1
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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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Fenton AA. Remapping revisited: how the hippocampus represents different spaces. Nat Rev Neurosci 2024; 25:428-448. [PMID: 38714834 DOI: 10.1038/s41583-024-00817-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2024] [Indexed: 05/25/2024]
Abstract
The representation of distinct spaces by hippocampal place cells has been linked to changes in their place fields (the locations in the environment where the place cells discharge strongly), a phenomenon that has been termed 'remapping'. Remapping has been assumed to be accompanied by the reorganization of subsecond cofiring relationships among the place cells, potentially maximizing hippocampal information coding capacity. However, several observations challenge this standard view. For example, place cells exhibit mixed selectivity, encode non-positional variables, can have multiple place fields and exhibit unreliable discharge in fixed environments. Furthermore, recent evidence suggests that, when measured at subsecond timescales, the moment-to-moment cofiring of a pair of cells in one environment is remarkably similar in another environment, despite remapping. Here, I propose that remapping is a misnomer for the changes in place fields across environments and suggest instead that internally organized manifold representations of hippocampal activity are actively registered to different environments to enable navigation, promote memory and organize knowledge.
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Affiliation(s)
- André A Fenton
- Center for Neural Science, New York University, New York, NY, USA.
- Neuroscience Institute at the NYU Langone Medical Center, New York, NY, USA.
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3
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Vingan I, Phatarpekar S, Tung VSK, Hernández AI, Evgrafov OV, Alarcon JM. Spatially Resolved Transcriptomic Signatures of Hippocampal Subregions and Arc-Expressing Ensembles in Active Place Avoidance Memory. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.30.573225. [PMID: 38260257 PMCID: PMC10802250 DOI: 10.1101/2023.12.30.573225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The rodent hippocampus is a spatially organized neuronal network that supports the formation of spatial and episodic memories. We conducted bulk RNA sequencing and spatial transcriptomics experiments to measure gene expression changes in the dorsal hippocampus following the recall of active place avoidance (APA) memory. Through bulk RNA sequencing, we examined the gene expression changes following memory recall across the functionally distinct subregions of the dorsal hippocampus. We found that recall induced differentially expressed genes (DEGs) in the CA1 and CA3 hippocampal subregions were enriched with genes involved in synaptic transmission and synaptic plasticity, while DEGs in the dentate gyrus (DG) were enriched with genes involved in energy balance and ribosomal function. Through spatial transcriptomics, we examined gene expression changes following memory recall across an array of spots encompassing putative memory-associated neuronal ensembles marked by the expression of the IEGs Arc, Egr1, and c-Jun. Within samples from both trained and untrained mice, the subpopulations of spatial transcriptomic spots marked by these IEGs were transcriptomically and spatially distinct from one another. DEGs detected between Arc+ and Arc- spots exclusively in the trained mouse were enriched in several memory-related gene ontology terms, including "regulation of synaptic plasticity" and "memory." Our results suggest that APA memory recall is supported by regionalized transcriptomic profiles separating the CA1 and CA3 from the DG, transcriptionally and spatially distinct IEG expressing spatial transcriptomic spots, and biological processes related to synaptic plasticity as a defining the difference between Arc+ and Arc- spatial transcriptomic spots.
