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Abstract
Discovery and development of new medicines requires the talent and passion of both academic and industrial scientists. Identifying the optimal set of circumstances for direct collaboration between academic and industry teams requires a mutual understanding of what each partner brings to the relationship, and an appreciation of the specialized capabilities and scope of work to be undertaken by each group. We provide our perspective on the who, what, where, why, and how for establishing therapeutic and translational research collaborations between academic and industry scientists.
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Wall MJ, Collins DR, Chery SL, Allen ZD, Pastuzyn ED, George AJ, Nikolova VD, Moy SS, Philpot BD, Shepherd JD, Müller J, Ehlers MD, Mabb AM, Corrêa SAL. The Temporal Dynamics of Arc Expression Regulate Cognitive Flexibility. Neuron 2018; 98:1124-1132.e7. [PMID: 29861284 PMCID: PMC6030446 DOI: 10.1016/j.neuron.2018.05.012] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 04/06/2018] [Accepted: 05/04/2018] [Indexed: 10/29/2022]
Abstract
Neuronal activity regulates the transcription and translation of the immediate-early gene Arc/Arg3.1, a key mediator of synaptic plasticity. Proteasome-dependent degradation of Arc tightly limits its temporal expression, yet the significance of this regulation remains unknown. We disrupted the temporal control of Arc degradation by creating an Arc knockin mouse (ArcKR) where the predominant Arc ubiquitination sites were mutated. ArcKR mice had intact spatial learning but showed specific deficits in selecting an optimal strategy during reversal learning. This cognitive inflexibility was coupled to changes in Arc mRNA and protein expression resulting in a reduced threshold to induce mGluR-LTD and enhanced mGluR-LTD amplitude. These findings show that the abnormal persistence of Arc protein limits the dynamic range of Arc signaling pathways specifically during reversal learning. Our work illuminates how the precise temporal control of activity-dependent molecules, such as Arc, regulates synaptic plasticity and is crucial for cognition.
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Affiliation(s)
- Mark J Wall
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Dawn R Collins
- Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK
| | - Samantha L Chery
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA
| | - Zachary D Allen
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA
| | - Elissa D Pastuzyn
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Arlene J George
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA
| | - Viktoriya D Nikolova
- Department of Psychiatry and the Carolina Institute for Developmental Disorders, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Sheryl S Moy
- Department of Psychiatry and the Carolina Institute for Developmental Disorders, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Benjamin D Philpot
- Neuroscience Center, Department of Cell Biology & Physiology, and the Carolina Institute for Developmental Disorders, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Jason D Shepherd
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Jürgen Müller
- Bradford School of Pharmacy and Medical Sciences, University of Bradford, Bradford, BD7 1DP, UK
| | | | - Angela M Mabb
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA.
| | - Sonia A L Corrêa
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK; Bradford School of Pharmacy and Medical Sciences, University of Bradford, Bradford, BD7 1DP, UK.
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Chung CG, Kwon MJ, Jeon KH, Hyeon DY, Han MH, Park JH, Cha IJ, Cho JH, Kim K, Rho S, Kim GR, Jeong H, Lee JW, Kim T, Kim K, Kim KP, Ehlers MD, Hwang D, Lee SB. Golgi Outpost Synthesis Impaired by Toxic Polyglutamine Proteins Contributes to Dendritic Pathology in Neurons. Cell Rep 2018; 20:356-369. [PMID: 28700938 DOI: 10.1016/j.celrep.2017.06.059] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 04/28/2017] [Accepted: 06/21/2017] [Indexed: 11/29/2022] Open
Abstract
Dendrite aberration is a common feature of neurodegenerative diseases caused by protein toxicity, but the underlying mechanisms remain largely elusive. Here, we show that nuclear polyglutamine (polyQ) toxicity resulted in defective terminal dendrite elongation accompanied by a loss of Golgi outposts (GOPs) and a decreased supply of plasma membrane (PM) in Drosophila class IV dendritic arborization (da) (C4 da) neurons. mRNA sequencing revealed that genes downregulated by polyQ proteins included many secretory pathway-related genes, including COPII genes regulating GOP synthesis. Transcription factor enrichment analysis identified CREB3L1/CrebA, which regulates COPII gene expression. CrebA overexpression in C4 da neurons restores the dysregulation of COPII genes, GOP synthesis, and PM supply. Chromatin immunoprecipitation (ChIP)-PCR revealed that CrebA expression is regulated by CREB-binding protein (CBP), which is sequestered by polyQ proteins. Furthermore, co-overexpression of CrebA and Rac1 synergistically restores the polyQ-induced dendrite pathology. Collectively, our results suggest that GOPs impaired by polyQ proteins contribute to dendrite pathology through the CBP-CrebA-COPII pathway.
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Affiliation(s)
- Chang Geon Chung
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - Min Jee Kwon
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - Keun Hye Jeon
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea; Department of Family Medicine, Samsung Medical Center, Seoul 06351, Republic of Korea
| | - Do Young Hyeon
- School of Interdisciplinary Bioscience and Bioengineering, POSTECH, Pohang 37673, Republic of Korea
| | - Myeong Hoon Han
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - Jeong Hyang Park
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - In Jun Cha
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - Jae Ho Cho
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - Kunhyung Kim
- Department of New Biology, DGIST, Daegu 42988, Republic of Korea
| | - Sangchul Rho
- Center for Plant Aging Research, Institute for Basic Science, DGIST, Daegu 42988, Republic of Korea
| | - Gyu Ree Kim
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea
| | - Hyobin Jeong
- Center for Plant Aging Research, Institute for Basic Science, DGIST, Daegu 42988, Republic of Korea
| | - Jae Won Lee
- Department of Applied Chemistry, Institute of Natural Science, College of Applied Science, Kyung Hee University, Yongin 17104, Republic of Korea
| | - TaeSoo Kim
- Department of Life Science and the Research Center for Cellular Homeostasis, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Keetae Kim
- Department of New Biology, DGIST, Daegu 42988, Republic of Korea
| | - Kwang Pyo Kim
- Department of Applied Chemistry, Institute of Natural Science, College of Applied Science, Kyung Hee University, Yongin 17104, Republic of Korea
| | | | - Daehee Hwang
- School of Interdisciplinary Bioscience and Bioengineering, POSTECH, Pohang 37673, Republic of Korea; Department of New Biology, DGIST, Daegu 42988, Republic of Korea; Center for Plant Aging Research, Institute for Basic Science, DGIST, Daegu 42988, Republic of Korea.
| | - Sung Bae Lee
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Republic of Korea.
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Ehlers MD. Neuroscience is the Next Oncology. Innov Clin Neurosci 2018; 15:15-16. [PMID: 29707421 PMCID: PMC5906084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
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Ehlers MD. Peripheral Activity and Central Substrates of BACE1: Therapeutic Implications for Alzheimer's Disease. Biol Psychiatry 2018; 83:393-394. [PMID: 29420953 DOI: 10.1016/j.biopsych.2017.12.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 12/17/2017] [Indexed: 10/18/2022]
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Gray DL, Allen JA, Mente S, O'Connor RE, DeMarco GJ, Efremov I, Tierney P, Volfson D, Davoren J, Guilmette E, Salafia M, Kozak R, Ehlers MD. Impaired β-arrestin recruitment and reduced desensitization by non-catechol agonists of the D1 dopamine receptor. Nat Commun 2018; 9:674. [PMID: 29445200 PMCID: PMC5813016 DOI: 10.1038/s41467-017-02776-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 12/27/2017] [Indexed: 01/07/2023] Open
Abstract
Selective activation of dopamine D1 receptors (D1Rs) has been pursued for 40 years as a therapeutic strategy for neurologic and psychiatric diseases due to the fundamental role of D1Rs in motor function, reward processing, and cognition. All known D1R-selective agonists are catechols, which are rapidly metabolized and desensitize the D1R after prolonged exposure, reducing agonist response. As such, drug-like selective D1R agonists have remained elusive. Here we report a novel series of selective, potent non-catechol D1R agonists with promising in vivo pharmacokinetic properties. These ligands stimulate adenylyl cyclase signaling and are efficacious in a rodent model of Parkinson's disease after oral administration. They exhibit distinct binding to the D1R orthosteric site and a novel functional profile including minimal receptor desensitization, reduced recruitment of β-arrestin, and sustained in vivo efficacy. These results reveal a novel class of D1 agonists with favorable drug-like properties, and define the molecular basis for catechol-specific recruitment of β-arrestin to D1Rs.
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Affiliation(s)
- David L Gray
- Medicine Design, Pfizer Worldwide Research & Development, Cambridge, MA, 02139, USA.
