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Blanco-Redondo B, Nuwal N, Kneitz S, Nuwal T, Halder P, Liu Y, Ehmann N, Scholz N, Mayer A, Kleber J, Kähne T, Schmitt D, Sadanandappa MK, Funk N, Albertova V, Helfrich-Förster C, Ramaswami M, Hasan G, Kittel RJ, Langenhan T, Gerber B, Buchner E. Implications of the Sap47 null mutation for synapsin phosphorylation, longevity, climbing proficiency and behavioural plasticity in adult Drosophila. ACTA ACUST UNITED AC 2019; 222:jeb.203505. [PMID: 31488622 DOI: 10.1242/jeb.203505] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 08/29/2019] [Indexed: 12/18/2022]
Abstract
The Sap47 gene of Drosophila melanogaster encodes a highly abundant 47 kDa synaptic vesicle-associated protein. Sap47 null mutants show defects in synaptic plasticity and larval olfactory associative learning but the molecular function of Sap47 at the synapse is unknown. We demonstrate that Sap47 modulates the phosphorylation of another highly abundant conserved presynaptic protein, synapsin. Site-specific phosphorylation of Drosophila synapsin has repeatedly been shown to be important for behavioural plasticity but it was not known where these phospho-synapsin isoforms are localized in the brain. Here, we report the distribution of serine-6-phosphorylated synapsin in the adult brain and show that it is highly enriched in rings of synapses in the ellipsoid body and in large synapses near the lateral triangle. The effects of knockout of Sap47 or synapsin on olfactory associative learning/memory support the hypothesis that both proteins operate in the same molecular pathway. We therefore asked if this might also be true for other aspects of their function. We show that knockout of Sap47 but not synapsin reduces lifespan, whereas knockout of Sap47 and synapsin, either individually or together, affects climbing proficiency, as well as plasticity in circadian rhythms and sleep. Furthermore, electrophysiological assessment of synaptic properties at the larval neuromuscular junction (NMJ) reveals increased spontaneous synaptic vesicle fusion and reduced paired pulse facilitation in Sap47 and synapsin single and double mutants. Our results imply that Sap47 and synapsin cooperate non-uniformly in the control of synaptic properties in different behaviourally relevant neuronal networks of the fruitfly.
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Affiliation(s)
- Beatriz Blanco-Redondo
- Institute of Clinical Neurobiology, University of Würzburg, 97078 Würzburg, Germany .,Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany.,Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Leipzig University, 04103 Leipzig, Germany
| | - Nidhi Nuwal
- Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Susanne Kneitz
- Department of Physiological Chemistry, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Tulip Nuwal
- Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Partho Halder
- Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Yiting Liu
- Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Nadine Ehmann
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany.,Department of Animal Physiology, Institute of Biology, Leipzig University, 04103 Leipzig, Germany.,Carl-Ludwig-Institute for Physiology, Leipzig University, 04103 Leipzig, Germany
| | - Nicole Scholz
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Leipzig University, 04103 Leipzig, Germany.,Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany
| | - Annika Mayer
- Institute of Clinical Neurobiology, University of Würzburg, 97078 Würzburg, Germany
| | - Jörg Kleber
- Leibniz Institute of Neurobiology, 39118 Magdeburg, Germany
| | - Thilo Kähne
- Institute of Experimental Internal Medicine, Otto von Guericke University, 39120 Magdeburg, Germany
| | - Dominique Schmitt
- Institute of Clinical Neurobiology, University of Würzburg, 97078 Würzburg, Germany
| | - Madhumala K Sadanandappa
- Institute of Clinical Neurobiology, University of Würzburg, 97078 Würzburg, Germany.,National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka 560065, India
| | - Natalja Funk
- Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Viera Albertova
- Institute of Clinical Neurobiology, University of Würzburg, 97078 Würzburg, Germany.,Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Charlotte Helfrich-Förster
- Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Mani Ramaswami
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka 560065, India
