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Sun Y, Islam S, Gao Y, Nakamura T, Tomita T, Michikawa M, Zou K. Presenilin deficiency enhances tau phosphorylation and its secretion. J Neurochem 2024; 168:2956-2973. [PMID: 38946496 DOI: 10.1111/jnc.16155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 05/09/2024] [Accepted: 05/20/2024] [Indexed: 07/02/2024]
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of abnormally folded amyloid β-protein (Aβ) in the brain parenchyma and phosphorylated tau in neurons. Presenilin (PS, PSEN) 1 and PS2 are essential components of γ-secretase, which is responsible for the cleavage of amyloid precursor protein (APP) to generate Aβ. PSEN mutations are associated with tau aggregation in frontotemporal dementia, regardless of the presence or absence of Aβ pathology. However, the mechanism by which PS regulates tau aggregation is still unknown. Here, we found that tau phosphorylation and secretion were significantly increased in PS double-knock-out (PS1/2-/-) fibroblasts compared with wild-type fibroblasts. Tau-positive vesicles in the cytoplasm were significantly increased in PS1/2-/- fibroblasts. Active GSK-3β was increased in PS1/2-/- fibroblasts, and inhibiting GSK3β activity in PS1/2-/- fibroblasts resulted in decreased tau phosphorylation and secretion. Transfection of WT human PS1 and PS2 reduced the secretion of phosphorylated tau and active GSK-3β in PS1/2-/- fibroblasts. However, PS1D257A without γ-secretase activity did not decrease the secretion of phosphorylated tau. Furthermore, nicastrin deficiency also increased tau phosphorylation and secretion. These results suggest that deficient PS complex maturation may increase tau phosphorylation and secretion. Thus, our studies discover a new pathway by which PS regulates tau phosphorylation/secretion and pathology independent of Aβ and suggest that PS serves as a potential therapeutic target for treating neurodegenerative diseases involving tau aggregation.
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Affiliation(s)
- Yang Sun
- Department of Biochemistry, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Sadequl Islam
- Department of Biochemistry, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Yuan Gao
- Department of Biochemistry, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Tomohisa Nakamura
- Department of Biochemistry, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Taisuke Tomita
- Laboratory of Neuropathology and Neuroscience, Faculty of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Makoto Michikawa
- Department of Geriatric Medicine, School of Life Dentistry at Niigata, The Nippon Dental University, Niigata, Japan
| | - Kun Zou
- Department of Biochemistry, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
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2
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Ajore R, Mattsson J, Pertesi M, Ekdahl L, Ali Z, Hansson M, Nilsson B. Genome-wide CRISPR/Cas9 screen identifies regulators of BCMA expression on multiple myeloma cells. Blood Cancer J 2024; 14:21. [PMID: 38272874 PMCID: PMC10811322 DOI: 10.1038/s41408-024-00986-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/06/2024] [Accepted: 01/09/2024] [Indexed: 01/27/2024] Open
Affiliation(s)
- Ram Ajore
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, 221 84, Lund, Sweden
- Lund Stem Cell Center, Lund University, 221 84, Lund, Sweden
| | - Jenny Mattsson
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, 221 84, Lund, Sweden
- Lund Stem Cell Center, Lund University, 221 84, Lund, Sweden
- BioInvent International AB, Ideongatan 1, 223 70, Lund, Sweden
| | - Maroulio Pertesi
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, 221 84, Lund, Sweden
- Lund Stem Cell Center, Lund University, 221 84, Lund, Sweden
| | - Ludvig Ekdahl
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, 221 84, Lund, Sweden
- Lund Stem Cell Center, Lund University, 221 84, Lund, Sweden
| | - Zain Ali
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, 221 84, Lund, Sweden
- Lund Stem Cell Center, Lund University, 221 84, Lund, Sweden
| | - Markus Hansson
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, 221 84, Lund, Sweden
- Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, Göteborg University, 41346, Göteborg, Sweden
| | - Björn Nilsson
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University, 221 84, Lund, Sweden.
- Lund Stem Cell Center, Lund University, 221 84, Lund, Sweden.
