1
|
Hawker B, Dhakal M, Connor B, McCaughey-Chapman A. Modeling demyelination and endogenous remyelination in spinal cord ex vivo rat organotypic slice cultures. Front Cell Neurosci 2024; 18:1345042. [PMID: 38988661 PMCID: PMC11233765 DOI: 10.3389/fncel.2024.1345042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 06/17/2024] [Indexed: 07/12/2024] Open
Abstract
Introduction Demyelination of the spinal cord is a prominent feature of multiple sclerosis (MS) and spinal cord injuries (SCI), where impaired neuronal communication between the brain and periphery has devastating consequences on neurological function. Demyelination precedes remyelination, an endogenous process in which oligodendrocyte precursor cells (OPCs) differentiate into mature, myelinating oligodendrocytes with the ability to restore the myelin sheath and reinstate functional nerve signaling. However, in MS or SCI, demyelination is more severe, persistent, and inhibitory to OPC-mediated remyelination, leading to a permanent loss of neuronal function. Currently, there are no effective treatments for demyelination, and existing pre-clinical models typically focus on brain tissue with little characterization of demyelination within the spinal cord. Organotypic slice cultures are a useful tool to study neurological disease, providing a more complex 3-dimensional system than standard 2-dimensional in vitro cell cultures. Methods Building on our previously developed rat brain slice culture protocol, we have extended our findings to develop a rat longitudinal spinal cord ex vivo model of demyelination. Results We generated rat longitudinal spinal cord slice cultures that remain viable for up to 6 weeks in culture and retain key anatomical features of the spinal cord's cytoarchitecture. We show that treating longitudinal spinal cord slices with lysolecithin (LPC) induced robust demyelination with some endogenous remyelination, which was not seen following exposure to lipopolysaccharide (LPS). Discussion Our ex vivo organotypic spinal cord slice culture system provides a platform to model demyelination and endogenous remyelination long-term, mimicking that observed in LPC-induced rodent models of demyelination. This platform is suitable for the development and testing of novel therapeutic strategies with ease of manipulation prior to in vivo experimentation.
Collapse
Affiliation(s)
| | | | | | - Amy McCaughey-Chapman
- Department of Pharmacology and Clinical Pharmacology, Centre for Brain Research, School of Medical Science, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| |
Collapse
|
2
|
Amato CM, Yao HHC. New uses for an old technique: live imaging on the slice organ culture to study reproductive processes†. Biol Reprod 2024; 110:1055-1064. [PMID: 38315794 PMCID: PMC11180704 DOI: 10.1093/biolre/ioae023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/24/2024] [Accepted: 01/26/2024] [Indexed: 02/07/2024] Open
Abstract
Reproductive processes are dynamic and involve extensive morphological remodeling and cell-cell interactions. Live imaging of organs enhances our understanding of how biological processes occur in real time. Slice culture is a type of organ culture where thick slices are collected from an organ and cultured for several days. Slice culture is a useful and easy-to-implement technique for live imaging of reproductive events at cellular resolution. Here we describe a pipeline of live imaging on slice culture to visualize the process of urethra closure in mouse embryonic penis as a proof of principle. In combination with genetic reporter mice, nuclear stains, and exposure experiments, we demonstrate the feasibility of slice culture on a reproductive organ. We also provide a step-by-step protocol and troubleshooting guide to facilitate the adoption of slice culture with live imaging in other reproductive organs. Lastly, we discuss potential utilities and experiments that could be implemented with slice culture in reproductive sciences.
Collapse
Affiliation(s)
- Ciro Maurizio Amato
- Reproductive Developmental Biology Group, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Humphrey Hung-Chang Yao
- Reproductive Developmental Biology Group, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| |
Collapse
|
3
|
Bak A, Koch H, van Loo KMJ, Schmied K, Gittel B, Weber Y, Ort J, Schwarz N, Tauber SC, Wuttke TV, Delev D. Human organotypic brain slice cultures: a detailed and improved protocol for preparation and long-term maintenance. J Neurosci Methods 2024; 404:110055. [PMID: 38184112 DOI: 10.1016/j.jneumeth.2023.110055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 12/11/2023] [Accepted: 12/31/2023] [Indexed: 01/08/2024]
Abstract
The investigation of the human brain at cellular and microcircuit level remains challenging due to the fragile viability of neuronal tissue, inter- and intra-variability of the samples and limited availability of human brain material. Especially brain slices have proven to be an excellent source to investigate brain physiology and disease at cellular and small network level, overcoming the temporal limits of acute slices. Here we provide a revised, detailed protocol of the production and in-depth knowledge on long-term culturing of such human organotypic brain slice cultures for research purposes. We highlight the critical pitfalls of the culturing process of the human brain tissue and present exemplary results on viral expression, single-cell Patch-Clamp recordings, as well as multi-electrode array recordings as readouts for culture viability, enabling the use of organotypic brain slice cultures of these valuable tissue samples for basic neuroscience and disease modeling (Fig. 1).
Collapse
Affiliation(s)
- Aniella Bak
- Department of Epileptology, Neurology, RWTH Aachen University Hospital, Aachen, Germany.
| | - Henner Koch
- Department of Epileptology, Neurology, RWTH Aachen University Hospital, Aachen, Germany
| | - Karen M J van Loo
- Department of Epileptology, Neurology, RWTH Aachen University Hospital, Aachen, Germany; Department of Neurosurgery, RWTH Aachen University, Aachen, Germany
| | - Katharina Schmied
- Department of Epileptology, Neurology, RWTH Aachen University Hospital, Aachen, Germany
| | - Birgit Gittel
- Department of Epileptology, Neurology, RWTH Aachen University Hospital, Aachen, Germany
| | - Yvonne Weber
- Department of Epileptology, Neurology, RWTH Aachen University Hospital, Aachen, Germany
| | - Jonas Ort
- Department of Neurosurgery, RWTH Aachen University, Aachen, Germany
| | - Niklas Schwarz
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Simone C Tauber
- Department of Neurology, RWTH Aachen University Hospital, Aachen, Germany
| | - Thomas V Wuttke
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; Department of Neurosurgery, University of Tübingen, Tübingen, Germany
| | - Daniel Delev
- Department of Neurosurgery, RWTH Aachen University, Aachen, Germany; Neurosurgical Artificial Intelligence Laboratory Aachen (NAILA), RWTH Aachen University Hospital, Aachen, Germany; Department of Neurosurgery, University of Erlangen, Erlangen, Germany
| |
Collapse
|
4
|
Taylor LW, Simzer EM, Pimblett C, Lacey-Solymar OTT, McGeachan RI, Meftah S, Rose JL, Spires-Jones MP, Holt K, Catterson JH, Koch H, Liaquat I, Clarke JH, Skidmore J, Smith C, Booker SA, Brennan PM, Spires-Jones TL, Durrant CS. p-tau Ser356 is associated with Alzheimer's disease pathology and is lowered in brain slice cultures using the NUAK inhibitor WZ4003. Acta Neuropathol 2024; 147:7. [PMID: 38175261 PMCID: PMC10766794 DOI: 10.1007/s00401-023-02667-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 11/14/2023] [Accepted: 12/07/2023] [Indexed: 01/05/2024]
Abstract
Tau hyperphosphorylation and aggregation is a common feature of many dementia-causing neurodegenerative diseases. Tau can be phosphorylated at up to 85 different sites, and there is increasing interest in whether tau phosphorylation at specific epitopes, by specific kinases, plays an important role in disease progression. The AMP-activated protein kinase (AMPK)-related enzyme NUAK1 has been identified as a potential mediator of tau pathology, whereby NUAK1-mediated phosphorylation of tau at Ser356 prevents the degradation of tau by the proteasome, further exacerbating tau hyperphosphorylation and accumulation. This study provides a detailed characterisation of the association of p-tau Ser356 with progression of Alzheimer's disease pathology, identifying a Braak stage-dependent increase in p-tau Ser356 protein levels and an almost ubiquitous presence in neurofibrillary tangles. We also demonstrate, using sub-diffraction-limit resolution array tomography imaging, that p-tau Ser356 co-localises with synapses in AD postmortem brain tissue, increasing evidence that this form of tau may play important roles in AD progression. To assess the potential impacts of pharmacological NUAK inhibition in an ex vivo system that retains multiple cell types and brain-relevant neuronal architecture, we treated postnatal mouse organotypic brain slice cultures from wildtype or APP/PS1 littermates with the commercially available NUAK1/2 inhibitor WZ4003. Whilst there were no genotype-specific effects, we found that WZ4003 results in a culture-phase-dependent loss of total tau and p-tau Ser356, which corresponds with a reduction in neuronal and synaptic proteins. By contrast, application of WZ4003 to live human brain slice cultures results in a specific lowering of p-tau Ser356, alongside increased neuronal tubulin protein. This work identifies differential responses of postnatal mouse organotypic brain slice cultures and adult human brain slice cultures to NUAK1 inhibition that will be important to consider in future work developing tau-targeting therapeutics for human disease.
Collapse
Affiliation(s)
- Lewis W Taylor
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, UK
| | - Elizabeth M Simzer
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, UK
| | - Claire Pimblett
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | | | - Robert I McGeachan
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, UK
- The Hospital for Small Animals, Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Edinburgh, UK
| | - Soraya Meftah
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, UK
| | - Jamie L Rose
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, UK
| | | | - Kristján Holt
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, UK
| | - James H Catterson
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, UK
| | - Henner Koch
- Department of Neurology, Epileptology, RWTH Aachen University Hospital, 52074, Aachen, Germany
| | - Imran Liaquat
- Department of Clinical Neuroscience, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh, UK
| | - Jonathan H Clarke
- The ALBORADA Drug Discovery Institute, University of Cambridge, Island Research Building, Cambridge Biomedical Campus, Hills Road, Cambridge, UK
| | - John Skidmore
- The ALBORADA Drug Discovery Institute, University of Cambridge, Island Research Building, Cambridge Biomedical Campus, Hills Road, Cambridge, UK
| | - Colin Smith
- The Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Sam A Booker
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain, The University of Edinburgh, Edinburgh, UK
| | - Paul M Brennan
- Department of Clinical Neuroscience, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh, UK
- The Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK
- Cancer Research UK Brain Tumour Centre of Excellence, CRUK Edinburgh Centre, The University of Edinburgh, Edinburgh, UK
| | - Tara L Spires-Jones
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, UK
| | - Claire S Durrant
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK.
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, UK.
| |
Collapse
|
5
|
Steiner K, Humpel C. Long-term organotypic brain slices cultured on collagen-based microcontact prints: A perspective for a brain-on-a-chip. J Neurosci Methods 2023; 399:109979. [PMID: 37783349 DOI: 10.1016/j.jneumeth.2023.109979] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/21/2023] [Accepted: 09/29/2023] [Indexed: 10/04/2023]
Abstract
Organotypic brain slices are three-dimensional 150 µm-thick sections of a postnatal day 10 mouse and can be cultured for several weeks in vitro. In such brain slices the complex cellular connections are preserved with a high viability. These brain slices can be connected to collagen-loaded microcontact prints to develop a simple brain-on-a-chip model. Using the microcontact printing technique, many peptides or proteins can be printed onto a semipermeable membrane and linked to brain slices. On these microcontact prints, brain-derived nerve fibers grow out, or microglia can get activated and migrate out, or also new brain vessels can be formed. Such a brain-on-a-chip model may allow to develop new drugs or a diagnostic method for neurodegenerative diseases.
Collapse
Affiliation(s)
- Katharina Steiner
- Laboratory of Psychiatry and Experimental Alzheimer's Research, Medical University of Innsbruck, Austria
| | - Christian Humpel
- Laboratory of Psychiatry and Experimental Alzheimer's Research, Medical University of Innsbruck, Austria.
| |
Collapse
|
6
|
Dembitskaya Y, Boyce AKJ, Idziak A, Pourkhalili Langeroudi A, Arizono M, Girard J, Le Bourdellès G, Ducros M, Sato-Fitoussi M, Ochoa de Amezaga A, Oizel K, Bancelin S, Mercier L, Pfeiffer T, Thompson RJ, Kim SK, Bikfalvi A, Nägerl UV. Shadow imaging for panoptical visualization of brain tissue in vivo. Nat Commun 2023; 14:6411. [PMID: 37828018 PMCID: PMC10570379 DOI: 10.1038/s41467-023-42055-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 09/25/2023] [Indexed: 10/14/2023] Open
Abstract
Progress in neuroscience research hinges on technical advances in visualizing living brain tissue with high fidelity and facility. Current neuroanatomical imaging approaches either require tissue fixation (electron microscopy), do not have cellular resolution (magnetic resonance imaging) or only give a fragmented view (fluorescence microscopy). Here, we show how regular light microscopy together with fluorescence labeling of the interstitial fluid in the extracellular space provide comprehensive optical access in real-time to the anatomical complexity and dynamics of living brain tissue at submicron scale. Using several common fluorescence microscopy modalities (confocal, light-sheet and 2-photon microscopy) in mouse organotypic and acute brain slices and the intact mouse brain in vivo, we demonstrate the value of this straightforward 'shadow imaging' approach by revealing neurons, microglia, tumor cells and blood capillaries together with their complete anatomical tissue contexts. In addition, we provide quantifications of perivascular spaces and the volume fraction of the extracellular space of brain tissue in vivo.