| | - Gaiti Hasan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka 560065, India
| | - Robert J Kittel
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany.,Department of Animal Physiology, Institute of Biology, Leipzig University, 04103 Leipzig, Germany.,Carl-Ludwig-Institute for Physiology, Leipzig University, 04103 Leipzig, Germany
| | - Tobias Langenhan
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Leipzig University, 04103 Leipzig, Germany.,Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany
| | - Bertram Gerber
- Leibniz Institute of Neurobiology, 39118 Magdeburg, Germany.,Institute of Biology, University of Magdeburg, 39120 Magdeburg, Germany.,Center for Behavioral Brain Sciences, 39106 Magdeburg, Germany
| | - Erich Buchner
- Institute of Clinical Neurobiology, University of Würzburg, 97078 Würzburg, Germany .,Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
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Funk N, Munz M, Ott T, Brockmann K, Wenninger-Weinzierl A, Kühn R, Vogt-Weisenhorn D, Giesert F, Wurst W, Gasser T, Biskup S. The Parkinson's disease-linked Leucine-rich repeat kinase 2 (LRRK2) is required for insulin-stimulated translocation of GLUT4. Sci Rep 2019; 9:4515. [PMID: 30872638 PMCID: PMC6418296 DOI: 10.1038/s41598-019-40808-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 02/19/2019] [Indexed: 02/07/2023] Open
Abstract
Mutations within Leucine-rich repeat kinase 2 (LRRK2) are associated with late-onset Parkinson's disease. The physiological function of LRRK2 and molecular mechanism underlying the pathogenic role of LRRK2 mutations remain uncertain. Here, we investigated the role of LRRK2 in intracellular signal transduction. We find that deficiency of Lrrk2 in rodents affects insulin-dependent translocation of glucose transporter type 4 (GLUT4). This deficit is restored during aging by prolonged insulin-dependent activation of protein kinase B (PKB, Akt) and Akt substrate of 160 kDa (AS160), and is compensated by elevated basal expression of GLUT4 on the cell surface. Furthermore, we find a crucial role of Rab10 phosphorylation by LRRK2 for efficient insulin signal transduction. Translating our findings into human cell lines, we find comparable molecular alterations in fibroblasts from Parkinson's patients with the known pathogenic G2019S LRRK2 mutation. Our results highlight the role of LRRK2 in insulin-dependent signalling with potential therapeutic implications.
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Affiliation(s)
- Natalja Funk
- Hertie Institute for Clinical Brain Research and German Center for Neurodegenerative Diseases, University Clinic Tuebingen, Tuebingen, Germany.
| | - Marita Munz
- Hertie Institute for Clinical Brain Research and German Center for Neurodegenerative Diseases, University Clinic Tuebingen, Tuebingen, Germany
| | - Thomas Ott
- IZKF Facility for Transgenic Animals, Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany
| | - Kathrin Brockmann
- Hertie Institute for Clinical Brain Research and German Center for Neurodegenerative Diseases, University Clinic Tuebingen, Tuebingen, Germany
| | - Andrea Wenninger-Weinzierl
- Hertie Institute for Clinical Brain Research and German Center for Neurodegenerative Diseases, University Clinic Tuebingen, Tuebingen, Germany
| | - Ralf Kühn
- Max-Delbrueck-Center for Moleculare Medizin and Berlin Institute of Health, Berlin, Germany
- Helmholtz Zentrum Muenchen, Technical University Muenchen-Weihenstephan, Institute of Developmental Genetics, Neuherberg, Germany
| | - Daniela Vogt-Weisenhorn
- Helmholtz Zentrum Muenchen, Technical University Muenchen-Weihenstephan, Institute of Developmental Genetics, Neuherberg, Germany
| | - Florian Giesert
- Helmholtz Zentrum Muenchen, Technical University Muenchen-Weihenstephan, Institute of Developmental Genetics, Neuherberg, Germany
| | - Wolfgang Wurst
- Helmholtz Zentrum Muenchen, Technical University Muenchen-Weihenstephan, Institute of Developmental Genetics, Neuherberg, Germany
- German Center for Neurodegenerative Diseases, Munich, Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Thomas Gasser
- Hertie Institute for Clinical Brain Research and German Center for Neurodegenerative Diseases, University Clinic Tuebingen, Tuebingen, Germany
| | - Saskia Biskup
- Hertie Institute for Clinical Brain Research and German Center for Neurodegenerative Diseases, University Clinic Tuebingen, Tuebingen, Germany.
