1
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Yang Q, Vazquez AL, Cui XT. Revealing in vivo cellular mechanisms of cerebral microbleeds on neurons and microglia across cortical layers. iScience 2024; 27:109371. [PMID: 38510113 PMCID: PMC10951986 DOI: 10.1016/j.isci.2024.109371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 12/28/2023] [Accepted: 02/26/2024] [Indexed: 03/22/2024] Open
Abstract
Cerebral microbleeds (CMBs) are associated with higher risk for various neurological diseases including stroke, dementia, and Alzheimer's disease. However, the understanding of cellular pathology of CMBs, particularly in deep brain regions, remains limited. Utilizing two-photon microscopy and microprism implantation, we longitudinally imaged the impact of CMBs on neuronal and microglial activities across cortical depths in awake mice. A temporary decline in spontaneous neuronal activity occurred throughout cortical layers, followed by recovery within a week. However, significant changes of neuron-neuron activity correlations persisted for weeks. Moreover, microglial contact with neuron soma significantly increased post-microbleeds, indicating an important modulatory role of microglia. Notably, microglial contact, negatively correlated with neuronal firing rate in normal conditions, became uncorrelated after microbleeds, suggesting a decreased neuron-microglia inhibition. These findings reveal chronic alterations in cortical neuronal networks and microglial-neuronal interactions across cortical depths, shedding light on the pathology of CMBs.
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Affiliation(s)
- Qianru Yang
- Department of Neurosurgery, Stanford University, Palo Alto, CA, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, USA
| | - Alberto L. Vazquez
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, USA
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - X. Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Center for Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, USA
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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2
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Bancelin S, Mercier L, Roos J, Belkadi M, Pfeiffer T, Kim SK, Nägerl UV. Imaging dendritic spines in the hippocampus of a living mouse by 3D-stimulated emission depletion microscopy. NEUROPHOTONICS 2023; 10:044402. [PMID: 37215638 PMCID: PMC10197143 DOI: 10.1117/1.nph.10.4.044402] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/31/2023] [Accepted: 04/14/2023] [Indexed: 05/24/2023]
Abstract
Significance Stimulated emission depletion (STED) microscopy has been used to address a wide range of neurobiological questions in optically well-accessible samples, such as cell culture or brain slices. However, the application of STED to deeply embedded structures in the brain of living animals remains technically challenging. Aim In previous work, we established chronic STED imaging in the hippocampus in vivo but the gain in spatial resolution was restricted to the lateral plane. In our study, we report on extending the gain in STED resolution into the optical axis to visualize dendritic spines in the hippocampus in vivo. Approach Our approach is based on a spatial light modulator to shape the focal STED light intensity in all three dimensions and a conically shaped window that is compatible with an objective that has a long working distance and a high numerical aperture. We corrected distortions of the laser wavefront to optimize the shape of the bottle beam of the STED laser. Results We show how the new window design improves the STED point spread function and the spatial resolution using nanobeads. We then demonstrate the beneficial effects for 3D-STED microscopy of dendritic spines, visualized with an unprecedented level of detail in the hippocampus of a living mouse. Conclusions We present a methodology to improve the axial resolution for STED microscopy in the deeply embedded hippocampus in vivo, facilitating longitudinal studies of neuroanatomical plasticity at the nanoscale in a wide range of (patho-)physiological contexts.
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Affiliation(s)
- Stéphane Bancelin
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
| | - Luc Mercier
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
| | - Johannes Roos
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
| | - Mohamed Belkadi
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
| | - Thomas Pfeiffer
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
| | - Sun Kwang Kim
- Kyung Hee University, Graduate School, Department of Science in Korean Medicine, Seoul, Republic of Korea
| | - U. Valentin Nägerl
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
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3
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Grabarz AM, Ośmiałowski B. Benchmarking Density Functional Approximations for Excited-State Properties of Fluorescent Dyes. Molecules 2021; 26:7434. [PMID: 34946515 PMCID: PMC8703901 DOI: 10.3390/molecules26247434] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/28/2021] [Accepted: 12/04/2021] [Indexed: 12/05/2022] Open
Abstract
This study presents an extensive analysis of the predictive power of time-dependent density functional theory in determining the excited-state properties of two groups of important fluorescent dyes, difluoroboranes and hydroxyphenylimidazo[1,2-a]pyridine derivatives. To ensure statistically meaningful results, the data set is comprised of 85 molecules manifesting diverse photophysical properties. The vertical excitation energies and dipole moments (in the electronic ground and excited states) of the aforementioned dyes were determined using the RI-CC2 method (reference) and with 18 density functional approximations (DFA). The set encompasses DFAs with varying amounts of exact exchange energy (EEX): from 0% (e.g., SVWN, BLYP), through a medium (e.g., TPSSh, B3LYP), up to a major contribution of EEX (e.g., BMK, MN15). It also includes range-separated hybrids (CAM-B3LYP, LC-BLYP). Similar error profiles of vertical energy were obtained for both dye groups, although the errors related to hydroxyphenylimidazopiridines are significantly larger. Overall, functionals including 40-55% of EEX (SOGGA11-X, BMK, M06-2X) ensure satisfactory agreement with the reference vertical excitation energies obtained using the RI-CC2 method; however, MN15 significantly outperforms them, providing a mean absolute error of merely 0.04 eV together with a very high correlation coefficient (R2 = 0.98). Within the investigated set of functionals, there is no single functional that would equally accurately determine ground- and excited-state dipole moments of difluoroboranes and hydroxyphenylimidazopiridine derivatives. Depending on the chosen set of dyes, the most accurate μGS predictions were delivered by MN15 incorporating a major EEX contribution (difluoroboranes) and by PBE0 containing a minor EEX fraction (hydroxyphenylimidazopiridines). Reverse trends are observed for μES, i.e., for difluoroboranes the best results were obtained with functionals including a minor fraction of EEX, specifically PBE0, while in the case of hydroxyphenylimidazopiridines, much more accurate predictions were provided by functionals incorporating a major EEX contribution (BMK, MN15).
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Affiliation(s)
- Anna M. Grabarz
- Faculty of Chemistry, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, PL-50370 Wrocław, Poland
| | - Borys Ośmiałowski
- Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 7, PL-87100 Toruń, Poland;
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4
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Conti E, Piccardi B, Sodero A, Tudisco L, Lombardo I, Fainardi E, Nencini P, Sarti C, Allegra Mascaro AL, Baldereschi M. Translational Stroke Research Review: Using the Mouse to Model Human Futile Recanalization and Reperfusion Injury in Ischemic Brain Tissue. Cells 2021; 10:3308. [PMID: 34943816 PMCID: PMC8699609 DOI: 10.3390/cells10123308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 11/17/2021] [Accepted: 11/19/2021] [Indexed: 12/20/2022] Open
Abstract
The approach to reperfusion therapies in stroke patients is rapidly evolving, but there is still no explanation why a substantial proportion of patients have a poor clinical prognosis despite successful flow restoration. This issue of futile recanalization is explained here by three clinical cases, which, despite complete recanalization, have very different outcomes. Preclinical research is particularly suited to characterize the highly dynamic changes in acute ischemic stroke and identify potential treatment targets useful for clinical translation. This review surveys the efforts taken so far to achieve mouse models capable of investigating the neurovascular underpinnings of futile recanalization. We highlight the translational potential of targeting tissue reperfusion in fully recanalized mouse models and of investigating the underlying pathophysiological mechanisms from subcellular to tissue scale. We suggest that stroke preclinical research should increasingly drive forward a continuous and circular dialogue with clinical research. When the preclinical and the clinical stroke research are consistent, translational success will follow.