Collapse
Affiliation(s)
- Yulia Dembitskaya
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297 and University of Bordeaux, F-33000, Bordeaux, France
| | - Andrew K J Boyce
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297 and University of Bordeaux, F-33000, Bordeaux, France
- Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Agata Idziak
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297 and University of Bordeaux, F-33000, Bordeaux, France
| | | | - Misa Arizono
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297 and University of Bordeaux, F-33000, Bordeaux, France
- Department of Pharmacology, Kyoto University Graduate School of Medicine/The Hakubi Center for Advanced Research, Kyoto University, Kyoto, Japan
| | - Jordan Girard
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297 and University of Bordeaux, F-33000, Bordeaux, France
| | - Guillaume Le Bourdellès
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297 and University of Bordeaux, F-33000, Bordeaux, France
| | - Mathieu Ducros
- Université de Bordeaux, CNRS, INSERM, Bordeaux Imaging Center (BIC), UAR 3420, US 4, F-33000, Bordeaux, France
| | - Marie Sato-Fitoussi
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297 and University of Bordeaux, F-33000, Bordeaux, France
| | - Amaia Ochoa de Amezaga
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297 and University of Bordeaux, F-33000, Bordeaux, France
| | - Kristell Oizel
- Université de Bordeaux, INSERM, Bordeaux Institute of Oncology (BRIC), U1312, Bat B2, Allée Geoffroy St Hilaire, 33615, Pessac, France
| | - Stephane Bancelin
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297 and University of Bordeaux, F-33000, Bordeaux, France
| | - Luc Mercier
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297 and University of Bordeaux, F-33000, Bordeaux, France
| | - Thomas Pfeiffer
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297 and University of Bordeaux, F-33000, Bordeaux, France
| | - Roger J Thompson
- Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Sun Kwang Kim
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297 and University of Bordeaux, F-33000, Bordeaux, France
- Department of Physiology, College of Korean Medicine, Kyung Hee University, Seoul, 02447, Korea
| | - Andreas Bikfalvi
- Université de Bordeaux, INSERM, Bordeaux Institute of Oncology (BRIC), U1312, Bat B2, Allée Geoffroy St Hilaire, 33615, Pessac, France
| | - U Valentin Nägerl
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297 and University of Bordeaux, F-33000, Bordeaux, France.
| |
Collapse
|
7
|
Idziak A, Inavalli VVGK, Bancelin S, Arizono M, Nägerl UV. The Impact of Chemical Fixation on the Microanatomy of Mouse Organotypic Hippocampal Slices. eNeuro 2023; 10:ENEURO.0104-23.2023. [PMID: 37709524 PMCID: PMC10521345 DOI: 10.1523/eneuro.0104-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 07/26/2023] [Accepted: 07/28/2023] [Indexed: 09/16/2023] Open
Abstract
Chemical fixation using paraformaldehyde (PFA) is a standard step for preserving cells and tissues for subsequent microscopic analyses such as immunofluorescence or electron microscopy (EM). However, chemical fixation may introduce physical alterations in the spatial arrangement of cellular proteins, organelles, and membranes. With the increasing use of super-resolution microscopy to visualize cellular structures with nanometric precision, assessing potential artifacts, and knowing how to avoid them, takes on special urgency. We addressed this issue by taking advantage of live-cell super-resolution microscopy that makes it possible to directly observe the acute effects of PFA on organotypic hippocampal brain slices, allowing us to compare tissue integrity in a "before-and-after" experiment. We applied super-resolution shadow imaging (SUSHI) to assess the structure of the extracellular space (ECS) and regular super-resolution microscopy of fluorescently labeled neurons and astrocytes to quantify key neuroanatomical parameters. While the ECS volume fraction (VF) and microanatomic organization of astrocytes remained largely unaffected by the PFA treatment, we detected subtle changes in dendritic spine morphology and observed substantial damage to cell membranes. Our experiments show that PFA application via immersion does not cause a noticeable shrinkage of the ECS in hippocampal brain slices maintained in culture, unlike the situation in transcardially perfused animals in vivo where the ECS typically becomes nearly depleted. Our study outlines an experimental strategy to evaluate the quality and pitfalls of various fixation protocols for the molecular and morphologic preservation of cells and tissues.
Collapse
Affiliation(s)
- Agata Idziak
- Unité Mixte de Recherche 5297, Interdisciplinary Institute for Neuroscience, Centre National de la Recherche Scientifique, University of Bordeaux, Bordeaux F-33000, France
| | - V V G Krishna Inavalli
- Unité Mixte de Recherche 5297, Interdisciplinary Institute for Neuroscience, Centre National de la Recherche Scientifique, University of Bordeaux, Bordeaux F-33000, France
| | - Stéphane Bancelin
- Unité Mixte de Recherche 5297, Interdisciplinary Institute for Neuroscience, Centre National de la Recherche Scientifique, University of Bordeaux, Bordeaux F-33000, France
| | - Misa Arizono
- Unité Mixte de Recherche 5297, Interdisciplinary Institute for Neuroscience, Centre National de la Recherche Scientifique, University of Bordeaux, Bordeaux F-33000, France
- Department of Pharmacology, Kyoto University Graduate School of Medicine/The Hakubi Center for Advanced Research, Kyoto University, Kyoto 606-8501, Japan
| | - U Valentin Nägerl
- Unité Mixte de Recherche 5297, Interdisciplinary Institute for Neuroscience, Centre National de la Recherche Scientifique, University of Bordeaux, Bordeaux F-33000, France
| |
Collapse
|
8
|
Alfadil E, Bradke F. Moving through the crowd. Where are we at understanding physiological axon growth? Semin Cell Dev Biol 2023; 140:63-71. [PMID: 35817655 DOI: 10.1016/j.semcdb.2022.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 01/28/2023]
Abstract
Axon growth enables the rapid wiring of the central nervous system. Understanding this process is a prerequisite to retriggering it under pathological conditions, such as a spinal cord injury, to elicit axon regeneration. The last decades saw progress in understanding the mechanisms underlying axon growth. Most of these studies employed cultured neurons grown on flat surfaces. Only recently studies on axon growth were performed in 3D. In these studies, physiological environments exposed more complex and dynamic aspects of axon development. Here, we describe current views on axon growth and highlight gaps in our knowledge. We discuss how axons interact with the extracellular matrix during development and the role of the growth cone and its cytoskeleton within. Finally, we propose that the time is ripe to study axon growth in a more physiological setting. This will help us uncover the physiologically relevant mechanisms underlying axon growth, and how they can be reactivated to induce axon regeneration.
Collapse
Affiliation(s)
- Eissa Alfadil
- Laboratory of Axon Growth and Regeneration, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Venusberg-Campus 1, Building 99, 53127, Bonn, Germany.
| | - Frank Bradke
- Laboratory of Axon Growth and Regeneration, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Venusberg-Campus 1, Building 99, 53127, Bonn, Germany
| |
Collapse
|
9
|
Kim E, Jeon S, Yang YS, Jin C, Kim JY, Oh YS, Rah JC, Choi H. A Neurospheroid-Based Microrobot for Targeted Neural Connections in a Hippocampal Slice. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208747. [PMID: 36640750 DOI: 10.1002/adma.202208747] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 01/10/2023] [Indexed: 06/17/2023]
Abstract
Functional restoration by the re-establishment of cellular or neural connections remains a major challenge in targeted cell therapy and regenerative medicine. Recent advances in magnetically powered microrobots have shown potential for use in controlled and targeted cell therapy. In this study, a magnetic neurospheroid (Mag-Neurobot) that can form both structural and functional connections with an organotypic hippocampal slice (OHS) is assessed using an ex vivo model as a bridge toward in vivo application. The Mag-Neurobot consists of hippocampal neurons and superparamagnetic nanoparticles (SPIONs); it is precisely and skillfully manipulated by an external magnetic field. Furthermore, the results of patch-clamp recordings of hippocampal neurons indicate that neither the neuronal excitabilities nor the synaptic functions of SPION-loaded cells are significantly affected. Analysis of neural activity propagation using high-density multi-electrode arrays shows that the delivered Mag-Neurobot is functionally connected with the OHS. The applications of this study include functional verification for targeted cell delivery through the characterization of novel synaptic connections and the functionalities of transported and transplanted cells. The success of the Mag-Neurobot opens up new avenues of research and application; it offers a test platform for functional neural connections and neural regenerative processes through cell transplantation.
Collapse
Affiliation(s)
- Eunhee Kim
- IMsystem Co., Ltd., 333, Technojungang-daero, Hyeonpung-eup, Dalseong-gun, Daegu, 42988, Republic of Korea
| | - Sungwoong Jeon
- IMsystem Co., Ltd., 333, Technojungang-daero, Hyeonpung-eup, Dalseong-gun, Daegu, 42988, Republic of Korea
| | - Yoon-Sil Yang
- Emerging Infectious Disease Vaccines Division, National Institute of Food and Drug Safety Evaluation, 187, Osongsaengmyeong 2-ro, Osong-eup, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do, 28159, Republic of Korea
- Korea Brain Research Institute, 61, Cheomdan-ro, Dong-gu, Daegu, 41062, Republic of Korea
| | - Chaewon Jin
- DGIST-ETH Microrobotics Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
| | - Jin-Young Kim
- DGIST-ETH Microrobotics Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
- Department of Robotics and Mechatronics Engineering, DGIST, Daegu, 42988, Republic of Korea
| | - Yong-Seok Oh
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
| | - Jong-Cheol Rah
- Korea Brain Research Institute, 61, Cheomdan-ro, Dong-gu, Daegu, 41062, Republic of Korea
- Department of Brain Sciences, DGIST, Daegu, 42988, Republic of Korea
| | - Hongsoo Choi
- DGIST-ETH Microrobotics Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
- Department of Robotics and Mechatronics Engineering, DGIST, Daegu, 42988, Republic of Korea
- Robotics and Mechatronics Engineering Research Center, DGIST, Daegu, 42988, Republic of Korea
| |
Collapse
|
10
|
Denizot A, Arizono M, Nägerl UV, Berry H, De Schutter E. Control of Ca 2+ signals by astrocyte nanoscale morphology at tripartite synapses. Glia 2022; 70:2378-2391. [PMID: 36097958 PMCID: PMC9825906 DOI: 10.1002/glia.24258] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 07/20/2022] [Accepted: 07/28/2022] [Indexed: 01/11/2023]
Abstract
Much of the Ca2+ activity in astrocytes is spatially restricted to microdomains and occurs in fine processes that form a complex anatomical meshwork, the so-called spongiform domain. A growing body of literature indicates that those astrocytic Ca2+ signals can influence the activity of neuronal synapses and thus tune the flow of information through neuronal circuits. Because of technical difficulties in accessing the small spatial scale involved, the role of astrocyte morphology on Ca2+ microdomain activity remains poorly understood. Here, we use computational tools and idealized 3D geometries of fine processes based on recent super-resolution microscopy data to investigate the mechanistic link between astrocytic nanoscale morphology and local Ca2+ activity. Simulations demonstrate that the nano-morphology of astrocytic processes powerfully shapes the spatio-temporal properties of Ca2+ signals and promotes local Ca2+ activity. The model predicts that this effect is attenuated upon astrocytic swelling, hallmark of brain diseases, which we confirm experimentally in hypo-osmotic conditions. Upon repeated neurotransmitter release events, the model predicts that swelling hinders astrocytic signal propagation. Overall, this study highlights the influence of the complex morphology of astrocytes at the nanoscale and its remodeling in pathological conditions on neuron-astrocyte communication at so-called tripartite synapses, where astrocytic processes come into close contact with pre- and postsynaptic structures.
Collapse
Affiliation(s)
- Audrey Denizot
- Computational Neuroscience UnitOkinawa Institute of Science and TechnologyOnna‐SonJapan
| | - Misa Arizono
- Interdisciplinary Institute for NeuroscienceUniversité de BordeauxBordeauxFrance,Interdisciplinary Institute for NeuroscienceCNRS UMR 5297BordeauxFrance,Department of PharmacologyKyoto University Graduate School of MedicineKyotoJapan
| | - U. Valentin Nägerl
- Interdisciplinary Institute for NeuroscienceUniversité de BordeauxBordeauxFrance,Interdisciplinary Institute for NeuroscienceCNRS UMR 5297BordeauxFrance
| | - Hugues Berry
- LIRIS, UMR5205 CNRSUniv LyonVilleurbanneFrance,INRIAVilleurbanneFrance
| | - Erik De Schutter
- Computational Neuroscience UnitOkinawa Institute of Science and TechnologyOnna‐SonJapan
| |
Collapse
|
11
|
Bissen D, Kracht MK, Foss F, Acker-Palmer A. Expansion microscopy of mouse brain organotypic slice cultures to study protein distribution. STAR Protoc 2022; 3:101507. [PMID: 35776645 PMCID: PMC9249947 DOI: 10.1016/j.xpro.2022.101507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 05/05/2022] [Accepted: 06/08/2022] [Indexed: 11/30/2022] Open
Abstract
Assessing protein distribution with super-resolution in tissue is often complicated and restrictive. Here, we describe a protocol for immunostaining and expansion microscopy imaging of mouse brain organotypic slice cultures. We detail an Imaris analysis workflow to analyze the surface vs intracellular distribution of AMPA receptors at super-resolution during homeostatic plasticity. We have optimized the protocol for brain organotypic slice culture and tested in acute brain slices. This protocol is suitable to study protein distribution under multiple plasticity paradigms. For complete details on the use and execution of this protocol, please refer to Bissen et al. (2021). Enables immunostaining and visualization of epitopes deep within brain slices Utilizes expansion microscopy to increase imaging resolution Optimized for brain organotypic slice cultures and tested in acute brain slices Analysis workflow for protein distribution (surface vs. intracellular pool) using Imaris
Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.
