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Petersen ED, Lapan AP, Castellanos Franco EA, Fillion AJ, Crespo EL, Lambert GG, Grady CJ, Zanca AT, Orcutt R, Hochgeschwender U, Shaner NC, Gilad AA. Bioluminescent Genetically Encoded Glutamate Indicators for Molecular Imaging of Neuronal Activity. ACS Synth Biol 2023; 12:2301-2309. [PMID: 37450884 PMCID: PMC10443529 DOI: 10.1021/acssynbio.2c00687] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Indexed: 07/18/2023]
Abstract
Genetically encoded optical sensors and advancements in microscopy instrumentation and techniques have revolutionized the scientific toolbox available for probing complex biological processes such as release of specific neurotransmitters. Most genetically encoded optical sensors currently used are based on fluorescence and have been highly successful tools for single-cell imaging in superficial brain regions. However, there remains a need to develop new tools for reporting neuronal activity in vivo within deeper structures without the need for hardware such as lenses or fibers to be implanted within the brain. Our approach to this problem is to replace the fluorescent elements of the existing biosensors with bioluminescent elements. This eliminates the need of external light sources to illuminate the sensor, thus allowing deeper brain regions to be imaged noninvasively. Here, we report the development of the first genetically encoded neurotransmitter indicators based on bioluminescent light emission. These probes were optimized by high-throughput screening of linker libraries. The selected probes exhibit robust changes in light output in response to the extracellular presence of the excitatory neurotransmitter glutamate. We expect this new approach to neurotransmitter indicator design to enable the engineering of specific bioluminescent probes for multiple additional neurotransmitters in the future, ultimately allowing neuroscientists to monitor activity associated with a specific neurotransmitter as it relates to behavior in a variety of neuronal and psychiatric disorders, among many other applications.
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Affiliation(s)
- Eric D. Petersen
- Department
of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, United States
- College
of Medicine, Central Michigan University, Mount Pleasant, Michigan 48859, United States
| | - Alexandra P. Lapan
- Department
of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, United States
| | | | - Adam J. Fillion
- Department
of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, United States
| | - Emmanuel L. Crespo
- College
of Medicine, Central Michigan University, Mount Pleasant, Michigan 48859, United States
| | - Gerard G. Lambert
- Department
of Neurosciences, University of California
San Diego School of Medicine, La Jolla, California 92093, United States
| | - Connor J. Grady
- Department
of Biomedical Engineering, Michigan State
University, East Lansing, Michigan 48824, United States
| | - Albertina T. Zanca
- Department
of Neurosciences, University of California
San Diego School of Medicine, La Jolla, California 92093, United States
| | - Richard Orcutt
- Department
of Neurosciences, University of California
San Diego School of Medicine, La Jolla, California 92093, United States
| | - Ute Hochgeschwender
- College
of Medicine, Central Michigan University, Mount Pleasant, Michigan 48859, United States
| | - Nathan C. Shaner
- Department
of Neurosciences, University of California
San Diego School of Medicine, La Jolla, California 92093, United States
| | - Assaf A. Gilad
- Department
of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan 48824, United States
- Department
of Radiology, Michigan State University, East Lansing, Michigan 48824, United States
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2
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Filadi R, Greotti E. The yin and yang of mitochondrial Ca 2+ signaling in cell physiology and pathology. Cell Calcium 2020; 93:102321. [PMID: 33310302 DOI: 10.1016/j.ceca.2020.102321] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/16/2020] [Accepted: 11/16/2020] [Indexed: 12/26/2022]
Abstract
Mitochondria are autonomous and dynamic cellular organelles orchestrating a diverse range of cellular activities. Numerous cell-signaling pathways target these organelles and Ca2+ is one of the most significant. Mitochondria are able to rapidly and transiently take up Ca2+, thanks to the mitochondrial Ca2+ uniporter complex, as well as to extrude it through the Na+/Ca2+ and H+/Ca2+ exchangers. The transient accumulation of Ca2+ in the mitochondrial matrix impacts on mitochondrial functions and cell pathophysiology. Here we summarize the role of mitochondrial Ca2+ signaling in both physiological (yang) and pathological (yin) processes and the methods that can be used to investigate mitochondrial Ca2+ homeostasis. As an example of the pivotal role of mitochondria in pathology, we described the state of the art of mitochondrial Ca2+ alterations in different pathological conditions, with a special focus on Alzheimer's disease.
