1
|
Patel D, Shetty S, Acha C, Pantoja IEM, Zhao A, George D, Gracias DH. Microinstrumentation for Brain Organoids. Adv Healthc Mater 2024; 13:e2302456. [PMID: 38217546 DOI: 10.1002/adhm.202302456] [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: 07/30/2023] [Revised: 12/10/2023] [Indexed: 01/15/2024]
Abstract
Brain organoids are three-dimensional aggregates of self-organized differentiated stem cells that mimic the structure and function of human brain regions. Organoids bridge the gaps between conventional drug screening models such as planar mammalian cell culture, animal studies, and clinical trials. They can revolutionize the fields of developmental biology, neuroscience, toxicology, and computer engineering. Conventional microinstrumentation for conventional cellular engineering, such as planar microfluidic chips; microelectrode arrays (MEAs); and optical, magnetic, and acoustic techniques, has limitations when applied to three-dimensional (3D) organoids, primarily due to their limits with inherently two-dimensional geometry and interfacing. Hence, there is an urgent need to develop new instrumentation compatible with live cell culture techniques and with scalable 3D formats relevant to organoids. This review discusses conventional planar approaches and emerging 3D microinstrumentation necessary for advanced organoid-machine interfaces. Specifically, this article surveys recently developed microinstrumentation, including 3D printed and curved microfluidics, 3D and fast-scan optical techniques, buckling and self-folding MEAs, 3D interfaces for electrochemical measurements, and 3D spatially controllable magnetic and acoustic technologies relevant to two-way information transfer with brain organoids. This article highlights key challenges that must be addressed for robust organoid culture and reliable 3D spatiotemporal information transfer.
Collapse
Affiliation(s)
- Devan Patel
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Saniya Shetty
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Chris Acha
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Itzy E Morales Pantoja
- Center for Alternatives to Animal Testing (CAAT), Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Alice Zhao
- Department of Biology, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Derosh George
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - David H Gracias
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Laboratory for Computational Sensing and Robotics (LCSR), Johns Hopkins University, Baltimore, MD, 21218, USA
- Sidney Kimmel Comprehensive Cancer Center (SKCCC), Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
- Center for MicroPhysiological Systems (MPS), Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| |
Collapse
|
2
|
Smirnova L, Hartung T. The Promise and Potential of Brain Organoids. Adv Healthc Mater 2024; 13:e2302745. [PMID: 38252094 DOI: 10.1002/adhm.202302745] [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: 08/20/2023] [Revised: 12/22/2023] [Indexed: 01/23/2024]
Abstract
Brain organoids are 3D in vitro culture systems derived from human pluripotent stem cells that self-organize to model features of the (developing) human brain. This review examines the techniques behind organoid generation, their current and potential applications, and future directions for the field. Brain organoids possess complex architecture containing various neural cell types, synapses, and myelination. They have been utilized for toxicology testing, disease modeling, infection studies, personalized medicine, and gene-environment interaction studies. An emerging concept termed Organoid Intelligence (OI) combines organoids with artificial intelligence systems to generate learning and memory, with the goals of modeling cognition and enabling biological computing applications. Brain organoids allow neuroscience studies not previously achievable with traditional techniques, and have the potential to transform disease modeling, drug development, and the understanding of human brain development and disorders. The aspirational vision of OI parallels the origins of artificial intelligence, and efforts are underway to map a roadmap toward its realization. In summary, brain organoids constitute a disruptive technology that is rapidly advancing and gaining traction across multiple disciplines.
Collapse
Affiliation(s)
- Lena Smirnova
- Center for Alternatives to Animal Testing (CAAT), Bloomberg School of Public Health and Whiting School of Engineering, Johns Hopkins University, 615 N Wolfe St, Baltimore, MD, 21205, USA
| | - Thomas Hartung
- Center for Alternatives to Animal Testing (CAAT), Bloomberg School of Public Health and Whiting School of Engineering, Johns Hopkins University, 615 N Wolfe St, Baltimore, MD, 21205, USA
- CAAT-Europe, University of Konstanz, Universitätsstr. 10, 78464, Konstanz, BW, Germany
| |
Collapse
|
3
|
Faltus T, Freise J, Fluck C, Zillmann H. Ethics and regulation of neuronal optogenetics in the European Union. Pflugers Arch 2023; 475:1505-1517. [PMID: 37996706 PMCID: PMC10730653 DOI: 10.1007/s00424-023-02888-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/15/2023] [Accepted: 11/17/2023] [Indexed: 11/25/2023]
Abstract
Neuronal optogenetics is a technique to control the activity of neurons with light. This is achieved by artificial expression of light-sensitive ion channels in the target cells. By optogenetic methods, cells that are naturally light-insensitive can be made photosensitive and addressable by illumination and precisely controllable in time and space. So far, optogenetics has primarily been a basic research tool to better understand the brain. However, initial studies are already investigating the possibility of using optogenetics in humans for future therapeutic approaches for neuronal based diseases such as Parkinson's disease, epilepsy, or to promote stroke recovery. In addition, optogenetic methods have already been successfully applied to a human in an experimental setting. Neuronal optogenetics also raises ethical and legal issues, e.g., in relation to, animal experiments, and its application in humans. Additional ethical and legal questions may arise when optogenetic methods are investigated on cerebral organoids. Thus, for the successful translation of optogenetics from basic research to medical practice, the ethical and legal questions of this technology must also be answered, because open ethical and legal questions can hamper the translation. The paper provides an overview of the ethical and legal issues raised by neuronal optogenetics. In addition, considering the technical prerequisites for translation, the paper shows consistent approaches to address these open questions. The paper also aims to support the interdisciplinary dialogue between scientists and physicians on the one hand, and ethicists and lawyers on the other, to enable an interdisciplinary coordinated realization of neuronal optogenetics.