Collapse
Affiliation(s)
- Diane Bissen
- Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Max-von-Laue-Str. 15, 60438, Frankfurt am Main, Germany; Max Planck Institute for Brain Research, Max von Laue Str. 4, 60438 Frankfurt am Main, Germany.
| | - Maximilian Ken Kracht
- Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Max-von-Laue-Str. 15, 60438, Frankfurt am Main, Germany
| | - Franziska Foss
- Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Max-von-Laue-Str. 15, 60438, Frankfurt am Main, Germany
| | - Amparo Acker-Palmer
- Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Max-von-Laue-Str. 15, 60438, Frankfurt am Main, Germany; Max Planck Institute for Brain Research, Max von Laue Str. 4, 60438 Frankfurt am Main, Germany; Cardio-Pulmonary Institute (CPI), Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany.
| |
Collapse
|
12
|
Guérineau NC, Campos P, Le Tissier PR, Hodson DJ, Mollard P. Cell Networks in Endocrine/Neuroendocrine Gland Function. Compr Physiol 2022; 12:3371-3415. [PMID: 35578964 DOI: 10.1002/cphy.c210031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Reproduction, growth, stress, and metabolism are determined by endocrine/neuroendocrine systems that regulate circulating hormone concentrations. All these systems generate rhythms and changes in hormone pulsatility observed in a variety of pathophysiological states. Thus, the output of endocrine/neuroendocrine systems must be regulated within a narrow window of effective hormone concentrations but must also maintain a capacity for plasticity to respond to changing physiological demands. Remarkably most endocrinologists still have a "textbook" view of endocrine gland organization which has emanated from 20th century histological studies on thin 2D tissue sections. However, 21st -century technological advances, including in-depth 3D imaging of specific cell types have vastly changed our knowledge. We now know that various levels of multicellular organization can be found across different glands, that organizational motifs can vary between species and can be modified to enhance or decrease hormonal release. This article focuses on how the organization of cells regulates hormone output using three endocrine/neuroendocrine glands that present different levels of organization and complexity: the adrenal medulla, with a single neuroendocrine cell type; the anterior pituitary, with multiple intermingled cell types; and the pancreas with multiple intermingled cell types organized into distinct functional units. We give an overview of recent methodologies that allow the study of the different components within endocrine systems, particularly their temporal and spatial relationships. We believe the emerging findings about network organization, and its impact on hormone secretion, are crucial to understanding how homeostatic regulation of endocrine axes is carried out within endocrine organs themselves. © 2022 American Physiological Society. Compr Physiol 12:3371-3415, 2022.
Collapse
Affiliation(s)
| | - Pauline Campos
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Paul R Le Tissier
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, Scotland, UK
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Edgbaston, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK.,COMPARE University of Birmingham and University of Nottingham Midlands, UK.,Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Patrice Mollard
- IGF, University of Montpellier, CNRS, INSERM, Montpellier, France
| |
Collapse
|
13
|
Alternative Brain Slice-on-a-Chip for Organotypic Culture and Effective Fluorescence Injection Testing. Int J Mol Sci 2022; 23:ijms23052549. [PMID: 35269696 PMCID: PMC8910551 DOI: 10.3390/ijms23052549] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 11/22/2022] Open
Abstract
Mouse brain slices are one of the most common models to study brain development and functioning, increasing the number of study models that integrate microfluidic systems for hippocampal slice cultures. This report presents an alternative brain slice-on-a-chip, integrating an injection system inside the chip to dispense a fluorescent dye for long-term monitoring. Hippocampal slices have been cultured inside these chips, observing fluorescence signals from living cells, maintaining the cytoarchitecture of the slices. Having fluorescence images of biological samples inside the chip demonstrates the effectiveness of the staining process using the injection method avoiding leaks or biological contamination. The technology developed in this study presents a significant improvement in the local administration of reagents within a brain slice-on-a-chip system, which could be a suitable option for organotypic cultures in a microfluidic chip acting as a highly effective bioreactor.
Collapse
|
14
|
Nogueira GO, Garcez PP, Bardy C, Cunningham MO, Sebollela A. Modeling the Human Brain With ex vivo Slices and in vitro Organoids for Translational Neuroscience. Front Neurosci 2022; 16:838594. [PMID: 35281505 PMCID: PMC8908416 DOI: 10.3389/fnins.2022.838594] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 01/27/2022] [Indexed: 01/02/2023] Open
Affiliation(s)
- Giovanna O. Nogueira
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Patricia P. Garcez
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Cedric Bardy
- Laboratory for Human Neurophysiology and Genetics, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, Australia
- Flinders Health and Medical Research Institute, Flinders University, Adelaide, SA, Australia
| | - Mark O. Cunningham
- Discipline of Physiology, School of Medicine, Trinity College Dublin, Dublin 2, Ireland
| | - Adriano Sebollela
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
- *Correspondence: Adriano Sebollela
| |
Collapse
|
15
|
Steiner K, Humpel C. Microcontact Printing of Cholinergic Neurons in Organotypic Brain Slices. Front Neurol 2021; 12:775621. [PMID: 34867765 PMCID: PMC8636044 DOI: 10.3389/fneur.2021.775621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 10/07/2021] [Indexed: 01/29/2023] Open
Abstract
Alzheimer's disease is a severe neurodegenerative disorder of the brain, characterized by beta-amyloid plaques, tau pathology, and cell death of cholinergic neurons, resulting in loss of memory. The reasons for the damage of the cholinergic neurons are not clear, but the nerve growth factor (NGF) is the most potent trophic factor to support the survival of these neurons. In the present study we aim to microprint NGF onto semipermeable 0.4 μm pore membranes and couple them with organotypic brain slices of the basal nucleus of Meynert and to characterize neuronal survival and axonal growth. The brain slices were prepared from postnatal day 10 wildtype mice (C57BL6), cultured on membranes for 2–6 weeks, stained, and characterized for choline acetyltransferase (ChAT). The NGF was microcontact printed in 28 lines, each with 35 μm width, 35 μm space between them, and with a length of 8 mm. As NGF alone could not be printed on the membranes, NGF was embedded into collagen hydrogels and the brain slices were placed at the center of the microprints and the cholinergic neurons that survived. The ChAT+ processes were found to grow along with the NGF microcontact prints, but cells also migrated. Within the brain slices, some form of re-organization along the NGF microcontact prints occurred, especially the glial fibrillary acidic protein (GFAP)+ astrocytes. In conclusion, we provided a novel innovative microcontact printing technique on semipermeable membranes which can be coupled with brain slices. Collagen was used as a loading substance and allowed the microcontact printing of nearly any protein of interest.
Collapse
|
16
|
Panattoni G, Amoriello R, Memo C, Thalhammer A, Ballerini C, Ballerini L. Diverse inflammatory threats modulate astrocytes Ca 2+ signaling via connexin43 hemichannels in organotypic spinal slices. Mol Brain 2021; 14:159. [PMID: 34696792 PMCID: PMC8547100 DOI: 10.1186/s13041-021-00868-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/15/2021] [Indexed: 02/07/2023] Open
Abstract
Neuroinflammation is an escalation factor shared by a vast range of central nervous system (CNS) pathologies, from neurodegenerative diseases to neuropsychiatric disorders. CNS immune status emerges by the integration of the responses of resident and not resident cells, leading to alterations in neural circuits functions. To explore spinal cord astrocyte reactivity to inflammatory threats we focused our study on the effects of local inflammation in a controlled micro-environment, the organotypic spinal slices, developed from the spinal cord of mouse embryos. These organ cultures represent a complex in vitro model where sensory-motor cytoarchitecture, synaptic properties and spinal cord resident cells, are retained in a 3D fashion and we recently exploit these cultures to model two diverse immune conditions in the CNS, involving different inflammatory networks and products. Here, we specifically focus on the tuning of calcium signaling in astrocytes by these diverse types of inflammation and we investigate the mechanisms which modulate intracellular calcium release and its spreading among astrocytes in the inflamed environment. Organotypic spinal cord slices are cultured for two or three weeks in vitro (WIV) and exposed for 6 h to a cocktail of cytokines (CKs), composed by tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1 β) and granulocyte macrophage-colony stimulating factor (GM-CSF), or to lipopolysaccharide (LPS). By live calcium imaging of the ventral horn, we document an increase in active astrocytes and in the occurrence of spontaneous calcium oscillations displayed by these cells when exposed to each inflammatory threat. Through several pharmacological treatments, we demonstrate that intracellular calcium sources and the activation of connexin 43 (Cx43) hemichannels have a pivotal role in increasing calcium intercellular communication in both CKs and LPS conditions, while the Cx43 gap junction communication is apparently reduced by the inflammatory treatments.
Collapse
Affiliation(s)
- Giulia Panattoni
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy
| | - Roberta Amoriello
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy.,Dipartimento di Medicina Sperimentale e Clinica, University of Florence, 50139, Florence, Italy
| | - Christian Memo
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy
| | - Agnes Thalhammer
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy
| | - Clara Ballerini
- Dipartimento di Medicina Sperimentale e Clinica, University of Florence, 50139, Florence, Italy.
| | - Laura Ballerini
- International School for Advanced Studies (SISSA/ISAS), 34136, Trieste, Italy.
| |
Collapse
|
17
|
Michaelson SD, Müller TM, Bompolaki M, Miranda Tapia AP, Villarroel HS, Mackay JP, Balogun PJ, Urban JH, Colmers WF. Long-Lived Organotypic Slice Culture Model of the Rat Basolateral Amygdala. Curr Protoc 2021; 1:e267. [PMID: 34670009 DOI: 10.1002/cpz1.267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Organotypic slice cultures (OTCs) have been employed in the laboratory since the early 1980s and have proved to be useful for the study of a number of neural systems. Our recent work focuses on the development of behavioral stress resilience induced by repeated daily injections of neuropeptide Y into the basolateral amygdala (BLA). Resilience develops over weeks, persisting to 8 weeks. To unravel the cellular mechanisms underlying neuropeptide Y-induced stress resilience we developed in vitro OTCs of the BLA. Here, we provide an optimized protocol that consistently yields viable and healthy OTCs containing the BLA and surrounding tissue using the interface method, prepared with slices taken from postnatal (P) day 14 rats. We explain key points to optimizing tissue viability and discuss mitigation or avoidance of pitfalls that can arise to aid in successful implementation of this technique. We show that principal neurons in BLA OTCs (8 weeks in vitro = equivalent postnatal day 70) develop into networks that are electrophysiologically very similar to those from acute slices obtained from older rats (P70) and respond to pharmacological treatments in a comparable way. Furthermore, we highlight how these cultures be used to further understand the molecular, cellular, and circuit-level neuropathophysiological changes underlying stress disorders. BLA OTCs provide long-term physiological and pharmacological results whose predictions were borne out in vivo, supporting the validity of the BLA OTC as a model to unravel BLA neurocircuitry. Recent preliminary results also support the successful application of this approach to preparing long-lived OTCs of BLA and neocortex from mice. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Organotypic slice culture Support Protocol 1: Changing medium Support Protocol 2: Drug incubations Basic Protocol 2: Excision of OTC slices from inserts Support Protocol 3: Fixation of slices.
Collapse
Affiliation(s)
- Sheldon D Michaelson
- Department of Pharmacology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Taylor M Müller
- Department of Pharmacology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Maria Bompolaki
- Center for the Neurobiology of Stress Resilience and Psychiatric Disorders, Chicago Medical School/Rosalind Franklin University of Medicine & Science, North Chicago, Illinois
| | - Ana Pamela Miranda Tapia
- Department of Pharmacology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Heika Silveira Villarroel
- Department of Pharmacology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - James P Mackay
- Department of Pharmacology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Pauline J Balogun
- Department of Pharmacology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Janice H Urban
- Center for the Neurobiology of Stress Resilience and Psychiatric Disorders, Chicago Medical School/Rosalind Franklin University of Medicine & Science, North Chicago, Illinois
| | - William F Colmers
- Department of Pharmacology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
18
|
Brandalise F, Carta S, Leone R, Helmchen F, Holtmaat A, Gerber U. Dendritic Branch-constrained N-Methyl-d-Aspartate Receptor-mediated Spikes Drive Synaptic Plasticity in Hippocampal CA3 Pyramidal Cells. Neuroscience 2021; 489:57-68. [PMID: 34634424 DOI: 10.1016/j.neuroscience.2021.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 09/27/2021] [Accepted: 10/03/2021] [Indexed: 10/20/2022]
Abstract
N-methyl-d-aspartate receptor-mediated ( spikes can be causally linked to the induction of synaptic long-term potentiation (LTP) in hippocampal and cortical pyramidal cells. However, it is unclear if they regulate plasticity at a local or global scale in the dendritic tree. Here, we used dendritic patch-clamp recordings and calcium imaging to investigate the integrative properties of single dendrites of hippocampal CA3 cells. We show that local hyperpolarization of a single dendritic segment prevents NMDA spikes, their associated calcium transients, as well as LTP in a branch-specific manner. This result provides direct, causal evidence that the single dendritic branch can operate as a functional unit in regulating CA3 pyramidal cell plasticity.
Collapse
Affiliation(s)
- Federico Brandalise
- Department of Basic Neurosciences and the Center for Neuroscience, Centre Médical Universitaire (CMU), University of Geneva, 1211 Geneva, Switzerland; Former affiliation(b).
| | - Stefano Carta
- Brain Research Institute and Neuroscience Center Zurich, University of Zurich, CH-8057 Zurich, Switzerland
| | - Roberta Leone
- Department of Basic Neurosciences and the Center for Neuroscience, Centre Médical Universitaire (CMU), University of Geneva, 1211 Geneva, Switzerland
| | - Fritjof Helmchen
- Brain Research Institute and Neuroscience Center Zurich, University of Zurich, CH-8057 Zurich, Switzerland
| | - Anthony Holtmaat
- Department of Basic Neurosciences and the Center for Neuroscience, Centre Médical Universitaire (CMU), University of Geneva, 1211 Geneva, Switzerland
| | | |
Collapse
|
19
|
Slice Culture Modeling of CNS Viral Infection. Methods Mol Biol 2021. [PMID: 34033080 DOI: 10.1007/978-1-0716-1437-2_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The complexity of the central nervous system (CNS) is not recapitulated in cell culture models. Thin slicing and subsequent culture of CNS tissue has become a valued means to study neuronal and glial biology within the context of the physiologically relevant tissue milieu. Modern membrane-interface slice culturing methodology allows for straightforward access to both CNS tissue and feeding medium, enabling experimental manipulations and analyses that would otherwise be impossible in vivo. CNS slices can be successfully maintained in culture for up to several weeks for investigation of evolving pathology and long-term intervention in models of chronic neurologic disease.Herein, membrane-interface slice culture models for studying viral encephalitis and myelitis are detailed, with emphasis on the use of these models for investigation of pathogenesis and evaluation of novel treatment strategies. We describe techniques to (1) generate brain and spinal cord slices from rodent donors, (2) virally infect slices, (3) monitor viral replication, (4) assess virally induced injury/apoptosis, (5) characterize "CNS-specific" cytokine production, and, (6) treat slices with cytokines/pharmaceuticals. Although our focus is on CNS viral infection, we anticipate that the described methods can be adapted to address a wide range of investigations within the fields of neuropathology, neuroimmunology, and neuropharmacology.
