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Xiong GJ, Sheng ZH. Presynaptic perspective: Axonal transport defects in neurodevelopmental disorders. J Cell Biol 2024; 223:e202401145. [PMID: 38568173 PMCID: PMC10988239 DOI: 10.1083/jcb.202401145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 04/05/2024] Open
Abstract
Disruption of synapse assembly and maturation leads to a broad spectrum of neurodevelopmental disorders. Presynaptic proteins are largely synthesized in the soma, where they are packaged into precursor vesicles and transported into distal axons to ensure precise assembly and maintenance of presynapses. Due to their morphological features, neurons face challenges in the delivery of presynaptic cargos to nascent boutons. Thus, targeted axonal transport is vital to build functional synapses. A growing number of mutations in genes encoding the transport machinery have been linked to neurodevelopmental disorders. Emerging lines of evidence have started to uncover presynaptic mechanisms underlying axonal transport defects, thus broadening the view of neurodevelopmental disorders beyond postsynaptic mechanisms. In this review, we discuss presynaptic perspectives of neurodevelopmental disorders by focusing on impaired axonal transport and disturbed assembly and maintenance of presynapses. We also discuss potential strategies for restoring axonal transport as an early therapeutic intervention.
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Affiliation(s)
- Gui-Jing Xiong
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Zu-Hang Sheng
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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2
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Kirchner MK, Althammer F, Donaldson KJ, Cox DN, Stern JE. Changes in neuropeptide large dense core vesicle trafficking dynamics contribute to adaptive responses to a systemic homeostatic challenge. iScience 2023; 26:108243. [PMID: 38026155 PMCID: PMC10654599 DOI: 10.1016/j.isci.2023.108243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/28/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Neuropeptides are packed into large dense core vesicles (LDCVs) that are transported from the soma out into their processes. Limited information exists regarding mechanisms regulating LDCV trafficking, particularly during challenges to bodily homeostasis. Addressing this gap, we used 2-photon imaging in an ex vivo preparation to study LDCVs trafficking dynamics in vasopressin (VP) neurons, which traffic and release neuropeptide from their dendrites and axons. We report a dynamic bidirectional trafficking of VP-LDCVs with important differences in speed and directionality between axons and dendrites. Acute, short-lasting stimuli known to alter VP firing activity and axonal/dendritic release caused modest changes in VP-LDCVs trafficking dynamics. Conversely, chronic/sustained systemic osmotic challenges upregulated VP-LDCVs trafficking dynamic, with a larger effect in dendrites. These results support differential regulation of dendritic and axonal LDCV trafficking, and that changes in trafficking dynamics constitute a novel mechanism by which peptidergic neurons can efficiently adapt to conditions of increased hormonal demand.
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Affiliation(s)
- Matthew K. Kirchner
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, GA 30303, USA
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA
| | - Ferdinand Althammer
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, GA 30303, USA
- Institute of Human Genetics, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Kevin J. Donaldson
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA
- Center for Neuromics, Georgia State University, Atlanta, GA 30303, USA
| | - Daniel N. Cox
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA
- Center for Neuromics, Georgia State University, Atlanta, GA 30303, USA
| | - Javier E. Stern
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, GA 30303, USA
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA
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3
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Sharma V, Singh TG, Kaur A, Mannan A, Dhiman S. Brain-Derived Neurotrophic Factor: A Novel Dynamically Regulated Therapeutic Modulator in Neurological Disorders. Neurochem Res 2023; 48:317-339. [PMID: 36308619 DOI: 10.1007/s11064-022-03755-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 09/02/2022] [Accepted: 09/03/2022] [Indexed: 02/04/2023]
Abstract
The growth factor brain-derived neurotrophic factor (BDNF), and its receptor tropomyosin-related kinase receptor type B (TrkB) play an active role in numerous areas of the adult brain, where they regulate the neuronal activity, function, and survival. Upregulation and downregulation of BDNF expression are critical for the physiology of neuronal circuits and functioning in the brain. Loss of BDNF function has been reported in the brains of patients with neurodegenerative or psychiatric disorders. This article reviews the BDNF gene structure, transport, secretion, expression and functions in the brain. This article also implicates BDNF in several brain-related disorders, including Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, major depressive disorder, schizophrenia, epilepsy and bipolar disorder.
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Affiliation(s)
- Veerta Sharma
- Chitkara College of Pharmacy, Chitkara University, 140401, Rajpura, Punjab, India
| | - Thakur Gurjeet Singh
- Chitkara College of Pharmacy, Chitkara University, 140401, Rajpura, Punjab, India.
| | - Amarjot Kaur
- Chitkara College of Pharmacy, Chitkara University, 140401, Rajpura, Punjab, India
| | - Ashi Mannan
- Chitkara College of Pharmacy, Chitkara University, 140401, Rajpura, Punjab, India
| | - Sonia Dhiman
- Chitkara College of Pharmacy, Chitkara University, 140401, Rajpura, Punjab, India
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4
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Varangot A, Lebatard S, Bellemain-Sagnard M, Lebouvier L, Hommet Y, Vivien D. Modulations of the neuronal trafficking of tissue-type plasminogen activator (tPA) influences glutamate release. Cell Death Dis 2023; 14:34. [PMID: 36650132 PMCID: PMC9845363 DOI: 10.1038/s41419-022-05543-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/15/2022] [Accepted: 12/22/2022] [Indexed: 01/19/2023]
Abstract
The discovery of the neuronal expression of the serine protease tissue-type plasminogen activator (tPA) has opened new avenues of research, with important implications in the physiopathology of the central nervous system. For example, the interaction of tPA with synaptic receptors (NMDAR, LRP1, Annexin II, and EGFR) and its role in the maturation of BDNF have been reported to influence synaptic plasticity and neuronal survival. However, the mechanisms regulating the neuronal trafficking of tPA are unknown. Here, using high-resolution live cell imaging and a panel of innovative genetic approaches, we first unmasked the dynamic characteristics of the dendritic and axonal trafficking of tPA-containing vesicles under different paradigms of neuronal activation or inhibition. We then report a constitutive exocytosis of tPA- and VAMP2-positive vesicles, dramatically increased in conditions of neuronal activation, with a pattern which was mainly dendritic and thus post-synaptic. We also observed that the synaptic release of tPA led to an increase of the exocytosis of VGlut1 positive vesicles containing glutamate. Finally, we described alterations of the trafficking and exocytosis of neuronal tPA in cultured cortical neurons prepared from tau-22 transgenic mice (a preclinical model of Alzheimer's disease (AD)). Altogether, these data provide new insights about the neuronal trafficking of tPA, contributing to a better knowledge of the tPA-dependent brain functions and dysfunctions.
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Affiliation(s)
- Alexandre Varangot
- Normandie Univ, UNICAEN, INSERM U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), Cyceron, Institut Blood and Brain @ Caen-Normandie (BB@C), Caen, France
| | - Simon Lebatard
- Normandie Univ, UNICAEN, INSERM U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), Cyceron, Institut Blood and Brain @ Caen-Normandie (BB@C), Caen, France
| | - Mathys Bellemain-Sagnard
- Normandie Univ, UNICAEN, INSERM U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), Cyceron, Institut Blood and Brain @ Caen-Normandie (BB@C), Caen, France
| | - Laurent Lebouvier
- Normandie Univ, UNICAEN, INSERM U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), Cyceron, Institut Blood and Brain @ Caen-Normandie (BB@C), Caen, France
| | - Yannick Hommet
- Normandie Univ, UNICAEN, INSERM U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), Cyceron, Institut Blood and Brain @ Caen-Normandie (BB@C), Caen, France
| | - Denis Vivien
- Normandie Univ, UNICAEN, INSERM U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), Cyceron, Institut Blood and Brain @ Caen-Normandie (BB@C), Caen, France.
- Department of clinical research, Caen-Normandie University Hospital, CHU, Caen, France.
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5
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de Assis GG, Hoffman JR. The BDNF Val66Met Polymorphism is a Relevant, But not Determinant, Risk Factor in the Etiology of Neuropsychiatric Disorders - Current Advances in Human Studies: A Systematic Review. Brain Plast 2022; 8:133-142. [PMID: 36721394 PMCID: PMC9837733 DOI: 10.3233/bpl-210132] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2022] [Indexed: 02/03/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) is the brain's most-produced neurotrophin during the lifespan, essentially involved in multiple mechanisms of nervous system development and function. The production/release of BDNF requires multi-stage processing that appears to be regulated at various stages in which the presence of a polymorphism "Val66Met" can exert a critical influence. Aim To synthesize the knowledge on the BDNF Val66Met polymorphism on intracellular processing and function of BDNF. Methods We performed a systematic review and collected all available studies on the post-translation processes of BDNF, regarding the Val66Met polymorphism. Searches were performed up to 21st March 2021. Results Out of 129 eligible papers, 18 studies addressed or had findings relating to BDNF post-translation processes and were included in this review. Discussion Compilation of experimental findings reveals that the Val66Met polymorphism affects BDNF function by slightly altering the processing, distribution, and regulated release of BDNF. Regarding the critical role of pro-BDNF as a pro-apoptotic factor, such alteration might represent a risk for the development of neuropsychiatric disorders.
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Affiliation(s)
- Gilmara Gomes de Assis
- Laboratory of Endocrinology, Brain Institute, Federal University of Rio Grande do Norte, Brazil,Gdansk University of Physical Education and Sports, Faculty of Physical Education, Gdansk, Poland,Correspondence to: Gilmara Gomes de Assis, Gdansk University of Physical Education and Sports, Faculty of Physical Education, Gdansk, Poland; E-mail: ; ORCID: 0000-0002-7198-3601
| | - Jay R. Hoffman
- Department of Physical Therapy, Ariel University, Ariel, Israel
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6
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Nassal JP, Murphy FH, Toonen RF, Verhage M. Differential axonal trafficking of Neuropeptide Y-, LAMP1-, and RAB7-tagged organelles in vivo. eLife 2022; 11:81721. [PMID: 36459486 PMCID: PMC9718525 DOI: 10.7554/elife.81721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 11/22/2022] [Indexed: 12/04/2022] Open
Abstract
Different organelles traveling through neurons exhibit distinct properties in vitro, but this has not been investigated in the intact mammalian brain. We established simultaneous dual color two-photon microscopy to visualize the trafficking of Neuropeptide Y (NPY)-, LAMP1-, and RAB7-tagged organelles in thalamocortical axons imaged in mouse cortex in vivo. This revealed that LAMP1- and RAB7-tagged organelles move significantly faster than NPY-tagged organelles in both anterograde and retrograde direction. NPY traveled more selectively in anterograde direction than LAMP1 and RAB7. By using a synapse marker and a calcium sensor, we further investigated the transport dynamics of NPY-tagged organelles. We found that these organelles slow down and pause at synapses. In contrast to previous in vitro studies, a significant increase of transport speed was observed after spontaneous activity and elevated calcium levels in vivo as well as electrically stimulated activity in acute brain slices. Together, we show a remarkable diversity in speeds and properties of three axonal organelle marker in vivo that differ from properties previously observed in vitro.
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Affiliation(s)
- Joris P Nassal
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU University Medical CenterAmsterdamNetherlands
| | - Fiona H Murphy
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU University Medical CenterAmsterdamNetherlands
| | - Ruud F Toonen
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU University Medical CenterAmsterdamNetherlands
| | - Matthijs Verhage
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU University Medical CenterAmsterdamNetherlands
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7
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Cross DJ, Huber BR, Silverman MA, Cline MM, Gill TB, Cross CG, Cook DG, Minoshima S. Intranasal Paclitaxel Alters Alzheimer's Disease Phenotypic Features in 3xTg-AD Mice. J Alzheimers Dis 2021; 83:379-394. [PMID: 34308901 DOI: 10.3233/jad-210109] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Microtubule stabilizing drugs, commonly used as anti-cancer therapeutics, have been proposed for treatment of Alzheimer's disease (AD); however, many do not cross the blood-brain barrier. OBJECTIVE This research investigated if paclitaxel (PTX) delivered via the intranasal (IN) route could alter the phenotypic progression of AD in 3xTg-AD mice. METHODS We administered intranasal PTX in 3XTg-AD mice (3xTg-AD n = 15, 10 weeks and n = 10, 44 weeks, PTX: 0.6 mg/kg or 0.9%saline (SAL)) at 2-week intervals. After treatment, 3XTg-AD mice underwent manganese-enhanced magnetic resonance imaging to measure in vivo axonal transport. In a separate 3XTg-AD cohort, PTX-treated mice were tested in a radial water tread maze at 52 weeks of age after four treatments, and at 72 weeks of age, anxiety was assessed by an elevated-plus maze after 14 total treatments. RESULTS PTX increased axonal transport rates in treated 3XTg-AD compared to controls (p≤0.003). Further investigation using an in vitro neuron model of Aβ-induced axonal transport disruption confirmed PTX prevented axonal transport deficits. Confocal microscopy after treatment found fewer phospho-tau containing neurons (5.25±3.8 versus 8.33±2.5, p < 0.04) in the CA1, altered microglia, and reduced reactive astrocytes. PTX improved performance of 3xTg-AD on the water tread maze compared to controls and not significantly different from WT (Day 5, 143.8±43 versus 91.5±77s and Day 12, 138.3±52 versus 107.7±75s for SAL versus PTX). Elevated plus maze revealed that PTX-treated 3xTg-AD mice spent more time exploring open arms (Open arm 129.1±80 versus 20.9±31s for PTX versus SAL, p≤0.05). CONCLUSION Taken collectively, these findings indicate that intranasal-administered microtubule-stabilizing drugs may offer a potential therapeutic option for treating AD.
