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Grünewald B, Wickel J, Hahn N, Rahmati V, Rupp H, Chung HY, Haselmann H, Strauss AS, Schmidl L, Hempel N, Grünewald L, Urbach A, Bauer M, Toyka KV, Blaess M, Claus RA, König R, Geis C. Targeted rescue of synaptic plasticity improves cognitive decline in sepsis-associated encephalopathy. Mol Ther 2024; 32:2113-2129. [PMID: 38788710 DOI: 10.1016/j.ymthe.2024.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 04/02/2024] [Accepted: 05/01/2024] [Indexed: 05/26/2024] Open
Abstract
Sepsis-associated encephalopathy (SAE) is a frequent complication of severe systemic infection resulting in delirium, premature death, and long-term cognitive impairment. We closely mimicked SAE in a murine peritoneal contamination and infection (PCI) model. We found long-lasting synaptic pathology in the hippocampus including defective long-term synaptic plasticity, reduction of mature neuronal dendritic spines, and severely affected excitatory neurotransmission. Genes related to synaptic signaling, including the gene for activity-regulated cytoskeleton-associated protein (Arc/Arg3.1) and members of the transcription-regulatory EGR gene family, were downregulated. At the protein level, ARC expression and mitogen-activated protein kinase signaling in the brain were affected. For targeted rescue we used adeno-associated virus-mediated overexpression of ARC in the hippocampus in vivo. This recovered defective synaptic plasticity and improved memory dysfunction. Using the enriched environment paradigm as a non-invasive rescue intervention, we found improvement of defective long-term potentiation, memory, and anxiety. The beneficial effects of an enriched environment were accompanied by an increase in brain-derived neurotrophic factor (BDNF) and ARC expression in the hippocampus, suggesting that activation of the BDNF-TrkB pathway leads to restoration of the PCI-induced reduction of ARC. Collectively, our findings identify synaptic pathomechanisms underlying SAE and provide a conceptual approach to target SAE-induced synaptic dysfunction with potential therapeutic applications to patients with SAE.
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Affiliation(s)
- Benedikt Grünewald
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Institute of Pathophysiology and Focus Program Translational Neuroscience (FTN), University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany
| | - Jonathan Wickel
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Nina Hahn
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Vahid Rahmati
- Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Hanna Rupp
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Ha-Yeun Chung
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Holger Haselmann
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Anja S Strauss
- Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Lars Schmidl
- Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Nina Hempel
- Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Lena Grünewald
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, University Hospital of Frankfurt, 60528 Frankfurt, Germany
| | - Anja Urbach
- Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Jena Center for Healthy Aging, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Leibniz Institute on Aging, Aging Research Center Jena, Beutenbergstr. 11, 07745 Jena, Germany
| | - Michael Bauer
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Department of Anesthesiology and Intensive Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Klaus V Toyka
- Department of Neurology, University of Würzburg, 97080 Würzburg, Germany
| | - Markus Blaess
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Institute of Precision Medicine, Medical and Life Sciences Faculty, Furtwangen University, 78054 Villingen-Schwenningen, Germany
| | - Ralf A Claus
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Department of Anesthesiology and Intensive Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Rainer König
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Department of Anesthesiology and Intensive Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany
| | - Christian Geis
- Center for Sepsis Control and Care, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; Section Translational Neuroimmunology, Department of Neurology, Jena University Hospital, Am Klinikum 1, 07747 Jena, Germany; German Center for Mental Health (DZP), Center for Intervention and Research on Adaptive and Maladaptive Brain Circuits Underlying Mental Health (C-I-R-C), Jena-Magdeburg-Halle, Jena, Germany.
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2
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Cagnetta R, Lacaille JC, Sonenberg N. Exploration of new space elicits phosphorylation of GluA1(Ser831) and S6K and expression of Arc in the hippocampus in vivo as in long-term potentiation. Mol Brain 2024; 17:35. [PMID: 38858726 PMCID: PMC11165848 DOI: 10.1186/s13041-024-01100-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 05/14/2024] [Indexed: 06/12/2024] Open
Abstract
The brain responds to experience through modulation of synaptic transmission, that is synaptic plasticity. An increase in the strength of synaptic transmission is manifested as long-term potentiation (LTP), while a decrease in the strength of synaptic transmission is expressed as long-term depression (LTD). Most of the studies of synaptic plasticity have been carried out by induction via electrophysiological stimulation. It is largely unknown in which behavioural tasks such synaptic plasticity occurs. Moreover, some stimuli can induce both LTP and LTD, thus making it difficult to separately study the different forms of synaptic plasticity. Two studies have shown that an aversive memory task - inhibitory avoidance learning and contextual fear conditioning - physiologically and selectively induce LTP and an LTP-like molecular change, respectively, in the hippocampus in vivo. Here, we show that a non-aversive behavioural task - exploration of new space - physiologically and selectively elicits a biochemical change in the hippocampus that is a hallmark of LTP. Specifically, we found that exploration of new space induces an increase in the phosphorylation of GluA1(Ser831), without affecting the phosphorylation of GluA1(Ser845), which are biomarkers of early-LTP and not NMDAR-mediated LTD. We also show that exploration of new space engenders the phosphorylation of the translational regulator S6K and the expression of Arc, which are features of electrophysiologically-induced late-LTP in the hippocampus. Therefore, our results show that exploration of new space is a novel non-aversive behavioural paradigm that elicits molecular changes in vivo that are analogous to those occurring during early- and late-LTP, but not during NMDAR-mediated LTD.
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Affiliation(s)
- Roberta Cagnetta
- Department of Cell Biology and Program in Neuroscience, Harvard Medical School, Boston, MA, 02115, USA.
- Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal, QC, H3A 1A3, Canada.
| | - Jean-Claude Lacaille
- Department of Neurosciences, Center for Interdisciplinary Research On Brain and Learning, Research Group On Neural Signaling and Circuitry, University of Montreal, Montreal, QC, H3T1J4, Canada
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal, QC, H3A 1A3, Canada.
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3
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Bhandare A, Haley M, Torrico Anderson V, Domingos LB, Lopes M, Corrêa SAL, Wall MJ. ArcKR expression modifies synaptic plasticity following epileptic activity: Differential effects with in vitro and in vivo seizure-induction protocols. Epilepsia 2024. [PMID: 38804501 DOI: 10.1111/epi.17981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/25/2024] [Accepted: 03/28/2024] [Indexed: 05/29/2024]
Abstract
OBJECTIVES Pathological forms of neural activity, such as epileptic seizures, modify the expression pattern of multiple proteins, leading to persistent changes in brain function. One such protein is activity-regulated cytoskeleton-associated protein (Arc), which is critically involved in protein-synthesis-dependent synaptic plasticity underlying learning and memory. In the present study, we have investigated how the expression of ArcKR, a form of Arc in which the ubiquitination sites have been mutated, resulting in slowed Arc degradation, modifies group I metabotropic glutamate receptor-mediated long-term depression (G1-mGluR-LTD) following seizures. METHODS We used a knock-in mice line that express ArcKR and two hyperexcitation models: an in vitro model, where hippocampal slices were exposed to zero Mg2+, 6 mM K+; and an in vivo model, where kainic acid was injected unilaterally into the hippocampus. In both models, field excitatory postsynaptic potentials (fEPSPs) were recorded from the CA1 region of hippocampal slices in response to Schaffer collateral stimulation and G1-mGluR-LTD was induced chemically with the group 1 mGluR agonist DHPG. RESULTS In the in vitro model, ArcKR expression enhanced the effects of seizure activity and increased the magnitude of G1-mGluR LTD, an effect that could be blocked with the mGluR5 antagonist MTEP. In the in vivo model, fEPSPs were significantly smaller in slices from ArcKR mice and were less contaminated by population spikes. In this model, the amount of G1-mGluR-LTD was significantly less in epileptic slices from ArcKR mice as compared to wildtype (WT) mice. SIGNIFICANCE We have shown that expression of ArcKR, a form of Arc in which degradation is reduced, significantly modulates the magnitude of G1-mGluR-LTD following epileptic seizures. However, the effect of ArcKR on LTD depends on the epileptic model used, with enhancement of LTD in an in vitro model and a reduction in the kainate mouse model.
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Affiliation(s)
- Amol Bhandare
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Maisy Haley
- School of Life Sciences, University of Warwick, Coventry, UK
| | | | - Luana B Domingos
- Bradford School of Pharmacy and Medical Sciences, University of Bradford, Bradford, UK
| | - Marcia Lopes
- Bradford School of Pharmacy and Medical Sciences, University of Bradford, Bradford, UK
| | - Sonia A L Corrêa
- Bradford School of Pharmacy and Medical Sciences, University of Bradford, Bradford, UK
- Department of Life Sciences, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK
| | - Mark J Wall
- School of Life Sciences, University of Warwick, Coventry, UK
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4
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Yakout DW, Shroff A, Wei W, Thaker V, Allen ZD, Sajish M, Nazarko TY, Mabb AM. Tau regulates Arc stability in neuronal dendrites via a proteasome-sensitive but ubiquitin-independent pathway. J Biol Chem 2024; 300:107237. [PMID: 38552740 PMCID: PMC11061231 DOI: 10.1016/j.jbc.2024.107237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 02/23/2024] [Accepted: 03/19/2024] [Indexed: 04/26/2024] Open
Abstract
Tauopathies are neurodegenerative disorders characterized by the deposition of aggregates of the microtubule-associated protein tau, a main component of neurofibrillary tangles. Alzheimer's disease (AD) is the most common type of tauopathy and dementia, with amyloid-beta pathology as an additional hallmark feature of the disease. Besides its role in stabilizing microtubules, tau is localized at postsynaptic sites and can regulate synaptic plasticity. The activity-regulated cytoskeleton-associated protein (Arc) is an immediate early gene that plays a key role in synaptic plasticity, learning, and memory. Arc has been implicated in AD pathogenesis and regulates the release of amyloid-beta. We found that decreased Arc levels correlate with AD status and disease severity. Importantly, Arc protein was upregulated in the hippocampus of Tau KO mice and dendrites of Tau KO primary hippocampal neurons. Overexpression of tau decreased Arc stability in an activity-dependent manner, exclusively in neuronal dendrites, which was coupled to an increase in the expression of dendritic and somatic surface GluA1-containing α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors. The tau-dependent decrease in Arc was found to be proteasome-sensitive, yet independent of Arc ubiquitination and required the endophilin-binding domain of Arc. Importantly, these effects on Arc stability and GluA1 localization were not observed in the commonly studied tau mutant, P301L. These observations provide a potential molecular basis for synaptic dysfunction mediated through the accumulation of tau in dendrites. Our findings confirm that Arc is misregulated in AD and further show a physiological role for tau in regulating Arc stability and AMPA receptor targeting.
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Affiliation(s)
- Dina W Yakout
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA
| | - Ankit Shroff
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| | - Wei Wei
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA
| | - Vishrut Thaker
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA
| | - Zachary D Allen
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA
| | - Mathew Sajish
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, South Carolina, USA
| | - Taras Y Nazarko
- Department of Biology, Georgia State University, Atlanta, Georgia, USA
| | - Angela M Mabb
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA; Center for Behavioral Neuroscience, Georgia State University, Atlanta, Georgia, USA.
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5
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Wu PY, Ji L, De Sanctis C, Francesconi A, Inglebert Y, McKinney RA. Loss of synaptopodin impairs mGluR5 and protein synthesis-dependent mGluR-LTD at CA3-CA1 synapses. PNAS NEXUS 2024; 3:pgae062. [PMID: 38384385 PMCID: PMC10879843 DOI: 10.1093/pnasnexus/pgae062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 02/01/2024] [Indexed: 02/23/2024]
Abstract
Metabotropic glutamate receptor-dependent long-term depression (mGluR-LTD) is an important form of synaptic plasticity that occurs in many regions of the central nervous system and is the underlying mechanism for several learning paradigms. In the hippocampus, mGluR-LTD is manifested by the weakening of synaptic transmission and elimination of dendritic spines. Interestingly, not all spines respond or undergo plasticity equally in response to mGluR-LTD. A subset of dendritic spines containing synaptopodin (SP), an actin-associated protein is critical for mGluR-LTD and protects spines from elimination through mGluR1 activity. The precise cellular function of SP is still enigmatic and it is still unclear how SP contributes to the functional aspect of mGluR-LTD despite its modulation of the structural plasticity. In this study, we show that the lack of SP impairs mGluR-LTD by negatively affecting the mGluR5-dependent activity. Such impairment of mGluR5 activity is accompanied by a significant decrease of surface mGluR5 level in SP knockout (SPKO) mice. Intriguingly, the remaining mGluR-LTD becomes a protein synthesis-independent process in the SPKO and is mediated instead by endocannabinoid signaling. These data indicate that the postsynaptic protein SP can regulate the locus of expression of mGluR-LTD and provide insight into our understanding of spine/synapse-specific plasticity.
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Affiliation(s)
- Pei You Wu
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Linjia Ji
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Claudia De Sanctis
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Anna Francesconi
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Yanis Inglebert
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
| | - R Anne McKinney
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC H3G 1Y6, Canada
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6
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Barylko B, Taylor CA, Wang J, Earnest S, Stippec S, Binns DD, Brautigam CA, Jameson DM, DeMartino GN, Cobb MH, Albanesi JP. Mimicking Protein Kinase C Phosphorylation Inhibits Arc/Arg3.1 Palmitoylation and Its Interaction with Nucleic Acids. Int J Mol Sci 2024; 25:780. [PMID: 38255853 PMCID: PMC10815921 DOI: 10.3390/ijms25020780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 01/03/2024] [Accepted: 01/04/2024] [Indexed: 01/24/2024] Open
Abstract
Activity-regulated cytoskeleton-associated protein (Arc) plays essential roles in diverse forms of synaptic plasticity, including long-term potentiation (LTP), long-term depression (LTD), and homeostatic plasticity. In addition, it assembles into virus-like particles that may deliver mRNAs and/or other cargo between neurons and neighboring cells. Considering this broad range of activities, it is not surprising that Arc is subject to regulation by multiple types of post-translational modification, including phosphorylation, palmitoylation, SUMOylation, ubiquitylation, and acetylation. Here we explore the potential regulatory role of Arc phosphorylation by protein kinase C (PKC), which occurs on serines 84 and 90 within an α-helical segment in the N-terminal domain. To mimic the effect of PKC phosphorylation, we mutated the two serines to negatively charged glutamic acid. A consequence of introducing these phosphomimetic mutations is the almost complete inhibition of Arc palmitoylation, which occurs on nearby cysteines and contributes to synaptic weakening. The mutations also inhibit the binding of nucleic acids and destabilize high-order Arc oligomers. Thus, PKC phosphorylation of Arc may limit the full expression of LTD and may suppress the interneuronal transport of mRNAs.