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Affiliation(s)
- Emilia Conti
- Neuroscience Institute, National Research Council, Via G. Moruzzi 1, 56124 Pisa, Italy; (E.C.); (A.L.A.M.)
- European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy
| | - Benedetta Piccardi
- Neurofarba Department, University of Florence, Via G. Pieraccini 6, 50139 Florence, Italy; (A.S.); (L.T.); (C.S.)
| | - Alessandro Sodero
- Neurofarba Department, University of Florence, Via G. Pieraccini 6, 50139 Florence, Italy; (A.S.); (L.T.); (C.S.)
| | - Laura Tudisco
- Neurofarba Department, University of Florence, Via G. Pieraccini 6, 50139 Florence, Italy; (A.S.); (L.T.); (C.S.)
| | - Ivano Lombardo
- Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence, Italy; (I.L.); (E.F.)
| | - Enrico Fainardi
- Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence, Italy; (I.L.); (E.F.)
| | - Patrizia Nencini
- Stroke Unit, Careggi University Hospital, Largo Brambilla 3, 50134 Florence, Italy;
| | - Cristina Sarti
- Neurofarba Department, University of Florence, Via G. Pieraccini 6, 50139 Florence, Italy; (A.S.); (L.T.); (C.S.)
| | - Anna Letizia Allegra Mascaro
- Neuroscience Institute, National Research Council, Via G. Moruzzi 1, 56124 Pisa, Italy; (E.C.); (A.L.A.M.)
- European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy
| | - Marzia Baldereschi
- Neuroscience Institute, National Research Council, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy;
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5
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Vollmer KM, Doncheck EM, Grant RI, Winston KT, Romanova EV, Bowen CW, Siegler PN, Green LM, Bobadilla AC, Trujillo-Pisanty I, Kalivas PW, Otis JM. A Novel Assay Allowing Drug Self-Administration, Extinction, and Reinstatement Testing in Head-Restrained Mice. Front Behav Neurosci 2021; 15:744715. [PMID: 34776891 PMCID: PMC8585999 DOI: 10.3389/fnbeh.2021.744715] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 09/30/2021] [Indexed: 01/15/2023] Open
Abstract
Multiphoton microscopy is one of several new technologies providing unprecedented insight into the activity dynamics and function of neural circuits. Unfortunately, some of these technologies require experimentation in head-restrained animals, limiting the behavioral repertoire that can be integrated and studied. This issue is especially evident in drug addiction research, as no laboratories have coupled multiphoton microscopy with simultaneous intravenous drug self-administration, a behavioral paradigm that has predictive validity for treatment outcomes and abuse liability. Here, we describe a new experimental assay wherein head-restrained mice will press an active lever, but not inactive lever, for intravenous delivery of heroin or cocaine. Similar to freely moving animals, we find that lever pressing is suppressed through daily extinction training and subsequently reinstated through the presentation of relapse-provoking triggers (drug-associative cues, the drug itself, and stressors). Finally, we show that head-restrained mice will show similar patterns of behavior for oral delivery of a sucrose reward, a common control used for drug self-administration experiments. Overall, these data demonstrate the feasibility of combining drug self-administration experiments with technologies that require head-restraint, such as multiphoton imaging. The assay described could be replicated by interested labs with readily available materials to aid in identifying the neural underpinnings of substance use disorder.
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Affiliation(s)
- Kelsey M Vollmer
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - Elizabeth M Doncheck
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - Roger I Grant
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - Kion T Winston
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - Elizaveta V Romanova
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - Christopher W Bowen
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - Preston N Siegler
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - Lisa M Green
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | | | | | - Peter W Kalivas
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - James M Otis
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States.,Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States
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6
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Canty AJ, Jackson JS, Huang L, Trabalza A, Bass C, Little G, Tortora M, Khan S, De Paola V. In vivo imaging of injured cortical axons reveals a rapid onset form of Wallerian degeneration. BMC Biol 2020; 18:170. [PMID: 33208154 PMCID: PMC7677840 DOI: 10.1186/s12915-020-00869-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 09/16/2020] [Indexed: 12/22/2022] Open
Abstract
Background Despite the widespread occurrence of axon and synaptic loss in the injured and diseased nervous system, the cellular and molecular mechanisms of these key degenerative processes remain incompletely understood. Wallerian degeneration (WD) is a tightly regulated form of axon loss after injury, which has been intensively studied in large myelinated fibre tracts of the spinal cord, optic nerve and peripheral nervous system (PNS). Fewer studies, however, have focused on WD in the complex neuronal circuits of the mammalian brain, and these were mainly based on conventional endpoint histological methods. Post-mortem analysis, however, cannot capture the exact sequence of events nor can it evaluate the influence of elaborated arborisation and synaptic architecture on the degeneration process, due to the non-synchronous and variable nature of WD across individual axons. Results To gain a comprehensive picture of the spatiotemporal dynamics and synaptic mechanisms of WD in the nervous system, we identify the factors that regulate WD within the mouse cerebral cortex. We combined single-axon-resolution multiphoton imaging with laser microsurgery through a cranial window and a fluorescent membrane reporter. Longitudinal imaging of > 150 individually injured excitatory cortical axons revealed a threshold length below which injured axons consistently underwent a rapid-onset form of WD (roWD). roWD started on average 20 times earlier and was executed 3 times slower than WD described in other regions of the nervous system. Cortical axon WD and roWD were dependent on synaptic density, but independent of axon complexity. Finally, pharmacological and genetic manipulations showed that a nicotinamide adenine dinucleotide (NAD+)-dependent pathway could delay cortical roWD independent of transcription in the damaged neurons, demonstrating further conservation of the molecular mechanisms controlling WD in different areas of the mammalian nervous system. Conclusions Our data illustrate how in vivo time-lapse imaging can provide new insights into the spatiotemporal dynamics and synaptic mechanisms of axon loss and assess therapeutic interventions in the injured mammalian brain.
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Affiliation(s)
- Alison Jane Canty
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, Australia.
| | - Johanna Sara Jackson
- Dementia Research Institute at Imperial College, Department of Brain Sciences, Imperial College London, London, W12 0NN, UK
| | - Lieven Huang
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Antonio Trabalza
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Cher Bass
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Graham Little
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Maria Tortora
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Shabana Khan
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK
| | - Vincenzo De Paola
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, London, W12 0NN, UK. .,Medical Research Council London Institute of Medical Sciences, London, W12 0NN, UK.