Collapse
Affiliation(s)
- Timo Faltus
- Law School, Faculty of Law, Economics and Business, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Johannes Freise
- Law School, Faculty of Law, Economics and Business, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Carsten Fluck
- Law School, Faculty of Law, Economics and Business, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Hans Zillmann
- Law School, Faculty of Law, Economics and Business, Martin Luther University Halle-Wittenberg, Halle, Germany.
| |
Collapse
|
4
|
Dennison R, Usuga E, Chen H, Paul JZ, Arbelaez CA, Teng YD. Direct Cell Reprogramming and Phenotypic Conversion: An Analysis of Experimental Attempts to Transform Astrocytes into Neurons in Adult Animals. Cells 2023; 12:618. [PMID: 36831283 PMCID: PMC9954435 DOI: 10.3390/cells12040618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
Central nervous system (CNS) repair after injury or disease remains an unresolved problem in neurobiology research and an unmet medical need. Directly reprogramming or converting astrocytes to neurons (AtN) in adult animals has been investigated as a potential strategy to facilitate brain and spinal cord recovery and advance fundamental biology. Conceptually, AtN strategies rely on forced expression or repression of lineage-specific transcription factors to make endogenous astrocytes become "induced neurons" (iNs), presumably without re-entering any pluripotent or multipotent states. The AtN-derived cells have been reported to manifest certain neuronal functions in vivo. However, this approach has raised many new questions and alternative explanations regarding the biological features of the end products (e.g., iNs versus neuron-like cells, neural functional changes, etc.), developmental biology underpinnings, and neurobiological essentials. For this paper per se, we proposed to draw an unconventional distinction between direct cell conversion and direct cell reprogramming, relative to somatic nuclear transfer, based on the experimental methods utilized to initiate the transformation process, aiming to promote a more in-depth mechanistic exploration. Moreover, we have summarized the current tactics employed for AtN induction, comparisons between the bench endeavors concerning outcome tangibility, and discussion of the issues of published AtN protocols. Lastly, the urgency to clearly define/devise the theoretical frameworks, cell biological bases, and bench specifics to experimentally validate primary data of AtN studies was highlighted.
Collapse
Affiliation(s)
- Rachel Dennison
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA 02129, USA
- Laboratory of SCI, Stem Cell and Recovery Neurobiology Research, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital Network, Mass General Brigham, and Harvard Medical School, Boston, MA 02115, USA
| | - Esteban Usuga
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA 02129, USA
- Laboratory of SCI, Stem Cell and Recovery Neurobiology Research, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital Network, Mass General Brigham, and Harvard Medical School, Boston, MA 02115, USA
| | - Harriet Chen
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA 02129, USA
- Laboratory of SCI, Stem Cell and Recovery Neurobiology Research, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital Network, Mass General Brigham, and Harvard Medical School, Boston, MA 02115, USA
| | - Jacob Z. Paul
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA 02129, USA
- Laboratory of SCI, Stem Cell and Recovery Neurobiology Research, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital Network, Mass General Brigham, and Harvard Medical School, Boston, MA 02115, USA
| | - Christian A. Arbelaez
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA 02129, USA
- Laboratory of SCI, Stem Cell and Recovery Neurobiology Research, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital Network, Mass General Brigham, and Harvard Medical School, Boston, MA 02115, USA
| | - Yang D. Teng
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, MA 02129, USA
- Laboratory of SCI, Stem Cell and Recovery Neurobiology Research, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital Network, Mass General Brigham, and Harvard Medical School, Boston, MA 02115, USA
- Neurotrauma Recovery Research, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital Network, Mass General Brigham, and Harvard Medical School, Boston, MA 02115, USA
| |
Collapse
|
5
|
Islam J, KC E, So KH, Kim S, Kim HK, Park YY, Park YS. Modulation of trigeminal neuropathic pain by optogenetic inhibition of posterior hypothalamus in CCI-ION rat. Sci Rep 2023; 13:489. [PMID: 36627362 PMCID: PMC9831989 DOI: 10.1038/s41598-023-27610-7] [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: 11/04/2022] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
Posterior hypothalamus (PH), an important part of the descending pain processing pathway, has been found to be activated in trigeminal autonomic cephalalgias. However, there are very few studies conducted and information regarding its implications in trigeminal neuropathic pain (TNP). Therefore, we aimed to ascertain whether optogenetic inhibition of PH could affect the outcomes of a chronic constriction injury in the infraorbital nerve (CCI-ION) rat model. Animals were divided into the TNP animal, sham, and naive-control groups. CCI-ION surgery was performed to mimic TNP symptoms, and the optogenetic or null virus was injected into the ipsilateral PH. In vivo single-unit extracellular recordings were obtained from both the ipsilateral ventrolateral periaqueductal gray (vlPAG) and contralateral ventral posteromedial (VPM) thalamus in stimulation "OFF" and "ON" conditions. Alterations in behavioral responses during the stimulation-OFF and stimulation-ON states were examined. We observed that optogenetic inhibition of the PH considerably improved behavioral responses in TNP animals. We found increased and decreased firing activity in the vlPAG and VPM thalamus, respectively, during optogenetic inhibition of the PH. Inhibiting PH attenuates trigeminal pain signal transmission by modulating the vlPAG and trigeminal nucleus caudalis, thereby providing evidence of the therapeutic potential of PH in TNP management.
