51
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Sun Z, Xie Y, Chen Y, Yang Q, Quan Z, Dai R, Qing H. Rab21, a Novel PS1 Interactor, Regulates γ-Secretase Activity via PS1 Subcellular Distribution. Mol Neurobiol 2017; 55:3841-3855. [PMID: 28547526 DOI: 10.1007/s12035-017-0606-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/08/2017] [Indexed: 01/09/2023]
Abstract
γ-Secretase has been a therapeutical target for its key role in cleaving APP to generate β-amyloid (Aβ), the primary constituents of senile plaques and a hallmark of Alzheimer's disease (AD) pathology. Recently, γ-secretase-associating proteins showed promising role in specifically modulating APP processing while sparing Notch signaling; however, the underlying mechanism is still unclear. A co-immunoprecipitation (Co-IP) coupled with mass spectrometry proteomic assay for Presenilin1 (PS1, the catalytic subunit of γ-secretase) was firstly conducted to find more γ-secretase-associating proteins. Gene ontology analysis of these results identified Rab21 as a potential PS1 interacting protein, and the interaction between them was validated by reciprocal Co-IP and immunofluorescence assay. Then, molecular and biochemical methods were used to investigate the effect of Rab21 on APP processing. Results showed that overexpression of Rab21 enhanced Aβ generation, while silencing of Rab21 reduced the accumulation of Aβ, which resulted due to change in γ-secretase activity rather than α- or β-secretase. Finally, we demonstrated that Rab21 had no effect on γ-secretase complex synthesis or metabolism but enhanced PS1 endocytosis and translocation to late endosome/lysosome. In conclusion, we identified a novel γ-secretase-associating protein Rab21 and illustrate that Rab21 promotes γ-secretase internalization and translocation to late endosome/lysosome. Moreover, silencing of Rab21 decreases the γ-secretase activity in APP processing thus production of Aβ. All these results open new gateways towards the understanding of γ-secretase-associating proteins in APP processing and make inhibition of Rab21 a promising strategy for AD therapy.
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Affiliation(s)
- Zhenzhen Sun
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, People's Republic of China
| | - Yujie Xie
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, People's Republic of China
| | - Yintong Chen
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, People's Republic of China
| | - Qinghu Yang
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, People's Republic of China
| | - Zhenzhen Quan
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, People's Republic of China
| | - Rongji Dai
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, People's Republic of China
| | - Hong Qing
- School of Life Science, Beijing Institute of Technology, Beijing, 100081, People's Republic of China.
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52
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Kemmerling N, Wunderlich P, Theil S, Linnartz-Gerlach B, Hersch N, Hoffmann B, Heneka MT, de Strooper B, Neumann H, Walter J. Intramembranous processing by γ-secretase regulates reverse signaling of ephrin-B2 in migration of microglia. Glia 2017; 65:1103-1118. [PMID: 28370426 DOI: 10.1002/glia.23147] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 03/14/2017] [Accepted: 03/16/2017] [Indexed: 12/30/2022]
Abstract
The Eph-ephrin system plays pivotal roles in cell adhesion and migration. The receptor-like functions of the ephrin ligands allow the regulation of intracellular processes via reverse signaling. γ-Secretase mediated processing of ephrin-B has previously been linked to activation of Src, a kinase crucial for focal adhesion and podosome phosphorylation. Here, we analyzed the role of γ-secretase in the stimulation of reverse ephrin-B2 signaling in the migration of mouse embryonic stem cell derived microglia. The proteolytic generation of the ephrin-B2 intracellular domain (ICD) by γ-secretase stimulates Src and focal adhesion kinase (FAK). Inhibition of γ-secretase decreased the phosphorylation of Src and FAK, and reduced cell motility. These effects were associated with enlargement of the podosomal surface. Interestingly, expression of ephrin-B2 ICD could rescue these effects, indicating that this proteolytic fragment mediates the activation of Src and FAK, and thereby regulates podosomal dynamics in microglial cells. Together, these results identify γ-secretase as well as ephrin-B2 as regulators of microglial migration.
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Affiliation(s)
- Nadja Kemmerling
- Department of Neurology, University of Bonn, Bonn, 53127, Germany
| | | | - Sandra Theil
- Department of Neurology, University of Bonn, Bonn, 53127, Germany
| | | | - Nils Hersch
- Institute of Complex Systems, ICS-7 Biomechanics, Forschungszentrum Jülich GmbH, Jülich, 52425, Germany
| | - Bernd Hoffmann
- Institute of Complex Systems, ICS-7 Biomechanics, Forschungszentrum Jülich GmbH, Jülich, 52425, Germany
| | - Michael T Heneka
- Department of Neurology, University of Bonn, Bonn, 53127, Germany.,German Center for Neurodegenerative Diseases, Bonn, 53127, Germany
| | - Bart de Strooper
- KULeuven Centre for Human Genetics, Leuven, 3000, Belgium.,Centre for Brain and Disease, VIB (Flanders Institute for Biotechnology), Leuven, 3000, Belgium
| | - Harald Neumann
- Institute of Reconstructive Neurobiology, University of Bonn, Bonn, 53127, Germany
| | - Jochen Walter
- Department of Neurology, University of Bonn, Bonn, 53127, Germany
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53
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Management of Alzheimer’s disease—An insight of the enzymatic and other novel potential targets. Int J Biol Macromol 2017; 97:700-709. [DOI: 10.1016/j.ijbiomac.2017.01.076] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/15/2017] [Accepted: 01/16/2017] [Indexed: 12/25/2022]
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54
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González AE, Muñoz VC, Cavieres VA, Bustamante HA, Cornejo VH, Januário YC, González I, Hetz C, daSilva LL, Rojas-Fernández A, Hay RT, Mardones GA, Burgos PV. Autophagosomes cooperate in the degradation of intracellular C-terminal fragments of the amyloid precursor protein via the MVB/lysosomal pathway. FASEB J 2017; 31:2446-2459. [PMID: 28254759 DOI: 10.1096/fj.201600713r] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 02/07/2017] [Indexed: 12/14/2022]
Abstract
Brain regions affected by Alzheimer disease (AD) display well-recognized early neuropathologic features in the endolysosomal and autophagy systems of neurons, including enlargement of endosomal compartments, progressive accumulation of autophagic vacuoles, and lysosomal dysfunction. Although the primary causes of these disturbances are still under investigation, a growing body of evidence suggests that the amyloid precursor protein (APP) intracellular C-terminal fragment β (C99), generated by cleavage of APP by β-site APP cleaving enzyme 1 (BACE-1), is the primary cause of the endosome enlargement in AD and the earliest initiator of synaptic plasticity and long-term memory impairment. The aim of the present study was to evaluate the possible relationship between the endolysosomal degradation pathway and autophagy on the proteolytic processing and turnover of C99. We found that pharmacologic treatments that either inhibit autophagosome formation or block the fusion of autophagosomes to endolysosomal compartments caused an increase in C99 levels. We also found that inhibition of autophagosome formation by depletion of Atg5 led to higher levels of C99 and to its massive accumulation in the lumen of enlarged perinuclear, lysosomal-associated membrane protein 1 (LAMP1)-positive organelles. In contrast, activation of autophagosome formation, either by starvation or by inhibition of the mammalian target of rapamycin, enhanced lysosomal clearance of C99. Altogether, our results indicate that autophagosomes are key organelles to help avoid C99 accumulation preventing its deleterious effects.-González, A. E., Muñoz, V. C., Cavieres, V. A., Bustamante, H. A., Cornejo, V.-H., Januário, Y. C., González, I., Hetz, C., daSilva, L. L., Rojas-Fernández, A., Hay, R. T., Mardones, G. A., Burgos, P. V. Autophagosomes cooperate in the degradation of intracellular C-terminal fragments of the amyloid precursor protein via the MVB/lysosomal pathway.
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Affiliation(s)
- Alexis E González
- Department of Physiology, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Vanessa C Muñoz
- Department of Physiology, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Viviana A Cavieres
- Department of Physiology, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Hianara A Bustamante
- Department of Physiology, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Víctor-Hugo Cornejo
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile.,Center for Geroscience, Brain Health and Metabolism, Santiago, Chile
| | - Yunan C Januário
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Ibeth González
- Department of Physiology, School of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Claudio Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile.,Center for Geroscience, Brain Health and Metabolism, Santiago, Chile.,Buck Institute for Research on Aging, Novato, California, USA.,Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachussets, USA
| | - Luis L daSilva
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Alejandro Rojas-Fernández
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom.,Center for Interdisciplinary Studies of the Nervous System (CISNe), Universidad Austral de Chile, Valdivia, Chile
| | - Ronald T Hay
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Gonzalo A Mardones
- Department of Physiology, School of Medicine, Universidad Austral de Chile, Valdivia, Chile.,Center for Interdisciplinary Studies of the Nervous System (CISNe), Universidad Austral de Chile, Valdivia, Chile
| | - Patricia V Burgos
- Department of Physiology, School of Medicine, Universidad Austral de Chile, Valdivia, Chile; .,Center for Interdisciplinary Studies of the Nervous System (CISNe), Universidad Austral de Chile, Valdivia, Chile
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55
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Affiliation(s)
- Rodrigo Aguayo-Ortiz
- Departamento de Fisicoquímica; Universidad Nacional Autónoma de México; Ciudad de México 04510 México
| | - Laura Dominguez
- Departamento de Fisicoquímica; Universidad Nacional Autónoma de México; Ciudad de México 04510 México
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56
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A Presenilin/Notch1 pathway regulated by miR-375, miR-30a, and miR-34a mediates glucotoxicity induced-pancreatic beta cell apoptosis. Sci Rep 2016; 6:36136. [PMID: 27804997 PMCID: PMC5095347 DOI: 10.1038/srep36136] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 10/11/2016] [Indexed: 02/07/2023] Open
Abstract
The presenilin-mediated Notch1 cleavage pathway plays a critical role in controlling pancreatic beta cell fate and survival. The aim of the present study was to investigate the role of Notch1 activation in glucotoxicity-induced beta cell impairment and the contributions of miR-375, miR-30a, and miR-34a to this pathway. We found that the protein levels of presenilins (PSEN1 and PSEN2), and NOTCH1 were decreased in INS-1 cells after treatment with increased concentrations of glucose, whereas no significant alteration of mRNA level of Notch1 was observed. Targeting of miR-375, miR-30a, and miR-34a to the 3′utr of Psen1, Psen2, and Notch1, respectively, reduced the amounts of relevant proteins, thereby reducing NICD1 amounts and causing beta cell apoptosis. Overexpression of NICD1 blocked the effects of glucotoxicity as well as miRNA overabundance. Downregulating the expression of miR-375, miR-30a, and miR-34a restored PSEN1, PSEN2, and NICD1 production and prevented glucotoxicity-induced impairment of the beta cells. These patterns of miRNA regulation of the Notch1 cleavage pathway were reproduced in GK rats as well as in aged rats. Our findings demonstrated that miRNA-mediated suppression of NICD1 links the presenilin/Notch1 pathway to glucotoxicity in mature pancreatic beta cells.
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57
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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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58
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Restricted Location of PSEN2/γ-Secretase Determines Substrate Specificity and Generates an Intracellular Aβ Pool. Cell 2016; 166:193-208. [PMID: 27293189 DOI: 10.1016/j.cell.2016.05.020] [Citation(s) in RCA: 219] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/06/2016] [Accepted: 04/28/2016] [Indexed: 01/07/2023]
Abstract
γ-Secretases are a family of intramembrane-cleaving proteases involved in various signaling pathways and diseases, including Alzheimer's disease (AD). Cells co-express differing γ-secretase complexes, including two homologous presenilins (PSENs). We examined the significance of this heterogeneity and identified a unique motif in PSEN2 that directs this γ-secretase to late endosomes/lysosomes via a phosphorylation-dependent interaction with the AP-1 adaptor complex. Accordingly, PSEN2 selectively cleaves late endosomal/lysosomal localized substrates and generates the prominent pool of intracellular Aβ that contains longer Aβ; familial AD (FAD)-associated mutations in PSEN2 increased the levels of longer Aβ further. Moreover, a subset of FAD mutants in PSEN1, normally more broadly distributed in the cell, phenocopies PSEN2 and shifts its localization to late endosomes/lysosomes. Thus, localization of γ-secretases determines substrate specificity, while FAD-causing mutations strongly enhance accumulation of aggregation-prone Aβ42 in intracellular acidic compartments. The findings reveal potentially important roles for specific intracellular, localized reactions contributing to AD pathogenesis.
