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Giamogante F, Barazzuol L, Maiorca F, Poggio E, Esposito A, Masato A, Napolitano G, Vagnoni A, Calì T, Brini M. A SPLICS reporter reveals [Formula: see text]-synuclein regulation of lysosome-mitochondria contacts which affects TFEB nuclear translocation. Nat Commun 2024; 15:1516. [PMID: 38374070 PMCID: PMC10876553 DOI: 10.1038/s41467-024-46007-2] [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: 06/19/2023] [Accepted: 02/07/2024] [Indexed: 02/21/2024] Open
Abstract
Mitochondrial and lysosomal activities are crucial to maintain cellular homeostasis: optimal coordination is achieved at their membrane contact sites where distinct protein machineries regulate organelle network dynamics, ions and metabolites exchange. Here we describe a genetically encoded SPLICS reporter for short- and long- juxtapositions between mitochondria and lysosomes. We report the existence of narrow and wide lysosome-mitochondria contacts differently modulated by mitophagy, autophagy and genetic manipulation of tethering factors. The overexpression of α-synuclein (α-syn) reduces the apposition of mitochondria/lysosomes membranes and affects their privileged Ca2+ transfer, impinging on TFEB nuclear translocation. We observe enhanced TFEB nuclear translocation in α-syn-overexpressing cells. We propose that α-syn, by interfering with mitochondria/lysosomes tethering impacts on local Ca2+ regulated pathways, among which TFEB mediated signaling, and in turn mitochondrial and lysosomal function. Defects in mitochondria and lysosome represent a common hallmark of neurodegenerative diseases: targeting their communication could open therapeutic avenues.
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Affiliation(s)
- Flavia Giamogante
- Department of Biomedical Sciences (DSB), University of Padova, Padova, Italy
| | - Lucia Barazzuol
- Department of Biomedical Sciences (DSB), University of Padova, Padova, Italy
| | | | - Elena Poggio
- Department of Biology (DIBIO), University of Padova, Padova, Italy
| | - Alessandra Esposito
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
- Department of Medical and Translational Science, Federico II University, Naples, Italy
| | - Anna Masato
- Department of Biology (DIBIO), University of Padova, Padova, Italy
- UK-Dementia Research Institute at UCL, University College London, London, UK
| | - Gennaro Napolitano
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy
- Department of Medical and Translational Science, Federico II University, Naples, Italy
| | - Alessio Vagnoni
- Department of Basic and Clinical Neurosciences, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Tito Calì
- Department of Biomedical Sciences (DSB), University of Padova, Padova, Italy.
- Padova Neuroscience Center (PNC), University of Padova, Padova, Italy.
- Study Center for Neurodegeneration (CESNE), University of Padova, Padova, Italy.
| | - Marisa Brini
- Department of Biology (DIBIO), University of Padova, Padova, Italy.
- Study Center for Neurodegeneration (CESNE), University of Padova, Padova, Italy.
- Department of Pharmaceutical and Pharmacological Sciences (DSF), University of Padova, Padova, Italy.
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2
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Binci F, Offer E, Crosino A, Sciascia I, Kleine-Vehn J, Genre A, Giovannetti M, Navazio L. Spatially and temporally distinct Ca2+ changes in Lotus japonicus roots orient fungal-triggered signalling pathways towards symbiosis or immunity. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:605-619. [PMID: 37712520 DOI: 10.1093/jxb/erad360] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/13/2023] [Indexed: 09/16/2023]
Abstract
Plants activate an immune or symbiotic response depending on the detection of distinct signals from root-interacting microbes. Both signalling cascades involve Ca2+ as a central mediator of early signal transduction. In this study, we combined aequorin- and cameleon-based methods to dissect the changes in cytosolic and nuclear Ca2+ concentration caused by different chitin-derived fungal elicitors in Lotus japonicus roots. Our quantitative analyses highlighted the dual character of the evoked Ca2+ responses taking advantage of the comparison between different genetic backgrounds: an initial Ca2+ influx, dependent on the LysM receptor CERK6 and independent of the common symbiotic signalling pathway (CSSP), is followed by a second CSSP-dependent and CERK6-independent phase, that corresponds to the well-known perinuclear/nuclear Ca2+ spiking. We show that the expression of immunity marker genes correlates with the amplitude of the first Ca2+ change, depends on elicitor concentration, and is controlled by Ca2+ storage in the vacuole. Our findings provide an insight into the Ca2+-mediated signalling mechanisms discriminating plant immunity- and symbiosis-related pathways in the context of their simultaneous activation by single fungal elicitors.
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Affiliation(s)
- Filippo Binci
- Department of Biology, University of Padova, 35131 Padova, Italy
| | - Elisabetta Offer
- Department of Biology, University of Padova, 35131 Padova, Italy
| | - Andrea Crosino
- Department of Life Sciences and Systems Biology, University of Torino, 10125 Torino, Italy
| | - Ivan Sciascia
- Department of Life Sciences and Systems Biology, University of Torino, 10125 Torino, Italy
| | - Jürgen Kleine-Vehn
- Centre for Integrative Biological Signalling Studies (CIBSS), University of Freiburg, 79104 Freiburg, Germany
- Institute of Biology II, Department of Molecular Plant Physiology (MoPP), University of Freiburg, 79104 Freiburg, Germany
| | - Andrea Genre
- Department of Life Sciences and Systems Biology, University of Torino, 10125 Torino, Italy
| | - Marco Giovannetti
- Department of Biology, University of Padova, 35131 Padova, Italy
- Department of Life Sciences and Systems Biology, University of Torino, 10125 Torino, Italy
| | - Lorella Navazio
- Department of Biology, University of Padova, 35131 Padova, Italy
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3
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Leemann S, Schneider-Warme F, Kleinlogel S. Cardiac optogenetics: shining light on signaling pathways. Pflugers Arch 2023; 475:1421-1437. [PMID: 38097805 PMCID: PMC10730638 DOI: 10.1007/s00424-023-02892-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 11/23/2023] [Accepted: 11/24/2023] [Indexed: 12/21/2023]
Abstract
In the early 2000s, the field of neuroscience experienced a groundbreaking transformation with the advent of optogenetics. This innovative technique harnesses the properties of naturally occurring and genetically engineered rhodopsins to confer light sensitivity upon target cells. The remarkable spatiotemporal precision offered by optogenetics has provided researchers with unprecedented opportunities to dissect cellular physiology, leading to an entirely new level of investigation. Initially revolutionizing neuroscience, optogenetics quickly piqued the interest of the wider scientific community, and optogenetic applications were expanded to cardiovascular research. Over the past decade, researchers have employed various optical tools to observe, regulate, and steer the membrane potential of excitable cells in the heart. Despite these advancements, achieving control over specific signaling pathways within the heart has remained an elusive goal. Here, we review the optogenetic tools suitable to control cardiac signaling pathways with a focus on GPCR signaling, and delineate potential applications for studying these pathways, both in healthy and diseased hearts. By shedding light on these exciting developments, we hope to contribute to the ongoing progress in basic cardiac research to facilitate the discovery of novel therapeutic possibilities for treating cardiovascular pathologies.
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Affiliation(s)
- Siri Leemann
- Institute of Physiology, University of Bern, Bern, Switzerland.
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen, and Medical Faculty, University of Freiburg, Freiburg, Germany.
| | - Franziska Schneider-Warme
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen, and Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Sonja Kleinlogel
- Institute of Physiology, University of Bern, Bern, Switzerland
- F. Hoffmann-La Roche, Translational Medicine Neuroscience, Basel, Switzerland
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4
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Alonso MT, Torres-Vidal P, Calvo B, Rodriguez C, Delrio-Lorenzo A, Rojo-Ruiz J, Garcia-Sancho J, Patel S. Use of aequorin-based indicators for monitoring Ca 2+ in acidic organelles. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119481. [PMID: 37142127 DOI: 10.1016/j.bbamcr.2023.119481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/22/2023] [Accepted: 04/26/2023] [Indexed: 05/06/2023]
Abstract
Over the last years, there is accumulating evidence that acidic organelles can accumulate and release Ca2+ upon cell activation. Hence, reliable recording of Ca2+ dynamics in these compartments is essential for understanding the physiopathological aspects of acidic organelles. Genetically encoded Ca2+ indicators (GECIs) are valuable tools to monitor Ca2+ in specific locations, although their use in acidic compartments is challenging due to the pH sensitivity of most available fluorescent GECIs. By contrast, bioluminescent GECIs have a combination of features (marginal pH sensitivity, low background, no phototoxicity, no photobleaching, high dynamic range and tunable affinity) that render them advantageous to achieve an enhanced signal-to-noise ratio in acidic compartments. This article reviews the use of bioluminescent aequorin-based GECIs targeted to acidic compartments. A need for more measurements in highly acidic compartments is identified.
