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Park S, Noblett N, Pitts L, Colavita A, Wehman AM, Jin Y, Chisholm AD. Dopey-dependent regulation of extracellular vesicles maintains neuronal morphology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.07.591898. [PMID: 38766017 PMCID: PMC11100700 DOI: 10.1101/2024.05.07.591898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Mature neurons maintain their distinctive morphology for extended periods in adult life. Compared to developmental neurite outgrowth, axon guidance, and target selection, relatively little is known of mechanisms that maintain mature neuron morphology. Loss of function in C. elegans DIP-2, a member of the conserved lipid metabolic regulator Dip2 family, results in progressive overgrowth of neurites in adults. We find that dip-2 mutants display specific genetic interactions with sax-2, the C. elegans ortholog of Drosophila Furry and mammalian FRY. Combined loss of DIP-2 and SAX-2 results in severe disruption of neuronal morphology maintenance accompanied by increased release of neuronal extracellular vesicles (EVs). By screening for suppressors of dip-2 sax-2 double mutant defects we identified gain-of-function (gf) mutations in the conserved Dopey family protein PAD-1 and its associated phospholipid flippase TAT-5/ATP9A. In dip-2 sax-2 double mutants carrying either pad-1(gf) or tat-5(gf) mutation, EV release is reduced and neuronal morphology across multiple neuron types is restored to largely normal. PAD-1(gf) acts cell autonomously in neurons. The domain containing pad-1(gf) is essential for PAD-1 function, and PAD-1(gf) protein displays increased association with the plasma membrane and inhibits EV release. Our findings uncover a novel functional network of DIP-2, SAX-2, PAD-1, and TAT-5 that maintains morphology of neurons and other types of cells, shedding light on the mechanistic basis of neurological disorders involving human orthologs of these genes.
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Affiliation(s)
- Seungmee Park
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Nathaniel Noblett
- Neuroscience Program, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Lauren Pitts
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - Antonio Colavita
- Neuroscience Program, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Ann M Wehman
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - Yishi Jin
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Andrew D Chisholm
- Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
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2
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Brar HK, Dey S, Singh P, Pande D, Ghosh-Roy A. Functional Recovery Associated with Dendrite Regeneration in PVD Neuron of Caenorhabditis elegans. eNeuro 2024; 11:ENEURO.0292-23.2024. [PMID: 38548333 PMCID: PMC7615967 DOI: 10.1523/eneuro.0292-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 02/18/2024] [Accepted: 03/03/2024] [Indexed: 05/02/2024] Open
Abstract
PVD neuron of Caenorhabditis elegans is a highly polarized cell with well-defined axonal, and dendritic compartments. PVD neuron operates in multiple sensory modalities including the control of both nociceptive touch sensation and body posture. Although both the axon and dendrites of this neuron show a regeneration response following laser-assisted injury, it is rather unclear how the behavior associated with this neuron is affected by the loss of these structures. It is also unclear whether neurite regrowth would lead to functional restoration in these neurons. Upon axotomy, using a femtosecond laser, we saw that harsh touch response was specifically affected leaving the body posture unperturbed. Subsequently, recovery in the touch response is highly correlated to the axon regrowth, which was dependent on DLK-1/MLK-1 MAP Kinase. Dendrotomy of both major and minor primary dendrites affected the wavelength and amplitude of sinusoidal movement without any apparent effect on harsh touch response. We further correlated the recovery in posture behavior to the type of dendrite regeneration events. We found that dendrite regeneration through the fusion and reconnection between the proximal and distal branches of the injured dendrite corresponded to improved recovery in posture. Our data revealed that the axons and dendrites of PVD neurons regulate the nociception and proprioception in worms, respectively. It also revealed that dendrite and axon regeneration lead to the restoration of these differential sensory modalities.
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Affiliation(s)
- Harjot Kaur Brar
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar 122052, Haryana, India
| | - Swagata Dey
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar 122052, Haryana, India
| | - Pallavi Singh
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar 122052, Haryana, India
| | - Devashish Pande
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar 122052, Haryana, India
| | - Anindya Ghosh-Roy
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar 122052, Haryana, India
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3
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Brukman NG, Valansi C, Podbilewicz B. Sperm induction of somatic cell-cell fusion as a novel functional test. eLife 2024; 13:e94228. [PMID: 38265078 PMCID: PMC10883674 DOI: 10.7554/elife.94228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 01/12/2024] [Indexed: 01/25/2024] Open
Abstract
The fusion of mammalian gametes requires the interaction between IZUMO1 on the sperm and JUNO on the oocyte. We have recently shown that ectopic expression of mouse IZUMO1 induces cell-cell fusion and that sperm can fuse to fibroblasts expressing JUNO. Here, we found that the incubation of mouse sperm with hamster fibroblasts or human epithelial cells in culture induces the fusion between these somatic cells and the formation of syncytia, a pattern previously observed with some animal viruses. This sperm-induced cell-cell fusion requires a species-matching JUNO on both fusing cells, can be blocked by an antibody against IZUMO1, and does not rely on the synthesis of new proteins. The fusion is dependent on the sperm's fusogenic capacity, making this a reliable, fast, and simple method for predicting sperm function during the diagnosis of male infertility.
