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Rathbun DL, Jalligampala A, Zrenner E, Hosseinzadeh Z. Improvements for recording retinal function with Microelectrode Arrays. MethodsX 2024; 12:102543. [PMID: 38313698 PMCID: PMC10834997 DOI: 10.1016/j.mex.2023.102543] [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: 12/02/2023] [Accepted: 12/28/2023] [Indexed: 02/06/2024] Open
Abstract
A microelectrode array (MEA) is a configuration of multiple electrodes that enables the concurrent targeting of multiple sites for extracellular recording and stimulation. By utilizing light pulses or electrical stimulations, MEA recordings unveil the complex patterns of electrical activities that arise from the signaling processes within the retinal network. Here, we present a stepwise approach for using microelectrode arrays (MEAs) for recording action potentials from the mouse retina in response to electrical and light stimuli. We provide detailed techniques accompanied by description of a custom optical system, example recordings, troubleshooting guidelines, and data processing methods including spike sorting and code resources for analyzing light and electrical responses. The comprehensive nature of this paper aims to guide researchers in utilizing MEAs effectively for investigating retinal functionality. In particular, it can be easy to have a MEA experiment fail, but hard to identify the source of the failure. This paper is meant to demystify that process. It includes:•A description of MEA setup, recording, and spike data validation.•A troubleshooting guide for common failure modes in MEA recordings from mouse retina.•Spike detection and sorting to precisely extract distinctive action potential.
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Affiliation(s)
- D L Rathbun
- Department of Ophthalmology, Detroit Institute of Ophthalmology, Henry Ford Health System, Detroit, MI 48202, USA
| | - A Jalligampala
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY 40202, USA
| | - E Zrenner
- Institute for Ophthalmic Research, Eberhard Karls University, 72076 Tübingen, Germany
- Werner Reichardt Centre for Integrative Neuroscience (CIN), 72076 Tübingen, Germany
| | - Z Hosseinzadeh
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
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2
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Qualls KA, Xie W, Zhang J, Lückemeyer DD, Lackey SV, Strong JA, Zhang JM. Mineralocorticoid Receptor Antagonism Reduces Inflammatory Pain Measures in Mice Independent of the Receptors on Sensory Neurons. Neuroscience 2024; 541:64-76. [PMID: 38307407 DOI: 10.1016/j.neuroscience.2024.01.024] [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: 12/04/2023] [Revised: 01/24/2024] [Accepted: 01/29/2024] [Indexed: 02/04/2024]
Abstract
Corticosteroids are commonly used in the treatment of inflammatory low back pain, and their nominal target is the glucocorticoid receptor (GR) to relieve inflammation. They can also have similar potency at the mineralocorticoid receptor (MR). The MR has been shown to be widespread in rodent and human dorsal root ganglia (DRG) neurons and non-neuronal cells, and when MR antagonists are administered during a variety of inflammatory pain models in rats, pain measures are reduced. In this study we selectively knockout (KO) the MR in sensory neurons to determine the role of MR in sensory neurons of the mouse DRG in pain measures as MR antagonism during the local inflammation of the DRG (LID) pain model. We found that MR antagonism using eplerenone reduced evoked mechanical hypersensitivity during LID, but MR KO in paw-innervating sensory neurons only did not. This could be a result of differences between prolonged (MR KO) versus acute (drug) MR block or an indicator that non-neuronal cells in the DRG are driving the effect of MR antagonists. MR KO unmyelinated C neurons are more excitable under normal and inflamed conditions, while MR KO does not affect excitability of myelinated A cells. MR KO in sensory neurons causes a reduction in overall GR mRNA but is protective against reduction of the anti-inflammatory GRα isoform during LID. These effects of MR KO in sensory neurons expanded our understanding of MR's functional role in different neuronal subtypes (A and C neurons), and its interactions with the GR.
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Affiliation(s)
- Katherine A Qualls
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Wenrui Xie
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jietong Zhang
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Debora Denardin Lückemeyer
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Sierra V Lackey
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Judith A Strong
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Jun-Ming Zhang
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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3
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Kaspar C, Ivanenko A, Lehrich J, Klingauf J, Pernice WHP. Biohybrid Photonic Platform for Subcellular Stimulation and Readout of In Vitro Neurons. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2304561. [PMID: 38164885 DOI: 10.1002/advs.202304561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 12/20/2023] [Indexed: 01/03/2024]
Abstract
Targeted manipulation of neural activity via light has become an indispensable tool for gaining insights into the intricate processes governing single neurons and complex neural networks. To shed light onto the underlying interaction mechanisms, it is crucial to achieve precise control of individual neural activity, as well as a spatial read-out resolution on the nanoscale. Here, a versatile photonic platform with subcellular resolution for stimulation and monitoring of in-vitro neurons is demonstrated. Low-loss photonic waveguides are fabricated on glass substrates using nanoimprint lithography and featuring a loss of only -0.9 ± 0.2 dB cm-1 at 489 nm and are combined with optical fiber-based waveguide-access and backside total internal reflection fluorescence microscopy. Neurons are grown on the bio-functionalized photonic chip surface and, expressing the light-sensitive ion channel Channelrhodopsin-2, are stimulated within the evanescent field penetration depth of 57 nm of the biocompatible waveguides. The versatility and cost-efficiency of the platform, along with the possible subcellular resolution, enable tailor-made investigations of neural interaction dynamics with defined spatial control and high throughput.
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Affiliation(s)
- Corinna Kaspar
- Institute of Physics, University of Muenster, Heisenbergstr. 11, 48149, Muenster, Germany
- Center for Soft Nanoscience, University of Muenster, Busso-Peuss-Str. 10, 48149, Muenster, Germany
| | - Alexander Ivanenko
- Center for Soft Nanoscience, University of Muenster, Busso-Peuss-Str. 10, 48149, Muenster, Germany
- Institute of Medical Physics and Biophysics, University of Muenster, Robert-Koch-Str. 31, 48149, Muenster, Germany
| | - Julia Lehrich
- Center for Soft Nanoscience, University of Muenster, Busso-Peuss-Str. 10, 48149, Muenster, Germany
- Institute of Medical Physics and Biophysics, University of Muenster, Robert-Koch-Str. 31, 48149, Muenster, Germany
| | - Jürgen Klingauf
- Center for Soft Nanoscience, University of Muenster, Busso-Peuss-Str. 10, 48149, Muenster, Germany
- Institute of Medical Physics and Biophysics, University of Muenster, Robert-Koch-Str. 31, 48149, Muenster, Germany
| | - Wolfram H P Pernice
- Institute of Physics, University of Muenster, Heisenbergstr. 11, 48149, Muenster, Germany
- Center for Soft Nanoscience, University of Muenster, Busso-Peuss-Str. 10, 48149, Muenster, Germany
- Kirchhoff-Institut for Physics, Heidelberg University, Im Neuenheimer Feld 227, 69120, Heidelberg, Germany
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Davidson CJ, Mascarin AT, Yahya MA, Rubio FJ, Gheidi A. Approaches and considerations of studying neuronal ensembles: a brief review. Front Cell Neurosci 2023; 17:1310724. [PMID: 38155864 PMCID: PMC10752959 DOI: 10.3389/fncel.2023.1310724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 11/27/2023] [Indexed: 12/30/2023] Open
Abstract
First theorized by Hebb, neuronal ensembles have provided a framework for understanding how the mammalian brain operates, especially regarding learning and memory. Neuronal ensembles are discrete, sparsely distributed groups of neurons that become activated in response to a specific stimulus and are thought to provide an internal representation of the world. Beyond the study of region-wide or projection-wide activation, the study of ensembles offers increased specificity and resolution to identify and target specific memories or associations. Neuroscientists interested in the neurobiology of learning, memory, and motivated behavior have used electrophysiological-, calcium-, and protein-based proxies of neuronal activity in preclinical models to better understand the neurobiology of learned and motivated behaviors. Although these three approaches may be used to pursue the same general goal of studying neuronal ensembles, technical differences lead to inconsistencies in the output and interpretation of data. This mini-review highlights some of the methodologies used in electrophysiological-, calcium-, and protein-based studies of neuronal ensembles and discusses their strengths and weaknesses.
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Affiliation(s)
- Cameron J. Davidson
- William Beaumont School of Medicine, Oakland University, Rochester, MI, United States
| | - Alixandria T. Mascarin
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Majd A. Yahya
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - F. Javier Rubio
- Neuronal Ensembles in Addiction Section, Behavioral Neuroscience Research Branch, Intramural Research Program/National Institute on Drug Abuse/National Institutes of Health, Bethesda, MD, United States
| | - Ali Gheidi
- Department of Biomedical Sciences, Mercer University, Macon, GA, United States
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Ghosh S, Dahiya M, Kumar A, Bheri M, Pandey GK. Calcium imaging: a technique to monitor calcium dynamics in biological systems. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2023; 29:1777-1811. [PMID: 38222278 PMCID: PMC10784449 DOI: 10.1007/s12298-023-01405-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 12/07/2023] [Accepted: 12/11/2023] [Indexed: 01/16/2024]
Abstract
Calcium ion (Ca2+) is a multifaceted signaling molecule that acts as an important second messenger. During the course of evolution, plants and animals have developed Ca2+ signaling in order to respond against diverse stimuli, to regulate a large number of physiological and developmental pathways. Our understanding of Ca2+ signaling and its components in physiological phenomena ranging from lower to higher organisms, and from single cell to multiple tissues has grown exponentially. The generation of Ca2+ transients or signatures for various stress factor is a well-known mechanism adopted in plant and animal systems. However, the decoding of such remarkable signatures is an uphill task and is always an interesting goal for the scientific community. In the past few decades, studies on the concentration and dynamics of intracellular Ca2+ are significantly increasing and have become a trend in modern biology. The advancement in approaches from Ca2+ binding dyes to in vivo Ca2+ imaging through the use of Ca2+ biosensors to achieve spatio-temporal resolution in micro and milliseconds range, provide us phenomenal opportunities to study live cell Ca2+ imaging or dynamics. Here, we describe the usage, improvement and advancement of Ca2+ based dyes, genetically encoded probes and sensors to achieve extraordinary Ca2+ imaging in plants and animals. Graphical abstract
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Affiliation(s)
- Soma Ghosh
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, 110021 India
| | - Monika Dahiya
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, 110021 India
| | - Amit Kumar
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, 110021 India
| | - Malathi Bheri
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, 110021 India
| | - Girdhar K. Pandey
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, 110021 India
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Genovese F, Xu J, Tizzano M, Reisert J. Quantifying Peripheral Modulation of Olfaction by Trigeminal Agonists. J Neurosci 2023; 43:7958-7966. [PMID: 37813571 PMCID: PMC10669757 DOI: 10.1523/jneurosci.0489-23.2023] [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: 03/03/2023] [Revised: 08/15/2023] [Accepted: 09/06/2023] [Indexed: 10/17/2023] Open
Abstract
In the mammalian nose, two chemosensory systems, the trigeminal and the olfactory mediate the detection of volatile chemicals. Most odorants are able to activate the trigeminal system, and vice versa, most trigeminal agonists activate the olfactory system as well. Although these two systems constitute two separate sensory modalities, trigeminal activation modulates the neural representation of an odor. The mechanisms behind the modulation of olfactory response by trigeminal activation are still poorly understood. We addressed this question by looking at the olfactory epithelium (OE), where olfactory sensory neurons (OSNs) and trigeminal sensory fibers co-localize and where the olfactory signal is generated. Our study was conducted in a mouse model. Both sexes, males and females, were included. We characterize the trigeminal activation in response to five different odorants by measuring intracellular Ca2+ changes from primary cultures of trigeminal neurons (TGNs). We also measured responses from mice lacking TRPA1 and TRPV1 channels known to mediate some trigeminal responses. Next, we tested how trigeminal activation affects the olfactory response in the olfactory epithelium using electro-olfactogram (EOG) recordings from wild-type (WT) and TRPA1/V1-knock out (KO) mice. The trigeminal modulation of the olfactory response was determined by measuring responses to the odorant, 2-phenylethanol (PEA), an odorant with little trigeminal potency after stimulation with a trigeminal agonist. Trigeminal agonists induced a decrease in the EOG response to PEA, which depended on the level of TRPA1 and TRPV1 activation induced by the trigeminal agonist. This suggests that trigeminal activation can alter odorant responses even at the earliest stage of the olfactory sensory transduction.SIGNIFICANCE STATEMENT Most odorants reaching the olfactory epithelium (OE) can simultaneously activate olfactory and trigeminal systems. Although these two systems constitute two separate sensory modalities, trigeminal activation can alter odor perception. Here, we analyzed the trigeminal activity induced by different odorants proposing an objective quantification of their trigeminal potency independent from human perception. We show that trigeminal activation by odorants reduces the olfactory response in the olfactory epithelium and that such modulation correlates with the trigeminal potency of the trigeminal agonist. These results show that the trigeminal system impacts the olfactory response from its earliest stage.
