1
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Juanez K, Ghose P. Repurposing the Killing Machine: Non-canonical Roles of the Cell Death Apparatus in Caenorhabditis elegans Neurons. Front Cell Dev Biol 2022; 10:825124. [PMID: 35237604 PMCID: PMC8882910 DOI: 10.3389/fcell.2022.825124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/31/2022] [Indexed: 12/29/2022] Open
Abstract
Here we highlight the increasingly divergent functions of the Caenorhabditis elegans cell elimination genes in the nervous system, beyond their well-documented roles in cell dismantling and removal. We describe relevant background on the C. elegans nervous system together with the apoptotic cell death and engulfment pathways, highlighting pioneering work in C. elegans. We discuss in detail the unexpected, atypical roles of cell elimination genes in various aspects of neuronal development, response and function. This includes the regulation of cell division, pruning, axon regeneration, and behavioral outputs. We share our outlook on expanding our thinking as to what cell elimination genes can do and noting their versatility. We speculate on the existence of novel genes downstream and upstream of the canonical cell death pathways relevant to neuronal biology. We also propose future directions emphasizing the exploration of the roles of cell death genes in pruning and guidance during embryonic development.
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2
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Kulkarni SS, Sabharwal V, Sheoran S, Basu A, Matsumoto K, Hisamoto N, Ghosh-Roy A, Koushika SP. UNC-16 alters DLK-1 localization and negatively regulates actin and microtubule dynamics in Caenorhabditis elegans regenerating neurons. Genetics 2021; 219:6359182. [PMID: 34740241 DOI: 10.1093/genetics/iyab139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 08/13/2021] [Indexed: 11/13/2022] Open
Abstract
Neuronal regeneration after injury depends on the intrinsic growth potential of neurons. Our study shows that UNC-16, a Caenorhabditis elegans JIP3 homolog, inhibits axonal regeneration by regulating initiation and rate of regrowth. This occurs through the inhibition of the regeneration-promoting activity of the long isoform of DLK-1 and independently of the inhibitory short isoform of DLK-1. We show that UNC-16 promotes DLK-1 punctate localization in a concentration-dependent manner limiting the availability of the long isoform of DLK-1 at the cut site, minutes after injury. UNC-16 negatively regulates actin dynamics through DLK-1 and microtubule dynamics partially via DLK-1. We show that post-injury cytoskeletal dynamics in unc-16 mutants are also partially dependent on CEBP-1. The faster regeneration seen in unc-16 mutants does not lead to functional recovery. Our data suggest that the inhibitory control by UNC-16 and the short isoform of DLK-1 balances the intrinsic growth-promoting function of the long isoform of DLK-1 in vivo. We propose a model where UNC-16's inhibitory role in regeneration occurs through both a tight temporal and spatial control of DLK-1 and cytoskeletal dynamics.
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Affiliation(s)
- Sucheta S Kulkarni
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, 560065, India
| | - Vidur Sabharwal
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra 400005, India
| | - Seema Sheoran
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, 560065, India
| | - Atrayee Basu
- Department of Biotechnology National Brain Research Centre, Manesar 122052, India
| | - Kunihiro Matsumoto
- Department of Molecular Biology, Nagoya University, Nagoya 4648601, Japan
| | - Naoki Hisamoto
- Department of Molecular Biology, Nagoya University, Nagoya 4648601, Japan
| | - Anindya Ghosh-Roy
- Department of Biotechnology National Brain Research Centre, Manesar 122052, India
| | - Sandhya P Koushika
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra 400005, India
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3
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Badhiwala KN, Primack AS, Juliano CE, Robinson JT. Multiple neuronal networks coordinate Hydra mechanosensory behavior. eLife 2021; 10:e64108. [PMID: 34328079 PMCID: PMC8324302 DOI: 10.7554/elife.64108] [Citation(s) in RCA: 3] [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: 10/19/2020] [Accepted: 06/17/2021] [Indexed: 12/11/2022] Open
Abstract
Hydra vulgaris is an emerging model organism for neuroscience due to its small size, transparency, genetic tractability, and regenerative nervous system; however, fundamental properties of its sensorimotor behaviors remain unknown. Here, we use microfluidic devices combined with fluorescent calcium imaging and surgical resectioning to study how the diffuse nervous system coordinates Hydra's mechanosensory response. Mechanical stimuli cause animals to contract, and we find this response relies on at least two distinct networks of neurons in the oral and aboral regions of the animal. Different activity patterns arise in these networks depending on whether the animal is contracting spontaneously or contracting in response to mechanical stimulation. Together, these findings improve our understanding of how Hydra's diffuse nervous system coordinates sensorimotor behaviors. These insights help reveal how sensory information is processed in an animal with a diffuse, radially symmetric neural architecture unlike the dense, bilaterally symmetric nervous systems found in most model organisms.