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Affiliation(s)
- Nicolas G Brukman
- Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Clari Valansi
- Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
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Belew MY, Huang W, Florman JT, Alkema MJ, Byrne AB. PARP knockdown promotes synapse reformation after axon injury. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.03.565562. [PMID: 37961175 PMCID: PMC10635140 DOI: 10.1101/2023.11.03.565562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Injured nervous systems are often incapable of self-repairing, resulting in permanent loss of function and disability. To restore function, a severed axon must not only regenerate, but must also reform synapses with target cells. Together, these processes beget functional axon regeneration. Progress has been made towards a mechanistic understanding of axon regeneration. However, the molecular mechanisms that determine whether and how synapses are formed by a regenerated motor axon are not well understood. Using a combination of in vivo laser axotomy, genetics, and high-resolution imaging, we find that poly (ADP-ribose) polymerases (PARPs) inhibit synapse reformation in regenerating axons. As a result, regenerated parp(-) axons regain more function than regenerated wild-type axons, even though both have reached their target cells. We find that PARPs regulate both axon regeneration and synapse reformation in coordination with proteolytic calpain CLP-4. These results indicate approaches to functionally repair the injured nervous system must specifically target synapse reformation, in addition to other components of the injury response.
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5
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Vijayaraghavan T, Dhananjay S, Ho XY, Giordano-Santini R, Hilliard M, Neumann B. The dynamin GTPase mediates regenerative axonal fusion in Caenorhabditis elegans by regulating fusogen levels. PNAS NEXUS 2023; 2:pgad114. [PMID: 37181046 PMCID: PMC10167995 DOI: 10.1093/pnasnexus/pgad114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 01/29/2023] [Accepted: 03/21/2023] [Indexed: 05/16/2023]
Abstract
Axonal fusion is a neuronal repair mechanism that results in the reconnection of severed axon fragments, leading to the restoration of cytoplasmic continuity and neuronal function. While synaptic vesicle recycling has been linked to axonal regeneration, its role in axonal fusion remains unknown. Dynamin proteins are large GTPases that hydrolyze lipid-binding membranes to carry out clathrin-mediated synaptic vesicle recycling. Here, we show that the Caenorhabditis elegans dynamin protein DYN-1 is a key component of the axonal fusion machinery. Animals carrying a temperature-sensitive allele of dyn-1(ky51) displayed wild-type levels of axonal fusion at the permissive temperature (15°C) but presented strongly reduced levels at the restrictive temperature (25°C). Furthermore, the average length of regrowth was significantly diminished in dyn-1(ky51) animals at the restrictive temperature. The expression of wild-type DYN-1 cell-autonomously into dyn-1(ky51) mutant animals rescued both the axonal fusion and regrowth defects. Furthermore, DYN-1 was not required prior to axonal injury, suggesting that it functions specifically after injury to control axonal fusion. Finally, using epistatic analyses and superresolution imaging, we demonstrate that DYN-1 regulates the levels of the fusogen protein EFF-1 post-injury to mediate axonal fusion. Together, these results establish DYN-1 as a novel regulator of axonal fusion.
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Affiliation(s)
- Tarika Vijayaraghavan
- Neuroscience Programme, Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC 3800, Australia
| | - Samiksha Dhananjay
- Neuroscience Programme, Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC 3800, Australia
| | - Xue Yan Ho
- 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 Hilliard
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Brent Neumann
- Neuroscience Programme, Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC 3800, Australia
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6
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Zhao P, Mondal S, Martin C, DuPlissis A, Chizari S, Ma KY, Maiya R, Messing RO, Jiang N, Ben-Yakar A. Femtosecond laser microdissection for isolation of regenerating C. elegans neurons for single-cell RNA sequencing. Nat Methods 2023; 20:590-599. [PMID: 36928074 DOI: 10.1038/s41592-023-01804-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 01/26/2023] [Indexed: 03/18/2023]
Abstract
Our understanding of nerve regeneration can be enhanced by delineating its underlying molecular activities at single-neuron resolution in model organisms such as Caenorhabditis elegans. Existing cell isolation techniques cannot isolate neurons with specific regeneration phenotypes from C. elegans. We present femtosecond laser microdissection (fs-LM), a single-cell isolation method that dissects specific cells directly from living tissue by leveraging the micrometer-scale precision of fs-laser ablation. We show that fs-LM facilitates sensitive and specific gene expression profiling by single-cell RNA sequencing (scRNA-seq), while mitigating the stress-related transcriptional artifacts induced by tissue dissociation. scRNA-seq of fs-LM isolated regenerating neurons revealed transcriptional programs that are correlated with either successful or failed regeneration in wild-type and dlk-1 (0) animals, respectively. This method also allowed studying heterogeneity displayed by the same type of neuron and found gene modules with expression patterns correlated with axon regrowth rate. Our results establish fs-LM as a spatially resolved single-cell isolation method for phenotype-to-genotype mapping.
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Affiliation(s)
- Peisen Zhao
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Sudip Mondal
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Chris Martin
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Andrew DuPlissis
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Shahab Chizari
- Deparment of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Ke-Yue Ma
- Interdisciplinary Life Sciences Graduate Programs, The University of Texas at Austin, Austin, TX, USA
| | - Rajani Maiya
- Department of Neuroscience, The University of Texas at Austin, Austin, TX, USA
- Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
- Institute of Neuroscience, The University of Texas at Austin, Austin, TX, USA
- Department of Physiology, LSU Health Sciences Center, New Orleans, LA, USA
| | - Robert O Messing
- Department of Neuroscience, The University of Texas at Austin, Austin, TX, USA
- Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
- Institute of Neuroscience, The University of Texas at Austin, Austin, TX, USA
| | - Ning Jiang
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA
- Deparment of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
- Interdisciplinary Life Sciences Graduate Programs, The University of Texas at Austin, Austin, TX, USA
| | - Adela Ben-Yakar
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, USA.
- Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, USA.
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA.
- Institute of Neuroscience, The University of Texas at Austin, Austin, TX, USA.
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7
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Ryoden Y, Nagata S. The XK plasma membrane scramblase and the VPS13A cytosolic lipid transporter for ATP-induced cell death. Bioessays 2022; 44:e2200106. [PMID: 35996795 DOI: 10.1002/bies.202200106] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 07/25/2022] [Accepted: 08/08/2022] [Indexed: 11/12/2022]
Abstract
Extracellular ATP released from necrotic cells in inflamed tissues activates the P2X7 receptor, stimulates the exposure of phosphatidylserine, and causes cell lysis. Recent findings indicated that XK, a paralogue of XKR8 lipid scramblase, forms a complex with VPS13A at the plasma membrane of T cells. Upon engagement by ATP, an unidentified signal(s) from the P2X7 receptor activates the XK-VPS13A complex to scramble phospholipids, followed by necrotic cell death. P2X7 is expressed highly in CD25+ CD4+ T cells but weakly in CD8+ T cells, suggesting a role of this system in the activation of the immune system to prevent infection. On the other hand, a loss-of-function mutation in XK or VPS13A causes neuroacanthocytosis, indicating the crucial involvement of XK-VPS13A-mediated phospholipid scrambling at plasma membranes in the maintenance of homeostasis in the nervous and red blood cell systems.
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Affiliation(s)
- Yuta Ryoden
- Laboratory of Biochemistry and Immunology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Japan
| | - Shigekazu Nagata
- Laboratory of Biochemistry and Immunology, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Japan
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8
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Almasieh M, Faris H, Levin LA. Pivotal roles for membrane phospholipids in axonal degeneration. Int J Biochem Cell Biol 2022; 150:106264. [PMID: 35868612 DOI: 10.1016/j.biocel.2022.106264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/16/2022] [Accepted: 07/17/2022] [Indexed: 10/17/2022]
Abstract
Membrane phospholipids are critical components of several signaling pathways. Maintained in a variety of asymmetric distributions, their trafficking across the membrane can be induced by intra-, extra-, and intercellular events. A familiar example is the externalization of phosphatidylserine from the inner leaflet to the outer leaflet in apoptosis, inducing phagocytosis of the soma. Recently, it has been recognized that phospholipids in the axonal membrane may be a signal for axonal degeneration, regeneration, or other processes. This review focuses on key recent developments and areas for ongoing investigations. KEY FACTS: Phosphatidylserine externalization propagates along an axon after axonal injury and is delayed in the Wallerian degeneration slow (WldS) mutant. The ATP8A2 flippase mutant has spontaneous axonal degeneration. Microdomains of axonal degeneration in spheroid bodies have differential externalization of phosphatidylserine and phosphatidylethanolamine. Phospholipid trafficking could represent a mechanism for coordinated axonal degeneration and elimination, i.e. axoptosis, analogous to apoptosis of the cell body.
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Affiliation(s)
- Mohammadali Almasieh
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Hannah Faris
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada
| | - Leonard A Levin
- Department of Ophthalmology and Visual Sciences, McGill University, Montreal, Canada; Department of Neurology and Neurosurgery, McGill University, Montreal, Canada.
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9
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Vijayaraghavan T, Dhananjay S, Neumann B. DYN-1/dynamin regulates microtubule dynamics after axon injury. MICROPUBLICATION BIOLOGY 2022; 2022:10.17912/micropub.biology.000549. [PMID: 35622508 PMCID: PMC9005196 DOI: 10.17912/micropub.biology.000549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 03/25/2022] [Accepted: 04/04/2022] [Indexed: 11/14/2022]
Abstract
Microtubules play essential roles in the regeneration of axons after injury, but precisely how their growth is regulated remains to be resolved. Here, we studied the influence of the
C. elegans
DYN-1/dynamin GTPase protein on microtubule growth after axon injury. Before injury, loss of DYN-1 had no effect on microtubule dynamics compared to wild-type animals. However, significant increases in microtubule dynamics were observed after axotomy in animals lacking DYN-1. Moreover, a greater proportion of these animals displayed microtubule growth in the retrograde direction compared to wild-type controls. These data establish a role for DYN-1 in regulating microtubule dynamics after injury in
C. elegans
.
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Affiliation(s)
- Tarika Vijayaraghavan
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Samiksha Dhananjay
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria 3800, Australia
| | - Brent Neumann
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria 3800, Australia
,
Correspondence to: Brent Neumann (
)
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10
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Ho XY, Coakley S, Amor R, Anggono V, Hilliard MA. The metalloprotease ADM-4/ADAM17 promotes axonal repair. SCIENCE ADVANCES 2022; 8:eabm2882. [PMID: 35294233 PMCID: PMC8926332 DOI: 10.1126/sciadv.abm2882] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 01/25/2022] [Indexed: 05/28/2023]
Abstract
Axonal fusion is an efficient means of repair following axonal transection, whereby the regenerating axon fuses with its own separated axonal fragment to restore neuronal function. Despite being described over 50 years ago, its molecular mechanisms remain poorly understood. Here, we demonstrate that the Caenorhabditis elegans metalloprotease ADM-4, an ortholog of human ADAM17, is essential for axonal fusion. We reveal that animals lacking ADM-4 cannot repair their axons by fusion, and that ADM-4 has a cell-autonomous function within injured neurons, localizing at the tip of regrowing axon and fusion sites. We demonstrate that ADM-4 overexpression enhances fusion to levels higher than wild type, and that the metalloprotease and phosphatidylserine-binding domains are essential for its function. Last, we show that ADM-4 interacts with and stabilizes the fusogen EFF-1 to allow membranes to merge. Our results uncover a key role for ADM-4 in axonal fusion, exposing a molecular target for axonal repair.
