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Intrinsic heterogeneity in axon regeneration. Biochem Soc Trans 2022; 50:1753-1762. [DOI: 10.1042/bst20220624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 11/01/2022] [Accepted: 11/07/2022] [Indexed: 11/18/2022]
Abstract
The nervous system is composed of a variety of neurons and glial cells with different morphology and functions. In the mammalian peripheral nervous system (PNS) or the lower vertebrate central nervous system (CNS), most neurons can regenerate extensively after axotomy, while the neurons in the mammalian CNS possess only limited regenerative ability. This heterogeneity is common within and across species. The studies about the transcriptomes after nerve injury in different animal models have revealed a series of molecular and cellular events that occurred in neurons after axotomy. However, responses of various types of neurons located in different positions of individuals were different remarkably. Thus, researchers aim to find the key factors that are conducive to regeneration, so as to provide the molecular basis for solving the regeneration difficulties after CNS injury. Here we review the heterogeneity of axonal regeneration among different cell subtypes in different animal models or the same organ, emphasizing the importance of comparative studies within and across species.
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2
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Staunton CA, Owen ED, Hemmings K, Vasilaki A, McArdle A, Barrett-Jolley R, Jackson MJ. Skeletal muscle transcriptomics identifies common pathways in nerve crush injury and ageing. Skelet Muscle 2022; 12:3. [PMID: 35093178 PMCID: PMC8800362 DOI: 10.1186/s13395-021-00283-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 11/24/2021] [Indexed: 12/16/2022] Open
Abstract
Motor unit remodelling involving repeated denervation and re-innervation occurs throughout life. The efficiency of this process declines with age contributing to neuromuscular deficits. This study investigated differentially expressed genes (DEG) in muscle following peroneal nerve crush to model motor unit remodelling in C57BL/6 J mice. Muscle RNA was isolated at 3 days post-crush, RNA libraries were generated using poly-A selection, sequenced and analysed using gene ontology and pathway tools. Three hundred thirty-four DEG were found in quiescent muscle from (26mnth) old compared with (4-6mnth) adult mice and these same DEG were present in muscle from adult mice following nerve crush. Peroneal crush induced 7133 DEG in muscles of adult and 699 DEG in muscles from old mice, although only one DEG (ZCCHC17) was found when directly comparing nerve-crushed muscles from old and adult mice. This analysis revealed key differences in muscle responses which may underlie the diminished ability of old mice to repair following nerve injury.
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Affiliation(s)
- C A Staunton
- MRC- Versus Arthritis Research Centre for Integrated research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, L7 8TX, UK
| | - E D Owen
- MRC- Versus Arthritis Research Centre for Integrated research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, L7 8TX, UK
| | - K Hemmings
- MRC- Versus Arthritis Research Centre for Integrated research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, L7 8TX, UK
| | - A Vasilaki
- MRC- Versus Arthritis Research Centre for Integrated research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, L7 8TX, UK
| | - A McArdle
- MRC- Versus Arthritis Research Centre for Integrated research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, L7 8TX, UK
| | - R Barrett-Jolley
- MRC- Versus Arthritis Research Centre for Integrated research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, L7 8TX, UK
| | - M J Jackson
- MRC- Versus Arthritis Research Centre for Integrated research into Musculoskeletal Ageing (CIMA), Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, L7 8TX, UK.
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Lin-Moore AT, Oyeyemi MJ, Hammarlund M. rab-27 acts in an intestinal pathway to inhibit axon regeneration in C. elegans. PLoS Genet 2021; 17:e1009877. [PMID: 34818334 PMCID: PMC8612575 DOI: 10.1371/journal.pgen.1009877] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 10/13/2021] [Indexed: 12/30/2022] Open
Abstract
Injured axons must regenerate to restore nervous system function, and regeneration is regulated in part by external factors from non-neuronal tissues. Many of these extrinsic factors act in the immediate cellular environment of the axon to promote or restrict regeneration, but the existence of long-distance signals regulating axon regeneration has not been clear. Here we show that the Rab GTPase rab-27 inhibits regeneration of GABAergic motor neurons in C. elegans through activity in the intestine. Re-expression of RAB-27, but not the closely related RAB-3, in the intestine of rab-27 mutant animals is sufficient to rescue normal regeneration. Several additional components of an intestinal neuropeptide secretion pathway also inhibit axon regeneration, including NPDC1/cab-1, SNAP25/aex-4, KPC3/aex-5, and the neuropeptide NLP-40, and re-expression of these genes in the intestine of mutant animals is sufficient to restore normal regeneration success. Additionally, NPDC1/cab-1 and SNAP25/aex-4 genetically interact with rab-27 in the context of axon regeneration inhibition. Together these data indicate that RAB-27-dependent neuropeptide secretion from the intestine inhibits axon regeneration, and point to distal tissues as potent extrinsic regulators of regeneration.
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Affiliation(s)
- Alexander T. Lin-Moore
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | | | - Marc Hammarlund
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, United States of America
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut, United States of America
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4
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CDK14 Promotes Axon Regeneration by Regulating the Noncanonical Wnt Signaling Pathway in a Kinase-Independent Manner. J Neurosci 2021; 41:8309-8320. [PMID: 34429379 PMCID: PMC8496196 DOI: 10.1523/jneurosci.0711-21.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 08/05/2021] [Accepted: 08/10/2021] [Indexed: 01/13/2023] Open
Abstract
The postinjury regenerative capacity of neurons is known to be mediated by a complex interaction of intrinsic regenerative pathways and external cues. In Caenorhabditis elegans, the initiation of axon regeneration is regulated by the nonmuscle myosin light chain-4 (MLC-4) phosphorylation signaling pathway. In this study, we have identified svh-16/cdk-14, a mammalian CDK14 homolog, as a positive regulator of axon regeneration in motor neurons. We then isolated the CDK-14-binding protein MIG-5/Disheveled (Dsh) and found that EGL-20/Wnt and the MIG-1/Frizzled receptor (Fz) are required for efficient axon regeneration. Further, we demonstrate that CDK-14 activates EPHX-1, the C. elegans homolog of the mammalian ephexin Rho-type GTPase guanine nucleotide exchange factor (GEF), in a kinase-independent manner. EPHX-1 functions as a GEF for the CDC-42 GTPase, inhibiting myosin phosphatase, which maintains MLC-4 phosphorylation. These results suggest that CDK14 activates the RhoGEF–CDC42–MLC phosphorylation axis in a noncanonical Wnt signaling pathway that promotes axon regeneration. SIGNIFICANCE STATEMENT Noncanonical Wnt signaling is mediated by Frizzled receptor (Fz), Disheveled (Dsh), Rho-type GTPase, and nonmuscle myosin light chain (MLC) phosphorylation. This study identified svh-16/cdk-14, which encodes a mammalian CDK14 homolog, as a regulator of axon regeneration in Caenorhabditis elegans motor neurons. We show that CDK-14 binds to MIG-5/Dsh, and that EGL-20/Wnt, MIG-1/Fz, and EPHX-1/RhoGEF are required for axon regeneration. The phosphorylation-mimetic MLC-4 suppressed axon regeneration defects in mig-1, cdk-14, and ephx-1 mutants. CDK-14 mediates kinase-independent activation of EPHX-1, which functions as a guanine nucleotide exchange factor for CDC-42 GTPase. Activated CDC-42 inactivates myosin phosphatase and thereby maintains MLC phosphorylation. Thus, the noncanonical Wnt signaling pathway controls axon regeneration via the CDK-14–EPHX-1–CDC-42–MLC phosphorylation axis.
