that ASIC1a critically contributes to a higher level of pain processing through synaptic potentiation in ACC, which may serve as a promising analgesic target for treatment of chronic pain.SIGNIFICANCE STATEMENT Chronic pain is a debilitating disease that still lacks effective therapy. Ion channels are good candidates for developing new analgesics. Here, we provide several lines of evidence to support an important role of cortically located ASIC1a channel in pain hypersensitivity through promoting long-term synaptic potentiation in the ACC. Our results indicate a promising translational potential of targeting ASIC1a to treat chronic pain.
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O'Reilly KC, Perica MI, Fenton AA. Synaptic plasticity/dysplasticity, process memory and item memory in rodent models of mental dysfunction. Schizophr Res 2019; 207:22-36. [PMID: 30174252 PMCID: PMC6395534 DOI: 10.1016/j.schres.2018.08.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 08/14/2018] [Accepted: 08/14/2018] [Indexed: 12/21/2022]
Abstract
Activity-dependent changes in the effective connection strength of synapses are a fundamental feature of a nervous system. This so-called synaptic plasticity is thought to underlie storage of information in memory and has been hypothesized to be crucial for the effects of cognitive behavioral therapy. Synaptic plasticity stores information in a neural network, creating a trace of neural activity from past experience. The plasticity can also change the behavior of the network so the network can differentially transform/compute information in future activations. We discuss these two related but separable functions of synaptic plasticity; one we call "item memory" as it represents and stores items of information in memory, the other we call "process memory" as it encodes and stores functions such as computations to modify network information processing capabilities. We review evidence of item and process memory operations in behavior and evidence that experience modifies the brain's functional networks. We discuss neurodevelopmental rodent models relevant for understanding mental illness and compare two models in which one model, neonatal ventral hippocampal lesion (NVHL) has beneficial adult outcomes after being exposed to an adolescent cognitive experience that is potentially similar to cognitive behavioral therapy. The other model, gestational day 17 methylazoxymethanol acetate (GD17-MAM), does not benefit from the same adolescent cognitive experience. We propose that process memory is altered by early cognitive experience in NVHL rats but not in GD17-MAM rats, and discuss how dysplasticity factors may contribute to the differential adult outcomes after early cognitive experience in the NVHL and MAM models.
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Affiliation(s)
- Kally C O'Reilly
- Center for Neural Science, New York University, New York, NY 10003, USA.
| | - Maria I Perica
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - André A Fenton
- Center for Neural Science, New York University, New York, NY 10003, USA; Neuroscience Institute at the New York University Langone Medical Center, New York, NY 10016, USA; Department of Physiology & Pharmacology, Robert F. Furchgott Center for Neuroscience, State University of New York, Downstate Medical Center, Brooklyn, NY 11203, USA.
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26
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Smolen P, Baxter DA, Byrne JH. How can memories last for days, years, or a lifetime? Proposed mechanisms for maintaining synaptic potentiation and memory. ACTA ACUST UNITED AC 2019; 26:133-150. [PMID: 30992383 PMCID: PMC6478248 DOI: 10.1101/lm.049395.119] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 03/12/2019] [Indexed: 01/24/2023]
Abstract
With memory encoding reliant on persistent changes in the properties of synapses, a key question is how can memories be maintained from days to months or a lifetime given molecular turnover? It is likely that positive feedback loops are necessary to persistently maintain the strength of synapses that participate in encoding. Such feedback may occur within signal-transduction cascades and/or the regulation of translation, and it may occur within specific subcellular compartments or within neuronal networks. Not surprisingly, numerous positive feedback loops have been proposed. Some posited loops operate at the level of biochemical signal-transduction cascades, such as persistent activation of Ca2+/calmodulin kinase II (CaMKII) or protein kinase Mζ. Another level consists of feedback loops involving transcriptional, epigenetic and translational pathways, and autocrine actions of growth factors such as BDNF. Finally, at the neuronal network level, recurrent reactivation of cell assemblies encoding memories is likely to be essential for late maintenance of memory. These levels are not isolated, but linked by shared components of feedback loops. Here, we review characteristics of some commonly discussed feedback loops proposed to underlie the maintenance of memory and long-term synaptic plasticity, assess evidence for and against their necessity, and suggest experiments that could further delineate the dynamics of these feedback loops. We also discuss crosstalk between proposed loops, and ways in which such interaction can facilitate the rapidity and robustness of memory formation and storage.