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Affiliation(s)
- Xue Yan Ho
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Sean Coakley
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Rumelo Amor
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Victor Anggono
- 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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11
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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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12
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Regulation and functions of membrane lipids: Insights from Caenorhabditis elegans. BBA ADVANCES 2022; 2:100043. [PMID: 37082601 PMCID: PMC10074978 DOI: 10.1016/j.bbadva.2022.100043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/28/2021] [Accepted: 01/12/2022] [Indexed: 02/08/2023] Open
Abstract
The Caenorhabditis elegans plasma membrane is composed of glycerophospholipids and sphingolipids with a small cholesterol. The C. elegans obtain the majority of the membrane lipids by modifying fatty acids present in the bacterial diet. The metabolic pathways of membrane lipid biosynthesis are well conserved across the animal kingdom. In C. elegans CDP-DAG and Kennedy pathway produce glycerophospholipids. Meanwhile, the sphingolipids are synthesized through a different pathway. They have evolved remarkably diverse mechanisms to maintain membrane lipid homeostasis. For instance, the lipid bilayer stress operates to accomplish homeostasis during any perturbance in the lipid composition. Meanwhile, the PAQR-2/IGLR-2 complex works with FLD-1 to balance unsaturated to saturated fatty acids to maintain membrane fluidity. The loss of membrane lipid homeostasis is observed in many human genetic and metabolic disorders. Since C. elegans conserved such genes and pathways, it can be used as a model organism.
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13
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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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14
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Yong Y, Hunter-Chang S, Stepanova E, Deppmann C. Axonal spheroids in neurodegeneration. Mol Cell Neurosci 2021; 117:103679. [PMID: 34678457 PMCID: PMC8742877 DOI: 10.1016/j.mcn.2021.103679] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/12/2021] [Accepted: 10/15/2021] [Indexed: 10/20/2022] Open
Abstract
Axonal spheroids are bubble-like biological features that form on most degenerating axons, yet little is known about their influence on degenerative processes. Their formation and growth has been observed in response to various degenerative triggers such as injury, oxidative stress, inflammatory factors, and neurotoxic molecules. They often contain cytoskeletal elements and organelles, and, depending on the pathological insult, can colocalize with disease-related proteins such as amyloid precursor protein (APP), ubiquitin, and motor proteins. Initial formation of axonal spheroids depends on the disruption of axonal and membrane tension governed by cytoskeleton structure and calcium levels. Shortly after spheroid formation, the engulfment signal phosphatidylserine (PS) is exposed on the outer leaflet of spheroid plasma membrane, suggesting an important role for axonal spheroids in phagocytosis and debris clearance during degeneration. Spheroids can grow until they rupture, allowing pro-degenerative factors to exit the axon into extracellular space and accelerating neurodegeneration. Though much remains to be discovered in this area, axonal spheroid research promises to lend insight into the etiologies of neurodegenerative disease, and may be an important target for therapeutic intervention. This review summarizes over 100 years of work, describing what is known about axonal spheroid structure, regulation and function.
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Affiliation(s)
- Yu Yong
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Sarah Hunter-Chang
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22903, USA
| | - Ekaterina Stepanova
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Christopher Deppmann
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA; Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22903, USA.
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Swimming Exercise Promotes Post-injury Axon Regeneration and Functional Restoration through AMPK. eNeuro 2021; 8:ENEURO.0414-20.2021. [PMID: 34031101 PMCID: PMC8211466 DOI: 10.1523/eneuro.0414-20.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 04/16/2021] [Accepted: 04/25/2021] [Indexed: 12/11/2022] Open
Abstract
Restoration of lost function following a nervous system injury is limited in adulthood as the regenerative capacity of nervous system declines with age. Pharmacological approaches have not been very successful in alleviating the consequences of nervous system injury. On the contrary, physical activity and rehabilitation interventions are often beneficial to improve the health conditions in the patients with neuronal injuries. Using touch neuron circuit of Caenorhabditis elegans, we investigated the role of physical exercise in the improvement of functional restoration after axotomy. We found that a swimming session of 90 min following the axotomy of posterior lateral microtubule (PLM) neuron can improve functional recovery in larval and adult stage animals. In older age, multiple exercise sessions were required to enhance the functional recovery. Genetic analysis of axon regeneration mutants showed that exercise-mediated enhancement of functional recovery depends on the ability of axon to regenerate. Exercise promotes early initiation of regrowth, self-fusion of proximal and distal ends, as well as postregrowth enhancement of function. We further found that the swimming exercise promotes axon regeneration through the activity of cellular energy sensor AAK-2/AMPK in both muscle and neuron. Our study established a paradigm where systemic effects of exercise on functional regeneration could be addressed at the single neuron level.