Collapse
Affiliation(s)
- Jaisan Islam
- grid.254229.a0000 0000 9611 0917Department of Medical Neuroscience, College of Medicine, Chungbuk National University, Cheongju, Republic of Korea
| | - Elina KC
- grid.254229.a0000 0000 9611 0917Department of Medical Neuroscience, College of Medicine, Chungbuk National University, Cheongju, Republic of Korea
| | - Kyoung Ha So
- grid.254229.a0000 0000 9611 0917Institute for Stem Cell and Regenerative Medicine (ISCRM), College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea ,grid.31501.360000 0004 0470 5905Bio-Max/N-Bio Institute, Institute of Bio-Engineering, Seoul National University, Seoul, Republic of Korea
| | - Soochong Kim
- grid.254229.a0000 0000 9611 0917Department of Veterinary Medicine, College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea
| | - Hyong Kyu Kim
- grid.254229.a0000 0000 9611 0917Department of Medicine and Microbiology, College of Medicine, Chungbuk National University, Cheongju, Republic of Korea
| | - Yoon Young Park
- grid.411725.40000 0004 1794 4809Department of Neurosurgery, Chungbuk National University Hospital, Cheongju, Republic of Korea
| | - Young Seok Park
- Department of Medical Neuroscience, College of Medicine, Chungbuk National University, Cheongju, Republic of Korea. .,Institute for Stem Cell and Regenerative Medicine (ISCRM), College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea. .,Department of Neurosurgery, Chungbuk National University Hospital, Cheongju, Republic of Korea. .,Department of Neurosurgery, Chungbuk National University Hospital, College of Medicine, Chungbuk National University, 776, 1 Sunhwanro, Seowon-gu, Cheongju-Si, Chungbuk, 28644, Republic of Korea.
| |
Collapse
|
6
|
Karagyaur M, Primak A, Efimenko A, Skryabina M, Tkachuk V. The Power of Gene Technologies: 1001 Ways to Create a Cell Model. Cells 2022; 11:cells11203235. [PMID: 36291103 PMCID: PMC9599997 DOI: 10.3390/cells11203235] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/01/2022] [Accepted: 10/12/2022] [Indexed: 12/04/2022] Open
Abstract
Modern society faces many biomedical challenges that require urgent solutions. Two of the most important include the elucidation of mechanisms of socially significant diseases and the development of prospective drug treatments for these diseases. Experimental cell models are a convenient tool for addressing many of these problems. The power of cell models is further enhanced when combined with gene technologies, which allows the examination of even more subtle changes within the structure of the genome and permits testing of proteins in a native environment. The list and possibilities of these recently emerging technologies are truly colossal, which requires a rethink of a number of approaches for obtaining experimental cell models. In this review, we analyze the possibilities and limitations of promising gene technologies for obtaining cell models, and also give recommendations on the development and creation of relevant models. In our opinion, this review will be useful for novice cell biologists, as it provides some reference points in the rapidly growing universe of gene and cell technologies.
