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Odell LR, Jones NC, Chau N, Robertson MJ, Ambrus JI, Deane FM, Young KA, Whiting A, Xue J, Prichard K, Daniel JA, Gorgani NN, O'Brien TJ, Robinson PJ, McCluskey A. The sulfonadyns: a class of aryl sulfonamides inhibiting dynamin I GTPase and clathrin mediated endocytosis are anti-seizure in animal models. RSC Med Chem 2023; 14:1492-1511. [PMID: 37593570 PMCID: PMC10429932 DOI: 10.1039/d2md00371f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 04/15/2023] [Indexed: 08/19/2023] Open
Abstract
We show that dansylcadaverine (1) a known in-cell inhibitor of clathrin mediated endocytosis (CME), moderately inhibits dynamin I (dynI) GTPase activity (IC50 45 μM) and transferrin (Tfn) endocytosis in U2OS cells (IC50 205 μM). Synthesis gave a new class of GTP-competitive dynamin inhibitors, the Sulfonadyns™. The introduction of a terminal cinnamyl moiety greatly enhanced dynI inhibition. Rigid diamine or amide links between the dansyl and cinnamyl moieties were detrimental to dynI inhibition. Compounds with in vitro inhibition of dynI activity <10 μM were tested in-cell for inhibition of CME. These data unveiled a number of compounds, e.g. analogues 33 ((E)-N-(6-{[(3-(4-bromophenyl)-2-propen-1-yl]amino}hexyl)-5-isoquinolinesulfonamide)) and 47 ((E)-N-(3-{[3-(4-bromophenyl)-2-propen-1-yl]amino}propyl)-1-naphthalenesulfonamide)isomers that showed dyn IC50 <4 μM, IC50(CME) <30 μM and IC50(SVE) from 12-265 μM. Both analogues (33 and 47) are at least 10 times more potent that the initial lead, dansylcadaverine (1). Enzyme kinetics revealed these sulfonamide analogues as being GTP competitive inhibitors of dynI. Sulfonadyn-47, the most potent SVE inhibitor observed (IC50(SVE) = 12.3 μM), significantly increased seizure threshold in a 6 Hz mouse psychomotor seizure test at 30 (p = 0.003) and 100 mg kg-1 ip (p < 0.0001), with similar anti-seizure efficacy to the established anti-seizure medication, sodium valproate (400 mg kg-1). The Sulfonadyn™ class of drugs target dynamin and show promise as novel leads for future anti-seizure medications.
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Affiliation(s)
- Luke R Odell
- Chemistry, Centre for Chemical Biology, School of Environmental & Life Science, The University of Newcastle University Drive Callaghan NSW 2308 Australia +612 4921 5472 +612 4921 6486
| | - Nigel C Jones
- Department of Neuroscience, Central Clinical School, Monash University Melbourne Victoria 3004 Australia
- Department of Neurology, The Alfred Hospital Commercial Road Melbourne Victoria 3004 Australia
- Department of Medicine (Royal Melbourne Hospital), University of Melbourne Parkville Victoria 3052 Australia
| | - Ngoc Chau
- Cell Signaling Unit, Children's Medical Research Institute, The University of Sydney 214 Hawkesbury Road Westmead NSW 2145 Australia +612 8865 2915
| | - Mark J Robertson
- Chemistry, Centre for Chemical Biology, School of Environmental & Life Science, The University of Newcastle University Drive Callaghan NSW 2308 Australia +612 4921 5472 +612 4921 6486
| | - Joseph I Ambrus
- Chemistry, Centre for Chemical Biology, School of Environmental & Life Science, The University of Newcastle University Drive Callaghan NSW 2308 Australia +612 4921 5472 +612 4921 6486
| | - Fiona M Deane
- Chemistry, Centre for Chemical Biology, School of Environmental & Life Science, The University of Newcastle University Drive Callaghan NSW 2308 Australia +612 4921 5472 +612 4921 6486
| | - Kelly A Young
- Chemistry, Centre for Chemical Biology, School of Environmental & Life Science, The University of Newcastle University Drive Callaghan NSW 2308 Australia +612 4921 5472 +612 4921 6486
| | - Ainslie Whiting
- Cell Signaling Unit, Children's Medical Research Institute, The University of Sydney 214 Hawkesbury Road Westmead NSW 2145 Australia +612 8865 2915
| | - Jing Xue
- Cell Signaling Unit, Children's Medical Research Institute, The University of Sydney 214 Hawkesbury Road Westmead NSW 2145 Australia +612 8865 2915
| | - Kate Prichard
- Chemistry, Centre for Chemical Biology, School of Environmental & Life Science, The University of Newcastle University Drive Callaghan NSW 2308 Australia +612 4921 5472 +612 4921 6486
| | - James A Daniel
- Cell Signaling Unit, Children's Medical Research Institute, The University of Sydney 214 Hawkesbury Road Westmead NSW 2145 Australia +612 8865 2915
| | - Nick N Gorgani
- Cell Signaling Unit, Children's Medical Research Institute, The University of Sydney 214 Hawkesbury Road Westmead NSW 2145 Australia +612 8865 2915
| | - Terence J O'Brien
- Department of Neurology, The Alfred Hospital Commercial Road Melbourne Victoria 3004 Australia
- Department of Medicine (Royal Melbourne Hospital), University of Melbourne Parkville Victoria 3052 Australia
| | - Phillip J Robinson
- Cell Signaling Unit, Children's Medical Research Institute, The University of Sydney 214 Hawkesbury Road Westmead NSW 2145 Australia +612 8865 2915
| | - Adam McCluskey
- Chemistry, Centre for Chemical Biology, School of Environmental & Life Science, The University of Newcastle University Drive Callaghan NSW 2308 Australia +612 4921 5472 +612 4921 6486
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Alkafaas SS, Abdallah AM, Ghosh S, Loutfy SA, Elkafas SS, Abdel Fattah NF, Hessien M. Insight into the role of clathrin-mediated endocytosis inhibitors in SARS-CoV-2 infection. Rev Med Virol 2023; 33:e2403. [PMID: 36345157 PMCID: PMC9877911 DOI: 10.1002/rmv.2403] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 10/08/2022] [Accepted: 10/10/2022] [Indexed: 11/10/2022]
Abstract
Emergence of SARS-CoV-2 variants warrants sustainable efforts to upgrade both the diagnostic and therapeutic protocols. Understanding the details of cellular and molecular basis of the virus-host cell interaction is essential for developing variant-independent therapeutic options. The internalization of SARS-CoV-2, into lung epithelial cells, is mediated by endocytosis, especially clathrin-mediated endocytosis (CME). Although vaccination is the gold standard strategy against viral infection, selective inhibition of endocytic proteins, complexes, and associated adaptor proteins may present a variant-independent therapeutic strategy. Although clathrin and/or dynamins are the most important proteins involved in CME, other endocytic mechanisms are clathrin and/or dynamin independent and rely on other proteins. Moreover, endocytosis implicates some subcellular structures, like plasma membrane, actin and lysosomes. Also, physiological conditions, such as pH and ion concentrations, represent an additional factor that mediates these events. Accordingly, endocytosis related proteins are potential targets for small molecules that inhibit endocytosis-mediated viral entry. This review summarizes the potential of using small molecules, targeting key proteins, participating in clathrin-dependent and -independent endocytosis, as variant-independent antiviral drugs against SARS-CoV-2 infection. The review takes two approaches. The first outlines the potential role of endocytic inhibitors in preventing endocytosis-mediated viral entry and its mechanism of action, whereas in the second computational analysis was implemented to investigate the selectivity of common inhibitors against endocytic proteins in SARS-CoV-2 endocytosis. The analysis revealed that remdesivir, methyl-β-cyclodextrin, rottlerin, and Bis-T can effectively inhibit clathrin, HMG-CoA reductase, actin, and dynamin I GTPase and are more potent in inhibiting SARS-CoV-2 than chloroquine. CME inhibitors for SARS-CoV-2 infection remain understudied.
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Affiliation(s)
- Samar Sami Alkafaas
- Molecular Cell Biology UniteDivision of BiochemistryDepartment of ChemistryFaculty of ScienceTanta UniversityTantaEgypt
| | - Abanoub Mosaad Abdallah
- Narcotic Research DepartmentNational Center for Social and Criminological Research (NCSCR)GizaEgypt
| | - Soumya Ghosh
- Department of GeneticsFaculty of Natural and Agricultural SciencesUniversity of the Free StateBloemfonteinSouth Africa
| | - Samah A. Loutfy
- Virology and Immunology UnitCancer Biology DepartmentNational Cancer Institute (NCI)Cairo UniversityCairoEgypt
- Nanotechnology Research CenterBritish UniversityCairoEgypt
| | - Sara Samy Elkafas
- Production Engineering and Mechanical Design DepartmentFaculty of EngineeringMenofia UniversityMenofiaEgypt
| | - Nasra F. Abdel Fattah
- Virology and Immunology UnitCancer Biology DepartmentNational Cancer Institute (NCI)Cairo UniversityCairoEgypt
| | - Mohamed Hessien
- Molecular Cell Biology UniteDivision of BiochemistryDepartment of ChemistryFaculty of ScienceTanta UniversityTantaEgypt
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Sheridan SD, Horng JE, Perlis RH. Patient-Derived In Vitro Models of Microglial Function and Synaptic Engulfment in Schizophrenia. Biol Psychiatry 2022; 92:470-479. [PMID: 35232567 PMCID: PMC10039432 DOI: 10.1016/j.biopsych.2022.01.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 12/19/2021] [Accepted: 01/10/2022] [Indexed: 01/11/2023]
Abstract
Multiple lines of evidence implicate dysregulated microglia-mediated synaptic pruning in the pathophysiology of schizophrenia. In vitro human cellular studies represent a promising means of pursuing this hypothesis, complementing efforts with animal models and postmortem human data while addressing their limitations. The challenges in culturing homogeneous populations of cells derived from postmortem or surgical biopsy brain material from patients, and their limited availability, has led to a focus on differentiation of induced pluripotent stem cells. These methods too have limitations, in that they disrupt the epigenome and can demonstrate line-to-line variability due in part to extended time in culture, partial reprogramming, and/or residual epigenetic memory from the cell source, yielding large technical artifacts. Yet another strategy uses direct transdifferentiation of peripheral mononuclear blood cells, or umbilical cord blood cells, to microglia-like cells. Any of these approaches can be paired with patient-derived synaptosomes from differentiated neurons as a simpler alternative to co-culture. Patient-derived microglia models may facilitate identification of novel modulators of synaptic pruning and identification of biomarkers that may allow more targeted early interventions.