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Walker MD, Volta M, Cataldi S, Dinelle K, Beccano-Kelly D, Munsie L, Kornelsen R, Mah C, Chou P, Co K, Khinda J, Mroczek M, Bergeron S, Yu K, Cao LP, Funk N, Ott T, Galter D, Riess O, Biskup S, Milnerwood AJ, Stoessl AJ, Farrer MJ, Sossi V. Behavioral deficits and striatal DA signaling in LRRK2 p.G2019S transgenic rats: a multimodal investigation including PET neuroimaging. J Parkinsons Dis 2015; 4:483-98. [PMID: 25000966 DOI: 10.3233/jpd-140344] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND A major risk-factor for developing Parkinson's disease (PD) is genetic variability in leucine-rich repeat kinase 2 (LRRK2), most notably the p.G2019S mutation. Examination of the effects of this mutation is necessary to determine the etiology of PD and to guide therapeutic development. OBJECTIVE Assess the behavioral consequences of LRRK2 p.G2019S overexpression in transgenic rats as they age and test the functional integrity of the nigro-striatal dopamine system. Conduct positron emission tomography (PET) neuroimaging to compare transgenic rats with previous data from human LRRK2 mutation carriers. METHODS Rats overexpressing human LRRK2 p.G2019S were generated by BAC transgenesis and compared to non-transgenic (NT) littermates. Motor skill tests were performed at 3, 6 and 12 months-of-age. PET, performed at 12 months, assessed the density of dopamine and vesicular monoamine transporters (DAT and VMAT2, respectively) and measured dopamine synthesis, storage and availability. Brain tissue was assayed for D2, DAT, dopamine and cAMP-regulated phosphoprotein (DARPP32) and tyrosine hydroxylase (TH) expression by Western blot, and TH by immunohistochemistry. RESULTS Transgenic rats had no abnormalities in measures of striatal dopamine function at 12 months. A behavioral phenotype was present, with LRRK2 p.G2019S rats performing significantly worse on the rotarod than non-transgenic littermates (26% reduction in average running duration at 6 months), but with normal performance in other motor tests. CONCLUSIONS Neuroimaging using dopaminergic PET did not recapitulate prior studies in human LRRK2 mutation carriers. Consistently, LRRK2 p.G2019S rats do not develop overt neurodegeneration; however, they do exhibit behavioral abnormalities.
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Affiliation(s)
- Matthew D Walker
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
| | - Mattia Volta
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Stefano Cataldi
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Katherine Dinelle
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Dayne Beccano-Kelly
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Lise Munsie
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Rick Kornelsen
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Chenoa Mah
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Patrick Chou
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Kimberley Co
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Jaskaran Khinda
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Marta Mroczek
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Sabrina Bergeron
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Katrina Yu
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Li Ping Cao
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Natalja Funk
- Department of Neurodegeneration, Hertie Institute for Clinical Brain Research and German Center for Neurodegenerative Diseases DZNE, Tübingen, Germany
| | - Thomas Ott
- Department of Medical Genetics, University of Tübingen, Tübingen, Germany
| | - Dagmar Galter
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Olaf Riess
- Department of Medical Genetics, University of Tübingen, Tübingen, Germany
| | - Saskia Biskup
- Department of Neurodegeneration, Hertie Institute for Clinical Brain Research and German Center for Neurodegenerative Diseases DZNE, Tübingen, Germany
| | - Austen J Milnerwood
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - A Jon Stoessl
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, BC, Canada Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Matthew J Farrer
- Centre for Applied Neurogenetics, Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Vesna Sossi
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada
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Garcia-Miralles M, Coomaraswamy J, Häbig K, Herzig MC, Funk N, Gillardon F, Maisel M, Jucker M, Gasser T, Galter D, Biskup S. No dopamine cell loss or changes in cytoskeleton function in transgenic mice expressing physiological levels of wild type or G2019S mutant LRRK2 and in human fibroblasts. PLoS One 2015; 10:e0118947. [PMID: 25830304 PMCID: PMC4382199 DOI: 10.1371/journal.pone.0118947] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 01/14/2015] [Indexed: 11/25/2022] Open
Abstract