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Affiliation(s)
- M T Alonso
- Unidad de Excelencia, Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain.
| | - P Torres-Vidal
- Unidad de Excelencia, Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain
| | - B Calvo
- Unidad de Excelencia, Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain
| | - C Rodriguez
- Unidad de Excelencia, Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain
| | - A Delrio-Lorenzo
- Universidad Alfonso X el Sabio, Madrid, Avenida Universidad, 1, 28691 Villanueva de la Cañada, Madrid, Spain
| | - J Rojo-Ruiz
- Unidad de Excelencia, Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain
| | - J Garcia-Sancho
- Unidad de Excelencia, Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain
| | - S Patel
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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5
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Poggio E, Vallese F, Hartel AJW, Morgenstern TJ, Kanner SA, Rauh O, Giamogante F, Barazzuol L, Shepard KL, Colecraft HM, Clarke OB, Brini M, Calì T. Perturbation of the host cell Ca 2+ homeostasis and ER-mitochondria contact sites by the SARS-CoV-2 structural proteins E and M. Cell Death Dis 2023; 14:297. [PMID: 37120609 PMCID: PMC10148623 DOI: 10.1038/s41419-023-05817-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 04/11/2023] [Accepted: 04/18/2023] [Indexed: 05/01/2023]
Abstract
Coronavirus disease (COVID-19) is a contagious respiratory disease caused by the SARS-CoV-2 virus. The clinical phenotypes are variable, ranging from spontaneous recovery to serious illness and death. On March 2020, a global COVID-19 pandemic was declared by the World Health Organization (WHO). As of February 2023, almost 670 million cases and 6,8 million deaths have been confirmed worldwide. Coronaviruses, including SARS-CoV-2, contain a single-stranded RNA genome enclosed in a viral capsid consisting of four structural proteins: the nucleocapsid (N) protein, in the ribonucleoprotein core, the spike (S) protein, the envelope (E) protein, and the membrane (M) protein, embedded in the surface envelope. In particular, the E protein is a poorly characterized viroporin with high identity amongst all the β-coronaviruses (SARS-CoV-2, SARS-CoV, MERS-CoV, HCoV-OC43) and a low mutation rate. Here, we focused our attention on the study of SARS-CoV-2 E and M proteins, and we found a general perturbation of the host cell calcium (Ca2+) homeostasis and a selective rearrangement of the interorganelle contact sites. In vitro and in vivo biochemical analyses revealed that the binding of specific nanobodies to soluble regions of SARS-CoV-2 E protein reversed the observed phenotypes, suggesting that the E protein might be an important therapeutic candidate not only for vaccine development, but also for the clinical management of COVID designing drug regimens that, so far, are very limited.
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Affiliation(s)
- Elena Poggio
- Department of Biology, University of Padova, Padova, Italy
| | - Francesca Vallese
- Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY, USA
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Andreas J W Hartel
- Department of Electrical Engineering, Columbia University, New York, NY, USA
| | - Travis J Morgenstern
- Department of Molecular Pharmacology and Therapeutics, Columbia University Irving Medical Center, New York, NY, USA
| | - Scott A Kanner
- Doctoral Program in Neurobiology and Behavior, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Oliver Rauh
- Membrane Biophysics, Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Flavia Giamogante
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Lucia Barazzuol
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Kenneth L Shepard
- Department of Electrical Engineering, Columbia University, New York, NY, USA
| | - Henry M Colecraft
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
- Department of Molecular Pharmacology and Therapeutics, Columbia University Irving Medical Center, New York, NY, USA
- Doctoral Program in Neurobiology and Behavior, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Oliver Biggs Clarke
- Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY, USA
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Marisa Brini
- Department of Biology, University of Padova, Padova, Italy
- Study Center for Neurodegeneration (CESNE), University of Padova, Padova, Italy
| | - Tito Calì
- Department of Biomedical Sciences, University of Padova, Padova, Italy.
- Study Center for Neurodegeneration (CESNE), University of Padova, Padova, Italy.
- Padova Neuroscience Center (PNC), University of Padova, Padova, Italy.
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6
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Sluysmans S, Salmaso A, Rouaud F, Méan I, Brini M, Citi S. The PLEKHA7-PDZD11 complex regulates the localization of the calcium pump PMCA and calcium handling in cultured cells. J Biol Chem 2022; 298:102138. [PMID: 35714771 PMCID: PMC9307954 DOI: 10.1016/j.jbc.2022.102138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 06/05/2022] [Accepted: 06/06/2022] [Indexed: 01/11/2023] Open
Abstract
The plasma membrane calcium ATPase (PMCA) extrudes calcium from the cytosol to the extracellular space to terminate calcium-dependent signaling. Although the distribution of PMCA is crucial for its function, the molecular mechanisms that regulate the localization of PMCA isoforms are not well understood. PLEKHA7 is implicated by genetic studies in hypertension and the regulation of calcium handling. PLEKHA7 recruits the small adapter protein PDZD11 to adherens junctions, and together they control the trafficking and localization of plasma membrane associated proteins, including the Menkes copper ATPase. Since PDZD11 binds to the C-terminal domain of b-isoforms of PMCA, PDZD11 and its interactor PLEKHA7 could control the localization and activity of PMCA. Here, we test this hypothesis using cultured cell model systems. We show using immunofluorescence microscopy and a surface biotinylation assay that KO of either PLEKHA7 or PDZD11 in mouse kidney collecting duct epithelial cells results in increased accumulation of endogenous PMCA at lateral cell–cell contacts and PDZ-dependent ectopic apical localization of exogenous PMCA4x/b isoform. In HeLa cells, coexpression of PDZD11 reduces membrane accumulation of overexpressed PMCA4x/b, and analysis of cytosolic calcium transients shows that PDZD11 counteracts calcium extrusion activity of overexpressed PMCA4x/b, but not PMCA4x/a, which lacks the PDZ-binding motif. Moreover, KO of PDZD11 in either endothelial (bEnd.3) or epithelial (mouse kidney collecting duct) cells increases the rate of calcium extrusion. Collectively, these results suggest that the PLEKHA7–PDZD11 complex modulates calcium homeostasis by regulating the localization of PMCA.
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Affiliation(s)
- Sophie Sluysmans
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Andrea Salmaso
- Department of Biology, University of Padua, Padua, Italy
| | - Florian Rouaud
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Isabelle Méan
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Marisa Brini
- Department of Biology, University of Padua, Padua, Italy.
| | - Sandra Citi
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland.
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7
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Caputo I, Caroccia B, Frasson I, Poggio E, Zamberlan S, Morpurgo M, Seccia TM, Calì T, Brini M, Richter SN, Rossi GP. Angiotensin II Promotes SARS-CoV-2 Infection via Upregulation of ACE2 in Human Bronchial Cells. Int J Mol Sci 2022; 23:ijms23095125. [PMID: 35563515 PMCID: PMC9102833 DOI: 10.3390/ijms23095125] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/01/2022] [Accepted: 05/02/2022] [Indexed: 12/15/2022] Open
Abstract
Blockers of the renin-angiotensin system (RAS) have been reported to increase the angiotensin converting enzyme (ACE)2, the cellular receptor of SARS-CoV-2, and thus the risk and course of COVID-19. Therefore, we investigated if angiotensin (Ang) II and RAS blockers affected ACE2 expression and SARS-CoV-2 infectivity in human epithelial bronchial Calu-3 cells. By infectivity and spike-mediated cell–cell fusion assays, we showed that Ang II acting on the angiotensin type 1 receptor markedly increased ACE2 at mRNA and protein levels, resulting in enhanced SARS-CoV-2 cell entry. These effects were abolished by irbesartan and not affected by the blockade of ACE-1-mediated Ang II formation with ramipril, and of ACE2- mediated Ang II conversion into Ang 1-7 with MLN-4760. Thus, enhanced Ang II production in patients with an activated RAS might expose to a greater spread of COVID-19 infection in lung cells. The protective action of Angiotensin type 1 receptor antagonists (ARBs) documented in these studies provides a mechanistic explanation for the lack of worse outcomes in high-risk COVID-19 patients on RAS blockers.
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Affiliation(s)
- Ilaria Caputo
- Specialized Center for Blood Pressure Disorders-Regione Veneto and Internal Emergency Medicine Unit, Department of Medicine-DIMED, University of Padua, 35128 Padua, Italy; (I.C.); (B.C.); (S.Z.); (T.M.S.)
| | - Brasilina Caroccia
- Specialized Center for Blood Pressure Disorders-Regione Veneto and Internal Emergency Medicine Unit, Department of Medicine-DIMED, University of Padua, 35128 Padua, Italy; (I.C.); (B.C.); (S.Z.); (T.M.S.)
| | - Ilaria Frasson
- Department of Molecular Medicine-DMM, University of Padua, 35121 Padua, Italy; (I.F.); (S.N.R.)
| | - Elena Poggio
- Department of Biology, University of Padua, 35131 Padua, Italy; (E.P.); (M.B.)
| | - Stefania Zamberlan
- Specialized Center for Blood Pressure Disorders-Regione Veneto and Internal Emergency Medicine Unit, Department of Medicine-DIMED, University of Padua, 35128 Padua, Italy; (I.C.); (B.C.); (S.Z.); (T.M.S.)
| | - Margherita Morpurgo
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, 35131 Padua, Italy;
| | - Teresa M. Seccia
- Specialized Center for Blood Pressure Disorders-Regione Veneto and Internal Emergency Medicine Unit, Department of Medicine-DIMED, University of Padua, 35128 Padua, Italy; (I.C.); (B.C.); (S.Z.); (T.M.S.)
| | - Tito Calì
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy;
| | - Marisa Brini
- Department of Biology, University of Padua, 35131 Padua, Italy; (E.P.); (M.B.)
| | - Sara N. Richter
- Department of Molecular Medicine-DMM, University of Padua, 35121 Padua, Italy; (I.F.); (S.N.R.)
| | - Gian Paolo Rossi
- Specialized Center for Blood Pressure Disorders-Regione Veneto and Internal Emergency Medicine Unit, Department of Medicine-DIMED, University of Padua, 35128 Padua, Italy; (I.C.); (B.C.); (S.Z.); (T.M.S.)