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Tzouanas CN, Kim S, Badhiwala KN, Avants BW, Robinson JT. Hydra vulgaris shows stable responses to thermal stimulation despite large changes in the number of neurons. iScience 2021; 24:102490. [PMID: 34095784 PMCID: PMC8164038 DOI: 10.1016/j.isci.2021.102490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/03/2021] [Accepted: 04/27/2021] [Indexed: 11/27/2022] Open
Abstract
Many animals that lose neural tissue to injury or disease can maintain behavioral repertoires by regenerating new neurons or reorganizing existing neural circuits. However, most neuroscience small model organisms lack this high degree of neural plasticity. We show that Hydra vulgaris can maintain stable sensory-motor behaviors despite 2-fold changes in neuron count, due to naturally occurring size variation or surgical resection. Specifically, we find that both behavioral and neural responses to rapid temperature changes are maintained following these perturbations. We further describe possible mechanisms for the observed neural activity and argue that Hydra's radial symmetry may allow it to maintain stable behaviors when changes in the numbers of neurons do not selectively eliminate any specific neuronal cell type. These results suggest that Hydra provides a powerful model for studying how animals maintain stable sensory-motor responses within dynamic neural circuits and may lead to the development of general principles for injury-tolerant neural architectures. Thermal stimulation drives temperature-dependent firing rate in specific Hydra neurons Hydra show stable neural responses to temperature despite 2× decrease in neuron count Injury tolerance of Hydra offers model for stable neural architecture
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Affiliation(s)
| | - Soonyoung Kim
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Krishna N Badhiwala
- Department of Bioengineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Benjamin W Avants
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Jacob T Robinson
- Department of Bioengineering, Rice University, 6100 Main Street, Houston, TX 77005, USA.,Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA.,Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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6
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Kalichamy SS, Alcantara AV, Kim BS, Park J, Yoon KH, Lee JI. Muscle and epidermal contributions of the structural protein β-spectrin promote hypergravity-induced motor neuron axon defects in C. elegans. Sci Rep 2020; 10:21214. [PMID: 33273580 PMCID: PMC7713079 DOI: 10.1038/s41598-020-78414-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 11/23/2020] [Indexed: 11/09/2022] Open
Abstract
Biology is adapted to Earth's gravity force, and the long-term effects of varying gravity on the development of animals is unclear. Previously, we reported that high gravity, called hypergravity, increases defects in the development of motor neuron axons in the nematode Caenorhabditis elegans. Here, we show that a mutation in the unc-70 gene that encodes the cytoskeletal β-spectrin protein suppresses hypergravity-induced axon defects. UNC-70 expression is required in both muscle and epidermis to promote the axon defects in high gravity. We reveal that the location of axon defects is correlated to the size of the muscle cell that the axon traverses. We also show that mutations that compromise key proteins of hemidesmosomal structures suppress hypergravity-induced axon defects. These hemidesmosomal structures play a crucial role in coupling mechanical force between the muscle, epidermis and the external cuticle. We speculate a model in which the rigid organization of muscle, epidermal and cuticular layers under high gravity pressure compresses the narrow axon migration pathways in the extracellular matrix hindering proper axon pathfinding of motor neurons.
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Affiliation(s)
- Saraswathi S Kalichamy
- Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Mirae Campus 304, 1 Yonseidae-gil, Wonju, Gangwon-do, 26493, South Korea
| | - Alfredo V Alcantara
- Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Mirae Campus 304, 1 Yonseidae-gil, Wonju, Gangwon-do, 26493, South Korea
| | - Ban-Seok Kim
- Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Mirae Campus 304, 1 Yonseidae-gil, Wonju, Gangwon-do, 26493, South Korea
| | - Junsoo Park
- Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Mirae Campus 304, 1 Yonseidae-gil, Wonju, Gangwon-do, 26493, South Korea
| | - Kyoung-Hye Yoon
- Department of Physiology, Mitohormesis Research Center, Yonsei University Wonju College of Medicine, Wonju, Gangwon-do, 26426, South Korea.
| | - Jin I Lee
- Division of Biological Science and Technology, College of Science and Technology, Yonsei University, Mirae Campus 304, 1 Yonseidae-gil, Wonju, Gangwon-do, 26493, South Korea.
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Sutherland TC, Geoffroy CG. The Influence of Neuron-Extrinsic Factors and Aging on Injury Progression and Axonal Repair in the Central Nervous System. Front Cell Dev Biol 2020; 8:190. [PMID: 32269994 PMCID: PMC7109259 DOI: 10.3389/fcell.2020.00190] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/06/2020] [Indexed: 12/21/2022] Open
Abstract
In the aging western population, the average age of incidence for spinal cord injury (SCI) has increased, as has the length of survival of SCI patients. This places great importance on understanding SCI in middle-aged and aging patients. Axon regeneration after injury is an area of study that has received substantial attention and made important experimental progress, however, our understanding of how aging affects this process, and any therapeutic effort to modulate repair, is incomplete. The growth and regeneration of axons is mediated by both neuron intrinsic and extrinsic factors. In this review we explore some of the key extrinsic influences on axon regeneration in the literature, focusing on inflammation and astrogliosis, other cellular responses, components of the extracellular matrix, and myelin proteins. We will describe how each element supports the contention that axonal growth after injury in the central nervous system shows an age-dependent decline, and how this may affect outcomes after a SCI.
