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Characterization of the ER-Targeted Low Affinity Ca(2+) Probe D4ER. SENSORS 2016; 16:s16091419. [PMID: 27598166 PMCID: PMC5038697 DOI: 10.3390/s16091419] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 08/26/2016] [Accepted: 08/30/2016] [Indexed: 12/17/2022]
Abstract
Calcium ion (Ca2+) is a ubiquitous intracellular messenger and changes in its concentration impact on nearly every aspect of cell life. Endoplasmic reticulum (ER) represents the major intracellular Ca2+ store and the free Ca2+ concentration ([Ca2+]) within its lumen ([Ca2+]ER) can reach levels higher than 1 mM. Several genetically-encoded ER-targeted Ca2+ sensors have been developed over the last years. However, most of them are non-ratiometric and, thus, their signal is difficult to calibrate in live cells and is affected by shifts in the focal plane and artifactual movements of the sample. On the other hand, existing ratiometric Ca2+ probes are plagued by different drawbacks, such as a double dissociation constant (Kd) for Ca2+, low dynamic range, and an affinity for the cation that is too high for the levels of [Ca2+] in the ER lumen. Here, we report the characterization of a recently generated ER-targeted, Förster resonance energy transfer (FRET)-based, Cameleon probe, named D4ER, characterized by suitable Ca2+ affinity and dynamic range for monitoring [Ca2+] variations within the ER. As an example, resting [Ca2+]ER have been evaluated in a known paradigm of altered ER Ca2+ homeostasis, i.e., in cells expressing a mutated form of the familial Alzheimer’s Disease-linked protein Presenilin 2 (PS2). The lower Ca2+ affinity of the D4ER probe, compared to that of the previously generated D1ER, allowed the detection of a conspicuous, more clear-cut, reduction in ER Ca2+ content in cells expressing mutated PS2, compared to controls.
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152
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Stoica R, Paillusson S, Gomez-Suaga P, Mitchell JC, Lau DH, Gray EH, Sancho RM, Vizcay-Barrena G, De Vos KJ, Shaw CE, Hanger DP, Noble W, Miller CC. ALS/FTD-associated FUS activates GSK-3β to disrupt the VAPB-PTPIP51 interaction and ER-mitochondria associations. EMBO Rep 2016; 17:1326-42. [PMID: 27418313 PMCID: PMC5007559 DOI: 10.15252/embr.201541726] [Citation(s) in RCA: 192] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 05/06/2016] [Accepted: 06/13/2016] [Indexed: 12/12/2022] Open
Abstract
Defective FUS metabolism is strongly associated with amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD), but the mechanisms linking FUS to disease are not properly understood. However, many of the functions disrupted in ALS/FTD are regulated by signalling between the endoplasmic reticulum (ER) and mitochondria. This signalling is facilitated by close physical associations between the two organelles that are mediated by binding of the integral ER protein VAPB to the outer mitochondrial membrane protein PTPIP51, which act as molecular scaffolds to tether the two organelles. Here, we show that FUS disrupts the VAPB-PTPIP51 interaction and ER-mitochondria associations. These disruptions are accompanied by perturbation of Ca(2+) uptake by mitochondria following its release from ER stores, which is a physiological read-out of ER-mitochondria contacts. We also demonstrate that mitochondrial ATP production is impaired in FUS-expressing cells; mitochondrial ATP production is linked to Ca(2+) levels. Finally, we demonstrate that the FUS-induced reductions to ER-mitochondria associations and are linked to activation of glycogen synthase kinase-3β (GSK-3β), a kinase already strongly associated with ALS/FTD.
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Affiliation(s)
- Radu Stoica
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
| | - Sébastien Paillusson
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
| | - Patricia Gomez-Suaga
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
| | - Jacqueline C Mitchell
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
| | - Dawn Hw Lau
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
| | - Emma H Gray
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
| | - Rosa M Sancho
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
| | | | - Kurt J De Vos
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
| | - Christopher E Shaw
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
| | - Diane P Hanger
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
| | - Wendy Noble
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
| | - Christopher Cj Miller
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK
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153
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Astroglial calcium signalling in Alzheimer's disease. Biochem Biophys Res Commun 2016; 483:1005-1012. [PMID: 27545605 DOI: 10.1016/j.bbrc.2016.08.088] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 08/15/2016] [Indexed: 12/14/2022]
Abstract
Neuroglial contribution to Alzheimer's disease (AD) is pathologically relevant and highly heterogeneous. Reactive astrogliosis and activation of microglia contribute to neuroinflammation, whereas astroglial and oligodendroglial atrophy affect synaptic transmission and underlie the overall disruption of the central nervous system (CNS) connectome. Astroglial function is tightly integrated with the intracellular ionic signalling mediated by complex dynamics of cytosolic concentrations of free Ca2+ and Na+. Astroglial ionic signalling is mediated by plasmalemmal ion channels, mainly associated with ionotropic receptors, pumps and solute carrier transporters, and by intracellular organelles comprised of the endoplasmic reticulum and mitochondria. The relative contribution of these molecular cascades/organelles can be plastically remodelled in development and under environmental stress. In AD astroglial Ca2+ signalling undergoes substantial reorganisation due to an abnormal regulation of expression of Ca2+ handling molecular cascades.
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154
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Calvo-Rodríguez M, García-Durillo M, Villalobos C, Núñez L. In vitro aging promotes endoplasmic reticulum (ER)-mitochondria Ca 2+ cross talk and loss of store-operated Ca 2+ entry (SOCE) in rat hippocampal neurons. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2637-2649. [PMID: 27503411 DOI: 10.1016/j.bbamcr.2016.08.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 07/27/2016] [Accepted: 08/04/2016] [Indexed: 12/11/2022]
Abstract
Aging is associated to cognitive decline and susceptibility to neuron death, two processes related recently to subcellular Ca2+ homeostasis. Memory storage relies on mushroom spines stability that depends on store-operated Ca2+ entry (SOCE). In addition, Ca2+ transfer from endoplasmic reticulum (ER) to mitochondria sustains energy production but mitochondrial Ca2+ overload promotes apoptosis. We have addressed whether SOCE and ER-mitochondria Ca2+ transfer are influenced by culture time in long-term cultures of rat hippocampal neurons, a model of neuronal aging. We found that short-term cultured neurons show large SOCE, low Ca2+ store content and no functional coupling between ER and mitochondria. In contrast, in long-term cultures reflecting aging neurons, SOCE is essentially lost, Stim1 and Orai1 are downregulated, Ca2+ stores become overloaded, Ca2+ release is enhanced, expression of the mitochondrial Ca2+ uniporter (MCU) increases and most Ca2+ released from the ER is transferred to mitochondria. These results suggest that neuronal aging is associated to increased ER-mitochondrial cross talking and loss of SOCE. This subcellular Ca2+ remodeling might contribute to cognitive decline and susceptibility to neuron cell death in the elderly.
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Affiliation(s)
- María Calvo-Rodríguez
- Instituto de Biología y Genética Molecular (IBGM), Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain
| | - Mónica García-Durillo
- Instituto de Biología y Genética Molecular (IBGM), Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain
| | - Carlos Villalobos
- Instituto de Biología y Genética Molecular (IBGM), Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain.
| | - Lucía Núñez
- Instituto de Biología y Genética Molecular (IBGM), Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain; Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Valladolid, Spain
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155
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Kumar A, Sivanandam TM, Thakur MK. Presenilin 2 overexpression is associated with apoptosis in Neuro2a cells. Transl Neurosci 2016; 7:71-75. [PMID: 28123824 PMCID: PMC5234515 DOI: 10.1515/tnsci-2016-0011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 06/09/2016] [Indexed: 01/21/2023] Open
Abstract
Presenilin 1 (PS1) and PS2 are evolutionarily conserved transmembrane proteins of the aspartyl protease family. Initially, they were reported to be associated with the early onset of familial, early-onset Alzheimer’s disease. PS1 has been implicated in several crucial brain functions including developmental processes, synaptic plasticity, and processing of various molecules, while PS2 has been poorly studied and is considered to be a compensatory partner of PS1. Certain controversial reports have suggested that PS2 has a role in apoptosis, though the underlying mechanism is not clear. To ascertain the role of PS2 in apoptosis, mouse neuroblastoma cells (Neuro2a) were transfected with a cDNA construct encoding full length mouse PS2 and analyzed for viability, expression of PS1, PS2, Bax and p53, Bax protein, and status of chromatin condensation. Our results showed reduced viability, condensed chromatin and higher expression of Bax at mRNA and protein levels, but no change in the expression of p53 and PS1 in PS2-overexpressing Neuro2a cells. Thus, it is evident that PS2, independent of PS1, is associated with apoptosis via a Bax-mediated pathway. These findings might help in the understanding of the involvement of PS2 in apoptosis and its associated brain disorders.
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Affiliation(s)
- Ashish Kumar
- Laboratory of Biochemistry and Molecular Biology, Brain Research Centre, Department of Zoology, Banaras Hindu University, Varanasi 221 005, India; Centre for Genomics, Jiwaji University, Gwalior 474 011, India
| | - T M Sivanandam
- Laboratory of Biochemistry and Molecular Biology, Brain Research Centre, Department of Zoology, Banaras Hindu University, Varanasi 221 005, India
| | - M K Thakur
- Laboratory of Biochemistry and Molecular Biology, Brain Research Centre, Department of Zoology, Banaras Hindu University, Varanasi 221 005, India
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156
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Suzuki J, Kanemaru K, Iino M. Genetically Encoded Fluorescent Indicators for Organellar Calcium Imaging. Biophys J 2016; 111:1119-1131. [PMID: 27477268 DOI: 10.1016/j.bpj.2016.04.054] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 03/30/2016] [Accepted: 04/01/2016] [Indexed: 12/14/2022] Open
Abstract
Optical Ca(2+) indicators are powerful tools for investigating intracellular Ca(2+) signals in living cells. Although a variety of Ca(2+) indicators have been developed, deciphering the physiological functions and spatiotemporal dynamics of Ca(2+) in intracellular organelles remains challenging. Genetically encoded Ca(2+) indicators (GECIs) using fluorescent proteins are promising tools for organellar Ca(2+) imaging, and much effort has been devoted to their development. In this review, we first discuss the key points of organellar Ca(2+) imaging and summarize the requirements for optimal organellar Ca(2+) indicators. Then, we highlight some of the recent advances in the engineering of fluorescent GECIs targeted to specific organelles. Finally, we discuss the limitations of currently available GECIs and the requirements for advancing the research on intraorganellar Ca(2+) signaling.
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Affiliation(s)
- Junji Suzuki
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Department of Physiology, University of California San Francisco, San Francisco, California
| | - Kazunori Kanemaru
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Masamitsu Iino
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Department of Cellular and Molecular Pharmacology, Nihon University School of Medicine, Tokyo, Japan.
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157
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Agostini M, Fasolato C. When, where and how? Focus on neuronal calcium dysfunctions in Alzheimer's Disease. Cell Calcium 2016; 60:289-298. [PMID: 27451385 DOI: 10.1016/j.ceca.2016.06.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 06/27/2016] [Accepted: 06/28/2016] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD), since its characterization as a precise form of dementia with its own pathological hallmarks, has captured scientists' attention because of its complexity. The last 30 years have been filled with discoveries regarding the elusive aetiology of this disease and, thanks to advances in molecular biology and live imaging techniques, we now know that an important role is played by calcium (Ca2+). Ca2+, as ubiquitous second messenger, regulates a vast variety of cellular processes, from neuronal excitation and communication, to muscle fibre contraction and hormone secretion, with its action spanning a temporal scale that goes from microseconds to hours. It is therefore very challenging to conceive a single hypothesis that can integrate the numerous findings on this issue with those coming from the classical fields of AD research such as amyloid-beta (Aβ) and tau pathology. In this contribution, we will focus our attention on the Ca2+ hypothesis of AD, dissecting it, as much as possible, in its subcellular localization, where the Ca2+ signal meets its specificity. We will also follow the temporal evolution of the Ca2+ hypothesis, providing some of the most updated discoveries. Whenever possible, we will link the findings regarding Ca2+ dysfunction to the other players involved in AD pathogenesis, hoping to provide a crossover body of evidence, useful to amplify the knowledge that will lead towards the discovery of an effective therapy.
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Affiliation(s)
- Mario Agostini
- Department of Biomedical Sciences, University of Padua, Italy.