- Correspondence:
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8
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Serrat R, Oliveira-Pinto A, Marsicano G, Pouvreau S. Imaging mitochondrial calcium dynamics in the central nervous system. J Neurosci Methods 2022; 373:109560. [PMID: 35320763 DOI: 10.1016/j.jneumeth.2022.109560] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 03/04/2022] [Accepted: 03/06/2022] [Indexed: 12/28/2022]
Abstract
Mitochondrial calcium handling is a particularly active research area in the neuroscience field, as it plays key roles in the regulation of several functions of the central nervous system, such as synaptic transmission and plasticity, astrocyte calcium signaling, neuronal activity… In the last few decades, a panel of techniques have been developed to measure mitochondrial calcium dynamics, relying mostly on photonic microscopy, and including synthetic sensors, hybrid sensors and genetically encoded calcium sensors. The goal of this review is to endow the reader with a deep knowledge of the historical and latest tools to monitor mitochondrial calcium events in the brain, as well as a comprehensive overview of the current state of the art in brain mitochondrial calcium signaling. We will discuss the main calcium probes used in the field, their mitochondrial targeting strategies, their key properties and major drawbacks. In addition, we will detail the main roles of mitochondrial calcium handling in neuronal tissues through an extended report of the recent studies using mitochondrial targeted calcium sensors in neuronal and astroglial cells, in vitro and in vivo.
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Affiliation(s)
- Roman Serrat
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1215 NeuroCentre Magendie, France; University of Bordeaux, Bordeaux 33077, France
| | - Alexandre Oliveira-Pinto
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1215 NeuroCentre Magendie, France; University of Bordeaux, Bordeaux 33077, France
| | - Giovanni Marsicano
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1215 NeuroCentre Magendie, France; University of Bordeaux, Bordeaux 33077, France
| | - Sandrine Pouvreau
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1215 NeuroCentre Magendie, France; University of Bordeaux, Bordeaux 33077, France.
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9
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Cortese E, Moscatiello R, Pettiti F, Carraretto L, Baldan B, Frigerio L, Vothknecht UC, Szabo I, De Stefani D, Brini M, Navazio L. Monitoring calcium handling by the plant endoplasmic reticulum with a low-Ca 2+ -affinity targeted aequorin reporter. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 109:1014-1027. [PMID: 34837294 PMCID: PMC9299891 DOI: 10.1111/tpj.15610] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 10/05/2021] [Accepted: 11/22/2021] [Indexed: 05/15/2023]
Abstract
Precise measurements of dynamic changes in free Ca2+ concentration in the lumen of the plant endoplasmic reticulum (ER) have been lacking so far, despite increasing evidence for the contribution of this intracellular compartment to Ca2+ homeostasis and signalling in the plant cell. In the present study, we targeted an aequorin chimera with reduced Ca2+ affinity to the ER membrane and facing the ER lumen. To this aim, the cDNA for a low-Ca2+ -affinity aequorin variant (AEQmut) was fused to the nucleotide sequence encoding a non-cleavable N-terminal ER signal peptide (fl2). The correct targeting of fl2-AEQmut was confirmed by immunocytochemical analyses in transgenic Arabidopsis thaliana (Arabidopsis) seedlings. An experimental protocol well-established in animal cells - consisting of ER Ca2+ depletion during photoprotein reconstitution followed by ER Ca2+ refilling - was applied to carry out ER Ca2+ measurements in planta. Rapid and transient increases of the ER luminal Ca2+ concentration ([Ca2+ ]ER ) were recorded in response to different environmental stresses, displaying stimulus-specific Ca2+ signatures. The comparative analysis of ER and chloroplast Ca2+ dynamics indicates a complex interplay of these organelles in shaping cytosolic Ca2+ signals during signal transduction events. Our data highlight significant differences in basal [Ca2+ ]ER and Ca2+ handling by plant ER compared to the animal counterpart. The set-up of an ER-targeted aequorin chimera extends and complements the currently available toolkit of organelle-targeted Ca2+ indicators by adding a reporter that improves our quantitative understanding of Ca2+ homeostasis in the plant endomembrane system.
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Affiliation(s)
- Enrico Cortese
- Department of BiologyUniversity of PadovaPadova35131Italy
| | | | | | | | - Barbara Baldan
- Department of BiologyUniversity of PadovaPadova35131Italy
- Botanical GardenUniversity of PadovaPadova35123Italy
| | | | - Ute C. Vothknecht
- Plant Cell BiologyInstitute of Cellular and Molecular BotanyUniversity of BonnBonnD‐53115Germany
| | - Ildiko Szabo
- Department of BiologyUniversity of PadovaPadova35131Italy
- Botanical GardenUniversity of PadovaPadova35123Italy
| | - Diego De Stefani
- Department of Biomedical SciencesUniversity of PadovaPadova35131Italy
| | - Marisa Brini
- Department of BiologyUniversity of PadovaPadova35131Italy
| | - Lorella Navazio
- Department of BiologyUniversity of PadovaPadova35131Italy
- Botanical GardenUniversity of PadovaPadova35123Italy
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10
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Calì T, Brini M. Quantification of organelle contact sites by split-GFP-based contact site sensors (SPLICS) in living cells. Nat Protoc 2021; 16:5287-5308. [PMID: 34686857 DOI: 10.1038/s41596-021-00614-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 08/09/2021] [Indexed: 02/08/2023]
Abstract
Membrane contact sites between organelles are essential for maintaining cellular homeostasis, which requires the continuous exchange of signaling molecules, ions, nutrients and lipids. Alterations of different contact sites are associated with a wide spectrum of human diseases. However, visualizing and quantifying these contact sites remains a challenge. This protocol describes the use of split-GFP-based contact site sensors (SPLICS) in microscopy applications for mapping organelle contact sites both in fixed and living cells. SPLICS sensors are engineered to express equimolar amounts of the organelle-targeted nonfluorescent β11 and GFP1-10 portions of the split-GFP protein in a single vector, and are capable of reconstituting fluorescence when two opposing membranes come into proximity. Reconstitution will occur only over the cell volume at defined contact sites resulting in a bright signal that can be detected easily and quantified automatically with specific custom-made plugins. The use of minimal targeting sequences facilitates targeting specificity and membrane coverage, avoiding artifacts due to full-length fusion protein overexpression and, thus, possible perturbations of the cell's physiology. SPLICS sensors engineered to simultaneously detect multiple contact sites within the same cell have been generated by exploiting the ability of the β11 GFP fragment to reconstitute different color-shifted variants of the GFP1-10 fragment. Here, we describe a detailed protocol to set up SPLICS expression in living cells (2-3 d), detection and acquisition (1 d), and automated quantification with custom plugins (1-2 d). We also advise on construct design and characterization for novel organelle contacts.
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Affiliation(s)
- Tito Calì
- Department of Biomedical Sciences, University of Padua, Padua, Italy.
- Padua Neuroscience Center (PNC), University of Padua, Padua, Italy.
| | - Marisa Brini
- Department of Biology, University of Padua, Padua, Italy.
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11
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Pivato M, Ballottari M. Chlamydomonas reinhardtii cellular compartments and their contribution to intracellular calcium signalling. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:5312-5335. [PMID: 34077536 PMCID: PMC8318260 DOI: 10.1093/jxb/erab212] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 05/11/2021] [Indexed: 05/12/2023]
Abstract
Calcium (Ca2+)-dependent signalling plays a well-characterized role in the response to different environmental stimuli, in both plant and animal cells. In the model organism for green algae, Chlamydomonas reinhardtii, Ca2+ signals were reported to have a crucial role in different physiological processes, such as stress responses, photosynthesis, and flagella functions. Recent reports identified the underlying components of the Ca2+ signalling machinery at the level of specific subcellular compartments and reported in vivo imaging of cytosolic Ca2+ concentration in response to environmental stimuli. The characterization of these Ca2+-related mechanisms and proteins in C. reinhardtii is providing knowledge on how microalgae can perceive and respond to environmental stimuli, but also on how this Ca2+ signalling machinery has evolved. Here, we review current knowledge on the cellular mechanisms underlying the generation, shaping, and decoding of Ca2+ signals in C. reinhardtii, providing an overview of the known and possible molecular players involved in the Ca2+ signalling of its different subcellular compartments. The advanced toolkits recently developed to measure time-resolved Ca2+ signalling in living C. reinhardtii cells are also discussed, suggesting how they can improve the study of the role of Ca2+ signals in the cellular response of microalgae to environmental stimuli.
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Affiliation(s)
- Matteo Pivato
- Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134 Verona, Italy
| | - Matteo Ballottari
- Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134 Verona, Italy
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12
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Calvo-Rodriguez M, Kharitonova EK, Bacskai BJ. In vivo brain imaging of mitochondrial Ca 2+ in neurodegenerative diseases with multiphoton microscopy. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2021; 1868:118998. [PMID: 33684410 PMCID: PMC8057769 DOI: 10.1016/j.bbamcr.2021.118998] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/22/2021] [Indexed: 10/22/2022]
Abstract
Mitochondria are involved in a large number of essential roles related to neuronal function. Ca2+ handling by mitochondria is critical for many of these functions, including energy production and cellular fate. Conversely, mitochondrial Ca2+ mishandling has been related to a variety of neurodegenerative diseases. Investigating mitochondrial Ca2+ dynamics is essential for advancing our understanding of the role of intracellular mitochondrial Ca2+ signals in physiology and pathology. Improved Ca2+ indicators, and the ability to target them to different cells and compartments, have emerged as useful tools for analysis of Ca2+ signals in living organisms. Combined with state-of-the-art techniques such as multiphoton microscopy, they allow for the study of mitochondrial Ca2+ dynamics in vivo in mouse models of the disease. Here, we provide an overview of the Ca2+ transporters/ion channels in mitochondrial membranes, and the involvement of mitochondrial Ca2+ in neurodegenerative diseases followed by a summary of the main tools available to evaluate mitochondrial Ca2+ dynamics in vivo using the aforementioned technique.