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Affiliation(s)
- Theresa C Sutherland
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, Bryan, TX, United States
| | - Cédric G Geoffroy
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, Bryan, TX, United States
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8
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Nazri MUIA, Idris I, Ross O, Ismail WIW. Neurological Disorder Brain Model: A Lesson from Marine Worms (Annelida: Polychaeta). Malays J Med Sci 2019; 26:5-18. [PMID: 31908583 PMCID: PMC6939724 DOI: 10.21315/mjms2019.26.6.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Accepted: 07/09/2019] [Indexed: 12/25/2022] Open
Abstract
The incidence of neurodegenerative diseases is directly proportional to age. The prevalence of non-communicable diseases, for example, Alzheimer's and Parkinson's, is expected to rise in the coming years. Understanding the etiopathology of these diseases is a crucial step that needs to be taken to develop drugs for their treatment. Animal models are being increasingly used to expand the knowledge and understanding on neurodegenerative diseases. Marine worms, known as polychaetes (phylum Annelida), which are abundantly and frequently found in benthic environments, possess a simple yet complete nervous system (including a true brain that is centralised and specialised) compared to other annelids. Hence, polychaetes can potentially be the next candidate for a nerve disease model. The ability to activate the entire nervous system regeneration (NSR) is among the remarkable features of many polychaetes species. However, the information on NSR in polychaetes and how it can potentially model neurodegenerative diseases in humans is still lacking. By exploring such studies, we may eventually be able to circumvent the developmental constraints that limit NSR in the human nervous system. This article is intended to briefly review responsible mechanisms and signalling pathways of NSR in marine polychaetes and to make a comparison with other established models of neurodegenerative disease.
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Affiliation(s)
| | - Izwandy Idris
- Institute of Oceanography and Environment, Universiti Malaysia Terengganu, Terengganu, Malaysia
| | - Othman Ross
- Institute of Oceanography and Environment, Universiti Malaysia Terengganu, Terengganu, Malaysia
| | - Wan Iryani Wan Ismail
- Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, Terengganu, Malaysia
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9
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Andrusiak MG, Sharifnia P, Lyu X, Wang Z, Dickey AM, Wu Z, Chisholm AD, Jin Y. Inhibition of Axon Regeneration by Liquid-like TIAR-2 Granules. Neuron 2019; 104:290-304.e8. [PMID: 31378567 PMCID: PMC6813885 DOI: 10.1016/j.neuron.2019.07.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 05/19/2019] [Accepted: 07/02/2019] [Indexed: 12/21/2022]
Abstract
Phase separation into liquid-like compartments is an emerging property of proteins containing prion-like domains (PrLDs), yet the in vivo roles of phase separation remain poorly understood. TIA proteins contain a C-terminal PrLD, and mutations in the PrLD are associated with several diseases. Here, we show that the C. elegans TIAR-2/TIA protein functions cell autonomously to inhibit axon regeneration. TIAR-2 undergoes liquid-liquid phase separation in vitro and forms granules with liquid-like properties in vivo. Axon injury induces a transient increase in TIAR-2 granule number. The PrLD is necessary and sufficient for granule formation and inhibiting regeneration. Tyrosine residues within the PrLD are important for granule formation and inhibition of regeneration. TIAR-2 is also serine phosphorylated in vivo. Non-phosphorylatable TIAR-2 variants do not form granules and are unable to inhibit axon regeneration. Our data demonstrate an in vivo function for phase-separated TIAR-2 and identify features critical for its function in axon regeneration.
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Affiliation(s)
- Matthew G Andrusiak
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Panid Sharifnia
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Xiaohui Lyu
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Zhiping Wang
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Andrea M Dickey
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Zilu Wu
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Andrew D Chisholm
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Yishi Jin
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
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10
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Sakai Y, Hanafusa H, Pastuhov SI, Shimizu T, Li C, Hisamoto N, Matsumoto K. TDP2 negatively regulates axon regeneration by inducing SUMOylation of an Ets transcription factor. EMBO Rep 2019; 20:e47517. [PMID: 31393064 PMCID: PMC6776894 DOI: 10.15252/embr.201847517] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 07/03/2019] [Accepted: 07/15/2019] [Indexed: 12/02/2022] Open
Abstract
In Caenorhabditis elegans, the JNK MAP kinase (MAPK) pathway is important for axon regeneration. The JNK pathway is activated by a signaling cascade consisting of the growth factor SVH-1 and its receptor tyrosine kinase SVH-2. Expression of the svh-2 gene is induced by axonal injury in a process involving the transcription factors ETS-4 and CEBP-1. Here, we find that svh-14/mxl-1, a gene encoding a Max-like transcription factor, is required for activation of svh-2 expression in response to axonal injury. We show that MXL-1 binds to and inhibits the function of TDPT-1, a C. elegans homolog of mammalian tyrosyl-DNA phosphodiesterase 2 [TDP2; also called Ets1-associated protein II (EAPII)]. Deletion of tdpt-1 suppresses the mxl-1 defect, but not the ets-4 defect, in axon regeneration. TDPT-1 induces SUMOylation of ETS-4, which inhibits ETS-4 transcriptional activity, and MXL-1 counteracts this effect. Thus, TDPT-1 interacts with two different transcription factors in axon regeneration.
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Affiliation(s)
- Yoshiki Sakai
- Division of Biological ScienceGraduate School of ScienceNagoya UniversityNagoyaJapan
| | - Hiroshi Hanafusa
- Division of Biological ScienceGraduate School of ScienceNagoya UniversityNagoyaJapan
| | - Strahil Iv Pastuhov
- Division of Biological ScienceGraduate School of ScienceNagoya UniversityNagoyaJapan
| | - Tatsuhiro Shimizu
- Division of Biological ScienceGraduate School of ScienceNagoya UniversityNagoyaJapan
| | - Chun Li
- Division of Biological ScienceGraduate School of ScienceNagoya UniversityNagoyaJapan
| | - Naoki Hisamoto
- Division of Biological ScienceGraduate School of ScienceNagoya UniversityNagoyaJapan
| | - Kunihiro Matsumoto
- Division of Biological ScienceGraduate School of ScienceNagoya UniversityNagoyaJapan
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11
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Shimizu T, Kato Y, Sakai Y, Hisamoto N, Matsumoto K. N-Glycosylation of the Discoidin Domain Receptor Is Required for Axon Regeneration in Caenorhabditis elegans. Genetics 2019; 213:491-500. [PMID: 31371405 PMCID: PMC6781908 DOI: 10.1534/genetics.119.302492] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 07/25/2019] [Indexed: 01/17/2023] Open
Abstract
Axon regeneration following neuronal injury is an important repair mechanism that is not well understood at present. In Caenorhabditis elegans, axon regeneration is regulated by DDR-2, a receptor tyrosine kinase (RTK) that contains a discoidin domain and modulates the Met-like SVH-2 RTK-JNK MAP kinase signaling pathway. Here, we describe the svh-10/sqv-3 and svh-11 genes, which encode components of a conserved glycosylation pathway, and show that they modulate axon regeneration in C. elegans Overexpression of svh-2, but not of ddr-2, can suppress the axon regeneration defect observed in svh-11 mutants, suggesting that SVH-11 functions between DDR-2 and SVH-2 in this glycosylation pathway. Furthermore, we found that DDR-2 is N-glycosylated at the Asn-141 residue located in its discoidin domain, and mutation of this residue caused an axon regeneration defect. These findings indicate that N-linked glycosylation plays an important role in axon regeneration in C. elegans.