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158
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Giacomello M, Pellegrini L. The coming of age of the mitochondria-ER contact: a matter of thickness. Cell Death Differ 2016; 23:1417-27. [PMID: 27341186 DOI: 10.1038/cdd.2016.52] [Citation(s) in RCA: 278] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 05/02/2016] [Accepted: 05/05/2016] [Indexed: 12/12/2022] Open
Abstract
The sites of near-contact between the mitochondrion and the endoplasmic reticulum (ER) have earned a lot of attention due to their key role in the maintenance of lipid and calcium (Ca(2+)) homeostasis, in the initiation of autophagy and mitochondrial division, and in sensing metabolic shifts. At these sites, typically called MAMs (mitochondria-associated ER membranes) or MERCs (mitochondria-ER contacts), the organelles juxtapose at a distance that can range from ~10 to ~50 nm. The multifunctional role of this subcellular compartment is puzzling; further, recent studies have shown that mitochondria-ER contacts are highly plastic structures that remodel upon metabolic transitions and that their activity in controlling lipid homeostasis could be involved in Alzheimer's disease pathogenesis. This review aims at integrating the functions of this subcellular compartment to its most characterizing and unexplored structural parameter, their 'thickness': that is, the width of the cleft that separates the cytosolic face of the outer mitochondrial membrane from that of the ER. We describe and discuss the reasons why the thickness of a MERC should be considered a regulated structural parameter of the cell that defines and controls its function. Further, we propose a MERC classification that will help organize the expanding field of MERCs biology and of their role in cell physiology and human disease.
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Affiliation(s)
- M Giacomello
- Department of Biology, Università di Padova, Padua, Italy.,Venetian Institute of Molecular Medicine, Padua, Italy
| | - L Pellegrini
- Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Universitè Laval, Quebec, Québec, Canada.,Mitochondria Biology Laboratory, CRIUSMQ, Quebec, Québec, Canada
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159
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Patra M, Mahata SK, Padhan DK, Sen M. CCN6 regulates mitochondrial function. J Cell Sci 2016; 129:2841-51. [PMID: 27252383 DOI: 10.1242/jcs.186247] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 04/08/2016] [Indexed: 12/29/2022] Open
Abstract
Despite established links of CCN6, or Wnt induced signaling protein-3 (WISP3), with progressive pseudo rheumatoid dysplasia, functional characterization of CCN6 remains incomplete. In light of the documented negative correlation between accumulation of reactive oxygen species (ROS) and CCN6 expression, we investigated whether CCN6 regulates ROS accumulation through its influence on mitochondrial function. We found that CCN6 localizes to mitochondria, and depletion of CCN6 in the chondrocyte cell line C-28/I2 by using siRNA results in altered mitochondrial electron transport and respiration. Enhanced electron transport chain (ETC) activity of CCN6-depleted cells was reflected by increased mitochondrial ROS levels in association with augmented mitochondrial ATP synthesis, mitochondrial membrane potential and Ca(2+) Additionally, CCN6-depleted cells display ROS-dependent PGC1α (also known as PPARGC1A) induction, which correlates with increased mitochondrial mass and volume density, together with altered mitochondrial morphology. Interestingly, transcription factor Nrf2 (also known as NFE2L2) repressed CCN6 expression. Taken together, our results suggest that CCN6 acts as a molecular brake, which is appropriately balanced by Nrf2, in regulating mitochondrial function.
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Affiliation(s)
- Milan Patra
- Cancer Biology and Inflammatory Disorder Division, CSIR-Indian institute of Chemical Biology, 4-Raja S.C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Sushil K Mahata
- Metabolic Physiology and Ultrastructure Biology Laboratory, University of California, San Diego, CA 92093-0732, USA Veterans Affairs San Diego Healthcare System, San Diego, CA 92161, USA
| | - Deepesh K Padhan
- Cancer Biology and Inflammatory Disorder Division, CSIR-Indian institute of Chemical Biology, 4-Raja S.C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Malini Sen
- Cancer Biology and Inflammatory Disorder Division, CSIR-Indian institute of Chemical Biology, 4-Raja S.C. Mullick Road, Jadavpur, Kolkata 700032, India
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160
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Filadi R, Greotti E, Turacchio G, Luini A, Pozzan T, Pizzo P. Presenilin 2 Modulates Endoplasmic Reticulum-Mitochondria Coupling by Tuning the Antagonistic Effect of Mitofusin 2. Cell Rep 2016; 15:2226-2238. [PMID: 27239030 DOI: 10.1016/j.celrep.2016.05.013] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 03/23/2016] [Accepted: 04/28/2016] [Indexed: 01/31/2023] Open
Abstract
Communication between organelles plays key roles in cell biology. In particular, physical and functional coupling of the endoplasmic reticulum (ER) and mitochondria is crucial for regulation of various physiological and pathophysiological processes. Here, we demonstrate that Presenilin 2 (PS2), mutations in which underlie familial Alzheimer's disease (FAD), promotes ER-mitochondria coupling only in the presence of mitofusin 2 (Mfn2). PS2 is not necessary for the antagonistic effect of Mfn2 on organelle coupling, although its abundance can tune it. The two proteins physically interact, whereas their homologues Mfn1 and PS1 are dispensable for this interplay. Moreover, PS2 mutants associated with FAD are more effective than the wild-type form in modulating ER-mitochondria tethering because their binding to Mfn2 in mitochondria-associated membranes is favored. We propose a revised model for ER-mitochondria interaction to account for these findings and discuss possible implications for FAD pathogenesis.
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Affiliation(s)
- Riccardo Filadi
- Department of Biomedical Sciences, University of Padua, via U. Bassi 58/B, Padua 35131, Italy
| | - Elisa Greotti
- Department of Biomedical Sciences, University of Padua, via U. Bassi 58/B, Padua 35131, Italy; Department of Biomedical Sciences, Institute of Neuroscience, Italian National Research Council (CNR), via U. Bassi 58/B, Padua 35131, Italy
| | - Gabriele Turacchio
- Department of Biomedical Sciences, Institute of Protein Biochemistry, Italian National Research Council (CNR), via P. Castellino 111, Naples 80131, Italy
| | - Alberto Luini
- Department of Biomedical Sciences, Institute of Protein Biochemistry, Italian National Research Council (CNR), via P. Castellino 111, Naples 80131, Italy
| | - Tullio Pozzan
- Department of Biomedical Sciences, University of Padua, via U. Bassi 58/B, Padua 35131, Italy; Venetian Institute of Molecular Medicine, via Orus 2, Padua 35131, Italy; Department of Biomedical Sciences, Institute of Neuroscience, Italian National Research Council (CNR), via U. Bassi 58/B, Padua 35131, Italy
| | - Paola Pizzo
- Department of Biomedical Sciences, University of Padua, via U. Bassi 58/B, Padua 35131, Italy.
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161
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Leal NS, Schreiner B, Pinho CM, Filadi R, Wiehager B, Karlström H, Pizzo P, Ankarcrona M. Mitofusin-2 knockdown increases ER-mitochondria contact and decreases amyloid β-peptide production. J Cell Mol Med 2016; 20:1686-95. [PMID: 27203684 PMCID: PMC4988279 DOI: 10.1111/jcmm.12863] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 03/04/2016] [Indexed: 12/28/2022] Open
Abstract
Mitochondria are physically and biochemically in contact with other organelles including the endoplasmic reticulum (ER). Such contacts are formed between mitochondria‐associated ER membranes (MAM), specialized subregions of ER, and the outer mitochondrial membrane (OMM). We have previously shown increased expression of MAM‐associated proteins and enhanced ER to mitochondria Ca2+ transfer from ER to mitochondria in Alzheimer's disease (AD) and amyloid β‐peptide (Aβ)‐related neuronal models. Here, we report that siRNA knockdown of mitofusin‐2 (Mfn2), a protein that is involved in the tethering of ER and mitochondria, leads to increased contact between the two organelles. Cells depleted in Mfn2 showed increased Ca2+ transfer from ER to mitchondria and longer stretches of ER forming contacts with OMM. Interestingly, increased contact resulted in decreased concentrations of intra‐ and extracellular Aβ40 and Aβ42. Analysis of γ‐secretase protein expression, maturation and activity revealed that the low Aβ concentrations were a result of impaired γ‐secretase complex function. Amyloid‐β precursor protein (APP), β‐site APP‐cleaving enzyme 1 and neprilysin expression as well as neprilysin activity were not affected by Mfn2 siRNA treatment. In summary, our data shows that modulation of ER–mitochondria contact affects γ‐secretase activity and Aβ generation. Increased ER–mitochondria contact results in lower γ‐secretase activity suggesting a new mechanism by which Aβ generation can be controlled.
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Affiliation(s)
- Nuno Santos Leal
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Bernadette Schreiner
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Catarina Moreira Pinho
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Riccardo Filadi
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Birgitta Wiehager
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Helena Karlström
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
| | - Paola Pizzo
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Maria Ankarcrona
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
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162
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Gautier CA, Erpapazoglou Z, Mouton-Liger F, Muriel MP, Cormier F, Bigou S, Duffaure S, Girard M, Foret B, Iannielli A, Broccoli V, Dalle C, Bohl D, Michel PP, Corvol JC, Brice A, Corti O. The endoplasmic reticulum-mitochondria interface is perturbed in PARK2 knockout mice and patients with PARK2 mutations. Hum Mol Genet 2016; 25:2972-2984. [PMID: 27206984 DOI: 10.1093/hmg/ddw148] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 05/10/2016] [Accepted: 05/10/2016] [Indexed: 12/13/2022] Open
Abstract
Mutations in PARK2, encoding the E3 ubiquitin protein ligase Parkin, are a common cause of autosomal recessive Parkinson's disease (PD). Loss of PARK2 function compromises mitochondrial quality by affecting mitochondrial biogenesis, bioenergetics, dynamics, transport and turnover. We investigated the impact of PARK2 dysfunction on the endoplasmic reticulum (ER)-mitochondria interface, which mediates calcium (Ca2+) exchange between the two compartments and is essential for Parkin-dependent mitophagy. Confocal and electron microscopy analyses showed the ER and mitochondria to be in closer proximity in primary fibroblasts from PARK2 knockout (KO) mice and PD patients with PARK2 mutations than in controls. Ca2+ flux to the cytosol was also modified, due to enhanced ER-to-mitochondria Ca2+ transfers, a change that was also observed in neurons derived from induced pluripotent stem cells of a patient with PARK2 mutations. Subcellular fractionation showed the abundance of the Parkin substrate mitofusin 2 (Mfn2), which is known to modulate the ER-mitochondria interface, to be specifically higher in the mitochondrion-associated ER membrane compartment in PARK2 KO tissue. Mfn2 downregulation or the exogenous expression of normal Parkin restored cytosolic Ca2+ transients in fibroblasts from patients with PARK2 mutations. In contrast, a catalytically inactive PD-related Parkin variant had no effect. Overall, our data suggest that Parkin is directly involved in regulating ER-mitochondria contacts and provide new insight into the role of the loss of Parkin function in PD development.
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Affiliation(s)
- Clément A Gautier
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Inserm, U1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, CNRS, UMR 7225, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Zoi Erpapazoglou
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Inserm, U1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, CNRS, UMR 7225, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - François Mouton-Liger
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Inserm, U1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, CNRS, UMR 7225, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Marie Paule Muriel
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Inserm, U1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, CNRS, UMR 7225, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Florence Cormier
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Inserm, U1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, CNRS, UMR 7225, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
- National Research Council (CNR), Institute of Neuroscience, Milan, Italy
| | - Stéphanie Bigou
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Inserm, U1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, CNRS, UMR 7225, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Sophie Duffaure
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Inserm, U1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, CNRS, UMR 7225, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Mathilde Girard
- CECS, I-Stem, AFM, Institute of Stem Cell Therapy and Exploration of Monogenic Diseases, 91030 Evry cedex, France
| | - Benjamin Foret
- CECS, I-Stem, AFM, Institute of Stem Cell Therapy and Exploration of Monogenic Diseases, 91030 Evry cedex, France
| | - Angelo Iannielli
- National Research Council (CNR), Institute of Neuroscience, Milan, Italy
- Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Vania Broccoli
- National Research Council (CNR), Institute of Neuroscience, Milan, Italy
- Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Carine Dalle
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Inserm, U1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, CNRS, UMR 7225, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Delphine Bohl
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Inserm, U1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, CNRS, UMR 7225, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Patrick P Michel
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Inserm, U1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, CNRS, UMR 7225, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Jean-Christophe Corvol
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Inserm, U1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, CNRS, UMR 7225, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
- Assistance-publique Hôpitaux de Paris, Inserm, CIC-1422, Department of Neurology, Hôpital Pitié-Salpêtrière, F-75013 Paris, France
| | - Alexis Brice
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Inserm, U1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, CNRS, UMR 7225, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
| | - Olga Corti
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Inserm, U1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, CNRS, UMR 7225, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013 Paris, France
- Bases moléculaires, physiopathologie et traitement des maladies neurodégénératives, Institut du Cerveau et de la Moelle épinière, ICM, F-75013 Paris, France
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163
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There's Something Wrong with my MAM; the ER-Mitochondria Axis and Neurodegenerative Diseases. Trends Neurosci 2016; 39:146-157. [PMID: 26899735 PMCID: PMC4780428 DOI: 10.1016/j.tins.2016.01.008] [Citation(s) in RCA: 329] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 01/19/2016] [Accepted: 01/21/2016] [Indexed: 12/18/2022]
Abstract
Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis with associated frontotemporal dementia (ALS/FTD) are major neurodegenerative diseases for which there are no cures. All are characterised by damage to several seemingly disparate cellular processes. The broad nature of this damage makes understanding pathogenic mechanisms and devising new treatments difficult. Can the different damaged functions be linked together in a common disease pathway and which damaged function should be targeted for therapy? Many functions damaged in neurodegenerative diseases are regulated by communications that mitochondria make with a specialised region of the endoplasmic reticulum (ER; mitochondria-associated ER membranes or 'MAM'). Moreover, several recent studies have shown that disturbances to ER-mitochondria contacts occur in neurodegenerative diseases. Here, we review these findings.