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Affiliation(s)
| | - Abby S Primack
- Department of Molecular and Cellular BiologyUniversity of California, DavisUnited States
| | - Celina E Juliano
- Department of Molecular and Cellular BiologyUniversity of California, DavisUnited States
| | - Jacob T Robinson
- Department of Bioengineering, Rice UniversityHoustonUnited States
- Department of Electrical and Computer Engineering, Rice UniversityHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
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4
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Zulazmi NA, Arulsamy A, Ali I, Zainal Abidin SA, Othman I, Shaikh MF. The utilization of small non-mammals in traumatic brain injury research: A systematic review. CNS Neurosci Ther 2021; 27:381-402. [PMID: 33539662 PMCID: PMC7941175 DOI: 10.1111/cns.13590] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 12/07/2020] [Accepted: 12/14/2020] [Indexed: 12/20/2022] Open
Abstract
Traumatic brain injury (TBI) is the leading cause of death and disability worldwide and has complicated underlying pathophysiology. Numerous TBI animal models have been developed over the past decade to effectively mimic the human TBI pathophysiology. These models are of mostly mammalian origin including rodents and non-human primates. However, the mammalian models demanded higher costs and have lower throughput often limiting the progress in TBI research. Thus, this systematic review aims to discuss the potential benefits of non-mammalian TBI models in terms of their face validity in resembling human TBI. Three databases were searched as follows: PubMed, Scopus, and Embase, for original articles relating to non-mammalian TBI models, published between January 2010 and December 2019. A total of 29 articles were selected based on PRISMA model for critical appraisal. Zebrafish, both larvae and adult, was found to be the most utilized non-mammalian TBI model in the current literature, followed by the fruit fly and roundworm. In conclusion, non-mammalian TBI models have advantages over mammalian models especially for rapid, cost-effective, and reproducible screening of effective treatment strategies and provide an opportunity to expedite the advancement of TBI research.
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Affiliation(s)
- Nurul Atiqah Zulazmi
- Neuropharmacology Research LaboratoryJeffrey Cheah School of Medicine and Health SciencesMonash University MalaysiaSelangor Darul EhsanMalaysia
| | - Alina Arulsamy
- Neuropharmacology Research LaboratoryJeffrey Cheah School of Medicine and Health SciencesMonash University MalaysiaSelangor Darul EhsanMalaysia
| | - Idrish Ali
- Department of NeuroscienceCentral Clinical SchoolThe Alfred HospitalMonash UniversityMelbourneVic.Australia
| | - Syafiq Asnawi Zainal Abidin
- Neuropharmacology Research LaboratoryJeffrey Cheah School of Medicine and Health SciencesMonash University MalaysiaSelangor Darul EhsanMalaysia
- Liquid Chromatography Mass Spectrometry (LCMS) PlatformJeffrey Cheah School of Medicine and Health SciencesMonash University MalaysiaSelangor Darul EhsanMalaysia
| | - Iekhsan Othman
- Neuropharmacology Research LaboratoryJeffrey Cheah School of Medicine and Health SciencesMonash University MalaysiaSelangor Darul EhsanMalaysia
- Liquid Chromatography Mass Spectrometry (LCMS) PlatformJeffrey Cheah School of Medicine and Health SciencesMonash University MalaysiaSelangor Darul EhsanMalaysia
| | - Mohd. Farooq Shaikh
- Neuropharmacology Research LaboratoryJeffrey Cheah School of Medicine and Health SciencesMonash University MalaysiaSelangor Darul EhsanMalaysia
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5
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Vanhunsel S, Beckers A, Moons L. Designing neuroreparative strategies using aged regenerating animal models. Ageing Res Rev 2020; 62:101086. [PMID: 32492480 DOI: 10.1016/j.arr.2020.101086] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 04/13/2020] [Accepted: 05/08/2020] [Indexed: 12/13/2022]
Abstract
In our ever-aging world population, the risk of age-related neuropathies has been increasing, representing both a social and economic burden to society. Since the ability to regenerate in the adult mammalian central nervous system is very limited, brain trauma and neurodegeneration are often permanent. As a consequence, novel scientific challenges have emerged and many research efforts currently focus on triggering repair in the damaged or diseased brain. Nevertheless, stimulating neuroregeneration remains ambitious. Even though important discoveries have been made over the past decades, they did not translate into a therapy yet. Actually, this is not surprising; while these disorders mainly manifest in aged individuals, most of the research is being performed in young animal models. Aging of neurons and their environment, however, greatly affects the central nervous system and its capacity to repair. This review provides a detailed overview of the impact of aging on central nervous system functioning and regeneration potential, both in non-regenerating and spontaneously regenerating animal models. Additionally, we highlight the need for aging animal models with regenerative capacities in the search for neuroreparative strategies.
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Affiliation(s)
- Sophie Vanhunsel
- Laboratory of Neural Circuit Development and Regeneration, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, Leuven, Belgium
| | - An Beckers
- Laboratory of Neural Circuit Development and Regeneration, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, Leuven, Belgium
| | - Lieve Moons
- Laboratory of Neural Circuit Development and Regeneration, Animal Physiology and Neurobiology Section, Department of Biology, KU Leuven, Leuven, Belgium.