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7
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Cangalaya C, Stoyanov S, Fischer KD, Dityatev A. Light-induced engagement of microglia to focally remodel synapses in the adult brain. eLife 2020; 9:e58435. [PMID: 32808923 PMCID: PMC7470825 DOI: 10.7554/elife.58435] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/18/2020] [Indexed: 12/18/2022] Open
Abstract
Microglia continuously monitor synapses, but active synaptic remodeling by microglia in mature healthy brains is rarely directly observed. We performed targeted photoablation of single synapses in mature transgenic mice expressing fluorescent labels in neurons and microglia. The photodamage focally increased the duration of microglia-neuron contacts, and dramatically exacerbated both the turnover of dendritic spines and presynaptic boutons as well as the generation of new filopodia originating from spine heads or boutons. The results of microglia depletion confirmed that elevated spine turnover and the generation of presynaptic filopodia are microglia-dependent processes.
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Affiliation(s)
- Carla Cangalaya
- ESF International Graduate School on Analysis, Imaging and Modelling of Neuronal and Inflammatory ProcessesMagdeburgGermany
- Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical FacultyMagdeburgGermany
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE)MagdeburgGermany
| | - Stoyan Stoyanov
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE)MagdeburgGermany
| | - Klaus-Dieter Fischer
- Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical FacultyMagdeburgGermany
| | - Alexander Dityatev
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE)MagdeburgGermany
- Medical Faculty, Otto-von-Guericke UniversityMagdeburgGermany
- Center for Behavioral Brain Sciences (CBBS)MagdeburgGermany
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8
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In vivo two-photon microscopic observation and ablation in deeper brain regions realized by modifications of excitation beam diameter and immersion liquid. PLoS One 2020; 15:e0237230. [PMID: 32764808 PMCID: PMC7413496 DOI: 10.1371/journal.pone.0237230] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 07/21/2020] [Indexed: 02/06/2023] Open
Abstract
In vivo two-photon microscopy utilizing a nonlinear optical process enables, in living mouse brains, not only the visualization of morphologies and functions of neural networks in deep regions but also their optical manipulation at targeted sites with high spatial precision. Because the two-photon excitation efficiency is proportional to the square of the photon density of the excitation laser light at the focal position, optical aberrations induced by specimens mainly limit the maximum depth of observations or that of manipulations in the microscopy. To increase the two-photon excitation efficiency, we developed a method for evaluating the focal volume in living mouse brains. With this method, we modified the beam diameter of the excitation laser light and the value of the refractive index in the immersion liquid to maximize the excitation photon density at the focal position. These two modifications allowed the successful visualization of the finer structures of hippocampal CA1 neurons, as well as the intracellular calcium dynamics in cortical layer V astrocytes, even with our conventional two-photon microscopy system. Furthermore, it enabled focal laser ablation dissection of both single apical and single basal dendrites of cortical layer V pyramidal neurons. These simple modifications would enable us to investigate the contributions of single cells or single dendrites to the functions of local cortical networks.
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9
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Recurrent interactions in local cortical circuits. Nature 2020; 579:256-259. [PMID: 32132709 DOI: 10.1038/s41586-020-2062-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 01/14/2020] [Indexed: 12/26/2022]
Abstract
Most cortical synapses are local and excitatory. Local recurrent circuits could implement amplification, allowing pattern completion and other computations1-4. Cortical circuits contain subnetworks that consist of neurons with similar receptive fields and increased connectivity relative to the network average5,6. Cortical neurons that encode different types of information are spatially intermingled and distributed over large brain volumes5-7, and this complexity has hindered attempts to probe the function of these subnetworks by perturbing them individually8. Here we use computational modelling, optical recordings and manipulations to probe the function of recurrent coupling in layer 2/3 of the mouse vibrissal somatosensory cortex during active tactile discrimination. A neural circuit model of layer 2/3 revealed that recurrent excitation enhances sensory signals by amplification, but only for subnetworks with increased connectivity. Model networks with high amplification were sensitive to damage: loss of a few members of the subnetwork degraded stimulus encoding. We tested this prediction by mapping neuronal selectivity7 and photoablating9,10 neurons with specific selectivity. Ablation of a small proportion of layer 2/3 neurons (10-20, less than 5% of the total) representing touch markedly reduced responses in the spared touch representation, but not in other representations. Ablations most strongly affected neurons with stimulus responses that were similar to those of the ablated population, which is also consistent with network models. Recurrence among cortical neurons with similar selectivity therefore drives input-specific amplification during behaviour.
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10
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Astrocytic endfeet re-cover blood vessels after removal by laser ablation. Sci Rep 2019; 9:1263. [PMID: 30718555 PMCID: PMC6362239 DOI: 10.1038/s41598-018-37419-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 12/03/2018] [Indexed: 11/08/2022] Open
Abstract
The astrocyte, one of the glial cells, plays many functional roles. These include provision of nutrients from blood vessels to neurons, supply of neurotransmitters and support of blood-brain barrier (BBB) integrity. Astrocytes are known to support the integrity of BBB through maintenance of the tight junction between endothelial cells of blood vessels. However, evidence of its direct contribution to BBB is lacking owing to technical limitations. In this study, astrocytic endfeet covering blood vessels were removed by the laser ablation method with two photon laser scanning microscopy in in vivo mouse brain, and the re-covering of blood vessels with the astrocytic endfeet was observed in about half of the cases. Blood vessels kept their integrity without astrocytic endfoot covers: leakage of plasma marker dyes, Evans Blue or dextran-conjugated fluorescein, was not observed from stripped blood vessels, while ablation of vascular walls induced extravasation of Evans Blue. These results suggest that the astrocytic endfeet covering blood vessels do not contribute to the immediate BBB barrier.
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11
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Hierro-Bujalance C, Bacskai BJ, Garcia-Alloza M. In Vivo Imaging of Microglia With Multiphoton Microscopy. Front Aging Neurosci 2018; 10:218. [PMID: 30072888 PMCID: PMC6060250 DOI: 10.3389/fnagi.2018.00218] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 06/26/2018] [Indexed: 01/04/2023] Open
Abstract
Neuroimaging has become an unparalleled tool to understand the central nervous system (CNS) anatomy, physiology and neurological diseases. While an altered immune function and microglia hyperactivation are common neuropathological features for many CNS disorders and neurodegenerative diseases, direct assessment of the role of microglial cells remains a challenging task. Non-invasive neuroimaging techniques, including magnetic resonance imaging (MRI), positron emission tomography (PET) and single positron emission computed tomography (SPECT) are widely used for human clinical applications, and a variety of ligands are available to detect neuroinflammation. In animal models, intravital imaging has been largely used, and minimally invasive multiphoton microcopy (MPM) provides high resolution detection of single microglia cells, longitudinally, in living brain. In this study, we review in vivo real-time MPM approaches to assess microglia in preclinical studies, including individual cell responses in surveillance, support, protection and restoration of brain tissue integrity, synapse formation, homeostasis, as well as in different pathological situations. We focus on in vivo studies that assess the role of microglia in mouse models of Alzheimer’s disease (AD), analyzing microglial motility and recruitment, as well as the role of microglia in anti-amyloid-β treatment, as a key therapeutic approach to treat AD. Altogether, MPM provides a high contrast and high spatial resolution approach to follow microglia chronically in vivo in complex models, supporting MPM as a powerful tool for deep intravital tissue imaging.
