101
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Wlaschin JJ, Gluski JM, Nguyen E, Silberberg H, Thompson JH, Chesler AT, Le Pichon CE. Dual leucine zipper kinase is required for mechanical allodynia and microgliosis after nerve injury. eLife 2018; 7:33910. [PMID: 29968565 PMCID: PMC6029846 DOI: 10.7554/elife.33910] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 06/10/2018] [Indexed: 12/17/2022] Open
Abstract
Neuropathic pain resulting from nerve injury can become persistent and difficult to treat but the molecular signaling responsible for its development remains poorly described. Here, we identify the neuronal stress sensor dual leucine zipper kinase (DLK; Map3k12) as a key molecule controlling the maladaptive pathways that lead to pain following injury. Genetic or pharmacological inhibition of DLK reduces mechanical hypersensitivity in a mouse model of neuropathic pain. Furthermore, DLK inhibition also prevents the spinal cord microgliosis that results from nerve injury and arises distant from the injury site. These striking phenotypes result from the control by DLK of a transcriptional program in somatosensory neurons regulating the expression of numerous genes implicated in pain pathogenesis, including the immune gene Csf1. Thus, activation of DLK is an early event, or even the master regulator, controlling a wide variety of pathways downstream of nerve injury that ultimately lead to chronic pain.
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Affiliation(s)
- Josette J Wlaschin
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Jacob M Gluski
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Eileen Nguyen
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, United States
| | - Hanna Silberberg
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - James H Thompson
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, United States
| | - Alexander T Chesler
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, United States
| | - Claire E Le Pichon
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
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102
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The Heterochronic Gene lin-14 Controls Axonal Degeneration in C. elegans Neurons. Cell Rep 2018; 20:2955-2965. [PMID: 28930688 DOI: 10.1016/j.celrep.2017.08.083] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 07/31/2017] [Accepted: 08/25/2017] [Indexed: 01/23/2023] Open
Abstract
The disproportionate length of an axon makes its structural and functional maintenance a major task for a neuron. The heterochronic gene lin-14 has previously been implicated in regulating the timing of key developmental events in the nematode C. elegans. Here, we report that LIN-14 is critical for maintaining neuronal integrity. Animals lacking lin-14 display axonal degeneration and guidance errors in both sensory and motor neurons. We demonstrate that LIN-14 functions both cell autonomously within the neuron and non-cell autonomously in the surrounding tissue, and we show that interaction between the axon and its surrounding tissue is essential for the preservation of axonal structure. Furthermore, we demonstrate that lin-14 expression is only required during a short period early in development in order to promote axonal maintenance throughout the animal's life. Our results identify a crucial role for LIN-14 in preventing axonal degeneration and in maintaining correct interaction between an axon and its surrounding tissue.
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103
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Kawasaki A, Okada M, Tamada A, Okuda S, Nozumi M, Ito Y, Kobayashi D, Yamasaki T, Yokoyama R, Shibata T, Nishina H, Yoshida Y, Fujii Y, Takeuchi K, Igarashi M. Growth Cone Phosphoproteomics Reveals that GAP-43 Phosphorylated by JNK Is a Marker of Axon Growth and Regeneration. iScience 2018; 4:190-203. [PMID: 30240740 PMCID: PMC6147025 DOI: 10.1016/j.isci.2018.05.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/05/2018] [Accepted: 05/25/2018] [Indexed: 12/20/2022] Open
Abstract
Neuronal growth cones are essential for nerve growth and regeneration, as well as for the formation and rearrangement of the neural network. To elucidate phosphorylation-dependent signaling pathways and establish useful molecular markers for axon growth and regeneration, we performed a phosphoproteomics study of mammalian growth cones, which identified >30,000 phosphopeptides of ∼1,200 proteins. The phosphorylation sites were highly proline directed and primarily MAPK dependent, owing to the activation of JNK, suggesting that proteins that undergo proline-directed phosphorylation mediate nerve growth in the mammalian brain. Bioinformatics analysis revealed that phosphoproteins were enriched in microtubules and the cortical cytoskeleton. The most frequently phosphorylated site was S96 of GAP-43 (growth-associated protein 43-kDa), a vertebrate-specific protein involved in axon growth. This previously uncharacterized phosphorylation site was JNK dependent. S96 phosphorylation was specifically detected in growing and regenerating axons as the most frequent target of JNK signaling; thus it represents a promising new molecular marker for mammalian axonal growth and regeneration. Phosphoproteomics of mammalian growth cone membranes reveals activation of MAPK JNK is the activated MAPK in growth cones and phosphorylates S96 of GAP-43 pS96 of GAP-43, the most frequent site, is observed in growing axons pS96 is biochemically detected in the regenerating axons of the peripheral nerves
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Affiliation(s)
- Asami Kawasaki
- Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata 951-8510, Japan; Center for Trans-disciplinary Research, Institute for Research Promotion, Niigata University, Chuo-ku, Niigata 951-8510, Japan
| | - Masayasu Okada
- Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata 951-8510, Japan; Center for Trans-disciplinary Research, Institute for Research Promotion, Niigata University, Chuo-ku, Niigata 951-8510, Japan; Department of Neurosurgery, Brain Research Institute, Niigata University, Chuo-ku, Niigata 951-8585, Japan
| | - Atsushi Tamada
- Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata 951-8510, Japan; Center for Trans-disciplinary Research, Institute for Research Promotion, Niigata University, Chuo-ku, Niigata 951-8510, Japan; Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Shujiro Okuda
- Laboratory of Bioinformatics, Graduate School of Medical and Dental Sciences, Niigata University, Chuo-ku, Niigata 951-8510, Japan
| | - Motohiro Nozumi
- Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata 951-8510, Japan; Center for Trans-disciplinary Research, Institute for Research Promotion, Niigata University, Chuo-ku, Niigata 951-8510, Japan
| | - Yasuyuki Ito
- Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata 951-8510, Japan
| | - Daiki Kobayashi
- Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata 951-8510, Japan
| | - Tokiwa Yamasaki
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Ryo Yokoyama
- K.K. Sciex Japan, Shinagawa-ku, Tokyo 140-0001, Japan
| | | | - Hiroshi Nishina
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Yutaka Yoshida
- Center for Coordination of Research, Institute for Research Promotion, Niigata University, Ikarashi, Niigata 951-2181, Japan
| | - Yukihiko Fujii
- Department of Neurosurgery, Brain Research Institute, Niigata University, Chuo-ku, Niigata 951-8585, Japan
| | - Kosei Takeuchi
- Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata 951-8510, Japan; Center for Trans-disciplinary Research, Institute for Research Promotion, Niigata University, Chuo-ku, Niigata 951-8510, Japan; Department of Medical Cell Biology, Aichi Medical University, Nagakute, Aichi 480-1195, Japan
| | - Michihiro Igarashi
- Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University, 1-757 Asahimachi, Chuo-ku, Niigata 951-8510, Japan; Center for Trans-disciplinary Research, Institute for Research Promotion, Niigata University, Chuo-ku, Niigata 951-8510, Japan.
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104
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Distinct homeostatic modulations stabilize reduced postsynaptic receptivity in response to presynaptic DLK signaling. Nat Commun 2018; 9:1856. [PMID: 29748610 PMCID: PMC5945772 DOI: 10.1038/s41467-018-04270-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 04/16/2018] [Indexed: 11/08/2022] Open
Abstract
Synapses are constructed with the stability to last a lifetime, yet sufficiently flexible to adapt during injury. Although fundamental pathways that mediate intrinsic responses to neuronal injury have been defined, less is known about how synaptic partners adapt. We have investigated responses in the postsynaptic cell to presynaptic activation of the injury-related Dual Leucine Zipper Kinase pathway at the Drosophila neuromuscular junction. We find that the postsynaptic compartment reduces neurotransmitter receptor levels, thus depressing synaptic strength. Interestingly, this diminished state is stabilized through distinct modulations to two postsynaptic homeostatic signaling systems. First, a retrograde response normally triggered by reduced receptor levels is silenced, preventing a compensatory enhancement in presynaptic neurotransmitter release. However, when global presynaptic release is attenuated, a postsynaptic receptor scaling mechanism persists to adaptively stabilize this diminished neurotransmission state. Thus, the homeostatic set point of synaptic strength is recalibrated to a reduced state as synapses acclimate to injury.
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105
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Murillo B, Mendes Sousa M. Neuronal Intrinsic Regenerative Capacity: The Impact of Microtubule Organization and Axonal Transport. Dev Neurobiol 2018; 78:952-959. [PMID: 29738096 DOI: 10.1002/dneu.22602] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 04/20/2018] [Accepted: 04/25/2018] [Indexed: 11/06/2022]
Abstract
In the adult vertebrate central nervous system, axons generally fail to regenerate. In contrast, peripheral nervous system axons are able to form a growth cone and regenerate upon lesion. Among the multiple intrinsic mechanisms leading to the formation of a new growth cone and to successful axon regrowth, cytoskeleton organization and dynamics is central. Here we discuss how multiple pathways that define the regenerative capacity converge into the regulation of the axonal microtubule cytoskeleton and transport. We further explore the use of dorsal root ganglion neurons as a model to study the neuronal regenerative ability. Finally, we address some of the unanswered questions in the field, including the mechanisms by which axonal transport might be modulated by injury, and the relationship between microtubule organization, dynamics, and axonal transport. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 00: 000-000, 2018.
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Affiliation(s)
- Blanca Murillo
- Nerve Regeneration group, Instituto de Biologia Molecular e Celular - IBMC and Instituto de Inovação e Investigação em Saúde, University of Porto, Rua Alfredo Allen 208, Porto, 4200-135, Portugal
| | - Mónica Mendes Sousa
- Nerve Regeneration group, Instituto de Biologia Molecular e Celular - IBMC and Instituto de Inovação e Investigação em Saúde, University of Porto, Rua Alfredo Allen 208, Porto, 4200-135, Portugal
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106
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Le Pichon CE, Meilandt WJ, Dominguez S, Solanoy H, Lin H, Ngu H, Gogineni A, Sengupta Ghosh A, Jiang Z, Lee SH, Maloney J, Gandham VD, Pozniak CD, Wang B, Lee S, Siu M, Patel S, Modrusan Z, Liu X, Rudhard Y, Baca M, Gustafson A, Kaminker J, Carano RAD, Huang EJ, Foreman O, Weimer R, Scearce-Levie K, Lewcock JW. Loss of dual leucine zipper kinase signaling is protective in animal models of neurodegenerative disease. Sci Transl Med 2018; 9:9/403/eaag0394. [PMID: 28814543 DOI: 10.1126/scitranslmed.aag0394] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 11/23/2016] [Accepted: 03/27/2017] [Indexed: 12/16/2022]
Abstract
Hallmarks of chronic neurodegenerative disease include progressive synaptic loss and neuronal cell death, yet the cellular pathways that underlie these processes remain largely undefined. We provide evidence that dual leucine zipper kinase (DLK) is an essential regulator of the progressive neurodegeneration that occurs in amyotrophic lateral sclerosis and Alzheimer's disease. We demonstrate that DLK/c-Jun N-terminal kinase signaling was increased in mouse models and human patients with these disorders and that genetic deletion of DLK protected against axon degeneration, neuronal loss, and functional decline in vivo. Furthermore, pharmacological inhibition of DLK activity was sufficient to attenuate the neuronal stress response and to provide functional benefit even in the presence of ongoing disease. These findings demonstrate that pathological activation of DLK is a conserved mechanism that regulates neurodegeneration and suggest that DLK inhibition may be a potential approach to treat multiple neurodegenerative diseases.
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Affiliation(s)
- Claire E Le Pichon
- Department of Neuroscience, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - William J Meilandt
- Department of Neuroscience, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA.
| | - Sara Dominguez
- Department of Neuroscience, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Hilda Solanoy
- Department of Neuroscience, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Han Lin
- Department of Neuroscience, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Hai Ngu
- Department of Pathology, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Alvin Gogineni
- Department of Biomedical Imaging, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | | | - Zhiyu Jiang
- Department of Neuroscience, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Seung-Hye Lee
- Department of Neuroscience, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Janice Maloney
- Department of Neuroscience, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Vineela D Gandham
- Department of Biomedical Imaging, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Christine D Pozniak
- Department of Neuroscience, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Bei Wang
- Department of Neuroscience, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Sebum Lee
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Michael Siu
- Department of Discovery Chemistry, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Snahel Patel
- Department of Discovery Chemistry, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Zora Modrusan
- Department of Molecular Biology, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Xingrong Liu
- Department of Drug Metabolism and Pharmacokinetics, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - York Rudhard
- In Vitro Pharmacology, Evotec AG, Manfred Eigen Campus, 22419 Hamburg, Germany
| | - Miriam Baca
- Department of Pathology, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Amy Gustafson
- Department of Biochemical and Cellular Pharmacology, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Josh Kaminker
- Department of Bioinformatics, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Richard A D Carano
- Department of Biomedical Imaging, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Eric J Huang
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94143, USA.,Pathology Service 113B, San Francisco Veterans Affairs Medical Center, San Francisco, CA 94121, USA
| | - Oded Foreman
- Department of Pathology, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Robby Weimer
- Department of Biomedical Imaging, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Kimberly Scearce-Levie
- Department of Neuroscience, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Joseph W Lewcock
- Department of Neuroscience, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA.