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6
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Coppa A, Guha S, Fourcade S, Parameswaran J, Ruiz M, Moser AB, Schlüter A, Murphy MP, Lizcano JM, Miranda-Vizuete A, Dalfó E, Pujol A. The peroxisomal fatty acid transporter ABCD1/PMP-4 is required in the C. elegans hypodermis for axonal maintenance: A worm model for adrenoleukodystrophy. Free Radic Biol Med 2020; 152:797-809. [PMID: 32017990 PMCID: PMC7611262 DOI: 10.1016/j.freeradbiomed.2020.01.177] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/20/2020] [Accepted: 01/20/2020] [Indexed: 02/07/2023]
Abstract
Adrenoleukodystrophy is a neurometabolic disorder caused by a defective peroxisomal ABCD1 transporter of very long-chain fatty acids (VLCFAs). Its pathogenesis is incompletely understood. Here we characterize a nematode model of X-ALD with loss of the pmp-4 gene, the worm orthologue of ABCD1. These mutants recapitulate the hallmarks of X-ALD: i) VLCFAs accumulation and impaired mitochondrial redox homeostasis and ii) axonal damage coupled to locomotor dysfunction. Furthermore, we identify a novel role for PMP-4 in modulating lipid droplet dynamics. Importantly, we show that the mitochondria targeted antioxidant MitoQ normalizes lipid droplets size, and prevents axonal degeneration and locomotor disability, highlighting its therapeutic potential. Moreover, PMP-4 acting solely in the hypodermis rescues axonal and locomotion abnormalities, suggesting a myelin-like role for the hypodermis in providing essential peroxisomal functions for the nematode nervous system.
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Affiliation(s)
- Andrea Coppa
- Neurometabolic Diseases Laboratory, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Duran i Reynals, L'Hospitalet de Llobregat, Spain
| | - Sanjib Guha
- Neurometabolic Diseases Laboratory, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Duran i Reynals, L'Hospitalet de Llobregat, Spain
| | - Stéphane Fourcade
- Neurometabolic Diseases Laboratory, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Duran i Reynals, L'Hospitalet de Llobregat, Spain; CIBERER U759, Center for Biomedical Research on Rare Diseases, Spain
| | - Janani Parameswaran
- Neurometabolic Diseases Laboratory, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Duran i Reynals, L'Hospitalet de Llobregat, Spain; CIBERER U759, Center for Biomedical Research on Rare Diseases, Spain
| | - Montserrat Ruiz
- Neurometabolic Diseases Laboratory, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Duran i Reynals, L'Hospitalet de Llobregat, Spain; CIBERER U759, Center for Biomedical Research on Rare Diseases, Spain
| | - Ann B Moser
- Peroxisomal Diseases Laboratory, Kennedy Krieger Institute, 707 N. Broadway, Baltimore, MD, 21205, USA
| | - Agatha Schlüter
- Neurometabolic Diseases Laboratory, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Duran i Reynals, L'Hospitalet de Llobregat, Spain; CIBERER U759, Center for Biomedical Research on Rare Diseases, Spain
| | | | - Jose Miguel Lizcano
- Departament de Bioquímica i Biologia Molecular, Institut de Neurociències, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193, Bellaterra (Barcelona), Spain
| | - Antonio Miranda-Vizuete
- Instituto de Biomedicina de Sevilla (IBIS), Hospital Universitario Virgen del Rocío /CSIC/ Universidad de Sevilla, E-41013, Sevilla, Spain
| | - Esther Dalfó
- Departament de Bioquímica i Biologia Molecular, Institut de Neurociències, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193, Bellaterra (Barcelona), Spain; Faculty of Medicine, University of Vic-Central University of Catalonia (UVic-UCC), 08500, Vic, Spain.
| | - Aurora Pujol
- Neurometabolic Diseases Laboratory, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Duran i Reynals, L'Hospitalet de Llobregat, Spain; CIBERER U759, Center for Biomedical Research on Rare Diseases, Spain; ICREA (Institució Catalana de Recerca i Estudis Avançats), Barcelona, Spain.
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7
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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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8
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Imperadore P, Uckermann O, Galli R, Steiner G, Kirsch M, Fiorito G. Nerve regeneration in the cephalopod mollusc Octopus vulgaris: label-free multiphoton microscopy as a tool for investigation. J R Soc Interface 2019; 15:rsif.2017.0889. [PMID: 29643223 DOI: 10.1098/rsif.2017.0889] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 03/16/2018] [Indexed: 01/16/2023] Open
Abstract
Octopus and cephalopods are able to regenerate injured tissues. Recent advancements in the study of regeneration in cephalopods appear promising encompassing different approaches helping to decipher cellular and molecular machinery involved in the process. However, lack of specific markers to investigate degenerative/regenerative phenomena and inflammatory events occurring after damage is limiting these studies. Label-free multiphoton microscopy is applied for the first time to the transected pallial nerve of Octopus vulgaris Various optical contrast methods including coherent anti-Stokes Raman scattering (CARS), endogenous two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) have been used. We detected cells and structures often not revealed with classical staining methods. CARS highlighted the involvement of haemocytes in building up scar tissue; CARS and TPEF facilitated the identification of degenerating fibres; SHG allowed visualization of fibrillary collagen, revealing the formation of a connective tissue bridge between the nerve stumps, likely involved in axon guidance. Using label-free multiphoton microscopy, we studied the regenerative events in octopus without using any other labelling techniques. These imaging methods provided extremely helpful morpho-chemical information to describe regeneration events. The techniques applied here are species-specific independent and should facilitate the comparison among various animal species.
