1
|
Wang NS, Marino M, Malinow R. Detecting unitary synaptic events with machine learning. Proc Natl Acad Sci U S A 2024; 121:e2315804121. [PMID: 38294937 PMCID: PMC10861888 DOI: 10.1073/pnas.2315804121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 12/14/2023] [Indexed: 02/02/2024] Open
Abstract
Spontaneously occurring miniature excitatory postsynaptic currents (mEPSCs) are fundamental electrophysiological events produced by quantal vesicular transmitter release at synapses. Their analysis can provide important information regarding pre- and postsynaptic function. However, the small signal relative to recording noise requires expertise and considerable time for their identification. Furthermore, many mEPSCs smaller than ~8 pA are not well resolved (e.g., those produced at distant synapses or synapses with few receptor channels). Here, we describe an automated approach to detect mEPSCs using a machine learning-based tool. This method, which can be easily generalized to other one-dimensional signals, eliminates inter-observer bias, provides an estimate of its sensitivity and specificity and permits reliable detection of small (e.g., 5 pA) spontaneous unitary synaptic events.
Collapse
Affiliation(s)
- Nien-Shao Wang
- Center for Neural Circuits and Behavior, Division of Biology, Department of Neurosciences, University of California at San Diego, La Jolla, CA92093
| | - Marc Marino
- Center for Neural Circuits and Behavior, Division of Biology, Department of Neurosciences, University of California at San Diego, La Jolla, CA92093
| | - Roberto Malinow
- Center for Neural Circuits and Behavior, Division of Biology, Department of Neurosciences, University of California at San Diego, La Jolla, CA92093
| |
Collapse
|
2
|
Monk B, Rajkovic A, Petrus S, Rajkovic A, Gaasterland T, Malinow R. A Machine Learning Method to Identify Genetic Variants Potentially Associated With Alzheimer's Disease. Front Genet 2021; 12:647436. [PMID: 34194466 PMCID: PMC8238203 DOI: 10.3389/fgene.2021.647436] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 04/06/2021] [Indexed: 01/17/2023] Open
Abstract
There is hope that genomic information will assist prediction, treatment, and understanding of Alzheimer's disease (AD). Here, using exome data from ∼10,000 individuals, we explore machine learning neural network (NN) methods to estimate the impact of SNPs (i.e., genetic variants) on AD risk. We develop an NN-based method (netSNP) that identifies hundreds of novel potentially protective or at-risk AD-associated SNPs (along with an effect measure); the majority with frequency under 0.01. For case individuals, the number of "protective" (or "at-risk") netSNP-identified SNPs in their genome correlates positively (or inversely) with their age of AD diagnosis and inversely (or positively) with autopsy neuropathology. The effect measure increases correlations. Simulations suggest our results are not due to genetic linkage, overfitting, or bias introduced by netSNP. These findings suggest that netSNP can identify SNPs associated with AD pathophysiology that may assist with the diagnosis and mechanistic understanding of the disease.
Collapse
Affiliation(s)
- Bradley Monk
- Department of Neurosciences, Center for Neural Circuits and Behavior, School of Medicine, University of California, San Diego, San Diego, CA, United States
- Cognitive Science & Psychology IDP, University of California, San Diego, San Diego, CA, United States
| | - Andrei Rajkovic
- Department of Computer Science, Royal Holloway, University of London, Egham, United Kingdom
| | - Semar Petrus
- Institute for Genomic Medicine, Scripps Institution of Oceanography, University of California, San Diego, San Diego, CA, United States
| | - Aleks Rajkovic
- Department of Pathology, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, San Francisco, CA, United States
| | - Terry Gaasterland
- Institute for Genomic Medicine, Scripps Institution of Oceanography, University of California, San Diego, San Diego, CA, United States
| | - Roberto Malinow
- Department of Neurosciences, Center for Neural Circuits and Behavior, School of Medicine, University of California, San Diego, San Diego, CA, United States
- Section of Neurobiology, Division of Biological Sciences, University of California, San Diego, San Diego, CA, United States
| |
Collapse
|
3
|
Dore K, Carrico Z, Alfonso S, Marino M, Koymans K, Kessels HW, Malinow R. PSD-95 protects synapses from β-amyloid. Cell Rep 2021; 35:109194. [PMID: 34077732 PMCID: PMC8237704 DOI: 10.1016/j.celrep.2021.109194] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 03/16/2021] [Accepted: 05/10/2021] [Indexed: 01/22/2023] Open
Abstract
Beta-amyloid (Aβ) depresses excitatory synapses by a poorly understood mechanism requiring NMDA receptor (NMDAR) function. Here, we show that increased PSD-95, a major synaptic scaffolding molecule, blocks the effects of Aβ on synapses. The protective effect persists in tissue lacking the AMPA receptor subunit GluA1, which prevents the confounding synaptic potentiation by increased PSD-95. Aβ modifies the conformation of the NMDAR C-terminal domain (CTD) and its interaction with protein phosphatase 1 (PP1), producing synaptic weakening. Higher endogenous levels or overexpression of PSD-95 block Aβ-induced effects on the NMDAR CTD conformation, its interaction with PP1, and synaptic weakening. Our results indicate that increased PSD-95 protects synapses from Aβ toxicity, suggesting that low levels of synaptic PSD-95 may be a molecular sign indicating synapse vulnerability to Aβ. Importantly, pharmacological inhibition of its depalmitoylation increases PSD-95 at synapses and rescues deficits caused by Aβ, possibly opening a therapeutic avenue against Alzheimer's disease.
Collapse
Affiliation(s)
- Kim Dore
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California, San Diego, San Diego, CA 92093, USA.
| | - Zachary Carrico
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California, San Diego, San Diego, CA 92093, USA
| | - Stephanie Alfonso
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California, San Diego, San Diego, CA 92093, USA
| | - Marc Marino
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California, San Diego, San Diego, CA 92093, USA
| | - Karin Koymans
- Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, the Netherlands
| | - Helmut W Kessels
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California, San Diego, San Diego, CA 92093, USA; Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, the Netherlands
| | - Roberto Malinow
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California, San Diego, San Diego, CA 92093, USA
| |
Collapse
|
4
|
Klein ME, Younts TJ, Cobo CF, Buxbaum AR, Aow J, Erdjument-Bromage H, Richard S, Malinow R, Neubert TA, Singer RH, Castillo PE, Jordan BA. Sam68 Enables Metabotropic Glutamate Receptor-Dependent LTD in Distal Dendritic Regions of CA1 Hippocampal Neurons. Cell Rep 2020; 29:1789-1799.e6. [PMID: 31722197 PMCID: PMC6871770 DOI: 10.1016/j.celrep.2019.10.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 08/15/2019] [Accepted: 10/08/2019] [Indexed: 12/13/2022] Open
Abstract
The transport and translation of dendritic mRNAs by RNA-binding proteins (RBPs) allows for spatially restricted gene expression in neuronal processes. Although local translation in neuronal dendrites is now well documented, there is little evidence for corresponding effects on local synaptic function. Here, we report that the RBP Sam68 promotes the localization and translation of Arc mRNA preferentially in distal dendrites of rodent hippocampal CA1 pyramidal neurons. Consistent with Arc function in translation-dependent synaptic plasticity, we find that Sam68 knockout (KO) mice display impaired metabotropic glutamate-receptor-dependent long-term depression (mGluR-LTD) and impaired structural plasticity exclusively at distal Schaffer-collateral synapses. Moreover, by using quantitative proteomics, we find that the Sam68 interactome contains numerous regulators of mRNA translation and synaptic function. This work identifies an important player in Arc expression, provides a general framework for Sam68 regulation of protein synthesis, and uncovers a mechanism that enables the precise spatiotemporal expression of long-term plasticity throughout neurons.
Collapse
Affiliation(s)
- Matthew E Klein
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
| | - Thomas J Younts
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
| | - Carmen Freire Cobo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
| | - Adina R Buxbaum
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA; Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego, San Diego, CA 92093, USA
| | - Jonathan Aow
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego, San Diego, CA 92093, USA
| | - Hediye Erdjument-Bromage
- Department of Cell Biology and Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Stéphane Richard
- Segal Cancer Center, Lady Davis Institute for Medical Research and Departments of Oncology and Medicine, McGill University, Montréal, QC H3T 1E2, Canada
| | - Roberto Malinow
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego, San Diego, CA 92093, USA
| | - Thomas A Neubert
- Department of Cell Biology and Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Robert H Singer
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA; Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA; Janelia Research Campus of the Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Pablo E Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
| | - Bryen A Jordan
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA; Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA.
| |
Collapse
|
5
|
Landgraf D, Barandas R, Long J, Proulx C, McCarthy M, Malinow R, Welsh D. The role of disturbed circadian clocks in the development of depression-like behavior and metabolic comorbidity in mice. Eur Psychiatry 2020. [DOI: 10.1016/j.eurpsy.2017.01.721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Major depressive disorder (MDD) is often associated with disturbed circadian rhythms. However, a definitive causal role for functioning circadian clocks in mood regulation has not been established. We stereotactically injected viral vectors encoding short hairpin RNA to knock down expression of the essential clock gene Bmal1 into the brain's master circadian pacemaker, the suprachiasmatic nucleus (SCN). In these SCN-specific Bmal1-knockdown (SCN-Bmal1-KD) mice, circadian rhythms were greatly attenuated in the SCN. In the learned helplessness paradigm, the SCN-Bmal1-KD mice were slower to escape, even before exposure to inescapable stress. They also spent more time immobile in the tail suspension test and less time in the lighted section of a light/dark box. The SCN-Bmal1-KD mice also showed an abnormal circadian pattern of corticosterone, and an attenuated increase of corticosterone in response to stress. Furthermore, they displayed greater weight gain, which is frequently observed in MDD patients. Since the circadian system controls important brain systems that regulate affective, cognitive, and metabolic functions, and neuropsychiatric and metabolic diseases are often correlated with disturbances of circadian rhythms, we hypothesize that dysregulation of circadian clocks plays a central role in metabolic comorbidity in psychiatric disorders. In fact, circadian rhythm disturbances have been linked to individual psychiatric and metabolic disorders, but circadian aspects of such disorders have not been considered previously in an integrated manner. Treating and preventing disturbances of circadian clocks in patients suffering psychiatric and metabolic symptoms may be a central element for therapies targeting both disorders concurrently.Disclosure of interestThe authors have not supplied their declaration of competing interest.