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59
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Venne AS, Solari FA, Faden F, Paretti T, Dissmeyer N, Zahedi RP. An improved workflow for quantitative N-terminal charge-based fractional diagonal chromatography (ChaFRADIC) to study proteolytic events in Arabidopsis thaliana. Proteomics 2016; 15:2458-69. [PMID: 26010716 DOI: 10.1002/pmic.201500014] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 04/28/2015] [Accepted: 05/20/2015] [Indexed: 11/11/2022]
Abstract
We applied an extended charge-based fractional diagonal chromatography (ChaFRADIC) workflow to analyze the N-terminal proteome of Arabidopsis thaliana seedlings. Using iTRAQ protein labeling and a multi-enzyme digestion approach including trypsin, GluC, and subtilisin, a total of 200 μg per enzyme, and measuring only one third of each ChaFRADIC-enriched fraction by LC-MS, we quantified a total of 2791 unique N-terminal peptides corresponding to 2249 different unique N-termini from 1270 Arabidopsis proteins. Our data indicate the power, reproducibility, and sensitivity of the applied strategy that might be applicable to quantify proteolytic events from as little as 20 μg of protein per condition across up to eight different samples. Furthermore, our data clearly reflect the methionine excision dogma as well as the N-end rule degradation pathway (NERP) discriminating into a stabilizing or destabilizing function of N-terminal amino acid residues. We found bona fide NERP destabilizing residues underrepresented, and the list of neo N-termini from wild type samples may represent a helpful resource during the evaluation of NERP substrate candidates. All MS data have been deposited in the ProteomeXchange with identifier PXD001855 (http://proteomecentral.proteomexchange.org/dataset/PXD001855).
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Affiliation(s)
- A Saskia Venne
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V, Dortmund, Germany
| | - Fiorella A Solari
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V, Dortmund, Germany
| | - Frederik Faden
- Leibniz Institute of Plant Biochemistry (IPB), Halle (Saale), Germany.,ScienceCampus Halle - Plant-Based Bioeconomy, Halle (Saale), Germany
| | - Tomasso Paretti
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V, Dortmund, Germany.,Department of Molecular Medicine, Institute of Biochemistry, University of Pavia, Italy
| | - Nico Dissmeyer
- Leibniz Institute of Plant Biochemistry (IPB), Halle (Saale), Germany.,ScienceCampus Halle - Plant-Based Bioeconomy, Halle (Saale), Germany
| | - René P Zahedi
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V, Dortmund, Germany
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60
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Elad N, De Strooper B, Lismont S, Hagen W, Veugelen S, Arimon M, Horré K, Berezovska O, Sachse C, Chávez-Gutiérrez L. The dynamic conformational landscape of gamma-secretase. J Cell Sci 2016; 128:589-98. [PMID: 25501811 PMCID: PMC4311135 DOI: 10.1242/jcs.164384] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The structure and function of the gamma-secretase proteases are of great interest because of their crucial roles in cellular and disease processes. We established a novel purification protocol for the gamma-secretase complex that involves a conformation- and complex-specific nanobody, yielding highly pure and active enzyme. Using single particle electron microscopy, we analyzed the gamma-secretase structure and its conformational variability. Under steady-state conditions, the complex adopts three major conformations, which differ in overall compactness and relative position of the nicastrin ectodomain. Occupancy of the active or substrate-binding sites by inhibitors differentially stabilizes subpopulations of particles with compact conformations, whereas a mutation linked to familial Alzheimer disease results in enrichment of extended-conformation complexes with increased flexibility. Our study presents the csecretase complex as a dynamic population of interconverting conformations, involving rearrangements at the nanometer scale and a high level of structural interdependence between subunits. The fact that protease inhibition or clinical mutations, which affect amyloid beta (Abeta) generation, enrich for particular subpopulations of conformers indicates the functional relevance of the observed dynamic changes, which are likely to be instrumental for highly allosteric behavior of the enzyme.
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Affiliation(s)
- Nadav Elad
- VIB Center for the Biology of Disease, 3000 Leuven, Belgium
- Center of Human Genetics, University Hospitals Leuven & Department of Human Genetics, KU Leuven, and Leuven Research Institute for Neuroscience and Disease (LIND), 3000 Leuven, Belgium
| | - Bart De Strooper
- VIB Center for the Biology of Disease, 3000 Leuven, Belgium
- Center of Human Genetics, University Hospitals Leuven & Department of Human Genetics, KU Leuven, and Leuven Research Institute for Neuroscience and Disease (LIND), 3000 Leuven, Belgium
- UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
- Authors for correspondence (; ; )
| | - Sam Lismont
- VIB Center for the Biology of Disease, 3000 Leuven, Belgium
- Center of Human Genetics, University Hospitals Leuven & Department of Human Genetics, KU Leuven, and Leuven Research Institute for Neuroscience and Disease (LIND), 3000 Leuven, Belgium
| | - Wim Hagen
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Meyerhofstrasse1, 69117 Heidelberg, Germany
| | - Sarah Veugelen
- VIB Center for the Biology of Disease, 3000 Leuven, Belgium
- Center of Human Genetics, University Hospitals Leuven & Department of Human Genetics, KU Leuven, and Leuven Research Institute for Neuroscience and Disease (LIND), 3000 Leuven, Belgium
| | - Muriel Arimon
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Katrien Horré
- VIB Center for the Biology of Disease, 3000 Leuven, Belgium
- Center of Human Genetics, University Hospitals Leuven & Department of Human Genetics, KU Leuven, and Leuven Research Institute for Neuroscience and Disease (LIND), 3000 Leuven, Belgium
| | - Oksana Berezovska
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Meyerhofstrasse1, 69117 Heidelberg, Germany
| | - Carsten Sachse
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, Meyerhofstrasse1, 69117 Heidelberg, Germany
- Authors for correspondence (; ; )
| | - Lucía Chávez-Gutiérrez
- VIB Center for the Biology of Disease, 3000 Leuven, Belgium
- Center of Human Genetics, University Hospitals Leuven & Department of Human Genetics, KU Leuven, and Leuven Research Institute for Neuroscience and Disease (LIND), 3000 Leuven, Belgium
- Authors for correspondence (; ; )
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61
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Jung S, Nah J, Han J, Choi SG, Kim H, Park J, Pyo HK, Jung YK. Dual-specificity phosphatase 26 (DUSP26) stimulates Aβ42 generation by promoting amyloid precursor protein axonal transport during hypoxia. J Neurochem 2016; 137:770-81. [PMID: 26924229 DOI: 10.1111/jnc.13597] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/29/2016] [Accepted: 02/16/2016] [Indexed: 12/23/2022]
Abstract
Amyloid beta peptide (Aβ) is a pathological hallmark of Alzheimer's disease (AD) and is generated through the sequential cleavage of amyloid precursor protein (APP) by β- and γ-secretases. Hypoxia is a known risk factor for AD and stimulates Aβ generation by γ-secretase; however, the underlying mechanisms remain unclear. In this study, we showed that dual-specificity phosphatase 26 (DUSP26) regulates Aβ generation through changes in subcellular localization of the γ-secretase complex and its substrate C99 under hypoxic conditions. DUSP26 was identified as a novel γ-secretase regulator from a genome-wide functional screen using a cDNA expression library. The phosphatase activity of DUSP26 was required for the increase in Aβ42 generation through γ-secretase, but this regulation did not affect the amount of the γ-secretase complex. Interestingly, DUSP26 induced the accumulation of C99 in the axons by stimulating anterograde transport of C99-positive vesicles. Additionally, DUSP26 induced c-Jun N-terminal kinase (JNK) activation for APP processing and axonal transport of C99. Under hypoxic conditions, DUSP26 expression levels were elevated together with JNK activation, and treatment with JNK inhibitor SP600125, or the DUSP26 inhibitor NSC-87877, reduced hypoxia-induced Aβ generation by diminishing vesicle trafficking of C99 to the axons. Finally, we observed enhanced DUSP26 expression and JNK activation in the hippocampus of AD patients. Our results suggest that DUSP26 mediates hypoxia-induced Aβ generation through JNK activation, revealing a new regulator of γ-secretase-mediated APP processing under hypoxic conditions. We propose the role of phosphatase dual-specificity phosphatase 26 (DUSP26) in the selective regulation of Aβ42 production in neuronal cells under hypoxic stress. Induction of DUSP26 causes JNK-dependent shift in the subcellular localization of γ-secretase and C99 from the cell body to axons for Aβ42 generation. These findings provide a new strategy for developing new therapeutic targets to arrest AD progression.
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Affiliation(s)
- Sunmin Jung
- Global Research Laboratory, School of Biological Science, Seoul National University, Gwanak-gu, Seoul, Korea
| | - Jihoon Nah
- Global Research Laboratory, School of Biological Science, Seoul National University, Gwanak-gu, Seoul, Korea
| | - Jonghee Han
- Global Research Laboratory, School of Biological Science, Seoul National University, Gwanak-gu, Seoul, Korea
| | - Seon-Guk Choi
- Global Research Laboratory, School of Biological Science, Seoul National University, Gwanak-gu, Seoul, Korea
| | - Hyunjoo Kim
- Global Research Laboratory, School of Biological Science, Seoul National University, Gwanak-gu, Seoul, Korea
| | - Jaesang Park
- Global Research Laboratory, School of Biological Science, Seoul National University, Gwanak-gu, Seoul, Korea
| | - Ha-Kyung Pyo
- Global Research Laboratory, School of Biological Science, Seoul National University, Gwanak-gu, Seoul, Korea
| | - Yong-Keun Jung
- Global Research Laboratory, School of Biological Science, Seoul National University, Gwanak-gu, Seoul, Korea
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62
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Ben-Gedalya T, Cohen E. From mutated genes to familial Alzheimer's disease. Cell Cycle 2016; 15:877-8. [PMID: 26939744 DOI: 10.1080/15384101.2016.1151727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
- Tziona Ben-Gedalya
- a Department of Biochemistry and Molecular Biology , the Institute for Medical Research Israel - Canada (IMRIC), the Hebrew University School of Medicine , Jerusalem , Israel.,b Department of Obstetrics and Gynecology , Hadassah University Hospital, Ein Kerem , Jerusalem , Israel
| | - Ehud Cohen
- a Department of Biochemistry and Molecular Biology , the Institute for Medical Research Israel - Canada (IMRIC), the Hebrew University School of Medicine , Jerusalem , Israel
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63
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Cho S, Dickey SW, Urban S. Crystal Structures and Inhibition Kinetics Reveal a Two-Stage Catalytic Mechanism with Drug Design Implications for Rhomboid Proteolysis. Mol Cell 2016; 61:329-340. [PMID: 26805573 DOI: 10.1016/j.molcel.2015.12.022] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 11/20/2015] [Accepted: 12/15/2015] [Indexed: 12/28/2022]
Abstract
Intramembrane proteases signal by releasing proteins from the membrane, but despite their importance, their enzymatic mechanisms remain obscure. We probed rhomboid proteases with reversible, mechanism-based inhibitors that allow precise kinetic analysis and faithfully mimic the transition state structurally. Unexpectedly, inhibition by peptide aldehydes is non-competitive, revealing that in the Michaelis complex, substrate does not contact the catalytic center. Structural analysis in a membrane revealed that all extracellular loops of rhomboid make stabilizing interactions with substrate, but mainly through backbone interactions, explaining rhomboid's broad sequence selectivity. At the catalytic site, the tetrahedral intermediate lies covalently attached to the catalytic serine alone, with the oxyanion stabilized by unusual tripartite interactions with the side chains of H150, N154, and the backbone of S201. We also visualized unexpected substrate-enzyme interactions at the non-essential P2/P3 residues. These "extra" interactions foster potent rhomboid inhibition in living cells, thereby opening avenues for rational design of selective rhomboid inhibitors.