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Affiliation(s)
- Donna J Cross
- Department of Radiology and Imaging Sciences>, University of Utah, Salt Lake City, UT, USA
| | - Bertrand R Huber
- Boston University Alzheimer's Disease and CTE Center, Boston University School of Medicine, Boston, MA, USA.,Department of Neurology, Boston University School of Medicine, Boston, MA, USA
| | - Michael A Silverman
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada.,Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Marcella M Cline
- The Geriatric Research, Education, and Clinical Center (GRECC), Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA.,Departments of Medicine, Pharmacology, Psychiatry & Behavioral Sciences, University of Washington, Seattle, WA, USA
| | - Trevor B Gill
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - Chloe G Cross
- Department of Radiology and Imaging Sciences>, University of Utah, Salt Lake City, UT, USA
| | - David G Cook
- The Geriatric Research, Education, and Clinical Center (GRECC), Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA.,Departments of Medicine, Pharmacology, Psychiatry & Behavioral Sciences, University of Washington, Seattle, WA, USA
| | - Satoshi Minoshima
- Department of Radiology and Imaging Sciences>, University of Utah, Salt Lake City, UT, USA
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8
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Hummel JJA, Hoogenraad CC. Specific KIF1A-adaptor interactions control selective cargo recognition. J Cell Biol 2021; 220:212488. [PMID: 34287616 PMCID: PMC8298099 DOI: 10.1083/jcb.202105011] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 05/28/2021] [Accepted: 07/01/2021] [Indexed: 02/08/2023] Open
Abstract
Intracellular transport in neurons is driven by molecular motors that carry many different cargos along cytoskeletal tracks in axons and dendrites. Identifying how motors interact with specific types of transport vesicles has been challenging. Here, we use engineered motors and cargo adaptors to systematically investigate the selectivity and regulation of kinesin-3 family member KIF1A–driven transport of dense core vesicles (DCVs), lysosomes, and synaptic vesicles (SVs). We dissect the role of KIF1A domains in motor activity and show that CC1 regulates autoinhibition, CC2 regulates motor dimerization, and CC3 and PH mediate cargo binding. Furthermore, we identify that phosphorylation of KIF1A is critical for binding to vesicles. Cargo specificity is achieved by specific KIF1A adaptors; MADD/Rab3GEP links KIF1A to SVs, and Arf-like GTPase Arl8A mediates interactions with DCVs and lysosomes. We propose a model where motor dimerization, posttranslational modifications, and specific adaptors regulate selective KIF1A cargo trafficking.
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Affiliation(s)
- Jessica J A Hummel
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Casper C Hoogenraad
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands.,Department of Neuroscience, Genentech, Inc., South San Francisco, CA
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9
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Frühbeis C, Kuo-Elsner WP, Müller C, Barth K, Peris L, Tenzer S, Möbius W, Werner HB, Nave KA, Fröhlich D, Krämer-Albers EM. Oligodendrocytes support axonal transport and maintenance via exosome secretion. PLoS Biol 2020; 18:e3000621. [PMID: 33351792 PMCID: PMC7787684 DOI: 10.1371/journal.pbio.3000621] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/06/2021] [Accepted: 12/10/2020] [Indexed: 12/28/2022] Open
Abstract
Neurons extend long axons that require maintenance and are susceptible to degeneration. Long-term integrity of axons depends on intrinsic mechanisms including axonal transport and extrinsic support from adjacent glial cells. The mechanisms of support provided by myelinating oligodendrocytes to underlying axons are only partly understood. Oligodendrocytes release extracellular vesicles (EVs) with properties of exosomes, which upon delivery to neurons improve neuronal viability in vitro. Here, we show that oligodendroglial exosome secretion is impaired in 2 mouse mutants exhibiting secondary axonal degeneration due to oligodendrocyte-specific gene defects. Wild-type oligodendroglial exosomes support neurons by improving the metabolic state and promoting axonal transport in nutrient-deprived neurons. Mutant oligodendrocytes release fewer exosomes, which share a common signature of underrepresented proteins. Notably, mutant exosomes lack the ability to support nutrient-deprived neurons and to promote axonal transport. Together, these findings indicate that glia-to-neuron exosome transfer promotes neuronal long-term maintenance by facilitating axonal transport, providing a novel mechanistic link between myelin diseases and secondary loss of axonal integrity. The long-term integrity of neuronal axons depends on intrinsic mechanisms such as axonal transport and on extrinsic support from adjacent glial cells. This study shows that genetic defects in glia that affect axonal integrity impair the secretion of oligodendrocyte exosomes and their ability to support nutrient-deprived neurons and promote axonal transport.
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Affiliation(s)
- Carsten Frühbeis
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Wen Ping Kuo-Elsner
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University of Mainz, Mainz, Germany
- Focus Program Translational Neuroscience, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Christina Müller
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Kerstin Barth
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Leticia Peris
- Grenoble Institut des Neurosciences, Université Grenoble Alpes, Inserm, U1216, Grenoble, France
| | - Stefan Tenzer
- Institute of Immunology, University Medical Center, Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Hauke B. Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Dominik Fröhlich
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University of Mainz, Mainz, Germany
- Translational Neuroscience Facility and Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Eva-Maria Krämer-Albers
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University of Mainz, Mainz, Germany
- Focus Program Translational Neuroscience, Johannes Gutenberg University of Mainz, Mainz, Germany
- * E-mail:
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10
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SPARCL1 Promotes Excitatory But Not Inhibitory Synapse Formation and Function Independent of Neurexins and Neuroligins. J Neurosci 2020; 40:8088-8102. [PMID: 32973045 DOI: 10.1523/jneurosci.0454-20.2020] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/17/2020] [Accepted: 07/12/2020] [Indexed: 12/17/2022] Open
Abstract
Emerging evidence supports roles for secreted extracellular matrix proteins in boosting synaptogenesis, synaptic transmission, and synaptic plasticity. SPARCL1 (also known as Hevin), a secreted non-neuronal protein, was reported to increase synaptogenesis by simultaneously binding to presynaptic neurexin-1α and to postsynaptic neuroligin-1B, thereby catalyzing formation of trans-synaptic neurexin/neuroligin complexes. However, neurexins and neuroligins do not themselves mediate synaptogenesis, raising the question of how SPARCL1 enhances synapse formation by binding to these molecules. Moreover, it remained unclear whether SPARCL1 acts on all synapses containing neurexins and neuroligins or only on a subset of synapses, and whether it enhances synaptic transmission in addition to boosting synaptogenesis or induces silent synapses. To explore these questions, we examined the synaptic effects of SPARCL1 and their dependence on neurexins and neuroligins. Using mixed neuronal and glial cultures from neonatal mouse cortex of both sexes, we show that SPARCL1 selectively increases excitatory but not inhibitory synapse numbers, enhances excitatory but not inhibitory synaptic transmission, and augments NMDAR-mediated synaptic responses more than AMPAR-mediated synaptic responses. None of these effects were mediated by SPARCL1-binding to neurexins or neuroligins. Neurons from triple neurexin-1/2/3 or from quadruple neuroligin-1/2/3/4 conditional KO mice that lacked all neurexins or all neuroligins were fully responsive to SPARCL1. Together, our results reveal that SPARCL1 selectively boosts excitatory but not inhibitory synaptogenesis and synaptic transmission by a novel mechanism that is independent of neurexins and neuroligins.SIGNIFICANCE STATEMENT Emerging evidence supports roles for extracellular matrix proteins in boosting synapse formation and function. Previous studies demonstrated that SPARCL1, a secreted non-neuronal protein, promotes synapse formation in rodent and human neurons. However, it remained unclear whether SPARCL1 acts on all or on only a subset of synapses, induces functional or largely inactive synapses, and generates synapses by bridging presynaptic neurexins and postsynaptic neuroligins. Here, we report that SPARCL1 selectively induces excitatory synapses, increases their efficacy, and enhances their NMDAR content. Moreover, using rigorous genetic manipulations, we show that SPARCL1 does not require neurexins and neuroligins for its activity. Thus, SPARCL1 selectively boosts excitatory synaptogenesis and synaptic transmission by a novel mechanism that is independent of neurexins and neuroligins.
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11
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Abstract
The intracellular transport system in neurons is specialized to an extraordinary degree, enabling the delivery of critical cargo to sites in axons or dendrites that are far removed from the cell center. Vesicles formed in the cell body are actively transported by kinesin motors along axonal microtubules to presynaptic sites that can be located more than a meter away. Both growth factors and degradative vesicles carrying aged organelles or aggregated proteins take the opposite route, driven by dynein motors. Distance is not the only challenge; precise delivery of cargos to sites of need must also be accomplished. For example, localized delivery of presynaptic components to hundreds of thousands of "en passant" synapses distributed along the length of a single axon in some neuronal subtypes provides a layer of complexity that must be successfully navigated to maintain synaptic transmission. We review recent advances in the field of axonal transport, with a focus on conceptual developments, and highlight our growing quantitative understanding of neuronal trafficking and its role in maintaining the synaptic function that underlies higher cognitive processes such as learning and memory.
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Affiliation(s)
- Pedro Guedes-Dias
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Institute of Neuronal Cell Biology, Technische Universität München, 80802 Munich, Germany
| | - Erika L F Holzbaur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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12
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Bobadilla AC, Garcia-Keller C, Chareunsouk V, Hyde J, Medina Camacho D, Heinsbroek JA, Kalivas PW. Accumbens brain-derived neurotrophic factor (BDNF) transmission inhibits cocaine seeking. Addict Biol 2019; 24:860-873. [PMID: 29890020 DOI: 10.1111/adb.12638] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/27/2018] [Accepted: 05/01/2018] [Indexed: 12/27/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) regulates a variety of physiological processes, and several studies have explored the role of BDNF in addiction-related brain regions like the nucleus accumbens core (NAcore). We sought to understand the rapid effects of endogenous BDNF on cocaine seeking. Rats were trained to self-administer cocaine and extinguished. We then microinjected two inhibitors of BDNF stimulation of tropomyosin receptor kinase B (TrkB), the non-competitive receptor antagonist ANA-12 and TrkB/Fc, a fusion protein that binds BDNF and prevents TrkB stimulation. Blocking TrkB or inactivating BDNF in NAcore potentiated active lever pressing, showing that endogenous BDNF tone was present and supplying inhibitory tone on cue-induced reinstatement. To determine if exogenous BDNF also negatively regulated reinstatement, BDNF was microinjected into NAcore 15 minutes before cue-induced reinstatement. BDNF decreased cocaine seeking through TrkB receptor binding, but had no effect on inactive lever pressing, spontaneous or cocaine-induced locomotion, or on reinstated sucrose seeking. BDNF-infusion potentiated within trial extinction when microinjected in the NAcore during cue- and context + cue induced reinstatement, and the inhibition of lever pressing lasted at least 3 days post injection. Although decreased reinstatement endured for 3 days when BDNF was administered prior to a reinstatement session, when microinjected before an extinction session or in the home cage, BDNF did not alter subsequent cued-reinstatement. Together, these data show that endogenous BDNF acts on TrKB to provide inhibitory tone on reinstated cocaine seeking, and this effect was recapitulated by exogenous BDNF.