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Affiliation(s)
- Tatsuhiro Shimizu
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, 464-8602, Japan
| | - Yuka Kato
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, 464-8602, Japan
| | - Yoshiki Sakai
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, 464-8602, Japan
| | - Naoki Hisamoto
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, 464-8602, Japan
| | - Kunihiro Matsumoto
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, 464-8602, Japan
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12
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Malinow RA, Ying P, Koorman T, Boxem M, Jin Y, Kim KW. Functional Dissection of C. elegans bZip-Protein CEBP-1 Reveals Novel Structural Motifs Required for Axon Regeneration and Nuclear Import. Front Cell Neurosci 2019; 13:348. [PMID: 31417366 PMCID: PMC6685058 DOI: 10.3389/fncel.2019.00348] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/15/2019] [Indexed: 12/02/2022] Open
Abstract
The basic leucine-zipper (bZIP) domain transcription factors CCAAT/enhancer-binding proteins (C/EBP) have a variety of roles in cell proliferation, differentiation, and stress response. In the nervous system, several isoforms of C/EBP function in learning and memory, neuronal plasticity, neuroinflammation, and axon regeneration. We previously reported that the Caenorhabditis elegans C/EBP homolog, CEBP-1, is essential for axon regeneration. CEBP-1 consists of 319 amino acids, with its bZIP domain at the C-terminus and a long N-terminal fragment with no known protein motifs. Here, using forward genetic screening with targeted genome editing, we have identified a unique domain in the N-terminus that is critical for its in vivo function. Additionally, we characterized three nuclear localization signals (NLS) in CEBP-1 that act together to mediate CEBP-1’s nuclear import. Moreover, the Importin-α, IMA-3, can bind to CEBP-1 via one of the NLS. ima-3 is ubiquitously expressed in all somatic cells, and ima-3 null mutants are larval lethal. Using Cre-lox dependent neuron-specific deletion strategy, we show that ima-3 is not critical for axon development, but is required for axon regeneration in adults. Together, these data advance our understanding of CEBP-1’s function, and suggest new regulators that remain to be identified to expand the CEBP-1 protein interactome.
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Affiliation(s)
- Rose Aria Malinow
- Section of Neurobiology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Phoenix Ying
- Section of Neurobiology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Thijs Koorman
- Department of Biology, Utrecht University, Utrecht, Netherlands
| | - Mike Boxem
- Department of Biology, Utrecht University, Utrecht, Netherlands
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Kyung Won Kim
- Convergence Program of Material Science for Medicine and Pharmaceutics, Department of Life Science, Multidisciplinary Genome Institute, Hallym University, Chuncheon, South Korea
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13
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Hilton BJ, Blanquie O, Tedeschi A, Bradke F. High-resolution 3D imaging and analysis of axon regeneration in unsectioned spinal cord with or without tissue clearing. Nat Protoc 2019; 14:1235-1260. [DOI: 10.1038/s41596-019-0140-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 01/17/2019] [Indexed: 12/12/2022]
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14
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Disruption of RAB-5 Increases EFF-1 Fusogen Availability at the Cell Surface and Promotes the Regenerative Axonal Fusion Capacity of the Neuron. J Neurosci 2019; 39:2823-2836. [PMID: 30737314 DOI: 10.1523/jneurosci.1952-18.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 01/28/2019] [Accepted: 01/29/2019] [Indexed: 12/29/2022] Open
Abstract
Following a transection injury to the axon, neurons from a number of species have the ability to undergo spontaneous repair via fusion of the two separated axonal fragments. In the nematode Caenorhabditis elegans, this highly efficient regenerative axonal fusion is mediated by epithelial fusion failure-1 (EFF-1), a fusogenic protein that functions at the membrane to merge the two axonal fragments. Identifying modulators of axonal fusion and EFF-1 is an important step toward a better understanding of this repair process. Here, we present evidence that the small GTPase RAB-5 acts to inhibit axonal fusion, a function achieved via endocytosis of EFF-1 within the injured neuron. Therefore, we find that perturbing RAB-5 activity is sufficient to restore axonal fusion in mutant animals with decreased axonal fusion capacity. This is accompanied by enhanced membranous localization of EFF-1 and the production of extracellular EFF-1-containing vesicles. These findings identify RAB-5 as a novel regulator of axonal fusion in C. elegans hermaphrodites and the first regulator of EFF-1 in neurons.SIGNIFICANCE STATEMENT Peripheral and central nerve injuries cause life-long disabilities due to the fact that repair rarely leads to reinnervation of the target tissue. In the nematode Caenorhabditis elegans, axonal regeneration can proceed through axonal fusion, whereby a regrowing axon reconnects and fuses with its own separated distal fragment, restoring the original axonal tract. We have characterized axonal fusion and established that the fusogen epithelial fusion failure-1 (EFF-1) is a key element for fusing the two separated axonal fragments back together. Here, we show that the small GTPase RAB-5 is a key cell-intrinsic regulator of the fusogen EFF-1 and can in turn regulate axonal fusion. Our findings expand the possibility for this process to be controlled and exploited to facilitate axonal repair in medical applications.
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Neumann B, Linton C, Giordano-Santini R, Hilliard MA. Axonal fusion: An alternative and efficient mechanism of nerve repair. Prog Neurobiol 2018; 173:88-101. [PMID: 30500382 DOI: 10.1016/j.pneurobio.2018.11.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/22/2018] [Accepted: 11/26/2018] [Indexed: 02/07/2023]
Abstract
Injuries to the nervous system can cause lifelong morbidity due to the disconnect that occurs between nerve cells and their cellular targets. Re-establishing these lost connections is the ultimate goal of endogenous regenerative mechanisms, as well as those induced by exogenous manipulations in a laboratory or clinical setting. Reconnection between severed neuronal fibers occurs spontaneously in some invertebrate species and can be induced in mammalian systems. This process, known as axonal fusion, represents a highly efficient means of repair after injury. Recent progress has greatly enhanced our understanding of the molecular control of axonal fusion, demonstrating that the machinery required for the engulfment of apoptotic cells is repurposed to mediate the reconnection between severed axon fragments, which are subsequently merged by fusogen proteins. Here, we review our current understanding of naturally occurring axonal fusion events, as well as those being ectopically produced with the aim of achieving better clinical outcomes.
