1
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Lin YM, Shi JY, Yang GG. Endoplasmic reticulum targeted fluorescent probe for real-time monitoring the viscosity changes induced by calcium homeostasis disruption. Talanta 2024; 275:126173. [PMID: 38692051 DOI: 10.1016/j.talanta.2024.126173] [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: 01/09/2024] [Revised: 04/19/2024] [Accepted: 04/25/2024] [Indexed: 05/03/2024]
Abstract
The endoplasmic reticulum (ER) acts as the major storage site for calcium ions, which are messenger ions for intracellular signaling. Disruption of calcium ion homeostasis can significantly affect the viscosity, polarity and pH of the ER. However, it is still unclear the relationship between the viscosity changes in ER and the imbalance of calcium ion homeostasis. Herein, we developed a novel fluorescent probe, named TPA, for monitoring viscosity changes that specifically targets the endoplasmic reticulum rather than mitochondria or lysosomes. TPA probe displayed good stability, as well as high responsiveness and selectivity to viscosity. The fluorescence intensity of TPA was significantly enhanced with the increased concentration or incubation time of the stimulating agents(i.e., tunicamycin), showing high responsiveness to the viscosity changes in ER. Furthermore, the TPA probe successfully demonstrated that an increase in intracellular calcium ion concentration leads to an increase in ER viscosity, whereas a decrease in calcium ion concentration leads to a decrease viscosity in ER. Both in vitro and in vivo experiments demonstrated that TPA probe successfully detected the viscosity changes in ER, especially the effects of calcium ion homeostasis disruption on ER. Overall, the TPA probe represents an efficient method for studying the relationship between calcium ion homeostasis and ER viscosity.
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Affiliation(s)
- Ya Meng Lin
- Biochemical Engineering Research Center, Anhui University of Technology, Ma'anshan, Anhui, 243002, PR China; School of Chemistry and Chemical Engineering, Anhui University of Technology, Ma'anshan, Anhui, 243002, PR China
| | - Jia Yi Shi
- Biochemical Engineering Research Center, Anhui University of Technology, Ma'anshan, Anhui, 243002, PR China; School of Chemistry and Chemical Engineering, Anhui University of Technology, Ma'anshan, Anhui, 243002, PR China
| | - Gang-Gang Yang
- Biochemical Engineering Research Center, Anhui University of Technology, Ma'anshan, Anhui, 243002, PR China; School of Chemistry and Chemical Engineering, Anhui University of Technology, Ma'anshan, Anhui, 243002, PR China.
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2
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Parkkinen I, Their A, Asghar MY, Sree S, Jokitalo E, Airavaara M. Pharmacological Regulation of Endoplasmic Reticulum Structure and Calcium Dynamics: Importance for Neurodegenerative Diseases. Pharmacol Rev 2023; 75:959-978. [PMID: 37127349 DOI: 10.1124/pharmrev.122.000701] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 03/27/2023] [Accepted: 04/04/2023] [Indexed: 05/03/2023] Open
Abstract
The endoplasmic reticulum (ER) is the largest organelle of the cell, composed of a continuous network of sheets and tubules, and is involved in protein, calcium (Ca2+), and lipid homeostasis. In neurons, the ER extends throughout the cell, both somal and axodendritic compartments, and is highly important for neuronal functions. A third of the proteome of a cell, secreted and membrane-bound proteins, are processed within the ER lumen and most of these proteins are vital for neuronal activity. The brain itself is high in lipid content, and many structural lipids are produced, in part, by the ER. Cholesterol and steroid synthesis are strictly regulated in the ER of the blood-brain barrier protected brain cells. The high Ca2+ level in the ER lumen and low cytosolic concentration is needed for Ca2+-based intracellular signaling, for synaptic signaling and Ca2+ waves, and for preparing proteins for correct folding in the presence of high Ca2+ concentrations to cope with the high concentrations of extracellular milieu. Particularly, ER Ca2+ is controlled in axodendritic areas for proper neurito- and synaptogenesis and synaptic plasticity and remodeling. In this review, we cover the physiologic functions of the neuronal ER and discuss it in context of common neurodegenerative diseases, focusing on pharmacological regulation of ER Ca2+ Furthermore, we postulate that heterogeneity of the ER, its protein folding capacity, and ensuring Ca2+ regulation are crucial factors for the aging and selective vulnerability of neurons in various neurodegenerative diseases. SIGNIFICANCE STATEMENT: Endoplasmic reticulum (ER) Ca2+ regulators are promising therapeutic targets for degenerative diseases for which efficacious drug therapies do not exist. The use of pharmacological probes targeting maintenance and restoration of ER Ca2+ can provide restoration of protein homeostasis (e.g., folding of complex plasma membrane signaling receptors) and slow down the degeneration process of neurons.