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Affiliation(s)
- Carmen Hierro-Bujalance
- Division of Physiology, School of Medicine, Instituto de Investigación e Innovación en Ciencias Biomedicas de la Provincia de Cadiz (INiBICA), Universidad de Cádiz, Cádiz, Spain
| | - Brian J Bacskai
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Harvard University, Boston, MA, United States
| | - Monica Garcia-Alloza
- Division of Physiology, School of Medicine, Instituto de Investigación e Innovación en Ciencias Biomedicas de la Provincia de Cadiz (INiBICA), Universidad de Cádiz, Cádiz, Spain
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12
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Zohrabi M, Cormack RH, Mccullough C, Supekar OD, Gibson EA, Bright VM, Gopinath JT. Numerical analysis of wavefront aberration correction using multielectrode electrowetting-based devices. OPTICS EXPRESS 2017; 25:31451-31461. [PMID: 29245820 PMCID: PMC5941994 DOI: 10.1364/oe.25.031451] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 11/15/2017] [Accepted: 11/16/2017] [Indexed: 05/25/2023]
Abstract
We present numerical simulations of multielectrode electrowetting devices used in a novel optical design to correct wavefront aberration. Our optical system consists of two multielectrode devices, preceded by a single fixed lens. The multielectrode elements function as adaptive optical devices that can be used to correct aberrations inherent in many imaging setups, biological samples, and the atmosphere. We are able to accurately simulate the liquid-liquid interface shape using computational fluid dynamics. Ray tracing analysis of these surfaces shows clear evidence of aberration correction. To demonstrate the strength of our design, we studied three different input aberrations mixtures that include astigmatism, coma, trefoil, and additional higher order aberration terms, with amplitudes as large as one wave at 633 nm.
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Affiliation(s)
- Mo Zohrabi
- Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, CO 80309,
USA
| | - Robert H. Cormack
- Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, CO 80309,
USA
| | - Connor Mccullough
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO 80045,
USA
| | - Omkar D. Supekar
- Department of Mechanical Engineering, University of Colorado Boulder, CO 80309,
USA
| | - Emily A. Gibson
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO 80045,
USA
| | - Victor M. Bright
- Department of Mechanical Engineering, University of Colorado Boulder, CO 80309,
USA
| | - Juliet T. Gopinath
- Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, CO 80309,
USA
- Department of Physics, University of Colorado, Boulder, CO 80309,
USA
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Zhao Z, Chen S, Luo Y, Li J, Badea S, Ren C, Wu W. Time-lapse changes of in vivo injured neuronal substructures in the central nervous system after low energy two-photon nanosurgery. Neural Regen Res 2017; 12:751-756. [PMID: 28616030 PMCID: PMC5461611 DOI: 10.4103/1673-5374.206644] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
There is currently very little research regarding the dynamics of the subcellular degenerative events that occur in the central nervous system in response to injury. To date, multi-photon excitation has been primarily used for imaging applications; however, it has been recently used to selectively disrupt neural structures in living animals. However, understanding the complicated processes and the essential underlying molecular pathways involved in these dynamic events is necessary for studying the underlying process that promotes neuronal regeneration. In this study, we introduced a novel method allowing in vivo use of low energy (less than 30 mW) two-photon nanosurgery to selectively disrupt individual dendrites, axons, and dendritic spines in the murine brain and spinal cord to accurately monitor the time-lapse changes in the injured neuronal structures. Individual axons, dendrites, and dendritic spines in the brain and spinal cord were successfully ablated and in vivo imaging revealed the time-lapse alterations in these structures in response to the two-photon nanosurgery induced lesion. The energy (less than 30 mW) used in this study was very low and caused no observable additional damage in the neuronal sub-structures that occur frequently, especially in dendritic spines, with current commonly used methods using high energy levels. In addition, our approach includes the option of monitoring the time-varying dynamics to control the degree of lesion. The method presented here may be used to provide new insight into the growth of axons and dendrites in response to acute injury.
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Affiliation(s)
- Zhikai Zhao
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China
| | - Shuangxi Chen
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China
| | - Yunhao Luo
- School of Biomedical Sciences, Division of Anatomy, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Jing Li
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China
| | - Smaranda Badea
- School of Biomedical Sciences, Division of Anatomy, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Chaoran Ren
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China
| | - Wutian Wu
- Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China.,School of Biomedical Sciences, Division of Anatomy, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China.,Guangdong Engineering Research Center of Stem Cell Storage and Clinical Application, Saliai Stem Cell Science and Technology, Guangzhou, Guangdong Province, China.,State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
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14
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Targeted pruning of a neuron's dendritic tree via femtosecond laser dendrotomy. Sci Rep 2016; 6:19078. [PMID: 26739126 PMCID: PMC4703956 DOI: 10.1038/srep19078] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 12/04/2015] [Indexed: 12/25/2022] Open
Abstract
Neurons are classified according to action potential firing in response to current injection. While such firing patterns are shaped by the composition and distribution of ion channels, modelling studies suggest that the geometry of dendritic branches also influences temporal firing patterns. Verifying this link is crucial to understanding how neurons transform their inputs to output but has so far been technically challenging. Here, we investigate branching-dependent firing by pruning the dendritic tree of pyramidal neurons. We use a focused ultrafast laser to achieve highly localized and minimally invasive cutting of dendrites, thus keeping the rest of the dendritic tree intact and the neuron functional. We verify successful dendrotomy via two-photon uncaging of neurotransmitters before and after dendrotomy at sites around the cut region and via biocytin staining. Our results show that significantly altering the dendritic arborisation, such as by severing the apical trunk, enhances excitability in layer V cortical pyramidal neurons as predicted by simulations. This method may be applied to the analysis of specific relationships between dendritic structure and neuronal function. The capacity to dynamically manipulate dendritic topology or isolate inputs from various dendritic domains can provide a fresh perspective on the roles they play in shaping neuronal output.
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Selfridge A, Hyun N, Chiang CC, Reyna SM, Weissmiller AM, Shi LZ, Preece D, Mobley WC, Berns MW. Rat embryonic hippocampus and induced pluripotent stem cell derived cultured neurons recover from laser-induced subaxotomy. NEUROPHOTONICS 2015; 2:015006. [PMID: 26157985 PMCID: PMC4487718 DOI: 10.1117/1.nph.2.1.015006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 01/12/2015] [Indexed: 06/04/2023]
Abstract
Axonal injury and stress have long been thought to play a pathogenic role in a variety of neurodegenerative diseases. However, a model for studying single-cell axonal injury in mammalian cells and the processes of repair has not been established. The purpose of this study was to examine the response of neuronal growth cones to laser-induced axonal damage in cultures of embryonic rat hippocampal neurons and induced pluripotent stem cell (iPSC) derived human neurons. A 532-nm pulsed [Formula: see text] picosecond laser was focused to a diffraction limited spot at a precise location on an axon using a laser energy/power that did not rupture the cell membrane (subaxotomy). Subsequent time series images were taken to follow axonal recovery and growth cone dynamics. After laser subaxotomy, axons thinned at the damage site and initiated a dynamic cytoskeletal remodeling process to restore axonal thickness. The growth cone was observed to play a role in the repair process in both hippocampal and iPSC-derived neurons. Immunofluorescence staining confirmed structural tubulin damage and revealed initial phases of actin-based cytoskeletal remodeling at the damage site. The results of this study indicate that there is a repeatable and cross-species repair response of axons and growth cones after laser-induced damage.