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Affiliation(s)
- Steven D Sheridan
- Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts; Department of Psychiatry, Harvard Medical School, Boston, Massachusetts
| | - Joy E Horng
- Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts; Department of Psychiatry, Harvard Medical School, Boston, Massachusetts
| | - Roy H Perlis
- Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts; Department of Psychiatry, Harvard Medical School, Boston, Massachusetts.
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Geda O, Tábi T, Lakatos PP, Szökő É. Differential Ganglioside and Cholesterol Depletion by Various Cyclodextrin Derivatives and Their Effect on Synaptosomal Glutamate Release. Int J Mol Sci 2022; 23:ijms23169460. [PMID: 36012724 PMCID: PMC9409351 DOI: 10.3390/ijms23169460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/10/2022] [Accepted: 08/19/2022] [Indexed: 11/16/2022] Open
Abstract
Gangliosides are glycosphingolipids of the plasma membrane and are highly enriched in the nervous system where they play a vital role in normal cell functions. Furthermore, several studies suggest their potential involvement in the pathogenesis of neurological conditions. Since cyclodextrins (CDs) can form inclusion complexes with various lipids, methylated beta-CDs are widely used in biomedical research to extract cholesterol from the membrane and study its cellular role. Despite CDs being known to interact with other membrane lipid components, their effect on gangliosides is poorly characterized. The aim of this research was to investigate the effect of dimethyl-beta-cyclodextrin (DIMEB), hydroxypropyl-beta-cyclodextrin (HPBCD), randomly methylated-alpha-cyclodextrin (RAMEA), and hydroxypropyl-alpha-cyclodextrin (HPACD) on ganglioside and cholesterol levels in rat brain synaptosomes. Their effect on membrane integrity and viability was also assessed. We examined the role of lipid depletion by CDs on the release of the major excitatory neurotransmitter, glutamate. Selective concentration range for cholesterol depletion was only found with HPBCD, but not with DIMEB. Selective depletion of gangliosides was achieved by both RAMEA and HPACD. The inhibition of stimulated glutamate release upon ganglioside depletion was found, suggesting their potential role in neurotransmission. Our study highlights the importance of the characterization of the lipid depleting capability of different CDs.
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Svirsky SE, Ranellone NS, Parry M, Holets E, Henchir J, Li Y, Carlson SW, Edward Dixon C. All-trans Retinoic Acid has Limited Therapeutic Effects on Cognition and Hippocampal Protein Expression After Controlled Cortical Impact. Neuroscience 2022; 499:130-141. [PMID: 35878718 DOI: 10.1016/j.neuroscience.2022.07.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 10/17/2022]
Abstract
Traumatic brain injury (TBI) is known to impair synaptic function, and subsequently contribute to observed cognitive deficits. Retinoic Acid (RA) signaling modulates expression of synaptic plasticity proteins and is involved in hippocampal learning and memory. All trans-retinoic acid (ATRA), a metabolite of Vitamin A, has been identified as a potential pharmacotherapeutic for other neurological disorders due to this role. This study conducted an ATRA dose response to determine its therapeutic effects on cognitive behaviors and expression of hippocampal markers of synaptic plasticity and RA signaling proteins after experimental TBI. Under isoflurane anesthesia, adult male Sprague Dawley rats received either controlled cortical impact (CCI, 2.5 mm deformation, 4 m/s) or control surgery. Animals received daily intraperitoneal injection of 0.5, 1, 5, or 10 mg/kg of ATRA or vehicle for 2 weeks. Animals underwent motor and spatial learning and memory testing. Hippocampal expression of synaptic plasticity proteins neurogranin (Ng), and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor GluA1 sub-unit, as well as RA signaling proteins STRA6, ADLH1a1, CYP26A1 and CYP26B1 were evaluated by western blot at 2-weeks post-injury. ATRA treatment significantly recovered Ng synaptic protein expression, while having no effect on motor performance, spatial learning, and memory, and GluA1 expression after TBI. RA signaling protein expression is unchanged 2 weeks after TBI. Overall, ATRA administration after TBI showed limited therapeutic benefits compared to the vehicle.
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Affiliation(s)
- Sarah E Svirsky
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA; Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
| | - Nicholas S Ranellone
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
| | - Madison Parry
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
| | - Erik Holets
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
| | - Jeremy Henchir
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
| | - Youming Li
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
| | - Shaun W Carlson
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
| | - C Edward Dixon
- Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA; Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA; V.A. Pittsburgh Healthcare System, Pittsburgh, Pennsylvania, USA.
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Prichard KL, O'Brien NS, Murcia SR, Baker JR, McCluskey A. Role of Clathrin and Dynamin in Clathrin Mediated Endocytosis/Synaptic Vesicle Recycling and Implications in Neurological Diseases. Front Cell Neurosci 2022; 15:754110. [PMID: 35115907 PMCID: PMC8805674 DOI: 10.3389/fncel.2021.754110] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 12/10/2021] [Indexed: 12/17/2022] Open
Abstract
Endocytosis is a process essential to the health and well-being of cell. It is required for the internalisation and sorting of “cargo”—the macromolecules, proteins, receptors and lipids of cell signalling. Clathrin mediated endocytosis (CME) is one of the key processes required for cellular well-being and signalling pathway activation. CME is key role to the recycling of synaptic vesicles [synaptic vesicle recycling (SVR)] in the brain, it is pivotal to signalling across synapses enabling intracellular communication in the sensory and nervous systems. In this review we provide an overview of the general process of CME with a particular focus on two key proteins: clathrin and dynamin that have a central role to play in ensuing successful completion of CME. We examine these two proteins as they are the two endocytotic proteins for which small molecule inhibitors, often of known mechanism of action, have been identified. Inhibition of CME offers the potential to develop therapeutic interventions into conditions involving defects in CME. This review will discuss the roles and the current scope of inhibitors of clathrin and dynamin, providing an insight into how further developments could affect neurological disease treatments.
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Štimac I, Jug Vučko N, Blagojević Zagorac G, Marcelić M, Mahmutefendić Lučin H, Lučin P. Dynamin Inhibitors Prevent the Establishment of the Cytomegalovirus Assembly Compartment in the Early Phase of Infection. Life (Basel) 2021; 11:life11090876. [PMID: 34575026 PMCID: PMC8469281 DOI: 10.3390/life11090876] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/21/2021] [Accepted: 08/23/2021] [Indexed: 12/30/2022] Open
Abstract
Cytomegalovirus (CMV) infection initiates massive rearrangement of cytoplasmic organelles to generate assembly compartment (AC). The earliest events, the establishment of the preAC, are initiated in the early phase as an extensive reorganization of early endosomes (EEs), endosomal recycling compartment (ERC), trans-Golgi network (TGN), and the Golgi. Here, we demonstrate that dynamin inhibitors (Dynasore, Dyngo-4a, MiTMAB, and Dynole-34-2) block the establishment of the preAC in murine CMV (MCMV) infected cells. In this study, we extensively analyzed the effect of Dynasore on the Golgi reorganization sequence into the outer preAC. We also monitored the development of the inner preAC using a set of markers that define EEs (Rab5, Vps34, EEA1, and Hrs), the EE-ERC interface (Rab10), the ERC (Rab11, Arf6), three layers of the Golgi (GRASP65, GM130, Golgin97), and late endosomes (Lamp1). Dynasore inhibited the pericentriolar accumulation of all markers that display EE-ERC-TGN interface in the inner preAC and prevented Golgi unlinking and dislocation to the outer preAC. Furthermore, in pulse-chase experiments, we demonstrated that the presence of dynasore only during the early phase of MCMV infection (4-14 hpi) is sufficient to prevent not only AC formation but also the synthesis of late-phase proteins and virion production. Therefore, our results indicate that dynamin-2 acts as a part of the machinery required for AC generation and rearrangement of EE/ERC/Golgi membranes in the early phase of CMV infection.
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Affiliation(s)
- Igor Štimac
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (I.Š.); (N.J.V.); (G.B.Z.); (M.M.); (P.L.)
| | - Natalia Jug Vučko
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (I.Š.); (N.J.V.); (G.B.Z.); (M.M.); (P.L.)
| | - Gordana Blagojević Zagorac
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (I.Š.); (N.J.V.); (G.B.Z.); (M.M.); (P.L.)
- Nursing Department, University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
| | - Marina Marcelić
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (I.Š.); (N.J.V.); (G.B.Z.); (M.M.); (P.L.)
| | - Hana Mahmutefendić Lučin
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (I.Š.); (N.J.V.); (G.B.Z.); (M.M.); (P.L.)
- Nursing Department, University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
- Correspondence:
| | - Pero Lučin
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (I.Š.); (N.J.V.); (G.B.Z.); (M.M.); (P.L.)