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Affiliation(s)
- Ana-Clara Bobadilla
- Department of Neuroscience; Medical University of South Carolina; Charleston SC USA
| | | | - Victoria Chareunsouk
- Department of Neuroscience; Medical University of South Carolina; Charleston SC USA
| | - Jeffrey Hyde
- Department of Neuroscience; Medical University of South Carolina; Charleston SC USA
- Western Washington University; Department of Psychology and Program in Behavioral Neuroscience; Bellingham WA USA
| | | | - Jasper A. Heinsbroek
- Department of Neuroscience; Medical University of South Carolina; Charleston SC USA
| | - Peter W. Kalivas
- Department of Neuroscience; Medical University of South Carolina; Charleston SC USA
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13
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Kuznetsov IA, Kuznetsov AV. Modelling transport and mean age of dense core vesicles in large axonal arbours. Proc Math Phys Eng Sci 2019; 475:20190284. [PMID: 31534430 PMCID: PMC6735487 DOI: 10.1098/rspa.2019.0284] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 07/19/2019] [Indexed: 10/14/2023] Open
Abstract
A model simulating the transport of dense core vesicles (DCVs) in type II axonal terminals of Drosophila motoneurons has been developed. The morphology of type II terminals is characterized by the large number of en passant boutons. The lack of both scaled-up DCV transport and scaled-down DCV capture in boutons results in a less efficient supply of DCVs to distal boutons. Furthermore, the large number of boutons that DCVs pass as they move anterogradely until they reach the most distal bouton may lead to the capture of a majority of DCVs before they turn around in the most distal bouton to move in the retrograde direction. This may lead to a reduced retrograde flux of DCVs and a lack of DCV circulation in type II terminals. The developed model simulates DCV concentrations in boutons, DCV fluxes between the boutons, age density distributions of DCVs and the mean age of DCVs in various boutons. Unlike published experimental observations, our model predicts DCV circulation in type II terminals after these terminals are filled to saturation. This disagreement is likely because experimentally observed terminals were not at steady state, but rather were accumulating DCVs for later release. Our estimates show that the number of DCVs in the transiting state is much smaller than that in the resident state. DCVs travelling in the axon, rather than DCVs transiting in the terminal, may provide a reserve of DCVs for replenishing boutons after a release. The techniques for modelling transport of DCVs developed in our paper can be used to model the transport of other organelles in axons.
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Affiliation(s)
- I. A. Kuznetsov
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - A. V. Kuznetsov
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910, USA
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14
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Liang C, Carrel D, Omelchenko A, Kim H, Patel A, Fanget I, Firestein BL. Cortical Neuron Migration and Dendrite Morphology are Regulated by Carboxypeptidase E. Cereb Cortex 2019; 29:2890-2903. [PMID: 29982499 PMCID: PMC6611459 DOI: 10.1093/cercor/bhy155] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 06/08/2018] [Accepted: 06/12/2018] [Indexed: 12/28/2022] Open
Abstract
Higher brain function relies on proper development of the cerebral cortex, including correct positioning of neurons and dendrite morphology. Disruptions in these processes may result in various neurocognitive disorders. Mutations in the CPE gene, which encodes carboxypeptidase E (CPE), have been linked to depression and intellectual disability. However, it remains unclear whether CPE is involved in early brain development and in turn contributes to the pathophysiology of neurocognitive disorders. Here, we investigate the effects of CPE knockdown on early brain development and explore the functional significance of the interaction between CPE and its binding partner p150Glued. We demonstrate that CPE is required for cortical neuron migration and dendrite arborization. Furthermore, we show that expression of CPE-C10 redistributes p150Glued from the centrosome and that disruption of CPE interaction with p150Glued leads to abnormal neuronal migration and dendrite morphology, suggesting that a complex between CPE and p150Glued is necessary for proper neurodevelopment.
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Affiliation(s)
- Chen Liang
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ, USA
- Molecular Biosciences Graduate Program, Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ, USA
| | - Damien Carrel
- Neurophotonics Laboratory, Université Paris Descartes, Sorbonne Paris Cité, Centre National de la Recherche Scientifique UMR 8250, Paris, France
| | - Anton Omelchenko
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ, USA
- Neuroscience Graduate Program, Rutgers, The State University of New Jersey, 683 Hoes Lane West, USA
| | - Hyuck Kim
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ, USA
| | - Aashini Patel
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ, USA
| | - Isabelle Fanget
- Neurophotonics Laboratory, Université Paris Descartes, Sorbonne Paris Cité, Centre National de la Recherche Scientifique UMR 8250, Paris, France
| | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, 604 Allison Road, Piscataway, NJ, USA
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15
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Gentile F, Scarlino S, Falzone YM, Lunetta C, Tremolizzo L, Quattrini A, Riva N. The Peripheral Nervous System in Amyotrophic Lateral Sclerosis: Opportunities for Translational Research. Front Neurosci 2019; 13:601. [PMID: 31293369 PMCID: PMC6603245 DOI: 10.3389/fnins.2019.00601] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 05/27/2019] [Indexed: 12/11/2022] Open
Abstract
Although amyotrophic lateral sclerosis (ALS) has been considered as a disorder of the motor neuron (MN) cell body, recent evidences show the non-cell-autonomous pathogenic nature of the disease. Axonal degeneration, loss of peripheral axons and destruction of nerve terminals are early events in the disease pathogenic cascade, anticipating MN degeneration, and the onset of clinical symptoms. Therefore, although ALS and peripheral axonal neuropathies should be differentiated in clinical practice, they also share damage to common molecular pathways, including axonal transport, RNA metabolism and proteostasis. Thus, an extensive evaluation of the molecular events occurring in the peripheral nervous system (PNS) could be fundamental to understand the pathogenic mechanisms of ALS, favoring the discovery of potential disease biomarkers, and new therapeutic targets.
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Affiliation(s)
- Francesco Gentile
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology - San Raffaele Scientific Institute, Milan, Italy
| | - Stefania Scarlino
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology - San Raffaele Scientific Institute, Milan, Italy
| | - Yuri Matteo Falzone
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology - San Raffaele Scientific Institute, Milan, Italy.,Department of Neurology, San Raffaele Scientific Institute, Milan, Italy
| | | | - Lucio Tremolizzo
- Neurology Unit, ALS Clinic, San Gerardo Hospital, University of Milano-Bicocca, Monza, Italy
| | - Angelo Quattrini
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology - San Raffaele Scientific Institute, Milan, Italy
| | - Nilo Riva
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology - San Raffaele Scientific Institute, Milan, Italy.,Department of Neurology, San Raffaele Scientific Institute, Milan, Italy
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16
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Interactions of Glutamatergic Neurotransmission and Brain-Derived Neurotrophic Factor in the Regulation of Behaviors after Nicotine Administration. Int J Mol Sci 2019; 20:ijms20122943. [PMID: 31208140 PMCID: PMC6627482 DOI: 10.3390/ijms20122943] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 06/08/2019] [Accepted: 06/14/2019] [Indexed: 01/16/2023] Open
Abstract
Nicotine causes tobacco dependence, which may result in fatal respiratory diseases. The striatum is a key structure of forebrain basal nuclei associated with nicotine dependence. In the striatum, glutamate release is increased when α7 nicotinic acetylcholine receptors expressed in the glutamatergic terminals are exposed to nicotine, and over-stimulates glutamate receptors in gamma amino-butyric acid (GABA)ergic neurons. These receptor over-stimulations in turn potentiate GABAergic outputs to forebrain basal nuclei and contribute to the increase in psychomotor behaviors associated with nicotine dependence. In parallel with glutamate increases, nicotine exposure elevates brain-derived neurotrophic factor (BDNF) release through anterograde and retrograde targeting of the synapses of glutamatergic terminals and GABAergic neurons. This article reviews nicotine-exposure induced elevations of glutamatergic neurotransmission, the bidirectional targeting of BDNF in the striatum, and the potential regulatory role played by BDNF in behavioral responses to nicotine exposure.
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17
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Specific factors in blood from young but not old mice directly promote synapse formation and NMDA-receptor recruitment. Proc Natl Acad Sci U S A 2019; 116:12524-12533. [PMID: 31160442 DOI: 10.1073/pnas.1902672116] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Aging drives a progressive decline in cognition and decreases synapse numbers and synaptic function in the brain, thereby increasing the risk for neurodegenerative disease. Pioneering studies showed that introduction of blood from young mice into aged mice reversed age-associated cognitive impairments and increased synaptic connectivity in brain, suggesting that young blood contains specific factors that remediate age-associated decreases in brain function. However, whether such factors in blood from young animals act directly on neurons to enhance synaptic connectivity, or whether they act by an indirect mechanism remains unknown. Moreover, which factors in young blood mediate cognitive improvements in old mice is incompletely understood. Here, we show that serum extracted from the blood of young but not old mice, when applied to neurons transdifferentiated from human embryonic stem cells, directly increased dendritic arborization, augmented synapse numbers, doubled dendritic spine-like structures, and elevated synaptic N-methyl-d-aspartate (NMDA) receptors, thereby increasing synaptic connectivity. Mass spectrometry revealed that thrombospondin-4 (THBS4) and SPARC-like protein 1 (SPARCL1) were enriched in serum from young mice. Strikingly, recombinant THBS4 and SPARCL1 both increased dendritic arborization and doubled synapse numbers in cultured neurons. In addition, SPARCL1 but not THBS4 tripled NMDA receptor-mediated synaptic responses. Thus, at least two proteins enriched in young blood, THBS4 and SPARCL1, directly act on neurons as synaptogenic factors. These proteins may represent rejuvenation factors that enhance synaptic connectivity by increasing dendritic arborization, synapse formation, and synaptic transmission.
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18
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Arbogast T, Razaz P, Ellegood J, McKinstry SU, Erdin S, Currall B, Aneichyk T, Lerch JP, Qiu LR, Rodriguiz RM, Henkelman RM, Talkowski ME, Wetsel WC, Golzio C, Katsanis N. Kctd13-deficient mice display short-term memory impairment and sex-dependent genetic interactions. Hum Mol Genet 2019; 28:1474-1486. [PMID: 30590535 PMCID: PMC6489413 DOI: 10.1093/hmg/ddy436] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/12/2018] [Accepted: 12/14/2018] [Indexed: 01/31/2023] Open
Abstract
The 16p11.2 BP4-BP5 deletion and duplication syndromes are associated with a complex spectrum of neurodevelopmental phenotypes that includes developmental delay and autism spectrum disorder, with a reciprocal effect on head circumference, brain structure and body mass index. Mouse models of the 16p11.2 copy number variant have recapitulated some of the patient phenotypes, while studies in flies and zebrafish have uncovered several candidate contributory genes within the region, as well as complex genetic interactions. We evaluated one of these loci, KCTD13, by modeling haploinsufficiency and complete knockout in mice. In contrast to the zebrafish model, and in agreement with recent data, we found normal brain structure in heterozygous and homozygous mutants. However, recapitulating previously observed genetic interactions, we discovered sex-specific brain volumetric alterations in double heterozygous Kctd13xMvp and Kctd13xLat mice. Behavioral testing revealed a significant deficit in novel object recognition, novel location recognition and social transmission of food preference in Kctd13 mutants. These phenotypes were concomitant with a reduction in density of mature spines in the hippocampus, but potentially independent of RhoA abundance, which was unperturbed postnatally in our mutants. Furthermore, transcriptome analyses from cortex and hippocampus highlighted the dysregulation of pathways important in neurodevelopment, the most significant of which was synaptic formation. Together, these data suggest that KCTD13 contributes to the neurocognitive aspects of patients with the BP4-BP5 deletion, likely through genetic interactions with other loci.
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Affiliation(s)
- Thomas Arbogast
- Center for Human Disease Modeling and Department of Cell Biology, Duke University, Durham, NC, USA
| | - Parisa Razaz
- Center for Genomic Medicine and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Jacob Ellegood
- Mouse Imaging Center, the Hospital for Sick Children, Toronto, ON, Canada
| | - Spencer U McKinstry
- Center for Human Disease Modeling and Department of Cell Biology, Duke University, Durham, NC, USA
| | - Serkan Erdin
- Center for Genomic Medicine and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Benjamin Currall
- Center for Genomic Medicine and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Tanya Aneichyk
- Center for Genomic Medicine and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Jason P Lerch
- Mouse Imaging Center, the Hospital for Sick Children, Toronto, ON, Canada
| | - Lily R Qiu
- Mouse Imaging Center, the Hospital for Sick Children, Toronto, ON, Canada
| | - Ramona M Rodriguiz
- Department of Psychiatry and Behavioral Sciences, Mouse Behavioral and Neuroendocrine Analysis Core Facility, Duke University Medical Center, Durham, NC, USA
| | - R M Henkelman
- Mouse Imaging Center, the Hospital for Sick Children, Toronto, ON, Canada
| | - Michael E Talkowski
- Center for Genomic Medicine and Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - William C Wetsel
- Department of Psychiatry and Behavioral Sciences, Mouse Behavioral and Neuroendocrine Analysis Core Facility, Duke University Medical Center, Durham, NC, USA
- Departments of Neurobiology and Cell Biology, Duke University Medical Center, Durham, NC, USA
| | - Christelle Golzio
- UMR 7104/INSERM U1258 and Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
| | - Nicholas Katsanis
- Center for Human Disease Modeling and Department of Cell Biology, Duke University, Durham, NC, USA
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19
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Lenoir S, Varangot A, Lebouvier L, Galli T, Hommet Y, Vivien D. Post-synaptic Release of the Neuronal Tissue-Type Plasminogen Activator (tPA). Front Cell Neurosci 2019; 13:164. [PMID: 31105531 PMCID: PMC6491899 DOI: 10.3389/fncel.2019.00164] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/08/2019] [Indexed: 11/13/2022] Open
Abstract
The neuronal serine protease tissue-type Plasminogen Activator (tPA) is an important player of the neuronal survival and of the synaptic plasticity. Thus, a better understanding the mechanisms regulating the neuronal trafficking of tPA is required to further understand how tPA can influence brain functions. Using confocal imaging including living cells and high-resolution cell imaging combined with an innovating labeling of tPA, we demonstrate that the neuronal tPA is contained in endosomal vesicles positives for Rabs and in exosomal vesicles positives for synaptobrevin-2 (VAMP2) in dendrites and axons. tPA-containing vesicles differ in their dynamics with the dendritic tPA containing-vesicles less mobile than the axonal tPA-containing vesicles, these laters displaying mainly a retrograde trafficking. Interestingly spontaneous exocytosis of tPA containing-vesicles occurs largely in dendrites.