Collapse
Affiliation(s)
- Maxim Karagyaur
- Institute for Regenerative Medicine, Medical Research and Education Center, Lomonosov Moscow State University, 27/10, Lomonosovsky Ave., 119192 Moscow, Russia
- Faculty of Medicine, Lomonosov Moscow State University, 27/1, Lomonosovsky Ave., 119192 Moscow, Russia
- Correspondence:
| | - Alexandra Primak
- Faculty of Medicine, Lomonosov Moscow State University, 27/1, Lomonosovsky Ave., 119192 Moscow, Russia
| | - Anastasia Efimenko
- Institute for Regenerative Medicine, Medical Research and Education Center, Lomonosov Moscow State University, 27/10, Lomonosovsky Ave., 119192 Moscow, Russia
- Faculty of Medicine, Lomonosov Moscow State University, 27/1, Lomonosovsky Ave., 119192 Moscow, Russia
| | - Mariya Skryabina
- Faculty of Medicine, Lomonosov Moscow State University, 27/1, Lomonosovsky Ave., 119192 Moscow, Russia
| | - Vsevolod Tkachuk
- Institute for Regenerative Medicine, Medical Research and Education Center, Lomonosov Moscow State University, 27/10, Lomonosovsky Ave., 119192 Moscow, Russia
- Faculty of Medicine, Lomonosov Moscow State University, 27/1, Lomonosovsky Ave., 119192 Moscow, Russia
| |
Collapse
|
7
|
Chakraborty S, Parayil R, Mishra S, Nongthomba U, Clement JP. Epilepsy Characteristics in Neurodevelopmental Disorders: Research from Patient Cohorts and Animal Models Focusing on Autism Spectrum Disorder. Int J Mol Sci 2022; 23:ijms231810807. [PMID: 36142719 PMCID: PMC9501968 DOI: 10.3390/ijms231810807] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/31/2022] [Accepted: 09/05/2022] [Indexed: 11/24/2022] Open
Abstract
Epilepsy, a heterogeneous group of brain-related diseases, has continued to significantly burden society and families. Epilepsy comorbid with neurodevelopmental disorders (NDDs) is believed to occur due to multifaceted pathophysiological mechanisms involving disruptions in the excitation and inhibition (E/I) balance impeding widespread functional neuronal circuitry. Although the field has received much attention from the scientific community recently, the research has not yet translated into actionable therapeutics to completely cure epilepsy, particularly those comorbid with NDDs. In this review, we sought to elucidate the basic causes underlying epilepsy as well as those contributing to the association of epilepsy with NDDs. Comprehensive emphasis is put on some key neurodevelopmental genes implicated in epilepsy, such as MeCP2, SYNGAP1, FMR1, SHANK1-3 and TSC1, along with a few others, and the main electrophysiological and behavioral deficits are highlighted. For these genes, the progress made in developing appropriate and valid rodent models to accelerate basic research is also detailed. Further, we discuss the recent development in the therapeutic management of epilepsy and provide a briefing on the challenges and caveats in identifying and testing species-specific epilepsy models.
Collapse
Affiliation(s)
- Sukanya Chakraborty
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
| | - Rrejusha Parayil
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
| | - Shefali Mishra
- Molecular Reproduction, Development and Genetics (MRDG), Indian Institute of Science, Bengaluru 560012, India
| | - Upendra Nongthomba
- Molecular Reproduction, Development and Genetics (MRDG), Indian Institute of Science, Bengaluru 560012, India
| | - James P. Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560064, India
- Correspondence: ; Tel.: +91-08-2208-2613
| |
Collapse
|
8
|
Iyer NR, Ashton RS. Bioengineering the human spinal cord. Front Cell Dev Biol 2022; 10:942742. [PMID: 36092702 PMCID: PMC9458954 DOI: 10.3389/fcell.2022.942742] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 08/01/2022] [Indexed: 12/04/2022] Open
Abstract
Three dimensional, self-assembled organoids that recapitulate key developmental and organizational events during embryogenesis have proven transformative for the study of human central nervous system (CNS) development, evolution, and disease pathology. Brain organoids have predominated the field, but human pluripotent stem cell (hPSC)-derived models of the spinal cord are on the rise. This has required piecing together the complex interactions between rostrocaudal patterning, which specifies axial diversity, and dorsoventral patterning, which establishes locomotor and somatosensory phenotypes. Here, we review how recent insights into neurodevelopmental biology have driven advancements in spinal organoid research, generating experimental models that have the potential to deepen our understanding of neural circuit development, central pattern generation (CPG), and neurodegenerative disease along the body axis. In addition, we discuss the application of bioengineering strategies to drive spinal tissue morphogenesis in vitro, current limitations, and future perspectives on these emerging model systems.
Collapse
Affiliation(s)
- Nisha R. Iyer
- Department of Biomedical Engineering, Tufts University, Medford, MA, United States
- Wisconsin Institute for Discovery, University of Wisconsin—Madison, Madison, WI, United States
- Department of Biomedical Engineering, University of Wisconsin—Madison, Madison, WI, United States
| | - Randolph S. Ashton
- Wisconsin Institute for Discovery, University of Wisconsin—Madison, Madison, WI, United States
- Department of Biomedical Engineering, University of Wisconsin—Madison, Madison, WI, United States
| |
Collapse
|
9
|
Jang H, Kim SH, Koh Y, Yoon KJ. Engineering Brain Organoids: Toward Mature Neural Circuitry with an Intact Cytoarchitecture. Int J Stem Cells 2022; 15:41-59. [PMID: 35220291 PMCID: PMC8889333 DOI: 10.15283/ijsc22004] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 01/19/2022] [Indexed: 11/23/2022] Open
Abstract
The emergence of brain organoids as a model system has been a tremendously exciting development in the field of neuroscience. Brain organoids are a gateway to exploring the intricacies of human-specific neurogenesis that have so far eluded the neuroscience community. Regardless, current culture methods have a long way to go in terms of accuracy and reproducibility. To perfectly mimic the human brain, we need to recapitulate the complex in vivo context of the human fetal brain and achieve mature neural circuitry with an intact cytoarchitecture. In this review, we explore the major challenges facing the current brain organoid systems, potential technical breakthroughs to advance brain organoid techniques up to levels similar to an in vivo human developing brain, and the future prospects of this technology.