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Affiliation(s)
- Barbara Barylko
- Department of Pharmacology, U.T. Southwestern Medical Center, 6001 Forest Park, Dallas, TX 75390, USA; (B.B.); (C.A.T.4th); (D.D.B.); (M.H.C.)
| | - Clinton A. Taylor
- Department of Pharmacology, U.T. Southwestern Medical Center, 6001 Forest Park, Dallas, TX 75390, USA; (B.B.); (C.A.T.4th); (D.D.B.); (M.H.C.)
| | - Jason Wang
- Department of Physiology, U.T. Southwestern Medical Center, 6001 Forest Park, Dallas, TX 75390, USA; (J.W.); (G.N.D.)
| | - Svetlana Earnest
- Department of Pharmacology, U.T. Southwestern Medical Center, 6001 Forest Park, Dallas, TX 75390, USA; (B.B.); (C.A.T.4th); (D.D.B.); (M.H.C.)
| | - Steve Stippec
- Department of Pharmacology, U.T. Southwestern Medical Center, 6001 Forest Park, Dallas, TX 75390, USA; (B.B.); (C.A.T.4th); (D.D.B.); (M.H.C.)
| | - Derk D. Binns
- Department of Pharmacology, U.T. Southwestern Medical Center, 6001 Forest Park, Dallas, TX 75390, USA; (B.B.); (C.A.T.4th); (D.D.B.); (M.H.C.)
| | - Chad A. Brautigam
- Department of Biophysics, U.T. Southwestern Medical Center, 6001 Forest Park, Dallas, TX 75390, USA;
| | - David M. Jameson
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96844, USA;
| | - George N. DeMartino
- Department of Physiology, U.T. Southwestern Medical Center, 6001 Forest Park, Dallas, TX 75390, USA; (J.W.); (G.N.D.)
| | - Melanie H. Cobb
- Department of Pharmacology, U.T. Southwestern Medical Center, 6001 Forest Park, Dallas, TX 75390, USA; (B.B.); (C.A.T.4th); (D.D.B.); (M.H.C.)
| | - Joseph P. Albanesi
- Department of Pharmacology, U.T. Southwestern Medical Center, 6001 Forest Park, Dallas, TX 75390, USA; (B.B.); (C.A.T.4th); (D.D.B.); (M.H.C.)
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7
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Park EH, Kao HY, Jourdi H, van Dijk MT, Carrillo-Segura S, Tunnell KW, Gutierrez J, Wallace EJ, Troy-Regier M, Radwan B, Lesburguères E, Alarcon JM, Fenton AA. Phencyclidine Disrupts Neural Coordination and Cognitive Control by Dysregulating Translation. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2024; 4:252-263. [PMID: 38298788 PMCID: PMC10829677 DOI: 10.1016/j.bpsgos.2023.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 02/02/2024] Open
Abstract
Background Phencyclidine (PCP) causes psychosis, is abused with increasing frequency, and was extensively used in antipsychotic drug discovery. PCP discoordinates hippocampal ensemble action potential discharge and impairs cognitive control in rats, but how this uncompetitive NMDA receptor (NMDAR) antagonist impairs cognition remains unknown. Methods The effects of PCP were investigated on hippocampal CA1 ensemble action potential discharge in vivo in urethane-anesthetized rats and during awake behavior in mice, on synaptic responses in ex vivo mouse hippocampus slices, in mice on a hippocampus-dependent active place avoidance task that requires cognitive control, and on activating the molecular machinery of translation in acute hippocampus slices. Mechanistic causality was assessed by comparing the PCP effects with the effects of inhibitors of protein synthesis, group I metabotropic glutamate receptors (mGluR1/5), and subunit-selective NMDARs. Results Consistent with ionotropic actions, PCP discoordinated CA1 ensemble action potential discharge. PCP caused hyperactivity and impaired active place avoidance, despite the rodents having learned the task before PCP administration. Consistent with metabotropic actions, PCP exaggerated protein synthesis-dependent DHPG-induced mGluR1/5-stimulated long-term synaptic depression. Pretreatment with anisomycin or the mGluR1/5 antagonist MPEP, both of which repress translation, prevented PCP-induced discoordination and the cognitive and sensorimotor impairments. PCP as well as the NR2A-containing NMDAR antagonist NVP-AAM077 unbalanced translation that engages the Akt, mTOR (mechanistic target of rapamycin), and 4EBP1 translation machinery and increased protein synthesis, whereas the NR2B-containing antagonist Ro25-6981 did not. Conclusions PCP dysregulates translation, acting through NR2A-containing NMDAR subtypes, recruiting mGluR1/5 signaling pathways, and leading to neural discoordination that is central to the cognitive and sensorimotor impairments.
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Affiliation(s)
- Eun Hye Park
- Center for Neural Science, New York University, New York, New York
| | - Hsin-Yi Kao
- Center for Neural Science, New York University, New York, New York
| | - Hussam Jourdi
- Center for Neural Science, New York University, New York, New York
| | - Milenna T. van Dijk
- Center for Neural Science, New York University, New York, New York
- Graduate Program in Neuroscience and Physiology, New York University Langone Medical Center, New York, New York
| | - Simón Carrillo-Segura
- Center for Neural Science, New York University, New York, New York
- Graduate Program in Mechanical and Aerospace Engineering, New York University Tandon School of Engineering, New York, New York
| | - Kayla W. Tunnell
- Center for Neural Science, New York University, New York, New York
| | | | - Emma J. Wallace
- Graduate Program in Neural and Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, New York
- Department of Physiology and Pharmacology, State University of New York, Downstate Health Sciences University, Brooklyn, New York
| | - Matthew Troy-Regier
- Graduate Program in Neural and Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, New York
- Department of Physiology and Pharmacology, State University of New York, Downstate Health Sciences University, Brooklyn, New York
| | - Basma Radwan
- Graduate Program in Neural Science, Center for Neural Science, New York University, New York, New York
| | | | - Juan Marcos Alarcon
- Department of Pathology, State University of New York, Downstate Health Sciences University, Brooklyn, New York
- Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, New York
| | - André A. Fenton
- Center for Neural Science, New York University, New York, New York
- Department of Physiology and Pharmacology, State University of New York, Downstate Health Sciences University, Brooklyn, New York
- Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, New York
- Neuroscience Institute, NYU Langone Health, New York, New York
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8
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Wu X, Liu L, Xue X, Li X, Zhao K, Zhang J, Li W, Yao W, Ding S, Jia C, Zhu F. Captive ERVWE1 triggers impairment of 5-HT neuronal plasticity in the first-episode schizophrenia by post-transcriptional activation of HTR1B in ALKBH5-m6A dependent epigenetic mechanisms. Cell Biosci 2023; 13:213. [PMID: 37990254 PMCID: PMC10664518 DOI: 10.1186/s13578-023-01167-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 11/07/2023] [Indexed: 11/23/2023] Open
Abstract
BACKGROUND Abnormalities in the 5-HT system and synaptic plasticity are hallmark features of schizophrenia. Previous studies suggest that the human endogenous retrovirus W family envelope (ERVWE1) is an influential risk factor for schizophrenia and inversely correlates with 5-HT4 receptor in schizophrenia. To our knowledge, no data describes the effect of ERVWE1 on 5-HT neuronal plasticity. N6-methyladenosine (m6A) regulates gene expression and impacts synaptic plasticity. Our research aims to systematically investigate the effects of ERVWE1 on 5-HT neuronal plasticity through m6A modification in schizophrenia. RESULTS HTR1B, ALKBH5, and Arc exhibited higher levels in individuals with first-episode schizophrenia compared to the controls and showed a strong positive correlation with ERVWE1. Interestingly, HTR1B was also correlated with ALKBH5 and Arc. Further analyses confirmed that ALKBH5 may be an independent risk factor for schizophrenia. In vitro studies, we discovered that ERVWE1 enhanced HTR1B expression, thereby activating the ERK-ELK1-Arc pathway and reducing the complexity and spine density of 5-HT neurons. Furthermore, ERVWE1 reduced m6A levels through ALKBH5 demethylation. ERVWE1 induced HTR1B upregulation by improving its mRNA stability in ALKBH5-m6A-dependent epigenetic mechanisms. Importantly, ALKBH5 mediated the observed alterations in 5-HT neuronal plasticity induced by ERVWE1. CONCLUSIONS Overall, HTR1B, Arc, and ALKBH5 levels were increased in schizophrenia and positively associated with ERVWE1. Moreover, ALKBH5 was a novel risk gene for schizophrenia. ERVWE1 impaired 5-HT neuronal plasticity in ALKBH5-m6A dependent mechanism by the HTR1B-ERK-ELK1-Arc pathway, which may be an important contributor to aberrant synaptic plasticity in schizophrenia.
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Affiliation(s)
- Xiulin Wu
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, China
| | | | - Xing Xue
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, China
| | - Xuhang Li
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, China
| | - Kexin Zhao
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, China
| | - Jiahang Zhang
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, China
| | - Wenshi Li
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, China
| | - Wei Yao
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, China
| | - Shuang Ding
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, China
| | - Chen Jia
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, China
| | - Fan Zhu
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, China.
- Hubei Province Key Laboratory of Allergy & Immunology, Wuhan University, Wuhan, 430071, China.
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9
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Haley M, Bertrand J, Anderson VT, Fuad M, Frenguelli BG, Corrêa SAL, Wall MJ. Arc expression regulates long-term potentiation magnitude and metaplasticity in area CA1 of the hippocampus in ArcKR mice. Eur J Neurosci 2023; 58:4166-4180. [PMID: 37821126 DOI: 10.1111/ejn.16172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 09/18/2023] [Accepted: 09/26/2023] [Indexed: 10/13/2023]
Abstract
Expression of the immediate early gene Arc/Arg3.1 (Arc), a key mediator of synaptic plasticity, is enhanced by neural activity and then reduced by proteasome-dependent degradation. We have previously shown that the disruption of Arc degradation, in an Arc knock-in mouse (ArcKR), where the predominant Arc ubiquitination sites were mutated, reduced the threshold to induce, and also enhanced, the strength of Group I metabotropic glutamate receptor-mediated long-term depression (DHPG-LTD). Here, we have investigated if ArcKR expression changes long-term potentiation (LTP) in CA1 area of the hippocampus. As previously reported, there was no change in basal synaptic transmission at Schaffer collateral/commissural-CA1 (SC-CA1) synapses in ArcKR versus wild-type (WT) mice. There was, however, a significant increase in the amplitude of synaptically induced (with low frequency paired-pulse stimulation) LTD in ArcKR mice. Theta burst stimulation (TBS)-evoked LTP at SC-CA1 synapses was significantly reduced in ArcKR versus WT mice (after 2 h). Group 1 mGluR priming of LTP was abolished in ArcKR mice, which could also potentially contribute to a depression of LTP. Although high frequency stimulation (HFS)-induced LTP was not significantly different in ArcKR compared with WT mice (after 1 h), there was a phenotype in environmentally enriched mice, with the ratio of LTP to short-term potentiation (STP) significantly reduced in ArcKR mice. These findings support the hypothesis that Arc ubiquitination supports the induction and expression of LTP, likely via limiting Arc-dependent removal of AMPA receptors at synapses.
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Affiliation(s)
- Maisy Haley
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Jeanri Bertrand
- School of Life Sciences, University of Warwick, Coventry, UK
| | | | - Mukattar Fuad
- School of Life Sciences, University of Warwick, Coventry, UK
| | | | - Sonia A L Corrêa
- Faculty of Science and Engineering, Department of Life Sciences, John Dalton Building, Room E210, Manchester Metropolitan University, Manchester, UK
| | - Mark J Wall
- School of Life Sciences, University of Warwick, Coventry, UK
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10
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Barry SM, Barry GM, Martinez D, Penrod RD, Cowan CW. The activity-regulated cytoskeleton-associated protein, Arc, functions in the nucleus accumbens shell to limit multiple triggers of cocaine-seeking behaviour. Addict Biol 2023; 28:e13335. [PMID: 37753560 DOI: 10.1111/adb.13335] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 08/01/2023] [Accepted: 08/28/2023] [Indexed: 09/28/2023]
Abstract
Use of addictive substances like cocaine produces enduring associations between the drug experience and cues in the drug-taking environment. In individuals with a substance use disorder (SUD) and attempting to remain abstinent, these powerful drug-cue associations can trigger a return to active drug use, but the molecular mechanisms regulating drug-cue associations remain poorly understood. The activity-regulated cytoskeleton-associated protein (Arc) is induced by cocaine in the nucleus accumbens (NAc), an important brain reward region, but Arc's NAc function in SUD-related behaviour remains unclear. We show here that cocaine self-administration (SA) in rats produced a significant upregulation of Arc protein in both the core and shell subregions of the NAc. Subregion-specific Arc reduction (shRNA) in the medial NAc Shell enhanced both context-associated and cue-reinstated cocaine seeking, but without altering the motivation to work for cocaine, the sensitivity to the reinforcing effects of cocaine or the ability of cocaine priming to reinstate drug seeking. In contrast, we observed no effects of Arc knockdown in the NAc core on any aspect of cocaine SA, extinction or reinstated cocaine seeking, suggesting that Arc functions within the medial NAc shell, but not NAc core, to limit the strength of drug-context and drug-cue associations that promote cocaine-seeking behaviour.
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Affiliation(s)
- Sarah M Barry
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Gabriella M Barry
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Dalia Martinez
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Rachel D Penrod
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Christopher W Cowan
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, USA
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11
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Bijoch Ł, Klos J, Pękała M, Fiołna K, Kaczmarek L, Beroun A. Diverse processing of pharmacological and natural rewards by the central amygdala. Cell Rep 2023; 42:113036. [PMID: 37616162 DOI: 10.1016/j.celrep.2023.113036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 07/03/2023] [Accepted: 08/11/2023] [Indexed: 08/25/2023] Open
Abstract
The central amygdala (CeA) with its medial (CeM) and lateral (CeL) nuclei is the brain hub for processing stimuli with emotional context. CeL nucleus gives a strong inhibitory input to the CeM, and this local circuitry assigns values (positive or negative) to incoming stimuli, guiding appropriate behavior (approach or avoid). However, the particular involvement of CeA in processing such emotionally relevant information and adaptations of the CeA circuitry are not yet well understood. In this study, we examined synaptic plasticity in the CeA after exposure to two types of rewards, pharmacological (cocaine) and natural (sugar). We found that both rewards engage CeM, where they generate silent synapses resulting in the strengthening of the network. However, only cocaine triggers plasticity in the CeL, which leads to the weakening of its excitatory inputs. Finally, chemogenetic inhibition of CeM attenuates animal preference for sugar, while activation delays cocaine-induced increase in locomotor activity.