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Basu A, Behera S, Bhardwaj S, Dey S, Ghosh-Roy A. Regulation of UNC-40/DCC and UNC-6/Netrin by DAF-16 promotes functional rewiring of the injured axon. Development 2021; 148:268990. [PMID: 34109380 DOI: 10.1242/dev.198044] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 05/04/2021] [Indexed: 01/02/2023]
Abstract
The adult nervous system has a limited capacity to regenerate after accidental damage. Post-injury functional restoration requires proper targeting of the injured axon to its postsynaptic cell. Although the initial response to axonal injury has been studied in great detail, it is rather unclear what controls the re-establishment of a functional connection. Using the posterior lateral microtubule neuron in Caenorhabditis elegans, we found that after axotomy, the regrowth from the proximal stump towards the ventral side and accumulation of presynaptic machinery along the ventral nerve cord correlated to the functional recovery. We found that the loss of insulin receptor DAF-2 promoted 'ventral targeting' in a DAF-16-dependent manner. We further showed that coordinated activities of DAF-16 in neuron and muscle promoted 'ventral targeting'. In response to axotomy, expression of the Netrin receptor UNC-40 was upregulated in the injured neuron in a DAF-16-dependent manner. In contrast, the DAF-2-DAF-16 axis contributed to the age-related decline in Netrin expression in muscle. Therefore, our study revealed an important role for insulin signaling in regulating the axon guidance molecules during the functional rewiring process.
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Affiliation(s)
- Atrayee Basu
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | - Sibaram Behera
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | - Smriti Bhardwaj
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
| | - Shirshendu Dey
- Fluorescence Microscopy Division, Bruker India Scientific PvT Ltd, International Trade Tower, Nehru Place, New Delhi 110019, India
| | - Anindya Ghosh-Roy
- Department of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Nainwal Mode, Gurgaon, Haryana 122051, India
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17
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Abstract
During multicellular organism development, complex structures are sculpted to form organs and tissues, which are maintained throughout adulthood. Many of these processes require cells to fuse with one another, or with themselves. These plasma membrane fusions merge endoplasmic cellular content across external, exoplasmic, space. In the nematode Caenorhabditis elegans, such cell fusions serve as a unique sculpting force, involved in the embryonic morphogenesis of the skin-like multinuclear hypodermal cells, but also in refining delicate structures, such as valve openings and the tip of the tail. During post-embryonic development, plasma membrane fusions continue to shape complex neuron structures and organs such as the vulva, while during adulthood fusion participates in cell and tissue repair. These processes rely on two fusion proteins (fusogens): EFF-1 and AFF-1, which are part of a broader family of structurally related membrane fusion proteins, encompassing sexual reproduction, viral infection, and tissue remodeling. The established capabilities of these exoplasmic fusogens are further expanded by new findings involving EFF-1 and AFF-1 in endocytic vesicle fission and phagosome sealing. Tight regulation by cell-autonomous and non-cell autonomous mechanisms orchestrates these diverse cell fusions at the correct place and time-these processes and their significance are discussed in this review.
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18
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Vest M, Guida A, Colombini C, Cordes K, Pena D, Maki M, Briones M, Antonio S, Hollifield C, Tian E, James L, Borashan C, Woodson J, Rovig J, Shihadeh H, Karabachev A, Brosious J, Pistorio A. Closing the Gap Between Mammalian and Invertebrate Peripheral Nerve Injury: Protocol for a Novel Nerve Repair. JMIR Res Protoc 2020; 9:e18706. [PMID: 32851981 PMCID: PMC7484768 DOI: 10.2196/18706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Outcomes after peripheral nerve injuries are poor despite current nerve repair techniques. Currently, there is no conclusive evidence that mammalian axons are capable of spontaneous fusion after transection. Notably, certain invertebrate species are able to auto-fuse after transection. Although mammalian axonal auto-fusion has not been observed experimentally, no mammalian study to date has demonstrated regenerating axolemmal membranes contacting intact distal segment axolemmal membranes to determine whether mammalian peripheral nerve axons have the intrinsic mechanisms necessary to auto-fuse after transection. OBJECTIVE This study aims to assess fusion competence between regenerating axons and intact distal segment axons by enhancing axon regeneration, delaying Wallerian degeneration, limiting the immune response, and preventing myelin obstruction. METHODS This study will use a rat sciatic nerve model to evaluate the effects of a novel peripheral nerve repair protocol on behavioral, electrophysiologic, and morphologic parameters. This protocol consists of a variety of preoperative, intraoperative, and postoperative interventions. Fusion will be assessed with electrophysiological conduction of action potentials across the repaired transection site. Axon-axon contact will be assessed with transmission electron microscopy. Behavioral recovery will be analyzed with the sciatic functional index. A total of 36 rats will be used for this study. The experimental group will use 24 rats and the negative control group will use 12 rats. For both the experimental and negative control groups, there will be both a behavior group and another group that will undergo electrophysiological and morphological analysis. The primary end point will be the presence or absence of action potentials across the lesion site. Secondary end points will include behavioral recovery with the sciatic functional index and morphological analysis of axon-axon contact between regenerating axons and intact distal segment axons. RESULTS The author is in the process of grant funding and institutional review board approval as of March 2020. The final follow-up will be completed by December 2021. CONCLUSIONS In this study, the efficacy of the proposed novel peripheral nerve repair protocol will be evaluated using behavioral and electrophysiologic parameters. The author believes this study will provide information regarding whether spontaneous axon fusion is possible in mammals under the proper conditions. This information could potentially be translated to clinical trials if successful to improve outcomes after peripheral nerve injury. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID) PRR1-10.2196/18706.