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Affiliation(s)
- Sangwoo Cho
- Howard Hughes Medical Institute, Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Room 507 PCTB, 725 North Wolfe Street, Baltimore, Maryland, USA, 21205
| | - Seth W Dickey
- Howard Hughes Medical Institute, Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Room 507 PCTB, 725 North Wolfe Street, Baltimore, Maryland, USA, 21205
| | - Siniša Urban
- Howard Hughes Medical Institute, Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Room 507 PCTB, 725 North Wolfe Street, Baltimore, Maryland, USA, 21205
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64
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Sparling DP, Yu J, Kim K, Zhu C, Brachs S, Birkenfeld AL, Pajvani UB. Adipocyte-specific blockade of gamma-secretase, but not inhibition of Notch activity, reduces adipose insulin sensitivity. Mol Metab 2015; 5:113-121. [PMID: 26909319 PMCID: PMC4735659 DOI: 10.1016/j.molmet.2015.11.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 11/18/2015] [Accepted: 11/25/2015] [Indexed: 01/12/2023] Open
Abstract
Objective As the obesity pandemic continues to expand, novel molecular targets to reduce obesity-related insulin resistance and Type 2 Diabetes (T2D) continue to be needed. We have recently shown that obesity is associated with reactivated liver Notch signaling, which, in turn, increases hepatic insulin resistance, opening up therapeutic avenues for Notch inhibitors to be repurposed for T2D. Herein, we tested the systemic effects of γ-secretase inhibitors (GSIs), which prevent endogenous Notch activation, and confirmed these effects through creation and characterization of two different adipocyte-specific Notch loss-of-function mouse models through genetic ablation of the Notch transcriptional effector Rbp-Jk (A-Rbpj) and the obligate γ-secretase component Nicastrin (A-Nicastrin). Methods Glucose homeostasis and both local adipose and systemic insulin sensitivity were examined in GSI-treated, A-Rbpj and A-Nicastrin mice, as well as vehicle-treated or control littermates, with complementary in vitro studies in primary hepatocytes and 3T3-L1 adipocytes. Results GSI-treatment increases hepatic insulin sensitivity in obese mice but leads to reciprocal lowering of adipose glucose disposal. While A-Rbpj mice show normal body weight, adipose development and mass and unchanged adipose insulin sensitivity as control littermates, A-Nicastrin mice are relatively insulin-resistant, mirroring the GSI effect on adipose insulin action. Conclusions Notch signaling is dispensable for normal adipocyte function, but adipocyte-specific γ-secretase blockade reduces adipose insulin sensitivity, suggesting that specific Notch inhibitors would be preferable to GSIs for application in T2D. γ-secretase inhibitors (GSIs) are non-specific inhibitors of Notch signaling. GSI-treatment of obese mice increases hepatic, but lowers adipose insulin sensitivity. Adipocyte-specific Notch inhibition does not affect adipose mass or glucose homeostasis. Adipocyte-specific γ-secretase blockade reduces adipose insulin sensitivity. Specific Notch inhibitors may be preferable to GSIs for treatment of Type 2 Diabetes.
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Affiliation(s)
- David P Sparling
- Departments of Pediatrics, Columbia University, New York, NY 10032, USA
| | - Junjie Yu
- Department of Medicine, Columbia University, New York, NY 10032, USA
| | - KyeongJin Kim
- Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Changyu Zhu
- Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Sebastian Brachs
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité - University School of Medicine, Berlin, Germany
| | - Andreas L Birkenfeld
- Section of Metabolic Vascular Medicine, Medical Clinic III and Paul Langerhans Institute Dresden (PLID), a member of the German Center for Diabetes Research (DZD), Technische Universität Dresden, Germany; Section of Diabetes and Nutritional Sciences, Rayne Institute, Denmark Hill Campus, King's College London, UK
| | - Utpal B Pajvani
- Department of Medicine, Columbia University, New York, NY 10032, USA.
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Peng F, Zhao Y, Huang X, Chen C, Sun L, Zhuang L, Xue L. Loss of Polo ameliorates APP-induced Alzheimer's disease-like symptoms in Drosophila. Sci Rep 2015; 5:16816. [PMID: 26597721 PMCID: PMC4657023 DOI: 10.1038/srep16816] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 10/15/2015] [Indexed: 12/13/2022] Open
Abstract
The amyloid precursor protein (APP) has been implicated in the pathogenesis of Alzheimer’s disease (AD). Despite extensive studies, little is known about the regulation of APP’s functions in vivo. Here we report that expression of human APP in Drosophila, in the same temporal-spatial pattern as its homolog APPL, induced morphological defects in wings and larval NMJ, larva and adult locomotion dysfunctions, male choice disorder and lifespan shortening. To identify additional genes that modulate APP functions, we performed a genetic screen and found that loss of Polo, a key regulator of cell cycle, partially suppressed APP-induced morphological and behavioral defects in larval and adult stages. Finally, we showed that eye-specific expression of APP induced retina degeneration and cell cycle re-entry, both phenotypes were mildly ameliorated by loss of Polo. These results suggest Polo is an important in vivo regulator of the pathological functions of APP, and provide insight into the role of cell cycle re-entry in AD pathogenesis.
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Affiliation(s)
- Fei Peng
- Institute of Intervention Vessel, Shanghai 10th People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Yu Zhao
- Institute of Intervention Vessel, Shanghai 10th People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Xirui Huang
- Institute of Intervention Vessel, Shanghai 10th People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Changyan Chen
- Institute of Intervention Vessel, Shanghai 10th People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Lili Sun
- School of Life Science and Technology, Tongji University, 1239 Siping Road, Shanghai 200092, P.R. China
| | - Luming Zhuang
- Institute of Intervention Vessel, Shanghai 10th People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Lei Xue
- Institute of Intervention Vessel, Shanghai 10th People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, 1239 Siping Road, Shanghai 200092, China
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Nguyen MTN, Kersavond TV, Verhelst SHL. Chemical Tools for the Study of Intramembrane Proteases. ACS Chem Biol 2015; 10:2423-34. [PMID: 26473325 DOI: 10.1021/acschembio.5b00693] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Intramembrane proteases (IMPs) reside inside lipid bilayers and perform peptide hydrolysis in transmembrane or juxtamembrane regions of their substrates. Many IMPs are involved in crucial regulatory pathways and human diseases, including Alzheimer's disease, Parkinson's disease, and diabetes. In the past, chemical tools have been instrumental in the study of soluble proteases, enabling biochemical and biomedical research in complex environments such as tissue lysates or living cells. However, IMPs place special challenges on probe design and applications, and progress has been much slower than for soluble proteases. In this review, we will give an overview of the available chemical tools for IMPs, including activity-based probes, affinity-based probes, and synthetic substrates. We will discuss how these have been used to increase our structural and functional understanding of this fascinating group of enzymes, and how they might be applied to address future questions and challenges.
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Affiliation(s)
- Minh T. N. Nguyen
- Leibniz Institute for Analytical Sciences ISAS, e.V., Otto-Hahn-Str. 6b, 44227 Dortmund, Germany
| | - Tim Van Kersavond
- Leibniz Institute for Analytical Sciences ISAS, e.V., Otto-Hahn-Str. 6b, 44227 Dortmund, Germany
| | - Steven H. L. Verhelst
- Leibniz Institute for Analytical Sciences ISAS, e.V., Otto-Hahn-Str. 6b, 44227 Dortmund, Germany
- KU Leuven − University of Leuven, Department
of Cellular and Molecular Medicine, Laboratory of Chemical Biology, Herestr. 49 Box 802, 3000 Leuven, Belgium
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67
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Maes H, Olmeda D, Soengas MS, Agostinis P. Vesicular trafficking mechanisms in endothelial cells as modulators of the tumor vasculature and targets of antiangiogenic therapies. FEBS J 2015; 283:25-38. [PMID: 26443003 DOI: 10.1111/febs.13545] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 09/21/2015] [Accepted: 10/02/2015] [Indexed: 11/25/2022]
Abstract
A common feature of solid tumors is their ability to incite the formation of new blood and lymph vessels trough the processes of angiogenesis and lymphangiogenesis, respectively, to support tumor growth and favor metastatic dissemination. As a result of the lack of feedback regulatory control mechanisms or due to the exacerbated presence of pro-angiogenic signals within the tumor microenvironment, the tumor endothelium receives continuous signals to sprout and develop, generating vessels that are structurally and functionally abnormal. An emerging mechanism playing a central role in shaping the tumor vasculature is the endothelial-vesicular network that regulates trafficking/export and degradation of key signaling proteins and membrane receptors, including the vascular endothelial growth-factor receptor-2/3 and members of the Notch pathway. Here we will discuss recent evidence highlighting how vesicular trafficking mechanisms in endothelial cells contribute to pathological angiogenesis/lymphangiogenesis and can provide novel and exploitable targets in antiangiogenic therapies.
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Affiliation(s)
- Hannelore Maes
- Cell Death Research & Therapy (CDRT) Unit, Department of Cellular and Molecular Medicine, KU Leuven University of Leuven, Belgium
| | - David Olmeda
- Melanoma Laboratory, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - María S Soengas
- Melanoma Laboratory, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Patrizia Agostinis
- Cell Death Research & Therapy (CDRT) Unit, Department of Cellular and Molecular Medicine, KU Leuven University of Leuven, Belgium
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68
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Walter J. Twenty Years of Presenilins--Important Proteins in Health and Disease. Mol Med 2015; 21 Suppl 1:S41-8. [PMID: 26605647 DOI: 10.2119/molmed.2015.00163] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 07/01/2015] [Indexed: 01/01/2023] Open
Abstract
Alzheimer's disease (AD) is characterized by progressive decline in cognitive functions associated with depositions of aggregated proteins in the form of extracellular plaques and neurofibrillary tangles in the brain. Extracellular plaques contain characteristic fibrils of amyloid β peptides (Aβ); tangles consist of paired helical filaments of the microtubuli-associated protein tau. Although AD manifests predominantly at ages above 65 years, rare cases show a much earlier onset of disease symptoms with very similar neuropathological characteristics. In 1995, two homologous genes were identified, in which mutations are associated with dominantly inherited familial forms of early onset AD. The genes therefore were dubbed presenilins (PS) and encode polytopic transmembrane proteins. At this time the role of these proteins in the pathogenesis of AD and their biological function in general were completely unknown. However, individuals carrying PS mutations showed alterations in the composition of different length variants of Aβ peptides in blood and cerebrospinal fluid, which indicated the potential involvement of presenilins in the metabolism of Aβ. After 20 years of intense research, the roles of presenilins in Aβ generation as well as important functions in biological processes have been identified. Presenilins represent the catalytic components of protease complexes that directly cleave the amyloid precursor protein (APP) but also many other proteins with important physiological functions. Here, the progress in presenilin research from basic characterization of their cellular functions to the targeting in clinical trials for AD therapy, and potential future directions, will be discussed.
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Affiliation(s)
- Jochen Walter
- Department of Neurology, University of Bonn, Bonn, Germany
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69
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Cavieres VA, González A, Muñoz VC, Yefi CP, Bustamante HA, Barraza RR, Tapia-Rojas C, Otth C, Barrera MJ, González C, Mardones GA, Inestrosa NC, Burgos PV. Tetrahydrohyperforin Inhibits the Proteolytic Processing of Amyloid Precursor Protein and Enhances Its Degradation by Atg5-Dependent Autophagy. PLoS One 2015; 10:e0136313. [PMID: 26308941 PMCID: PMC4550396 DOI: 10.1371/journal.pone.0136313] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 08/02/2015] [Indexed: 01/09/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the accumulation of amyloid-β (Aβ) peptide. We have previously shown that the compound tetrahydrohyperforin (IDN5706) prevents accumulation of Aβ species in an in vivo model of AD, however the mechanism that explains this reduction is not well understood. We show herein that IDN5706 decreases the levels of ER degradation enhancer, mannosidase alpha-like 1 (EDEM1), a key chaperone related to endoplasmic-reticulum-associated degradation (ERAD). Moreover, we observed that low levels of EDEM1 correlated with a strong activation of autophagy, suggesting a crosstalk between these two pathways. We observed that IDN5706 perturbs the glycosylation and proteolytic processing of the amyloid precursor protein (APP), resulting in the accumulation of immature APP (iAPP) in the endoplasmic reticulum. To investigate the contribution of autophagy, we tested the effect of IDN5706 in Atg5-depleted cells. We found that depletion of Atg5 enhanced the accumulation of iAPP in response to IDN5706 by slowing down its degradation. Our findings reveal that IDN5706 promotes degradation of iAPP via the activation of Atg5-dependent autophagy, shedding light on the mechanism that may contribute to the reduction of Aβ production in vivo.