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Affiliation(s)
- Maria Calvo-Rodriguez
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 114, 16th St, Charlestown, MA, 02129, USA.
| | - Elizabeth K Kharitonova
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 114, 16th St, Charlestown, MA, 02129, USA
| | - Brian J Bacskai
- Alzheimer Research Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 114, 16th St, Charlestown, MA, 02129, USA
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13
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Vallese F, Catoni C, Cieri D, Barazzuol L, Ramirez O, Calore V, Bonora M, Giamogante F, Pinton P, Brini M, Calì T. An expanded palette of improved SPLICS reporters detects multiple organelle contacts in vitro and in vivo. Nat Commun 2020; 11:6069. [PMID: 33247103 PMCID: PMC7699637 DOI: 10.1038/s41467-020-19892-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 11/04/2020] [Indexed: 12/21/2022] Open
Abstract
Membrane contact sites between virtually any known organelle have been documented and, in the last decades, their study received momentum due to their importance for fundamental activities of the cell and for the subtle comprehension of many human diseases. The lack of tools to finely image inter-organelle proximity hindered our understanding on how these subcellular communication hubs mediate and regulate cell homeostasis. We develop an improved and expanded palette of split-GFP-based contact site sensors (SPLICS) for the detection of single and multiple organelle contact sites within a scalable distance range. We demonstrate their flexibility under physiological conditions and in living organisms.
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Affiliation(s)
- Francesca Vallese
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Domenico Cieri
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Lucia Barazzuol
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Omar Ramirez
- Department of Neurobiology, Interdisciplinary Center for Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Valentina Calore
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Massimo Bonora
- Department of Morphology, Surgery and Experimental Medicine, Section of General Pathology, University of Ferrara, Ferrara, Italy.,Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Flavia Giamogante
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Paolo Pinton
- Department of Morphology, Surgery and Experimental Medicine, Section of General Pathology, University of Ferrara, Ferrara, Italy.,Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Marisa Brini
- Department of Biology, University of Padova, Padova, Italy.
| | - Tito Calì
- Department of Biomedical Sciences, University of Padova, Padova, Italy. .,Padova Neuroscience Center (PNC), University of Padova, Padova, Italy.
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14
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Genovese I, Giamogante F, Barazzuol L, Battista T, Fiorillo A, Vicario M, D'Alessandro G, Cipriani R, Limatola C, Rossi D, Sorrentino V, Poser E, Mosca L, Squitieri F, Perluigi M, Arena A, van Petegem F, Tito C, Fazi F, Giorgi C, Calì T, Ilari A, Colotti G. Sorcin is an early marker of neurodegeneration, Ca 2+ dysregulation and endoplasmic reticulum stress associated to neurodegenerative diseases. Cell Death Dis 2020; 11:861. [PMID: 33060591 PMCID: PMC7566454 DOI: 10.1038/s41419-020-03063-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 09/16/2020] [Accepted: 09/18/2020] [Indexed: 12/12/2022]
Abstract
Dysregulation of calcium signaling is emerging as a key feature in the pathogenesis of neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and Huntington’s disease (HD), and targeting this process may be therapeutically beneficial. Under this perspective, it is important to study proteins that regulate calcium homeostasis in the cell. Sorcin is one of the most expressed calcium-binding proteins in the human brain; its overexpression increases endoplasmic reticulum (ER) calcium concentration and decreases ER stress in the heart and in other cellular types. Sorcin has been hypothesized to be involved in neurodegenerative diseases, since it may counteract the increased cytosolic calcium levels associated with neurodegeneration. In the present work, we show that Sorcin expression levels are strongly increased in cellular, animal, and human models of AD, PD, and HD, vs. normal cells. Sorcin partially colocalizes with RyRs in neurons and microglia cells; functional experiments with microsomes containing high amounts of RyR2 and RyR3, respectively, show that Sorcin is able to regulate these ER calcium channels. The molecular basis of the interaction of Sorcin with RyR2 and RyR3 is demonstrated by SPR. Sorcin also interacts with other ER proteins as SERCA2 and Sigma-1 receptor in a calcium-dependent fashion. We also show that Sorcin regulates ER calcium transients: Sorcin increases the velocity of ER calcium uptake (increasing SERCA activity). The data presented here demonstrate that Sorcin may represent both a novel early marker of neurodegenerative diseases and a response to cellular stress dependent on neurodegeneration.
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Affiliation(s)
- Ilaria Genovese
- Department of Medical Sciences, Laboratory for Technology of Advanced Therapies (LTTA) University of Ferrara, Ferrara, Italy
| | - Flavia Giamogante
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Padova Neuroscience Center (PNC), University of Padova, Padova, Italy
| | - Lucia Barazzuol
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Padova Neuroscience Center (PNC), University of Padova, Padova, Italy
| | - Theo Battista
- Department of Biochemical Sciences "A. Rossi Fanelli", University Sapienza of Rome, Rome, Italy
| | - Annarita Fiorillo
- Department of Biochemical Sciences "A. Rossi Fanelli", University Sapienza of Rome, Rome, Italy
| | - Mattia Vicario
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Giuseppina D'Alessandro
- Department of Physiology and Pharmacology, University of Rome "Sapienza", Rome, Italy.,IRCCS Neuromed, Pozzilli, Isernia, Italy
| | - Raffaela Cipriani
- Department of Physiology and Pharmacology, University of Rome "Sapienza", Rome, Italy
| | - Cristina Limatola
- IRCCS Neuromed, Pozzilli, Isernia, Italy.,Department of Physiology and Pharmacology, Sapienza University, Laboratory Affiliated to Istituto Pasteur Italia - Rome, Rome, Italy
| | - Daniela Rossi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Vincenzo Sorrentino
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Elena Poser
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Luciana Mosca
- Department of Biochemical Sciences "A. Rossi Fanelli", University Sapienza of Rome, Rome, Italy
| | - Ferdinando Squitieri
- Huntington's and Rare Diseases Unit, IRCCS Ospedale Casa Sollievo della Sofferenza, Rome, Italy
| | - Marzia Perluigi
- Department of Biochemical Sciences "A. Rossi Fanelli", University Sapienza of Rome, Rome, Italy
| | - Andrea Arena
- Department of Biochemical Sciences "A. Rossi Fanelli", University Sapienza of Rome, Rome, Italy
| | - Filip van Petegem
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Claudia Tito
- Department of Anatomical, Histological, Forensic & Orthopedic Sciences, Section of Histology & Medical Embryology, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Rome, Italy
| | - Francesco Fazi
- Department of Anatomical, Histological, Forensic & Orthopedic Sciences, Section of Histology & Medical Embryology, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Rome, Italy
| | - Carlotta Giorgi
- Department of Medical Sciences, Laboratory for Technology of Advanced Therapies (LTTA) University of Ferrara, Ferrara, Italy
| | - Tito Calì
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,Padova Neuroscience Center (PNC), University of Padova, Padova, Italy
| | - Andrea Ilari
- Institute of Molecular Biology and Pathology, Italian National Research Council, IBPM-CNR, Rome, Italy.
| | - Gianni Colotti
- Institute of Molecular Biology and Pathology, Italian National Research Council, IBPM-CNR, Rome, Italy.
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15
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Ruffinatti FA, Lomazzi S, Nardo L, Santoro R, Martemiyanov A, Dionisi M, Tapella L, Genazzani AA, Lim D, Distasi C, Caccia M. Assessment of a Silicon-Photomultiplier-Based Platform for the Measurement of Intracellular Calcium Dynamics with Targeted Aequorin. ACS Sens 2020; 5:2388-2397. [PMID: 32701269 PMCID: PMC8009593 DOI: 10.1021/acssensors.0c00277] [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] [Indexed: 11/30/2022]
Abstract
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Ca2+ is among the most important intracellular second
messengers participating in a plethora of biological processes, and
the measurement of Ca2+ fluctuations is significant in
the phenomenology of the underlying processes. Aequorin-based Ca2+ probes represent an invaluable tool for reliable measurement
of Ca2+ concentrations and dynamics in different subcellular
compartments. However, their use is limited due to the lack on the
market of ready-to-use, cost-effective, and portable devices for the
detection and readout of the low-intensity bioluminescence signal
produced by these probes. Silicon photomultipliers (SiPMs) are rapidly
evolving solid-state sensors for low light detection, with single
photon sensitivity and photon number resolving capability, featuring
low cost, low voltage, and compact format. Thus, they may represent
the sensors of choice for the development of such devices and, more
in general, of a new generation of multipurpose bioluminescence detectors
suitable for cell biology studies. Ideally, a detector customized
for these purposes must combine high dynamic range with high fidelity
in reconstructing the light intensity signal temporal profile. In
this article, the ability to perform aequorin-based intracellular
Ca2+ measurements using a multipurpose, low-cost setup
exploiting SiPMs as the sensors is demonstrated. SiPMs turn out to
assure performances comparable to those exhibited by a custom-designed
photomultiplier tube-based aequorinometer. Moreover, the flexibility
of SiPM-based devices might pave the way toward routinely and wide
scale application of innovative biophysical protocols.