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164
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Qi H, Shuai J. Alzheimer's disease via enhanced calcium signaling caused by the decrease of endoplasmic reticulum-mitochondrial distance. Med Hypotheses 2016; 89:28-31. [PMID: 26968904 DOI: 10.1016/j.mehy.2016.01.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 01/30/2016] [Indexed: 10/22/2022]
Abstract
It has long been recognized that Ca(2+) dysregulation is relevant to the initiation of Alzheimer's disease (AD), and most recent works have suggested that increased cross-talk between endoplasmic reticulum (ER) and mitochondria plays an important role in the pathogenesis of the disease. However, the detailed mechanism involved has not been fully elucidated. Owing to its importance in the regulation of Ca(2+) signaling, ER-mitochondrial distance in the neurons is tightly controlled in the physiological conditions. When the distance is decreased, Ca(2+) overload occurs both in the cytosol and mitochondria. The cytosolic Ca(2+) overload can (1) hyperactivate Ca(2+)-dependent enzymes, which in turn regulate activities of pro-apoptotic BCL-2 family proteins, causing mitochondrial outer membrane permeabilization and thereby resulting in the release of cytochrome c to activate caspase-3; (2) indirectly activate caspase-3 through the activation of caspase-12; and (3) promote the production and aggregation of β-amyloid. The three pathways eventually trigger neuronal apoptotic cell death. The mitochondrial Ca(2+) overload can lead to increased generation of reactive oxygen species, inducing the opening of the mitochondrial permeability transition pore and ultimately causing neuronal apoptotic and necrotic cell death. The resultant death of neurons which are responsible for memory and cognition would contribute to the pathogenesis of AD. Therefore, we propose that the reduction in the distance between ER and mitochondria may be implicated in AD pathology by enhanced Ca(2+) signaling, which provides a more complete picture of the Ca(2+) hypothesis of AD.
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Affiliation(s)
- Hong Qi
- Complex Systems Research Center, Shanxi University, Taiyuan 030006, PR China.
| | - Jianwei Shuai
- Department of Physics, Xiamen University, Xiamen 361005, PR China; State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, Xiamen University, Xiamen 361005, PR China.
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165
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Milisav I, Šuput D, Ribarič S. Unfolded Protein Response and Macroautophagy in Alzheimer's, Parkinson's and Prion Diseases. Molecules 2015; 20:22718-56. [PMID: 26694349 PMCID: PMC6332363 DOI: 10.3390/molecules201219865] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 11/30/2015] [Accepted: 12/09/2015] [Indexed: 12/13/2022] Open
Abstract
Proteostasis are integrated biological pathways within cells that control synthesis, folding, trafficking and degradation of proteins. The absence of cell division makes brain proteostasis susceptible to age-related changes and neurodegeneration. Two key processes involved in sustaining normal brain proteostasis are the unfolded protein response and autophagy. Alzheimer’s disease (AD), Parkinson’s disease (PD) and prion diseases (PrDs) have different clinical manifestations of neurodegeneration, however, all share an accumulation of misfolded pathological proteins associated with perturbations in unfolded protein response and macroautophagy. While both the unfolded protein response and macroautophagy play an important role in the prevention and attenuation of AD and PD progression, only macroautophagy seems to play an important role in the development of PrDs. Macroautophagy and unfolded protein response can be modulated by pharmacological interventions. However, further research is necessary to better understand the regulatory pathways of both processes in health and neurodegeneration to be able to develop new therapeutic interventions.
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Affiliation(s)
- Irina Milisav
- Institute of Pathophysiology, Faculty of Medicine, Zaloška 4, Ljubljana SI-1000, Slovenia.
- Faculty of Health Sciences, Zdravstvena pot 5, SI-1000 Ljubljana, Slovenija.
| | - Dušan Šuput
- Institute of Pathophysiology, Faculty of Medicine, Zaloška 4, Ljubljana SI-1000, Slovenia.
| | - Samo Ribarič
- Institute of Pathophysiology, Faculty of Medicine, Zaloška 4, Ljubljana SI-1000, Slovenia.
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166
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A γ-Secretase Independent Role for Presenilin in Calcium Homeostasis Impacts Mitochondrial Function and Morphology in Caenorhabditis elegans. Genetics 2015; 201:1453-66. [PMID: 26500256 DOI: 10.1534/genetics.115.182808] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Accepted: 10/19/2015] [Indexed: 12/21/2022] Open
Abstract
Mutations in the presenilin (PSEN) encoding genes (PSEN1 and PSEN2) occur in most early onset familial Alzheimer's Disease. Despite the identification of the involvement of PSEN in Alzheimer's Disease (AD) ∼20 years ago, the underlying role of PSEN in AD is not fully understood. To gain insight into the biological function of PSEN, we investigated the role of the PSEN homolog SEL-12 in Caenorhabditis elegans. Using genetic, cell biological, and pharmacological approaches, we demonstrate that mutations in sel-12 result in defects in calcium homeostasis, leading to mitochondrial dysfunction. Moreover, consistent with mammalian PSEN, we provide evidence that SEL-12 has a critical role in mediating endoplasmic reticulum (ER) calcium release. Furthermore, we found that in SEL-12-deficient animals, calcium transfer from the ER to the mitochondria leads to fragmentation of the mitochondria and mitochondrial dysfunction. Additionally, we show that the impact that SEL-12 has on mitochondrial function is independent of its role in Notch signaling, γ-secretase proteolytic activity, and amyloid plaques. Our results reveal a critical role for PSEN in mediating mitochondrial function by regulating calcium transfer from the ER to the mitochondria.
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167
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Duggan SP, McCarthy JV. Beyond γ-secretase activity: The multifunctional nature of presenilins in cell signalling pathways. Cell Signal 2015; 28:1-11. [PMID: 26498858 DOI: 10.1016/j.cellsig.2015.10.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 10/19/2015] [Indexed: 01/24/2023]
Abstract
The presenilins are the catalytic subunit of the membrane-embedded tetrameric γ-secretase protease complexes. More that 90 transmembrane proteins have been reported to be γ-secretase substrates, including the widely studied amyloid precursor protein (APP) and the Notch receptor, which are precursors for the generation of amyloid-β peptides and biologically active APP intracellular domain (AICD) and Notch intracellular domain (NICD). The diversity of γ-secretase substrates highlights the importance of presenilin-dependent γ-secretase protease activities as a regulatory mechanism in a range of biological systems. However, there is also a growing body of evidence that supports the existence of γ-secretase-independent functions for the presenilins in the regulation and progression of an array of cell signalling pathways. In this review, we will present an overview of current literature that proposes evolutionarily conserved presenilin functions outside of the γ-secretase complex, with a focus on the suggested role of the presenilins in the regulation of Wnt/β-catenin signalling, protein trafficking and degradation, calcium homeostasis and apoptosis.
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Affiliation(s)
- Stephen P Duggan
- Signal Transduction Laboratory, School of Biochemistry & Cell Biology, ABCRF, Western Gateway Building, University College Cork, Cork, Ireland
| | - Justin V McCarthy
- Signal Transduction Laboratory, School of Biochemistry & Cell Biology, ABCRF, Western Gateway Building, University College Cork, Cork, Ireland.
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168
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Lim Y, Cho IT, Schoel LJ, Cho G, Golden JA. Hereditary spastic paraplegia-linked REEP1 modulates endoplasmic reticulum/mitochondria contacts. Ann Neurol 2015. [PMID: 26201691 DOI: 10.1002/ana.24488] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Mutations in receptor expression enhancing protein 1 (REEP1) are associated with hereditary spastic paraplegias (HSPs). Although axonal degeneration is thought to be a predominant feature in HSP, the role of REEP1 mutations in degeneration is largely unknown. Previous studies have implicated a role for REEP1 in the endoplasmic reticulum (ER), whereas others localized REEP1 with mitochondria. We sought to resolve the cellular localization of REEP1 and further elucidate the pathobiology underlying REEP1 mutations in patients. METHODS A combination of cellular imaging and biochemical approaches was used to refine the cellular localization of REEP1. Next, Reep1 mutations associated with HSP were functionally tested in neuritic growth and degeneration assays using mouse cortical culture. Finally, a novel assay was developed and used with wild-type and mutant Reep1s to measure the interactions between the ER and mitochondria. RESULTS We found that REEP1 is present at the ER-mitochondria interface, and it contains subdomains for mitochondrial as well as ER localization. Knockdown of Reep1 and expression of pathological Reep1 mutations resulted in neuritic growth defects and degeneration. Finally, using our novel split-RLuc8 assay, we show that REEP1 facilitates ER-mitochondria interactions, a function diminished by disease-associated mutations. INTERPRETATION Our data potentially reconcile the current conflicting reports regarding REEP1 being either an ER or a mitochondrial protein. Furthermore, our results connect, for the first time, the disrupted ER-mitochondria interactions to a failure in maintaining health of long axons in HSPs. Finally, the split-RLuc8 assay offers a new tool to identify potential drugs for multiple neurodegenerative diseases with ER-mitochondria interaction defects.
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Affiliation(s)
- Youngshin Lim
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Il-Taeg Cho
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Leah J Schoel
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Ginam Cho
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Jeffrey A Golden
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
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169
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Abeti R, Abramov AY. Mitochondrial Ca2+ in neurodegenerative disorders. Pharmacol Res 2015; 99:377-81. [DOI: 10.1016/j.phrs.2015.05.007] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 05/11/2015] [Accepted: 05/15/2015] [Indexed: 01/08/2023]
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170
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Marini ES, Giampietri C, Petrungaro S, Conti S, Filippini A, Scorrano L, Ziparo E. The endogenous caspase-8 inhibitor c-FLIPL regulates ER morphology and crosstalk with mitochondria. Cell Death Differ 2015; 22:1131-43. [PMID: 25501600 PMCID: PMC4572861 DOI: 10.1038/cdd.2014.197] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 09/11/2014] [Accepted: 10/27/2014] [Indexed: 12/11/2022] Open
Abstract
Components of the death receptor-mediated pathways like caspase-8 have been identified in complexes at intracellular membranes to spatially restrict the processing of local targets. In this study, we report that the long isoform of the cellular FLICE-inhibitory protein (c-FLIP(L)), a well-known inhibitor of the extrinsic cell death initiator caspase-8, localizes at the endoplasmic reticulum (ER) and mitochondria-associated membranes (MAMs). ER morphology was disrupted and ER Ca(2+)-release as well as ER-mitochondria tethering was decreased in c-FLIP(-/-) mouse embryonic fibroblasts (MEFs). Mechanistically, c-FLIP ablation resulted in enhanced basal caspase-8 activation and in caspase-mediated processing of the ER-shaping protein reticulon-4 (RTN4) that was corrected by re-introduction of c-FLIP(L) and caspase inhibition, resulting in the recovery of a normal ER morphology and ER-mitochondria juxtaposition. Thus, the caspase-8 inhibitor c-FLIP(L) emerges as a component of the MAMs signaling platforms, where caspases appear to regulate ER morphology and ER-mitochondria crosstalk by impinging on ER-shaping proteins like the RTN4.