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Affiliation(s)
- Riccardo Filadi
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy; Department of Biomedical Sciences, University of Padua, 35131, Padua, Italy.
| | - Elisa Greotti
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy; Department of Biomedical Sciences, University of Padua, 35131, Padua, Italy.
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3
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Liviero F, Scarpa MC, De Stefani D, Folino F, Campisi M, Mason P, Iliceto S, Pavanello S, Maestrelli P. Modulation of TRPV-1 by prostaglandin-E 2 and bradykinin changes cough sensitivity and autonomic regulation of cardiac rhythm in healthy subjects. Sci Rep 2020; 10:15163. [PMID: 32938990 PMCID: PMC7494872 DOI: 10.1038/s41598-020-72062-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 08/25/2020] [Indexed: 11/17/2022] Open
Abstract
A neurogenic pathway, involving airway TRPV-1, has been implicated in acute cardiovascular events occurring after peaks of air pollution. We tested whether inhaled prostaglandin-E2 (PGE2) and bradykinin (BK) regulate TRPV-1 activity in vivo by changing cough response to capsaicin (CPS) and affecting heart rate variability (HRV), while also taking into account the influence of TRPV-1 polymorphisms (SNPs). Moreover, we assessed the molecular mechanism of TRPV-1 modulation in vitro. Seventeen healthy volunteers inhaled 100 μg PGE2, 200 μg BK or diluent in a randomized double-blind fashion. Subsequently, the response to CPS was assessed by cough challenge and the sympathetic activity by HRV, expressed by low (nLF) and high (nHF) normalized frequency components, as well as nLF/nHF ratio. Intracellular [Ca2+] was measured in HeLa cells, transfected with wild-type TRPV-1, pre-treated with increasing doses of PGE2, BK or diesel exhaust particulate (DEP), after CPS stimulation. Six functional TRPV-1 SNPs were characterized in DNA from each subject. Inhalation of PGE2 and BK was associated with significant increases in cough response induced by 30 μM of CPS (cough number after PGE2 = 4.20 ± 0.42; p < 0.001, and after BK = 3.64 ± 0.37; p < 0.01), compared to diluent (2.77 ± 0.29) and in sympathetic activity (nLF/nHF ratio after PGE2 = 6.1; p < 0.01, and after BK = 4.2; p < 0.05), compared to diluent (2.5–3.3). No influence of SNPs was observed on autonomic regulation and cough sensitivity. Unlike PGE2 and BK, DEP directly activated TRPV-1. Inhalation of PGE2 and BK sensitizes TRPV-1 and is associated with autonomic dysregulation of cardiac rhythm in healthy subjects.
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Affiliation(s)
- Filippo Liviero
- Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, Via Giustiniani 2, 35128, Padua, Italy
| | - Maria Cristina Scarpa
- Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, Via Giustiniani 2, 35128, Padua, Italy
| | - Diego De Stefani
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Franco Folino
- Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, Via Giustiniani 2, 35128, Padua, Italy
| | - Manuela Campisi
- Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, Via Giustiniani 2, 35128, Padua, Italy
| | - Paola Mason
- Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, Via Giustiniani 2, 35128, Padua, Italy
| | - Sabino Iliceto
- Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, Via Giustiniani 2, 35128, Padua, Italy
| | - Sofia Pavanello
- Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, Via Giustiniani 2, 35128, Padua, Italy.