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Affiliation(s)
- Łukasz Bijoch
- Nencki-EMBL Center of Excellence for Neural Plasticity and Brain Disorders: BRAINCITY, Laboratory of Neuronal Plasticity, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, L. Pasteura 3, 02-093 Warsaw, Poland
| | - Joanna Klos
- Nencki-EMBL Center of Excellence for Neural Plasticity and Brain Disorders: BRAINCITY, Laboratory of Neuronal Plasticity, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, L. Pasteura 3, 02-093 Warsaw, Poland
| | - Martyna Pękała
- Nencki-EMBL Center of Excellence for Neural Plasticity and Brain Disorders: BRAINCITY, Laboratory of Neurobiology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, L. Pasteura 3, 02-093 Warsaw, Poland
| | - Kristina Fiołna
- Nencki-EMBL Center of Excellence for Neural Plasticity and Brain Disorders: BRAINCITY, Laboratory of Neuronal Plasticity, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, L. Pasteura 3, 02-093 Warsaw, Poland; Nencki-EMBL Center of Excellence for Neural Plasticity and Brain Disorders: BRAINCITY, Laboratory of Neurobiology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, L. Pasteura 3, 02-093 Warsaw, Poland
| | - Leszek Kaczmarek
- Nencki-EMBL Center of Excellence for Neural Plasticity and Brain Disorders: BRAINCITY, Laboratory of Neurobiology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, L. Pasteura 3, 02-093 Warsaw, Poland
| | - Anna Beroun
- Nencki-EMBL Center of Excellence for Neural Plasticity and Brain Disorders: BRAINCITY, Laboratory of Neuronal Plasticity, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, L. Pasteura 3, 02-093 Warsaw, Poland.
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12
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Wu PY, Ji L, De Sanctis C, Francesconi A, Inglebert Y, McKinney RA. Loss of synaptopodin impairs mGluR5 and protein synthesis dependent mGluR-LTD at CA3-CA1 synapses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.02.551676. [PMID: 37577654 PMCID: PMC10418280 DOI: 10.1101/2023.08.02.551676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Metabotropic glutamate receptor-dependent long-term depression (mGluR-LTD) is an important form of synaptic plasticity that occurs in many regions of the CNS and is the underlying mechanism for several learning paradigms. In the hippocampus, mGluR-LTD is manifested by the weakening of synaptic transmission and elimination of dendritic spines. Interestingly, not all spines respond or undergo plasticity equally in response to mGluR-LTD. A subset of dendritic spines containing synaptopodin (SP), an actin-associated protein, are critical for mGluR-LTD and protect spines from elimination through mGluR1 activity. The precise cellular function of SP is still enigmatic and it is still unclear how SP contributes to the functional aspect of mGluR-LTD despite of its modulation on the structural plasticity. In the present study, we show that the lack of SP impairs mGluR-LTD by negatively affecting the mGluR5-dependent activity. Such impairment of mGluR5 activity is accompanied by a significant decrease of surface mGluR5 level in SP knockout (SPKO) mice. Intriguingly, the remaining mGluR-LTD becomes a protein synthesis-independent process in the SPKO and is mediated instead by endocannabinoid signaling. These data show for the first time that the postsynaptic protein SP can regulate the locus of expression of mGluR-LTD and provide insight to our understanding of spine/synapse-specific plasticity. Significance statement Hippocampal group I metabotropic glutamate receptor dependent long-term depression (mGluR-LTD), a form of learning and memory, is misregulated in many murine models of neurodevelopmental disorders. Despite extensive studies there is a paucity of information on the molecular mechanism underlying mGluR-LTD. Previously, we reported that loss of synaptopodin, an actin-associated protein found in a subset of mature dendritic spines, impairs mGluR-LTD. In the current study, we uncover the molecular and cellular deficits involved. We find that synaptopodin is required for the mGluR5-Homer interaction and uncover synaptopodin as a molecular switch for mGluR-LTD expression, as mGluR-LTD becomes protein synthesis-independent and relies on endocannabinoid signaling in synaptopodin knock-out. This work provides insight into synaptopodin as a gatekeeper to regulate mGluR-LTD at hippocampal synapses.
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13
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Jong YJI, Izumi Y, Harmon SK, Zorumski CF, ÓMalley KL. Striatal mGlu 5-mediated synaptic plasticity is independently regulated by location-specific receptor pools and divergent signaling pathways. J Biol Chem 2023; 299:104949. [PMID: 37354970 PMCID: PMC10388212 DOI: 10.1016/j.jbc.2023.104949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 06/26/2023] Open
Abstract
Metabotropic glutamate receptor 5 (mGlu5) is widely expressed throughout the central nervous system and is involved in neuronal function, synaptic transmission, and a number of neuropsychiatric disorders such as depression, anxiety, and autism. Recent work from this lab showed that mGlu5 is one of a growing number of G protein-coupled receptors that can signal from intracellular membranes where it drives unique signaling pathways, including upregulation of extracellular signal-regulated kinase (ERK1/2), ETS transcription factor Elk-1, and activity-regulated cytoskeleton-associated protein (Arc). To determine the roles of cell surface mGlu5 as well as the intracellular receptor in a well-known mGlu5 synaptic plasticity model such as long-term depression, we used pharmacological isolation and genetic and physiological approaches to analyze spatially restricted pools of mGlu5 in striatal cultures and slice preparations. Here we show that both intracellular and cell surface receptors activate the phosphatidylinositol-3-kinase-protein kinase B-mammalian target of rapamycin (PI3K/AKT/mTOR) pathway, whereas only intracellular mGlu5 activates protein phosphatase 2 and leads to fragile X mental retardation protein degradation and de novo protein synthesis followed by a protein synthesis-dependent increase in Arc and post-synaptic density protein 95. However, both cell surface and intracellular mGlu5 activation lead to α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor GluA2 internalization and chemically induced long-term depression albeit via different signaling mechanisms. These data underscore the importance of intracellular mGlu5 in the cascade of events associated with sustained synaptic transmission in the striatum.
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Affiliation(s)
- Yuh-Jiin I Jong
- Department of Neuroscience, Washington University School of Medicine, St Louis, Missouri, USA
| | - Yukitoshi Izumi
- Department of Psychiatry, Washington University School of Medicine, St Louis, Missouri, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St Louis, Missouri, USA
| | - Steven K Harmon
- Department of Neuroscience, Washington University School of Medicine, St Louis, Missouri, USA
| | - Charles F Zorumski
- Department of Neuroscience, Washington University School of Medicine, St Louis, Missouri, USA; Department of Psychiatry, Washington University School of Medicine, St Louis, Missouri, USA; The Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St Louis, Missouri, USA
| | - Karen L ÓMalley
- Department of Neuroscience, Washington University School of Medicine, St Louis, Missouri, USA.
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14
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Escobar I, Xu J, Jackson CW, Stegelmann SD, Fagerli EA, Dave KR, Perez-Pinzon MA. Resveratrol Preconditioning Protects Against Ischemia-Induced Synaptic Dysfunction and Cofilin Hyperactivation in the Mouse Hippocampal Slice. Neurotherapeutics 2023; 20:1177-1197. [PMID: 37208551 PMCID: PMC10457274 DOI: 10.1007/s13311-023-01386-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2023] [Indexed: 05/21/2023] Open
Abstract
Perturbations in synaptic function are major determinants of several neurological diseases and have been associated with cognitive impairments after cerebral ischemia (CI). Although the mechanisms underlying CI-induced synaptic dysfunction have not been well defined, evidence suggests that early hyperactivation of the actin-binding protein, cofilin, plays a role. Given that synaptic impairments manifest shortly after CI, prophylactic strategies may offer a better approach to prevent/mitigate synaptic damage following an ischemic event. Our laboratory has previously demonstrated that resveratrol preconditioning (RPC) promotes cerebral ischemic tolerance, with many groups highlighting beneficial effects of resveratrol treatment on synaptic and cognitive function in other neurological conditions. Herein, we hypothesized that RPC would mitigate hippocampal synaptic dysfunction and pathological cofilin hyperactivation in an ex vivo model of ischemia. Various electrophysiological parameters and synaptic-related protein expression changes were measured under normal and ischemic conditions utilizing acute hippocampal slices derived from adult male mice treated with resveratrol (10 mg/kg) or vehicle 48 h prior. Remarkably, RPC significantly increased the latency to anoxic depolarization, decreased cytosolic calcium accumulation, prevented aberrant increases in synaptic transmission, and rescued deficits in long-term potentiation following ischemia. Additionally, RPC upregulated the expression of the activity-regulated cytoskeleton associated protein, Arc, which was partially required for RPC-mediated attenuation of cofilin hyperactivation. Taken together, these findings support a role for RPC in mitigating CI-induced excitotoxicity, synaptic dysfunction, and pathological over-activation of cofilin. Our study provides further insight into mechanisms underlying RPC-mediated neuroprotection against CI and implicates RPC as a promising strategy to preserve synaptic function after ischemia.
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Affiliation(s)
- Iris Escobar
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Department of Neurology, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
| | - Jing Xu
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Department of Neurology, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
| | - Charles W Jackson
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Department of Neurology, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
| | - Samuel D Stegelmann
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Department of Neurology, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
| | - Eric A Fagerli
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Department of Neurology, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
| | - Kunjan R Dave
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Department of Neurology, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
- Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA
| | - Miguel A Perez-Pinzon
- Peritz Scheinberg Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA.
- Department of Neurology, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA.
- Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, PO Box 016960, Miami, FL, 33101, USA.
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15
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Wilkerson JR, Ifrim MF, Valdez-Sinon AN, Hahn P, Bowles JE, Molinaro G, Janusz-Kaminska A, Bassell GJ, Huber KM. FMRP phosphorylation and interactions with Cdh1 regulate association with dendritic RNA granules and MEF2-triggered synapse elimination. Neurobiol Dis 2023; 182:106136. [PMID: 37120096 PMCID: PMC10370323 DOI: 10.1016/j.nbd.2023.106136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/12/2023] [Accepted: 04/24/2023] [Indexed: 05/01/2023] Open
Abstract
Fragile X Messenger Ribonucleoprotein (FMRP) is necessary for experience-dependent, developmental synapse elimination and the loss of this process may underlie the excess dendritic spines and hyperconnectivity of cortical neurons in Fragile X Syndrome, a common inherited form of intellectual disability and autism. Little is known of the signaling pathways that regulate synapse elimination and if or how FMRP is regulated during this process. We have characterized a model of synapse elimination in CA1 neurons of organotypic hippocampal slice cultures that is induced by expression of the active transcription factor Myocyte Enhancer Factor 2 (MEF2) and relies on postsynaptic FMRP. MEF2-induced synapse elimination is deficient in Fmr1 KO CA1 neurons, and is rescued by acute (24 h), postsynaptic and cell autonomous reexpression of FMRP in CA1 neurons. FMRP is an RNA binding protein that suppresses mRNA translation. Derepression is induced by posttranslational mechanisms downstream of metabotropic glutamate receptor signaling. Dephosphorylation of FMRP at S499 triggers ubiquitination and degradation of FMRP which then relieves translation suppression and promotes synthesis of proteins encoded by target mRNAs. Whether this mechanism functions in synapse elimination is not known. Here we demonstrate that phosphorylation and dephosphorylation of FMRP at S499 are both necessary for synapse elimination as well as interaction of FMRP with its E3 ligase for FMRP, APC/Cdh1. Using a bimolecular ubiquitin-mediated fluorescence complementation (UbFC) assay, we demonstrate that MEF2 promotes ubiquitination of FMRP in CA1 neurons that relies on activity and interaction with APC/Cdh1. Our results suggest a model where MEF2 regulates posttranslational modifications of FMRP via APC/Cdh1 to regulate translation of proteins necessary for synapse elimination.
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Affiliation(s)
- Julia R Wilkerson
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Marius F Ifrim
- Department of Cell and Developmental Biology, State University of New York, Upstate Medical University, Syracuse, NY 13210, USA; Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | - Patricia Hahn
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jacob E Bowles
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Gemma Molinaro
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | | | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Kimberly M Huber
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA.
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16
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Mergiya TF, Gundersen JET, Kanhema T, Brighter G, Ishizuka Y, Bramham CR. Detection of Arc/Arg3.1 oligomers in rat brain: constitutive and synaptic activity-evoked dimer expression in vivo. Front Mol Neurosci 2023; 16:1142361. [PMID: 37363319 PMCID: PMC10289200 DOI: 10.3389/fnmol.2023.1142361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 05/12/2023] [Indexed: 06/28/2023] Open
Abstract
The immediate early gene product activity-regulated cytoskeleton-associated protein (Arc or Arg3.1) is a major regulator of long-term synaptic plasticity with critical roles in postnatal cortical development and memory formation. However, the molecular basis of Arc function is undefined. Arc is a hub protein with interaction partners in the postsynaptic neuronal compartment and nucleus. Previous in vitro biochemical and biophysical analysis of purified recombinant Arc showed formation of low-order oligomers and larger particles including retrovirus-like capsids. Here, we provide evidence for naturally occurring Arc oligomers in the mammalian brain. Using in situ protein crosslinking to trap weak Arc-Arc interactions, we identified in various preparations a prominent Arc immunoreactive band on SDS-PAGE of molecular mass corresponding to a dimer. While putative trimers, tetramers and heavier Arc species were detected, they were of lower abundance. Stimulus-evoked induction of Arc expression and dimer formation was first demonstrated in SH-SY5Y neuroblastoma cells treated with the muscarinic cholinergic agonist, carbachol, and in primary cortical neuronal cultures treated with brain-derived neurotrophic factor (BDNF). In the dentate gyrus (DG) of adult anesthetized rats, induction of long-term potentiation (LTP) by high-frequency stimulation (HFS) of medial perforant synapses or by brief intrahippocampal infusion of BDNF led to a massive increase in Arc dimer expression. Arc immunoprecipitation of crosslinked DG tissue showed enhanced dimer expression during 4 h of LTP maintenance. Mass spectrometric proteomic analysis of immunoprecipitated, gel-excised bands corroborated detection of Arc dimer. Furthermore, Arc dimer was constitutively expressed in naïve cortical, hippocampal and DG tissue, with the lowest levels in the DG. Taken together the results implicate Arc dimer as the predominant low-oligomeric form in mammalian brain, exhibiting regional differences in its constitutive expression and enhanced synaptic activity-evoked expression in LTP.
