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von Streitberg A, Jäkel S, Eugenin von Bernhardi J, Straube C, Buggenthin F, Marr C, Dimou L. NG2-Glia Transiently Overcome Their Homeostatic Network and Contribute to Wound Closure After Brain Injury. Front Cell Dev Biol 2021; 9:662056. [PMID: 34012966 PMCID: PMC8128074 DOI: 10.3389/fcell.2021.662056] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 03/12/2021] [Indexed: 12/27/2022] Open
Abstract
In the adult brain, NG2-glia represent a cell population that responds to injury. To further investigate if, how and why NG2-glia are recruited to the injury site, we analyzed in detail the long-term reaction of NG2-glia after a lesion by time-lapse two-photon in vivo microscopy. Live imaging over several weeks of GFP-labeled NG2-glia in the stab wounded cerebral cortex revealed their fast and heterogeneous reaction, including proliferation, migration, polarization, hypertrophy, or a mixed response, while a small subset of cells remained unresponsive. At the peak of the reaction, 2-4 days after the injury, NG2-glia accumulated around and within the lesion core, overcoming the homeostatic control of their density, which normalized back to physiological conditions only 4 weeks after the insult. Genetic ablation of proliferating NG2-glia demonstrated that this accumulation contributed beneficially to wound closure. Thus, NG2-glia show a fast response to traumatic brain injury (TBI) and participate in tissue repair.
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Affiliation(s)
- Axel von Streitberg
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Sarah Jäkel
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Jaime Eugenin von Bernhardi
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians-University Munich, Munich, Germany.,Molecular and Translational Neuroscience, Department of Neurology, Ulm University, Ulm, Germany
| | - Christoph Straube
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Felix Buggenthin
- Institute of Computational Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Carsten Marr
- Institute of Computational Biology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Leda Dimou
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians-University Munich, Munich, Germany.,Molecular and Translational Neuroscience, Department of Neurology, Ulm University, Ulm, Germany
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Dipold J, Vivas MG, Koeckelberghs G, Siqueira JP, De Boni L, Mendonca CR. Probing the Strong Near-IR Two-Photon Transition in Supramolecular Triphenylamine-based Polymers by Nonlinear Absorption Spectroscopy. J Phys Chem B 2020; 124:6147-6153. [PMID: 32539394 DOI: 10.1021/acs.jpcb.0c04127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Due to their capability of film formation and remarkable optical features, semiconductor polymers with high two-photon absorption (2PA) have been studied as potential candidates for the development of organic photonic platforms. Furthermore, there is a high demand for photonic devices operating in the near-infrared (IR) region. However, the magnitude of the nonlinear optical response of random coil polymers in the IR region is weak due to the loss of molecular structure caused by increasing the π-conjugated backbone. Thus, herein we aim to investigate the molecular structure and 2PA features relationship for four polymers with supramolecular (helical) rodlike structure. Such polymers have a rigid core based on triphenylamine groups connected to the chiral binaphthalene units and a strong electron-withdrawing group (EWG). This kind of structure allows a very high chromophore density, which was responsible for generating 2PA cross-section between 305 GM and 565 GM in the near-IR (900-1300 nm), depending on the EWG strength. in light of the two-level model within the sum-overstates approach, we estimated the degree of intramolecular charge transfer induced by 2PA in the IR region, and values as high as 50-70% were found. Such a critical outcome allows the 2PA cross-section in the IR region to remain high even though the ratio between the visible/IR-band 2PA cross-section increases as a function of EWG strength.
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Affiliation(s)
- Jessica Dipold
- Instituto de Fı́sica de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, São Paulo, Brazil
| | - Marcelo G Vivas
- Laboratório de Espectroscopia Óptica e Fotônica, Universidade Federal de Alfenas, Poços de Caldas, Minas Gerais 37715-400, Brazil
| | - Guy Koeckelberghs
- Laboratory for Polymer Synthesis, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, B-3001 Leuven, Belgium
| | - Jonathas P Siqueira
- Instituto de Fı́sica de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, São Paulo, Brazil.,Instituto de Fı́sica "Gleb Wataghin", Universidade Estadual de Campinas, Campinas, São Paulo 13083-859, Brazil
| | - Leonardo De Boni
- Instituto de Fı́sica de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, São Paulo, Brazil
| | - Cleber R Mendonca
- Instituto de Fı́sica de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, São Paulo, Brazil
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Jia X, Zhou W, Huang F, Guo H, Hu J. Monitoring algorithm of tilt angle based on sub-block plane fitting for high-resolution imaging. APPLIED OPTICS 2019; 58:5873-5882. [PMID: 31503894 DOI: 10.1364/ao.58.005873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 06/26/2019] [Indexed: 06/10/2023]
Abstract
The limitation of mechanical structure and misoperations can result in a small tilt angle formed by the sample and the focal plane, which will decrease the resolution of the imaging system. Moreover, the small tilt angle is difficult to be observed. In order to solve this problem, a monitoring algorithm of tilt angle based on sub-block plane fitting for high-resolution imaging systems has been proposed, which is used to measure the initial angle of most 2D samples before imaging and assist users to determine the tilt degree of the sample. Experiments demonstrate that the proposed method can measure the tilt angle with a high measurement precision of 0.007° and a low residual tilt angle of 0.004°, indicating that the algorithm has high measurement precision and stability. Further results show that the quality of the image will be improved by 20%-27% when the tilt angle is 0.3056°, which means that the small degree of tilt of the sample can seriously damage the image quality. Therefore, the study of tilt angle measurement has great significance for high-resolution imaging systems.