| | - Piero Maestrelli
- Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, Via Giustiniani 2, 35128, Padua, Italy
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4
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Paggio A, Checchetto V, Campo A, Menabò R, Di Marco G, Di Lisa F, Szabo I, Rizzuto R, De Stefani D. Identification of an ATP-sensitive potassium channel in mitochondria. Nature 2019; 572:609-613. [PMID: 31435016 PMCID: PMC6726485 DOI: 10.1038/s41586-019-1498-3] [Citation(s) in RCA: 173] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 07/25/2019] [Indexed: 11/09/2022]
Abstract
Mitochondria provide chemical energy for endoergonic reactions in the form of ATP, and their activity must meet cellular energy requirements, but the mechanisms that link organelle performance to ATP levels are poorly understood. Here we confirm the existence of a protein complex localized in mitochondria that mediates ATP-dependent potassium currents (that is, mitoKATP). We show that-similar to their plasma membrane counterparts-mitoKATP channels are composed of pore-forming and ATP-binding subunits, which we term MITOK and MITOSUR, respectively. In vitro reconstitution of MITOK together with MITOSUR recapitulates the main properties of mitoKATP. Overexpression of MITOK triggers marked organelle swelling, whereas the genetic ablation of this subunit causes instability in the mitochondrial membrane potential, widening of the intracristal space and decreased oxidative phosphorylation. In a mouse model, the loss of MITOK suppresses the cardioprotection that is elicited by pharmacological preconditioning induced by diazoxide. Our results indicate that mitoKATP channels respond to the cellular energetic status by regulating organelle volume and function, and thereby have a key role in mitochondrial physiology and potential effects on several pathological processes.
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Affiliation(s)
- Angela Paggio
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Antonio Campo
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | | | - Giulia Di Marco
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Fabio Di Lisa
- Department of Biomedical Sciences, University of Padova, Padova, Italy.,CNR Institute of Neuroscience, Padova, Italy
| | - Ildiko Szabo
- Department of Biology, University of Padova, Padova, Italy.,CNR Institute of Neuroscience, Padova, Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padova, Padova, Italy.
| | - Diego De Stefani
- Department of Biomedical Sciences, University of Padova, Padova, Italy.
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5
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Carnevale D, Facchinello N, Iodice D, Bizzotto D, Perrotta M, De Stefani D, Pallante F, Carnevale L, Ricciardi F, Cifelli G, Da Ros F, Casaburo M, Fardella S, Bonaldo P, Innocenzi G, Rizzuto R, Braghetta P, Lembo G, Bressan GM. Loss of EMILIN-1 Enhances Arteriolar Myogenic Tone Through TGF-β (Transforming Growth Factor-β)–Dependent Transactivation of EGFR (Epidermal Growth Factor Receptor) and Is Relevant for Hypertension in Mice and Humans. Arterioscler Thromb Vasc Biol 2018; 38:2484-2497. [DOI: 10.1161/atvbaha.118.311115] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Daniela Carnevale
- From the Department of Molecular Medicine, Sapienza University of Rome, Italy (D.C., M.P., G.L.)
- Department of Angiocardioneurology and Translational Medicine (D.C., D.I., F.P., L.C., G.C., M.C., S.F., G.L.), IRCCS Neuromed, Pozzilli, Italy
| | - Nicola Facchinello
- Department of Molecular Medicine (N.F., D.B., F.D.R., P. Bonaldo, P. Braghetta, G.M.B.), University of Padova, Italy
| | - Daniele Iodice
- Department of Angiocardioneurology and Translational Medicine (D.C., D.I., F.P., L.C., G.C., M.C., S.F., G.L.), IRCCS Neuromed, Pozzilli, Italy
| | - Dario Bizzotto
- Department of Molecular Medicine (N.F., D.B., F.D.R., P. Bonaldo, P. Braghetta, G.M.B.), University of Padova, Italy
| | - Marialuisa Perrotta
- From the Department of Molecular Medicine, Sapienza University of Rome, Italy (D.C., M.P., G.L.)