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107
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Chen L. Microtubules and axon regeneration in C. elegans. Mol Cell Neurosci 2018; 91:160-166. [PMID: 29551667 DOI: 10.1016/j.mcn.2018.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 03/14/2018] [Accepted: 03/15/2018] [Indexed: 11/28/2022] Open
Abstract
Axon regeneration is a fundamental and conserved process that allows the nervous system to repair circuits after trauma. Due to its conserved genome, transparent body, and relatively simple neuroanatomy, C. elegans has become a powerful model organism for studying the cellular and molecular mechanisms underlying axon regeneration. Various studies from different model organisms have found microtubule dynamics to be pivotal to axon regrowth. In this review, we will discuss the latest findings on how microtubule dynamics are regulated during axon regeneration in C. elegans. Understanding the mechanisms of axon regeneration will aid in the development of more effective therapeutic strategies for treatments of diseases involving disconnection of axons, such as spinal cord injury and stroke.
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Affiliation(s)
- Lizhen Chen
- Barshop Institute for Longevity and Aging Studies, Department of Cell Systems and Anatomy, Department of Molecular Medicine, University of Texas Health Science Center San Antonio, San Antonio, TX, USA.
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108
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Koch M, Nicolas M, Zschaetzsch M, de Geest N, Claeys A, Yan J, Morgan MJ, Erfurth ML, Holt M, Schmucker D, Hassan BA. A Fat-Facets-Dscam1-JNK Pathway Enhances Axonal Growth in Development and after Injury. Front Cell Neurosci 2018; 11:416. [PMID: 29472843 PMCID: PMC5809495 DOI: 10.3389/fncel.2017.00416] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/12/2017] [Indexed: 11/13/2022] Open
Abstract
Injury to the adult central nervous systems (CNS) can result in severe long-term disability because damaged CNS connections fail to regenerate after trauma. Identification of regulators that enhance the intrinsic growth capacity of severed axons is a first step to restore function. Here, we conducted a gain-of-function genetic screen in Drosophila to identify strong inducers of axonal growth after injury. We focus on a novel axis the Down Syndrome Cell Adhesion Molecule (Dscam1), the de-ubiquitinating enzyme Fat Facets (Faf)/Usp9x and the Jun N-Terminal Kinase (JNK) pathway transcription factor Kayak (Kay)/Fos. Genetic and biochemical analyses link these genes in a common signaling pathway whereby Faf stabilizes Dscam1 protein levels, by acting on the 3'-UTR of its mRNA, and Dscam1 acts upstream of the growth-promoting JNK signal. The mammalian homolog of Faf, Usp9x/FAM, shares both the regenerative and Dscam1 stabilizing activities, suggesting a conserved mechanism.
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Affiliation(s)
- Marta Koch
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium
| | - Maya Nicolas
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium
| | - Marlen Zschaetzsch
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium
| | - Natalie de Geest
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium
| | - Annelies Claeys
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium
| | - Jiekun Yan
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium
| | - Matthew J Morgan
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium
| | - Maria-Luise Erfurth
- Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium.,Neuronal Wiring Lab, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Matthew Holt
- Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium.,Laboratory of Glia Biology, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Dietmar Schmucker
- Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium.,Neuronal Wiring Lab, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium
| | - Bassem A Hassan
- Laboratory of Neurogenetics, Center for Brain and Disease Research, Vlaams Instituut voor Biotechnologie (VIB), Leuven, Belgium.,Center for Human Genetics, University of Leuven School of Medicine, KU Leuven, Leuven, Belgium.,Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Institut du Cerveau et de la Moelle Epinière, Hôpital Pitié-Salpêtrière, UPMC, Sorbonne Universités, Paris, France
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109
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Lou WPK, Mateos A, Koch M, Klussman S, Yang C, Lu N, Kumar S, Limpert S, Göpferich M, Zschaetzsch M, Sliwinski C, Kenzelmann M, Seedorf M, Maillo C, Senis E, Grimm D, Puttagunta R, Mendez R, Liu K, Hassan BA, Martin-Villalba A. Regulation of Adult CNS Axonal Regeneration by the Post-transcriptional Regulator Cpeb1. Front Mol Neurosci 2018; 10:445. [PMID: 29379413 PMCID: PMC5770975 DOI: 10.3389/fnmol.2017.00445] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 12/20/2017] [Indexed: 12/19/2022] Open
Abstract
Adult mammalian central nervous system (CNS) neurons are unable to regenerate following axonal injury, leading to permanent functional impairments. Yet, the reasons underlying this regeneration failure are not fully understood. Here, we studied the transcriptome and translatome shortly after spinal cord injury. Profiling of the total and ribosome-bound RNA in injured and naïve spinal cords identified a substantial post-transcriptional regulation of gene expression. In particular, transcripts associated with nervous system development were down-regulated in the total RNA fraction while remaining stably loaded onto ribosomes. Interestingly, motif association analysis of post-transcriptionally regulated transcripts identified the cytoplasmic polyadenylation element (CPE) as enriched in a subset of these transcripts that was more resistant to injury-induced reduction at the transcriptome level. Modulation of these transcripts by overexpression of the CPE binding protein, Cpeb1, in mouse and Drosophila CNS neurons promoted axonal regeneration following injury. Our study uncovered a global evolutionarily conserved post-transcriptional mechanism enhancing regeneration of injured CNS axons.
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Affiliation(s)
- Wilson Pak-Kin Lou
- Division of Molecular Neurobiology, German Cancer Research Center, Heidelberg, Germany
- Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany
| | - Alvaro Mateos
- Division of Molecular Neurobiology, German Cancer Research Center, Heidelberg, Germany
| | - Marta Koch
- VIB Center for the Biology of Disease and Center for Human Genetics, VIB and KU Leuven, Leuven, Belgium
| | - Stefan Klussman
- Division of Molecular Neurobiology, German Cancer Research Center, Heidelberg, Germany
- Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany
| | - Chao Yang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, Hong Kong
| | - Na Lu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, Hong Kong
| | - Sachin Kumar
- Division of Molecular Neurobiology, German Cancer Research Center, Heidelberg, Germany
- Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany
| | - Stefanie Limpert
- Division of Molecular Neurobiology, German Cancer Research Center, Heidelberg, Germany
| | - Manuel Göpferich
- Division of Molecular Neurobiology, German Cancer Research Center, Heidelberg, Germany
- Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany
| | - Marlen Zschaetzsch
- VIB Center for the Biology of Disease and Center for Human Genetics, VIB and KU Leuven, Leuven, Belgium
| | - Christopher Sliwinski
- Department of Neuroregeneration, University Hospital Heidelberg, Heidelberg, Germany
| | - Marc Kenzelmann
- Division of Molecular Biology of the Cell I, German Cancer Research Center, Heidelberg, Germany
| | - Matthias Seedorf
- Zentrum für Molekulare Biologie, University of Heidelberg, Heidelberg, Germany
| | - Carlos Maillo
- Translational Control of Cell Cycle and Differentiation, Institute for Research in Biomedicine, Barcelona, Spain
| | - Elena Senis
- Virus Host Interaction, Heidelberg University Hospital, Center for Infectious Diseases/Virology, Cluster of Excellence CellNetworks, BioQuant, Heidelberg, Germany
| | - Dirk Grimm
- Virus Host Interaction, Heidelberg University Hospital, Center for Infectious Diseases/Virology, Cluster of Excellence CellNetworks, BioQuant, Heidelberg, Germany
| | - Radhika Puttagunta
- Department of Neuroregeneration, University Hospital Heidelberg, Heidelberg, Germany
| | - Raul Mendez
- Translational Control of Cell Cycle and Differentiation, Institute for Research in Biomedicine, Barcelona, Spain
| | - Kai Liu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, Hong Kong
- Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Hong Kong, Hong Kong
| | - Bassem A. Hassan
- VIB Center for the Biology of Disease and Center for Human Genetics, VIB and KU Leuven, Leuven, Belgium
- Sorbonne Universités, UPMC Univ Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et de la Moelle epiniere - Hôpital Pitié-Salpêtrière, Paris, France
| | - Ana Martin-Villalba
- Division of Molecular Neurobiology, German Cancer Research Center, Heidelberg, Germany
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Vibert L, Daulny A, Jarriault S. Wound healing, cellular regeneration and plasticity: the elegans way. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2018; 62:491-505. [PMID: 29938761 PMCID: PMC6161810 DOI: 10.1387/ijdb.180123sj] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Regeneration and wound healing are complex processes that allow organs and tissues to regain their integrity and functionality after injury. Wound healing, a key property of epithelia, involves tissue closure that in some cases leads to scar formation. Regeneration, a process rather limited in mammals, is the capacity to regrow (parts of) an organ or a tissue, after damage or amputation. What are the properties of organs and the features of tissue permitting functional regrowth and repair? What are the cellular and molecular mechanisms underlying these processes? These questions are crucial both in fundamental and applied contexts, with important medical implications. The mechanisms and cells underlying tissue repair have thus been the focus of intense investigation. The last decades have seen rapid progress in the domain and new models emerging. Here, we review the fundamental advances and the perspectives that the use of C. elegans as a model have brought to the mechanisms of wound healing and cellular plasticity, axon regeneration and transdifferentiation in vivo.
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Affiliation(s)
- Laura Vibert
- Department of Development and Stem Cells, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), CNRS UMR 7104/INSERM U1258, Université de Strasbourg, Strasbourg, France
| | - Anne Daulny
- Department of Development and Stem Cells, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), CNRS UMR 7104/INSERM U1258, Université de Strasbourg, Strasbourg, France
| | - Sophie Jarriault
- Department of Development and Stem Cells, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), CNRS UMR 7104/INSERM U1258, Université de Strasbourg, Strasbourg, France
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111
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An S, Zhou M, Li Z, Feng M, Cao G, Lu S, Liu L. Administration of CoCl 2 Improves Functional Recovery in a Rat Model of Sciatic Nerve Transection Injury. Int J Med Sci 2018; 15:1423-1432. [PMID: 30443161 PMCID: PMC6216053 DOI: 10.7150/ijms.27867] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 08/29/2018] [Indexed: 12/28/2022] Open
Abstract
Peripheral nerve injury is known to activate the hypoxia-inducible factor-1α (HIF-1α) pathway as one of pro-regenerative transcriptional programs, which could stimulate multiple injury-induced gene expression and contribute to axon regeneration and functional recovery. However, the role of HIF-1α in peripheral nerve regeneration remains to be fully elucidated. In this study, rats were divided into three groups and treated with sham surgery, surgery with cobalt chloride (CoCl2) and surgery with saline, respectively. Sciatic functional index, morphologic evaluations of muscle fibers, and never conduction velocity were performed to measure the functional recovery at 12 weeks postoperatively. In addition, the effects of CoCl2 on the expression of HIF-1α, glial cell line-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) were determined at mRNA levels; as well as HIF-1α, the dual leucine zipper kinase (DLK), the c-Jun N-terminal kinase (JNK), phosphorylated JNK (p-JNK), BDNF and NGF were measured at protein level at 4 weeks postoperatively. Systemic administration of CoCl2 (15 mg/kg/day intraperitoneally) significantly promoted functional recovery of rats with sciatic nerve transection injury. This study demonstrated in rats treated with CoCl2, the expression of HIF-1α, GDNF, BDNF and NGF was significantly increased at mRNA level, while HIF-1α, DLK, p-JNK, BDNF and NGF was significantly increased at protein level.