- Internal Medicine, Pfizer Worldwide Research & Development, Cambridge, MA, 02139, USA.
| | - John A Allen
- Internal Medicine, Pfizer Worldwide Research & Development, Cambridge, MA, 02139, USA
- University of Texas Medical Branch, 301 University Boulevard, Galveston, TX, 77555, USA
| | - Scot Mente
- Medicine Design, Pfizer Worldwide Research & Development, Cambridge, MA, 02139, USA
| | - Rebecca E O'Connor
- Medicine Design, Pfizer Worldwide Research & Development, Groton, CT, 06340, USA
| | - George J DeMarco
- Comparative Medicine, Pfizer Worldwide Research & Development, Cambridge, MA, 02139, USA
| | - Ivan Efremov
- Medicine Design, Pfizer Worldwide Research & Development, Cambridge, MA, 02139, USA
| | - Patrick Tierney
- Internal Medicine, Pfizer Worldwide Research & Development, Cambridge, MA, 02139, USA
| | - Dmitri Volfson
- Internal Medicine, Pfizer Worldwide Research & Development, Cambridge, MA, 02139, USA
| | - Jennifer Davoren
- Medicine Design, Pfizer Worldwide Research & Development, Cambridge, MA, 02139, USA
| | - Edward Guilmette
- Internal Medicine, Pfizer Worldwide Research & Development, Cambridge, MA, 02139, USA
| | - Michelle Salafia
- Medicine Design, Pfizer Worldwide Research & Development, Groton, CT, 06340, USA
| | - Rouba Kozak
- Internal Medicine, Pfizer Worldwide Research & Development, Cambridge, MA, 02139, USA
| | - Michael D Ehlers
- Internal Medicine, Pfizer Worldwide Research & Development, Cambridge, MA, 02139, USA.
- Biogen, Inc., 225 Binney St., Cambridge, 02142, MA, USA.
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Conrad KS, Cheng TW, Ysselstein D, Heybrock S, Hoth LR, Chrunyk BA, Am Ende CW, Krainc D, Schwake M, Saftig P, Liu S, Qiu X, Ehlers MD. Lysosomal integral membrane protein-2 as a phospholipid receptor revealed by biophysical and cellular studies. Nat Commun 2017; 8:1908. [PMID: 29199275 PMCID: PMC5712522 DOI: 10.1038/s41467-017-02044-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 11/03/2017] [Indexed: 12/17/2022] Open
Abstract
Lysosomal integral membrane protein-2 (LIMP-2/SCARB2) contributes to endosomal and lysosomal function. LIMP-2 deficiency is associated with neurological abnormalities and kidney failure and, as an acid glucocerebrosidase receptor, impacts Gaucher and Parkinson's diseases. Here we report a crystal structure of a LIMP-2 luminal domain dimer with bound cholesterol and phosphatidylcholine. Binding of these lipids alters LIMP-2 from functioning as a glucocerebrosidase-binding monomer toward a dimeric state that preferentially binds anionic phosphatidylserine over neutral phosphatidylcholine. In cellular uptake experiments, LIMP-2 facilitates transport of phospholipids into murine fibroblasts, with a strong substrate preference for phosphatidylserine. Taken together, these biophysical and cellular studies define the structural basis and functional importance of a form of LIMP-2 for lipid trafficking. We propose a model whereby switching between monomeric and dimeric forms allows LIMP-2 to engage distinct binding partners, a mechanism that may be shared by SR-BI and CD36, scavenger receptor proteins highly homologous to LIMP-2.
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Affiliation(s)
- Karen S Conrad
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA
| | - Ting-Wen Cheng
- Neuroscience Research Unit, Pfizer Worldwide R&D, 610 Main Street, Cambridge, MA, 02139, USA
| | - Daniel Ysselstein
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Saskia Heybrock
- Biochemical Institute, Christian-Albrechts University Kiel, Olshausenstrasse 40, D-24098, Kiel, Germany
| | - Lise R Hoth
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA
| | - Boris A Chrunyk
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA
| | - Christopher W Am Ende
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA
| | - Dimitri Krainc
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Michael Schwake
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Paul Saftig
- Biochemical Institute, Christian-Albrechts University Kiel, Olshausenstrasse 40, D-24098, Kiel, Germany
| | - Shenping Liu
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA.
| | - Xiayang Qiu
- Medicinal Sciences, Pfizer Worldwide R&D, Eastern Point Road, Groton, CT, 06340, USA.
| | - Michael D Ehlers
- Neuroscience Research Unit, Pfizer Worldwide R&D, 610 Main Street, Cambridge, MA, 02139, USA
- Biogen, 225 Binney St., Cambridge, MA, 02142, USA
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8
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Abstract
The conversion of basic biology into new therapeutics requires scientific activities in both academia and industry. Successful drug discovery projects span disciplines, sectors, and institutions and tightly couple laboratory and clinical experiments. Here, Ehlers describes conceptions and misconceptions about how science is conducted in industry versus academia.
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Arce E, Ehlers MD. The Mind Bending Quest for Cognitive Enhancers. Clin Pharmacol Ther 2016; 101:179-181. [PMID: 27706806 PMCID: PMC5260335 DOI: 10.1002/cpt.524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 09/14/2016] [Accepted: 09/23/2016] [Indexed: 11/17/2022]
Abstract
Adequate cognitive functioning is essential for daily activities. When there is an insult to the brain, cognitive abilities can suffer, which, in turn, produce substantial medical and functional impairment. Advances in neurobiology, circuit neuroscience, and clinical assessment technology are converging in a manner that holds promise for the development of new pharmacological agents for cognitive enhancement in neuropsychiatric disease.
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Affiliation(s)
- E Arce
- Neuroscience Research Unit, Pfizer Inc, Cambridge, Massachusetts, USA
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10
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Abstract
Brain disorders remain one of the defining challenges of modern medicine and among the most poorly served with new therapeutics. Advances in human neurogenetics have begun to shed light on the genomic architecture of complex diseases of mood, cognition, brain development, and neurodegeneration. From genome-wide association studies to rare variants, these findings hold promise for defining the pathogenesis of brain disorders that have resisted simple molecular description. However, the path from genetics to new medicines is far from clear and can take decades, even for the most well-understood genetic disorders. In this review, we define three challenges for the field of neurogenetics that we believe must be addressed to translate human genetics efficiently into new therapeutics for brain disorders.
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Affiliation(s)
- Jens R Wendland
- PharmaTherapeutics Clinical Research, Worldwide Research and Development, Pfizer Inc., Cambridge, Massachusetts
| | - Michael D Ehlers
- Neuroscience Research Unit, Worldwide Research and Development, Pfizer Inc., Cambridge, Massachusetts.
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Hanus C, Ehlers MD. Specialization of biosynthetic membrane trafficking for neuronal form and function. Curr Opin Neurobiol 2016; 39:8-16. [PMID: 27010827 DOI: 10.1016/j.conb.2016.03.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/01/2016] [Accepted: 03/07/2016] [Indexed: 10/24/2022]
Abstract
Neuronal growth and synaptic transmission require the continuous production of adhesion molecules, neurotransmitter receptors, ion-channels, and secreted trophic factors, and thus critically relies on the secretory pathway-the series of intracellular organelles including the endoplasmic reticulum (ER) and the Golgi apparatus (GA), where membrane lipids and proteins are synthesized. Commensurate with the gigantic size of the neuronal membrane and its compartmentalization by thousands of synapses with distinct compositions and activities, the neuronal secretory pathway has evolved to both traffic synaptic components over very long distances, and locally control the composition of specified segments of dendrites. Here we review new insights into the distribution and dynamics of dendritic secretory organelles and their impact on postsynaptic compartments.
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Affiliation(s)
- Cyril Hanus
- Department of Synaptic Plasticity, Max Planck Institute for Brain Research, Frankfurt, Germany.
| | - Michael D Ehlers
- Neuroscience Research Unit, BioTherapeutics, Worldwide Research and Development, Pfizer Inc., Cambridge, MA, USA.