Mutations within the LRRK2 gene have been identified in Parkinson’s disease (PD) patients and have been implicated in the dysfunction of several cellular pathways. Here, we explore how pathogenic mutations and the inhibition of LRRK2 kinase activity affect cytoskeleton dynamics in mouse and human cell systems. We generated and characterized a novel transgenic mouse model expressing physiological levels of human wild type and G2019S-mutant LRRK2. No neuronal loss or neurodegeneration was detected in midbrain dopamine neurons at the age of 12 months. Postnatal hippocampal neurons derived from transgenic mice showed no alterations in the seven parameters examined concerning neurite outgrowth sampled automatically on several hundred neurons using high content imaging. Treatment with the kinase inhibitor LRRK2-IN-1 resulted in no significant changes in the neurite outgrowth. In human fibroblasts we analyzed whether pathogenic LRRK2 mutations change cytoskeleton functions such as cell adhesion. To this end we compared the adhesion characteristics of human skin fibroblasts derived from six PD patients carrying one of three different pathogenic LRRK2 mutations and from four age-matched control individuals. The mutant LRRK2 variants as well as the inhibition of LRRK2 kinase activity did not reveal any significant cell adhesion differences in cultured fibroblasts. In summary, our results in both human and mouse cell systems suggest that neither the expression of wild type or mutant LRRK2, nor the inhibition of LRRK2 kinase activity affect neurite complexity and cellular adhesion.
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Affiliation(s)
- Marta Garcia-Miralles
- Department of Neurodegeneration, Hertie-Institute for Clinical Brain Research and DZNE, German Center for Neurodegenerative Diseases, 72076 Tuebingen, Germany
| | - Janaky Coomaraswamy
- Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research and DZNE, German Center for Neurodegenerative Diseases, 72076 Tuebingen, Germany
| | - Karina Häbig
- Department of Medical Genetics and Applied Genomics, Institute of Human Genetics, University of Tuebingen, 72076 Tuebingen, Germany
| | - Martin C. Herzig
- Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research and DZNE, German Center for Neurodegenerative Diseases, 72076 Tuebingen, Germany
| | - Natalja Funk
- Department of Neurodegeneration, Hertie-Institute for Clinical Brain Research and DZNE, German Center for Neurodegenerative Diseases, 72076 Tuebingen, Germany
| | - Frank Gillardon
- Boehringer Ingelheim Pharma GmbH & Co. KG, CNS Research, 88397 Biberach an der Riss, Germany
| | - Martina Maisel
- Department of Neurodegeneration, Hertie-Institute for Clinical Brain Research and DZNE, German Center for Neurodegenerative Diseases, 72076 Tuebingen, Germany
| | - Mathias Jucker
- Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research and DZNE, German Center for Neurodegenerative Diseases, 72076 Tuebingen, Germany
| | - Thomas Gasser
- Department of Neurodegeneration, Hertie-Institute for Clinical Brain Research and DZNE, German Center for Neurodegenerative Diseases, 72076 Tuebingen, Germany
| | - Dagmar Galter
- Department of Neuroscience, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Saskia Biskup
- Department of Neurodegeneration, Hertie-Institute for Clinical Brain Research and DZNE, German Center for Neurodegenerative Diseases, 72076 Tuebingen, Germany
- * E-mail:
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Funk N, Wieghofer P, Grimm S, Schaefer R, Bühring HJ, Gasser T, Biskup S. Characterization of peripheral hematopoietic stem cells and monocytes in Parkinson's disease. Mov Disord 2013; 28:392-5. [PMID: 23401086 DOI: 10.1002/mds.25300] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Revised: 10/20/2012] [Accepted: 10/31/2012] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Emerging evidence has highlighted the pivotal role of the immune system in neurodegenerative diseases. This study investigated the impact of progressive neurodegeneration on the differentiation and development of hematopoietic stem cells in the peripheral blood of Parkinson's patients. METHODS A colony-forming cell assay was established to study hematopoietic stem cells from venous blood of Parkinson's patients, and flow cytometry was used to analyze the expression of chemokine receptors on monocytes. RESULTS We demonstrate that there is strong upregulation in the percentage of monocyte precursors in the peripheral blood of Parkinson's patients and asymptomatic high-risk individuals. We identify the receptor CCR2 as undergoing strong upregulation on the surface of classical monocytes in Parkinson's patients. CONCLUSIONS The association between blood cell development and progressive cell death in the brain of Parkinson's patients should be further investigated as a potential dynamic biomarker and indicator of disease progression.