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Affiliation(s)
- E S Marini
- Istituto Pasteur-Fondazione Cenci Bolognetti, DAHFMO – Section of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - C Giampietri
- Istituto Pasteur-Fondazione Cenci Bolognetti, DAHFMO – Section of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - S Petrungaro
- Istituto Pasteur-Fondazione Cenci Bolognetti, DAHFMO – Section of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - S Conti
- Istituto Pasteur-Fondazione Cenci Bolognetti, DAHFMO – Section of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - A Filippini
- Istituto Pasteur-Fondazione Cenci Bolognetti, DAHFMO – Section of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy
| | - L Scorrano
- Department of Biology, University of Padua, Padua, Italy
- Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine, Padua, Italy
| | - E Ziparo
- Istituto Pasteur-Fondazione Cenci Bolognetti, DAHFMO – Section of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy
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171
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Liang J, Kulasiri D, Samarasinghe S. Ca2+ dysregulation in the endoplasmic reticulum related to Alzheimer's disease: A review on experimental progress and computational modeling. Biosystems 2015; 134:1-15. [PMID: 25998697 DOI: 10.1016/j.biosystems.2015.05.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 05/12/2015] [Accepted: 05/12/2015] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) is a devastating, incurable neurodegenerative disease affecting millions of people worldwide. Dysregulation of intracellular Ca(2+) signaling has been observed as an early event prior to the presence of clinical symptoms of AD and is believed to be a crucial factor contributing to its pathogenesis. The progressive and sustaining increase in the resting level of cytosolic Ca(2+) will affect downstream activities and neural functions. This review focuses on the issues relating to the increasing Ca(2+) release from the endoplasmic reticulum (ER) observed in AD neurons. Numerous research papers have suggested that the dysregulation of ER Ca(2+) homeostasis is associated with mutations in the presenilin genes and amyloid-β oligomers. These disturbances could happen at many different points in the signaling process, directly affecting ER Ca(2+) channels or interfering with related pathways, which makes it harder to reveal the underlying mechanisms. This review paper also shows that computational modeling is a powerful tool in Ca(2+) signaling studies and discusses the progress in modeling related to Ca(2+) dysregulation in AD research.
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Affiliation(s)
- Jingyi Liang
- Centre for Advanced Computational Solutions (C-fACS), Lincoln University, Christchurch, New Zealand; Department of Molecular Biosciences, Lincoln University, Christchurch, New Zealand
| | - Don Kulasiri
- Centre for Advanced Computational Solutions (C-fACS), Lincoln University, Christchurch, New Zealand; Department of Molecular Biosciences, Lincoln University, Christchurch, New Zealand.
| | - Sandhya Samarasinghe
- Centre for Advanced Computational Solutions (C-fACS), Lincoln University, Christchurch, New Zealand; Department of Informatics and Enabling Technologies, Lincoln University, Christchurch, New Zealand
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172
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Guardia-Laguarta C, Area-Gomez E, Schon EA, Przedborski S. A new role for α-synuclein in Parkinson's disease: Alteration of ER-mitochondrial communication. Mov Disord 2015; 30:1026-33. [DOI: 10.1002/mds.26239] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 03/10/2015] [Accepted: 03/19/2015] [Indexed: 12/28/2022] Open
Affiliation(s)
| | - Estela Area-Gomez
- Department of Neurology; Columbia University Medical Center; New York NY USA
| | - Eric A. Schon
- Department of Neurology; Columbia University Medical Center; New York NY USA
- Department of Genetics and Development; Columbia University Medical Center; New York NY USA
| | - Serge Przedborski
- Department of Pathology and Cell Biology; Columbia University Medical Center; New York NY USA
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173
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Mitofusin 2 ablation increases endoplasmic reticulum-mitochondria coupling. Proc Natl Acad Sci U S A 2015; 112:E2174-81. [PMID: 25870285 DOI: 10.1073/pnas.1504880112] [Citation(s) in RCA: 416] [Impact Index Per Article: 46.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The organization and mutual interactions between endoplasmic reticulum (ER) and mitochondria modulate key aspects of cell pathophysiology. Several proteins have been suggested to be involved in keeping ER and mitochondria at a correct distance. Among them, in mammalian cells, mitofusin 2 (Mfn2), located on both the outer mitochondrial membrane and the ER surface, has been proposed to be a physical tether between the two organelles, forming homotypic interactions and heterocomplexes with its homolog Mfn1. Recently, this widely accepted model has been challenged using quantitative EM analysis. Using a multiplicity of morphological, biochemical, functional, and genetic approaches, we demonstrate that Mfn2 ablation increases the structural and functional ER-mitochondria coupling. In particular, we show that in different cell types Mfn2 ablation or silencing increases the close contacts between the two organelles and strengthens the efficacy of inositol trisphosphate (IP3)-induced Ca(2+) transfer from the ER to mitochondria, sensitizing cells to a mitochondrial Ca(2+) overload-dependent death. We also show that the previously reported discrepancy between electron and fluorescence microscopy data on ER-mitochondria proximity in Mfn2-ablated cells is only apparent. By using a different type of morphological analysis of fluorescent images that takes into account (and corrects for) the gross modifications in mitochondrial shape resulting from Mfn2 ablation, we demonstrate that an increased proximity between the organelles is also observed by confocal microscopy when Mfn2 levels are reduced. Based on these results, we propose a new model for ER-mitochondria juxtaposition in which Mfn2 works as a tethering antagonist preventing an excessive, potentially toxic, proximity between the two organelles.
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174
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Arasaki K, Shimizu H, Mogari H, Nishida N, Hirota N, Furuno A, Kudo Y, Baba M, Baba N, Cheng J, Fujimoto T, Ishihara N, Ortiz-Sandoval C, Barlow LD, Raturi A, Dohmae N, Wakana Y, Inoue H, Tani K, Dacks JB, Simmen T, Tagaya M. A role for the ancient SNARE syntaxin 17 in regulating mitochondrial division. Dev Cell 2015; 32:304-17. [PMID: 25619926 DOI: 10.1016/j.devcel.2014.12.011] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 10/22/2014] [Accepted: 12/12/2014] [Indexed: 12/11/2022]
Abstract
Recent evidence suggests that endoplasmic reticulum (ER) tubules mark the sites where the GTPase Drp1 promotes mitochondrial fission via a largely unknown mechanism. Here, we show that the SNARE protein syntaxin 17 (Syn17) is present on raft-like structures of ER-mitochondria contact sites and promotes mitochondrial fission by determining Drp1 localization and activity. The hairpin-like C-terminal hydrophobic domain, including Lys-254, but not the SNARE domain, is important for this regulation. Syn17 also regulates ER Ca(2+) homeostasis and interferes with Rab32-mediated regulation of mitochondrial dynamics. Starvation disrupts the Syn17-Drp1 interaction, thus favoring mitochondrial elongation during autophagy. Because we also demonstrate that Syn17 is an ancient SNARE, our findings suggest that Syn17 is one of the original key regulators for ER-mitochondria contact sites present in the last eukaryotic common ancestor. As such, Syn17 acts as a switch that responds to nutrient conditions and integrates functions for the ER and autophagosomes with mitochondrial dynamics.
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Affiliation(s)
- Kohei Arasaki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Hiroaki Shimizu
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Hirofumi Mogari
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Naoki Nishida
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Naohiko Hirota
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Akiko Furuno
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Yoshihisa Kudo
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Misuzu Baba
- Research Institute for Science and Technology, Kogakuin University, Hachioji, Tokyo 192-0015, Japan; Informatics Program, Graduate School of Engineering, Kogakuin University, Hachioji, Tokyo 192-0015, Japan
| | - Norio Baba
- Informatics Program, Graduate School of Engineering, Kogakuin University, Hachioji, Tokyo 192-0015, Japan
| | - Jinglei Cheng
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Toyoshi Fujimoto
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Naotada Ishihara
- Department of Protein Biochemistry, Institute of Life Science, Kurume University, Kurume, Fukuoka 839-0864, Japan
| | | | - Lael D Barlow
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Arun Raturi
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Naoshi Dohmae
- Biomolecular Characterization Team, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yuichi Wakana
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Hiroki Inoue
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Katsuko Tani
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Joel B Dacks
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Thomas Simmen
- Department of Cell Biology, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Mitsuo Tagaya
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
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175
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Identification of tetrahydrocarbazoles as novel multifactorial drug candidates for treatment of Alzheimer's disease. Transl Psychiatry 2014; 4:e489. [PMID: 25514752 PMCID: PMC4270312 DOI: 10.1038/tp.2014.132] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 10/12/2014] [Accepted: 11/17/2014] [Indexed: 01/08/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative brain disorder and the most frequent cause of dementia. To date, there are only a few approved drugs for AD, which show little or no effect on disease progression. Impaired intracellular calcium homeostasis is believed to occur early in the cascade of events leading to AD. Here, we examined the possibility of normalizing the disrupted calcium homeostasis in the endoplasmic reticulum (ER) store as an innovative approach for AD drug discovery. High-throughput screening of a small-molecule compound library led to the identification of tetrahydrocarbazoles, a novel multifactorial class of compounds that can normalize the impaired ER calcium homeostasis. We found that the tetrahydrocarbazole lead structure, first, dampens the enhanced calcium release from ER in HEK293 cells expressing familial Alzheimer's disease (FAD)-linked presenilin 1 mutations. Second, the lead structure also improves mitochondrial function, measured by increased mitochondrial membrane potential. Third, the same lead structure also attenuates the production of amyloid-beta (Aβ) peptides by decreasing the cleavage of amyloid precursor protein (APP) by β-secretase, without notably affecting α- and γ-secretase cleavage activities. Considering the beneficial effects of tetrahydrocarbazoles addressing three key pathological aspects of AD, these compounds hold promise for the development of potentially effective AD drug candidates.
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176
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Huang HC, Tang D, Lu SY, Jiang ZF. Endoplasmic reticulum stress as a novel neuronal mediator in Alzheimer's disease. Neurol Res 2014; 37:366-74. [PMID: 25310352 DOI: 10.1179/1743132814y.0000000448] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Alzheimer's disease (AD) is one of the most common types of progressive dementias. The typical neuropathological changes in AD include extracellular senile plaques, intracellular neurofibrillary tangles, and loss of neurons. The pathogenetic mechanism of this disease is not comprehensively understood yet. Recently, endoplasmic reticulum stress (ER stress) has been considered as a potential event involved in AD development. Some AD-related factors, such as misfolded protein and Ca(2+) depletion, could disrupt the homeostasis of ER lumen. In AD, the aggregated amyloid-beta peptide (Abeta) could induce ER stress in an assembly dependent way. The presenilin has been identified as a Ca(2+) channel. Mutations of presenilin could change the balance of Ca(2+) in ER lumen and thus disrupts the ER homeostasis. Furthermore, the ER stress could lead to cellular disorders like inflammation. Through activating the expression of inflammatory factors, ER stress triggers inflammatory response in AD pathology. Herein, we reviewed the recent progress of ER stress-induced unfolded protein response (UPR) and the roles of ER stress in AD pathological process.
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177
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Tubbs E, Theurey P, Vial G, Bendridi N, Bravard A, Chauvin MA, Ji-Cao J, Zoulim F, Bartosch B, Ovize M, Vidal H, Rieusset J. Mitochondria-associated endoplasmic reticulum membrane (MAM) integrity is required for insulin signaling and is implicated in hepatic insulin resistance. Diabetes 2014; 63:3279-94. [PMID: 24947355 DOI: 10.2337/db13-1751] [Citation(s) in RCA: 301] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Mitochondria-associated endoplasmic reticulum (ER) membranes (MAMs) are functional domains between both organelles involved in Ca(2+) exchange, through the voltage-dependent anion channel (VDAC)-1/glucose-regulated protein 75 (Grp75)/inositol 1,4,5-triphosphate receptor (IP3R)-1 complex, and regulating energy metabolism. Whereas mitochondrial dysfunction, ER stress, and altered Ca(2+) homeostasis are associated with altered insulin signaling, the implication of MAM dysfunctions in insulin resistance is unknown. Here we validated an approach based on in situ proximity ligation assay to detect and quantify VDAC1/IP3R1 and Grp75/IP3R1 interactions at the MAM interface. We demonstrated that MAM integrity is required for insulin signaling and that induction of MAM prevented palmitate-induced alterations of insulin signaling in HuH7 cells. Disruption of MAM integrity by genetic or pharmacological inhibition of the mitochondrial MAM protein, cyclophilin D (CypD), altered insulin signaling in mouse and human primary hepatocytes and treatment of CypD knockout mice with metformin improved both insulin sensitivity and MAM integrity. Furthermore, ER-mitochondria interactions are altered in liver of both ob/ob and diet-induced insulin-resistant mice and improved by rosiglitazone treatment in the latter. Finally, increasing organelle contacts by overexpressing CypD enhanced insulin action in primary hepatocytes of diabetic mice. Collectively, our data reveal a new role of MAM integrity in hepatic insulin action and resistance, providing a novel target for the modulation of insulin action.