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13
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Wang Q, Amato SP, Rubitski DM, Hayward MM, Kormos BL, Verhoest PR, Xu L, Brandon NJ, Ehlers MD. Identification of Phosphorylation Consensus Sequences and Endogenous Neuronal Substrates of the Psychiatric Risk Kinase TNIK. J Pharmacol Exp Ther 2015; 356:410-23. [PMID: 26645429 DOI: 10.1124/jpet.115.229880] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 12/01/2015] [Indexed: 12/28/2022] Open
Abstract
Traf2- and Nck-interacting kinase (TNIK) is a serine/threonine kinase highly expressed in the brain and enriched in the postsynaptic density of glutamatergic synapses in the mammalian brain. Accumulating genetic evidence and functional data have implicated TNIK as a risk factor for psychiatric disorders. However, the endogenous substrates of TNIK in neurons are unknown. Here, we describe a novel selective small molecule inhibitor of the TNIK kinase family. Using this inhibitor, we report the identification of endogenous neuronal TNIK substrates by immunoprecipitation with a phosphomotif antibody followed by mass spectrometry. Phosphorylation consensus sequences were defined by phosphopeptide sequence analysis. Among the identified substrates were members of the delta-catenin family including p120-catenin, δ-catenin, and armadillo repeat gene deleted in velo-cardio-facial syndrome (ARVCF), each of which is linked to psychiatric or neurologic disorders. Using p120-catenin as a representative substrate, we show TNIK-induced p120-catenin phosphorylation in cells requires intact kinase activity and phosphorylation of TNIK at T181 and T187 in the activation loop. Addition of the small molecule TNIK inhibitor or knocking down TNIK by two shRNAs reduced endogenous p120-catenin phosphorylation in cells. Together, using a TNIK inhibitor and phosphomotif antibody, we identify endogenous substrates of TNIK in neurons, define consensus sequences for TNIK, and suggest signaling pathways by which TNIK influences synaptic development and function linked to psychiatric and neurologic disorders.
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Affiliation(s)
- Qi Wang
- Neuroscience & Pain Research Unit, BioTherapeutics Research and Development, Pfizer Inc. Cambridge, Massachusetts (Q.W., S.P.A., D.M.R., N.J.B., M.D.E.); Center of Chemistry Innovation and Excellence, Pfizer Inc., Groton, Connecticut (M.M.H.); Neuroscience Medicinal Chemistry, Pfizer Inc., Cambridge, Massachusetts (B.L.K., P.R.V.);and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts (L.X.)
| | - Stephen P Amato
- Neuroscience & Pain Research Unit, BioTherapeutics Research and Development, Pfizer Inc. Cambridge, Massachusetts (Q.W., S.P.A., D.M.R., N.J.B., M.D.E.); Center of Chemistry Innovation and Excellence, Pfizer Inc., Groton, Connecticut (M.M.H.); Neuroscience Medicinal Chemistry, Pfizer Inc., Cambridge, Massachusetts (B.L.K., P.R.V.);and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts (L.X.)
| | - David M Rubitski
- Neuroscience & Pain Research Unit, BioTherapeutics Research and Development, Pfizer Inc. Cambridge, Massachusetts (Q.W., S.P.A., D.M.R., N.J.B., M.D.E.); Center of Chemistry Innovation and Excellence, Pfizer Inc., Groton, Connecticut (M.M.H.); Neuroscience Medicinal Chemistry, Pfizer Inc., Cambridge, Massachusetts (B.L.K., P.R.V.);and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts (L.X.)
| | - Matthew M Hayward
- Neuroscience & Pain Research Unit, BioTherapeutics Research and Development, Pfizer Inc. Cambridge, Massachusetts (Q.W., S.P.A., D.M.R., N.J.B., M.D.E.); Center of Chemistry Innovation and Excellence, Pfizer Inc., Groton, Connecticut (M.M.H.); Neuroscience Medicinal Chemistry, Pfizer Inc., Cambridge, Massachusetts (B.L.K., P.R.V.);and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts (L.X.)
| | - Bethany L Kormos
- Neuroscience & Pain Research Unit, BioTherapeutics Research and Development, Pfizer Inc. Cambridge, Massachusetts (Q.W., S.P.A., D.M.R., N.J.B., M.D.E.); Center of Chemistry Innovation and Excellence, Pfizer Inc., Groton, Connecticut (M.M.H.); Neuroscience Medicinal Chemistry, Pfizer Inc., Cambridge, Massachusetts (B.L.K., P.R.V.);and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts (L.X.)
| | - Patrick R Verhoest
- Neuroscience & Pain Research Unit, BioTherapeutics Research and Development, Pfizer Inc. Cambridge, Massachusetts (Q.W., S.P.A., D.M.R., N.J.B., M.D.E.); Center of Chemistry Innovation and Excellence, Pfizer Inc., Groton, Connecticut (M.M.H.); Neuroscience Medicinal Chemistry, Pfizer Inc., Cambridge, Massachusetts (B.L.K., P.R.V.);and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts (L.X.)
| | - Lan Xu
- Neuroscience & Pain Research Unit, BioTherapeutics Research and Development, Pfizer Inc. Cambridge, Massachusetts (Q.W., S.P.A., D.M.R., N.J.B., M.D.E.); Center of Chemistry Innovation and Excellence, Pfizer Inc., Groton, Connecticut (M.M.H.); Neuroscience Medicinal Chemistry, Pfizer Inc., Cambridge, Massachusetts (B.L.K., P.R.V.);and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts (L.X.)
| | - Nicholas J Brandon
- Neuroscience & Pain Research Unit, BioTherapeutics Research and Development, Pfizer Inc. Cambridge, Massachusetts (Q.W., S.P.A., D.M.R., N.J.B., M.D.E.); Center of Chemistry Innovation and Excellence, Pfizer Inc., Groton, Connecticut (M.M.H.); Neuroscience Medicinal Chemistry, Pfizer Inc., Cambridge, Massachusetts (B.L.K., P.R.V.);and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts (L.X.)
| | - Michael D Ehlers
- Neuroscience & Pain Research Unit, BioTherapeutics Research and Development, Pfizer Inc. Cambridge, Massachusetts (Q.W., S.P.A., D.M.R., N.J.B., M.D.E.); Center of Chemistry Innovation and Excellence, Pfizer Inc., Groton, Connecticut (M.M.H.); Neuroscience Medicinal Chemistry, Pfizer Inc., Cambridge, Massachusetts (B.L.K., P.R.V.);and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts (L.X.)
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14
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Affiliation(s)
- Patricio O'Donnell
- Neuroscience and Pain Research Unit, BioTherapeutics Research and Development, Pfizer Inc, Cambridge, Massachusetts
| | - Michael D Ehlers
- Neuroscience and Pain Research Unit, BioTherapeutics Research and Development, Pfizer Inc, Cambridge, Massachusetts
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15
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Leurent C, Ehlers MD. Digital technologies for cognitive assessment to accelerate drug development in Alzheimer's disease. Clin Pharmacol Ther 2015; 98:475-6. [PMID: 26272508 PMCID: PMC5052022 DOI: 10.1002/cpt.212] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 08/11/2015] [Indexed: 11/15/2022]
Abstract
For many neurological and psychiatric diseases, novel therapeutics have been elusive for decades. By focusing on attention interference in Alzheimer's disease (AD), we provide a future vision on how emerging mobile, computer, and device‐based cognitive tools are converting classically noisy, subjective, data‐poor clinical endpoints associated with neuropsychiatric disease assessment into a richer, scalable, and objective set of measurements. Incorporation of such endpoints into clinical drug trials holds promise for more quickly and efficiently developing new medicines.
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Affiliation(s)
- C Leurent
- Neuroscience & Pain Research Unit, BioTherapeutics, Worldwide Research and Development, Pfizer Inc., Cambridge, Massachusetts, USA
| | - M D Ehlers
- Neuroscience & Pain Research Unit, BioTherapeutics, Worldwide Research and Development, Pfizer Inc., Cambridge, Massachusetts, USA
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16
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Burette AC, Phend KD, Burette S, Lin Q, Liang M, Foltz G, Taylor N, Wang Q, Brandon NJ, Bates B, Ehlers MD, Weinberg RJ. Organization of TNIK in dendritic spines. J Comp Neurol 2015; 523:1913-24. [PMID: 25753355 DOI: 10.1002/cne.23770] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 02/25/2015] [Accepted: 02/26/2015] [Indexed: 01/16/2023]
Abstract
Tumor necrosis factor receptor-associated factor 2 (TRAF2)- and noncatalytic region of tyrosine kinase (NCK)-interacting kinase (TNIK) has been identified as an interactor in the psychiatric risk factor, Disrupted in Schizophrenia 1 (DISC1). As a step toward deciphering its function in the brain, we performed high-resolution light and electron microscopic immunocytochemistry. We demonstrate here that TNIK is expressed in neurons throughout the adult mouse brain. In striatum and cerebral cortex, TNIK concentrates in dendritic spines, especially in the vicinity of the lateral edge of the synapse. Thus, TNIK is highly enriched at a microdomain critical for glutamatergic signaling.