Collapse
|
20
|
Hickmott RA, Bosakhar A, Quezada S, Barresi M, Walker DW, Ryan AL, Quigley A, Tolcos M. The One-Stop Gyrification Station - Challenges and New Technologies. Prog Neurobiol 2021; 204:102111. [PMID: 34166774 DOI: 10.1016/j.pneurobio.2021.102111] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/31/2021] [Accepted: 06/18/2021] [Indexed: 12/12/2022]
Abstract
The evolution of the folded cortical surface is an iconic feature of the human brain shared by a subset of mammals and considered pivotal for the emergence of higher-order cognitive functions. While our understanding of the neurodevelopmental processes involved in corticogenesis has greatly advanced over the past 70 years of brain research, the fundamental mechanisms that result in gyrification, along with its originating cytoarchitectural location, remain largely unknown. This review brings together numerous approaches to this basic neurodevelopmental problem, constructing a narrative of how various models, techniques and tools have been applied to the study of gyrification thus far. After a brief discussion of core concepts and challenges within the field, we provide an analysis of the significant discoveries derived from the parallel use of model organisms such as the mouse, ferret, sheep and non-human primates, particularly with regard to how they have shaped our understanding of cortical folding. We then focus on the latest developments in the field and the complementary application of newly emerging technologies, such as cerebral organoids, advanced neuroimaging techniques, and atomic force microscopy. Particular emphasis is placed upon the use of novel computational and physical models in regard to the interplay of biological and physical forces in cortical folding.
Collapse
Affiliation(s)
- Ryan A Hickmott
- School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, 3083, Australia; BioFab3D@ACMD, St Vincent's Hospital Melbourne, Fitzroy, VIC, 3065, Australia
| | - Abdulhameed Bosakhar
- School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, 3083, Australia
| | - Sebastian Quezada
- School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, 3083, Australia
| | - Mikaela Barresi
- School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, 3083, Australia
| | - David W Walker
- School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, 3083, Australia
| | - Amy L Ryan
- Hastings Centre for Pulmonary Research, Department of Pulmonary, Critical Care and Sleep Medicine, USC Keck School of Medicine, University of Southern California, CA, USA and Department of Stem Cell and Regenerative Medicine, University of Southern California, CA, 90033, USA
| | - Anita Quigley
- School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, 3083, Australia; BioFab3D@ACMD, St Vincent's Hospital Melbourne, Fitzroy, VIC, 3065, Australia; School of Engineering, RMIT University, Melbourne, VIC, 3000, Australia; Department of Medicine, University of Melbourne, St Vincent's Hospital, Fitzroy, VIC, 3065, Australia; ARC Centre of Excellence in Electromaterials Science, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Mary Tolcos
- School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, 3083, Australia.
| |
Collapse
|
21
|
Preparation and Culture of Organotypic Hippocampal Slices for the Analysis of Brain Metastasis and Primary Brain Tumor Growth. Methods Mol Biol 2021. [PMID: 33742394 DOI: 10.1007/978-1-0716-1350-4_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/02/2023]
Abstract
Brain metastasis is a major challenge for therapy and defines the end stage of tumor progression with a very limited patients' prognosis. Experimental setups that faithfully mimic these processes are necessary to understand the mechanism of brain metastasis and to develop new improved therapeutic strategies. Here, we describe an in vitro model, which closely resembles the in vivo situation. Organotypic hippocampal brain slice cultures (OHSCs) prepared from 3- to 8-day-old mice are well suited for neuro-oncology research including brain metastasis. The original morphology is preserved in OHSCs even after culture periods of several days to weeks. Tumor cells or cells of metastatic origin can be seeded onto OHSCs to evaluate micro-tumor formation, tumor cell invasion, or treatment response. We describe preparation and culture of OHSCs including the seeding of tumor cells. Finally, we show examples of how to treat the OHSCs for life-dead or immunohistochemical staining.
Collapse
|
22
|
Saleheen A, Acharyya D, Prosser RA, Baker CA. A microfluidic bubble perfusion device for brain slice culture. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2021; 13:1364-1373. [PMID: 33644791 DOI: 10.1039/d0ay02291h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Ex vivo brain slice cultures are utilized as analytical models for studying neurophysiology. Common approaches to maintaining slice cultures include roller tube and membrane interface techniques. The rise of organ-on-chip technologies has demonstrated the value of microfluidic perfusion culture systems for sampling and analysis of complex biology under well-controlled in vitro or ex vivo conditions. A number of approaches to microfluidic brain slice culture have been developed, however these typically involve complex design, fabrication, or operational parameters in order to meet the high oxygen demands of brain slices. Here, we present proof-of-principle for a novel approach to microfluidic brain slice culture. In this system, which we term a microfluidic bubble perfusion device, principles of droplet microfluidics were employed to generate droplets of perfusion media dispersed between bubbles of carbogen gas, and brain tissue slices were perfused with the resulting monodispersed droplets and bubbles. The challenge of tissue immobilization in the flow system was addressed using a two-part cytocompatible carbohydrate-based tissue adhesive. Best practices are discussed for perfusion chamber designs that maintain segmented flow throughout the course of perfusion. Control of droplet and bubble volumes was possible across the range of ca. 4-15 μL, bubble generation frequency was well controlled in the range ca. 1-7 bubbles per min, and bubble duty cycle was well controlled across the range ca. 20-80%. Murine hypothalamic tissue slices containing the suprachiasmatic nuclei were successfully maintained for durations of 8-10 hours, with tissue remaining viable for the duration of perfusion as assessed by Ca2+ imaging and propidium iodide (PI) staining.
Collapse
Affiliation(s)
- Amirus Saleheen
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA
| | | | | | | |
Collapse
|
23
|
Arizono M, Inavalli VVGK, Bancelin S, Fernández-Monreal M, Nägerl UV. Super-resolution shadow imaging reveals local remodeling of astrocytic microstructures and brain extracellular space after osmotic challenge. Glia 2021; 69:1605-1613. [PMID: 33710691 DOI: 10.1002/glia.23995] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 02/26/2021] [Accepted: 03/03/2021] [Indexed: 12/12/2022]
Abstract
The extracellular space (ECS) plays a central role in brain physiology, shaping the time course and spread of neurochemicals, ions, and nutrients that ensure proper brain homeostasis and neuronal communication. Astrocytes are the most abundant type of glia cell in the brain, whose processes densely infiltrate the brain's parenchyma. As astrocytes are highly sensitive to changes in osmotic pressure, they are capable of exerting a potent physiological influence on the ECS. However, little is known about the spatial distribution and temporal dynamics of the ECS that surrounds astrocytes, owing mostly to a lack of appropriate techniques to visualize the ECS in live brain tissue. Mitigating this technical limitation, we applied the recent SUper-resolution SHadow Imaging technique (SUSHI) to astrocyte-labeled organotypic hippocampal brain slices, which allowed us to concurrently image the complex morphology of astrocytes and the ECS with unprecedented spatial resolution in a live experimental setting. Focusing on ring-like astrocytic microstructures in the spongiform domain, we found them to enclose sizable pools of interstitial fluid and cellular structures like dendritic spines. Upon experimental osmotic challenge, these microstructures remodeled and swelled up at the expense of the pools, effectively increasing the physical interface between astrocytic and cellular structures. Our study reveals novel facets of the dynamic microanatomical relationships between astrocytes, neuropil, and the ECS in living brain tissue, which could be of functional relevance for neuron-glia communication in a variety of (patho)physiological settings, for example, LTP induction, epileptic seizures or acute ischemic stroke, where osmotic disturbances are known to occur.
Collapse
Affiliation(s)
- Misa Arizono
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - V V G Krishna Inavalli
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - Stéphane Bancelin
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - Mónica Fernández-Monreal
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France.,Bordeaux Imaging Center, UMS 3420, CNRS, Université de Bordeaux, US4 INSERM, Bordeaux, France
| | - U Valentin Nägerl
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| |
Collapse
|
24
|
Preparation of Rat Organotypic Hippocampal Slice Cultures Using the Membrane-Interface Method. Methods Mol Biol 2021; 2188:243-257. [PMID: 33119855 DOI: 10.1007/978-1-0716-0818-0_12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cultured hippocampal slices from rodents, in which the architecture and functional properties of the hippocampal network are largely preserved, have proved to be a powerful substrate for studying healthy and pathological neuronal mechanisms. Here, we delineate the membrane-interface method for maintaining organotypic slices in culture for several weeks. The protocol includes procedures for dissecting hippocampus from rat brain, and collecting slices using a vibratome. This method provides the experimenter with easy access to both the brain tissue and culture medium, which facilitates genetic and pharmacological manipulations and enables experiments that incorporate imaging and electrophysiology. The method is generally applicable to rats of different ages, and to different brain regions, and can be modified for culture of slices from other species including mice.
Collapse
|
25
|
AlaylioĞlu M, Dursun E, Yilmazer S, Ak DG. A Bridge Between in vitro and in vivo Studies in Neuroscience: Organotypic Brain Slice Cultures. ACTA ACUST UNITED AC 2020; 57:333-337. [PMID: 33354128 DOI: 10.29399/npa.26139] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 05/26/2020] [Indexed: 12/25/2022]
Abstract
In vitro and in vivo models are efficiently used systems in neuroscience research to study the brain in normal or pathological conditions. There are many advantages to these systems, yet they also have significant limitations. In vitro cell cultures offer the opportunity to investigate the cell basics or primary response of a cell population against any treatment. However, these models do not always predict in vivo behavior. In vivo animal studies constitute the most realistic platform for research and therapeutic approaches, yet they are laborious, open to secondary complications and painful or stressful for the animals from an ethical point of view. Organotypic brain slice cultures provide an in vivo-like environment since they maintain three-dimensional cytoarchitecture of the brain thus enable to study many cell types in one system and allow precise control of the microenvironment. In this review, we will focus on the history and key features of organotypic brain slice cultures as well as its preparation.
Collapse
Affiliation(s)
- Merve AlaylioĞlu
- Brain and Neurodegenerative Disorders Research Laboratory, Department of Medical Biology, Cerrahpaşa Faculty of Medicine, İstanbul University-Cerrahpaşa, İstanbul, Turkey
| | - Erdinç Dursun
- Brain and Neurodegenerative Disorders Research Laboratory, Department of Medical Biology, Cerrahpaşa Faculty of Medicine, İstanbul University-Cerrahpaşa, İstanbul, Turkey.,Department of Neuroscience, Institute of Neurological Sciences, İstanbul University-Cerrahpaşa, İstanbul, Turkey
| | - Selma Yilmazer
- Department of Medical Biology, School of Medicine, Altınbaş University, İstanbul, Turkey
| | - Duygu Gezen Ak
- Brain and Neurodegenerative Disorders Research Laboratory, Department of Medical Biology, Cerrahpaşa Faculty of Medicine, İstanbul University-Cerrahpaşa, İstanbul, Turkey
| |
Collapse
|
26
|
Imig C, López-Murcia FJ, Maus L, García-Plaza IH, Mortensen LS, Schwark M, Schwarze V, Angibaud J, Nägerl UV, Taschenberger H, Brose N, Cooper BH. Ultrastructural Imaging of Activity-Dependent Synaptic Membrane-Trafficking Events in Cultured Brain Slices. Neuron 2020; 108:843-860.e8. [PMID: 32991831 PMCID: PMC7736621 DOI: 10.1016/j.neuron.2020.09.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 07/03/2020] [Accepted: 09/01/2020] [Indexed: 12/15/2022]
Abstract
Electron microscopy can resolve synapse ultrastructure with nanometer precision, but the capture of time-resolved, activity-dependent synaptic membrane-trafficking events has remained challenging, particularly in functionally distinct synapses in a tissue context. We present a method that combines optogenetic stimulation-coupled cryofixation ("flash-and-freeze") and electron microscopy to visualize membrane trafficking events and synapse-state-specific changes in presynaptic vesicle organization with high spatiotemporal resolution in synapses of cultured mouse brain tissue. With our experimental workflow, electrophysiological and "flash-and-freeze" electron microscopy experiments can be performed under identical conditions in artificial cerebrospinal fluid alone, without the addition of external cryoprotectants, which are otherwise needed to allow adequate tissue preservation upon freezing. Using this approach, we reveal depletion of docked vesicles and resolve compensatory membrane recycling events at individual presynaptic active zones at hippocampal mossy fiber synapses upon sustained stimulation.