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Affiliation(s)
| | - Jiang Xu
- Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104
| | - Marco Tizzano
- Monell Chemical Senses Center, Philadelphia, Pennsylvania 19104
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7
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Biechele-Speziale D, Camarillo M, Martin NR, Biechele-Speziale J, Lein PJ, Plavicki JS. Assessing CaMPARI as new approach methodology for evaluating neurotoxicity. Neurotoxicology 2023; 97:109-119. [PMID: 37244562 PMCID: PMC10527633 DOI: 10.1016/j.neuro.2023.05.013] [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: 03/24/2023] [Revised: 05/12/2023] [Accepted: 05/23/2023] [Indexed: 05/29/2023]
Abstract
Developmental exposure to environmental toxicants has been linked to the onset of neurological disorders and diseases. Despite substantial advances in the field of neurotoxicology, there remain significant knowledge gaps in our understanding of cellular targets and molecular mechanisms that mediate the neurotoxicological endpoints associated with exposure to both legacy contaminants and emerging contaminants of concern. Zebrafish are a powerful neurotoxicological model given their high degree sequence conservation with humans and the similarities they share with mammals in micro- and macro-level brain structures. Many zebrafish studies have effectively utilized behavioral assays to predict the neurotoxic potential of different compounds, but behavioral phenotypes are rarely able to predict the brain structures, cell types, or mechanisms affected by chemical exposures. Calcium-modulated photoactivatable ratiometric integrator (CaMPARI), a recently developed genetically-encoded calcium indicator, undergoes a permanent green to red switch in the presence of elevated intracellular Ca2+ concentrations and 405-nm light, which allows for a "snapshot" of brain activity in freely-swimming larvae. To determine whether behavioral results are predictive of patterns of neuronal activity, we assessed the effects of three common neurotoxicants, ethanol, 2,2',3,5',6-pentachlorobiphenyl (PCB 95), and monoethylhexyl phthalate (MEHP), on both brain activity and behavior by combining the behavioral light/dark assay with CaMPARI imaging. We demonstrate that brain activity profiles and behavioral phenotypes are not always concordant and, therefore, behavior alone is not sufficient to understand how toxicant exposure affects neural development and network dynamics. We conclude that pairing behavioral assays with functional neuroimaging tools such as CaMPARI provides a more comprehensive understanding of the neurotoxic endpoints of compounds while still offering a relatively high throughput approach to toxicity testing.
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Affiliation(s)
- Dana Biechele-Speziale
- Department of Chemistry, Brown University, Providence, RI, USA; Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA
| | - Manuel Camarillo
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA
| | - Nathan R Martin
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA
| | | | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Jessica S Plavicki
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA.
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Lee M, Landers K, Chan J. Activity-Based Photoacoustic Probes for Detection of Disease Biomarkers beyond Oncology. ACS BIO & MED CHEM AU 2023; 3:223-232. [PMID: 37363076 PMCID: PMC10288495 DOI: 10.1021/acsbiomedchemau.3c00009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/27/2023] [Accepted: 02/28/2023] [Indexed: 06/28/2023]
Abstract
The earliest activity-based photoacoustic (PA) probes were developed as diagnostic agents for cancer. Since this seminal work over a decade ago that specifically targeted matrix metalloproteinase-2, PA instrumentation, dye platforms, and probe designs have advanced considerably, allowing for the detection of an impressive list of cancer types. However, beyond imaging for oncology purposes, the ability to selectively visualize a given disease biomarker, which can range from aberrant enzymatic activity to the overproduction of reactive small molecules, is also being exploited to study a myriad of noncancerous disease states. In this review, we have assembled a collection of recent papers to highlight the design principles that enable activity-based sensing via PA imaging with respect to biomarker identification and strategies to trigger probe activation under specific conditions.
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Chen HJC, Mazzaferro S, Tian T, Mali I, Merkle FT. Differentiation, Transcriptomic Profiling, and Calcium Imaging of Human Hypothalamic Neurons. Curr Protoc 2023; 3:e786. [PMID: 37272700 PMCID: PMC7614736 DOI: 10.1002/cpz1.786] [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] [Indexed: 06/06/2023]
Abstract
Neurons in the hypothalamus orchestrate homeostatic physiological processes and behaviors essential for life. Human pluripotent stem cells (hPSCs) can be differentiated into many types of hypothalamic neurons, progenitors, and glia. This updated unit includes published studies and protocols with new advances in the differentiation, maturation, and interrogation by transcriptomic profiling and calcium imaging of human hypothalamic cell populations. Specifically, new methods to freeze and thaw hypothalamic progenitors after they have been patterned and before substantial neurogenesis has occurred are provided that will facilitate experimental flexibility and planning. Also included are updated recipes and protocols for neuronal maturation, with details on the equipment and methods for examining their transcriptomic response and cell-autonomous properties in culture in the presence of synaptic blockers. Together, these protocols facilitate the adoption and use of this model system for fundamental biological discovery and therapeutic translation to human diseases such as obesity, diabetes, sleep disorders, infertility, and chronic stress. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: hPSC maintenance Basic Protocol 2: Hypothalamic neuron differentiation Support Protocol 1: Cortical neuron (control) differentiation Basic Protocol 3: Neuronal maturation Support Protocol 2: Cryopreservation and thawing of neuronal progenitors Support Protocol 3: Quality control: Confirmation of hypothalamic patterning and neurogenesis Support Protocol 4: Bulk RNA sequencing of hypothalamic cultures Basic Protocol 4: Calcium imaging of hypothalamic neurons using Fura-2 AM Alternate Protocol: Calcium imaging of green fluorescent hypothalamic neurons using Rhod-3 AM.
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Affiliation(s)
- Hsiao-Jou Cortina Chen
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke’s Hospital, Cambridge, UK
- Wellcome Trust–Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Simone Mazzaferro
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke’s Hospital, Cambridge, UK
- Wellcome Trust–Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Tian Tian
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke’s Hospital, Cambridge, UK
- Wellcome Trust–Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Iman Mali
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke’s Hospital, Cambridge, UK
| | - Florian T. Merkle
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke’s Hospital, Cambridge, UK
- Wellcome Trust–Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
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Federica G, Jiang X, Marco T, Johannes R. Quantifying peripheral modulation of olfaction by trigeminal agonists. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.13.532477. [PMID: 36993353 PMCID: PMC10054987 DOI: 10.1101/2023.03.13.532477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
In the mammalian nose, two chemosensory systems, the trigeminal and the olfactory mediate the detection of volatile chemicals. Most odorants in fact are able to activate the trigeminal system, and vice versa, most trigeminal agonists activate the olfactory system as well. Although these two systems constitute two separate sensory modalities, trigeminal activation modulates the neural representation of an odor. The mechanisms behind the modulation of olfactory response by trigeminal activation are still poorly understood. In this study, we addressed this question by looking at the olfactory epithelium, where olfactory sensory neurons and trigeminal sensory fibers co-localize and where the olfactory signal is generated. We characterize the trigeminal activation in response to five different odorants by measuring intracellular Ca2+ changes from primary cultures of trigeminal neurons (TGNs). We also measured responses from mice lacking TRPA1 and TRPV1 channels known to mediate some trigeminal responses. Next, we tested how trigeminal activation affects the olfactory response in the olfactory epithelium using electro-olfactogram (EOG) recordings from WT and TRPA1/V1-KO mice. The trigeminal modulation of the olfactory response was determined by measuring responses to the odorant, 2-phenylethanol (PEA), an odorant with little trigeminal potency after stimulation with a trigeminal agonist. Trigeminal agonists induced a decrease in the EOG response to PEA, which depended on the level of TRPA1 and TRPV1 activation induced by the trigeminal agonist. This suggests that trigeminal activation can alter odorant responses even at the earliest stage of the olfactory sensory transduction.
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Affiliation(s)
| | - Xu Jiang
- Monell Chemical Senses Center, 19104 Philadelphia, PA, USA
| | - Tizzano Marco
- Monell Chemical Senses Center, 19104 Philadelphia, PA, USA
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11
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Allan C, Tayagui A, Hornung R, Nock V, Meisrimler CN. A dual-flow RootChip enables quantification of bi-directional calcium signaling in primary roots. FRONTIERS IN PLANT SCIENCE 2023; 13:1040117. [PMID: 36704158 PMCID: PMC9871814 DOI: 10.3389/fpls.2022.1040117] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 12/13/2022] [Indexed: 06/18/2023]
Abstract
One sentence summary: Bi-directional-dual-flow-RootChip to track calcium signatures in Arabidopsis primary roots responding to osmotic stress. Plant growth and survival is fundamentally linked with the ability to detect and respond to abiotic and biotic factors. Cytosolic free calcium (Ca2+) is a key messenger in signal transduction pathways associated with a variety of stresses, including mechanical, osmotic stress and the plants' innate immune system. These stresses trigger an increase in cytosolic Ca2+ and thus initiate a signal transduction cascade, contributing to plant stress adaptation. Here we combine fluorescent G-CaMP3 Arabidopsis thaliana sensor lines to visualise Ca2+ signals in the primary root of 9-day old plants with an optimised dual-flow RootChip (dfRC). The enhanced polydimethylsiloxane (PDMS) bi-directional-dual-flow-RootChip (bi-dfRC) reported here adds two adjacent inlet channels at the base of the observation chamber, allowing independent or asymmetric chemical stimulation at either the root differentiation zone or tip. Observations confirm distinct early spatio-temporal patterns of salinity (sodium chloride, NaCl) and drought (polyethylene glycol, PEG)-induced Ca2+ signals throughout different cell types dependent on the first contact site. Furthermore, we show that the primary signal always dissociates away from initially stimulated cells. The observed early signaling events induced by NaCl and PEG are surprisingly complex and differ from long-term changes in cytosolic Ca2+ reported in roots. Bi-dfRC microfluidic devices will provide a novel approach to challenge plant roots with different conditions simultaneously, while observing bi-directionality of signals. Future applications include combining the bi-dfRC with H2O2 and redox sensor lines to test root systemic signaling responses to biotic and abiotic factors.
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Affiliation(s)
- Claudia Allan
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Ayelen Tayagui
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
- Department of Electrical and Computer Engineering, University of Canterbury, Christchurch, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand
| | | | - Volker Nock
- Department of Electrical and Computer Engineering, University of Canterbury, Christchurch, New Zealand
- MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand
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12
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Fekete Z, Zátonyi A, Kaszás A, Madarász M, Slézia A. Transparent neural interfaces: challenges and solutions of microengineered multimodal implants designed to measure intact neuronal populations using high-resolution electrophysiology and microscopy simultaneously. MICROSYSTEMS & NANOENGINEERING 2023; 9:66. [PMID: 37213820 PMCID: PMC10195795 DOI: 10.1038/s41378-023-00519-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 02/03/2023] [Accepted: 03/01/2023] [Indexed: 05/23/2023]
Abstract
The aim of this review is to present a comprehensive overview of the feasibility of using transparent neural interfaces in multimodal in vivo experiments on the central nervous system. Multimodal electrophysiological and neuroimaging approaches hold great potential for revealing the anatomical and functional connectivity of neuronal ensembles in the intact brain. Multimodal approaches are less time-consuming and require fewer experimental animals as researchers obtain denser, complex data during the combined experiments. Creating devices that provide high-resolution, artifact-free neural recordings while facilitating the interrogation or stimulation of underlying anatomical features is currently one of the greatest challenges in the field of neuroengineering. There are numerous articles highlighting the trade-offs between the design and development of transparent neural interfaces; however, a comprehensive overview of the efforts in material science and technology has not been reported. Our present work fills this gap in knowledge by introducing the latest micro- and nanoengineered solutions for fabricating substrate and conductive components. Here, the limitations and improvements in electrical, optical, and mechanical properties, the stability and longevity of the integrated features, and biocompatibility during in vivo use are discussed.
