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Coakley S, Ritchie FK, Galbraith KM, Hilliard MA. Epidermal control of axonal attachment via β-spectrin and the GTPase-activating protein TBC-10 prevents axonal degeneration. Nat Commun 2020; 11:133. [PMID: 31919407 PMCID: PMC6952388 DOI: 10.1038/s41467-019-13795-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 11/28/2019] [Indexed: 12/28/2022] Open
Abstract
Neurons are subjected to strain due to body movement and their location within organs and tissues. However, how they withstand these forces over the lifetime of an organism is still poorly understood. Here, focusing on touch receptor neuron-epidermis interactions using Caenorhabditis elegans as a model system, we show that UNC-70/β-spectrin and TBC-10, a conserved GTPase-activating protein, function non-cell-autonomously within the epidermis to dynamically maintain attachment of the axon. We reveal that, in response to strain, UNC-70/β-spectrin and TBC-10 stabilize trans-epidermal hemidesmosome attachment structures which otherwise become lost, causing axonal breakage and degeneration. Furthermore, we show that TBC-10 regulates axonal attachment and maintenance by inactivating RAB-35, and reveal functional conservation of these molecules with their vertebrate orthologs. Finally, we demonstrate that β-spectrin functions in this context non-cell-autonomously. We propose a model in which mechanically resistant epidermal attachment structures are maintained by UNC-70/β-spectrin and TBC-10 during movement, preventing axonal detachment and degeneration.
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Affiliation(s)
- Sean Coakley
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Fiona K Ritchie
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Kate M Galbraith
- 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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Rohrscheib CE, Frentiu FD, Horn E, Ritchie FK, van Swinderen B, Weible MW, O’Neill SL, Brownlie JC. Response to: Comment on Rohrscheib et al. 2016 "Intensity of mutualism breakdown is determined by temperature not amplification of Wolbachia genes". PLoS Pathog 2017; 13:e1006521. [PMID: 28892518 PMCID: PMC5593257 DOI: 10.1371/journal.ppat.1006521] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 07/10/2017] [Indexed: 11/19/2022] Open
Affiliation(s)
- Chelsie E. Rohrscheib
- School of Natural Sciences, Griffith University, Nathan, Australia
- Griffith Research Institute for Drug Discovery, Griffith University, Nathan, Australia
| | - Francesca D. Frentiu
- Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Queensland University of Technology, Kelvin Grove, Australia
| | - Emilie Horn
- School of Natural Sciences, Griffith University, Nathan, Australia
| | - Fiona K. Ritchie
- School of Natural Sciences, Griffith University, Nathan, Australia
| | - Bruno van Swinderen
- Queensland Brain Institute, The University of Queensland, St. Lucia, Australia
| | - Michael W. Weible
- School of Natural Sciences, Griffith University, Nathan, Australia
- Griffith Research Institute for Drug Discovery, Griffith University, Nathan, Australia
| | - Scott L. O’Neill
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
| | - Jeremy C. Brownlie
- School of Natural Sciences, Griffith University, Nathan, Australia
- Environmental Futures Research Institute, Griffith University, Nathan, Australia
- * E-mail:
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Rohrscheib CE, Frentiu FD, Horn E, Ritchie FK, van Swinderen B, Weible MW, O’Neill SL, Brownlie JC. Intensity of Mutualism Breakdown Is Determined by Temperature Not Amplification of Wolbachia Genes. PLoS Pathog 2016; 12:e1005888. [PMID: 27661080 PMCID: PMC5035075 DOI: 10.1371/journal.ppat.1005888] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 08/22/2016] [Indexed: 11/18/2022] Open
Abstract
Wolbachia are maternally transmitted intracellular bacterial symbionts that infect approximately 40% of all insect species. Though several strains of Wolbachia naturally infect Drosophila melanogaster and provide resistance against viral pathogens, or provision metabolites during periods of nutritional stress, one virulent strain, wMelPop, reduces fly lifespan by half, possibly as a consequence of over-replication. While the mechanisms that allow wMelPop to over-replicate are still of debate, a unique tandem repeat locus in the wMelPop genome that contains eight genes, referred to as the “Octomom” locus has been identified and is thought to play an important regulatory role. Estimates of Octomom locus copy number correlated increasing copy number to both Wolbachia bacterial density and increased pathology. Here we demonstrate that infected fly pathology is not dependent on an increased Octomom copy number, but does strongly correlate with increasing temperature. When measured across developmental time, we also show Octomom copy number to be highly variable across developmental time within a single generation. Using a second pathogenic strain of Wolbachia, we further demonstrate reduced insect lifespan can occur independently of a high Octomom locus copy number. Taken together, this data demonstrates that the mechanism/s of wMelPop virulence is more complex than has been previously described. Wolbachia are obligate intracellular, symbiotic bacteria that infect approximately 40% of insect species, as well as filarial nematodes, arachnids and terrestrial isopods. While the vast majority of Wolbachia strains impose few fitness costs to their host, one strain wMelPop is unique as it lacks the ability to regulate its growth, and as consequence can reduce host lifespan by half. The strength of pathology induced by wMelPop has been linked to either increased bacterial density or copy number of an eight gene tandem repeat region referred to as the “Octomom” locus. To date no study has determined the effect changes to temperature have on Octomom copy number or bacterial density. Here we demonstrate that while the Octomom locus is unstable within a single generation of its host, changes to Octomom copy number did not occur in response to temperature. Furthermore, Octomom copy number or bacterial density does not correlate to the strength of pathology. These results indicate that the underpinning genetics of pathology are unclear, and the mechanisms by pathology is induced are more complex than previously realised.