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Affiliation(s)
- Brent Neumann
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne VIC 3800, Australia.
| | - Casey Linton
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Rosina Giordano-Santini
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Massimo A Hilliard
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
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16
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Ding C, Hammarlund M. Aberrant information transfer interferes with functional axon regeneration. eLife 2018; 7:e38829. [PMID: 30371349 PMCID: PMC6231761 DOI: 10.7554/elife.38829] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 10/26/2018] [Indexed: 12/16/2022] Open
Abstract
Functional axon regeneration requires regenerating neurons to restore appropriate synaptic connectivity and circuit function. To model this process, we developed an assay in Caenorhabditis elegans that links axon and synapse regeneration of a single neuron to recovery of behavior. After axon injury and regeneration of the DA9 neuron, synapses reform at their pre-injury location. However, these regenerated synapses often lack key molecular components. Further, synaptic vesicles accumulate in the dendrite in response to axon injury. Dendritic vesicle release results in information misrouting that suppresses behavioral recovery. Dendritic synapse formation depends on dynein and jnk-1. But even when information transfer is corrected, axonal synapses fail to adequately transmit information. Our study reveals unexpected plasticity during functional regeneration. Regeneration of the axon is not sufficient for the reformation of correct neuronal circuits after injury. Rather, synapse reformation and function are also key variables, and manipulation of circuit reformation improves behavioral recovery.
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Affiliation(s)
- Chen Ding
- Department of NeuroscienceYale UniversityNew HavenUnited States
| | - Marc Hammarlund
- Department of NeuroscienceYale UniversityNew HavenUnited States
- Department of GeneticsYale UniversityNew HavenUnited States
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17
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Phosphatidylserine exposure mediated by ABC transporter activates the integrin signaling pathway promoting axon regeneration. Nat Commun 2018; 9:3099. [PMID: 30082731 PMCID: PMC6079064 DOI: 10.1038/s41467-018-05478-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 07/02/2018] [Indexed: 12/22/2022] Open
Abstract
Following axon injury, a cascade of signaling events is triggered to initiate axon regeneration. However, the mechanisms regulating axon regeneration are not well understood at present. In Caenorhabditis elegans, axon regeneration utilizes many of the components involved in phagocytosis, including integrin and Rac GTPase. Here, we identify the transthyretin (TTR)-like protein TTR-11 as a component functioning in axon regeneration upstream of integrin. We show that TTR-11 binds to both the extracellular domain of integrin-α and phosphatidylserine (PS). Axon injury induces the accumulation of PS around the injured axons in a manner dependent on TTR-11, the ABC transporter CED-7, and the caspase CED-3. Furthermore, we demonstrate that CED-3 activates CED-7 during axon regeneration. Thus, TTR-11 functions to link the PS injury signal to activation of the integrin pathway, which then initiates axon regeneration.
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18
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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: 22] [Impact Index Per Article: 3.7] [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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19
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Basu A, Dey S, Puri D, Das Saha N, Sabharwal V, Thyagarajan P, Srivastava P, Koushika SP, Ghosh-Roy A. let-7 miRNA controls CED-7 homotypic adhesion and EFF-1-mediated axonal self-fusion to restore touch sensation following injury. Proc Natl Acad Sci U S A 2017; 114:E10206-E10215. [PMID: 29109254 PMCID: PMC5703274 DOI: 10.1073/pnas.1704372114] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neuronal injury often leads to devastating consequences such as loss of senses or locomotion. Restoration of function after injury relies on whether the injured axons can find their target cells. Although fusion between injured proximal axon and distal fragment has been observed in many organisms, its functional significance is not clear. Here, using Caenorhabditis elegans mechanosensory neurons, we address this question. Using two femtosecond lasers simultaneously, we could scan and sever posterior lateral microtubule neurons [posterior lateral microtubules (PLMs)] on both sides of the worm. We showed that axotomy of both PLMs leads to a dramatic loss of posterior touch sensation. During the regenerative phase, only axons that fuse to their distal counterparts contribute to functional recovery. Loss of let-7 miRNA promotes functional restoration in both larval and adult stages. In the L4 stage, loss of let-7 increases fusion events by increasing the mRNA level of one of the cell-recognition molecules, CED-7. The ability to establish cytoplasmic continuity between the proximal and distal ends declines with age. Loss of let-7 overcomes this barrier by promoting axonal transport and enrichment of the EFF-1 fusogen at the growing tip of cut processes. Our data reveal the functional property of a regenerating neuron.
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Affiliation(s)
- Atrayee Basu
- National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | - Shirshendu Dey
- Bruker India Scientific Private Ltd, New Delhi 110019, India
| | - Dharmendra Puri
- National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | - Nilanjana Das Saha
- National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | - Vidur Sabharwal
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai 400 005, India
| | - Pankajam Thyagarajan
- National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | - Prerna Srivastava
- National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | | | - Anindya Ghosh-Roy
- National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India;
- Wellcome Trust-Department of Biotechnology India Alliance, Banjara Hills, Hyderabad, Telangana 500034, India
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20
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Abstract
Although much is known about the regenerative capacity of retinal ganglion cells, very significant barriers remain in our ability to restore visual function following traumatic injury or disease-induced degeneration. Here we summarize our current understanding of the factors regulating axon guidance and target engagement in regenerating axons, and review the state of the field of neural regeneration, focusing on the visual system and highlighting studies using other model systems that can inform analysis of visual system regeneration. This overview is motivated by a Society for Neuroscience Satellite meeting, "Reconnecting Neurons in the Visual System," held in October 2015 sponsored by the National Eye Institute as part of their "Audacious Goals Initiative" and co-organized by Carol Mason (Columbia University) and Michael Crair (Yale University). The collective wisdom of the conference participants pointed to important gaps in our knowledge and barriers to progress in promoting the restoration of visual system function. This article is thus a summary of our existing understanding of visual system regeneration and provides a blueprint for future progress in the field.