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Affiliation(s)
- Isaac Vingan
- School of Graduates Studies, Program in Neural and Behavioral Sciences, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
| | - Shwetha Phatarpekar
- Institute of Genomics in Health, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
| | - Victoria Sook Keng Tung
- School of Graduates Studies, Program in Molecular and Cell Biology, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
| | - A Iván Hernández
- School of Graduates Studies, Program in Neural and Behavioral Sciences, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- Department of Pathology, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- The Robert F. Furchgott Center for Neural & Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
| | - Oleg V Evgrafov
- Institute of Genomics in Health, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- School of Graduates Studies, Program in Molecular and Cell Biology, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- Department of Cell Biology, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Juan Marcos Alarcon
- School of Graduates Studies, Program in Neural and Behavioral Sciences, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- Department of Pathology, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- The Robert F. Furchgott Center for Neural & Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
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4
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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. J Clin Invest 2024; 134:e169064. [PMID: 38299587 PMCID: PMC10836803 DOI: 10.1172/jci169064] [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: 02/16/2023] [Accepted: 11/21/2023] [Indexed: 02/02/2024] Open
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 found that reduced levels of the memory-associated protein KIdney/BRAin (KIBRA) in the brain and increased KIBRA protein levels in cerebrospinal fluid are associated with cognitive impairment and pathological tau levels in disease. We next defined a mechanism for plasticity repair in vulnerable neurons using the C-terminus of the KIBRA protein (CT-KIBRA). We showed that CT-KIBRA restored 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 found that CT-KIBRA stabilized the protein kinase Mζ (PKMζ) to maintain synaptic plasticity and memory despite tau-mediated pathogenesis. Thus, our results distinguished KIBRA both as a biomarker of synapse dysfunction 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, California, USA
| | | | - Lei Yao
- Buck Institute for Research on Aging, Novato, California, USA
| | - Jackson H. Chen
- Buck Institute for Research on Aging, Novato, California, USA
| | - Ivy Wong
- Buck Institute for Research on Aging, Novato, California, USA
| | - Rowan Saloner
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, California, USA
| | - Helen Cifuentes
- Buck Institute for Research on Aging, Novato, California, USA
| | - Alissa L. Nana
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, California, USA
| | - Samah Shah
- Buck Institute for Research on Aging, Novato, California, USA
| | - Yaqiao Li
- Gladstone Institutes, San Francisco, Califoria, USA
| | - David Le
- Gladstone Institutes, San Francisco, Califoria, USA
| | - Salvatore Spina
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, California, USA
| | - Lea T. Grinberg
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, California, USA
- Weill Institute for Neurosciences, Department of Pathology, University of California San Francisco, San Francisco, California, USA
| | - William W. Seeley
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, California, USA
- Weill Institute for Neurosciences, Department of Pathology, University of California San Francisco, San Francisco, California, USA
| | - Joel H. Kramer
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, California, 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, New York, USA
| | | | - Li Gan
- Helen and Robert Appel Alzheimer Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York, USA
| | - Kaitlin B. Casaletto
- Memory and Aging Center, Department of Neurology, University of California San Francisco, San Francisco, California, USA
| | - Tara E. Tracy
- Buck Institute for Research on Aging, Novato, California, USA
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5
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Ko T, Jou C, Grau-Perales AB, Reynders M, Fenton AA, Trauner D. Photoactivated Protein Degrader for Optical Control of Synaptic Function. ACS Chem Neurosci 2023; 14:3704-3713. [PMID: 37712589 PMCID: PMC10557063 DOI: 10.1021/acschemneuro.3c00390] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 08/04/2023] [Indexed: 09/16/2023] Open
Abstract
Hundreds of proteins determine the function of synapses, and synapses define the neuronal circuits that subserve myriad brain, cognitive, and behavioral functions. It is thus necessary to precisely manipulate specific proteins at specific sub-cellular locations and times to elucidate the roles of particular proteins and synapses in brain function. We developed PHOtochemically TArgeting Chimeras (PHOTACs) as a strategy to optically degrade specific proteins with high spatial and temporal precision. PHOTACs are small molecules that, upon wavelength-selective illumination, catalyze ubiquitylation and degradation of target proteins through endogenous proteasomes. Here, we describe the design and chemical properties of a PHOTAC that targets Ca2+/calmodulin-dependent protein kinase II alpha (CaMKIIα), which is abundant and crucial for the baseline synaptic function of excitatory neurons. We validate the PHOTAC strategy, showing that the CaMKIIα-PHOTAC is effective in mouse brain tissue. Light activation of CaMKIIα-PHOTAC removed CaMKIIα from regions of the mouse hippocampus only within 25 μm of the illuminated brain surface. The optically controlled degradation decreases synaptic function within minutes of light activation, measured by the light-initiated attenuation of evoked field excitatory postsynaptic potential (fEPSP) responses to physiological stimulation. The PHOTACs methodology should be broadly applicable to other key proteins implicated in synaptic function, especially for evaluating their precise roles in the maintenance of long-term potentiation and memory within subcellular dendritic domains.