Collapse
|
6
|
Dore K, Malinow R. Elevated PSD-95 Blocks Ion-flux Independent LTD: A Potential New Role for PSD-95 in Synaptic Plasticity. Neuroscience 2020; 456:43-49. [PMID: 32114099 DOI: 10.1016/j.neuroscience.2020.02.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 02/12/2020] [Accepted: 02/14/2020] [Indexed: 10/24/2022]
Abstract
We recently demonstrated that NMDA receptors (NMDARs) are capable of ion-flux independent signaling through conformational change in the NMDAR intracellular domain resulting in long-term depression of synaptic transmission (LTD). Here we show that PSD-95 overexpression blocks agonist induced conformational movement in the NMDAR intracellular domain as well as LTD that is NMDAR-dependent and ion-flux independent. Interestingly, previous studies indicate that overexpressed PSD-95 does not block NMDAR-dependent LTD. These data support a model where ion-flux independent LTD is predominant in young animals, which have synapses with low amounts of PSD-95, whereas only ion flux dependent LTD occurs at more mature synapses, which have more PSD-95 that would block ion-flux independent LTD. These results may reconcile different findings regarding ion-flux independent LTD.
Collapse
Affiliation(s)
- Kim Dore
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego, San Diego, CA 92093, United States.
| | - Roberto Malinow
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego, San Diego, CA 92093, United States
| |
Collapse
|
7
|
Klein ME, Chandra J, Sheriff S, Malinow R. Opioid system is necessary but not sufficient for antidepressive actions of ketamine in rodents. Proc Natl Acad Sci U S A 2020; 117:2656-2662. [PMID: 31941713 PMCID: PMC7007545 DOI: 10.1073/pnas.1916570117] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Slow response to the standard treatment for depression increases suffering and risk of suicide. Ketamine, an N-methyl-d-aspartate (NMDA) receptor antagonist, can rapidly alleviate depressive symptoms and reduce suicidality, possibly by decreasing hyperactivity in the lateral habenula (LHb) brain nucleus. Here we find that in a rat model of human depression, opioid antagonists abolish the ability of ketamine to reduce the depression-like behavioral and LHb hyperactive cellular phenotypes. However, activation of opiate receptors alone is not sufficient to produce ketamine-like effects, nor does ketamine mimic the hedonic effects of an opiate, indicating that the opioid system does not mediate the actions of ketamine but rather is permissive. Thus, ketamine does not act as an opiate but its effects require both NMDA and opiate receptor signaling, suggesting that interactions between these two neurotransmitter systems are necessary to achieve an antidepressant effect.
Collapse
Affiliation(s)
- Matthew E Klein
- Department of Psychiatry, University of California San Diego (UCSD) School of Medicine, San Diego, CA 92093;
- Department of Neurosciences, UCSD School of Medicine, San Diego, CA 92093
- Section of Neurobiology, Division of Biology, UCSD, San Diego, CA 92093
| | - Joshua Chandra
- Department of Neurosciences, UCSD School of Medicine, San Diego, CA 92093
- Section of Neurobiology, Division of Biology, UCSD, San Diego, CA 92093
| | - Salma Sheriff
- Department of Neurosciences, UCSD School of Medicine, San Diego, CA 92093
- Section of Neurobiology, Division of Biology, UCSD, San Diego, CA 92093
| | - Roberto Malinow
- Department of Neurosciences, UCSD School of Medicine, San Diego, CA 92093;
- Section of Neurobiology, Division of Biology, UCSD, San Diego, CA 92093
| |
Collapse
|
8
|
Sapkota K, Dore K, Tang K, Irvine M, Fang G, Burnell ES, Malinow R, Jane DE, Monaghan DT. The NMDA receptor intracellular C-terminal domains reciprocally interact with allosteric modulators. Biochem Pharmacol 2018; 159:140-153. [PMID: 30503374 DOI: 10.1016/j.bcp.2018.11.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 11/28/2018] [Indexed: 11/27/2022]
Abstract
N-methyl-d-aspartate receptors (NMDARs) have multiple prominent roles in CNS function but their excessive or insufficient activity contributes to neuropathological/psychiatric disorders. Consequently, a variety of positive and negative allosteric modulators (PAMs and NAMs, respectively) have recently been developed. Although these modulators bind to extracellular domains, in the present report we find that the NMDAR's intracellular C-terminal domains (CTDs) significantly influence PAM/NAM activity. GluN2 CTD deletion robustly affected NAM and PAM activity with both enhancing and inhibiting effects that were compound-specific and NMDAR subunit-specific. In three cases, individual PAMs became NAMs at specific GluN2-truncated receptors. In contrast to GluN2, GluN1 CTD removal only reduced PAM activity of UBP684 and CIQ, and did not affect NAM activity. Consistent with these findings, agents altering phosphorylation state or intracellular calcium levels displayed receptor-specific and compound-specific effects on PAM activity. It is possible that the GluN2's M4 domain transmits intracellular modulatory signals from the CTD to the M1/M4 channel gating machinery and that this site is a point of convergence in the direct or indirect actions of several PAMs/NAMs thus rendering them sensitive to CTD status. Thus, allosteric modulators are likely to have a marked and varied sensitivity to post-translational modifications, protein-protein associations, and intracellular ions. The interaction between PAM activity and NMDAR CTDs appears reciprocal. GluN1 CTD-deletion eliminated UBP684, but not pregnenolone sulfate (PS), PAM activity. And, in the absence of agonists, UBP684, but not PS, was able to promote movement of fluorescently-tagged GluN1-CTDs. Thus, it may be possible to pharmacologically target NMDAR metabotropic activity in the absence of channel activation.
Collapse
Affiliation(s)
- Kiran Sapkota
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA
| | - Kim Dore
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego, San Diego, CA 92093-0634, USA
| | - Kang Tang
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA
| | - Mark Irvine
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences Building, University Walk, University of Bristol, Bristol BS8 1TD, UK
| | - Guangyu Fang
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences Building, University Walk, University of Bristol, Bristol BS8 1TD, UK
| | - Erica S Burnell
- School of Chemistry, National University of Ireland Galway, Galway H91TK33, Ireland
| | - Roberto Malinow
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego, San Diego, CA 92093-0634, USA
| | - David E Jane
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences Building, University Walk, University of Bristol, Bristol BS8 1TD, UK
| | - Daniel T Monaghan
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5800, USA.
| |
Collapse
|
9
|
Müller MK, Jacobi E, Sakimura K, Malinow R, von Engelhardt J. NMDA receptors mediate synaptic depression, but not spine loss in the dentate gyrus of adult amyloid Beta (Aβ) overexpressing mice. Acta Neuropathol Commun 2018; 6:110. [PMID: 30352630 PMCID: PMC6198500 DOI: 10.1186/s40478-018-0611-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 09/29/2018] [Indexed: 11/25/2022] Open
Abstract
Amyloid beta (Aβ)-mediated synapse dysfunction and spine loss are considered to be early events in Alzheimer’s disease (AD) pathogenesis. N-methyl-D-aspartate receptors (NMDARs) have previously been suggested to play a role for Amyloid beta (Aβ) toxicity. Pharmacological block of NMDAR subunits in cultured neurons and mice suggested that NMDARs containing the GluN2B subunit are necessary for Aβ-mediated changes in synapse number and function in hippocampal neurons. Interestingly, NMDARs undergo a developmental switch from GluN2B- to GluN2A-containing receptors. This indicates different functional roles of NMDARs in young mice compared to older animals. In addition, the lack of pharmacological tools to efficiently dissect the role of NMDARs containing the different subunits complicates the interpretation of their specific role. In order to address this problem and to investigate the specific role for Aβ toxicity of the distinct NMDAR subunits in dentate gyrus granule cells of adult mice, we used conditional knockout mouse lines for the subunits GluN1, GluN2A and GluN2B. Aβ-mediated changes in synaptic function and neuronal anatomy were investigated in several-months old mice with virus-mediated overproduction of Aβ and in 1-year old 5xFAD mice. We found that all three NMDAR subunits contribute to the Aβ-mediated decrease in the number of functional synapses. However, NMDARs are not required for the spine number reduction in dentate gyrus granule cells after chronic Aβ-overproduction in 5xFAD mice. Furthermore, the amplitude of synaptic and extrasynaptic NMDAR-mediated currents was reduced in dentate gyrus granule of 5xFAD mice without changes in current kinetics, suggesting that a redistribution or change in subunit composition of NMDARs does not play a role in mediating Amyloid beta (Aβ) toxicity. Our study indicates that NMDARs are involved in AD pathogenesis by compromising synapse function but not by affecting neuron morphology.