Collapse
Affiliation(s)
- Hyunsoo Jang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Seo Hyun Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Youmin Koh
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Ki-Jun Yoon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
- KAIST-Wonjin Cell Therapy Center, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| |
Collapse
|
10
|
Synthetic developmental biology: Engineering approaches to guide multicellular organization. Stem Cell Reports 2022; 17:715-733. [PMID: 35276092 PMCID: PMC9023767 DOI: 10.1016/j.stemcr.2022.02.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 02/05/2022] [Accepted: 02/07/2022] [Indexed: 11/30/2022] Open
Abstract
Multicellular organisms of various complexities self-organize in nature. Organoids are in vitro 3D structures that display important aspects of the anatomy and physiology of their in vivo counterparts and that develop from pluripotent or tissue-specific stem cells through a self-organization process. In this review, we describe the multidisciplinary concept of “synthetic developmental biology” where engineering approaches are employed to guide multicellular organization in an experimental setting. We introduce a novel classification of engineering approaches based on the extent of microenvironmental manipulation applied to organoids. In the final section, we discuss how engineering tools might help overcome current limitations in organoid construction.
Collapse
|
11
|
Veenvliet JV, Lenne PF, Turner DA, Nachman I, Trivedi V. Sculpting with stem cells: how models of embryo development take shape. Development 2021; 148:dev192914. [PMID: 34908102 PMCID: PMC8722391 DOI: 10.1242/dev.192914] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
During embryogenesis, organisms acquire their shape given boundary conditions that impose geometrical, mechanical and biochemical constraints. A detailed integrative understanding how these morphogenetic information modules pattern and shape the mammalian embryo is still lacking, mostly owing to the inaccessibility of the embryo in vivo for direct observation and manipulation. These impediments are circumvented by the developmental engineering of embryo-like structures (stembryos) from pluripotent stem cells that are easy to access, track, manipulate and scale. Here, we explain how unlocking distinct levels of embryo-like architecture through controlled modulations of the cellular environment enables the identification of minimal sets of mechanical and biochemical inputs necessary to pattern and shape the mammalian embryo. We detail how this can be complemented with precise measurements and manipulations of tissue biochemistry, mechanics and geometry across spatial and temporal scales to provide insights into the mechanochemical feedback loops governing embryo morphogenesis. Finally, we discuss how, even in the absence of active manipulations, stembryos display intrinsic phenotypic variability that can be leveraged to define the constraints that ensure reproducible morphogenesis in vivo.
Collapse
Affiliation(s)
- Jesse V. Veenvliet
- Stembryogenesis Lab, Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
- Department of Developmental Genetics, Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany
- Cluster of Excellence Physics of Life, Technische Universität Dresden, 01307 Dresden, Germany
| | - Pierre-François Lenne
- Aix Marseille University, CNRS, IBDM, Turing Center for Living Systems, 13288, Marseille, France
| | - David A. Turner
- Institute of Life Course and Medical Sciences, William Henry Duncan Building, University of Liverpool, Liverpool, L7 8TX, UK
| | - Iftach Nachman
- School of Neurobiology, Biochemistry and Biophysics, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Vikas Trivedi
- European Molecular Biology Laboratories (EMBL), Barcelona, 08003, Spain
- EMBL Heidelberg, Developmental Biology Unit, 69117, Heidelberg, Germany
| |
Collapse
|
12
|
Lavazza A. 'Consciousnessoids': clues and insights from human cerebral organoids for the study of consciousness. Neurosci Conscious 2021; 7:niab029. [PMID: 34729213 PMCID: PMC8557395 DOI: 10.1093/nc/niab029] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 08/02/2021] [Accepted: 08/17/2021] [Indexed: 12/21/2022] Open
Abstract
Human cerebral organoids (HCOs) are an in vitro three-dimensional model of early neural development, aimed at modelling and understanding brain development and neurological disorders. In just a few years, there has been a rapid and considerable progress in the attempt to create a brain model capable of showcasing the structure and functions of the human brain. There are still strong limitations to address, including the absence of vascularization that makes it difficult to feed the central layers of organoids. Nevertheless, some important features of the nervous system have recently been observed: HCOs manifest electrical activity, are sensitive to light stimulation and are able to connect to a spinal cord by sending impulses that make a muscle contract. Recent data show that cortical organoid network development at 10 months resembles some preterm babies' electroencephalography (EEG) patterns. In the light of the fast pace of research in this field, one might consider the hypothesis that HCOs might become a living laboratory for studying the emergence of consciousness and investigating its mechanisms and neural correlates. HCOs could be also a benchmark for different neuroscientific theories of consciousness. In this paper, I propose some potential lines of research and offer some clues and insights so as to use HCOs in trying to unveil some puzzles concerning our conscious states. Finally, I consider some relevant ethical issues regarding this specific experimentation on HCOs and conclude that some of them could require strict regulation in this field.