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Affiliation(s)
- Paul Smolen
- 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, Texas 77030, USA
| | - Douglas A Baxter
- 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, Texas 77030, USA
| | - John H Byrne
- 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, Texas 77030, USA
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27
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Histone acetylation determines transcription of atypical protein kinases in rat neurons. Sci Rep 2019; 9:4332. [PMID: 30867503 PMCID: PMC6416243 DOI: 10.1038/s41598-019-40823-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 02/11/2019] [Indexed: 01/19/2023] Open
Abstract
It is widely accepted that memory consolidation requires de-novo transcription of memory-related genes. Epigenetic modifications, particularly histone acetylation, may facilitate gene transcription, but their potential molecular targets are poorly characterized. In the current study, we addressed the question of epigenetic control of atypical protein kinases (aPKC) that are critically involved in memory consolidation and maintenance. We examined the patterns of expression of two aPKC genes (Prkci and Prkcz) in rat cultured cortical neurons treated with histone deacetylase inhibitors. Histone hyperacetylation in the promoter region of Prkci gene elicited direct activation of transcriptional machinery, resulting in increased production of PKCλ mRNA. In parallel, histone hyperacetylation in the upstream promoter of Prkcz gene led to appearance of the corresponding PKCζ transcripts that are almost absent in the brain in resting conditions. In contrast, histone hyperacetylation in the downstream promoter of Prkcz gene was accompanied by a decreased expression of the brain-specific PKMζ products. We showed that epigenetically-triggered differential expression of PKMζ and PKCζ mRNA depended on protein synthesis. Summarizing, our results suggest that genes, encoding memory-related aPKC, may represent the molecular targets for epigenetic regulation through posttranslational histone modifications.
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28
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PKMζ Inhibition Disrupts Reconsolidation and Erases Object Recognition Memory. J Neurosci 2019; 39:1828-1841. [PMID: 30622166 DOI: 10.1523/jneurosci.2270-18.2018] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/09/2018] [Accepted: 12/27/2018] [Indexed: 11/21/2022] Open
Abstract
Object recognition memory (ORM) confers the ability to discriminate the familiarity of previously encountered items. Reconsolidation is the process by which reactivated memories become labile and susceptible to modifications. The hippocampus is specifically engaged in reconsolidation to integrate new information into the original ORM through a mechanism involving activation of brain-derived neurotrophic factor (BDNF) signaling and induction of LTP. It is known that BDNF can control LTP maintenance through protein kinase Mζ (PKMζ), an atypical protein kinase C isoform that is thought to sustain memory storage by modulating glutamatergic neurotransmission. However, the potential involvement of PKMζ in ORM reconsolidation has never been studied. Using a novel ORM task combined with pharmacological, biochemical, and electrophysiological tools, we found that hippocampal PKMζ is essential to update ORM through reconsolidation, but not to maintain the inactive recognition memory trace stored over time, in adult male Wistar rats. Our results also indicate that hippocampal PKMζ acts downstream of BDNF and controls AMPAR synaptic insertion to elicit reconsolidation and suggest that blocking PKMζ activity during this process deletes active ORM.SIGNIFICANCE STATEMENT Object recognition memory (ORM) is essential to remember facts and events. Reconsolidation integrates new information into ORM through changes in hippocampal plasticity and brain-derived neurotrophic factor (BDNF) signaling. In turn, BDNF enhances synaptic efficacy through protein kinase Mζ (PKMζ), which might preserve memory. Here, we present evidence that hippocampal PKMζ acts downstream of BDNF to regulate AMPAR recycling during ORM reconsolidation and show that this kinase is essential to update the reactivated recognition memory trace, but not to consolidate or maintain an inactive ORM. We also demonstrate that the amnesia provoked by disrupting ORM reconsolidation through PKMζ inhibition is due to memory erasure and not to retrieval failure.
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29
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Bear MF, Cooke SF, Giese KP, Kaang BK, Kennedy MB, Kim JI, Morris RGM, Park P. In memoriam: John Lisman - commentaries on CaMKII as a memory molecule. Mol Brain 2018; 11:76. [PMID: 30593282 PMCID: PMC6309094 DOI: 10.1186/s13041-018-0419-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 10/24/2018] [Indexed: 11/10/2022] Open
Abstract
Shortly before he died in October 2017, John Lisman submitted an invited review to Molecular Brain on 'Criteria for identifying the molecular basis of the engram (CaMKII, PKMζ)'. John had no opportunity to read the referees' comments, and as a mark of the regard in which he was held by the neuroscience community the Editors decided to publish his review as submitted. This obituary takes the form of a series of commentaries on Lisman's review. At the same time we are publishing as a separate article a longer response by Todd Sacktor and André Fenton entitled 'What does LTP tell us about the roles of CaMKII and PKMζ in memory?' which presents the case for a rival memory molecule, PKMζ.