- Broad Institute, Cambridge, MA, 02142, USA.
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3
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Samanta S, Chakraborty S, Bagchi D. Pathogenesis of Neurodegenerative Diseases and the Protective Role of Natural Bioactive Components. JOURNAL OF THE AMERICAN NUTRITION ASSOCIATION 2024; 43:20-32. [PMID: 37186678 DOI: 10.1080/27697061.2023.2203235] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 04/11/2023] [Indexed: 05/17/2023]
Abstract
Neurodegenerative diseases are a serious problem throughout the world. There are several causes of neurodegenerative diseases; these include genetic predisposition, accumulation of misfolded proteins, oxidative stress, neuroinflammation, and excitotoxicity. Oxidative stress increases the production of reactive oxygen species (ROS) that advance lipid peroxidation, DNA damage, and neuroinflammation. The cellular antioxidant system (superoxide dismutase, catalase, peroxidase, and reduced glutathione) plays a crucial role in scavenging free radicals. An imbalance in the defensive actions of antioxidants and overproduction of ROS intensify neurodegeneration. The formation of misfolded proteins, glutamate toxicity, oxidative stress, and cytokine imbalance promote the pathogenesis of Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Antioxidants are now attractive molecules to fight against neurodegeneration. Certain vitamins (A, E, C) and polyphenolic compounds (flavonoids) show excellent antioxidant properties. Diet is the major source of antioxidants. However, diet medicinal herbs are also rich sources of numerous flavonoids. Antioxidants prevent ROS-mediated neuronal degeneration in post-oxidative stress conditions. The present review is focused on the pathogenesis of neurodegenerative diseases and the protective role of antioxidants. KEY TEACHING POINTSThis review shows that multiple factors are directly or indirectly associated with the pathogenesis of neurodegenerative diseases.Failure to cellular antioxidant capacity increases oxidative stress that intensifies neuroinflammation and disease progression.Different vitamins, carotenoids, and flavonoids, having antioxidant capacity, can be considered protective agents.
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Affiliation(s)
- Saptadip Samanta
- Department of Physiology, Midnapore College, Midnapore, West Bengal, India
| | - Sanjoy Chakraborty
- Department of Biological Sciences, New York City College of Technology/CUNY, Brooklyn, New York, USA
| | - Debasis Bagchi
- Department of Biology, College of Arts and Sciences, Adelphi University, Garden City, New York, USA
- Department of Psychology, Gordon F. Derner School of Psychology, Adelphi University, Garden City, New York, USA
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4
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Banerjee R, Gunawardena S. Glycogen synthase kinase 3β (GSK3β) and presenilin (PS) are key regulators of kinesin-1-mediated cargo motility within axons. Front Cell Dev Biol 2023; 11:1202307. [PMID: 37363727 PMCID: PMC10288942 DOI: 10.3389/fcell.2023.1202307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 05/25/2023] [Indexed: 06/28/2023] Open
Abstract
It has been a quarter century since the discovery that molecular motors are phosphorylated, but fundamental questions still remain as to how specific kinases contribute to particular motor functions, particularly in vivo, and to what extent these processes have been evolutionarily conserved. Such questions remain largely unanswered because there is no cohesive strategy to unravel the likely complex spatial and temporal mechanisms that control motility in vivo. Since diverse cargoes are transported simultaneously within cells and along narrow long neurons to maintain intracellular processes and cell viability, and disruptions in these processes can lead to cancer and neurodegeneration, there is a critical need to better understand how kinases regulate molecular motors. Here, we review our current understanding of how phosphorylation can control kinesin-1 motility and provide evidence for a novel regulatory mechanism that is governed by a specific kinase, glycogen synthase kinase 3β (GSK3β), and a scaffolding protein presenilin (PS).