- Nursing Department, University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
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Boll I, Jensen P, Schwämmle V, Larsen MR. Depolarization-dependent Induction of Site-specific Changes in Sialylation on N-linked Glycoproteins in Rat Nerve Terminals. Mol Cell Proteomics 2020; 19:1418-1435. [PMID: 32518069 PMCID: PMC8143646 DOI: 10.1074/mcp.ra119.001896] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 06/08/2020] [Indexed: 12/11/2022] Open
Abstract
Synaptic transmission leading to release of neurotransmitters in the nervous system is a fast and highly dynamic process. Previously, protein interaction and phosphorylation have been thought to be the main regulators of synaptic transmission. Here we show that sialylation of N-linked glycosylation is a novel potential modulator of neurotransmitter release mechanisms by investigating depolarization-dependent changes of formerly sialylated N-linked glycopeptides. We suggest that negatively charged sialic acids can be modulated, similarly to phosphorylation, by the action of sialyltransferases and sialidases thereby changing local structure and function of membrane glycoproteins. We characterized site-specific alteration in sialylation on N-linked glycoproteins in isolated rat nerve terminals after brief depolarization using quantitative sialiomics. We identified 1965 formerly sialylated N-linked glycosites in synaptic proteins and found that the abundances of 430 glycosites changed after 5 s depolarization. We observed changes on essential synaptic proteins such as synaptic vesicle proteins, ion channels and transporters, neurotransmitter receptors and cell adhesion molecules. This study is to our knowledge the first to describe ultra-fast site-specific modulation of the sialiome after brief stimulation of a biological system.
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Affiliation(s)
- Inga Boll
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Pia Jensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Veit Schwämmle
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark
| | - Martin R Larsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense M, Denmark.
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Song C, Zhou H, Lu H, Luo C, Wang C, Wang Q, Peng Y, Xin Y, Liu T, Yang W. Aberrant expression for microRNA is potential crucial factors of haemorrhoid. Hereditas 2020; 157:25. [PMID: 32620169 PMCID: PMC7334851 DOI: 10.1186/s41065-020-00139-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 06/30/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Haemorrhoids occur commonly and frequently in the human digestive system. There are diverse causes of haemorrhoids and their in-depth pathogenesis is still currently unclear. METHODS In this study, we explored haemorrhoids from an epigenetics perspective by employing RNA-Seq for comprehensive and in-depth analysis of the differences in microRNA (miRNA) transcripts between haemorrhoidal tissue and normal tissue in 48 patients with Grade II and above haemorrhoids. RESULTS The results showed that 9 miRNAs were significantly upregulated (ratio > 3.5 and P-value < 0.01) and 16 miRNAs were significantly downregulated (ratio > 0.6 and P-value < 0.01) in haemorrhoid tissue. Subsequently, target gene prediction results showed that there were 184 potential target genes of significantly upregulated miRNAs (common to both TargetScan7.1 and MirdbV5 databases) and there were 372 potential target genes of significantly downregulated miRNAs. Gene ontology analysis results showed that the target genes of differentially expressed miRNAs in haemorrhoids are involved in regulating "cell composition" and "protein binding". Lastly, KEGG search found that the differentially expressed miRNAs that are associated with the occurrence of haemorrhoids mainly regulate the activity of endocytosis and the synaptic vesicle cycle. CONCLUSIONS In summary, the results of high-throughput RNA-Seq screening suggested that the occurrence of haemorrhoids may be intimately associated with aberrant miRNA transcription, resulting in aberrant target gene expression and an imbalance in certain signal transduction pathways.
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Affiliation(s)
- Chengkun Song
- Department of Anorectal Surgery, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, 528 Zhangheng Road, Shanghai, 201203, P.R. China
| | - Haikun Zhou
- Department of Anorectal Surgery, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, 528 Zhangheng Road, Shanghai, 201203, P.R. China
| | - Hong Lu
- Department of Anorectal Surgery, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, 528 Zhangheng Road, Shanghai, 201203, P.R. China
| | - Chunsheng Luo
- Department of Anorectal Surgery, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, 528 Zhangheng Road, Shanghai, 201203, P.R. China
| | - Chen Wang
- Department of Anorectal Surgery, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, 528 Zhangheng Road, Shanghai, 201203, P.R. China
| | - Qingming Wang
- Department of Anorectal Surgery, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, 528 Zhangheng Road, Shanghai, 201203, P.R. China
| | - Yunhua Peng
- Department of Anorectal Surgery, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, 528 Zhangheng Road, Shanghai, 201203, P.R. China
| | - Yaojie Xin
- Department of Otolaryngology, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Te Liu
- Shanghai Geriatric Institute of Chinese Medicine, Shanghai University of Traditional Chinese Medicine, 365 South Xiangyang Road, Shanghai, 200031, P.R. China. .,Department of Pathology, Yale University School of Medicine, New Haven, CT, 06520, USA.
| | - Wei Yang
- Department of Anorectal Surgery, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, 528 Zhangheng Road, Shanghai, 201203, P.R. China.
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Liu C, Huang Z, Jiang W, Liu X, Li J, Han X, Tu H, Qiu L, Tan W. Programmable pH-Responsive DNA Nanosensors for Imaging Exocytosis and Retrieval of Synaptic Vesicles. Anal Chem 2020; 92:3620-3626. [DOI: 10.1021/acs.analchem.9b04493] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chao Liu
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Zike Huang
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Wei Jiang
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Xiaojing Liu
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Jin Li
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, P. R. China
- Institute of Cancer and Basic Medicine (IBMC), Chinese Academy of Sciences, The Cancer Hospital of the University of Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, P. R. China
| | - Xiaoyan Han
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Haijun Tu
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Liping Qiu
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, P. R. China
| | - Weihong Tan
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, P. R. China
- Institute of Molecular Medicine (IMM), Renji Hospital, State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, and College of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
- Foundation for Applied Molecular Evolution, 13709 Progress Boulevard, Alachua, Florida 32615, United States
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11
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Positive surface charge of GluN1 N-terminus mediates the direct interaction with EphB2 and NMDAR mobility. Nat Commun 2020; 11:570. [PMID: 31996679 PMCID: PMC6989673 DOI: 10.1038/s41467-020-14345-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 12/19/2019] [Indexed: 12/31/2022] Open
Abstract
Localization of the N-methyl-D-aspartate type glutamate receptor (NMDAR) to dendritic spines is essential for excitatory synaptic transmission and plasticity. Rather than remaining trapped at synaptic sites, NMDA receptors undergo constant cycling into and out of the postsynaptic density. Receptor movement is constrained by protein-protein interactions with both the intracellular and extracellular domains of the NMDAR. The role of extracellular interactions on the mobility of the NMDAR is poorly understood. Here we demonstrate that the positive surface charge of the hinge region of the N-terminal domain in the GluN1 subunit of the NMDAR is required to maintain NMDARs at dendritic spine synapses and mediates the direct extracellular interaction with a negatively charged phospho-tyrosine on the receptor tyrosine kinase EphB2. Loss of the EphB-NMDAR interaction by either mutating GluN1 or knocking down endogenous EphB2 increases NMDAR mobility. These findings begin to define a mechanism for extracellular interactions mediated by charged domains.
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12
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Gharami K, Biswas SC. Glutamate treatment mimics LTP- and LTD-like biochemical activity in viable synaptosome preparation. Neurochem Int 2020; 134:104655. [PMID: 31899196 DOI: 10.1016/j.neuint.2019.104655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 12/05/2019] [Accepted: 12/29/2019] [Indexed: 01/28/2023]
Abstract
Long-term potentiation (LTP) and long-term depression (LTD) are considered to be the cellular mechanisms behind the increase or decrease of synaptic strength respectively. Electrophysiologically induced LTP/LTD is associated with the activation of glutamate receptors in the synaptic terminals resulting in the initiation of biochemical processes in the postsynaptic terminals and thus propagation of synaptic activity. Isolated nerve endings i.e. synaptosome preparation was used to study here, the biochemical phenotypes of LTP and LTD, and glutamate treatment in varying concentration for different time was used to induce those biochemical phenomena. Treatment with 200 μM glutamate showed increased GluA1 phosphorylation at serine 831 and activation of CaMKIIα by phosphorylation at threonine 286 like LTP, whereas 100 μM glutamate treatment showed decrease in GluA1 phosphorylation level at both pGluA1(S831) and pGluA1(S845), and activation of GSK3β by de-phosphorylating pGSK3β at serine 9 like LTD. The 200 μM glutamate treatment was associated with an increase in the local translation of Arc, BDNF, CaMKIIα and Homer1, whereas 100 μM glutamate treatments resulted in decrease in the level of the said synaptic proteins and the effect was blocked by the proteasomal inhibitor, Lactasystin. Both, the local translation and local degradation was sensitive to the Ca2+ chellator, Bapta-AM, indicating that both the phenomena were dependent on the rise in intra-synaptosomal Ca2+, like LTP and LTD. Overall the results of the present study suggest that synaptosomal preparations can be a viable alternative to study mechanisms underlying the biochemical activities of LTP/LTD in short term.
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Affiliation(s)
- Kusumika Gharami
- Cell Biology & Physiology Division, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata, 700032, India.
| | - Subhas C Biswas
- Cell Biology & Physiology Division, CSIR-Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Road, Jadavpur, Kolkata, 700032, India.