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Affiliation(s)
- Ilmari Parkkinen
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Anna Their
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Muhammad Yasir Asghar
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Sreesha Sree
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Eija Jokitalo
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
| | - Mikko Airavaara
- Neuroscience Center (I.P., A.T., M.A.), Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy (I.P., M.A.), Cell and Tissue Dynamics Research Program, Institute of Biotechnology, Helsinki Institute of Life Sciences (M.Y.A., S.S., E.J.), and Electron Microscopy Unit, Institute of Biotechnology, Helsinki Institute of Life Sciences (E.J.), University of Helsinki, Helsinki, Finland
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3
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Streiff ME, Corbin AC, Ahmad AA, Hunter C, Sachse FB. TRPC1 channels underlie stretch-modulated sarcoplasmic reticulum calcium leak in cardiomyocytes. Front Physiol 2022; 13:1056657. [PMID: 36620209 PMCID: PMC9817106 DOI: 10.3389/fphys.2022.1056657] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 12/12/2022] [Indexed: 12/25/2022] Open
Abstract
Transient receptor potential canonical 1 (TRPC1) channels are Ca2+-permeable ion channels expressed in cardiomyocytes. An involvement of TRPC1 channels in cardiac diseases is widely established. However, the physiological role of TRPC1 channels and the mechanisms through which they contribute to disease development are still under investigation. Our prior work suggested that TRPC1 forms Ca2+ leak channels located in the sarcoplasmic reticulum (SR) membrane. Prior studies suggested that TRPC1 channels in the cell membrane are mechanosensitive, but this was not yet investigated in cardiomyocytes or for SR localized TRPC1 channels. We applied adenoviral transfection to overexpress or suppress TRPC1 expression in neonatal rat ventricular myocytes (NRVMs). Transfections were evaluated with RT-qPCR, western blot, and fluorescent imaging. Single-molecule localization microscopy revealed high colocalization of exogenously expressed TRPC1 and the sarco/endoplasmic reticulum Ca2+ ATPase (SERCA2). To test our hypothesis that TRPC1 channels contribute to mechanosensitive Ca2+ SR leak, we directly measured SR Ca2+ concentration ([Ca2+]SR) using adenoviral transfection with a novel ratiometric genetically encoded SR-targeting Ca2+ sensor. We performed fluorescence imaging to quantitatively assess [Ca2+]SR and leak through TRPC1 channels of NRVMs cultured on stretchable silicone membranes. [Ca2+]SR was increased in cells with suppressed TRPC1 expression vs. control and Transient receptor potential canonical 1-overexpressing cells. We also detected a significant reduction in [Ca2+]SR in cells with Transient receptor potential canonical 1 overexpression when 10% uniaxial stretch was applied. These findings indicate that TRPC1 channels underlie the mechanosensitive modulation of [Ca2+]SR. Our findings are critical for understanding the physiological role of TRPC1 channels and support the development of pharmacological therapies for cardiac diseases.
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Affiliation(s)
- Molly E. Streiff
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, United States,Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Andrea C. Corbin
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, United States,Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Azmi A. Ahmad
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, United States,Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States
| | - Chris Hunter
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, United States
| | - Frank B. Sachse
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, United States,Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States,*Correspondence: Frank B. Sachse,
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4
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Zajac M, Modi S, Krishnan Y. The evolution of organellar calcium mapping technologies. Cell Calcium 2022; 108:102658. [PMID: 36274564 PMCID: PMC10224794 DOI: 10.1016/j.ceca.2022.102658] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/05/2022] [Accepted: 10/08/2022] [Indexed: 01/25/2023]
Abstract
Intracellular Ca2+ fluxes are dynamically controlled by the co-involvement of multiple organellar pools of stored Ca2+. Endolysosomes are emerging as physiologically critical, yet underexplored, sources and sinks of intracellular Ca2+. Delineating the role of organelles in Ca2+ signaling has relied on chemical fluorescent probes and electrophysiological strategies. However, the acidic endolysosomal environment presents unique issues, which preclude the use of traditional chemical reporter strategies to map lumenal Ca2+. Here, we broadly address the current state of knowledge about organellar Ca2+ pools. We then outline the application of traditional probes, and their sensing paradigms. We then discuss how a new generation of probes overcomes the limitations of traditional Ca2+probes, emphasizing their ability to offer critical insights into endolysosomal Ca2+, and its feedback with other organellar pools.