Collapse
Affiliation(s)
- Cordelia Imig
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany.
| | - Francisco José López-Murcia
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Lydia Maus
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Georg August University School of Science, Georg August University Göttingen, 37073 Göttingen, Germany
| | - Inés Hojas García-Plaza
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, 37077 Göttingen, Germany
| | - Lena Sünke Mortensen
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Manuela Schwark
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Valentin Schwarze
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Julie Angibaud
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000 Bordeaux, France
| | - U Valentin Nägerl
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000 Bordeaux, France
| | - Holger Taschenberger
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Nils Brose
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" University of Göttingen, 37073 Göttingen, Germany.
| | - Benjamin H Cooper
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany.
| |
Collapse
|
27
|
Nikolakopoulou P, Rauti R, Voulgaris D, Shlomy I, Maoz BM, Herland A. Recent progress in translational engineered in vitro models of the central nervous system. Brain 2020; 143:3181-3213. [PMID: 33020798 PMCID: PMC7719033 DOI: 10.1093/brain/awaa268] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 06/17/2020] [Accepted: 06/21/2020] [Indexed: 02/07/2023] Open
Abstract
The complexity of the human brain poses a substantial challenge for the development of models of the CNS. Current animal models lack many essential human characteristics (in addition to raising operational challenges and ethical concerns), and conventional in vitro models, in turn, are limited in their capacity to provide information regarding many functional and systemic responses. Indeed, these challenges may underlie the notoriously low success rates of CNS drug development efforts. During the past 5 years, there has been a leap in the complexity and functionality of in vitro systems of the CNS, which have the potential to overcome many of the limitations of traditional model systems. The availability of human-derived induced pluripotent stem cell technology has further increased the translational potential of these systems. Yet, the adoption of state-of-the-art in vitro platforms within the CNS research community is limited. This may be attributable to the high costs or the immaturity of the systems. Nevertheless, the costs of fabrication have decreased, and there are tremendous ongoing efforts to improve the quality of cell differentiation. Herein, we aim to raise awareness of the capabilities and accessibility of advanced in vitro CNS technologies. We provide an overview of some of the main recent developments (since 2015) in in vitro CNS models. In particular, we focus on engineered in vitro models based on cell culture systems combined with microfluidic platforms (e.g. 'organ-on-a-chip' systems). We delve into the fundamental principles underlying these systems and review several applications of these platforms for the study of the CNS in health and disease. Our discussion further addresses the challenges that hinder the implementation of advanced in vitro platforms in personalized medicine or in large-scale industrial settings, and outlines the existing differentiation protocols and industrial cell sources. We conclude by providing practical guidelines for laboratories that are considering adopting organ-on-a-chip technologies.
Collapse
Affiliation(s)
- Polyxeni Nikolakopoulou
- AIMES, Center for the Advancement of Integrated Medical and Engineering Sciences, Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Rossana Rauti
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Dimitrios Voulgaris
- Division of Micro and Nanosystems, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Iftach Shlomy
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Ben M Maoz
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- The Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Anna Herland
- AIMES, Center for the Advancement of Integrated Medical and Engineering Sciences, Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
- Division of Micro and Nanosystems, KTH Royal Institute of Technology, Stockholm, Sweden
| |
Collapse
|
28
|
Drexler B, Grenz J, Grasshoff C, Antkowiak B. Allopregnanolone Enhances GABAergic Inhibition in Spinal Motor Networks. Int J Mol Sci 2020; 21:ijms21197399. [PMID: 33036451 PMCID: PMC7582554 DOI: 10.3390/ijms21197399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/28/2020] [Accepted: 10/01/2020] [Indexed: 11/16/2022] Open
Abstract
The neurosteroid allopregnanolone (ALLO) causes unconsciousness by allosteric modulation of γ-aminobutyric acid type A (GABAA) receptors, but its actions on the spinal motor networks are unknown. We are therefore testing the hypothesis that ALLO attenuates the action potential firing of spinal interneurons and motoneurons predominantly via enhancing tonic, but not synaptic GABAergic inhibition. We used video microscopy to assess motoneuron-evoked muscle activity in organotypic slice cultures prepared from the spinal cord and muscle tissue. Furthermore, we monitored GABAA receptor-mediated currents by performing whole-cell voltage-clamp recordings. We found that ALLO (100 nM) reduced the action potential firing of spinal interneurons by 27% and that of α-motoneurons by 33%. The inhibitory effects of the combination of propofol (1 µM) and ALLO on motoneuron-induced muscle contractions were additive. Moreover, ALLO evoked a tonic, GABAA receptor-mediated current (amplitude: 41 pA), without increasing phasic GABAergic transmission. Since we previously showed that at a clinically relevant concentration of 1 µM propofol enhanced phasic, but not tonic GABAergic inhibition, we conclude that ALLO and propofol target distinct subpopulations of GABAA receptors. These findings provide first evidence that the combined application of ALLO and propofol may help to reduce intraoperative movements and undesired side effects that are frequently observed under total intravenous anesthesia.
Collapse
|
29
|
Abstract
Many of the toxic compounds that are at large in the environment represent a risk to our neuronal functions. Chemicals may have a direct or indirect effect on the nervous system and they may interfere with general biochemical properties or specific neuronal structures and processes. In this review, a brief presentation of the major neurotoxicological targets is given, together with a discussion of some aspects of the use of different in vitro models for screening purposes and mechanistic studies. It is believed that in vitro methods offer special opportunities for the development of new neurotoxicological assays, and that this development will mainly involve cultured model systems. Therefore, a presentation of nerve and glia tissue culture methods is given, followed by an overview of how information on the action of mercury and mercurials, excitotoxins and acrylamide has been obtained through the use of cultured cell models. It is concluded that the developmental potential in cell neurotoxicology lies within the areas of separation and identification of cells representative for different structures in the nervous system, co-cultivation of different cell types, in vivo/in vitro (ex vivo) procedures, chemically defined media, metabolic competent cultures of human cells and improved physiological conditions for cultivation and exposure.
Collapse
Affiliation(s)
- Erik Walum
- Unit of Neurochemistry and Neurotoxicology, University of Stockholm, S-106 91 Stockholm, Sweden
| | - Elisabeth Hansson
- Institute of Neurobiology, University of Göteborg, P.O. Box 33031, S-400 33 Göteborg, Sweden
| | - Alan L. Harvey
- Department of Physiology and Pharmacology, University of Strathclyde, Glasgow G1 1XW, UK
| |
Collapse
|
30
|
Lin C, Calzarossa C, Fernandez-Zafra T, Liu J, Li X, Ekblad-Nordberg Å, Vazquez-Juarez E, Codeluppi S, Holmberg L, Lindskog M, Uhlén P, Åkesson E. Human ex vivo spinal cord slice culture as a useful model of neural development, lesion, and allogeneic neural cell therapy. Stem Cell Res Ther 2020; 11:320. [PMID: 32727554 PMCID: PMC7390865 DOI: 10.1186/s13287-020-01771-y] [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: 02/27/2020] [Revised: 05/18/2020] [Accepted: 06/12/2020] [Indexed: 12/14/2022] Open
Abstract
Background There are multiple promising treatment strategies for central nervous system trauma and disease. However, to develop clinically potent and safe treatments, models of human-specific conditions are needed to complement in vitro and in vivo animal model-based studies. Methods We established human brain stem and spinal cord (cross- and longitudinal sections) organotypic cultures (hOCs) from first trimester tissues after informed consent by donor and ethical approval by the Regional Human Ethics Committee, Stockholm (lately referred to as Swedish Ethical Review Authority), and The National Board of Health and Welfare, Sweden. We evaluated the stability of hOCs with a semi-quantitative hOC score, immunohistochemistry, flow cytometry, Ca2+ signaling, and electrophysiological analysis. We also applied experimental allogeneic human neural cell therapy after injury in the ex vivo spinal cord slices. Results The spinal cord hOCs presented relatively stable features during 7–21 days in vitro (DIV) (except a slightly increased cell proliferation and activated glial response). After contusion injury performed at 7 DIV, a significant reduction of the hOC score, increase of the activated caspase-3+ cell population, and activated microglial populations at 14 days postinjury compared to sham controls were observed. Such elevation in the activated caspase-3+ population and activated microglial population was not observed after allogeneic human neural cell therapy. Conclusions We conclude that human spinal cord slice cultures have potential for future structural and functional studies of human spinal cord development, injury, and treatment strategies.
Collapse
Affiliation(s)
- Chenhong Lin
- Department of Neurobiology, Care Sciences and Society, Div. of Neurogeriatrics, Karolinska Institutet, Stockholm, Sweden
| | - Cinzia Calzarossa
- Department of Neurobiology, Care Sciences and Society, Div. of Neurogeriatrics, Karolinska Institutet, Stockholm, Sweden.,Department of Neurology and Laboratory of Neuroscience, Università degli Studi diMilan, Milan, Italy
| | - Teresa Fernandez-Zafra
- Division of Molecular Neurobiology, Departmentof Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Jia Liu
- Department of Neurobiology, Care Sciences and Society, Div. of Neurogeriatrics, Karolinska Institutet, Stockholm, Sweden.,Department of Neurology, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China
| | - Xiaofei Li
- Department of Neurobiology, Care Sciences and Society, Div. of Neurogeriatrics, Karolinska Institutet, Stockholm, Sweden
| | - Åsa Ekblad-Nordberg
- Department of Clinical Science, Intervention and Technology, Div. of Obstetrics and Gynecology, Karolinska Institutet, Stockholm, Sweden
| | - Erika Vazquez-Juarez
- Department of Neurobiology, Care Sciences and Society, Div. of Neurogeriatrics, Karolinska Institutet, Stockholm, Sweden
| | - Simone Codeluppi
- Division of Molecular Neurobiology, Departmentof Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Lena Holmberg
- Department of Neurobiology, Care Sciences and Society, Div. of Neurogeriatrics, Karolinska Institutet, Stockholm, Sweden
| | - Maria Lindskog
- Department of Neurobiology, Care Sciences and Society, Div. of Neurogeriatrics, Karolinska Institutet, Stockholm, Sweden
| | - Per Uhlén
- Division of Molecular Neurobiology, Departmentof Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Elisabet Åkesson
- Department of Neurobiology, Care Sciences and Society, Div. of Neurogeriatrics, Karolinska Institutet, Stockholm, Sweden. .,The R&D Unit, Stockholms Sjukhem, Stockholm, Sweden.
| |
Collapse
|
31
|
Structural basis of astrocytic Ca 2+ signals at tripartite synapses. Nat Commun 2020; 11:1906. [PMID: 32312988 PMCID: PMC7170846 DOI: 10.1038/s41467-020-15648-4] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 03/19/2020] [Indexed: 02/07/2023] Open
Abstract
Astrocytic Ca2+ signals can be fast and local, supporting the idea that astrocytes have the ability to regulate single synapses. However, the anatomical basis of such specific signaling remains unclear, owing to difficulties in resolving the spongiform domain of astrocytes where most tripartite synapses are located. Using 3D-STED microscopy in living organotypic brain slices, we imaged the spongiform domain of astrocytes and observed a reticular meshwork of nodes and shafts that often formed loop-like structures. These anatomical features were also observed in acute hippocampal slices and in barrel cortex in vivo. The majority of dendritic spines were contacted by nodes and their sizes were correlated. FRAP experiments and Ca2+ imaging showed that nodes were biochemical compartments and Ca2+ microdomains. Mapping astrocytic Ca2+ signals onto STED images of nodes and dendritic spines showed they were associated with individual synapses. Here, we report on the nanoscale organization of astrocytes, identifying nodes as a functional astrocytic component of tripartite synapses that may enable synapse-specific communication between neurons and astrocytes. Astrocytic Ca2+ signals can be fast and local, supporting the idea that astrocytes have the ability to regulate single synapses. Here, the authors report the organization of astrocytes at nanoscale level and identify nodes as a functional astrocytic component of tripartite synapses.
Collapse
|
32
|
Grüßer L, Blaumeiser-Debarry R, Rossaint R, Krings M, Kremer B, Höllig A, Coburn M. A 6-Step Approach to Gain Higher Quality Results From Organotypic Hippocampal Brain Slices in a Traumatic Brain Injury Model. Basic Clin Neurosci 2020; 10:485-498. [PMID: 32284838 PMCID: PMC7149959 DOI: 10.32598/bcn.9.10.235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 09/27/2018] [Accepted: 03/22/2019] [Indexed: 01/20/2023] Open
Abstract
Introduction Organotypic Hippocampal Brain Slices (OHBS) provide an advantageous alternative to in vivo models to scrutinize Traumatic Brain Injury (TBI). We followed a well-established TBI protocol, but noticed that several factors may influence the results in such a setup. Here, we describe a structured approach to generate more comparable results and discuss why specific eligibility criteria should be applied. Methods We defined necessary checkpoints and developed inclusion and exclusion criteria that take the observed variation in such a model into consideration. Objective measures include the identification and exclusion of pre-damaged slices and outliers. Six steps were outlined in this study. Results A six-step approach to enhance comparability is proposed and summarized in a flowchart. We applied the suggested measures to data derived from our TBI-experiments examining the impact of three different interventions in 1459 OHBS. Our exemplary results show that through equal requirements set for all slices more precise findings are ensured. Conclusion Results in a TBI experiment on OHBS should be analyzed critically as inhomogeneities may occur. In order to ensure more precise findings, a structured approach of comparing the results should be followed. Further research is recommended to confirm and further develop this framework.