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Affiliation(s)
| | - Samuela Lomazzi
- Department of Science and High Technology, Università degli Studi dell’Insubria, Via Valleggio 11, Como 22100, Italy
| | - Luca Nardo
- Department of Science and High Technology, Università degli Studi dell’Insubria, Via Valleggio 11, Como 22100, Italy
| | - Romualdo Santoro
- Department of Science and High Technology, Università degli Studi dell’Insubria, Via Valleggio 11, Como 22100, Italy
| | - Alexander Martemiyanov
- Department of Science and High Technology, Università degli Studi dell’Insubria, Via Valleggio 11, Como 22100, Italy
- ITEP, Bol’shaya Cheremushkinskaya Ulitsa, 25, Moscow 117218, Russia
| | - Marianna Dionisi
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Via Bovio 6, Novara 28100, Italy
| | - Laura Tapella
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Via Bovio 6, Novara 28100, Italy
| | - Armando A. Genazzani
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Via Bovio 6, Novara 28100, Italy
| | - Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Via Bovio 6, Novara 28100, Italy
| | - Carla Distasi
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Via Bovio 6, Novara 28100, Italy
| | - Massimo Caccia
- Department of Science and High Technology, Università degli Studi dell’Insubria, Via Valleggio 11, Como 22100, Italy
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16
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Gökerküçük EB, Tramier M, Bertolin G. Imaging Mitochondrial Functions: from Fluorescent Dyes to Genetically-Encoded Sensors. Genes (Basel) 2020; 11:E125. [PMID: 31979408 PMCID: PMC7073610 DOI: 10.3390/genes11020125] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 12/18/2022] Open
Abstract
Mitochondria are multifunctional organelles that are crucial to cell homeostasis. They constitute the major site of energy production for the cell, they are key players in signalling pathways using secondary messengers such as calcium, and they are involved in cell death and redox balance paradigms. Mitochondria quickly adapt their dynamics and biogenesis rates to meet the varying energy demands of the cells, both in normal and in pathological conditions. Therefore, understanding simultaneous changes in mitochondrial functions is crucial in developing mitochondria-based therapy options for complex pathological conditions such as cancer, neurological disorders, and metabolic syndromes. To this end, fluorescence microscopy coupled to live imaging represents a promising strategy to track these changes in real time. In this review, we will first describe the commonly available tools to follow three key mitochondrial functions using fluorescence microscopy: Calcium signalling, mitochondrial dynamics, and mitophagy. Then, we will focus on how the development of genetically-encoded fluorescent sensors became a milestone for the understanding of these mitochondrial functions. In particular, we will show how these tools allowed researchers to address several biochemical activities in living cells, and with high spatiotemporal resolution. With the ultimate goal of tracking multiple mitochondrial functions simultaneously, we will conclude by presenting future perspectives for the development of novel genetically-encoded fluorescent biosensors.
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Affiliation(s)
| | | | - Giulia Bertolin
- Univ Rennes, CNRS, IGDR [Institut de génétique et développement de Rennes] UMR 6290, F-35000 Rennes, France
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17
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Vicario M, Cieri D, Vallese F, Catoni C, Barazzuol L, Berto P, Grinzato A, Barbieri L, Brini M, Calì T. A split-GFP tool reveals differences in the sub-mitochondrial distribution of wt and mutant alpha-synuclein. Cell Death Dis 2019; 10:857. [PMID: 31719530 PMCID: PMC6851186 DOI: 10.1038/s41419-019-2092-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 10/11/2019] [Accepted: 10/28/2019] [Indexed: 01/01/2023]
Abstract
Parkinson’s disease (PD), the second most common neurodegenerative disorder, is characterized by dopaminergic neuronal loss that initiates in the substantia nigra pars compacta and by the formation of intracellular inclusions mainly constituted by aberrant α-synuclein (α-syn) deposits known as Lewy bodies. Most cases of PD are sporadic, but about 10% are familial, among them those caused by mutations in SNCA gene have an autosomal dominant transmission. SNCA encodes α-syn, a small 140-amino acids protein that, under physiological conditions, is mainly localized at the presynaptic terminals. It is prevalently cytosolic, but its presence has been reported in the nucleus, in the mitochondria and, more recently, in the mitochondria-associated ER membranes (MAMs). Whether different cellular localizations may reflect specific α-syn activities is presently unclear and its action at mitochondrial level is still a matter of debate. Mounting evidence supports a role for α-syn in several mitochondria-derived activities, among which maintenance of mitochondrial morphology and modulation of complex I and ATP synthase activity. α-syn has been proposed to localize at the outer membrane (OMM), in the intermembrane space (IMS), at the inner membrane (IMM) and in the mitochondrial matrix, but a clear and comparative analysis of the sub-mitochondrial localization of WT and mutant α-syn is missing. Furthermore, the reasons for this spread sub-mitochondrial localization under physiological and pathological circumstances remain elusive. In this context, we decided to selectively monitor the sub-mitochondrial distribution of the WT and PD-related α-syn mutants A53T and A30P by taking advantage from a bimolecular fluorescence complementation (BiFC) approach. We also investigated whether cell stress could trigger α-syn translocation within the different mitochondrial sub-compartments and whether PD-related mutations could impinge on it. Interestingly, the artificial targeting of α-syn WT (but not of the mutants) to the mitochondrial matrix impacts on ATP production, suggesting a potential role within this compartment.
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Affiliation(s)
- Mattia Vicario
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Domenico Cieri
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Francesca Vallese
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Lucia Barazzuol
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Paola Berto
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Laura Barbieri
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Marisa Brini
- Department of Biology, University of Padova, Padova, Italy.
| | - Tito Calì
- Department of Biomedical Sciences, University of Padova, Padova, Italy. .,Padova Neuroscience Center (PNC), University of Padova, Padova, Italy.
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18
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splitGFP Technology Reveals Dose-Dependent ER-Mitochondria Interface Modulation by α-Synuclein A53T and A30P Mutants. Cells 2019; 8:cells8091072. [PMID: 31547305 PMCID: PMC6769576 DOI: 10.3390/cells8091072] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 12/26/2022] Open
Abstract
Familial Parkinson’s disease (PD) is associated with duplication or mutations of α-synuclein gene, whose product is a presynaptic cytosolic protein also found in mitochondria and in mitochondrial-associated ER membranes. We have originally shown the role of α-syn as a modulator of the ER-mitochondria interface and mitochondrial Ca2+ transients, suggesting that, at mild levels of expression, α-syn sustains cell metabolism. Here, we investigated the possibility that α-syn action on ER-mitochondria tethering could be compromised by the presence of PD-related mutations. The clarification of this aspect could contribute to elucidate key mechanisms underlying PD. The findings reported so far are not consistent, possibly because of the different methods used to evaluate ER-mitochondria connectivity. Here, the effects of the PD-related α-syn mutations A53T and A30P on ER-mitochondria relationship were investigated in respect to Ca2+ handling and mitochondrial function using a newly generated SPLICS sensor and aequorin-based Ca2+measurements. We provided evidence that A53T and A30P amino acid substitution does not affect the ability of α-syn to enhance ER/mitochondria tethering and mitochondrial Ca2+ transients, but that this action was lost as soon as a high amount of TAT-delivered A53T and A30P α-syn mutants caused the redistribution of α-syn from cytoplasm to foci. Our results suggest a loss of function mechanism and highlight a possible connection between α-syn and ER-mitochondria Ca2+ cross-talk impairment to the pathogenesis of PD.
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19
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Costa R, Peruzzo R, Bachmann M, Montà GD, Vicario M, Santinon G, Mattarei A, Moro E, Quintana-Cabrera R, Scorrano L, Zeviani M, Vallese F, Zoratti M, Paradisi C, Argenton F, Brini M, Calì T, Dupont S, Szabò I, Leanza L. Impaired Mitochondrial ATP Production Downregulates Wnt Signaling via ER Stress Induction. Cell Rep 2019; 28:1949-1960.e6. [PMID: 31433973 DOI: 10.1016/j.celrep.2019.07.050] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 03/01/2019] [Accepted: 07/16/2019] [Indexed: 02/02/2023] Open
Abstract
Wnt signaling affects fundamental development pathways and, if aberrantly activated, promotes the development of cancers. Wnt signaling is modulated by different factors, but whether the mitochondrial energetic state affects Wnt signaling is unknown. Here, we show that sublethal concentrations of different compounds that decrease mitochondrial ATP production specifically downregulate Wnt/β-catenin signaling in vitro in colon cancer cells and in vivo in zebrafish reporter lines. Accordingly, fibroblasts from a GRACILE syndrome patient and a generated zebrafish model lead to reduced Wnt signaling. We identify a mitochondria-Wnt signaling axis whereby a decrease in mitochondrial ATP reduces calcium uptake into the endoplasmic reticulum (ER), leading to endoplasmic reticulum stress and to impaired Wnt signaling. In turn, the recovery of the ATP level or the inhibition of endoplasmic reticulum stress restores Wnt activity. These findings reveal a mechanism that links mitochondrial energetic metabolism to the control of the Wnt pathway that may be beneficial against several pathologies.
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Affiliation(s)
- Roberto Costa
- Department of Biology, University of Padova, Padova, Italy
| | | | | | | | - Mattia Vicario
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Giulia Santinon
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Andrea Mattarei
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, Italy
| | - Enrico Moro
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Rubén Quintana-Cabrera
- Department of Biology, University of Padova, Padova, Italy; Venetian Institute of Molecular Medicine, Padova, Padova, Italy
| | - Luca Scorrano
- Department of Biology, University of Padova, Padova, Italy; Venetian Institute of Molecular Medicine, Padova, Padova, Italy
| | - Massimo Zeviani
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Francesca Vallese
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Mario Zoratti
- Department of Biomedical Sciences, University of Padova, Padova, Italy; CNR Institute of Neuroscience, Padova, Italy
| | - Cristina Paradisi
- Department of Chemical Sciences, University of Padova, Padova, Italy
| | | | - Marisa Brini
- Department of Biology, University of Padova, Padova, Italy
| | - Tito Calì
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Sirio Dupont
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Ildikò Szabò
- Department of Biology, University of Padova, Padova, Italy; CNR Institute of Neuroscience, Padova, Italy.
| | - Luigi Leanza
- Department of Biology, University of Padova, Padova, Italy.