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13
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SIV-Mediated Synaptic Dysfunction Is Associated with an Increase in Synapsin Site 1 Phosphorylation and Impaired PP2A Activity. J Neurosci 2019; 39:7006-7018. [PMID: 31270156 DOI: 10.1523/jneurosci.0178-19.2019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 05/31/2019] [Accepted: 06/22/2019] [Indexed: 11/21/2022] Open
Abstract
Although the reduction of viral loads in people with HIV undergoing combination antiretroviral therapy has mitigated AIDS-related symptoms, the prevalence of neurological impairments has remained unchanged. HIV-associated CNS dysfunction includes impairments in memory, attention, memory processing, and retrieval. Here, we show a significant site-specific increase in the phosphorylation of Syn I serine 9, site 1, in the frontal cortex lysates and synaptosome preparations of male rhesus macaques infected with simian immunodeficiency virus (SIV) but not in uninfected or SIV-infected antiretroviral therapy animals. Furthermore, we found that a lower protein phosphatase 2A (PP2A) activity, a phosphatase responsible for Syn I (S9) dephosphorylation, is primarily associated with the higher S9 phosphorylation in the frontal cortex of SIV-infected macaques. Comparison of brain sections confirmed higher Syn I (S9) in the frontal cortex and greater coexpression of Syn I and PP2A A subunit, which was observed as perinuclear aggregates in the somata of the frontal cortex of SIV-infected macaques. Synaptosomes from SIV-infected animals were physiologically tested using a synaptic vesicle endocytosis assay and FM4-64 dye showing a significantly higher baseline depolarization levels in synaptosomes of SIV+-infected than uninfected control or antiretroviral therapy animals. A PP2A-activating FDA-approved drug, FTY720, decreased the higher synaptosome depolarization in SIV-infected animals. Our results suggest that an impaired distribution and lower activity of serine/threonine phosphatases in the context of HIV infection may cause an indirect effect on the phosphorylation levels of essential proteins involving in synaptic transmission, supporting the occurrence of specific impairments in the synaptic activity during SIV infection.SIGNIFICANCE STATEMENT Even with antiretroviral therapy, neurocognitive deficits, including impairments in attention, memory processing, and retrieval, are still major concerns in people living with HIV. Here, we used the rhesus macaque simian immunodeficiency virus model with and without antiretroviral therapy to study the dynamics of phosphorylation of key amino acid residues of synapsin I, which critically impacts synaptic vesicle function. We found a significant increase in synapsin I phosphorylation at serine 9, which was driven by dysfunction of serine/threonine protein phosphatase 2A in the nerve terminals. Our results suggest that an impaired distribution and lower activity of serine/threonine phosphatases in the context of HIV infection may cause an indirect effect on the phosphorylation levels of essential proteins involved in synaptic transmission.
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14
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Li X, Qin L, Li Y, Yu H, Zhang Z, Tao C, Liu Y, Xue Y, Zhang X, Xu Z, Wang Y, Lou H, Tan Z, Saftig P, Chen Z, Xu T, Bi G, Duan S, Gao Z. Presynaptic Endosomal Cathepsin D Regulates the Biogenesis of GABAergic Synaptic Vesicles. Cell Rep 2019; 28:1015-1028.e5. [DOI: 10.1016/j.celrep.2019.06.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 03/16/2019] [Accepted: 05/31/2019] [Indexed: 12/18/2022] Open
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15
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Critical Analysis of Particle Detection Artifacts in Synaptosome Flow Cytometry. eNeuro 2019; 6:ENEURO.0009-19.2019. [PMID: 31118205 PMCID: PMC6565374 DOI: 10.1523/eneuro.0009-19.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/01/2019] [Accepted: 04/27/2019] [Indexed: 11/21/2022] Open
Abstract
Flow cytometry and fluorescence-activated sorting are powerful techniques that hold great promise for studying heterogeneous populations of submicron particles such as synaptosomes, but many technical challenges arise in these experiments. To date, most flow cytometry studies of synaptosomes have relied on particle detection using forward scatter (FSC) measurements and size estimation with polystyrene (PS) bead standards. However, these practices have serious limitations, and special care must be taken to overcome the poor sensitivity of conventional flow cytometers in the analysis of submicron particles. Technical artifacts can confound these experiments, especially the detection of multiple particles as a single event. Here, we compared analysis of P2 crude synaptosomal preparations from murine forebrain on multiple flow cytometers using both FSC-triggered and fluorescence-triggered detection. We implemented multicolor fluorescent dye-based assays to quantify coincident particle detection and aggregation, and we assessed the false colocalization of antigens in immunostaining analyses. Our results demonstrate that fluorescence triggering and proper dilution can control for coincident particle detection, but not particle aggregation. We confirmed previous studies showing that FSC-based size estimation with PS beads underestimates biological particle size, and we identified pervasive aggregation in the FSC range analyzed in most synaptosome flow cytometry studies. We found that analyzing P2 samples in sucrose/EDTA/tris (SET) buffer reduces aggregation compared to PBS, but does not completely eliminate the presence of aggregates, especially in immunostaining experiments. Our study highlights challenges and pitfalls in synaptosome flow cytometry and provides a methodological framework for future studies.
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16
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Sellgren CM, Gracias J, Watmuff B, Biag JD, Thanos JM, Whittredge PB, Fu T, Worringer K, Brown HE, Wang J, Kaykas A, Karmacharya R, Goold CP, Sheridan SD, Perlis RH. Increased synapse elimination by microglia in schizophrenia patient-derived models of synaptic pruning. Nat Neurosci 2019; 22:374-385. [PMID: 30718903 DOI: 10.1038/s41593-018-0334-7] [Citation(s) in RCA: 424] [Impact Index Per Article: 84.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 12/19/2018] [Indexed: 12/11/2022]
Abstract
Synapse density is reduced in postmortem cortical tissue from schizophrenia patients, which is suggestive of increased synapse elimination. Using a reprogrammed in vitro model of microglia-mediated synapse engulfment, we demonstrate increased synapse elimination in patient-derived neural cultures and isolated synaptosomes. This excessive synaptic pruning reflects abnormalities in both microglia-like cells and synaptic structures. Further, we find that schizophrenia risk-associated variants within the human complement component 4 locus are associated with increased neuronal complement deposition and synapse uptake; however, they do not fully explain the observed increase in synapse uptake. Finally, we demonstrate that the antibiotic minocycline reduces microglia-mediated synapse uptake in vitro and its use is associated with a modest decrease in incident schizophrenia risk compared to other antibiotics in a cohort of young adults drawn from electronic health records. These findings point to excessive pruning as a potential target for delaying or preventing the onset of schizophrenia in high-risk individuals.
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Affiliation(s)
- Carl M Sellgren
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA. .,Department of Psychiatry, Harvard Medical School, Boston, MA, USA. .,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
| | - Jessica Gracias
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA.,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Bradley Watmuff
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Jonathan D Biag
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Jessica M Thanos
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | | | - Ting Fu
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | | | - Hannah E Brown
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Jennifer Wang
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Ajamete Kaykas
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Rakesh Karmacharya
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA.,Schizophrenia and Bipolar Disorder Program, McLean Hospital, Belmont, MA, USA
| | | | - Steven D Sheridan
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA.,Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Roy H Perlis
- Center for Quantitative Health, Center for Genomic Medicine and Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA. .,Department of Psychiatry, Harvard Medical School, Boston, MA, USA.
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17
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Eschenburg S, Reubold TF. Modulation of dynamin function by small molecules. Biol Chem 2018; 399:1421-1432. [PMID: 30067507 DOI: 10.1515/hsz-2018-0257] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 07/17/2018] [Indexed: 02/05/2023]
Abstract
Dynamins are essential as membrane remodelers in various cellular processes, like receptor-mediated endocytosis, synaptic vesicle recycling and spermatogenesis. Moreover, dynamin is involved in the internalization of numerous viruses and in the motility of several cancer cell lines. As tools for dissecting the underlying mechanisms of these important biological processes and as potential future therapeutics, small molecules have been developed in the last two decades that modulate the functions of dynamin. In this review we give an overview of the compound classes that are currently in use and describe how they affect dynamin function.
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Affiliation(s)
- Susanne Eschenburg
- Medizinische Hochschule Hannover, Institut für Biophysikalische Chemie, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
| | - Thomas F Reubold
- Medizinische Hochschule Hannover, Institut für Biophysikalische Chemie, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
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18
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Abstract
Synaptic pruning is dominant in early ontogenesis when a large number of unnecessary synapses are eliminated, and it maintains synaptic plasticity in the mature healthy brain, e.g., in memory processes. Its malfunction is involved in degenerative diseases such as Alzheimer’s disease. C1q, a member of the immune complement system, plays a central role in the selective pruning of synapses by microglial phagocytosis. Understanding the molecular aspects of complement-mediated synapse elimination is of high importance for developing effective therapeutic interventions in the future. Our analysis on C1q-tagged synaptosomes revealed that C1q label-based synaptic pruning is linked to local apoptotic-like processes in synapses. C1q, a member of the immune complement cascade, is implicated in the selective pruning of synapses by microglial phagocytosis. C1q-mediated synapse elimination has been shown to occur during brain development, while increased activation and complement-dependent synapse loss is observed in neurodegenerative diseases. However, the molecular mechanisms underlying C1q-controlled synaptic pruning are mostly unknown. This study addresses distortions in the synaptic proteome leading to C1q-tagged synapses. Our data demonstrated the preferential localization of C1q to the presynapse. Proteomic investigation and pathway analysis of C1q-tagged synaptosomes revealed the presence of apoptotic-like processes in C1q-tagged synapses, which was confirmed experimentally with apoptosis markers. Moreover, the induction of synaptic apoptotic-like mechanisms in a model of sensory deprivation-induced synaptic depression led to elevated C1q levels. Our results unveiled that C1q label-based synaptic pruning is triggered by and directly linked to apoptotic-like processes in the synaptic compartment.