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Affiliation(s)
- Z. Fekete
- Research Group for Implantable Microsystems, Faculty of Information Technology & Bionics, Pázmány Péter Catholic University, Budapest, Hungary
- Institute of Cognitive Neuroscience & Psychology, Eotvos Lorand Research Network, Budapest, Hungary
| | - A. Zátonyi
- Research Group for Implantable Microsystems, Faculty of Information Technology & Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - A. Kaszás
- Mines Saint-Etienne, Centre CMP, Département BEL, F - 13541 Gardanne, France
- Institut de Neurosciences de la Timone, CNRS UMR 7289 & Aix-Marseille Université, 13005 Marseille, France
| | - M. Madarász
- János Szentágothai PhD Program of Semmelweis University, Budapest, Hungary
- BrainVision Center, Budapest, Hungary
| | - A. Slézia
- Institut de Neurosciences de la Timone, CNRS UMR 7289 & Aix-Marseille Université, 13005 Marseille, France
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13
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Bye LJ, Finol-Urdaneta RK, Adams DJ. Calcium Imaging of Non-adherent Cells. Methods Mol Biol 2023; 2644:361-369. [PMID: 37142934 DOI: 10.1007/978-1-0716-3052-5_23] [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: 05/06/2023]
Abstract
Live-cell imaging can reveal dynamic and multimodal cell signaling by monitoring calcium flux. Spatiotemporal changes in Ca2+ concentrations instigate specific downstream processes and by categorizing these events, we can examine the language cells use to communicate both to themselves and with each other. Thus, calcium imaging is an understandably popular and versatile technique that relies on high-resolution optical data as measured by fluorescence intensity. This is executed with relative ease on adherent cells, as changes in fluorescence intensity can be monitored over time in fixed regions of interest. However, perfusion of non-adherent or mildly adherent cells leads to their mechanical displacement thereby hindering the spatial resolution of fluorescence intensity changes through time. Here we provide details of a simple and cost-effective protocol using gelatin to prevent cell dislodgement during the solution exchanges that occur during recording.
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Affiliation(s)
- Lydia J Bye
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia
| | - Rocio K Finol-Urdaneta
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia.
| | - David J Adams
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia
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14
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Investigating the effect of Shenmai injection on cardiac electrophysiology and calcium signaling using human-induced pluripotent stem cell-derived cardiomyocytes. Biochem Biophys Rep 2022; 33:101407. [PMID: 36593870 PMCID: PMC9803683 DOI: 10.1016/j.bbrep.2022.101407] [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: 10/12/2022] [Revised: 11/21/2022] [Accepted: 12/06/2022] [Indexed: 12/27/2022] Open
Abstract
Traditional Chinese medicine injection (TCMI) refers to the use of modern technology to make Chinese patent medicines in injectable forms, which shorten the onset time of the traditional Chinese medicine (TCM). Although there have been clinical cases in which Shenmai injection (SMI) was used to treat cardiovascular diseases (CVDs), there are no pharmacological experiments that investigate the efficacy of the drug in vitro or the underlying mechanisms. Aim of the study We aimed to systemically evaluate the efficacy and investigate the mechanisms of SMI in modulating electrophysiology and calcium (Ca2+) signaling using a microelectrode array (MEA) and a genetically encoded Ca2+ indicator, GCaMP6s, respectively, in human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Materials and methods A MEA system was employed to record field potentials (FPs) in hiPSC-CMs. The QT interval is corrected by the RR interval, the reciprocal of the beating rate. GCaMP6s was used to measure Ca2+ signaling in hiPSC-CMs. Meanwhile, the transcriptome changes in hiPSC-CMs treated with 2% SMI were examined using RNAseq. In addition, the ingredients of SMI were investigated using liquid chromatography-mass spectrometry (LC-MS). Results It was found that 0.5%, 1%, and 2% (v/v) SMIs could increase corrected QT (QTc) but did not change other FP parameters. GCaMP6s was successfully applied to measure the chronic function of SMI. The full width at half maximum (FWHM), rise time, and decay time significantly decreased after treatment with SMI for 1 h and 24 h, whereas an increased Ca2+ transient frequency was observed. Conclusions We first used the Ca2+ indicator to measure the chronic effects of TCM. We found that SMI treatment can modulate electrophysiology and calcium signaling and regulate oxidative phosphorylation, cardiac muscle contraction, and the cell cycle pathway in hiPSC-CMs.
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Key Words
- AP, action potentials
- CCK-8, cell counting kit-8 assay
- CVDs, cardiovascular diseases
- Calcium indicators
- ECC, excitation–contraction coupling
- ECG, electrocardiogram
- FP, field potential
- FWHM, full width at half maximum
- Ikr, rapidly activating delayed rectifier potassium current
- LC-MS, liquid chromatography-mass spectrometry
- MEA, microelectrode array
- Polytetrafluoroethylene, PTFE
- QTc, corrected QT
- QoL, quality of life
- SMI, Shenmai injection
- Shenmai injection
- TCM, traditional Chinese medicine
- TCMI, traditional Chinese medicine injections
- Traditional Chinese medicine
- hiPSC-CMs
- hiPSC-CMs, human-induced pluripotent stem cell-derived cardiomyocytes
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15
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Jönsson M, Scheffel J, Larsson E, Möller M, Rossi G, Lundqvist M, Rockberg J, Uhlén M, Tegel H, Kanje S, Hober S. CaRA - A multi-purpose phage display library for selection of calcium-regulated affinity proteins. N Biotechnol 2022; 72:159-167. [PMID: 36450334 DOI: 10.1016/j.nbt.2022.11.005] [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: 07/04/2022] [Revised: 11/02/2022] [Accepted: 11/26/2022] [Indexed: 11/29/2022]
Abstract
Protein activity regulated by interactions with metal ions can be utilized for many different purposes, including biological therapies and bioprocessing, among others. Calcium ions are known to interact with the frequently occurring EF-hand motif, which can alter protein activity upon binding through an induced conformational change. The calcium-binding loop of the EF-hand motif has previously been introduced into a small protein domain derived from staphylococcal Protein A in a successful effort to render antibody binding dependent on calcium. Presented here, is a combinatorial library for calcium-regulated affinity, CaRA, based on this domain. CaRA is the first alternative scaffold library designed to achieve novel target specificities with metal-dependent binding. From this library, several calcium-dependent binders could be isolated through phage display campaigns towards a set of unrelated target proteins (IgE Cε3-Cε4, TNFα, IL23, scFv, tPA, PCSK9 and HER3) useful for distinct applications. Overall, these monomeric CaRA variants showed high stability and target affinities within the nanomolar range. They displayed considerably higher melting temperatures in the presence of 1 mM calcium compared to without calcium. Further, all discovered binders proved to be calcium-dependent, with the great majority showing complete lack of target binding in the absence of calcium. As demonstrated, the CaRA library is highly capable of providing protein-binding domains with calcium-dependent behavior, independent of the type of target protein. These binding domains could subsequently be of great use in gentle protein purification or as novel therapeutic modalities.
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Affiliation(s)
- Malin Jönsson
- Department of Protein Science, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Julia Scheffel
- Department of Protein Science, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Emma Larsson
- Department of Protein Science, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Marit Möller
- Department of Protein Science, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Gabriella Rossi
- Department of Protein Science, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Magnus Lundqvist
- Department of Protein Science, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Johan Rockberg
- Department of Protein Science, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Mathias Uhlén
- Department of Protein Science, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Hanna Tegel
- Department of Protein Science, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Sara Kanje
- Department of Protein Science, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Sophia Hober
- Department of Protein Science, KTH-Royal Institute of Technology, SE-10691 Stockholm, Sweden.
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16
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Aryal SP, Xia M, Ortinski PI, Richards CI. Study of Calcium Signaling in Astrocytes with a Novel Endoplasmic Reticulum-Targeted GCaMP Sensor. Curr Protoc 2022; 2:e491. [PMID: 35938843 PMCID: PMC9373517 DOI: 10.1002/cpz1.491] [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] [Indexed: 06/15/2023]
Abstract
The endoplasmic reticulum (ER), the major organelle for the storage of Ca2+ , maintains a concentration of Ca2+ much higher than in the cytosol or other subcellular organelles, such as the mitochondria. A variety of tools have been developed for measuring Ca2+ activity in neuronal and glial cells, but most of these sensors target either the plasma membrane (PM) or the cytosol. Though these sensors are important for measuring Ca2+ transients, they lack the capability to measure activity in the periphery of the ER or to measure low-amplitude events resulting from Ca2+ exchange between the ER and other organelles, such as the mitochondria. We recently developed an ER-targeted GCaMP6f anchored to the cytosolic side of the ER that can measure minute calcium exchange occurring in this region. In this article, we discuss detailed methods to characterize the ER-GCaMP6f sensor, utilize it for calcium imaging in cultured astrocytes, and assess its expression and calcium imaging in astrocytes in rodent brains. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Expression and characterization of ER-GCaMP6f Support Protocol 1: ER-GCaMP6f-expressing stable cell line generation Basic Protocol 2: In vitro calcium imaging with ER-GCaMP6f Support Protocol 2: Imaging of drug-induced calcium activity Alternate Protocol 1: Transduction of astrocytes with ER-GCaMP6f AAV Alternate Protocol 2: Calcium imaging of astrocytes with Fluo-4 AM Basic Protocol 3: In vivo ER-GCaMP6f expression and slice calcium imaging Support Protocol 3: Pharmacological studies with 2-APB in brain slices.
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Affiliation(s)
- Surya P Aryal
- Department of Chemistry, University of Kentucky, Lexington, Kentucky
| | - Mengfan Xia
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky
| | - Pavel I Ortinski
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky
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17
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Rose P, Klioutchnikov A, Wallace DJ, Greenberg DS, Kerr JND, Sawinski J. Measurement of arbitrary scan patterns for correction of imaging distortions in laser scanning microscopy. BIOMEDICAL OPTICS EXPRESS 2022; 13:3983-3992. [PMID: 35991933 PMCID: PMC9352294 DOI: 10.1364/boe.454155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 03/17/2022] [Accepted: 03/20/2022] [Indexed: 06/15/2023]
Abstract
Laser scanning microscopy requires beam steering through relay and focusing optics at sub-micron precision. In light-weight mobile systems, such as head mounted multiphoton microscopes, distortion and imaging plane curvature management is unpractical due to the complexity of required optic compensation. Thus, the resulting scan pattern limits anatomical fidelity and decreases analysis algorithm efficiency. Here, we present a technique that reconstructs the three-dimensional scan path only requiring translation of a simple fluorescent test probe. Our method is applicable to any type of scanning instrument with sectioning capabilities without prior assumptions regarding origin of imaging deviations. Further, we demonstrate that the obtained scan pattern allows analysis of these errors, and allows to restore anatomical accuracy relevant for complementary methods such as motion correction, further enhancing spatial registration and feature extraction.
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18
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Iwama T, Inoue KY, Shiku H. Fabrication of High-Density Vertical Closed Bipolar Electrode Arrays by Carbon Paste Filling Method for Two-Dimensional Chemical Imaging. Anal Chem 2022; 94:8857-8866. [PMID: 35700401 DOI: 10.1021/acs.analchem.1c05354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this study, a carbon paste filling method was proposed as a simple strategy for fabricating high-density bipolar electrode (BPE) arrays for bipolar electrochemical microscopy (BEM). High spatiotemporal resolution imaging was achieved using the fabricated BPE array. BEM, which is an emerging microscopic system in recent years, achieves label-free and high spatiotemporal resolution imaging of molecular distributions using high-density BPE arrays and electrochemiluminescence (ECL) signals. We devised a simple method to fabricate a BPE array by filling a porous plate with carbon paste and succeeded in fabricating a high-density BPE array (15 μm pitch). After a detailed observation of the surface of the BPE array using a scanning electron microscope, the basic electrochemical and ECL emission characteristics were evaluated using potassium ferricyanide solution as a sample solution. Moreover, inflow imaging of the sample molecules was conducted to evaluate the imaging ability of the prepared BPE array. In addition, Prussian Blue containing carbon ink was applied to the sample solution side of the BPE array to provide catalytic activity to hydrogen peroxide, and the quantification and inflow imaging of hydrogen peroxide by ECL signals was achieved. This simple fabrication method of the BPE array can accelerate the research and development of BEM. Furthermore, hydrogen peroxide imaging by BEM is an important milestone for achieving bioimaging with high spatiotemporal resolution such as biomolecule imaging using enzymes.
