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Pan X, Hu Y, Lei G, Wei Y, Li J, Luan T, Zhang Y, Chu Y, Feng Y, Zhan W, Zhao C, Meunier FA, Liu Y, Li Y, Wang T. Actomyosin-II protects axons from degeneration induced by mild mechanical stress. J Cell Biol 2024; 223:e202206046. [PMID: 38713825 PMCID: PMC11076810 DOI: 10.1083/jcb.202206046] [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: 06/19/2022] [Revised: 06/16/2023] [Accepted: 04/09/2024] [Indexed: 05/09/2024] Open
Abstract
Whether, to what extent, and how the axons in the central nervous system (CNS) can withstand sudden mechanical impacts remain unclear. By using a microfluidic device to apply controlled transverse mechanical stress to axons, we determined the stress levels that most axons can withstand and explored their instant responses at nanoscale resolution. We found mild stress triggers a highly reversible, rapid axon beading response, driven by actomyosin-II-dependent dynamic diameter modulations. This mechanism contributes to hindering the long-range spread of stress-induced Ca2+ elevations into non-stressed neuronal regions. Through pharmacological and molecular manipulations in vitro, we found that actomyosin-II inactivation diminishes the reversible beading process, fostering progressive Ca2+ spreading and thereby increasing acute axonal degeneration in stressed axons. Conversely, upregulating actomyosin-II activity prevents the progression of initial injury, protecting stressed axons from acute degeneration both in vitro and in vivo. Our study unveils the periodic actomyosin-II in axon shafts cortex as a novel protective mechanism, shielding neurons from detrimental effects caused by mechanical stress.
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Affiliation(s)
- Xiaorong Pan
- The Brain Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yiqing Hu
- The Brain Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Gaowei Lei
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences China, Shanghai, China
| | - Yaxuan Wei
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences China, Shanghai, China
| | - Jie Li
- Division of Chemistry and Physical Biology, School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
- Shanghai Clinical Research and Trial Center, Shanghai, China
| | - Tongshu Luan
- The Brain Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yunfan Zhang
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences China, Shanghai, China
| | - Yuanyuan Chu
- The Brain Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yu Feng
- The Brain Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Wenrong Zhan
- The Brain Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Chunxia Zhao
- School of Chemical Engineering, The University of Adelaide, Adelaide, Australia
| | - Frédéric A. Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
- School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Yifan Liu
- Division of Chemistry and Physical Biology, School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
- Shanghai Clinical Research and Trial Center, Shanghai, China
| | - Yi Li
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences China, Shanghai, China
| | - Tong Wang
- The Brain Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, China
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2
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Song H, Tomasevich A, Paolini A, Browne KD, Wofford KL, Kelley B, Kantemneni E, Kennedy J, Qiu Y, Schneider ALC, Dolle JP, Cullen DK, Smith DH. Sex differences in the extent of acute axonal pathologies after experimental concussion. Acta Neuropathol 2024; 147:79. [PMID: 38705966 PMCID: PMC11070329 DOI: 10.1007/s00401-024-02735-9] [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: 01/22/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 05/07/2024]
Abstract
Although human females appear be at a higher risk of concussion and suffer worse outcomes than males, underlying mechanisms remain unclear. With increasing recognition that damage to white matter axons is a key pathologic substrate of concussion, we used a clinically relevant swine model of concussion to explore potential sex differences in the extent of axonal pathologies. At 24 h post-injury, female swine displayed a greater number of swollen axonal profiles and more widespread loss of axonal sodium channels than males. Axon degeneration for both sexes appeared to be related to individual axon architecture, reflected by a selective loss of small caliber axons after concussion. However, female brains had a higher percentage of small caliber axons, leading to more extensive axon loss after injury compared to males. Accordingly, sexual dimorphism in axonal size is associated with more extensive axonal pathology in females after concussion, which may contribute to worse outcomes.