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Affiliation(s)
- Rupkatha Banerjee
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, United States
| | - Shermali Gunawardena
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY, United States
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5
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Importance of GWAS in finding un-targeted genetic association of sporadic Alzheimer’s disease. Mol Cell Toxicol 2021. [DOI: 10.1007/s13273-021-00130-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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6
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Buniatian GH, Weiskirchen R, Weiss TS, Schwinghammer U, Fritz M, Seferyan T, Proksch B, Glaser M, Lourhmati A, Buadze M, Borkham-Kamphorst E, Gaunitz F, Gleiter CH, Lang T, Schaeffeler E, Tremmel R, Cynis H, Frey WH, Gebhardt R, Friedman SL, Mikulits W, Schwab M, Danielyan L. Antifibrotic Effects of Amyloid-Beta and Its Loss in Cirrhotic Liver. Cells 2020; 9:cells9020452. [PMID: 32089540 PMCID: PMC7072823 DOI: 10.3390/cells9020452] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/06/2020] [Accepted: 02/13/2020] [Indexed: 12/15/2022] Open
Abstract
The function and regulation of amyloid-beta (Aβ) in healthy and diseased liver remains unexplored. Because Aβ reduces the integrity of the blood-brain barrier we have examined its potential role in regulating the sinusoidal permeability of normal and cirrhotic liver. Aβ and key proteins that generate (beta-secretase 1 and presenilin-1) and degrade it (neprilysin and myelin basic protein) were decreased in human cirrhotic liver. In culture, activated hepatic stellate cells (HSC) internalized Aβ more efficiently than astrocytes and HSC degraded Aβ leading to suppressed expression of α-smooth muscle actin (α-SMA), collagen 1 and transforming growth factor β (TGFβ). Aβ also upregulated sinusoidal permeability marker endothelial NO synthase (eNOS) and decreased TGFβ in cultured human liver sinusoidal endothelial cells (hLSEC). Liver Aβ levels also correlate with the expression of eNOS in transgenic Alzheimer’s disease mice and in human and rodent cirrhosis/fibrosis. These findings suggest a previously unexplored role of Aβ in the maintenance of liver sinusoidal permeability and in protection against cirrhosis/fibrosis via attenuation of HSC activation.
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Affiliation(s)
- Gayane Hrachia Buniatian
- Department of Clinical Pharmacology, University Hospital of Tübingen, 72076 Tübingen, Germany; (U.S.); (M.F.); (B.P.); (M.G.); (A.L.); (M.B.); (C.H.G.); (M.S.)
- H. Buniatian Institute of Biochemistry, National Academy of Sciences of the Republic of Armenia (NAS RA), Yerevan 0014, Armenia;
- Correspondence: (G.H.B.); (L.D.)
| | - Ralf Weiskirchen
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH University Hospital Aachen, 52074 Aachen, Germany; (R.W.); (E.B.-K.)
| | - Thomas S. Weiss
- Children’s University Hospital (KUNO), University of Regensburg, 93053 Regensburg, Germany;
| | - Ute Schwinghammer
- Department of Clinical Pharmacology, University Hospital of Tübingen, 72076 Tübingen, Germany; (U.S.); (M.F.); (B.P.); (M.G.); (A.L.); (M.B.); (C.H.G.); (M.S.)
| | - Martin Fritz
- Department of Clinical Pharmacology, University Hospital of Tübingen, 72076 Tübingen, Germany; (U.S.); (M.F.); (B.P.); (M.G.); (A.L.); (M.B.); (C.H.G.); (M.S.)
| | - Torgom Seferyan
- H. Buniatian Institute of Biochemistry, National Academy of Sciences of the Republic of Armenia (NAS RA), Yerevan 0014, Armenia;
| | - Barbara Proksch
- Department of Clinical Pharmacology, University Hospital of Tübingen, 72076 Tübingen, Germany; (U.S.); (M.F.); (B.P.); (M.G.); (A.L.); (M.B.); (C.H.G.); (M.S.)
| | - Michael Glaser
- Department of Clinical Pharmacology, University Hospital of Tübingen, 72076 Tübingen, Germany; (U.S.); (M.F.); (B.P.); (M.G.); (A.L.); (M.B.); (C.H.G.); (M.S.)
| | - Ali Lourhmati
- Department of Clinical Pharmacology, University Hospital of Tübingen, 72076 Tübingen, Germany; (U.S.); (M.F.); (B.P.); (M.G.); (A.L.); (M.B.); (C.H.G.); (M.S.)