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Affiliation(s)
- Tomoki Iwama
- Graduate School of Environmental Studies, Tohoku University, 6-6-11 Aramaki Aoba, Aoba, Sendai, Miyagi 980-8579, Japan
| | - Kumi Y Inoue
- Graduate School of Environmental Studies, Tohoku University, 6-6-11 Aramaki Aoba, Aoba, Sendai, Miyagi 980-8579, Japan.,Center for Basic Education, Faculty of Engineering, Graduate Faculty of Interdisciplinary Research, University of Yamanashi, 4-3-11 Takeda, Kofu 400-8511, Japan
| | - Hitoshi Shiku
- Graduate School of Environmental Studies, Tohoku University, 6-6-11 Aramaki Aoba, Aoba, Sendai, Miyagi 980-8579, Japan.,Graduate School of Engineering, Tohoku University, 6-6-11 Aramaki Aoba, Aoba, Sendai, Miyagi 980-8579, Japan
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19
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Fallah HP, Ahuja E, Lin H, Qi J, He Q, Gao S, An H, Zhang J, Xie Y, Liang D. A Review on the Role of TRP Channels and Their Potential as Drug Targets_An Insight Into the TRP Channel Drug Discovery Methodologies. Front Pharmacol 2022; 13:914499. [PMID: 35685622 PMCID: PMC9170958 DOI: 10.3389/fphar.2022.914499] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 04/27/2022] [Indexed: 01/13/2023] Open
Abstract
Transient receptor potential (TRP) proteins are a large group of ion channels that control many physiological functions in our body. These channels are considered potential therapeutic drug targets for various diseases such as neurological disorders, cancers, cardiovascular disease, and many more. The Nobel Prize in Physiology/Medicine in the year 2021 was awarded to two scientists for the discovery of TRP and PIEZO ion channels. Improving our knowledge of technologies for their study is essential. In the present study, we reviewed the role of TRP channel types in the control of normal physiological functions as well as disease conditions. Also, we discussed the current and novel technologies that can be used to study these channels successfully. As such, Flux assays for detecting ionic flux through ion channels are among the core and widely used tools for screening drug compounds. Technologies based on these assays are available in fully automated high throughput set-ups and help detect changes in radiolabeled or non-radiolabeled ionic flux. Aurora’s Ion Channel Reader (ICR), which works based on label-free technology of flux assay, offers sensitive, accurate, and reproducible measurements to perform drug ranking matching with patch-clamp (gold standard) data. The non-radiolabeled trace-based flux assay coupled with the ICR detects changes in various ion types, including potassium, calcium, sodium, and chloride channels, by using appropriate tracer ions. This technology is now considered one of the very successful approaches for analyzing ion channel activity in modern drug discovery. It could be a successful approach for studying various ion channels and transporters, including the different members of the TRP family of ion channels.
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Affiliation(s)
- Hamideh P Fallah
- Aurora Biomed Inc., Vancouver, BC, Canada
- *Correspondence: Hamideh P Fallah,
| | - Ekta Ahuja
- Aurora Biomed Inc., Vancouver, BC, Canada
| | | | - Jinlong Qi
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Qian He
- Aurora Discovery Inc., Foshan, China
| | - Shan Gao
- Aurora Discovery Inc., Foshan, China
| | | | | | | | - Dong Liang
- Aurora Biomed Inc., Vancouver, BC, Canada
- Aurora Discovery Inc., Foshan, China
- Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
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20
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Wu SY, Shen Y, Shkolnikov I, Campbell RE. Fluorescent Indicators For Biological Imaging of Monatomic Ions. Front Cell Dev Biol 2022; 10:885440. [PMID: 35573682 PMCID: PMC9093666 DOI: 10.3389/fcell.2022.885440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/04/2022] [Indexed: 11/13/2022] Open
Abstract
Monatomic ions play critical biological roles including maintaining the cellular osmotic pressure, transmitting signals, and catalyzing redox reactions as cofactors in enzymes. The ability to visualize monatomic ion concentration, and dynamic changes in the concentration, is essential to understanding their many biological functions. A growing number of genetically encodable and synthetic indicators enable the visualization and detection of monatomic ions in biological systems. With this review, we aim to provide a survey of the current landscape of reported indicators. We hope this review will be a useful guide to researchers who are interested in using indicators for biological applications and to tool developers seeking opportunities to create new and improved indicators.
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Affiliation(s)
- Sheng-Yi Wu
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Yi Shen
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Irene Shkolnikov
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
- Department of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Robert E. Campbell
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
- Department of Chemistry, The University of Tokyo, Tokyo, Japan
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21
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Absolute measurement of cellular activities using photochromic single-fluorophore biosensors and intermittent quantification. Nat Commun 2022; 13:1850. [PMID: 35387971 PMCID: PMC8986857 DOI: 10.1038/s41467-022-29508-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 03/18/2022] [Indexed: 11/20/2022] Open
Abstract
Genetically-encoded biosensors based on a single fluorescent protein are widely used to visualize analyte levels or enzymatic activities in cells, though usually to monitor relative changes rather than absolute values. We report photochromism-enabled absolute quantification (PEAQ) biosensing, a method that leverages the photochromic properties of biosensors to provide an absolute measure of the analyte concentration or activity. We develop proof-of-concept photochromic variants of the popular GCaMP family of Ca2+ biosensors, and show that these can be used to resolve dynamic changes in the absolute Ca2+ concentration in live cells. We also develop intermittent quantification, a technique that combines absolute aquisitions with fast fluorescence acquisitions to deliver fast but fully quantitative measurements. We also show how the photochromism-based measurements can be expanded to situations where the absolute illumination intensities are unknown. In principle, PEAQ biosensing can be applied to other biosensors with photochromic properties, thereby expanding the possibilities for fully quantitative measurements in complex and dynamic systems. Biosensors often report relative rather than absolute values. Here the authors report a method that utilises the photochromic properties of biosensors to provide an absolute measure of the analyte concentration or activity: photochromism-enabled absolute quantification (PEAQ) biosensing.
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22
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Brandner S, Aicher S, Schroeter S, Swierzy I, Kinfe TM, Buchfelder M, Maslarova A, Stadlbauer A. Real-time imaging of glutamate transients in the extracellular space of acute human brain slices using a single-wavelength glutamate fluorescence nanosensor. Sci Rep 2022; 12:3926. [PMID: 35273260 PMCID: PMC8913701 DOI: 10.1038/s41598-022-07940-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 02/22/2022] [Indexed: 12/12/2022] Open
Abstract
Glutamate is the most important excitatory neurotransmitter in the brain. The ability to assess glutamate release and re-uptake with high spatial and temporal resolution is crucial to understand the involvement of this primary excitatory neurotransmitter in both normal brain function and different neurological disorders. Real-time imaging of glutamate transients by fluorescent nanosensors has been accomplished in rat brain slices. We performed for the first time single-wavelength glutamate nanosensor imaging in human cortical brain slices obtained from patients who underwent epilepsy surgery. The glutamate fluorescence nanosensor signals of the electrically stimulated human cortical brain slices showed steep intensity increase followed by an exponential decrease. The spatial distribution and the time course of the signal were in good agreement with the position of the stimulation electrode and the dynamics of the electrical stimulation, respectively. Pharmacological manipulation of glutamate release and reuptake was associated with corresponding changes in the glutamate fluorescence nanosensor signals. We demonstrated that the recently developed fluorescent nanosensors for glutamate allow to detect neuronal activity in acute human cortical brain slices with high spatiotemporal precision. Future application to tissue samples from different pathologies may provide new insights into pathophysiology without the limitations of an animal model.
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Affiliation(s)
- Sebastian Brandner
- Department of Neurosurgery, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany.
| | - Simon Aicher
- Department of Neurosurgery, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Sarah Schroeter
- Department of Neurosurgery, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany.,Center for Musculoskeletal Surgery Osnabrück (OZMC), Klinikum Osnabrück, Osnabrück, Germany
| | - Izabela Swierzy
- Department of Neurosurgery, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Thomas M Kinfe
- Department of Neurosurgery, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany.,Division of Functional Neurosurgery and Stereotaxy, University Hospital Erlangen, Erlangen, Germany
| | - Michael Buchfelder
- Department of Neurosurgery, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Anna Maslarova
- Department of Neurosurgery, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany
| | - Andreas Stadlbauer
- Department of Neurosurgery, University Hospital Erlangen, Schwabachanlage 6, 91054, Erlangen, Germany.,Institute of Medical Radiology, University Clinic St. Pölten, Karl Landsteiner University of Health Sciences, St. Pölten, Austria
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23
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Iseppon F, Linley JE, Wood JN. Calcium imaging for analgesic drug discovery. NEUROBIOLOGY OF PAIN 2022; 11:100083. [PMID: 35079661 PMCID: PMC8777277 DOI: 10.1016/j.ynpai.2021.100083] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/17/2021] [Accepted: 12/27/2021] [Indexed: 11/24/2022]
Abstract
Calcium imaging is an efficient way to dissect the activity of neurons in vivo. GCaMP indicators can be expressed in specific cell populations for in vivo imaging. Pain research have benefitted greatly from these features in the recent decade. Preclinical research is shifting towards the analysis of pain models and mechanisms. In vivo calcium imaging is the ideal tool for an efficient drug discovery paradigm.
Somatosensation and pain are complex phenomena involving a rangeofspecialised cell types forming different circuits within the peripheral and central nervous systems. In recent decades, advances in the investigation of these networks, as well as their function in sensation, resulted from the constant evolution of electrophysiology and imaging techniques to allow the observation of cellular activity at the population level both in vitro and in vivo. Genetically encoded indicators of neuronal activity, combined with recent advances in DNA engineering and modern microscopy, offer powerful tools to dissect and visualise the activity of specific neuronal subpopulations with high spatial and temporal resolution. In recent years various groups developed in vivo imaging techniques to image calcium transients in the dorsal root ganglia, the spinal cord and the brain of anesthetised and awake, behaving animals to address fundamental questions in both the physiology and pathophysiology of somatosensation and pain. This approach, besides giving unprecedented details on the circuitry of innocuous and painful sensation, can be a very powerful tool for pharmacological research, from the characterisation of new potential drugs to the discovery of new, druggable targets within specific neuronal subpopulations. Here we summarise recent developments in calcium imaging for pain research, discuss technical challenges and advances, and examine the potential positive impact of this technique in early preclinical phases of the analgesic drug discovery process.
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24
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Cecchetto C, Vassanelli S, Kuhn B. Simultaneous Two-Photon Voltage or Calcium Imaging and Multi-Channel Local Field Potential Recordings in Barrel Cortex of Awake and Anesthetized Mice. Front Neurosci 2021; 15:741279. [PMID: 34867155 PMCID: PMC8632658 DOI: 10.3389/fnins.2021.741279] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 10/19/2021] [Indexed: 01/01/2023] Open
Abstract
Neuronal population activity, both spontaneous and sensory-evoked, generates propagating waves in cortex. However, high spatiotemporal-resolution mapping of these waves is difficult as calcium imaging, the work horse of current imaging, does not reveal subthreshold activity. Here, we present a platform combining voltage or calcium two-photon imaging with multi-channel local field potential (LFP) recordings in different layers of the barrel cortex from anesthetized and awake head-restrained mice. A chronic cranial window with access port allows injecting a viral vector expressing GCaMP6f or the voltage-sensitive dye (VSD) ANNINE-6plus, as well as entering the brain with a multi-channel neural probe. We present both average spontaneous activity and average evoked signals in response to multi-whisker air-puff stimulations. Time domain analysis shows the dependence of the evoked responses on the cortical layer and on the state of the animal, here separated into anesthetized, awake but resting, and running. The simultaneous data acquisition allows to compare the average membrane depolarization measured with ANNINE-6plus with the amplitude and shape of the LFP recordings. The calcium imaging data connects these data sets to the large existing database of this important second messenger. Interestingly, in the calcium imaging data, we found a few cells which showed a decrease in calcium concentration in response to vibrissa stimulation in awake mice. This system offers a multimodal technique to study the spatiotemporal dynamics of neuronal signals through a 3D architecture in vivo. It will provide novel insights on sensory coding, closing the gap between electrical and optical recordings.
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Affiliation(s)
- Claudia Cecchetto
- Department of Biomedical Sciences, Section of Physiology, University of Padua, Padua, Italy.,Optical Neuroimaging Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Stefano Vassanelli
- Department of Biomedical Sciences, Section of Physiology, University of Padua, Padua, Italy.,Padua Neuroscience Center, University of Padua, Padua, Italy
| | - Bernd Kuhn
- Optical Neuroimaging Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
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25
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Ito S, Si Y, Litke AM, Feldheim DA. Nonlinear visuoauditory integration in the mouse superior colliculus. PLoS Comput Biol 2021; 17:e1009181. [PMID: 34723955 PMCID: PMC8584769 DOI: 10.1371/journal.pcbi.1009181] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 11/11/2021] [Accepted: 10/04/2021] [Indexed: 11/21/2022] Open
Abstract
Sensory information from different modalities is processed in parallel, and then integrated in associative brain areas to improve object identification and the interpretation of sensory experiences. The Superior Colliculus (SC) is a midbrain structure that plays a critical role in integrating visual, auditory, and somatosensory input to assess saliency and promote action. Although the response properties of the individual SC neurons to visuoauditory stimuli have been characterized, little is known about the spatial and temporal dynamics of the integration at the population level. Here we recorded the response properties of SC neurons to spatially restricted visual and auditory stimuli using large-scale electrophysiology. We then created a general, population-level model that explains the spatial, temporal, and intensity requirements of stimuli needed for sensory integration. We found that the mouse SC contains topographically organized visual and auditory neurons that exhibit nonlinear multisensory integration. We show that nonlinear integration depends on properties of auditory but not visual stimuli. We also find that a heuristically derived nonlinear modulation function reveals conditions required for sensory integration that are consistent with previously proposed models of sensory integration such as spatial matching and the principle of inverse effectiveness.