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Affiliation(s)
- Hailong Song
- Department of Neurosurgery, Center for Brain Injury and Repair, University of Pennsylvania, 3320 Smith Walk, 105 Hayden Hall, Philadelphia, PA, 19104, USA
| | - Alexandra Tomasevich
- Department of Neurosurgery, Center for Brain Injury and Repair, University of Pennsylvania, 3320 Smith Walk, 105 Hayden Hall, Philadelphia, PA, 19104, USA
| | - Andrew Paolini
- Department of Neurosurgery, Center for Brain Injury and Repair, University of Pennsylvania, 3320 Smith Walk, 105 Hayden Hall, Philadelphia, PA, 19104, USA
| | - Kevin D Browne
- Department of Neurosurgery, Center for Brain Injury and Repair, University of Pennsylvania, 3320 Smith Walk, 105 Hayden Hall, Philadelphia, PA, 19104, USA
- Center for Neurotrauma, Neurodegeneration and Restoration, Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, 19104, USA
| | - Kathryn L Wofford
- Department of Neurosurgery, Center for Brain Injury and Repair, University of Pennsylvania, 3320 Smith Walk, 105 Hayden Hall, Philadelphia, PA, 19104, USA
- Center for Neurotrauma, Neurodegeneration and Restoration, Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, 19104, USA
| | - Brian Kelley
- Department of Neurosurgery, Center for Brain Injury and Repair, University of Pennsylvania, 3320 Smith Walk, 105 Hayden Hall, Philadelphia, PA, 19104, USA
| | - Eashwar Kantemneni
- Department of Neurosurgery, Center for Brain Injury and Repair, University of Pennsylvania, 3320 Smith Walk, 105 Hayden Hall, Philadelphia, PA, 19104, USA
| | - Justin Kennedy
- Department of Neurosurgery, Center for Brain Injury and Repair, University of Pennsylvania, 3320 Smith Walk, 105 Hayden Hall, Philadelphia, PA, 19104, USA
| | - Yue Qiu
- Department of Neurosurgery, Center for Brain Injury and Repair, University of Pennsylvania, 3320 Smith Walk, 105 Hayden Hall, Philadelphia, PA, 19104, USA
| | - Andrea L C Schneider
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Epidemiology, Biostatistics, and Informatics, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jean-Pierre Dolle
- Department of Neurosurgery, Center for Brain Injury and Repair, University of Pennsylvania, 3320 Smith Walk, 105 Hayden Hall, Philadelphia, PA, 19104, USA
| | - D Kacy Cullen
- Department of Neurosurgery, Center for Brain Injury and Repair, University of Pennsylvania, 3320 Smith Walk, 105 Hayden Hall, Philadelphia, PA, 19104, USA
- Center for Neurotrauma, Neurodegeneration and Restoration, Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, 19104, USA
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Douglas H Smith
- Department of Neurosurgery, Center for Brain Injury and Repair, University of Pennsylvania, 3320 Smith Walk, 105 Hayden Hall, Philadelphia, PA, 19104, USA.
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3
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Bakhtiarydavijani A, Stone TW. Impact of prior axonal injury on subsequent injury during brain tissue stretching - A mesoscale computational approach. J Mech Behav Biomed Mater 2024; 153:106489. [PMID: 38428206 DOI: 10.1016/j.jmbbm.2024.106489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 02/24/2024] [Accepted: 02/26/2024] [Indexed: 03/03/2024]
Abstract
Epidemiology studies of traumatic brain injury (TBI) show individuals with a prior history of TBI experience an increased risk of future TBI with a significantly more detrimental outcome. But the mechanisms through which prior head injuries may affect risks of injury during future head insults have not been identified. In this work, we show that prior brain tissue injury in the form of mechanically induced axonal injury and glial scar formation can facilitate future mechanically induced tissue injury. To achieve this, we use finite element computational models of brain tissue and a history-dependent pathophysiology-based mechanically-induced axonal injury threshold to determine the evolution of axonal injury and scar tissue formation and their effects on future brain tissue stretching. We find that due to the reduced stiffness of injured tissue and glial scars, the existence of prior injury can increase the risk of future injury in the vicinity of prior injury during future brain tissue stretching. The softer brain scar tissue is shown to increase the strain and strain rate in its vicinity by as much as 40% in its vicinity during dynamic stretching that reduces the global strain required to induce injury by 20% when deformed at 15 s-1 strain rate. The results of this work highlight the need to account for patient history when determining the risk of brain injury.