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Affiliation(s)
- Pamela Imperadore
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy .,Association for Cephalopod Research - CephRes, 80133 Napoli, Italy
| | - Ortrud Uckermann
- Department of Neurosurgery, University Hospital Carl Gustav Carus and Faculty of Medicine, TU Dresden, Dresden, Germany
| | - Roberta Galli
- Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine, TU Dresden, Dresden, Germany
| | - Gerald Steiner
- Clinical Sensoring and Monitoring, Department of Anesthesiology and Intensive Care Medicine, Faculty of Medicine, TU Dresden, Dresden, Germany
| | - Matthias Kirsch
- Department of Neurosurgery, University Hospital Carl Gustav Carus and Faculty of Medicine, TU Dresden, Dresden, Germany.,CRTD/DFG-Center for Regenerative Therapies Dresden - Cluster of Excellence, TU Dresden, Dresden, Germany
| | - Graziano Fiorito
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy
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9
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Functional Genome-wide Screen Identifies Pathways Restricting Central Nervous System Axonal Regeneration. Cell Rep 2019; 23:415-428. [PMID: 29642001 DOI: 10.1016/j.celrep.2018.03.058] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 02/12/2018] [Accepted: 03/14/2018] [Indexed: 12/22/2022] Open
Abstract
Axonal regrowth is crucial for recovery from CNS injury but is severely restricted in adult mammals. We used a genome-wide loss-of-function screen for factors limiting axonal regeneration from cerebral cortical neurons in vitro. Knockdown of 16,007 individual genes identified 580 significant phenotypes. These molecules share no significant overlap with those suggested by previous expression profiles. There is enrichment for genes in pathways related to transport, receptor binding, and cytokine signaling, including Socs4 and Ship2. Among transport-regulating proteins, Rab GTPases are prominent. In vivo assessment with C. elegans validates a cell-autonomous restriction of regeneration by Rab27. Mice lacking Rab27b show enhanced retinal ganglion cell axon regeneration after optic nerve crush and greater motor function and raphespinal sprouting after spinal cord trauma. Thus, a comprehensive functional screen reveals multiple pathways restricting axonal regeneration and neurological recovery after injury.
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10
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Sundararajan L, Stern J, Miller DM. Mechanisms that regulate morphogenesis of a highly branched neuron in C. elegans. Dev Biol 2019; 451:53-67. [PMID: 31004567 DOI: 10.1016/j.ydbio.2019.04.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 03/09/2019] [Accepted: 04/05/2019] [Indexed: 02/08/2023]
Abstract
The shape of an individual neuron is linked to its function with axons sending signals to other cells and dendrites receiving them. Although much is known of the mechanisms for axonal outgrowth, the striking complexity of dendritic architecture has hindered efforts to uncover pathways that direct dendritic branching. Here we review the results of an experimental strategy that exploits the power of genetic analysis and live cell imaging of the PVD sensory neuron in C. elegans to reveal key molecular drivers of dendrite morphogenesis.
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Affiliation(s)
- Lakshmi Sundararajan
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - Jamie Stern
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA
| | - David M Miller
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240, USA.
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11
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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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12
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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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13
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Li J, Wang Q, Wang H, Wu Y, Yin J, Chen J, Zheng Z, Jiang T, Xie L, Wu F, Zhang H, Li X, Xu H, Xiao J. Lentivirus Mediating FGF13 Enhances Axon Regeneration after Spinal Cord Injury by Stabilizing Microtubule and Improving Mitochondrial Function. J Neurotrauma 2017; 35:548-559. [PMID: 28922963 DOI: 10.1089/neu.2017.5205] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Fibroblast growth factor 13 (FGF13), a nonsecretory protein of the FGF family, plays a crucial role in developing cortical neurons by stabilizing the microtubule. In previous studies, we showed that regulation of microtubule dynamics was instrumental for both growth cone initiation and for promoting regrowth of injured axon. However, the expression and effect of FGF13 in spinal cord or after spinal cord injury (SCI) remains undefined. Here, we demonstrated a role of FGF13 in regulating microtubule dynamics and in enhancing axon regeneration after SCI. Administration of FGF13 not only promoted neuronal polarization, axon formation, and growth cone initiation in vitro, but it also facilitated functional recovery following SCI. In addition, we found that upregulation of FGF13 in primary cortical neurons was accompanied by enhanced mitochondrial function, which is essential for axon regeneration. Our study has defined a novel mechanism underlying the beneficial effect of FGF13 on axon regeneration, pointing out that FGF13 may serve as a potential candidate for treating SCI or other central nervous system (CNS) injury.