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21
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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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22
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Weng YL, An R, Cassin J, Joseph J, Mi R, Wang C, Zhong C, Jin SG, Pfeifer GP, Bellacosa A, Dong X, Hoke A, He Z, Song H, Ming GL. An Intrinsic Epigenetic Barrier for Functional Axon Regeneration. Neuron 2017; 94:337-346.e6. [PMID: 28426967 PMCID: PMC6007997 DOI: 10.1016/j.neuron.2017.03.034] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 02/05/2017] [Accepted: 03/23/2017] [Indexed: 12/15/2022]
Abstract
Mature neurons in the adult peripheral nervous system can effectively switch from a dormant state with little axonal growth to robust axon regeneration upon injury. The mechanisms by which injury unlocks mature neurons' intrinsic axonal growth competence are not well understood. Here, we show that peripheral sciatic nerve lesion in adult mice leads to elevated levels of Tet3 and 5-hydroxylmethylcytosine in dorsal root ganglion (DRG) neurons. Functionally, Tet3 is required for robust axon regeneration of DRG neurons and behavioral recovery. Mechanistically, peripheral nerve injury induces DNA demethylation and upregulation of multiple regeneration-associated genes in a Tet3- and thymine DNA glycosylase-dependent fashion in DRG neurons. In addition, Pten deletion-induced axon regeneration of retinal ganglion neurons in the adult CNS is attenuated upon Tet1 knockdown. Together, our study suggests an epigenetic barrier that can be removed by active DNA demethylation to permit axon regeneration in the adult mammalian nervous system.
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Affiliation(s)
- Yi-Lan Weng
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ran An
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200040, China
| | - Jessica Cassin
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Pre-doctoral Human Genetics Training Program, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jessica Joseph
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ruifa Mi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Chen Wang
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, and Department of Neurology, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Chun Zhong
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Seung-Gi Jin
- Center for Epigenetics, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Gerd P. Pfeifer
- Center for Epigenetics, Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Alfonso Bellacosa
- Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ahmet Hoke
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Zhigang He
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, and Department of Neurology, 300 Longwood Avenue, Boston, MA 02115, USA
| | - Hongjun Song
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Pre-doctoral Human Genetics Training Program, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neuroscience, Mahoney Institute for Neurosciences, Perelman School for Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Guo-li Ming
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neuroscience, Mahoney Institute for Neurosciences, Perelman School for Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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23
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Superoxide dismutase SOD-1 modulates C. elegans pathogen avoidance behavior. Sci Rep 2017; 7:45128. [PMID: 28322326 PMCID: PMC5359715 DOI: 10.1038/srep45128] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 02/16/2017] [Indexed: 12/26/2022] Open
Abstract
The C. elegans nervous system mediates protective physiological and behavioral responses amid infection. However, it remains largely unknown how the nervous system responds to reactive oxygen species (ROS) activated by pathogenic microbes during infection. Here, we show superoxide dismutase-1 (SOD-1), an enzyme that converts superoxide into less toxic hydrogen peroxide and oxygen, functions in the gustatory neuron ASER to mediate C. elegans pathogen avoidance response. When C. elegans first encounters pathogenic bacteria P. aeruginosa, SOD-1 is induced in the ASER neuron. After prolonged P. aeruginosa exposure, ASER-specific SOD-1 expression is diminished. In turn, C. elegans starts to vacate the pathogenic bacteria lawn. Genetic knockdown experiments reveal that pathogen-induced ROS activate sod-1 dependent behavioral response non cell-autonomously. We postulate that the delayed aversive response to detrimental microbes may provide survival benefits by allowing C. elegans to temporarily utilize food that is tainted with pathogens as an additional energy source. Our data offer a mechanistic insight into how the nervous system mediates food-seeking behavior amid oxidative stress and suggest that the internal state of redox homeostasis could underlie the behavioral response to harmful microbial species.
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24
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Kravtsov V, Oren-Suissa M, Podbilewicz B. AFF-1 fusogen can rejuvenate the regenerative potential of adult dendritic trees via self-fusion. Development 2017; 144:2364-2374. [DOI: 10.1242/dev.150037] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 05/27/2017] [Indexed: 12/20/2022]
Abstract
The aging brain undergoes structural changes, affecting brain homeostasis, neuronal function and consequently cognition. The complex architecture of dendritic arbors poses a challenge to understanding age-dependent morphological alterations, behavioral plasticity and remodeling following brain injury. Here, we use the PVD polymodal neurons of C. elegans as a model to study how aging affects neuronal plasticity. Using confocal live imaging of C. elegans PVD neurons, we demonstrate age-related progressive morphological alterations of intricate dendritic arbors. We show that insulin/IGF-1 receptor mutations (daf-2) fail to inhibit the progressive morphological aging of dendrites and do not prevent the minor decline in response to harsh touch during aging. We uncovered that PVD aging is characterized by a major decline in regenerative potential of dendrites following experimental laser dendrotomy. Furthermore, the remodeling of transected dendritic trees via AFF-1-mediated self-fusion can be restored in old animals by DAF-2 insulin/IGF-1 receptor mutations, and can be differentially reestablished by ectopic expression of AFF-1 fusion protein (fusogen). Thus, AFF-1 fusogen ectopically expressed in the PVD and mutations in DAF-2/IGF-1R, differentially rejuvenate some aspects of dendritic regeneration following injury.
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Affiliation(s)
- Veronika Kravtsov
- Department of Biology, Technion- Israel Institute of Technology, Haifa 32000, Israel
| | - Meital Oren-Suissa
- 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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25
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Miranda-Vizuete A, Veal EA. Caenorhabditis elegans as a model for understanding ROS function in physiology and disease. Redox Biol 2016; 11:708-714. [PMID: 28193593 PMCID: PMC5304259 DOI: 10.1016/j.redox.2016.12.020] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 12/19/2016] [Indexed: 01/05/2023] Open
Abstract
ROS (reactive oxygen species) are potentially damaging by-products of aerobic metabolism which, unchecked, can have detrimental effects on cell function. However, it is now widely accepted that, at physiological levels, certain ROS play important roles in cell signaling, acting as second messengers to regulate cell choices that contribute to the development, adaptation and survival of plants and animals. Despite important recent advances in the biochemical tools available to study redox-signaling, the molecular mechanisms underlying most of these responses remain poorly understood, particularly in multicellular organisms. As we will review here, C. elegans has emerged as a powerful animal model to elucidate these and other aspects of redox biology.