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Affiliation(s)
- Alain C Burette
- Department of Cell Biology & Physiology, University of North Carolina, Chapel Hill, North Carolina, 27599
| | - Kristen D Phend
- Department of Cell Biology & Physiology, University of North Carolina, Chapel Hill, North Carolina, 27599
| | - Susan Burette
- Department of Cell Biology & Physiology, University of North Carolina, Chapel Hill, North Carolina, 27599
| | - Qingcong Lin
- Shenogen Pharma Group, Beijing, People's Republic of China 102206
| | - Musen Liang
- Department of Pharmacokinetics, Dynamics, and Metabolism, Pfizer, Andover, Massachusetts 01810
| | - Gretchen Foltz
- Clinical Research Unit, Pfizer, New Haven, Connecticut 06511
| | - Noël Taylor
- Biomarker and Personalized Medicine Group, Eisai Product Creation Systems, Eisai, Andover, Massachusetts 01810
| | - Qi Wang
- Neuroscience Research Unit, Pfizer, Cambridge, Massachusetts 02139
| | | | - Brian Bates
- Centers for Therapeutic Innovation, Pfizer, Boston, Massachusetts 02115
| | - Michael D Ehlers
- Neuroscience Research Unit, Pfizer, Cambridge, Massachusetts 02139
| | - Richard J Weinberg
- Department of Cell Biology & Physiology, University of North Carolina, Chapel Hill, North Carolina, 27599.,Neuroscience Center, University of North Carolina, Chapel Hill, North Carolina, 27599
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17
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Mabb AM, Je HS, Wall MJ, Robinson CG, Larsen RS, Qiang Y, Corrêa SAL, Ehlers MD. Triad3A regulates synaptic strength by ubiquitination of Arc. Neuron 2014; 82:1299-316. [PMID: 24945773 DOI: 10.1016/j.neuron.2014.05.016] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/02/2014] [Indexed: 12/12/2022]
Abstract
Activity-dependent gene transcription and protein synthesis underlie many forms of learning-related synaptic plasticity. At excitatory glutamatergic synapses, the immediate early gene product Arc/Arg3.1 couples synaptic activity to postsynaptic endocytosis of AMPA-type glutamate receptors. Although the mechanisms for Arc induction have been described, little is known regarding the molecular machinery that terminates Arc function. Here, we demonstrate that the RING domain ubiquitin ligase Triad3A/RNF216 ubiquitinates Arc, resulting in its rapid proteasomal degradation. Triad3A associates with Arc, localizes to clathrin-coated pits, and is associated with endocytic sites in dendrites and spines. In the absence of Triad3A, Arc accumulates, leading to the loss of surface AMPA receptors. Furthermore, loss of Triad3A mimics and occludes Arc-dependent forms of synaptic plasticity. Thus, degradation of Arc by clathrin-localized Triad3A regulates the availability of synaptic AMPA receptors and temporally tunes Arc-mediated plasticity at glutamatergic synapses.
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Affiliation(s)
- Angela M Mabb
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - H Shawn Je
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Signature Research Program in Neuroscience and Behavior Disorders, Duke NUS Graduate Medical School Singapore, 8 College Road, Level 05-29, Singapore 169857, Singapore
| | - Mark J Wall
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Camenzind G Robinson
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Janelia Farm Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Rylan S Larsen
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Yuan Qiang
- Signature Research Program in Neuroscience and Behavior Disorders, Duke NUS Graduate Medical School Singapore, 8 College Road, Level 05-29, Singapore 169857, Singapore
| | - Sonia A L Corrêa
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Michael D Ehlers
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Pfizer Worldwide Research and Development, Neuroscience Research Unit, Cambridge, MA 02139, USA.
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18
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Hanus C, Kochen L, Tom Dieck S, Racine V, Sibarita JB, Schuman EM, Ehlers MD. Synaptic control of secretory trafficking in dendrites. Cell Rep 2014; 7:1771-8. [PMID: 24931613 PMCID: PMC5321479 DOI: 10.1016/j.celrep.2014.05.028] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 03/16/2014] [Accepted: 05/14/2014] [Indexed: 11/24/2022] Open
Abstract
Localized signaling in neuronal dendrites requires tight spatial control of membrane composition. Upon initial synthesis, nascent secretory cargo in dendrites exits the endoplasmic reticulum (ER) from local zones of ER complexity that are spatially coupled to post-ER compartments. Although newly synthesized membrane proteins can be processed locally, the mechanisms that control the spatial range of secretory cargo transport in dendritic segments are unknown. Here, we monitored the dynamics of nascent membrane proteins in dendritic post-ER compartments under regimes of low or increased neuronal activity. In response to activity blockade, post-ER carriers are highly mobile and are transported over long distances. Conversely, increasing synaptic activity dramatically restricts the spatial scale of post-ER trafficking along dendrites. This activity-induced confinement of secretory cargo requires site-specific phosphorylation of the kinesin motor KIF17 by Ca2+/calmodulin-dependent protein kinases (CaMK). Thus, the length scales of early secretory trafficking in dendrites are tuned by activity-dependent regulation of microtubule-dependent transport.
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Affiliation(s)
- Cyril Hanus
- Max Planck Institute for Brain Research, Frankfurt 60438, Germany.
| | - Lisa Kochen
- Max Planck Institute for Brain Research, Frankfurt 60438, Germany
| | | | - Victor Racine
- Institute of Molecular & Cell Biology, Agency for Science, Technology and Research, Singapore 138673, Singapore
| | | | - Erin M Schuman
- Max Planck Institute for Brain Research, Frankfurt 60438, Germany
| | - Michael D Ehlers
- Neuroscience Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA 02139, USA.
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19
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Abstract
Molecular "hitchhiking" through receptor-mediated transcytosis at the blood-brain barrier is a CNS drug delivery strategy. In this issue of Neuron, Niewoehner et al. (2014) describe a modular anti-transferrin receptor Fab approach for shuttling therapeutic antibodies into the brain.
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Affiliation(s)
- Robert D Bell
- Neuroscience Research Unit, Pfizer Worldwide Research and Development, 610 Main Street, Cambridge, MA 02139, USA
| | - Michael D Ehlers
- Neuroscience Research Unit, Pfizer Worldwide Research and Development, 610 Main Street, Cambridge, MA 02139, USA.
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20
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Abstract
Shank family proteins (Shank1, Shank2, and Shank3) are synaptic scaffolding proteins that organize an extensive protein complex at the postsynaptic density (PSD) of excitatory glutamatergic synapses. Recent human genetic studies indicate that SHANK family genes (SHANK1, SHANK2, and SHANK3) are causative genes for idiopathic autism spectrum disorders (ASD). Neurobiological studies of Shank mutations in mice support a general hypothesis of synaptic dysfunction in the pathophysiology of ASD. However, the molecular diversity of SHANK family gene products, as well as the heterogeneity in human and mouse phenotypes, pose challenges to modeling human SHANK mutations. Here, we review the molecular genetics of SHANK mutations in human ASD and discuss recent findings where such mutations have been modeled in mice. Conserved features of synaptic dysfunction and corresponding behaviors in Shank mouse mutants may help dissect the pathophysiology of ASD, but also highlight divergent phenotypes that arise from different mutations in the same gene.
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Affiliation(s)
- Yong-hui Jiang
- Departments of Pediatrics and Neurobiology, Duke University School of Medicine, Durham NC 27710, USA
| | - Michael D. Ehlers
- Pfizer Worldwide Research and Development, Neuroscience Research Unit, Cambridge, MA 02129, USA
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21
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Takatoh J, Nelson A, Zhou X, Bolton MM, Ehlers MD, Arenkiel BR, Mooney R, Wang F. New modules are added to vibrissal premotor circuitry with the emergence of exploratory whisking. Neuron 2013; 77:346-60. [PMID: 23352170 DOI: 10.1016/j.neuron.2012.11.010] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2012] [Indexed: 01/08/2023]
Abstract
Rodents begin to use bilaterally coordinated, rhythmic sweeping of their vibrissae ("whisking") for environmental exploration around 2 weeks after birth. Whether (and how) the vibrissal control circuitry changes after birth is unknown, and the relevant premotor circuitry remains poorly characterized. Using a modified rabies virus transsynaptic tracing strategy, we labeled neurons synapsing directly onto vibrissa facial motor neurons (vFMNs). Sources of potential excitatory, inhibitory, and modulatory vFMN premotor neurons, and differences between the premotor circuitry for vFMNs innervating intrinsic versus extrinsic vibrissal muscles were systematically characterized. The emergence of whisking is accompanied by the addition of new sets of bilateral excitatory inputs to vFMNs from neurons in the lateral paragigantocellularis (LPGi). Furthermore, descending axons from the motor cortex directly innervate LPGi premotor neurons. Thus, neural modules that are well suited to facilitate the bilateral coordination and cortical control of whisking are added to the premotor circuitry in parallel with the emergence of this exploratory behavior.