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Affiliation(s)
| | - Tonya W Stone
- Center for Advanced Vehicular Systems, Mississippi State University, Starkville, MS, 39759, USA; Department of Mechanical Engineering, Mississippi State University, Mississippi State, MS, 39762, USA
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4
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Krieg JL, Leonard AV, Turner RJ, Corrigan F. Identifying the Phenotypes of Diffuse Axonal Injury Following Traumatic Brain Injury. Brain Sci 2023; 13:1607. [PMID: 38002566 PMCID: PMC10670443 DOI: 10.3390/brainsci13111607] [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: 11/01/2023] [Revised: 11/15/2023] [Accepted: 11/17/2023] [Indexed: 11/26/2023] Open
Abstract
Diffuse axonal injury (DAI) is a significant feature of traumatic brain injury (TBI) across all injury severities and is driven by the primary mechanical insult and secondary biochemical injury phases. Axons comprise an outer cell membrane, the axolemma which is anchored to the cytoskeletal network with spectrin tetramers and actin rings. Neurofilaments act as space-filling structural polymers that surround the central core of microtubules, which facilitate axonal transport. TBI has differential effects on these cytoskeletal components, with axons in the same white matter tract showing a range of different cytoskeletal and axolemma alterations with different patterns of temporal evolution. These require different antibodies for detection in post-mortem tissue. Here, a comprehensive discussion of the evolution of axonal injury within different cytoskeletal elements is provided, alongside the most appropriate methods of detection and their temporal profiles. Accumulation of amyloid precursor protein (APP) as a result of disruption of axonal transport due to microtubule failure remains the most sensitive marker of axonal injury, both acutely and chronically. However, a subset of injured axons demonstrate different pathology, which cannot be detected via APP immunoreactivity, including degradation of spectrin and alterations in neurofilaments. Furthermore, recent work has highlighted the node of Ranvier and the axon initial segment as particularly vulnerable sites to axonal injury, with loss of sodium channels persisting beyond the acute phase post-injury in axons without APP pathology. Given the heterogenous response of axons to TBI, further characterization is required in the chronic phase to understand how axonal injury evolves temporally, which may help inform pharmacological interventions.
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Affiliation(s)
- Justin L Krieg
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide 5000, Australia
| | - Anna V Leonard
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide 5000, Australia
| | - Renée J Turner
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide 5000, Australia
| | - Frances Corrigan
- Translational Neuropathology Laboratory, School of Biomedicine, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide 5000, Australia
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5
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Maliha F, Adnan A. Mechanical Responses of a Single Myelin Layer: A Molecular Simulation Study. Biomolecules 2023; 13:1525. [PMID: 37892207 PMCID: PMC10605433 DOI: 10.3390/biom13101525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/06/2023] [Accepted: 10/12/2023] [Indexed: 10/29/2023] Open
Abstract
The myelin sheath provides insulation to the brain's neuron cells, which aids in signal transmission and communication with the body. Degenerated myelin hampers the connection between the glial cells, which are the front row responders during traumatic brain injury mitigation. Thus, the structural integrity of the myelin layer is critical for protecting the brain tissue from traumatic injury. At the molecular level, myelin consists of a lipid bilayer, myelin basic proteins (MBP), proteolipid proteins (PLP), water and ions. Structurally, the myelin sheath is formed by repeatedly wrapping forty or more myelin layers around an axon. Here, we have used molecular dynamic simulations to model and capture the tensile response of a single myelin layer. An openly available molecular dynamic solver, LAMMPS, was used to conduct the simulations. The interatomic potentials for the interacting atoms and molecules were defined using CHARMM force fields. Following a standard equilibration process, the molecular model was stretched uniaxially at a deformation rate of 5 Å/ps. We observed that, at around 10% applied strain, the myelin started to cohesively fail via flaw formation inside the bilayers. Further stretching led to a continued expansion of the defect inside the bilayer, both radially and transversely. This study provides the cellular-level mechanisms of myelin damage due to mechanical load.