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Affiliation(s)
- Mark F. Bear
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
| | - Sam F. Cooke
- King’s College London, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, De Crespigny Park, London, SE5 8AF UK
| | - Karl Peter Giese
- King’s College London, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, De Crespigny Park, London, SE5 8AF UK
| | - Bong-Kiun Kaang
- Department of Biological Sciences, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Mary B. Kennedy
- The Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125 USA
| | - Ji-il Kim
- Department of Biological Sciences, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
| | - Richard G. M. Morris
- Laboratory for Cognitive Neuroscience, Centre for Discovery Brain Sciences, Edinburgh Neuroscience, Edinburgh, EH8 9JZ UK
| | - Pojeong Park
- Department of Biological Sciences, Seoul National University, Gwanak-gu, Seoul, Republic of Korea
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30
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What does LTP tell us about the roles of CaMKII and PKMζ in memory? Mol Brain 2018; 11:77. [PMID: 30593289 PMCID: PMC6309091 DOI: 10.1186/s13041-018-0420-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 10/24/2018] [Indexed: 11/18/2022] Open
Abstract
In “Criteria for identifying the molecular basis of the engram (CaMKII, PKMζ),” Lisman proposes that elucidating the mechanism of LTP maintenance is key to understanding memory storage. He suggests three criteria for a maintenance mechanism to evaluate data on CaMKII and PKMζ as memory storage molecules: necessity, occlusion, and erasure. Here we show that when the criteria are tested, the results reveal important differences between the molecules. Inhibiting PKMζ reverses established, protein synthesis-dependent late-LTP, without affecting early-LTP or baseline synaptic transmission. In contrast, blocking CaMKII has two effects: 1) inhibiting CaMKII activity blocks LTP induction but not maintenance, and 2) disrupting CaMKII interactions with NMDARs in the postsynaptic density (PSD) depresses both early-LTP and basal synaptic transmission equivalently. To identify a maintenance mechanism, we propose a fourth criterion — persistence. PKMζ increases for hours during LTP maintenance in hippocampal slices, and for over a month in specific brain regions during long-term memory storage in conditioned animals. In contrast, increased CaMKII activity lasts only minutes following LTP induction, and CaMKII translocation to the PSD in late-LTP or memory has not been reported. Lastly, do the PKMζ and CaMKII models integrate the many other signaling molecules important for LTP? Activity-dependent PKMζ synthesis is regulated by many of the signaling molecules that induce LTP, including CaMKII, providing a plausible mechanism for new gene expression in the persistent phosphorylation by PKMζ maintaining late-LTP and memory. In contrast, CaMKII autophosphorylation and translocation do not appear to require new protein synthesis. Therefore, the cumulative evidence supports a core role for PKMζ in late-LTP and long-term memory maintenance, and separate roles for CaMKII in LTP induction and for the maintenance of postsynaptic structure and synaptic transmission in a mechanism distinct from late-LTP.