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Affiliation(s)
- Shinya Ito
- Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, California, United States of America
- Mindscope program, Allen Institute, Seattle, Washington, United States of America
| | - Yufei Si
- The Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California, United States of America
| | - Alan M. Litke
- Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, California, United States of America
| | - David A. Feldheim
- The Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, California, United States of America
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Markicevic M, Savvateev I, Grimm C, Zerbi V. Emerging imaging methods to study whole-brain function in rodent models. Transl Psychiatry 2021; 11:457. [PMID: 34482367 PMCID: PMC8418612 DOI: 10.1038/s41398-021-01575-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 08/05/2021] [Accepted: 08/23/2021] [Indexed: 02/07/2023] Open
Abstract
In the past decade, the idea that single populations of neurons support cognition and behavior has gradually given way to the realization that connectivity matters and that complex behavior results from interactions between remote yet anatomically connected areas that form specialized networks. In parallel, innovation in brain imaging techniques has led to the availability of a broad set of imaging tools to characterize the functional organization of complex networks. However, each of these tools poses significant technical challenges and faces limitations, which require careful consideration of their underlying anatomical, physiological, and physical specificity. In this review, we focus on emerging methods for measuring spontaneous or evoked activity in the brain. We discuss methods that can measure large-scale brain activity (directly or indirectly) with a relatively high temporal resolution, from milliseconds to seconds. We further focus on methods designed for studying the mammalian brain in preclinical models, specifically in mice and rats. This field has seen a great deal of innovation in recent years, facilitated by concomitant innovation in gene-editing techniques and the possibility of more invasive recordings. This review aims to give an overview of currently available preclinical imaging methods and an outlook on future developments. This information is suitable for educational purposes and for assisting scientists in choosing the appropriate method for their own research question.
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Affiliation(s)
- Marija Markicevic
- Neural Control of Movement Lab, HEST, ETH Zürich, Zürich, Switzerland
- Neuroscience Center Zurich, University and ETH Zürich, Zürich, Switzerland
| | - Iurii Savvateev
- Neural Control of Movement Lab, HEST, ETH Zürich, Zürich, Switzerland
- Neuroscience Center Zurich, University and ETH Zürich, Zürich, Switzerland
- Decision Neuroscience Lab, HEST, ETH Zürich, Zürich, Switzerland
| | - Christina Grimm
- Neural Control of Movement Lab, HEST, ETH Zürich, Zürich, Switzerland
- Neuroscience Center Zurich, University and ETH Zürich, Zürich, Switzerland
| | - Valerio Zerbi
- Neural Control of Movement Lab, HEST, ETH Zürich, Zürich, Switzerland.
- Neuroscience Center Zurich, University and ETH Zürich, Zürich, Switzerland.
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Deciphering the Role of Ion Channels in Early Defense Signaling against Herbivorous Insects. Cells 2021; 10:cells10092219. [PMID: 34571868 PMCID: PMC8470099 DOI: 10.3390/cells10092219] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/16/2021] [Accepted: 08/20/2021] [Indexed: 12/14/2022] Open
Abstract
Plants and insect herbivores are in a relentless battle to outwit each other. Plants have evolved various strategies to detect herbivores and mount an effective defense system against them. These defenses include physical and structural barriers such as spines, trichomes, cuticle, or chemical compounds, including secondary metabolites such as phenolics and terpenes. Plants perceive herbivory by both mechanical and chemical means. Mechanical sensing can occur through the perception of insect biting, piercing, or chewing, while chemical signaling occurs through the perception of various herbivore-derived compounds such as oral secretions (OS) or regurgitant, insect excreta (frass), or oviposition fluids. Interestingly, ion channels or transporters are the first responders for the perception of these mechanical and chemical cues. These transmembrane pore proteins can play an important role in plant defense through the induction of early signaling components such as plasma transmembrane potential (Vm) fluctuation, intracellular calcium (Ca2+), and reactive oxygen species (ROS) generation, followed by defense gene expression, and, ultimately, plant defense responses. In recent years, studies on early plant defense signaling in response to herbivory have been gaining momentum with the application of genetically encoded GFP-based sensors for real-time monitoring of early signaling events and genetic tools to manipulate ion channels involved in plant-herbivore interactions. In this review, we provide an update on recent developments and advances on early signaling events in plant-herbivore interactions, with an emphasis on the role of ion channels in early plant defense signaling.
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Redolfi N, García-Casas P, Fornetto C, Sonda S, Pizzo P, Pendin D. Lighting Up Ca 2+ Dynamics in Animal Models. Cells 2021; 10:2133. [PMID: 34440902 PMCID: PMC8392631 DOI: 10.3390/cells10082133] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/08/2021] [Accepted: 08/16/2021] [Indexed: 12/11/2022] Open
Abstract
Calcium (Ca2+) signaling coordinates are crucial processes in brain physiology. Particularly, fundamental aspects of neuronal function such as synaptic transmission and neuronal plasticity are regulated by Ca2+, and neuronal survival itself relies on Ca2+-dependent cascades. Indeed, impaired Ca2+ homeostasis has been reported in aging as well as in the onset and progression of neurodegeneration. Understanding the physiology of brain function and the key processes leading to its derangement is a core challenge for neuroscience. In this context, Ca2+ imaging represents a powerful tool, effectively fostered by the continuous amelioration of Ca2+ sensors in parallel with the improvement of imaging instrumentation. In this review, we explore the potentiality of the most used animal models employed for Ca2+ imaging, highlighting their application in brain research to explore the pathogenesis of neurodegenerative diseases.
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Affiliation(s)
- Nelly Redolfi
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Paloma García-Casas
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Chiara Fornetto
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Sonia Sonda
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Paola Pizzo
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy
| | - Diana Pendin
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy
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3D holotomographic monitoring of Ca ++ dynamics during ionophore-induced Neospora caninum tachyzoite egress from primary bovine host endothelial cells. Parasitol Res 2021; 121:1169-1177. [PMID: 34386856 PMCID: PMC8986705 DOI: 10.1007/s00436-021-07260-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 07/18/2021] [Indexed: 12/04/2022]
Abstract
Neospora caninum represents an obligate intracellular parasite that belongs to the phylum Apicomplexa and is a major abortive agent in bovines. During merogony, N. caninum tachyzoites invade and proliferate in host cells in vivo, including endothelial cells of lymphatic and blood vessels. The egress at the end of the lytic cycle is tightly regulated in apicomplexans. Evidence in Toxoplasma gondii shows that Ca++ signalling governs tachyzoite egress. Much less is known on egress mechanisms of N. caninum. Here, we show, using 3D live cell holotomographic microscopy in fluo-4 AM-loaded N. caninum-infected BUVEC, that treatments with the calcium ionophore A23187 at 24- and 42-h post-infection (h p. i.) induced a fast and sustained increase in Ca++ signals in parallel to tachyzoite egress. A23187 treatments exclusively triggered tachyzoite release at 42-h p. i. but failed to do so at 24-h p. i. indicating a role for meront maturation in calcium-induced tachyzoite egress. Overall, we show that live cell 3D holotomographic analysis in combination with epifluorescence is a suitable tool to study calcium dynamics related to coccidian egress or other important cell functions.
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Current Review of Optical Neural Interfaces for Clinical Applications. MICROMACHINES 2021; 12:mi12080925. [PMID: 34442547 PMCID: PMC8400671 DOI: 10.3390/mi12080925] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/20/2021] [Accepted: 07/29/2021] [Indexed: 11/16/2022]
Abstract
Neural interfaces, which enable the recording and stimulation of living neurons, have emerged as valuable tools in understanding the brain in health and disease, as well as serving as neural prostheses. While neural interfaces are typically based on electrical transduction, alternative energy modalities have been explored to create safe and effective approaches. Among these approaches, optical methods of linking neurons to the outside world have gained attention because light offers high spatial selectivity and decreased invasiveness. Here, we review the current state-of-art of optical neural interfaces and their clinical applications. Optical neural interfaces can be categorized into optical control and optical readout, each of which can be divided into intrinsic and extrinsic approaches. We discuss the advantages and disadvantages of each of these methods and offer a comparison of relative performance. Future directions, including their clinical opportunities, are discussed with regard to the optical properties of biological tissue.
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Yang L, Zhu X, Finlay DB, Glass M, Duffull SB. Exploring group size for statistical analysis of real-time signalling experiments. Br J Pharmacol 2021; 178:3997-4004. [PMID: 34031869 DOI: 10.1111/bph.15572] [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: 08/27/2020] [Revised: 04/20/2021] [Accepted: 05/07/2021] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND AND PURPOSE Classical pharmacological bioassays generally use observed effects from a concentration series, at a single equilibrium time point to construct a concentration-effect curve, representing one experiment. However, if the full kinetic profile of the effect data for each concentration was evaluated simultaneously, then the analysis would be more powerful. In this work, we explore if more precise parameters can be achieved by using the full kinetic method. EXPERIMENTAL APPROACH We used a simulation estimation study to explore the influence of kinetic analysis on the precision of the Emax model parameter estimates (Emax and C50 ). We compared a full kinetic approach in which all effect versus time data from a theoretical real-time signalling experiment were analysed simultaneously with a 'reference' approach. The theoretical real-time signalling experiment was based on a previously published CB2 receptor-binding experiment. KEY RESULTS The reference method with a group size (n) of 5 provided highly precise parameter estimates (coefficient of variation [CV] 3.4% for Emax and 0.72% for C50 ). A full kinetic method provided more precise estimates than the reference with equal or smaller group sizes. Note that group size 'n' here refers to the number of technical replicates rather than the number of biological replicates. CONCLUSION AND IMPLICATIONS A full kinetic method can yield more precise parameter estimates than the equilibrium method. Such an approach may be more useful for researchers.
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Affiliation(s)
- Liang Yang
- Otago Pharmacometrics Group, School of Pharmacy, University of Otago, Dunedin, New Zealand
| | - Xiao Zhu
- Otago Pharmacometrics Group, School of Pharmacy, University of Otago, Dunedin, New Zealand
| | - David B Finlay
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand
| | - Michelle Glass
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand
| | - Stephen B Duffull
- Otago Pharmacometrics Group, School of Pharmacy, University of Otago, Dunedin, New Zealand
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Jasmin NH, Thin MZ, Johnson RD, Jackson LH, Roberts TA, David AL, Lythgoe MF, Yang PC, Davidson SM, Camelliti P, Stuckey DJ. Myocardial Viability Imaging using Manganese-Enhanced MRI in the First Hours after Myocardial Infarction. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2003987. [PMID: 34105284 PMCID: PMC8188227 DOI: 10.1002/advs.202003987] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 02/08/2021] [Indexed: 05/19/2023]
Abstract
Early measurements of tissue viability after myocardial infarction (MI) are essential for accurate diagnosis and treatment planning but are challenging to obtain. Here, manganese, a calcium analogue and clinically approved magnetic resonance imaging (MRI) contrast agent, is used as an imaging biomarker of myocardial viability in the first hours after experimental MI. Safe Mn2+ dosing is confirmed by measuring in vitro beating rates, calcium transients, and action potentials in cardiomyocytes, and in vivo heart rates and cardiac contractility in mice. Quantitative T1 mapping-manganese-enhanced MRI (MEMRI) reveals elevated and increasing Mn2+ uptake in viable myocardium remote from the infarct, suggesting MEMRI offers a quantitative biomarker of cardiac inotropy. MEMRI evaluation of infarct size at 1 h, 1 and 14 days after MI quantifies myocardial viability earlier than the current gold-standard technique, late-gadolinium-enhanced MRI. These data, coupled with the re-emergence of clinical Mn2+ -based contrast agents open the possibility of using MEMRI for direct evaluation of myocardial viability early after ischemic onset in patients.