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Tang W, Fan W, Lau J, Deng L, Shen Z, Chen X. Emerging blood–brain-barrier-crossing nanotechnology for brain cancer theranostics. Chem Soc Rev 2019; 48:2967-3014. [DOI: 10.1039/c8cs00805a] [Citation(s) in RCA: 242] [Impact Index Per Article: 48.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The advancements, perspectives, and challenges in blood–brain-barrier (BBB)-crossing nanotechnology for effective brain tumor delivery and highly efficient brain cancer theranostics.
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Affiliation(s)
- Wei Tang
- Laboratory of Molecular Imaging and Nanomedicine (LOMIN)
- National Institute of Biomedical Imaging and Bioengineering (NIBIB)
- National Institutes of Health (NIH)
- Bethesda
- USA
| | - Wenpei Fan
- Laboratory of Molecular Imaging and Nanomedicine (LOMIN)
- National Institute of Biomedical Imaging and Bioengineering (NIBIB)
- National Institutes of Health (NIH)
- Bethesda
- USA
| | - Joseph Lau
- Laboratory of Molecular Imaging and Nanomedicine (LOMIN)
- National Institute of Biomedical Imaging and Bioengineering (NIBIB)
- National Institutes of Health (NIH)
- Bethesda
- USA
| | - Liming Deng
- Laboratory of Molecular Imaging and Nanomedicine (LOMIN)
- National Institute of Biomedical Imaging and Bioengineering (NIBIB)
- National Institutes of Health (NIH)
- Bethesda
- USA
| | - Zheyu Shen
- Laboratory of Molecular Imaging and Nanomedicine (LOMIN)
- National Institute of Biomedical Imaging and Bioengineering (NIBIB)
- National Institutes of Health (NIH)
- Bethesda
- USA
| | - Xiaoyuan Chen
- Laboratory of Molecular Imaging and Nanomedicine (LOMIN)
- National Institute of Biomedical Imaging and Bioengineering (NIBIB)
- National Institutes of Health (NIH)
- Bethesda
- USA
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Tran CHT, Gordon GR. Acute two-photon imaging of the neurovascular unit in the cortex of active mice. Front Cell Neurosci 2015; 9:11. [PMID: 25698926 PMCID: PMC4318346 DOI: 10.3389/fncel.2015.00011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 01/09/2015] [Indexed: 12/31/2022] Open
Abstract
In vivo two-photon scanning fluorescence imaging is a powerful technique to observe physiological processes from the millimeter to the micron scale in the intact animal. In neuroscience research, a common approach is to install an acute cranial window and head bar to explore neocortical function under anesthesia before inflammation peaks from the surgery. However, there are few detailed acute protocols for head-restrained and fully awake animal imaging of the neurovascular unit during activity. This is because acutely performed awake experiments are typically untenable when the animal is naïve to the imaging apparatus. Here we detail a method that achieves acute, deep-tissue two-photon imaging of neocortical astrocytes and microvasculature in behaving mice. A week prior to experimentation, implantation of the head bar alone allows mice to train for head-immobilization on an easy-to-learn air-supported ball treadmill. Following just two brief familiarization sessions to the treadmill on separate days, an acute cranial window can subsequently be installed for immediate imaging. We demonstrate how running and whisking data can be captured simultaneously with two-photon fluorescence signals with acceptable movement artifacts during active motion. We also show possible applications of this technique by (1) monitoring dynamic changes to microvascular diameter and red blood cells in response to vibrissa sensory stimulation, (2) examining responses of the cerebral microcirculation to the systemic delivery of pharmacological agents using a tail artery cannula during awake imaging, and (3) measuring Ca(2+) signals from synthetic and genetically encoded Ca(2+) indicators in astrocytes. This method will facilitate acute two-photon fluorescence imaging in awake, active mice and help link cellular events within the neurovascular unit to behavior.