Collapse
|
10
|
Abstract
Robust assays for detecting the effects of elevated concentrations of amyloid-β (Aβ) may facilitate Alzheimer’s disease research. An appropriate assay would be high-throughput and enable identification of drugs and genetic mutations that block the effects of Aβ, potentially leading to treatments for Alzheimer’s disease. We discovered that the commonly used cytomegalovirus (CMV) enhancer/promoter is sensitive to the effects of Aβ. By combining the CMV enhancer/promoter with a fluorescent protein, we created a reporter system that produces changes in intracellular fluorescence in response to Aβ. Using hippocampal neurons, we quantified the ability of a CMV-fluorescent protein recombinant reporter to detect both exogenously applied and overexpressed Aβ. This is the first report of a high-throughput enhancer/promoter-based Aβ detection method. The reporter is able to detect the effects of elevated concentrations of Aβ in a high-throughput fashion, providing a new tool for Alzheimer’s disease research and important knowledge about the commonly used CMV enhancer/promoter.
Collapse
Affiliation(s)
- Zachary M Carrico
- Center for Neural Circuits and Behavior, Departments of Neuroscience and Biology, University of California at San Diego, La Jolla, CA 92093, USA
| | - Geneva Le
- Center for Neural Circuits and Behavior, Departments of Neuroscience and Biology, University of California at San Diego, La Jolla, CA 92093, USA
| | - Roberto Malinow
- Center for Neural Circuits and Behavior, Departments of Neuroscience and Biology, University of California at San Diego, La Jolla, CA 92093, USA
| |
Collapse
|
11
|
Landgraf D, Long JE, Proulx CD, Barandas R, Malinow R, Welsh DK. Genetic Disruption of Circadian Rhythms in the Suprachiasmatic Nucleus Causes Helplessness, Behavioral Despair, and Anxiety-like Behavior in Mice. Biol Psychiatry 2016; 80:827-835. [PMID: 27113500 PMCID: PMC5102810 DOI: 10.1016/j.biopsych.2016.03.1050] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 03/04/2016] [Accepted: 03/04/2016] [Indexed: 11/19/2022]
Abstract
BACKGROUND Major depressive disorder is associated with disturbed circadian rhythms. To investigate the causal relationship between mood disorders and circadian clock disruption, previous studies in animal models have employed light/dark manipulations, global mutations of clock genes, or brain area lesions. However, light can impact mood by noncircadian mechanisms; clock genes have pleiotropic, clock-independent functions; and brain lesions not only disrupt cellular circadian rhythms but also destroy cells and eliminate important neuronal connections, including light reception pathways. Thus, a definitive causal role for functioning circadian clocks in mood regulation has not been established. METHODS We stereotactically injected viral vectors encoding short hairpin RNA to knock down expression of the essential clock gene Bmal1 into the brain's master circadian pacemaker, the suprachiasmatic nucleus (SCN). RESULTS In these SCN-specific Bmal1-knockdown (SCN-Bmal1-KD) mice, circadian rhythms were greatly attenuated in the SCN, while the mice were maintained in a standard light/dark cycle, SCN neurons remained intact, and neuronal connections were undisturbed, including photic inputs. In the learned helplessness paradigm, the SCN-Bmal1-KD mice were slower to escape, even before exposure to inescapable stress. They also spent more time immobile in the tail suspension test and less time in the lighted section of a light/dark box. The SCN-Bmal1-KD mice also showed greater weight gain, an abnormal circadian pattern of corticosterone, and an attenuated increase of corticosterone in response to stress. CONCLUSIONS Disrupting SCN circadian rhythms is sufficient to cause helplessness, behavioral despair, and anxiety-like behavior in mice, establishing SCN-Bmal1-KD mice as a new animal model of depression.
Collapse
Affiliation(s)
- Dominic Landgraf
- Veterans Affairs San Diego Healthcare System, San Diego; Department of Psychiatry and Center for Circadian Biology, University of California, San Diego, La Jolla, California.
| | - Jaimie E Long
- Veterans Affairs San Diego Healthcare System, San Diego; Department of Psychiatry and Center for Circadian Biology, University of California, San Diego, La Jolla, California
| | - Christophe D Proulx
- Department of Neurosciences, University of California, San Diego, La Jolla, California
| | - Rita Barandas
- Veterans Affairs San Diego Healthcare System, San Diego; Department of Psychiatry and Center for Circadian Biology, University of California, San Diego, La Jolla, California; Department of Psychiatry, Hospital de Santa Maria, Centro Hospitalar Lisboa Norte, University of Lisbon, Lisbon, Portugal; Faculty of Medicine, University of Lisbon, Lisbon, Portugal
| | - Roberto Malinow
- Department of Neurosciences, University of California, San Diego, La Jolla, California
| | - David K Welsh
- Veterans Affairs San Diego Healthcare System, San Diego; Department of Psychiatry and Center for Circadian Biology, University of California, San Diego, La Jolla, California
| |
Collapse
|
12
|
Dore K, Aow J, Malinow R. The Emergence of NMDA Receptor Metabotropic Function: Insights from Imaging. Front Synaptic Neurosci 2016; 8:20. [PMID: 27516738 PMCID: PMC4963461 DOI: 10.3389/fnsyn.2016.00020] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/06/2016] [Indexed: 01/19/2023] Open
Abstract
The NMDA receptor (R) participates in many important physiological and pathological processes. For example, its activation is required for both long-term potentiation (LTP) and long-term depression (LTD) of synaptic transmission, cellular models of learning and memory. Furthermore, it may play a role in the actions of amyloid-beta on synapses as well as in the signaling leading to cell death following stroke. Until recently, these processes were thought to be mediated by ion-flux through the receptor. Using a combination of imaging and electrophysiological approaches, ion-flux independent functions of the NMDAR were recently examined. In this review, we will discuss the role of metabotropic NMDAR function in LTD and synaptic dysfunction.
Collapse
Affiliation(s)
- Kim Dore
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego San Diego, CA, USA
| | - Jonathan Aow
- Genome Institute of Singapore Singapore, Singapore
| | - Roberto Malinow
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section for Neurobiology, Division of Biology, University of California at San Diego San Diego, CA, USA
| |
Collapse
|
13
|
Alfonso SI, Callender JA, Hooli B, Antal CE, Mullin K, Sherman MA, Lesné SE, Leitges M, Newton AC, Tanzi RE, Malinow R. Gain-of-function mutations in protein kinase Cα (PKCα) may promote synaptic defects in Alzheimer's disease. Sci Signal 2016; 9:ra47. [PMID: 27165780 DOI: 10.1126/scisignal.aaf6209] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Alzheimer's disease (AD) is a progressive dementia disorder characterized by synaptic degeneration and amyloid-β (Aβ) accumulation in the brain. Through whole-genome sequencing of 1345 individuals from 410 families with late-onset AD (LOAD), we identified three highly penetrant variants in PRKCA, the gene that encodes protein kinase Cα (PKCα), in five of the families. All three variants linked with LOAD displayed increased catalytic activity relative to wild-type PKCα as assessed in live-cell imaging experiments using a genetically encoded PKC activity reporter. Deleting PRKCA in mice or adding PKC antagonists to mouse hippocampal slices infected with a virus expressing the Aβ precursor CT100 revealed that PKCα was required for the reduced synaptic activity caused by Aβ. In PRKCA(-/-) neurons expressing CT100, introduction of PKCα, but not PKCα lacking a PDZ interaction moiety, rescued synaptic depression, suggesting that a scaffolding interaction bringing PKCα to the synapse is required for its mediation of the effects of Aβ. Thus, enhanced PKCα activity may contribute to AD, possibly by mediating the actions of Aβ on synapses. In contrast, reduced PKCα activity is implicated in cancer. Hence, these findings reinforce the importance of maintaining a careful balance in the activity of this enzyme.
Collapse
Affiliation(s)
- Stephanie I Alfonso
- Department of Neurosciences and Division of Biology, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Julia A Callender
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA. Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Basavaraj Hooli
- Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Corina E Antal
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA. Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kristina Mullin
- Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Mathew A Sherman
- Department of Neuroscience, N. Bud Grossman Center for Memory Research and Care, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN 55414, USA
| | - Sylvain E Lesné
- Department of Neuroscience, N. Bud Grossman Center for Memory Research and Care, and Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN 55414, USA
| | - Michael Leitges
- Biotechnology Centre of Oslo, University of Oslo, Oslo 0317, Norway
| | - Alexandra C Newton
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Rudolph E Tanzi
- Genetics and Aging Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA.
| | - Roberto Malinow
- Department of Neurosciences and Division of Biology, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA.
| |
Collapse
|
14
|
Tsai LCL, Xie L, Dore K, Xie L, Del Rio JC, King CC, Martinez-Ariza G, Hulme C, Malinow R, Bourne PE, Newton AC. Zeta Inhibitory Peptide Disrupts Electrostatic Interactions That Maintain Atypical Protein Kinase C in Its Active Conformation on the Scaffold p62. J Biol Chem 2015; 290:21845-56. [PMID: 26187466 DOI: 10.1074/jbc.m115.676221] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Indexed: 11/06/2022] Open
Abstract
Atypical protein kinase C (aPKC) enzymes signal on protein scaffolds, yet how they are maintained in an active conformation on scaffolds is unclear. A myristoylated peptide based on the autoinhibitory pseudosubstrate fragment of the atypical PKCζ, zeta inhibitory peptide (ZIP), has been extensively used to inhibit aPKC activity; however, we have previously shown that ZIP does not inhibit the catalytic activity of aPKC isozymes in cells (Wu-Zhang, A. X., Schramm, C. L., Nabavi, S., Malinow, R., and Newton, A. C. (2012) J. Biol. Chem. 287, 12879-12885). Here we sought to identify a bona fide target of ZIP and, in so doing, unveiled a novel mechanism by which aPKCs are maintained in an active conformation on a protein scaffold. Specifically, we used protein-protein interaction network analysis, structural modeling, and protein-protein docking to predict that ZIP binds an acidic surface on the Phox and Bem1 (PB1) domain of p62, an interaction validated by peptide array analysis. Using a genetically encoded reporter for PKC activity fused to the p62 scaffold, we show that ZIP inhibits the activity of wild-type aPKC, but not a construct lacking the pseudosubstrate. These data support a model in which the pseudosubstrate of aPKCs is tethered to the acidic surface on p62, locking aPKC in an open, signaling-competent conformation. ZIP competes for binding to the acidic surface, resulting in displacement of the pseudosubstrate of aPKC and re-engagement in the substrate-binding cavity. This study not only identifies a cellular target for ZIP, but also unveils a novel mechanism by which scaffolded aPKC is maintained in an active conformation.