Collapse
Affiliation(s)
- Linda Grüßer
- Department of Anesthesiology, RWTH Aachen University Hospital, Aachen, Germany
| | | | - Rolf Rossaint
- Department of Anesthesiology, RWTH Aachen University Hospital, Aachen, Germany
| | - Matthias Krings
- Department of Anesthesiology and Intensive Care, Medizinisches Zentrum StaedteRegion Aachen, Aachen, Germany
| | - Benedikt Kremer
- Department of Neurosurgery, RWTH Aachen University Hospital, Aachen, Germany
| | - Anke Höllig
- Department of Neurosurgery, RWTH Aachen University Hospital, Aachen, Germany
| | - Mark Coburn
- Department of Anesthesiology, RWTH Aachen University Hospital, Aachen, Germany
| |
Collapse
|
33
|
Humpel C. Organotypic Brain Slices of ADULT Transgenic Mice: A Tool to Study Alzheimer's Disease. Curr Alzheimer Res 2020; 16:172-181. [PMID: 30543174 DOI: 10.2174/1567205016666181212153138] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 11/23/2018] [Accepted: 11/29/2018] [Indexed: 01/21/2023]
Abstract
Transgenic mice have been extensively used to study the Alzheimer pathology. In order to reduce, refine and replace (3Rs) the number of animals, ex vivo cultures are used and optimized. Organotypic brain slices are the most potent ex vivo slice culture models, keeping the 3-dimensional structure of the brain and being closest to the in vivo situation. Organotypic brain slice cultures have been used for many decades but were mainly prepared from postnatal (day 8-10) old rats or mice. More recent work (including our lab) now aims to culture organotypic brain slices from adult mice including transgenic mice. Especially in Alzheimer´s disease research, brain slices from adult transgenic mice will be useful to study beta-amyloid plaques, tau pathology and glial activation. This review will summarize the studies using organotypic brain slice cultures from adult mice to mimic Alzheimer's disease and will highlight advantages and also pitfalls using this technique.
Collapse
Affiliation(s)
- Christian Humpel
- Laboratory of Psychiatry and Experimental Alzheimer's Research, Medical University of Innsbruck, Innsbruck, Austria
| |
Collapse
|
34
|
Hamad MIK, Daoud S, Petrova P, Rabaya O, Jbara A, Melliti N, Stichmann S, Reiss G, Herz J, Förster E. Biolistic transfection and expression analysis of acute cortical slices. J Neurosci Methods 2020; 337:108666. [PMID: 32119875 DOI: 10.1016/j.jneumeth.2020.108666] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 02/21/2020] [Accepted: 02/27/2020] [Indexed: 12/28/2022]
Abstract
BACKGROUND Biolistic gene gun transfection has been used to transfect organotypic cultures (OTCs) or dissociated cultures in vitro. Here, we modified this technique to allow successful transfection of acute brain slices, followed by measurement of neuronal activity within a few hours. NEW METHOD We established biolistic transfection of murine acute cortical slices to measure calcium signals. Acute slices are mounted on plasma/thrombin coagulate and transfected with a calcium sensor. Imaging can be performed within 4 h post transfection without affecting cell viability. RESULTS Four hours after GCaMP6s transfection, acute slices display remarkable fluorescent protein expression level allowing to study spontaneous activity and receptor pharmacology. While optimal gas pressure (150 psi) and gold particle size used (1 μm) confirm previously published protocols, the amount of 5 μg DNA was found to be optimal for particle coating. COMPARISON WITH EXISTING METHODS The major advantage of this technique is the rapid disposition of acute slices for calcium imaging. No transgenic GECI expressing animals or OTC for long periods are required. In acute slices, network interaction and connectivity are preserved. The method allows to obtain physiological readouts within 4 h, before functional tissue modifications might come into effect. Limitations of this technique are random transfection, low expression efficiency when using specific promotors, and preclusion or genetic manipulations that require a prolonged time before physiological changes become measurable, such as expression of recombinant proteins that require transport to distant subcellular localizations. CONCLUSION The method is optimal for short-time investigation of calcium signals in acute slices.
Collapse
Affiliation(s)
- Mohammad I K Hamad
- Institute for Anatomy and Clinical Morphology, School of Medicine, Faculty of Health, University of Witten/Herdecke, Witten, Germany; Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Medical Faculty, Bochum, Germany.
| | - Solieman Daoud
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Medical Faculty, Bochum, Germany
| | - Petya Petrova
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Medical Faculty, Bochum, Germany
| | - Obada Rabaya
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Medical Faculty, Bochum, Germany
| | - Abdalrahim Jbara
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Medical Faculty, Bochum, Germany
| | - Nesrine Melliti
- Institute for Anatomy and Clinical Morphology, School of Medicine, Faculty of Health, University of Witten/Herdecke, Witten, Germany
| | - Sarah Stichmann
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Medical Faculty, Bochum, Germany
| | - Gebhard Reiss
- Institute for Anatomy and Clinical Morphology, School of Medicine, Faculty of Health, University of Witten/Herdecke, Witten, Germany
| | - Joachim Herz
- Departments of Molecular Genetics, Neuroscience, Neurology and Neurotherapeutics, Center for Translational Neurodegeneration Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Eckart Förster
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Medical Faculty, Bochum, Germany
| |
Collapse
|
35
|
Kreuzer M, García PS, Brucklacher-Waldert V, Claassen R, Schneider G, Antkowiak B, Drexler B. Diazepam and ethanol differently modulate neuronal activity in organotypic cortical cultures. BMC Neurosci 2019; 20:58. [PMID: 31823754 PMCID: PMC6902402 DOI: 10.1186/s12868-019-0540-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 11/24/2019] [Indexed: 12/17/2022] Open
Abstract
Background The pharmacodynamic results of diazepam and ethanol administration are similar, in that each can mediate amnestic and sedative-hypnotic effects. Although each of these molecules effectively reduce the activity of central neurons, diazepam does so through modulation of a more specific set of receptor targets (GABAA receptors containing a γ-subunit), while alcohol is less selective in its receptor bioactivity. Our investigation focuses on divergent actions of diazepam and ethanol on the firing patterns of cultured cortical neurons. Method We used electrophysiological recordings from organotypic slice cultures derived from Sprague–Dawley rat neocortex. We exposed these cultures to either diazepam (15 and 30 µM, n = 7) or ethanol (30 and 60 mM, n = 11) and recorded the electrical activity at baseline and experimental conditions. For analysis, we extracted the episodes of spontaneous activity, i.e., cortical up-states. After separation of action potential and local field potential (LFP) activity, we looked at differences in the number of action potentials, in the spectral power of the LFP, as well as in the coupling between action potential and LFP phase. Results While both substances seem to decrease neocortical action potential firing in a not significantly different (p = 0.659, Mann–Whitney U) fashion, diazepam increases the spectral power of the up-state without significantly impacting the spectral composition, whereas ethanol does not significantly change the spectral power but the oscillatory architecture of the up-state as revealed by the Friedman test with Bonferroni correction (p < 0.05). Further, the action potential to LFP-phase coupling reveals a synchronizing effect of diazepam for a wide frequency range and a narrow-band de-synchronizing effect for ethanol (p < 0.05, Kolmogorov–Smirnov test). Conclusion Diazepam and ethanol, induce specific patterns of network depressant actions. Diazepam induces cortical network inhibition and increased synchronicity via gamma subunit containing GABAA receptors. Ethanol also induces cortical network inhibition, but without an increase in synchronicity via a wider span of molecular targets.
Collapse
Affiliation(s)
- Matthias Kreuzer
- Department of Anesthesiology and Intensive Care, Klinikum rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Paul S García
- Department of Anesthesiology, Neuroanesthesia Division, Columbia University Medical Center, New York Presbyterian Hospital, New York, USA
| | - Verena Brucklacher-Waldert
- Dept. of Anesthesiology and Intensive Care, Experimental Anesthesiology Section, University Hospital Tübingen, Tübingen, Germany.,Horizon Discovery, 8100 Cambridge Research Park, Waterbeach, Cambridge, CB25 9TL, UK
| | - Rebecca Claassen
- Dept. of Anesthesiology and Intensive Care, Experimental Anesthesiology Section, University Hospital Tübingen, Tübingen, Germany.,Psychiatrie-Zentrum Linthgebiet, Standort Rapperswil, Untere Bahnhofstrasse 11, 8640, Rapperswil, Switzerland
| | - Gerhard Schneider
- Department of Anesthesiology and Intensive Care, Klinikum rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Bernd Antkowiak
- Dept. of Anesthesiology and Intensive Care, Experimental Anesthesiology Section, University Hospital Tübingen, Tübingen, Germany.,Werner Reichardt Center for Integrative Neuroscience, Tübingen, Germany
| | - Berthold Drexler
- Dept. of Anesthesiology and Intensive Care, Experimental Anesthesiology Section, University Hospital Tübingen, Tübingen, Germany.
| |
Collapse
|
36
|
Croft CL, Futch HS, Moore BD, Golde TE. Organotypic brain slice cultures to model neurodegenerative proteinopathies. Mol Neurodegener 2019; 14:45. [PMID: 31791377 PMCID: PMC6889333 DOI: 10.1186/s13024-019-0346-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/13/2019] [Indexed: 01/30/2023] Open
Abstract
Organotypic slice cultures of brain or spinal cord have been a longstanding tool in neuroscience research but their utility for understanding Alzheimer's disease (AD) and other neurodegenerative proteinopathies has only recently begun to be evaluated. Organotypic brain slice cultures (BSCs) represent a physiologically relevant three-dimensional model of the brain. BSCs support all the central nervous system (CNS) cell types and can be produced from brain areas involved in neurodegenerative disease. BSCs can be used to better understand the induction and significance of proteinopathies underlying the development and progression of AD and other neurodegenerative disorders, and in the future may serve as bridging technologies between cell culture and in vivo experiments for the development and evaluation of novel therapeutic targets and strategies. We review the initial development and general use of BSCs in neuroscience research and highlight the advantages of these cultures as an ex vivo model. Subsequently we focus on i) BSC-based modeling of AD and other neurodegenerative proteinopathies ii) use of BSCs to understand mechanisms underlying these diseases and iii) how BSCs can serve as tools to screen for suitable therapeutics prior to in vivo investigations. Finally, we will examine i) open questions regarding the use of such cultures and ii) how emerging technologies such as recombinant adeno-associated viruses (rAAV) may be combined with these models to advance translational research relevant to neurodegenerative disorders.
Collapse
Affiliation(s)
- C L Croft
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.,Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - H S Futch
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.,Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - B D Moore
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.,Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - T E Golde
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL, 32610, USA. .,Center for Translational Research in Neurodegenerative Disease, College of Medicine, University of Florida, Gainesville, FL, 32610, USA. .,McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
| |
Collapse
|
37
|
Soldado-Magraner S, Brandalise F, Honnuraiah S, Pfeiffer M, Moulinier M, Gerber U, Douglas R. Conditioning by subthreshold synaptic input changes the intrinsic firing pattern of CA3 hippocampal neurons. J Neurophysiol 2019; 123:90-106. [PMID: 31721636 DOI: 10.1152/jn.00506.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Unlike synaptic strength, intrinsic excitability is assumed to be a stable property of neurons. For example, learning of somatic conductances is generally not incorporated into computational models, and the discharge pattern of neurons in response to test stimuli is frequently used as a basis for phenotypic classification. However, it is increasingly evident that signal processing properties of neurons are more generally plastic on the timescale of minutes. Here we demonstrate that the intrinsic firing patterns of CA3 neurons of the rat hippocampus in vitro undergo rapid long-term plasticity in response to a few minutes of only subthreshold synaptic conditioning. This plasticity on the spike timing could also be induced by intrasomatic injection of subthreshold depolarizing pulses and was blocked by kinase inhibitors, indicating that discharge dynamics are modulated locally. Cluster analysis of firing patterns before and after conditioning revealed systematic transitions toward adapting and intrinsic burst behaviors, irrespective of the patterns initially exhibited by the cells. We used a conductance-based model to decide appropriate pharmacological blockade and found that the observed transitions are likely due to recruitment of low-voltage calcium and Kv7 potassium conductances. We conclude that CA3 neurons adapt their conductance profile to the subthreshold activity of their input, so that their intrinsic firing pattern is not a static signature, but rather a reflection of their history of subthreshold activity. In this way, recurrent output from CA3 neurons may collectively shape the temporal dynamics of their embedding circuits.NEW & NOTEWORTHY Although firing patterns are widely conserved across the animal phyla, it is still a mystery why nerve cells present such diversity of discharge dynamics upon somatic step currents. Adding a new timing dimension to the intrinsic plasticity literature, here we show that CA3 neurons rapidly adapt through the space of known firing patterns in response to the subthreshold signals that they receive from their embedding circuit, potentially adjusting their network processing to the temporal statistics of their circuit.
Collapse
Affiliation(s)
| | - Federico Brandalise
- Brain Research Institute, University of Zurich, Switzerland.,Department of Fundamental Neurosciences, University of Geneva, Switzerland
| | - Suraj Honnuraiah
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, Switzerland
| | - Michael Pfeiffer
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, Switzerland
| | - Marie Moulinier
- Department of Fundamental Neurosciences, University of Geneva, Switzerland
| | - Urs Gerber
- Brain Research Institute, University of Zurich, Switzerland
| | - Rodney Douglas
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, Switzerland
| |
Collapse
|
38
|
Inselman A, Liu F, Wang C, Shi Q, Pang L, Mattes W, White M, Lyn-Cook B, Rosas-Hernandez H, Cuevas E, Lantz S, Imam S, Ali S, Petibone DM, Shemansky JM, Xiong R, Wang Y, Tripathi P, Cao X, Heflich RH, Slikker W. Dr. Daniel Acosta and In Vitro toxicology at the U.S. Food and Drug Administration's National Center for Toxicological Research. Toxicol In Vitro 2019; 64:104471. [PMID: 31628011 DOI: 10.1016/j.tiv.2019.03.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 03/01/2019] [Accepted: 03/04/2019] [Indexed: 10/25/2022]
Abstract
For the past five years, Dr. Daniel Acosta has served as the Deputy Director of Research at the National Center for Toxicological Research (NCTR), a principle research laboratory of the U.S. Food and Drug Administration (FDA). Over his career at NCTR, Dr. Acosta has had a major impact on developing and promoting the use of in vitro assays in regulatory toxicity and product safety assessments. As Dr. Acosta nears his retirement we have dedicated this paper to his many accomplishments at the NCTR. Described within this paper are some of the in vitro studies that have been conducted under Dr. Acosta's leadership. These studies include toxicological assessments involving developmental effects, and the development and application of in vitro reproductive, heart, liver, neurological and airway cell and tissue models.