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Affiliation(s)
- Nur Hayati Jasmin
- UCL Centre for Advanced Biomedical ImagingDivision of MedicineUniversity College LondonLondonWC1E 6DDUK
- School of Medical ImagingFaculty of Health SciencesUniversiti Sultan Zainal AbidinKuala Terengganu21300Malaysia
| | - May Zaw Thin
- UCL Centre for Advanced Biomedical ImagingDivision of MedicineUniversity College LondonLondonWC1E 6DDUK
| | - Robert D. Johnson
- School of Biosciences and MedicineUniversity of SurreyGuildfordGU2 7XHUK
| | - Laurence H. Jackson
- School of Biomedical Engineering & Imaging SciencesKing's College LondonLondonSE1 7EHUK
| | - Thomas A. Roberts
- School of Biomedical Engineering & Imaging SciencesKing's College LondonLondonSE1 7EHUK
| | - Anna L. David
- UCL Elizabeth Garrett Anderson Institute for Women's HealthLondonWC1E 6BTUK
| | - Mark F. Lythgoe
- UCL Centre for Advanced Biomedical ImagingDivision of MedicineUniversity College LondonLondonWC1E 6DDUK
| | - Philip C. Yang
- Division of Cardiovascular MedicineDepartment of MedicineStanford UniversityStanfordCA94305USA
| | - Sean M. Davidson
- The Hatter Cardiovascular InstituteUniversity College London67 Chenies MewsLondonWC1E 6HXUK
| | - Patrizia Camelliti
- School of Biosciences and MedicineUniversity of SurreyGuildfordGU2 7XHUK
| | - Daniel J. Stuckey
- UCL Centre for Advanced Biomedical ImagingDivision of MedicineUniversity College LondonLondonWC1E 6DDUK
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Yu X, Moye SL, Khakh BS. Local and CNS-Wide Astrocyte Intracellular Calcium Signaling Attenuation In Vivo with CalEx flox Mice. J Neurosci 2021; 41:4556-4574. [PMID: 33903221 PMCID: PMC8260243 DOI: 10.1523/jneurosci.0085-21.2021] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/21/2021] [Accepted: 03/30/2021] [Indexed: 01/12/2023] Open
Abstract
Astrocytes exist throughout the CNS and affect neural circuits and behavior through intracellular Ca2+ signaling. Studying the function(s) of astrocyte Ca2+ signaling has proven difficult because of the paucity of tools to achieve selective attenuation. Based on recent studies, we generated and used male and female knock-in mice for Cre-dependent expression of mCherry-tagged hPMCA2w/b to attenuate astrocyte Ca2+ signaling in genetically defined cells in vivo (CalExflox mice for Calcium Extrusion). We characterized CalExflox mice following local AAV-Cre microinjections into the striatum and found reduced astrocyte Ca2+ signaling (∼90%) accompanied with repetitive self-grooming behavior. We also crossed CalExflox mice to astrocyte-specific Aldh1l1-Cre/ERT2 mice to achieve inducible global CNS-wide Ca2+ signaling attenuation. Within 6 d of induction in the bigenic mice, we observed significantly altered ambulation in the open field, disrupted motor coordination and gait, and premature lethality. Furthermore, with histologic, imaging, and transcriptomic analyses, we identified cellular and molecular alterations in the cerebellum following mCherry-tagged hPMCA2w/b expression. Our data show that expression of mCherry-tagged hPMCA2w/b with CalExflox mice throughout the CNS resulted in substantial attenuation of astrocyte Ca2+ signaling and significant behavioral alterations in adult mice. We interpreted these findings candidly in relation to the ability of CalEx to attenuate astrocyte Ca2+ signaling, with regards to additional mechanistic interpretations of the data, and their relation to past studies that reduced astrocyte Ca2+ signaling throughout the CNS. The data and resources provide complementary ways to interrogate the function(s) of astrocytes in multiple experimental scenarios.SIGNIFICANCE STATEMENT Astrocytes represent a significant fraction of all brain cells and tile the entire central nervous system. Unlike neurons, astrocytes lack propagated electrical signals. Instead, astrocytes are proposed to use diverse and dynamic intracellular Ca2+ signals to communicate with other cells. An open question concerns if and how astrocyte Ca2+ signaling regulates behavior in adult mice. We approached this problem by generating a new transgenic mouse line to achieve inducible astrocyte Ca2+ signaling attenuation in vivo We report our data with this mouse line and we interpret the findings candidly in relation to past studies and within the framework of different mechanistic interpretations.
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Affiliation(s)
- Xinzhu Yu
- Department of Physiology
- Department of Molecular and Integrative Physiology, Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801-3704
| | | | - Baljit S Khakh
- Department of Physiology
- Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90095-1751
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Kazwiny Y, Pedrosa J, Zhang Z, Boesmans W, D'hooge J, Vanden Berghe P. Extracting neuronal activity signals from microscopy recordings of contractile tissue using B-spline Explicit Active Surfaces (BEAS) cell tracking. Sci Rep 2021; 11:10937. [PMID: 34035411 PMCID: PMC8149687 DOI: 10.1038/s41598-021-90448-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 05/06/2021] [Indexed: 01/13/2023] Open
Abstract
Ca2+ imaging is a widely used microscopy technique to simultaneously study cellular activity in multiple cells. The desired information consists of cell-specific time series of pixel intensity values, in which the fluorescence intensity represents cellular activity. For static scenes, cellular signal extraction is straightforward, however multiple analysis challenges are present in recordings of contractile tissues, like those of the enteric nervous system (ENS). This layer of critical neurons, embedded within the muscle layers of the gut wall, shows optical overlap between neighboring neurons, intensity changes due to cell activity, and constant movement. These challenges reduce the applicability of classical segmentation techniques and traditional stack alignment and regions-of-interest (ROIs) selection workflows. Therefore, a signal extraction method capable of dealing with moving cells and is insensitive to large intensity changes in consecutive frames is needed. Here we propose a b-spline active contour method to delineate and track neuronal cell bodies based on local and global energy terms. We develop both a single as well as a double-contour approach. The latter takes advantage of the appearance of GCaMP expressing cells, and tracks the nucleus' boundaries together with the cytoplasmic contour, providing a stable delineation of neighboring, overlapping cells despite movement and intensity changes. The tracked contours can also serve as landmarks to relocate additional and manually-selected ROIs. This improves the total yield of efficacious cell tracking and allows signal extraction from other cell compartments like neuronal processes. Compared to manual delineation and other segmentation methods, the proposed method can track cells during large tissue deformations and high-intensity changes such as during neuronal firing events, while preserving the shape of the extracted Ca2+ signal. The analysis package represents a significant improvement to available Ca2+ imaging analysis workflows for ENS recordings and other systems where movement challenges traditional Ca2+ signal extraction workflows.
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Affiliation(s)
- Youcef Kazwiny
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven (KU Leuven), Leuven, Belgium
| | - João Pedrosa
- Laboratory of Cardiovascular Imaging and Dynamics, Department of Cardiovascular Sciences, University of Leuven (KU Leuven), Leuven, Belgium
- Institute for Systems and Computer Engineering, Technology and Science, INESC TEC, Porto, Portugal
| | - Zhiqing Zhang
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven (KU Leuven), Leuven, Belgium
| | - Werend Boesmans
- Department of Pathology, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, The Netherlands
- Biomedical Research Institute (BIOMED), Hasselt University, Hasselt, Belgium
| | - Jan D'hooge
- Laboratory of Cardiovascular Imaging and Dynamics, Department of Cardiovascular Sciences, University of Leuven (KU Leuven), Leuven, Belgium
| | - Pieter Vanden Berghe
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), University of Leuven (KU Leuven), Leuven, Belgium.
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Hadaeghi F, Diercks BP, Schetelig D, Damicelli F, Wolf IMA, Werner R. Spatio-temporal feature learning with reservoir computing for T-cell segmentation in live-cell [Formula: see text] fluorescence microscopy. Sci Rep 2021; 11:8233. [PMID: 33859269 PMCID: PMC8050068 DOI: 10.1038/s41598-021-87607-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 03/25/2021] [Indexed: 11/09/2022] Open
Abstract
Advances in high-resolution live-cell [Formula: see text] imaging enabled subcellular localization of early [Formula: see text] signaling events in T-cells and paved the way to investigate the interplay between receptors and potential target channels in [Formula: see text] release events. The huge amount of acquired data requires efficient, ideally automated image processing pipelines, with cell localization/segmentation as central tasks. Automated segmentation in live-cell cytosolic [Formula: see text] imaging data is, however, challenging due to temporal image intensity fluctuations, low signal-to-noise ratio, and photo-bleaching. Here, we propose a reservoir computing (RC) framework for efficient and temporally consistent segmentation. Experiments were conducted with Jurkat T-cells and anti-CD3 coated beads used for T-cell activation. We compared the RC performance with a standard U-Net and a convolutional long short-term memory (LSTM) model. The RC-based models (1) perform on par in terms of segmentation accuracy with the deep learning models for cell-only segmentation, but show improved temporal segmentation consistency compared to the U-Net; (2) outperform the U-Net for two-emission wavelengths image segmentation and differentiation of T-cells and beads; and (3) perform on par with the convolutional LSTM for single-emission wavelength T-cell/bead segmentation and differentiation. In turn, RC models contain only a fraction of the parameters of the baseline models and reduce the training time considerably.
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Affiliation(s)
- Fatemeh Hadaeghi
- Department of Computational Neuroscience, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246 Hamburg, Germany
| | - Björn-Philipp Diercks
- Department of Biochemistry and Molecular Cell Biology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246 Hamburg, Germany
| | - Daniel Schetelig
- Department of Computational Neuroscience, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246 Hamburg, Germany
- Center for Biomedical Artificial Intelligence (bAIome), University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246 Hamburg, Germany
| | - Fabrizio Damicelli
- Department of Computational Neuroscience, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246 Hamburg, Germany
| | - Insa M. A. Wolf
- Department of Biochemistry and Molecular Cell Biology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246 Hamburg, Germany
| | - René Werner
- Department of Computational Neuroscience, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246 Hamburg, Germany
- Center for Biomedical Artificial Intelligence (bAIome), University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246 Hamburg, Germany
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Current State-of-the-Art and Unresolved Problems in Using Human Induced Pluripotent Stem Cell-Derived Dopamine Neurons for Parkinson's Disease Drug Development. Int J Mol Sci 2021; 22:ijms22073381. [PMID: 33806103 PMCID: PMC8037675 DOI: 10.3390/ijms22073381] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/15/2021] [Accepted: 03/22/2021] [Indexed: 12/11/2022] Open
Abstract
Human induced pluripotent stem (iPS) cells have the potential to give rise to a new era in Parkinson's disease (PD) research. As a unique source of midbrain dopaminergic (DA) neurons, iPS cells provide unparalleled capabilities for investigating the pathogenesis of PD, the development of novel anti-parkinsonian drugs, and personalized therapy design. Significant progress in developmental biology of midbrain DA neurons laid the foundation for their efficient derivation from iPS cells. The introduction of 3D culture methods to mimic the brain microenvironment further expanded the vast opportunities of iPS cell-based research of the neurodegenerative diseases. However, while the benefits for basic and applied studies provided by iPS cells receive widespread coverage in the current literature, the drawbacks of this model in its current state, and in particular, the aspects of differentiation protocols requiring further refinement are commonly overlooked. This review summarizes the recent data on general and subtype-specific features of midbrain DA neurons and their development. Here, we review the current protocols for derivation of DA neurons from human iPS cells and outline their general weak spots. The associated gaps in the contemporary knowledge are considered and the possible directions for future research that may assist in improving the differentiation conditions and increase the efficiency of using iPS cell-derived neurons for PD drug development are discussed.
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Li ES, Saha MS. Optimizing Calcium Detection Methods in Animal Systems: A Sandbox for Synthetic Biology. Biomolecules 2021; 11:343. [PMID: 33668387 PMCID: PMC7996158 DOI: 10.3390/biom11030343] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/19/2021] [Accepted: 02/21/2021] [Indexed: 12/16/2022] Open
Abstract
Since the 1970s, the emergence and expansion of novel methods for calcium ion (Ca2+) detection have found diverse applications in vitro and in vivo across a series of model animal systems. Matched with advances in fluorescence imaging techniques, the improvements in the functional range and stability of various calcium indicators have significantly enhanced more accurate study of intracellular Ca2+ dynamics and its effects on cell signaling, growth, differentiation, and regulation. Nonetheless, the current limitations broadly presented by organic calcium dyes, genetically encoded calcium indicators, and calcium-responsive nanoparticles suggest a potential path toward more rapid optimization by taking advantage of a synthetic biology approach. This engineering-oriented discipline applies principles of modularity and standardization to redesign and interrogate endogenous biological systems. This review will elucidate how novel synthetic biology technologies constructed for eukaryotic systems can offer a promising toolkit for interfacing with calcium signaling and overcoming barriers in order to accelerate the process of Ca2+ detection optimization.