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Affiliation(s)
- Emily Tubbs
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1235, INSA of Lyon, Rockefeller and Charles Merieux Lyon-Sud Medical Universities, Lyon, France
| | - Pierre Theurey
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1235, INSA of Lyon, Rockefeller and Charles Merieux Lyon-Sud Medical Universities, Lyon, France
| | - Guillaume Vial
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1235, INSA of Lyon, Rockefeller and Charles Merieux Lyon-Sud Medical Universities, Lyon, France
| | - Nadia Bendridi
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1235, INSA of Lyon, Rockefeller and Charles Merieux Lyon-Sud Medical Universities, Lyon, France
| | - Amélie Bravard
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1235, INSA of Lyon, Rockefeller and Charles Merieux Lyon-Sud Medical Universities, Lyon, France
| | - Marie-Agnès Chauvin
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1235, INSA of Lyon, Rockefeller and Charles Merieux Lyon-Sud Medical Universities, Lyon, France
| | - Jingwei Ji-Cao
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1235, INSA of Lyon, Rockefeller and Charles Merieux Lyon-Sud Medical Universities, Lyon, France
| | - Fabien Zoulim
- INSERM UMR-1052, Cancer Research Center of Lyon, Lyon 1 University, Hospices Civils de Lyon, Lyon, France
| | - Birke Bartosch
- INSERM UMR-1052, Cancer Research Center of Lyon, Lyon 1 University, Hospices Civils de Lyon, Lyon, France
| | - Michel Ovize
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1235, INSA of Lyon, Rockefeller and Charles Merieux Lyon-Sud Medical Universities, Lyon, France Hospices Civils de Lyon, Louis Pradel Hospital, Cardiovascular Functional Explorations Service and CIC of Lyon, Lyon, France
| | - Hubert Vidal
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1235, INSA of Lyon, Rockefeller and Charles Merieux Lyon-Sud Medical Universities, Lyon, France Hospices Civils de Lyon, Lyon-Sud Hospital, Endocrinology, Diabetology, and Nutrition Service, Pierre-Bénite, France
| | - Jennifer Rieusset
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1235, INSA of Lyon, Rockefeller and Charles Merieux Lyon-Sud Medical Universities, Lyon, France Hospices Civils de Lyon, Lyon-Sud Hospital, Endocrinology, Diabetology, and Nutrition Service, Pierre-Bénite, France
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178
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Rainbolt TK, Saunders JM, Wiseman RL. Stress-responsive regulation of mitochondria through the ER unfolded protein response. Trends Endocrinol Metab 2014; 25:528-37. [PMID: 25048297 DOI: 10.1016/j.tem.2014.06.007] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/18/2014] [Accepted: 06/19/2014] [Indexed: 12/31/2022]
Abstract
The endoplasmic reticulum (ER) and mitochondria form physical interactions involved in the regulation of biologic functions including mitochondrial bioenergetics and apoptotic signaling. To coordinate these functions during stress, cells must coregulate ER and mitochondria through stress-responsive signaling pathways such as the ER unfolded protein response (UPR). Although the UPR is traditionally viewed as a signaling pathway responsible for regulating ER proteostasis, it is becoming increasingly clear that the protein kinase RNA (PKR)-like endoplasmic reticulum kinase (PERK) signaling pathway within the UPR can also regulate mitochondria proteostasis and function in response to pathologic insults that induce ER stress. Here, we discuss the contributions of PERK in coordinating ER-mitochondrial activities and describe the mechanisms by which PERK adapts mitochondrial proteostasis and function in response to ER stress.
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Affiliation(s)
- T Kelly Rainbolt
- Department of Molecular and Experimental Medicine, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jaclyn M Saunders
- Department of Molecular and Experimental Medicine, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - R Luke Wiseman
- Department of Molecular and Experimental Medicine, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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179
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Daidone V, Barbon G, Pontara E, Cattini GM, Gallinaro L, Zampese E, Pizzo P, Casonato A. Loss of cysteine 584 impairs the storage and release, but not the synthesis of von Willebrand factor. Thromb Haemost 2014; 112:1159-66. [PMID: 25230768 DOI: 10.1160/th14-04-0391] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 07/22/2014] [Indexed: 11/05/2022]
Abstract
Cysteines play a key part in von Willebrand factor (VWF) dimerisation and polymerisation, and their loss may severely affect VWF structure and function. We report on three patients with type 3 von Willebrand disease carrying the new c.1751G>T missense mutation that induces the substitution of cysteine 584 by phenylalanine (C584F), and the deletion of seven nucleotides in exon 7 (c.729_735del), producing a premature stop codon at position 454 (E244Lfs*211). VWF was almost undetectable in the patients' plasma and platelets, while a single, poorly represented, oligomer emerged on plasma VWF multimer analysis. No post-DDAVP increase in VWF and factor VIII was observed. Expressing human recombinant C584F-VWF in HEK293T cells showed that C584F-VWF was synthesised and multimerised but not secreted - apart from the first oligomer, which was slightly represented in the conditioned medium, with a pattern similar to the patients' plasma VWF. The in vitro expression of the E244Lfs*211-VWF revealed a defective synthesis of the mutated VWF, with a behavior typical of loss of function mutations. Cellular trafficking, investigated in HEK293 cells, indicated a normal C584F-VWF content in the endoplasmic reticulum and Golgi apparatus, confirming the synthesis and multimerisation of C584F-VWF. No pseudo-Weibel Palade bodies were demonstrable, however, suggesting that C584F mutation impairs the storage of C584F-VWF. These findings point to cysteine 584 having a role in the release of VWF and its targeting to pseudo-Weibel Palade bodies in vitro, as well as in its storage and release by endothelial cells in vivo.
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Affiliation(s)
| | | | | | | | | | | | | | - A Casonato
- A. Casonato, Via Ospedale Civile 105, 35128 Padova, Italy, Tel.: +39 049 821 7177, Fax: +39 049 657391, E-mail:
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180
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Abstract
SIGNIFICANCE Store-operated Ca2+ entry (SOCE) is a ubiquitous Ca2+ signaling mechanism triggered by Ca2+ depletion of the endoplasmic reticulum (ER) and by a variety of cellular stresses. Reactive oxygen species (ROS) are often concomitantly produced in response to these stresses, however, the relationship between redox signaling and SOCE is not completely understood. Various cardiovascular, neurological, and immune diseases are associated with alterations in both Ca2+ signaling and ROS production, and thus understanding this relationship has therapeutic implications. RECENT ADVANCES Several reactive cysteine modifications in stromal interaction molecule (STIM) and Orai proteins comprising the core SOCE machinery were recently shown to modulate SOCE in a redox-dependent manner. Moreover, STIM1 and Orai1 expression levels may reciprocally regulate and be affected by responses to oxidative stress. ER proteins involved in oxidative protein folding have gained increased recognition as important sources of ROS, and the recent discovery of their accumulation in contact sites between the ER and mitochondria provides a further link between ROS production and intracellular Ca2+ handling. CRITICAL ISSUES AND FUTURE DIRECTIONS Future research should aim to establish the complete set of SOCE controlling molecules, to determine their redox-sensitive residues, and to understand how intracellular Ca2+ stores dynamically respond to different types of stress. Mapping the precise nature and functional consequence of key redox-sensitive components of the pre- and post-translational control of SOCE machinery and of proteins regulating ER calcium content will be pivotal in advancing our understanding of the complex cross-talk between redox and Ca2+ signaling.
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Affiliation(s)
- Paula Nunes
- Department of Cell Physiology and Metabolism, University of Geneva , Geneva, Switzerland
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181
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Brini M, Calì T, Ottolini D, Carafoli E. Neuronal calcium signaling: function and dysfunction. Cell Mol Life Sci 2014; 71:2787-814. [PMID: 24442513 PMCID: PMC11113927 DOI: 10.1007/s00018-013-1550-7] [Citation(s) in RCA: 423] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 12/15/2013] [Accepted: 12/30/2013] [Indexed: 01/07/2023]
Abstract
Calcium (Ca(2+)) is an universal second messenger that regulates the most important activities of all eukaryotic cells. It is of critical importance to neurons as it participates in the transmission of the depolarizing signal and contributes to synaptic activity. Neurons have thus developed extensive and intricate Ca(2+) signaling pathways to couple the Ca(2+) signal to their biochemical machinery. Ca(2+) influx into neurons occurs through plasma membrane receptors and voltage-dependent ion channels. The release of Ca(2+) from the intracellular stores, such as the endoplasmic reticulum, by intracellular channels also contributes to the elevation of cytosolic Ca(2+). Inside the cell, Ca(2+) is controlled by the buffering action of cytosolic Ca(2+)-binding proteins and by its uptake and release by mitochondria. The uptake of Ca(2+) in the mitochondrial matrix stimulates the citric acid cycle, thus enhancing ATP production and the removal of Ca(2+) from the cytosol by the ATP-driven pumps in the endoplasmic reticulum and the plasma membrane. A Na(+)/Ca(2+) exchanger in the plasma membrane also participates in the control of neuronal Ca(2+). The impaired ability of neurons to maintain an adequate energy level may impact Ca(2+) signaling: this occurs during aging and in neurodegenerative disease processes. The focus of this review is on neuronal Ca(2+) signaling and its involvement in synaptic signaling processes, neuronal energy metabolism, and neurotransmission. The contribution of altered Ca(2+) signaling in the most important neurological disorders will then be considered.
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Affiliation(s)
- Marisa Brini
- Department of Biology, University of Padova, Via U.Bassi, 58/b, 35131 Padua, Italy
| | - Tito Calì
- Department of Biology, University of Padova, Via U.Bassi, 58/b, 35131 Padua, Italy
| | - Denis Ottolini
- Department of Biology, University of Padova, Via U.Bassi, 58/b, 35131 Padua, Italy
| | - Ernesto Carafoli
- Venetian Institute for Molecular Medicine (VIMM), Via G.Orus, 2, 35129 Padua, Italy
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182
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Stoica R, De Vos KJ, Paillusson S, Mueller S, Sancho RM, Lau KF, Vizcay-Barrena G, Lin WL, Xu YF, Lewis J, Dickson DW, Petrucelli L, Mitchell JC, Shaw CE, Miller CCJ. ER-mitochondria associations are regulated by the VAPB-PTPIP51 interaction and are disrupted by ALS/FTD-associated TDP-43. Nat Commun 2014; 5:3996. [PMID: 24893131 PMCID: PMC4046113 DOI: 10.1038/ncomms4996] [Citation(s) in RCA: 435] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 04/29/2014] [Indexed: 12/12/2022] Open
Abstract
Mitochondria and the endoplasmic reticulum (ER) form tight structural associations and these facilitate a number of cellular functions. However, the mechanisms by which regions of the ER become tethered to mitochondria are not properly known. Understanding these mechanisms is not just important for comprehending fundamental physiological processes but also for understanding pathogenic processes in some disease states. In particular, disruption to ER-mitochondria associations is linked to some neurodegenerative diseases. Here we show that the ER-resident protein VAPB interacts with the mitochondrial protein tyrosine phosphatase-interacting protein-51 (PTPIP51) to regulate ER-mitochondria associations. Moreover, we demonstrate that TDP-43, a protein pathologically linked to amyotrophic lateral sclerosis and fronto-temporal dementia perturbs ER-mitochondria interactions and that this is associated with disruption to the VAPB-PTPIP51 interaction and cellular Ca(2+) homeostasis. Finally, we show that overexpression of TDP-43 leads to activation of glycogen synthase kinase-3β (GSK-3β) and that GSK-3β regulates the VAPB-PTPIP51 interaction. Our results describe a new pathogenic mechanism for TDP-43.