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Affiliation(s)
- Tongil Ko
- Department
of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Department
of Chemistry, New York University, New York, New York 10003, United States
| | - Claudia Jou
- Department
of Psychology, Hunter College, New York, New York 10065, United States
| | | | - Martin Reynders
- Department
of Chemistry, New York University, New York, New York 10003, United States
| | - André A. Fenton
- Center
for Neural Science, New York University, New York, New York 10003, United States
| | - Dirk Trauner
- Department
of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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6
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Fenton AA, Hurtado JR, Broek JAC, Park E, Mishra B. Do Place Cells Dream of Deceptive Moves in a Signaling Game? Neuroscience 2023; 529:129-147. [PMID: 37591330 PMCID: PMC10592151 DOI: 10.1016/j.neuroscience.2023.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 07/27/2023] [Accepted: 08/06/2023] [Indexed: 08/19/2023]
Abstract
We consider the possibility of applying game theory to analysis and modeling of neurobiological systems. Specifically, the basic properties and features of information asymmetric signaling games are considered and discussed as having potential to explain diverse neurobiological phenomena; we focus on neuronal action potential discharge that can represent cognitive variables in memory and purposeful behavior. We begin by arguing that there is a pressing need for conceptual frameworks that can permit analysis and integration of information and explanations across many scales of biological function including gene regulation, molecular and biochemical signaling, cellular and metabolic function, neuronal population, and systems level organization to generate plausible hypotheses across these scales. Developing such integrative frameworks is crucial if we are to understand cognitive functions like learning, memory, and perception. The present work focuses on systems neuroscience organized around the connected brain regions of the entorhinal cortex and hippocampus. These areas are intensely studied in rodent subjects as model neuronal systems that undergo activity-dependent synaptic plasticity to form neuronal circuits and represent memories and spatial knowledge used for purposeful navigation. Examples of cognition-related spatial information in the observed neuronal discharge of hippocampal place cell populations and medial entorhinal head-direction cell populations are used to illustrate possible challenges to information maximization concepts. It may be natural to explain these observations using the ideas and features of information asymmetric signaling games.
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Affiliation(s)
- André A Fenton
- Neurobiology of Cognition Laboratory, Center for Neural Science, New York University, New York, NY, USA; Neuroscience Institute at the NYU Langone Medical Center, New York, NY, USA.
| | - José R Hurtado
- Neurobiology of Cognition Laboratory, Center for Neural Science, New York University, New York, NY, USA
| | - Jantine A C Broek
- Departments of Computer Science and Mathematics, Courant Institute of Mathematical Sciences, New York University, New York, NY, USA
| | - EunHye Park
- Neurobiology of Cognition Laboratory, Center for Neural Science, New York University, New York, NY, USA
| | - Bud Mishra
- Departments of Computer Science and Mathematics, Courant Institute of Mathematical Sciences, New York University, New York, NY, USA; Department of Cell Biology, NYU Langone Medical Center, New York, NY, USA; Simon Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
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7
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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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8
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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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9
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Ko T, Jou C, Grau-Perales A, Reynders M, Fenton A, Trauner D. A Photoactivated Protein Degrader for Optical Control of Synaptic Function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.13.528397. [PMID: 36824807 PMCID: PMC9949324 DOI: 10.1101/2023.02.13.528397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Hundreds of proteins determine the function of synapses, and synapses define the neuronal circuits that subserve myriad brain, cognitive, and behavioral functions. It is thus necessary to precisely manipulate specific proteins at specific sub-cellular locations and times to elucidate the roles of particular proteins and synapses in brain function. We developed PHOtochemically TArgeting Chimeras (PHOTACs) as a strategy to optically degrade specific proteins with high spatial and temporal precision. PHOTACs are small molecules that, upon wavelength-selective illumination, catalyze ubiquitylation and degradation of target proteins through endogenous proteasomes. Here we describe the design and chemical properties of a PHOTAC that targets Ca 2+ /calmodulin-dependent protein kinase II alpha (CaMKIIα), which is abundant and crucial for baseline synaptic function of excitatory neurons. We validate the PHOTAC strategy, showing that the CaMKIIα-PHOTAC is effective in mouse brain tissue. Light activation of CaMKIIα-PHOTAC removed CaMKIIα from regions of the mouse hippocampus only within 25 μm of the illuminated brain surface. The optically-controlled degradation decreases synaptic function within minutes of light activation, measured by the light-initiated attenuation of evoked field excitatory postsynaptic potential (fEPSP) responses to physiological stimulation. The PHOTACs methodology should be broadly applicable to other key proteins implicated in synaptic function, especially for evaluating their precise roles in the maintenance of long-term potentiation and memory within subcellular dendritic domains.