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Affiliation(s)
- Tadiwos F. Mergiya
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Mohn Research Center for the Brain, University of Bergen, Bergen, Norway
| | - Jens Edvard Trygstad Gundersen
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Mohn Research Center for the Brain, University of Bergen, Bergen, Norway
| | - Tambudzai Kanhema
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Mohn Research Center for the Brain, University of Bergen, Bergen, Norway
| | - Grant Brighter
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Yuta Ishizuka
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Clive R. Bramham
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Mohn Research Center for the Brain, University of Bergen, Bergen, Norway
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17
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Schulz L, Ramirez P, Lemieux A, Gonzalez E, Thomson T, Frost B. Tau-Induced Elevation of the Activity-Regulated Cytoskeleton Associated Protein Arc1 Causally Mediates Neurodegeneration in the Adult Drosophila Brain. Neuroscience 2023; 518:101-111. [PMID: 35487302 PMCID: PMC9606145 DOI: 10.1016/j.neuroscience.2022.04.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/18/2022] [Accepted: 04/21/2022] [Indexed: 11/24/2022]
Abstract
Alzheimer's disease and other tauopathies are neurodegenerative disorders pathologically defined by aggregated forms of tau protein in the brain. While synaptic degradation is a well-established feature of tau-induced neurotoxicity, the underlying mechanisms of how pathogenic forms of tau drive synaptic dysfunction are incompletely understood. Synaptic function and subsequent memory consolidation are dependent upon synaptic plasticity, the ability of synapses to adjust their structure and strength in response to changes in activity. The activity regulated cytoskeleton associated protein ARC acts in the nucleus and at postsynaptic densities to regulate various forms of synaptic plasticity. ARC harbors a retrovirus-like Gag domain that facilitates ARC multimerization and capsid formation. Trans-synaptic transfer of RNA-containing ARC capsids is required for synaptic plasticity. While ARC is elevated in brains of patients with Alzheimer's disease and genetic variants in ARC increase susceptibility to Alzheimer's disease, mechanistic insight into the role of ARC in Alzheimer's disease is lacking. Using a Drosophila model of tauopathy, we find that pathogenic tau significantly increases multimeric species of the protein encoded by the Drosophila homolog of ARC, Arc1, in the adult fly brain. We find that Arc1 is elevated within nuclei and the neuropil of tau transgenic Drosophila, but does not localize to synaptic vesicles or presynaptic terminals. Lastly, we find that genetic manipulation of Arc1 modifies tau-induced neurotoxicity, suggesting that tau-induced Arc1 elevation mediates neurodegeneration. Taken together, our results suggest that ARC elevation in human Alzheimer's disease is a consequence of tau pathology and is a causal factor contributing to neuronal death.
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Affiliation(s)
- Lulu Schulz
- Barshop Institute for Longevity and Aging Studies, San Antonio, TX, United States; Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, San Antonio, TX, United States; Department of Cell Systems and Anatomy, San Antonio, TX, United States; University of Texas Health San Antonio, San Antonio, TX, United States
| | - Paulino Ramirez
- Barshop Institute for Longevity and Aging Studies, San Antonio, TX, United States; Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, San Antonio, TX, United States; Department of Cell Systems and Anatomy, San Antonio, TX, United States; University of Texas Health San Antonio, San Antonio, TX, United States
| | - Adrienne Lemieux
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA, United States
| | - Elias Gonzalez
- Barshop Institute for Longevity and Aging Studies, San Antonio, TX, United States; Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, San Antonio, TX, United States; Department of Cell Systems and Anatomy, San Antonio, TX, United States; University of Texas Health San Antonio, San Antonio, TX, United States
| | - Travis Thomson
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA, United States
| | - Bess Frost
- Barshop Institute for Longevity and Aging Studies, San Antonio, TX, United States; Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, San Antonio, TX, United States; Department of Cell Systems and Anatomy, San Antonio, TX, United States; University of Texas Health San Antonio, San Antonio, TX, United States.
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18
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Wagle S, Kraynyukova N, Hafner AS, Tchumatchenko T. Computational insights into mRNA and protein dynamics underlying synaptic plasticity rules. Mol Cell Neurosci 2023; 125:103846. [PMID: 36963534 DOI: 10.1016/j.mcn.2023.103846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 03/26/2023] Open
Abstract
Recent advances in experimental techniques provide an unprecedented peek into the intricate molecular dynamics inside synapses and dendrites. The experimental insights into the molecular turnover revealed that such processes as diffusion, active transport, spine uptake, and local protein synthesis could dynamically modulate the copy numbers of plasticity-related molecules in synapses. Subsequently, theoretical models were designed to understand the interaction of these processes better and to explain how local synaptic plasticity cues can up or down-regulate the molecular copy numbers across synapses. In this review, we discuss the recent advances in experimental techniques and computational models to highlight how these complementary approaches can provide insight into molecular cross-talk across synapses, ultimately allowing us to develop biologically-inspired neural network models to understand brain function.
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Affiliation(s)
- Surbhit Wagle
- Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Anselm-Franz-von-Bentzel-Weg 3, 55128 Mainz, Germany
| | - Nataliya Kraynyukova
- Institute of Experimental Epileptology and Cognition Research, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Anne-Sophie Hafner
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands; Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - Tatjana Tchumatchenko
- Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Anselm-Franz-von-Bentzel-Weg 3, 55128 Mainz, Germany; Institute of Experimental Epileptology and Cognition Research, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany.
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19
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Dysregulation of AMPA Receptor Trafficking and Intracellular Vesicular Sorting in the Prefrontal Cortex of Dopamine Transporter Knock-Out Rats. Biomolecules 2023; 13:biom13030516. [PMID: 36979451 PMCID: PMC10046215 DOI: 10.3390/biom13030516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/23/2023] [Accepted: 03/08/2023] [Indexed: 03/18/2023] Open
Abstract
Dopamine (DA) and glutamate interact, influencing neural excitability and promoting synaptic plasticity. However, little is known regarding the molecular mechanisms underlying this crosstalk. Since perturbation of DA-AMPA receptor interaction might sustain pathological conditions, the major aim of our work was to evaluate the effect of the hyperactive DA system on the AMPA subunit composition, trafficking, and membrane localization in the prefrontal cortex (PFC). Taking advantage of dopamine transporter knock-out (DAT−/−) rats, we found that DA overactivity reduced the translation of cortical AMPA receptors and their localization at both synaptic and extra-synaptic sites through, at least in part, altered intracellular vesicular sorting. Moreover, the reduced expression of AMPA receptor-specific anchoring proteins and structural markers, such as Neuroligin-1 and nCadherin, likely indicate a pattern of synaptic instability. Overall, these data reveal that a condition of hyperdopaminergia markedly alters the homeostatic plasticity of AMPA receptors, suggesting a general destabilization and depotentiation of the AMPA-mediated glutamatergic neurotransmission in the PFC. This effect might be functionally relevant for disorders characterized by elevated dopaminergic activity.
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20
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Velazquez-Sanchez C, Muresan L, Marti-Prats L, Belin D. The development of compulsive coping behaviour is associated with a downregulation of Arc in a Locus Coeruleus neuronal ensemble. Neuropsychopharmacology 2023; 48:653-663. [PMID: 36635597 PMCID: PMC9938202 DOI: 10.1038/s41386-022-01522-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 01/14/2023]
Abstract
Some compulsive disorders have been considered to stem from the loss of control over coping strategies, such as displacement. However, the cellular mechanisms involved in the acquisition of coping behaviours and their subsequent compulsive manifestation in vulnerable individuals have not been elucidated. Considering the role of the locus coeruleus (LC) noradrenaline-dependent system in stress and related excessive behaviours, we hypothesised that neuroplastic changes in the LC may be associated with the acquisition of an adjunctive polydipsic water drinking, a prototypical displacement behaviour, and the ensuing development of compulsion in vulnerable individuals. Thus, male Sprague Dawley rats were characterised for their tendency, or not, to develop compulsive polydipsic drinking in a schedule-induced polydipsia (SIP) procedure before their fresh brains were harvested. A new quantification tool for RNAscope assays revealed that the development of compulsive adjunctive behaviour was associated with a low mRNA copy number of the plasticity marker Arc in the LC which appeared to be driven by specific adaptations in an ensemble of tyrosine hydroxylase (TH)+, zif268- neurons. This ensemble was specifically engaged by the expression of compulsive adjunctive behaviour, not by stress, because its functional recruitment was not observed in individuals that no longer had access to the water bottle before sacrifice, while it consistently correlated with the levels of polydipsic water drinking only when it had become compulsive. Together these findings suggest that downregulation of Arc mRNA levels in a population of a TH+/zif268- LC neurons represents a signature of the tendency to develop compulsive coping behaviours.
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Affiliation(s)
- Clara Velazquez-Sanchez
- CLIC (Cambridge Laboratory for research on Impulsive/Compulsive disorders), Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK
| | - Leila Muresan
- Cambridge Advanced Imaging Centre, Department of Physiology Development and Neuroscience of the University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK
| | - Lucia Marti-Prats
- CLIC (Cambridge Laboratory for research on Impulsive/Compulsive disorders), Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK
| | - David Belin
- CLIC (Cambridge Laboratory for research on Impulsive/Compulsive disorders), Department of Psychology, University of Cambridge, Downing Street, Cambridge, CB2 3EB, UK.
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21
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Dysregulated Signaling at Postsynaptic Density: A Systematic Review and Translational Appraisal for the Pathophysiology, Clinics, and Antipsychotics' Treatment of Schizophrenia. Cells 2023; 12:cells12040574. [PMID: 36831241 PMCID: PMC9954794 DOI: 10.3390/cells12040574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 02/12/2023] Open
Abstract
Emerging evidence from genomics, post-mortem, and preclinical studies point to a potential dysregulation of molecular signaling at postsynaptic density (PSD) in schizophrenia pathophysiology. The PSD that identifies the archetypal asymmetric synapse is a structure of approximately 300 nm in diameter, localized behind the neuronal membrane in the glutamatergic synapse, and constituted by more than 1000 proteins, including receptors, adaptors, kinases, and scaffold proteins. Furthermore, using FASS (fluorescence-activated synaptosome sorting) techniques, glutamatergic synaptosomes were isolated at around 70 nm, where the receptors anchored to the PSD proteins can diffuse laterally along the PSD and were stabilized by scaffold proteins in nanodomains of 50-80 nm at a distance of 20-40 nm creating "nanocolumns" within the synaptic button. In this context, PSD was envisioned as a multimodal hub integrating multiple signaling-related intracellular functions. Dysfunctions of glutamate signaling have been postulated in schizophrenia, starting from the glutamate receptor's interaction with scaffolding proteins involved in the N-methyl-D-aspartate receptor (NMDAR). Despite the emerging role of PSD proteins in behavioral disorders, there is currently no systematic review that integrates preclinical and clinical findings addressing dysregulated PSD signaling and translational implications for antipsychotic treatment in the aberrant postsynaptic function context. Here we reviewed a critical appraisal of the role of dysregulated PSD proteins signaling in the pathophysiology of schizophrenia, discussing how antipsychotics may affect PSD structures and synaptic plasticity in brain regions relevant to psychosis.
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22
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Calis D, Hess M, Marchetta P, Singer W, Modro J, Nelissen E, Prickaerts J, Sandner P, Lukowski R, Ruth P, Knipper M, Rüttiger L. Acute deletion of the central MR/GR steroid receptor correlates with changes in LTP, auditory neural gain, and GC-A cGMP signaling. Front Mol Neurosci 2023; 16:1017761. [PMID: 36873102 PMCID: PMC9983609 DOI: 10.3389/fnmol.2023.1017761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 01/18/2023] [Indexed: 02/19/2023] Open
Abstract
The complex mechanism by which stress can affect sensory processes such as hearing is still poorly understood. In a previous study, the mineralocorticoid (MR) and/or glucocorticoid receptor (GR) were deleted in frontal brain regions but not cochlear regions using a CaMKIIα-based tamoxifen-inducible Cre ERT2/loxP approach. These mice exhibit either a diminished (MRTMXcKO) or disinhibited (GRTMXcKO) auditory nerve activity. In the present study, we observed that mice differentially were (MRTMXcKO) or were not (GRTMXcKO) able to compensate for altered auditory nerve activity in the central auditory pathway. As previous findings demonstrated a link between central auditory compensation and memory-dependent adaptation processes, we analyzed hippocampal paired-pulse facilitation (PPF) and long-term potentiation (LTP). To determine which molecular mechanisms may impact differences in synaptic plasticity, we analyzed Arc/Arg3.1, known to control AMPA receptor trafficking, as well as regulators of tissue perfusion and energy consumption (NO-GC and GC-A). We observed that the changes in PPF of MRTMXcKOs mirrored the changes in their auditory nerve activity, whereas changes in the LTP of MRTMXcKOs and GRTMXcKOs mirrored instead the changes in their central compensation capacity. Enhanced GR expression levels in MRTMXcKOs suggest that MRs typically suppress GR expression. We observed that hippocampal LTP, GC-A mRNA expression levels, and ABR wave IV/I ratio were all enhanced in animals with elevated GR (MRTMXcKOs) but were all lower or not mobilized in animals with impaired GR expression levels (GRTMXcKOs and MRGRTMXcKOs). This suggests that GC-A may link LTP and auditory neural gain through GR-dependent processes. In addition, enhanced NO-GC expression levels in MR, GR, and MRGRTMXcKOs suggest that both receptors suppress NO-GC; on the other hand, elevated Arc/Arg3.1 levels in MRTMXcKOs and MRGRTMXcKOs but not GRTMXcKOs suggest that MR suppresses Arc/Arg3.1 expression levels. Conclusively, MR through GR inhibition may define the threshold for hemodynamic responses for LTP and auditory neural gain associated with GC-A.