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19
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Prieto GA, Tong L, Smith ED, Cotman CW. TNFα and IL-1β but not IL-18 Suppresses Hippocampal Long-Term Potentiation Directly at the Synapse. Neurochem Res 2018; 44:49-60. [PMID: 29619614 DOI: 10.1007/s11064-018-2517-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 03/20/2018] [Accepted: 03/22/2018] [Indexed: 12/13/2022]
Abstract
CNS inflammatory responses are linked to cognitive impairment in humans. Research in animal models supports this connection by showing that inflammatory cytokines suppress long-term potentiation (LTP), the best-known cellular correlate of memory. Cytokine-induced modulation of LTP has been previously studied in vivo or in brain slices, two experimental approaches containing multiple cell populations responsive to cytokines. In their target cells, cytokines commonly increase the expression of multiple cytokines, thus increasing the complexity of brain cytokine networks even after single-cytokine challenges. Whether cytokines suppress LTP by direct effects on neurons or by indirect mechanisms is still an open question. Here, we evaluated the effect of a major set of inflammatory cytokines including tumor necrosis factor-α (TNFα), interleukin-1β (IL-1β) and interleukin-18 (IL-18) on chemically-induced LTP (cLTP) in isolated hippocampal synaptosomes of mice, using fluorescence analysis of single-synapse long-term potentiation (FASS-LTP). We found that TNFα and IL-1β suppress synaptosomal cLTP. In contrast, cLTP was not affected by IL-18, at a concentration previously shown to block LTP in hippocampal slices. We also found that IL-18 does not impair cLTP or brain-derived neurotrophic factor (BDNF) signaling in primary hippocampal neuronal cultures. Thus, using both synaptosomes and neuron cultures, our data suggest that IL-18 impairs LTP by indirect mechanisms, which may depend on non-neuronal cells, such as glia. Notably, our results demonstrate that TNFα and IL-1β directly suppress hippocampal plasticity via neuron-specific mechanisms. A better understanding of the brain's cytokine networks and their final molecular effectors is crucial to identify specific targets for intervention.
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Affiliation(s)
- G Aleph Prieto
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA.
| | - Liqi Tong
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA
| | - Erica D Smith
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA
| | - Carl W Cotman
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA
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20
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21
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Rodriguez-Valle M, Moolhuijzen P, Barrero RA, Ong CT, Busch G, Karbanowicz T, Booth M, Clark R, Koehbach J, Ijaz H, Broady K, Agnew K, Knowles AG, Bellgard MI, Tabor AE. Transcriptome and toxin family analysis of the paralysis tick, Ixodes holocyclus. Int J Parasitol 2018; 48:71-82. [DOI: 10.1016/j.ijpara.2017.07.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/26/2017] [Accepted: 07/31/2017] [Indexed: 01/24/2023]
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22
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Florenzano F, Veronica C, Ciasca G, Ciotti MT, Pittaluga A, Olivero G, Feligioni M, Iannuzzi F, Latina V, Maria Sciacca MF, Sinopoli A, Milardi D, Pappalardo G, Marco DS, Papi M, Atlante A, Bobba A, Borreca A, Calissano P, Amadoro G. Extracellular truncated tau causes early presynaptic dysfunction associated with Alzheimer's disease and other tauopathies. Oncotarget 2017; 8:64745-64778. [PMID: 29029390 PMCID: PMC5630290 DOI: 10.18632/oncotarget.17371] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 04/11/2017] [Indexed: 12/14/2022] Open
Abstract
The largest part of tau secreted from AD nerve terminals and released in cerebral spinal fluid (CSF) is C-terminally truncated, soluble and unaggregated supporting potential extracellular role(s) of NH2 -derived fragments of protein on synaptic dysfunction underlying neurodegenerative tauopathies, including Alzheimer's disease (AD). Here we show that sub-toxic doses of extracellular-applied human NH2 tau 26-44 (aka NH 2 htau) -which is the minimal active moiety of neurotoxic 20-22kDa peptide accumulating in vivo at AD synapses and secreted into parenchyma- acutely provokes presynaptic deficit in K+ -evoked glutamate release on hippocampal synaptosomes along with alteration in local Ca2+ dynamics. Neuritic dystrophy, microtubules breakdown, deregulation in presynaptic proteins and loss of mitochondria located at nerve endings are detected in hippocampal cultures only after prolonged exposure to NH 2 htau. The specificity of these biological effects is supported by the lack of any significant change, either on neuronal activity or on cellular integrity, shown by administration of its reverse sequence counterpart which behaves as an inactive control, likely due to a poor conformational flexibility which makes it unable to dynamically perturb biomembrane-like environments. Our results demonstrate that one of the AD-relevant, soluble and secreted N-terminally truncated tau forms can early contribute to pathology outside of neurons causing alterations in synaptic activity at presynaptic level, independently of overt neurodegeneration.
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Affiliation(s)
| | | | - Gabriele Ciasca
- Institute of Physics, Catholic University of the Sacred Heart, Largo F Vito 1, Rome, Italy
| | - Maria Teresa Ciotti
- Institute of Cellular Biology and Neuroscience, CNR, IRCSS Santa Lucia Foundation, Rome, Italy
| | - Anna Pittaluga
- Department of Pharmacy, Pharmacology and Toxicology Section, University of Genoa, Genoa, Viale Cembrano, Italy
| | - Gunedalina Olivero
- Department of Pharmacy, Pharmacology and Toxicology Section, University of Genoa, Genoa, Viale Cembrano, Italy
| | - Marco Feligioni
- European Brain Research Institute, Rome, Italy
- Department of Neurorehabilitation Sciences, Casa Cura Policlinico, Milan, Italy
| | | | | | | | | | - Danilo Milardi
- Institute of Biostructures and Bioimaging, CNR, Catania, Italy
| | | | - De Spirito Marco
- Institute of Physics, Catholic University of the Sacred Heart, Largo F Vito 1, Rome, Italy
| | - Massimiliano Papi
- Institute of Physics, Catholic University of the Sacred Heart, Largo F Vito 1, Rome, Italy
| | - Anna Atlante
- Institute of Biomembranes and Bioenergetics, CNR, Bari, Italy
- Center of Excellence for Biomedical Research, University of Genoa, Genoa, Viale Benedetto XV, Italy
| | - Antonella Bobba
- Institute of Biomembranes and Bioenergetics, CNR, Bari, Italy
- Center of Excellence for Biomedical Research, University of Genoa, Genoa, Viale Benedetto XV, Italy
| | - Antonella Borreca
- Institute of Cellular Biology and Neuroscience, CNR, IRCSS Santa Lucia Foundation, Rome, Italy
| | | | - Giuseppina Amadoro
- European Brain Research Institute, Rome, Italy
- Institute of Translational Pharmacology, CNR, Rome, Italy
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23
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Girada SB, Kuna RS, Bele S, Zhu Z, Chakravarthi NR, DiMarchi RD, Mitra P. Gαs regulates Glucagon-Like Peptide 1 Receptor-mediated cyclic AMP generation at Rab5 endosomal compartment. Mol Metab 2017; 6:1173-1185. [PMID: 29031718 PMCID: PMC5641683 DOI: 10.1016/j.molmet.2017.08.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 07/30/2017] [Accepted: 08/04/2017] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVE Upon activation, G protein coupled receptors (GPCRs) associate with heterotrimeric G proteins at the plasma membrane to initiate second messenger signaling. Subsequently, the activated receptor experiences desensitization, internalization, and recycling back to the plasma membrane, or it undergoes lysosomal degradation. Recent reports highlight specific cases of persistent cyclic AMP generation by internalized GPCRs, although the functional significance and mechanistic details remain to be defined. Cyclic AMP generation from internalized Glucagon-Like Peptide-1 Receptor (GLP-1R) has previously been reported from our laboratory. This study aimed at deciphering the molecular mechanism by which internalized GLP-R supports sustained cyclic AMP generation upon receptor activation in pancreatic beta cells. METHODS We studied the time course of cyclic AMP generation following GLP-1R activation with particular emphasis on defining the location where cyclic AMP is generated. Detection involved a novel GLP-1 conjugate coupled with immunofluorescence using specific endosomal markers. Finally, we employed co-immunoprecipitation as well as immunofluorescence to assess the protein-protein interactions that regulate GLP-1R mediated cyclic AMP generation at endosomes. RESULTS Our data reveal that prolonged association of G protein α subunit Gαs with activated GLP-1R contributed to sustained cyclic AMP generation at Rab 5 endosomal compartment. CONCLUSIONS The findings provide the mechanism of endosomal cyclic AMP generation following GLP-1R activation. We identified the specific compartment that serves as an organizing center to generate endosomal cyclic AMP by internalized activated receptor complex.
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Affiliation(s)
- Shravan Babu Girada
- Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad, Telangana, 500046, India
| | - Ramya S Kuna
- Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad, Telangana, 500046, India
| | - Shilpak Bele
- Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad, Telangana, 500046, India
| | - Zhimeng Zhu
- Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - N R Chakravarthi
- Centre for Cellular and Molecular Biology, Habsiguda, Uppal Road, Hyderabad, 500007, India
| | | | - Prasenjit Mitra
- Dr. Reddy's Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad, Telangana, 500046, India.
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24
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The Study of Postmortem Human Synaptosomes for Understanding Alzheimer's Disease and Other Neurological Disorders: A Review. Neurol Ther 2017; 6:57-68. [PMID: 28733958 PMCID: PMC5520816 DOI: 10.1007/s40120-017-0070-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Indexed: 12/12/2022] Open
Abstract
Synaptic dysfunction is thought to play important roles in the pathophysiology of many neurological diseases, including Alzheimer’s disease, Parkinson’s disease, and schizophrenia. Over the past few decades, there have been systematic efforts to collect postmortem brain tissues via autopsies, leading to the establishment of dozens of human brain banks around the world. From cryopreserved human brain tissues, it is possible to isolate detached-and-resealed synaptic terminals termed synaptosomes, which remain metabolically and enzymatically active. Synaptosomes have become important model systems for studying human synaptic functions, being much more accessible than ex vivo brain slices or primary neuronal cultures. Here we review recent advances in the establishment of human brain banks, the isolation of synaptosomes, their biological activities, and various analytical techniques for investigating their biochemical and ultrastructural properties. There are unique insights to be gained by directly examining human synaptosomes, which cannot be substituted by animal models. We will also discuss how human synaptosome research has contributed to better understanding of neurological disorders, especially Alzheimer’s disease.