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Affiliation(s)
- Cam Ha T Tran
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary Calgary, AB, Canada
| | - Grant R Gordon
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary Calgary, AB, Canada
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Iwabuchi S, Koh JY, Wardenburg M, Johnson JD, Harata NC. Light-microscope specimen holder with 3-axis rotation and small-angle control. J Neurosci Methods 2014; 221:15-21. [PMID: 24025262 DOI: 10.1016/j.jneumeth.2013.08.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 08/28/2013] [Accepted: 08/29/2013] [Indexed: 11/17/2022]
Abstract
BACKGROUND Although recent developments in methodologies for light microscopy have enabled imaging of fine biological structures, such imaging is often accompanied by two types of problems. One is a tilting of the specimen with respect to the x-y plane (i.e. rotation around the x- or y-axis) such that the sample is not perpendicular to the optical z-axis, and the other is rotation around the z-axis that precludes optimal orientations for imaging and experimentation. These rotation problems can cause optical aberrations and hamper imaging experiments, even when the angular difference from the ideal position is small. NEW METHOD In order to correct for these practical issues, we have developed a specimen holder with 3-axis (x-y-z) rotation for an inverted light microscope. This allows for full-range rotations of 2-4° for x-, y-axes, ~24° for z-axis, and a small-angle control of <0.1° for either axis. RESULTS Using this device, we observed the cultured hippocampal neurons stained by immunofluorescence for a dendritic marker, or the sub-resolution fluorescent beads plated on a glass coverslip. The rotations and associated problems could be manipulated, while viewing the specimens by laser-scanning confocal microscopy. COMPARISON WITH EXISTING METHODS This tilting/rotation device is easily manufactured and installed on a conventional microscope stage without requiring changes to the existing optical components. Similar devices with full capability have not been available. CONCLUSIONS It will be useful for imaging experiments with biomedical applications.
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Affiliation(s)
- Sadahiro Iwabuchi
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, IA, USA
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Stetter C, Hirschberg M, Nieswandt B, Ernestus RI, Heckmann M, Sirén AL. An experimental protocol for in vivo imaging of neuronal structural plasticity with 2-photon microscopy in mice. EXPERIMENTAL & TRANSLATIONAL STROKE MEDICINE 2013; 5:9. [PMID: 23842538 PMCID: PMC3716956 DOI: 10.1186/2040-7378-5-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 07/09/2013] [Indexed: 06/02/2023]
Abstract
INTRODUCTION Structural plasticity with synapse formation and elimination is a key component of memory capacity and may be critical for functional recovery after brain injury. Here we describe in detail two surgical techniques to create a cranial window in mice and show crucial points in the procedure for long-term repeated in vivo imaging of synaptic structural plasticity in the mouse neocortex. METHODS Transgenic Thy1-YFP(H) mice expressing yellow-fluorescent protein (YFP) in layer-5 pyramidal neurons were prepared under anesthesia for in vivo imaging of dendritic spines in the parietal cortex either with an open-skull glass or thinned skull window. After a recovery period of 14 days, imaging sessions of 45-60 min in duration were started under fluothane anesthesia. To reduce respiration-induced movement artifacts, the skull was glued to a stainless steel plate fixed to metal base. The animals were set under a two-photon microscope with multifocal scanhead splitter (TriMScope, LaVision BioTec) and the Ti-sapphire laser was tuned to the optimal excitation wavelength for YFP (890 nm). Images were acquired by using a 20×, 0.95 NA, water-immersion objective (Olympus) in imaging depth of 100-200 μm from the pial surface. Two-dimensional projections of three-dimensional image stacks containing dendritic segments of interest were saved for further analysis. At the end of the last imaging session, the mice were decapitated and the brains removed for histological analysis. RESULTS Repeated in vivo imaging of dendritic spines of the layer-5 pyramidal neurons was successful using both open-skull glass and thinned skull windows. Both window techniques were associated with low phototoxicity after repeated sessions of imaging. CONCLUSIONS Repeated imaging of dendritic spines in vivo allows monitoring of long-term structural dynamics of synapses. When carefully controlled for influence of repeated anesthesia and phototoxicity, the method will be suitable to study changes in synaptic structural plasticity after brain injury.
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Affiliation(s)
- Christian Stetter
- Department of Neurosurgery, University of Würzburg, Josef-Schneider-Str. 11, 97080 Würzburg, Germany
| | | | | | - Ralf-Ingo Ernestus
- Department of Neurosurgery, University of Würzburg, Josef-Schneider-Str. 11, 97080 Würzburg, Germany
| | - Manfred Heckmann
- Institute for Neurophysiology, University of Würzburg, Würzburg, Germany
| | - Anna-Leena Sirén
- Department of Neurosurgery, University of Würzburg, Josef-Schneider-Str. 11, 97080 Würzburg, Germany
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