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Affiliation(s)
- Jun Takatoh
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA
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22
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Peixoto R, Kunz PA, Kwon H, Mabb AM, Sabatini BL, Philpot BD, Ehlers MD. Transsynaptic signaling by activity-dependent cleavage of neuroligin-1. Neuron 2012; 76:396-409. [PMID: 23083741 PMCID: PMC3783515 DOI: 10.1016/j.neuron.2012.07.006] [Citation(s) in RCA: 168] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2012] [Indexed: 12/28/2022]
Abstract
Adhesive contact between pre- and postsynaptic neurons initiates synapse formation during brain development and provides a natural means of transsynaptic signaling. Numerous adhesion molecules and their role during synapse development have been described in detail. However, once established, the mechanisms of adhesive disassembly and its function in regulating synaptic transmission have been unclear. Here, we report that synaptic activity induces acute proteolytic cleavage of neuroligin-1 (NLG1), a postsynaptic adhesion molecule at glutamatergic synapses. NLG1 cleavage is triggered by NMDA receptor activation, requires Ca2+ /calmodulin-dependent protein kinase, and is mediated by proteolytic activity of matrix metalloprotease 9 (MMP9). Cleavage of NLG1 occurs at single activated spines, is regulated by neural activity in vivo, and causes rapid destabilization of its presynaptic partner neurexin-1β (NRX1β). In turn, NLG1 cleavage depresses synaptic transmission by abruptly reducing presynaptic release probability. Thus, local proteolytic control of synaptic adhesion tunes synaptic transmission during brain development and plasticity.
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Affiliation(s)
- Rui Peixoto
- Department of Neurobiology, Duke University Medical Center, Durham NC, USA
- Gulbenkian PhD Program in Biomedicine, Oeiras, Portugal
- Howard Hughes Medical Institute, Department of Neurobiology, Harvard Medical School, Boston MA, USA
| | - Portia A. Kunz
- Department of Cell and Molecular Physiology, Neuroscience Center, Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill NC, USA
| | - Hyungbae Kwon
- Howard Hughes Medical Institute, Department of Neurobiology, Harvard Medical School, Boston MA, USA
| | - Angela M. Mabb
- Department of Cell and Molecular Physiology, Neuroscience Center, Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill NC, USA
| | - Bernardo L. Sabatini
- Howard Hughes Medical Institute, Department of Neurobiology, Harvard Medical School, Boston MA, USA
| | - Benjamin D. Philpot
- Department of Cell and Molecular Physiology, Neuroscience Center, Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill NC, USA
| | - Michael D. Ehlers
- Department of Neurobiology, Duke University Medical Center, Durham NC, USA
- Pfizer Worldwide Research and Development, Neuroscience Research Unit, Cambridge MA, USA
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23
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Güler AD, Rainwater A, Parker JG, Jones GL, Argilli E, Arenkiel BR, Ehlers MD, Bonci A, Zweifel LS, Palmiter RD. Transient activation of specific neurons in mice by selective expression of the capsaicin receptor. Nat Commun 2012; 3:746. [PMID: 22434189 DOI: 10.1038/ncomms1749] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 02/13/2012] [Indexed: 01/30/2023] Open
Abstract
The ability to control the electrical activity of a neuronal subtype is a valuable tool in deciphering the role of discreet cell populations in complex neural circuits. Recent techniques that allow remote control of neurons are either labor intensive and invasive or indirectly coupled to neural electrical potential with low temporal resolution. Here we show the rapid, reversible and direct activation of genetically identified neuronal subpopulations by generating two inducible transgenic mouse models. Confined expression of the capsaicin receptor, TRPV1, allows cell-specific activation after peripheral or oral delivery of ligand in freely moving mice. Capsaicin-induced activation of dopaminergic or serotonergic neurons reversibly alters both physiological and behavioural responses within minutes, and lasts ~10 min. These models showcase a robust and remotely controllable genetic tool that modulates a distinct cell population without the need for invasive and labour-intensive approaches.
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Affiliation(s)
- Ali D Güler
- Howard Hughes Medical Institute and Department of Biochemistry, University of Washington, 1959 NE Pacific Street, Box 357370, Seattle, Washington 98195, USA
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24
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Cui-Wang T, Hanus C, Cui T, Helton T, Bourne J, Watson D, Harris KM, Ehlers MD. Local zones of endoplasmic reticulum complexity confine cargo in neuronal dendrites. Cell 2012; 148:309-21. [PMID: 22265418 DOI: 10.1016/j.cell.2011.11.056] [Citation(s) in RCA: 149] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Revised: 03/28/2011] [Accepted: 11/17/2011] [Indexed: 10/14/2022]
Abstract
Following synthesis, integral membrane proteins dwell in the endoplasmic reticulum (ER) for variable periods that are typically rate limiting for plasma membrane delivery. In neurons, the ER extends for hundreds of microns as an anastomosing network throughout highly branched dendrites. However, little is known about the mobility, spatial scales, or dynamic regulation of cargo in the dendritic ER. Here, we show that membrane proteins, including AMPA-type glutamate receptors, rapidly diffuse within the continuous network of dendritic ER but are confined by increased ER complexity at dendritic branch points and near dendritic spines. The spatial range of receptor mobility is rapidly restricted by type I mGluR signaling through a mechanism involving protein kinase C (PKC) and the ER protein CLIMP63. Moreover, local zones of ER complexity compartmentalize ER export and correspond to sites of new dendritic branches. Thus, local control of ER complexity spatially scales secretory trafficking within elaborate dendritic arbors.
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Affiliation(s)
- Tingting Cui-Wang
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
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25
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Affiliation(s)
- Michael D Ehlers
- Pfizer Worldwide Research and Development, Neuroscience Research Unit, Groton, Connecticut 06340, USA.
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26
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Blanpied TA, Ehlers MD. Membrane trafficking and cytoskeletal dynamics in neuronal function. Mol Cell Neurosci 2012; 48:267-8. [PMID: 22035734 DOI: 10.1016/j.mcn.2011.09.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 09/20/2011] [Accepted: 10/01/2011] [Indexed: 11/29/2022] Open
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27
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Arenkiel BR, Hasegawa H, Yi JJ, Larsen RS, Wallace ML, Philpot BD, Wang F, Ehlers MD. Activity-induced remodeling of olfactory bulb microcircuits revealed by monosynaptic tracing. PLoS One 2011; 6:e29423. [PMID: 22216277 PMCID: PMC3247270 DOI: 10.1371/journal.pone.0029423] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 11/28/2011] [Indexed: 12/21/2022] Open
Abstract
The continued addition of new neurons to mature olfactory circuits represents a remarkable mode of cellular and structural brain plasticity. However, the anatomical configuration of newly established circuits, the types and numbers of neurons that form new synaptic connections, and the effect of sensory experience on synaptic connectivity in the olfactory bulb remain poorly understood. Using in vivo electroporation and monosynaptic tracing, we show that postnatal-born granule cells form synaptic connections with centrifugal inputs and mitral/tufted cells in the mouse olfactory bulb. In addition, newly born granule cells receive extensive input from local inhibitory short axon cells, a poorly understood cell population. The connectivity of short axon cells shows clustered organization, and their synaptic input onto newborn granule cells dramatically and selectively expands with odor stimulation. Our findings suggest that sensory experience promotes the synaptic integration of new neurons into cell type-specific olfactory circuits.
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Affiliation(s)
- Benjamin R. Arenkiel
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas, United States of America
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail: (BRA); (MDE)
| | - Hiroshi Hasegawa
- Department of Cell Biology, Duke University, Durham, North Carolina, United States of America
| | - Jason J. Yi
- Department of Neurobiology, Duke University, Durham, North Carolina, United States of America
| | - Rylan S. Larsen
- Department of Cell and Molecular Physiology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Michael L. Wallace
- Curriculum in Neurobiology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Benjamin D. Philpot
- Department of Cell and Molecular Physiology, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Curriculum in Neurobiology, University of North Carolina, Chapel Hill, North Carolina, United States of America
- UNC Neuroscience Center, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Neurodevelopmental Disorders Research Center, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Fan Wang
- Department of Cell Biology, Duke University, Durham, North Carolina, United States of America
- Department of Neurobiology, Duke University, Durham, North Carolina, United States of America
| | - Michael D. Ehlers
- Department of Cell Biology, Duke University, Durham, North Carolina, United States of America
- Department of Neurobiology, Duke University, Durham, North Carolina, United States of America
- Neuroscience Research Unit, Pfizer Global Research and Development, Groton, Connecticut, United States of America
- * E-mail: (BRA); (MDE)
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28
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Abstract
Odors are initially encoded in the brain as a set of distinct physicochemical characteristics but are ultimately perceived as a unified sensory object--a "smell." It remains unclear how chemical features encoded by diverse odorant receptors and segregated glomeruli in the main olfactory bulb (MOB) are assembled into integrated cortical representations. Combining patterned optical microstimulation of MOB with in vivo electrophysiological recordings in anterior piriform cortex (PCx), we assessed how cortical neurons decode complex activity patterns distributed across MOB glomeruli. PCx firing was insensitive to single-glomerulus photostimulation. Instead, individual cells reported higher-order combinations of coactive glomeruli resembling odor-evoked sensory maps. Intracellular recordings revealed a corresponding circuit architecture providing each cortical neuron with weak synaptic input from a distinct subpopulation of MOB glomeruli. PCx neurons thus detect specific glomerular ensembles, providing an explicit neural representation of chemical feature combinations that are the hallmark of complex odor stimuli.