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Affiliation(s)
- Maxwell Vest
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Addison Guida
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Cory Colombini
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Kristina Cordes
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Diana Pena
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Marwa Maki
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Michael Briones
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Sabrina Antonio
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Carmen Hollifield
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Elli Tian
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Lucas James
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Christian Borashan
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Johnnie Woodson
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - John Rovig
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Hanaa Shihadeh
- Larner College of Medicine, University of Vermont, Burlington, VT, United States
| | - Alexander Karabachev
- Larner College of Medicine, University of Vermont, Burlington, VT, United States
| | - John Brosious
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Ashley Pistorio
- Department of Plastic and Reconstructive Surgery, University of Nevada Las Vegas, Las Vegas, NV, United States
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19
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Neumann B, Hilliard MA. Axonal repair by fusion: pitfalls, consequences and solutions. FASEB J 2020; 33:13071-13074. [PMID: 31795027 DOI: 10.1096/fj.201901407r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Brent Neumann
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia; and
| | - Massimo A Hilliard
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
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20
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Naeini MB, Bianconi V, Pirro M, Sahebkar A. The role of phosphatidylserine recognition receptors in multiple biological functions. Cell Mol Biol Lett 2020; 25:23. [PMID: 32226456 PMCID: PMC7098104 DOI: 10.1186/s11658-020-00214-z] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 03/04/2020] [Indexed: 02/06/2023] Open
Abstract
Apoptotic cells are rapidly engulfed and degraded by phagocytes through efferocytosis. Efferocytosis is a highly regulated process. It is triggered upon the activation of caspase-dependent apoptosis, which in turn promotes the expression of "eat me" signals on the surface of dying cells and the release of soluble "find me" signals for the recruitment of phagocytes. To date, many "eat me" signals have been recognized, including phosphatidylserine (PS), intercellular adhesion molecule-3, carbohydrates (e.g., amino sugars, mannose) and calreticulin. Among them, PS is the most studied one. PS recognition receptors are different functionally active receptors expressed by phagocytes. Various PS recognition receptors with different structure, cell type expression, and ability to bind to PS have been recognized. Although PS recognition receptors do not fall into a single classification or family of proteins due to their structural differences, they all share the common ability to activate downstream signaling pathways leading to the production of anti-inflammatory mediators. In this review, available evidence regarding molecular mechanisms underlying PS recognition receptor-regulated clearance of apoptotic cells is discussed. In addition, some efferocytosis-independent biological functions of PS recognition receptors are reviewed.
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Affiliation(s)
- Mehri Bemani Naeini
- Nanotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Vanessa Bianconi
- Unit of Internal Medicine, Angiology and Arteriosclerosis Diseases, Department of Medicine, University of Perugia, Perugia, Italy
| | - Matteo Pirro
- Unit of Internal Medicine, Angiology and Arteriosclerosis Diseases, Department of Medicine, University of Perugia, Perugia, Italy
| | - Amirhossein Sahebkar
- Halal Research Center of IRI, FDA, Tehran, Iran
- Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Medical Biotechnology, School of Medicine, Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, P.O. Box: 91779-48564, Mashhad, Iran
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21
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Phosphatidylserine modulates response to oxidative stress through hormesis and increases lifespan via DAF-16 in Caenorhabditis elegans. Biogerontology 2020; 21:231-244. [DOI: 10.1007/s10522-020-09856-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 01/03/2020] [Indexed: 12/22/2022]
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22
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Stabilin Receptors: Role as Phosphatidylserine Receptors. Biomolecules 2019; 9:biom9080387. [PMID: 31434355 PMCID: PMC6723754 DOI: 10.3390/biom9080387] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 08/16/2019] [Accepted: 08/18/2019] [Indexed: 12/18/2022] Open
Abstract
Phosphatidylserine is a membrane phospholipid that is localized to the inner leaflet of the plasma membrane. Phosphatidylserine externalization to the outer leaflet of the plasma membrane is an important signal for various physiological processes, including apoptosis, platelet activation, cell fusion, lymphocyte activation, and regenerative axonal fusion. Stabilin-1 and stabilin-2 are membrane receptors that recognize phosphatidylserine on the cell surface. Here, we discuss the functions of Stabilin-1 and stabilin-2 as phosphatidylserine receptors in apoptotic cell clearance (efferocytosis) and cell fusion, and their ligand-recognition and signaling pathways.
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23
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Ding C, Hammarlund M. Mechanisms of injury-induced axon degeneration. Curr Opin Neurobiol 2019; 57:171-178. [PMID: 31071521 DOI: 10.1016/j.conb.2019.03.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/10/2019] [Accepted: 03/13/2019] [Indexed: 12/18/2022]
Abstract
Injury-induced axon degeneration in model organisms and cell culture has emerged as an area of growing interest due to its experimental tractability and to the promise of identifying conserved mechanisms that mediate axon loss in human disease. Injury-induced axon degeneration is also observed within the well-studied process of Wallerian degeneration, a complex phenomenon triggered by axon injury to peripheral nerves in mammals. Recent studies have led to the identification of key molecular components of injury-induced axon degeneration. Axon survival factors, such as NMNAT2, act to protect injured axons from degeneration. By contrast, factors such as SARM1, MAPK, and PHR1 act to promote degeneration. The coordinated activity of these factors determines axon fate after injury. Since axon loss is an early feature of neurodegenerative diseases, it is possible that understanding the molecular mechanism of injury-induced degeneration will lead to new treatments for axon loss in neurodegenerative disease. Here, we discuss the critical pathways for injury-induced axon degeneration across species with an emphasis on their interactions in an integrated signaling network.
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Affiliation(s)
- Chen Ding
- Department of Neuroscience, Yale University, New Haven, United States
| | - Marc Hammarlund
- Department of Neuroscience, Yale University, New Haven, United States; Department of Genetics, Yale University, New Haven, United States.