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20
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High-Throughput Screening Using Photoluminescence Probe to Measure Intracellular Calcium Levels. Methods Mol Biol 2019; 1925:1-14. [PMID: 30674012 DOI: 10.1007/978-1-4939-9018-4_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Abstract
Aequorin, a 22 kDa protein produced by the jellyfish Aequorea victoria, was the first probe used to measure Ca2+ concentrations ([Ca2+]) of specific intracellular organelles in intact cells. After the binding of Ca2+ to three high-affinity binding sites, an irreversible reaction occurs leading to the emission of photons that is proportional to [Ca2+]. While native aequorin is suitable for measuring cytosolic [Ca2+] after cell stimulation in a range from 0.5 to 10 μM, it cannot be used in organelles where [Ca2+] is much higher, such as in the lumen of endoplasmic/sarcoplasmic reticulum (ER/SR) and mitochondria. However, some modifications made on aequorin itself or on coelenterazine, its lipophilic prosthetic luminophore, and the addition of targeting sequences or the fusion with resident proteins allowed the specific organelle localization and the measurements of intra-organelle Ca2+ levels. In the last years, the development of multiwell plate readers has opened the possibility to perform aequorin-based high-throughput screenings and has overcome some limitation of the standard method. Here we present the procedure for expressing, targeting, and reconstituting aequorin in intact cells and for measuring Ca2+ in the bulk cytosol, mitochondria, and ER by a high-throughput screening system.
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Teardo E, Carraretto L, Moscatiello R, Cortese E, Vicario M, Festa M, Maso L, De Bortoli S, Calì T, Vothknecht UC, Formentin E, Cendron L, Navazio L, Szabo I. A chloroplast-localized mitochondrial calcium uniporter transduces osmotic stress in Arabidopsis. NATURE PLANTS 2019; 5:581-588. [PMID: 31182842 DOI: 10.1038/s41477-019-0434-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 04/23/2019] [Indexed: 05/18/2023]
Abstract
Chloroplasts are integral to sensing biotic and abiotic stress in plants, but their role in transducing Ca2+-mediated stress signals remains poorly understood1,2. Here we identify cMCU, a member of the mitochondrial calcium uniporter (MCU) family, as an ion channel mediating Ca2+ flux into chloroplasts in vivo. Using a toolkit of aequorin reporters targeted to chloroplast stroma and the cytosol in cMCU wild-type and knockout lines, we provide evidence that stress-stimulus-specific Ca2+ dynamics in the chloroplast stroma correlate with expression of the channel. Fast downstream signalling events triggered by osmotic stress, involving activation of the mitogen-activated protein kinases (MAPK) MAPK3 and MAPK6, and the transcription factors MYB60 and ethylene-response factor 6 (ERF6), are influenced by cMCU activity. Relative to wild-type plants, cMCU knockouts display increased resistance to long-term water deficit and improved recovery on rewatering. Modulation of stromal Ca2+ in specific processing of stress signals identifies cMCU as a component of plant environmental sensing.
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Affiliation(s)
- Enrico Teardo
- Department of Biology, University of Padova, Padova, Italy
| | | | | | - Enrico Cortese
- Department of Biology, University of Padova, Padova, Italy
| | - Mattia Vicario
- Department of Biology, University of Padova, Padova, Italy
| | | | - Lorenzo Maso
- Department of Biology, University of Padova, Padova, Italy
| | | | - Tito Calì
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Elide Formentin
- Department of Biology, University of Padova, Padova, Italy.
- Botanical Garden, University of Padova, Padova, Italy.
| | - Laura Cendron
- Department of Biology, University of Padova, Padova, Italy
| | - Lorella Navazio
- Department of Biology, University of Padova, Padova, Italy.
- Botanical Garden, University of Padova, Padova, Italy.
| | - Ildiko Szabo
- Department of Biology, University of Padova, Padova, Italy.
- Botanical Garden, University of Padova, Padova, Italy.
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22
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Basso V, Marchesan E, Peggion C, Chakraborty J, von Stockum S, Giacomello M, Ottolini D, Debattisti V, Caicci F, Tasca E, Pegoraro V, Angelini C, Antonini A, Bertoli A, Brini M, Ziviani E. Regulation of ER-mitochondria contacts by Parkin via Mfn2. Pharmacol Res 2018; 138:43-56. [PMID: 30219582 DOI: 10.1016/j.phrs.2018.09.006] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 07/04/2018] [Accepted: 09/06/2018] [Indexed: 12/22/2022]
Abstract
Parkin, an E3 ubiquitin ligase and a Parkinson's disease (PD) related gene, translocates to impaired mitochondria and drives their elimination via autophagy, a process known as mitophagy. Mitochondrial pro-fusion protein Mitofusins (Mfn1 and Mfn2) were found to be a target for Parkin mediated ubiquitination. Mfns are transmembrane GTPase embedded in the outer membrane of mitochondria, which are required on adjacent mitochondria to mediate fusion. In mammals, Mfn2 also forms complexes that are capable of tethering mitochondria to endoplasmic reticulum (ER), a structural feature essential for mitochondrial energy metabolism, calcium (Ca2+) transfer between the organelles and Ca2+ dependent cell death. Despite its fundamental physiological role, the molecular mechanisms that control ER-mitochondria cross talk are obscure. Ubiquitination has recently emerged as a powerful tool to modulate protein function, via regulation of protein subcellular localization and protein ability to interact with other proteins. Ubiquitination is also a reversible mechanism, which can be actively controlled by opposing ubiquitination-deubiquitination events. In this work we found that in Parkin deficient cells and parkin mutant human fibroblasts, the tether between ER and mitochondria is decreased. We identified the site of Parkin dependent ubiquitination and showed that the non-ubiquitinatable Mfn2 mutant fails to restore ER-mitochondria physical and functional interaction. Finally, we took advantage of an established in vivo model of PD to demonstrate that manipulation of ER-mitochondria tethering by expressing an ER-mitochondria synthetic linker is sufficient to rescue the locomotor deficit associated to an in vivo Drosophila model of PD.
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Affiliation(s)
- Valentina Basso
- Department of Biology, University of Padova, Padova, Italy; Fondazione Ospedale San Camillo, IRCCS, Lido di Venezia, Venezia, Italy
| | - Elena Marchesan
- Fondazione Ospedale San Camillo, IRCCS, Lido di Venezia, Venezia, Italy
| | - Caterina Peggion
- Department of Biomedical Science (DSB), University of Padova, Padova, Italy
| | - Joy Chakraborty
- Department of Biology, University of Padova, Padova, Italy; Fondazione Ospedale San Camillo, IRCCS, Lido di Venezia, Venezia, Italy
| | | | | | - Denis Ottolini
- Department of Biology, University of Padova, Padova, Italy
| | - Valentina Debattisti
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | | | - Elisabetta Tasca
- Fondazione Ospedale San Camillo, IRCCS, Lido di Venezia, Venezia, Italy
| | | | - Corrado Angelini
- Fondazione Ospedale San Camillo, IRCCS, Lido di Venezia, Venezia, Italy
| | - Angelo Antonini
- Department of Neuroscience, University of Padova, Padova, Italy
| | - Alessandro Bertoli
- Department of Biomedical Science (DSB), University of Padova, Padova, Italy
| | - Marisa Brini
- Department of Biology, University of Padova, Padova, Italy
| | - Elena Ziviani
- Department of Biology, University of Padova, Padova, Italy; Fondazione Ospedale San Camillo, IRCCS, Lido di Venezia, Venezia, Italy.
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Cieri D, Vicario M, Vallese F, D'Orsi B, Berto P, Grinzato A, Catoni C, De Stefani D, Rizzuto R, Brini M, Calì T. Tau localises within mitochondrial sub-compartments and its caspase cleavage affects ER-mitochondria interactions and cellular Ca 2+ handling. Biochim Biophys Acta Mol Basis Dis 2018; 1864:3247-3256. [PMID: 30006151 DOI: 10.1016/j.bbadis.2018.07.011] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/16/2018] [Accepted: 07/06/2018] [Indexed: 01/21/2023]
Abstract
Intracellular neurofibrillary tangles (NFT) composed by tau and extracellular amyloid beta (Aβ) plaques accumulate in Alzheimer's disease (AD) and contribute to neuronal dysfunction. Mitochondrial dysfunction and neurodegeneration are increasingly considered two faces of the same coin and an early pathological event in AD. Compelling evidence indicates that tau and mitochondria are closely linked and suggests that tau-dependent modulation of mitochondrial functions might be a trigger for the neurodegeneration process; however, whether this occurs either directly or indirectly is not clear. Furthermore, whether tau influences cellular Ca2+ handling and ER-mitochondria cross-talk is yet to be explored. Here, by focusing on wt tau, either full-length (2N4R) or the caspase 3-cleaved form truncated at the C-terminus (2N4RΔC20), we examined the above-mentioned aspects. Using new genetically encoded split-GFP-based tools and organelle-targeted aequorin probes, we assessed: i) tau distribution within the mitochondrial sub-compartments; ii) the effect of tau on the short- (8-10 nm) and the long- (40-50 nm) range ER-mitochondria interactions; and iii) the effect of tau on cytosolic, ER and mitochondrial Ca2+ homeostasis. Our results indicate that a fraction of tau is found at the outer mitochondrial membrane (OMM) and within the inner mitochondrial space (IMS), suggesting a potential tau-dependent regulation of mitochondrial functions. The ER Ca2+ content and the short-range ER-mitochondria interactions were selectively affected by the expression of the caspase 3-cleaved 2N4RΔC20 tau, indicating that Ca2+ mis-handling and defects in the ER-mitochondria communications might be an important pathological event in tau-related dysfunction and thereby contributing to neurodegeneration. Finally, our data provide new insights into the molecular mechanisms underlying tauopathies.