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Affiliation(s)
- Ian G Davison
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
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29
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Gray SJ, Foti SB, Schwartz JW, Bachaboina L, Taylor-Blake B, Coleman J, Ehlers MD, Zylka MJ, McCown TJ, Samulski RJ. Optimizing promoters for recombinant adeno-associated virus-mediated gene expression in the peripheral and central nervous system using self-complementary vectors. Hum Gene Ther 2011; 22:1143-53. [PMID: 21476867 DOI: 10.1089/hum.2010.245] [Citation(s) in RCA: 248] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
With the increased use of small self-complementary adeno-associated viral (AAV) vectors, the design of compact promoters becomes critical for packaging and expressing larger transgenes under ubiquitous or cell-specific control. In a comparative study of commonly used 800-bp cytomegalovirus (CMV) and chicken β-actin (CBA) promoters, we report significant differences in the patterns of cell-specific gene expression in the central and peripheral nervous systems. The CMV promoter provides high initial neural expression that diminishes over time. The CBA promoter displayed mostly ubiquitous and high neural expression, but substantially lower expression in motor neurons (MNs). We report the creation of a novel hybrid form of the CBA promoter (CBh) that provides robust long-term expression in all cells observed with CMV or CBA, including MNs. To develop a short neuronal promoter to package larger transgenes into AAV vectors, we also found that a 229-bp fragment of the mouse methyl-CpG-binding protein-2 (MeCP2) promoter was able to drive neuron-specific expression within the CNS. Thus the 800-bp CBh promoter provides strong, long-term, and ubiquitous CNS expression whereas the MeCP2 promoter allows an extra 570-bp packaging capacity, with low and mostly neuronal expression within the CNS, similar to the MeCP2 transcription factor.
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Affiliation(s)
- Steven J Gray
- Gene Therapy Center, University of North Carolina, Chapel Hill, NC 27599, USA
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30
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Abstract
Dendritic exocytosis is required for a broad array of neuronal functions including retrograde signaling, neurotransmitter release, synaptic plasticity, and establishment of neuronal morphology. While the details of synaptic vesicle exocytosis from presynaptic terminals have been intensely studied for decades, the mechanisms of dendritic exocytosis are only now emerging. Here we review the molecules and mechanisms of dendritic exocytosis and discuss how exocytosis from dendrites influences neuronal function and circuit plasticity.
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Affiliation(s)
- Matthew J Kennedy
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA.
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31
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Wang X, McCoy PA, Rodriguiz RM, Pan Y, Je HS, Roberts AC, Kim CJ, Berrios J, Colvin JS, Bousquet-Moore D, Lorenzo I, Wu G, Weinberg RJ, Ehlers MD, Philpot BD, Beaudet AL, Wetsel WC, Jiang YH. Synaptic dysfunction and abnormal behaviors in mice lacking major isoforms of Shank3. Hum Mol Genet 2011; 20:3093-108. [PMID: 21558424 DOI: 10.1093/hmg/ddr212] [Citation(s) in RCA: 400] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
SHANK3 is a synaptic scaffolding protein enriched in the postsynaptic density (PSD) of excitatory synapses. Small microdeletions and point mutations in SHANK3 have been identified in a small subgroup of individuals with autism spectrum disorder (ASD) and intellectual disability. SHANK3 also plays a key role in the chromosome 22q13.3 microdeletion syndrome (Phelan-McDermid syndrome), which includes ASD and cognitive dysfunction as major clinical features. To evaluate the role of Shank3 in vivo, we disrupted major isoforms of the gene in mice by deleting exons 4-9. Isoform-specific Shank3(e4-9) homozygous mutant mice display abnormal social behaviors, communication patterns, repetitive behaviors and learning and memory. Shank3(e4-9) male mice display more severe impairments than females in motor coordination. Shank3(e4-9) mice have reduced levels of Homer1b/c, GKAP and GluA1 at the PSD, and show attenuated activity-dependent redistribution of GluA1-containing AMPA receptors. Subtle morphological alterations in dendritic spines are also observed. Although synaptic transmission is normal in CA1 hippocampus, long-term potentiation is deficient in Shank3(e4-9) mice. We conclude that loss of major Shank3 species produces biochemical, cellular and morphological changes, leading to behavioral abnormalities in mice that bear similarities to human ASD patients with SHANK3 mutations.
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Affiliation(s)
- Xiaoming Wang
- Department of Pediatrics, Duke University School of Medicine, Durham, NC 27710, USA
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32
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Kennedy MJ, Hughes RM, Peteya LA, Schwartz JW, Ehlers MD, Tucker CL. Rapid blue-light-mediated induction of protein interactions in living cells. Nat Methods 2010; 7:973-5. [PMID: 21037589 PMCID: PMC3059133 DOI: 10.1038/nmeth.1524] [Citation(s) in RCA: 801] [Impact Index Per Article: 57.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 10/01/2010] [Indexed: 11/09/2022]
Abstract
Dimerizers allowing inducible control of protein-protein interactions are powerful tools for manipulating biological processes. Here we describe genetically encoded light-inducible protein interaction modules based on Arabidopsis thaliana cryptochrome 2 and CIB1 that require no exogenous ligands and dimerize on blue light exposure with sub-second time resolution and subcellular spatial resolution. We demonstrate the general utility of this system by inducing protein translocation, transcription, and Cre-mediated DNA recombination using light.
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Affiliation(s)
- Matthew J Kennedy
- Department of Neurobiology, Duke University Medical Center, Durham North Carolina, USA
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33
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Abstract
Neurons are highly specialized cells whose connectivity at synapses subserves rapid information transfer in the brain. Proper information processing, learning, and memory storage in the brain requires continuous remodeling of synaptic networks. Such remodeling includes synapse formation, elimination, synaptic protein turnover, and changes in synaptic transmission. An emergent mechanism for regulating synapse function is posttranslational modification through the ubiquitin pathway at the postsynaptic membrane. Here, we discuss recent findings implicating ubiquitination and protein degradation in postsynaptic function and plasticity. We describe postsynaptic ubiquitination pathways and their role in brain development, neuronal physiology, and brain disorders.
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Affiliation(s)
- Angela M Mabb
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA
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34
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Abstract
Optimal function of neuronal networks requires interplay between rapid forms of Hebbian plasticity and homeostatic mechanisms that adjust the threshold for plasticity, termed metaplasticity. Numerous forms of rapid synapse plasticity have been examined in detail. However, the rules that govern synaptic metaplasticity are much less clear. Here, we demonstrate a local subunit-specific switch in NMDA receptors that alternately primes or prevents potentiation at single synapses. Prolonged suppression of neurotransmitter release enhances NMDA receptor currents, increases the number of functional NMDA receptors containing NR2B, and augments calcium transients at single dendritic spines. This local switch in NMDA receptors requires spontaneous glutamate release but is independent of action potentials. Moreover, single inactivated synapses exhibit a lower induction threshold for both long-term synaptic potentiation and plasticity-induced spine growth. Thus, spontaneous glutamate release adjusts plasticity threshold at single synapses by local regulation of NMDA receptors, providing a novel spatially delimited form of synaptic metaplasticity.
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Affiliation(s)
- Ming-Chia Lee
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
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35
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36
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Yi JJ, Barnes AP, Hand R, Polleux F, Ehlers MD. TGF-beta signaling specifies axons during brain development. Cell 2010; 142:144-57. [PMID: 20603020 DOI: 10.1016/j.cell.2010.06.010] [Citation(s) in RCA: 206] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 01/21/2010] [Accepted: 04/26/2010] [Indexed: 10/19/2022]
Abstract
In the mammalian brain, the specification of a single axon and multiple dendrites occurs early in the differentiation of most neuron types. Numerous intracellular signaling events for axon specification have been described in detail. However, the identity of the extracellular factor(s) that initiate neuronal polarity in vivo is unknown. Here, we report that transforming growth factor beta (TGF-beta) initiates signaling pathways both in vivo and in vitro to fate naive neurites into axons. Neocortical neurons lacking the type II TGF-beta receptor (TbetaR2) fail to initiate axons during development. Exogenous TGF-beta is sufficient to direct the rapid growth and differentiation of an axon, and genetic enhancement of receptor activity promotes the formation of multiple axons. Finally, we show that the bulk of these TGF-beta-dependent events are mediated by site-specific phosphorylation of Par6. These results define an extrinsic cue for neuronal polarity in vivo that patterns neural circuits in the developing brain.