Collapse
Affiliation(s)
- Andrea Lavazza
- Centro Universitario Internazionale, Via Garbasso, 42, Arezzo 52100, Italy
- University of Pavia, Department of Brain and Behavioural Sciences, Piazza Botta, 11, Pavia 27100, Italy
| |
Collapse
|
13
|
What can biofabrication do for space and what can space do for biofabrication? Trends Biotechnol 2021; 40:398-411. [PMID: 34544616 DOI: 10.1016/j.tibtech.2021.08.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 08/19/2021] [Accepted: 08/23/2021] [Indexed: 01/08/2023]
Abstract
Biofabrication in space is one of the novel promising and prospective research directions in the rapidly emerging field of space STEM. There are several advantages of biofabrication in space. Under microgravity, it is possible to engineer constructs using more fluidic channels and thus more biocompatible bioinks. Microgravity enables biofabrication of tissue and organ constructs of more complex geometries, thus facilitating novel scaffold-, label-, and nozzle-free technologies based on multi-levitation principles. However, when exposed to microgravity and cosmic radiation, biofabricated tissues could be used to study pathophysiological phenomena that will be useful on Earth and for deep space manned missions. Here, we provide leading concepts about the potential mutual benefits of the application of biofabrication technologies in space.
Collapse
|
14
|
Abstract
Long-term effective use of antiretroviral therapy (ART) among people with HIV (PWH) has significantly reduced the burden of disease, yet a cure for HIV has not been universally achieved, likely due to the persistence of an HIV reservoir. The central nervous system (CNS) is an understudied HIV sanctuary. Importantly, due to viral persistence in the brain, cognitive disturbances persist to various degrees at high rates in PWH despite suppressive ART. Given the complexity and accessibility of the CNS compartment and that it is a physiologically and anatomically unique immune site, human studies to reveal molecular mechanisms of viral entry, reservoir establishment, and the cellular and structural interactions leading to viral persistence and brain injury to advance a cure and either prevent or limit cognitive impairments in PWH remain challenging. Recent advances in human brain organoids show that they can mimic the intercellular dynamics of the human brain and may recapitulate many of the events involved in HIV infection of the brain (neuroHIV). Human brain organoids can be produced, spontaneously or with addition of growth factors and at immature or mature states, and have become stronger models to study neurovirulent viral infections of the CNS. While organoids provide opportunities to study neuroHIV, obstacles such as the need to incorporate microglia need to be overcome to fully utilize this model. Here, we review the current achievements in brain organoid biology and their relevance to neuroHIV research efforts.
Collapse
|
15
|
Gritti N, Oriola D, Trivedi V. Rethinking embryology in vitro: A synergy between engineering, data science and theory. Dev Biol 2021; 474:48-61. [DOI: 10.1016/j.ydbio.2020.10.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/21/2020] [Accepted: 10/26/2020] [Indexed: 02/06/2023]
|
16
|
Hoffmann A, Spengler D. Single-Cell Transcriptomics Supports a Role of CHD8 in Autism. Int J Mol Sci 2021; 22:3261. [PMID: 33806835 PMCID: PMC8004931 DOI: 10.3390/ijms22063261] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/16/2021] [Accepted: 03/20/2021] [Indexed: 12/16/2022] Open
Abstract
Chromodomain helicase domain 8 (CHD8) is one of the most frequently mutated and most penetrant genes in the autism spectrum disorder (ASD). Individuals with CHD8 mutations show leading symptoms of autism, macrocephaly, and facial dysmorphisms. The molecular and cellular mechanisms underpinning the early onset and development of these symptoms are still poorly understood and prevent timely and more efficient therapies of patients. Progress in this area will require an understanding of "when, why and how cells deviate from their normal trajectories". High-throughput single-cell RNA sequencing (sc-RNAseq) directly quantifies information-bearing RNA molecules that enact each cell's biological identity. Here, we discuss recent insights from sc-RNAseq of CRISPR/Cas9-editing of Chd8/CHD8 during mouse neocorticogenesis and human cerebral organoids. Given that the deregulation of the balance between excitation and inhibition (E/I balance) in cortical and subcortical circuits is thought to represent a major etiopathogenetic mechanism in ASD, we focus on the question of whether, and to what degree, results from current sc-RNAseq studies support this hypothesis. Beyond that, we discuss the pros and cons of these approaches and further steps to be taken to harvest the full potential of these transformative techniques.
Collapse
Affiliation(s)
| | - Dietmar Spengler
- Translational Research in Psychiatry, Max Planck Institute of Psychiatry, 80804 Munich, Germany;
| |
Collapse
|
17
|
Forro C, Caron D, Angotzi GN, Gallo V, Berdondini L, Santoro F, Palazzolo G, Panuccio G. Electrophysiology Read-Out Tools for Brain-on-Chip Biotechnology. MICROMACHINES 2021; 12:124. [PMID: 33498905 PMCID: PMC7912435 DOI: 10.3390/mi12020124] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 02/07/2023]
Abstract
Brain-on-Chip (BoC) biotechnology is emerging as a promising tool for biomedical and pharmaceutical research applied to the neurosciences. At the convergence between lab-on-chip and cell biology, BoC couples in vitro three-dimensional brain-like systems to an engineered microfluidics platform designed to provide an in vivo-like extrinsic microenvironment with the aim of replicating tissue- or organ-level physiological functions. BoC therefore offers the advantage of an in vitro reproduction of brain structures that is more faithful to the native correlate than what is obtained with conventional cell culture techniques. As brain function ultimately results in the generation of electrical signals, electrophysiology techniques are paramount for studying brain activity in health and disease. However, as BoC is still in its infancy, the availability of combined BoC-electrophysiology platforms is still limited. Here, we summarize the available biological substrates for BoC, starting with a historical perspective. We then describe the available tools enabling BoC electrophysiology studies, detailing their fabrication process and technical features, along with their advantages and limitations. We discuss the current and future applications of BoC electrophysiology, also expanding to complementary approaches. We conclude with an evaluation of the potential translational applications and prospective technology developments.