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Affiliation(s)
- Natalja Funk
- Hertie Institute for Clinical Brain Research and German Center for Neurodegenerative Diseases, Tuebingen, Germany
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6
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Glinka M, Herrmann T, Funk N, Havlicek S, Rossoll W, Winkler C, Sendtner M. The heterogeneous nuclear ribonucleoprotein-R is necessary for axonal β-actin mRNA translocation in spinal motor neurons. Hum Mol Genet 2010; 19:1951-66. [DOI: 10.1093/hmg/ddq073] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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Schwenkert I, Eltrop R, Funk N, Steinert JR, Schuster CM, Scholz H. The hangover gene negatively regulates bouton addition at the Drosophila neuromuscular junction. Mech Dev 2008; 125:700-11. [DOI: 10.1016/j.mod.2008.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Revised: 04/17/2008] [Accepted: 04/19/2008] [Indexed: 10/22/2022]
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Frebel K, Wiese S, Funk N, Pühringer D, Sendtner M. Differential modulation of neurite growth by the S- and the L-forms of bag1, a co-chaperone of Hsp70. NEURODEGENER DIS 2007; 4:261-9. [PMID: 17596720 DOI: 10.1159/000101850] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Bag1 acts as a cochaperone for Hsp70. However, it also binds to members of the RAF family and to Akt. In addition, bag1 and Hsp70 are part of a complex with glucocorticoid receptors and thus modulate glucocorticoid receptor-mediated transcriptional activation. In the developing nervous system, bag1 is expressed in at least two isoforms. The L-form (bag1L) contains a nuclear localization signal and thus can translocate to the nucleus. In contrast, the S-form (bag1S) is localized exclusively in the cytoplasm. Former studies have shown that B-RAF is essential for neurotrophin-mediated survival signaling in motoneurons and sensory neurons, and that bag1 plays a role in coordinating B-RAF and Akt function in this context. In the absence of B-RAF, embryonic motoneurons and sensory neurons are not able to survive, indicating that bag1 and B-RAF are essential mediators for neuronal survival in response to neurotrophic factors during development. However, the role of the complex containing bag1, Hsp70 and B-RAF in mediating neurite growth in response to neurotrophic factors remained unclear. We have therefore studied the effect of bag1 overexpression in rat phaeochromocytoma (PC12) cells. Upon NGF treatment, proliferating PC12 become postmitotic and grow out neuronal processes. Bag1S overexpression interferes with neurite extension in PC12 cells. In contrast, bag1L does not disturb neurite outgrowth. Interaction of bag1S with Hsp70 appears necessary for this effect. These data indicate that the cytosolic form of bag1 participates in neurotrophin-mediated neurite growth, and that interaction with Hsp70 plays a crucial role in this context.
