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Striebel J, Kalinski L, Sturm M, Drouvé N, Peters S, Lichterfeld Y, Habibey R, Hauslage J, El Sheikh S, Busskamp V, Liemersdorf C. Human neural network activity reacts to gravity changes in vitro. Front Neurosci 2023; 17:1085282. [PMID: 36968488 PMCID: PMC10030604 DOI: 10.3389/fnins.2023.1085282] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 02/06/2023] [Indexed: 03/11/2023] Open
Abstract
During spaceflight, humans experience a variety of physiological changes due to deviations from familiar earth conditions. Specifically, the lack of gravity is responsible for many effects observed in returning astronauts. These impairments can include structural as well as functional changes of the brain and a decline in cognitive performance. However, the underlying physiological mechanisms remain elusive. Alterations in neuronal activity play a central role in mental disorders and altered neuronal transmission may also lead to diminished human performance in space. Thus, understanding the influence of altered gravity at the cellular and network level is of high importance. Previous electrophysiological experiments using patch clamp techniques and calcium indicators have shown that neuronal activity is influenced by altered gravity. By using multi-electrode array (MEA) technology, we advanced the electrophysiological investigation covering single-cell to network level responses during exposure to decreased (micro-) or increased (hyper-) gravity conditions. We continuously recorded in real-time the spontaneous activity of human induced pluripotent stem cell (hiPSC)-derived neural networks in vitro. The MEA device was integrated into a custom-built environmental chamber to expose the system with neuronal cultures to up to 6 g of hypergravity on the Short-Arm Human Centrifuge at the DLR Cologne, Germany. The flexibility of the experimental hardware set-up facilitated additional MEA electrophysiology experiments under 4.7 s of high-quality microgravity (10–6 to 10–5 g) in the Bremen drop tower, Germany. Hypergravity led to significant changes in activity. During the microgravity phase, the mean action potential frequency across the neural networks was significantly enhanced, whereas different subgroups of neurons showed distinct behaviors, such as increased or decreased firing activity. Our data clearly demonstrate that gravity as an environmental stimulus triggers changes in neuronal activity. Neuronal networks especially reacted to acute changes in mechanical loading (hypergravity) or de-loading (microgravity). The current study clearly shows the gravity-dependent response of neuronal networks endorsing the importance of further investigations of neuronal activity and its adaptive responses to micro- and hypergravity. Our approach provided the basis for the identification of responsible mechanisms and the development of countermeasures with potential implications on manned space missions.
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Affiliation(s)
- Johannes Striebel
- Department of Ophthalmology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Laura Kalinski
- Department of Gravitational Biology, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | - Maximilian Sturm
- Department of Gravitational Biology, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | - Nils Drouvé
- Department of Applied Sciences, Cologne University of Applied Sciences, Leverkusen, Germany
| | - Stefan Peters
- Department of Applied Sciences, Cologne University of Applied Sciences, Leverkusen, Germany
| | - Yannick Lichterfeld
- Department of Gravitational Biology, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | - Rouhollah Habibey
- Department of Ophthalmology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Jens Hauslage
- Department of Gravitational Biology, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | - Sherif El Sheikh
- Department of Applied Sciences, Cologne University of Applied Sciences, Leverkusen, Germany
| | - Volker Busskamp
- Department of Ophthalmology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Christian Liemersdorf
- Department of Gravitational Biology, Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
- *Correspondence: Christian Liemersdorf,
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Habibey R. Incubator-independent perfusion system integrated with microfluidic device for continuous electrophysiology and microscopy readouts. Biofabrication 2023; 15. [PMID: 36652708 DOI: 10.1088/1758-5090/acb466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 01/18/2023] [Indexed: 01/20/2023]
Abstract
Advances in primary and stem cell derived neuronal cell culture techniques and abundance of available neuronal cell types have enabledin vitroneuroscience as a substantial approach to modelin vivoneuronal networks. Survival of the cultured neurons is inevitably dependent on the cell culture incubators to provide stable temperature and humidity and to supply required CO2levels for controlling the pH of culture medium. Therefore, imaging and electrophysiology recordings outside of the incubator are often limited to the short-term experimental sessions. This restricts our understanding of physiological events to the short snapshots of recorded data while the major part of temporal data is neglected. Multiple custom-made and commercially available platforms like integrated on-stage incubators have been designed to enable long-term microscopy. Nevertheless, long-term high-spatiotemporal electrophysiology recordings from developing neuronal networks needs to be addressed. In the present work an incubator-independent polydimethylsiloxane-based double-wall perfusion chamber was designed and integrated with multi-electrode arrays (MEAs) electrophysiology and compartmentalized microfluidic device to continuously record from engineered neuronal networks at sub-cellular resolution. Cell culture media underwent iterations of conditioning to the ambient CO2and adjusting its pH to physiological ranges to retain a stable pH for weeks outside of the incubator. Double-wall perfusion chamber and an integrated air bubble trapper reduced media evaporation and osmolality drifts of the conditioned media for two weeks. Aligned microchannel-microfluidic device on MEA electrodes allowed neurite growth on top of the planar electrodes and amplified their extracellular activity. This enabled continuous sub-cellular resolution imaging and electrophysiology recordings from developing networks and their growing neurites. The on-chip versatile and self-contained system provides long-term, continuous and high spatiotemporal access to the network data and offers a robustin vitroplatform with many potentials to be applied on advanced cell culture systems including organ-on-chip and organoid models.
