1
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Cai Y, Cui T, Yin P, Paganelli P, Vicini S, Wang T. Dysregulated glial genes in Alzheimer's disease are essential for homeostatic plasticity: Evidence from integrative epigenetic and single cell analyses. Aging Cell 2023; 22:e13989. [PMID: 37712202 PMCID: PMC10652298 DOI: 10.1111/acel.13989] [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: 04/25/2023] [Revised: 08/18/2023] [Accepted: 08/30/2023] [Indexed: 09/16/2023] Open
Abstract
Synaptic homeostatic plasticity is a foundational regulatory mechanism that maintains the stability of synaptic and neural functions within the nervous system. Impairment of homeostatic regulation has been linked to synapse destabilization during the progression of Alzheimer's disease (AD). Recent epigenetic and transcriptomic characterizations of the nervous system have revealed intricate molecular details about the aging brain and the pathogenesis of neurodegenerative diseases. Yet, how abnormal epigenetic and transcriptomic alterations in different cell types in AD affect synaptic homeostatic plasticity remains to be elucidated. Various glial cell types play critical roles in modulating synaptic functions both during the aging process and in the context of AD. Here, we investigated the impact of glial dysregulation of histone acetylation and transcriptome in AD on synaptic homeostatic plasticity, using computational analysis combined with electrophysiological methods in Drosophila. By integrating snRNA-seq and H3K9ac ChIP-seq data from the same AD patient cohort, we pinpointed cell type-specific signature genes that were transcriptionally altered by histone acetylation. We subsequently investigated the role of these glial genes in regulating presynaptic homeostatic potentiation in Drosophila. Remarkably, nine glial-specific genes, which were identified through our computational method as targets of H3K9ac and transcriptional dysregulation, were found to be crucial for the regulation of synaptic homeostatic plasticity in Drosophila. Our genetic evidence connects abnormal glial transcriptomic changes in AD with the impairment of homeostatic plasticity in the nervous system. In summary, our integrative computational and genetic studies highlight specific glial genes as potential key players in the homeostatic imbalance observed in AD.
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Affiliation(s)
- Yimei Cai
- Department of Pharmacology & PhysiologyGeorgetown University Medical CenterWashingtonD.C.USA
| | - Tao Cui
- Department of Pharmacology & PhysiologyGeorgetown University Medical CenterWashingtonD.C.USA
- Interdisciplinary Program in NeuroscienceGeorgetown University Medical CenterWashingtonD.C.USA
| | - Pengqi Yin
- Department of Pharmacology & PhysiologyGeorgetown University Medical CenterWashingtonD.C.USA
- Present address:
Department of Neurology, Shanghai General HospitalShanghai Jiao Tong University School of MedicineShanghaiChina
- Present address:
Department of Neurology, First Affiliated HospitalHarbin Medical UniversityHarbinChina
| | - Paxton Paganelli
- Department of Pharmacology & PhysiologyGeorgetown University Medical CenterWashingtonD.C.USA
| | - Stefano Vicini
- Department of Pharmacology & PhysiologyGeorgetown University Medical CenterWashingtonD.C.USA
- Interdisciplinary Program in NeuroscienceGeorgetown University Medical CenterWashingtonD.C.USA
| | - Tingting Wang
- Department of Pharmacology & PhysiologyGeorgetown University Medical CenterWashingtonD.C.USA
- Interdisciplinary Program in NeuroscienceGeorgetown University Medical CenterWashingtonD.C.USA
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2
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Chipman PH, Fetter RD, Panzera LC, Bergerson SJ, Karmelic D, Yokoyama S, Hoppa MB, Davis GW. NMDAR-dependent presynaptic homeostasis in adult hippocampus: Synapse growth and cross-modal inhibitory plasticity. Neuron 2022; 110:3302-3317.e7. [PMID: 36070750 PMCID: PMC9588671 DOI: 10.1016/j.neuron.2022.08.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/11/2022] [Accepted: 08/10/2022] [Indexed: 11/25/2022]
Abstract
Homeostatic plasticity (HP) encompasses a suite of compensatory physiological processes that counteract neuronal perturbations, enabling brain resilience. Currently, we lack a complete description of the homeostatic processes that operate within the mammalian brain. Here, we demonstrate that acute, partial AMPAR-specific antagonism induces potentiation of presynaptic neurotransmitter release in adult hippocampus, a form of compensatory plasticity that is consistent with the expression of presynaptic homeostatic plasticity (PHP) documented at peripheral synapses. We show that this compensatory plasticity can be induced within minutes, requires postsynaptic NMDARs, and is expressed via correlated increases in dendritic spine volume, active zone area, and docked vesicle number. Further, simultaneous postsynaptic genetic reduction of GluA1, GluA2, and GluA3 in triple heterozygous knockouts induces potentiation of presynaptic release. Finally, induction of compensatory plasticity at excitatory synapses induces a parallel, NMDAR-dependent potentiation of inhibitory transmission, a cross-modal effect consistent with the anti-epileptic activity of AMPAR-specific antagonists used in humans.