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Affiliation(s)
- Dila Calis
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Morgan Hess
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Philine Marchetta
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Wibke Singer
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Julian Modro
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Ellis Nelissen
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, Netherlands
| | - Jos Prickaerts
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, Netherlands
| | - Peter Sandner
- Bayer Health Care Pharmaceuticals, Global Drug Discovery Pharma Research Centre Wuppertal, Wuppertal, Germany
| | - Robert Lukowski
- Institute of Pharmacy, Pharmacology, Toxicology and Clinical Pharmacy, University of Tübingen, Tübingen, Germany
| | - Peter Ruth
- Institute of Pharmacy, Pharmacology, Toxicology and Clinical Pharmacy, University of Tübingen, Tübingen, Germany
| | - Marlies Knipper
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Lukas Rüttiger
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
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23
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Diering GH. Remembering and forgetting in sleep: Selective synaptic plasticity during sleep driven by scaling factors Homer1a and Arc. Neurobiol Stress 2022; 22:100512. [PMID: 36632309 PMCID: PMC9826981 DOI: 10.1016/j.ynstr.2022.100512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 12/01/2022] [Accepted: 12/29/2022] [Indexed: 01/02/2023] Open
Abstract
Sleep is a conserved and essential process that supports learning and memory. Synapses are a major target of sleep function and a locus of sleep need. Evidence in the literature suggests that the need for sleep has a cellular or microcircuit level basis, and that sleep need can accumulate within localized brain regions as a function of waking activity. Activation of sleep promoting kinases and accumulation of synaptic phosphorylation was recently shown to be part of the molecular basis for the localized sleep need. A prominent hypothesis in the field suggests that some benefits of sleep are mediated by a broad but selective weakening, or scaling-down, of synaptic strength during sleep in order to offset increased excitability from synaptic potentiation during wake. The literature also shows that synapses can be strengthened during sleep, raising the question of what molecular mechanisms may allow for selection of synaptic plasticity types during sleep. Here I describe mechanisms of action of the scaling factors Arc and Homer1a in selective plasticity and links with sleep need. Arc and Homer1a are induced in neurons in response to waking neuronal activity and accumulate with time spent awake. I suggest that during sleep, Arc and Homer1a drive broad weakening of synapses through homeostatic scaling-down, but in a manner that is sensitive to the plasticity history of individual synapses, based on patterned phosphorylation of synaptic proteins. Therefore, Arc and Homer1a may offer insights into the intricate links between a cellular basis of sleep need and memory consolidation during sleep.
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Affiliation(s)
- Graham H. Diering
- Department of Cell Biology and Physiology and the UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA,Carolina Institute for Developmental Disabilities, USA,111 Mason Farm Road, 5200 Medical and Biomolecular Research Building, Chapel Hill, NC, 27599-7545, USA.
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24
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Sánchez-Castillo C, Cuartero MI, Fernández-Rodrigo A, Briz V, López-García S, Jiménez-Sánchez R, López JA, Graupera M, Esteban JA. Functional specialization of different PI3K isoforms for the control of neuronal architecture, synaptic plasticity, and cognition. SCIENCE ADVANCES 2022; 8:eabq8109. [PMID: 36417513 PMCID: PMC9683729 DOI: 10.1126/sciadv.abq8109] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 10/25/2022] [Indexed: 06/16/2023]
Abstract
Neuronal connectivity and activity-dependent synaptic plasticity are fundamental properties that support brain function and cognitive performance. Phosphatidylinositol 3-kinase (PI3K) intracellular signaling controls multiple mechanisms mediating neuronal growth, synaptic structure, and plasticity. However, it is still unclear how these pleiotropic functions are integrated at molecular and cellular levels. To address this issue, we used neuron-specific virally delivered Cre expression to delete either p110α or p110β (the two major catalytic isoforms of type I PI3K) from the hippocampus of adult mice. We found that dendritic and postsynaptic structures are almost exclusively supported by p110α activity, whereas p110β controls neurotransmitter release and metabotropic glutamate receptor-dependent long-term depression at the presynaptic terminal. In addition to these separate functions, p110α and p110β jointly contribute to N-methyl-d-aspartate receptor-dependent postsynaptic long-term potentiation. This molecular and functional specialization is reflected in different proteomes controlled by each isoform and in distinct behavioral alterations for learning/memory and sociability in mice lacking p110α or p110β.
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Affiliation(s)
- Carla Sánchez-Castillo
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
| | - María I. Cuartero
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
| | - Alba Fernández-Rodrigo
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
| | - Víctor Briz
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
| | - Sergio López-García
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
| | - Raquel Jiménez-Sánchez
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
| | - Juan A. López
- Proteomics Unit, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERCV), Instituto de Salud Carlos III, Madrid, Spain
| | - Mariona Graupera
- Endothelial Pathobiology and Microenviroment Group, Josep Carreras Leukaemia Research Institute (IJC), 08916 Badalona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Salud Carlos III, Madrid, Spain
| | - José A. Esteban
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
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25
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Development of single-molecule ubiquitination mediated fluorescence complementation to visualize protein ubiquitination dynamics in dendrites. Cell Rep 2022; 41:111658. [PMID: 36384114 PMCID: PMC9795412 DOI: 10.1016/j.celrep.2022.111658] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/13/2022] [Accepted: 10/21/2022] [Indexed: 11/17/2022] Open
Abstract
The ubiquitination/proteasome system is important for the spatiotemporal control of protein synthesis and degradation at synapses, while dysregulation may underlie autism spectrum disorders (ASDs). However, methods allowing direct visualization of the subcellular localization and temporal dynamics of protein ubiquitination are lacking. Here we report the development of Single-Molecule Ubiquitin Mediated Fluorescence Complementation (SM-UbFC) as a method to visualize and quantify the dynamics of protein ubiquitination in dendrites of live neurons in culture. Using SM-UbFC, we demonstrate that the rate of PSD-95 ubiquitination is elevated in dendrites of FMR1 KO neurons compared with wild-type controls. We further demonstrate the rapid ubiquitination of the fragile X messenger ribonucleoprotein, FMRP, and the AMPA receptor subunit, GluA1, which are known to be key events in the regulation of synaptic protein synthesis and plasticity. SM-UbFC will be useful for future studies on the regulation of synaptic protein homeostasis.
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26
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Eriksen MS, Bramham CR. Molecular physiology of Arc/Arg3.1: The oligomeric state hypothesis of synaptic plasticity. Acta Physiol (Oxf) 2022; 236:e13886. [PMID: 36073248 PMCID: PMC9787330 DOI: 10.1111/apha.13886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 08/15/2022] [Accepted: 09/05/2022] [Indexed: 01/29/2023]
Abstract
The immediate early gene, Arc, is a pivotal regulator of synaptic plasticity, memory, and cognitive flexibility. But what is Arc protein? How does it work? Inside the neuron, Arc is a protein interaction hub and dynamic regulator of intra-cellular signaling in synaptic plasticity. In remarkable contrast, Arc can also self-assemble into retrovirus-like capsids that are released in extracellular vesicles and capable of intercellular transfer of RNA. Elucidation of the molecular basis of Arc hub and capsid functions, and the relationship between them, is vital for progress. Here, we discuss recent findings on Arc structure-function and regulation of oligomerization that are giving insight into the molecular physiology of Arc. The unique features of mammalian Arc are emphasized, while drawing comparisons with Drosophila Arc and retroviral Gag. The Arc N-terminal domain, found only in mammals, is proposed to play a key role in regulating Arc hub signaling, oligomerization, and formation of capsids. Bringing together several lines of evidence, we hypothesize that Arc function in synaptic plasticity-long-term potentiation (LTP) and long-term depression (LTD)-are dictated by different oligomeric forms of Arc. Specifically, monomer/dimer function in LTP, tetramer function in basic LTD, and 32-unit oligomer function in enhanced LTD. The role of mammalian Arc capsids is unclear but likely depends on the cross-section of captured neuronal activity-induced RNAs. As the functional states of Arc are revealed, it may be possible to selectively manipulate specific forms of Arc-dependent plasticity and intercellular communication involved in brain function and dysfunction.
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Affiliation(s)
| | - Clive R. Bramham
- Department of BiomedicineUniversity of BergenBergenNorway,Mohn Research Center for the BrainUniversity of BergenBergenNorway
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27
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Privitera L, Hogg EL, Lopes M, Domingos LB, Gaestel M, Müller J, Wall MJ, Corrêa SAL. The MK2 cascade mediates transient alteration in mGluR-LTD and spatial learning in a murine model of Alzheimer's disease. Aging Cell 2022; 21:e13717. [PMID: 36135933 PMCID: PMC9577942 DOI: 10.1111/acel.13717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 08/05/2022] [Accepted: 08/29/2022] [Indexed: 01/25/2023] Open
Abstract
A key aim of Alzheimer disease research is to develop efficient therapies to prevent and/or delay the irreversible progression of cognitive impairments. Early deficits in long-term potentiation (LTP) are associated with the accumulation of amyloid beta in rodent models of the disease; however, less is known about how mGluR-mediated long-term depression (mGluR-LTD) is affected. In this study, we have found that mGluR-LTD is enhanced in the APPswe /PS1dE9 mouse at 7 but returns to wild-type levels at 13 months of age. This transient over-activation of mGluR signalling is coupled with impaired LTP and shifts the dynamic range of synapses towards depression. These alterations in synaptic plasticity are associated with an inability to utilize cues in a spatial learning task. The transient dysregulation of plasticity can be prevented by genetic deletion of the MAP kinase-activated protein kinase 2 (MK2), a substrate of p38 MAPK, demonstrating that manipulating the mGluR-p38 MAPK-MK2 cascade at 7 months can prevent the shift in synapse dynamic range. Our work reveals the MK2 cascade as a potential pharmacological target to correct the over-activation of mGluR signalling.
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Affiliation(s)
- Lucia Privitera
- Bradford School of Pharmacy and Medical SciencesUniversity of BradfordBradfordUK,School of Medicine, Ninewells HospitalUniversity of DundeeDundeeUK,Barts and the London School of MedicineQueen Mary University of London Malta CampusVictoriaMalta
| | - Ellen L. Hogg
- Bradford School of Pharmacy and Medical SciencesUniversity of BradfordBradfordUK
| | - Marcia Lopes
- Bradford School of Pharmacy and Medical SciencesUniversity of BradfordBradfordUK
| | - Luana B. Domingos
- Bradford School of Pharmacy and Medical SciencesUniversity of BradfordBradfordUK
| | - Matthias Gaestel
- Institute of Cell BiochemistryHannover Medical UniversityHannoverGermany
| | - Jürgen Müller
- Bradford School of Pharmacy and Medical SciencesUniversity of BradfordBradfordUK
| | - Mark J. Wall
- School of Life SciencesUniversity of WarwickCoventryUK
| | - Sonia A. L. Corrêa
- Bradford School of Pharmacy and Medical SciencesUniversity of BradfordBradfordUK,Faculty of Science and EngineeringManchester Metropolitan UniversityManchesterUK
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28
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Chen X, Jia B, Araki Y, Liu B, Ye F, Huganir R, Zhang M. Arc weakens synapses by dispersing AMPA receptors from postsynaptic density via modulating PSD phase separation. Cell Res 2022; 32:914-930. [PMID: 35856091 PMCID: PMC9525282 DOI: 10.1038/s41422-022-00697-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 06/29/2022] [Indexed: 01/16/2023] Open
Abstract
In response to stimuli, the immediate early gene product Arc can acutely down-regulate synaptic strength by removing AMPA receptors (AMPARs) from synapses and thus regulate synaptic plasticity. How Arc, a scaffold protein, can specifically facilitate synaptic removal of AMPARs is unknown. We found that Arc directly antagonizes with PSD-95 in binding to TARPs, which are the auxiliary subunits of AMPARs. Arc, in a highly concentration-sensitive manner, acutely disperses TARPs from the postsynaptic density (PSD) condensate formed via phase separation. TARPs with the Ser residue in the "P-S-Y"-motif of its tail phosphorylated are completely refractory from being dispersed by Arc, suggesting that Arc cannot displace AMPARs from PSDs in active synapses. Conversely, strengthening the interaction between Arc and TARPs enhances Arc's capacity in weakening synapses. Thus, Arc can specifically and effectively modulate synaptic AMPAR clustering via modulating PSD phase separation. Our study further suggests that activity-dependent, bi-directional modulation of PSD condensate formation/dispersion represents a general regulatory mechanism for synaptic plasticity.
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Affiliation(s)
- Xudong Chen
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Bowen Jia
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Yoichi Araki
- Department of Neuroscience and Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Bian Liu
- Department of Neuroscience and Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Fei Ye
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Richard Huganir
- Department of Neuroscience and Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mingjie Zhang
- Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
- School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, China.
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29
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Ojeda-Juárez D, Lawrence JA, Soldau K, Pizzo DP, Wheeler E, Aguilar-Calvo P, Khuu H, Chen J, Malik A, Funk G, Nam P, Sanchez H, Geschwind MD, Wu C, Yeo GW, Chen X, Patrick GN, Sigurdson CJ. Prions induce an early Arc response and a subsequent reduction in mGluR5 in the hippocampus. Neurobiol Dis 2022; 172:105834. [PMID: 35905927 PMCID: PMC10080886 DOI: 10.1016/j.nbd.2022.105834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 07/22/2022] [Accepted: 07/22/2022] [Indexed: 12/01/2022] Open
Abstract
Synapse dysfunction and loss are central features of neurodegenerative diseases, caused in part by the accumulation of protein oligomers. Amyloid-β, tau, prion, and α-synuclein oligomers bind to the cellular prion protein (PrPC), resulting in the activation of macromolecular complexes and signaling at the post-synapse, yet the early signaling events are unclear. Here we sought to determine the early transcript and protein alterations in the hippocampus during the pre-clinical stages of prion disease. We used a transcriptomic approach focused on the early-stage, prion-infected hippocampus of male wild-type mice, and identify immediate early genes, including the synaptic activity response gene, Arc/Arg3.1, as significantly upregulated. In a longitudinal study of male, prion-infected mice, Arc/Arg-3.1 protein was increased early (40% of the incubation period), and by mid-disease (pre-clinical), phosphorylated AMPA receptors (pGluA1-S845) were increased and metabotropic glutamate receptors (mGluR5 dimers) were markedly reduced in the hippocampus. Notably, sporadic Creutzfeldt-Jakob disease (sCJD) post-mortem cortical samples also showed low levels of mGluR5 dimers. Together, these findings suggest that prions trigger an early Arc response, followed by an increase in phosphorylated GluA1 and a reduction in mGluR5 receptors.