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Affiliation(s)
| | - Ashfaq Adnan
- Department of Mechanical and Aerospace Engineering, The University of Texas at Arlington, Arlington, TX 76019, USA;
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6
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Zhang C, Ji S. Sex Differences in Axonal Dynamic Responses Under Realistic Tension Using Finite Element Models. J Neurotrauma 2023; 40:2217-2232. [PMID: 37335051 DOI: 10.1089/neu.2022.0512] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2023] Open
Abstract
Existing axonal finite element models do not consider sex morphological differences or the fidelity in dynamic input. To facilitate a systematic investigation into the micromechanics of diffuse axonal injury, we develop a parameterized modeling approach for automatic and efficient generation of sex-specific axonal models according to specified geometrical parameters. Baseline female and male axonal models in the corpus callosum with random microtubule (MT) gap configurations are generated for model calibration and evaluation. They are then used to simulate a realistic tensile loading consisting of both a loading and a recovery phase (to return to an initial undeformed state) generated from dynamic corpus callosum fiber strain in a real-world head impact simulation. We find that MT gaps and the dynamic recovery phase are both critical to successfully reproduce MT undulation as observed experimentally, which has not been reported before. This strengthens confidence in model dynamic responses. A statistical approach is further employed to aggregate axonal responses from a large sample of random MT gap configurations for both female and male axonal models (n = 10,000 each). We find that peak strains in MTs and the Ranvier node and associated neurofilament failures in female axons are substantially higher than those in male axons because there are fewer MTs in the former and also because of the random nature of MT gap locations. Despite limitations in various model assumptions as a result of limited experimental data currently available, these findings highlight the need to systematically characterize MT gap configurations and to ensure a realistic model input for axonal dynamic simulations. Finally, this study may offer fresh and improved insight into the biomechanical basis of sex differences in brain injury, and sets the stage for more systematic investigations at the microscale in the future, both numerically and experimentally.
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Affiliation(s)
- Chaokai Zhang
- Department of Biomedical Engineering and Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Songbai Ji
- Department of Biomedical Engineering and Worcester Polytechnic Institute, Worcester, Massachusetts, USA
- Department of Mechanical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
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7
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Ghose A, Pullarkat P. The role of mechanics in axonal stability and development. Semin Cell Dev Biol 2023; 140:22-34. [PMID: 35786351 PMCID: PMC7615100 DOI: 10.1016/j.semcdb.2022.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/05/2022] [Accepted: 06/13/2022] [Indexed: 01/28/2023]
Abstract
Much of the focus of neuronal cell biology has been devoted to growth cone guidance, synaptogenesis, synaptic activity, plasticity, etc. The axonal shaft too has received much attention, mainly for its astounding ability to transmit action potentials and the transport of material over long distances. For these functions, the axonal cytoskeleton and membrane have been often assumed to play static structural roles. Recent experiments have changed this view by revealing an ultrastructure much richer in features than previously perceived and one that seems to be maintained at a dynamic steady state. The role of mechanics in this is only beginning to be broadly appreciated and appears to involve passive and active modes of coupling different biopolymer filaments, filament turnover dynamics and membrane biophysics. Axons, being unique cellular processes in terms of high aspect ratios and often extreme lengths, also exhibit unique passive mechanical properties that might have evolved to stabilize them under mechanical stress. In this review, we summarize the experiments that have exposed some of these features. It is our view that axonal mechanics deserves much more attention not only due to its significance in the development and maintenance of the nervous system but also due to the susceptibility of axons to injury and neurodegeneration.
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Affiliation(s)
- Aurnab Ghose
- Indian Institute of Science Education and Research, Pune 411 008, India.
| | - Pramod Pullarkat
- Raman Research Institute, C. V. Raman Avenue, Bengaluru 560 080, India.