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Affiliation(s)
- Radu Stoica
- Department of Neuroscience, Institute of Psychiatry, Kings
College London, London
SE5 8AF, UK
- Clinical Neurosciences, Institute of Psychiatry, Kings
College London, London
SE5 8AF, UK
- These authors contributed equally to this work
| | - Kurt J. De Vos
- Department of Neuroscience, Institute of Psychiatry, Kings
College London, London
SE5 8AF, UK
- Clinical Neurosciences, Institute of Psychiatry, Kings
College London, London
SE5 8AF, UK
- These authors contributed equally to this work
- Present address: Sheffield Institute for Translational Neuroscience, University of Sheffield, South Yorkshire S10 2HQ, UK
| | - Sébastien Paillusson
- Department of Neuroscience, Institute of Psychiatry, Kings
College London, London
SE5 8AF, UK
- Clinical Neurosciences, Institute of Psychiatry, Kings
College London, London
SE5 8AF, UK
| | - Sarah Mueller
- Department of Neuroscience, Institute of Psychiatry, Kings
College London, London
SE5 8AF, UK
- Clinical Neurosciences, Institute of Psychiatry, Kings
College London, London
SE5 8AF, UK
| | - Rosa M. Sancho
- Department of Neuroscience, Institute of Psychiatry, Kings
College London, London
SE5 8AF, UK
- Clinical Neurosciences, Institute of Psychiatry, Kings
College London, London
SE5 8AF, UK
- Present address: Alzheimer’s Research UK, Cambridge
CB21 6AD, UK
| | - Kwok-Fai Lau
- Department of Neuroscience, Institute of Psychiatry, Kings
College London, London
SE5 8AF, UK
- Present address: Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR
| | - Gema Vizcay-Barrena
- Centre for Ultrastructural Imaging, King’s
College London, London
SE5 8AF, UK
| | - Wen-Lang Lin
- Department of Neuroscience, Mayo Clinic,
Jacksonville, Florida
32224, USA
| | - Ya-Fei Xu
- Department of Neuroscience, Mayo Clinic,
Jacksonville, Florida
32224, USA
| | - Jada Lewis
- Department of Neuroscience, Mayo Clinic,
Jacksonville, Florida
32224, USA
| | - Dennis W. Dickson
- Department of Neuroscience, Mayo Clinic,
Jacksonville, Florida
32224, USA
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic,
Jacksonville, Florida
32224, USA
| | - Jacqueline C. Mitchell
- Clinical Neurosciences, Institute of Psychiatry, Kings
College London, London
SE5 8AF, UK
| | - Christopher E. Shaw
- Clinical Neurosciences, Institute of Psychiatry, Kings
College London, London
SE5 8AF, UK
| | - Christopher C. J. Miller
- Department of Neuroscience, Institute of Psychiatry, Kings
College London, London
SE5 8AF, UK
- Clinical Neurosciences, Institute of Psychiatry, Kings
College London, London
SE5 8AF, UK
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183
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Naon D, Scorrano L. At the right distance: ER-mitochondria juxtaposition in cell life and death. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2184-94. [PMID: 24875902 DOI: 10.1016/j.bbamcr.2014.05.011] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 05/18/2014] [Accepted: 05/19/2014] [Indexed: 11/29/2022]
Abstract
The interface between mitochondria and the endoplasmic reticulum is emerging as a crucial hub for calcium signalling, apoptosis, autophagy and lipid biosynthesis, with far reaching implications in cell life and death and in the regulation of mitochondrial and endoplasmic reticulum function. Here we review our current knowledge on the structural and functional aspects of this interorganellar juxtaposition. This article is part of a Special Issue entitled: Calcium Signaling In Health and Disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.
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Affiliation(s)
- Deborah Naon
- Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine, Via Orus 2, 35129 Padua, Italy; Department of Biology, University of Padua, Via G. Colombo 3, 35121 Padua, Italy
| | - Luca Scorrano
- Dulbecco-Telethon Institute, Venetian Institute of Molecular Medicine, Via Orus 2, 35129 Padua, Italy; Department of Biology, University of Padua, Via G. Colombo 3, 35121 Padua, Italy.
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184
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Zeidán-Chuliá F, de Oliveira BHN, Salmina AB, Casanova MF, Gelain DP, Noda M, Verkhratsky A, Moreira JCF. Altered expression of Alzheimer's disease-related genes in the cerebellum of autistic patients: a model for disrupted brain connectome and therapy. Cell Death Dis 2014; 5:e1250. [PMID: 24853428 PMCID: PMC4047885 DOI: 10.1038/cddis.2014.227] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/13/2014] [Accepted: 04/16/2014] [Indexed: 11/09/2022]
Abstract
Autism and Alzheimer's disease (AD) are, respectively, neurodevelopmental and degenerative diseases with an increasing epidemiological burden. The AD-associated amyloid-β precursor protein-α has been shown to be elevated in severe autism, leading to the 'anabolic hypothesis' of its etiology. Here we performed a focused microarray analysis of genes belonging to NOTCH and WNT signaling cascades, as well as genes related to AD and apoptosis pathways in cerebellar samples from autistic individuals, to provide further evidence for pathological relevance of these cascades for autism. By using the limma package from R and false discovery rate, we demonstrated that 31% (116 out of 374) of the genes belonging to these pathways displayed significant changes in expression (corrected P-values <0.05), with mitochondria-related genes being the most downregulated. We also found upregulation of GRIN1, the channel-forming subunit of NMDA glutamate receptors, and MAP3K1, known activator of the JNK and ERK pathways with anti-apoptotic effect. Expression of PSEN2 (presinilin 2) and APBB1 (or F65) were significantly lower when compared with control samples. Based on these results, we propose a model of NMDA glutamate receptor-mediated ERK activation of α-secretase activity and mitochondrial adaptation to apoptosis that may explain the early brain overgrowth and disruption of synaptic plasticity and connectome in autism. Finally, systems pharmacology analyses of the model that integrates all these genes together (NOWADA) highlighted magnesium (Mg(2+)) and rapamycin as most efficient drugs to target this network model in silico. Their potential therapeutic application, in the context of autism, is therefore discussed.
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Affiliation(s)
- F Zeidán-Chuliá
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - B-H N de Oliveira
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - A B Salmina
- Department of Biochemistry, Medical, Pharmaceutical and Toxicological Chemistry, Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - M F Casanova
- Department of Psychiatry and Behavioral Sciences, University of Louisville, Louisville, KY, USA
| | - D P Gelain
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - M Noda
- Laboratory of Pathophysiology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - A Verkhratsky
- 1] Faculty of Life Sciences, The University of Manchester, Manchester, UK [2] IKERBASQUE, Basque Foundation for Science, Bilbao, Spain [3] Department of Neurosciences, University of the Basque Country UPV/EHU, Leioa, Spain
| | - J C F Moreira
- Centro de Estudos em Estresse Oxidativo, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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185
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Kovacs GG, Adle-Biassette H, Milenkovic I, Cipriani S, van Scheppingen J, Aronica E. Linking pathways in the developing and aging brain with neurodegeneration. Neuroscience 2014; 269:152-72. [PMID: 24699227 DOI: 10.1016/j.neuroscience.2014.03.045] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 03/21/2014] [Accepted: 03/21/2014] [Indexed: 12/12/2022]
Abstract
The molecular and cellular mechanisms, which coordinate the critical stages of brain development to reach a normal structural organization with appropriate networks, are progressively being elucidated. Experimental and clinical studies provide evidence of the occurrence of developmental alterations induced by genetic or environmental factors leading to the formation of aberrant networks associated with learning disabilities. Moreover, evidence is accumulating that suggests that also late-onset neurological disorders, even Alzheimer's disease, might be considered disorders of aberrant neural development with pathological changes that are set up at early stages of development before the appearance of the symptoms. Thus, evaluating proteins and pathways that are important in age-related neurodegeneration in the developing brain together with the characterization of mechanisms important during brain development with relevance to brain aging are of crucial importance. In the present review we focus on (1) aspects of neurogenesis with relevance to aging; (2) neurodegenerative disease (NDD)-associated proteins/pathways in the developing brain; and (3) further pathways of the developing or neurodegenerating brains that show commonalities. Elucidation of complex pathogenetic routes characterizing the earliest stage of the detrimental processes that result in pathological aging represents an essential first step toward a therapeutic intervention which is able to reverse these pathological processes and prevent the onset of the disease. Based on the shared features between pathways, we conclude that prevention of NDDs of the elderly might begin during the fetal and childhood life by providing the mothers and their children a healthy environment for the fetal and childhood development.
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Affiliation(s)
- G G Kovacs
- Institute of Neurology, Medical University of Vienna, Austria.
| | - H Adle-Biassette
- Inserm U1141, F-75019 Paris, France; Univ Paris Diderot, Sorbonne Paris Cité, UMRS 676, F-75019 Paris, France; Department of Pathology, Lariboisière Hospital, APHP, Paris, France
| | - I Milenkovic
- Institute of Neurology, Medical University of Vienna, Austria
| | | | - J van Scheppingen
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, The Netherlands
| | - E Aronica
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, The Netherlands; SEIN - Stichting Epilepsie Instellingen Nederland, Heemstede, The Netherlands; Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, The Netherlands
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186
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van Vliet AR, Verfaillie T, Agostinis P. New functions of mitochondria associated membranes in cellular signaling. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2253-62. [PMID: 24642268 DOI: 10.1016/j.bbamcr.2014.03.009] [Citation(s) in RCA: 265] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 02/12/2014] [Accepted: 03/09/2014] [Indexed: 12/19/2022]
Abstract
In all eukaryotic cells, the endoplasmic reticulum (ER) and the mitochondria establish a tight interplay, which is structurally and functionally modulated through a proteinaceous tether formed at specific subdomains of the ER membrane, designated mitochondria-associated membranes or MAMs. The tethering function of the MAMs allows the regulation of lipid synthesis and rapid transmission of calcium (Ca(2+)) signals between the ER and mitochondria, which is crucial to shape intracellular Ca(2+) signaling and regulate mitochondrial bioenergetics. Research on the molecular characterization and function of MAMs has boomed in the last few years and the list of signaling and structural proteins dynamically associated with the ER-mitochondria contact sites in physiological and pathological conditions, is rapidly increasing along with the realization of an unprecedented complexity underlying the functional role of MAMs. Besides their established role as a signaling hub for Ca(2+) and lipid transfer between ER and mitochondria, MAMs have been recently shown to regulate mitochondrial shape and motility, energy metabolism and redox status and to be central to the modulation of various key processes like ER stress, autophagy and inflammasome signaling. In this review we will discuss some emerging cell-autonomous and cell non-autonomous roles of the MAMs in mammalian cells and their relevance for important human diseases. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.
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Affiliation(s)
- Alexander R van Vliet
- Laboratory of Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, KU Leuven, Leuven B-3000, Belgium
| | - Tom Verfaillie
- Laboratory of Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, KU Leuven, Leuven B-3000, Belgium
| | - Patrizia Agostinis
- Laboratory of Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, KU Leuven, Leuven B-3000, Belgium.
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187
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Sanmartín CD, Paula-Lima AC, García A, Barattini P, Hartel S, Núñez MT, Hidalgo C. Ryanodine receptor-mediated Ca(2+) release underlies iron-induced mitochondrial fission and stimulates mitochondrial Ca(2+) uptake in primary hippocampal neurons. Front Mol Neurosci 2014; 7:13. [PMID: 24653672 PMCID: PMC3949220 DOI: 10.3389/fnmol.2014.00013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 02/03/2014] [Indexed: 01/11/2023] Open
Abstract
Mounting evidence indicates that iron accumulation impairs brain function. We have reported previously that addition of sub-lethal concentrations of iron to primary hippocampal neurons produces Ca2+ signals and promotes cytoplasmic generation of reactive oxygen species. These Ca2+ signals, which emerge within seconds after iron addition, arise mostly from Ca2+ release through the redox-sensitive ryanodine receptor (RyR) channels present in the endoplasmic reticulum. We have reported also that addition of synaptotoxic amyloid-β oligomers to primary hippocampal neurons stimulates RyR-mediated Ca2+ release, generating long-lasting Ca2+ signals that activate Ca2+-sensitive cellular effectors and promote the disruption of the mitochondrial network. Here, we describe that 24 h incubation of primary hippocampal neurons with iron enhanced agonist-induced RyR-mediated Ca2+ release and promoted mitochondrial network fragmentation in 43% of neurons, a response significantly prevented by RyR inhibition and by the antioxidant agent N-acetyl-L-cysteine. Stimulation of RyR-mediated Ca2+ release by a RyR agonist promoted mitochondrial Ca2+ uptake in control neurons and in iron-treated neurons that displayed non-fragmented mitochondria, but not in neurons with fragmented mitochondria. Yet, the global cytoplasmic Ca2+ increase induced by the Ca2+ ionophore ionomycin prompted significant mitochondrial Ca2+ uptake in neurons with fragmented mitochondria, indicating that fragmentation did not prevent mitochondrial Ca2+ uptake but presumably decreased the functional coupling between RyR-mediated Ca2+ release and the mitochondrial Ca2+ uniporter. Taken together, our results indicate that stimulation of redox-sensitive RyR-mediated Ca2+ release by iron causes significant neuronal mitochondrial fragmentation, which presumably contributes to the impairment of neuronal function produced by iron accumulation.