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Affiliation(s)
- Aaron Selfridge
- University of California, San Diego, Department of Bioengineering, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Nicholas Hyun
- University of California, San Diego, Department of Bioengineering, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Chai-Chun Chiang
- University of California, San Diego, Department of Neurosciences, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Sol M. Reyna
- University of California, San Diego, Department of Biomedical Sciences, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - April M. Weissmiller
- University of California, San Diego, Department of Neurosciences, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Linda Z. Shi
- University of California, San Diego, Institute of Engineering in Medicine, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Daryl Preece
- University of California, San Diego, Department of NanoEngineering, 9500 Gilman Drive La Jolla, California 92093, United States
| | - William C. Mobley
- University of California, San Diego, Department of Neurosciences, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Michael W. Berns
- University of California, San Diego, Department of Bioengineering, 9500 Gilman Drive, La Jolla, California 92093, United States
- University of California, San Diego, Institute of Engineering in Medicine, 9500 Gilman Drive, La Jolla, California 92093, United States
- University of California, Irvine, Beckman Laser Institute, 1002 Health Sciences Road, Irvine, California 92612, United States
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Ferrantini C, Coppini R, Sacconi L, Tosi B, Zhang ML, Wang GL, de Vries E, Hoppenbrouwers E, Pavone F, Cerbai E, Tesi C, Poggesi C, ter Keurs HEDJ. Impact of detubulation on force and kinetics of cardiac muscle contraction. ACTA ACUST UNITED AC 2014; 143:783-97. [PMID: 24863933 PMCID: PMC4035744 DOI: 10.1085/jgp.201311125] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
T-tubule uncoupling from the plasma membrane leads to myocardial contractile abnormalities. Action potential–driven Ca2+ currents from the transverse tubules (t-tubules) trigger synchronous Ca2+ release from the sarcoplasmic reticulum of cardiomyocytes. Loss of t-tubules has been reported in cardiac diseases, including heart failure, but the effect of uncoupling t-tubules from the sarcolemma on cardiac muscle mechanics remains largely unknown. We dissected intact rat right ventricular trabeculae and compared force, sarcomere length, and intracellular Ca2+ in control trabeculae with trabeculae in which the t-tubules were uncoupled from the plasma membrane by formamide-induced osmotic shock (detubulation). We verified disconnection of a consistent fraction of t-tubules from the sarcolemma by two-photon fluorescence imaging of FM4-64–labeled membranes and by the absence of tubular action potential, which was recorded by random access multiphoton microscopy in combination with a voltage-sensitive dye (Di-4-AN(F)EPPTEA). Detubulation reduced the amplitude and prolonged the duration of Ca2+ transients, leading to slower kinetics of force generation and relaxation and reduced twitch tension (1 Hz, 30°C, 1.5 mM [Ca2+]o). No mechanical changes were observed in rat left atrial trabeculae after formamide shock, consistent with the lack of t-tubules in rodent atrial myocytes. Detubulation diminished the rate-dependent increase of Ca2+-transient amplitude and twitch force. However, maximal twitch tension at high [Ca2+]o or in post-rest potentiated beats was unaffected, although contraction kinetics were slower. The ryanodine receptor (RyR)2 Ca-sensitizing agent caffeine (200 µM), which increases the velocity of transverse Ca2+ release propagation in detubulated cardiomyocytes, rescued the depressed contractile force and the slower twitch kinetics of detubulated trabeculae, with negligible effects in controls. We conclude that partial loss of t-tubules leads to myocardial contractile abnormalities that can be rescued by enhancing and accelerating the propagation of Ca2+-induced Ca2+ release to orphan RyR2 clusters.
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Affiliation(s)
- Cecilia Ferrantini
- Center of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, ItalyCenter of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, Italy
| | - Raffaele Coppini
- Center of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, ItalyCenter of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, ItalyCenter of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, Italy
| | - Leonardo Sacconi
- Center of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, Italy National Institute of Optics, National Research Council, 50019 Sesto Fiorentino, Italy
| | - Benedetta Tosi
- Center of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, ItalyCenter of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, Italy
| | - Mei Luo Zhang
- Department of Cardiac Sciences of the Libin Institute at the Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Guo Liang Wang
- Department of Cardiac Sciences of the Libin Institute at the Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Ewout de Vries
- Department of Cardiac Sciences of the Libin Institute at the Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Ernst Hoppenbrouwers
- Department of Cardiac Sciences of the Libin Institute at the Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Francesco Pavone
- Center of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, ItalyCenter of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, Italy National Institute of Optics, National Research Council, 50019 Sesto Fiorentino, Italy
| | - Elisabetta Cerbai
- Center of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, ItalyCenter of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, ItalyCenter of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, Italy
| | - Chiara Tesi
- Center of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, ItalyCenter of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, Italy
| | - Corrado Poggesi
- Center of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, ItalyCenter of Molecular Medicine, Department of Experimental and Clinical Medicine, Division of Physiology, Department of NeuroFarBa, Division of Pharmacology, LENS, European Laboratory for Non-Linear Spectroscopy, and Department of Physics, University of Florence, 50121 Florence, Italy
| | - Henk E D J ter Keurs
- Department of Cardiac Sciences of the Libin Institute at the Faculty of Medicine, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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Abstract
Only a few neuronal populations in the central nervous system (CNS) of adult mammals show local regrowth upon dissection of their axon. In order to understand the mechanism that promotes neuronal regeneration, an in-depth analysis of the neuronal types that can remodel after injury is needed. Several studies showed that damaged climbing fibers are capable of regrowing also in adult animals. The investigation of the time-lapse dynamics of degeneration and regeneration of these axons within their complex environment can be performed by time-lapse two-photon fluorescence (TPF) imaging in vivo. This technique is here combined with laser surgery, which proved to be a highly selective tool to disrupt fluorescent structures in the intact mouse cortex. This protocol describes how to perform TPF time-lapse imaging and laser nanosurgery of single axonal branches in the cerebellum in vivo. Olivocerebellar neurons are labeled by anterograde tracing with a dextran-conjugated dye and then monitored by TPF imaging through a cranial window. The terminal portion of their axons are then dissected by irradiation with a Ti:Sapphire laser at high power. The degeneration and potential regrowth of the damaged neuron are monitored by TPF in vivo imaging during the days following the injury.