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Affiliation(s)
- Shuai An
- Department of Orthopedics, Xuanwu Hospital, Capital Medical University
| | - Meng Zhou
- Department of Orthopedics, Xuanwu Hospital, Capital Medical University
| | - Zheng Li
- Department of Orthopedics, Xuanwu Hospital, Capital Medical University
| | - Mingli Feng
- Department of Orthopedics, Xuanwu Hospital, Capital Medical University
| | - Guanglei Cao
- Department of Orthopedics, Xuanwu Hospital, Capital Medical University
| | - Shibao Lu
- Department of Orthopedics, Xuanwu Hospital, Capital Medical University
| | - Limin Liu
- Department of Orthopedics, Xuanwu Hospital, Capital Medical University
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112
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Ivakhnitskaia E, Lin RW, Hamada K, Chang C. Timing of neuronal plasticity in development and aging. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2017; 7. [PMID: 29139210 DOI: 10.1002/wdev.305] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 08/21/2017] [Accepted: 09/11/2017] [Indexed: 01/21/2023]
Abstract
Molecular oscillators are well known for their roles in temporal control of some biological processes like cell proliferation, but molecular mechanisms that provide temporal control of differentiation and postdifferentiation events in cells are less understood. In the nervous system, establishment of neuronal connectivity during development and decline in neuronal plasticity during aging are regulated with temporal precision, but the timing mechanisms are largely unknown. Caenorhabditis elegans has been a preferred model for aging research and recently emerges as a new model for the study of developmental and postdevelopmental plasticity in neurons. In this review we discuss the emerging mechanisms in timing of developmental lineage progression, axon growth and pathfinding, synapse formation, and reorganization, and neuronal plasticity in development and aging. We also provide a current view on the conserved core axon regeneration molecules with the intention to point out potential regulatory points of temporal controls. We highlight recent progress in understanding timing mechanisms that regulate decline in regenerative capacity, including progressive changes of intrinsic timers and co-opting the aging pathway molecules. WIREs Dev Biol 2018, 7:e305. doi: 10.1002/wdev.305 This article is categorized under: Invertebrate Organogenesis > Worms Establishment of Spatial and Temporal Patterns > Regulation of Size, Proportion, and Timing Nervous System Development > Worms Gene Expression and Transcriptional Hierarchies > Regulatory RNA.
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Affiliation(s)
- Evguenia Ivakhnitskaia
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA.,Medical Scientist Training Program, University of Illinois at Chicago, Chicago, IL, USA.,Graduate Program in Neuroscience, University of Illinois at Chicago, Chicago, IL, USA
| | - Ryan Weihsiang Lin
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Kana Hamada
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Chieh Chang
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA.,Graduate Program in Neuroscience, University of Illinois at Chicago, Chicago, IL, USA
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113
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Larhammar M, Huntwork-Rodriguez S, Rudhard Y, Sengupta-Ghosh A, Lewcock JW. The Ste20 Family Kinases MAP4K4, MINK1, and TNIK Converge to Regulate Stress-Induced JNK Signaling in Neurons. J Neurosci 2017; 37:11074-11084. [PMID: 28993483 PMCID: PMC6596808 DOI: 10.1523/jneurosci.0905-17.2017] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 09/13/2017] [Accepted: 10/02/2017] [Indexed: 11/21/2022] Open
Abstract
The c-Jun-N-terminal kinase (JNK) signaling pathway regulates nervous system development, axon regeneration, and neuronal degeneration after acute injury or in chronic neurodegenerative disease. Dual leucine zipper kinase (DLK) is required for stress-induced JNK signaling in neurons, yet the factors that initiate DLK/JNK pathway activity remain poorly defined. In the present study, we identify the Ste20 kinases MAP4K4, misshapen-like kinase 1 (MINK1 or MAP4K6) and TNIK Traf2- and Nck-interacting kinase (TNIK or MAP4K7), as upstream regulators of DLK/JNK signaling in neurons. Using a trophic factor withdrawal-based model of neurodegeneration in both male and female embryonic mouse dorsal root ganglion neurons, we show that MAP4K4, MINK1, and TNIK act redundantly to regulate DLK activation and downstream JNK-dependent phosphorylation of c-Jun in response to stress. Targeting MAP4K4, MINK1, and TNIK, but not any of these kinases individually, is sufficient to protect neurons potently from degeneration. Pharmacological inhibition of MAP4Ks blocks stabilization and phosphorylation of DLK within axons and subsequent retrograde translocation of the JNK signaling complex to the nucleus. These results position MAP4Ks as important regulators of the DLK/JNK signaling pathway.SIGNIFICANCE STATEMENT Neuronal degeneration occurs in disparate circumstances: during development to refine neuronal connections, after injury to clear damaged neurons, or pathologically during disease. The dual leucine zipper kinase (DLK)/c-Jun-N-terminal kinase (JNK) pathway represents a conserved regulator of neuronal injury signaling that drives both neurodegeneration and axon regeneration, yet little is known about the factors that initiate DLK activity. Here, we uncover a novel role for a subfamily of MAP4 kinases consisting of MAP4K4, Traf2- and Nck-interacting kinase (TNIK or MAP4K7), and misshapen-like kinase 1 (MINK1 or MAP4K6) in regulating DLK/JNK signaling in neurons. Inhibition of these MAP4Ks blocks stress-induced retrograde JNK signaling and protects from neurodegeneration, suggesting that these kinases may represent attractive therapeutic targets.
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Affiliation(s)
- Martin Larhammar
- Department of Neuroscience, Genentech, Inc., San Francisco, California 94080
- Denali Therapeutics Inc., South San Francisco, California 94080
| | - Sarah Huntwork-Rodriguez
- Department of Neuroscience, Genentech, Inc., San Francisco, California 94080
- Denali Therapeutics Inc., South San Francisco, California 94080
| | - York Rudhard
- In Vitro Pharmacology, Evotec AG, Manfred Eigen Campus, 22419 Hamburg, Germany, and
| | | | - Joseph W Lewcock
- Department of Neuroscience, Genentech, Inc., San Francisco, California 94080,
- Denali Therapeutics Inc., South San Francisco, California 94080
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114
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Phosphatidylserine save-me signals drive functional recovery of severed axons in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2017; 114:E10196-E10205. [PMID: 29109263 PMCID: PMC5703272 DOI: 10.1073/pnas.1703807114] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Nervous system injury can cause lifelong disability, because repair rarely leads to reconnection with the target tissue. In the nematode Caenorhabditis elegans and in several other species, regeneration can proceed through a mechanism of axonal fusion, whereby regrowing axons reconnect and fuse with their own separated fragments, rapidly and efficiently restoring the original axonal tract. We have found that the process of axonal fusion restores full function to damaged neurons. In addition, we show that injury-induced changes to the axonal membrane that result in exposure of lipid “save-me” signals mediate the level of axonal fusion. Thus, our results establish axonal fusion as a complete regenerative mechanism that can be modulated by changing the level of save-me signals exposed after injury. Functional regeneration after axonal injury requires transected axons to regrow and reestablish connection with their original target tissue. The spontaneous regenerative mechanism known as axonal fusion provides a highly efficient means of achieving targeted reconnection, as a regrowing axon is able to recognize and fuse with its own detached axon segment, thereby rapidly reestablishing the original axonal tract. Here, we use behavioral assays and fluorescent reporters to show that axonal fusion enables full recovery of function after axotomy of Caenorhabditis elegans mechanosensory neurons. Furthermore, we reveal that the phospholipid phosphatidylserine, which becomes exposed on the damaged axon to function as a “save-me” signal, defines the level of axonal fusion. We also show that successful axonal fusion correlates with the regrowth potential and branching of the proximal fragment and with the retraction length and degeneration of the separated segment. Finally, we identify discrete axonal domains that vary in their propensity to regrow through fusion and show that the level of axonal fusion can be genetically modulated. Taken together, our results reveal that axonal fusion restores full function to injured neurons, is dependent on exposure of phospholipid signals, and is achieved through the balance between regenerative potential and level of degeneration.
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115
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Borgen MA, Wang D, Grill B. RPM-1 regulates axon termination by affecting growth cone collapse and microtubule stability. Development 2017; 144:4658-4672. [PMID: 29084805 DOI: 10.1242/dev.154187] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 10/21/2017] [Indexed: 12/14/2022]
Abstract
Axon termination is essential for efficient and accurate nervous system construction. At present, relatively little is known about how growth cone collapse occurs prior to axon termination in vivo Using the mechanosensory neurons of C. elegans, we found collapse prior to axon termination is protracted, with the growth cone transitioning from a dynamic to a static state. Growth cone collapse prior to termination is facilitated by the signaling hub RPM-1. Given the prominence of the cytoskeleton in growth cone collapse, we assessed the relationship between RPM-1 and regulators of actin dynamics and microtubule stability. Our results reveal several important findings about how axon termination is orchestrated: (1) RPM-1 functions in parallel to RHO-1 and CRMP/UNC-33, but is suppressed by the Rac isoform MIG-2; (2) RPM-1 opposes the function of microtubule stabilizers, including tubulin acetyltransferases; and (3) genetic epistasis suggests the microtubule-stabilizing protein Tau/PTL-1 potentially inhibits RPM-1. These findings provide insight into how growth cone collapse is regulated during axon termination in vivo, and suggest that RPM-1 signaling destabilizes microtubules to facilitate growth cone collapse and axon termination.
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Affiliation(s)
- Melissa A Borgen
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL 33458, USA
| | - Dandan Wang
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL 33458, USA
| | - Brock Grill
- Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, FL 33458, USA
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116
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Yu B, Wang X, Wei S, Fu T, Dzakah EE, Waqas A, Walthall WW, Shan G. Convergent Transcriptional Programs Regulate cAMP Levels in C. elegans GABAergic Motor Neurons. Dev Cell 2017; 43:212-226.e7. [PMID: 29033363 DOI: 10.1016/j.devcel.2017.09.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 06/26/2017] [Accepted: 09/15/2017] [Indexed: 02/07/2023]
Abstract
Both transcriptional regulation and signaling pathways play crucial roles in neuronal differentiation and plasticity. Caenorhabditis elegans possesses 19 GABAergic motor neurons (MNs) called D MNs, which are divided into two subgroups: DD and VD. DD, but not VD, MNs reverse their cellular polarity in a developmental process called respecification. UNC-30 and UNC-55 are two critical transcription factors in D MNs. By using chromatin immunoprecipitation with CRISPR/Cas9 knockin of GFP fusion, we uncovered the global targets of UNC-30 and UNC-55. UNC-30 and UNC-55 are largely converged to regulate over 1,300 noncoding and coding genes, and genes in multiple biological processes, including cAMP metabolism, are co-regulated. Increase in cAMP levels may serve as a timing signal for respecification, whereas UNC-55 regulates genes such as pde-4 to keep the cAMP levels low in VD. Other genes modulating DD respecification such as lin-14, irx-1, and oig-1 are also found to affect cAMP levels.
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Affiliation(s)
- Bin Yu
- CAS Key Laboratory of Innate Immunity and Chronic Disease, CAS Center for Excellence in Molecular Cell Science, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui Province 230027, China
| | - Xiaolin Wang
- CAS Key Laboratory of Innate Immunity and Chronic Disease, CAS Center for Excellence in Molecular Cell Science, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui Province 230027, China
| | - Shuai Wei
- CAS Key Laboratory of Innate Immunity and Chronic Disease, CAS Center for Excellence in Molecular Cell Science, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui Province 230027, China
| | - Tao Fu
- CAS Key Laboratory of Innate Immunity and Chronic Disease, CAS Center for Excellence in Molecular Cell Science, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui Province 230027, China
| | - Emmanuel Enoch Dzakah
- CAS Key Laboratory of Innate Immunity and Chronic Disease, CAS Center for Excellence in Molecular Cell Science, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui Province 230027, China
| | - Ahmed Waqas
- CAS Key Laboratory of Innate Immunity and Chronic Disease, CAS Center for Excellence in Molecular Cell Science, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui Province 230027, China
| | - Walter W Walthall
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA
| | - Ge Shan
- CAS Key Laboratory of Innate Immunity and Chronic Disease, CAS Center for Excellence in Molecular Cell Science, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui Province 230027, China.
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117
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Li J, Zhang YV, Asghari Adib E, Stanchev DT, Xiong X, Klinedinst S, Soppina P, Jahn TR, Hume RI, Rasse TM, Collins CA. Restraint of presynaptic protein levels by Wnd/DLK signaling mediates synaptic defects associated with the kinesin-3 motor Unc-104. eLife 2017; 6:e24271. [PMID: 28925357 PMCID: PMC5605197 DOI: 10.7554/elife.24271] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 08/11/2017] [Indexed: 12/19/2022] Open
Abstract
The kinesin-3 family member Unc-104/KIF1A is required for axonal transport of many presynaptic components to synapses, and mutation of this gene results in synaptic dysfunction in mice, flies and worms. Our studies at the Drosophila neuromuscular junction indicate that many synaptic defects in unc-104-null mutants are mediated independently of Unc-104's transport function, via the Wallenda (Wnd)/DLK MAP kinase axonal damage signaling pathway. Wnd signaling becomes activated when Unc-104's function is disrupted, and leads to impairment of synaptic structure and function by restraining the expression level of active zone (AZ) and synaptic vesicle (SV) components. This action concomitantly suppresses the buildup of synaptic proteins in neuronal cell bodies, hence may play an adaptive role to stresses that impair axonal transport. Wnd signaling also becomes activated when pre-synaptic proteins are over-expressed, suggesting the existence of a feedback circuit to match synaptic protein levels to the transport capacity of the axon.