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Affiliation(s)
- Peter H Chipman
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94941, USA
| | - Richard D Fetter
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94941, USA
| | - Lauren C Panzera
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Samuel J Bergerson
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Daniel Karmelic
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94941, USA
| | - Sae Yokoyama
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94941, USA
| | - Michael B Hoppa
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Graeme W Davis
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94941, USA.
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3
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Wenner PA, Pekala D. Homeostatic Regulation of Motoneuron Properties in Development. ADVANCES IN NEUROBIOLOGY 2022; 28:87-107. [PMID: 36066822 DOI: 10.1007/978-3-031-07167-6_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Homeostatic plasticity represents a set of compensatory mechanisms that are engaged following a perturbation to some feature of neuronal or network function. Homeostatic mechanisms are most robustly expressed during development, a period that is replete with various perturbations such as increased cell size and the addition/removal of synaptic connections. In this review we look at numerous studies that have advanced our understanding of homeostatic plasticity by taking advantage of the accessibility of developing motoneurons. We discuss the homeostatic regulation of embryonic movements in the living chick embryo and describe the spinal compensatory mechanisms that act to recover these movements (homeostatic intrinsic plasticity) or stabilize synaptic strength (synaptic scaling). We describe the expression and triggering mechanisms of these forms of homeostatic plasticity and thereby gain an understanding of their roles in the motor system. We then illustrate how these findings can be extended to studies of developing motoneurons in other systems including the rodents, zebrafish, and fly. Furthermore, studies in developing drosophila have been critical in identifying some of the molecular signaling cascades and expression mechanisms that underlie homeostatic intrinsic membrane excitability. This powerful model organism has also been used to study a presynaptic form of homeostatic plasticity where increases or decreases in synaptic transmission are associated with compensatory changes in probability of release at the neuromuscular junction. Further, we describe studies that demonstrate homeostatic adjustments of ion channel expression following perturbations to other kinds of ion channels. Finally, we discuss work in xenopus that shows a homeostatic regulation of neurotransmitter phenotype in developing motoneurons following activity perturbations. Together, this work illustrates the importance of developing motoneurons in elucidating the mechanisms and roles of homeostatic plasticity.
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Affiliation(s)
- Peter A Wenner
- Department of Cell Biology, Whitehead Biomedical Research Building, Emory University School of Medicine, Atlanta, GA, USA.
| | - Dobromila Pekala
- Department of Cell Biology, Whitehead Biomedical Research Building, Emory University School of Medicine, Atlanta, GA, USA
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4
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Nair AG, Muttathukunnel P, Müller M. Distinct molecular pathways govern presynaptic homeostatic plasticity. Cell Rep 2021; 37:110105. [PMID: 34910905 PMCID: PMC8692748 DOI: 10.1016/j.celrep.2021.110105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 10/05/2021] [Accepted: 11/16/2021] [Indexed: 11/30/2022] Open
Abstract
Presynaptic homeostatic plasticity (PHP) stabilizes synaptic transmission by counteracting impaired neurotransmitter receptor function through neurotransmitter release potentiation. PHP is thought to be triggered by impaired receptor function and to involve a stereotypic signaling pathway. However, here we demonstrate that different receptor perturbations that similarly reduce synaptic transmission result in different responses at the Drosophila neuromuscular junction. While receptor inhibition by the glutamate receptor (GluR) antagonist γ-D-glutamylglycine (γDGG) is not compensated by PHP, the GluR inhibitors Philanthotoxin-433 (PhTx) and Gyki-53655 (Gyki) induce compensatory PHP. Intriguingly, PHP triggered by PhTx and Gyki involve separable signaling pathways, including inhibition of distinct GluR subtypes, differential modulation of the active-zone scaffold Bruchpilot, and short-term plasticity. Moreover, while PHP upon Gyki treatment does not require genes promoting PhTx-induced PHP, it involves presynaptic protein kinase D. Thus, synapses not only respond differentially to similar activity impairments, but achieve homeostatic compensation via distinct mechanisms, highlighting the diversity of homeostatic signaling.