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Affiliation(s)
- T. Ko
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street Philadelphia, PA 19104-6323, USA
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003, USA
| | - C. Jou
- Department of Psychology, Hunter College, 695 Park Avenue, New York, NY, 10065, USA
| | - A.B. Grau-Perales
- Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, USA
| | - M. Reynders
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003, USA
| | - A.A. Fenton
- Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, USA
| | - D. Trauner
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street Philadelphia, PA 19104-6323, USA
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003, USA
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10
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Danchin A, Fenton AA. From Analog to Digital Computing: Is Homo sapiens’ Brain on Its Way to Become a Turing Machine? Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.796413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The abstract basis of modern computation is the formal description of a finite state machine, the Universal Turing Machine, based on manipulation of integers and logic symbols. In this contribution to the discourse on the computer-brain analogy, we discuss the extent to which analog computing, as performed by the mammalian brain, is like and unlike the digital computing of Universal Turing Machines. We begin with ordinary reality being a permanent dialog between continuous and discontinuous worlds. So it is with computing, which can be analog or digital, and is often mixed. The theory behind computers is essentially digital, but efficient simulations of phenomena can be performed by analog devices; indeed, any physical calculation requires implementation in the physical world and is therefore analog to some extent, despite being based on abstract logic and arithmetic. The mammalian brain, comprised of neuronal networks, functions as an analog device and has given rise to artificial neural networks that are implemented as digital algorithms but function as analog models would. Analog constructs compute with the implementation of a variety of feedback and feedforward loops. In contrast, digital algorithms allow the implementation of recursive processes that enable them to generate unparalleled emergent properties. We briefly illustrate how the cortical organization of neurons can integrate signals and make predictions analogically. While we conclude that brains are not digital computers, we speculate on the recent implementation of human writing in the brain as a possible digital path that slowly evolves the brain into a genuine (slow) Turing machine.
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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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Chung A, Jou C, Grau-Perales A, Levy E, Dvorak D, Hussain N, Fenton AA. Cognitive control persistently enhances hippocampal information processing. Nature 2021; 600:484-488. [PMID: 34759316 PMCID: PMC8872635 DOI: 10.1038/s41586-021-04070-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 09/29/2021] [Indexed: 01/30/2023]
Abstract
Could learning that uses cognitive control to judiciously use relevant information while ignoring distractions generally improve brain function, beyond forming explicit memories? According to a neuroplasticity hypothesis for how some cognitive behavioural therapies are effective, cognitive control training (CCT) changes neural circuit information processing1-3. Here we investigated whether CCT persistently alters hippocampal neural circuit function. We show that mice learned and remembered a conditioned place avoidance during CCT that required ignoring irrelevant locations of shock. CCT facilitated learning new tasks in novel environments for several weeks, relative to unconditioned controls and control mice that avoided the same place during reduced distraction. CCT rapidly changes entorhinal cortex-to-dentate gyrus synaptic circuit function, resulting in an excitatory-inhibitory subcircuit change that persists for months. CCT increases inhibition that attenuates the dentate response to medial entorhinal cortical input, and through disinhibition, potentiates the response to strong inputs, pointing to overall signal-to-noise enhancement. These neurobiological findings support the neuroplasticity hypothesis that, as well as storing item-event associations, CCT persistently optimizes neural circuit information processing.