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Affiliation(s)
- Viviana A. Cavieres
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
- Centro Interdisciplinario de Estudios del Sistema Nervioso (CISNe), Universidad Austral de Chile, Valdivia, Chile
| | - Alexis González
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
- Centro Interdisciplinario de Estudios del Sistema Nervioso (CISNe), Universidad Austral de Chile, Valdivia, Chile
| | - Vanessa C. Muñoz
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
- Centro Interdisciplinario de Estudios del Sistema Nervioso (CISNe), Universidad Austral de Chile, Valdivia, Chile
| | - Claudia P. Yefi
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
- Centro Interdisciplinario de Estudios del Sistema Nervioso (CISNe), Universidad Austral de Chile, Valdivia, Chile
| | - Hianara A. Bustamante
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
- Centro Interdisciplinario de Estudios del Sistema Nervioso (CISNe), Universidad Austral de Chile, Valdivia, Chile
| | - Rafael R. Barraza
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
- Centro Interdisciplinario de Estudios del Sistema Nervioso (CISNe), Universidad Austral de Chile, Valdivia, Chile
| | - Cheril Tapia-Rojas
- Centro de Envejecimiento y Regeneración (CARE), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carola Otth
- Instituto de Microbiología Clínica, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
| | - María José Barrera
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Carlos González
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
| | - Gonzalo A. Mardones
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
- Centro Interdisciplinario de Estudios del Sistema Nervioso (CISNe), Universidad Austral de Chile, Valdivia, Chile
| | - Nibaldo C. Inestrosa
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Center for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, Australia
- Centro UC Síndrome de Down, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
- * E-mail: (NCI); (PVB)
| | - Patricia V. Burgos
- Instituto de Fisiología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
- Centro Interdisciplinario de Estudios del Sistema Nervioso (CISNe), Universidad Austral de Chile, Valdivia, Chile
- * E-mail: (NCI); (PVB)
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Multhaup G, Huber O, Buée L, Galas MC. Amyloid Precursor Protein (APP) Metabolites APP Intracellular Fragment (AICD), Aβ42, and Tau in Nuclear Roles. J Biol Chem 2015; 290:23515-22. [PMID: 26296890 DOI: 10.1074/jbc.r115.677211] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Amyloid precursor protein (APP) metabolites (amyloid-β (Aβ) peptides) and Tau are the main components of senile plaques and neurofibrillary tangles, the two histopathological hallmarks of Alzheimer disease. Consequently, intense research has focused upon deciphering their physiological roles to understand their altered state in Alzheimer disease pathophysiology. Recently, the impact of APP metabolites (APP intracellular fragment (AICD) and Aβ) and Tau on the nucleus has emerged as an important, new topic. Here we discuss (i) how AICD, Aβ, and Tau reach the nucleus and how AICD and Aβ control protein expression at the transcriptional level, (ii) post-translational modifications of AICD, Aβ, and Tau, and (iii) what these three molecules have in common.
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Affiliation(s)
- Gerhard Multhaup
- From the Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada,
| | - Otmar Huber
- the Institute of Biochemistry II, Jena University Hospital, Friedrich Schiller University, D-07743 Jena, Germany, and
| | - Luc Buée
- the Jean Pierre Aubert Research Centre, Alzheimer & Tauopathies, INSERM, CHU-Lille, UMR-S 1172, University of Lille, F-59000 Lille, France
| | - Marie-Christine Galas
- the Jean Pierre Aubert Research Centre, Alzheimer & Tauopathies, INSERM, CHU-Lille, UMR-S 1172, University of Lille, F-59000 Lille, France
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71
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Lee JH, McBrayer MK, Wolfe DM, Haslett LJ, Kumar A, Sato Y, Lie PPY, Mohan P, Coffey EE, Kompella U, Mitchell CH, Lloyd-Evans E, Nixon RA. Presenilin 1 Maintains Lysosomal Ca(2+) Homeostasis via TRPML1 by Regulating vATPase-Mediated Lysosome Acidification. Cell Rep 2015; 12:1430-44. [PMID: 26299959 DOI: 10.1016/j.celrep.2015.07.050] [Citation(s) in RCA: 236] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 04/22/2015] [Accepted: 07/24/2015] [Indexed: 12/28/2022] Open
Abstract
Presenilin 1 (PS1) deletion or Alzheimer's disease (AD)-linked mutations disrupt lysosomal acidification and proteolysis, which inhibits autophagy. Here, we establish that this phenotype stems from impaired glycosylation and instability of vATPase V0a1 subunit, causing deficient lysosomal vATPase assembly and function. We further demonstrate that elevated lysosomal pH in Presenilin 1 knockout (PS1KO) cells induces abnormal Ca(2+) efflux from lysosomes mediated by TRPML1 and elevates cytosolic Ca(2+). In WT cells, blocking vATPase activity or knockdown of either PS1 or the V0a1 subunit of vATPase reproduces all of these abnormalities. Normalizing lysosomal pH in PS1KO cells using acidic nanoparticles restores normal lysosomal proteolysis, autophagy, and Ca(2+) homeostasis, but correcting lysosomal Ca(2+) deficits alone neither re-acidifies lysosomes nor reverses proteolytic and autophagic deficits. Our results indicate that vATPase deficiency in PS1 loss-of-function states causes lysosomal/autophagy deficits and contributes to abnormal cellular Ca(2+) homeostasis, thus linking two AD-related pathogenic processes through a common molecular mechanism.
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Affiliation(s)
- Ju-Hyun Lee
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University, New York, NY 10016, USA
| | - Mary Kate McBrayer
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Devin M Wolfe
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Luke J Haslett
- Division of Pathophysiology and Repair, Cardiff University, Cardiff CF10 3XQ, UK
| | - Asok Kumar
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Pathology, New York University, New York, NY 10016, USA
| | - Yutaka Sato
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Pearl P Y Lie
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA
| | - Panaiyur Mohan
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University, New York, NY 10016, USA
| | - Erin E Coffey
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Uday Kompella
- Pharmaceutical Science and Ophthalmology, University of Colorado, Aurora, CO 80045, USA
| | - Claire H Mitchell
- Department of Anatomy and Cell Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Emyr Lloyd-Evans
- Division of Pathophysiology and Repair, Cardiff University, Cardiff CF10 3XQ, UK
| | - Ralph A Nixon
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University, New York, NY 10016, USA; Department of Cell Biology, New York University, New York, NY 10016, USA.
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Kizuka Y, Kitazume S, Fujinawa R, Saito T, Iwata N, Saido TC, Nakano M, Yamaguchi Y, Hashimoto Y, Staufenbiel M, Hatsuta H, Murayama S, Manya H, Endo T, Taniguchi N. An aberrant sugar modification of BACE1 blocks its lysosomal targeting in Alzheimer's disease. EMBO Mol Med 2015; 7:175-89. [PMID: 25592972 PMCID: PMC4328647 DOI: 10.15252/emmm.201404438] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The β-site amyloid precursor protein cleaving enzyme-1 (BACE1), an essential protease for the generation of amyloid-β (Aβ) peptide, is a major drug target for Alzheimer's disease (AD). However, there is a concern that inhibiting BACE1 could also affect several physiological functions. Here, we show that BACE1 is modified with bisecting N-acetylglucosamine (GlcNAc), a sugar modification highly expressed in brain, and demonstrate that AD patients have higher levels of bisecting GlcNAc on BACE1. Analysis of knockout mice lacking the biosynthetic enzyme for bisecting GlcNAc, GnT-III (Mgat3), revealed that cleavage of Aβ-precursor protein (APP) by BACE1 is reduced in these mice, resulting in a decrease in Aβ plaques and improved cognitive function. The lack of this modification directs BACE1 to late endosomes/lysosomes where it is less colocalized with APP, leading to accelerated lysosomal degradation. Notably, other BACE1 substrates, CHL1 and contactin-2, are normally cleaved in GnT-III-deficient mice, suggesting that the effect of bisecting GlcNAc on BACE1 is selective to APP. Considering that GnT-III-deficient mice remain healthy, GnT-III may be a novel and promising drug target for AD therapeutics.
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Affiliation(s)
- Yasuhiko Kizuka
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center Global Research Cluster RIKEN, Wako, Japan
| | - Shinobu Kitazume
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center Global Research Cluster RIKEN, Wako, Japan
| | - Reiko Fujinawa
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center Global Research Cluster RIKEN, Wako, Japan
| | - Takashi Saito
- Laboratory for Proteolytic Neuroscience RIKEN Brain Science Institute, Wako, Japan
| | - Nobuhisa Iwata
- Laboratory for Proteolytic Neuroscience RIKEN Brain Science Institute, Wako, Japan Department of Genome-based Drug Discovery, Unit of Molecular Medicinal Sciences, Graduate School of Biomedical Sciences Nagasaki University, Nagasaki, Japan
| | - Takaomi C Saido
- Laboratory for Proteolytic Neuroscience RIKEN Brain Science Institute, Wako, Japan
| | - Miyako Nakano
- Graduate School of Advanced Sciences of Matter Hiroshima University, Higashihiroshima Hiroshima, Japan
| | - Yoshiki Yamaguchi
- Structural Glycobiology Team, RIKEN-Max Planck Joint Research Center Global Research Cluster RIKEN, Wako, Japan
| | - Yasuhiro Hashimoto
- Department of Biochemistry, Fukushima Medical University School of Medicine, Fukushima, Japan
| | | | - Hiroyuki Hatsuta
- Department of Neuropathology, Research Team for Mechanism of Aging, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Itabashi-ku Tokyo, Japan
| | - Shigeo Murayama
- Department of Neuropathology, Research Team for Mechanism of Aging, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Itabashi-ku Tokyo, Japan
| | - Hiroshi Manya
- Molecular Glycobiology, Research Team for Mechanism of Aging, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Itabashi-ku Tokyo, Japan
| | - Tamao Endo
- Molecular Glycobiology, Research Team for Mechanism of Aging, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Itabashi-ku Tokyo, Japan
| | - Naoyuki Taniguchi
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center Global Research Cluster RIKEN, Wako, Japan
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Wang X, Cui J, Li W, Zeng X, Zhao J, Pei G. γ-Secretase Modulators and Inhibitors Induce Different Conformational Changes of Presenilin 1 Revealed by FLIM and FRET. J Alzheimers Dis 2015; 47:927-37. [DOI: 10.3233/jad-150313] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Xin Wang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- Graduate School, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jin Cui
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- Graduate School, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Wei Li
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- Graduate School, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xianglu Zeng
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- Shanghai Key Laboratory of Signaling and Disease Research, Laboratory of Receptor-based Bio-medicine, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Jian Zhao
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Gang Pei
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- School of Life Science and Technology, and the Collaborative Innovation Center for Brain Science, Tongji University, Shanghai, China
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74
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Barage SH, Sonawane KD. Amyloid cascade hypothesis: Pathogenesis and therapeutic strategies in Alzheimer's disease. Neuropeptides 2015; 52:1-18. [PMID: 26149638 DOI: 10.1016/j.npep.2015.06.008] [Citation(s) in RCA: 356] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 06/24/2015] [Accepted: 06/24/2015] [Indexed: 01/08/2023]
Abstract
Alzheimer's disease is an irreversible, progressive neurodegenerative disorder. Various therapeutic approaches are being used to improve the cholinergic neurotransmission, but their role in AD pathogenesis is still unknown. Although, an increase in tau protein concentration in CSF has been described in AD, but several issues remains unclear. Extensive and accurate analysis of CSF could be helpful to define presence of tau proteins in physiological conditions, or released during the progression of neurodegenerative disease. The amyloid cascade hypothesis postulates that the neurodegeneration in AD caused by abnormal accumulation of amyloid beta (Aβ) plaques in various areas of the brain. The amyloid hypothesis has continued to gain support over the last two decades, particularly from genetic studies. Therefore, current research progress in several areas of therapies shall provide an effective treatment to cure this devastating disease. This review critically evaluates general biochemical and physiological functions of Aβ directed therapeutics and their relevance.
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Affiliation(s)
- Sagar H Barage
- Department of Biotechnology, Shivaji University, Kolhapur 416004, Maharashtra (M.S.), India
| | - Kailas D Sonawane
- Structural Bioinformatics Unit, Department of Biochemistry, Shivaji University, Kolhapur 416004, Maharashtra (M.S.), India; Department of Microbiology, Shivaji University, Kolhapur 416004, Maharashtra (M.S.), India.