Collapse
Affiliation(s)
| | - Lei Xie
- the Department of Computer Science, Hunter College, the City University of New York, New York, New York 10065
| | | | - Li Xie
- Skaggs School of Pharmacy, and
| | | | - Charles C King
- Pediatric Diabetes Research Center, University of California San Diego, La Jolla, California 92093
| | - Guillermo Martinez-Ariza
- the Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721, and
| | - Christopher Hulme
- the Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721, and
| | | | - Philip E Bourne
- the Office of the Director, the National Institutes of Health, Bethesda, Maryland 20892
| | | |
Collapse
|
15
|
Alfonso S, Kessels HW, Banos CC, Chan TR, Lin ET, Kumaravel G, Scannevin RH, Rhodes KJ, Huganir R, Guckian KM, Dunah AW, Malinow R. Synapto-depressive effects of amyloid beta require PICK1. Eur J Neurosci 2014; 39:1225-33. [PMID: 24713001 DOI: 10.1111/ejn.12499] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 12/27/2013] [Accepted: 01/02/2014] [Indexed: 11/30/2022]
Abstract
Amyloid beta (Aβ), a key component in the pathophysiology of Alzheimer's disease, is thought to target excitatory synapses early in the disease. However, the mechanism by which Aβ weakens synapses is not well understood. Here we showed that the PDZ domain protein, protein interacting with C kinase 1 (PICK1), was required for Aβ to weaken synapses. In mice lacking PICK1, elevations of Aβ failed to depress synaptic transmission in cultured brain slices. In dissociated cultured neurons, Aβ failed to reduce surface α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit 2, a subunit of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors that binds with PICK1 through a PDZ ligand-domain interaction. Lastly, a novel small molecule (BIO922) discovered through structure-based drug design that targets the specific interactions between GluA2 and PICK1 blocked the effects of Aβ on synapses and surface receptors. We concluded that GluA2-PICK1 interactions are a key component of the effects of Aβ on synapses.
Collapse
Affiliation(s)
- Stephanie Alfonso
- Center for Neural Circuits and Behavior, Departments of Neuroscience and Biology, University of California at San Diego, La Jolla, CA, 92093, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Shabel SJ, Proulx CD, Piriz J, Malinow R. Mood regulation. GABA/glutamate co-release controls habenula output and is modified by antidepressant treatment. Science 2014; 345:1494-8. [PMID: 25237099 DOI: 10.1126/science.1250469] [Citation(s) in RCA: 243] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The lateral habenula (LHb), a key regulator of monoaminergic brain regions, is activated by negatively valenced events. Its hyperactivity is associated with depression. Although enhanced excitatory input to the LHb has been linked to depression, little is known about inhibitory transmission. We discovered that γ-aminobutyric acid (GABA) is co-released with its functional opponent, glutamate, from long-range basal ganglia inputs (which signal negative events) to limit LHb activity in rodents. At this synapse, the balance of GABA/glutamate signaling is shifted toward reduced GABA in a model of depression and increased GABA by antidepressant treatment. GABA and glutamate co-release therefore controls LHb activity, and regulation of this form of transmission may be important for determining the effect of negative life events on mood and behavior.
Collapse
Affiliation(s)
- Steven J Shabel
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section of Neurobiology, Division of Biology, University of California at San Diego, San Diego, CA, USA.
| | - Christophe D Proulx
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section of Neurobiology, Division of Biology, University of California at San Diego, San Diego, CA, USA
| | - Joaquin Piriz
- Grupo de Neurociencia de Sistemas, Instituto de Fisiología y Biofísica Houssay (CONICET-UBA), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Roberto Malinow
- Center for Neural Circuits and Behavior, Department of Neuroscience and Section of Neurobiology, Division of Biology, University of California at San Diego, San Diego, CA, USA
| |
Collapse
|
17
|
Miyazaki T, Takase K, Nakajima W, Tada H, Ohya D, Sano A, Goto T, Hirase H, Malinow R, Takahashi T. Disrupted cortical function underlies behavior dysfunction due to social isolation. J Clin Invest 2014. [DOI: 10.1172/jci76901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
18
|
Viger ML, Sheng W, Doré K, Alhasan AH, Carling CJ, Lux J, de Gracia Lux C, Grossman M, Malinow R, Almutairi A. Near-infrared-induced heating of confined water in polymeric particles for efficient payload release. ACS Nano 2014; 8:4815-26. [PMID: 24717072 PMCID: PMC4046803 DOI: 10.1021/nn500702g] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 03/31/2014] [Indexed: 05/14/2023]
Abstract
Near-infrared (NIR) light-triggered release from polymeric capsules could make a major impact on biological research by enabling remote and spatiotemporal control over the release of encapsulated cargo. The few existing mechanisms for NIR-triggered release have not been widely applied because they require custom synthesis of designer polymers, high-powered lasers to drive inefficient two-photon processes, and/or coencapsulation of bulky inorganic particles. In search of a simpler mechanism, we found that exposure to laser light resonant with the vibrational absorption of water (980 nm) in the NIR region can induce release of payloads encapsulated in particles made from inherently non-photo-responsive polymers. We hypothesize that confined water pockets present in hydrated polymer particles absorb electromagnetic energy and transfer it to the polymer matrix, inducing a thermal phase change. In this study, we show that this simple and highly universal strategy enables instantaneous and controlled release of payloads in aqueous environments as well as in living cells using both pulsed and continuous wavelength lasers without significant heating of the surrounding aqueous solution.
Collapse
Affiliation(s)
- Mathieu L. Viger
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Department of Mechanical and Aerospace Engineering, Materials Science and Engineering Program, Center for Neural Circuits and Behavior, Division of Biology, Department of Neuroscience and Section of Neurobiology, Department of Chemistry and Biochemistry, and KACST−UCSD Center of Excellence in Nanomedicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0600, United States
| | - Wangzhong Sheng
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Department of Mechanical and Aerospace Engineering, Materials Science and Engineering Program, Center for Neural Circuits and Behavior, Division of Biology, Department of Neuroscience and Section of Neurobiology, Department of Chemistry and Biochemistry, and KACST−UCSD Center of Excellence in Nanomedicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0600, United States
| | - Kim Doré
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Department of Mechanical and Aerospace Engineering, Materials Science and Engineering Program, Center for Neural Circuits and Behavior, Division of Biology, Department of Neuroscience and Section of Neurobiology, Department of Chemistry and Biochemistry, and KACST−UCSD Center of Excellence in Nanomedicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0600, United States
| | - Ali H. Alhasan
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Department of Mechanical and Aerospace Engineering, Materials Science and Engineering Program, Center for Neural Circuits and Behavior, Division of Biology, Department of Neuroscience and Section of Neurobiology, Department of Chemistry and Biochemistry, and KACST−UCSD Center of Excellence in Nanomedicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0600, United States
| | - Carl-Johan Carling
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Department of Mechanical and Aerospace Engineering, Materials Science and Engineering Program, Center for Neural Circuits and Behavior, Division of Biology, Department of Neuroscience and Section of Neurobiology, Department of Chemistry and Biochemistry, and KACST−UCSD Center of Excellence in Nanomedicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0600, United States
| | - Jacques Lux
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Department of Mechanical and Aerospace Engineering, Materials Science and Engineering Program, Center for Neural Circuits and Behavior, Division of Biology, Department of Neuroscience and Section of Neurobiology, Department of Chemistry and Biochemistry, and KACST−UCSD Center of Excellence in Nanomedicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0600, United States
| | - Caroline de Gracia Lux
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Department of Mechanical and Aerospace Engineering, Materials Science and Engineering Program, Center for Neural Circuits and Behavior, Division of Biology, Department of Neuroscience and Section of Neurobiology, Department of Chemistry and Biochemistry, and KACST−UCSD Center of Excellence in Nanomedicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0600, United States
| | - Madeleine Grossman
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Department of Mechanical and Aerospace Engineering, Materials Science and Engineering Program, Center for Neural Circuits and Behavior, Division of Biology, Department of Neuroscience and Section of Neurobiology, Department of Chemistry and Biochemistry, and KACST−UCSD Center of Excellence in Nanomedicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0600, United States
| | - Roberto Malinow
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Department of Mechanical and Aerospace Engineering, Materials Science and Engineering Program, Center for Neural Circuits and Behavior, Division of Biology, Department of Neuroscience and Section of Neurobiology, Department of Chemistry and Biochemistry, and KACST−UCSD Center of Excellence in Nanomedicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0600, United States
| | - Adah Almutairi
- Skaggs School of Pharmacy and Pharmaceutical Sciences, Department of Mechanical and Aerospace Engineering, Materials Science and Engineering Program, Center for Neural Circuits and Behavior, Division of Biology, Department of Neuroscience and Section of Neurobiology, Department of Chemistry and Biochemistry, and KACST−UCSD Center of Excellence in Nanomedicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0600, United States
| |
Collapse
|
19
|
Shabel SJ, Murphy RT, Malinow R. Negative learning bias is associated with risk aversion in a genetic animal model of depression. Front Hum Neurosci 2014; 8:1. [PMID: 24474914 PMCID: PMC3893716 DOI: 10.3389/fnhum.2014.00001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 01/02/2014] [Indexed: 11/13/2022] Open
Abstract
The lateral habenula (LHb) is activated by aversive stimuli and the omission of reward, inhibited by rewarding stimuli and is hyperactive in helpless rats—an animal model of depression. Here we test the hypothesis that congenital learned helpless (cLH) rats are more sensitive to decreases in reward size and/or less sensitive to increases in reward than wild-type (WT) control rats. Consistent with the hypothesis, we found that cLH rats were slower to switch preference between two responses after a small upshift in reward size on one of the responses but faster to switch their preference after a small downshift in reward size. cLH rats were also more risk-averse than WT rats—they chose a response delivering a constant amount of reward (“safe” response) more often than a response delivering a variable amount of reward (“risky” response) compared to WT rats. Interestingly, the level of bias toward negative events was associated with the rat's level of risk aversion when compared across individual rats. cLH rats also showed impaired appetitive Pavlovian conditioning but more accurate responding in a two-choice sensory discrimination task. These results are consistent with a negative learning bias and risk aversion in cLH rats, suggesting abnormal processing of rewarding and aversive events in the LHb of cLH rats.