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Affiliation(s)
- Jiawei Li
- 1 Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou, Zhejiang, China .,2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University , Wenzhou, Zhejiang, China
| | - Qingqing Wang
- 1 Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou, Zhejiang, China .,2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University , Wenzhou, Zhejiang, China
| | - Haoli Wang
- 1 Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou, Zhejiang, China .,2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University , Wenzhou, Zhejiang, China
| | - Yanqing Wu
- 3 The Institute of Life Sciences, Wenzhou University , Wenzhou, Zhejiang, China
| | - Jiayu Yin
- 2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University , Wenzhou, Zhejiang, China
| | - Jian Chen
- 1 Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou, Zhejiang, China .,2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University , Wenzhou, Zhejiang, China
| | - Zengming Zheng
- 1 Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou, Zhejiang, China .,2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University , Wenzhou, Zhejiang, China
| | - Ting Jiang
- 2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University , Wenzhou, Zhejiang, China
| | - Ling Xie
- 2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University , Wenzhou, Zhejiang, China
| | - Fenzan Wu
- 4 Department of Neurosurgery, Cixi People's Hospital, Wenzhou Medical University , Ningbo, Zhejiang, China
| | - Hongyu Zhang
- 2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University , Wenzhou, Zhejiang, China
| | - Xiaokun Li
- 3 The Institute of Life Sciences, Wenzhou University , Wenzhou, Zhejiang, China
| | - Huazi Xu
- 1 Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou, Zhejiang, China
| | - Jian Xiao
- 1 Department of Orthopaedics, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University , Wenzhou, Zhejiang, China .,2 Molecular Pharmacology Research Center, School of Pharmaceutical Science, Wenzhou Medical University , Wenzhou, Zhejiang, China
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14
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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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15
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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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16
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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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17
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Fang Y, Bonini NM. Hope on the (fruit) fly: the Drosophila wing paradigm of axon injury. Neural Regen Res 2015; 10:173-5. [PMID: 25883604 PMCID: PMC4392653 DOI: 10.4103/1673-5374.152359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/15/2014] [Indexed: 12/01/2022] Open
Affiliation(s)
- Yanshan Fang
- Interdisciplinary Research Center on Biology and Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Nancy M Bonini
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
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18
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Chin MR, Zlotkowski K, Han M, Patel S, Eliasen AM, Axelrod A, Siegel D. Expedited access to vinaxanthone and chemically edited derivatives possessing neuronal regenerative effects through ynone coupling reactions. ACS Chem Neurosci 2015; 6:542-50. [PMID: 25615693 DOI: 10.1021/cn500237z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The natural product vinaxanthone has demonstrated a remarkable capability to promote nerve growth following injury or transplantation. In rats following total transection of the spinal cord delivery of vinaxanthone enhanced axonal regeneration, remyelination and angiogenesis at the site of injury all leading to an improved reinstatement of motor function. Through the development of a new ynone coupling reaction, chemically edited derivatives of vinaxanthone have been prepared and studied for improved activity. The coupling reaction allows rapid access to new derivatives, wherein n ynone precursors provide n(2) vinaxanthone analogues. These compounds have been tested for their ability to promote neuronal regrowth using laser axotomy, severing axonal connections in Caenorhabditis elegans. This precise microsurgery using C. elegans allows a new in vivo approach for medicinal chemistry based optimization of neuronal growth promoting compounds.
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Affiliation(s)
- Matthew R. Chin
- Department
of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
- Skaggs
School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92039, United States
| | - Katherine Zlotkowski
- Department
of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
- Skaggs
School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92039, United States
| | - Michelle Han
- Department
of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Saagar Patel
- Department
of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Anders M. Eliasen
- Department
of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
- Skaggs
School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92039, United States
| | - Abram Axelrod
- Department
of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Dionicio Siegel
- Department
of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
- Skaggs
School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92039, United States
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19
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González-Hunt CP, Leung MCK, Bodhicharla RK, McKeever MG, Arrant AE, Margillo KM, Ryde IT, Cyr DD, Kosmaczewski SG, Hammarlund M, Meyer JN. Exposure to mitochondrial genotoxins and dopaminergic neurodegeneration in Caenorhabditis elegans. PLoS One 2014; 9:e114459. [PMID: 25486066 PMCID: PMC4259338 DOI: 10.1371/journal.pone.0114459] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 10/31/2014] [Indexed: 12/12/2022] Open
Abstract
Neurodegeneration has been correlated with mitochondrial DNA (mtDNA) damage and exposure to environmental toxins, but causation is unclear. We investigated the ability of several known environmental genotoxins and neurotoxins to cause mtDNA damage, mtDNA depletion, and neurodegeneration in Caenorhabditis elegans. We found that paraquat, cadmium chloride and aflatoxin B1 caused more mitochondrial than nuclear DNA damage, and paraquat and aflatoxin B1 also caused dopaminergic neurodegeneration. 6-hydroxydopamine (6-OHDA) caused similar levels of mitochondrial and nuclear DNA damage. To further test whether the neurodegeneration could be attributed to the observed mtDNA damage, C. elegans were exposed to repeated low-dose ultraviolet C radiation (UVC) that resulted in persistent mtDNA damage; this exposure also resulted in dopaminergic neurodegeneration. Damage to GABAergic neurons and pharyngeal muscle cells was not detected. We also found that fasting at the first larval stage was protective in dopaminergic neurons against 6-OHDA-induced neurodegeneration. Finally, we found that dopaminergic neurons in C. elegans are capable of regeneration after laser surgery. Our findings are consistent with a causal role for mitochondrial DNA damage in neurodegeneration, but also support non mtDNA-mediated mechanisms.