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Affiliation(s)
- Anu G Nair
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Department of Neuroscience, Karolinska Institute, 17177 Stockholm, Sweden
| | - Paola Muttathukunnel
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich/ETH Zurich, 8057 Zurich, Switzerland
| | - Martin Müller
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich/ETH Zurich, 8057 Zurich, Switzerland.
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5
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Goel P, Dickman D. Synaptic homeostats: latent plasticity revealed at the Drosophila neuromuscular junction. Cell Mol Life Sci 2021; 78:3159-3179. [PMID: 33449150 PMCID: PMC8044042 DOI: 10.1007/s00018-020-03732-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/19/2020] [Accepted: 12/04/2020] [Indexed: 12/11/2022]
Abstract
Homeostatic signaling systems are fundamental forms of biological regulation that maintain stable functionality in a changing environment. In the nervous system, synapses are crucial substrates for homeostatic modulation, serving to establish, maintain, and modify the balance of excitation and inhibition. Synapses must be sufficiently flexible to enable the plasticity required for learning and memory but also endowed with the stability to last a lifetime. In response to the processes of development, growth, remodeling, aging, and disease that challenge synapses, latent forms of adaptive plasticity become activated to maintain synaptic stability. In recent years, new insights into the homeostatic control of synaptic function have been achieved using the powerful Drosophila neuromuscular junction (NMJ). This review will focus on work over the past 10 years that has illuminated the cellular and molecular mechanisms of five homeostats that operate at the fly NMJ. These homeostats adapt to loss of postsynaptic neurotransmitter receptor functionality, glutamate imbalance, axonal injury, as well as aberrant synaptic growth and target innervation. These diverse homeostats work independently yet can be simultaneously expressed to balance neurotransmission. Growing evidence from this model glutamatergic synapse suggests these ancient homeostatic signaling systems emerged early in evolution and are fundamental forms of plasticity that also function to stabilize mammalian cholinergic NMJs and glutamatergic central synapses.
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Affiliation(s)
- Pragya Goel
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA.
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6
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Genç Ö, An JY, Fetter RD, Kulik Y, Zunino G, Sanders SJ, Davis GW. Homeostatic plasticity fails at the intersection of autism-gene mutations and a novel class of common genetic modifiers. eLife 2020; 9:55775. [PMID: 32609087 PMCID: PMC7394548 DOI: 10.7554/elife.55775] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 06/07/2020] [Indexed: 01/08/2023] Open
Abstract
We identify a set of common phenotypic modifiers that interact with five independent autism gene orthologs (RIMS1, CHD8, CHD2, WDFY3, ASH1L) causing a common failure of presynaptic homeostatic plasticity (PHP) in Drosophila. Heterozygous null mutations in each autism gene are demonstrated to have normal baseline neurotransmission and PHP. However, PHP is sensitized and rendered prone to failure. A subsequent electrophysiology-based genetic screen identifies the first known heterozygous mutations that commonly genetically interact with multiple ASD gene orthologs, causing PHP to fail. Two phenotypic modifiers identified in the screen, PDPK1 and PPP2R5D, are characterized. Finally, transcriptomic, ultrastructural and electrophysiological analyses define one mechanism by which PHP fails; an unexpected, maladaptive up-regulation of CREG, a conserved, neuronally expressed, stress response gene and a novel repressor of PHP. Thus, we define a novel genetic landscape by which diverse, unrelated autism risk genes may converge to commonly affect the robustness of synaptic transmission.