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Affiliation(s)
| | - Margaret S. Saha
- Department of Biology, College of William and Mary, Williamsburg, VA 23185, USA;
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38
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Nelson AN, Calhoun MS, Thomas AM, Tavares JL, Ferretti DM, Dillon GM, Mandelblat-Cerf Y. Temporal Progression of Excitotoxic Calcium Following Distal Middle Cerebral Artery Occlusion in Freely Moving Mice. Front Cell Neurosci 2021; 14:566789. [PMID: 33424552 DOI: 10.3389/fncel.2020.566789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/26/2020] [Indexed: 11/13/2022] Open
Abstract
Ischemic stroke is recognized as one of the leading causes of adult disability, morbidity, and death worldwide. Following stroke, acute neuronal excitotoxicity can lead to many deleterious consequences, one of which is the dysregulation of intracellular calcium ultimately culminating in cell death. However, to develop neuroprotective treatments that target neuronal excitotoxicity, it is essential to know the therapeutic time window for intervention following an ischemic event. To address this question, the current study aimed to characterize the magnitude and temporal progression of neuronal intracellular calcium observed following distal middle cerebral artery occlusion (dMCAO) in mice. Using the calcium fluorescence indicator, GCaMP, we tracked neuronal population response in freely moving animals immediately following dMCAO in both the core infarct and peri-infarct regions. Our results demonstrate that calcium excitotoxicity following artery occlusion can be generally characterized by two phases: a transient increase in activity that lasts tens of minutes, followed by a long, slow sustained increase in fluorescence signal. The first phase is primarily thought to represent neuronal hyperexcitability, defining our therapeutic window, while the second may represent gradual cell death. Importantly, we show that the level of intracellular calcium following artery occlusion correlated with the infarct size at 24 h demonstrating a direct connection between excitotoxicity and cell death in our stroke model. In addition, we show that administration of the NMDA antagonist MK-801 resulted in both a decrease in calcium signal and a subsequent reduction in the infarct size. Altogether, this study represents the first demonstration in freely moving animals characterizing the temporal progression of toxic calcium signaling following artery occlusion. In addition, these results define a critical time window for neuroprotective therapeutic intervention in mice.
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Zhang S, Wu QR, Liu LL, Zhang HM, Gao JW, Pei ZM. Osmotic stress alters circadian cytosolic Ca 2+ oscillations and OSCA1 is required in circadian gated stress adaptation. PLANT SIGNALING & BEHAVIOR 2020; 15:1836883. [PMID: 33100175 PMCID: PMC7671097 DOI: 10.1080/15592324.2020.1836883] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/08/2020] [Accepted: 10/09/2020] [Indexed: 05/09/2023]
Abstract
The circadian clock is a universal timing system that involved in plant physical responses to abiotic stresses. Moreover, OSCA1 is an osmosensor responsible for [Ca2+]i increases induced by osmotic stress in plants. However, there is little information on osmosensor involved osmotic stress-triggered circadian clock responses. Using an aequorin-based Ca2+ imaging assay, we found the gradient (0 mM, 200 mM, 500 mM) osmotic stress (induced by sorbitol) both altered the primary circadian parameter of WT and osca1 mutant. This means the plant switch to a fast day/night model to avoid energy consumption. In contrast, the period of WT and osca1 mutant became short since the sorbitol concentration increased from 0 mM to 500 mM. As the sorbitol concentration increased, the phase of the WT becomes more extensive compared with osca1 mutant, which means WT is more capable of coping with the environmental change. Moreover, the amplitude of WT also becomes broader than osca1 mutant, especially in high (500 mM) sorbitol concentration, indicate the WT shows more responses in high osmotic stress. In a word, the WT has much more flexibility to cope with the osmotic stress than osca1 mutant. It implies the OSCA1 might be involved in the circadian gated plant adaptation to the environmental osmotic stress, which opens an avenue to study Ca2+ processes with other circadian signaling pathways.
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Affiliation(s)
- Shu Zhang
- College of Life Sciences, Zhejiang University, Hangzhou, China
- Institute of Vegetables and Flowers, Shandong Academy of Agricultural Sciences and Shandong Key Laboratory of Greenhouse Vegetable Biology and Shandong Branch of National Vegetable Improvement Center, Jinan, China
- Center on Plant Environmental Sensing, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Qian-Rong Wu
- Center on Plant Environmental Sensing, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Lu-Lu Liu
- College of Life Sciences, Zhejiang University, Hangzhou, China
- Center on Plant Environmental Sensing, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Hui-Min Zhang
- College of Life Sciences, Shandong Normal University, Jinan, China
| | - Jian-Wei Gao
- Institute of Vegetables and Flowers, Shandong Academy of Agricultural Sciences and Shandong Key Laboratory of Greenhouse Vegetable Biology and Shandong Branch of National Vegetable Improvement Center, Jinan, China
| | - Zhen-Ming Pei
- College of Life Sciences, Zhejiang University, Hangzhou, China
- Center on Plant Environmental Sensing, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
- Department of Biology, Duke University, Durham, NC, USA
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40
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Lavanderos B, Silva I, Cruz P, Orellana-Serradell O, Saldías MP, Cerda O. TRP Channels Regulation of Rho GTPases in Brain Context and Diseases. Front Cell Dev Biol 2020; 8:582975. [PMID: 33240883 PMCID: PMC7683514 DOI: 10.3389/fcell.2020.582975] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 10/05/2020] [Indexed: 12/13/2022] Open
Abstract
Neurological and neuropsychiatric disorders are mediated by several pathophysiological mechanisms, including developmental and degenerative abnormalities caused primarily by disturbances in cell migration, structural plasticity of the synapse, and blood-vessel barrier function. In this context, critical pathways involved in the pathogenesis of these diseases are related to structural, scaffolding, and enzymatic activity-bearing proteins, which participate in Ca2+- and Ras Homologs (Rho) GTPases-mediated signaling. Rho GTPases are GDP/GTP binding proteins that regulate the cytoskeletal structure, cellular protrusion, and migration. These proteins cycle between GTP-bound (active) and GDP-bound (inactive) states due to their intrinsic GTPase activity and their dynamic regulation by GEFs, GAPs, and GDIs. One of the most important upstream inputs that modulate Rho GTPases activity is Ca2+ signaling, positioning ion channels as pivotal molecular entities for Rho GTPases regulation. Multiple non-selective cationic channels belonging to the Transient Receptor Potential (TRP) family participate in cytoskeletal-dependent processes through Ca2+-mediated modulation of Rho GTPases. Moreover, these ion channels have a role in several neuropathological events such as neuronal cell death, brain tumor progression and strokes. Although Rho GTPases-dependent pathways have been extensively studied, how they converge with TRP channels in the development or progression of neuropathologies is poorly understood. Herein, we review recent evidence and insights that link TRP channels activity to downstream Rho GTPase signaling or modulation. Moreover, using the TRIP database, we establish associations between possible mediators of Rho GTPase signaling with TRP ion channels. As such, we propose mechanisms that might explain the TRP-dependent modulation of Rho GTPases as possible pathways participating in the emergence or maintenance of neuropathological conditions.
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Affiliation(s)
- Boris Lavanderos
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago, Chile
| | - Ian Silva
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago, Chile
| | - Pablo Cruz
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago, Chile
| | - Octavio Orellana-Serradell
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago, Chile
| | - María Paz Saldías
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago, Chile
| | - Oscar Cerda
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago, Chile.,The Wound Repair, Treatment and Health (WoRTH) Initiative, Santiago, Chile
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41
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Schwarze T, Sprenger T, Riemer J. 1,2,3‐Triazol‐1,4‐diyl‐Fluoroionophores for Zn 2+, Mg 2+and Ca 2+based on Fluorescence Intensity Enhancements in Water. ChemistrySelect 2020. [DOI: 10.1002/slct.202003695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Thomas Schwarze
- Institut für Chemie, Anorganische Chemie Universität Potsdam Karl-Liebknecht-Str. 24–25 14476 Golm Germany
| | - Tobias Sprenger
- Institut für Chemie, Anorganische Chemie Universität Potsdam Karl-Liebknecht-Str. 24–25 14476 Golm Germany
| | - Janine Riemer
- Institut für Chemie, Anorganische Chemie Universität Potsdam Karl-Liebknecht-Str. 24–25 14476 Golm Germany
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42
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Guille-Collignon M, Lemaître F. Overview and outlook of the strategies devoted to electrofluorescence surveys: Application to single cell secretion analysis. Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2020.116055] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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43
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RedquorinXS Mutants with Enhanced Calcium Sensitivity and Bioluminescence Output Efficiently Report Cellular and Neuronal Network Activities. Int J Mol Sci 2020; 21:ijms21217846. [PMID: 33105848 PMCID: PMC7660078 DOI: 10.3390/ijms21217846] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 10/16/2020] [Accepted: 10/19/2020] [Indexed: 01/14/2023] Open
Abstract
Considerable efforts have been focused on shifting the wavelength of aequorin Ca2+-dependent blue bioluminescence through fusion with fluorescent proteins. This approach has notably yielded the widely used GFP-aequorin (GA) Ca2+ sensor emitting green light, and tdTomato-aequorin (Redquorin), whose bioluminescence is completely shifted to red, but whose Ca2+ sensitivity is low. In the present study, the screening of aequorin mutants generated at twenty-four amino acid positions in and around EF-hand Ca2+-binding domains resulted in the isolation of six aequorin single or double mutants (AequorinXS) in EF2, EF3, and C-terminal tail, which exhibited markedly higher Ca2+ sensitivity than wild-type aequorin in vitro. The corresponding Redquorin mutants all showed higher Ca2+ sensitivity than wild-type Redquorin, and four of them (RedquorinXS) matched the Ca2+ sensitivity of GA in vitro. RedquorinXS mutants exhibited unaltered thermostability and peak emission wavelengths. Upon stable expression in mammalian cell line, all RedquorinXS mutants reported the activation of the P2Y2 receptor by ATP with higher sensitivity and assay robustness than wt-Redquorin, and one, RedquorinXS-Q159T, outperformed GA. Finally, wide-field bioluminescence imaging in mouse neocortical slices showed that RedquorinXS-Q159T and GA similarly reported neuronal network activities elicited by the removal of extracellular Mg2+. Our results indicate that RedquorinXS-Q159T is a red light-emitting Ca2+ sensor suitable for the monitoring of intracellular signaling in a variety of applications in cells and tissues, and is a promising candidate for the transcranial monitoring of brain activities in living mice.
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de Melo Reis RA, Freitas HR, de Mello FG. Cell Calcium Imaging as a Reliable Method to Study Neuron-Glial Circuits. Front Neurosci 2020; 14:569361. [PMID: 33122991 PMCID: PMC7566175 DOI: 10.3389/fnins.2020.569361] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/24/2020] [Indexed: 12/12/2022] Open
Abstract
Complex dynamic cellular networks have been studied in physiological and pathological processes under the light of single-cell calcium imaging (SCCI), a method that correlates functional data based on calcium shifts operated by different intracellular and extracellular mechanisms integrated with their cell phenotypes. From the classic synaptic structure to tripartite astrocytic model or the recent quadripartite microglia added ensemble, as well as other physiological tissues, it is possible to follow how cells signal spatiotemporally to cellular patterns. This methodology has been used broadly due to the universal properties of calcium as a second messenger. In general, at least two types of receptor operate through calcium permeation: a fast-acting ionotropic receptor channel and a slow-activating metabotropic receptor, added to exchangers/transporters/pumps and intracellular Ca2+ release activated by messengers. These prototypes have gained an enormous amount of information in dynamic signaling circuits. SCCI has also been used as a method to associate phenotypic markers during development and stage transitions in progenitors, stem, vascular cells, neuro- and glioblasts, neurons, astrocytes, oligodendrocytes, and microglia that operate through ion channels, transporters, and receptors. Also, cancer cells or inducible cell lines from human organoids characterized by transition stages are currently being used to model diseases or reconfigure healthy cells in terms of the expression of calcium-binding/permeable molecules and shed light on therapy.