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Affiliation(s)
- Sophie Lenoir
- Physiopathology and Imaging of Neurological Disorders, UNICAEN, INSERM, UMR-S U1237, Normandie Université, Caen, France
| | - Alexandre Varangot
- Physiopathology and Imaging of Neurological Disorders, UNICAEN, INSERM, UMR-S U1237, Normandie Université, Caen, France
| | - Laurent Lebouvier
- Physiopathology and Imaging of Neurological Disorders, UNICAEN, INSERM, UMR-S U1237, Normandie Université, Caen, France
| | - Thierry Galli
- Membrane Traffic in Healthy & Diseased Brain, Center of Psychiatry and Neurosciences, INSERM U894, Sorbonne Paris-Cité, Université Paris Descartes, Paris, France
| | - Yannick Hommet
- Physiopathology and Imaging of Neurological Disorders, UNICAEN, INSERM, UMR-S U1237, Normandie Université, Caen, France
| | - Denis Vivien
- Physiopathology and Imaging of Neurological Disorders, UNICAEN, INSERM, UMR-S U1237, Normandie Université, Caen, France.,Department of Clinical Research, Caen University Hospital, CHU Caen, Caen, France
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20
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Piccini A, Castroflorio E, Valente P, Guarnieri FC, Aprile D, Michetti C, Bramini M, Giansante G, Pinto B, Savardi A, Cesca F, Bachi A, Cattaneo A, Wren JD, Fassio A, Valtorta F, Benfenati F, Giovedì S. APache Is an AP2-Interacting Protein Involved in Synaptic Vesicle Trafficking and Neuronal Development. Cell Rep 2018; 21:3596-3611. [PMID: 29262337 DOI: 10.1016/j.celrep.2017.11.073] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 10/23/2017] [Accepted: 11/20/2017] [Indexed: 11/25/2022] Open
Abstract
Synaptic transmission is critically dependent on synaptic vesicle (SV) recycling. Although the precise mechanisms of SV retrieval are still debated, it is widely accepted that a fundamental role is played by clathrin-mediated endocytosis, a form of endocytosis that capitalizes on the clathrin/adaptor protein complex 2 (AP2) coat and several accessory factors. Here, we show that the previously uncharacterized protein KIAA1107, predicted by bioinformatics analysis to be involved in the SV cycle, is an AP2-interacting clathrin-endocytosis protein (APache). We found that APache is highly enriched in the CNS and is associated with clathrin-coated vesicles via interaction with AP2. APache-silenced neurons exhibit a severe impairment of maturation at early developmental stages, reduced SV density, enlarged endosome-like structures, and defects in synaptic transmission, consistent with an impaired clathrin/AP2-mediated SV recycling. Our data implicate APache as an actor in the complex regulation of SV trafficking, neuronal development, and synaptic plasticity.
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Affiliation(s)
- Alessandra Piccini
- Department of Experimental Medicine, University of Genova, 16132 Genova, Italy
| | - Enrico Castroflorio
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, 16132 Genova, Italy
| | - Pierluigi Valente
- Department of Experimental Medicine, University of Genova, 16132 Genova, Italy
| | - Fabrizia C Guarnieri
- San Raffaele Scientific Institute and Vita Salute University, 20132 Milano, Italy
| | - Davide Aprile
- Department of Experimental Medicine, University of Genova, 16132 Genova, Italy
| | - Caterina Michetti
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, 16132 Genova, Italy
| | - Mattia Bramini
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, 16132 Genova, Italy
| | - Giorgia Giansante
- Department of Experimental Medicine, University of Genova, 16132 Genova, Italy
| | - Bruno Pinto
- Local Micro-environment and Brain Development Laboratory, Istituto Italiano di Tecnologia, 16163 Genova, Italy; Bio@SNS, Scuola Normale Superiore, 56126 Pisa, Italy
| | - Annalisa Savardi
- Department of Experimental Medicine, University of Genova, 16132 Genova, Italy; Local Micro-environment and Brain Development Laboratory, Istituto Italiano di Tecnologia, 16163 Genova, Italy
| | - Fabrizia Cesca
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, 16132 Genova, Italy
| | - Angela Bachi
- IFOM, FIRC Institute of Molecular Oncology, 20132 Milano, Italy
| | - Angela Cattaneo
- IFOM, FIRC Institute of Molecular Oncology, 20132 Milano, Italy
| | - Jonathan D Wren
- Department of Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104-5005, USA
| | - Anna Fassio
- Department of Experimental Medicine, University of Genova, 16132 Genova, Italy; Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, 16132 Genova, Italy
| | - Flavia Valtorta
- San Raffaele Scientific Institute and Vita Salute University, 20132 Milano, Italy
| | - Fabio Benfenati
- Department of Experimental Medicine, University of Genova, 16132 Genova, Italy; Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, 16132 Genova, Italy.
| | - Silvia Giovedì
- Department of Experimental Medicine, University of Genova, 16132 Genova, Italy.
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21
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Knabbe J, Nassal JP, Verhage M, Kuner T. Secretory vesicle trafficking in awake and anaesthetized mice: differential speeds in axons versus synapses. J Physiol 2018; 596:3759-3773. [PMID: 29873393 DOI: 10.1113/jp276022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 05/24/2018] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Despite their immense physiological and pathophysiological importance, we know very little about the biology of dense core vesicle (DCV) trafficking in the intact mammalian brain. DCVs are transported at similar average speeds in the anaesthetized and awake mouse brain compared to neurons in culture, yet maximal speed and pausing fraction of transport were higher. Microtubule plus (+)-end extension imaging visualized microtubular growth at 0.12 μm/s and revealed that DCVs were transported faster in the anterograde direction. DCV transport slowed down upon presynaptic bouton approach, possibly promoting synaptic localization and cargo release. Our work provides a basis to extrapolate DCV transport properties determined in cultured neurons to the intact mouse brain and reveals novel features such as slowing upon bouton approach and brain state-dependent trafficking directionality. ABSTRACT Neuronal dense core vesicles (DCVs) transport many cargo molecules like neuropeptides and neurotrophins to their release sites in dendrites or axons. The transport properties of DCVs in axons of the intact mammalian brain are unknown. We used viral expression of a DCV cargo reporter (NPY-Venus/Cherry) in the thalamus and two-photon in vivo imaging to visualize axonal DCV trafficking in thalamocortical projections of anaesthetized and awake mice. We found an average speed of 1 μm/s, maximal speeds of up to 5 μm/s and a pausing fraction of ∼11%. Directionality of transport differed between anaesthetized and awake mice. In vivo microtubule +-end extension imaging using MACF18-GFP revealed microtubular growth at 0.12 μm/s and provided positive identification of antero- and retrograde axonal transport. Consistent with previous reports, anterograde transport was faster (∼2.1 μm/s) than retrograde transport (∼1.4 μm/s). In summary, DCVs are transported with faster maximal speeds and lower pausing fraction in vivo compared to previous results obtained in vitro. Finally, we found that DCVs slowed down upon presynaptic bouton approach. We propose that this mechanism promotes synaptic localization and cargo release.
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Affiliation(s)
- Johannes Knabbe
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Im Neuenheimer Feld 307, 69120, Heidelberg, Germany
| | - Joris Paul Nassal
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Im Neuenheimer Feld 307, 69120, Heidelberg, Germany.,Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU University Medical Center, De Boelelaan, 1087, 1081 HV Amsterdam, The Netherlands
| | - Matthijs Verhage
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU University Medical Center, De Boelelaan, 1087, 1081 HV Amsterdam, The Netherlands
| | - Thomas Kuner
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Im Neuenheimer Feld 307, 69120, Heidelberg, Germany
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22
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Kuznetsov IA, Kuznetsov AV. Simulating Reversibility of Dense Core Vesicles Capture in En Passant Boutons: Using Mathematical Modeling to Understand the Fate of Dense Core Vesicles in En Passant Boutons. J Biomech Eng 2018; 140:2658264. [PMID: 29049515 DOI: 10.1115/1.4038201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Indexed: 11/08/2022]
Abstract
The goal of this paper is to use mathematical modeling to investigate the fate of dense core vesicles (DCVs) captured in en passant boutons located in nerve terminals. One possibility is that all DCVs captured in boutons are destroyed, another possibility is that captured DCVs can escape and reenter the pool of transiting DCVs that move through the boutons, and a third possibility is that some DCVs are destroyed in boutons, while some reenter the transiting pool. We developed a model by applying the conservation of DCVs in various compartments composing the terminal, to predict different scenarios that emerge from the above assumptions about the fate of DCVs captured in boutons. We simulated DCV transport in type Ib and type III terminals. The simulations demonstrate that, if no DCV destruction in boutons is assumed and all captured DCVs reenter the transiting pool, the DCV fluxes evolve to a uniform circulation in a type Ib terminal at steady-state and the DCV flux remains constant from bouton to bouton. Because at steady-state the amount of captured DCVs is equal to the amount of DCVs that reenter the transiting pool, no decay of DCV fluxes occurs. In a type III terminal at steady-state, the anterograde DCV fluxes decay from bouton to bouton, while retrograde fluxes increase. This is explained by a larger capture efficiency of anterogradely moving DCVs than of retrogradely moving DCVs in type III boutons, while the captured DCVs that reenter the transiting pool are assumed to be equally split between anterogradely and retrogradely moving components. At steady-state, the physiologically reasonable assumption of no DCV destruction in boutons results in the same number of DCVs entering and leaving a nerve terminal. Because published experimental results indicate no DCV circulation in type III terminals, modeling results suggest that DCV transport in these type III terminals may not be at steady-state. To better understand the kinetics of DCV capture and release, future experiments in type III terminals at different times after DCV release (molting) may be proposed.
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Affiliation(s)
- I A Kuznetsov
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 e-mail:
| | - A V Kuznetsov
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910 e-mail:
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23
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Numakawa T, Odaka H, Adachi N. Actions of Brain-Derived Neurotrophic Factor and Glucocorticoid Stress in Neurogenesis. Int J Mol Sci 2017; 18:ijms18112312. [PMID: 29099059 PMCID: PMC5713281 DOI: 10.3390/ijms18112312] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 10/30/2017] [Accepted: 10/31/2017] [Indexed: 12/12/2022] Open
Abstract
Altered neurogenesis is suggested to be involved in the onset of brain diseases, including mental disorders and neurodegenerative diseases. Neurotrophic factors are well known for their positive effects on the proliferation/differentiation of both embryonic and adult neural stem/progenitor cells (NSCs/NPCs). Especially, brain-derived neurotrophic factor (BDNF) has been extensively investigated because of its roles in the differentiation/maturation of NSCs/NPCs. On the other hand, recent evidence indicates a negative impact of the stress hormone glucocorticoids (GCs) on the cell fate of NSCs/NPCs, which is also related to the pathophysiology of brain diseases, such as depression and autism spectrum disorder. Furthermore, studies including ours have demonstrated functional interactions between neurotrophic factors and GCs in neural events, including neurogenesis. In this review, we show and discuss relationships among the behaviors of NSCs/NPCs, BDNF, and GCs.
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Affiliation(s)
- Tadahiro Numakawa
- Department of Cell Modulation, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-8555, Japan.
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Tokyo 187-8551, Japan.
| | - Haruki Odaka
- Department of Cell Modulation, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-8555, Japan.
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, Tokyo 169-8050, Japan.
| | - Naoki Adachi
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University, Sanda City, Hyogo 662-8501, Japan.