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Affiliation(s)
- Daniel Ojeda-Juárez
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Jessica A Lawrence
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Katrin Soldau
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Donald P Pizzo
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Emily Wheeler
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | | | - Helen Khuu
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Joy Chen
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Adela Malik
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Gail Funk
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Percival Nam
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Henry Sanchez
- Department of Pathology, Division of Neuropathology, University of California San Francisco, San Francisco, CA, USA
| | - Michael D Geschwind
- Department of Neurology, Weill Institute for Neurosciences, Memory and Aging Center, University of California San Francisco, San Francisco, CA, USA
| | - Chengbiao Wu
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Xu Chen
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Gentry N Patrick
- Division of Biological Sciences, Section of Neurobiology, University of California San Diego, La Jolla, CA, USA
| | - Christina J Sigurdson
- Department of Pathology, University of California San Diego, La Jolla, CA, USA; Department of Medicine, University of California San Diego, La Jolla, CA, USA; Department of Pathology, Microbiology and Immunology, University of California Davis, Davis, CA, USA.
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30
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Real-time imaging of Arc/Arg3.1 transcription ex vivo reveals input-specific immediate early gene dynamics. Proc Natl Acad Sci U S A 2022; 119:e2123373119. [PMID: 36095210 PMCID: PMC9499544 DOI: 10.1073/pnas.2123373119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ability of neurons to process and store salient environmental features underlies information processing in the brain. Long-term information storage requires synaptic plasticity and regulation of gene expression. While distinct patterns of activity have been linked to synaptic plasticity, their impact on immediate early gene (IEG) expression remains poorly understood. The activity regulated cytoskeleton associated (Arc) gene has received wide attention as an IEG critical for long-term synaptic plasticity and memory. Yet, to date, the transcriptional dynamics of Arc in response to compartment and input-specific activity is unclear. By developing a knock-in mouse to fluorescently tag Arc alleles, we studied real-time transcription dynamics after stimulation of dentate granule cells (GCs) in acute hippocampal slices. To our surprise, we found that Arc transcription displayed distinct temporal kinetics depending on the activation of excitatory inputs that convey functionally distinct information, i.e., medial and lateral perforant paths (MPP and LPP, respectively). Moreover, the transcriptional dynamics of Arc after synaptic stimulation was similar to direct activation of GCs, although the contribution of ionotropic glutamate receptors, L-type voltage-gated calcium channel, and the endoplasmic reticulum (ER) differed. Specifically, we observed an ER-mediated synapse-to-nucleus signal that supported elevations in nuclear calcium and, thereby, rapid induction of Arc transcription following MPP stimulation. By delving into the complex excitation-transcription coupling for Arc, our findings highlight how different synaptic inputs may encode information by modulating transcription dynamics of an IEG linked to learning and memory.
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31
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Myrum C, Moreno-Castilla P, Rapp PR. 'Arc'-hitecture of normal cognitive aging. Ageing Res Rev 2022; 80:101678. [PMID: 35781092 PMCID: PMC9378697 DOI: 10.1016/j.arr.2022.101678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 06/10/2022] [Accepted: 06/24/2022] [Indexed: 12/17/2022]
Abstract
Arc is an effector immediate-early gene that is critical for forming long-term memories. Since its discovery 25 years ago, it has repeatedly surprised us with a number of intriguing properties, including the transport of its mRNA to recently-activated synapses, its master role in bidirectionally regulating synaptic strength, its evolutionary retroviral origins, its ability to mediate intercellular transfer between neurons via extracellular vesicles (EVs), and its exceptional regulation-both temporally and spatially. The current review discusses how Arc has been used as a tool to identify the neural networks involved in cognitive aging and how Arc itself may contribute to cognitive outcome in aging. In addition, we raise several outstanding questions, including whether Arc-containing EVs in peripheral blood might provide a noninvasive biomarker for memory-related synaptic failure in aging, and whether rectifying Arc dysregulation is likely to be an effective strategy for bending the arc of aging toward successful cognitive outcomes.
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Affiliation(s)
- Craig Myrum
- Neurocognitive Aging Section, Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
| | - Perla Moreno-Castilla
- Neurocognitive Aging Section, Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
| | - Peter R Rapp
- Neurocognitive Aging Section, Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
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32
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Leung HW, Foo G, VanDongen A. Arc Regulates Transcription of Genes for Plasticity, Excitability and Alzheimer’s Disease. Biomedicines 2022; 10:biomedicines10081946. [PMID: 36009494 PMCID: PMC9405677 DOI: 10.3390/biomedicines10081946] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/21/2022] [Accepted: 07/25/2022] [Indexed: 02/06/2023] Open
Abstract
The immediate early gene Arc is a master regulator of synaptic function and a critical determinant of memory consolidation. Here, we show that Arc interacts with dynamic chromatin and closely associates with histone markers for active enhancers and transcription in cultured rat hippocampal neurons. Both these histone modifications, H3K27Ac and H3K9Ac, have recently been shown to be upregulated in late-onset Alzheimer’s disease (AD). When Arc induction by pharmacological network activation was prevented using a short hairpin RNA, the expression profile was altered for over 1900 genes, which included genes associated with synaptic function, neuronal plasticity, intrinsic excitability, and signalling pathways. Interestingly, about 100 Arc-dependent genes are associated with the pathophysiology of AD. When endogenous Arc expression was induced in HEK293T cells, the transcription of many neuronal genes was increased, suggesting that Arc can control expression in the absence of activated signalling pathways. Taken together, these data establish Arc as a master regulator of neuronal activity-dependent gene expression and suggest that it plays a significant role in the pathophysiology of AD.
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Affiliation(s)
| | - Gabriel Foo
- Duke-NUS Medical School, Singapore 169857, Singapore
| | - Antonius VanDongen
- Duke-NUS Medical School, Singapore 169857, Singapore
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC 27710, USA
- Correspondence:
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33
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Mahringer D, Zmarz P, Okuno H, Bito H, Keller GB. Functional correlates of immediate early gene expression in mouse visual cortex. PEER COMMUNITY JOURNAL 2022; 2:e45. [PMID: 37091727 PMCID: PMC7614465 DOI: 10.24072/pcjournal.156] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
During visual development, response properties of layer 2/3 neurons in visual cortex are shaped by experience. Both visual and visuomotor experience are necessary to co-ordinate the integration of bottom-up visual input and top-down motor-related input. Whether visual and visuomotor experience engage different plasticity mechanisms, possibly associated with the two separate input pathways, is still unclear. To begin addressing this, we measured the expression level of three different immediate early genes (IEG) (c-fos, egr1 or Arc) and neuronal activity in layer 2/3 neurons of visual cortex before and after a mouse's first visual exposure in life, and subsequent visuomotor learning. We found that expression levels of all three IEGs correlated positively with neuronal activity, but that first visual and first visuomotor exposure resulted in differential changes in IEG expression patterns. In addition, IEG expression levels differed depending on whether neurons exhibited primarily visually driven or motor-related activity. Neurons with strong motor-related activity preferentially expressed EGR1, while neurons that developed strong visually driven activity preferentially expressed Arc. Our findings are consistent with the interpretation that bottom-up visual input and top-down motor-related input are associated with different IEG expression patterns and hence possibly also with different plasticity pathways.
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Affiliation(s)
- David Mahringer
- Faculty of Natural Sciences, University of Basel, Basel, Switzerland
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Pawel Zmarz
- Faculty of Natural Sciences, University of Basel, Basel, Switzerland
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Hiroyuki Okuno
- Department of Biochemistry and Molecular Biology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Kagoshima 890-8544, Japan
| | - Haruhiko Bito
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Georg B Keller
- Faculty of Natural Sciences, University of Basel, Basel, Switzerland
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
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34
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Lee CW, Hsu LF, Wu IL, Wang YL, Chen WC, Liu YJ, Yang LT, Tan CL, Luo YH, Wang CC, Chiu HW, Yang TCK, Lin YY, Chang HA, Chiang YC, Chen CH, Lee MH, Peng KT, Huang CCY. Exposure to polystyrene microplastics impairs hippocampus-dependent learning and memory in mice. JOURNAL OF HAZARDOUS MATERIALS 2022; 430:128431. [PMID: 35150991 DOI: 10.1016/j.jhazmat.2022.128431] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 01/24/2022] [Accepted: 02/02/2022] [Indexed: 06/14/2023]
Abstract
Microplastics (MPs) pollution has become a serious environmental issue worldwide, but its potential effects on health remain unknown. The administration of polystyrene MPs (PS-MPs) to mice for eight weeks impaired learning and memory behavior. PS-MPs were detected in the brain especially in the hippocampus of these mice. Concurrently, the hippocampus had decreased levels of immediate-early genes, aberrantly enhanced synaptic glutamate AMPA receptors, and elevated neuroinflammation, all of which are critical for synaptic plasticity and memory. Interestingly, ablation of the vagus nerve, a modulator of the gut-brain axis, improved the memory function of PS-MPs mice. These results indicate that exposure to PS-MPs in mice alters the expression of neuronal activity-dependent genes and synaptic proteins, and increases neuroinflammation in the hippocampus, subsequently causing behavioral changes through the vagus nerve-dependent pathway. Our findings shed light on the adverse impacts of PS-MPs on the brain and hippocampal learning and memory.
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Affiliation(s)
- Chiang-Wen Lee
- Department of Nursing, Division of Basic Medical Sciences, and Chronic Diseases and Health Promotion Research Center, Chang Gung University of Science and Technology, Puzi City, Chiayi County 61363, Taiwan; Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, Puzi City, Chiayi County 61363, Taiwan; Department of Safety Health and Environmental Engineering, Ming Chi University of Technology, New Taipei City 243303, Taiwan
| | - Lee-Fen Hsu
- Department of Respiratory Care, Chang Gung University of Science and Technology, Puzi City, Chiayi County 613, Taiwan; Division of Neurosurgery, Department of Surgery, Chang Gung Memorial Hospital, Puzi City, Chiayi County 613, Taiwan
| | - I-Lin Wu
- Department of Emergency Medicine, Taoyuan Armed Forces General Hospital, Taoyuan, Taiwan
| | - Yung-Li Wang
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan
| | - Wei-Chen Chen
- Department of Life Sciences, National Central University, Taoyuan, Taiwan
| | - Yan-Jun Liu
- Department of Life Sciences, National Central University, Taoyuan, Taiwan
| | - Lu-Tang Yang
- Department of Life Sciences, National Central University, Taoyuan, Taiwan
| | - Chong-Lun Tan
- Department of Life Sciences, National Central University, Taoyuan, Taiwan
| | - Yueh-Hsia Luo
- Department of Life Sciences, National Central University, Taoyuan, Taiwan
| | | | - Hui-Wen Chiu
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan; Department of Medical Research, Shuang Ho Hospital, Taipei Medical University, New Taipei City 235, Taiwan
| | - Thomas Chung-Kuang Yang
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan
| | - Yen-Yue Lin
- Department of Emergency Medicine, Taoyuan Armed Forces General Hospital, Taoyuan, Taiwan; Department of Life Sciences, National Central University, Taoyuan, Taiwan
| | - Hsin-An Chang
- Department of Psychiatry, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Yao-Chang Chiang
- Department of Nursing, Division of Basic Medical Sciences, and Chronic Diseases and Health Promotion Research Center, Chang Gung University of Science and Technology, Puzi City, Chiayi County 61363, Taiwan
| | | | - Ming-Hsueh Lee
- Division of Neurosurgery, Department of Surgery, Chang Gung Memorial Hospital, Puzi City, Chiayi County 613, Taiwan
| | - Kuo-Ti Peng
- Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, Puzi City, Chiayi County 61363, Taiwan; College of Medicine, Chang Gung University, Guishan Dist., Taoyuan City 33303, Taiwan
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35
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Oliveira MM, Klann E. eIF2-dependent translation initiation: Memory consolidation and disruption in Alzheimer's disease. Semin Cell Dev Biol 2022; 125:101-109. [PMID: 34304995 PMCID: PMC8782933 DOI: 10.1016/j.semcdb.2021.07.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 06/20/2021] [Accepted: 07/12/2021] [Indexed: 01/05/2023]
Abstract
Memory storage is a conserved survivability feature, present in virtually any complex species. During the last few decades, much effort has been devoted to understanding how memories are formed and which molecular switches define whether a memory should be stored for a short or a long period of time. Among these, de novo protein synthesis is known to be required for the conversion of short- to long-term memory. There are a number translational control pathways involved in synaptic plasticity and memory consolidation, including the phosphorylation of the eukaryotic initiation factor 2 alpha (eIF2α), which has emerged as a critical molecular switch for long-term memory consolidation. In this review, we discuss findings pertaining to the requirement of de novo protein synthesis to memory formation, how local dendritic and axonal translation is regulated in neurons, and how these can influence memory consolidation. We also highlight the importance of eIF2α-dependent translation initiation to synaptic plasticity and memory formation. Finally, we contextualize how aberrant phosphorylation of eIF2α contributes to Alzheimer's disease (AD) pathology and how preventing disruption of eIF2-dependent translation may be a therapeutic avenue for preventing and/or restoring memory loss in AD.
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Affiliation(s)
| | - Eric Klann
- Center for Neural Science, New York University, New York, NY, USA; NYU Neuroscience Institute, New York University Grossman School of Medicine, New York, NY, USA.
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36
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Development and Validation of Arc Nanobodies: New Tools for Probing Arc Dynamics and Function. Neurochem Res 2022; 47:2656-2666. [PMID: 35307777 PMCID: PMC9463278 DOI: 10.1007/s11064-022-03573-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/04/2022] [Accepted: 03/07/2022] [Indexed: 11/06/2022]
Abstract
Activity-regulated cytoskeleton-associated (Arc) protein plays key roles in long-term synaptic plasticity, memory, and cognitive flexibility. However, an integral understanding of Arc mechanisms is lacking. Arc is proposed to function as an interaction hub in neuronal dendrites and the nucleus, yet Arc can also form retrovirus-like capsids with proposed roles in intercellular communication. Here, we sought to develop anti-Arc nanobodies (ArcNbs) as new tools for probing Arc dynamics and function. Six ArcNbs representing different clonal lines were selected from immunized alpaca. Immunoblotting with recombinant ArcNbs fused to a small ALFA-epitope tag demonstrated binding to recombinant Arc as well as endogenous Arc from rat cortical tissue. ALFA-tagged ArcNb also provided efficient immunoprecipitation of stimulus-induced Arc after carbachol-treatment of SH-SY5Y neuroblastoma cells and induction of long-term potentiation in the rat dentate gyrus in vivo. Epitope mapping showed that all Nbs recognize the Arc C-terminal region containing the retroviral Gag capsid homology domain, comprised of tandem N- and C-lobes. ArcNbs E5 and H11 selectively bound the N-lobe, which harbors a peptide ligand binding pocket specific to mammals. Four additional ArcNbs bound the region containing the C-lobe and C-terminal tail. For use as genetically encoded fluorescent intrabodies, we show that ArcNbs fused to mScarlet-I are uniformly expressed, without aggregation, in the cytoplasm and nucleus of HEK293FT cells. Finally, mScarlet-I-ArcNb H11 expressed as intrabody selectively bound the N-lobe and enabled co-immunoprecipitation of full-length intracellular Arc. ArcNbs are versatile tools for live-cell labeling and purification of Arc, and interrogation of Arc capsid domain specific functions.