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25
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Prieto GA, Cotman CW. Cytokines and cytokine networks target neurons to modulate long-term potentiation. Cytokine Growth Factor Rev 2017; 34:27-33. [PMID: 28377062 PMCID: PMC5491344 DOI: 10.1016/j.cytogfr.2017.03.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 03/28/2017] [Indexed: 12/20/2022]
Abstract
Cytokines play crucial roles in the communication between brain cells including neurons and glia, as well as in the brain-periphery interactions. In the brain, cytokines modulate long-term potentiation (LTP), a cellular correlate of memory. Whether cytokines regulate LTP by direct effects on neurons or by indirect mechanisms mediated by non-neuronal cells is poorly understood. Elucidating neuron-specific effects of cytokines has been challenging because most brain cells express cytokine receptors. Moreover, cytokines commonly increase the expression of multiple cytokines in their target cells, thus increasing the complexity of brain cytokine networks even after single-cytokine challenges. Here, we review evidence on both direct and indirect-mediated modulation of LTP by cytokines. We also describe novel approaches based on neuron- and synaptosome-enriched systems to identify cytokines able to directly modulate LTP, by targeting neurons and synapses. These approaches can test multiple samples in parallel, thus allowing the study of multiple cytokines simultaneously. Hence, a cytokine networks perspective coupled with neuron-specific analysis may contribute to delineation of maps of the modulation of LTP by cytokines.
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Affiliation(s)
- G Aleph Prieto
- Institute for Memory Impairments and Neurological Disorders, University of California-Irvine, Irvine, CA 92697, USA.
| | - Carl W Cotman
- Institute for Memory Impairments and Neurological Disorders, University of California-Irvine, Irvine, CA 92697, USA
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26
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Ly S, Navaroli DM, Didiot MC, Cardia J, Pandarinathan L, Alterman JF, Fogarty K, Standley C, Lifshitz LM, Bellve KD, Prot M, Echeverria D, Corvera S, Khvorova A. Visualization of self-delivering hydrophobically modified siRNA cellular internalization. Nucleic Acids Res 2017; 45:15-25. [PMID: 27899655 PMCID: PMC5224471 DOI: 10.1093/nar/gkw1005] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 10/07/2016] [Accepted: 10/24/2016] [Indexed: 01/07/2023] Open
Abstract
siRNAs are a new class of therapeutic modalities with promising clinical efficacy that requires modification or formulation for delivery to the tissue and cell of interest. Conjugation of siRNAs to lipophilic groups supports efficient cellular uptake by a mechanism that is not well characterized. Here we study the mechanism of internalization of asymmetric, chemically stabilized, cholesterol-modified siRNAs (sd-rxRNAs®) that efficiently enter cells and tissues without the need for formulation. We demonstrate that uptake is rapid with significant membrane association within minutes of exposure followed by the formation of vesicular structures and internalization. Furthermore, sd-rxRNAs are internalized by a specific class of early endosomes and show preferential association with epidermal growth factor (EGF) but not transferrin (Tf) trafficking pathways as shown by live cell TIRF and structured illumination microscopy (SIM). In fixed cells, we observe ∼25% of sd-rxRNA co-localizing with EGF and <5% with Tf, which is indicative of selective endosomal sorting. Likewise, preferential sd-rxRNA co-localization was demonstrated with EEA1 but not RBSN-containing endosomes, consistent with preferential EGF-like trafficking through EEA1-containing endosomes. sd-rxRNA cellular uptake is a two-step process, with rapid membrane association followed by internalization through a selective, saturable subset of the endocytic process. However, the mechanistic role of EEA1 is not yet known. This method of visualization can be used to better understand the kinetics and mechanisms of hydrophobic siRNA cellular uptake and will assist in further optimization of these types of compounds for therapeutic intervention.
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Affiliation(s)
- Socheata Ly
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Deanna M Navaroli
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Marie-Cécile Didiot
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | | | | | - Julia F Alterman
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Kevin Fogarty
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Clive Standley
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Lawrence M Lifshitz
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Karl D Bellve
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Matthieu Prot
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Dimas Echeverria
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Silvia Corvera
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Anastasia Khvorova
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655, USA
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01655, USA
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Pharmacological Rescue of Long-Term Potentiation in Alzheimer Diseased Synapses. J Neurosci 2016; 37:1197-1212. [PMID: 27986924 DOI: 10.1523/jneurosci.2774-16.2016] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 12/05/2016] [Accepted: 12/09/2016] [Indexed: 01/05/2023] Open
Abstract
Long-term potentiation (LTP) is an activity-dependent and persistent increase in synaptic transmission. Currently available techniques to measure LTP are time-intensive and require highly specialized expertise and equipment, and thus are not well suited for screening of multiple candidate treatments, even in animal models. To expand and facilitate the analysis of LTP, here we use a flow cytometry-based method to track chemically induced LTP by detecting surface AMPA receptors in isolated synaptosomes: fluorescence analysis of single-synapse long-term potentiation (FASS-LTP). First, we demonstrate that FASS-LTP is simple, sensitive, and models electrically induced LTP recorded in intact circuitries. Second, we conducted FASS-LTP analysis in two well-characterized Alzheimer's disease (AD) mouse models (3xTg and Tg2576) and, importantly, in cryopreserved human AD brain samples. By profiling hundreds of synaptosomes, our data provide the first direct evidence to support the idea that synapses from AD brain are intrinsically defective in LTP. Third, we used FASS-LTP for drug evaluation in human synaptosomes. Testing a panel of modulators of cAMP and cGMP signaling pathways, FASS-LTP identified vardenafil and Bay-73-6691 (phosphodiesterase-5 and -9 inhibitors, respectively) as potent enhancers of LTP in synaptosomes from AD cases. These results indicate that our approach could provide the basis for protocols to study LTP in both healthy and diseased human brains, a previously unattainable goal. SIGNIFICANCE STATEMENT Learning and memory depend on the ability of synapses to strengthen in response to activity. Long-term potentiation (LTP) is a rapid and persistent increase in synaptic transmission that is thought to be affected in Alzheimer's disease (AD). However, direct evidence of LTP deficits in human AD brain has been elusive, primarily due to methodological limitations. Here, we analyze LTP in isolated synapses from AD brain using a novel approach that allows testing LTP in cryopreserved brain. Our analysis of hundreds of synapses supports the idea that AD-diseased synapses are intrinsically defective in LTP. Further, we identified pharmacological agents that rescue LTP in AD, thus opening up a new avenue for drug screening and evaluation of strategies for alleviating memory impairments.
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Regulation of ATP13A2 via PHD2-HIF1α Signaling Is Critical for Cellular Iron Homeostasis: Implications for Parkinson's Disease. J Neurosci 2016; 36:1086-95. [PMID: 26818499 DOI: 10.1523/jneurosci.3117-15.2016] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
UNLABELLED We previously reported that pharmacological inhibition of a class of enzymes known as prolyl hydroxylase domain proteins (PHDs) has neuroprotective effects in various in vitro and in vivo models of Parkinson's disease (PD). We hypothesized that this was due to inhibition of the PHD2 isoform, preventing it from hydroxylating the transcription factor hypoxia inducible factor 1 α (HIF1α), targeting it for eventual proteasomal degradation. HIF1α itself induces the transcription of various cellular stress genes, including several involved in iron metabolism. Although all three isoforms of PHD are expressed within vulnerable dopaminergic (DAergic) substantia nigra pars compacta neurons, only select downregulation of the PHD2 isoform was found to protect against in vivo neurodegenerative effects associated with the mitochondrial neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. These findings were corroborated in induced pluripotent stem cell-derived neurons, providing validation in a pertinent human cell model. PHD2 inhibition was found to result in increased expression of ATP13A2, mutation of which is responsible for a rare juvenile form of PD known as Kufor-Rakeb syndrome. Knockdown of ATP13A2 expression within human DAergic cells was found to abrogate restoration of cellular iron homeostasis and neuronal cell viability elicited by inhibition of PHD2 under conditions of mitochondrial stress, likely via effects on lysosomal iron storage. These data suggest that regulation of ATP13A2 by the PHD2-HIF1α signaling pathway affects cellular iron homeostasis and DAergic neuronal survival. This constitutes a heretofore unrecognized process associated with loss of ATP13A2 function that could have wide-ranging implications for it as a therapeutic target for PD and other related conditions. SIGNIFICANCE STATEMENT Reductions in PHD2 activity within dopaminergic neurons in vivo and in cultured human induced pluripotent stem cell-derived neurons protects against mitochondrial stress-induced neurotoxicity. Protective effects are dependent on downstream HIF-1α expression. Knockdown of ATP13A2, a gene linked to a rare juvenile form of Parkinson's disease and recently identified as a novel HIF1α target, was found to abrogate maintenance of cellular iron homeostasis and neuronal viability elicited by PHD2 inhibition in vivo and in cultured dopaminergic cells under conditions of mitochondrial stress. Mechanistically, this was due to ATP13A2's role in maintaining lysosomal iron stores. This constitutes a novel mechanism by which alterations in ATP13A2 activity may be driving PD-related neuropathology.