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24
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Byrne JJ, Soh MS, Chandhok G, Vijayaraghavan T, Teoh JS, Crawford S, Cobham AE, Yapa NMB, Mirth CK, Neumann B. Disruption of mitochondrial dynamics affects behaviour and lifespan in Caenorhabditis elegans. Cell Mol Life Sci 2019; 76:1967-1985. [PMID: 30840087 PMCID: PMC6478650 DOI: 10.1007/s00018-019-03024-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 01/11/2019] [Accepted: 01/22/2019] [Indexed: 01/29/2023]
Abstract
Mitochondria are essential components of eukaryotic cells, carrying out critical physiological processes that include energy production and calcium buffering. Consequently, mitochondrial dysfunction is associated with a range of human diseases. Fundamental to their function is the ability to transition through fission and fusion states, which is regulated by several GTPases. Here, we have developed new methods for the non-subjective quantification of mitochondrial morphology in muscle and neuronal cells of Caenorhabditis elegans. Using these techniques, we uncover surprising tissue-specific differences in mitochondrial morphology when fusion or fission proteins are absent. From ultrastructural analysis, we reveal a novel role for the fusion protein FZO-1/mitofusin 2 in regulating the structure of the inner mitochondrial membrane. Moreover, we have determined the influence of the individual mitochondrial fission (DRP-1/DRP1) and fusion (FZO-1/mitofusin 1,2; EAT-3/OPA1) proteins on animal behaviour and lifespan. We show that loss of these mitochondrial fusion or fission regulators induced age-dependent and progressive deficits in animal movement, as well as in muscle and neuronal function. Our results reveal that disruption of fusion induces more profound defects than lack of fission on animal behaviour and tissue function, and imply that while fusion is required throughout life, fission is more important later in life likely to combat ageing-associated stressors. Furthermore, our data demonstrate that mitochondrial function is not strictly dependent on morphology, with no correlation found between morphological changes and behavioural defects. Surprisingly, we find that disruption of either mitochondrial fission or fusion significantly reduces median lifespan, but maximal lifespan is unchanged, demonstrating that mitochondrial dynamics play an important role in limiting variance in longevity across isogenic populations. Overall, our study provides important new insights into the central role of mitochondrial dynamics in maintaining organismal health.
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Affiliation(s)
- Joseph J Byrne
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - Ming S Soh
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - Gursimran Chandhok
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - Tarika Vijayaraghavan
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - Jean-Sébastien Teoh
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - Simon Crawford
- Monash Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Melbourne, VIC, 3800, Australia
| | - Ansa E Cobham
- School of Biological Sciences, Monash University, Melbourne, VIC, 3800, Australia
| | - Nethmi M B Yapa
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - Christen K Mirth
- School of Biological Sciences, Monash University, Melbourne, VIC, 3800, Australia
| | - Brent Neumann
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia.
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25
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Brukman NG, Uygur B, Podbilewicz B, Chernomordik LV. How cells fuse. J Cell Biol 2019; 218:1436-1451. [PMID: 30936162 PMCID: PMC6504885 DOI: 10.1083/jcb.201901017] [Citation(s) in RCA: 113] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 03/05/2019] [Accepted: 03/08/2019] [Indexed: 12/11/2022] Open
Abstract
Brukman et al. review cell–cell fusion mechanisms, focusing on the identity of the fusogens that mediate these processes and the regulation of their activities. Cell–cell fusion remains the least understood type of membrane fusion process. However, the last few years have brought about major advances in understanding fusion between gametes, myoblasts, macrophages, trophoblasts, epithelial, cancer, and other cells in normal development and in diseases. While different cell fusion processes appear to proceed via similar membrane rearrangements, proteins that have been identified as necessary and sufficient for cell fusion (fusogens) use diverse mechanisms. Some fusions are controlled by a single fusogen; other fusions depend on several proteins that either work together throughout the fusion pathway or drive distinct stages. Furthermore, some fusions require fusogens to be present on both fusing membranes, and in other fusions, fusogens have to be on only one of the membranes. Remarkably, some of the proteins that fuse cells also sculpt single cells, repair neurons, promote scission of endocytic vesicles, and seal phagosomes. In this review, we discuss the properties and diversity of the known proteins mediating cell–cell fusion and highlight their different working mechanisms in various contexts.
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Affiliation(s)
- Nicolas G Brukman
- Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Berna Uygur
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | | | - Leonid V Chernomordik
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
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26
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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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27
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Caneo M, Julian V, Byrne AB, Alkema MJ, Calixto A. Diapause induces functional axonal regeneration after necrotic insult in C. elegans. PLoS Genet 2019; 15:e1007863. [PMID: 30640919 PMCID: PMC6347329 DOI: 10.1371/journal.pgen.1007863] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 01/25/2019] [Accepted: 11/29/2018] [Indexed: 02/07/2023] Open
Abstract
Many neurons are unable to regenerate after damage. The ability to regenerate after an insult depends on life stage, neuronal subtype, intrinsic and extrinsic factors. C. elegans is a powerful model to test the genetic and environmental factors that affect axonal regeneration after damage, since its axons can regenerate after neuronal insult. Here we demonstrate that diapause promotes the complete morphological regeneration of truncated touch receptor neuron (TRN) axons expressing a neurotoxic MEC-4(d) DEG/ENaC channel. Truncated axons of different lengths were repaired during diapause and we observed potent axonal regrowth from somas alone. Complete morphological regeneration depends on DLK-1 but neuronal sprouting and outgrowth is DLK-1 independent. We show that TRN regeneration is fully functional since animals regain their ability to respond to mechanical stimulation. Thus, diapause induced regeneration provides a simple model of complete axonal regeneration which will greatly facilitate the study of environmental and genetic factors affecting the rate at which neurons die.