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75
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Zeng L, Hu C, Zhang F, Xu DC, Cui MZ, Xu X. Cellular FLICE-like Inhibitory Protein (c-FLIP) and PS1-associated Protein (PSAP) Mediate Presenilin 1-induced γ-Secretase-dependent and -independent Apoptosis, Respectively. J Biol Chem 2015; 290:18269-80. [PMID: 26025363 DOI: 10.1074/jbc.m115.640177] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Indexed: 12/21/2022] Open
Abstract
Presenilin 1 (PS1) has been implicated in apoptosis; however, its mechanism remains elusive. We report that PS1-induced apoptosis was associated with cellular FLICE-like inhibitory protein (c-FLIP) turnover and that γ-secretase inhibitor blocked c-FLIP turnover and also partially blocked PS1-induced apoptosis. A complete inhibition of PS1-induced apoptosis was achieved by knockdown of PS1-associated protein (PSAP), a mitochondrial proapoptotic protein that forms a complex with Bax upon induction of apoptosis, in the presence of γ-secretase inhibitor. PS1-induced apoptosis was partially inhibited by knockdown of caspase-8, Fas-associated protein with death domain (FADD), or Bid. However, knockdown of Bax or overexpression of Bcl-2 resulted in complete inhibition of PS1-induced apoptosis. These data suggest that PS1 induces apoptosis through two pathways: the γ-secretase-dependent pathway mediated by turnover of c-FLIP and the γ-secretase-independent pathway mediated by PSAP-Bax complex formation. These two pathways converge on Bax to activate mitochondria-dependent apoptosis. These findings provide new insight into the mechanisms by which PS1 is involved in apoptosis and the mechanism by which PS1 exerts its pathogenic effects. In addition, our results suggest that PS2 induces apoptosis through a pathway that is different from that of PS1.
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Affiliation(s)
- Linlin Zeng
- From the Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, and
| | - Chen Hu
- From the Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, and the Department of Comparative and Experimental Medicine, University of Tennessee, Knoxville, Tennessee 37996 and
| | - Fuqiang Zhang
- From the Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, and
| | - Daniel C Xu
- the Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544
| | - Mei-Zhen Cui
- From the Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, and
| | - Xuemin Xu
- From the Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, and
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76
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Kizuka Y, Kitazume S, Sato K, Taniguchi N. Clec4g (LSECtin) interacts with BACE1 and suppresses Aβ generation. FEBS Lett 2015; 589:1418-22. [PMID: 25957769 DOI: 10.1016/j.febslet.2015.04.060] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 04/16/2015] [Accepted: 04/30/2015] [Indexed: 12/21/2022]
Abstract
β-Site amyloid precursor protein cleaving enzyme-1 (BACE1) is a central molecule in Alzheimer's disease (AD). It cleaves amyloid precursor protein (APP) to produce the toxic amyloid-β (Aβ) peptides. Thus, a novel BACE1 modulator could offer a new therapeutic strategy for AD. We report that C-type lectin-like domain family 4, member g (Clec4g, also designated as LSECtin) interacts with BACE1 in mouse brain and cultured cells. Overexpression of Clec4g suppressed BACE1-mediated Aβ generation, and affected the intracellular distribution of BACE1 but not its catalytic activity. These results highlight a novel role of Clec4g in negatively regulating BACE1 function.
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Affiliation(s)
- Yasuhiko Kizuka
- Disease Glycomics Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center for Systems Chemical Biology, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Shinobu Kitazume
- Disease Glycomics Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center for Systems Chemical Biology, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Keiko Sato
- Disease Glycomics Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center for Systems Chemical Biology, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Naoyuki Taniguchi
- Disease Glycomics Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center for Systems Chemical Biology, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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77
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Pain C, Dumont J, Dumoulin M. Camelid single-domain antibody fragments: Uses and prospects to investigate protein misfolding and aggregation, and to treat diseases associated with these phenomena. Biochimie 2015; 111:82-106. [DOI: 10.1016/j.biochi.2015.01.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 01/23/2015] [Indexed: 12/19/2022]
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78
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Early etiology of Alzheimer's disease: tipping the balance toward autophagy or endosomal dysfunction? Acta Neuropathol 2015; 129:363-81. [PMID: 25556159 PMCID: PMC4331606 DOI: 10.1007/s00401-014-1379-7] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 12/18/2014] [Accepted: 12/20/2014] [Indexed: 12/11/2022]
Abstract
Alzheimer’s disease (AD) is the most common form of dementia in the elderly. This brain neuropathology is characterized by a progressive synaptic dysfunction and neuronal loss, which lead to decline in memory and other cognitive functions. Histopathologically, AD manifests via synaptic abnormalities, neuronal degeneration as well as the deposition of extracellular amyloid plaques and intraneuronal neurofibrillary tangles. While the exact pathogenic contribution of these two AD hallmarks and their abundant constituents [aggregation-prone amyloid β (Aβ) peptide species and hyperphosphorylated tau protein, respectively] remain debated, a growing body of evidence suggests that their development may be paralleled or even preceded by the alterations/dysfunctions in the endolysosomal and the autophagic system. In AD-affected neurons, abnormalities in these cellular pathways are readily observed already at early stages of disease development, and even though many studies agree that defective lysosomal degradation may relate to or even underlie some of these deficits, specific upstream molecular defects are still deliberated. In this review we summarize various pathogenic events that may lead to these cellular abnormalities, in light of our current understanding of molecular mechanisms that govern AD progression. In addition, we also highlight the increasing evidence supporting mutual functional dependence of the endolysosomal trafficking and autophagy, in particular focusing on those molecules and processes which may be of significance to AD.
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79
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Li Y, Bohm C, Dodd R, Chen F, Qamar S, Schmitt-Ulms G, Fraser PE, St George-Hyslop PH. Structural biology of presenilin 1 complexes. Mol Neurodegener 2014; 9:59. [PMID: 25523933 PMCID: PMC4326451 DOI: 10.1186/1750-1326-9-59] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 12/12/2014] [Indexed: 11/17/2022] Open
Abstract
The presenilin genes were first identified as the site of missense mutations causing early onset autosomal dominant familial Alzheimer's disease. Subsequent work has shown that the presenilin proteins are the catalytic subunits of a hetero-tetrameric complex containing APH1, nicastrin and PEN-2. This complex (variously termed presenilin complex or gamma-secretase complex) performs an unusual type of proteolysis in which the transmembrane domains of Type I proteins are cleaved within the hydrophobic compartment of the membrane. This review describes some of the molecular and structural biology of this unusual enzyme complex. The presenilin complex is a bilobed structure. The head domain contains the ectodomain of nicastrin. The base domain contains a central cavity with a lateral cleft that likely provides the route for access of the substrate to the catalytic cavity within the centre of the base domain. There are reciprocal allosteric interactions between various sites in the complex that affect its function. For instance, binding of Compound E, a peptidomimetic inhibitor to the PS1 N-terminus, induces significant conformational changes that reduces substrate binding at the initial substrate docking site, and thus inhibits substrate cleavage. However, there is a reciprocal allosteric interaction between these sites such that prior binding of the substrate to the initial docking site paradoxically increases the binding of the Compound E peptidomimetic inhibitor. Such reciprocal interactions are likely to form the basis of a gating mechanism that underlies access of substrate to the catalytic site. An increasingly detailed understanding of the structural biology of the presenilin complex is an essential step towards rational design of substrate- and/or cleavage site-specific modulators of presenilin complex function.
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Affiliation(s)
| | | | | | | | | | | | | | - Peter H St George-Hyslop
- Cambridge Institute for Medical Research, Wellcome Trust MRC Building, Addenbrookes Hospital, Hills Road, Cambridge CB2 0XY, UK.
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80
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Morishima-Kawashima M. Molecular mechanism of the intramembrane cleavage of the β-carboxyl terminal fragment of amyloid precursor protein by γ-secretase. Front Physiol 2014; 5:463. [PMID: 25505888 PMCID: PMC4245903 DOI: 10.3389/fphys.2014.00463] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Accepted: 11/11/2014] [Indexed: 01/31/2023] Open
Abstract
Amyloid β-protein (Aβ) plays a central role in the pathogenesis of Alzheimer's disease, the most common age-associated neurodegenerative disorder. Aβ is generated through intramembrane proteolysis of the β-carboxyl terminal fragment (βCTF) of β-amyloid precursor protein (APP) by γ-secretase. The initial cleavage by γ-secretase occurs in the membrane/cytoplasm boundary of the βCTF, liberating the APP intracellular domain (AICD). The remaining βCTFs, which are truncated at the C-terminus (longer Aβs), are then cropped sequentially in a stepwise manner, predominantly at three residue intervals, to generate Aβ. There are two major Aβ product lines which generate Aβ40 and Aβ42 with concomitant release of three and two tripeptides, respectively. Additionally, many alternative cleavages occur, releasing peptides with three to six residues. These modulate the Aβ product lines and define the species and quantity of Aβ generated. Here, we review our current understanding of the intramembrane cleavage of the βCTF by γ-secretase, which may contribute to the future goal of developing an efficient therapeutic strategy for Alzheimer's disease.
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Affiliation(s)
- Maho Morishima-Kawashima
- Laboratory of Neuroscience, Graduate School of Pharmaceutical Sciences, Hokkaido University Sapporo, Japan
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81
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Strömberg K, Eketjäll S, Georgievska B, Tunblad K, Eliason K, Olsson F, Radesäter AC, Klintenberg R, Arvidsson PI, von Berg S, Fälting J, Cowburn RF, Dabrowski M. Combining an amyloid-beta (Aβ) cleaving enzyme inhibitor with a γ-secretase modulator results in an additive reduction of Aβ production. FEBS J 2014; 282:65-73. [DOI: 10.1111/febs.13103] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/31/2014] [Accepted: 10/06/2014] [Indexed: 12/27/2022]
Affiliation(s)
- Kia Strömberg
- Department of Neuroscience; AstraZeneca R&D; CNS/Pain iMED; Södertälje Sweden
| | - Susanna Eketjäll
- AstraZeneca Translational Science Centre; Science for Life Laboratory; Solna Sweden
| | - Biljana Georgievska
- Department of Neuroscience; AstraZeneca R&D; CNS/Pain iMED; Södertälje Sweden
| | - Karin Tunblad
- Department of Neuroscience; AstraZeneca R&D; CNS/Pain iMED; Södertälje Sweden
| | - Kristina Eliason
- Department of Neuroscience; AstraZeneca R&D; CNS/Pain iMED; Södertälje Sweden
| | - Fredrik Olsson
- Department of Neuroscience; AstraZeneca R&D; CNS/Pain iMED; Södertälje Sweden
| | | | - Rebecka Klintenberg
- Department of Neuroscience; AstraZeneca R&D; CNS/Pain iMED; Södertälje Sweden
| | - Per I. Arvidsson
- Project Management, AstraZeneca R&D; CNS/Pain iMED; Södertälje Sweden
| | - Stefan von Berg
- Department of Medicinal Chemistry; R&I iMed; AstraZeneca R&D Mölndal; Sweden
| | - Johanna Fälting
- Project Management, AstraZeneca R&D; CNS/Pain iMED; Södertälje Sweden
| | - Richard F. Cowburn
- Department of Neuroscience; AstraZeneca R&D; CNS/Pain iMED; Södertälje Sweden
| | - Michael Dabrowski
- Department of Neuroscience; AstraZeneca R&D; CNS/Pain iMED; Södertälje Sweden
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82
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Haapasalo A, Viswanathan J, Kurkinen KM, Bertram L, Soininen H, Dantuma NP, Tanzi RE, Hiltunen M. Involvement of ubiquilin-1 transcript variants in protein degradation and accumulation. Commun Integr Biol 2014. [DOI: 10.4161/cib.15283] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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83
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Wang X, Huang T, Zhao Y, Zheng Q, Thompson RC, Bu G, Zhang YW, Hong W, Xu H. Sorting nexin 27 regulates Aβ production through modulating γ-secretase activity. Cell Rep 2014; 9:1023-33. [PMID: 25437557 DOI: 10.1016/j.celrep.2014.09.037] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Revised: 08/04/2014] [Accepted: 09/18/2014] [Indexed: 12/14/2022] Open
Abstract
Patients with Down syndrome (DS) invariably develop Alzheimer's disease (AD) pathology in their 40s. We have recently found that overexpression of a chromosome 21-encoded microRNA-155 results in decreased levels of the membrane trafficking component, SNX27, diminishing glutamate receptor recycling and thereby impairing synaptic functions in DS. Here, we report a function of SNX27 in regulating β-amyloid (Aβ) generation by modulating γ-secretase activity. Downregulation of SNX27 using RNAi increased Aβ production, whereas overexpression of full-length SNX27, but not SNX27ΔPDZ, reversed the RNAi-mediated Aβ elevation. Moreover, genetic deletion of Snx27 promoted Aβ production and neuronal loss, whereas overexpression of SNX27 using an adeno-associated viral (AAV) vector reduced hippocampal Aβ levels in a transgenic AD mouse model. SNX27 associates with the γ-secretase complex subunit presenilin 1; this interaction dissociates the γ-secretase complex, thus decreasing its proteolytic activity. Our study establishes a molecular mechanism for Aβ-dependent pathogenesis in both DS and AD.