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Affiliation(s)
- Özgür Genç
- Department of Biochemistry and Biophysics Kavli Institute for Fundamental Neuroscience University of California, San Francisco, San Francisco, United States
| | - Joon-Yong An
- Department of Psychiatry UCSF Weill Institute for Neurosciences University of California, San Francisco, San Francisco, United States.,School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul, Republic of Korea
| | - Richard D Fetter
- Department of Biochemistry and Biophysics Kavli Institute for Fundamental Neuroscience University of California, San Francisco, San Francisco, United States
| | - Yelena Kulik
- Department of Biochemistry and Biophysics Kavli Institute for Fundamental Neuroscience University of California, San Francisco, San Francisco, United States
| | - Giulia Zunino
- Department of Biochemistry and Biophysics Kavli Institute for Fundamental Neuroscience University of California, San Francisco, San Francisco, United States
| | - Stephan J Sanders
- Department of Psychiatry UCSF Weill Institute for Neurosciences University of California, San Francisco, San Francisco, United States
| | - Graeme W Davis
- Department of Biochemistry and Biophysics Kavli Institute for Fundamental Neuroscience University of California, San Francisco, San Francisco, United States
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7
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Odierna GL, Kerwin SK, Harris LE, Shin GJE, Lavidis NA, Noakes PG, Millard SS. Dscam2 suppresses synaptic strength through a PI3K-dependent endosomal pathway. J Cell Biol 2020; 219:151621. [PMID: 32259198 PMCID: PMC7265308 DOI: 10.1083/jcb.201909143] [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: 09/24/2019] [Revised: 02/19/2020] [Accepted: 03/05/2020] [Indexed: 11/22/2022] Open
Abstract
Dscam2 is a cell surface protein required for neuronal development in Drosophila; it can promote neural wiring through homophilic recognition that leads to either adhesion or repulsion between neurites. Here, we report that Dscam2 also plays a post-developmental role in suppressing synaptic strength. This function is dependent on one of two distinct extracellular isoforms of the protein and is autonomous to motor neurons. We link the PI3K enhancer, Centaurin gamma 1A, to the Dscam2-dependent regulation of synaptic strength and show that changes in phosphoinositide levels correlate with changes in endosomal compartments that have previously been associated with synaptic strength. Using transmission electron microscopy, we find an increase in synaptic vesicles at Dscam2 mutant active zones, providing a rationale for the increase in synaptic strength. Our study provides the first evidence that Dscam2 can regulate synaptic physiology and highlights how diverse roles of alternative protein isoforms can contribute to unique aspects of brain development and function.
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Affiliation(s)
- G Lorenzo Odierna
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Sarah K Kerwin
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Lucy E Harris
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Grace Ji-Eun Shin
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia.,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY
| | - Nickolas A Lavidis
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Peter G Noakes
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - S Sean Millard
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
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8
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Wang T, Morency DT, Harris N, Davis GW. Epigenetic Signaling in Glia Controls Presynaptic Homeostatic Plasticity. Neuron 2020; 105:491-505.e3. [PMID: 31810838 PMCID: PMC7518042 DOI: 10.1016/j.neuron.2019.10.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 08/30/2019] [Accepted: 10/29/2019] [Indexed: 01/02/2023]
Abstract
Epigenetic gene regulation shapes neuronal fate in the embryonic nervous system. Post-embryonically, epigenetic signaling within neurons has been associated with impaired learning, autism, ataxia, and schizophrenia. Epigenetic factors are also enriched in glial cells. However, little is known about epigenetic signaling in glia and nothing is known about the intersection of glial epigenetic signaling and presynaptic homeostatic plasticity. During a screen for genes involved in presynaptic homeostatic synaptic plasticity, we identified an essential role for the histone acetyltransferase and deubiquitinase SAGA complex in peripheral glia. We present evidence that the SAGA complex is necessary for homeostatic plasticity, demonstrating involvement of four new genes in homeostatic plasticity. This is also evidence that glia participate in presynaptic homeostatic plasticity, invoking previously unexplored intercellular, homeostatic signaling at a tripartite synapse. We show, mechanistically, SAGA signaling regulates the composition of and signaling from the extracellular matrix during homeostatic plasticity.