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Affiliation(s)
- Jason J Yi
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
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37
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Shaked NT, Newpher TM, Ehlers MD, Wax A. Parallel on-axis holographic phase microscopy of biological cells and unicellular microorganism dynamics. Appl Opt 2010; 49:2872-8. [PMID: 20490249 DOI: 10.1364/ao.49.002872] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We apply a wide-field quantitative phase microscopy technique based on parallel two-step phase-shifting on-axis interferometry to visualize live biological cells and microorganism dynamics. The parallel on-axis holographic approach is more efficient with camera spatial bandwidth consumption compared to previous off-axis approaches and thus can capture finer sample spatial details, given a limited spatial bandwidth of a specific digital camera. Additionally, due to the parallel acquisition mechanism, the approach is suitable for visualizing rapid dynamic processes, permitting an interferometric acquisition rate equal to the camera frame rate. The method is demonstrated experimentally through phase microscopy of neurons and unicellular microorganisms.
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Affiliation(s)
- Natan T Shaked
- 1Department of Biomedical Engineering, Fitzpatrick Institute for Photonics, Duke University,Durham, North Carolina 27708, USA.
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38
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Kennedy MJ, Davison IG, Robinson CG, Ehlers MD. Syntaxin-4 defines a domain for activity-dependent exocytosis in dendritic spines. Cell 2010; 141:524-35. [PMID: 20434989 DOI: 10.1016/j.cell.2010.02.042] [Citation(s) in RCA: 209] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 12/10/2009] [Accepted: 02/22/2010] [Indexed: 11/16/2022]
Abstract
Changes in postsynaptic membrane composition underlie many forms of learning-related synaptic plasticity in the brain. At excitatory glutamatergic synapses, fusion of intracellular vesicles at or near the postsynaptic plasma membrane is critical for dendritic spine morphology, retrograde synaptic signaling, and long-term synaptic plasticity. Whereas the molecular machinery for exocytosis in presynaptic terminals has been defined in detail, little is known about the location, kinetics, regulation, or molecules involved in postsynaptic exocytosis. Here, we show that an exocytic domain adjacent to the postsynaptic density (PSD) enables fusion of large, AMPA receptor-containing recycling compartments during elevated synaptic activity. Exocytosis occurs at microdomains enriched in the plasma membrane t-SNARE syntaxin 4 (Stx4), and disruption of Stx4 impairs both spine exocytosis and long-term potentiation (LTP) at hippocampal synapses. Thus, Stx4 defines an exocytic zone that directs membrane fusion for postsynaptic plasticity, revealing a novel specialization for local membrane traffic in dendritic spines.
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Affiliation(s)
- Matthew J Kennedy
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
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39
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Abstract
Brain function emerges from the morphologies, spatial organization and patterns of connectivity established between diverse sets of neurons. Historically, the notion that neuronal structure predicts function stemmed from classic histological staining and neuronal tracing methods. Recent advances in molecular genetics and imaging technologies have begun to reveal previously unattainable details about patterns of functional circuit connectivity and the subcellular organization of synapses in the living brain. This sophisticated molecular and genetic 'toolbox', coupled with new methods in optical and electron microscopy, provides an expanding array of techniques for probing neural anatomy and function.
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Affiliation(s)
- Benjamin R. Arenkiel
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Michael D. Ehlers
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
- Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
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40
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Yashiro K, Riday TT, Condon KH, Roberts AC, Bernardo DR, Prakash R, Weinberg RJ, Ehlers MD, Philpot BD. Ube3a is required for experience-dependent maturation of the neocortex. Nat Neurosci 2009; 12:777-83. [PMID: 19430469 PMCID: PMC2741303 DOI: 10.1038/nn.2327] [Citation(s) in RCA: 248] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Accepted: 03/24/2009] [Indexed: 02/06/2023]
Abstract
Experience-dependent maturation of neocortical circuits is required for normal sensory and cognitive abilities, which are distorted in neurodevelopmental disorders. We tested whether experience-dependent neocortical modifications require Ube3a, an E3 ubiquitin ligase whose dysregulation has been implicated in autism and Angelman syndrome. Using visual cortex as a model, we found that experience-dependent maturation of excitatory cortical circuits was severely impaired in Angelman syndrome model mice deficient in Ube3a. This developmental defect was associated with profound impairments in neocortical plasticity. Normal plasticity was preserved under conditions of sensory deprivation, but was rapidly lost by sensory experiences. The loss of neocortical plasticity is reversible, as late-onset visual deprivation restored normal synaptic plasticity. Furthermore, Ube3a-deficient mice lacked ocular dominance plasticity in vivo when challenged with monocular deprivation. We conclude that Ube3a is necessary for maintaining plasticity during experience-dependent neocortical development and suggest that the loss of neocortical plasticity contributes to deficits associated with Angelman syndrome.
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Affiliation(s)
- Koji Yashiro
- Department of Cell and Molecular Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
- K.Y. present address: Urogenix Inc, Durham NC 27713, USA
| | - Thorfinn T. Riday
- Department of Cell and Molecular Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
- Curriculum in Neurobiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Kathryn H. Condon
- Department of Neurobiology Duke University Medical Center, Durham, NC 27710, USA
| | - Adam C. Roberts
- Department of Cell and Molecular Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
- UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA
- Neurodevelopmental Disorders Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Danilo R. Bernardo
- Department of Cell and Molecular Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Rohit Prakash
- Department of Cell and Molecular Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Richard J. Weinberg
- UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA
- Department of Cell and Developmental Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Michael D. Ehlers
- Department of Neurobiology Duke University Medical Center, Durham, NC 27710, USA
- Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Benjamin D. Philpot
- Department of Cell and Molecular Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
- Curriculum in Neurobiology, University of North Carolina, Chapel Hill, NC 27599, USA
- UNC Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599, USA
- Neurodevelopmental Disorders Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
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41
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Newpher TM, Ehlers MD. Spine microdomains for postsynaptic signaling and plasticity. Trends Cell Biol 2009; 19:218-27. [PMID: 19328694 DOI: 10.1016/j.tcb.2009.02.004] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 02/14/2009] [Accepted: 02/20/2009] [Indexed: 10/21/2022]
Abstract
Changes in the molecular composition and signaling properties of excitatory glutamatergic synapses onto dendritic spines mediate learning-related plasticity in the mammalian brain. This molecular adaptation serves as the most celebrated cell biological model for learning and memory. Within their micron-sized dimensions, dendritic spines restrict the diffusion of signaling molecules and spatially confine the activation of signal transduction pathways. Much of this local regulation occurs by spatial compartmentalization of glutamate receptors. Here, we review recently identified cell biological mechanisms regulating glutamate receptor mobility within individual dendritic spines. We discuss the emerging functions of glutamate receptors residing within sub-spine microdomains and propose a model for distinct signaling platforms with specialized functions in synaptic plasticity.
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Affiliation(s)
- Thomas M Newpher
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
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42
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Hoe HS, Fu Z, Makarova A, Lee JY, Lu C, Feng L, Pajoohesh-Ganji A, Matsuoka Y, Hyman BT, Ehlers MD, Vicini S, Pak DTS, Rebeck GW. The effects of amyloid precursor protein on postsynaptic composition and activity. J Biol Chem 2009; 284:8495-506. [PMID: 19164281 PMCID: PMC2659208 DOI: 10.1074/jbc.m900141200] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Indexed: 11/06/2022] Open
Abstract
The amyloid precursor protein (APP) is cleaved to produce the Alzheimer disease-associated peptide Abeta, but the normal functions of uncleaved APP in the brain are unknown. We found that APP was present in the postsynaptic density of central excitatory synapses and coimmunoprecipitated with N-methyl-d-aspartate receptors (NMDARs). The presence of APP in the postsynaptic density was supported by the observation that NMDARs regulated trafficking and processing of APP; overexpression of the NR1 subunit increased surface levels of APP, whereas activation of NMDARs decreased surface APP and promoted production of Abeta. We transfected APP or APP RNA interference into primary neurons and used electrophysiological techniques to explore the effects of APP on postsynaptic function. Reduction of APP decreased (and overexpression of APP increased) NMDAR whole cell current density and peak amplitude of spontaneous miniature excitatory postsynaptic currents. The increase in NMDAR current by APP was due to specific recruitment of additional NR2B-containing receptors. Consistent with these findings, immunohistochemical experiments demonstrated that APP increased the surface levels and decreased internalization of NR2B subunits. These results demonstrate a novel physiological role of postsynaptic APP in enhancing NMDAR function.