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Affiliation(s)
- Xin Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361005, China; Degenerative Disease Research Program, Center for Neuroscience, Aging, and Stem Cell Research, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Timothy Huang
- Degenerative Disease Research Program, Center for Neuroscience, Aging, and Stem Cell Research, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Yingjun Zhao
- Degenerative Disease Research Program, Center for Neuroscience, Aging, and Stem Cell Research, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Qiuyang Zheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361005, China; Degenerative Disease Research Program, Center for Neuroscience, Aging, and Stem Cell Research, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Robert C Thompson
- Degenerative Disease Research Program, Center for Neuroscience, Aging, and Stem Cell Research, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Guojun Bu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361005, China
| | - Yun-wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361005, China; Degenerative Disease Research Program, Center for Neuroscience, Aging, and Stem Cell Research, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Wanjin Hong
- Institute for Biomedical Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen 361005, China; Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore 138673, Singapore
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, Medical College, Xiamen University, Xiamen 361005, China; Degenerative Disease Research Program, Center for Neuroscience, Aging, and Stem Cell Research, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA.
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84
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Askanas V, Engel WK, Nogalska A. Sporadic inclusion-body myositis: A degenerative muscle disease associated with aging, impaired muscle protein homeostasis and abnormal mitophagy. Biochim Biophys Acta Mol Basis Dis 2014; 1852:633-43. [PMID: 25241263 DOI: 10.1016/j.bbadis.2014.09.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 09/09/2014] [Accepted: 09/10/2014] [Indexed: 01/13/2023]
Abstract
Sporadic inclusion-body myositis (s-IBM) is the most common degenerative muscle disease in which aging appears to be a key risk factor. In this review we focus on several cellular molecular mechanisms responsible for multiprotein aggregation and accumulations within s-IBM muscle fibers, and their possible consequences. Those include mechanisms leading to: a) accumulation in the form of aggregates within the muscle fibers, of several proteins, including amyloid-β42 and its oligomers, and phosphorylated tau in the form of paired helical filaments, and we consider their putative detrimental influence; and b) protein misfolding and aggregation, including evidence of abnormal myoproteostasis, such as increased protein transcription, inadequate protein disposal, and abnormal posttranslational modifications of proteins. Pathogenic importance of our recently demonstrated abnormal mitophagy is also discussed. The intriguing phenotypic similarities between s-IBM muscle fibers and the brains of Alzheimer and Parkinson's disease patients, the two most common neurodegenerative diseases associated with aging, are also discussed. This article is part of a Special Issue entitled: Neuromuscular Diseases: Pathology and Molecular Pathogenesis.
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Affiliation(s)
- Valerie Askanas
- USC Neuromuscular Center, Department of Neurology, University of Southern California Keck School of Medicine, Good Samaritan Hospital, Los Angeles, CA, USA.
| | - W King Engel
- USC Neuromuscular Center, Department of Neurology, University of Southern California Keck School of Medicine, Good Samaritan Hospital, Los Angeles, CA, USA
| | - Anna Nogalska
- USC Neuromuscular Center, Department of Neurology, University of Southern California Keck School of Medicine, Good Samaritan Hospital, Los Angeles, CA, USA
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85
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Urban S, Moin SM. A subset of membrane-altering agents and γ-secretase modulators provoke nonsubstrate cleavage by rhomboid proteases. Cell Rep 2014; 8:1241-7. [PMID: 25159145 DOI: 10.1016/j.celrep.2014.07.039] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 05/05/2014] [Accepted: 07/22/2014] [Indexed: 01/04/2023] Open
Abstract
Rhomboid proteases are integral membrane enzymes that regulate cell signaling, adhesion, and organelle homeostasis pathways, making substrate specificity a key feature of their function. Interestingly, we found that perturbing the membrane pharmacologically in living cells had little effect on substrate processing but induced inappropriate cleavage of nonsubstrates by rhomboid proteases. A subclass of drugs known to modulate γ-secretase activity acted on the membrane directly and induced nonsubstrate cleavage by rhomboid proteases but left true substrate cleavage sites unaltered. These observations highlight an active role for the membrane in guiding rhomboid selectivity and caution that membrane-targeted drugs should be evaluated for cross-activity against membrane-resident enzymes that are otherwise unrelated to the intended drug target. Furthermore, some γ-secretase-modulating activity or toxicity could partly result from global membrane effects.
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Affiliation(s)
- Siniša Urban
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Syed M Moin
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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86
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Maes H, Kuchnio A, Peric A, Moens S, Nys K, De Bock K, Quaegebeur A, Schoors S, Georgiadou M, Wouters J, Vinckier S, Vankelecom H, Garmyn M, Vion AC, Radtke F, Boulanger C, Gerhardt H, Dejana E, Dewerchin M, Ghesquière B, Annaert W, Agostinis P, Carmeliet P. Tumor vessel normalization by chloroquine independent of autophagy. Cancer Cell 2014; 26:190-206. [PMID: 25117709 DOI: 10.1016/j.ccr.2014.06.025] [Citation(s) in RCA: 306] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 01/06/2014] [Accepted: 06/27/2014] [Indexed: 12/21/2022]
Abstract
Chloroquine (CQ) has been evaluated as an autophagy blocker for cancer treatment, but it is unknown if it acts solely by inhibiting cancer cell autophagy. We report that CQ reduced tumor growth but improved the tumor milieu. By normalizing tumor vessel structure and function and increasing perfusion, CQ reduced hypoxia, cancer cell invasion, and metastasis, while improving chemotherapy delivery and response. Inhibiting autophagy in cancer cells or endothelial cells (ECs) failed to induce such effects. CQ's vessel normalization activity relied mainly on alterations of endosomal Notch1 trafficking and signaling in ECs and was abrogated by Notch1 deletion in ECs in vivo. Thus, autophagy-independent vessel normalization by CQ restrains tumor invasion and metastasis while improving chemotherapy, supporting the use of CQ for anticancer treatment.
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MESH Headings
- Angiogenesis Inhibitors/pharmacology
- Angiogenesis Inhibitors/therapeutic use
- Animals
- Autophagy
- Autophagy-Related Protein 5
- Camptothecin/pharmacology
- Cell Line, Tumor
- Cell Proliferation/drug effects
- Chloroquine/pharmacology
- Chloroquine/therapeutic use
- Drug Synergism
- Endothelial Cells/drug effects
- Endothelial Cells/physiology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/pathology
- Humans
- Melanoma, Experimental/blood supply
- Melanoma, Experimental/drug therapy
- Melanoma, Experimental/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Nude
- Microtubule-Associated Proteins/metabolism
- Neoplasm Invasiveness
- Neovascularization, Pathologic/metabolism
- Neovascularization, Pathologic/prevention & control
- Receptor, Notch1/metabolism
- Skin Neoplasms/blood supply
- Skin Neoplasms/drug therapy
- Skin Neoplasms/pathology
- Tumor Burden/drug effects
- Xenograft Model Antitumor Assays
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Affiliation(s)
- Hannelore Maes
- Department Cellular and Molecular Medicine, Laboratory of Cell Death and Therapy, KU Leuven, B-3000 Leuven, Belgium
| | - Anna Kuchnio
- Department of Oncology, Laboratory of Angiogenesis and Neurovascular Link, KU Leuven, B-3000 Leuven, Belgium; Vesalius Research Center, Laboratory of Angiogenesis and Neurovascular Link, VIB, B-3000 Leuven, Belgium
| | - Aleksandar Peric
- Department of Human Genetics and VIB-Center for the Biology of Disease, Laboratory for Membrane Trafficking, B-3000 Leuven, Leuven 3000, Belgium
| | - Stijn Moens
- Department of Oncology, Laboratory of Angiogenesis and Neurovascular Link, KU Leuven, B-3000 Leuven, Belgium; Vesalius Research Center, Laboratory of Angiogenesis and Neurovascular Link, VIB, B-3000 Leuven, Belgium
| | - Kris Nys
- Department Cellular and Molecular Medicine, Laboratory of Cell Death and Therapy, KU Leuven, B-3000 Leuven, Belgium
| | - Katrien De Bock
- Department of Oncology, Laboratory of Angiogenesis and Neurovascular Link, KU Leuven, B-3000 Leuven, Belgium; Vesalius Research Center, Laboratory of Angiogenesis and Neurovascular Link, VIB, B-3000 Leuven, Belgium
| | - Annelies Quaegebeur
- Department of Oncology, Laboratory of Angiogenesis and Neurovascular Link, KU Leuven, B-3000 Leuven, Belgium; Vesalius Research Center, Laboratory of Angiogenesis and Neurovascular Link, VIB, B-3000 Leuven, Belgium
| | - Sandra Schoors
- Department of Oncology, Laboratory of Angiogenesis and Neurovascular Link, KU Leuven, B-3000 Leuven, Belgium; Vesalius Research Center, Laboratory of Angiogenesis and Neurovascular Link, VIB, B-3000 Leuven, Belgium
| | - Maria Georgiadou
- Department of Oncology, Laboratory of Angiogenesis and Neurovascular Link, KU Leuven, B-3000 Leuven, Belgium; Vesalius Research Center, Laboratory of Angiogenesis and Neurovascular Link, VIB, B-3000 Leuven, Belgium
| | - Jasper Wouters
- Department of Imaging & Pathology, Translational Cell and Tissue Research, KU Leuven, B-3000 Leuven, Belgium; Department of Development and Regeneration, Embryo and Stem Cells Unit, KU Leuven, B-3000 Leuven, Belgium
| | - Stefan Vinckier
- Department of Oncology, Laboratory of Angiogenesis and Neurovascular Link, KU Leuven, B-3000 Leuven, Belgium; Vesalius Research Center, Laboratory of Angiogenesis and Neurovascular Link, VIB, B-3000 Leuven, Belgium
| | - Hugo Vankelecom
- Department of Development and Regeneration, Embryo and Stem Cells Unit, KU Leuven, B-3000 Leuven, Belgium
| | - Marjan Garmyn
- Department of Oncology, Laboratory Dermatology, KU Leuven, B-3000 Leuven, Belgium
| | | | - Freddy Radtke
- Ecole Polytechnique Fédérale de Lausanne, School of Life Science, 1015 Lausanne, Switzerland; Swiss Institute for Experimental Cancer Research, 1015 Lausanne, Switzerland
| | - Chantal Boulanger
- Cardiovascular Research Center, INSERM UMR-970, Paris Cedex 15, France
| | - Holger Gerhardt
- Vascular Biology Laboratory, London Research Institute, Cancer Research UK, London WC2A 3LY, UK; Department of Oncology, Vascular Patterning Laboratory, KU Leuven, B-3000 Leuven, Belgium; Vesalius Research Center, Vascular Patterning Laboratory, VIB, B-3000 Leuven, Belgium
| | - Elisabetta Dejana
- Vascular Biology Program, IFOM, FIRC Institute of Molecular Oncology Foundation, 20139 Milan, Italy
| | - Mieke Dewerchin
- Department of Oncology, Laboratory of Angiogenesis and Neurovascular Link, KU Leuven, B-3000 Leuven, Belgium; Vesalius Research Center, Laboratory of Angiogenesis and Neurovascular Link, VIB, B-3000 Leuven, Belgium
| | - Bart Ghesquière
- Department of Oncology, Laboratory of Angiogenesis and Neurovascular Link, KU Leuven, B-3000 Leuven, Belgium; Vesalius Research Center, Laboratory of Angiogenesis and Neurovascular Link, VIB, B-3000 Leuven, Belgium
| | - Wim Annaert
- Department of Human Genetics and VIB-Center for the Biology of Disease, Laboratory for Membrane Trafficking, B-3000 Leuven, Leuven 3000, Belgium
| | - Patrizia Agostinis
- Department Cellular and Molecular Medicine, Laboratory of Cell Death and Therapy, KU Leuven, B-3000 Leuven, Belgium.
| | - Peter Carmeliet
- Department of Oncology, Laboratory of Angiogenesis and Neurovascular Link, KU Leuven, B-3000 Leuven, Belgium; Vesalius Research Center, Laboratory of Angiogenesis and Neurovascular Link, VIB, B-3000 Leuven, Belgium
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87
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The FAM3 superfamily member ILEI ameliorates Alzheimer's disease-like pathology by destabilizing the penultimate amyloid-β precursor. Nat Commun 2014; 5:3917. [PMID: 24894631 DOI: 10.1038/ncomms4917] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 04/16/2014] [Indexed: 01/12/2023] Open
Abstract
Accumulation of amyloid-β peptide (Aβ) in the brain underlies the pathogenesis of Alzheimer's disease (AD). Aβ is produced by β- and γ-secretase-mediated sequential proteolysis of amyloid-β precursor protein (APP). Here we identify a secretory protein named interleukin-like epithelial-mesenchymal transition inducer (ILEI, also known as FAM3 superfamily member C) as a negative regulator of Aβ production. ILEI destabilizes the β-secretase-cleaved APP carboxy-terminal fragment, the penultimate precursor of Aβ, by binding to the γ-secretase complex and interfering with its chaperone properties. Notch signalling and γ-secretase activity are not affected by ILEI. We also show neuronal expression of ILEI and its induction by transforming growth factor-β signalling. The level of secreted ILEI is markedly decreased in the brains of AD patients. Transgenic (Tg) overexpression of ILEI significantly reduces the brain Aβ burden and ameliorates the memory deficit in AD model mice. ILEI may be a plausible target for the development of disease-modifying therapies.