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Affiliation(s)
- Tingting Wang
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Danielle T Morency
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Nathan Harris
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Graeme W Davis
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA.
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9
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Frank CA, James TD, Müller M. Homeostatic control of Drosophila neuromuscular junction function. Synapse 2019; 74:e22133. [PMID: 31556149 PMCID: PMC6817395 DOI: 10.1002/syn.22133] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/05/2019] [Accepted: 09/19/2019] [Indexed: 02/06/2023]
Abstract
The ability to adapt to changing internal and external conditions is a key feature of biological systems. Homeostasis refers to a regulatory process that stabilizes dynamic systems to counteract perturbations. In the nervous system, homeostatic mechanisms control neuronal excitability, neurotransmitter release, neurotransmitter receptors, and neural circuit function. The neuromuscular junction (NMJ) of Drosophila melanogaster has provided a wealth of molecular information about how synapses implement homeostatic forms of synaptic plasticity, with a focus on the transsynaptic, homeostatic modulation of neurotransmitter release. This review examines some of the recent findings from the Drosophila NMJ and highlights questions the field will ponder in coming years.
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Affiliation(s)
- C Andrew Frank
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.,Interdisciplinary Programs in Neuroscience, Genetics, and Molecular Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Thomas D James
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.,Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, Iowa, USA
| | - Martin Müller
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.,Neuroscience Center Zurich, Zurich, Switzerland
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10
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Bilanges B, Posor Y, Vanhaesebroeck B. PI3K isoforms in cell signalling and vesicle trafficking. Nat Rev Mol Cell Biol 2019; 20:515-534. [PMID: 31110302 DOI: 10.1038/s41580-019-0129-z] [Citation(s) in RCA: 296] [Impact Index Per Article: 59.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PI3Ks are a family of lipid kinases that phosphorylate intracellular inositol lipids to regulate signalling and intracellular vesicular traffic. Mammals have eight isoforms of PI3K, divided into three classes. The class I PI3Ks generate 3-phosphoinositide lipids, which directly activate signal transduction pathways. In addition to being frequently genetically activated in cancer, similar mutations in class I PI3Ks have now also been found in a human non-malignant overgrowth syndrome and a primary immune disorder that predisposes to lymphoma. The class II and class III PI3Ks are regulators of membrane traffic along the endocytic route, in endosomal recycling and autophagy, with an often indirect effect on cell signalling. Here, we summarize current knowledge of the different PI3K classes and isoforms, focusing on recently uncovered biological functions and the mechanisms by which these kinases are activated. Deeper insight into the PI3K isoforms will undoubtedly continue to contribute to a better understanding of fundamental cell biological processes and, ultimately, of human disease.
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Affiliation(s)
- Benoit Bilanges
- UCL Cancer Institute, University College London, London, UK.
| | - York Posor
- UCL Cancer Institute, University College London, London, UK.
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11
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Kikuma K, Li X, Perry S, Li Q, Goel P, Chen C, Kim D, Stavropoulos N, Dickman D. Cul3 and insomniac are required for rapid ubiquitination of postsynaptic targets and retrograde homeostatic signaling. Nat Commun 2019; 10:2998. [PMID: 31278365 PMCID: PMC6611771 DOI: 10.1038/s41467-019-10992-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 06/14/2019] [Indexed: 01/05/2023] Open
Abstract
At the Drosophila neuromuscular junction, inhibition of postsynaptic glutamate receptors activates retrograde signaling that precisely increases presynaptic neurotransmitter release to restore baseline synaptic strength. However, the nature of the underlying postsynaptic induction process remains enigmatic. Here, we design a forward genetic screen to discover factors in the postsynaptic compartment necessary to generate retrograde homeostatic signaling. This approach identified insomniac (inc), a putative adaptor for the Cullin-3 (Cul3) ubiquitin ligase complex, which together with Cul3 is essential for normal sleep regulation. Interestingly, we find that Inc and Cul3 rapidly accumulate at postsynaptic compartments following acute receptor inhibition and are required for a local increase in mono-ubiquitination. Finally, we show that Peflin, a Ca2+-regulated Cul3 co-adaptor, is necessary for homeostatic communication, suggesting a relationship between Ca2+ signaling and control of Cul3/Inc activity in the postsynaptic compartment. Our study suggests that Cul3/Inc-dependent mono-ubiquitination, compartmentalized at postsynaptic densities, gates retrograde signaling and provides an intriguing molecular link between the control of sleep and homeostatic plasticity at synapses. The authors use a forward genetic screen to discover postsynaptic factors required for homeostatic synaptic plasticity at the Drosophila neuromuscular junction. They identify insomniac and the ubiquitin ligase Cul3, genes involved in sleep regulation, to be necessary for retrograde homeostatic signalling at this synapse.