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Affiliation(s)
- Matthew Zajac
- Department of Chemistry, The University of Chicago, Chicago, Illinois, 60637, USA; Neuroscience Institute, The University of Chicago, Chicago, IL, 60637, USA
| | - Souvik Modi
- Esya Labs, Translation and Innovation Hub, Imperial College White City Campus, 84 Wood Lane, London, W12 0BZ, UK
| | - Yamuna Krishnan
- Department of Chemistry, The University of Chicago, Chicago, Illinois, 60637, USA; Neuroscience Institute, The University of Chicago, Chicago, IL, 60637, USA; Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois, 60637, USA.
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5
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Kleist TJ, Wudick MM. Shaping up: Recent advances in the study of plant calcium channels. Curr Opin Cell Biol 2022; 76:102080. [DOI: 10.1016/j.ceb.2022.102080] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/02/2022] [Accepted: 03/13/2022] [Indexed: 12/20/2022]
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6
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Cholesterylation of Smoothened is a calcium-accelerated autoreaction involving an intramolecular ester intermediate. Cell Res 2022; 32:288-301. [PMID: 35121857 PMCID: PMC8888579 DOI: 10.1038/s41422-022-00622-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 01/10/2022] [Indexed: 12/16/2022] Open
Abstract
Hedgehog (Hh) is a morphogen that binds to its receptor Patched 1 and activates Smoothened (SMO), thereby governing embryonic development and postnatal tissue homeostasis. Cholesterol can bind and covalently conjugate to the luminal cysteine-rich domain (CRD) of human SMO at the D95 residue (D99 in mouse). The reaction mechanism and biological function of SMO cholesterylation have not been elucidated. Here, we show that the SMO-CRD undergoes auto-cholesterylation which is boosted by calcium and involves an intramolecular ester intermediate. In cells, Hh stimulation elevates local calcium concentration in the SMO-localized endosomes through store-operated calcium entry. In addition, we identify the signaling-incompetent SMO D95E mutation, and the D95E mutant SMO can bind cholesterol but cannot be modified or activated by cholesterol. The homozygous SmoD99E/D99E knockin mice are embryonic lethal with severe developmental delay, demonstrating that cholesterylation of CRD is required for full-length SMO activation. Our work reveals the unique autocatalytic mechanism of SMO cholesterylation and an unprecedented role of calcium in Hh signaling.
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7
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Burgstaller S, Bischof H, Matt L, Lukowski R. Assessing K + ions and K + channel functions in cancer cell metabolism using fluorescent biosensors. Free Radic Biol Med 2022; 181:43-51. [PMID: 35091062 DOI: 10.1016/j.freeradbiomed.2022.01.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 01/15/2022] [Accepted: 01/24/2022] [Indexed: 12/17/2022]
Abstract
Cancer represents a leading cause of death worldwide. Hence, a better understanding of the molecular mechanisms causing and propelling the disease is of utmost importance. Several cancer entities are associated with altered K+ channel expression which is frequently decisive for malignancy and disease outcome. The impact of such oncogenic K+ channels on cell patho-/physiology and homeostasis and their roles in different subcellular compartments is, however, far from being understood. A refined method to simultaneously investigate metabolic and ionic signaling events on the level of individual cells and their organelles represent genetically encoded fluorescent biosensors, that allow a high-resolution investigation of compartmentalized metabolite or ion dynamics in a non-invasive manner. This feature of these probes makes them versatile tools to visualize and understand subcellular consequences of aberrant K+ channel expression and activity in K+ channel related cancer research.
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Affiliation(s)
- Sandra Burgstaller
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Germany; NMI Natural and Medical Sciences Institute at the University of Tübingen, Reutlingen, 72770, Germany.
| | - Helmut Bischof
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Germany
| | - Lucas Matt
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Germany
| | - Robert Lukowski
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Germany.