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88
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Barucker C, Harmeier A, Weiske J, Fauler B, Albring KF, Prokop S, Hildebrand P, Lurz R, Heppner FL, Huber O, Multhaup G. Nuclear translocation uncovers the amyloid peptide Aβ42 as a regulator of gene transcription. J Biol Chem 2014; 289:20182-91. [PMID: 24878959 DOI: 10.1074/jbc.m114.564690] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Although soluble species of the amyloid-β peptide Aβ42 correlate with disease symptoms in Alzheimer disease, little is known about the biological activities of amyloid-β (Aβ). Here, we show that Aβ peptides varying in lengths from 38 to 43 amino acids are internalized by cultured neuroblastoma cells and can be found in the nucleus. By three independent methods, we demonstrate direct detection of nuclear Aβ42 as follows: (i) biochemical analysis of nuclear fractions; (ii) detection of biotin-labeled Aβ in living cells by confocal laser scanning microscopy; and (iii) transmission electron microscopy of Aβ in cultured cells, as well as brain tissue of wild-type and transgenic APPPS1 mice (overexpression of amyloid precursor protein and presenilin 1 with Swedish and L166P mutations, respectively). Also, this study details a novel role for Aβ42 in nuclear signaling, distinct from the amyloid precursor protein intracellular domain. Chromatin immunoprecipitation showed that Aβ42 specifically interacts as a repressor of gene transcription with LRP1 and KAI1 promoters. By quantitative RT-PCR, we confirmed that mRNA levels of the examined candidate genes were exclusively decreased by the potentially neurotoxic Aβ42 wild-type peptide. Shorter peptides (Aβ38 or Aβ40) and other longer peptides (nontoxic Aβ42 G33A substitution or Aβ43) did not affect mRNA levels. Overall, our data indicate that the nuclear translocation of Aβ42 impacts gene regulation, and deleterious effects of Aβ42 in Alzheimer disease pathogenesis may be influenced by altering the expression profiles of disease-modifying genes.
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Affiliation(s)
- Christian Barucker
- From the Institut fuer Chemie und Biochemie, Freie Universitaet Berlin, 14195 Berlin, Germany, the Department of Pharmacology and Therapeutics, Faculty of Medicine, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Anja Harmeier
- From the Institut fuer Chemie und Biochemie, Freie Universitaet Berlin, 14195 Berlin, Germany
| | - Joerg Weiske
- the Institute of Clinical Chemistry and Pathobiochemistry, Charite-Campus Benjamin Franklin, 12203 Berlin, Germany
| | - Beatrix Fauler
- the Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Kai Frederik Albring
- the Institute of Clinical Chemistry and Pathobiochemistry, Charite-Campus Benjamin Franklin, 12203 Berlin, Germany, the Institute of Biochemistry II, Jena University Hospital, Friedrich Schiller University, 07743 Jena, Germany, and
| | | | - Peter Hildebrand
- Institute of Medical Physics and Biophysics, Charite-Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Rudi Lurz
- the Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | | | - Otmar Huber
- the Institute of Clinical Chemistry and Pathobiochemistry, Charite-Campus Benjamin Franklin, 12203 Berlin, Germany, the Institute of Biochemistry II, Jena University Hospital, Friedrich Schiller University, 07743 Jena, Germany, and
| | - Gerhard Multhaup
- From the Institut fuer Chemie und Biochemie, Freie Universitaet Berlin, 14195 Berlin, Germany, the Department of Pharmacology and Therapeutics, Faculty of Medicine, McGill University, Montreal, Quebec H3G 0B1, Canada,
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89
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Loss of presenilin 2 is associated with increased iPLA2 activity and lung tumor development. Oncogene 2014; 33:5193-200. [PMID: 24858037 PMCID: PMC4287650 DOI: 10.1038/onc.2014.128] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 04/11/2014] [Accepted: 04/14/2014] [Indexed: 12/17/2022]
Abstract
Presenilins are the enzymatic components of γ-secretase complex that cleaves amyloid precursor protein, Notch and β-catenin, which has critical roles in the development of Alzheimer's disease and cancer cell growth. Therefore, in the present study, we studied the effects and mechanisms of PS2 knockout on lung cancer development and possible mechanisms as a key regulator of lung tumor development. We compared carcinogen-induced tumor growth between PS2 knockout mice and wild-type mice. PS2 knockout mice showed increased urethane (1 mg/g)-induced lung tumor incidence when compared with that of wild-type mice with decreased activity of γ-secretase in the lung tumor tissues. Consequently, iPLA2 activities in lung tumor tissues of PS2 knockout mice were much higher than in tumor tissues of wild-type mice. Furthermore, knockdown of PS2 using PS2 siRNA decreased γ-secretase activity with increased iPLA2 activity in the lung cancer cells (A549 and NCI-H460), leading to increased lung cancer cell growth. PS2 knockout mice and PS2 knockdown lung cancer cells showed increased DNA-binding activities of nuclear factor kappa-beta, signal transducer and activator of transcription 3 (STAT3) and AP-1 which are critical transcriptional factors of iPLA2 than those of PS2 wild-type mice and control lung cancer cells. Taken together, these results suggest that the loss of PS2 could have a critical role in lung tumor development through the upregulation of iPLA2 activity by reducing γ-secretase.
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90
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Ludtmann MHR, Otto GP, Schilde C, Chen ZH, Allan CY, Brace S, Beesley PW, Kimmel AR, Fisher P, Killick R, Williams RSB. An ancestral non-proteolytic role for presenilin proteins in multicellular development of the social amoeba Dictyostelium discoideum. J Cell Sci 2014; 127:1576-84. [PMID: 24463814 PMCID: PMC3970561 DOI: 10.1242/jcs.140939] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 12/29/2013] [Indexed: 11/20/2022] Open
Abstract
Mutations in either of two presenilin genes can cause familial Alzheimer's disease. Presenilins have both proteolysis-dependent functions, as components of the γ-secretase complex, and proteolysis-independent functions in signalling. In this study, we investigate a conserved function of human presenilins in the development of the simple model organism Dictyostelium discoideum. We show that the block in Dictyostelium development caused by the ablation of both Dictyostelium presenilins is rescued by the expression of human presenilin 1, restoring the terminal differentiation of multiple cell types. This developmental role is independent of proteolytic activity, because the mutation of both catalytic aspartates does not affect presenilin ability to rescue development, and the ablation of nicastrin, a γ-secretase component that is crucial for proteolytic activity, does not block development. The role of presenilins during Dictyostelium development is therefore independent of their proteolytic activity. However, presenilin loss in Dictyostelium results in elevated cyclic AMP (cAMP) levels and enhanced stimulation-induced calcium release, suggesting that presenilins regulate these intracellular signalling pathways. Our data suggest that presenilin proteins perform an ancient non-proteolytic role in regulating intracellular signalling and development, and that Dictyostelium is a useful model for analysing human presenilin function.
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Affiliation(s)
- Marthe H. R. Ludtmann
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London TW20 0EX, UK
| | - Grant P. Otto
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London TW20 0EX, UK
| | | | - Zhi-Hui Chen
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Claire Y. Allan
- Faculty of Science, Technology and Engineering, La Trobe University, Bundoora VIC 3086, Australia
| | - Selina Brace
- Centre for Ecology and Evolution, School of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
| | - Philip W. Beesley
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London TW20 0EX, UK
| | - Alan R. Kimmel
- NIDDK, National Institutes of Health, Bethesda, MD 20892, USA
| | - Paul Fisher
- Faculty of Science, Technology and Engineering, La Trobe University, Bundoora VIC 3086, Australia
| | - Richard Killick
- Institute of Psychiatry, King's College London, London SE5 8AF, UK
| | - Robin S. B. Williams
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London TW20 0EX, UK
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91
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Huesgen PF, Lange PF, Overall CM. Ensembles of protein termini and specific proteolytic signatures as candidate biomarkers of disease. Proteomics Clin Appl 2014; 8:338-50. [PMID: 24497460 DOI: 10.1002/prca.201300104] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 12/04/2013] [Accepted: 12/09/2013] [Indexed: 12/23/2022]
Abstract
Early accurate diagnosis and personalized treatment are essential in order to treat complex or fatal diseases such as cancer and autoimmune, cardiovascular and neurodegenerative diseases. To realize this vision, new diagnostic and prognostic biomarkers are urgently required. MS-based proteomics is the most promising approach for protein biomarker identification, but suffers in clinical translation of biomarker candidates that show only quantitative differences from normal tissue. Indeed, success in translating proteomic data to biomarkers in the clinic has been disappointing. Here, we propose that protein termini provide a new opportunity for biomarker discovery due to qualitative differences in intact and new protein termini between diseased and normal tissues. Altered proteolysis occurs in most pathologies. Disease- and process-specific protein modifications, including proteolytic processing and subsequent modification of the terminal amino acids, frequently lead to altered protein activity that plays key roles in the disease process. Thus, mapping of ensembles of characteristic protein termini provides a proteolytic signature of high information content that shows both quantitative and most importantly qualitative differences in different diseases and stage of disease. These unique protein biomarkers have the added benefit of being mechanistically informative by revealing the activity state of the bioactive protein. Moreover, proteome-wide isolation of protein termini leads to generalized sample simplification, thereby enabling up to three orders of magnitude lower LODs compared to traditional shotgun proteomic approaches. We introduce the potential of protein termini for biomarker discovery, briefly review methods enabling large-scale studies of protein termini, and discuss how these may be integrated into a termini-oriented biomarker discovery pipeline from discovery to clinical application.
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Affiliation(s)
- Pitter F Huesgen
- Centre for Blood Research, University of British Columbia, Vancouver, Canada; Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
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92
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Gudey SK, Wallenius A, Landström M. Regulated intramembrane proteolysis of the TGFβ type I receptor conveys oncogenic signals. Future Oncol 2014; 10:1853-61. [PMID: 24597658 DOI: 10.2217/fon.14.45] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Cancer cells produce high levels of TGFβ, a multipotent cytokine. Binding of TGFβ to its cell surface receptors, the transmembrane serine/threonine kinases TβRII and TβRI, causes phosphorylation and activation of intracellular latent Smad transcription factors. Nuclear Smads act in concert with specific transcription factors to reprogram epithelial cells to become invasive mesenchymal cells. TGFβ also propagates non-canonical signals, so it is crucial to have a better understanding of the underlying molecular mechanisms which favor this pathway. Here we highlight our recent discovery that TGFβ promotes the proteolytic cleavage of TβRI in cancer cells, resulting in the liberation and nuclear translocation of its intracellular domain, acting as co-regulator to transcribe pro-invasive genes. This newly identified oncogenic TGFβ pathway resembles the Notch signaling pathway. We discuss our findings in relation to Notch and provide a short overview of other growth factors that transduce signals via nuclear translocation of their cell surface receptors.