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Affiliation(s)
- Rouhollah Habibey
- Department of Ophthalmology, Universitäts-Augenklinik Bonn, University of Bonn, Ernst-Abbe-Straße 2, D-53127 Bonn, Germany.,CRTD-Center for Regenerative Therapies TU Dresden, 01307 Dresden, Germany
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Habibey R, Striebel J, Schmieder F, Czarske J, Busskamp V. Long-term morphological and functional dynamics of human stem cell-derived neuronal networks on high-density micro-electrode arrays. Front Neurosci 2022; 16:951964. [PMID: 36267241 PMCID: PMC9578684 DOI: 10.3389/fnins.2022.951964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 09/06/2022] [Indexed: 11/13/2022] Open
Abstract
Comprehensive electrophysiological characterizations of human induced pluripotent stem cell (hiPSC)-derived neuronal networks are essential to determine to what extent these in vitro models recapitulate the functional features of in vivo neuronal circuits. High-density micro-electrode arrays (HD-MEAs) offer non-invasive recording with the best spatial and temporal resolution possible to date. For 3 months, we tracked the morphology and activity features of developing networks derived from a transgenic hiPSC line in which neurogenesis is inducible by neurogenic transcription factor overexpression. Our morphological data revealed large-scale structural changes from homogeneously distributed neurons in the first month to the formation of neuronal clusters over time. This led to a constant shift in position of neuronal cells and clusters on HD-MEAs and corresponding changes in spatial distribution of the network activity maps. Network activity appeared as scarce action potentials (APs), evolved as local bursts with longer duration and changed to network-wide synchronized bursts with higher frequencies but shorter duration over time, resembling the emerging burst features found in the developing human brain. Instantaneous firing rate data indicated that the fraction of fast spiking neurons (150–600 Hz) increases sharply after 63 days post induction (dpi). Inhibition of glutamatergic synapses erased burst features from network activity profiles and confirmed the presence of mature excitatory neurotransmission. The application of GABAergic receptor antagonists profoundly changed the bursting profile of the network at 120 dpi. This indicated a GABAergic switch from excitatory to inhibitory neurotransmission during circuit development and maturation. Our results suggested that an emerging GABAergic system at older culture ages is involved in regulating spontaneous network bursts. In conclusion, our data showed that long-term and continuous microscopy and electrophysiology readouts are crucial for a meaningful characterization of morphological and functional maturation in stem cell-derived human networks. Most importantly, assessing the level and duration of functional maturation is key to subject these human neuronal circuits on HD-MEAs for basic and biomedical applications.
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Affiliation(s)
- Rouhollah Habibey
- Department of Ophthalmology, Universitäts-Augenklinik Bonn, University of Bonn, Bonn, Germany
| | - Johannes Striebel
- Department of Ophthalmology, Universitäts-Augenklinik Bonn, University of Bonn, Bonn, Germany
| | - Felix Schmieder
- Laboratory of Measurement and Sensor System Technique, Faculty of Electrical and Computer Engineering, TU Dresden, Dresden, Germany
| | - Jürgen Czarske
- Laboratory of Measurement and Sensor System Technique, Faculty of Electrical and Computer Engineering, TU Dresden, Dresden, Germany
- Competence Center for Biomedical Computational Laser Systems (BIOLAS), TU Dresden, Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, Germany
- School of Science, Institute of Applied Physics, TU Dresden, Dresden, Germany
| | - Volker Busskamp
- Department of Ophthalmology, Universitäts-Augenklinik Bonn, University of Bonn, Bonn, Germany
- *Correspondence: Volker Busskamp,
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Habibey R, Rojo Arias JE, Striebel J, Busskamp V. Microfluidics for Neuronal Cell and Circuit Engineering. Chem Rev 2022; 122:14842-14880. [PMID: 36070858 PMCID: PMC9523714 DOI: 10.1021/acs.chemrev.2c00212] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Indexed: 02/07/2023]
Abstract
The widespread adoption of microfluidic devices among the neuroscience and neurobiology communities has enabled addressing a broad range of questions at the molecular, cellular, circuit, and system levels. Here, we review biomedical engineering approaches that harness the power of microfluidics for bottom-up generation of neuronal cell types and for the assembly and analysis of neural circuits. Microfluidics-based approaches are instrumental to generate the knowledge necessary for the derivation of diverse neuronal cell types from human pluripotent stem cells, as they enable the isolation and subsequent examination of individual neurons of interest. Moreover, microfluidic devices allow to engineer neural circuits with specific orientations and directionality by providing control over neuronal cell polarity and permitting the isolation of axons in individual microchannels. Similarly, the use of microfluidic chips enables the construction not only of 2D but also of 3D brain, retinal, and peripheral nervous system model circuits. Such brain-on-a-chip and organoid-on-a-chip technologies are promising platforms for studying these organs as they closely recapitulate some aspects of in vivo biological processes. Microfluidic 3D neuronal models, together with 2D in vitro systems, are widely used in many applications ranging from drug development and toxicology studies to neurological disease modeling and personalized medicine. Altogether, microfluidics provide researchers with powerful systems that complement and partially replace animal models.
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Affiliation(s)
- Rouhollah Habibey
- Department
of Ophthalmology, Universitäts-Augenklinik
Bonn, University of Bonn, Ernst-Abbe-Straße 2, D-53127 Bonn, Germany
| | - Jesús Eduardo Rojo Arias
- Wellcome—MRC
Cambridge Stem Cell Institute, Jeffrey Cheah Biomedical Centre, Cambridge
Biomedical Campus, University of Cambridge, Cambridge CB2 0AW, United Kingdom
| | - Johannes Striebel
- Department
of Ophthalmology, Universitäts-Augenklinik
Bonn, University of Bonn, Ernst-Abbe-Straße 2, D-53127 Bonn, Germany
| | - Volker Busskamp
- Department
of Ophthalmology, Universitäts-Augenklinik
Bonn, University of Bonn, Ernst-Abbe-Straße 2, D-53127 Bonn, Germany
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