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Affiliation(s)
- Domenico Cieri
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Mattia Vicario
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Francesca Vallese
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Beatrice D'Orsi
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Paola Berto
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | | | - Diego De Stefani
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Marisa Brini
- Department of Biology, University of Padova, Padova, Italy
| | - Tito Calì
- Department of Biomedical Sciences, University of Padova, Padova, Italy; Padova Neuroscience Center (PNC), University of Padova, Padova, Italy.
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24
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Costa A, Navazio L, Szabo I. The contribution of organelles to plant intracellular Calcium signalling. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:4996169. [PMID: 29767757 DOI: 10.1093/jxb/ery185] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Indexed: 05/18/2023]
Abstract
Calcium (Ca2+) is among the most important intracellular messengers in living organisms. Understanding of the players and dynamics of Ca2+ signalling pathways in plants may help to unravel the molecular basis of their exceptional flexibility to respond and to adapt to different stimuli. In the present review we focus on new tools that have recently revolutionized our view of organellar Ca2+ signalling as well as on the current knowledge regarding the pathways mediating Ca2+ fluxes across intracellular membranes. The contribution of organelles and cellular subcompartments to the orchestrated response via Ca2+ signalling within a cell is also discussed, underlining the fact that one of the greatest challenges in the field is the elucidation of how influx and efflux Ca2+ transporters/channels are regulated in a concerted manner to translate specific information into a Ca2+ signature.
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Affiliation(s)
- Alex Costa
- Department of Biosciences, University of Milan, Via G. Celoria, Milan, Italy
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Via G. Celoria, Milan, Italy
| | - Lorella Navazio
- Department of Biology, University of Padova, Via U. Bassi, Padova, Italy
- Botanical Garden, University of Padova, Via Orto Botanico, Padova, Italy
| | - Ildiko Szabo
- Department of Biology, University of Padova, Via U. Bassi, Padova, Italy
- Botanical Garden, University of Padova, Via Orto Botanico, Padova, Italy
- Institute of Neurosciences, Consiglio Nazionale delle Ricerche, Via U. Bassi, Padova, Italy
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25
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SPLICS: a split green fluorescent protein-based contact site sensor for narrow and wide heterotypic organelle juxtaposition. Cell Death Differ 2017; 25:1131-1145. [PMID: 29229997 PMCID: PMC5988678 DOI: 10.1038/s41418-017-0033-z] [Citation(s) in RCA: 160] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 10/17/2017] [Accepted: 10/31/2017] [Indexed: 01/06/2023] Open
Abstract
Contact sites are discrete areas of organelle proximity that coordinate essential physiological processes across membranes, including Ca2+ signaling, lipid biosynthesis, apoptosis, and autophagy. However, tools to easily image inter-organelle proximity over a range of distances in living cells and in vivo are lacking. Here we report a split-GFP-based contact site sensor (SPLICS) engineered to fluoresce when organelles are in proximity. Two SPLICS versions efficiently measured narrow (8–10 nm) and wide (40–50 nm) juxtapositions between endoplasmic reticulum and mitochondria, documenting the existence of at least two types of contact sites in human cells. Narrow and wide ER–mitochondria contact sites responded differently to starvation, ER stress, mitochondrial shape modifications, and changes in the levels of modulators of ER–mitochondria juxtaposition. SPLICS detected contact sites in soma and axons of D. rerio Rohon Beard (RB) sensory neurons invivo, extending its use to analyses of organelle juxtaposition in the whole animal.
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26
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Vicario M, Calì T, Cieri D, Vallese F, Bortolotto R, Lopreiato R, Zonta F, Nardella M, Micalizzi A, Lefeber DJ, Valente EM, Bertini E, Zanotti G, Zanni G, Brini M, Carafoli E. A novel PMCA3 mutation in an ataxic patient with hypomorphic phosphomannomutase 2 (PMM2) heterozygote mutations: Biochemical characterization of the pump defect. Biochim Biophys Acta Mol Basis Dis 2017; 1863:3303-3312. [PMID: 28807751 DOI: 10.1016/j.bbadis.2017.08.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 07/28/2017] [Accepted: 08/09/2017] [Indexed: 11/28/2022]
Abstract
The neuron-restricted isoform 3 of the plasma membrane Ca2+ ATPase plays a major role in the regulation of Ca2+ homeostasis in the brain, where the precise control of Ca2+ signaling is a necessity. Several function-affecting genetic mutations in the PMCA3 pump associated to X-linked congenital cerebellar ataxias have indeed been described. Interestingly, the presence of co-occurring mutations in additional genes suggest their synergistic action in generating the neurological phenotype as digenic modulators of the role of PMCA3 in the pathologies. Here we report a novel PMCA3 mutation (G733R substitution) in the catalytic P-domain of the pump in a patient affected by non-progressive ataxia, muscular hypotonia, dysmetria and nystagmus. Biochemical studies of the pump have revealed impaired ability to control cellular Ca2+ handling both under basal and under stimulated conditions. A combined analysis by homology modeling and molecular dynamics have revealed a role for the mutated residue in maintaining the correct 3D configuration of the local structure of the pump. Mutation analysis in the patient has revealed two additional function-impairing compound heterozygous missense mutations (R123Q and G214S substitution) in phosphomannomutase 2 (PMM2), a protein that catalyzes the isomerization of mannose 6-phosphate to mannose 1-phosphate. These mutations are known to be associated with Type Ia congenital disorder of glycosylation (PMM2-CDG), the most common group of disorders of N-glycosylation. The findings highlight the association of PMCA3 mutations to cerebellar ataxia and strengthen the possibility that PMCAs act as digenic modulators in Ca2+-linked pathologies.
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Affiliation(s)
- Mattia Vicario
- Department of Biomedical Sciences, University of Padova, 35131 Padova, (Italy)
| | - Tito Calì
- Department of Biomedical Sciences, University of Padova, 35131 Padova, (Italy)
| | - Domenico Cieri
- Department of Biomedical Sciences, University of Padova, 35131 Padova, (Italy)
| | - Francesca Vallese
- Department of Biomedical Sciences, University of Padova, 35131 Padova, (Italy)
| | - Raissa Bortolotto
- Department of Biomedical Sciences, University of Padova, 35131 Padova, (Italy)
| | - Raffaele Lopreiato
- Department of Biomedical Sciences, University of Padova, 35131 Padova, (Italy)
| | - Francesco Zonta
- Shanghai Institute of Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China; Department of Biomedical Sciences, Institute of Cell Biology and Neurobiology, Italian National Research Council, 00015, Monterotondo, Rome, Italy
| | - Marta Nardella
- Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | | | - Dirk J Lefeber
- Department of Neurology, Translational Metabolic Laboratory, Donders Institute for Brain, Cognition, and Behavior, Radboudumc, Nijmegen, The Netherlands
| | - Enza Maria Valente
- Neurogenetics Unit, IRCCS Santa Lucia Foundation, Rome, Italy; Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Enrico Bertini
- Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Giuseppe Zanotti
- Department of Biomedical Sciences, University of Padova, 35131 Padova, (Italy)
| | - Ginevra Zanni
- Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
| | - Marisa Brini
- Department of Biology, University of Padova, Italy.
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27
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De Mario A, Peggion C, Massimino ML, Viviani F, Castellani A, Giacomello M, Lim D, Bertoli A, Sorgato MC. The prion protein regulates glutamate-mediated Ca 2+ entry and mitochondrial Ca 2+ accumulation in neurons. J Cell Sci 2017; 130:2736-2746. [PMID: 28701513 DOI: 10.1242/jcs.196972] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 07/05/2017] [Indexed: 01/01/2023] Open
Abstract
The cellular prion protein (PrPC) whose conformational misfolding leads to the production of deadly prions, has a still-unclarified cellular function despite decades of intensive research. Following our recent finding that PrPC limits Ca2+ entry via store-operated Ca2+ channels in neurons, we investigated whether the protein could also control the activity of ionotropic glutamate receptors (iGluRs). To this end, we compared local Ca2+ movements in primary cerebellar granule neurons and cortical neurons transduced with genetically encoded Ca2+ probes and expressing, or not expressing, PrPC Our investigation demonstrated that PrPC downregulates Ca2+ entry through each specific agonist-stimulated iGluR and after stimulation by glutamate. We found that, although PrP-knockout (KO) mitochondria were displaced from the plasma membrane, glutamate addition resulted in a higher mitochondrial Ca2+ uptake in PrP-KO neurons than in their PrPC-expressing counterpart. This was because the increased Ca2+ entry through iGluRs in PrP-KO neurons led to a parallel increase in Ca2+-induced Ca2+ release via ryanodine receptor channels. These data thus suggest that PrPC takes part in the cell apparatus controlling Ca2+ homeostasis, and that PrPC is involved in protecting neurons from toxic Ca2+ overloads.