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Affiliation(s)
- Claudia P. González-Hunt
- Nicholas School of the Environment, Duke University, Durham, North Carolina, United States of America
| | - Maxwell C. K. Leung
- Nicholas School of the Environment, Duke University, Durham, North Carolina, United States of America
| | - Rakesh K. Bodhicharla
- Nicholas School of the Environment, Duke University, Durham, North Carolina, United States of America
| | - Madeline G. McKeever
- Nicholas School of the Environment, Duke University, Durham, North Carolina, United States of America
| | - Andrew E. Arrant
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, United States of America
| | - Kathleen M. Margillo
- Nicholas School of the Environment, Duke University, Durham, North Carolina, United States of America
| | - Ian T. Ryde
- Nicholas School of the Environment, Duke University, Durham, North Carolina, United States of America
| | - Derek D. Cyr
- Center for Applied Genomics and Technology, Duke University, Durham, North Carolina, United States of America
| | - Sara G. Kosmaczewski
- Department of Genetics, Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Marc Hammarlund
- Department of Genetics, Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Joel N. Meyer
- Nicholas School of the Environment, Duke University, Durham, North Carolina, United States of America
- * E-mail: mailto:
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20
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Gokce SK, Guo SX, Ghorashian N, Everett WN, Jarrell T, Kottek A, Bovik AC, Ben-Yakar A. A fully automated microfluidic femtosecond laser axotomy platform for nerve regeneration studies in C. elegans. PLoS One 2014; 9:e113917. [PMID: 25470130 PMCID: PMC4254741 DOI: 10.1371/journal.pone.0113917] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 10/30/2014] [Indexed: 11/29/2022] Open
Abstract
Femtosecond laser nanosurgery has been widely accepted as an axonal injury model, enabling nerve regeneration studies in the small model organism, Caenorhabditis elegans. To overcome the time limitations of manual worm handling techniques, automation and new immobilization technologies must be adopted to improve throughput in these studies. While new microfluidic immobilization techniques have been developed that promise to reduce the time required for axotomies, there is a need for automated procedures to minimize the required amount of human intervention and accelerate the axotomy processes crucial for high-throughput. Here, we report a fully automated microfluidic platform for performing laser axotomies of fluorescently tagged neurons in living Caenorhabditis elegans. The presented automation process reduces the time required to perform axotomies within individual worms to ∼17 s/worm, at least one order of magnitude faster than manual approaches. The full automation is achieved with a unique chip design and an operation sequence that is fully computer controlled and synchronized with efficient and accurate image processing algorithms. The microfluidic device includes a T-shaped architecture and three-dimensional microfluidic interconnects to serially transport, position, and immobilize worms. The image processing algorithms can identify and precisely position axons targeted for ablation. There were no statistically significant differences observed in reconnection probabilities between axotomies carried out with the automated system and those performed manually with anesthetics. The overall success rate of automated axotomies was 67.4±3.2% of the cases (236/350) at an average processing rate of 17.0±2.4 s. This fully automated platform establishes a promising methodology for prospective genome-wide screening of nerve regeneration in C. elegans in a truly high-throughput manner.
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Affiliation(s)
- Sertan Kutal Gokce
- Electrical and Computer Engineering, University of Texas, Austin, Texas, 78712, United States of America
| | - Samuel X. Guo
- Mechanical Engineering, University of Texas, Austin, Texas, 78705, United States of America
| | - Navid Ghorashian
- Biomedical Engineering, University of Texas, Austin, Texas, 78705, United States of America
| | - W. Neil Everett
- Mechanical Engineering, University of Texas, Austin, Texas, 78705, United States of America
| | - Travis Jarrell
- Mechanical Engineering, University of Texas, Austin, Texas, 78705, United States of America
| | - Aubri Kottek
- Mechanical Engineering, University of Texas, Austin, Texas, 78705, United States of America
| | - Alan C. Bovik
- Electrical and Computer Engineering, University of Texas, Austin, Texas, 78712, United States of America
| | - Adela Ben-Yakar
- Electrical and Computer Engineering, University of Texas, Austin, Texas, 78712, United States of America
- Mechanical Engineering, University of Texas, Austin, Texas, 78705, United States of America
- Biomedical Engineering, University of Texas, Austin, Texas, 78705, United States of America
- * E-mail:
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21
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An assay to image neuronal microtubule dynamics in mice. Nat Commun 2014; 5:4827. [PMID: 25219969 PMCID: PMC4175586 DOI: 10.1038/ncomms5827] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 07/25/2014] [Indexed: 01/03/2023] Open
Abstract
Microtubule dynamics in neurons play critical roles in physiology, injury and disease and determine microtubule orientation, the cell biological correlate of neurite polarization. Several microtubule binding proteins, including end-binding protein 3 (EB3), specifically bind to the growing plus tip of microtubules. In the past, fluorescently tagged end-binding proteins have revealed microtubule dynamics in vitro and in non-mammalian model organisms. Here, we devise an imaging assay based on transgenic mice expressing yellow fluorescent protein-tagged EB3 to study microtubules in intact mammalian neurites. Our approach allows measurement of microtubule dynamics in vivo and ex vivo in peripheral nervous system and central nervous system neurites under physiological conditions and after exposure to microtubule-modifying drugs. We find an increase in dynamic microtubules after injury and in neurodegenerative disease states, before axons show morphological indications of degeneration or regrowth. Thus increased microtubule dynamics might serve as a general indicator of neurite remodelling in health and disease.