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Affiliation(s)
- Hyang-Sook Hoe
- Departments of Neuroscience, Physiology and Biophysics, Pharmacology, and Neurology, Georgetown University Medical Center, Washington, D. C. 20057-1464, USA
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43
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Wang Z, Edwards JG, Riley N, Provance DW, Karcher R, Li XD, Davison IG, Ikebe M, Mercer JA, Kauer JA, Ehlers MD. Myosin Vb mobilizes recycling endosomes and AMPA receptors for postsynaptic plasticity. Cell 2008; 135:535-48. [PMID: 18984164 DOI: 10.1016/j.cell.2008.09.057] [Citation(s) in RCA: 361] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Revised: 07/16/2008] [Accepted: 09/09/2008] [Indexed: 10/21/2022]
Abstract
Learning-related plasticity at excitatory synapses in the mammalian brain requires the trafficking of AMPA receptors and the growth of dendritic spines. However, the mechanisms that couple plasticity stimuli to the trafficking of postsynaptic cargo are poorly understood. Here we demonstrate that myosin Vb (MyoVb), a Ca2+-sensitive motor, conducts spine trafficking during long-term potentiation (LTP) of synaptic strength. Upon activation of NMDA receptors and corresponding Ca2+ influx, MyoVb associates with recycling endosomes (REs), triggering rapid spine recruitment of endosomes and local exocytosis in spines. Disruption of MyoVb or its interaction with the RE adaptor Rab11-FIP2 abolishes LTP-induced exocytosis from REs and prevents both AMPA receptor insertion and spine growth. Furthermore, induction of tight binding of MyoVb to actin using an acute chemical genetic strategy eradicates LTP in hippocampal slices. Thus, Ca2+-activated MyoVb captures and mobilizes REs for AMPA receptor insertion and spine growth, providing a mechanistic link between the induction and expression of postsynaptic plasticity.
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Affiliation(s)
- Zhiping Wang
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA; Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
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44
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Tiruchinapalli DM, Ehlers MD, Keene JD. Activity-dependent expression of RNA binding protein HuD and its association with mRNAs in neurons. RNA Biol 2008; 5:157-68. [PMID: 18769135 DOI: 10.4161/rna.5.3.6782] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The dendritic trafficking of RNA binding proteins (RBPs) is an important posttranscriptional process involved in the regulation of synaptic plasticity. For example, HuD RBP binds to AU-rich elements (AREs) in the 3' untranslated regions (3'UTR) of immediate-early gene (IEG) transcripts, whose protein products directly affect synaptic plasticity. However, the subcellular localization of HuD RBPs and associated mRNAs has not been investigated following neuronal stimulation. Immunofluorescence analysis revealed activity-dependent dendritic localization of HuD RBPs following KCl stimulation in hippocampal neurons, while immunoprecipitation demonstrated the association of HuD RBP with neuronal mRNAs encoding neuritin, Homer1a, GAP-43, Neuroligins, Verge and CAMKIIalpha. Activity-dependent expression of HuD involves activation of NMDAR as NMDA receptor 1 knockout mice (Nr1(neo-/-)) exhibited decreased expression of HuD. Moreover, translational regulation of HuD-associated transcripts was suggested by its co-localization with poly-A-binding protein (PABP) as well as the cap-binding protein (eIF4E). We propose that post-transcriptional regulation of neuronal mRNAs by HuD RBPs mediates protein synthesis-dependent changes in synaptic plasticity.
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Affiliation(s)
- Dhanrajan M Tiruchinapalli
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA
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45
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Abstract
The large size and geometric complexity of neuronal dendrites necessitate specialized mechanisms to both deliver postsynaptic cargo over extended distances and regulate dendritic composition on a submicron scale. Despite the fundamental importance of membrane trafficking in dendrite growth, synapse formation and plasticity, the organelles and cellular rules governing postsynaptic trafficking are only now emerging. Here we review what is currently known about dendritic secretory organelles and their role in the development, maintenance and plasticity of postsynaptic compartments.
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Affiliation(s)
- Cyril Hanus
- Department of Neurobiology, Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
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46
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Abstract
Among diverse factors regulating excitatory synaptic transmission, the abundance of postsynaptic glutamate receptors figures prominently in molecular memory and learning-related synaptic plasticity. To allow for both long-term maintenance of synaptic transmission and acute changes in synaptic strength, the relative rates of glutamate receptor insertion and removal must be tightly regulated. Interactions with scaffolding proteins control the targeting and signaling properties of glutamate receptors within the postsynaptic membrane. In addition, extrasynaptic receptor populations control the equilibrium of receptor exchange at synapses and activate distinct signaling pathways involved in plasticity. Here, we review recent findings that have shaped our current understanding of receptor mobility between synaptic and extrasynaptic compartments at glutamatergic synapses, focusing on AMPA and NMDA receptors. We also examine the cooperative relationship between intracellular trafficking and surface diffusion of glutamate receptors that underlies the expression of learning-related synaptic plasticity.
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Affiliation(s)
- Thomas M. Newpher
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Michael D. Ehlers
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
- Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
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47
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Arenkiel BR, Klein ME, Davison IG, Katz LC, Ehlers MD. Genetic control of neuronal activity in mice conditionally expressing TRPV1. Nat Methods 2008; 5:299-302. [PMID: 18327266 DOI: 10.1038/nmeth.1190] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Accepted: 02/01/2008] [Indexed: 11/09/2022]
Abstract
Here we describe a knock-in mouse model for Cre-loxP-based conditional expression of TRPV1 in central nervous system neurons. Expression of Cre recombinase using biolistics, lentivirus or genetic intercrosses triggered heterologous expression of TRPV1 in a cell-specific manner. Application of the TRPV1 ligand capsaicin induced strong inward currents, triggered action potentials and activated stereotyped behaviors, allowing cell type-specific chemical genetic control of neuronal activity in vitro and in vivo.
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Affiliation(s)
- Benjamin R Arenkiel
- Howard Hughes Medical Institute, Department of Neurobiology, Duke University Medical Center, Box 3209, Durham, North Carolina 27710, USA
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48
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Abstract
Dendrites and axons exhibit different morphologies and patterns of growth. This difference in neuronal structure is controlled by evolutionarily conserved directed trafficking through the secretory pathway.
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Affiliation(s)
- Michael D Ehlers
- Howard Hughes Medical Institute, Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA.
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49
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Lu J, Helton TD, Blanpied TA, Rácz B, Newpher TM, Weinberg RJ, Ehlers MD. Postsynaptic positioning of endocytic zones and AMPA receptor cycling by physical coupling of dynamin-3 to Homer. Neuron 2007; 55:874-89. [PMID: 17880892 PMCID: PMC2597538 DOI: 10.1016/j.neuron.2007.06.041] [Citation(s) in RCA: 212] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Revised: 06/08/2007] [Accepted: 07/31/2007] [Indexed: 02/07/2023]
Abstract
Endocytosis of AMPA receptors and other postsynaptic cargo occurs at endocytic zones (EZs), stably positioned sites of clathrin adjacent to the postsynaptic density (PSD). The tight localization of postsynaptic endocytosis is thought to control spine composition and regulate synaptic transmission. However, the mechanisms that situate the EZ near the PSD and the role of spine endocytosis in synaptic transmission are unknown. Here, we report that a physical link between dynamin-3 and the postsynaptic adaptor Homer positions the EZ near the PSD. Disruption of dynamin-3 or its interaction with Homer uncouples the PSD from the EZ, resulting in synapses lacking postsynaptic clathrin. Loss of the EZ leads to a loss of synaptic AMPA receptors and reduced excitatory synaptic transmission that corresponds with impaired synaptic recycling. Thus, a physical link between the PSD and the EZ ensures localized endocytosis and recycling by recapturing and maintaining a proximate pool of cycling AMPA receptors.
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Affiliation(s)
- Jiuyi Lu
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Thomas D. Helton
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Thomas A. Blanpied
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Bence Rácz
- Department of Cell and Developmental Biology, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA
| | - Thomas M. Newpher
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Richard J. Weinberg
- Department of Cell and Developmental Biology, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA
- Neuroscience Center, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA
| | - Michael D. Ehlers
- Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
- Corresponding Author: Michael D. Ehlers, M.D., Ph.D., Howard Hughes Medical Institute, Department of Neurobiology, Duke University Medical Center, Box 3209, Durham, NC 27710, USA, Tel: (919)684-1828, FAX (919)668-0631, e-mail:
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50
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Abstract
Neurons extend elaborate dendrites studded with spines. Unexpectedly, this cellular sculpting is regulated by the origin recognition complex—the core machinery for initiating DNA replication.
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Affiliation(s)
- Michael D Ehlers
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA.
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