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Kohansal-Nodehi M, Chua JJ, Urlaub H, Jahn R, Czernik D. Analysis of protein phosphorylation in nerve terminal reveals extensive changes in active zone proteins upon exocytosis. eLife 2016; 5. [PMID: 27115346 PMCID: PMC4894758 DOI: 10.7554/elife.14530] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/25/2016] [Indexed: 12/31/2022] Open
Abstract
Neurotransmitter release is mediated by the fast, calcium-triggered fusion of synaptic vesicles with the presynaptic plasma membrane, followed by endocytosis and recycling of the membrane of synaptic vesicles. While many of the proteins governing these processes are known, their regulation is only beginning to be understood. Here we have applied quantitative phosphoproteomics to identify changes in phosphorylation status of presynaptic proteins in resting and stimulated nerve terminals isolated from the brains of Wistar rats. Using rigorous quantification, we identified 252 phosphosites that are either up- or downregulated upon triggering calcium-dependent exocytosis. Particularly pronounced were regulated changes of phosphosites within protein constituents of the presynaptic active zone, including bassoon, piccolo, and RIM1. Additionally, we have mapped kinases and phosphatases that are activated upon stimulation. Overall, our study provides a snapshot of phosphorylation changes associated with presynaptic activity and provides a foundation for further functional analysis of key phosphosites involved in presynaptic plasticity. DOI:http://dx.doi.org/10.7554/eLife.14530.001 The human nervous system contains more than a hundred billion neurons that are connected with each other via junctions called synapses. When an electrical impulse travelling along a neuron arrives at a synapse, it triggers bubble-like packages called synaptic vesicles within the neuron to merge with the neuron’s surface membrane. The contents of these vesicles – chemical messengers called neurotransmitters – are then released into the synapse and carry the signal to the next neuron. Complex molecular machines made from many different proteins control the release of neurotransmitters. Quite a few of these proteins are regulated by the addition of phosphate groups at specific sites. However, not all of the proteins involved in the release of neurotransmitters have been studied in detail and it is largely unclear how most of them are regulated. Now, Kohansal-Nodehi et al. have used techniques involving mass spectrometry to find out which proteins have phosphate groups added or removed in neurons that are releasing neurotransmitters. The experiments used pinched-off synapses isolated from rat brains. These structures, referred to as “synaptosomes”, lend themselves to this kind of study because they can be induced to continuously release neurotransmitters for several minutes. Kohansal-Nodehi et al. identified over 250 specific sites on proteins in the synaptosomes where phosphate groups are attached, including many on the key proteins known to operate in neurotransmitter release. Moreover, some proteins were modified at multiple sites, especially the proteins that form a scaffold to capture synaptic vesicles close to the membrane and prepare them for release. The data also revealed important clues about the enzymes that either attach or remove the phosphate groups. Together, these findings provide new insights into the regulatory networks that control many proteins at the same time. The next challenge is to sort out which of these modifications change the interactions between the proteins that control neurotransmitter release, and to understand how these changes influence the trafficking of synaptic vesicles. DOI:http://dx.doi.org/10.7554/eLife.14530.002
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Affiliation(s)
| | - John Je Chua
- Interactomics and Intracellular Trafficking laboratory, National University of Singapore, Singapore, Singapore.,Department of Physiology, National University of Singapore, Singapore, Singapore.,Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Neurobiology/Ageing Programme, National University of Singapore, Singapore, Singapore
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Bioanalytics Group, University Medical Center Göttingen, Göttingen, Germany
| | - Reinhard Jahn
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Dominika Czernik
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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Franklin W, Taglialatela G. A method to determine insulin responsiveness in synaptosomes isolated from frozen brain tissue. J Neurosci Methods 2016; 261:128-34. [PMID: 26774027 DOI: 10.1016/j.jneumeth.2016.01.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 12/11/2015] [Accepted: 01/02/2016] [Indexed: 01/16/2023]
Abstract
BACKGROUND Studying the insulin signaling response at the synapse is an important approach to understand molecular mechanisms involved in disease-related neurodegenerative processes. NEW METHOD We developed a method for studying the insulin responsiveness at the synaptic level by isolating functional synaptosomes from fresh or frozen tissue and exposing them to insulin in the presence of ATP (a critical step) to detect insulin receptor (IR) activation. RESULTS We performed an ATP dose-response curve, insulin dose-response curve, and insulin response time course to optimize this method. We also demonstrated that our protocol reflects the degree of insulin responsiveness in vivo by using an animal model of known insulin resistance, AtENPP1-Tg mice. COMPARISON WITH EXISTING METHOD(S) This method is advantageous over other methods detecting IR in total brain homogenates due to the ability to detect IR response without confounding contributions from other cell areas and cell types also expressing IR. Furthermore, ex vivo insulin stimulation can be compared to baseline synaptosomes obtained from the same animal which improves reliability and statistical power while decreasing the number of animals required to perform individual experiments. CONCLUSIONS We have developed a reliable, efficient method to measure insulin-driven ex vivo phosphorylation of the synaptosomal insulin receptor that can reliably reflect the pre-existing insulin responsiveness status in the CNS of the animal. To the best of our knowledge, this is the first evidence of stimulation of isolated synaptosomes with insulin and a promising new technique to study the synaptic CNS insulin responsiveness under physiological or disease conditions.
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Affiliation(s)
- Whitney Franklin
- Mitchell Center for Neurodegenerative Diseases, Department of Neurology, University of Texas Medical Branch, Galveston, TX, USA; Department of Neuroscience & Cell Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Giulio Taglialatela
- Mitchell Center for Neurodegenerative Diseases, Department of Neurology, University of Texas Medical Branch, Galveston, TX, USA.
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31
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Depner H, Lützkendorf J, Babkir HA, Sigrist SJ, Holt MG. Differential centrifugation-based biochemical fractionation of the Drosophila adult CNS. Nat Protoc 2014; 9:2796-808. [PMID: 25393777 DOI: 10.1038/nprot.2014.192] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Drosophila is widely used as a genetic model in questions of development, cellular function and disease. Genetic screens in flies have proven to be incredibly powerful in identifying crucial components for synapse formation and function, particularly in the case of the presynaptic release machinery. Although modern biochemical methods can identify individual proteins and lipids (and their binding partners), they have typically been excluded from use in Drosophila for technical reasons. To bridge this essential gap between genetics and biochemistry, we developed a fractionation method to isolate various parts of the synaptic machinery from Drosophila, thus allowing it to be studied in unprecedented biochemical detail. This is only possible because our protocol has unique advantages in terms of enriching and preserving endogenous protein complexes. The procedure involves decapitation of adult flies, homogenization and differential centrifugation of fly heads, which allow subsequent purification of presynaptic (and to a limited degree postsynaptic) components. It is designed to require only a rudimentary knowledge of biochemical fractionation, and it takes ∼3.5 h. The yield is typically 4 mg of synaptic membrane protein per gram of Drosophila heads.
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Affiliation(s)
- Harald Depner
- Institute for Biology - Genetics, Freie Universität Berlin, Berlin, Germany
| | - Janine Lützkendorf
- Institute for Biology - Genetics, Freie Universität Berlin, Berlin, Germany
| | - Husam A Babkir
- Institute for Biology - Genetics, Freie Universität Berlin, Berlin, Germany
| | - Stephan J Sigrist
- 1] Institute for Biology - Genetics, Freie Universität Berlin, Berlin, Germany. [2] NeuroCure Cluster of Excellence, Charité, Berlin, Germany
| | - Matthew G Holt
- Laboratory of Glia Biology, Vlaams Instituut voor Biotechnologie (VIB) Center for the Biology of Disease, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
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32
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Chang RYK, Etheridge N, Dodd PR, Nouwens AS. Targeted quantitative analysis of synaptic proteins in Alzheimer’s disease brain. Neurochem Int 2014; 75:66-75. [DOI: 10.1016/j.neuint.2014.05.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 05/22/2014] [Accepted: 05/26/2014] [Indexed: 11/15/2022]
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Abstract
Dynamin is a large GTPase with roles in membrane fission during clathrin-mediated endocytosis, in actin dynamics and in cytokinesis. Defects in dynamin have been linked to human diseases. The synthesis of a dynamin modulator toolkit comprising two different inhibitor classes is described. The first series comprises Dynole 34-2, Dynole 2-24 and the inactive control Dynole 31-2. The Dynole compounds act on the dynamin G domain, are not GTP competitive and can be synthesized in 2-3 d. Knoevenagel condensation of 1-(3-(dimethylamino)propyl)-1H-indole-3-carbaldehyde (1) with cyanoamides (2 and 3) affords Dynole 31-2 and Dynole 34-2, respectively. Reductive amination of 1 with decylamine gives Dynole 2-24. The second series acts at an allosteric site in the G domain of dynamin and comprises Dyngo 4a and Dyngo Ø (inactive control). Both are synthesized in an overnight reaction via condensation of 3-hydroxy-2-naphthoic hydrazide with 2,4,5-trihydroxybenzaldehyde to afford Dyngo 4a, or with benzaldehyde to afford Dyngo Ø.
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Abstract
Synaptic vesicle recycling sustains high rates of neurotransmission at the ribbon-type active zones (AZs) of mouse auditory inner hair cells (IHCs), but its modes and molecular regulation are poorly understood. Electron microscopy indicated the presence of clathrin-mediated endocytosis (CME) and bulk endocytosis. The endocytic proteins dynamin, clathrin, and amphiphysin are expressed and broadly distributed in IHCs. We used confocal vglut1-pHluorin imaging and membrane capacitance (Cm) measurements to study the spatial organization and dynamics of IHC exocytosis and endocytosis. Viral gene transfer expressed vglut1-pHluorin in IHCs and targeted it to synaptic vesicles. The intravesicular pH was ∼6.5, supporting only a modest increase of vglut1-pHluorin fluorescence during exocytosis and pH neutralization. Ca(2+) influx triggered an exocytic increase of vglut1-pHluorin fluorescence at the AZs, around which it remained for several seconds. The endocytic Cm decline proceeded with constant rate (linear component) after exocytosis of the readily releasable pool (RRP). When exocytosis exceeded three to four RRP equivalents, IHCs additionally recruited a faster Cm decline (exponential component) that increased with the amount of preceding exocytosis and likely reflects bulk endocytosis. The dynamin inhibitor Dyngo-4a and the clathrin blocker pitstop 2 selectively impaired the linear component of endocytic Cm decline. A missense mutation of dynamin 1 (fitful) inhibited endocytosis to a similar extent as Dyngo-4a. We propose that IHCs use dynamin-dependent endocytosis via CME to support vesicle cycling during mild stimulation but recruit bulk endocytosis to balance massive exocytosis.