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Affiliation(s)
| | - Leonardo Sacconi
- European Laboratory for Non-Linear Spectroscopy, University of Florence; National Institute of Optics, National Research Council
| | - Francesco Saverio Pavone
- European Laboratory for Non-Linear Spectroscopy, University of Florence; National Institute of Optics, National Research Council; Department of Physics and Astronomy, University of Florence; International Center for Computational Neurophotonics (ICON Foundation)
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18
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Holtmaat A, Randall J, Cane M. Optical imaging of structural and functional synaptic plasticity in vivo. Eur J Pharmacol 2013; 719:128-136. [DOI: 10.1016/j.ejphar.2013.07.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 07/11/2013] [Indexed: 12/13/2022]
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Synaptic elimination and protection after minimal injury depend on cell type and their prelesion structural dynamics in the adult cerebral cortex. J Neurosci 2013; 33:10374-83. [PMID: 23785150 DOI: 10.1523/jneurosci.0254-13.2013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The axonal and synaptic mechanisms underlying dysfunction and repair of the injured CNS are poorly understood. Unresolved issues include to what degree, when, and how the surviving neurons degenerate and the extent of synaptic remodeling both along the severed axon and in the nearby area. One of the main reasons is the lack of tools to study the complex asynchronous and dynamic features of individual lesioned axon responses in the intact brain. To address these issues, we combined two-photon microscopy and laser microsurgery to image the real-time reorganization of cortical circuitry at synaptic resolution for periods of up to 1 year in the brain of living mice. Injured cortical axons were eliminated proximally through a two-phase retraction process, which continued for at least 3 months postlesion and was independent of the presence of scar tissue. Remarkably, axons which later attempt to regenerate in both the mature and juvenile brain retracted less, raising the possibility that targeting retraction may improve the chances of axon regrowth after axotomy. Comparing prelesion and postlesion dynamics on the same axons over several days and weeks revealed that, although synapse formation rates were unaffected, boutons on injured axons were either rapidly and persistently lost, or extremely resistant, depending on cell-type and their prelesion structural dynamics. Our data suggest a lasting deficiency in synaptic output on surviving injured cortical axons and a surprising difference in the vulnerability of synaptic boutons after axotomy, which depend on cell-type and their recent history.
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In vivo single branch axotomy induces GAP-43-dependent sprouting and synaptic remodeling in cerebellar cortex. Proc Natl Acad Sci U S A 2013; 110:10824-9. [PMID: 23754371 DOI: 10.1073/pnas.1219256110] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Plasticity in the central nervous system in response to injury is a complex process involving axonal remodeling regulated by specific molecular pathways. Here, we dissected the role of growth-associated protein 43 (GAP-43; also known as neuromodulin and B-50) in axonal structural plasticity by using, as a model, climbing fibers. Single axonal branches were dissected by laser axotomy, avoiding collateral damage to the adjacent dendrite and the formation of a persistent glial scar. Despite the very small denervated area, the injured axons consistently reshape the connectivity with surrounding neurons. At the same time, adult climbing fibers react by sprouting new branches through the intact surroundings. Newly formed branches presented varicosities, suggesting that new axons were more than just exploratory sprouts. Correlative light and electron microscopy reveals that the sprouted branch contains large numbers of vesicles, with varicosities in the close vicinity of Purkinje dendrites. By using an RNA interference approach, we found that downregulating GAP-43 causes a significant increase in the turnover of presynaptic boutons. In addition, silencing hampers the generation of reactive sprouts. Our findings show the requirement of GAP-43 in sustaining synaptic stability and promoting the initiation of axonal regrowth.
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21
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Grasselli G, Strata P. Structural plasticity of climbing fibers and the growth-associated protein GAP-43. Front Neural Circuits 2013; 7:25. [PMID: 23441024 PMCID: PMC3578352 DOI: 10.3389/fncir.2013.00025] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 02/03/2013] [Indexed: 01/12/2023] Open
Abstract
Structural plasticity occurs physiologically or after brain damage to adapt or re-establish proper synaptic connections. This capacity depends on several intrinsic and extrinsic determinants that differ between neuron types. We reviewed the significant endogenous regenerative potential of the neurons of the inferior olive (IO) in the adult rodent brain and the structural remodeling of the terminal arbor of their axons, the climbing fiber (CF), under various experimental conditions, focusing on the growth-associated protein GAP-43. CFs undergo remarkable collateral sprouting in the presence of denervated Purkinje cells (PCs) that are available for new innervation. In addition, severed olivo-cerebellar axons regenerate across the white matter through a graft of embryonic Schwann cells. In contrast, CFs undergo a regressive modification when their target is deleted. In vivo knockdown of GAP-43 in olivary neurons, leads to the atrophy of their CFs and a reduction in the ability to sprout toward surrounding denervated PCs. These findings demonstrate that GAP-43 is essential for promoting denervation-induced sprouting and maintaining normal CF architecture.
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Laperchia C, Allegra Mascaro AL, Sacconi L, Andrioli A, Mattè A, De Franceschi L, Grassi-Zucconi G, Bentivoglio M, Buffelli M, Pavone FS. Two-photon microscopy imaging of thy1GFP-M transgenic mice: a novel animal model to investigate brain dendritic cell subsets in vivo. PLoS One 2013; 8:e56144. [PMID: 23409142 PMCID: PMC3567047 DOI: 10.1371/journal.pone.0056144] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 01/07/2013] [Indexed: 12/23/2022] Open
Abstract
Transgenic mice expressing fluorescent proteins in specific cell populations are widely used for in vivo brain studies with two-photon fluorescence (TPF) microscopy. Mice of the thy1GFP-M line have been engineered for selective expression of green fluorescent protein (GFP) in neuronal populations. Here, we report that TPF microscopy reveals, at the brain surface of these mice, also motile non-neuronal GFP+ cells. We have analyzed the behavior of these cells in vivo and characterized in brain sections their immunophenotype. With TPF imaging, motile GFP+ cells were found in the meninges, subarachnoid space and upper cortical layers. The striking feature of these cells was their ability to move across the brain parenchyma, exhibiting evident shape changes during their scanning-like motion. In brain sections, GFP+ cells were immunonegative to antigens recognizing motile cells such as migratory neuroblasts, neuronal and glial precursors, mast cells, and fibroblasts. GFP+ non-neuronal cells exhibited instead the characteristic features and immunophenotype (CD11c and major histocompatibility complex molecule class II immunopositivity) of dendritic cells (DCs), and were immunonegative to the microglial marker Iba-1. GFP+ cells were also identified in lymph nodes and blood of thy1GFP-M mice, supporting their identity as DCs. Thus, TPF microscopy has here allowed the visualization for the first time of the motile behavior of brain DCs in situ. The results indicate that the thy1GFP-M mouse line provides a novel animal model for the study of subsets of these professional antigen-presenting cells in the brain. Information on brain DCs is still very limited and imaging in thy1GFP-M mice has a great potential for analyses of DC-neuron interaction in normal and pathological conditions.