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Affiliation(s)
- Antonio Miranda-Vizuete
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, 41013 Sevilla, Spain.
| | - Elizabeth A Veal
- Institute for Cell and Molecular Biosciences, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK; Institute for Ageing, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
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26
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Cartoni R, Norsworthy MW, Bei F, Wang C, Li S, Zhang Y, Gabel CV, Schwarz TL, He Z. The Mammalian-Specific Protein Armcx1 Regulates Mitochondrial Transport during Axon Regeneration. Neuron 2016; 92:1294-1307. [PMID: 28009275 PMCID: PMC5189716 DOI: 10.1016/j.neuron.2016.10.060] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 08/14/2016] [Accepted: 10/20/2016] [Indexed: 11/29/2022]
Abstract
Mitochondrial transport is crucial for neuronal and axonal physiology. However, whether and how it impacts neuronal injury responses, such as neuronal survival and axon regeneration, remain largely unknown. In an established mouse model with robust axon regeneration, we show that Armcx1, a mammalian-specific gene encoding a mitochondria-localized protein, is upregulated after axotomy in this high regeneration condition. Armcx1 overexpression enhances mitochondrial transport in adult retinal ganglion cells (RGCs). Importantly, Armcx1 also promotes both neuronal survival and axon regeneration after injury, and these effects depend on its mitochondrial localization. Furthermore, Armcx1 knockdown undermines both neuronal survival and axon regeneration in the high regenerative capacity model, further supporting a key role of Armcx1 in regulating neuronal injury responses in the adult central nervous system (CNS). Our findings suggest that Armcx1 controls mitochondrial transport during neuronal repair.
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Affiliation(s)
- Romain Cartoni
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA.
| | - Michael W Norsworthy
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Fengfeng Bei
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Chen Wang
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Siwei Li
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Yiling Zhang
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Christopher V Gabel
- Department of Physiology and Biophysics, Photonics Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Thomas L Schwarz
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
| | - Zhigang He
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA.
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27
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Kalichamy SS, Lee TY, Yoon KH, Lee JI. Hypergravity hinders axonal development of motor neurons in Caenorhabditis elegans. PeerJ 2016; 4:e2666. [PMID: 27833821 PMCID: PMC5101602 DOI: 10.7717/peerj.2666] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 10/08/2016] [Indexed: 12/29/2022] Open
Abstract
As space flight becomes more accessible in the future, humans will be exposed to gravity conditions other than our 1G environment on Earth. Our bodies and physiology, however, are adapted for life at 1G gravity. Altering gravity can have profound effects on the body, particularly the development of muscles, but the reasons and biology behind gravity’s effect are not fully known. We asked whether increasing gravity had effects on the development of motor neurons that innervate and control muscle, a relatively unexplored area of gravity biology. Using the nematode model organism Caenorhabditis elegans, we examined changes in response to hypergravity in the development of the 19 GABAergic DD/VD motor neurons that innervate body muscle. We found that a high gravity force above 10G significantly increases the number of animals with defects in the development of axonal projections from the DD/VD neurons. We showed that a critical period of hypergravity exposure during the embryonic/early larval stage was sufficient to induce defects. While characterizing the nature of the axonal defects, we found that in normal 1G gravity conditions, DD/VD axonal defects occasionally occurred, with the majority of defects occurring on the dorsal side of the animal and in the mid-body region, and a significantly higher rate of error in the 13 VD axons than the 6 DD axons. Hypergravity exposure increased the rate of DD/VD axonal defects, but did not change the distribution or the characteristics of the defects. Our study demonstrates that altering gravity can impact motor neuron development.
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Affiliation(s)
| | - Tong Young Lee
- Division of Biological Science and Technology, Yonsei University , Wonju , South Korea
| | - Kyoung-Hye Yoon
- Division of Biological Science and Technology, Yonsei University , Wonju , South Korea
| | - Jin Il Lee
- Division of Biological Science and Technology, Yonsei University , Wonju , South Korea
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28
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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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29
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Luo X, Ribeiro M, Bray ER, Lee DH, Yungher BJ, Mehta ST, Thakor KA, Diaz F, Lee JK, Moraes CT, Bixby JL, Lemmon VP, Park KK. Enhanced Transcriptional Activity and Mitochondrial Localization of STAT3 Co-induce Axon Regrowth in the Adult Central Nervous System. Cell Rep 2016; 15:398-410. [PMID: 27050520 DOI: 10.1016/j.celrep.2016.03.029] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 12/21/2015] [Accepted: 03/07/2016] [Indexed: 11/26/2022] Open
Abstract
Signal transducer and activator of transcription 3 (STAT3) is a transcription factor central to axon regrowth with an enigmatic ability to act in different subcellular regions independently of its transcriptional roles. However, its roles in mature CNS neurons remain unclear. Here, we show that along with nuclear translocation, STAT3 translocates to mitochondria in mature CNS neurons upon cytokine stimulation. Loss- and gain-of-function studies using knockout mice and viral expression of various STAT3 mutants demonstrate that STAT3's transcriptional function is indispensable for CNS axon regrowth, whereas mitochondrial STAT3 enhances bioenergetics and further potentiates regrowth. STAT3's localization, functions, and growth-promoting effects are regulated by mitogen-activated protein kinase kinase (MEK), an effect further enhanced by Pten deletion, leading to extensive axon regrowth in the mouse optic pathway and spinal cord. These results highlight CNS neuronal dependence on STAT3 transcriptional activity, with mitochondrial STAT3 providing ancillary roles, and illustrate a critical contribution for MEK in enhancing diverse STAT3 functions and axon regrowth.
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Affiliation(s)
- Xueting Luo
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Marcio Ribeiro
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Eric R Bray
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Do-Hun Lee
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Benjamin J Yungher
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Saloni T Mehta
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Kinjal A Thakor
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Francisca Diaz
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Jae K Lee
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Carlos T Moraes
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - John L Bixby
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Vance P Lemmon
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Kevin K Park
- Department of Neurological Surgery, Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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30
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Alam T, Maruyama H, Li C, Pastuhov SI, Nix P, Bastiani M, Hisamoto N, Matsumoto K. Axotomy-induced HIF-serotonin signalling axis promotes axon regeneration in C. elegans. Nat Commun 2016; 7:10388. [PMID: 26790951 PMCID: PMC4735912 DOI: 10.1038/ncomms10388] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 12/05/2015] [Indexed: 12/28/2022] Open
Abstract
The molecular mechanisms underlying the ability of axons to regenerate after injury remain poorly understood. Here we show that in Caenorhabditis elegans, axotomy induces ectopic expression of serotonin (5-HT) in axotomized non-serotonergic neurons via HIF-1, a hypoxia-inducible transcription factor, and that 5-HT subsequently promotes axon regeneration by autocrine signalling through the SER-7 5-HT receptor. Furthermore, we identify the rhgf-1 and rga-5 genes, encoding homologues of RhoGEF and RhoGAP, respectively, as regulators of axon regeneration. We demonstrate that one pathway initiated by SER-7 acts upstream of the C. elegans RhoA homolog RHO-1 in neuron regeneration, which functions via G12α and RHGF-1. In this pathway, RHO-1 inhibits diacylglycerol kinase, resulting in an increase in diacylglycerol. SER-7 also promotes axon regeneration by activating the cyclic AMP (cAMP) signalling pathway. Thus, HIF-1-mediated activation of 5-HT signalling promotes axon regeneration by activating both the RhoA and cAMP pathways.