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31
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Baltaci SB, Mogulkoc R, Baltaci AK. Molecular Mechanisms of Early and Late LTP. Neurochem Res 2018; 44:281-296. [DOI: 10.1007/s11064-018-2695-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 10/31/2018] [Accepted: 12/04/2018] [Indexed: 12/01/2022]
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Castranio EL, Wolfe CM, Nam KN, Letronne F, Fitz NF, Lefterov I, Koldamova R. ABCA1 haplodeficiency affects the brain transcriptome following traumatic brain injury in mice expressing human APOE isoforms. Acta Neuropathol Commun 2018; 6:69. [PMID: 30049279 PMCID: PMC6062955 DOI: 10.1186/s40478-018-0569-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 07/12/2018] [Indexed: 02/07/2023] Open
Abstract
Expression of human Apolipoprotein E (APOE) modulates the inflammatory response in an isoform specific manner, with APOE4 isoform eliciting a stronger pro-inflammatory response, suggesting a possible mechanism for worse outcome following traumatic brain injury (TBI). APOE lipidation and stability is modulated by ATP-binding cassette transporter A1 (ABCA1), a transmembrane protein that transports lipids and cholesterol onto APOE. We examined the impact of Abca1 deficiency and APOE isoform expression on the response to TBI using 3-months-old, human APOE3+/+ (E3/Abca1+/+) and APOE4+/+ (E4/Abca1+/+) targeted replacement mice, and APOE3+/+ and APOE4+/+ mice with only one functional copy of the Abca1 gene (E3/Abca1+/-; E4/Abca1+/-). TBI-treated mice received a craniotomy followed by a controlled cortical impact (CCI) brain injury in the left hemisphere; sham-treated mice received the same surgical procedure without the impact. We performed RNA-seq using samples from cortices and hippocampi followed by genome-wide differential gene expression analysis. We found that TBI significantly impacted unique transcripts within each group, however, the proportion of unique transcripts was highest in E4/Abca1+/- mice. Additionally, we found that Abca1 haplodeficiency increased the expression of microglia sensome genes among only APOE4 injured mice, a response not seen in injured APOE3 mice, nor in either group of sham-treated mice. To identify gene networks, or modules, correlated to TBI, APOE isoform and Abca1 haplodeficiency, we used weighted gene co-expression network analysis (WGCNA). The module that positively correlated to TBI groups was associated with immune response and featured hub genes that were microglia-specific, including Trem2, Tyrobp, Cd68 and Hexb. The modules positively correlated with APOE4 isoform and negatively to Abca1 haplodeficient mice represented "protein translation" and "oxidation-reduction process", respectively. Our results reveal E4/Abca1+/- TBI mice have a distinct response to injury, and unique gene networks are associated with APOE isoform, Abca1 insufficiency and injury.
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Affiliation(s)
- Emilie L Castranio
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Cody M Wolfe
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Kyong Nyon Nam
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Florent Letronne
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Nicholas F Fitz
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Iliya Lefterov
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, 15261, USA.
| | - Radosveta Koldamova
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, 15261, USA.
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Sajan MP, Hansen BC, Higgs MG, Kahn CR, Braun U, Leitges M, Park CR, Diamond DM, Farese RV. Atypical PKC, PKCλ/ι, activates β-secretase and increases Aβ 1-40/42 and phospho-tau in mouse brain and isolated neuronal cells, and may link hyperinsulinemia and other aPKC activators to development of pathological and memory abnormalities in Alzheimer's disease. Neurobiol Aging 2018; 61:225-237. [PMID: 29032894 PMCID: PMC5705272 DOI: 10.1016/j.neurobiolaging.2017.09.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 08/25/2017] [Accepted: 09/03/2017] [Indexed: 12/31/2022]
Abstract
Hyperinsulinemia activates brain Akt and PKC-λ/ι and increases Aβ1-40/42 and phospho-tau in insulin-resistant animals. Here, we examined underlying mechanisms in mice, neuronal cells, and mouse hippocampal slices. Like Aβ1-40/42, β-secretase activity was increased in insulin-resistant mice and monkeys. In insulin-resistant mice, inhibition of hepatic PKC-λ/ι sufficient to correct hepatic abnormalities and hyperinsulinemia simultaneously reversed increases in Akt, atypical protein kinase C (aPKC), β-secretase, and Aβ1-40/42, and restored acute Akt activation. However, 2 aPKC inhibitors additionally blocked insulin's ability to activate brain PKC-λ/ι and thereby increase β-secretase and Aβ1-40/42. Furthermore, direct blockade of brain aPKC simultaneously corrected an impairment in novel object recognition in high-fat-fed insulin-resistant mice. In neuronal cells and/or mouse hippocampal slices, PKC-ι/λ activation by insulin, metformin, or expression of constitutive PKC-ι provoked increases in β-secretase, Aβ1-40/42, and phospho-thr-231-tau that were blocked by various PKC-λ/ι inhibitors, but not by an Akt inhibitor. PKC-λ/ι provokes increases in brain β-secretase, Aβ1-40/42, and phospho-thr-231-tau. Excessive signaling via PKC-λ/ι may link hyperinsulinemia and other PKC-λ/ι activators to pathological and functional abnormalities in Alzheimer's disease.