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Affiliation(s)
- Agnese De Mario
- Department of Biomedical Science, University of Padova, 35131 Padova, Italy
| | - Caterina Peggion
- Department of Biomedical Science, University of Padova, 35131 Padova, Italy
| | - Maria Lina Massimino
- CNR Neuroscience Institute, Department of Biomedical Science, University of Padova, 35131 Padova, Italy
| | - Francesca Viviani
- Department of Biomedical Science, University of Padova, 35131 Padova, Italy
| | - Angela Castellani
- Department of Biomedical Science, University of Padova, 35131 Padova, Italy
| | - Marta Giacomello
- Department of Biology, University of Padova, 35131 Padova, Italy
| | - Dmitry Lim
- Department of Pharmaceutical Science, University of Piemonte Orientale, 28100 Novara, Italy
| | - Alessandro Bertoli
- Department of Biomedical Science, University of Padova, 35131 Padova, Italy
| | - Maria Catia Sorgato
- Department of Biomedical Science, University of Padova, 35131 Padova, Italy .,CNR Neuroscience Institute, Department of Biomedical Science, University of Padova, 35131 Padova, Italy
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Bassett JJ, Monteith GR. Genetically Encoded Calcium Indicators as Probes to Assess the Role of Calcium Channels in Disease and for High-Throughput Drug Discovery. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2017; 79:141-171. [PMID: 28528667 DOI: 10.1016/bs.apha.2017.01.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The calcium ion (Ca2+) is an important signaling molecule implicated in many cellular processes, and the remodeling of Ca2+ homeostasis is a feature of a variety of pathologies. Typical methods to assess Ca2+ signaling in cells often employ small molecule fluorescent dyes, which are sometimes poorly suited to certain applications such as assessment of cellular processes, which occur over long periods (hours or days) or in vivo experiments. Genetically encoded calcium indicators are a set of tools available for the measurement of Ca2+ changes in the cytosol and subcellular compartments, which circumvent some of the inherent limitations of small molecule Ca2+ probes. Recent advances in genetically encoded calcium sensors have greatly increased their ability to provide reliable monitoring of Ca2+ changes in mammalian cells. New genetically encoded calcium indicators have diverse options in terms of targeting, Ca2+ affinity and fluorescence spectra, and this will further enhance their potential use in high-throughput drug discovery and other assays. This review will outline the methods available for Ca2+ measurement in cells, with a focus on genetically encoded calcium sensors. How these sensors will improve our understanding of the deregulation of Ca2+ handling in disease and their application to high-throughput identification of drug leads will also be discussed.
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Affiliation(s)
- John J Bassett
- School of Pharmacy, The University of Queensland, Brisbane, QLD, Australia
| | - Gregory R Monteith
- School of Pharmacy, The University of Queensland, Brisbane, QLD, Australia; Mater Research, The University of Queensland, Brisbane, QLD, Australia.
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29
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Lim D, Bertoli A, Sorgato M, Moccia F. Generation and usage of aequorin lentiviral vectors for Ca2+ measurement in sub-cellular compartments of hard-to-transfect cells. Cell Calcium 2016; 59:228-39. [DOI: 10.1016/j.ceca.2016.03.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 03/01/2016] [Indexed: 12/18/2022]
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30
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Figueroa KP, Paul S, Calì T, Lopreiato R, Karan S, Frizzarin M, Ames D, Zanni G, Brini M, Dansithong W, Milash B, Scoles DR, Carafoli E, Pulst SM. Spontaneous shaker rat mutant - a new model for X-linked tremor/ataxia. Dis Model Mech 2016; 9:553-62. [PMID: 27013529 PMCID: PMC4892658 DOI: 10.1242/dmm.022848] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 02/29/2016] [Indexed: 12/18/2022] Open
Abstract
The shaker rat is an X-linked recessive spontaneous model of progressive Purkinje cell (PC) degeneration exhibiting a shaking ataxia and wide stance. Generation of Wistar Furth (WF)/Brown Norwegian (BN) F1 hybrids and genetic mapping of F2 sib-sib offspring using polymorphic markers narrowed the candidate gene region to 26 Mbp denoted by the last recombinant genetic marker DXRat21 at 133 Mbp to qter (the end of the long arm). In the WF background, the shaker mutation has complete penetrance, results in a stereotypic phenotype and there is a narrow window for age of disease onset; by contrast, the F2 hybrid phenotype was more varied, with a later age of onset and likely non-penetrance of the mutation. By deep RNA-sequencing, five variants were found in the candidate region; four were novel without known annotation. One of the variants caused an arginine (R) to cysteine (C) change at codon 35 of the ATPase, Ca2+ transporting, plasma membrane 3 (Atp2b3) gene encoding PMCA3 that has high expression in the cerebellum. The variant was well supported by hundreds of overlapping reads, and was found in 100% of all affected replicas and 0% of the wild-type (WT) replicas. The mutation segregated with disease in all affected animals and the amino acid change was found in an evolutionarily conserved region of PMCA3. Despite strong genetic evidence for pathogenicity, in vitro analyses of PMCA3R35C function did not show any differences to WT PMCA3. Because Atp2b3 mutation leads to congenital ataxia in humans, the identified Atp2b3 missense change in the shaker rat presents a good candidate for the shaker rat phenotype based on genetic criteria, but cannot yet be considered a definite pathogenic variant owing to lack of functional changes. Summary: The shaker rat mutant: a new model for essential tremors and ataxia characterized by Purkinje cell degeneration.
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Affiliation(s)
- Karla P Figueroa
- Department of Neurology, University of Utah, Salt Lake City, UT 84112, USA
| | - Sharan Paul
- Department of Neurology, University of Utah, Salt Lake City, UT 84112, USA
| | - Tito Calì
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Sukanya Karan
- Department of Neurology, University of Utah, Salt Lake City, UT 84112, USA
| | - Martina Frizzarin
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Darren Ames
- Bioinformatics Shared Resource, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Ginevra Zanni
- Unit of Molecular Medicine for Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Marisa Brini
- Department of Biology, University of Padova, Padova, Italy
| | - Warunee Dansithong
- Department of Neurology, University of Utah, Salt Lake City, UT 84112, USA
| | - Brett Milash
- Bioinformatics Shared Resource, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Daniel R Scoles
- Department of Neurology, University of Utah, Salt Lake City, UT 84112, USA
| | | | - Stefan M Pulst
- Department of Neurology, University of Utah, Salt Lake City, UT 84112, USA
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31
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De Mario A, Castellani A, Peggion C, Massimino ML, Lim D, Hill AF, Sorgato MC, Bertoli A. The prion protein constitutively controls neuronal store-operated Ca(2+) entry through Fyn kinase. Front Cell Neurosci 2015; 9:416. [PMID: 26578881 PMCID: PMC4623396 DOI: 10.3389/fncel.2015.00416] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/02/2015] [Indexed: 11/23/2022] Open
Abstract
The prion protein (PrPC) is a cell surface glycoprotein mainly expressed in neurons, whose misfolded isoforms generate the prion responsible for incurable neurodegenerative disorders. Whereas PrPC involvement in prion propagation is well established, PrPC physiological function is still enigmatic despite suggestions that it could act in cell signal transduction by modulating phosphorylation cascades and Ca2+ homeostasis. Because PrPC binds neurotoxic protein aggregates with high-affinity, it has also been proposed that PrPC acts as receptor for amyloid-β (Aβ) oligomers associated with Alzheimer’s disease (AD), and that PrPC-Aβ binding mediates AD-related synaptic dysfunctions following activation of the tyrosine kinase Fyn. Here, use of gene-encoded Ca2+ probes targeting different cell domains in primary cerebellar granule neurons (CGN) expressing, or not, PrPC, allowed us to investigate whether PrPC regulates store-operated Ca2+ entry (SOCE) and the implication of Fyn in this control. Our findings show that PrPC attenuates SOCE, and Ca2+ accumulation in the cytosol and mitochondria, by constitutively restraining Fyn activation and tyrosine phosphorylation of STIM1, a key molecular component of SOCE. This data establishes the existence of a PrPC-Fyn-SOCE triad in neurons. We also demonstrate that treating cerebellar granule and cortical neurons with soluble Aβ(1–42) oligomers abrogates the control of PrPC over Fyn and SOCE, suggesting a PrPC-dependent mechanizm for Aβ-induced neuronal Ca2+ dyshomeostasis.
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Affiliation(s)
- Agnese De Mario
- Department of Biomedical Science, University of Padova Padova, Italy
| | - Angela Castellani
- Department of Biomedical Science, University of Padova Padova, Italy
| | - Caterina Peggion
- Department of Biomedical Science, University of Padova Padova, Italy
| | | | - Dmitry Lim
- Department of Pharmaceutical Science, University of Piemonte Orientale Novara, Italy
| | - Andrew F Hill
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University Melbourne, VIC, Australia
| | - M Catia Sorgato
- Department of Biomedical Science, University of Padova Padova, Italy ; CNR Neuroscience Institute, University of Padova Padova, Italy
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Calì T, Ottolini D, Soriano ME, Brini M. A new split-GFP-based probe reveals DJ-1 translocation into the mitochondrial matrix to sustain ATP synthesis upon nutrient deprivation. Hum Mol Genet 2014; 24:1045-60. [PMID: 25305074 DOI: 10.1093/hmg/ddu519] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The Parkinson's disease-related protein DJ-1 has a role in the protection against oxidative stress and maintenance of mitochondria structure. Whether this action depends on its localization and activity within the mitochondria is not clear. Here we develop an approach to resolve intra-mitochondrial distribution of DJ-1 and monitor its translocation under specific conditions. By a new split-green fluorescent protein (GFP)-based tool, we can observe that a small DJ-1 fraction is located within the mitochondrial matrix and that it consistently increases upon nutrient depletion. We also find that the targeting of DJ-1 to the mitochondrial matrix enhances mitochondrial and cytosolic adenosine triphosphate levels. Intriguingly, DJ-1 pathogenic mutants fail to improve bioenergetics and translocate within the mitochondrial matrix, suggesting that the DJ-1 protective role requires both these actions. By this new split-GFP-based tool, we can resolve mitochondrial compartmentalization of proteins which are not constitutively resident in mitochondria but translocate to them in response to specific stimuli.
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Affiliation(s)
- Tito Calì
- Department of Biology, University of Padova, Via U. Bassi, 58/b, 35131 Padova, Italy
| | - Denis Ottolini
- Department of Biology, University of Padova, Via U. Bassi, 58/b, 35131 Padova, Italy
| | - Maria Eugenia Soriano
- Department of Biology, University of Padova, Via U. Bassi, 58/b, 35131 Padova, Italy
| | - Marisa Brini
- Department of Biology, University of Padova, Via U. Bassi, 58/b, 35131 Padova, Italy
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