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Affiliation(s)
- Tanimul Alam
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Hiroki Maruyama
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Chun Li
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Strahil Iv. Pastuhov
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Paola Nix
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, Utah 84112-0840, USA
| | - Michael Bastiani
- Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, Utah 84112-0840, USA
| | - Naoki Hisamoto
- 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
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31
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Meng L, Mulcahy B, Cook SJ, Neubauer M, Wan A, Jin Y, Yan D. The Cell Death Pathway Regulates Synapse Elimination through Cleavage of Gelsolin in Caenorhabditis elegans Neurons. Cell Rep 2015; 11:1737-48. [PMID: 26074078 DOI: 10.1016/j.celrep.2015.05.031] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 05/01/2015] [Accepted: 05/15/2015] [Indexed: 11/17/2022] Open
Abstract
Synapse elimination occurs in development, plasticity, and disease. Although the importance of synapse elimination has been documented in many studies, the molecular mechanisms underlying this process are unclear. Here, using the development of C. elegans RME neurons as a model, we have uncovered a function for the apoptosis pathway in synapse elimination. We find that the conserved apoptotic cell death (CED) pathway and axonal mitochondria are required for the elimination of transiently formed clusters of presynaptic components in RME neurons. This function of the CED pathway involves the activation of the actin-filament-severing protein, GSNL-1. Furthermore, we show that caspase CED-3 cleaves GSNL-1 at a conserved C-terminal region and that the cleaved active form of GSNL-1 promotes its actin-severing ability. Our data suggest that activation of the CED pathway contributes to selective elimination of synapses through disassembly of the actin filament network.
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Affiliation(s)
- Lingfeng Meng
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Research Drive, Durham, NC 27710, USA
| | - Ben Mulcahy
- Lunenfeld-Tanenbaum Research Institute, Toronto, ON M5G 1X5, Canada
| | - Steven J Cook
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Marianna Neubauer
- Department of Physics and Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Airong Wan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Research Drive, Durham, NC 27710, USA
| | - Yishi Jin
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Dong Yan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Research Drive, Durham, NC 27710, USA; Department of Neurobiology and Duke Institute for Brain Sciences, Duke University Medical Center, Research Drive, Durham, NC 27710, USA.
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32
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Abstract
A little over 50 years ago, Sydney Brenner had the foresight to develop the nematode (round worm) Caenorhabditis elegans as a genetic model for understanding questions of developmental biology and neurobiology. Over time, research on C. elegans has expanded to explore a wealth of diverse areas in modern biology including studies of the basic functions and interactions of eukaryotic cells, host-parasite interactions, and evolution. C. elegans has also become an important organism in which to study processes that go awry in human diseases. This primer introduces the organism and the many features that make it an outstanding experimental system, including its small size, rapid life cycle, transparency, and well-annotated genome. We survey the basic anatomical features, common technical approaches, and important discoveries in C. elegans research. Key to studying C. elegans has been the ability to address biological problems genetically, using both forward and reverse genetics, both at the level of the entire organism and at the level of the single, identified cell. These possibilities make C. elegans useful not only in research laboratories, but also in the classroom where it can be used to excite students who actually can see what is happening inside live cells and tissues.
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Affiliation(s)
- Ann K Corsi
- Biology Department, The Catholic University of America, Washington, DC 20064
| | - Bruce Wightman
- Biology Department, Muhlenberg College, Allentown, Pennsylvania 18104
| | - Martin Chalfie
- Department of Biological Sciences, Columbia University, New York, New York 10027
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33
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Kim KW, Jin Y. Neuronal responses to stress and injury in C. elegans. FEBS Lett 2015; 589:1644-52. [PMID: 25979176 DOI: 10.1016/j.febslet.2015.05.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Revised: 04/30/2015] [Accepted: 05/04/2015] [Indexed: 12/22/2022]
Abstract
The nervous system plays critical roles in the stress response. Animals can survive and function under harsh conditions, and resist and recover from injuries because neurons perceive and respond to various stressors through specific regulatory mechanisms. Caenorhabditis elegans has served as an excellent model to discover fundamental mechanisms underlying the neuronal response to stress. The basic physiological processes that C. elegans exhibits under stress conditions are similar to those observed in higher organisms. Many molecular pathways activated by environmental and cellular stresses are also conserved. In this review, we summarize major findings in examining neuronal responses to hypoxia, oxidative stress, osmotic stress, and traumatic injury. These studies from C. elegans have provided novel insights into our understanding of neuronal responses to stress at the molecular, cellular, and circuit levels.
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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, United States.
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, United States; Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA 92093, United States.
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34
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Chuang M, Goncharov A, Wang S, Oegema K, Jin Y, Chisholm AD. The microtubule minus-end-binding protein patronin/PTRN-1 is required for axon regeneration in C. elegans. Cell Rep 2014; 9:874-83. [PMID: 25437544 DOI: 10.1016/j.celrep.2014.09.054] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Revised: 09/15/2014] [Accepted: 09/29/2014] [Indexed: 11/17/2022] Open
Abstract
Precise regulation of microtubule (MT) dynamics is increasingly recognized as a critical determinant of axon regeneration. In contrast to developing neurons, mature axons exhibit noncentrosomal microtubule nucleation. The factors regulating noncentrosomal MT architecture in axon regeneration remain poorly understood. We report that PTRN-1, the C. elegans member of the Patronin/Nezha/calmodulin- and spectrin-associated protein (CAMSAP) family of microtubule minus-end-binding proteins, is critical for efficient axon regeneration in vivo. ptrn-1-null mutants display generally normal developmental axon outgrowth but significantly impaired regenerative regrowth after laser axotomy. Unexpectedly, mature axons in ptrn-1 mutants display elevated numbers of dynamic axonal MTs before and after injury, suggesting that PTRN-1 inhibits MT dynamics. The CKK domain of PTRN-1 is necessary and sufficient for its functions in axon regeneration and MT dynamics and appears to stabilize MTs independent of minus-end localization. Whereas in developing neurons, PTRN-1 inhibits activity of the DLK-1 mitogen-activated protein kinase (MAPK) cascade, we find that, in regeneration, PTRN-1 and DLK-1 function together to promote axonal regrowth.
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Affiliation(s)
- Marian Chuang
- Section of Neurobiology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Alexandr Goncharov
- Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA
| | - Shaohe Wang
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093, USA; Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Karen Oegema
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093, USA
| | - 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; 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.
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