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Affiliation(s)
- Mini P Sajan
- Internal Medicine and Research Services, James A. Haley Veterans Medical Center, Tampa, Florida, USA; Department of Internal Medicine, University of South Florida College of Medicine, Tampa, Florida, USA
| | - Barbara C Hansen
- Internal Medicine and Research Services, James A. Haley Veterans Medical Center, Tampa, Florida, USA
| | - Margaret G Higgs
- Internal Medicine and Research Services, James A. Haley Veterans Medical Center, Tampa, Florida, USA
| | - C Ron Kahn
- Joslin Research Foundation, Harvard Medical School, Boston, MA, USA
| | | | | | - Collin R Park
- Departments of Psychology, Molecular Pharmacology and Physiology, Center for Preclinical and Clinical Research on PTSD, University of South Florida, Tampa, Florida, USA
| | - David M Diamond
- Departments of Psychology, Molecular Pharmacology and Physiology, Center for Preclinical and Clinical Research on PTSD, University of South Florida, Tampa, Florida, USA
| | - Robert V Farese
- Internal Medicine and Research Services, James A. Haley Veterans Medical Center, Tampa, Florida, USA; Department of Internal Medicine, University of South Florida College of Medicine, Tampa, Florida, USA.
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Yu NK, Uhm H, Shim J, Choi JH, Bae S, Sacktor TC, Hohng S, Kaang BK. Increased PKMζ activity impedes lateral movement of GluA2-containing AMPA receptors. Mol Brain 2017; 10:56. [PMID: 29202853 PMCID: PMC5716381 DOI: 10.1186/s13041-017-0334-7] [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] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 11/08/2017] [Indexed: 01/19/2023] Open
Abstract
Protein kinase M zeta (PKMζ), a constitutively active, atypical protein kinase C isoform, maintains a high level of expression in the brain after the induction of learning and long-term potentiation (LTP). Further, its overexpression enhances long-term memory and LTP. Thus, multiple lines of evidence suggest a significant role for persistently elevated PKMζ levels in long-term memory. The molecular mechanisms of how synaptic properties are regulated by the increase in PKMζ, however, are still largely unknown. The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor (AMPAR) mediates most of the fast glutamatergic synaptic transmission in the brain and is known to be critical for the expression of synaptic plasticity and memory. Importance of AMPAR trafficking has been implicated in PKMζ-mediated cellular processes, but the detailed mechanisms, particularly in terms of regulation of AMPAR lateral movement, are not well understood. In the current study, using a single-molecule live imaging technique, we report that the overexpression of PKMζ in hippocampal neurons immobilized GluA2-containing AMPARs, highlighting a potential novel mechanism by which PKMζ may regulate memory and synaptic plasticity.
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Affiliation(s)
- Nam-Kyung Yu
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
| | - Heesoo Uhm
- Department of Physics and Astronomy, Seoul National University, Seoul, South Korea.,National Center for Creative Research Initiatives, Seoul National University, Seoul, South Korea.,Institute of Applied Physics, Seoul National University, Seoul, South Korea.,Department of Biophysics and Chemical Biology, Seoul National University, Seoul, South Korea
| | - Jaehoon Shim
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
| | - Jun-Hyeok Choi
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
| | - Sangsu Bae
- Institute of Nano Science and Technology, Hanyang University, Seoul, South Korea
| | - Todd Charlton Sacktor
- Department of Physiology & Pharmacology, SUNY Downstate Medical Center, 450 Clarkson Ave, Brooklyn, NY, 11203, USA.,Department of Anesthesiology, SUNY Downstate Medical Center, 450 Clarkson Ave, Brooklyn, NY, 11203, USA.,Department of Neurology, SUNY Downstate Medical Center, 450 Clarkson Ave, Brooklyn, NY, 11203, USA
| | - Sungchul Hohng
- Department of Physics and Astronomy, Seoul National University, Seoul, South Korea. .,National Center for Creative Research Initiatives, Seoul National University, Seoul, South Korea. .,Institute of Applied Physics, Seoul National University, Seoul, South Korea. .,Department of Biophysics and Chemical Biology, Seoul National University, Seoul, South Korea.
| | - Bong-Kiun Kaang
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea. .,Center for Neuron and Disease, Frontier Institute of Life Science and of Science and Technology, Xi'an Jiaotong University, Xi'an, China.