Collapse
Affiliation(s)
- Amy Inselman
- Division of Systems Biology, NCTR, FDA, Jefferson, AR 72079, USA
| | - Fang Liu
- Division of Neurotoxicology, NCTR, FDA, Jefferson, AR 72079, USA
| | - Cheng Wang
- Division of Neurotoxicology, NCTR, FDA, Jefferson, AR 72079, USA
| | - Qiang Shi
- Division of Systems Biology, NCTR, FDA, Jefferson, AR 72079, USA
| | - Li Pang
- Division of Systems Biology, NCTR, FDA, Jefferson, AR 72079, USA
| | - William Mattes
- Division of Systems Biology, NCTR, FDA, Jefferson, AR 72079, USA
| | - Matthew White
- Arkansas College of Osteopathic Medicine, Fort Smith, AR 72916, USA
| | - Beverly Lyn-Cook
- Division of Biochemical Toxicology, NCTR, FDA, Jefferson, AR 72079, USA
| | | | - Elvis Cuevas
- Division of Neurotoxicology, NCTR, FDA, Jefferson, AR 72079, USA
| | - Susan Lantz
- Division of Neurotoxicology, NCTR, FDA, Jefferson, AR 72079, USA
| | - Syed Imam
- Division of Neurotoxicology, NCTR, FDA, Jefferson, AR 72079, USA
| | - Syed Ali
- Division of Neurotoxicology, NCTR, FDA, Jefferson, AR 72079, USA
| | - Dayton M Petibone
- Division of Genetic and Molecular Toxicology, NCTR, FDA, Jefferson, AR 72079, USA
| | - Jennifer M Shemansky
- Division of Genetic and Molecular Toxicology, NCTR, FDA, Jefferson, AR 72079, USA
| | - Rui Xiong
- Division of Genetic and Molecular Toxicology, NCTR, FDA, Jefferson, AR 72079, USA
| | - Yiying Wang
- Division of Genetic and Molecular Toxicology, NCTR, FDA, Jefferson, AR 72079, USA
| | - Priya Tripathi
- Division of Genetic and Molecular Toxicology, NCTR, FDA, Jefferson, AR 72079, USA
| | - Xuefei Cao
- Division of Genetic and Molecular Toxicology, NCTR, FDA, Jefferson, AR 72079, USA
| | - Robert H Heflich
- Division of Genetic and Molecular Toxicology, NCTR, FDA, Jefferson, AR 72079, USA
| | | |
Collapse
|
39
|
Maysinger D, Ji J. Nanostructured Modulators of Neuroglia. Curr Pharm Des 2019; 25:3905-3916. [PMID: 31512994 DOI: 10.2174/1381612825666190912163339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 06/08/2019] [Indexed: 01/08/2023]
Abstract
Biological and synthetic nanostructures can influence both glia and neurons in the central nervous system. Neurons represent only a small proportion (about 10%) of cells in the brain, whereas glial cells are the most abundant cell type. Non-targeted nanomedicines are mainly internalized by glia, in particular microglia, and to a lesser extent by astrocytes. Internalized nanomedicines by glia indirectly modify the functional status of neurons. The mechanisms of biochemical, morphological and functional changes of neural cells exposed to nanomedicines are still not well-understood. This minireview provides a cross-section of morphological and biochemical changes in glial cells and neurons exposed to different classes of hard and soft nanostructures.
Collapse
Affiliation(s)
- Dusica Maysinger
- Department of Pharmacology and Therapeutics, Faculty of Medicine, McGill University, Montreal, Quebec H3AOG4, Canada
| | - Jeff Ji
- Department of Pharmacology and Therapeutics, Faculty of Medicine, McGill University, Montreal, Quebec H3AOG4, Canada
| |
Collapse
|
40
|
Denizot A, Arizono M, Nägerl UV, Soula H, Berry H. Simulation of calcium signaling in fine astrocytic processes: Effect of spatial properties on spontaneous activity. PLoS Comput Biol 2019; 15:e1006795. [PMID: 31425510 PMCID: PMC6726244 DOI: 10.1371/journal.pcbi.1006795] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 09/04/2019] [Accepted: 07/08/2019] [Indexed: 12/20/2022] Open
Abstract
Astrocytes, a glial cell type of the central nervous system, have emerged as detectors and regulators of neuronal information processing. Astrocyte excitability resides in transient variations of free cytosolic calcium concentration over a range of temporal and spatial scales, from sub-microdomains to waves propagating throughout the cell. Despite extensive experimental approaches, it is not clear how these signals are transmitted to and integrated within an astrocyte. The localization of the main molecular actors and the geometry of the system, including the spatial organization of calcium channels IP3R, are deemed essential. However, as most calcium signals occur in astrocytic ramifications that are too fine to be resolved by conventional light microscopy, most of those spatial data are unknown and computational modeling remains the only methodology to study this issue. Here, we propose an IP3R-mediated calcium signaling model for dynamics in such small sub-cellular volumes. To account for the expected stochasticity and low copy numbers, our model is both spatially explicit and particle-based. Extensive simulations show that spontaneous calcium signals arise in the model via the interplay between excitability and stochasticity. The model reproduces the main forms of calcium signals and indicates that their frequency crucially depends on the spatial organization of the IP3R channels. Importantly, we show that two processes expressing exactly the same calcium channels can display different types of calcium signals depending on the spatial organization of the channels. Our model with realistic process volume and calcium concentrations successfully reproduces spontaneous calcium signals that we measured in calcium micro-domains with confocal microscopy and predicts that local variations of calcium indicators might contribute to the diversity of calcium signals observed in astrocytes. To our knowledge, this model is the first model suited to investigate calcium dynamics in fine astrocytic processes and to propose plausible mechanisms responsible for their variability.
Collapse
Affiliation(s)
- Audrey Denizot
- INRIA, F-69603, Villeurbanne, France
- Univ Lyon, LIRIS, UMR5205 CNRS, F-69621, Villeurbanne, France
| | - Misa Arizono
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - U. Valentin Nägerl
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France
- Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - Hédi Soula
- INRIA, F-69603, Villeurbanne, France
- Univ P&M Curie, CRC, INSERM UMRS 1138, F-75006, Paris, France
| | - Hugues Berry
- INRIA, F-69603, Villeurbanne, France
- Univ Lyon, LIRIS, UMR5205 CNRS, F-69621, Villeurbanne, France
| |
Collapse
|
41
|
Toricelli M, Evangelista SR, Oliveira LR, Viel TA, Buck HS. Neuroprotective Effects of Kinin B2 Receptor in Organotypic Hippocampal Cultures of Middle-Aged Mice. Front Aging Neurosci 2019; 11:168. [PMID: 31354470 PMCID: PMC6639675 DOI: 10.3389/fnagi.2019.00168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 06/17/2019] [Indexed: 11/13/2022] Open
Abstract
Aging is a multifactorial phenomenon that results in several changes at cellular and molecular levels and is considered the main risk factor for some neurodegenerative diseases. Several evidence show the participation of the kallikrein-kinin system (KKS) in neurodegeneration and this system has been associated with inflammation and immunogenic responses in the central and peripheral systems by the activation of the B1 and B2 receptors. Previous work by our group showed that bradykinin (BK) and the B2 receptor played a possible role in neuroprotection. Therefore, the objective of this study was to evaluate the participation of B2 receptors in cell viability, neuroinflammatory response and neuroplasticity in organotypic hippocampal cultures (OHCs) of 6- and 12-month-old mice. It was observed that activation of the B2 receptor by bradykinin decreased the inflammatory response and increased plasticity in 12-month-old slices. Conversely, there was an increase in the inflammatory response and a decrease in neural plasticity in the 6-month-old slices. In both ages, an increase in cell viability was observed. This data suggests that the function of the kinin B2 receptor in the hippocampus is modulated by age, providing neuroprotective action in old age.
Collapse
Affiliation(s)
- Mariana Toricelli
- Department of Physiological Sciences, Santa Casa de São Paulo School of Medical Sciences, São Paulo, Brazil.,Research Group on Neuropharmacology of Aging-ReGNA, São Paulo, Brazil
| | - Sebastiana Ribeiro Evangelista
- Department of Physiological Sciences, Santa Casa de São Paulo School of Medical Sciences, São Paulo, Brazil.,Research Group on Neuropharmacology of Aging-ReGNA, São Paulo, Brazil
| | - Larissa Rolim Oliveira
- Department of Physiological Sciences, Santa Casa de São Paulo School of Medical Sciences, São Paulo, Brazil
| | - Tania Araujo Viel
- Research Group on Neuropharmacology of Aging-ReGNA, São Paulo, Brazil.,School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, Brazil
| | - Hudson Sousa Buck
- Department of Physiological Sciences, Santa Casa de São Paulo School of Medical Sciences, São Paulo, Brazil.,Research Group on Neuropharmacology of Aging-ReGNA, São Paulo, Brazil
| |
Collapse
|
42
|
Glasgow SD, McPhedrain R, Madranges JF, Kennedy TE, Ruthazer ES. Approaches and Limitations in the Investigation of Synaptic Transmission and Plasticity. Front Synaptic Neurosci 2019; 11:20. [PMID: 31396073 PMCID: PMC6667546 DOI: 10.3389/fnsyn.2019.00020] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 07/04/2019] [Indexed: 12/16/2022] Open
Abstract
The numbers and strengths of synapses in the brain change throughout development, and even into adulthood, as synaptic inputs are added, eliminated, and refined in response to ongoing neural activity. A number of experimental techniques can assess these changes, including single-cell electrophysiological recording which offers measurements of synaptic inputs with high temporal resolution. Coupled with electrical stimulation, photoactivatable opsins, and caged compounds, to facilitate fine spatiotemporal control over release of neurotransmitters, electrophysiological recordings allow for precise dissection of presynaptic and postsynaptic mechanisms of action. Here, we discuss the strengths and pitfalls of various techniques commonly used to analyze synapses, including miniature excitatory/inhibitory (E/I) postsynaptic currents, evoked release, and optogenetic stimulation. Together, these techniques can provide multiple lines of convergent evidence to generate meaningful insight into the emergence of circuit connectivity and maturation. A full understanding of potential caveats and alternative explanations for findings is essential to avoid data misinterpretation.
Collapse
Affiliation(s)
| | | | | | | | - Edward S. Ruthazer
- Department of Neurology & Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal, QC, Canada
| |
Collapse
|
43
|
Li S, Li Y, Li H, Yang C, Lin J. Use of in vitro electroporation and slice culture for gene function analysis in the mouse embryonic spinal cord. Mech Dev 2019; 158:103558. [PMID: 31212004 DOI: 10.1016/j.mod.2019.103558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/04/2019] [Accepted: 06/14/2019] [Indexed: 10/26/2022]
Abstract
The spinal cord is an important part of the central nervous system (CNS). At present, the expression of the exogenous gene in the spinal cord of the embryonic mouse needs in utero spinal cord electroporation, but the success rate of this technique is very low. In this study, we have demonstrated the expression of an exogenous gene on one side of the spinal cord by combining two methods-in vitro electroporation of embryonic mouse spinal cord and organ spinal cord slices culture. We took 12-day embryonic mice, injected the green fluorescent protein (pCAGGS-GFP) plasmid into the spinal cord cavity in vitro, and then electroporated. The spinal cord was cut into 300-μm slices using a vibratory microtome. After cultured for 48 h, GFP-positive neurons were clearly observed on one side of the spinal cord, indicating that the exogenous gene was successfully transferred. The axon projection direction is basically unanimous from the inside to the lateral edge of the spinal cord. Compared to neurons in vivo, a single neuron in the culturing section has more complete neurites and is conducive to studying changes in the structure and behavior of individual neurons. Based on the above results, we have successfully established a convenient and efficient method for expressing the exogenous gene in the spinal cord of the mouse.
Collapse
Affiliation(s)
- Shuanqing Li
- College of Life Science and Technology, Xinxiang Medical University, Xinxiang 453003, China
| | - Yunxiao Li
- College of Life Science and Technology, Xinxiang Medical University, Xinxiang 453003, China
| | - Han Li
- College of Life Science and Technology, Xinxiang Medical University, Xinxiang 453003, China
| | - Ciqing Yang
- College of Life Science and Technology, Xinxiang Medical University, Xinxiang 453003, China; Henan Key Laboratory of Medical Tissue Regeneration, Xinxiang Medical University, Xinxiang 453003, China.
| | - Juntang Lin
- Henan Key Laboratory of Medical Tissue Regeneration, Xinxiang Medical University, Xinxiang 453003, China; College of Biomedical Engineering, Xinxiang Medical University, Xinxiang 453003, China.
| |
Collapse
|
44
|
Linsley JW, Tripathi A, Epstein I, Schmunk G, Mount E, Campioni M, Oza V, Barch M, Javaherian A, Nowakowski TJ, Samsi S, Finkbeiner S. Automated four-dimensional long term imaging enables single cell tracking within organotypic brain slices to study neurodevelopment and degeneration. Commun Biol 2019; 2:155. [PMID: 31069265 PMCID: PMC6494885 DOI: 10.1038/s42003-019-0411-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 03/18/2019] [Indexed: 02/08/2023] Open
Abstract
Current approaches for dynamic profiling of single cells rely on dissociated cultures, which lack important biological features existing in tissues. Organotypic slice cultures preserve aspects of structural and synaptic organisation within the brain and are amenable to microscopy, but established techniques are not well adapted for high throughput or longitudinal single cell analysis. Here we developed a custom-built, automated confocal imaging platform, with improved organotypic slice culture and maintenance. The approach enables fully automated image acquisition and four-dimensional tracking of morphological changes within individual cells in organotypic cultures from rodent and human primary tissues for at least 3 weeks. To validate this system, we analysed neurons expressing a disease-associated version of huntingtin (HTT586Q138-EGFP), and observed that they displayed hallmarks of Huntington's disease and died sooner than controls. By facilitating longitudinal single-cell analyses of neuronal physiology, our system bridges scales necessary to attain statistical power to detect developmental and disease phenotypes.