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8
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Reddish FN, Miller CL, Deng X, Dong B, Patel AA, Ghane MA, Mosca B, McBean C, Wu S, Solntsev KM, Zhuo Y, Gadda G, Fang N, Cox DN, Mabb AM, Treves S, Zorzato F, Yang JJ. Rapid subcellular calcium responses and dynamics by calcium sensor G-CatchER . iScience 2021; 24:102129. [PMID: 33665552 PMCID: PMC7900224 DOI: 10.1016/j.isci.2021.102129] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 12/14/2020] [Accepted: 01/26/2021] [Indexed: 12/15/2022] Open
Abstract
The precise spatiotemporal characteristics of subcellular calcium (Ca2+) transients are critical for the physiological processes. Here we report a green Ca2+ sensor called "G-CatchER+" using a protein design to report rapid local ER Ca2+ dynamics with significantly improved folding properties. G-CatchER+ exhibits a superior Ca2+ on rate to G-CEPIA1er and has a Ca2+-induced fluorescence lifetimes increase. G-CatchER+ also reports agonist/antagonist triggered Ca2+ dynamics in several cell types including primary neurons that are orchestrated by IP3Rs, RyRs, and SERCAs with an ability to differentiate expression. Upon localization to the lumen of the RyR channel (G-CatchER+-JP45), we report a rapid local Ca2+ release that is likely due to calsequestrin. Transgenic expression of G-CatchER+ in Drosophila muscle demonstrates its utility as an in vivo reporter of stimulus-evoked SR local Ca2+ dynamics. G-CatchER+ will be an invaluable tool to examine local ER/SR Ca2+ dynamics and facilitate drug development associated with ER dysfunction.
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Affiliation(s)
- Florence N Reddish
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Cassandra L Miller
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Xiaonan Deng
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Bin Dong
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Atit A Patel
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA.,Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30303, USA
| | - Mohammad A Ghane
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA.,Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30303, USA
| | - Barbara Mosca
- Department of Life Sciences, General Pathology, University of Ferrara, Ferrara, Italy
| | - Cheyenne McBean
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Shengnan Wu
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA 30303, USA
| | - Kyril M Solntsev
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - You Zhuo
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Giovanni Gadda
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Ning Fang
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
| | - Daniel N Cox
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA.,Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30303, USA
| | - Angela M Mabb
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA.,Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30303, USA
| | - Susan Treves
- Department of Life Sciences, General Pathology, University of Ferrara, Ferrara, Italy.,Department of Biomedicine, Basel University, Hebelstrasse 20, 4031 Basel, Switzerland
| | - Francesco Zorzato
- Department of Life Sciences, General Pathology, University of Ferrara, Ferrara, Italy.,Department of Biomedicine, Basel University, Hebelstrasse 20, 4031 Basel, Switzerland
| | - Jenny J Yang
- Department of Chemistry, Center for Diagnostics and Therapeutics, Advanced Translational Imaging Facility, Georgia State University, Atlanta, GA 30303, USA
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9
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Weigand C, Kim SH, Brown E, Medina E, Mares M, Miller G, Harper JF, Choi WG. A Ratiometric Calcium Reporter CGf Reveals Calcium Dynamics Both in the Single Cell and Whole Plant Levels Under Heat Stress. FRONTIERS IN PLANT SCIENCE 2021; 12:777975. [PMID: 34975960 PMCID: PMC8718611 DOI: 10.3389/fpls.2021.777975] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 11/17/2021] [Indexed: 05/02/2023]
Abstract
Land plants evolved to quickly sense and adapt to temperature changes, such as hot days and cold nights. Given that calcium (Ca2+) signaling networks are implicated in most abiotic stress responses, heat-triggered changes in cytosolic Ca2+ were investigated in Arabidopsis leaves and pollen. Plants were engineered with a reporter called CGf, a ratiometric, genetically encoded Ca2+ reporter with an mCherry reference domain fused to an intensiometric Ca2+ reporter GCaMP6f. Relative changes in [Ca2+]cyt were estimated based on CGf's apparent K D around 220 nM. The ratiometric output provided an opportunity to compare Ca2+ dynamics between different tissues, cell types, or subcellular locations. In leaves, CGf detected heat-triggered cytosolic Ca2+ signals, comprised of three different signatures showing similarly rapid rates of Ca2+ influx followed by differing rates of efflux (50% durations ranging from 5 to 19 min). These heat-triggered Ca2+ signals were approximately 1.5-fold greater in magnitude than blue light-triggered signals in the same leaves. In contrast, growing pollen tubes showed two different heat-triggered responses. Exposure to heat caused tip-focused steady growth [Ca2+]cyt oscillations to shift to a pattern characteristic of a growth arrest (22%), or an almost undetectable [Ca2+]cyt (78%). Together, these contrasting examples of heat-triggered Ca2+ responses in leaves and pollen highlight the diversity of Ca2+ signals in plants, inviting speculations about their differing kinetic features and biological functions.