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Affiliation(s)
- Koto Kikuma
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Xiling Li
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Sarah Perry
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Qiuling Li
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY, 10016, USA
| | - Pragya Goel
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Catherine Chen
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Daniel Kim
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Nicholas Stavropoulos
- Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY, 10016, USA
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA.
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12
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James TD, Zwiefelhofer DJ, Frank CA. Maintenance of homeostatic plasticity at the Drosophila neuromuscular synapse requires continuous IP 3-directed signaling. eLife 2019; 8:39643. [PMID: 31180325 PMCID: PMC6557630 DOI: 10.7554/elife.39643] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 05/27/2019] [Indexed: 12/18/2022] Open
Abstract
Synapses and circuits rely on neuroplasticity to adjust output and meet physiological needs. Forms of homeostatic synaptic plasticity impart stability at synapses by countering destabilizing perturbations. The Drosophila melanogaster larval neuromuscular junction (NMJ) is a model synapse with robust expression of homeostatic plasticity. At the NMJ, a homeostatic system detects impaired postsynaptic sensitivity to neurotransmitter and activates a retrograde signal that restores synaptic function by adjusting neurotransmitter release. This process has been separated into temporally distinct phases, induction and maintenance. One prevailing hypothesis is that a shared mechanism governs both phases. Here, we show the two phases are separable. Combining genetics, pharmacology, and electrophysiology, we find that a signaling system consisting of PLCβ, inositol triphosphate (IP3), IP3 receptors, and Ryanodine receptors is required only for the maintenance of homeostatic plasticity. We also find that the NMJ is capable of inducing homeostatic signaling even when its sustained maintenance process is absent. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
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Affiliation(s)
- Thomas D James
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, United States.,Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, United States
| | - Danielle J Zwiefelhofer
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, United States
| | - C Andrew Frank
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, United States.,Interdisciplinary Programs in Neuroscience, Genetics and Molecular Medicine, University of Iowa, Iowa City, United States
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13
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Goel P, Dufour Bergeron D, Böhme MA, Nunnelly L, Lehmann M, Buser C, Walter AM, Sigrist SJ, Dickman D. Homeostatic scaling of active zone scaffolds maintains global synaptic strength. J Cell Biol 2019; 218:1706-1724. [PMID: 30914419 PMCID: PMC6504899 DOI: 10.1083/jcb.201807165] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 12/14/2018] [Accepted: 03/06/2019] [Indexed: 12/23/2022] Open
Abstract
Synaptic terminals grow and retract throughout life, yet synaptic strength is maintained within stable physiological ranges. To study this process, we investigated Drosophila endophilin (endo) mutants. Although active zone (AZ) number is doubled in endo mutants, a compensatory reduction in their size homeostatically adjusts global neurotransmitter output to maintain synaptic strength. We find an inverse adaptation in rab3 mutants. Additional analyses using confocal, STED, and electron microscopy reveal a stoichiometric tuning of AZ scaffolds and nanoarchitecture. Axonal transport of synaptic cargo via the lysosomal kinesin adapter Arl8 regulates AZ abundance to modulate global synaptic output and sustain the homeostatic potentiation of neurotransmission. Finally, we find that this AZ scaling can interface with two independent homeostats, depression and potentiation, to remodel AZ structure and function, demonstrating a robust balancing of separate homeostatic adaptations. Thus, AZs are pliable substrates with elastic and modular nanostructures that can be dynamically sculpted to stabilize and tune both local and global synaptic strength.