| | - Diego De Stefani
- Department of Biomedical Sciences (D.D.S., R.R.), University of Padova, Italy
| | - Fabio Pallante
- Department of Angiocardioneurology and Translational Medicine (D.C., D.I., F.P., L.C., G.C., M.C., S.F., G.L.), IRCCS Neuromed, Pozzilli, Italy
| | - Lorenzo Carnevale
- Department of Angiocardioneurology and Translational Medicine (D.C., D.I., F.P., L.C., G.C., M.C., S.F., G.L.), IRCCS Neuromed, Pozzilli, Italy
| | - Franco Ricciardi
- Department of Neurosurgery (F.R., G.I.), IRCCS Neuromed, Pozzilli, Italy
| | - Giuseppe Cifelli
- Department of Angiocardioneurology and Translational Medicine (D.C., D.I., F.P., L.C., G.C., M.C., S.F., G.L.), IRCCS Neuromed, Pozzilli, Italy
| | - Francesco Da Ros
- Department of Molecular Medicine (N.F., D.B., F.D.R., P. Bonaldo, P. Braghetta, G.M.B.), University of Padova, Italy
| | - Manuel Casaburo
- Department of Angiocardioneurology and Translational Medicine (D.C., D.I., F.P., L.C., G.C., M.C., S.F., G.L.), IRCCS Neuromed, Pozzilli, Italy
| | - Stefania Fardella
- Department of Angiocardioneurology and Translational Medicine (D.C., D.I., F.P., L.C., G.C., M.C., S.F., G.L.), IRCCS Neuromed, Pozzilli, Italy
| | - Paolo Bonaldo
- Department of Molecular Medicine (N.F., D.B., F.D.R., P. Bonaldo, P. Braghetta, G.M.B.), University of Padova, Italy
| | | | - Rosario Rizzuto
- Department of Biomedical Sciences (D.D.S., R.R.), University of Padova, Italy
| | - Paola Braghetta
- Department of Molecular Medicine (N.F., D.B., F.D.R., P. Bonaldo, P. Braghetta, G.M.B.), University of Padova, Italy
| | - Giuseppe Lembo
- From the Department of Molecular Medicine, Sapienza University of Rome, Italy (D.C., M.P., G.L.)
- Department of Angiocardioneurology and Translational Medicine (D.C., D.I., F.P., L.C., G.C., M.C., S.F., G.L.), IRCCS Neuromed, Pozzilli, Italy
| | - Giorgio M. Bressan
- Department of Molecular Medicine (N.F., D.B., F.D.R., P. Bonaldo, P. Braghetta, G.M.B.), University of Padova, Italy
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6
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Patron M, Granatiero V, Espino J, Rizzuto R, De Stefani D. MICU3 is a tissue-specific enhancer of mitochondrial calcium uptake. Cell Death Differ 2018; 26:179-195. [PMID: 29725115 DOI: 10.1038/s41418-018-0113-8] [Citation(s) in RCA: 147] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 03/05/2018] [Accepted: 03/19/2018] [Indexed: 01/14/2023] Open
Abstract
The versatility and universality of Ca2+ as intracellular messenger is guaranteed by the compartmentalization of changes in [Ca2+]. In this context, mitochondrial Ca2+ plays a central role, by regulating both specific organelle functions and global cellular events. This versatility is also guaranteed by a cell type-specific Ca2+ signaling toolkit controlling specific cellular functions. Accordingly, mitochondrial Ca2+ uptake is mediated by a multimolecular structure, the MCU complex, which differs among various tissues. Its activity is indeed controlled by different components that cooperate to modulate specific channeling properties. We here investigate the role of MICU3, an EF-hand containing protein expressed at high levels, especially in brain. We show that MICU3 forms a disulfide bond-mediated dimer with MICU1, but not with MICU2, and it acts as enhancer of MCU-dependent mitochondrial Ca2+ uptake. Silencing of MICU3 in primary cortical neurons impairs Ca2+ signals elicited by synaptic activity, thus suggesting a specific role in regulating neuronal function.
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Affiliation(s)
- Maria Patron
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58B, 35131, Padova, Italy.,Max Planck Institute for Biology and Aging, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Veronica Granatiero
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58B, 35131, Padova, Italy.,Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, 401 East 61st Street, New York, NY, 10065, United States
| | - Javier Espino
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58B, 35131, Padova, Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58B, 35131, Padova, Italy.
| | - Diego De Stefani
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58B, 35131, Padova, Italy.