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Affiliation(s)
- Chrystle Weigand
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Su-Hwa Kim
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Elizabeth Brown
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Emily Medina
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Moises Mares
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
| | - Gad Miller
- The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat-Gan, Israel
| | - Jeffrey F. Harper
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
- *Correspondence: Jeffrey F. Harper,
| | - Won-Gyu Choi
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Reno, NV, United States
- Won-Gyu Choi,
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10
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Pal A, Tian L. Imaging voltage and brain chemistry with genetically encoded sensors and modulators. Curr Opin Chem Biol 2020; 57:166-176. [PMID: 32823064 DOI: 10.1016/j.cbpa.2020.07.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 01/21/2023]
Abstract
Neurons and glia are functionally organized into circuits and higher-order structures that allow the precise information processing required for complex behaviors. To better understand the structure and function of the brain, we must understand synaptic connectivity, action potential generation and propagation, as well as well-orchestrated molecular signaling. Recently, dramatically improved sensors for voltage, intracellular calcium, and neurotransmitters/modulators, combined with advanced microscopy provide new opportunities for in vivo dissection of cellular and circuit activity in awake, behaving animals. This review focuses on the current trends in genetically encoded sensors for molecules and cellular events and their potential applicability to the study of nervous system in health and disease.
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Affiliation(s)
- Akash Pal
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA, USA
| | - Lin Tian
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Davis, CA, USA.
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11
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Bonifacius A, Goldmann O, Floess S, Holtfreter S, Robert PA, Nordengrün M, Kruse F, Lochner M, Falk CS, Schmitz I, Bröker BM, Medina E, Huehn J. Staphylococcus aureus Alpha-Toxin Limits Type 1 While Fostering Type 3 Immune Responses. Front Immunol 2020; 11:1579. [PMID: 32849537 PMCID: PMC7427519 DOI: 10.3389/fimmu.2020.01579] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 06/15/2020] [Indexed: 12/21/2022] Open
Abstract
Staphylococcus aureus can cause life-threatening diseases, and hospital- as well as community-associated antibiotic-resistant strains are an emerging global public health problem. Therefore, prophylactic vaccines or immune-based therapies are considered as alternative treatment opportunities. To develop such novel treatment approaches, a better understanding of the bacterial virulence and immune evasion mechanisms and their potential effects on immune-based therapies is essential. One important staphylococcal virulence factor is alpha-toxin, which is able to disrupt the epithelial barrier in order to establish infection. In addition, alpha-toxin has been reported to modulate other cell types including immune cells. Since CD4+ T cell-mediated immunity is required for protection against S. aureus infection, we were interested in the ability of alpha-toxin to directly modulate CD4+ T cells. To address this, murine naïve CD4+ T cells were differentiated in vitro into effector T cell subsets in the presence of alpha-toxin. Interestingly, alpha-toxin induced death of Th1-polarized cells, while cells polarized under Th17 conditions showed a high resistance toward increasing concentrations of this toxin. These effects could neither be explained by differential expression of the cellular alpha-toxin receptor ADAM10 nor by differential activation of caspases, but might result from an increased susceptibility of Th1 cells toward Ca2+-mediated activation-induced cell death. In accordance with the in vitro findings, an alpha-toxin-dependent decrease of Th1 and concomitant increase of Th17 cells was observed in vivo during S. aureus bacteremia. Interestingly, corresponding subsets of innate lymphoid cells and γδ T cells were similarly affected, suggesting a more general effect of alpha-toxin on the modulation of type 1 and type 3 immune responses. In conclusion, we have identified a novel alpha-toxin-dependent immunomodulatory strategy of S. aureus, which can directly act on CD4+ T cells and might be exploited for the development of novel immune-based therapeutic approaches to treat infections with antibiotic-resistant S. aureus strains.