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Affiliation(s)
- Pragya Goel
- Department of Neurobiology, University of Southern California, Los Angeles, CA
| | | | - Mathias A Böhme
- Neurocure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
| | - Luke Nunnelly
- Department of Neurobiology, University of Southern California, Los Angeles, CA
| | - Martin Lehmann
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | | | - Alexander M Walter
- Neurocure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
| | | | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, CA
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Delvendahl I, Müller M. Homeostatic plasticity—a presynaptic perspective. Curr Opin Neurobiol 2019; 54:155-162. [DOI: 10.1016/j.conb.2018.10.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 10/04/2018] [Indexed: 01/05/2023]
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15
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Sánchez-Alegría K, Flores-León M, Avila-Muñoz E, Rodríguez-Corona N, Arias C. PI3K Signaling in Neurons: A Central Node for the Control of Multiple Functions. Int J Mol Sci 2018; 19:ijms19123725. [PMID: 30477115 PMCID: PMC6321294 DOI: 10.3390/ijms19123725] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 11/13/2018] [Accepted: 11/15/2018] [Indexed: 12/14/2022] Open
Abstract
Phosphoinositide 3-kinase (PI3K) signaling contributes to a variety of processes, mediating many aspects of cellular function, including nutrient uptake, anabolic reactions, cell growth, proliferation, and survival. Less is known regarding its critical role in neuronal physiology, neuronal metabolism, tissue homeostasis, and the control of gene expression in the central nervous system in healthy and diseased states. The aim of the present work is to review cumulative evidence regarding the participation of PI3K pathways in neuronal function, focusing on their role in neuronal metabolism and transcriptional regulation of genes involved in neuronal maintenance and plasticity or on the expression of pathological hallmarks associated with neurodegeneration.
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Affiliation(s)
- Karina Sánchez-Alegría
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, AP 70-228, 04510 México, DF, Mexico.
| | - Manuel Flores-León
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, AP 70-228, 04510 México, DF, Mexico.
| | - Evangelina Avila-Muñoz
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, AP 70-228, 04510 México, DF, Mexico.
| | - Nelly Rodríguez-Corona
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, AP 70-228, 04510 México, DF, Mexico.
| | - Clorinda Arias
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, AP 70-228, 04510 México, DF, Mexico.
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16
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Ortega JM, Genç Ö, Davis GW. Molecular mechanisms that stabilize short term synaptic plasticity during presynaptic homeostatic plasticity. eLife 2018; 7:40385. [PMID: 30422113 PMCID: PMC6250423 DOI: 10.7554/elife.40385] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 11/12/2018] [Indexed: 11/13/2022] Open
Abstract
Presynaptic homeostatic plasticity (PHP) compensates for impaired postsynaptic neurotransmitter receptor function through a rapid, persistent adjustment of neurotransmitter release, an effect that can exceed 200%. An unexplained property of PHP is the preservation of short-term plasticity (STP), thereby stabilizing activity-dependent synaptic information transfer. We demonstrate that the dramatic potentiation of presynaptic release during PHP is achieved while simultaneously maintaining a constant ratio of primed to super-primed synaptic vesicles, thereby preserving STP. Mechanistically, genetic, biochemical and electrophysiological evidence argue that a constant ratio of primed to super-primed synaptic vesicles is achieved by the concerted action of three proteins: Unc18, Syntaxin1A and RIM. Our data support a model based on the regulated availability of Unc18 at the presynaptic active zone, a process that is restrained by Syntaxin1A and facilitated by RIM. As such, regulated vesicle priming/super-priming enables PHP to stabilize both synaptic gain and the activity-dependent transfer of information at a synapse.
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Affiliation(s)
- Jennifer M Ortega
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California San Francisco, San Francisco, California
| | - Özgür Genç
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California San Francisco, San Francisco, California
| | - Graeme W Davis
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California San Francisco, San Francisco, California
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