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Affiliation(s)
- Claudia Laperchia
- Department of Neurological Sciences, University of Verona, Verona, Italy
- National Institute of Neuroscience, Verona, Italy
| | - Anna L. Allegra Mascaro
- European Laboratory of Non-Linear Spectroscopy, University of Florence, Sesto Fiorentino, Italy
| | - Leonardo Sacconi
- European Laboratory of Non-Linear Spectroscopy, University of Florence, Sesto Fiorentino, Italy
- National Institute of Optics, National Research Council, Florence, Italy
| | - Anna Andrioli
- Department of Neurological Sciences, University of Verona, Verona, Italy
- National Institute of Neuroscience, Verona, Italy
| | | | | | - Gigliola Grassi-Zucconi
- Department of Neurological Sciences, University of Verona, Verona, Italy
- National Institute of Neuroscience, Verona, Italy
| | - Marina Bentivoglio
- Department of Neurological Sciences, University of Verona, Verona, Italy
- National Institute of Neuroscience, Verona, Italy
| | - Mario Buffelli
- Department of Neurological Sciences, University of Verona, Verona, Italy
- National Institute of Neuroscience, Verona, Italy
- Center for Biomedical Computing, University of Verona, Verona, Italy
- * E-mail:
| | - Francesco S. Pavone
- European Laboratory of Non-Linear Spectroscopy, University of Florence, Sesto Fiorentino, Italy
- National Institute of Optics, National Research Council, Florence, Italy
- Department of Physics, University of Florence, Sesto Fiorentino, Italy
- International Center of Computational Neurophotonics, Sesto Fiorentino, Italy
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23
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Personalized nanomedicine advancements for stem cell tracking. Adv Drug Deliv Rev 2012; 64:1488-507. [PMID: 22820528 DOI: 10.1016/j.addr.2012.07.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 07/11/2012] [Indexed: 12/12/2022]
Abstract
Recent technological developments in biomedicine have facilitated the generation of data on the anatomical, physiological and molecular level for individual patients and thus introduces opportunity for therapy to be personalized in an unprecedented fashion. Generation of patient-specific stem cells exemplifies the efforts toward this new approach. Cell-based therapy is a highly promising treatment paradigm; however, due to the lack of consistent and unbiased data about the fate of stem cells in vivo, interpretation of therapeutic effects remains challenging hampering the progress in this field. The advent of nanotechnology with a wide palette of inorganic and organic nanostructures has expanded the arsenal of methods for tracking transplanted stem cells. The diversity of nanomaterials has revolutionized personalized nanomedicine and enables individualized tailoring of stem cell labeling materials for the specific needs of each patient. The successful implementation of stem cell tracking will likely be a significant driving force that will contribute to the further development of nanotheranostics. The purpose of this review is to emphasize the role of cell tracking using currently available nanoparticles.
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Yavaş S, Erdogan M, Gürel K, Ilday FÖ, Eldeniz YB, Tazebay UH. Fiber laser-microscope system for femtosecond photodisruption of biological samples. BIOMEDICAL OPTICS EXPRESS 2012; 3:605-11. [PMID: 22435105 PMCID: PMC3296545 DOI: 10.1364/boe.3.000605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 02/14/2012] [Accepted: 02/14/2012] [Indexed: 05/17/2023]
Abstract
We report on the development of a ultrafast fiber laser-microscope system for femtosecond photodisruption of biological targets. A mode-locked Yb-fiber laser oscillator generates few-nJ pulses at 32.7 MHz repetition rate, amplified up to ∼125 nJ at 1030 nm. Following dechirping in a grating compressor, ∼240 fs-long pulses are delivered to the sample through a diffraction-limited microscope, which allows real-time imaging and control. The laser can generate arbitrary pulse patterns, formed by two acousto-optic modulators (AOM) controlled by a custom-developed field-programmable gate array (FPGA) controller. This capability opens the route to fine optimization of the ablation processes and management of thermal effects. Sample position, exposure time and imaging are all computerized. The capability of the system to perform femtosecond photodisruption is demonstrated through experiments on tissue and individual cells.
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Affiliation(s)
- Seydi Yavaş
- Institute of Materials Science and Nanotechnology, Bilkent University, Ankara,
Turkey 06800
| | - Mutlu Erdogan
- Institute of Materials Science and Nanotechnology, Bilkent University, Ankara,
Turkey 06800
| | - Kutan Gürel
- Department of Physics, Bilkent University, Ankara,
Turkey 06800
| | - F. Ömer Ilday
- Department of Physics, Bilkent University, Ankara,
Turkey 06800
| | - Y. Burak Eldeniz
- Electronics Engineering Department, Ankara University, Ankara,
Turkey 06100
| | - Uygar H. Tazebay
- Department of Molecular Biology and Genetics, Bilkent University, Ankara,
Turkey 06800
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25
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Devor A, Boas D. Neurovascular imaging. FRONTIERS IN NEUROENERGETICS 2012; 4:1. [PMID: 22279435 PMCID: PMC3260454 DOI: 10.3389/fnene.2012.00001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 01/03/2011] [Indexed: 12/21/2022]
Affiliation(s)
- Anna Devor
- Neurovascular Imaging Laboratory, University of California San Diego San Diego, CA, USA
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Eiraku M, Adachi T, Sasai Y. Relaxation-expansion model for self-driven retinal morphogenesis: a hypothesis from the perspective of biosystems dynamics at the multi-cellular level. Bioessays 2012; 34:17-25. [PMID: 22052700 PMCID: PMC3266490 DOI: 10.1002/bies.201100070] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The generation of complex organ structures such as the eye requires the intricate orchestration of multiple cellular interactions. In this paper, early retinal development is discussed with respect to the structure formation of the optic cup. Although recent studies have elucidated molecular mechanisms of retinal differentiation, little is known about how the unique shape of the optic cup is determined. A recent report has demonstrated that optic-cup morphogenesis spontaneously occurs in three-dimensional stem-cell culture without external forces, indicating a latent intrinsic order to generate the structure. Based on this self-organizing phenomenon, we introduce the "relaxation-expansion" model to mechanically interpret the tissue dynamics that enable the spontaneous invagination of the neural retina. This model involves three consecutive local rules (relaxation, apical constriction, and expansion), and its computer simulation recapitulates the optic-cup morphogenesis in silico.
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Affiliation(s)
- Mototsugu Eiraku
- Organogenesis and Neurogenesis Group, RIKEN Center for Developmental BiologyKobe, Japan
- Unit for Four-Dimensional Tissue Analysis, RIKEN Center for Developmental BiologyKobe, Japan
| | - Taiji Adachi
- Department of Biomechanics, Institute for Frontier Medical Sciences, Kyoto UniversityKyoto, Japan
- Computational Cell Biomechanics Team, VCAD System Research ProgramRIKEN, Wako, Japan
| | - Yoshiki Sasai
- Organogenesis and Neurogenesis Group, RIKEN Center for Developmental BiologyKobe, Japan
- Unit for Four-Dimensional Tissue Analysis, RIKEN Center for Developmental BiologyKobe, Japan
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Characterization and adaptive optical correction of aberrations during in vivo imaging in the mouse cortex. Proc Natl Acad Sci U S A 2011; 109:22-7. [PMID: 22190489 DOI: 10.1073/pnas.1109202108] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The signal and resolution during in vivo imaging of the mouse brain is limited by sample-induced optical aberrations. We find that, although the optical aberrations can vary across the sample and increase in magnitude with depth, they remain stable for hours. As a result, two-photon adaptive optics can recover diffraction-limited performance to depths of 450 μm and improve imaging quality over fields of view of hundreds of microns. Adaptive optical correction yielded fivefold signal enhancement for small neuronal structures and a threefold increase in axial resolution. The corrections allowed us to detect smaller neuronal structures at greater contrast and also improve the signal-to-noise ratio during functional Ca(2+) imaging in single neurons.