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35
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Nath AR, Chen RHC, Stanley EF. Cryoloading: introducing large molecules into live synaptosomes. Front Cell Neurosci 2014; 8:4. [PMID: 24478628 PMCID: PMC3899522 DOI: 10.3389/fncel.2014.00004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 01/06/2014] [Indexed: 11/13/2022] Open
Abstract
Neurons communicate with their target cells primarily by the release of chemical transmitters from presynaptic nerve terminals. The study of CNS presynaptic nerve terminals, isolated as synaptosomes (SSMs) has, however, been hampered by the typical small size of these structures that precludes the introduction of non-membrane permeable test substances such as peptides and drugs. We have developed a method to introduce large alien compounds of at least 150 kDa into functional synaptosomes. Purified synaptosomes are frozen in cryo-preserving buffer containing the alien compound. Upon defrosting, many of the SSMs contain the alien compound presumably admitted by bulk buffer-transfer through the surface membranes that crack and reseal during the freeze/thaw cycle. ~80% of the cryoloaded synaptosomes were functional and recycled synaptic vesicles (SVs), as assessed by a standard styryl dye uptake assay. Access of the cryoloaded compound into the cytoplasm and biological activity were confirmed by block of depolarization-induced SV recycling with membrane-impermeant BAPTA (a rapid Ca(2+)-scavenger), or botulinum A light chain (which cleaves the soluble NSF attachment protein receptor (SNARE) protein SNAP25). A major advantage of the method is that loaded frozen synaptosomes can be stored virtually indefinitely for later experimentation. We also demonstrate that individual synaptosome types can be identified by immunostaining of receptors associated with its scab of attached postsynaptic membrane. Thus, cryoloading and scab-staining permits the examination of SV recycling in identified individual CNS presynaptic nerve terminals.
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Affiliation(s)
- Arup R Nath
- Laboratory of Synaptic Transmission, Toronto Western Research Institute Toronto, ON, Canada
| | - Robert H C Chen
- Laboratory of Synaptic Transmission, Toronto Western Research Institute Toronto, ON, Canada
| | - Elise F Stanley
- Laboratory of Synaptic Transmission, Toronto Western Research Institute Toronto, ON, Canada
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36
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McCluskey A, Daniel JA, Hadzic G, Chau N, Clayton EL, Mariana A, Whiting A, Gorgani NN, Lloyd J, Quan A, Moshkanbaryans L, Krishnan S, Perera S, Chircop M, von Kleist L, McGeachie AB, Howes MT, Parton RG, Campbell M, Sakoff JA, Wang X, Sun JY, Robertson MJ, Deane FM, Nguyen TH, Meunier FA, Cousin MA, Robinson PJ. Building a better dynasore: the dyngo compounds potently inhibit dynamin and endocytosis. Traffic 2013; 14:1272-89. [PMID: 24025110 PMCID: PMC4138991 DOI: 10.1111/tra.12119] [Citation(s) in RCA: 194] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 09/09/2013] [Accepted: 09/11/2013] [Indexed: 12/16/2022]
Abstract
Dynamin GTPase activity increases when it oligomerizes either into helices in the presence of lipid templates or into rings in the presence of SH3 domain proteins. Dynasore is a dynamin inhibitor of moderate potency (IC₅₀ ~ 15 μM in vitro). We show that dynasore binds stoichiometrically to detergents used for in vitro drug screening, drastically reducing its potency (IC₅₀ = 479 μM) and research tool utility. We synthesized a focused set of dihydroxyl and trihydroxyl dynasore analogs called the Dyngo™ compounds, five of which had improved potency, reduced detergent binding and reduced cytotoxicity, conferred by changes in the position and/or number of hydroxyl substituents. The Dyngo compound 4a was the most potent compound, exhibiting a 37-fold improvement in potency over dynasore for liposome-stimulated helical dynamin activity. In contrast, while dynasore about equally inhibited dynamin assembled in its helical or ring states, 4a and 6a exhibited >36-fold reduced activity against rings, suggesting that they can discriminate between helical or ring oligomerization states. 4a and 6a inhibited dynamin-dependent endocytosis of transferrin in multiple cell types (IC₅₀ of 5.7 and 5.8 μM, respectively), at least sixfold more potently than dynasore, but had no effect on dynamin-independent endocytosis of cholera toxin. 4a also reduced synaptic vesicle endocytosis and activity-dependent bulk endocytosis in cultured neurons and synaptosomes. Overall, 4a and 6a are improved and versatile helical dynamin and endocytosis inhibitors in terms of potency, non-specific binding and cytotoxicity. The data further suggest that the ring oligomerization state of dynamin is not required for clathrin-mediated endocytosis.
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Affiliation(s)
- Adam McCluskey
- Chemistry, Centre for Chemical Biology, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, 2308, Australia
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37
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McGeachie AB, Odell LR, Quan A, Daniel JA, Chau N, Hill TA, Gorgani NN, Keating DJ, Cousin MA, van Dam EM, Mariana A, Whiting A, Perera S, Novelle A, Young KA, Deane FM, Gilbert J, Sakoff JA, Chircop M, McCluskey A, Robinson PJ. Pyrimidyn compounds: dual-action small molecule pyrimidine-based dynamin inhibitors. ACS Chem Biol 2013; 8:1507-18. [PMID: 23642287 DOI: 10.1021/cb400137p] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Dynamin is required for clathrin-mediated endocytosis (CME). Its GTPase activity is stimulated by phospholipid binding to its PH domain, which induces helical oligomerization. We have designed a series of novel pyrimidine-based "Pyrimidyn" compounds that inhibit the lipid-stimulated GTPase activity of full length dynamin I and II with similar potency. The most potent analogue, Pyrimidyn 7, has an IC50 of 1.1 μM for dynamin I and 1.8 μM for dynamin II, making it among the most potent dynamin inhibitors identified to date. We investigated the mechanism of action of the Pyrimidyn compounds in detail by examining the kinetics of Pyrimidyn 7 inhibition of dynamin. The compound competitively inhibits both GTP and phospholipid interactions with dynamin I. While both mechanisms of action have been previously observed separately, this is the first inhibitor series to incorporate both and thereby to target two distinct domains of dynamin. Pyrimidyn 6 and 7 reversibly inhibit CME of both transferrin and EGF in a number of non-neuronal cell lines as well as inhibiting synaptic vesicle endocytosis (SVE) in nerve terminals. Therefore, Pyrimidyn compounds block endocytosis by directly competing with GTP and lipid binding to dynamin, limiting both the recruitment of dynamin to membranes and its activation. This dual mode of action provides an important new tool for molecular dissection of dynamin's role in endocytosis.
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Affiliation(s)
- Andrew B. McGeachie
- Cell Signalling Unit, Children’s
Medical Research Institute, The University of Sydney, Sydney, NSW 2145, Australia
| | - Luke R. Odell
- Centre for Chemical Biology,
Chemistry, The University of Newcastle,
Callaghan, NSW 2308, Australia
| | - Annie Quan
- Cell Signalling Unit, Children’s
Medical Research Institute, The University of Sydney, Sydney, NSW 2145, Australia
| | - James A. Daniel
- Cell Signalling Unit, Children’s
Medical Research Institute, The University of Sydney, Sydney, NSW 2145, Australia
| | - Ngoc Chau
- Cell Signalling Unit, Children’s
Medical Research Institute, The University of Sydney, Sydney, NSW 2145, Australia
| | - Timothy A. Hill
- Centre for Chemical Biology,
Chemistry, The University of Newcastle,
Callaghan, NSW 2308, Australia
| | - Nick N. Gorgani
- Cell Signalling Unit, Children’s
Medical Research Institute, The University of Sydney, Sydney, NSW 2145, Australia
| | - Damien J. Keating
- Department of Human Physiology, Flinders University, Adelaide, South Australia, 5001,
Australia
| | - Michael A. Cousin
- Department of Human Physiology, Flinders University, Adelaide, South Australia, 5001,
Australia
| | - Ellen M. van Dam
- The Garvan Institute, 384 Victoria Street,
Darlinghurst, Sydney, NSW 2010, Australia
| | - Anna Mariana
- Centre for Chemical Biology,
Chemistry, The University of Newcastle,
Callaghan, NSW 2308, Australia
| | | | - Swetha Perera
- Cell Signalling Unit, Children’s
Medical Research Institute, The University of Sydney, Sydney, NSW 2145, Australia
| | - Aimee Novelle
- Cell Signalling Unit, Children’s
Medical Research Institute, The University of Sydney, Sydney, NSW 2145, Australia
| | - Kelly A. Young
- Centre for Chemical Biology,
Chemistry, The University of Newcastle,
Callaghan, NSW 2308, Australia
| | - Fiona M. Deane
- Centre for Chemical Biology,
Chemistry, The University of Newcastle,
Callaghan, NSW 2308, Australia
| | - Jayne Gilbert
- Department
of Medical Oncology, Calvary Mater Newcastle Hospital, Waratah, NSW 2298,
Australia
| | - Jennette A. Sakoff
- Department
of Medical Oncology, Calvary Mater Newcastle Hospital, Waratah, NSW 2298,
Australia
| | - Megan Chircop
- Cell Signalling Unit, Children’s
Medical Research Institute, The University of Sydney, Sydney, NSW 2145, Australia
| | - Adam McCluskey
- Centre for Chemical Biology,
Chemistry, The University of Newcastle,
Callaghan, NSW 2308, Australia
| | - Phillip J. Robinson
- Cell Signalling Unit, Children’s
Medical Research Institute, The University of Sydney, Sydney, NSW 2145, Australia
| |
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Harper CB, Popoff MR, McCluskey A, Robinson PJ, Meunier FA. Targeting membrane trafficking in infection prophylaxis: dynamin inhibitors. Trends Cell Biol 2013; 23:90-101. [DOI: 10.1016/j.tcb.2012.10.007] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 10/11/2012] [Accepted: 10/11/2012] [Indexed: 12/01/2022]
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