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7
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Tosatto A, Rizzuto R, Mammucari C. Ca 2+ Measurements in Mammalian Cells with Aequorin-based Probes. Bio Protoc 2017; 7:e2155. [PMID: 28382319 DOI: 10.21769/bioprotoc.2155] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Aequorin is a Ca2+ sensitive photoprotein suitable to measure intracellular Ca2+ transients in mammalian cells. Thanks to recombinant cDNAs expression, aequorin can be specifically targeted to various subcellular compartments, thus allowing an accurate measurement of Ca2+ uptake and release of different intracellular organelles. Here, we describe how to use this probe to measure cytosolic Ca2+ levels and mitochondrial Ca2+ uptake in mammalian cells.
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Affiliation(s)
- Anna Tosatto
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padua, Padua, Italy
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8
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Doghman-Bouguerra M, Granatiero V, Sbiera S, Sbiera I, Lacas-Gervais S, Brau F, Fassnacht M, Rizzuto R, Lalli E. FATE1 antagonizes calcium- and drug-induced apoptosis by uncoupling ER and mitochondria. EMBO Rep 2016; 17:1264-80. [PMID: 27402544 PMCID: PMC5007562 DOI: 10.15252/embr.201541504] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 06/10/2016] [Accepted: 06/16/2016] [Indexed: 11/09/2022] Open
Abstract
Several stimuli induce programmed cell death by increasing Ca(2+) transfer from the endoplasmic reticulum (ER) to mitochondria. Perturbation of this process has a special relevance in pathologies as cancer and neurodegenerative disorders. Mitochondrial Ca(2+) uptake mainly takes place in correspondence of mitochondria-associated ER membranes (MAM), specialized contact sites between the two organelles. Here, we show the important role of FATE1, a cancer-testis antigen, in the regulation of ER-mitochondria distance and Ca(2+) uptake by mitochondria. FATE1 is localized at the interface between ER and mitochondria, fractionating into MAM FATE1 expression in adrenocortical carcinoma (ACC) cells under the control of the transcription factor SF-1 decreases ER-mitochondria contact and mitochondrial Ca(2+) uptake, while its knockdown has an opposite effect. FATE1 also decreases sensitivity to mitochondrial Ca(2+)-dependent pro-apoptotic stimuli and to the chemotherapeutic drug mitotane. In patients with ACC, FATE1 expression in their tumor is inversely correlated with their overall survival. These results show that the ER-mitochondria uncoupling activity of FATE1 is harnessed by cancer cells to escape apoptotic death and resist the action of chemotherapeutic drugs.
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Affiliation(s)
- Mabrouka Doghman-Bouguerra
- Institut de Pharmacologie Moléculaire et Cellulaire CNRS UMR 7275 Sophia Antipolis, Valbonne, France NEOGENEX CNRS International Associated Laboratory, Valbonne, France University of Nice - Sophia Antipolis, Valbonne, France
| | - Veronica Granatiero
- Department of Biomedical Sciences, University of Padova, Padova, Italy CNR Neuroscience Institute, Padova, Italy
| | - Silviu Sbiera
- Department of Internal Medicine I - Endocrine Unit, University Hospital University of Würzburg, Würzburg, Germany
| | - Iuliu Sbiera
- Department of Internal Medicine I - Endocrine Unit, University Hospital University of Würzburg, Würzburg, Germany
| | | | - Frédéric Brau
- Institut de Pharmacologie Moléculaire et Cellulaire CNRS UMR 7275 Sophia Antipolis, Valbonne, France University of Nice - Sophia Antipolis, Valbonne, France
| | - Martin Fassnacht
- Comprehensive Cancer Center Mainfranken, University of Würzburg, Würzburg, Germany
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padova, Padova, Italy CNR Neuroscience Institute, Padova, Italy
| | - Enzo Lalli
- Institut de Pharmacologie Moléculaire et Cellulaire CNRS UMR 7275 Sophia Antipolis, Valbonne, France NEOGENEX CNRS International Associated Laboratory, Valbonne, France University of Nice - Sophia Antipolis, Valbonne, France
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9