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24
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Kobayashi T, Miyashita T, Murayama T, Toyoshima YY. Dynactin has two antagonistic regulatory domains and exerts opposing effects on dynein motility. PLoS One 2017; 12:e0183672. [PMID: 28850609 PMCID: PMC5574551 DOI: 10.1371/journal.pone.0183672] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 07/31/2017] [Indexed: 01/01/2023] Open
Abstract
Dynactin is a dynein-regulating protein that increases the processivity of dynein movement on microtubules. Recent studies have shown that a tripartite complex of dynein–dynactin–Bicaudal D2 is essential for highly processive movement. To elucidate the regulation of dynein motility by dynactin, we focused on two isoforms (A and B) of dynactin 1 (DCTN1), the largest subunit of dynactin that contains both microtubule- and dynein-binding domains. The only difference between the primary structures of the two isoforms is that DCTN1B lacks the K-rich domain, a cluster of basic residues. We measured dynein motility by single molecule observation of recombinant dynein and dynactin. Whereas the tripartite complex containing DCTN1A exhibited highly processive movement, the complex containing DCTN1B dissociated from microtubules with no apparent processive movement. This inhibitory effect of DCTN1B was caused by reductions of the microtubule-binding affinities of both dynein and dynactin, which was attributed to the coiled-coil 1 domain of DCTN1. In DCTN1A, the K-rich domain antagonized these inhibitory effects. Therefore, dynactin has two antagonistic domains and promotes or suppresses dynein motility to accomplish correct localization and functions of dynein within a cell.
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Affiliation(s)
- Takuya Kobayashi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Takuya Miyashita
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Takashi Murayama
- Department of Pharmacology, Juntendo University School of Medicine, Bunkyo-ku, Tokyo, Japan
| | - Yoko Y. Toyoshima
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan
- * E-mail:
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25
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Haziza S, Mohan N, Loe-Mie Y, Lepagnol-Bestel AM, Massou S, Adam MP, Le XL, Viard J, Plancon C, Daudin R, Koebel P, Dorard E, Rose C, Hsieh FJ, Wu CC, Potier B, Herault Y, Sala C, Corvin A, Allinquant B, Chang HC, Treussart F, Simonneau M. Fluorescent nanodiamond tracking reveals intraneuronal transport abnormalities induced by brain-disease-related genetic risk factors. NATURE NANOTECHNOLOGY 2017; 12:322-328. [PMID: 27893730 DOI: 10.1038/nnano.2016.260] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 10/24/2016] [Indexed: 05/24/2023]
Abstract
Brain diseases such as autism and Alzheimer's disease (each inflicting >1% of the world population) involve a large network of genes displaying subtle changes in their expression. Abnormalities in intraneuronal transport have been linked to genetic risk factors found in patients, suggesting the relevance of measuring this key biological process. However, current techniques are not sensitive enough to detect minor abnormalities. Here we report a sensitive method to measure the changes in intraneuronal transport induced by brain-disease-related genetic risk factors using fluorescent nanodiamonds (FNDs). We show that the high brightness, photostability and absence of cytotoxicity allow FNDs to be tracked inside the branches of dissociated neurons with a spatial resolution of 12 nm and a temporal resolution of 50 ms. As proof of principle, we applied the FND tracking assay on two transgenic mouse lines that mimic the slight changes in protein concentration (∼30%) found in the brains of patients. In both cases, we show that the FND assay is sufficiently sensitive to detect these changes.
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Affiliation(s)
- Simon Haziza
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Université Paris-Saclay, 91405 Orsay, France
- Centre de Psychiatrie et Neurosciences, INSERM U894, Université Paris-Descartes, 75014 Paris, France
| | - Nitin Mohan
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Université Paris-Saclay, 91405 Orsay, France
| | - Yann Loe-Mie
- Centre de Psychiatrie et Neurosciences, INSERM U894, Université Paris-Descartes, 75014 Paris, France
| | | | - Sophie Massou
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Université Paris-Saclay, 91405 Orsay, France
| | - Marie-Pierre Adam
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Université Paris-Saclay, 91405 Orsay, France
| | - Xuan Loc Le
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Université Paris-Saclay, 91405 Orsay, France
| | - Julia Viard
- Centre de Psychiatrie et Neurosciences, INSERM U894, Université Paris-Descartes, 75014 Paris, France
| | - Christine Plancon
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Institut de Génomique, Centre National de Génotypage, 91057 Evry, France
| | - Rachel Daudin
- Centre de Psychiatrie et Neurosciences, INSERM U894, Université Paris-Descartes, 75014 Paris, France
| | - Pascale Koebel
- Institut de génétique et de biologie moléculaire et cellulaire, CNRS UMR 7104, INSERM U 964, Université de Strasbourg, 67400 Illkirch-Graffenstaden, France
| | - Emilie Dorard
- Centre de Psychiatrie et Neurosciences, INSERM U894, Université Paris-Descartes, 75014 Paris, France
| | - Christiane Rose
- Centre de Psychiatrie et Neurosciences, INSERM U894, Université Paris-Descartes, 75014 Paris, France
| | - Feng-Jen Hsieh
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
| | - Chih-Che Wu
- Department of Applied Chemistry, National Chi Nan University, Puli, Nantou Hsien 545, Taiwan
| | - Brigitte Potier
- Centre de Psychiatrie et Neurosciences, INSERM U894, Université Paris-Descartes, 75014 Paris, France
| | - Yann Herault
- Institut de génétique et de biologie moléculaire et cellulaire, CNRS UMR 7104, INSERM U 964, Université de Strasbourg, 67400 Illkirch-Graffenstaden, France
| | - Carlo Sala
- Neuroscience Institute, CNR, 20129 Milano, Italy
| | - Aiden Corvin
- Department of Psychiatry, Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
| | - Bernadette Allinquant
- Centre de Psychiatrie et Neurosciences, INSERM U894, Université Paris-Descartes, 75014 Paris, France
| | - Huan-Cheng Chang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
| | - François Treussart
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Université Paris-Saclay, 91405 Orsay, France
| | - Michel Simonneau
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Université Paris-Saclay, 91405 Orsay, France
- Centre de Psychiatrie et Neurosciences, INSERM U894, Université Paris-Descartes, 75014 Paris, France
- Department of Biology, ENS Cachan, Université Paris-Saclay, 94235 Cachan, France
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26
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Emperador Melero J, Nadadhur AG, Schut D, Weering JV, Heine VM, Toonen RF, Verhage M. Differential Maturation of the Two Regulated Secretory Pathways in Human iPSC-Derived Neurons. Stem Cell Reports 2017; 8:659-672. [PMID: 28238793 PMCID: PMC5355645 DOI: 10.1016/j.stemcr.2017.01.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 01/22/2017] [Accepted: 01/23/2017] [Indexed: 12/25/2022] Open
Abstract
Neurons communicate by regulated secretion of chemical signals from synaptic vesicles (SVs) and dense-core vesicles (DCVs). Here, we investigated the maturation of these two secretory pathways in micro-networks of human iPSC-derived neurons. These micro-networks abundantly expressed endogenous SV and DCV markers, including neuropeptides. DCV transport was microtubule dependent, preferentially anterograde in axons, and 2-fold faster in axons than in dendrites. SV and DCV secretion were strictly Ca2+ and SNARE dependent. DCV secretion capacity matured until day in vitro (DIV) 36, with intense stimulation releasing 6% of the total DCV pool, and then plateaued. This efficiency is comparable with mature mouse neurons. In contrast, SV secretion capacity continued to increase until DIV50, with substantial further increase in secretion efficiency and decrease in silent synapses. These data show that the two secretory pathways can be studied in human neurons and that they mature differentially, with DCV secretion reaching maximum efficiency when that of SVs is still low.
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Affiliation(s)
- Javier Emperador Melero
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit (VU) Amsterdam and VU Medical Center, de Boelelaan 1087, 1081 HV Amsterdam, the Netherlands
| | - Aishwarya G Nadadhur
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit (VU) Amsterdam and VU Medical Center, de Boelelaan 1087, 1081 HV Amsterdam, the Netherlands
| | - Desiree Schut
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit (VU) Amsterdam and VU Medical Center, de Boelelaan 1087, 1081 HV Amsterdam, the Netherlands
| | - Jan V Weering
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit (VU) Amsterdam and VU Medical Center, de Boelelaan 1087, 1081 HV Amsterdam, the Netherlands
| | - Vivi M Heine
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit (VU) Amsterdam and VU Medical Center, de Boelelaan 1087, 1081 HV Amsterdam, the Netherlands; Department of Pediatrics/Child Neurology, Amsterdam Neuroscience, VU Medical Center, 1081 HV Amsterdam, the Netherlands; Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, the Netherlands
| | - Ruud F Toonen
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit (VU) Amsterdam and VU Medical Center, de Boelelaan 1087, 1081 HV Amsterdam, the Netherlands.
| | - Matthijs Verhage
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit (VU) Amsterdam and VU Medical Center, de Boelelaan 1087, 1081 HV Amsterdam, the Netherlands.
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27
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Hinckelmann MV, Virlogeux A, Niehage C, Poujol C, Choquet D, Hoflack B, Zala D, Saudou F. Self-propelling vesicles define glycolysis as the minimal energy machinery for neuronal transport. Nat Commun 2016; 7:13233. [PMID: 27775035 PMCID: PMC5078996 DOI: 10.1038/ncomms13233] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 09/14/2016] [Indexed: 12/21/2022] Open
Abstract
The glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) facilitates fast axonal transport in neurons. However, given that GAPDH does not produce ATP, it is unclear whether glycolysis per se is sufficient to propel vesicles. Although many proteins regulating transport have been identified, the molecular composition of transported vesicles in neurons has yet to be fully elucidated. Here we selectively enrich motile vesicles and perform quantitative proteomic analysis. In addition to the expected molecular motors and vesicular proteins, we find an enrichment of all the glycolytic enzymes. Using biochemical approaches and super-resolution microscopy, we observe that most glycolytic enzymes are selectively associated with vesicles and facilitate transport of vesicles in neurons. Finally, we provide evidence that mouse brain vesicles produce ATP from ADP and glucose, and display movement in a reconstituted in vitro transport assay of native vesicles. We conclude that transport of vesicles along microtubules can be autonomous. How neurons produce energy to fuel fast axonal transport is only partially understood. Authors here report that most glycolytic enzymes are enriched in motile vesicles, and such glycolytic machinery can produce ATP autonomously to propel vesicle movement along microtubules in a cell-free assay.
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Affiliation(s)
- María-Victoria Hinckelmann
- Institut Curie, F-91405 Orsay, France.,CNRS, UMR3306, F-91405 Orsay, France.,Inserm, U1005, F-91405 Orsay, France.,Faculté de Médecine, Univ. Paris Sud11, F-94276 Le Kremlin-Bicêtre, France
| | - Amandine Virlogeux
- Institut Curie, F-91405 Orsay, France.,CNRS, UMR3306, F-91405 Orsay, France.,Inserm, U1005, F-91405 Orsay, France.,Faculté de Médecine, Univ. Paris Sud11, F-94276 Le Kremlin-Bicêtre, France.,Grenoble Institut des Neurosciences, GIN, Univ. Grenoble Alpes, F-38000 Grenoble, France.,Inserm, U1216, F-38000 Grenoble, France
| | - Christian Niehage
- Biotechnology Center, Technische Universität Dresden, D-01307 Dresden, Germany
| | - Christel Poujol
- CNRS, UMR 5297, F-33000 Bordeaux, France.,Interdisciplinary Institute for Neuroscience, IINS, Univ. Bordeaux, F-33077 Bordeaux, France
| | - Daniel Choquet
- CNRS, UMR 5297, F-33000 Bordeaux, France.,Interdisciplinary Institute for Neuroscience, IINS, Univ. Bordeaux, F-33077 Bordeaux, France
| | - Bernard Hoflack
- Biotechnology Center, Technische Universität Dresden, D-01307 Dresden, Germany
| | - Diana Zala
- Institut Curie, F-91405 Orsay, France.,CNRS, UMR3306, F-91405 Orsay, France.,Inserm, U1005, F-91405 Orsay, France
| | - Frédéric Saudou
- Institut Curie, F-91405 Orsay, France.,CNRS, UMR3306, F-91405 Orsay, France.,Inserm, U1005, F-91405 Orsay, France.,Grenoble Institut des Neurosciences, GIN, Univ. Grenoble Alpes, F-38000 Grenoble, France.,Inserm, U1216, F-38000 Grenoble, France.,CHU Grenoble Alpes, F-38000 Grenoble, France
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28
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van de Willige D, Hoogenraad CC, Akhmanova A. Microtubule plus-end tracking proteins in neuronal development. Cell Mol Life Sci 2016; 73:2053-77. [PMID: 26969328 PMCID: PMC4834103 DOI: 10.1007/s00018-016-2168-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Revised: 02/04/2016] [Accepted: 02/22/2016] [Indexed: 11/28/2022]
Abstract
Regulation of the microtubule cytoskeleton is of pivotal importance for neuronal development and function. One such regulatory mechanism centers on microtubule plus-end tracking proteins (+TIPs): structurally and functionally diverse regulatory factors, which can form complex macromolecular assemblies at the growing microtubule plus-ends. +TIPs modulate important properties of microtubules including their dynamics and their ability to control cell polarity, membrane transport and signaling. Several neurodevelopmental and neurodegenerative diseases are associated with mutations in +TIPs or with misregulation of these proteins. In this review, we focus on the role and regulation of +TIPs in neuronal development and associated disorders.