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Affiliation(s)
- Carol D Sanmartín
- Center for Molecular Studies of the Cell, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile Santiago, Chile ; Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile Santiago, Chile
| | - Andrea C Paula-Lima
- Center for Molecular Studies of the Cell, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile Santiago, Chile ; Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile Santiago, Chile ; Institute for Research in Dental Sciences, Faculty of Dentistry, Universidad de Chile Santiago, Chile
| | - Alejandra García
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile Santiago, Chile
| | - Pablo Barattini
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile Santiago, Chile
| | - Steffen Hartel
- Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile Santiago, Chile ; Laboratory of Scientific Image Processing, Anatomy and Developmental Biology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile Santiago, Chile
| | - Marco T Núñez
- Department of Biology, Faculty of Sciences and Research Ring on Oxidative Stress in the Nervous System, Universidad de Chile Santiago, Chile
| | - Cecilia Hidalgo
- Center for Molecular Studies of the Cell, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile Santiago, Chile ; Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile Santiago, Chile ; Physiology and Biophysics Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile Santiago, Chile
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188
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Sepulveda-Falla D, Barrera-Ocampo A, Hagel C, Korwitz A, Vinueza-Veloz MF, Zhou K, Schonewille M, Zhou H, Velazquez-Perez L, Rodriguez-Labrada R, Villegas A, Ferrer I, Lopera F, Langer T, De Zeeuw CI, Glatzel M. Familial Alzheimer's disease-associated presenilin-1 alters cerebellar activity and calcium homeostasis. J Clin Invest 2014; 124:1552-67. [PMID: 24569455 DOI: 10.1172/jci66407] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 12/19/2013] [Indexed: 12/24/2022] Open
Abstract
Familial Alzheimer's disease (FAD) is characterized by autosomal dominant heritability and early disease onset. Mutations in the gene encoding presenilin-1 (PS1) are found in approximately 80% of cases of FAD, with some of these patients presenting cerebellar damage with amyloid plaques and ataxia with unclear pathophysiology. A Colombian kindred carrying the PS1-E280A mutation is the largest known cohort of PS1-FAD patients. Here, we investigated PS1-E280A-associated cerebellar dysfunction and found that it occurs early in PS1-E208A carriers, while cerebellar signs are highly prevalent in patients with dementia. Postmortem analysis of cerebella of PS1-E280A carrier revealed greater Purkinje cell (PC) loss and more abnormal mitochondria compared with controls. In PS1-E280A tissue, ER/mitochondria tethering was impaired, Ca2+ channels IP3Rs and CACNA1A were downregulated, and Ca2+-dependent mitochondrial transport proteins MIRO1 and KIF5C were reduced. Accordingly, expression of PS1-E280A in a neuronal cell line altered ER/mitochondria tethering and transport compared with that in cells expressing wild-type PS1. In a murine model of PS1-FAD, animals exhibited mild ataxia and reduced PC simple spike activity prior to cerebellar β-amyloid deposition. Our data suggest that impaired calcium homeostasis and mitochondrial dysfunction in PS1-FAD PCs reduces their activity and contributes to motor coordination deficits prior to Aβ aggregation and dementia. We propose that PS1-E280A affects both Ca2+ homeostasis and Aβ precursor processing, leading to FAD and neurodegeneration.
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189
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Rivabene R, Visentin S, Piscopo P, De Nuccio C, Crestini A, Svetoni F, Rosa P, Confaloni A. Thapsigargin affects presenilin-2 but not presenilin-1 regulation in SK-N-BE cells. Exp Biol Med (Maywood) 2013; 239:213-24. [PMID: 24363250 DOI: 10.1177/1535370213514317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Presenilin-1 (PS1) and presenilin-2 (PS2) are transmembrane proteins widely expressed in the central nervous system, which function as the catalytic subunits of γ-secretase, the enzyme that releases amyloid-β protein (Aβ) from ectodomain cleaved amyloid precursor protein (APP) by intramembrane proteolysis. Mutations in PS1, PS2, and Aβ protein precursor are involved in the etiology of familial Alzheimer's disease (FAD), while the cause of the sporadic form of AD (SAD) is still not known. However, since similar neuropathological changes have been observed in both FAD and SAD, a common pathway in the etiology of the disease has been suggested. Given that age-related deranged Ca(2+) regulation has been hypothesized to play a role in SAD pathogenesis via PS gene regulation and γ-secretase activity, we studied the in vitro regulation of PS1 and PS2 in the human neuron-like SK-N-BE cell line treated with the specific endoplasmic reticulum (ER) calcium ATPase inhibitor Thapsigargin (THG), to introduce intracellular Ca(2+) perturbations and mimic the altered Ca(2+) homeostasis observed in AD. Our results showed a consistent and significant down-regulation of PS2, while PS1 appeared to be unmodulated. These events were accompanied by oxidative stress and a number of morphological alterations suggestive of the induction of apoptotic machinery. The administration of the antioxidant N-acetylcysteine (NAC) did not revert the THG-induced effects reported, while treatment with the Ca(2+)-independent ER stressor Brefeldin A did not modulate basal PS1 and PS2 expression. Collectively, these results suggest that Ca(2+) fluctuation rather than ER stress and/or oxidative imbalance seems to play an essential role in PS2 regulation and confirm that, despite their strong homology, PS1 and PS2 could play different roles in AD.
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Affiliation(s)
- Roberto Rivabene
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena, 299 00161 Rome, Italy
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190
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Loss-of-function mutations in MICU1 cause a brain and muscle disorder linked to primary alterations in mitochondrial calcium signaling. Nat Genet 2013; 46:188-93. [PMID: 24336167 DOI: 10.1038/ng.2851] [Citation(s) in RCA: 274] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Accepted: 11/20/2013] [Indexed: 12/12/2022]
Abstract
Mitochondrial Ca(2+) uptake has key roles in cell life and death. Physiological Ca(2+) signaling regulates aerobic metabolism, whereas pathological Ca(2+) overload triggers cell death. Mitochondrial Ca(2+) uptake is mediated by the Ca(2+) uniporter complex in the inner mitochondrial membrane, which comprises MCU, a Ca(2+)-selective ion channel, and its regulator, MICU1. Here we report mutations of MICU1 in individuals with a disease phenotype characterized by proximal myopathy, learning difficulties and a progressive extrapyramidal movement disorder. In fibroblasts from subjects with MICU1 mutations, agonist-induced mitochondrial Ca(2+) uptake at low cytosolic Ca(2+) concentrations was increased, and cytosolic Ca(2+) signals were reduced. Although resting mitochondrial membrane potential was unchanged in MICU1-deficient cells, the mitochondrial network was severely fragmented. Whereas the pathophysiology of muscular dystrophy and the core myopathies involves abnormal mitochondrial Ca(2+) handling, the phenotype associated with MICU1 deficiency is caused by a primary defect in mitochondrial Ca(2+) signaling, demonstrating the crucial role of mitochondrial Ca(2+) uptake in humans.
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191
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MAM (mitochondria-associated membranes) in mammalian cells: lipids and beyond. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:595-609. [PMID: 24316057 DOI: 10.1016/j.bbalip.2013.11.014] [Citation(s) in RCA: 443] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 11/21/2013] [Accepted: 11/27/2013] [Indexed: 12/15/2022]
Abstract
One mechanism by which communication between the endoplasmic reticulum (ER) and mitochondria is achieved is by close juxtaposition between these organelles via mitochondria-associated membranes (MAM). The MAM consist of a region of the ER that is enriched in several lipid biosynthetic enzyme activities and becomes reversibly tethered to mitochondria. Specific proteins are localized, sometimes transiently, in the MAM. Several of these proteins have been implicated in tethering the MAM to mitochondria. In mammalian cells, formation of these contact sites between MAM and mitochondria appears to be required for key cellular events including the transport of calcium from the ER to mitochondria, the import of phosphatidylserine into mitochondria from the ER for decarboxylation to phosphatidylethanolamine, the formation of autophagosomes, regulation of the morphology, dynamics and functions of mitochondria, and cell survival. This review focuses on the functions proposed for MAM in mediating these events in mammalian cells. In light of the apparent involvement of MAM in multiple fundamental cellular processes, recent studies indicate that impaired contact between MAM and mitochondria might underlie the pathology of several human neurodegenerative diseases, including Alzheimer's disease. Moreover, MAM has been implicated in modulating glucose homeostasis and insulin resistance, as well as in some viral infections.
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192
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McBrayer M, Nixon RA. Lysosome and calcium dysregulation in Alzheimer's disease: partners in crime. Biochem Soc Trans 2013; 41:1495-502. [PMID: 24256243 PMCID: PMC3960943 DOI: 10.1042/bst20130201] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Early-onset FAD (familial Alzheimer's disease) is caused by mutations of PS1 (presenilin 1), PS2 (presenilin 2) and APP (amyloid precursor protein). Beyond the effects of PS1 mutations on proteolytic functions of the γ-secretase complex, mutant or deficient PS1 disrupts lysosomal function and Ca2+ homoeostasis, both of which are considered strong pathogenic factors in FAD. Loss of PS1 function compromises assembly and proton-pumping activity of the vacuolar-ATPase on lysosomes, leading to defective lysosomal acidification and marked impairment of autophagy. Additional dysregulation of cellular Ca2+ by mutant PS1 in FAD has been ascribed to altered ion channels in the endoplasmic reticulum; however, rich stores of Ca2+ in lysosomes are also abnormally released in PS1-deficient cells secondary to the lysosomal acidification defect. The resultant rise in cytosolic Ca2+ activates Ca2+-dependent enzymes, contributing substantially to calpain overactivation that is a final common pathway leading to neurofibrillary degeneration in all forms of AD (Alzheimer's disease). In the present review, we discuss the close inter-relationships among deficits of lysosomal function, autophagy and Ca2+ homoeostasis as a pathogenic process in PS1-related FAD and their relevance to sporadic AD.
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Affiliation(s)
- MaryKate McBrayer
- Center for Dementia Research, Nathan S. Kline Institute, 140 Old Orangeburg Road, Orangeburg NY 10962
| | - Ralph A. Nixon
- Center for Dementia Research, Nathan S. Kline Institute, 140 Old Orangeburg Road, Orangeburg NY 10962
- Department of Psychiatry, New York University Langone Medical Center, 550 1 Avenue, New York NY 10016
- Department of Cell Biology, New York University Langone Medical Center, 550 1 Avenue, New York NY 10016
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193
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Marchi S, Patergnani S, Pinton P. The endoplasmic reticulum-mitochondria connection: one touch, multiple functions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:461-9. [PMID: 24211533 DOI: 10.1016/j.bbabio.2013.10.015] [Citation(s) in RCA: 348] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 10/29/2013] [Accepted: 10/31/2013] [Indexed: 12/14/2022]
Abstract
The endoplasmic reticulum (ER) and mitochondria are tubular organelles with a characteristic "network structure" that facilitates the formation of interorganellar connections. The ER and mitochondria join together at multiple contact sites to form specific domains, termed mitochondria-ER associated membranes (MAMs), with distinct biochemical properties and a characteristic set of proteins. The functions of these two organelles are coordinated and executed at the ER-mitochondria interface, which provides a platform for the regulation of different processes. The roles played by the ER-mitochondria interface range from the coordination of calcium transfer to the regulation of mitochondrial fission and inflammasome formation as well as the provision of membranes for autophagy. The novel and unconventional processes that occur at the ER-mitochondria interface demonstrate its multifunctional and intrinsically dynamic nature. This article is part of a Special Issue entitled: Dynamic and ultrastructure of bioenergetic membranes and their components.
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Affiliation(s)
- Saverio Marchi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Interdisciplinary Center for the Study of Inflammation (ICSI), Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy
| | - Simone Patergnani
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Interdisciplinary Center for the Study of Inflammation (ICSI), Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy
| | - Paolo Pinton
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Interdisciplinary Center for the Study of Inflammation (ICSI), Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy.