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22
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Soares L, Parisi M, Bonini NM. Axon injury and regeneration in the adult Drosophila. Sci Rep 2014; 4:6199. [PMID: 25160612 PMCID: PMC4145289 DOI: 10.1038/srep06199] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 08/04/2014] [Indexed: 01/09/2023] Open
Abstract
Neural regeneration is a fascinating process with profound impact on human health, such that defining biological and genetic pathways is of interest. Here we describe an in vivo preparation for neuronal regeneration in the adult Drosophila. The nerve along the anterior margin of the wing is comprised of ~225 neurons that send projections into the central neuropil (thorax). Precise ablation can be induced with a pulsed laser to sever the entire axonal tract. The animal can be recovered, and response to injury assessed over time. Upon ablation, there is local loss of axons near the injury site, scar formation, a rapid impact on the cytoskeleton, and stimulation of hemocytes. By 7d, ~50% of animals show nerve regrowth, with axons from the nerve cells extending down towards the injury or re-routing. Inhibition of JNK signaling promotes regrowth through the injury site, enabling regeneration of the axonal tract.
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Affiliation(s)
- Lorena Soares
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Michael Parisi
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Nancy M Bonini
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
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23
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Donaldson K, Höke A. Studying axonal degeneration and regeneration using in vitro and in vivo models: the translational potential. FUTURE NEUROLOGY 2014. [DOI: 10.2217/fnl.14.29] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
ABSTRACT: Since the initial studies by Cajal, multiple models of peripheral nerve degeneration and regeneration have been developed to address the ever-increasing complexity of the mechanisms involved in regeneration. In vitro models offer the principal benefit of a system that can be readily manipulated to address specific mechanistic questions in a deconstructed system. However, in vitro models can be overly simplified and intricacies of the interactions between neurons and glia can be lost. In vivo animal models seek to remedy some of these shortcomings, but most in vivo animal systems fail to precisely model human nerve regeneration. Rodent models of chronic nerve regeneration have been developed to better recapitulate human nerve regeneration, but are not widely used. An important development in the field has been the establishment of experimental nerve regeneration in humans, involving the reinnervation of the epidermis after cutaneous axotomy or topical capsaicin application. Use of such human models will likely accelerate the development and evaluation of new drugs that enhance peripheral nerve regeneration.
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Affiliation(s)
- Katelyn Donaldson
- Departments of Neurology & Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Ahmet Höke
- Departments of Neurology & Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
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24
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Axon regeneration in C. elegans. Curr Opin Neurobiol 2014; 27:199-207. [PMID: 24794753 DOI: 10.1016/j.conb.2014.04.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 04/01/2014] [Accepted: 04/01/2014] [Indexed: 11/22/2022]
Abstract
Single axon transection by laser surgery has made Caenorhabditis elegans a new model for axon regeneration. Multiple conserved molecular signaling modules have been discovered through powerful genetic screening. In vivo imaging with single cell and axon resolution has revealed unprecedented cellular dynamics in regenerating axons. Information from C. elegans has greatly expanded our knowledge of the molecular and cellular mechanisms of axon regeneration.
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25
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Abstract
The ability of injured axons to regenerate declines with age, yet the mechanisms that regulate axon regeneration in response to age are not known. Here we show that axon regeneration in aging C. elegans motor neurons is inhibited by the conserved insulin/IGF1 receptor DAF-2. DAF-2's function in regeneration is mediated by intrinsic neuronal activity of the forkhead transcription factor DAF-16/FOXO. DAF-16 regulates regeneration independently of lifespan, indicating that neuronal aging is an intrinsic, neuron-specific, and genetically regulated process. In addition, we found that DAF-18/PTEN inhibits regeneration independently of age and FOXO signaling via the TOR pathway. Finally, DLK-1, a conserved regulator of regeneration, is downregulated by insulin/IGF1 signaling, bound by DAF-16 in neurons, and required for both DAF-16- and DAF-18-mediated regeneration. Together, our data establish that insulin signaling specifically inhibits regeneration in aging adult neurons and that this mechanism is independent of PTEN and TOR.