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Affiliation(s)
- Ain Chung
- Center for Neural Science, New York University
| | - Claudia Jou
- Department of Psychology, Hunter College, City University of New York
| | | | - Eliott Levy
- Center for Neural Science, New York University
| | - Dino Dvorak
- Center for Neural Science, New York University
| | | | - André A. Fenton
- Center for Neural Science, New York University,Neuroscience Institute at the NYU Langone Medical Center
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Kjaergaard M, Petersen NC, Sørensen JB, Takeuchi T. Introducing the special issue on "Proteins and Circuits in Memory". Eur J Neurosci 2021; 54:6691-6695. [PMID: 34664317 DOI: 10.1111/ejn.15491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/10/2021] [Accepted: 10/11/2021] [Indexed: 11/30/2022]
Affiliation(s)
- Magnus Kjaergaard
- Nordic EMBL Partnership for Molecular Medicine, The Danish Research Institute for Translational Neuroscience (DANDRITE), Aarhus, Denmark.,Center for Proteins in Memory - PROMEMO, Danish National Research Foundation, Copenhagen, Denmark.,Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Nicolas Caesar Petersen
- Centre for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Tomonori Takeuchi
- Nordic EMBL Partnership for Molecular Medicine, The Danish Research Institute for Translational Neuroscience (DANDRITE), Aarhus, Denmark.,Center for Proteins in Memory - PROMEMO, Danish National Research Foundation, Copenhagen, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
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14
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Fulton SL, Hsieh C, Atkin T, Norris R, Schoenfeld E, Tsokas P, Fenton AA, Sacktor TC, Coplan JD. Lifelong reductions of PKMζ in ventral hippocampus of nonhuman primates exposed to early-life adversity due to unpredictable maternal care. Learn Mem 2021; 28:341-347. [PMID: 34400535 PMCID: PMC8372566 DOI: 10.1101/lm.053468.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 07/20/2021] [Indexed: 01/06/2023]
Abstract
Protein kinase Mζ (PKMζ) maintains long-term potentiation (LTP) and long-term memory through persistent increases in kinase expression. Early-life adversity is a precursor to adult mood and anxiety disorders, in part, through persistent disruption of emotional memory throughout life. Here we subjected 10- to 16-wk-old male bonnet macaques to adversity by a maternal variable-foraging demand paradigm. We then examined PKMζ expression in their ventral hippocampi as 7- to 12-yr-old adults. Quantitative immunohistochemistry reveals decreased PKMζ in dentate gyrus, CA1, and subiculum of subjects who had experienced early-life adversity due to the unpredictability of maternal care. Adult animals with persistent decrements of PKMζ in ventral hippocampus express timid rather than confrontational responses to a human intruder. Persistent down-regulation of PKMζ in the ventral hippocampus might reduce the capacity for emotional memory maintenance and contribute to the long-lasting emotional effects of early-life adversity.
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Affiliation(s)
| | | | | | | | | | - Panayiotis Tsokas
- Department of Physiology and Pharmacology,Department of Anesthesiology, SUNY Downstate Medical Center, Brooklyn, New York 11203, USA
| | - André Antonio Fenton
- Department of Physiology and Pharmacology,Center for Neural Science, New York University, New York, New York 10003, USA,Neuroscience Institute at the NYU Langone Medical Center, New York, New York 10016, USA
| | - Todd Charlton Sacktor
- Department of Physiology and Pharmacology,Department of Anesthesiology, SUNY Downstate Medical Center, Brooklyn, New York 11203, USA,Department of Neurology
| | - Jeremy D. Coplan
- Department of Psychiatry, SUNY Downstate Medical Center, Brooklyn, New York 11203, USA
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