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Affiliation(s)
- Dieudonnée van de Willige
- Cell Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Casper C Hoogenraad
- Cell Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
| | - Anna Akhmanova
- Cell Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
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29
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Amyloid-Beta Induced Changes in Vesicular Transport of BDNF in Hippocampal Neurons. Neural Plast 2016; 2016:4145708. [PMID: 26881108 PMCID: PMC4736975 DOI: 10.1155/2016/4145708] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/26/2015] [Accepted: 11/29/2015] [Indexed: 12/15/2022] Open
Abstract
The neurotrophin brain derived neurotrophic factor (BDNF) is an important growth factor in the CNS. Deficits in transport of this secretory protein could underlie neurodegenerative diseases. Investigation of disease-related changes in BDNF transport might provide insights into the cellular mechanism underlying, for example, Alzheimer's disease (AD). To analyze the role of BDNF transport in AD, live cell imaging of fluorescently labeled BDNF was performed in hippocampal neurons of different AD model systems. BDNF and APP colocalized with low incidence in vesicular structures. Anterograde as well as retrograde transport of BDNF vesicles was reduced and these effects were mediated by factors released from hippocampal neurons into the extracellular medium. Transport of BDNF was altered at a very early time point after onset of human APP expression or after acute amyloid-beta(1-42) treatment, while the activity-dependent release of BDNF remained unaffected. Taken together, extracellular cleavage products of APP induced rapid changes in anterograde and retrograde transport of BDNF-containing vesicles while release of BDNF was unaffected by transgenic expression of mutated APP. These early transport deficits might lead to permanently impaired brain functions in the adult brain.
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30
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An L, Li G, Si J, Zhang C, Han X, Wang S, Jiang L, Xie K. Acrylamide Retards the Slow Axonal Transport of Neurofilaments in Rat Cultured Dorsal Root Ganglia Neurons and the Corresponding Mechanisms. Neurochem Res 2015; 41:1000-9. [PMID: 26721510 DOI: 10.1007/s11064-015-1782-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Revised: 11/02/2015] [Accepted: 11/20/2015] [Indexed: 01/09/2023]
Abstract
Chronic acrylamide (ACR) exposure induces peripheral-central axonopathy in occupational workers and laboratory animals, but the underlying mechanisms remain unclear. In this study, we first investigated the effects of ACR on slow axonal transport of neurofilaments in cultured rat dorsal root ganglia (DRG) neurons through live-cell imaging approach. Then for the underlying mechanisms exploration, the protein level of neurofilament subunits, motor proteins kinesin and dynein, and dynamitin subunit of dynactin in DRG neurons were assessed by western blotting and the concentrations of ATP was detected using ATP Assay Kit. The results showed that ACR treatment results in a dose-dependent decrease of slow axonal transport of neurofilaments. Furthermore, ACR intoxication significantly increases the protein levels of the three neurofilament subunits (NF-L, NF-M, NF-H), kinesin, dynein, and dynamitin subunit of dynactin in DRG neurons. In addition, ATP level decreased significantly in ACR-treated DRG neurons. Our findings indicate that ACR exposure retards slow axonal transport of NF-M, and suggest that the increase of neurofilament cargoes, motor proteins, dynamitin of dynactin, and the inadequate ATP supply contribute to the ACR-induced retardation of slow axonal transport.
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Affiliation(s)
- Lihong An
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, 250012, China.,Institute of Environment and Health, School of Public Health, Shandong University, Jinan, 250012, China
| | - Guozhen Li
- Beijing Municipal Institute of Labour Protection, Taoranting Road, Xicheng District, Beijing, 100054, China
| | - Jiliang Si
- Institute of Environment and Health, School of Public Health, Shandong University, Jinan, 250012, China
| | - Cuili Zhang
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, 250012, China
| | - Xiaoying Han
- College of Life Sciences, Shandong Normal University, Jinan, 250014, China
| | - Shuo Wang
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, 250012, China
| | - Lulu Jiang
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, 250012, China
| | - Keqin Xie
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, 250012, China.
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31
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Umeda T, Ramser EM, Yamashita M, Nakajima K, Mori H, Silverman MA, Tomiyama T. Intracellular amyloid β oligomers impair organelle transport and induce dendritic spine loss in primary neurons. Acta Neuropathol Commun 2015; 3:51. [PMID: 26293809 PMCID: PMC4546183 DOI: 10.1186/s40478-015-0230-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 08/09/2015] [Indexed: 12/15/2022] Open
Abstract
Introduction Synaptic dysfunction and intracellular transport defects are early events in Alzheimer’s disease (AD). Extracellular amyloid β (Aβ) oligomers cause spine alterations and impede the transport of proteins and organelles such as brain-derived neurotrophic factor (BDNF) and mitochondria that are required for synaptic function. Meanwhile, intraneuronal accumulation of Aβ precedes its extracellular deposition and is also associated with synaptic dysfunction in AD. However, the links between intracellular Aβ, spine alteration, and mechanisms that support synaptic maintenance such as organelle trafficking are poorly understood. Results We compared the effects of wild-type and Osaka (E693Δ)-mutant amyloid precursor proteins: the former secretes Aβ into extracellular space and the latter accumulates Aβ oligomers within cells. First we investigated the effects of intracellular Aβ oligomers on dendritic spines in primary neurons and their tau-dependency using tau knockout neurons. We found that intracellular Aβ oligomers caused a reduction in mushroom, or mature spines, independently of tau. We also found that intracellular Aβ oligomers significantly impaired the intracellular transport of BDNF, mitochondria, and recycling endosomes: cargoes essential for synaptic maintenance. A reduction in BDNF transport by intracellular Aβ oligomers was also observed in tau knockout neurons. Conclusions Our findings indicate that intracellular Aβ oligomers likely contribute to early synaptic pathology in AD and argue against the consensus that Aβ-induced spine loss and transport defects require tau.
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32
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Can an increase in neuropeptide production in the soma lead to DCV circulation in axon terminals with type III en passant boutons? Math Biosci 2015; 267:61-78. [PMID: 26122837 DOI: 10.1016/j.mbs.2015.06.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 05/26/2015] [Accepted: 06/18/2015] [Indexed: 01/08/2023]
Abstract
Neuropeptides are synthesized in the neuron soma; they are packaged in dense core vesicles (DCVs) which undergo axonal transport toward nerve terminals. Published experimental results suggest that in terminals with type Ib boutons DCVs circulate in the terminal, undergoing repeated anterograde and retrograde transport, while in type III terminals DCVs do not circulate in the terminal. In this paper we developed a mathematical model that allowed us to investigate the effects of an increased rate of DCV production in the soma. We demonstrated that our model reproduces some important experimental results, in particular those concerning DCV circulation in type Ib and type III terminals. Our model makes testable predictions. Probably the most important prediction concerns the effect of an increased DCV production rate in the soma, which we anticipate leads to increased DCV circulation in type Ib boutons and to the appearance of DCV circulation in type III boutons. Other predictions concern various stages of development of DCV circulation in the terminals after they were depleted of DCVs due to neuropeptide release.
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33
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Cavolo SL, Zhou C, Ketcham SA, Suzuki MM, Ukalovic K, Silverman MA, Schroer TA, Levitan ES. Mycalolide B dissociates dynactin and abolishes retrograde axonal transport of dense-core vesicles. Mol Biol Cell 2015; 26:2664-72. [PMID: 26023088 PMCID: PMC4501363 DOI: 10.1091/mbc.e14-11-1564] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 05/19/2015] [Indexed: 11/21/2022] Open
Abstract
Although dynactin was believed to be a bidirectional facilitator of axonal transport, here mycalolide B is identified as a dynactin dissociator and shown to selectively abolish retrograde axonal transport of dense-core vesicles in hippocampal and Drosophila neurons. Thus dynactin has a strict obligatory unidirectional role in axonal transport. Axonal transport is critical for maintaining synaptic transmission. Of interest, anterograde and retrograde axonal transport appear to be interdependent, as perturbing one directional motor often impairs movement in the opposite direction. Here live imaging of Drosophila and hippocampal neuron dense-core vesicles (DCVs) containing a neuropeptide or brain-derived neurotrophic factor shows that the F-actin depolymerizing macrolide toxin mycalolide B (MB) rapidly and selectively abolishes retrograde, but not anterograde, transport in the axon and the nerve terminal. Latrunculin A does not mimic MB, demonstrating that F-actin depolymerization is not responsible for unidirectional transport inhibition. Given that dynactin initiates retrograde transport and that amino acid sequences implicated in macrolide toxin binding are found in the dynactin component actin-related protein 1, we examined dynactin integrity. Remarkably, cell extract and purified protein experiments show that MB induces disassembly of the dynactin complex. Thus imaging selective retrograde transport inhibition led to the discovery of a small-molecule dynactin disruptor. The rapid unidirectional inhibition by MB suggests that dynactin is absolutely required for retrograde DCV transport but does not directly facilitate ongoing anterograde DCV transport in the axon or nerve terminal. More generally, MB's effects bolster the conclusion that anterograde and retrograde axonal transport are not necessarily interdependent.
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Affiliation(s)
- Samantha L Cavolo
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Chaoming Zhou
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261
| | | | - Matthew M Suzuki
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Kresimir Ukalovic
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Michael A Silverman
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Trina A Schroer
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218
| | - Edwin S Levitan
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261
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34
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Castorina A, Waschek JA, Marzagalli R, Cardile V, Drago F. PACAP interacts with PAC1 receptors to induce tissue plasminogen activator (tPA) expression and activity in schwann cell-like cultures. PLoS One 2015; 10:e0117799. [PMID: 25658447 PMCID: PMC4319891 DOI: 10.1371/journal.pone.0117799] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 12/31/2014] [Indexed: 12/13/2022] Open
Abstract
Regeneration of peripheral nerves depends on the abilities of rejuvenating axons to migrate at the injury site through cellular debris and altered extracellular matrix, and then grow along the residual distal nerve sheath conduit and reinnervate synaptic targets. Considerable evidence suggest that glial cells participate in this process, although the mechanisms remain to be clarified. In cell culture, regenerating neurites secrete PACAP, a peptide shown to induce the expression of the protease tissue plasminogen activator (tPA) in neural cell types. In the present studies, we tested the hypothesis that PACAP can stimulate peripheral glial cells to produce tPA. More specifically, we addressed whether or not PACAP promoted the expression and activity of tPA in the Schwann cell line RT4-D6P2T, which shares biochemical and physical properties with Schwann cells. We found that PACAP dose- and time-dependently stimulated tPA expression both at the mRNA and protein level. Such effect was mimicked by maxadilan, a potent PAC1 receptor agonist, but not by the PACAP-related homolog VIP, suggesting a PAC1-mediated function. These actions appeared to be mediated at least in part by the Akt/CREB signaling cascade because wortmannin, a PI3K inhibitor, prevented peptide-driven CREB phosphorylation and tPA increase. Interestingly, treatment with BDNF mimicked PACAP actions on tPA, but acted through both the Akt and MAPK signaling pathways, while causing a robust increase in PACAP and PAC1 expression. PACAP6-38 totally blocked PACAP-driven tPA expression and in part hampered BDNF-mediated effects. We conclude that PACAP, acting through PAC1 receptors, stimulates tPA expression and activity in a Akt/CREB-dependent manner to promote proteolytic activity in Schwann-cell like cultures.