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Reduced mitochondrial Ca(2+) transients stimulate autophagy in human fibroblasts carrying the 13514A>G mutation of the ND5 subunit of NADH dehydrogenase. Cell Death Differ 2015. [PMID: 26206091 DOI: 10.1038/cdd.2015.84] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Mitochondrial disorders are a group of pathologies characterized by impairment of mitochondrial function mainly due to defects of the respiratory chain and consequent organellar energetics. This affects organs and tissues that require an efficient energy supply, such as brain and skeletal muscle. They are caused by mutations in both nuclear- and mitochondrial DNA (mtDNA)-encoded genes and their clinical manifestations show a great heterogeneity in terms of age of onset and severity, suggesting that patient-specific features are key determinants of the pathogenic process. In order to correlate the genetic defect to the clinical phenotype, we used a cell culture model consisting of fibroblasts derived from patients with different mutations in the mtDNA-encoded ND5 complex I subunit and with different severities of the illness. Interestingly, we found that cells from patients with the 13514A>G mutation, who manifested a relatively late onset and slower progression of the disease, display an increased autophagic flux when compared with fibroblasts from other patients or healthy donors. We characterized their mitochondrial phenotype by investigating organelle turnover, morphology, membrane potential and Ca(2+) homeostasis, demonstrating that mitochondrial quality control through mitophagy is upregulated in 13514A>G cells. This is due to a specific downregulation of mitochondrial Ca(2+) uptake that causes the stimulation of the autophagic machinery through the AMPK signaling axis. Genetic and pharmacological manipulation of mitochondrial Ca(2+) homeostasis can revert this phenotype, but concurrently decreases cell viability. This indicates that the higher mitochondrial turnover in complex I deficient cells with this specific mutation is a pro-survival compensatory mechanism that could contribute to the mild clinical phenotype of this patient.
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10
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Tisi R, Martegani E, Brandão RL. Monitoring yeast intracellular Ca2+ levels using an in vivo bioluminescence assay. Cold Spring Harb Protoc 2015; 2015:210-3. [PMID: 25646494 DOI: 10.1101/pdb.prot076851] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This protocol describes the use of the jellyfish Aequorea victoria aequorin protein to measure Ca(2+) levels in living yeast cells. All yeast strains to be analyzed must express the A. victoria apoprotein of the aequorin calcium biosensor, to be reconstituted into fully active aequorin by association with its cofactor, coelenterazine, which cannot be synthesized by yeast itself. The simplest way to achieve reconstitution is to transform yeast cells with a vector driving apoaequorin expression, and then supply commercially available coelenterazine cofactor in the medium. Coelenterazine is a hydrophobic molecule and is able to permeate yeast cells.
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Affiliation(s)
- Renata Tisi
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milan, Italy
| | - Enzo Martegani
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milan, Italy
| | - Rogelio L Brandão
- Laboratório de Bioquímica e Biotecnologia de Leveduras, Núcleo de Pesquisas em Ciências Biológicas, Escola de Farmácia, Universidade Federal de Ouro Preto, Campus do Morro do Cruzeiro, 35.400-000 Ouro Preto, Minas Gerais, Brazil
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11
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Granatiero V, Patron M, Tosatto A, Merli G, Rizzuto R. The use of aequorin and its variants for Ca2+ measurements. Cold Spring Harb Protoc 2014; 2014:9-16. [PMID: 24371311 DOI: 10.1101/pdb.top066118] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Ca(2+)-sensitive photoproteins are ideal agents for measuring the Ca(2+) concentration ([Ca(2+)]) in intracellular organelles because they can be modified to include specific targeting sequences. Aequorin was the first Ca(2+)-sensitive photoprotein probe used to measure the [Ca(2+)] inside specific intracellular organelles in intact cells. Aequorin is a 22-kDa protein produced by the jellyfish Aequorea victoria. On the binding of Ca(2+) to three high-affinity sites in aequorin, an irreversible reaction occurs in which the prosthetic group is released and a photon is emitted. Aequorin has become widely used for intracellular Ca(2+) measurements because it offers many advantages: For example, it can be targeted with precision, functions over a wide range of [Ca(2+)], and shows low buffering capacity. In this article we describe the main characteristics of the aequorin probe and review the reasons why it is widely used to measure intracellular [Ca(2+)].
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Affiliation(s)
- Veronica Granatiero
- Department of Biomedical Sciences, University of Padua and CNR Neuroscience Institute, 35131 Padua, Italy
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