Collapse
Affiliation(s)
- Steven J Shabel
- Section of Neurobiology, Department of Neuroscience and Division of Biology, Center for Neural Circuits and Behavior, University of California at San Diego La Jolla, CA, USA
| | - Ryan T Murphy
- Section of Neurobiology, Department of Neuroscience and Division of Biology, Center for Neural Circuits and Behavior, University of California at San Diego La Jolla, CA, USA
| | - Roberto Malinow
- Section of Neurobiology, Department of Neuroscience and Division of Biology, Center for Neural Circuits and Behavior, University of California at San Diego La Jolla, CA, USA
| |
Collapse
|
20
|
Nabavi S, Fox R, Alfonso S, Aow J, Malinow R. GluA1 trafficking and metabotropic NMDA: addressing results from other laboratories inconsistent with ours. Philos Trans R Soc Lond B Biol Sci 2013; 369:20130145. [PMID: 24298147 DOI: 10.1098/rstb.2013.0145] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We have previously shown that when over-expressed in neurons, green fluorescent protein (GFP) tagged GluA1 (GluA1-GFP) delivery into synapses is dependent on plasticity. A recent study suggests that GluA1 over-expression leads to its incorporation into the synapse, in the absence of additional long-term potentiation-like manipulations. It is possible that a GFP tag was responsible for the difference. Using rectification index as a measure of synaptic delivery of GluA1, we found no difference in the synaptic delivery of GluA1-GFP versus untagged GluA1. We recently published a study showing that while D-APV blocks NMDAr-dependent long-term depression (LTD), MK-801 and 7-chloro kynurenate (7CK) fail to block LTD. We propose a metabotropic function for the NMDA receptor in LTD induction. In contrast to our observations, recent unpublished data suggest that the above antagonists are equally effective in blocking LTD. We noticed different methodology in their study. Here, we show that their methodology has complex effects on synaptic transmission. Therefore, it is not possible to conclude that 7CK is effective in blocking LTD from their type of experiment.
Collapse
Affiliation(s)
- Sadegh Nabavi
- Department of Neurosciences, University of California, San Diego, , La Jolla, CA 92093, USA
| | | | | | | | | |
Collapse
|
21
|
Lin JY, Sann SB, Zhou K, Nabavi S, Proulx CD, Malinow R, Jin Y, Tsien RY. Optogenetic inhibition of synaptic release with chromophore-assisted light inactivation (CALI). Neuron 2013; 79:241-53. [PMID: 23889931 DOI: 10.1016/j.neuron.2013.05.022] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/15/2013] [Indexed: 12/18/2022]
Abstract
Optogenetic techniques provide effective ways of manipulating the functions of selected neurons with light. In the current study, we engineered an optogenetic technique that directly inhibits neurotransmitter release. We used a genetically encoded singlet oxygen generator, miniSOG, to conduct chromophore assisted light inactivation (CALI) of synaptic proteins. Fusions of miniSOG to VAMP2 and synaptophysin enabled disruption of presynaptic vesicular release upon illumination with blue light. In cultured neurons and hippocampal organotypic slices, synaptic release was reduced up to 100%. Such inhibition lasted >1 hr and had minimal effects on membrane electrical properties. When miniSOG-VAMP2 was expressed panneuronally in Caenorhabditis elegans, movement of the worms was reduced after illumination, and paralysis was often observed. The movement of the worms recovered overnight. We name this technique Inhibition of Synapses with CALI (InSynC). InSynC is a powerful way to silence genetically specified synapses with light in a spatially and temporally precise manner.
Collapse
Affiliation(s)
- John Y Lin
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093-0647, USA.
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Abstract
The lateral habenula (LHb) has recently emerged as a key brain region in the pathophysiology of depression. However, the molecular mechanism by which LHb becomes hyperactive in depression remains unknown. Through a quantitative proteomic screen, we found that expression of the β form of calcium/calmodulin-dependent protein kinase type II (βCaMΚΙΙ) was significantly up-regulated in the LHb of animal models of depression and down-regulated by antidepressants. Increasing β-, but not α-, CaMKII in the LHb strongly enhanced the synaptic efficacy and spike output of LHb neurons and was sufficient to produce profound depressive symptoms, including anhedonia and behavioral despair. Down-regulation of βCaMKII levels, blocking its activity or its target molecule the glutamate receptor GluR1 reversed the depressive symptoms. These results identify βCaMKII as a powerful regulator of LHb neuron function and a key molecular determinant of depression.
Collapse
Affiliation(s)
- Kun Li
- Institute of Neuroscience and State Key laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, P.R. China
- Graduate School of Chinese Academy of Sciences, Shanghai 200031, P.R. China
| | - Tao Zhou
- Institute of Neuroscience and State Key laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, P.R. China
- Graduate School of Chinese Academy of Sciences, Shanghai 200031, P.R. China
| | - Lujian Liao
- The Scripps Research Institute, Department of Molecular and Cellular Neurobiology, La Jolla, CA, 92037, USA
| | - Zhongfei Yang
- Institute of Neuroscience and State Key laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, P.R. China
| | - Catherine Wong
- The Scripps Research Institute, Department of Molecular and Cellular Neurobiology, La Jolla, CA, 92037, USA
| | - Fritz Henn
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, New York 11724, USA
| | - Roberto Malinow
- University of California at San Diego, La Jolla, CA, 92093, USA
| | - John R. Yates
- The Scripps Research Institute, Department of Molecular and Cellular Neurobiology, La Jolla, CA, 92037, USA
| | - Hailan Hu
- Institute of Neuroscience and State Key laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, P.R. China
| |
Collapse
|
23
|
Abstract
The mechanisms by which β-amyloid (Aβ), a peptide fragment believed to contribute to Alzheimer's disease, leads to synaptic deficits are not known. Here we find that elevated oligomeric Aβ requires ion flux-independent function of NMDA receptors (NMDARs) to produce synaptic depression. Aβ activates this metabotropic NMDAR function on GluN2B-containing NMDARs but not on those containing GluN2A. Furthermore, oligomeric Aβ leads to a selective loss of synaptic GluN2B responses, effecting a switch in subunit composition from GluN2B to GluN2A, a process normally observed during development. Our results suggest that conformational changes of the NMDAR, and not ion flow through its channel, are required for Aβ to produce synaptic depression and a switch in NMDAR composition. This Aβ-induced signaling mediated by alterations in GluN2B conformation may be a target for therapeutic intervention of Alzheimer's disease.
Collapse
Affiliation(s)
- Helmut W. Kessels
- Center for Neural Circuits and Behavior, Departments of Neuroscience and Biology, University of California at San Diego, La Jolla, CA 92093; and
- Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, 1105 BA, Amsterdam, The Netherlands
| | - Sadegh Nabavi
- Center for Neural Circuits and Behavior, Departments of Neuroscience and Biology, University of California at San Diego, La Jolla, CA 92093; and
| | - Roberto Malinow
- Center for Neural Circuits and Behavior, Departments of Neuroscience and Biology, University of California at San Diego, La Jolla, CA 92093; and
| |
Collapse
|
24
|
|
25
|
Miyazaki T, Takase K, Nakajima W, Tada H, Ohya D, Sano A, Goto T, Hirase H, Malinow R, Takahashi T. Disrupted cortical function underlies behavior dysfunction due to social isolation. J Clin Invest 2012; 122:2690-701. [PMID: 22706303 DOI: 10.1172/jci63060] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 05/09/2012] [Indexed: 01/21/2023] Open
Abstract
Stressful events during early childhood can have a profound lifelong influence on emotional and cognitive behaviors. However, the mechanisms by which stress affects neonatal brain circuit formation are poorly understood. Here, we show that neonatal social isolation disrupts molecular, cellular, and circuit developmental processes, leading to behavioral dysfunction. Neonatal isolation prevented long-term potentiation and experience-dependent synaptic trafficking of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors normally occurring during circuit formation in the rodent barrel cortex. This inhibition of AMPA receptor trafficking was mediated by an increase of the stress glucocorticoid hormone and was associated with reduced calcium/calmodulin-dependent protein kinase type II (CaMKII) signaling, resulting in attenuated whisker sensitivity at the cortex. These effects led to defects in whisker-dependent behavior in juvenile animals. These results indicate that neonatal social isolation alters neuronal plasticity mechanisms and perturbs the initial establishment of a normal cortical circuit, which potentially explains the long-lasting behavioral effects of neonatal stress.