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Affiliation(s)
- Chelsie E. Rohrscheib
- School of Natural Sciences, Griffith University, Nathan, Australia
- Eskitis Institute for Cell and Molecular Therapies, Griffith University, Nathan, Australia
| | - Francesca D. Frentiu
- Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Queensland University of Technology, Kelvin Grove, Australia
| | - Emilie Horn
- School of Natural Sciences, Griffith University, Nathan, Australia
| | - Fiona K. Ritchie
- School of Natural Sciences, Griffith University, Nathan, Australia
| | - Bruno van Swinderen
- Queensland Brain Institute, The University of Queensland, St. Lucia, Australia
| | - Michael W. Weible
- School of Natural Sciences, Griffith University, Nathan, Australia
- Eskitis Institute for Cell and Molecular Therapies, Griffith University, Nathan, Australia
| | - Scott L. O’Neill
- School of Biological Sciences, Monash University, Clayton, Australia
| | - Jeremy C. Brownlie
- School of Natural Sciences, Griffith University, Nathan, Australia
- Environmental Futures Research Institute, Griffith University, Nathan, Australia
- * E-mail:
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Ritchie FK, Toner IJ. Direct Labeling, Tester Expectancy and Delay Maintenance Behavior in Scottish Preschool Children. International Journal of Behavioral Development 2016. [DOI: 10.1177/016502548400700306] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The influence on Scottish preschool children's self-control of labels regarding patience given directly to the children themselves, and of the expectations regarding the children's patience provided to adult testers, was investigated. The children's self-control was assessed in a task in which each child's possession of accumulating candy rewards was made contingent upon the child's stopping of further accumulation. Preschool children directly labeled beforehand as "patient" demonstrated significantly longer delay maintenance than did preschoolers hearing a remark irrelevant to the task. A significant effect of tester expectancy was found, with children not directly labeled as "patient" beforehand being more sensitive to adult expectations than were labeled children.
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Seth A, Ritchie FK, Wibowo N, Lua LHL, Middelberg APJ. Non-carrier nanoparticles adjuvant modular protein vaccine in a particle-dependent manner. PLoS One 2015; 10:e0117203. [PMID: 25756283 PMCID: PMC4355484 DOI: 10.1371/journal.pone.0117203] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 12/20/2014] [Indexed: 11/18/2022] Open
Abstract
Nanoparticles are increasingly used to adjuvant vaccine formulations due to their biocompatibility, ease of manufacture and the opportunity to tailor their size, shape, and physicochemical properties. The efficacy of similarly-sized silica (Si-OH), poly (D,L-lactic-co-glycolic acid) (PLGA) and poly caprolactone (PCL) nanoparticles (nps) to adjuvant recombinant capsomere presenting antigenic M2e modular peptide from Influenza A virus (CapM2e) was investigated in vivo. Formulation of CapM2e with Si-OH or PLGA nps significantly boosted the immunogenicity of modular capsomeres, even though CapM2e was not actively attached to the nanoparticles prior to injection (i.e., formulation was by simple mixing). In contrast, PCL nps showed no significant adjuvant effect using this simple-mixing approach. The immune response induced by CapM2e alone or formulated with nps was antibody-biased with very high antigen-specific antibody titer and less than 20 cells per million splenocytes secreting interferon gamma. Modification of silica nanoparticle surface properties through amine functionalization and pegylation did not lead to significant changes in immune response. This study confirms that simple mixing-based formulation can lead to effective adjuvanting of antigenic protein, though with antibody titer dependent on nanoparticle physicochemical properties.
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Affiliation(s)
- Arjun Seth
- The University of Queensland, Australian Institute for Bioengineering and Nanotechnology, St. Lucia, QLD, Australia
| | - Fiona K Ritchie
- The University of Queensland, Australian Institute for Bioengineering and Nanotechnology, St. Lucia, QLD, Australia
| | - Nani Wibowo
- The University of Queensland, Australian Institute for Bioengineering and Nanotechnology, St. Lucia, QLD, Australia
| | - Linda H L Lua
- The University of Queensland, Protein Expression Facility, St Lucia, QLD, Australia
| | - Anton P J Middelberg
- The University of Queensland, Australian Institute for Bioengineering and Nanotechnology, St. Lucia, QLD, Australia
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Abstract
Hearing-impaired children were individually administered a task in which possession of accumulating candy rewards was made contingent upon the child's decision to stop any further accumulation of the candy. Hearing-impaired children, who under instruction periodically made American Sign Language (ASL) statements about the goodness of the reward, waited significantly longer before terminating the waiting period than did hearing-impaired children instructed to sign statements about the act of waiting and somewhat longer than did hearing-impaired children instructed to sign a neutral statement. Since the pattern of delay was unlike that reported in earlier investigations when nonhandicapped children verbalized similar statements and since variation in mode of communication did not influence delay in nonhandicapped children in the present investigation, the results were interpreted in terms of differences in cognitive controlling mechanisms between nonhandicapped and hearing-impaired children.
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