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Affiliation(s)
- Alessandro Castorina
- Department of Biomedical Sciences and Biotechnologies, Section of Human Anatomy and Histology, University of Catania, Catania, Italy
- * E-mail:
| | - James A. Waschek
- Semel Institute/Department of Psychiatry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Rubina Marzagalli
- Department of Biomedical Sciences and Biotechnologies, Section of Human Anatomy and Histology, University of Catania, Catania, Italy
| | - Venera Cardile
- Department of Biomedical Sciences and Biotechnologies, Section of Physiology, University of Catania, Catania, Italy
| | - Filippo Drago
- Department of Biomedical Sciences and Biotechnologies, Section of Pharmacology, University of Catania, Catania, Italy
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Takach O, Gill TB, Silverman MA. Modulation of insulin signaling rescues BDNF transport defects independent of tau in amyloid-β oligomer-treated hippocampal neurons. Neurobiol Aging 2014; 36:1378-82. [PMID: 25543463 DOI: 10.1016/j.neurobiolaging.2014.11.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 10/21/2014] [Accepted: 11/25/2014] [Indexed: 10/24/2022]
Abstract
Defective brain insulin signaling contributes to the cognitive deficits in Alzheimer's disease (AD). Amyloid-beta oligomers (AβOs), the primary neurotoxin implicated in AD, downregulate insulin signaling by impairing protein kinase B/AKT, thereby overactivating glycogen synthase kinase-3β. By this mechanism, AβOs may also impair axonal transport before tau-induced cytoskeletal collapse and cell death. Here, we demonstrate that a constitutively active form of protein kinase B/AKT prevents brain-derived neurotrophic factor (BDNF) transport defects in AβO-treated primary neurons from wild type (tau(+/+)) and tau knockout (tau(-/-)) mice. Remarkably, inhibition of glycogen synthase kinase-3β rescues BDNF transport defects independent of tau. Furthermore, exendin-4, an anti-diabetes agent, restores normal BDNF axonal transport by stimulating the glucagon-like peptide-1 receptor to activate the insulin pathway. Collectively, our findings indicate that normalized insulin signaling can both prevent and reverse BDNF transport defects in AβO-treated neurons. Ultimately, this work may reveal novel therapeutic targets that regulate BDNF trafficking, promote its secretion and uptake, and prolong neuronal survival during AD progression.
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Affiliation(s)
- Oliver Takach
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Trevor B Gill
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Michael A Silverman
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada; Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
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Adachi N, Numakawa T, Richards M, Nakajima S, Kunugi H. New insight in expression, transport, and secretion of brain-derived neurotrophic factor: Implications in brain-related diseases. World J Biol Chem 2014; 5:409-428. [PMID: 25426265 PMCID: PMC4243146 DOI: 10.4331/wjbc.v5.i4.409] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 06/10/2014] [Accepted: 08/31/2014] [Indexed: 02/05/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) attracts increasing attention from both research and clinical fields because of its important functions in the central nervous system. An adequate amount of BDNF is critical to develop and maintain normal neuronal circuits in the brain. Given that loss of BDNF function has been reported in the brains of patients with neurodegenerative or psychiatric diseases, understanding basic properties of BDNF and associated intracellular processes is imperative. In this review, we revisit the gene structure, transcription, translation, transport and secretion mechanisms of BDNF. We also introduce implications of BDNF in several brain-related diseases including Alzheimer’s disease, Huntington’s disease, depression and schizophrenia.
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Makani V, Sultana R, Sie KS, Orjiako D, Tatangelo M, Dowling A, Cai J, Pierce W, Butterfield DA, Hill J, Park J. Annexin A1 complex mediates oxytocin vesicle transport. J Neuroendocrinol 2013; 25:1241-1254. [PMID: 24118254 PMCID: PMC3975805 DOI: 10.1111/jne.12112] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 09/24/2013] [Accepted: 09/29/2013] [Indexed: 12/20/2022]
Abstract
Oxytocin is a major neuropeptide that modulates the brain functions involved in social behaviour and interaction. Despite of the importance of oxytocin for the neural control of social behaviour, little is known about the molecular mechanism(s) by which oxytocin secretion in the brain is regulated. Pro-oxytocin is synthesised in the cell bodies of hypothalamic neurones in the supraoptic and paraventricular nuclei and processed to a 9-amino-acid mature form during post-Golgi transport to the secretion sites at the axon terminals and somatodendritic regions. Oxytocin secreted from the somatodendritic regions diffuses throughout the hypothalamus and its neighbouring brain regions. Some oxytocin-positive axons innervate and secrete oxytocin to the brain regions distal to the hypothalamus. Brain oxytocin binds to its receptors in the brain regions involved in social behaviour. Oxytocin is also secreted from the axon terminal at the posterior pituitary gland into the blood circulation. We have discovered a new molecular complex consisting of annexin A1 (ANXA1), A-kinase anchor protein 150 (AKAP150) and microtubule motor that controls the distribution of oxytocin vesicles between the axon and the cell body in a protein kinase A (PKA)- and protein kinase C (PKC)-sensitive manner. ANXA1 showed significant co-localisation with oxytocin vesicles. Activation of PKA enhanced the association of kinesin-2 with ANXA1, thus increasing the axon-localisation of oxytocin vesicles. Conversely, activation of PKC decreased the binding of kinesin-2 to ANXA1, thus attenuating the axon-localisation of oxytocin vesicles. The result of the present study suggest that ANXA1 complex coordinates the actions of PKA and PKC to control the distribution of oxytocin vesicles between the axon and the cell body.
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Affiliation(s)
- Vishruti Makani
- Department of Neurosciences, University of Toledo, College of Medicine, Toledo, OH 43614
| | - Rukhsana Sultana
- Department of Chemistry, University of Kentucky, Lexington, KY 40506
| | - Khin Sander Sie
- Department of Neurosciences, University of Toledo, College of Medicine, Toledo, OH 43614
| | - Doris Orjiako
- Department of Neurosciences, University of Toledo, College of Medicine, Toledo, OH 43614
| | - Marco Tatangelo
- Department of Neurosciences, University of Toledo, College of Medicine, Toledo, OH 43614
| | - Abigail Dowling
- Department of Physiology and Pharmacology, University of Toledo, College of Medicine, Toledo, OH 43614
| | - Jian Cai
- Department of Pharmacology, University of Louisville, Louisville, KY 40292
| | - William Pierce
- Department of Pharmacology, University of Louisville, Louisville, KY 40292
| | | | - Jennifer Hill
- Department of Physiology and Pharmacology, University of Toledo, College of Medicine, Toledo, OH 43614
| | - Joshua Park
- Department of Neurosciences, University of Toledo, College of Medicine, Toledo, OH 43614
- To whom correspondence should be addressed. Department of Neurosciences, University of Toledo College of Medicine, Toledo, Ohio 43614, , Phone: (419) 383-4085, Fax: (419) 383-3008
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Castle MJ, Perlson E, Holzbaur EL, Wolfe JH. Long-distance axonal transport of AAV9 is driven by dynein and kinesin-2 and is trafficked in a highly motile Rab7-positive compartment. Mol Ther 2013; 22:554-566. [PMID: 24100640 DOI: 10.1038/mt.2013.237] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 09/30/2013] [Indexed: 12/15/2022] Open
Abstract
Adeno-associated virus (AAV) vectors can move along axonal pathways after brain injection, resulting in transduction of distal brain regions. This can enhance the spread of therapeutic gene transfer and improve treatment of neurogenetic disorders that require global correction. To better understand the underlying cellular mechanisms that drive AAV trafficking in neurons, we investigated the axonal transport of dye-conjugated AAV9, utilizing microfluidic primary neuron cultures that isolate cell bodies from axon termini and permit independent analysis of retrograde and anterograde axonal transport. After entry, AAV was trafficked into nonmotile early and recycling endosomes, exocytic vesicles, and a retrograde-directed late endosome/lysosome compartment. Rab7-positive late endosomes/lysosomes that contained AAV were highly motile, exhibiting faster retrograde velocities and less pausing than Rab7-positive endosomes without virus. Inhibitor experiments indicated that the retrograde transport of AAV within these endosomes is driven by cytoplasmic dynein and requires Rab7 function, whereas anterograde transport of AAV is driven by kinesin-2 and exhibits unusually rapid velocities. Furthermore, increasing AAV9 uptake by neuraminidase treatment significantly enhanced virus transport in both directions. These findings provide novel insights into AAV trafficking within neurons, which should enhance progress toward the utilization of AAV for improved distribution of transgene delivery within the brain.
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Affiliation(s)
- Michael J Castle
- Research Institute of the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; W.F. Goodman Center for Comparative Medical Genetics, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Eran Perlson
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Erika Lf Holzbaur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - John H Wolfe
- Research Institute of the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; W.F. Goodman Center for Comparative Medical Genetics, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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Kuznetsov IA, Kuznetsov AV. Modelling organelle transport after traumatic axonal injury. Comput Methods Biomech Biomed Engin 2013; 18:583-91. [PMID: 23947620 DOI: 10.1080/10255842.2013.820721] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
This paper is motivated by recent experimental research (Tang-Schomer et al. 2012) on the formation of periodic varicosities in axons after traumatic brain injury (TBI). TBI leads to the formation of undulated distortions in the axons due to their dynamic deformation. These distortions result in the breakage of some microtubules (MTs) near the peaks of undulations. The breakage is followed by catastrophic MT depolymerisation around the broken ends. Although after relaxation axons regain their straight geometry, the structure of the axon after TBI is characterised by the presence of periodic regions where the density of MTs has been decreased due to depolymerisation. We modelled organelle transport in an axon segment with such a damaged MT structure and investigated how this structure affects the distributions of organelle concentrations and fluxes. The modelling results suggest that organelles accumulate at the boundaries of the region where the density of MTs has been decreased by depolymerisation. According to the model, the presence of such damaged regions decreases the organelle flux by only about 12%. This provides evidence that axon degradation after TBI may be caused by organelle accumulation rather than by starvation due to insufficient organelle flux.
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Affiliation(s)
- I A Kuznetsov
- a Department of Biomedical Engineering , Johns Hopkins University , Baltimore , MD 21218-2694 , USA
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Ramser EM, Gan KJ, Decker H, Fan EY, Suzuki MM, Ferreira ST, Silverman MA. Amyloid-β oligomers induce tau-independent disruption of BDNF axonal transport via calcineurin activation in cultured hippocampal neurons. Mol Biol Cell 2013; 24:2494-505. [PMID: 23783030 PMCID: PMC3744947 DOI: 10.1091/mbc.e12-12-0858] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The role of tau in axonal transport disruption during early-stage Alzheimer disease is controversial. The amyloid-β oligomers markedly impair BDNF transport in primary wild-type and tau-knockout neurons. This occurs by nonexcitotoxic activation of calcineurin, and inhibition of calcineurin rescues transport defects independent of tau. Disruption of fast axonal transport (FAT) is an early pathological event in Alzheimer's disease (AD). Soluble amyloid-β oligomers (AβOs), increasingly recognized as proximal neurotoxins in AD, impair organelle transport in cultured neurons and transgenic mouse models. AβOs also stimulate hyperphosphorylation of the axonal microtubule-associated protein, tau. However, the role of tau in FAT disruption is controversial. Here we show that AβOs reduce vesicular transport of brain-derived neurotrophic factor (BDNF) in hippocampal neurons from both wild-type and tau-knockout mice, indicating that tau is not required for transport disruption. FAT inhibition is not accompanied by microtubule destabilization or neuronal death. Significantly, inhibition of calcineurin (CaN), a calcium-dependent phosphatase implicated in AD pathogenesis, rescues BDNF transport. Moreover, inhibition of protein phosphatase 1 and glycogen synthase kinase 3β, downstream targets of CaN, prevents BDNF transport defects induced by AβOs. We further show that AβOs induce CaN activation through nonexcitotoxic calcium signaling. Results implicate CaN in FAT regulation and demonstrate that tau is not required for AβO-induced BDNF transport disruption.
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Affiliation(s)
- Elisa M Ramser
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
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Zala D, Hinckelmann MV, Yu H, Lyra da Cunha MM, Liot G, Cordelières FP, Marco S, Saudou F. Vesicular glycolysis provides on-board energy for fast axonal transport. Cell 2013; 152:479-91. [PMID: 23374344 DOI: 10.1016/j.cell.2012.12.029] [Citation(s) in RCA: 335] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 07/11/2012] [Accepted: 12/10/2012] [Indexed: 01/10/2023]
Abstract
Fast axonal transport (FAT) requires consistent energy over long distances to fuel the molecular motors that transport vesicles. We demonstrate that glycolysis provides ATP for the FAT of vesicles. Although inhibiting ATP production from mitochondria did not affect vesicles motility, pharmacological or genetic inhibition of the glycolytic enzyme GAPDH reduced transport in cultured neurons and in Drosophila larvae. GAPDH localizes on vesicles via a huntingtin-dependent mechanism and is transported on fast-moving vesicles within axons. Purified motile vesicles showed GAPDH enzymatic activity and produced ATP. Finally, we show that vesicular GAPDH is necessary and sufficient to provide on-board energy for fast vesicular transport. Although detaching GAPDH from vesicles reduced transport, targeting GAPDH to vesicles was sufficient to promote FAT in GAPDH deficient neurons. This specifically localized glycolytic machinery may supply constant energy, independent of mitochondria, for the processive movement of vesicles over long distances in axons.