Collapse
Affiliation(s)
- Csaba Forro
- Tissue Electronics, Fondazione Istituto Italiano di Tecnologia, Largo Barsanti e Matteucci, 53-80125 Naples, Italy; (C.F.); (F.S.)
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Davide Caron
- Enhanced Regenerative Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (D.C.); (V.G.)
| | - Gian Nicola Angotzi
- Microtechnology for Neuroelectronics, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (G.N.A.); (L.B.)
| | - Vincenzo Gallo
- Enhanced Regenerative Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (D.C.); (V.G.)
| | - Luca Berdondini
- Microtechnology for Neuroelectronics, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (G.N.A.); (L.B.)
| | - Francesca Santoro
- Tissue Electronics, Fondazione Istituto Italiano di Tecnologia, Largo Barsanti e Matteucci, 53-80125 Naples, Italy; (C.F.); (F.S.)
| | - Gemma Palazzolo
- Enhanced Regenerative Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (D.C.); (V.G.)
| | - Gabriella Panuccio
- Enhanced Regenerative Medicine, Fondazione Istituto Italiano di Tecnologia, Via Morego, 30-16163 Genova, Italy; (D.C.); (V.G.)
| |
Collapse
|
18
|
Passaro AP, Stice SL. Electrophysiological Analysis of Brain Organoids: Current Approaches and Advancements. Front Neurosci 2021; 14:622137. [PMID: 33510616 PMCID: PMC7835643 DOI: 10.3389/fnins.2020.622137] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 12/11/2020] [Indexed: 12/23/2022] Open
Abstract
Brain organoids, or cerebral organoids, have become widely used to study the human brain in vitro. As pluripotent stem cell-derived structures capable of self-organization and recapitulation of physiological cell types and architecture, brain organoids bridge the gap between relatively simple two-dimensional human cell cultures and non-human animal models. This allows for high complexity and physiological relevance in a controlled in vitro setting, opening the door for a variety of applications including development and disease modeling and high-throughput screening. While technologies such as single cell sequencing have led to significant advances in brain organoid characterization and understanding, improved functional analysis (especially electrophysiology) is needed to realize the full potential of brain organoids. In this review, we highlight key technologies for brain organoid development and characterization, then discuss current electrophysiological methods for brain organoid analysis. While electrophysiological approaches have improved rapidly for two-dimensional cultures, only in the past several years have advances been made to overcome limitations posed by the three-dimensionality of brain organoids. Here, we review major advances in electrophysiological technologies and analytical methods with a focus on advances with applicability for brain organoid analysis.
Collapse
Affiliation(s)
- Austin P. Passaro
- Regenerative Bioscience Center, University of Georgia, Athens, GA, United States
- Division of Neuroscience, Biomedical & Health Sciences Institute, University of Georgia, Athens, GA, United States
| | - Steven L. Stice
- Regenerative Bioscience Center, University of Georgia, Athens, GA, United States
- Division of Neuroscience, Biomedical & Health Sciences Institute, University of Georgia, Athens, GA, United States
- Department of Animal and Dairy Science, University of Georgia, Athens, GA, United States
| |
Collapse
|
19
|
Somuncu ÖS, Berns HM, Sanchez JG. New Pioneers of Optogenetics in Neuroscience. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1288:47-60. [PMID: 31983055 DOI: 10.1007/5584_2019_473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Optogenetics have recently increased in popularity as tools to study behavior in response to the brain and how these trends relate back to a neuronal circuit. Additionally, the high demand for human cerebral tissue in research has led to the generation of a new model to investigate human brain development and disease. Human Pluripotent Stem Cells (hPSCs) have been previously used to recapitulate the development of several tissues such as intestine, stomach and liver and to model disease in a human context, recently new improvements have been made in the field of hPSC-derived brain organoids to better understand overall brain development but more specifically, to mimic inter-neuronal communication. This review aims to highlight the recent advances in these two separate approaches of brain research and to emphasize the need for overlap. These two novel approaches would combine the study of behavior along with the specific circuits required to produce the signals causing such behavior. This review is focused on the current state of the field, as well as the development of novel optogenetic technologies and their potential for current scientific study and potential therapeutic use.