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Kunik D, Dion C, Ozaki T, Levin LA, Costantino S. Laser-based single-axon transection for high-content axon injury and regeneration studies. PLoS One 2011; 6:e26832. [PMID: 22073205 PMCID: PMC3206876 DOI: 10.1371/journal.pone.0026832] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 10/05/2011] [Indexed: 01/15/2023] Open
Abstract
The investigation of the regenerative response of the neurons to axonal injury is essential to the development of new axoprotective therapies. Here we study the retinal neuronal RGC-5 cell line after laser transection, demonstrating that the ability of these cells to initiate a regenerative response correlates with axon length and cell motility after injury. We show that low energy picosecond laser pulses can achieve transection of unlabeled single axons in vitro and precisely induce damage with micron precision. We established the conditions to achieve axon transection, and characterized RGC-5 axon regeneration and cell body response using time-lapse microscopy. We developed an algorithm to analyze cell trajectories and established correlations between cell motility after injury, axon length, and the initiation of the regeneration response. The characterization of the motile response of axotomized RGC-5 cells showed that cells that were capable of repair or regrowth of damaged axons migrated more slowly than cells that could not. Moreover, we established that RGC-5 cells with long axons could not recover their injured axons, and such cells were much more motile. The platform we describe allows highly controlled axonal damage with subcellular resolution and the performance of high-content screening in cell cultures.
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Affiliation(s)
- Darío Kunik
- Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Quebec, Canada
- Institut de Génie Biomédical, Université de Montréal, Montréal, Quebec, Canada
| | - Carolyne Dion
- Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Quebec, Canada
- Energie Materiaux et Communications, Institut National de la Recherche Scientifique, Quebec City, Quebec, Canada
| | - Tsuneyuki Ozaki
- Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Quebec, Canada
- Energie Materiaux et Communications, Institut National de la Recherche Scientifique, Quebec City, Quebec, Canada
| | - Leonard A. Levin
- Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Quebec, Canada
- Département d'Ophtalmologie Université de Montréal, Montréal, Quebec, Canada
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Santiago Costantino
- Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Montréal, Quebec, Canada
- Institut de Génie Biomédical, Université de Montréal, Montréal, Quebec, Canada
- Département d'Ophtalmologie Université de Montréal, Montréal, Quebec, Canada
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Self-organizing optic-cup morphogenesis in three-dimensional culture. Nature 2011; 472:51-6. [PMID: 21475194 DOI: 10.1038/nature09941] [Citation(s) in RCA: 1349] [Impact Index Per Article: 103.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 02/17/2011] [Indexed: 12/20/2022]
Abstract
Balanced organogenesis requires the orchestration of multiple cellular interactions to create the collective cell behaviours that progressively shape developing tissues. It is currently unclear how individual, localized parts are able to coordinate with each other to develop a whole organ shape. Here we report the dynamic, autonomous formation of the optic cup (retinal primordium) structure from a three-dimensional culture of mouse embryonic stem cell aggregates. Embryonic-stem-cell-derived retinal epithelium spontaneously formed hemispherical epithelial vesicles that became patterned along their proximal-distal axis. Whereas the proximal portion differentiated into mechanically rigid pigment epithelium, the flexible distal portion progressively folded inward to form a shape reminiscent of the embryonic optic cup, exhibited interkinetic nuclear migration and generated stratified neural retinal tissue, as seen in vivo. We demonstrate that optic-cup morphogenesis in this simple cell culture depends on an intrinsic self-organizing program involving stepwise and domain-specific regulation of local epithelial properties.
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30
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Antony PMA, Diederich NJ, Balling R. Parkinson's disease mouse models in translational research. Mamm Genome 2011; 22:401-19. [PMID: 21559878 PMCID: PMC3151483 DOI: 10.1007/s00335-011-9330-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 04/14/2011] [Indexed: 12/21/2022]
Abstract
Animal models with high predictive power are a prerequisite for translational research. The closer the similarity of a model to Parkinson’s disease (PD), the higher is the predictive value for clinical trials. An ideal PD model should present behavioral signs and pathology that resemble the human disease. The increasing understanding of PD stratification and etiology, however, complicates the choice of adequate animal models for preclinical studies. An ultimate mouse model, relevant to address all PD-related questions, is yet to be developed. However, many of the existing models are useful in answering specific questions. An appropriate model should be chosen after considering both the context of the research and the model properties. This review addresses the validity, strengths, and limitations of current PD mouse models for translational research.
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Affiliation(s)
- Paul M A Antony
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Luxembourg.
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Kuetemeyer K, Rezgui R, Lubatschowski H, Heisterkamp A. Influence of laser parameters and staining on femtosecond laser-based intracellular nanosurgery. BIOMEDICAL OPTICS EXPRESS 2010; 1:587-597. [PMID: 21258492 PMCID: PMC3017989 DOI: 10.1364/boe.1.000587] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 08/05/2010] [Accepted: 08/05/2010] [Indexed: 05/19/2023]
Abstract
Femtosecond (fs) laser-based intracellular nanosurgery has become an important tool in cell biology, albeit the mechanisms in the so-called low-density plasma regime are largely unknown. Previous calculations of free-electron densities for intracellular surgery used water as a model substance for biological media and neglected the presence of dye and biomolecules. In addition, it is still unclear on which time scales free-electron and free-radical induced chemical effects take place in a cellular environment. Here, we present our experimental study on the influence of laser parameters and staining on the intracellular ablation threshold in the low-density plasma regime. We found that the ablation effect of fs laser pulse trains resulted from the accumulation of single-shot multiphoton-induced photochemical effects finished within a few nanoseconds. At the threshold, the number of applied pulses was inversely proportional to a higher order of the irradiance, depending on the laser repetition rate and wavelength. Furthermore, fluorescence staining of subcellular structures before surgery significantly decreased the ablation threshold. Based on our findings, we propose that dye molecules are the major source for providing seed electrons for the ionization cascade. Consequently, future calculations of free-electron densities for intracellular nanosurgery have to take them into account, especially in the calculations of multiphoton ionization rates.
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Affiliation(s)
| | - R. Rezgui
- Laser Zentrum Hannover e.V., Hollerithallee 8, 30419
Hannover, Germany
| | - H. Lubatschowski
- Laser Zentrum Hannover e.V., Hollerithallee 8, 30419
Hannover, Germany
| | - A. Heisterkamp
- Laser Zentrum Hannover e.V., Hollerithallee 8, 30419
Hannover, Germany
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