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8
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Wang LM, Kuhl E. Mechanics of axon growth and damage: A systematic review of computational models. Semin Cell Dev Biol 2023; 140:13-21. [PMID: 35474150 DOI: 10.1016/j.semcdb.2022.04.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 04/12/2022] [Accepted: 04/19/2022] [Indexed: 01/28/2023]
Abstract
Normal axon development depends on the action of mechanical forces both generated within the cytoskeleton and outside the cell, but forces of large magnitude or rate cause damage instead. Computational models aid scientists in studying the role of mechanical forces in axon growth and damage. These studies use simulations to evaluate how different sources of force generation within the cytoskeleton interact with each other to regulate axon elongation and retraction. Furthermore, mathematical models can help optimize externally applied tension to promote axon growth without causing damage. Finally, scientists also use simulations of axon damage to investigate how forces are distributed among different components of the axon and how the tissue surrounding an axon influences its susceptibility to injury. In this review, we discuss how computational studies complement experimental studies in the areas of axon growth, regeneration, and damage.
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Affiliation(s)
- Lucy M Wang
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Ellen Kuhl
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA.
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9
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Chai Z, Gu S, Lykotrafitis G. Dynamics of the axon plasma membrane skeleton. SOFT MATTER 2023; 19:2514-2528. [PMID: 36939651 DOI: 10.1039/d2sm01602h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
It was recently revealed via super-resolution microscopy experiments that the axon plasma membrane skeleton (APMS) comprises a series of periodically arranged azimuthal actin rings connected via longitudinal spectrin filaments forming an orthotropic network. The common perception is that APMS enhances structural stability of the axon but its impact on axon deformation is unknown. To investigate the response of the APMS to extension, we introduce a coarse-grain molecular dynamics model consisting of actin particles forming rings and chains of particles representing spectrin tetramers with repeats than can unfold. We observe that the shape of force-extension curve is initially linear and the force level depends on the extension rate. Even during the initial deformation stage, unfolding of spectrin repeats occurs, but the saw-tooth shape of the corresponding force-extension curve observed in the case of one spectrin tetramer does not appear in the case of the entire APMS. The reason is that spectrin unfolding is not synchronized across filaments during extension. If actin-spectrin associations remain intact, the force-extension response reaches a perfectly plastic region because of increased spectrin unfolding frequency. However, when actin-spectrin links dissociate, which can happen at moderate and high extension rates, APMS softens and the resistance force decreases linearly as the axon elongates until it reaches a point where the APMS is completely severed. Furthermore, when the ring-to-ring distance is maintained fixed under stretch, the resistance force relaxes exponentially as a function of time due to additional unfolding of spectrin tetramers following the Kelvin-Voigt representation of the Zener model.
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Affiliation(s)
- Zhaojie Chai
- Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269, USA.
| | - Shiju Gu
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut, USA
| | - George Lykotrafitis
- Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269, USA.
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut, USA
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10
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Pan X, Li J, Li W, Wang H, Durisic N, Li Z, Feng Y, Liu Y, Zhao CX, Wang T. Axons-on-a-chip for mimicking non-disruptive diffuse axonal injury underlying traumatic brain injury. LAB ON A CHIP 2022; 22:4541-4555. [PMID: 36318066 DOI: 10.1039/d2lc00730d] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Diffuse axonal injury (DAI) is the most severe pathological feature of traumatic brain injury (TBI). However, how primary axonal injury is induced by transient mechanical impacts remains unknown, mainly due to the low temporal and spatial resolution of medical imaging approaches. Here we established an axon-on-a-chip (AoC) model for mimicking DAI and monitoring instant cellular responses. Integrating computational fluid dynamics and microfluidic techniques, DAI was induced by injecting a precisely controlled micro-flux in the transverse direction. The clear correlation between the flow speed of injecting flux and the severity of DAI was elucidated. We next used the AoC to investigate the instant intracellular responses underlying DAI and found that the dynamic formation of focal axonal swellings (FAS) accompanied by Ca2+ surge occurs during the flux. Surprisingly, periodic axonal cytoskeleton disruption also occurs rapidly after the flux. These instant injury responses are spatially restricted to the fluxed axon, not affecting the overall viability of the neuron in the acute stage. Compatible with high-resolution live microscopy, the AoC provides a versatile system to identify early mechanisms underlying DAI, offering a platform for screening effective treatments to alleviate TBI.