Collapse
Affiliation(s)
- Ö Sezin Somuncu
- Department of Medical Biology, Bahçeşehir University Faculty of Medicine, İstanbul, Turkey.
| | - H Matthew Berns
- Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, USA
| | - J Guillermo Sanchez
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| |
Collapse
|
20
|
Alikhani M, Karamzadeh R, Rahimi P, Adib S, Baharvand H, Salekdeh GH. Human Proteome Project and Human Pluripotent Stem Cells: Odd Bedfellows or a Perfect Match? J Proteome Res 2020; 19:4747-4753. [PMID: 33124832 DOI: 10.1021/acs.jproteome.0c00689] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The Chromosome-Centric Human Proteome Project (C-HPP) aims at the identification of missing proteins (MPs) and the functional characterization of functionally unannotated PE1 (uPE1) proteins. A major challenge in addressing this goal is that many human proteins and MPs are silent in adult cells. A promising approach to overcome such challenge is to exploit the advantage of novel tools such as pluripotent stem cells (PSCs), which are capable of differentiation into three embryonic germ layers, namely, the endoderm, mesoderm, and ectoderm. Here we present several examples of how the Human Y Chromosome Proteome Project (Y-HPP) benefited from this approach to meet C-HPP goals. Furthermore, we discuss how integrating CRISPR engineering, human-induced pluripotent stem cell (hiPSC)-derived disease modeling systems, and organoid technologies provides a unique platform for Y-HPP and C-HPP for MP identification and the functional characterization of human proteins, especially uPE1s.
Collapse
Affiliation(s)
- Mehdi Alikhani
- Department of Molecular Systems Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran 16635-148, Iran
| | - Razieh Karamzadeh
- Department of Molecular Systems Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran 16635-148, Iran
| | - Pardis Rahimi
- Department of Molecular Systems Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran 16635-148, Iran
| | - Samane Adib
- Department of Anatomy, Faculty of Medical Sciences, Tarbiat Modares University, Tehran 14115-111, Iran
| | - Hossein Baharvand
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran 16635-148, Iran.,Department of Developmental Biology, University of Science and Culture, Tehran 146196815, Iran
| | - Ghasem Hosseini Salekdeh
- Department of Molecular Systems Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran 16635-148, Iran.,Department of Molecular Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| |
Collapse
|
21
|
Chiaradia I, Lancaster MA. Brain organoids for the study of human neurobiology at the interface of in vitro and in vivo. Nat Neurosci 2020; 23:1496-1508. [PMID: 33139941 DOI: 10.1038/s41593-020-00730-3] [Citation(s) in RCA: 156] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 09/29/2020] [Indexed: 02/07/2023]
Abstract
Brain development is an extraordinarily complex process achieved through the spatially and temporally regulated release of key patterning factors. In vitro neurodevelopmental models seek to mimic these processes to recapitulate the steps of tissue fate acquisition and morphogenesis. Classic two-dimensional neural cultures present higher homogeneity but lower complexity compared to the brain. Brain organoids instead have more advanced cell composition, maturation and tissue architecture. They can thus be considered at the interface of in vitro and in vivo neurobiology, and further improvements in organoid techniques are continuing to narrow the gap with in vivo brain development. Here we describe these efforts to recapitulate brain development in neural organoids and focus on their applicability for disease modeling, evolutionary studies and neural network research.
Collapse
Affiliation(s)
- Ilaria Chiaradia
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK
| | - Madeline A Lancaster
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, UK.
| |
Collapse
|
22
|
Shen Y, Campbell RE, Côté DC, Paquet ME. Challenges for Therapeutic Applications of Opsin-Based Optogenetic Tools in Humans. Front Neural Circuits 2020; 14:41. [PMID: 32760252 PMCID: PMC7373823 DOI: 10.3389/fncir.2020.00041] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/16/2020] [Indexed: 12/29/2022] Open
Abstract
As the technological hurdles are overcome and optogenetic techniques advance to have more control over neurons, therapies based on these approaches will begin to emerge in the clinic. Here, we consider the technical challenges surrounding the transition of this breakthrough technology from an investigative tool to a true therapeutic avenue. The emerging strategies and remaining tasks surrounding genetically encoded molecules which respond to light as well as the vehicles required to deliver them are discussed.The use of optogenetics in humans would represent a completely new paradigm in medicine and would be associated with unprecedented technical considerations. To be applied for stimulation of neurons in humans, an ideal optogenetic tool would need to be non-immunogenic, highly sensitive, and activatable with red light or near-infrared light (to maximize light penetration while minimizing photodamage). To enable sophisticated levels of neuronal control, the combined use of optogenetic actuators and indicators could enable closed-loop all-optical neuromodulation. Such systems would introduce additional challenges related to spectral orthogonality between actuator and indicator, the need for decision making computational algorithms and requirements for large gene cassettes. As in any gene therapy, the therapeutic efficiency of optogenetics will rely on vector delivery and expression in the appropriate cell type. Although viral vectors such as those based on AAVs are showing great potential in human trials, barriers to their general use remain, including immune responses, delivery/transport, and liver clearance. Limitations associated with the gene cassette size which can be packaged in currently approved vectors also need to be addressed.
Collapse
Affiliation(s)
- Yi Shen
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Robert E Campbell
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada.,Department of Chemistry, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Daniel C Côté
- Centre de Recherche CERVO, Université Laval, Quebec City, QC, Canada.,Département de Physique et Génie Physique, Université Laval, Quebec City, QC, Canada
| | - Marie-Eve Paquet
- Centre de Recherche CERVO, Université Laval, Quebec City, QC, Canada.,Département de Biochimie, Microbiologie et Bioinformatique, Université Laval, Quebec City, QC, Canada
| |
Collapse
|