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Huntingtin's function in axonal transport is conserved in Drosophila melanogaster. PLoS One 2013; 8:e60162. [PMID: 23555909 PMCID: PMC3610688 DOI: 10.1371/journal.pone.0060162] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 02/19/2013] [Indexed: 12/16/2022] Open
Abstract
Huntington’s disease (HD) is a devastating dominantly inherited neurodegenerative disorder caused by an abnormal polyglutamine expansion in the N-terminal part of the huntingtin (HTT) protein. HTT is a large scaffold protein that interacts with more than a hundred proteins and is probably involved in several cellular functions. The mutation is dominant, and is thought to confer new and toxic functions to the protein. However, there is emerging evidence that the mutation also alters HTT’s normal functions. Therefore, HD models need to recapitulate this duality if they are to be relevant. Drosophila melanogaster is a useful in vivo model, widely used to study HD through the overexpression of full-length or N-terminal fragments of mutant human HTT. However, it is unclear whether Drosophila huntingtin (DmHTT) shares functions similar to the mammalian HTT. Here, we used various complementary approaches to analyze the function of DmHTT in fast axonal transport. We show that DmHTT interacts with the molecular motor dynein, associates with vesicles and co-sediments with microtubules. DmHTT co-localizes with Brain-derived neurotrophic factor (BDNF)-containing vesicles in rat cortical neurons and partially replaces mammalian HTT in a fast axonal transport assay. DmHTT-KO flies show a reduced fast axonal transport of synaptotagmin vesicles in motoneurons in vivo. These results suggest that the function of HTT in axonal transport is conserved between flies and mammals. Our study therefore validates Drosophila melanogaster as a model to study HTT function, and its dysfunction associated with HD.
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van Spronsen M, Mikhaylova M, Lipka J, Schlager M, van den Heuvel D, Kuijpers M, Wulf P, Keijzer N, Demmers J, Kapitein L, Jaarsma D, Gerritsen H, Akhmanova A, Hoogenraad C. TRAK/Milton Motor-Adaptor Proteins Steer Mitochondrial Trafficking to Axons and Dendrites. Neuron 2013; 77:485-502. [DOI: 10.1016/j.neuron.2012.11.027] [Citation(s) in RCA: 283] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2012] [Indexed: 11/28/2022]
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Goodwin PR, Juo P. The scaffolding protein SYD-2/Liprin-α regulates the mobility and polarized distribution of dense-core vesicles in C. elegans motor neurons. PLoS One 2013; 8:e54763. [PMID: 23358451 PMCID: PMC3554613 DOI: 10.1371/journal.pone.0054763] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 12/14/2012] [Indexed: 01/05/2023] Open
Abstract
The polarized trafficking of axonal and dendritic components is essential for the development and maintenance of neuronal structure and function. Neuropeptide-containing dense-core (DCVs) vesicles are trafficked in a polarized manner from the cell body to their sites of release; however, the molecules involved in this process are not well defined. Here we show that the scaffolding protein SYD-2/Liprin-α is required for the normal polarized localization of Venus-tagged neuropeptides to axons of cholinergic motor neurons in C. elegans. In syd-2 loss of function mutants, the normal polarized localization of INS-22 neuropeptide-containing DCVs in motor neurons is disrupted, and DCVs accumulate in the cell body and dendrites. Time-lapse microscopy and kymograph analysis of mobile DCVs revealed that syd-2 mutants exhibit decreased numbers of DCVs moving in both anterograde and retrograde directions, and a corresponding increase in stationary DCVs in both axon commissures and dendrites. In addition, DCV run lengths and velocities were decreased in both axon commissures and dendrites of syd-2 mutants. This study shows that SYD-2 promotes bi-directional mobility of DCVs and identifies SYD-2 as a novel regulator of DCV trafficking and polarized distribution.
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Affiliation(s)
- Patricia R. Goodwin
- Department of Molecular Physiology and Pharmacology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Graduate Program in Neuroscience, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Peter Juo
- Department of Molecular Physiology and Pharmacology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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Petoukhov E, Fernando S, Mills F, Shivji F, Hunter D, Krieger C, Silverman MA, Bamji SX. Activity-dependent secretion of progranulin from synapses. J Cell Sci 2013; 126:5412-21. [DOI: 10.1242/jcs.132076] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The secreted growth factor progranulin (PGRN) has been shown to be important for regulating neuronal survival and outgrowth, as well as synapse formation and function. Mutations in the PGRN gene that result in PGRN haploinsufficiency have been identified as a major cause of frontotemporal dementia (FTD). Here we demonstrate that PGRN is colocalized with dense-core vesicle markers and is co-transported with brain-derived neurotrophic factor (BDNF) within axons and dendrites of cultured hippocampal neurons in both anterograde and retrograde directions. We also show that PGRN is secreted in an activity-dependent manner from synaptic and extrasynaptic sites, and that the temporal profiles of secretion are distinct in axons and dendrites. Neuronal activity is also shown to increase the recruitment of PGRN to synapses and to enhance the density of PGRN clusters along axons. Finally, treatment of neurons with recombinant PGRN is shown to increase synapse density, while decreasing the size of the presynaptic compartment and specifically the number of synaptic vesicles per synapse. Together, this indicates that activity-dependent secretion of PGRN can regulate synapse number and structure.
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Dynein mediates the localization and activation of mTOR in normal and human cytomegalovirus-infected cells. Genes Dev 2012; 26:2015-26. [PMID: 22987636 DOI: 10.1101/gad.196147.112] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Activation of stress signaling pathways normally leads to inhibition of the mammalian target of rapamycin complex 1 (mTORC1); however, human cytomegalovirus (HCMV) infection maintains mTORC1 activity in the presence of numerous types of stress. We previously demonstrated that HCMV infection maintains mTORC1 activity during amino acid deprivation through a Ras-related GTP-binding (Rag) protein-independent mechanism. This depends on the colocalization of mTOR and its activator, Rheb (Ras homology enriched in brain)-GTP, to a perinuclear position that corresponds to the viral cytoplasmic assembly compartment (AC). The data presented here show that the HCMV-induced, amino acid depletion-resistant perinuclear localization and activation of mTORC1 occurs as early as 8 h post-infection, prior to AC formation. We show that the molecular motor dynein is required for perinuclear localization of mTORC1 in both uninfected and HCMV-infected cells. Association between dynein and mTOR is shown by coimmunoprecipitation, and inhibition of dynein function using RNAi or the small molecule inhibitor ciliobrevin A inhibits mTORC1 activity in both uninfected and HCMV-infected cells. The data suggest that mTORC1 activation requires dynein-dependent transport to a position in the cell where it can be activated. Thus, the HCMV commandeers a cellular dynein-dependent mTORC1 activation mechanism to maintain stress-resistant mTORC1 activity during infection and to form the AC.
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47
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Cyclin-dependent kinase 5 regulates the polarized trafficking of neuropeptide-containing dense-core vesicles in Caenorhabditis elegans motor neurons. J Neurosci 2012; 32:8158-72. [PMID: 22699897 DOI: 10.1523/jneurosci.0251-12.2012] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The polarized trafficking of axonal and dendritic proteins is essential for the structure and function of neurons. Cyclin-dependent kinase 5 (CDK-5) and its activator CDKA-1/p35 regulate diverse aspects of nervous system development and function. Here, we show that CDK-5 and CDKA-1/p35 are required for the polarized distribution of neuropeptide-containing dense-core vesicles (DCVs) in Caenorhabditis elegans cholinergic motor neurons. In cdk-5 or cdka-1/p35 mutants, the predominantly axonal localization of DCVs containing INS-22 neuropeptides was disrupted and DCVs accumulated in dendrites. Time-lapse microscopy in DB class motor neurons revealed decreased trafficking of DCVs in axons and increased trafficking and accumulation of DCVs in cdk-5 mutant dendrites. The polarized distribution of several axonal and dendritic markers, including synaptic vesicles, was unaltered in cdk-5 mutant DB neurons. We found that microtubule polarity is plus-end out in axons and predominantly minus-end out in dendrites of DB neurons. Surprisingly, cdk-5 mutants had increased amounts of plus-end-out microtubules in dendrites, suggesting that CDK-5 regulates microtubule orientation. However, these changes in microtubule polarity are not responsible for the increased trafficking of DCVs into dendrites. Genetic analysis of cdk-5 and the plus-end-directed axonal DCV motor unc-104/KIF1A suggest that increased trafficking of UNC-104 into dendrites cannot explain the dendritic DCV accumulation. Instead, we found that mutations in the minus-end-directed motor cytoplasmic dynein, completely block the increased DCVs observed in cdk-5 mutant dendrites without affecting microtubule polarity. We propose a model in which CDK-5 regulates DCV polarity by both promoting DCV trafficking in axons and preventing dynein-dependent DCV trafficking into dendrites.
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48
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Bomfim TR, Forny-Germano L, Sathler LB, Brito-Moreira J, Houzel JC, Decker H, Silverman MA, Kazi H, Melo HM, McClean PL, Holscher C, Arnold SE, Talbot K, Klein WL, Munoz DP, Ferreira ST, De Felice FG. An anti-diabetes agent protects the mouse brain from defective insulin signaling caused by Alzheimer's disease- associated Aβ oligomers. J Clin Invest 2012; 122:1339-53. [PMID: 22476196 DOI: 10.1172/jci57256] [Citation(s) in RCA: 636] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Accepted: 01/05/2012] [Indexed: 02/06/2023] Open
Abstract
Defective brain insulin signaling has been suggested to contribute to the cognitive deficits in patients with Alzheimer's disease (AD). Although a connection between AD and diabetes has been suggested, a major unknown is the mechanism(s) by which insulin resistance in the brain arises in individuals with AD. Here, we show that serine phosphorylation of IRS-1 (IRS-1pSer) is common to both diseases. Brain tissue from humans with AD had elevated levels of IRS-1pSer and activated JNK, analogous to what occurs in peripheral tissue in patients with diabetes. We found that amyloid-β peptide (Aβ) oligomers, synaptotoxins that accumulate in the brains of AD patients, activated the JNK/TNF-α pathway, induced IRS-1 phosphorylation at multiple serine residues, and inhibited physiological IRS-1pTyr in mature cultured hippocampal neurons. Impaired IRS-1 signaling was also present in the hippocampi of Tg mice with a brain condition that models AD. Importantly, intracerebroventricular injection of Aβ oligomers triggered hippocampal IRS-1pSer and JNK activation in cynomolgus monkeys. The oligomer-induced neuronal pathologies observed in vitro, including impaired axonal transport, were prevented by exposure to exendin-4 (exenatide), an anti-diabetes agent. In Tg mice, exendin-4 decreased levels of hippocampal IRS-1pSer and activated JNK and improved behavioral measures of cognition. By establishing molecular links between the dysregulated insulin signaling in AD and diabetes, our results open avenues for the investigation of new therapeutics in AD.
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Affiliation(s)
- Theresa R Bomfim
- Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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Scalettar BA, Jacobs C, Fulwiler A, Prahl L, Simon A, Hilken L, Lochner JE. Hindered submicron mobility and long-term storage of presynaptic dense-core granules revealed by single-particle tracking. Dev Neurobiol 2012; 72:1181-95. [PMID: 21976424 DOI: 10.1002/dneu.20984] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 09/26/2011] [Accepted: 09/27/2011] [Indexed: 01/29/2023]
Abstract
Dense-core granules (DCGs) are organelles found in neuroendocrine cells and neurons that house, transport, and release a number of important peptides and proteins. In neurons, DCG cargo can include the secreted neuromodulatory proteins tissue plasminogen activator (tPA) and/or brain-derived neurotrophic factor (BDNF), which play a key role in modulating synaptic efficacy in the hippocampus. This function has spurred interest in DCGs that localize to synaptic contacts between hippocampal neurons, and several studies recently have established that DCGs localize to, and undergo regulated exocytosis from, postsynaptic sites. To complement this work, we have studied presynaptically localized DCGs in hippocampal neurons, which are much more poorly understood than their postsynaptic analogs. Moreover, to enhance relevance, we visualized DCGs via fluorescence labeling of exogenous and endogenous tPA and BDNF. Using single-particle tracking, we determined trajectories of more than 150 presynaptically localized DCGs. These trajectories reveal that mobility of DCGs in presynaptic boutons is highly hindered and that storage is long-lived. We also computed mean-squared displacement curves, which can be used to elucidate mechanisms of transport. Over shorter time windows, most curves are linear, demonstrating that DCG transport in boutons is driven predominantly by diffusion. The remaining curves plateau with time, consistent with motion constrained by a submicron-sized corral. These results have relevance to recent models of presynaptic organization and to recent hypotheses about DCG cargo function. The results also provide estimates for transit times to the presynaptic plasma membrane that are consistent with measured times for onset of neurotrophin release from synaptically localized DCGs.
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Affiliation(s)
- B A Scalettar
- Department of Physics, Lewis and Clark College, Portland, Oregon 97219, USA
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Abstract
The equal distribution of synaptic vesicles among synapses along the axon is critical for robust neurotransmission. Wong et al. show that the continuous circulation of synaptic vesicles throughout the axon driven by molecular motors ultimately yields this even distribution.
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Affiliation(s)
- Armen J Moughamian
- Department of Physiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104-6085, USA
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