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37
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Kallergi E, Daskalaki AD, Kolaxi A, Camus C, Ioannou E, Mercaldo V, Haberkant P, Stein F, Sidiropoulou K, Dalezios Y, Savitski MM, Bagni C, Choquet D, Hosy E, Nikoletopoulou V. Dendritic autophagy degrades postsynaptic proteins and is required for long-term synaptic depression in mice. Nat Commun 2022; 13:680. [PMID: 35115539 PMCID: PMC8814153 DOI: 10.1038/s41467-022-28301-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 01/14/2022] [Indexed: 01/18/2023] Open
Abstract
The pruning of dendritic spines during development requires autophagy. This process is facilitated by long-term depression (LTD)-like mechanisms, which has led to speculation that LTD, a fundamental form of synaptic plasticity, also requires autophagy. Here, we show that the induction of LTD via activation of NMDA receptors or metabotropic glutamate receptors initiates autophagy in the postsynaptic dendrites in mice. Dendritic autophagic vesicles (AVs) act in parallel with the endocytic machinery to remove AMPA receptor subunits from the membrane for degradation. During NMDAR-LTD, key postsynaptic proteins are sequestered for autophagic degradation, as revealed by quantitative proteomic profiling of purified AVs. Pharmacological inhibition of AV biogenesis, or conditional ablation of atg5 in pyramidal neurons abolishes LTD and triggers sustained potentiation in the hippocampus. These deficits in synaptic plasticity are recapitulated by knockdown of atg5 specifically in postsynaptic pyramidal neurons in the CA1 area. Conducive to the role of synaptic plasticity in behavioral flexibility, mice with autophagy deficiency in excitatory neurons exhibit altered response in reversal learning. Therefore, local assembly of the autophagic machinery in dendrites ensures the degradation of postsynaptic components and facilitates LTD expression.
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Affiliation(s)
- Emmanouela Kallergi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, 1005, Switzerland
| | | | - Angeliki Kolaxi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, 1005, Switzerland
| | - Come Camus
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Evangelia Ioannou
- School of Biological Sciences, University of Crete, Heraklion, 70013, Greece
| | - Valentina Mercaldo
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, 1005, Switzerland
| | - Per Haberkant
- Proteomic Core Facility (PCF), European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Frank Stein
- Proteomic Core Facility (PCF), European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | | | - Yannis Dalezios
- School of Medicine, University of Crete, Heraklion, 71003, Greece
- Institute of Applied and Computational Mathematics (IACM), Foundation for Research and Technology-Hellas (FORTH), Heraklion, Greece
| | - Mikhail M Savitski
- Proteomic Core Facility (PCF), European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), University of Rome Tor Vergata, Rome, 00133, Italy
| | - Claudia Bagni
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, 1005, Switzerland
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, Rome, 00133, Italy
| | - Daniel Choquet
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, F-33000, Bordeaux, France
| | - Eric Hosy
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
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38
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Catsburg LAE, Westra M, van Schaik AML, MacGillavry HD. Dynamics and nanoscale organization of the postsynaptic endocytic zone at excitatory synapses. eLife 2022; 11:74387. [PMID: 35072626 PMCID: PMC8813055 DOI: 10.7554/elife.74387] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 11/07/2021] [Indexed: 12/01/2022] Open
Abstract
At postsynaptic sites of neurons, a prominent clathrin-coated structure, the endocytic zone (EZ), controls the trafficking of glutamate receptors and is essential for synaptic plasticity. Despite its importance, little is known about how this clathrin structure is organized to mediate endocytosis. We used live-cell and super-resolution microscopy to reveal the dynamic organization of this poorly understood clathrin structure in rat hippocampal neurons. We found that a subset of endocytic proteins only transiently appeared at postsynaptic sites. In contrast, other proteins were persistently enriched and partitioned at the edge of the EZ. We found that uncoupling the EZ from the synapse led to the loss of most of these components, while disrupting interactions with the actin cytoskeleton or membrane did not alter EZ positioning. Finally, we found that plasticity-inducing stimuli promoted the reorganization of the EZ. We conclude that the EZ is a stable, highly organized molecular platform where components are differentially recruited and positioned to orchestrate the endocytosis of synaptic receptors.
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39
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Knipper M, Singer W, Schwabe K, Hagberg GE, Li Hegner Y, Rüttiger L, Braun C, Land R. Disturbed Balance of Inhibitory Signaling Links Hearing Loss and Cognition. Front Neural Circuits 2022; 15:785603. [PMID: 35069123 PMCID: PMC8770933 DOI: 10.3389/fncir.2021.785603] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/08/2021] [Indexed: 12/19/2022] Open
Abstract
Neuronal hyperexcitability in the central auditory pathway linked to reduced inhibitory activity is associated with numerous forms of hearing loss, including noise damage, age-dependent hearing loss, and deafness, as well as tinnitus or auditory processing deficits in autism spectrum disorder (ASD). In most cases, the reduced central inhibitory activity and the accompanying hyperexcitability are interpreted as an active compensatory response to the absence of synaptic activity, linked to increased central neural gain control (increased output activity relative to reduced input). We here suggest that hyperexcitability also could be related to an immaturity or impairment of tonic inhibitory strength that typically develops in an activity-dependent process in the ascending auditory pathway with auditory experience. In these cases, high-SR auditory nerve fibers, which are critical for the shortest latencies and lowest sound thresholds, may have either not matured (possibly in congenital deafness or autism) or are dysfunctional (possibly after sudden, stressful auditory trauma or age-dependent hearing loss linked with cognitive decline). Fast auditory processing deficits can occur despite maintained basal hearing. In that case, tonic inhibitory strength is reduced in ascending auditory nuclei, and fast inhibitory parvalbumin positive interneuron (PV-IN) dendrites are diminished in auditory and frontal brain regions. This leads to deficits in central neural gain control linked to hippocampal LTP/LTD deficiencies, cognitive deficits, and unbalanced extra-hypothalamic stress control. Under these conditions, a diminished inhibitory strength may weaken local neuronal coupling to homeostatic vascular responses required for the metabolic support of auditory adjustment processes. We emphasize the need to distinguish these two states of excitatory/inhibitory imbalance in hearing disorders: (i) Under conditions of preserved fast auditory processing and sustained tonic inhibitory strength, an excitatory/inhibitory imbalance following auditory deprivation can maintain precise hearing through a memory linked, transient disinhibition that leads to enhanced spiking fidelity (central neural gain⇑) (ii) Under conditions of critically diminished fast auditory processing and reduced tonic inhibitory strength, hyperexcitability can be part of an increased synchronization over a broader frequency range, linked to reduced spiking reliability (central neural gain⇓). This latter stage mutually reinforces diminished metabolic support for auditory adjustment processes, increasing the risks for canonical dementia syndromes.
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Affiliation(s)
- Marlies Knipper
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center (THRC), Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
- *Correspondence: Marlies Knipper,
| | - Wibke Singer
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center (THRC), Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Kerstin Schwabe
- Experimental Neurosurgery, Department of Neurosurgery, Hannover Medical School, Hanover, Germany
| | - Gisela E. Hagberg
- Department of Biomedical Magnetic Resonance, University Hospital Tübingen (UKT), Tübingen, Germany
- High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Yiwen Li Hegner
- MEG Center, University of Tübingen, Tübingen, Germany
- Center of Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Lukas Rüttiger
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center (THRC), Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Christoph Braun
- MEG Center, University of Tübingen, Tübingen, Germany
- Center of Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Rüdiger Land
- Department of Experimental Otology, Institute for Audioneurotechnology, Hannover Medical School, Hanover, Germany
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40
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Jenks KR, Tsimring K, Ip JPK, Zepeda JC, Sur M. Heterosynaptic Plasticity and the Experience-Dependent Refinement of Developing Neuronal Circuits. Front Neural Circuits 2021; 15:803401. [PMID: 34949992 PMCID: PMC8689143 DOI: 10.3389/fncir.2021.803401] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 11/15/2021] [Indexed: 01/01/2023] Open
Abstract
Neurons remodel the structure and strength of their synapses during critical periods of development in order to optimize both perception and cognition. Many of these developmental synaptic changes are thought to occur through synapse-specific homosynaptic forms of experience-dependent plasticity. However, homosynaptic plasticity can also induce or contribute to the plasticity of neighboring synapses through heterosynaptic interactions. Decades of research in vitro have uncovered many of the molecular mechanisms of heterosynaptic plasticity that mediate local compensation for homosynaptic plasticity, facilitation of further bouts of plasticity in nearby synapses, and cooperative induction of plasticity by neighboring synapses acting in concert. These discoveries greatly benefited from new tools and technologies that permitted single synapse imaging and manipulation of structure, function, and protein dynamics in living neurons. With the recent advent and application of similar tools for in vivo research, it is now feasible to explore how heterosynaptic plasticity contribute to critical periods and the development of neuronal circuits. In this review, we will first define the forms heterosynaptic plasticity can take and describe our current understanding of their molecular mechanisms. Then, we will outline how heterosynaptic plasticity may lead to meaningful refinement of neuronal responses and observations that suggest such mechanisms are indeed at work in vivo. Finally, we will use a well-studied model of cortical plasticity—ocular dominance plasticity during a critical period of visual cortex development—to highlight the molecular overlap between heterosynaptic and developmental forms of plasticity, and suggest potential avenues of future research.
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Affiliation(s)
- Kyle R Jenks
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Katya Tsimring
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Jacque Pak Kan Ip
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Jose C Zepeda
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Mriganka Sur
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
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41
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Reyes-Resina I, Samer S, Kreutz MR, Oelschlegel AM. Molecular Mechanisms of Memory Consolidation That Operate During Sleep. Front Mol Neurosci 2021; 14:767384. [PMID: 34867190 PMCID: PMC8636908 DOI: 10.3389/fnmol.2021.767384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 10/27/2021] [Indexed: 11/17/2022] Open
Abstract
The role of sleep for brain function has been in the focus of interest for many years. It is now firmly established that sleep and the corresponding brain activity is of central importance for memory consolidation. Less clear are the underlying molecular mechanisms and their specific contribution to the formation of long-term memory. In this review, we summarize the current knowledge of such mechanisms and we discuss the several unknowns that hinder a deeper appreciation of how molecular mechanisms of memory consolidation during sleep impact synaptic function and engram formation.
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Affiliation(s)
- Irene Reyes-Resina
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Sebastian Samer
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Michael R Kreutz
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Leibniz Group 'Dendritic Organelles and Synaptic Function', Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Center for Behavioral Brain Sciences, Otto von Guericke University, Magdeburg, Germany.,German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Anja M Oelschlegel
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
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42
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Membrane trafficking and positioning of mGluRs at presynaptic and postsynaptic sites of excitatory synapses. Neuropharmacology 2021; 200:108799. [PMID: 34592242 DOI: 10.1016/j.neuropharm.2021.108799] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 08/31/2021] [Accepted: 09/17/2021] [Indexed: 01/21/2023]
Abstract
The plethora of functions of glutamate in the brain are mediated by the complementary actions of ionotropic and metabotropic glutamate receptors (mGluRs). The ionotropic glutamate receptors carry most of the fast excitatory transmission, while mGluRs modulate transmission on longer timescales by triggering multiple intracellular signaling pathways. As such, mGluRs mediate critical aspects of synaptic transmission and plasticity. Interestingly, at synapses, mGluRs operate at both sides of the cleft, and thus bidirectionally exert the effects of glutamate. At postsynaptic sites, group I mGluRs act to modulate excitability and plasticity. At presynaptic sites, group II and III mGluRs act as auto-receptors, modulating release properties in an activity-dependent manner. Thus, synaptic mGluRs are essential signal integrators that functionally couple presynaptic and postsynaptic mechanisms of transmission and plasticity. Understanding how these receptors reach the membrane and are positioned relative to the presynaptic glutamate release site are therefore important aspects of synapse biology. In this review, we will discuss the currently known mechanisms underlying the trafficking and positioning of mGluRs at and around synapses, and how these mechanisms contribute to synaptic functioning. We will highlight outstanding questions and present an outlook on how recent technological developments will move this exciting research field forward.
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43
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Vadakkan KI. Framework for internal sensation of pleasure using constraints from disparate findings in nucleus accumbens. World J Psychiatry 2021; 11:681-695. [PMID: 34733636 PMCID: PMC8546768 DOI: 10.5498/wjp.v11.i10.681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/27/2021] [Accepted: 09/02/2021] [Indexed: 02/06/2023] Open
Abstract
It is necessary to find a mechanism that generates first-person inner sensation of pleasure to understand what causes addiction and associated behaviour by drugs of abuse. The actual mechanism is expected to explain several disparate findings in nucleus accumbens (NAc), a brain region associated with pleasure, in an interconnected manner. Previously, it was possible to derive a mechanism for natural learning and explain: (1) Generation of inner sensation of memory using changes generated by learning; and (2) Long-term potentiation as an experimental delayed scaled-up change by the same mechanism that occur during natural learning. By extending these findings and by using disparate third person observations in NAc from several studies, present work provides a framework of a mechanism that generates internal sensation of pleasure that can provide interconnected explanations for: (1) Ability to induce robust long-term depression (LTD) in NAc from naïve animals; (2) Impaired ability to induce LTD in “addicted” state; (3) Attenuation of postsynaptic potentials by cocaine; and (4) Reduced firing of medium spiny neurons in response to cocaine or dopamine. Findings made by this work are testable.