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194
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Smolarkiewicz M, Skrzypczak T, Wojtaszek P. The very many faces of presenilins and the γ-secretase complex. PROTOPLASMA 2013; 250:997-1011. [PMID: 23504135 PMCID: PMC3788181 DOI: 10.1007/s00709-013-0494-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 03/01/2013] [Indexed: 05/02/2023]
Abstract
Presenilin is a central, catalytic component of the γ-secretase complex which conducts intramembrane cleavage of various protein substrates. Although identified and mainly studied through its role in the development of amyloid plaques in Alzheimer disease, γ-secretase has many other important functions. The complex seems to be evolutionary conserved throughout the Metazoa, but recent findings in plants and Dictyostelium discoideum as well as in archeons suggest that its evolution and functions might be much more diversified than previously expected. In this review, a selective survey of the multitude of functions of presenilins and the γ-secretase complex is presented. Following a brief overview of γ-secretase structure, assembly and maturation, three functional aspects are analyzed: (1) the role of γ-secretase in autophagy and phagocytosis; (2) involvement of the complex in signaling related to endocytosis; and (3) control of calcium fluxes by presenilins.
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Affiliation(s)
- Michalina Smolarkiewicz
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Tomasz Skrzypczak
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Przemysław Wojtaszek
- Department of Molecular and Cellular Biology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
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195
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Száraz P, Bánhegyi G, Marcolongo P, Benedetti A. Transient knockdown of presenilin-1 provokes endoplasmic reticulum stress related formation of autophagosomes in HepG2 cells. Arch Biochem Biophys 2013; 538:57-63. [PMID: 23942054 DOI: 10.1016/j.abb.2013.08.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 07/27/2013] [Accepted: 08/03/2013] [Indexed: 12/01/2022]
Abstract
The involvement of presenilins in the endoplasmic reticulum (ER) related autophagy was investigated by their transient knockdown in HepG2 cells. The silencing of PSEN1 but not of PSEN2 led to cell growth impairment and decreased viability. PSEN1 silencing resulted in ER stress response as evidenced by the elevated levels of glucose regulated protein 78 (Grp78), protein disulfide isomerase (PDI), and CCAAT/enhancer-binding protein homologous protein (CHOP) and by the activation of activating transcription factor 6 (ATF6). The activation of autophagy was indicated by the increased procession of microtubule-associated light chain 3 protein isoform B (LC3B) and by decreased phosphorylation of mammalian target of rapamycin (mTOR) and 70kDa ribosomal protein S6 kinase (p70S6K). Formation of ER-related cytoplasmic vacuolization colocalizing with the autophagic marker LC3B was also observed. The morphological effects and LC3B activation in presenilin-1 knockdown cells could be prevented by using the phosphoinositide 3-kinase (PI3K) inhibitor wortmannin or by calcium chelation. The results show that presenilin-1 hampers the ER stress dependent initiation of macroautophagy.
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Affiliation(s)
- Péter Száraz
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
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196
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Pitts MW, Reeves MA, Hashimoto AC, Ogawa A, Kremer P, Seale LA, Berry MJ. Deletion of selenoprotein M leads to obesity without cognitive deficits. J Biol Chem 2013; 288:26121-26134. [PMID: 23880772 DOI: 10.1074/jbc.m113.471235] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Selenium is an essential trace element that is co-translationally incorporated into selenoproteins in the form of the 21st amino acid, selenocysteine. This class of proteins largely functions in oxidation-reduction reactions and is critically involved in maintaining proper redox balance essential to health. Selenoprotein M (SelM) is a thioredoxin-like endoplasmic reticulum-resident protein that is highly expressed in the brain and possesses neuroprotective properties. In this study, we first assessed the regional pattern of SelM expression in the mouse brain to provide insights into the potential functional implications of this protein in physiology and behavior. Next, we generated transgenic mice with a targeted deletion of the SelM gene and subjected them to a battery of neurobehavioral tests to evaluate motor coordination, locomotion, and cognitive function in comparison with wild-type controls. Finally, these mice were tested for several measures of metabolic function and body composition. Our results show that SelM knock-out (KO) mice display no deficits in measures of motor coordination and cognitive function but exhibit increased weight gain, elevated white adipose tissue deposition, and diminished hypothalamic leptin sensitivity. These findings suggest that SelM plays an important role in the regulation of body weight and energy metabolism.
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Affiliation(s)
- Matthew W Pitts
- From the Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813.
| | - Mariclair A Reeves
- From the Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813
| | - Ann C Hashimoto
- From the Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813
| | - Ashley Ogawa
- From the Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813
| | - Penny Kremer
- From the Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813
| | - Lucia A Seale
- From the Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813
| | - Marla J Berry
- From the Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813
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197
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MITOL Regulates Endoplasmic Reticulum-Mitochondria Contacts via Mitofusin2. Mol Cell 2013; 51:20-34. [DOI: 10.1016/j.molcel.2013.04.023] [Citation(s) in RCA: 211] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 03/29/2013] [Accepted: 04/26/2013] [Indexed: 11/22/2022]
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198
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Wiley SE, Andreyev AY, Divakaruni AS, Karisch R, Perkins G, Wall EA, van der Geer P, Chen YF, Tsai TF, Simon MI, Neel BG, Dixon JE, Murphy AN. Wolfram Syndrome protein, Miner1, regulates sulphydryl redox status, the unfolded protein response, and Ca2+ homeostasis. EMBO Mol Med 2013; 5:904-18. [PMID: 23703906 PMCID: PMC3779451 DOI: 10.1002/emmm.201201429] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Revised: 03/26/2013] [Accepted: 03/27/2013] [Indexed: 01/21/2023] Open
Abstract
Miner1 is a redox-active 2Fe2S cluster protein. Mutations in Miner1 result in Wolfram Syndrome, a metabolic disease associated with diabetes, blindness, deafness, and a shortened lifespan. Embryonic fibroblasts from Miner1(-/-) mice displayed ER stress and showed hallmarks of the unfolded protein response. In addition, loss of Miner1 caused a depletion of ER Ca(2+) stores, a dramatic increase in mitochondrial Ca(2+) load, increased reactive oxygen and nitrogen species, an increase in the GSSG/GSH and NAD(+)/NADH ratios, and an increase in the ADP/ATP ratio consistent with enhanced ATP utilization. Furthermore, mitochondria in fibroblasts lacking Miner1 displayed ultrastructural alterations, such as increased cristae density and punctate morphology, and an increase in O2 consumption. Treatment with the sulphydryl anti-oxidant N-acetylcysteine reversed the abnormalities in the Miner1 deficient cells, suggesting that sulphydryl reducing agents should be explored as a treatment for this rare genetic disease.
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Affiliation(s)
- Sandra E Wiley
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
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199
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Hedskog L, Pinho CM, Filadi R, Rönnbäck A, Hertwig L, Wiehager B, Larssen P, Gellhaar S, Sandebring A, Westerlund M, Graff C, Winblad B, Galter D, Behbahani H, Pizzo P, Glaser E, Ankarcrona M. Modulation of the endoplasmic reticulum-mitochondria interface in Alzheimer's disease and related models. Proc Natl Acad Sci U S A 2013; 110:7916-21. [PMID: 23620518 PMCID: PMC3651455 DOI: 10.1073/pnas.1300677110] [Citation(s) in RCA: 353] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It is well-established that subcompartments of endoplasmic reticulum (ER) are in physical contact with the mitochondria. These lipid raft-like regions of ER are referred to as mitochondria-associated ER membranes (MAMs), and they play an important role in, for example, lipid synthesis, calcium homeostasis, and apoptotic signaling. Perturbation of MAM function has previously been suggested in Alzheimer's disease (AD) as shown in fibroblasts from AD patients and a neuroblastoma cell line containing familial presenilin-2 AD mutation. The effect of AD pathogenesis on the ER-mitochondria interplay in the brain has so far remained unknown. Here, we studied ER-mitochondria contacts in human AD brain and related AD mouse and neuronal cell models. We found uniform distribution of MAM in neurons. Phosphofurin acidic cluster sorting protein-2 and σ1 receptor, two MAM-associated proteins, were shown to be essential for neuronal survival, because siRNA knockdown resulted in degeneration. Up-regulated MAM-associated proteins were found in the AD brain and amyloid precursor protein (APP)Swe/Lon mouse model, in which up-regulation was observed before the appearance of plaques. By studying an ER-mitochondria bridging complex, inositol-1,4,5-triphosphate receptor-voltage-dependent anion channel, we revealed that nanomolar concentrations of amyloid β-peptide increased inositol-1,4,5-triphosphate receptor and voltage-dependent anion channel protein expression and elevated the number of ER-mitochondria contact points and mitochondrial calcium concentrations. Our data suggest an important role of ER-mitochondria contacts and cross-talk in AD pathology.
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Affiliation(s)
- Louise Hedskog
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet-Alzheimer’s Disease Research Center, Karolinska Institutet, 141 86 Stockholm, Sweden
| | - Catarina Moreira Pinho
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
| | - Riccardo Filadi
- Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
| | - Annica Rönnbäck
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet-Alzheimer’s Disease Research Center, Karolinska Institutet, 141 86 Stockholm, Sweden
| | - Laura Hertwig
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet-Alzheimer’s Disease Research Center, Karolinska Institutet, 141 86 Stockholm, Sweden
| | - Birgitta Wiehager
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet-Alzheimer’s Disease Research Center, Karolinska Institutet, 141 86 Stockholm, Sweden
| | - Pia Larssen
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet-Alzheimer’s Disease Research Center, Karolinska Institutet, 141 86 Stockholm, Sweden
| | - Sandra Gellhaar
- Department of Neuroscience, Karolinska Institutet, 171 65 Stockholm, Sweden; and
| | - Anna Sandebring
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet-Alzheimer’s Disease Research Center, Karolinska Institutet, 141 86 Stockholm, Sweden
| | - Marie Westerlund
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet-Alzheimer’s Disease Research Center, Karolinska Institutet, 141 86 Stockholm, Sweden
| | - Caroline Graff
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet-Alzheimer’s Disease Research Center, Karolinska Institutet, 141 86 Stockholm, Sweden
- Genetics Unit, Department of Geriatric Medicine, Karolinska University Hospital, 141 86 Stockholm, Sweden
| | - Bengt Winblad
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet-Alzheimer’s Disease Research Center, Karolinska Institutet, 141 86 Stockholm, Sweden
| | - Dagmar Galter
- Department of Neuroscience, Karolinska Institutet, 171 65 Stockholm, Sweden; and
| | - Homira Behbahani
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet-Alzheimer’s Disease Research Center, Karolinska Institutet, 141 86 Stockholm, Sweden
| | - Paola Pizzo
- Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
| | - Elzbieta Glaser
- Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden
| | - Maria Ankarcrona
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet-Alzheimer’s Disease Research Center, Karolinska Institutet, 141 86 Stockholm, Sweden
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200
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Honarnejad K, Jung CKE, Lammich S, Arzberger T, Kretzschmar H, Herms J. Involvement of presenilin holoprotein upregulation in calcium dyshomeostasis of Alzheimer's disease. J Cell Mol Med 2013; 17:293-302. [PMID: 23379308 PMCID: PMC3822592 DOI: 10.1111/jcmm.12008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 11/29/2012] [Indexed: 12/16/2022] Open
Abstract
Mutations in presenilins (PS1 and PS2) account for the vast majority of early onset familial Alzheimer's disease cases. Beside the well investigated role of presenilins as the catalytic unit in γ-secretase complex, their involvement in regulation of intracellular calcium homeostasis has recently come into more focus of Alzheimer's disease research. Here we report that the overexpression of PS1 full-length holoprotein forms, in particular familial Alzheimer's disease-causing forms of PS1, result in significantly attenuated calcium release from thapsigargin- and bradykinin-sensitive stores. Interestingly, treatment of HEK293 cells with γ-secretase inhibitors also leads to decreased amount of calcium release from endoplasmic reticulum (ER) accompanying elevated PS1 holoprotein levels. Similarly, the knockdown of PEN-2 which is associated with deficient PS1 endoproteolysis and accumulation of its holoprotein form also leads to decreased ER calcium release. Notably, we detected enhanced PS1 holoprotein levels also in postmortem brains of patients carrying familial Alzheimer's disease PS1 mutations. Taken together, the conditions in which the amount of full length PS1 holoprotein is increased result in reduction of calcium release from ER. Based on these results, we propose that the disturbed ER calcium homeostasis mediated by the elevation of PS1 holoprotein levels may be a contributing factor to the pathogenesis of Alzheimer's disease.
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Affiliation(s)
- Kamran Honarnejad
- Department of Translational Brain Research, DZNE - German Center for Neurodegenerative Diseases, Munich, Germany
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