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Affiliation(s)
- Jiaxing Li
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborUnited States
| | - Yao V Zhang
- Junior Research Group Synaptic PlasticityHertie-Institute for Clinical Brain Research, University of TübingenTübingenGermany
- Graduate School of Cellular and Molecular NeuroscienceUniversity of TübingenTübingenGermany
| | - Elham Asghari Adib
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborUnited States
| | - Doychin T Stanchev
- Junior Research Group Synaptic PlasticityHertie-Institute for Clinical Brain Research, University of TübingenTübingenGermany
- Graduate School of Cellular and Molecular NeuroscienceUniversity of TübingenTübingenGermany
| | - Xin Xiong
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborUnited States
| | - Susan Klinedinst
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborUnited States
| | - Pushpanjali Soppina
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborUnited States
| | - Thomas Robert Jahn
- CHS Research Group Proteostasis in Neurodegenerative DiseaseDKFZ Deutsches KrebsforschungszentrumHeidelbergGermany
| | - Richard I Hume
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborUnited States
| | - Tobias M Rasse
- Junior Research Group Synaptic PlasticityHertie-Institute for Clinical Brain Research, University of TübingenTübingenGermany
- CHS Research Group Proteostasis in Neurodegenerative DiseaseDKFZ Deutsches KrebsforschungszentrumHeidelbergGermany
| | - Catherine A Collins
- Department of Molecular, Cellular, and Developmental BiologyUniversity of MichiganAnn ArborUnited States
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118
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Gokce SK, Hegarty EM, Mondal S, Zhao P, Ghorashian N, Hilliard MA, Ben-Yakar A. A multi-trap microfluidic chip enabling longitudinal studies of nerve regeneration in Caenorhabditis elegans. Sci Rep 2017; 7:9837. [PMID: 28852096 PMCID: PMC5575036 DOI: 10.1038/s41598-017-10302-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 08/07/2017] [Indexed: 11/10/2022] Open
Abstract
Several sophisticated microfluidic devices have recently been proposed for femtosecond laser axotomy in the nematode C. elegans for immobilization of the animals for surgery to overcome time-consuming and labor-intensive manual processes. However, nerve regeneration studies require long-term recovery of the animals and multiple imaging sessions to observe the regeneration capabilities of their axons post-injury. Here we present a simple, multi-trap device, consisting of a single PDMS (polydimethylsiloxane) layer, which can immobilize up to 20 animals at the favorable orientation for optical access needed for precise laser surgery and high-resolution imaging. The new device, named “worm hospital” allows us to perform the entire nerve regeneration studies, including on-chip axotomy, post-surgery housing for recovery, and post-recovery imaging all on one microfluidic chip. Utilizing the worm hospital and analysis of mutants, we observed that most but not all neurodevelopmental genes in the Wnt/Frizzled pathway are important for regeneration of the two touch receptor neurons ALM and PLM. Using our new chip, we observed that the cwn-2 and cfz-2 mutations significantly reduced the reconnection possibilities of both neurons without any significant reduction in the regrowth lengths of the severed axons. We observed a similar regeneration phenotype with cwn-1 mutation in ALM neurons only.
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Affiliation(s)
- Sertan Kutal Gokce
- Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Evan Marley Hegarty
- Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Sudip Mondal
- Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Peisen Zhao
- Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Navid Ghorashian
- Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Massimo A Hilliard
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Adela Ben-Yakar
- Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, 78712, USA. .,Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA. .,Biomedical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA. .,Institute for Neuroscience, The University of Texas at Austin, Austin, TX, 78712, USA.
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119
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The Core Molecular Machinery Used for Engulfment of Apoptotic Cells Regulates the JNK Pathway Mediating Axon Regeneration in Caenorhabditis elegans. J Neurosci 2017; 36:9710-21. [PMID: 27629720 DOI: 10.1523/jneurosci.0453-16.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 07/25/2016] [Indexed: 02/04/2023] Open
Abstract
UNLABELLED The mechanisms that govern the ability of specific neurons to regenerate their axons after injury are not well understood. In Caenorhabditis elegans, the initiation of axon regeneration is positively regulated by the JNK-MAPK pathway. In this study, we identify two components functioning upstream of the JNK pathway: the Ste20-related protein kinase MAX-2 and the Rac-type GTPase CED-10. CED-10, when bound by GTP, interacts with MAX-2 and functions as its upstream regulator in axon regeneration. CED-10, in turn, is activated by axon injury via signals initiated from the integrin α-subunit INA-1 and the nonreceptor tyrosine kinase SRC-1 and transmitted via the signaling module CED-2/CrkII-CED-5/Dock180-CED-12/ELMO. This module is also known to regulate the engulfment of apoptotic cells during development. Our findings thus reveal that the molecular machinery used for engulfment of apoptotic cells also promotes axon regeneration through activation of the JNK pathway. SIGNIFICANCE STATEMENT The molecular mechanisms of axon regeneration after injury remain poorly understood. In Caenorhabditis elegans, the initiation of axon regeneration is positively regulated by the JNK-MAPK pathway. In this study, we show that integrin, Rac-GTPase, and several other molecules, all of which are known to regulate engulfment of apoptotic cells during development, also regulate axon regeneration. This signaling module activates the JNK-MAPK cascade via MAX-2, a PAK-like protein kinase that binds Rac. Our findings thus reveal that the molecular machinery used for engulfment of apoptotic cells also promotes axon regeneration through activation of the JNK pathway.
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120
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Rao KS, Rolls MM. Two Drosophila model neurons can regenerate axons from the stump or from a converted dendrite, with feedback between the two sites. Neural Dev 2017; 12:15. [PMID: 28818097 PMCID: PMC5561650 DOI: 10.1186/s13064-017-0092-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 08/09/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND After axon severing, neurons recover function by reinitiating axon outgrowth. New outgrowth often originates from the remaining axon stump. However, in many mammalian neurons, new axons initiate from a dendritic site when the axon is injured close to the cell body. METHODS Drosophila sensory neurons are ideal for studying neuronal injury responses because they can be injured reproducibly in a variety of genetic backgrounds. In Drosophila, it has been shown that a complex sensory neuron, ddaC, can regenerate an axon from a stump, and a simple sensory neuron, ddaE, can regenerate an axon from a dendrite. To provide a more complete picture of axon regeneration in these cell types, we performed additional injury types. RESULTS We found that ddaE neurons can initiate regeneration from an axon stump when a stump remains. We also showed that ddaC neurons regenerate from the dendrite when the axon is severed close to the cell body. We next demonstrated if a stump remains, new axons can originate from this site and a dendrite at the same time. Because cutting the axon close to the cell body results in growth of the new axon from a dendrite, and cutting further out may not, we asked whether the initial response in the cell body was similar after both types of injury. A transcriptional reporter for axon injury signaling, puc-GFP, increased with similar timing and levels after proximal and distal axotomy. However, changes in dendritic microtubule polarity differed in response to the two types of injury, and were influenced by the presence of a scar at the distal axotomy site. CONCLUSIONS We conclude that both ddaE and ddaC can regenerate axons either from the stump or a dendrite, and that there is some feedback between the two sites that modulates dendritic microtubule polarity.
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Affiliation(s)
- Kavitha S Rao
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Melissa M Rolls
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA.
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121
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Noma K, Goncharov A, Ellisman MH, Jin Y. Microtubule-dependent ribosome localization in C. elegans neurons. eLife 2017; 6:26376. [PMID: 28767038 PMCID: PMC5577916 DOI: 10.7554/elife.26376] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 08/01/2017] [Indexed: 01/23/2023] Open
Abstract
Subcellular localization of ribosomes defines the location and capacity for protein synthesis. Methods for in vivo visualizing ribosomes in multicellular organisms are desirable in mechanistic investigations of the cell biology of ribosome dynamics. Here, we developed an approach using split GFP for tissue-specific visualization of ribosomes in Caenorhabditis elegans. Labeled ribosomes are detected as fluorescent puncta in the axons and synaptic terminals of specific neuron types, correlating with ribosome distribution at the ultrastructural level. We found that axonal ribosomes change localization during neuronal development and after axonal injury. By examining mutants affecting axonal trafficking and performing a forward genetic screen, we showed that the microtubule cytoskeleton and the JIP3 protein UNC-16 exert distinct effects on localization of axonal and somatic ribosomes. Our data demonstrate the utility of tissue-specific visualization of ribosomes in vivo, and provide insight into the mechanisms of active regulation of ribosome localization in neurons.
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Affiliation(s)
- Kentaro Noma
- Division of Biological Sciences, Neurobiology Section, University of California, San Diego, San Diego, United States.,Howard Hughes Medical Institute, University of California, San Diego, San Diego, United States
| | - Alexandr Goncharov
- Division of Biological Sciences, Neurobiology Section, University of California, San Diego, San Diego, United States.,Howard Hughes Medical Institute, University of California, San Diego, San Diego, United States
| | - Mark H Ellisman
- National Center for Research in Biological Systems, Department of Neurosciences, School of Medicine, University of California, San Diego, San Diego, United States
| | - Yishi Jin
- Division of Biological Sciences, Neurobiology Section, University of California, San Diego, San Diego, United States.,Howard Hughes Medical Institute, University of California, San Diego, San Diego, United States
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122
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Han SM, Baig HS, Hammarlund M. Mitochondria Localize to Injured Axons to Support Regeneration. Neuron 2017; 92:1308-1323. [PMID: 28009276 DOI: 10.1016/j.neuron.2016.11.025] [Citation(s) in RCA: 158] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 08/31/2016] [Accepted: 11/08/2016] [Indexed: 12/19/2022]
Abstract
Axon regeneration is essential to restore the nervous system after axon injury. However, the neuronal cell biology that underlies axon regeneration is incompletely understood. Here we use in vivo, single-neuron analysis to investigate the relationship between nerve injury, mitochondrial localization, and axon regeneration. Mitochondria translocate into injured axons so that average mitochondria density increases after injury. Moreover, single-neuron analysis reveals that axons that fail to increase mitochondria have poor regeneration. Experimental alterations to axonal mitochondrial distribution or mitochondrial respiratory chain function result in corresponding changes to regeneration outcomes. Axonal mitochondria are specifically required for growth-cone migration, identifying a key energy challenge for injured neurons. Finally, mitochondrial localization to the axon after injury is regulated in part by dual-leucine zipper kinase 1 (DLK-1), a conserved regulator of axon regeneration. These data identify regulation of axonal mitochondria as a new cell-biological mechanism that helps determine the regenerative response of injured neurons.
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Affiliation(s)
- Sung Min Han
- Departments of Genetics and Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Huma S Baig
- Departments of Genetics and Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Marc Hammarlund
- Departments of Genetics and Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA.
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123
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Optogenetic Interrogation of Functional Synapse Formation by Corticospinal Tract Axons in the Injured Spinal Cord. J Neurosci 2017; 36:5877-90. [PMID: 27225775 DOI: 10.1523/jneurosci.4203-15.2016] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 04/08/2016] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED To restore function after injury to the CNS, axons must be stimulated to extend into denervated territory and, critically, must form functional synapses with appropriate targets. We showed previously that forced overexpression of the transcription factor Sox11 increases axon growth by corticospinal tract (CST) neurons after spinal injury. However, behavioral outcomes were not improved, raising the question of whether the newly sprouted axons are able to form functional synapses. Here we developed an optogenetic strategy, paired with single-unit extracellular recordings, to assess the ability of Sox11-stimulated CST axons to functionally integrate in the circuitry of the cervical spinal cord. Initial time course experiments established the expression and function of virally expressed Channelrhodopsin (ChR2) in CST cell bodies and in axon terminals in cervical spinal cord. Pyramidotomies were performed in adult mice to deprive the left side of the spinal cord of CST input, and the right CST was treated with adeno-associated virus (AAV)-Sox11 or AAV-EBFP control, along with AAV-ChR2. As expected, Sox11 treatment caused robust midline crossing of CST axons into previously denervated left spinal cord. Clear postsynaptic responses resulted from optogenetic activation of CST terminals, demonstrating the ability of Sox11-stimulated axons to form functional synapses. Mapping of the distribution of CST-evoked spinal activity revealed overall similarity between intact and newly innervated spinal tissue. These data demonstrate the formation of functional synapses by Sox11-stimulated CST axons without significant behavioral benefit, suggesting that new synapses may be mistargeted or otherwise impaired in the ability to coordinate functional output. SIGNIFICANCE STATEMENT As continued progress is made in promoting the regeneration of CNS axons, questions of synaptic integration are increasingly prominent. Demonstrating direct synaptic integration by regenerated axons and distinguishing its function from indirect relay circuits and target field plasticity have presented technical challenges. Here we force the overexpression of Sox11 to stimulate the growth of corticospinal tract axons in the cervical spinal cord and then use specific optogenetic activation to assess their ability to directly drive postsynaptic activity in spinal cord neurons. By confirming successful synaptic integration, these data illustrate a novel optogenetic-based strategy to monitor and optimize functional reconnection by newly sprouted axons in the injured CNS.