Collapse
Affiliation(s)
- Tomoyuki Miyazaki
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Schramm CL, Wu-Zhang AX, Nabavi S, Xie L, Xie L, Bourne PE, Malinow R, Newton AC. Discrepancies in purified and cellular PKMζ inhibition profiles invalidate its proposed role as a mediator of memory. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.768.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Cicely L Schramm
- Department of PharmacologyUniversity of CaliforniaSan Diego, La JollaCA
| | - Alyssa X Wu-Zhang
- Department of PharmacologyUniversity of CaliforniaSan Diego, La JollaCA
- Biomedical Sciences Graduate ProgramUniversity of CaliforniaSan Diego, La JollaCA
| | - Sadegh Nabavi
- Department of NeurosciencesUniversity of CaliforniaSan Diego, La JollaCA
| | - Lei Xie
- Skaggs School of Pharmacy and Pharmaceutical SciencesUniversity of CaliforniaSan Diego, La JollaCA
- Department of Computer ScienceHunter CollegeThe City University of New YorkNew YorkNY
| | - Li Xie
- Skaggs School of Pharmacy and Pharmaceutical SciencesUniversity of CaliforniaSan Diego, La JollaCA
| | - Philip E Bourne
- Department of PharmacologyUniversity of CaliforniaSan Diego, La JollaCA
- Skaggs School of Pharmacy and Pharmaceutical SciencesUniversity of CaliforniaSan Diego, La JollaCA
| | - Roberto Malinow
- Department of NeurosciencesUniversity of CaliforniaSan Diego, La JollaCA
| | | |
Collapse
|
27
|
Wu-Zhang AX, Schramm CL, Nabavi S, Malinow R, Newton AC. Cellular pharmacology of protein kinase Mζ (PKMζ) contrasts with its in vitro profile: implications for PKMζ as a mediator of memory. J Biol Chem 2012; 287:12879-85. [PMID: 22378786 DOI: 10.1074/jbc.m112.357244] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A number of recent studies have used pharmacological inhibitors to establish a role for protein kinase Mζ (PKMζ) in synaptic plasticity and memory. These studies use zeta inhibitory peptide (ZIP) and chelerythrine as inhibitors of PKMζ to block long term potentiation and memory; staurosporine is used as a negative control to show that a nonspecific kinase inhibitor does not block long term potentiation and memory. Here, we show that neither ZIP nor chelerythrine inhibits PKMζ in cultured cells or brain slices. In contrast, staurosporine does block PKMζ activity in cells and brain slices by inhibiting its upstream phosphoinositide-dependent kinase-1. These studies demonstrate that the effectiveness of drugs against purified PKMζ may not be indicative of their specificity in the more complex environment of the cell and suggest that PKMζ is unlikely to be the mediator of synaptic plasticity or memory.
Collapse
Affiliation(s)
- Alyssa X Wu-Zhang
- Department of Pharmacology, University of California San Diego, La Jolla, California 92093, USA
| | | | | | | | | |
Collapse
|
28
|
Abstract
Synapses in the brain are continuously modified by experience, but the mechanisms are poorly understood. In vitro and theoretical studies suggest threshold-lowering interactions between nearby synapses that favor clustering of synaptic plasticity within a dendritic branch. Here, a fluorescently tagged AMPA receptor-based optical approach was developed permitting detection of single-synapse plasticity in mouse cortex. Sensory experience preferentially produced synaptic potentiation onto nearby dendritic synapses. Such clustering was significantly reduced by expression of a phospho-mutant AMPA receptor that is insensitive to threshold-lowering modulation for plasticity-driven synaptic incorporation. In contrast to experience, sensory deprivation caused homeostatic synaptic enhancement globally on dendrites. Clustered synaptic potentiation produced by experience could bind behaviorally relevant information onto dendritic subcompartments; global synaptic upscaling by deprivation could equally sensitize all dendritic regions for future synaptic input.
Collapse
Affiliation(s)
- Hiroshi Makino
- Center for Neural Circuits and Behavior, Section of Neurobiology, Division of Biology and Department of Neuroscience, University of California, San Diego, La Jolla, CA 92093, USA
| | | |
Collapse
|
29
|
Miyazaki T, Kunii M, Tada H, Sano A, Kuroiwa Y, Goto T, Malinow R, Takahashi T. Developmental AMPA receptor subunit specificity during experience-driven synaptic plasticity in the rat barrel cortex. Brain Res 2011; 1435:1-7. [PMID: 22197698 DOI: 10.1016/j.brainres.2011.11.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 11/11/2011] [Indexed: 11/26/2022]
Abstract
During early postnatal brain development, experience-driven delivery of AMPA receptors to synapses participates in the initial organization of cortical function. By combining virus-mediated in vivo gene delivery with in vitro whole cell recordings, we identified a subunit-specific developmental program of experience-driven AMPA receptor delivery to synapses in rat barrel cortex. We expressed green fluorescent protein (GFP)-tagged AMPA receptors (GFP-GluR1, or GFP-GluR4) into layer 2/3 pyramidal neurons at two distinct developmental periods, postnatal day (P)8-P10 and P12-P14. Two days after viral infection, acute brain slices were prepared, and synaptic transmission from layer 4 to layer 2/3 was analyzed by whole cell recordings. We found that whisker experience drives GluR4 but not GluR1 into these synapses early in postnatal development (P8-P10). However, at P12-14, GluR1 but not GluR4 is delivered into synapses by whisker experience. This precise developmental plan suggests unique plasticity properties endowed in different AMPA receptor subunits which shape the initial experience-driven organization of cortical function.
Collapse
Affiliation(s)
- Tomoyuki Miyazaki
- Yokohama City University Graduate School of Medicine, Department of Physiology, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Malinow R. New developments on the role of NMDA receptors in Alzheimer's disease. Curr Opin Neurobiol 2011; 22:559-63. [PMID: 21962484 DOI: 10.1016/j.conb.2011.09.001] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 09/02/2011] [Accepted: 09/11/2011] [Indexed: 12/13/2022]
Abstract
Since the initial findings that NMDA receptors play important roles in cellular models of learning as well as neurotoxicity, abnormal function of this receptor has been considered a potential mechanism in the pathophysiology underlying Alzheimer's disease. Treatment of Alzheimer's disease with an NMDA receptor antagonist began several years ago, with some limited success. More recent mechanistic studies have examined the role of NMDA receptors in the synaptic effects of beta amyloid (Aβ).
Collapse
Affiliation(s)
- Roberto Malinow
- Center for Neural Circuits and Behavior, Department of Neuroscience, University of California at San Diego, La Jolla, CA 92093, USA.
| |
Collapse
|
31
|
Midthune B, Malinow R, Koo E. P3‐226: Elimination of APP caspase cleavage site D664 attenuates Aβ‐mediated synaptic depression. Alzheimers Dement 2011. [DOI: 10.1016/j.jalz.2011.05.1668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Brea Midthune
- University of CaliforniaLa JollaSan DiegoCaliforniaUnited States
| | - Roberto Malinow
- University of CaliforniaLa JollaSan DiegoCaliforniaUnited States
| | - Edward Koo
- University of CaliforniaLa JollaSan DiegoCaliforniaUnited States
| |
Collapse
|
32
|
|
33
|
Kessels HW, Nguyen LN, Nabavi S, Malinow R. The prion protein as a receptor for amyloid-beta. Nature 2010; 466:E3-4; discussion E4-5. [PMID: 20703260 DOI: 10.1038/nature09217] [Citation(s) in RCA: 224] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 04/01/2010] [Indexed: 11/09/2022]
Abstract
Increased levels of brain amyloid-beta, a secreted peptide cleavage product of amyloid precursor protein (APP), is believed to be critical in the aetiology of Alzheimer's disease. Increased amyloid-beta can cause synaptic depression, reduce the number of spine protrusions (that is, sites of synaptic contacts) and block long-term synaptic potentiation (LTP), a form of synaptic plasticity; however, the receptor through which amyloid-beta produces these synaptic perturbations has remained elusive. Laurén et al. suggested that binding between oligomeric amyloid-beta (a form of amyloid-beta thought to be most active) and the cellular prion protein (PrP(C)) is necessary for synaptic perturbations. Here we show that PrP(C) is not required for amyloid-beta-induced synaptic depression, reduction in spine density, or blockade of LTP; our results indicate that amyloid-beta-mediated synaptic defects do not require PrP(c).
Collapse
Affiliation(s)
- Helmut W Kessels
- Center for Neural Circuits and Behavior, 9500 Gilman Drive 0634, University of California at San Diego, La Jolla, California 92093, USA
| | | | | | | |
Collapse
|
34
|
Malinow R, Hayashi Y, Maletic-Savatic M, Zaman SH, Poncer JC, Shi SH, Esteban JA, Osten P, Seidenman K. Introduction of green fluorescent protein (GFP) into hippocampal neurons through viral infection. Cold Spring Harb Protoc 2010; 2010:pdb.prot5406. [PMID: 20360360 DOI: 10.1101/pdb.prot5406] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Expression of green fluorescent protein (GFP), its more fluorescent mutant forms (e.g., EGFP [enhanced GFP]), or their fusion protein derivatives, affords a number of informative possibilities in cellular neuroscience. EGFP is a soluble protein and appears to be homogeneously distributed within the cytosol of neurons when expressed. Thus, it reveals the structure of the neuron, including the cell body, and axonal and dendritic arbors. It is also sufficiently bright to reveal detailed structures such as axonal boutons and dendritic spines. When expressed as a fusion protein, EGFP can provide information about the distribution characteristics of the proteins within neurons. Furthermore, during single-cell electrophysiological studies, such expression can direct the investigator to record from a cell carrying a foreign gene. In this protocol, we describe the use of the Sindbis pseudovirus expression system to deliver GFP to neurons. Sindbis is a member of the alphaviruses, which are plus-stranded RNA viruses. This protocol uses the DH(26S) strain, which preferentially infects neurons over glia (50:1). Two infection methods are given: one for dissociated hippocampal cultured neurons and one for organotypic hippocampal slices.