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26
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Chen D, Yu SP, Wei L. Ion channels in regulation of neuronal regenerative activities. Transl Stroke Res 2014; 5:156-62. [PMID: 24399572 DOI: 10.1007/s12975-013-0320-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 12/18/2013] [Accepted: 12/20/2013] [Indexed: 02/08/2023]
Abstract
The regeneration of the nervous system is achieved by the regrowth of damaged neuronal axons, the restoration of damaged nerve cells, and the generation of new neurons to replace those that have been lost. In the central nervous system, the regenerative ability is limited by various factors including damaged oligodendrocytes that are essential for neuronal axon myelination, an emerging glial scar, and secondary injury in the surrounding areas. Stem cell transplantation therapy has been shown to be a promising approach to treat neurodegenerative diseases because of the regenerative capability of the stem cells that secrete neurotrophic factors and give rise to differentiated progeny. However, some issues of stem cell transplantation, such as survival, homing, and efficiency of neural differentiation after transplantation, still need to be improved. Ion channels allow for the exchange of ions between the intra- and extracellular spaces or between the cytoplasm and organelles. These ion channels maintain the ion homeostasis in the brain and play a key role in regulating the physiological function of the nervous system and allowing the processing of neuronal signals. In seeking a potential strategy to enhance the efficacy of stem cell therapy in neurological and neurodegenerative diseases, this review briefly summarizes the roles of ion channels in cell proliferation, differentiation, migration, chemotropic axon guidance of growth cones, and axon outgrowth after injury.
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Affiliation(s)
- Dongdong Chen
- Department of Anesthesiology, Emory University School of Medicine, 101 Woodruff Circle, Atlanta, GA, 30322, USA
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27
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Fang Y, Soares L, Bonini NM. Design and implementation of in vivo imaging of neural injury responses in the adult Drosophila wing. Nat Protoc 2013; 8:810-9. [PMID: 23589940 DOI: 10.1038/nprot.2013.042] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Live-imaging technology has markedly advanced in the field of neural injury and axon degeneration; however, studies are still predominantly performed in in vitro settings such as cultured neuronal cells or in model organisms such as Caenorhabditis elegans in which axons lack glial wrappings. We recently developed a new in vivo model for adult-stage neural injury in Drosophila melanogaster, using the highly accessible wing of the animal. Because the Drosophila wing is translucent and dispensable for survival, it allows clear and direct visualization of injury-induced progressive responses of axons and glia highlighted by fluorescent protein (FP) markers in live animals over time. Moreover, unlike previous Drosophila models of neural injury, this procedure does not require dissection of the CNS. Thus, the key preparation steps for in vivo imaging of the neural injury response described in this protocol can be completed within 30 min.
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Affiliation(s)
- Yanshan Fang
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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28
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Saijilafu, Zhang BY, Zhou FQ. Signaling pathways that regulate axon regeneration. Neurosci Bull 2013; 29:411-20. [PMID: 23846598 DOI: 10.1007/s12264-013-1357-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 02/25/2013] [Indexed: 10/26/2022] Open
Abstract
Neurons in the mammalian central nervous system (CNS) cannot regenerate axons after injury. in contrast, neurons in the mammalian peripheral nervous system and in some non-mammalian models, such as C. elegans and Drosophila, are able to regrow axons. Understanding the molecular mechanisms by which these neurons support axon regeneration will help us find ways to enhance mammalian CNS axon regeneration. Here, recent studies in which signaling pathways regulating naturally-occurring axon regeneration that have been identified are reviewed, focusing on how these pathways control gene expression and growth-cone function during axon regeneration.
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Affiliation(s)
- Saijilafu
- Department of Orthopaedic Surgery, The Johns Hopkins University, Baltimore, Maryland, USA
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29
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Abstract
Axon regeneration after damage is widespread in the animal kingdom, and the nematode Caenorhabditis elegans has recently emerged as a tractable model in which to study the genetics and cell biology of axon regrowth in vivo. A key early step in axon regrowth is the conversion of part of a mature axon shaft into a growth cone-like structure, involving coordinated alterations in the microtubule, actin, and neurofilament systems. Recent attention has focused on microtubule dynamics as a determinant of axon-regrowth ability in several organisms. Live imaging studies have begun to reveal how the microtubule cytoskeleton is remodeled after axon injury, as well as the regulatory pathways involved. The dual leucine zipper kinase family of mixed-lineage kinases has emerged as a critical sensor of axon damage and plays a key role in regulating microtubule dynamics in the damaged axon.
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Affiliation(s)
- Andrew D Chisholm
- Division of Biological Sciences, Section of Neurobiology, University of California, San Diego, La Jolla, California 92093;
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30
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Spinal cord regeneration: where fish, frogs and salamanders lead the way, can we follow? Biochem J 2013; 451:353-64. [DOI: 10.1042/bj20121807] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Major trauma to the mammalian spinal cord often results in irreversible loss of function, i.e. paralysis, and current therapies ranging from drugs, implantations of stem cells and/or biomaterials, and electrically stimulated nerve regrowth, have so far offered very limited success in improving quality-of-life. However, in marked contrast with this basic shortcoming of ours, certain vertebrate species, including fish and salamanders, display the amazing ability to faithfully regenerate various complex body structures after injury or ablation, restoring full functionality, even in the case of the spinal cord. Despite the inherently strong and obvious translational potential for improving treatment strategies for human patients, our in-depth molecular-level understanding of these decidedly more advanced repair systems remains in its infancy. In the present review, we will discuss the current state of this field, focusing on recent progress in such molecular analyses using various regenerative species, and how these so far relate to the mammalian situation.
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