Collapse
Affiliation(s)
- Jeremy W Linsley
- Gladstone Center for Systems and Therapeutics, San Francisco, CA 94158 USA
| | - Atmiyata Tripathi
- Gladstone Center for Systems and Therapeutics, San Francisco, CA 94158 USA
| | - Irina Epstein
- Gladstone Center for Systems and Therapeutics, San Francisco, CA 94158 USA
| | - Galina Schmunk
- 2Department of Anatomy, University of California, San Francisco, CA 94158 USA
| | - Elliot Mount
- Gladstone Center for Systems and Therapeutics, San Francisco, CA 94158 USA
| | - Matthew Campioni
- Gladstone Center for Systems and Therapeutics, San Francisco, CA 94158 USA
| | - Viral Oza
- Gladstone Center for Systems and Therapeutics, San Francisco, CA 94158 USA
| | - Mariya Barch
- Gladstone Center for Systems and Therapeutics, San Francisco, CA 94158 USA
| | - Ashkan Javaherian
- Gladstone Center for Systems and Therapeutics, San Francisco, CA 94158 USA
| | - Tomasz J Nowakowski
- 2Department of Anatomy, University of California, San Francisco, CA 94158 USA
| | - Siddharth Samsi
- 3Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Luxembourg, L-4367 Luxembourg
- 9Present Address: MIT Lincoln Laboratory, Lexington, MA 02421 USA
| | - Steven Finkbeiner
- Gladstone Center for Systems and Therapeutics, San Francisco, CA 94158 USA
- 4Neuroscience Graduate Program, University of California, San Francisco, CA 94158 USA
- 5Biomedical Sciences and Neuroscience Graduate Program, University of California, San Francisco, CA 94143 USA
- 6Taube/Koret Center for Neurodegenerative Disease, Gladstone Institutes, San Francisco, CA 94158 USA
- 7Department of Neurology, University of California, San Francisco, CA 94158 USA
- 8Department of Physiology, University of California, San Francisco, CA 94158 USA
| |
Collapse
|
45
|
Viswam V, Obien MEJ, Franke F, Frey U, Hierlemann A. Optimal Electrode Size for Multi-Scale Extracellular-Potential Recording From Neuronal Assemblies. Front Neurosci 2019; 13:385. [PMID: 31105515 PMCID: PMC6498989 DOI: 10.3389/fnins.2019.00385] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 04/03/2019] [Indexed: 01/24/2023] Open
Abstract
Advances in microfabrication technology have enabled the production of devices containing arrays of thousands of closely spaced recording electrodes, which afford subcellular resolution of electrical signals in neurons and neuronal networks. Rationalizing the electrode size and configuration in such arrays demands consideration of application-specific requirements and inherent features of the electrodes. Tradeoffs among size, spatial density, sensitivity, noise, attenuation, and other factors are inevitable. Although recording extracellular signals from neurons with planar metal electrodes is fairly well established, the effects of the electrode characteristics on the quality and utility of recorded signals, especially for small, densely packed electrodes, have yet to be fully characterized. Here, we present a combined experimental and computational approach to elucidating how electrode size, and size-dependent parameters, such as impedance, baseline noise, and transmission characteristics, influence recorded neuronal signals. Using arrays containing platinum electrodes of different sizes, we experimentally evaluated the electrode performance in the recording of local field potentials (LFPs) and extracellular action potentials (EAPs) from the following cell preparations: acute brain slices, dissociated cell cultures, and organotypic slice cultures. Moreover, we simulated the potential spatial decay of point-current sources to investigate signal averaging using known signal sources. We demonstrated that the noise and signal attenuation depend more on the electrode impedance than on electrode size, per se, especially for electrodes <10 μm in width or diameter to achieve high-spatial-resolution readout. By minimizing electrode impedance of small electrodes (<10 μm) via surface modification, we could maximize the signal-to-noise ratio to electrically visualize the propagation of axonal EAPs and to isolate single-unit spikes. Due to the large amplitude of LFP signals, recording quality was high and nearly independent of electrode size. These findings should be of value in configuring in vitro and in vivo microelectrode arrays for extracellular recordings with high spatial resolution in various applications.
Collapse
Affiliation(s)
- Vijay Viswam
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
- MaxWell Biosystems AG, Basel, Switzerland
| | - Marie Engelene J. Obien
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
- MaxWell Biosystems AG, Basel, Switzerland
| | - Felix Franke
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
| | - Urs Frey
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
- MaxWell Biosystems AG, Basel, Switzerland
| | - Andreas Hierlemann
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
| |
Collapse
|
46
|
Romero-Leguizamón CR, Elnagar MR, Kristiansen U, Kohlmeier KA. Increasing cellular lifespan with a flow system in organotypic culture of the Laterodorsal Tegmentum (LDT). Sci Rep 2019; 9:1486. [PMID: 30728375 PMCID: PMC6365664 DOI: 10.1038/s41598-018-37606-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 12/10/2018] [Indexed: 12/31/2022] Open
Abstract
Organotypic brain culture is an experimental tool widely used in neuroscience studies. One major drawback of this technique is reduced neuronal survival across time, which is likely exacerbated by the loss of blood flow. We have designed a novel, tube flow system, which is easily incorporated into the commonly-used, standard semi-permeable membrane culture methodology which has significantly enhanced neuronal survival in a brain stem nucleus involved in control of motivated and arousal states: the laterodorsal tegmental nucleus (LDT). Our automated system provides nutrients and removes waste in a comparatively aseptic environment, while preserving temperature, and oxygen levels. Using immunohistochemistry and electrophysiology, our system was found superior to standard techniques in preserving tissue quality and survival of LDT cells for up to 2 weeks. In summary, we provide evidence for the first time that the LDT can be preserved in organotypic slice culture, and further, our technical improvements of adding a flow system, which likely enhanced perfusion to the slice, were associated with enhanced neuronal survival. Our perfusion system is expected to facilitate organotypic experiments focused on chronic stimulations and multielectrode recordings in the LDT, as well as enhance neuronal survival in slice cultures originating from other brain regions.
Collapse
Affiliation(s)
- César R Romero-Leguizamón
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Mohamed R Elnagar
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt
| | - Uffe Kristiansen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Kristi A Kohlmeier
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2100, Denmark.
| |
Collapse
|
47
|
Pandamooz S, Salehi MS, Zibaii MI, Safari A, Nabiuni M, Ahmadiani A, Dargahi L. Modeling traumatic injury in organotypic spinal cord slice culture obtained from adult rat. Tissue Cell 2019; 56:90-97. [DOI: 10.1016/j.tice.2019.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/04/2018] [Accepted: 01/08/2019] [Indexed: 12/16/2022]
|
48
|
Ji J, Moquin A, Bertorelle F, KY Chang P, Antoine R, Luo J, McKinney RA, Maysinger D. Organotypic and primary neural cultures as models to assess effects of different gold nanostructures on glia and neurons. Nanotoxicology 2019; 13:285-304. [DOI: 10.1080/17435390.2018.1543468] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Jeff Ji
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Canada
| | - Alexandre Moquin
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Canada
| | - Franck Bertorelle
- CNRS, Institut Lumière Matière, Université Lyon Université Claude Bernard Lyon 1, Lyon, France
| | - Philip KY Chang
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Canada
| | - Rodolphe Antoine
- CNRS, Institut Lumière Matière, Université Lyon Université Claude Bernard Lyon 1, Lyon, France
| | - Julia Luo
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Canada
| | - R. Anne McKinney
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Canada
| | - Dusica Maysinger
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Canada
| |
Collapse
|
49
|
Jacob T, Lillis KP, Wang Z, Swiercz W, Rahmati N, Staley KJ. A Proposed Mechanism for Spontaneous Transitions between Interictal and Ictal Activity. J Neurosci 2019; 39:557-575. [PMID: 30446533 PMCID: PMC6335741 DOI: 10.1523/jneurosci.0719-17.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 10/23/2018] [Accepted: 10/31/2018] [Indexed: 11/21/2022] Open
Abstract
Epileptic networks are characterized by two outputs: brief interictal spikes and rarer, more prolonged seizures. Although either output state is readily modeled in silico and induced experimentally, the transition mechanisms are unknown, in part because no models exhibit both output states spontaneously. In silico small-world neural networks were built using single-compartment neurons whose physiological parameters were derived from dual whole-cell recordings of pyramidal cells in organotypic hippocampal slice cultures that were generating spontaneous seizure-like activity. In silico, neurons were connected by abundant local synapses and rare long-distance synapses. Activity-dependent synaptic depression and gradual recovery delimited synchronous activity. Full synaptic recovery engendered interictal population spikes that spread via long-distance synapses. When synaptic recovery was incomplete, postsynaptic neurons required coincident activation of multiple presynaptic terminals to reach firing threshold. Only local connections were sufficiently dense to spread activity under these conditions. This coalesced network activity into traveling waves whose velocity varied with synaptic recovery. Seizures were comprised of sustained traveling waves that were similar to those recorded during experimental and human neocortical seizures. Sustained traveling waves occurred only when wave velocity, network dimensions, and the rate of synaptic recovery enabled wave reentry into previously depressed areas at precisely ictogenic levels of synaptic recovery. Wide-field, cellular-resolution GCamP7b calcium imaging demonstrated similar initial patterns of activation in the hippocampus, although the anatomical distribution of traveling waves of synaptic activation was altered by the pattern of synaptic connectivity in the organotypic hippocampal cultures.SIGNIFICANCE STATEMENT When computerized distributed neural network models are required to generate both features of epileptic networks (i.e., spontaneous interictal population spikes and seizures), the network structure is substantially constrained. These constraints provide important new hypotheses regarding the nature of epileptic networks and mechanisms of seizure onset.
Collapse
Affiliation(s)
- Theju Jacob
- Massachusetts General Hospital, Boston, Massachusetts 02114
- Harvard Medical School, Boston, MA 02115
| | - Kyle P Lillis
- Massachusetts General Hospital, Boston, Massachusetts 02114
- Harvard Medical School, Boston, MA 02115
| | - Zemin Wang
- Brigham and Women's Hospital, Boston, MA 02115, and
- Harvard Medical School, Boston, MA 02115
| | - Waldemar Swiercz
- Massachusetts General Hospital, Boston, Massachusetts 02114
- Harvard Medical School, Boston, MA 02115
| | - Negah Rahmati
- Massachusetts General Hospital, Boston, Massachusetts 02114
- Harvard Medical School, Boston, MA 02115
| | - Kevin J Staley
- Massachusetts General Hospital, Boston, Massachusetts 02114,
- Harvard Medical School, Boston, MA 02115
| |
Collapse
|
50
|
Neumann E, Rudolph U, Knutson DE, Li G, Cook JM, Hentschke H, Antkowiak B, Drexler B. Zolpidem Activation of Alpha 1-Containing GABA A Receptors Selectively Inhibits High Frequency Action Potential Firing of Cortical Neurons. Front Pharmacol 2019; 9:1523. [PMID: 30687091 PMCID: PMC6333667 DOI: 10.3389/fphar.2018.01523] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 12/12/2018] [Indexed: 11/13/2022] Open
Abstract
Introduction: High frequency neuronal activity in the cerebral cortex can be induced by noxious stimulation during surgery, brain injury or poisoning. In this scenario, it is essential to block cortical hyperactivity to protect the brain against damage, e.g., by using drugs that act as positive allosteric modulators at GABAA receptors. Yet, cortical neurons express multiple, functionally distinct GABAA receptor subtypes. Currently there is a lack of knowledge which GABAA receptor subtypes would be a good pharmacological target to reduce extensive cortical activity. Methods: Spontaneous action potential activity was monitored by performing extracellular recordings from organotypic neocortical slice cultures of wild type and GABAAR-α1(H101R) mutant mice. Phases of high neuronal activity were characterized using peri-event time histograms. Drug effects on within-up state firing rates were quantified via Hedges' g. Results: We quantified the effects of zolpidem, a positive modulator of GABAA receptors harboring α1-subunits, and the experimental benzodiazepine SH-053-2'F-S-CH3, which preferably acts at α2/3/5- but spares α1-subunits. Both agents decreased spontaneous action potential activity but altered the firing patterns in different ways. Zolpidem reduced action potential firing during highly active network states. This action was abolished by flumazenil, suggesting that it was mediated by benzodiazepine-sensitive GABAA receptors. SH-053-2'F-S-CH3 also attenuated neuronal activity, but unlike zolpidem, failed to reduce high frequency firing. To confirm that zolpidem actions were indeed mediated via α1-dependent actions, it was evaluated in slices from wild type and α(H101R) knock-in mice. Inhibition of high frequency action potential firing was observed in slices from wild type but not mutant mice. Conclusion: Our results suggest that during episodes of scarce and high neuronal activity action potential firing of cortical neurons is controlled by different GABAA receptor subtypes. Exaggerated firing of cortical neurons is reduced by positive modulation of α1-, but not α2/3/5-subunit containing GABAA receptors.
Collapse
Affiliation(s)
- Elena Neumann
- Experimental Anesthesiology Section, Department of Anesthesiology and Intensive Care, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Uwe Rudolph
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Daniel E Knutson
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Guanguan Li
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - James M Cook
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Harald Hentschke
- Experimental Anesthesiology Section, Department of Anesthesiology and Intensive Care, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Bernd Antkowiak
- Experimental Anesthesiology Section, Department of Anesthesiology and Intensive Care, Eberhard Karls Universität Tübingen, Tübingen, Germany.,Werner Reichardt Center for Integrative Neuroscience, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Berthold Drexler
- Experimental Anesthesiology Section, Department of Anesthesiology and Intensive Care, Eberhard Karls Universität Tübingen, Tübingen, Germany
| |
Collapse
|