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124
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Distinct cis elements in the 3' UTR of the C. elegans cebp-1 mRNA mediate its regulation in neuronal development. Dev Biol 2017; 429:240-248. [PMID: 28673818 DOI: 10.1016/j.ydbio.2017.06.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 06/19/2017] [Accepted: 06/19/2017] [Indexed: 12/13/2022]
Abstract
The 3' untranslated regions (3' UTRs) of mRNAs mediate post-transcriptional regulation of genes in many biological processes. Cis elements in 3' UTRs can interact with RNA-binding factors in sequence-specific or structure-dependent manners, enabling regulation of mRNA stability, translation, and localization. Caenorhabditis elegans CEBP-1 is a conserved transcription factor of the C/EBP family, and functions in diverse contexts, from neuronal development and axon regeneration to organismal growth. Previous studies revealed that the levels of cebp-1 mRNA in neurons depend on its 3' UTR and are also negatively regulated by the E3 ubiquitin ligase RPM-1. Here, by systematically dissecting cebp-1's 3' UTR, we test the roles of specific cis elements in cebp-1 expression and function in neurons. We present evidence for a putative stem-loop in the cebp-1 3' UTR that contributes to basal expression levels of mRNA and to negative regulation by rpm-1. Mutant animals lacking the endogenous cebp-1 3' UTR showed a noticeable increased expression of cebp-1 mRNA and enhanced the neuronal developmental phenotypes of rpm-1 mutants. Our data reveal multiple cis elements within cebp-1's 3' UTR that help to optimize CEBP-1 expression levels in neuronal development.
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125
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Wang S, Tang NH, Lara-Gonzalez P, Zhao Z, Cheerambathur DK, Prevo B, Chisholm AD, Desai A, Oegema K. A toolkit for GFP-mediated tissue-specific protein degradation in C. elegans. Development 2017; 144:2694-2701. [PMID: 28619826 DOI: 10.1242/dev.150094] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 06/08/2017] [Indexed: 02/05/2023]
Abstract
Proteins that are essential for embryo production, cell division and early embryonic events are frequently reused later in embryogenesis, during organismal development or in the adult. Examining protein function across these different biological contexts requires tissue-specific perturbation. Here, we describe a method that uses expression of a fusion between a GFP-targeting nanobody and a SOCS-box containing ubiquitin ligase adaptor to target GFP-tagged proteins for degradation. When combined with endogenous locus GFP tagging by CRISPR-Cas9 or with rescue of a null mutant with a GFP fusion, this approach enables routine and efficient tissue-specific protein ablation. We show that this approach works in multiple tissues - the epidermis, intestine, body wall muscle, ciliated sensory neurons and touch receptor neurons - where it recapitulates expected loss-of-function mutant phenotypes. The transgene toolkit and the strain set described here will complement existing approaches to enable routine analysis of the tissue-specific roles of C. elegans proteins.
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Affiliation(s)
- Shaohe Wang
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Ngang Heok Tang
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Pablo Lara-Gonzalez
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Zhiling Zhao
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Dhanya K Cheerambathur
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Bram Prevo
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Andrew D Chisholm
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Arshad Desai
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Karen Oegema
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
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126
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Upadhyay A, Joshi V, Amanullah A, Mishra R, Arora N, Prasad A, Mishra A. E3 Ubiquitin Ligases Neurobiological Mechanisms: Development to Degeneration. Front Mol Neurosci 2017; 10:151. [PMID: 28579943 PMCID: PMC5437216 DOI: 10.3389/fnmol.2017.00151] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 05/04/2017] [Indexed: 01/08/2023] Open
Abstract
Cells regularly synthesize new proteins to replace old or damaged proteins. Deposition of various aberrant proteins in specific brain regions leads to neurodegeneration and aging. The cellular protein quality control system develop various defense mechanisms against the accumulation of misfolded and aggregated proteins. The mechanisms underlying the selective recognition of specific crucial protein or misfolded proteins are majorly governed by quality control E3 ubiquitin ligases mediated through ubiquitin-proteasome system. Few known E3 ubiquitin ligases have shown prominent neurodevelopmental functions, but their interactions with different developmental proteins play critical roles in neurodevelopmental disorders. Several questions are yet to be understood properly. How E3 ubiquitin ligases determine the specificity and regulate degradation of a particular substrate involved in neuronal proliferation and differentiation is certainly the one, which needs detailed investigations. Another important question is how neurodevelopmental E3 ubiquitin ligases specifically differentiate between their versatile range of substrates and timing of their functional modulations during different phases of development. The premise of this article is to understand how few E3 ubiquitin ligases sense major molecular events, which are crucial for human brain development from its early embryonic stages to throughout adolescence period. A better understanding of these few E3 ubiquitin ligases and their interactions with other potential proteins will provide invaluable insight into disease mechanisms to approach toward therapeutic interventions.
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Affiliation(s)
- Arun Upadhyay
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology JodhpurJodhpur, India
| | - Vibhuti Joshi
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology JodhpurJodhpur, India
| | - Ayeman Amanullah
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology JodhpurJodhpur, India
| | - Ribhav Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology JodhpurJodhpur, India
| | - Naina Arora
- School of Basic Sciences, Indian Institute of Technology MandiMandi, India
| | - Amit Prasad
- School of Basic Sciences, Indian Institute of Technology MandiMandi, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology JodhpurJodhpur, India
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127
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Knowlton WM, Hubert T, Wu Z, Chisholm AD, Jin Y. A Select Subset of Electron Transport Chain Genes Associated with Optic Atrophy Link Mitochondria to Axon Regeneration in Caenorhabditis elegans. Front Neurosci 2017; 11:263. [PMID: 28539870 PMCID: PMC5423972 DOI: 10.3389/fnins.2017.00263] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/24/2017] [Indexed: 12/13/2022] Open
Abstract
The role of mitochondria within injured neurons is an area of active interest since these organelles are vital for the production of cellular energy in the form of ATP. Using mechanosensory neurons of the nematode Caenorhabditis elegans to test regeneration after neuronal injury in vivo, we surveyed genes related to mitochondrial function for effects on axon regrowth after laser axotomy. Genes involved in mitochondrial transport, calcium uptake, mitophagy, or fission and fusion were largely dispensable for axon regrowth, with the exception of eat-3/Opa1. Surprisingly, many genes encoding components of the electron transport chain were dispensable for regrowth, except for the iron-sulfur proteins gas-1, nduf-2.2, nduf-7, and isp-1, and the putative oxidoreductase rad-8. In these mutants, axonal development was essentially normal and axons responded normally to injury by forming regenerative growth cones, but were impaired in subsequent axon extension. Overexpression of nduf-2.2 or isp-1 was sufficient to enhance regrowth, suggesting that mitochondrial function is rate-limiting in axon regeneration. Moreover, loss of function in isp-1 reduced the enhanced regeneration caused by either a gain-of-function mutation in the calcium channel EGL-19 or overexpression of the MAP kinase DLK-1. While the cellular function of RAD-8 remains unclear, our genetic analyses place rad-8 in the same pathway as other electron transport genes in axon regeneration. Unexpectedly, rad-8 regrowth defects were suppressed by altered function in the ubiquinone biosynthesis gene clk-1. Furthermore, we found that inhibition of the mitochondrial unfolded protein response via deletion of atfs-1 suppressed the defective regrowth in nduf-2.2 mutants. Together, our data indicate that while axon regeneration is not significantly affected by general dysfunction of cellular respiration, it is sensitive to the proper functioning of a select subset of electron transport chain genes, or to the cellular adaptations used by neurons under conditions of injury.
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Affiliation(s)
- Wendy M Knowlton
- Section of Neurobiology, Division of Biological Sciences, University of CaliforniaSan Diego, CA, USA
| | - Thomas Hubert
- Section of Neurobiology, Division of Biological Sciences, University of CaliforniaSan Diego, CA, USA
| | - Zilu Wu
- Howard Hughes Medical Institute, University of CaliforniaSan Diego, CA, USA
| | - Andrew D Chisholm
- Section of Neurobiology, Division of Biological Sciences, University of CaliforniaSan Diego, CA, USA
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, University of CaliforniaSan Diego, CA, USA.,Howard Hughes Medical Institute, University of CaliforniaSan Diego, CA, USA.,Department of Cellular and Molecular Medicine, School of Medicine, University of CaliforniaSan Diego, CA, USA
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128
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Oren-Suissa M, Gattegno T, Kravtsov V, Podbilewicz B. Extrinsic Repair of Injured Dendrites as a Paradigm for Regeneration by Fusion in Caenorhabditis elegans. Genetics 2017; 206:215-230. [PMID: 28283540 PMCID: PMC5419471 DOI: 10.1534/genetics.116.196386] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 03/07/2017] [Indexed: 11/18/2022] Open
Abstract
Injury triggers regeneration of axons and dendrites. Research has identified factors required for axonal regeneration outside the CNS, but little is known about regeneration triggered by dendrotomy. Here, we study neuronal plasticity triggered by dendrotomy and determine the fate of complex PVD arbors following laser surgery of dendrites. We find that severed primary dendrites grow toward each other and reconnect via branch fusion. Simultaneously, terminal branches lose self-avoidance and grow toward each other, meeting and fusing at the tips via an AFF-1-mediated process. Ectopic branch growth is identified as a step in the regeneration process required for bypassing the lesion site. Failure of reconnection to the severed dendrites results in degeneration of the distal end of the neuron. We discover pruning of excess branches via EFF-1 that acts to recover the original wild-type arborization pattern in a late stage of the process. In contrast, AFF-1 activity during dendritic auto-fusion is derived from the lateral seam cells and not autonomously from the PVD neuron. We propose a model in which AFF-1-vesicles derived from the epidermal seam cells fuse neuronal dendrites. Thus, EFF-1 and AFF-1 fusion proteins emerge as new players in neuronal arborization and maintenance of arbor connectivity following injury in Caenorhabditis elegans Our results demonstrate that there is a genetically determined multi-step pathway to repair broken dendrites in which EFF-1 and AFF-1 act on different steps of the pathway. EFF-1 is essential for dendritic pruning after injury and extrinsic AFF-1 mediates dendrite fusion to bypass injuries.
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Affiliation(s)
- Meital Oren-Suissa
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Tamar Gattegno
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Veronika Kravtsov
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Benjamin Podbilewicz
- Department of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
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129
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Rangaraju V, Tom Dieck S, Schuman EM. Local translation in neuronal compartments: how local is local? EMBO Rep 2017; 18:693-711. [PMID: 28404606 DOI: 10.15252/embr.201744045] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/15/2017] [Accepted: 03/15/2017] [Indexed: 12/18/2022] Open
Abstract
Efficient neuronal function depends on the continued modulation of the local neuronal proteome. Local protein synthesis plays a central role in tuning the neuronal proteome at specific neuronal regions. Various aspects of translation such as the localization of translational machinery, spatial spread of the newly translated proteins, and their site of action are carried out in specialized neuronal subcompartments to result in a localized functional outcome. In this review, we focus on the various aspects of these local translation compartments such as size, biochemical and organelle composition, structural boundaries, and temporal dynamics. We also discuss the apparent absence of definitive components of translation in these local compartments and the emerging state-of-the-art tools that could help dissecting these conundrums in greater detail in the future.
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Affiliation(s)
- Vidhya Rangaraju
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| | | | - Erin M Schuman
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
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130
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Germ Granules Prevent Accumulation of Somatic Transcripts in the Adult Caenorhabditis elegans Germline. Genetics 2017; 206:163-178. [PMID: 28258184 DOI: 10.1534/genetics.116.198549] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 03/01/2017] [Indexed: 11/18/2022] Open
Abstract
The germ cells of multicellular organisms protect their developmental potential through specialized mechanisms. A shared feature of germ cells from worms to humans is the presence of nonmembrane-bound, ribonucleoprotein organelles called germ granules. Depletion of germ granules in Caenorhabditis elegans (i.e., P granules) leads to sterility and, in some germlines, expression of the neuronal transgene unc-119::gfp and the muscle myosin MYO-3 Thus, P granules are hypothesized to maintain germ cell totipotency by preventing somatic development, although the mechanism by which P granules carry out this function is unknown. In this study, we performed transcriptome and single molecule RNA-FISH analyses of dissected P granule-depleted gonads at different developmental stages. Our results demonstrate that P granules are necessary for adult germ cells to downregulate spermatogenesis RNAs and to prevent the accumulation of numerous soma-specific RNAs. P granule-depleted gonads that express the unc-119::gfp transgene also express many other genes involved in neuronal development and concomitantly lose expression of germ cell fate markers. Finally, we show that removal of either of two critical P-granule components, PGL-1 or GLH-1, is sufficient to cause germ cells to express UNC-119::GFP and MYO-3 and to display RNA accumulation defects similar to those observed after depletion of P granules. Our data identify P granules as critical modulators of the germline transcriptome and guardians of germ cell fate.