Collapse
|
35
|
Makino H, Malinow R. AMPA receptor incorporation into synapses during LTP: the role of lateral movement and exocytosis. Neuron 2009; 64:381-90. [PMID: 19914186 DOI: 10.1016/j.neuron.2009.08.035] [Citation(s) in RCA: 353] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2008] [Revised: 08/22/2009] [Accepted: 08/25/2009] [Indexed: 01/17/2023]
Abstract
The regulated trafficking of AMPA receptors (AMPARs) to synapses is thought to underlie the enhanced transmission in long-term potentiation (LTP), a cellular model of memory. However, there is controversy regarding the nonsynaptic site, either on the surface or intracellularly, from which AMPARs move into synapses during LTP. Using recombinant surface-fluorescent receptors in organotypic rat hippocampal slices, we show that the majority of AMPARs incorporated into synapses during LTP is from lateral diffusion of spine surface receptors containing GluR1, an AMPAR subunit. Following synaptic potentiation, AMPARs in intracellular pools containing GluR1 are driven to the surface primarily on dendrites. These exocytosed receptors likely serve to replenish the local extrasynaptic pool available for subsequent bouts of plasticity. These results clarify the role of intracellular and surface AMPARs during synaptic plasticity.
Collapse
Affiliation(s)
- Hiroshi Makino
- Department of Neurosciences, Division of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | | |
Collapse
|
36
|
Nadif Kasri N, Nakano-Kobayashi A, Malinow R, Li B, Van Aelst L. The Rho-linked mental retardation protein oligophrenin-1 controls synapse maturation and plasticity by stabilizing AMPA receptors. Genes Dev 2009; 23:1289-302. [PMID: 19487570 DOI: 10.1101/gad.1783809] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Oligophrenin-1 (OPHN1) encodes a Rho-GTPase-activating protein (Rho-GAP) whose loss of function has been associated with X-linked mental retardation (MR). The pathophysiological role of OPHN1, however, remains poorly understood. Here we show that OPHN1 through its Rho-GAP activity plays a critical role in the activity-dependent maturation and plasticity of excitatory synapses by controlling their structural and functional stability. Synaptic activity through NMDA receptor activation drives OPHN1 into dendritic spines, where it forms a complex with AMPA receptors, and selectively enhances AMPA-receptor-mediated synaptic transmission and spine size by stabilizing synaptic AMPA receptors. Consequently, decreased or defective OPHN1 signaling prevents glutamatergic synapse maturation and causes loss of synaptic structure, function, and plasticity. These results imply that normal activity-driven glutamatergic synapse development is impaired by perturbation of OPHN1 function. Thus, our findings link genetic deficits in OPHN1 to glutamatergic dysfunction and suggest that defects in early circuitry development are an important contributory factor to this form of MR.
Collapse
Affiliation(s)
- Nael Nadif Kasri
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | | | | | | | | |
Collapse
|
37
|
Abstract
The ability to change behavior likely depends on the selective strengthening and weakening of brain synapses. The cellular models of synaptic plasticity, long-term potentiation (LTP) and depression (LTD) of synaptic strength, can be expressed by the synaptic insertion or removal of AMPA receptors (AMPARs), respectively. We here present an overview of studies that have used animal models to show that such AMPAR trafficking underlies several experience-driven phenomena-from neuronal circuit formation to the modification of behavior. We argue that monitoring and manipulating synaptic AMPAR trafficking represents an attractive means to study cognitive function and dysfunction in animal models.
Collapse
Affiliation(s)
- Helmut W Kessels
- Department of Neuroscience, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0634, USA.
| | | |
Collapse
|
38
|
Malgaroli A, Malinow R, Schulman H, Tsien RW. Persistent signalling and changes in presynaptic function in long-term potentiation. Ciba Found Symp 2007; 164:176-91; discussion 192-6. [PMID: 1327679 DOI: 10.1002/9780470514207.ch12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Long-term potentiation (LTP) is an example of a persistent change in synaptic function in the mammalian brain, thought to be essential for learning and memory. At the synapse between hippocampal CA3 and CA1 neurons LTP is induced by a Ca2+ influx through glutamate receptors of the NMDA (N-methyl-D-aspartate) type (see Collingridge et al 1992, this volume). How does a rise in [Ca2+]i lead to enhancement of synaptic function? We have tested the popular hypothesis that Ca2+ acts via a Ca(2+)-dependent protein kinase. We found that long-lasting synaptic enhancement was prevented by prior intracellular injection of potent and selective inhibitory peptide blockers of either protein kinase C (PKC) or Ca2+/calmodulin-dependent protein kinase II (CaMKII), such as PKC(19-31) or CaMKII(273-302), but not by control peptides. Evidently, activity of both PKC and CaMKII is somehow necessary for the postsynaptic induction of LTP. To determine if these kinases are also involved in the expression of LTP, we impaled cells with microelectrodes containing protein kinase inhibitors after LTP had already been induced. Strikingly, established LTP was not suppressed by a combination of PKC and CaMKII blocking peptides, or by intracellular postsynaptic H-7. However, established LTP remained sensitive to bath application of H-7. Thus, the persistent signal may be a persistent kinase, but if so, the kinase cannot be accessed within the postsynaptic cell. Evidence for a presynaptic locus of expression comes from our studies of quantal synaptic transmission under whole-cell voltage clamp. We find changes in synaptic variability expected to result from enhanced presynaptic transmitter release, but little or no increase in quantal size. Furthermore, miniature synaptic currents in hippocampal cultures are increased in frequency but not amplitude as a result of a glutamate-driven postsynaptic induction. The combination of postsynaptic induction and presynaptic expression necessitates a retrograde signal from the postsynaptic cell to the presynaptic terminal.
Collapse
Affiliation(s)
- A Malgaroli
- Department of Molecular and Cellular Physiology, Stanford University Medical Center, CA 94305-5425
| | | | | | | |
Collapse
|
39
|
Li B, Woo RS, Mei L, Malinow R. The neuregulin-1 receptor erbB4 controls glutamatergic synapse maturation and plasticity. Neuron 2007; 54:583-97. [PMID: 17521571 PMCID: PMC2031848 DOI: 10.1016/j.neuron.2007.03.028] [Citation(s) in RCA: 273] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Revised: 02/15/2007] [Accepted: 03/29/2007] [Indexed: 11/16/2022]
Abstract
Neuregulin-1 (NRG1) signaling participates in numerous neurodevelopmental processes. Through linkage analysis, nrg1 has been associated with schizophrenia, although its pathophysiological role is not understood. The prevailing models of schizophrenia invoke hypofunction of the glutamatergic synapse and defects in early development of hippocampal-cortical circuitry. Here, we show that the erbB4 receptor, as a postsynaptic target of NRG1, plays a key role in activity-dependent maturation and plasticity of excitatory synaptic structure and function. Synaptic activity leads to the activation and recruitment of erbB4 into the synapse. Overexpressed erbB4 selectively enhances AMPA synaptic currents and increases dendritic spine size. Preventing NRG1/erbB4 signaling destabilizes synaptic AMPA receptors and leads to loss of synaptic NMDA currents and spines. Our results indicate that normal activity-driven glutamatergic synapse development is impaired by genetic deficits in NRG1/erbB4 signaling leading to glutamatergic hypofunction. These findings link proposed effectors in schizophrenia: NRG1/erbB4 signaling perturbation, neurodevelopmental deficit, and glutamatergic hypofunction.
Collapse
Affiliation(s)
- Bo Li
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Ran-Sook Woo
- Program of Developmental Neurobiology and Department of Neurology, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912, USA
| | - Lin Mei
- Program of Developmental Neurobiology and Department of Neurology, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, Georgia 30912, USA
| | - Roberto Malinow
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
- * Corresponding Author, e-mail:
| |
Collapse
|
40
|
Abstract
The activity-dependent regulation of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors and the stabilization of synapses are critical to synaptic development and plasticity. One candidate molecule implicated in maturation, synaptic strengthening, and plasticity is PSD-95. Here we find that acute knockdown of PSD-95 in brain slice cultures by RNAi arrests the normal development of synaptic structure and function that is driven by spontaneous activity. Surprisingly, PSD-95 is not necessary for the induction and early expression of long-term potentiation (LTP). However, knockdown of PSD-95 leads to smaller increases in spine size after chemically induced LTP. Furthermore, although at this age spine turnover is normally low and LTP produces a transient increase, in cells with reduced PSD-95 spine turnover is high and remains increased after LTP. Taken together, our data support a model in which appropriate levels of PSD-95 are required for activity-dependent synapse stabilization after initial phases of synaptic potentiation.
Collapse
Affiliation(s)
- Ingrid Ehrlich
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
| | | | | | | |
Collapse
|
41
|
Hsieh H, Boehm J, Sato C, Iwatsubo T, Tomita T, Sisodia S, Malinow R. AMPAR removal underlies Abeta-induced synaptic depression and dendritic spine loss. Neuron 2007; 52:831-43. [PMID: 17145504 PMCID: PMC1850952 DOI: 10.1016/j.neuron.2006.10.035] [Citation(s) in RCA: 796] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 06/10/2006] [Accepted: 10/26/2006] [Indexed: 12/15/2022]
Abstract
Beta amyloid (Abeta), a peptide generated from the amyloid precursor protein (APP) by neurons, is widely believed to underlie the pathophysiology of Alzheimer's disease. Recent studies indicate that this peptide can drive loss of surface AMPA and NMDA type glutamate receptors. We now show that Abeta employs signaling pathways of long-term depression (LTD) to drive endocytosis of synaptic AMPA receptors. Synaptic removal of AMPA receptors is necessary and sufficient to produce loss of dendritic spines and synaptic NMDA responses. Our studies indicate the central role played by AMPA receptor trafficking in Abeta-induced modification of synaptic structure and function.