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Affiliation(s)
- Mauricio Caneo
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago de Chile, Chile
- Centro Interdisciplinario de Neurociencias de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaiso, Chile
| | - Victoria Julian
- Neurobiology Department, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Alexandra B. Byrne
- Neurobiology Department, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Mark J. Alkema
- Neurobiology Department, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Andrea Calixto
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago de Chile, Chile
- Centro Interdisciplinario de Neurociencias de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaiso, Chile
- * E-mail: ,
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28
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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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Ding C, Hammarlund M. Aberrant information transfer interferes with functional axon regeneration. eLife 2018; 7:38829. [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] [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 Neuroscience, Yale University, New Haven, United States
| | - Marc Hammarlund
- Department of Neuroscience, Yale University, New Haven, United States.,Department of Genetics, Yale University, New Haven, United States
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Tang HM, Tang HL. Anastasis: recovery from the brink of cell death. ROYAL SOCIETY OPEN SCIENCE 2018; 5:180442. [PMID: 30839720 PMCID: PMC6170572 DOI: 10.1098/rsos.180442] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 08/23/2018] [Indexed: 05/11/2023]
Abstract
Anastasis is a natural cell recovery phenomenon that rescues cells from the brink of death. Programmed cell death such as apoptosis has been traditionally assumed to be an intrinsically irreversible cascade that commits cells to a rapid and massive demolition. Interestingly, recent studies have demonstrated recovery of dying cells even at the late stages generally considered immutable. Here, we examine the evidence for anastasis in cultured cells and in animals, review findings illuminating the potential mechanisms of action, discuss the challenges of studying anastasis and explore new strategies to uncover the function and regulation of anastasis, the identification of which has wide-ranging physiological, pathological and therapeutic implications.
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Affiliation(s)
- Ho Man Tang
- Institute for Basic Biomedical Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- School of Life Sciences, Chinese University of Hong Kong, Shatin, Hong Kong
| | - Ho Lam Tang
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Teoh JS, Wong MYY, Vijayaraghavan T, Neumann B. Bridging the gap: axonal fusion drives rapid functional recovery of the nervous system. Neural Regen Res 2018; 13:591-594. [PMID: 29722300 PMCID: PMC5950658 DOI: 10.4103/1673-5374.230271] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Injuries to the central or peripheral nervous system frequently cause long-term disabilities because damaged neurons are unable to efficiently self-repair. This inherent deficiency necessitates the need for new treatment options aimed at restoring lost function to patients. Compared to humans, a number of species possess far greater regenerative capabilities, and can therefore provide important insights into how our own nervous systems can be repaired. In particular, several invertebrate species have been shown to rapidly initiate regeneration post-injury, allowing separated axon segments to re-join. This process, known as axonal fusion, represents a highly efficient repair mechanism as a regrowing axon needs to only bridge the site of damage and fuse with its separated counterpart in order to re-establish its original structure. Our recent findings in the nematode Caenorhabditis elegans have expanded the promise of axonal fusion by demonstrating that it can restore complete function to damaged neurons. Moreover, we revealed the importance of injury-induced changes in the composition of the axonal membrane for mediating axonal fusion, and discovered that the level of axonal fusion can be enhanced by promoting a neuron's intrinsic growth potential. A complete understanding of the molecular mechanisms controlling axonal fusion may permit similar approaches to be applied in a clinical setting.
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Affiliation(s)
- Jean-Sébastien Teoh
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia
| | - Michelle Yu-Ying Wong
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia
| | - Tarika Vijayaraghavan
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia
| | - Brent Neumann
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Australia
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Abay ZC, Wong MYY, Neumann B. daf-2 modulates regeneration of mechanosensory neurons II. MICROPUBLICATION BIOLOGY 2017; 2017:10.17912/W2SM1T. [PMID: 32550345 PMCID: PMC7255863 DOI: 10.17912/w2sm1t] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Zehra C. Abay
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne VIC 3800, Australia
| | - Michelle Yu-Ying Wong
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne VIC 3800, Australia
| | - Brent Neumann
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne VIC 3800, Australia,
Correspondence to: Brent Neumann ()
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Abay ZC, Wong MYY, Neumann B. daf-2 regeneration of mechanosensory neurons: integration. MICROPUBLICATION BIOLOGY 2017; 2017:10.17912/W2NW9C. [PMID: 32550348 PMCID: PMC7255867 DOI: 10.17912/w2nw9c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Zehra C. Abay
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne VIC 3800, Australia
| | - Michelle Yu-Ying Wong
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne VIC 3800, Australia
| | - Brent Neumann
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne VIC 3800, Australia,
Correspondence to: Brent Neumann ()
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Abay ZC, Wong MYY, Neumann B. daf-2 modulates regeneration of mechanosensory neurons I. MICROPUBLICATION BIOLOGY 2017; 2017:10.17912/W2XD3R. [PMID: 32550350 PMCID: PMC7255869 DOI: 10.17912/w2xd3r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Zehra C. Abay
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne VIC 3800, Australia
| | - Michelle Yu-Ying Wong
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne VIC 3800, Australia
| | - Brent Neumann
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne VIC 3800, Australia,
Correspondence to: Brent Neumann ()
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