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131
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Hisamoto N, Matsumoto K. Signal transduction cascades in axon regeneration: insights from C. elegans. Curr Opin Genet Dev 2017; 44:54-60. [PMID: 28213159 DOI: 10.1016/j.gde.2017.01.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 01/13/2017] [Accepted: 01/26/2017] [Indexed: 02/07/2023]
Abstract
Axon regeneration after nerve injury is a conserved biological process in many animals, including humans. The nematode Caenorhabditis elegans (C. elegans) has recently emerged as a genetically tractable model for studying regenerative responses in neurons. Extensive studies over several years using this organism have revealed a number of intrinsic and extrinsic signal transduction cascades that regulate axon regeneration, and these are found to be conserved from worms to humans. Further studies have demonstrated that these cascades consist of several signaling networks that ultimately merge into the c-Jun N-terminal kinase (JNK) cascade. In this review, we describe some recent insights into the signaling cascades controlling axon regeneration in C. elegans and describe their conserved roles in other organisms including mammals.
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Affiliation(s)
- Naoki Hisamoto
- Department of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.
| | - Kunihiro Matsumoto
- Department of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.
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132
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Activity-dependent synapse to nucleus signaling. Neurobiol Learn Mem 2017; 138:78-84. [DOI: 10.1016/j.nlm.2016.07.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Revised: 07/20/2016] [Accepted: 07/23/2016] [Indexed: 11/15/2022]
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133
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Huang YWA, Zhou B, Wernig M, Südhof TC. ApoE2, ApoE3, and ApoE4 Differentially Stimulate APP Transcription and Aβ Secretion. Cell 2017; 168:427-441.e21. [PMID: 28111074 DOI: 10.1016/j.cell.2016.12.044] [Citation(s) in RCA: 345] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 09/27/2016] [Accepted: 12/22/2016] [Indexed: 12/14/2022]
Abstract
Human apolipoprotein E (ApoE) apolipoprotein is primarily expressed in three isoforms (ApoE2, ApoE3, and ApoE4) that differ only by two residues. ApoE4 constitutes the most important genetic risk factor for Alzheimer's disease (AD), ApoE3 is neutral, and ApoE2 is protective. How ApoE isoforms influence AD pathogenesis, however, remains unclear. Using ES-cell-derived human neurons, we show that ApoE secreted by glia stimulates neuronal Aβ production with an ApoE4 > ApoE3 > ApoE2 potency rank order. We demonstrate that ApoE binding to ApoE receptors activates dual leucine-zipper kinase (DLK), a MAP-kinase kinase kinase that then activates MKK7 and ERK1/2 MAP kinases. Activated ERK1/2 induces cFos phosphorylation, stimulating the transcription factor AP-1, which in turn enhances transcription of amyloid-β precursor protein (APP) and thereby increases amyloid-β levels. This molecular mechanism also regulates APP transcription in mice in vivo. Our data describe a novel signal transduction pathway in neurons whereby ApoE activates a non-canonical MAP kinase cascade that enhances APP transcription and amyloid-β synthesis.
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Affiliation(s)
- Yu-Wen Alvin Huang
- Department of Molecular and Cellular Physiology and Howard Hughes Medical Institute, Stanford University Medical School, Stanford, CA 94305, USA
| | - Bo Zhou
- Department of Molecular and Cellular Physiology and Howard Hughes Medical Institute, Stanford University Medical School, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University Medical School, Stanford, CA 94305, USA
| | - Marius Wernig
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University Medical School, Stanford, CA 94305, USA
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology and Howard Hughes Medical Institute, Stanford University Medical School, Stanford, CA 94305, USA.
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134
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Brace EJ, DiAntonio A. Models of axon regeneration in Drosophila. Exp Neurol 2017; 287:310-317. [PMID: 26996133 PMCID: PMC5026866 DOI: 10.1016/j.expneurol.2016.03.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 03/11/2016] [Accepted: 03/14/2016] [Indexed: 12/14/2022]
Abstract
Maintaining neuronal connectivity in the face of injury and disease is a major challenge for the nervous system. The great length of axons makes them particularly vulnerable to insult with dire consequences for neuronal function. In the peripheral nervous system there is a program of axonal regeneration that can reestablish connectivity. In the mammalian central nervous system, however, injured axons have little or no capacity to regenerate. The molecular mechanisms that promote axon regeneration have begun to be identified and many of the implicated pathways are evolutionarily conserved. Here we discuss Drosophila models of axonal regrowth, describe insights derived from these studies, and highlight future directions in the use of the fly for dissecting the mechanisms of axonal regeneration.
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Affiliation(s)
- E J Brace
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA, 63110
| | - Aaron DiAntonio
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA, 63110.
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135
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Baker ST, Grill B. Defining Minimal Binding Regions in Regulator of Presynaptic Morphology 1 (RPM-1) Using Caenorhabditis elegans Neurons Reveals Differential Signaling Complexes. J Biol Chem 2016; 292:2519-2530. [PMID: 27979965 DOI: 10.1074/jbc.m116.748004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 12/14/2016] [Indexed: 12/22/2022] Open
Abstract
The intracellular signaling protein regulator of presynaptic morphology 1 (RPM-1) is a conserved regulator of synapse formation and axon termination in Caenorhabditis elegans RPM-1 functions in a ubiquitin ligase complex with the F-box protein FSN-1 and functions through the microtubule binding protein RAE-1. Using a structure-function approach and positive selection for transgenic C. elegans, we explored the biochemical relationship between RPM-1, FSN-1, and RAE-1. This led to the identification of two new domains in RPM-1 that are sufficient for binding to FSN-1, called FSN-1 binding domain 2 (FBD2) and FBD3. Furthermore, we map the RAE-1 binding domain to a much smaller region of RPM-1. Point mutations in RPM-1 that reduce binding to RAE-1 did not affect FSN-1 binding, indicating that RPM-1 utilizes different biochemical mechanisms to bind these molecules. Analysis of RPM-1 protein complexes in the neurons of C. elegans elucidated two further discoveries: FSN-1 binds to RAE-1, and this interaction is not mediated by RPM-1, and RPM-1 binding to FSN-1 and RAE-1 reduces FSN-1·RAE-1 complex formation. These results indicate that RPM-1 uses different mechanisms to recruit FSN-1 and RAE-1 into independent signaling complexes in neurons.
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Affiliation(s)
- Scott T Baker
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458
| | - Brock Grill
- From the Department of Neuroscience, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458
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136
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McEwan DL, Feinbaum RL, Stroustrup N, Haas W, Conery AL, Anselmo A, Sadreyev R, Ausubel FM. Tribbles ortholog NIPI-3 and bZIP transcription factor CEBP-1 regulate a Caenorhabditis elegans intestinal immune surveillance pathway. BMC Biol 2016; 14:105. [PMID: 27927200 PMCID: PMC5143455 DOI: 10.1186/s12915-016-0334-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 11/15/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Many pathogens secrete toxins that target key host processes resulting in the activation of immune pathways. The secreted Pseudomonas aeruginosa toxin Exotoxin A (ToxA) disrupts intestinal protein synthesis, which triggers the induction of a subset of P. aeruginosa-response genes in the nematode Caenorhabditis elegans. RESULTS We show here that one ToxA-induced C. elegans gene, the Tribbles pseudokinase ortholog nipi-3, is essential for host survival following exposure to P. aeruginosa or ToxA. We find that NIPI-3 mediates the post-developmental expression of intestinal immune genes and proteins and primarily functions in parallel to known immune pathways, including p38 MAPK signaling. Through mutagenesis screening, we identify mutants of the bZIP C/EBP transcription factor cebp-1 that suppress the hypersusceptibility defects of nipi-3 mutants. CONCLUSIONS NIPI-3 is a negative regulator of CEBP-1, which in turn negatively regulates protective immune mechanisms. This pathway represents a previously unknown innate immune signaling pathway in intestinal epithelial cells that is involved in the surveillance of cellular homeostasis. Because NIPI-3 and CEBP-1 are also essential for C. elegans development, NIPI-3 is analogous to other key innate immune signaling molecules such as the Toll receptors in Drosophila that have an independent role during development.
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Affiliation(s)
- Deborah L. McEwan
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA USA
- Department of Genetics, Harvard Medical School, Boston, MA USA
| | - Rhonda L. Feinbaum
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA USA
- Department of Genetics, Harvard Medical School, Boston, MA USA
| | | | - Wilhelm Haas
- Center for Cancer Research, Massachusetts General Hospital, Boston, MA USA
| | - Annie L. Conery
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA USA
- Department of Genetics, Harvard Medical School, Boston, MA USA
- Present Address: Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, MA USA
| | - Anthony Anselmo
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA USA
- Department of Genetics, Harvard Medical School, Boston, MA USA
| | - Ruslan Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA USA
- Department of Genetics, Harvard Medical School, Boston, MA USA
- Department of Pathology, Massachusetts General Hospital, Boston, MA USA
| | - Frederick M. Ausubel
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA USA
- Department of Genetics, Harvard Medical School, Boston, MA USA
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137
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Kim KW, Thakur N, Piggott CA, Omi S, Polanowska J, Jin Y, Pujol N. Coordinated inhibition of C/EBP by Tribbles in multiple tissues is essential for Caenorhabditis elegans development. BMC Biol 2016; 14:104. [PMID: 27927209 PMCID: PMC5141650 DOI: 10.1186/s12915-016-0320-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 10/19/2016] [Indexed: 01/15/2023] Open
Abstract
Background Tribbles proteins are conserved pseudokinases that function to control kinase signalling and transcription in diverse biological processes. Abnormal function in human Tribbles has been implicated in a number of diseases including leukaemia, metabolic syndromes and cardiovascular diseases. Caenorhabditis elegans Tribbles NIPI-3 was previously shown to activate host defense upon infection by promoting the conserved PMK-1/p38 mitogen-activated protein kinase (MAPK) signalling pathway. Despite the prominent role of Tribbles proteins in many species, our knowledge of their mechanism of action is fragmented, and the in vivo functional relevance of their interactions with other proteins remains largely unknown. Results Here, by characterizing nipi-3 null mutants, we show that nipi-3 is essential for larval development and viability. Through analyses of genetic suppressors of nipi-3 null mutant lethality, we show that NIPI-3 negatively controls PMK-1/p38 signalling via transcriptional repression of the C/EBP transcription factor CEBP-1. We identified CEBP-1’s transcriptional targets by ChIP-seq analyses and found them to be enriched in genes involved in development and stress responses. Unlike its cell-autonomous role in innate immunity, NIPI-3 is required in multiple tissues to control organismal development. Conclusions Together, our data uncover an unprecedented crosstalk involving multiple tissues, in which NIPI-3 acts as a master regulator to inhibit CEBP-1 and the PMK-1/p38 MAPK pathway. In doing so, it keeps innate immunity in check and ensures proper organismal development. Electronic supplementary material The online version of this article (doi:10.1186/s12915-016-0320-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kyung Won Kim
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA.
| | - Nishant Thakur
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France
| | - Christopher A Piggott
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Shizue Omi
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France
| | - Jolanta Polanowska
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, 92093, USA. .,Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA, 92093, USA.
| | - Nathalie Pujol
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Inserm, CNRS, Marseille, France.