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Affiliation(s)
- Karin Frebel
- Institute for Clinical Neurobiology, University of Würzburg, Würzburg, Germany
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9
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Bender FLP, Fischer M, Funk N, Orel N, Rethwilm A, Sendtner M. High-efficiency gene transfer into cultured embryonic motoneurons using recombinant lentiviruses. Histochem Cell Biol 2006; 127:439-48. [PMID: 17102992 DOI: 10.1007/s00418-006-0247-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2006] [Indexed: 10/23/2022]
Abstract
Primary neurons are a common tool for investigating gene function for survival and morphological and functional differentiation. Gene transfer techniques play an important role in this context. However, the efficacy of conventional gene transfer techniques, in particular for primary motoneurons is low so that it is not possible to distinguish whether the observed effects are representative for all neurons or only for the small subpopulation that expresses the transfected cDNA. In order to develop techniques that allow high gene transfer rates, we have optimized lentiviral-based gene transfer for cultured motoneurons by using a replication-defective viral vector system. These techniques result in transduction efficacies higher than 50%, as judged by EGFP expression under the control of SFFV or CMV promoters. Under the same conditions, survival and morphology of the cultured motoneurons was not altered, at least not when virus titers did not exceed a multiplicity of infection of 100. Under the same cell culture conditions, electroporation resulted in less than 5% transfected motoneurons and reduced survival. Therefore we consider this lentivirus-based gene transfer protocol as a suitable tool to study the effects of gene transfer on motoneuron survival, differentiation and function.
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Affiliation(s)
- Florian L P Bender
- Institute for Clinical Neurobiology, University of Wurzburg, Josef-Schneider-Str. 11, 97080, Wurzburg, Germany
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10
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Ito Y, Wiese S, Funk N, Chittka A, Rossoll W, Bömmel H, Watabe K, Wegner M, Sendtner M. Sox10 regulates ciliary neurotrophic factor gene expression in Schwann cells. Proc Natl Acad Sci U S A 2006; 103:7871-6. [PMID: 16684879 PMCID: PMC1472537 DOI: 10.1073/pnas.0602332103] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Ciliary neurotrophic factor (Cntf) plays an essential role in postnatal maintenance of spinal motoneurons. Whereas the expression of this neurotrophic factor is low during embryonic development, it is highly up-regulated after birth in myelinating Schwann cells of rodents. To characterize the underlying transcriptional mechanisms, we have analyzed and compared the effects of various glial transcription factors. In contrast to Pit-1, Oct-1, Unc-86 homology region (POU) domain class 3, transcription factor 1 (Oct6/SCIP/Tst-1) and paired box gene 3 (Pax3), SRY-box-containing gene 10 (Sox10) induces Cntf expression in Schwann cells. Subsequent promoter analysis using luciferase reporter gene and EMSA identified the corresponding response elements within the Cntf promoter. Overexpression of Sox10 in primary sciatic nerve Schwann cells leads to a >100-fold up-regulation of Cntf protein, and suppression of Sox10 by RNA interference in the spontaneously immortalized Schwann cell line 32 reduces Cntf expression by >80%. Mice with heterozygous inactivation of the Sox10 gene show significantly reduced Cntf protein levels in sciatic nerves, indicating that Sox10 is necessary and sufficient for regulating Cntf expression in the peripheral nervous system.
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Affiliation(s)
- Yasuhiro Ito
- *Institute for Clinical Neurobiology, University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Stefan Wiese
- *Institute for Clinical Neurobiology, University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Natalja Funk
- *Institute for Clinical Neurobiology, University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Alexandra Chittka
- *Institute for Clinical Neurobiology, University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Wilfried Rossoll
- *Institute for Clinical Neurobiology, University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Heike Bömmel
- *Institute for Clinical Neurobiology, University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Kazuhiko Watabe
- Department of Molecular Neuropathology, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashidai, Fuchu-shi, Tokyo 183-8526, Japan; and
| | - Michael Wegner
- Institute of Biochemistry, Erlangen University, D-91054 Erlangen, Germany
| | - Michael Sendtner
- *Institute for Clinical Neurobiology, University of Wuerzburg, D-97080 Wuerzburg, Germany
- To whom correspondence should be addressed at:
Institute for Clinical Neurobiology, Josef-Schneider-Strasse 11, University of Wuerzburg, D-97080 Wuerzburg, Germany. E-mail:
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Godenschwege TA, Reisch D, Diegelmann S, Eberle K, Funk N, Heisenberg M, Hoppe V, Hoppe J, Klagges BRE, Martin JR, Nikitina EA, Putz G, Reifegerste R, Reisch N, Rister J, Schaupp M, Scholz H, Schwärzel M, Werner U, Zars TD, Buchner S, Buchner E. Flies lacking all synapsins are unexpectedly healthy but are impaired in complex behaviour. Eur J Neurosci 2004; 20:611-22. [PMID: 15255973 DOI: 10.1111/j.1460-9568.2004.03527.x] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Vertebrate synapsins are abundant synaptic vesicle phosphoproteins that have been proposed to fine-regulate neurotransmitter release by phosphorylation-dependent control of synaptic vesicle motility. However, the consequences of a total lack of all synapsin isoforms due to a knock-out of all three mouse synapsin genes have not yet been investigated. In Drosophila a single synapsin gene encodes several isoforms and is expressed in most synaptic terminals. Thus the targeted deletion of the synapsin gene of Drosophila eliminates the possibility of functional knock-out complementation by other isoforms. Unexpectedly, synapsin null mutant flies show no obvious defects in brain morphology, and no striking qualitative changes in behaviour are observed. Ultrastructural analysis of an identified 'model' synapse of the larval nerve muscle preparation revealed no difference between wild-type and mutant, and spontaneous or evoked excitatory junction potentials at this synapse were normal up to a stimulus frequency of 5 Hz. However, when several behavioural responses were analysed quantitatively, specific differences between mutant and wild-type flies are noted. Adult locomotor activity, optomotor responses at high pattern velocities, wing beat frequency, and visual pattern preference are modified. Synapsin mutant flies show faster habituation of an olfactory jump response, enhanced ethanol tolerance, and significant defects in learning and memory as measured using three different paradigms. Larval behavioural defects are described in a separate paper. We conclude that Drosophila synapsins play a significant role in nervous system function, which is subtle at the cellular level but manifests itself in complex behaviour.
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Affiliation(s)
- Tanja A Godenschwege
- Theodor Boveri-Institut für Biowissenschaften, Lehrstuhl für Genetik und Neurobiologie, Am Hubland D-97074 Wuerzburg, Germany
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Funk N, Becker S, Huber S, Brunner M, Buchner E. Targeted mutagenesis of the Sap47 gene of Drosophila: flies lacking the synapse associated protein of 47 kDa are viable and fertile. BMC Neurosci 2004; 5:16. [PMID: 15117418 PMCID: PMC419347 DOI: 10.1186/1471-2202-5-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2003] [Accepted: 04/29/2004] [Indexed: 01/24/2023] Open
Abstract
Background Conserved proteins preferentially expressed in synaptic terminals of the nervous system are likely to play a significant role in brain function. We have previously identified and molecularly characterized the Sap47 gene which codes for a novel synapse associated protein of 47 kDa in Drosophila. Sequence comparison identifies homologous proteins in numerous species including C. elegans, fish, mouse and human. First hints as to the function of this novel protein family can be obtained by generating mutants for the Sap47 gene in Drosophila. Results Attempts to eliminate the Sap47 gene through targeted mutagenesis by homologous recombination were unsuccessful. However, several mutants were generated by transposon remobilization after an appropriate insertion line had become available from the Drosophila P-element screen of the Bellen/Hoskins/Rubin/Spradling labs. Characterization of various deletions in the Sap47 gene due to imprecise excision of the P-element identified three null mutants and three hypomorphic mutants. Null mutants are viable and fertile and show no gross structural or obvious behavioural deficits. For cell-specific over-expression and "rescue" of the knock-out flies a transgenic line was generated which expresses the most abundant transcript under the control of the yeast enhancer UAS. In addition, knock-down of the Sap47 gene was achieved by generating 31 transgenic lines expressing Sap47 RNAi constructs, again under UAS control. When driven by a ubiquitously expressed yeast transcription factor (GAL4), Sap47 gene suppression in several of these lines is highly efficient resulting in residual SAP47 protein concentrations in heads as low as 6% of wild type levels. Conclusion The conserved synaptic protein SAP47 of Drosophila is not essential for basic synaptic function. The Sap47 gene region may be refractory to targeted mutagenesis by homologous recombination. RNAi using a construct linking genomic DNA to anti-sense cDNA in our hands is not more effective than using a cDNA-anti-sense cDNA construct. The tools developed in this study will now allow a detailed analysis of the molecular, cellular and systemic function of the SAP47 protein in Drosophila.