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Abstract
Elucidating the molecular mechanisms that maintain long-term memory is a fundamental goal of neuroscience. Accumulating evidence suggests that persistent signaling by the atypical protein kinase C (PKC) isoform protein kinase Mζ (PKMζ) might maintain synaptic long-term potentiation (LTP) and long-term memory. However, the role of PKMζ has been challenged by genetic data from PKMζ-knockout mice showing intact LTP and long-term memory. Moreover, the PKMζ inhibitor peptide ζ inhibitory peptide (ZIP) reverses LTP and erases memory in both wild-type and knockout mice. Data from four papers using additional isoform-specific genetic approaches have helped to reconcile these conflicting findings. First, a PKMζ-antisense approach showed that LTP and long-term memory in PKMζ-knockout mice are mediated through a compensatory mechanism that depends on another ZIP-sensitive atypical isoform, PKCι/λ. Second, short hairpin RNAs decreasing the amounts of individual atypical isoforms without inducing compensation disrupted memory in different temporal phases. PKCι/λ knockdown disrupted short-term memory, whereas PKMζ knockdown specifically erased long-term memory. Third, conditional PKCι/λ knockout induced compensation by rapidly activating PKMζ to preserve short-term memory. Fourth, a dominant-negative approach in the model system Aplysia revealed that multiple PKCs form PKMs to sustain different types of long-term synaptic facilitation, with atypical PKM maintaining synaptic plasticity similar to LTP. Thus, under physiological conditions, PKMζ is the principal PKC isoform that maintains LTP and long-term memory. PKCι/λ can compensate for PKMζ, and because other isoforms could also maintain synaptic facilitation, there may be a hierarchy of compensatory mechanisms maintaining memory if PKMζ malfunctions.
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Affiliation(s)
- Todd Charlton Sacktor
- Departments of Physiology & Pharmacology, Anesthesiology, and Neurology, Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, NY 11203, USA.
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, Davis, CA 95615, USA.
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Kinases of eIF2a Switch Translation of mRNA Subset during Neuronal Plasticity. Int J Mol Sci 2017; 18:ijms18102213. [PMID: 29065505 PMCID: PMC5666893 DOI: 10.3390/ijms18102213] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 10/18/2017] [Accepted: 10/19/2017] [Indexed: 12/31/2022] Open
Abstract
Compared to other types of cells, neurons express the largest number of diverse mRNAs, including neuron-specific ones. This mRNA diversity is required for neuronal function, memory storage, maintenance and retrieval. Regulation of translation in neurons is very complicated and involves various proteins. Some proteins, implementing translational control in other cell types, are used by neurons for synaptic plasticity. In this review, we discuss the neuron-specific activity of four kinases: protein kinase R (PKR), PKR-like endoplasmic reticulum kinase (PERK), general control nonderepressible 2 kinase (GCN2), and heme-reguated eIF2α kinase (HRI), the substrate for which is α-subunit of eukaryotic initiation factor 2 (eIF2α). Phosphorylation of eIF2α is necessary for the cell during stress conditions, such as lack of amino acids, energy stress or viral infection. We propose that, during memory formation, neurons use some mechanisms similar to those involved in the cellular stress. The four eIF2α kinases regulate translation of certain mRNAs containing upstream open reading frames (uORFs). These mRNAs encode proteins involved in the processes of long-term potentiation (LTP) or long-term depression (LTD). The review examines some neuronal proteins for which translation regulation by eIF2 was suggested and checked experimentally. Of such proteins, we pay close attention to protein kinase Mζ, which is involved in memory storage and regulated at the translational level.
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Abrams TW. Synaptic Plasticity: Cleaved Kinases and the Specificity of Erasing Traumatic Memories. Curr Biol 2017; 27:R1020-R1023. [PMID: 28950086 DOI: 10.1016/j.cub.2017.07.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
New possibilities for treating posttraumatic stress disorder and anxiety disorders involving abnormal memories are emerging from analysis of persistent protein kinase activation and mechanisms of synapse-specific modification, known as synaptic tagging.
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Affiliation(s)
- Thomas W Abrams
- Department of Pharmacology, Department of Anesthesiology, Program in Neuroscience, University of Maryland School of Medicine, 655 West Baltimore Street, Baltimore, MD 21201, USA.
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Sheng T, Wang S, Qian D, Gao J, Ohno S, Lu W. Learning-Induced Suboptimal Compensation for PKCι/λ Function in Mutant Mice. Cereb Cortex 2017; 27:3284-3293. [DOI: 10.1093/cercor/bhx077] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Indexed: 11/13/2022] Open
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