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138
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Chen L, Nye DM, Stone MC, Weiner AT, Gheres KW, Xiong X, Collins CA, Rolls MM. Mitochondria and Caspases Tune Nmnat-Mediated Stabilization to Promote Axon Regeneration. PLoS Genet 2016; 12:e1006503. [PMID: 27923046 PMCID: PMC5173288 DOI: 10.1371/journal.pgen.1006503] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 12/20/2016] [Accepted: 11/22/2016] [Indexed: 11/24/2022] Open
Abstract
Axon injury can lead to several cell survival responses including increased stability and axon regeneration. Using an accessible Drosophila model system, we investigated the regulation of injury responses and their relationship. Axon injury stabilizes the rest of the cell, including the entire dendrite arbor. After axon injury we found mitochondrial fission in dendrites was upregulated, and that reducing fission increased stabilization or neuroprotection (NP). Thus axon injury seems to both turn on NP, but also dampen it by activating mitochondrial fission. We also identified caspases as negative regulators of axon injury-mediated NP, so mitochondrial fission could control NP through caspase activation. In addition to negative regulators of NP, we found that nicotinamide mononucleotide adenylyltransferase (Nmnat) is absolutely required for this type of NP. Increased microtubule dynamics, which has previously been associated with NP, required Nmnat. Indeed Nmnat overexpression was sufficient to induce NP and increase microtubule dynamics in the absence of axon injury. DLK, JNK and fos were also required for NP. Because NP occurs before axon regeneration, and NP seems to be actively downregulated, we tested whether excessive NP might inhibit regeneration. Indeed both Nmnat overexpression and caspase reduction reduced regeneration. In addition, overexpression of fos or JNK extended the timecourse of NP and dampened regeneration in a Nmnat-dependent manner. These data suggest that NP and regeneration are conflicting responses to axon injury, and that therapeutic strategies that boost NP may reduce regeneration. Unlike many other cell types, most neurons last a lifetime. When injured, these cells often activate survival and repair strategies rather than dying. One such response is regeneration of the axon after it is injured. Axon regeneration is a conserved process activated by the same signaling cascade in worms, flies and mammals. Surprisingly we find that this signaling cascade first initiates a different response. This first response stabilizes the cell, and its downregulation by mitochondrial fission and caspases allows for maximum regeneration at later times. We propose that neurons respond to axon injury in a multi-step process with an early lock-down phase in which the cell is stabilized, followed by a more plastic state in which regeneration is maximized.
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Affiliation(s)
- Li Chen
- Huck Institutes of the Life Sciences, and Biochemistry and Molecular Biology,The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Derek M. Nye
- Huck Institutes of the Life Sciences, and Biochemistry and Molecular Biology,The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Michelle C. Stone
- Huck Institutes of the Life Sciences, and Biochemistry and Molecular Biology,The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Alexis T. Weiner
- Huck Institutes of the Life Sciences, and Biochemistry and Molecular Biology,The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Kyle W. Gheres
- Huck Institutes of the Life Sciences, and Biochemistry and Molecular Biology,The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Xin Xiong
- Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Catherine A. Collins
- Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Melissa M. Rolls
- Huck Institutes of the Life Sciences, and Biochemistry and Molecular Biology,The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail:
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139
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Chisholm AD, Hutter H, Jin Y, Wadsworth WG. The Genetics of Axon Guidance and Axon Regeneration in Caenorhabditis elegans. Genetics 2016; 204:849-882. [PMID: 28114100 PMCID: PMC5105865 DOI: 10.1534/genetics.115.186262] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 09/06/2016] [Indexed: 11/18/2022] Open
Abstract
The correct wiring of neuronal circuits depends on outgrowth and guidance of neuronal processes during development. In the past two decades, great progress has been made in understanding the molecular basis of axon outgrowth and guidance. Genetic analysis in Caenorhabditis elegans has played a key role in elucidating conserved pathways regulating axon guidance, including Netrin signaling, the slit Slit/Robo pathway, Wnt signaling, and others. Axon guidance factors were first identified by screens for mutations affecting animal behavior, and by direct visual screens for axon guidance defects. Genetic analysis of these pathways has revealed the complex and combinatorial nature of guidance cues, and has delineated how cues guide growth cones via receptor activity and cytoskeletal rearrangement. Several axon guidance pathways also affect directed migrations of non-neuronal cells in C. elegans, with implications for normal and pathological cell migrations in situations such as tumor metastasis. The small number of neurons and highly stereotyped axonal architecture of the C. elegans nervous system allow analysis of axon guidance at the level of single identified axons, and permit in vivo tests of prevailing models of axon guidance. C. elegans axons also have a robust capacity to undergo regenerative regrowth after precise laser injury (axotomy). Although such axon regrowth shares some similarities with developmental axon outgrowth, screens for regrowth mutants have revealed regeneration-specific pathways and factors that were not identified in developmental screens. Several areas remain poorly understood, including how major axon tracts are formed in the embryo, and the function of axon regeneration in the natural environment.
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Affiliation(s)
| | - Harald Hutter
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, and
- Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, California 92093
- Department of Pathology and Laboratory Medicine, Howard Hughes Medical Institute, Chevy Chase, Maryland, and
| | - William G Wadsworth
- Department of Pathology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
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140
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Byrne AB, McWhirter RD, Sekine Y, Strittmatter SM, Miller DM, Hammarlund M. Inhibiting poly(ADP-ribosylation) improves axon regeneration. eLife 2016; 5. [PMID: 27697151 PMCID: PMC5050021 DOI: 10.7554/elife.12734] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 09/03/2016] [Indexed: 11/13/2022] Open
Abstract
The ability of a neuron to regenerate its axon after injury depends in part on its intrinsic regenerative potential. Here, we identify novel intrinsic regulators of axon regeneration: poly(ADP-ribose) glycohodrolases (PARGs) and poly(ADP-ribose) polymerases (PARPs). PARGs, which remove poly(ADP-ribose) from proteins, act in injured C. elegans GABA motor neurons to enhance axon regeneration. PARG expression is regulated by DLK signaling, and PARGs mediate DLK function in enhancing axon regeneration. Conversely, PARPs, which add poly(ADP-ribose) to proteins, inhibit axon regeneration of both C. elegans GABA neurons and mammalian cortical neurons. Furthermore, chemical PARP inhibitors improve axon regeneration when administered after injury. Our results indicate that regulation of poly(ADP-ribose) levels is a critical function of the DLK regeneration pathway, that poly-(ADP ribosylation) inhibits axon regeneration across species, and that chemical inhibition of PARPs can elicit axon regeneration.
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Affiliation(s)
- Alexandra B Byrne
- Department of Genetics, Yale University School of Medicine, New Haven, United States.,Department of Neuroscience, Yale University School of Medicine, New Haven, United States.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, United States
| | - Rebecca D McWhirter
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States.,Program in Neuroscience, Vanderbilt University, Nashville, United States
| | - Yuichi Sekine
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, United States.,Department of Neurology, Yale University School of Medicine, New Haven, United States
| | - Stephen M Strittmatter
- Department of Neuroscience, Yale University School of Medicine, New Haven, United States.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, United States.,Department of Neurology, Yale University School of Medicine, New Haven, United States
| | - David M Miller
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States.,Program in Neuroscience, Vanderbilt University, Nashville, United States
| | - Marc Hammarlund
- Department of Genetics, Yale University School of Medicine, New Haven, United States.,Department of Neuroscience, Yale University School of Medicine, New Haven, United States.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, United States
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141
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Lockhead D, Schwarz EM, O'Hagan R, Bellotti S, Krieg M, Barr MM, Dunn AR, Sternberg PW, Goodman MB. The tubulin repertoire of C. elegans sensory neurons and its context-dependent role in process outgrowth. Mol Biol Cell 2016; 27:mbc.E16-06-0473. [PMID: 27654945 PMCID: PMC5170555 DOI: 10.1091/mbc.e16-06-0473] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/12/2016] [Accepted: 09/15/2016] [Indexed: 12/21/2022] Open
Abstract
Microtubules contribute to many cellular processes, including transport, signaling, and chromosome separation during cell division (Kapitein and Hoogenraad, 2015). They are comprised of αβ-tubulin heterodimers arranged into linear protofilaments and assembled into tubes. Eukaryotes express multiple tubulin isoforms (Gogonea et al., 1999), and there has been a longstanding debate as to whether the isoforms are redundant or perform specialized roles as part of a tubulin code (Fulton and Simpson, 1976). Here, we use the well-characterized touch receptor neurons (TRNs) of Caenorhabditis elegans to investigate this question, through genetic dissection of process outgrowth both in vivo and in vitro With single-cell RNA-seq, we compare transcription profiles for TRNs with those of two other sensory neurons, and present evidence that each sensory neuron expresses a distinct palette of tubulin genes. In the TRNs, we analyze process outgrowth and show that four tubulins (tba-1, tba-2, tbb-1, and tbb-2) function partially or fully redundantly, while two others (mec-7 and mec-12) perform specialized, context-dependent roles. Our findings support a model in which sensory neurons express overlapping subsets of tubulin genes whose functional redundancy varies between cell types and in vivo and in vitro contexts.
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Affiliation(s)
- Dean Lockhead
- *Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
| | - Erich M Schwarz
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853
| | - Robert O'Hagan
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854
| | - Sebastian Bellotti
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854
| | - Michael Krieg
- *Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
| | - Maureen M Barr
- Department of Genetics, Rutgers, The State University of New Jersey, Piscataway, NJ 08854
| | - Alexander R Dunn
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305 Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Paul W Sternberg
- Howard Hughes Medical Institute and Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Miriam B Goodman
- *Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
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142
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Rao K, Stone MC, Weiner AT, Gheres KW, Zhou C, Deitcher DL, Levitan ES, Rolls MM. Spastin, atlastin, and ER relocalization are involved in axon but not dendrite regeneration. Mol Biol Cell 2016; 27:3245-3256. [PMID: 27605706 PMCID: PMC5170858 DOI: 10.1091/mbc.e16-05-0287] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 08/31/2016] [Indexed: 12/19/2022] Open
Abstract
A Drosophila model system is used to show that the hereditary spastic paraplegia proteins spastin and atlastin help axons but not dendrites regenerate. The endoplasmic reticulum concentrates at tips of regenerating axons but not dendrites, and this depends on spastin and atlastin. Mutations in >50 genes, including spastin and atlastin, lead to hereditary spastic paraplegia (HSP). We previously demonstrated that reduction of spastin leads to a deficit in axon regeneration in a Drosophila model. Axon regeneration was similarly impaired in neurons when HSP proteins atlastin, seipin, and spichthyin were reduced. Impaired regeneration was dependent on genetic background and was observed when partial reduction of HSP proteins was combined with expression of dominant-negative microtubule regulators, suggesting that HSP proteins work with microtubules to promote regeneration. Microtubule rearrangements triggered by axon injury were, however, normal in all genotypes. We examined other markers to identify additional changes associated with regeneration. Whereas mitochondria, endosomes, and ribosomes did not exhibit dramatic repatterning during regeneration, the endoplasmic reticulum (ER) was frequently concentrated near the tip of the growing axon. In atlastin RNAi and spastin mutant animals, ER accumulation near single growing axon tips was impaired. ER tip concentration was observed only during axon regeneration and not during dendrite regeneration. In addition, dendrite regeneration was unaffected by reduction of spastin or atlastin. We propose that the HSP proteins spastin and atlastin promote axon regeneration by coordinating concentration of the ER and microtubules at the growing axon tip.
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Affiliation(s)
- Kavitha Rao
- Biochemistry and Molecular Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - Michelle C Stone
- Biochemistry and Molecular Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - Alexis T Weiner
- Biochemistry and Molecular Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802.,Molecular, Cellular and Integrative Biosciences Graduate Program, Pennsylvania State University, University Park, PA 16802
| | - Kyle W Gheres
- Biochemistry and Molecular Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802.,Molecular, Cellular and Integrative Biosciences Graduate Program, Pennsylvania State University, University Park, PA 16802
| | - Chaoming Zhou
- Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261
| | | | - Edwin S Levitan
- Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261
| | - Melissa M Rolls
- Biochemistry and Molecular Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802 .,Molecular, Cellular and Integrative Biosciences Graduate Program, Pennsylvania State University, University Park, PA 16802
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143
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Byrne AB, Hammarlund M. Axon regeneration in C. elegans: Worming our way to mechanisms of axon regeneration. Exp Neurol 2016; 287:300-309. [PMID: 27569538 DOI: 10.1016/j.expneurol.2016.08.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/19/2016] [Accepted: 08/24/2016] [Indexed: 12/12/2022]
Abstract
How axons repair themselves after injury is a fundamental question in neurobiology. With its conserved genome, relatively simple nervous system, and transparent body, C. elegans has recently emerged as a productive model to uncover the cellular mechanisms that regulate and execute axon regeneration. In this review, we discuss the strengths and weaknesses of the C. elegans model of regeneration. We explore the technical advances that enable the use of C. elegans for in vivo regeneration studies, review findings in C. elegans that have contributed to our understanding of the regeneration response across species, discuss the potential of C. elegans research to provide insight into mechanisms that function in the injured mammalian nervous system, and present potential future directions of axon regeneration research using C. elegans.
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Affiliation(s)
- Alexandra B Byrne
- Department of Genetics, Yale University School of Medicine, New Haven, CT, United States; Department of Neuroscience, Yale University School of Medicine, New Haven, CT, United States
| | - Marc Hammarlund
- Department of Genetics, Yale University School of Medicine, New Haven, CT, United States; Department of Neuroscience, Yale University School of Medicine, New Haven, CT, United States.