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Affiliation(s)
- Natalja Funk
- Theodor Boveri-Institut für Biowissenschaften, Lehrstuhl für Genetik und Neurobiologie, Am Hubland D-97074 Würzburg, Germany
| | - Sonja Becker
- Theodor Boveri-Institut für Biowissenschaften, Lehrstuhl für Genetik und Neurobiologie, Am Hubland D-97074 Würzburg, Germany
- Institut für Experimentelle Genetik, GSF - Forschungszentrum für Gesundheit und Umwelt, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Saskia Huber
- Theodor Boveri-Institut für Biowissenschaften, Lehrstuhl für Genetik und Neurobiologie, Am Hubland D-97074 Würzburg, Germany
- Institut für Humangenetik, GSF - Forschungszentrum für Gesundheit und Umwelt, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Marion Brunner
- Theodor Boveri-Institut für Biowissenschaften, Lehrstuhl für Genetik und Neurobiologie, Am Hubland D-97074 Würzburg, Germany
| | - Erich Buchner
- Theodor Boveri-Institut für Biowissenschaften, Lehrstuhl für Genetik und Neurobiologie, Am Hubland D-97074 Würzburg, Germany
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Friess H, Beger HG, Kunz J, Funk N, Schilling M, Büchler MW. Treatment of advanced pancreatic cancer with mistletoe: results of a pilot trial. Anticancer Res 1996; 16:915-20. [PMID: 8687151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Pancreatic cancer is a devastating disease with poor prognosis. It is characterized by its unresponsiveness to chemo- and/or radiotherapy. Therefore, many patients demand alternative drug therapy such as mistletoe treatment. However, there are no controlled data available analyzing the effect of mistletoe treatment in pancreatic cancer. In the present phase I/II study we evaluated the effect of mistletoe (Eurixor) treatment in 16 patients (7 women, 9 men) with histologically verified ductal pancreatic carcinoma. At the time when the patients were enrolled nine patients had lymph node metastases (stage III), and in 7 patients distant metastases (stage IV) were present. Mistletoe was administered twice a week by subcutaneous injection in a dosage of 1 ng per kg body weight. Monthly follow-ups included clinical status, multidimensional evaluation of quality of life, contrast enhanced computed axial tomography scan (CT scan) or ultrasonography, and determination of the tumor markers carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9). Apart from one anaphylactic reaction, which necessitated suspension of treatment for a few days, no severe side effects were observed. No partial or complete remission was seen. Eight patients (50%) showed a CT-verified status of "no change" according to World Health Organization criteria for at least 8 weeks. Median survival time in all patients was 5.6 months (range 1.5 to 26.5 months). Analysis of multidimensional evaluation of quality of life showed a stable course of disease in 7 patients. All except two patients claimed that mistletoe had a positive effect on their quality of life, with an obvious decline only during the last weeks of life. These results indicate that mistletoe is not able to significantly influence tumor growth in advanced pancreatic carcinomas. However, mistletoe treatment can stabilize quality of life, and therefore may help patients to maintain adequate life quality in their few remaining months.
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Affiliation(s)
- H Friess
- Department of Visceral and Transplantation Surgery, University of Bern, Switzerland
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Funk N. Abortion counselling and the 1995 German abortion law. Conn J Int Law 1996; 12:33-65. [PMID: 16506337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Affiliation(s)
- N Funk
- Department of Philosophy, Brooklyn College, City University of New York, USA
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Ackermann K, Funk N, Fürg N. [Statistical results of the treatment of carcinoma of the mouth]. Dtsch Z Mund Kiefer Gesichtschir 1985; 9:455-60. [PMID: 3869489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Dielert E, Funk N. [Precision of oral cytodiagnosis]. Zahnarztl Prax 1983; 34:326-31. [PMID: 6582732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Funk N. [Occlusion as the main symptom of mid-face fracture. Case report]. Zahnarzt 1982; 26:81-4. [PMID: 6950622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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