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Affiliation(s)
- Agnes Bonifacius
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Oliver Goldmann
- Department Infection Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Stefan Floess
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Silva Holtfreter
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Philippe A Robert
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Department Systems Immunology and Braunschweig Integrated Centre of Systems Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Maria Nordengrün
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Friederike Kruse
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Matthias Lochner
- Institute of Infection Immunology, TWINCORE, Centre for Experimental and Clinical Infection Research; A Joint Venture Between the Medical School Hannover and the Helmholtz Centre for Infection Research, Hanover, Germany.,Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hanover, Germany
| | - Christine S Falk
- Institute of Transplant Immunology, Hannover Medical School, Hanover, Germany.,DZIF, German Center for Infectious Diseases, TTU-IICH Hannover-Braunschweig Site, Hanover, Germany
| | - Ingo Schmitz
- Department Systems-Oriented Immunology and Inflammation Research, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Institute for Molecular and Clinical Immunology, Medical Faculty, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.,Department of Molecular Immunology, Ruhr-University Bochum, Bochum, Germany
| | - Barbara M Bröker
- Department of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Eva Medina
- Department Infection Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Jochen Huehn
- Department Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
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12
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Zhang Y, Wang J, Xing S, Li L, Zhao S, Zhu W, Liang K, Liu Y, Chen L. Mitochondria determine the sequential propagation of the calcium macrodomains revealed by the super-resolution calcium lantern imaging. SCIENCE CHINA-LIFE SCIENCES 2020; 63:1543-1551. [PMID: 32279282 DOI: 10.1007/s11427-019-1659-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 02/27/2020] [Indexed: 01/02/2023]
Abstract
Despite the wide application of super-resolution (SR) microscopy in biological studies of cells, the technology is rarely used to monitor functional changes in live cells. By combining fast spinning disc-confocal structured illumination microscopy (SD-SIM) with loading of cytosolic fluorescent Ca2+ indicators, we have developed an SR method for visualization of regional Ca2+ dynamics and related cellular organelle morphology and dynamics, termed SR calcium lantern imaging. In COS-7 cells stimulated with ATP, we have identified various calcium macrodomains characterized by different types of Ca2+ release from endoplasmic reticulum (ER) stores. Finally, we demonstrated various roles of mitochondria in mediating calcium signals from different sources; while mitochondria can globally potentiate the Ca2+ entry associated with store release, mitochondria also locally control Ca2+ release from the neighboring ER stores and assist in their refilling processes.
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Affiliation(s)
- Yulin Zhang
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, 100871, China
| | - Jianyong Wang
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, 100871, China
| | - Shijia Xing
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, 100871, China
| | - Liuju Li
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, 100871, China
| | - Shiqun Zhao
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, 100871, China
| | - Wenzhen Zhu
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, 100871, China
| | - Kuo Liang
- Department of General Surgery, Xuanwu Hospital, Capital Medical University, Beijing, 100053, China
| | - Yanmei Liu
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, 100871, China.,Institute for Brain Research and Rehabilitation (IBRR), Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou, 200062, China
| | - Liangyi Chen
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, 100871, China. .,PKU-IDG/McGovern Institute for Brain Research, Beijing, 100871, China.
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13
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Yuan L, Liu Q, Wang Z, Hou J, Xu P. EI24 tethers endoplasmic reticulum and mitochondria to regulate autophagy flux. Cell Mol Life Sci 2020; 77:1591-1606. [PMID: 31332481 PMCID: PMC11104867 DOI: 10.1007/s00018-019-03236-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 07/16/2019] [Accepted: 07/18/2019] [Indexed: 02/07/2023]
Abstract
Etoposide-induced protein 2.4 (EI24), located on the endoplasmic reticulum (ER) membrane, has been proposed to be an essential autophagy protein. Specific ablation of EI24 in neuronal and liver tissues causes deficiency of autophagy flux. However, the molecular mechanism of the EI24-mediated autophagy process is still poorly understood. Like neurons and hepatic cells, pancreatic β cells are also secretory cells. Pancreatic β cells contain large amounts of ER and continuously synthesize and secrete insulin to maintain blood glucose homeostasis. Yet, the effect of EI24 on autophagy of pancreatic β cells has not been reported. Here, we show that the autophagy process is inhibited in EI24-deficient primary pancreatic β cells. Further mechanistic studies demonstrate that EI24 is enriched at the ER-mitochondria interface and that the C-terminal domain of EI24 is important for the integrity of the mitochondria-associated membrane (MAM) and autophagy flux. Overexpression of EI24, but not the EI24-ΔC mutant, can rescue MAM integrity and decrease the aggregation of p62 and LC3II in the EI24-deficient group. By mass spectrometry-based proteomics following immunoprecipitation, EI24 was found to interact with voltage-dependent anion channel 1 (VDAC1), inositol 1,4,5-trisphosphate receptor (IP3R), and the outer mitochondrial membrane chaperone GRP75. Knockout of EI24 impairs the interaction of IP3R with VDAC1, indicating that these proteins may form a quaternary complex to regulate MAM integrity and the autophagy process.
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Affiliation(s)
- Lin Yuan
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Qi Liu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhe Wang
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Junjie Hou
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Pingyong Xu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100101, China.
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
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