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Affiliation(s)
- Shyam Kumar Gudey
- Department of Medical Biosciences, Pathology, Umeå University, SE-901 85 Umeå, Sweden
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93
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Kanatsu K, Morohashi Y, Suzuki M, Kuroda H, Watanabe T, Tomita T, Iwatsubo T. Decreased CALM expression reduces Aβ42 to total Aβ ratio through clathrin-mediated endocytosis of γ-secretase. Nat Commun 2014; 5:3386. [PMID: 24577224 DOI: 10.1038/ncomms4386] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Accepted: 02/05/2014] [Indexed: 01/08/2023] Open
Abstract
A body of evidence suggests that aberrant metabolism of amyloid-β peptide (Aβ) underlies the aetiology of Alzheimer disease (AD). Recently, a single-nucleotide polymorphism in phosphatidylinositol binding clathrin assembly protein (PICALM/CALM) gene, which encodes a protein implicated in the clathrin-mediated endocytosis, was identified as a genetic protective factor for AD, although its mechanistic details have little been explored. Here we show that loss of CALM leads to the selective decrease in the production ratio of the pathogenic Aβ species, Aβ42. Active form of γ-secretase is constitutively endocytosed via the clathrin-mediated pathway in a CALM dependent manner. Alteration in the rate of clathrin-mediated endocytosis of γ-secretase causes a shift in its steady-state localization, which consequently impacts on the production ratio of Aβ42. Our study identifies CALM as an endogenous modulator of γ-secretase activity by regulating its endocytosis and also as an excellent target for Aβ42-lowering AD therapeutics.
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Affiliation(s)
- Kunihiko Kanatsu
- 1] Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan [2]
| | - Yuichi Morohashi
- 1] Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan [2] Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo 113-0033, Japan [3]
| | - Mai Suzuki
- Department of Biological Science, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan
| | - Hiromasa Kuroda
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Toshio Watanabe
- Department of Biological Science, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan
| | - Taisuke Tomita
- 1] Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan [2] Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo 113-0033, Japan
| | - Takeshi Iwatsubo
- 1] Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan [2] Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo 113-0033, Japan [3] Department of Neuropathology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
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94
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Morel E, Chamoun Z, Lasiecka ZM, Chan RB, Williamson RL, Vetanovetz C, Dall'Armi C, Simoes S, Point Du Jour KS, McCabe BD, Small SA, Di Paolo G. Phosphatidylinositol-3-phosphate regulates sorting and processing of amyloid precursor protein through the endosomal system. Nat Commun 2014; 4:2250. [PMID: 23907271 DOI: 10.1038/ncomms3250] [Citation(s) in RCA: 166] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 07/03/2013] [Indexed: 01/24/2023] Open
Abstract
Defects in endosomal sorting have been implicated in Alzheimer's disease. Endosomal traffic is largely controlled by phosphatidylinositol-3-phosphate, a phosphoinositide synthesized primarily by lipid kinase Vps34. Here we show that phosphatidylinositol-3-phosphate is selectively deficient in brain tissue from humans with Alzheimer's disease and Alzheimer's disease mouse models. Silencing Vps34 causes an enlargement of neuronal endosomes, enhances the amyloidogenic processing of amyloid precursor protein in these organelles and reduces amyloid precursor protein sorting to intraluminal vesicles. This trafficking phenotype is recapitulated by silencing components of the ESCRT (Endosomal Sorting Complex Required for Transport) pathway, including the phosphatidylinositol-3-phosphate effector Hrs and Tsg101. Amyloid precursor protein is ubiquitinated, and interfering with this process by targeted mutagenesis alters sorting of amyloid precursor protein to the intraluminal vesicles of endosomes and enhances amyloid-beta peptide generation. In addition to establishing phosphatidylinositol-3-phosphate deficiency as a contributing factor in Alzheimer's disease, these results clarify the mechanisms of amyloid precursor protein trafficking through the endosomal system in normal and pathological states.
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Affiliation(s)
- Etienne Morel
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, USA
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95
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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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96
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Dickey SW, Baker RP, Cho S, Urban S. Proteolysis inside the membrane is a rate-governed reaction not driven by substrate affinity. Cell 2014; 155:1270-81. [PMID: 24315097 DOI: 10.1016/j.cell.2013.10.053] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 08/04/2013] [Accepted: 10/28/2013] [Indexed: 10/25/2022]
Abstract
Enzymatic cleavage of transmembrane anchors to release proteins from the membrane controls diverse signaling pathways and is implicated in more than a dozen diseases. How catalysis works within the viscous, water-excluding, two-dimensional membrane is unknown. We developed an inducible reconstitution system to interrogate rhomboid proteolysis quantitatively within the membrane in real time. Remarkably, rhomboid proteases displayed no physiological affinity for substrates (K(d) ~190 μM/0.1 mol%). Instead, ~10,000-fold differences in proteolytic efficiency with substrate mutants and diverse rhomboid proteases were reflected in k(cat) values alone. Analysis of gate-open mutant and solvent isotope effects revealed that substrate gating, not hydrolysis, is rate limiting. Ultimately, a single proteolytic event within the membrane normally takes minutes. Rhomboid intramembrane proteolysis is thus a slow, kinetically controlled reaction not driven by transmembrane protein-protein affinity. These properties are unlike those of other studied proteases or membrane proteins but are strikingly reminiscent of one subset of DNA-repair enzymes, raising important mechanistic and drug-design implications.
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Affiliation(s)
- Seth W Dickey
- Howard Hughes Medical Institute, Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Room 507 PCTB, 725 North Wolfe Street, Baltimore, MD 21205, USA
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97
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Evin G, Barakat A. Critical analysis of the use of β-site amyloid precursor protein-cleaving enzyme 1 inhibitors in the treatment of Alzheimer's disease. Degener Neurol Neuromuscul Dis 2014; 4:1-19. [PMID: 32669897 PMCID: PMC7337240 DOI: 10.2147/dnnd.s41056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 03/06/2014] [Indexed: 01/18/2023] Open
Abstract
Alzheimer’s disease (AD) is the major cause of dementia in the elderly and an unmet clinical challenge. A variety of therapies that are currently under development are directed to the amyloid cascade. Indeed, the accumulation and toxicity of amyloid-β (Aβ) is believed to play a central role in the etiology of the disease, and thus rational interventions are aimed at reducing the levels of Aβ in the brain. Targeting β-site amyloid precursor protein-cleaving enzyme (BACE)-1 represents an attractive strategy, as this enzyme catalyzes the initial and rate-limiting step in Aβ production. Observation of increased levels of BACE1 and enzymatic activity in the brain, cerebrospinal fluid, and platelets of patients with AD and mild cognitive impairment supports the potential benefits of BACE1 inhibition. Numerous potent inhibitors have been generated, and many of these have been proved to lower Aβ levels in the brain of animal models. Over 10 years of intensive research on BACE1 inhibitors has now culminated in advancing half a dozen of these drugs into human trials, yet translating the in vitro and cellular efficacy of BACE1 inhibitors into preclinical and clinical trials represents a challenge. This review addresses the promises and also the potential problems associated with BACE1 inhibitors for AD therapy, as the complex biological function of BACE1 in the brain is becoming unraveled.
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Affiliation(s)
- Genevieve Evin
- Oxidation Biology Laboratory, Mental Health Research Institute, Florey Institute of Neuroscience and Mental Health, University of Melbourne.,Department of Pathology, University of Melbourne, Parkville, VIC, Australia
| | - Adel Barakat
- Department of Pathology, University of Melbourne, Parkville, VIC, Australia
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98
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Ohki Y, Shimada N, Tominaga A, Osawa S, Higo T, Yokoshima S, Fukuyama T, Tomita T, Iwatsubo T. Binding of longer Aβ to transmembrane domain 1 of presenilin 1 impacts on Aβ42 generation. Mol Neurodegener 2014; 9:7. [PMID: 24410857 PMCID: PMC3896738 DOI: 10.1186/1750-1326-9-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 01/10/2014] [Indexed: 11/18/2022] Open
Abstract
Background Amyloid-β peptide ending at 42nd residue (Aβ42) is believed as a pathogenic peptide for Alzheimer disease. Although γ-secretase is a responsible protease to generate Aβ through a processive cleavage, the proteolytic mechanism of γ-secretase at molecular level is poorly understood. Results We found that the transmembrane domain (TMD) 1 of presenilin (PS) 1, a catalytic subunit for the γ-secretase, as a key modulatory domain for Aβ42 production. Aβ42-lowering and -raising γ-secretase modulators (GSMs) directly targeted TMD1 of PS1 and affected its structure. A point mutation in TMD1 caused an aberrant secretion of longer Aβ species including Aβ45 that are the precursor of Aβ42. We further found that the helical surface of TMD1 is involved in the binding of Aβ45/48 and that the binding was altered by GSMs as well as TMD1 mutation. Conclusions Binding between PS1 TMD1 and longer Aβ is critical for Aβ42 production.
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Affiliation(s)
| | | | | | | | | | | | | | - Taisuke Tomita
- Department of Neuropathology and Neuroscience, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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99
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Bustamante HA, Rivera-Dictter A, Cavieres VA, Muñoz VC, González A, Lin Y, Mardones GA, Burgos PV. Turnover of C99 is controlled by a crosstalk between ERAD and ubiquitin-independent lysosomal degradation in human neuroglioma cells. PLoS One 2013; 8:e83096. [PMID: 24376644 PMCID: PMC3869756 DOI: 10.1371/journal.pone.0083096] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 11/06/2013] [Indexed: 12/28/2022] Open
Abstract
Alzheimer’s disease (AD) is characterized by the buildup of amyloid-β peptides (Aβ) aggregates derived from proteolytic processing of the β-amyloid precursor protein (APP). Amyloidogenic cleavage of APP by β-secretase/BACE1 generates the C-terminal fragment C99/CTFβ that can be subsequently cleaved by γ-secretase to produce Aβ. Growing evidence indicates that high levels of C99/CTFβ are determinant for AD. Although it has been postulated that γ-secretase-independent pathways must control C99/CTFβ levels, the contribution of organelles with degradative functions, such as the endoplasmic reticulum (ER) or lysosomes, is unclear. In this report, we investigated the turnover and amyloidogenic processing of C99/CTFβ in human H4 neuroglioma cells, and found that C99/CTFβ is localized at the Golgi apparatus in contrast to APP, which is mostly found in endosomes. Conditions that localized C99/CTFβ to the ER resulted in its degradation in a proteasome-dependent manner that first required polyubiquitination, consistent with an active role of the ER associated degradation (ERAD) in this process. Furthermore, when proteasomal activity was inhibited C99/CTFβ was degraded in a chloroquine (CQ)-sensitive compartment, implicating lysosomes as alternative sites for its degradation. Our results highlight a crosstalk between degradation pathways within the ER and lysosomes to avoid protein accumulation and toxicity.
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Affiliation(s)
- Hianara A. Bustamante
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Andrés Rivera-Dictter
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Viviana A. Cavieres
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Vanessa C. Muñoz
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Alexis González
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Yimo Lin
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Gonzalo A. Mardones
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
| | - Patricia V. Burgos
- Department of Physiology, School of Medicine and Centro de Investigación Sur-Austral en Enfermedades del Sistema Nervioso, Universidad Austral de Chile, Valdivia, Chile
- * E-mail:
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Acx H, Chávez-Gutiérrez L, Serneels L, Lismont S, Benurwar M, Elad N, De Strooper B. Signature amyloid β profiles are produced by different γ-secretase complexes. J Biol Chem 2013; 289:4346-55. [PMID: 24338474 DOI: 10.1074/jbc.m113.530907] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
γ-Secretase complexes are involved in the generation of amyloid-β (Aβ) in the brain. Therefore, γ-secretase has been proposed as a potential therapeutic target in Alzheimer disease (AD). Targeting γ-secretase activity in AD requires the pharmacological dissociation of the processing of physiological relevant substrates and the generation of "toxic" Aβ. Previous reports suggest the differential targeting of γ-secretase complexes, based on their subunit composition, as a valid strategy. However, little is known about the biochemical properties of the different complexes, and key questions regarding their Aβ product profiles should be first addressed. Here, we expressed, purified, and analyzed, under the same conditions, the endopeptidase and carboxypeptidase-like activities of the four γ-secretase complexes present in humans. We find that the nature of the catalytic subunit in the complex affects both activities. Interestingly, PSEN2 complexes discriminate between the Aβ40 and Aβ38 production lines, indicating that Aβ generation in one or the other pathway can be dissociated. In contrast, the APH1 subunit mainly affects the carboxypeptidase-like activity, with APH1B complexes favoring the generation of longer Aβ peptides. In addition, we determined that expression of a single human γ-secretase complex in cell lines retains the intrinsic attributes of the protease while present in the membrane, providing validation for the in vitro studies. In conclusion, our data show that each γ-secretase complex produces a characteristic Aβ signature. The qualitative and quantitative differences between different γ-secretase complexes could be used to advance drug development in AD and other disorders.
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Affiliation(s)
- Hermien Acx
- From the Center for the Biology of Disease, Flemish Institute for Biology (VIB), 3000 Leuven, Belgium
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