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44
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McReynolds JR, Carreira MB, McIntyre CK. Post-training intra-basolateral complex of the amygdala infusions of clenbuterol enhance memory for conditioned place preference and increase ARC protein expression in dorsal hippocampal synaptic fractions. Neurobiol Learn Mem 2021; 185:107539. [PMID: 34648950 DOI: 10.1016/j.nlm.2021.107539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 09/23/2021] [Accepted: 10/07/2021] [Indexed: 11/19/2022]
Abstract
The basolateral complex of the amygdala (BLA) is critically involved in modulation of memory by stress hormones. Noradrenergic activation of the BLA enhances memory consolidation and plays a necessary role in the enhancing or impairing effects of stress hormones on memory. The BLA is not only involved in the consolidation of aversive memories but can regulate appetitive memory formation as well. Extensive evidence suggests that the BLA is a modulatory structure that influences consolidation of arousing memories through modulation of plasticity and expression of plasticity-related genes, such as the activity regulated cytoskeletal-associated (Arc/Arg 3.1) protein, in efferent brain regions. ARC is an immediate early gene whose mRNA is localized to the dendrites and is necessary for hippocampus-dependent long-term potentiation and long-term memory formation. Post-training intra-BLA infusions of the β-adrenoceptor agonist, clenbuterol, enhances memory for an aversive task and increases dorsal hippocampus ARC protein expression following training on that task. To examine whether this function of BLA noradrenergic signaling extends to the consolidation of appetitive memories, the present studies test the effect of post-training intra-BLA infusions of clenbuterol on memory for the appetitive conditioned place preference (CPP) task and for effects on ARC protein expression in hippocampal synapses. Additionally, the necessity of increased hippocampal ARC protein expression was also examined for long-term memory formation of the CPP task. Immediate post-training intra-BLA infusions of clenbuterol (4 ng/0.2 µL) significantly enhanced memory for the CPP task. This same memory enhancing treatment significantly increased ARC protein expression in dorsal, but not ventral, hippocampal synaptic fractions. Furthermore, immediate post-training intra-dorsal hippocampal infusions of Arc antisense oligodeoxynucleotides (ODNs), which reduce ARC protein expression, prevented long-term memory formation for the CPP task. These results suggest that noradrenergic activity in the BLA influences long-term memory for aversive and appetitive events in a similar manner and the role of the BLA is conserved across classes of memory. It also suggests that the influence of the BLA on hippocampal ARC protein expression and the role of hippocampal ARC protein expression are conserved across classes of emotionally arousing memories.
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Affiliation(s)
- Jayme R McReynolds
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX 75080, United States.
| | - Maria B Carreira
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX 75080, United States.
| | - Christa K McIntyre
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Richardson, TX 75080, United States.
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45
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mRNA Trafficking in the Nervous System: A Key Mechanism of the Involvement of Activity-Regulated Cytoskeleton-Associated Protein (Arc) in Synaptic Plasticity. Neural Plast 2021; 2021:3468795. [PMID: 34603440 PMCID: PMC8486535 DOI: 10.1155/2021/3468795] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/15/2021] [Accepted: 09/07/2021] [Indexed: 12/18/2022] Open
Abstract
Synaptic activity mediates information storage and memory consolidation in the brain and requires a fast de novo synthesis of mRNAs in the nucleus and proteins in synapses. Intracellular localization of a protein can be achieved by mRNA trafficking and localized translation. Activity-regulated cytoskeleton-associated protein (Arc) is a master regulator of synaptic plasticity and plays an important role in controlling large signaling networks implicated in learning, memory consolidation, and behavior. Transcription of the Arc gene may be induced by a short behavioral event, resulting in synaptic activation. Arc mRNA is exported into the cytoplasm and can be trafficked into the dendrite of an activated synapse where it is docked and translated. The structure of Arc is similar to the viral GAG (group-specific antigen) protein, and phylogenic analysis suggests that Arc may originate from the family of Ty3/Gypsy retrotransposons. Therefore, Arc might evolve through “domestication” of retroviruses. Arc can form a capsid-like structure that encapsulates a retrovirus-like sentence in the 3′-UTR (untranslated region) of Arc mRNA. Such complex can be loaded into extracellular vesicles and transported to other neurons or muscle cells carrying not only genetic information but also regulatory signals within neuronal networks. Therefore, Arc mRNA inter- and intramolecular trafficking is essential for the modulation of synaptic activity required for memory consolidation and cognitive functions. Recent studies with single-molecule imaging in live neurons confirmed and extended the role of Arc mRNA trafficking in synaptic plasticity.
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46
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Perez JD, Fusco CM, Schuman EM. A Functional Dissection of the mRNA and Locally Synthesized Protein Population in Neuronal Dendrites and Axons. Annu Rev Genet 2021; 55:183-207. [PMID: 34460296 DOI: 10.1146/annurev-genet-030321-054851] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neurons are characterized by a complex morphology that enables the generation of subcellular compartments with unique biochemical and biophysical properties, such as dendrites, axons, and synapses. To sustain these different compartments and carry a wide array of elaborate operations, neurons express a diverse repertoire of gene products. Extensive regulation at both the messenger RNA (mRNA) and protein levels allows for the differentiation of subcellular compartments as well as numerous forms of plasticity in response to variable stimuli. Among the multiple mechanisms that control cellular functions, mRNA translation is manipulated by neurons to regulate where and when a protein emerges. Interestingly, transcriptomic and translatomic profiles of both dendrites and axons have revealed that the mRNA population only partially predicts the local protein population and that this relation significantly varies between different gene groups. Here, we describe the space that local translation occupies within the large molecular and regulatory complexity of neurons, in contrast to other modes of regulation. We then discuss the specialized organization of mRNAs within different neuronal compartments, as revealed by profiles of the local transcriptome. Finally, we discuss the features and functional implications of both locally correlated-and anticorrelated-mRNA-protein relations both under baseline conditions and during synaptic plasticity. Expected final online publication date for the Annual Review of Genetics, Volume 55 is November 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Julio D Perez
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany;
| | - Claudia M Fusco
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany;
| | - Erin M Schuman
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany;
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47
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Parent MB, Ferreira-Neto HC, Kruemmel AR, Althammer F, Patel AA, Keo S, Whitley KE, Cox DN, Stern JE. Heart failure impairs mood and memory in male rats and down-regulates the expression of numerous genes important for synaptic plasticity in related brain regions. Behav Brain Res 2021; 414:113452. [PMID: 34274373 DOI: 10.1016/j.bbr.2021.113452] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 05/21/2021] [Accepted: 07/08/2021] [Indexed: 12/01/2022]
Abstract
Chronic heart failure (HF) is a serious disorder that afflicts more than 26 million patients worldwide. HF is comorbid with depression, anxiety and memory deficits that have serious implications for quality of life and self-care in patients who have HF. Still, there are few studies that have assessed the effects of severely reduced ejection fraction (≤40 %) on cognition in non-human animal models. Moreover, limited information is available regarding the effects of HF on genetic markers of synaptic plasticity in brain areas critical for memory and mood regulation. We induced HF in male rats and tested mood and anxiety (sucrose preference and elevated plus maze) and memory (spontaneous alternation and inhibitory avoidance) and measured the simultaneous expression of 84 synaptic plasticity-associated genes in dorsal (DH) and ventral hippocampus (VH), basolateral (BLA) and central amygdala (CeA) and prefrontal cortex (PFC). We also included the hypothalamic paraventricular nucleus (PVN), which is implicated in neurohumoral activation in HF. Our results show that rats with severely reduced ejection fraction recapitulate behavioral symptoms seen in patients with chronic HF including, increased anxiety and impaired memory in both tasks. HF also downregulated several synaptic-plasticity genes in PFC and PVN, moderate decreases in DH and CeA and minimal effects in BLA and VH. Collectively, these findings identify candidate brain areas and molecular mechanisms underlying HF-induced disturbances in mood and memory.
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Affiliation(s)
- Marise B Parent
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | | | | | | | - Atit A Patel
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | - Sreinick Keo
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | | | - Daniel N Cox
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | - Javier E Stern
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA.
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48
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Hallin EI, Bramham CR, Kursula P. Structural properties and peptide ligand binding of the capsid homology domains of human Arc. Biochem Biophys Rep 2021; 26:100975. [PMID: 33732907 PMCID: PMC7941041 DOI: 10.1016/j.bbrep.2021.100975] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/18/2021] [Accepted: 02/22/2021] [Indexed: 12/14/2022] Open
Abstract
The activity-regulated cytoskeleton-associated protein (Arc) is important for synaptic plasticity and the normal function of the brain. Arc interacts with neuronal postsynaptic proteins, but the mechanistic details of its function have not been fully established. The C-terminal domain of Arc consists of tandem domains, termed the N- and C-lobe. The N-lobe harbours a peptide binding site, able to bind multiple targets. By measuring the affinity of human Arc towards various peptides from stargazin and guanylate kinase-associated protein (GKAP), we have refined its specificity determinants. We found two sites in the GKAP repeat region that bind to Arc and confirmed these interactions by X-ray crystallography. Phosphorylation of the stargazin peptide did not affect binding affinity but caused changes in thermodynamic parameters. Comparison of the crystal structures of three high-resolution human Arc-peptide complexes identifies three conserved C-H…π interactions at the binding cavity, explaining the sequence specificity of short linear motif binding by Arc. We further characterise central residues of the Arc lobe fold, show the effects of peptide binding on protein dynamics, and identify acyl carrier proteins as structures similar to the Arc lobes. We hypothesise that Arc may affect protein-protein interactions and phase separation at the postsynaptic density, affecting protein turnover and re-modelling of the synapse. The present data on Arc structure and ligand binding will help in further deciphering these processes.
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Affiliation(s)
| | | | - Petri Kursula
- Department of Biomedicine, University of Bergen, Norway
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Finland
- Biocenter Oulu, University of Oulu, Finland
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49
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Bin Ibrahim MZ, Benoy A, Sajikumar S. Long-term plasticity in the hippocampus: maintaining within and 'tagging' between synapses. FEBS J 2021; 289:2176-2201. [PMID: 34109726 DOI: 10.1111/febs.16065] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/15/2021] [Accepted: 06/01/2021] [Indexed: 12/11/2022]
Abstract
Synapses between neurons are malleable biochemical structures, strengthening and diminishing over time dependent on the type of information they receive. This phenomenon known as synaptic plasticity underlies learning and memory, and its different forms, long-term potentiation (LTP) and long-term depression (LTD), perform varied cognitive roles in reinforcement, relearning and associating memories. Moreover, both LTP and LTD can exist in an early transient form (early-LTP/LTD) or a late persistent form (late-LTP/LTD), which are triggered by different induction protocols, and also differ in their dependence on protein synthesis and the involvement of key molecular players. Beyond homosynaptic modifications, synapses can also interact with one another. This is encapsulated in the synaptic tagging and capture hypothesis (STC), where synapses expressing early-LTP/LTD present a 'tag' that can capture the protein synthesis products generated during a temporally proximal late-LTP/LTD induction. This 'tagging' phenomenon forms the framework of synaptic interactions in various conditions and accounts for the cellular basis of the time-dependent associativity of short-lasting and long-lasting memories. All these synaptic modifications take place under controlled neuronal conditions, regulated by subcellular elements such as epigenetic regulation, proteasomal degradation and neuromodulatory signals. Here, we review current understanding of the different forms of synaptic plasticity and its regulatory mechanisms in the hippocampus, a brain region critical for memory formation. We also discuss expression of plasticity in hippocampal CA2 area, a long-overlooked narrow hippocampal subfield and the behavioural correlate of STC. Lastly, we put forth perspectives for an integrated view of memory representation in synapses.
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Affiliation(s)
- Mohammad Zaki Bin Ibrahim
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Life Sciences Institute Neurobiology Programme, National University of Singapore, Singapore
| | - Amrita Benoy
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Life Sciences Institute Neurobiology Programme, National University of Singapore, Singapore
| | - Sreedharan Sajikumar
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Life Sciences Institute Neurobiology Programme, National University of Singapore, Singapore.,Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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50
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Walczyk-Mooradally A, Holborn J, Singh K, Tyler M, Patnaik D, Wesseling H, Brandon NJ, Steen J, Graether SP, Haggarty SJ, Lalonde J. Phosphorylation-dependent control of Activity-regulated cytoskeleton-associated protein (Arc) protein by TNIK. J Neurochem 2021. [PMID: 34077555 DOI: 10.1111/jnc.15077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Activity-regulated cytoskeleton-associated protein (Arc) is an immediate early gene product that support neuroplastic changes important for cognitive function and memory formation. As a protein with homology to the retroviral Gag protein, a particular characteristic of Arc is its capacity to self-assemble into virus-like capsids that can package mRNAs and transfer those transcripts to other cells. Although a lot has been uncovered about the contributions of Arc to neuron biology and behavior, very little is known about how different functions of Arc are coordinately regulated both temporally and spatially in neurons. The answer to this question we hypothesized must involve the occurrence of different protein post-translational modifications acting to confer specificity. In this study, we used mass spectrometry and sequence prediction strategies to map novel Arc phosphorylation sites. Our approach led us to recognize serine 67 (S67) and threonine 278 (T278) as residues that can be modified by TNIK, which is a kinase abundantly expressed in neurons that shares many functional overlaps with Arc and has, along with its interacting proteins such as the NMDA receptor, and been implicated as a risk factor for psychiatric disorders. Furthermore, characterization of each residue using site-directed mutagenesis to create S67 and T278 mutant variants revealed that TNIK action at those amino acids can strongly influence Arc's subcellular distribution and self-assembly as capsids. Together, our findings reveal an unsuspected connection between Arc and TNIK. Better understanding of the interplay between these two proteins in neuronal cells could lead to new insights about apparition and progression of psychiatric disorders. Cover Image for this issue: https://doi.org/10.1111/jnc.15077.
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Affiliation(s)
| | - Jennifer Holborn
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Karamjeet Singh
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Marshall Tyler
- Massachusetts General Hospital, Centre for Genomic Medicine, Boston, MA, USA
| | - Debasis Patnaik
- Massachusetts General Hospital, Centre for Genomic Medicine, Boston, MA, USA
| | - Hendrik Wesseling
- Boston Children's Hospital, F.M. Kirby Center for Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Nicholas J Brandon
- Neuroscience, BioPharmaceuticals R&D, AstraZeneca Boston, Waltham, MA, USA
| | - Judith Steen
- Boston Children's Hospital, F.M. Kirby Center for Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Steffen P Graether
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Stephen J Haggarty
- Massachusetts General Hospital, Centre for Genomic Medicine, Boston, MA, USA
| | - Jasmin Lalonde
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
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