Collapse
Affiliation(s)
- Helen Hsieh
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | | | | | | | | | | | | |
Collapse
|
42
|
Affiliation(s)
- Charles Kopec
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
| | | |
Collapse
|
43
|
Rial Verde EM, Lee-Osbourne J, Worley PF, Malinow R, Cline HT. Increased expression of the immediate-early gene arc/arg3.1 reduces AMPA receptor-mediated synaptic transmission. Neuron 2006; 52:461-74. [PMID: 17088212 PMCID: PMC3951199 DOI: 10.1016/j.neuron.2006.09.031] [Citation(s) in RCA: 315] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Revised: 06/24/2005] [Accepted: 08/18/2006] [Indexed: 11/19/2022]
Abstract
Arc/Arg3.1 is an immediate-early gene whose expression levels are increased by strong synaptic activation, including synapse-strengthening activity patterns. Arc/Arg3.1 mRNA is transported to activated dendritic regions, conferring the distribution of Arc/Arg3.1 protein both temporal correlation with the inducing stimulus and spatial specificity. Here, we investigate the effect of increased Arc/Arg3.1 levels on synaptic transmission. Surprisingly, Arc/Arg3.1 reduces the amplitude of synaptic currents mediated by AMPA-type glutamate receptors (AMPARs). This effect is prevented by RNAi knockdown of Arc/Arg3.1, by deleting a region of Arc/Arg3.1 known to interact with endophilin 3 or by blocking clathrin-coated endocytosis of AMPARs. In the hippocampal slice, Arc/Arg3.1 results in removal of AMPARs composed of GluR2 and GluR3 subunits (GluR2/3). Finally, Arc/Arg3.1 expression occludes NMDAR-dependent long-term depression. Our results demonstrate that Arc/Arg3.1 reduces the number of GluR2/3 receptors leading to a decrease in AMPAR-mediated synaptic currents, consistent with a role in the homeostatic regulation of synaptic strength.
Collapse
Affiliation(s)
- Emiliano M. Rial Verde
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
| | - Jane Lee-Osbourne
- Graduate Program in Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11790
| | | | - Roberto Malinow
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
| | - Hollis T. Cline
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
| |
Collapse
|
44
|
Abstract
The regulated trafficking of GluR1 contributes significantly to synaptic plasticity, but studies addressing the function of the GluR1 C-terminal PDZ-ligand domain in this process have produced conflicting results. Here, we resolve this conflict by showing that apparently similar C-terminal mutations of the GluR1 PDZ-ligand domain result in opposite physiological phenotypes during activity- and CamKII-induced synaptic plasticity.
Collapse
Affiliation(s)
- Jannic Boehm
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | | | | | | |
Collapse
|
45
|
Kopec CD, Kessels HWHG, Bush DEA, Cain CK, LeDoux JE, Malinow R. A robust automated method to analyze rodent motion during fear conditioning. Neuropharmacology 2006; 52:228-33. [PMID: 16926033 DOI: 10.1016/j.neuropharm.2006.07.028] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Revised: 07/07/2006] [Accepted: 07/17/2006] [Indexed: 10/24/2022]
Abstract
A central question in the study of LTP has been to determine what role it plays in memory formation and storage. One valuable form of learning for addressing this issue is associative fear conditioning. In this paradigm an animal learns to associate a tone and shock, such that subsequent presentation of a tone evokes a fear response (freezing behavior). Recent studies indicate that overlapping cellular processes underlie fear conditioning and LTP. The fear response has generally been scored manually which is both labor-intensive and subject to potential artifacts such as inconsistent or biased results. Here we describe a simple automated method that provides unbiased and rapid analysis of animal motion. We show that measured motion, in units termed significant motion pixels (SMPs), is both linear and robust over a wide range of animal speeds and detection thresholds and scores freezing in a quantitatively similar manner to trained human observers. By comparing the frequency distribution of motion during baseline periods and to the response to fox urine (which causes unconditioned fear), we suggest that freezing and non-freezing are distinct behaviors. Finally, we show how this algorithm can be applied to a fear conditioning paradigm yielding information on long and short-term associative memory as well as habituation. This automated analysis of fear conditioning will permit a more rapid and accurate assessment of the role of LTP in memory.
Collapse
Affiliation(s)
- Charles D Kopec
- Cold Spring Harbor Laboratory, Jones Building, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
| | | | | | | | | | | |
Collapse
|
46
|
Boehm J, Kang MG, Johnson RC, Esteban J, Huganir RL, Malinow R. Synaptic Incorporation of AMPA Receptors during LTP Is Controlled by a PKC Phosphorylation Site on GluR1. Neuron 2006; 51:213-25. [PMID: 16846856 DOI: 10.1016/j.neuron.2006.06.013] [Citation(s) in RCA: 282] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Revised: 05/08/2006] [Accepted: 06/16/2006] [Indexed: 11/17/2022]
Abstract
Incorporation of GluR1-containing AMPA receptors into synapses is essential to several forms of neural plasticity, including long-term potentiation (LTP). Numerous signaling pathways that trigger this process have been identified, but the direct modifications of GluR1 that control its incorporation into synapses are unclear. Here, we show that phosphorylation of GluR1 by PKC at a highly conserved serine 818 residue is increased during LTP and critical for LTP expression. GluR1 is phosphorylated by PKC at this site in vitro and in vivo. In addition, acute phosphorylation at GluR1 S818 by PKC, as well as a phosphomimetic mutation, promotes GluR1 synaptic incorporation. Conversely, preventing GluR1 S818 phosphorylation reduces LTP and blocks PKC-driven synaptic incorporation of GluR1. We conclude that the phosphorylation of GluR1 S818 by PKC is a critical event in the plasticity-driven synaptic incorporation of AMPA receptors.
Collapse
Affiliation(s)
- Jannic Boehm
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, New York 11724, USA
| | | | | | | | | | | |
Collapse
|
47
|
Kopec CD, Li B, Wei W, Boehm J, Malinow R. Glutamate receptor exocytosis and spine enlargement during chemically induced long-term potentiation. J Neurosci 2006; 26:2000-9. [PMID: 16481433 PMCID: PMC6674938 DOI: 10.1523/jneurosci.3918-05.2006] [Citation(s) in RCA: 358] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The changes in synaptic morphology and receptor content that underlie neural plasticity are poorly understood. Here, we use a pH-sensitive green fluorescent protein to tag recombinant glutamate receptors and monitor their dynamics onto dendritic spine surfaces. We show that chemically induced long-term potentiation (chemLTP) drives robust exocytosis of AMPA receptors. In contrast, the same stimulus produces a small reduction of NMDA receptors from the spine surface. chemLTP produces similar modification of small and large spines. Interestingly, during chemLTP induction, spines increase in volume before accumulation of AMPA receptors on their surface, indicating that distinct mechanisms underlie changes in morphology and receptor content.
Collapse
|
48
|
Abstract
A widely studied example of vertebrate plasticity is LTP (long-term potentiation), the persistent synaptic enhancement that follows a brief period of coinciding pre- and post-synaptic activity. During LTP, different kinases, including CaMKII (calcium/calmodulin-dependent protein kinase II) and protein kinase A, become activated and play critical roles in induction and maintenance of enhanced transmission. Biochemical analyses have revealed several regulated phosphorylation sites in the AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor subunits, GluR1 and GluR4. The regulated insertion of these receptors is a key event in the induction of LTP. Here, we discuss the phosphorylation of GluR1 and GluR4 and its role in receptor delivery and neuronal plasticity.
Collapse
Affiliation(s)
- J Boehm
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | | |
Collapse
|
49
|
Barria A, Malinow R. NMDA Receptor Subunit Composition Controls Synaptic Plasticity by Regulating Binding to CaMKII. Neuron 2005; 48:289-301. [PMID: 16242409 DOI: 10.1016/j.neuron.2005.08.034] [Citation(s) in RCA: 540] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2005] [Revised: 06/30/2005] [Accepted: 08/24/2005] [Indexed: 10/25/2022]
Abstract
Calcium entry through postsynaptic NMDA-Rs and subsequent activation of CaMKII trigger synaptic plasticity in many brain regions. Active CaMKII can bind to NMDA-Rs, but the physiological role of this interaction is not well understood. Here, we test if association between active CaMKII and synaptic NMDA-Rs is required for synaptic plasticity. Switching synaptic NR2B-containing NMDA-Rs that bind CaMKII with high affinity with those containing NR2A, a subunit with low affinity for CaMKII, dramatically reduces LTP. Expression of NR2A with mutations that increase association to active CaMKII recovers LTP. Finally, driving into synapses NR2B with mutations that reduce association to active CaMKII prevents LTP. Spontaneous activity-driven potentiation shows similar results. We conclude that association between active CaMKII and NR2B is required for different forms of synaptic enhancement. The switch from NR2B to NR2A content in synaptic NMDA-Rs normally observed in many brain regions may contribute to reduced plasticity by controlling the binding of active CaMKII.
Collapse
Affiliation(s)
- Andres Barria
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA.
| | | |
Collapse
|
50
|
Abstract
To elucidate molecular, cellular, and circuit changes that occur in the brain during learning, we investigated the role of a glutamate receptor subtype in fear conditioning. In this form of learning, animals associate two stimuli, such as a tone and a shock. Here we report that fear conditioning drives AMPA-type glutamate receptors into the synapse of a large fraction of postsynaptic neurons in the lateral amygdala, a brain structure essential for this learning process. Furthermore, memory was reduced if AMPA receptor synaptic incorporation was blocked in as few as 10 to 20% of lateral amygdala neurons. Thus, the encoding of memories in the lateral amygdala is mediated by AMPA receptor trafficking, is widely distributed, and displays little redundancy.
Collapse
Affiliation(s)
- Simon Rumpel
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | | | | | | |
Collapse
|