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144
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Leucine Zipper-bearing Kinase promotes axon growth in mammalian central nervous system neurons. Sci Rep 2016; 6:31482. [PMID: 27511108 PMCID: PMC4980599 DOI: 10.1038/srep31482] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 07/04/2016] [Indexed: 11/11/2022] Open
Abstract
Leucine Zipper-bearing Kinase (LZK/MAP3K13) is a member of the mixed lineage kinase family with high sequence identity to Dual Leucine Zipper Kinase (DLK/MAP3K12). While DLK is established as a key regulator of axonal responses to injury, the role of LZK in mammalian neurons is poorly understood. By gain- and loss-of-function analyses in neuronal cultures, we identify LZK as a novel positive regulator of axon growth. LZK signals specifically through MKK4 and JNKs among MAP2Ks and MAPKs respectively in neuronal cells, with JNK activity positively regulating LZK protein levels. Neuronal maturation or activity deprivation activates the LZK-MKK4-JNK pathway. LZK and DLK share commonalities in signaling, regulation, and effects on axon extension. Furthermore, LZK-dependent regulation of DLK protein expression and the lack of additive effects on axon growth upon co-manipulation suggest complex functional interaction and cross-regulation between these two kinases. Together, our data support the possibility for two structurally related MAP3Ks to work in concert to mediate axonal responses to external insult or injury in mammalian CNS neurons.
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145
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Soulavie F, Sundaram MV. Auto-fusion and the shaping of neurons and tubes. Semin Cell Dev Biol 2016; 60:136-145. [PMID: 27436685 DOI: 10.1016/j.semcdb.2016.07.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 07/15/2016] [Accepted: 07/15/2016] [Indexed: 12/14/2022]
Abstract
Cells adopt specific shapes that are necessary for specific functions. For example, some neurons extend elaborate arborized dendrites that can contact multiple targets. Epithelial and endothelial cells can form tiny seamless unicellular tubes with an intracellular lumen. Recent advances showed that cells can auto-fuse to acquire those specific shapes. During auto-fusion, a cell merges two parts of its own plasma membrane. In contrast to cell-cell fusion or macropinocytic fission, which result in the merging or formation of two separate membrane bound compartments, auto-fusion preserves one compartment, but changes its shape. The discovery of auto-fusion in C. elegans was enabled by identification of specific protein fusogens, EFF-1 and AFF-1, that mediate cell-cell fusion. Phenotypic characterization of eff-1 and aff-1 mutants revealed that fusogen-mediated fusion of two parts of the same cell can be used to sculpt dendritic arbors, reconnect two parts of an axon after injury, or form a hollow unicellular tube. Similar auto-fusion events recently were detected in vertebrate cells, suggesting that auto-fusion could be a widely used mechanism for shaping neurons and tubes.
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Affiliation(s)
- Fabien Soulavie
- Department of Genetics, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104,United States
| | - Meera V Sundaram
- Department of Genetics, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104,United States.
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146
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Feoktistov AI, Herman TG. Wallenda/DLK protein levels are temporally downregulated by Tramtrack69 to allow R7 growth cones to become stationary boutons. Development 2016; 143:2983-93. [PMID: 27402706 DOI: 10.1242/dev.134403] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 06/23/2016] [Indexed: 11/20/2022]
Abstract
Dual leucine zipper kinase (DLK) promotes growth cone motility and must be restrained to ensure normal development. PHR (Pam/Highwire/RPM-1) ubiquitin ligases therefore target DLK for degradation unless axon injury occurs. Overall DLK levels decrease during development, but how DLK levels are regulated within a developing growth cone has not been examined. We analyzed the expression of the fly DLK Wallenda (Wnd) in R7 photoreceptor growth cones as they halt at their targets and become presynaptic boutons. We found that Wnd protein levels are repressed by the PHR protein Highwire (Hiw) during R7 growth cone halting, as has been observed in other systems. However, as R7 growth cones become boutons, Wnd levels are further repressed by a temporally expressed transcription factor, Tramtrack69 (Ttk69). Previously unobserved negative feedback from JNK also contributes to Wnd repression at both time points. We conclude that neurons deploy additional mechanisms to downregulate DLK as they form stable, synaptic connections. We use live imaging to probe the effects of Wnd and Ttk69 on R7 bouton development and conclude that Ttk69 coordinates multiple regulators of this process.
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Affiliation(s)
- Alexander I Feoktistov
- Institute of Molecular Biology, Department of Biology, University of Oregon, Eugene, OR 97403, USA
| | - Tory G Herman
- Institute of Molecular Biology, Department of Biology, University of Oregon, Eugene, OR 97403, USA
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147
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Hao Y, Frey E, Yoon C, Wong H, Nestorovski D, Holzman LB, Giger RJ, DiAntonio A, Collins C. An evolutionarily conserved mechanism for cAMP elicited axonal regeneration involves direct activation of the dual leucine zipper kinase DLK. eLife 2016; 5. [PMID: 27268300 PMCID: PMC4896747 DOI: 10.7554/elife.14048] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 05/12/2016] [Indexed: 11/13/2022] Open
Abstract
A broadly known method to stimulate the growth potential of axons is to elevate intracellular levels of cAMP, however the cellular pathway(s) that mediate this are not known. Here we identify the Dual Leucine-zipper Kinase (DLK, Wnd in Drosophila) as a critical target and effector of cAMP in injured axons. DLK/Wnd is thought to function as an injury ‘sensor’, as it becomes activated after axonal damage. Our findings in both Drosophila and mammalian neurons indicate that the cAMP effector kinase PKA is a conserved and direct upstream activator of Wnd/DLK. PKA is required for the induction of Wnd signaling in injured axons, and DLK is essential for the regenerative effects of cAMP in mammalian DRG neurons. These findings link two important mediators of responses to axonal injury, DLK/Wnd and cAMP/PKA, into a unified and evolutionarily conserved molecular pathway for stimulating the regenerative potential of injured axons. DOI:http://dx.doi.org/10.7554/eLife.14048.001 Adult mammals typically cannot repair damage to the nerve fibers in their brain or spinal cord. This is because these nerve cells cannot generally grow new nerve fibers. However this inability to regenerate nerve fibers is not set in stone. Instead, it can be unlocked by a second injury in nerves elsewhere in the body, the so-called “peripheral nervous system”. This process relies on an enzyme called DLK, which becomes activated in damaged nerve fibers. But how does DLK ‘sense’ damage to nerve fibers? Injuring the peripheral nervous system causes the levels of a molecule called cAMP to increase in the damaged nerve cells, and the elevated cAMP levels stimulate the nerve fibers to regenerate. However, it was not known if cAMP activates DLK, or if the two act independently of each other. By looking at the regeneration of damaged nerve fibers in fruit fly larvae, Hao et al. now show that the cAMP and DLK signaling pathways are clearly linked. Further experiments with nerve cells from mice and human cells revealed more detail about this link. Together the results showed that another enzyme called PKA activates DLK directly when cAMP levels are high. These findings reveal a unified pathway that is the key to unlocking the regenerative potential of injured nerve fibers, which has been conserved for hundreds of millions of years of evolution. Further work could now ask if the DLK enzyme is involved in the other known roles of cAMP signaling in nerve cells; or if cAMP and PKA activate DLK in other forms of nerve damage, including injuries where nerve fibers normally fail to regenerate. DOI:http://dx.doi.org/10.7554/eLife.14048.002
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Affiliation(s)
- Yan Hao
- Department of Molecular Cellular and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Erin Frey
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
| | - Choya Yoon
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Hetty Wong
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Douglas Nestorovski
- Department of Molecular Cellular and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Lawrence B Holzman
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Roman J Giger
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, United States.,Department of Neurology, University of Michigan School of Medicine, Ann Arbor, United States
| | - Aaron DiAntonio
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
| | - Catherine Collins
- Department of Molecular Cellular and Developmental Biology, University of Michigan, Ann Arbor, United States
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Pastuhov SI, Matsumoto K, Hisamoto N. Endocannabinoid signaling regulates regenerative axon navigation in Caenorhabditis elegans via the GPCRs NPR-19 and NPR-32. Genes Cells 2016; 21:696-705. [PMID: 27193416 DOI: 10.1111/gtc.12377] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 04/17/2016] [Indexed: 02/05/2023]
Abstract
The axon regeneration ability of neurons depends on the interplay of factors that promote and inhibit regeneration. In Caenorhabditis elegans, axon regeneration is promoted by the JNK MAP kinase (MAPK) pathway. Previously, we found that the endocannabinoid anandamide (AEA) inhibits the axon regeneration response of motor neurons after laser axotomy by suppressing the JNK signaling pathway. Here, we show that the G-protein-coupled receptors (GPCRs) NPR-19 and NPR-32 inhibit axon regeneration in response to AEA. Furthermore, we show that sensory neuron expression of the nape-1 gene, which encodes an enzyme synthesizing AEA, causes the regenerating motor axons to avoid sensory neurons and this avoidant response depends on NPR-19 and NPR-32. These results indicate that the navigation of regenerating axons is modulated by the action of AEA on NPR-19/32 GPCRs.
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Affiliation(s)
- Strahil Iv Pastuhov
- Division of Biological Science, Graduate school of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Kunihiro Matsumoto
- Division of Biological Science, Graduate school of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan
| | - Naoki Hisamoto
- Division of Biological Science, Graduate school of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan
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149
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He Z, Jin Y. Intrinsic Control of Axon Regeneration. Neuron 2016; 90:437-51. [DOI: 10.1016/j.neuron.2016.04.022] [Citation(s) in RCA: 337] [Impact Index Per Article: 42.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 03/10/2016] [Accepted: 04/13/2016] [Indexed: 01/12/2023]
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150
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D’Souza SA, Rajendran L, Bagg R, Barbier L, van Pel DM, Moshiri H, Roy PJ. The MADD-3 LAMMER Kinase Interacts with a p38 MAP Kinase Pathway to Regulate the Display of the EVA-1 Guidance Receptor in Caenorhabditis elegans. PLoS Genet 2016; 12:e1006010. [PMID: 27123983 PMCID: PMC4849719 DOI: 10.1371/journal.pgen.1006010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 04/05/2016] [Indexed: 11/25/2022] Open
Abstract
The proper display of transmembrane receptors on the leading edge of migrating cells and cell extensions is essential for their response to guidance cues. We previously discovered that MADD-4, which is an ADAMTSL secreted by motor neurons in Caenorhabditis elegans, interacts with an UNC-40/EVA-1 co-receptor complex on muscles to attract plasma membrane extensions called muscle arms. In nematodes, the muscle arm termini harbor the post-synaptic elements of the neuromuscular junction. Through a forward genetic screen for mutants with disrupted muscle arm extension, we discovered that a LAMMER kinase, which we call MADD-3, is required for the proper display of the EVA-1 receptor on the muscle’s plasma membrane. Without MADD-3, EVA-1 levels decrease concomitantly with a reduction of the late-endosomal marker RAB-7. Through a genetic suppressor screen, we found that the levels of EVA-1 and RAB-7 can be restored in madd-3 mutants by eliminating the function of a p38 MAP kinase pathway. We also found that EVA-1 and RAB-7 will accumulate in madd-3 mutants upon disrupting CUP-5, which is a mucolipin ortholog required for proper lysosome function. Together, our data suggests that the MADD-3 LAMMER kinase antagonizes the p38-mediated endosomal trafficking of EVA-1 to the lysosome. In this way, MADD-3 ensures that sufficient levels of EVA-1 are present to guide muscle arm extension towards the source of the MADD-4 guidance cue. In most animals, the physical meeting of the pre- and post-synaptic membranes of the neuromuscular junction occurs via axonal extension towards the muscle. In nematodes, however, motor axons do not extend towards the muscle and instead form a dorsal and ventral cord with relatively few branches. To make the physical connection, the body wall muscles extend membrane projections called muscle arms to the motor axons within the dorsal and ventral cords. Through previous genetic and biochemical analyses with the nematode C. elegans, we identified a neuronally-expressed muscle arm chemoattractant (MADD-4) and its muscle-expressed co-receptor complex (UNC-40/EVA-1). Here, we report our discovery of madd-3, which encodes a LAMMER kinase that is expressed in muscles to regulate muscle arm extension. Genetic analyses revealed that MADD-3 may inhibit a p38 MAP kinase pathway whose normal function is to decrease the abundance of the EVA-1 receptor. In the presence of MADD-3, the activity of the p38 pathway is relatively low, and EVA-1 levels are consequently relatively high. Without MADD-3, the p38 pathway is freed to decrease the abundance of EVA-1. The relationships that we have uncovered between MADD-3, the p38 Map Kinase pathway, and the EVA-1 receptor provide one explanation for the muscle arm defects observed in madd-3 mutants.
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Affiliation(s)
- Serena A. D’Souza
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- The Collaborative Programme in Developmental Biology, University of Toronto, Toronto, Ontario, Canada
| | - Luckshi Rajendran
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Rachel Bagg
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Louis Barbier
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Derek M. van Pel
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Houtan Moshiri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Peter J. Roy
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- The Collaborative Programme in Developmental Biology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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