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Affiliation(s)
- Ricardo Augusto de Melo Reis
- Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho, CCS, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Hércules Rezende Freitas
- Department of Pathology and Laboratory Medicine, MIND Institute, University of California, Davis, Sacramento, CA, United States
| | - Fernando Garcia de Mello
- Laboratório de Neuroquímica, Instituto de Biofísica Carlos Chagas Filho, CCS, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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45
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Williams PDE, Verma S, Robertson AP, Martin RJ. Adapting techniques for calcium imaging in muscles of adult Brugia malayi. INVERTEBRATE NEUROSCIENCE 2020; 20:12. [PMID: 32803437 DOI: 10.1007/s10158-020-00247-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 08/06/2020] [Indexed: 02/07/2023]
Abstract
Brugia malayi is a human filarial nematode parasite that causes lymphatic filariasis or 'elephantiasis' a disfiguring neglected tropical disease. This parasite is a more tractable nematode parasite for the experimental study of anthelmintic drugs and has been studied with patch-clamp and RNAi techniques. Unlike in C. elegans however, calcium signaling in B. malayi or other nematode parasites has not been achieved, limiting the studies of the mode of action of anthelmintic drugs. We describe here the development of calcium imaging methods that allow us to characterize changes in cellular calcium in the muscles of B. malayi. This is a powerful technique that can help in elucidating the mode of action of selected anthelmintics. We developed two approaches that allow the recording of calcium signals in the muscles of adult B. malayi: (a) soaking the muscles with Fluo-3AM, promoting large-scale imaging of multiple cells simultaneously and, (b) direct insertion of Fluo-3 using microinjection, providing the possibility of performing dual calcium and electrophysiological recordings. Here, we describe the techniques used to optimize dye entry into the muscle cells and demonstrate that detectable increases in Fluo-3 fluorescence to elevated calcium concentrations can be achieved in B. malayi using both techniques.
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Affiliation(s)
- Paul D E Williams
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, 1800 Christensen Dr, Ames, IA, 50011, USA
| | - Saurabh Verma
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, 1800 Christensen Dr, Ames, IA, 50011, USA
| | - Alan P Robertson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, 1800 Christensen Dr, Ames, IA, 50011, USA
| | - Richard J Martin
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, 1800 Christensen Dr, Ames, IA, 50011, USA.
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46
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Ghosh S, Chen Y, George A, Dutta M, Stroscio MA. Fluorescence Resonant Energy Transfer-Based Quantum Dot Sensor for the Detection of Calcium Ions. Front Chem 2020; 8:594. [PMID: 32903607 PMCID: PMC7438717 DOI: 10.3389/fchem.2020.00594] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 06/08/2020] [Indexed: 12/14/2022] Open
Abstract
A simple optical aptasensor has been synthesized for the detection of calcium ions. This sensing approach employs a semiconductor quantum dot (QD)–gold nanoparticle as the donor–quencher pair and operates on the principle of fluorescence resonant energy transfer (FRET). On binding with calcium ions, the DNA aptamer undergoes a conformational change, which changes the distance between the quantum dot and the gold nanoparticle, conjugated on the 5′ terminal and 3′ terminal of the aptamer, respectively. This phenomenon results in the quenching of the quantum dot emission. In this sensor, a maximum quenching of 22.42 ± 0.71% has been achieved at 35 nM calcium ion concentration while the limit of detection has been determined to be 3.77 pM. The sensor has been found to have high specificity for calcium ions in comparison to other metal ions like sodium, magnesium, and potassium. The molecular apta-beacons also demonstrated successful endocytosis and FRET-based calcium ion detection in osteocyte cells when conjugated with a cell-penetrating peptide (DSS).
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Affiliation(s)
- Shreya Ghosh
- Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Yinghua Chen
- Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Anne George
- Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, United States
| | - Mitra Dutta
- Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, IL, United States.,Department of Physics, University of Illinois at Chicago, Chicago, IL, United States
| | - Michael A Stroscio
- Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, IL, United States.,Department of Physics, University of Illinois at Chicago, Chicago, IL, United States.,Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
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TRPV4 promotes acoustic wave-mediated BBB opening via Ca 2+/PKC-δ pathway. J Adv Res 2020; 26:15-28. [PMID: 33133680 PMCID: PMC7584681 DOI: 10.1016/j.jare.2020.06.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 05/14/2020] [Accepted: 06/16/2020] [Indexed: 02/06/2023] Open
Abstract
Introduction Numerous studies have shown the ability of low-energy acoustic waves such as focused ultrasound or shockwave to transiently open blood-brain barrier (BBB) and facilitate drug delivery to the brain. Preclinical and clinical evidences have well demonstrated the efficacy and safety in treating various brain disorders. However, the molecular mechanisms of acoustic waves on the BBB are still not fully understood. Objectives The present study aimed at exploring the possible molecular mechanisms of acoustic wave stimulation on brains. Methods: Briefly describe the experimental design The left hemisphere of the rat‘s brain was treated with pulsed ultrasound from a commercial focused shockwave or a planar ultrasound device, and the right hemisphere served as a control. One hour after the mechanical wave stimulation or overnight, the rats were sacrificed and the brains were harvested for protein or histological analysis. Agonists and antagonists related to the signal transduction pathways of tight junction proteins were used to investigate the possible intracellular mechanisms. Results Intracellular signal transduction analysis shows calcium influx through transient receptor potential vanilloid 4 (TRPV4) channels, and the activation of PKC-δ pathway to mediate dissociation of ZO-1 and occludin after acoustic wave stimulation. The activation of TRPV4 or PKC-δ signaling further increased the expression level of TRPV4, suggesting a feedback loop to regulate BBB permeability. Moreover, the tight junction proteins dissociation can be reversed by administration of PKC-δ inhibitor and TRPV4 antagonist. Conclusion The present study shows the crucial role of TRPV4 in acoustic wave-mediated BBB permeability, specifically its effect on compromising tight junction proteins, ZO-1 and occludin. Our findings provide a new molecular perspective to explain acoustic wave-mediated BBB opening. Moreover, activation of TRPV4 by agonists may reduce the threshold intensity level of acoustic waves for BBB opening, which may prevent undesirable mechanical damages while maintaining efficient BBB opening.
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48
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Qiu L, Wang Y, Qu H. Loading calcium fluorescent probes into protoplasts to detect calcium in the flesh tissue cells of Malus domestica. HORTICULTURE RESEARCH 2020; 7:91. [PMID: 32528703 PMCID: PMC7261807 DOI: 10.1038/s41438-020-0315-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 03/03/2020] [Accepted: 03/20/2020] [Indexed: 05/23/2023]
Abstract
Cytosolic Ca2+ plays a key role in signal transduction in plants. Calcium imaging is the most common approach to studying dynamic changes in the cytoplasmic Ca2+ content. Here, we used mature 'Fuji' apples (Malus pumila Mill.) to obtain viable protoplasts from flesh tissue cells by enzymatic hydrolysis; then, three small-molecule fluorescent probes (fluo-8/AM, fluo-4/AM, and rhod-2/AM) were loaded into the protoplasts. All three Ca2+ fluorescent probes successfully entered the cytoplasm but did not enter the vacuole. Both the Ca2+ chelator (EGTA) and Ca2+ channel blocker (La3+) reduced the fluorescence intensity in the cytoplasm. The calcium ionophore A23187 increased the fluorescence intensity in the cytoplasm at 5 µmol/L but decreased it at 50 µmol/L. Additionally, A23187 reversed the fluorescence intensity in the cytoplasm, which was decreased by La3+. Ionomycin is also a calcium ionophore that can increase the fluorescence intensity of calcium in the cytoplasm. These results suggest that small-molecule Ca2+ fluorescent probes can be used to detect changes in cytosolic calcium levels in the cells of fruit flesh tissue. In addition, the optimum concentration of fluo-8/AM was determined to be 5 µmol/L. This was the first time that protoplasts have been isolated from apple flesh tissue cells and small-molecule fluorescent probes have been used to detect calcium in the cytoplasm of flesh tissue cells. This study provides a new method to study calcium signal transduction in fruit flesh tissue.
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Affiliation(s)
- Lina Qiu
- College of Horticulture, Qingdao Agricultural University, Qingdao City, China
| | - Yongzhang Wang
- College of Horticulture, Qingdao Agricultural University, Qingdao City, China
| | - Haiyong Qu
- College of Horticulture, Qingdao Agricultural University, Qingdao City, China
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49
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Bailly J, Del Rossi N, Runtz L, Li JJ, Park D, Scherrer G, Tanti A, Birling MC, Darcq E, Kieffer BL. Targeting Morphine-Responsive Neurons: Generation of a Knock-In Mouse Line Expressing Cre Recombinase from the Mu-Opioid Receptor Gene Locus. eNeuro 2020; 7:ENEURO.0433-19.2020. [PMID: 32381649 PMCID: PMC7266138 DOI: 10.1523/eneuro.0433-19.2020] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 03/23/2020] [Accepted: 04/09/2020] [Indexed: 12/12/2022] Open
Abstract
The mu-opioid receptor (MOR) modulates nociceptive pathways and reward processing, and mediates the strong analgesic and addictive properties of both medicinal as well as abused opioid drugs. MOR function has been extensively studied, and tools to manipulate or visualize the receptor protein are available. However, circuit mechanisms underlying MOR-mediated effects are less known, because genetic access to MOR-expressing neurons is lacking. Here we report the generation of a knock-in Oprm1-Cre mouse line, which allows targeting and manipulating MOR opioid-responsive neurons. A cDNA encoding a T2A cleavable peptide and Cre recombinase fused to enhanced green fluorescent protein (EGFP/Cre) was inserted downstream of the Oprm1 gene sequence. The resulting Oprm1-Cre line shows intact Oprm1 gene transcription. MOR and EGFP/Cre proteins are coexpressed in the same neurons, and localized in cytoplasmic and nuclear compartments, respectively. MOR signaling is unaltered, demonstrated by maintained DAMGO-induced G-protein activation, and in vivo MOR function is preserved as indicated by normal morphine-induced analgesia, hyperlocomotion, and sensitization. The Cre recombinase efficiently drives the expression of Cre-dependent reporter genes, shown by local virally mediated expression in the medial habenula and brain-wide fluorescence on breeding with tdTomato reporter mice, the latter showing a distribution patterns typical of MOR expression. Finally, we demonstrate that optogenetic activation of MOR neurons in the ventral tegmental area of Oprm1-Cre mice evokes strong avoidance behavior, as anticipated from the literature. The Oprm1-Cre line is therefore an excellent tool for both mapping and functional studies of MOR-positive neurons, and will be of broad interest for opioid, pain, and addiction research.
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Affiliation(s)
- Julie Bailly
- Department of Psychiatry, McGill University, Douglas Hospital Research Centre, Montreal, Quebec H4H 1R3, Canada
| | - Natalie Del Rossi
- Department of Psychiatry, McGill University, Douglas Hospital Research Centre, Montreal, Quebec H4H 1R3, Canada
| | - Léonie Runtz
- Department of Psychiatry, McGill University, Douglas Hospital Research Centre, Montreal, Quebec H4H 1R3, Canada
| | - Jing-Jing Li
- Department of Psychiatry, McGill University, Douglas Hospital Research Centre, Montreal, Quebec H4H 1R3, Canada
| | - DaWoon Park
- Department of Psychiatry, McGill University, Douglas Hospital Research Centre, Montreal, Quebec H4H 1R3, Canada
| | - Grégory Scherrer
- Department of Cell Biology and Physiology, UNC Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Cell Biology and Physiology, UNC Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Arnaud Tanti
- Department of Psychiatry, McGill University, Douglas Hospital Research Centre, Montreal, Quebec H4H 1R3, Canada
| | - Marie-Christine Birling
- CELPHEDIA, PHENOMIN, Institut Clinique de la Souris (ICS), 67404 Illkirch-Graffenstaden, France
| | - Emmanuel Darcq
- Department of Psychiatry, McGill University, Douglas Hospital Research Centre, Montreal, Quebec H4H 1R3, Canada
| | - Brigitte L Kieffer
- Department of Psychiatry, McGill University, Douglas Hospital Research Centre, Montreal, Quebec H4H 1R3, Canada
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50
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Selected DNA aptamers as hydroxyapatite affinity reagents. Anal Chim Acta 2020; 1110:115-121. [PMID: 32278386 DOI: 10.1016/j.aca.2020.03.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 03/12/2020] [Accepted: 03/14/2020] [Indexed: 11/22/2022]
Abstract
DNA aptamers were selected for their ability to bind specifically and quickly to crystalline hydroxyapatite (Ca10(PO4)6(OH)2; HAP), the primary mineral component of enamel and bone. Aptamers were found to have an enhanced percent of G-nucleotides and a propensity for forming a G-quadruplex secondary structure. One aptamer was studied in comparison to control sequences and was found to bind with high affinity and at high loading capacity, with enhanced binding kinetics, and with specificity for crystalline HAP material over amorphous calcium phosphate (ACP) and β-tricalcium phosphate (TCP). The fluorescently-functionalized aptamer was demonstrated to specifically label HAP in a surface binding experiment and suggests the usefulness of this selected aptamer in biomedical or biotechnology fields where the labeling of specific calcium phosphate materials is required.
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