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Affiliation(s)
- Xiaorong Pan
- The Brain Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Jie Li
- Division of Chemistry and Physical Biology, School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Wei Li
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Haofei Wang
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Nela Durisic
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Zhenyu Li
- The Brain Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Yu Feng
- The Brain Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
| | - Yifan Liu
- Division of Chemistry and Physical Biology, School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Chun-Xia Zhao
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
- School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, SA 5005, Australia.
| | - Tong Wang
- The Brain Center, School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
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11
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Unraveling axonal mechanisms of traumatic brain injury. Acta Neuropathol Commun 2022; 10:140. [PMID: 36131329 PMCID: PMC9494812 DOI: 10.1186/s40478-022-01414-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 07/18/2022] [Indexed: 11/28/2022] Open
Abstract
Axonal swellings (AS) are one of the neuropathological hallmark of axonal injury in several disorders from trauma to neurodegeneration. Current evidence proposes a role of perturbed Ca2+ homeostasis in AS formation, involving impaired axonal transport and focal distension of the axons. Mechanisms of AS formation, in particular moments following injury, however, remain unknown. Here we show that AS form independently from intra-axonal Ca2+ changes, which are required primarily for the persistence of AS in time. We further show that the majority of axonal proteins undergoing de/phosphorylation immediately following injury belong to the cytoskeleton. This correlates with an increase in the distance of the actin/spectrin periodic rings and with microtubule tracks remodeling within AS. Observed cytoskeletal rearrangements support axonal transport without major interruptions. Our results demonstrate that the earliest axonal response to injury consists in physiological adaptations of axonal structure to preserve function rather than in immediate pathological events signaling axonal destruction.
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12
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Leterrier C, Pullarkat PA. Mechanical role of the submembrane spectrin scaffold in red blood cells and neurons. J Cell Sci 2022; 135:276327. [PMID: 35972759 DOI: 10.1242/jcs.259356] [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] [Indexed: 11/20/2022] Open
Abstract
Spectrins are large, evolutionarily well-conserved proteins that form highly organized scaffolds on the inner surface of eukaryotic cells. Their organization in different cell types or cellular compartments helps cells withstand mechanical challenges with unique strategies depending on the cell type. This Review discusses our understanding of the mechanical properties of spectrins, their very distinct organization in red blood cells and neurons as two examples, and the contribution of the scaffolds they form to the mechanical properties of these cells.
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Affiliation(s)
- Christophe Leterrier
- Aix Marseille Université, CNRS, INP UMR 7051, NeuroCyto, Marseille 13005, France
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13
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Bigler ED, Allder S. Earliest Marker of Brain Injury in Repetitive Sports-Related Concussion: Canary in the Midline? Neurology 2021; 97:567-569. [PMID: 34433677 DOI: 10.1212/wnl.0000000000012589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 07/23/2021] [Indexed: 11/15/2022] Open
Affiliation(s)
- Erin D Bigler
- From the Departments of Neurology and Psychiatry (E.D.B.), University of Utah, Salt Lake City; Department of Psychology and Neuroscience Center (E.D.B.), Brigham Young University, Provo, UT; Department of Neurology (E.D.B.), University of California-Davis, Sacramento; and Re:Cognition Health (S.A.), London, UK.
| | - Steven Allder
- From the Departments of Neurology and Psychiatry (E.D.B.), University of Utah, Salt Lake City; Department of Psychology and Neuroscience Center (E.D.B.), Brigham Young University, Provo, UT; Department of Neurology (E.D.B.), University of California-Davis, Sacramento; and Re:Cognition Health (S.A.), London, UK
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