| | - Marine Buadze
- Department of Clinical Pharmacology, University Hospital of Tübingen, 72076 Tübingen, Germany; (U.S.); (M.F.); (B.P.); (M.G.); (A.L.); (M.B.); (C.H.G.); (M.S.)
| | - Erawan Borkham-Kamphorst
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, RWTH University Hospital Aachen, 52074 Aachen, Germany; (R.W.); (E.B.-K.)
| | - Frank Gaunitz
- Department of Neurosurgery, University Hospital of Leipzig, 04103 Leipzig, Germany;
| | - Christoph H. Gleiter
- Department of Clinical Pharmacology, University Hospital of Tübingen, 72076 Tübingen, Germany; (U.S.); (M.F.); (B.P.); (M.G.); (A.L.); (M.B.); (C.H.G.); (M.S.)
| | - Thomas Lang
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, 70376 Stuttgart, Germany, and University of Tuebingen, 72076 Tuebingen, Germany; (T.L.); (E.S.); (R.T.)
| | - Elke Schaeffeler
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, 70376 Stuttgart, Germany, and University of Tuebingen, 72076 Tuebingen, Germany; (T.L.); (E.S.); (R.T.)
| | - Roman Tremmel
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, 70376 Stuttgart, Germany, and University of Tuebingen, 72076 Tuebingen, Germany; (T.L.); (E.S.); (R.T.)
| | - Holger Cynis
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, 06120 Halle, Germany;
| | - William H. Frey
- Center for Memory & Aging, HealthPartners Neuroscience Center, St. Paul, MN 55130, USA;
| | - Rolf Gebhardt
- Rudolf-Schönheimer Institute of Biochemistry, Faculty of Medicine, University of Leipzig, 04103 Leipzig, Germany;
| | - Scott L. Friedman
- Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA;
| | - Wolfgang Mikulits
- Department of Medicine I, Institute of Cancer Research, Comprehensive Cancer Center, Medical University of Vienna, Vienna 1090, Austria;
| | - Matthias Schwab
- Department of Clinical Pharmacology, University Hospital of Tübingen, 72076 Tübingen, Germany; (U.S.); (M.F.); (B.P.); (M.G.); (A.L.); (M.B.); (C.H.G.); (M.S.)
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, 70376 Stuttgart, Germany, and University of Tuebingen, 72076 Tuebingen, Germany; (T.L.); (E.S.); (R.T.)
- Department of Pharmacy and Biochemistry, University of Tuebingen, 72076 Tuebingen, Germany
- Departments of Biochemistry and Clinical Pharmacology, and Neuroscience Laboratory, Yerevan State Medical University, Yerevan 0025, Armenia
| | - Lusine Danielyan
- Department of Clinical Pharmacology, University Hospital of Tübingen, 72076 Tübingen, Germany; (U.S.); (M.F.); (B.P.); (M.G.); (A.L.); (M.B.); (C.H.G.); (M.S.)
- Departments of Biochemistry and Clinical Pharmacology, and Neuroscience Laboratory, Yerevan State Medical University, Yerevan 0025, Armenia
- Correspondence: (G.H.B.); (L.D.)
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In-vitro studies of curcumin encapsulated mesoporous Fe-Phenanthroline nanocluster for reduction of amyloid β plaque. J Drug Deliv Sci Technol 2019. [DOI: 10.1016/j.jddst.2019.101314] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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Ivetic A, Hoskins Green HL, Hart SJ. L-selectin: A Major Regulator of Leukocyte Adhesion, Migration and Signaling. Front Immunol 2019; 10:1068. [PMID: 31139190 PMCID: PMC6527602 DOI: 10.3389/fimmu.2019.01068] [Citation(s) in RCA: 268] [Impact Index Per Article: 53.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 04/26/2019] [Indexed: 12/12/2022] Open
Abstract
L-selectin (CD62L) is a type-I transmembrane glycoprotein and cell adhesion molecule that is expressed on most circulating leukocytes. Since its identification in 1983, L-selectin has been extensively characterized as a tethering/rolling receptor. There is now mounting evidence in the literature to suggest that L-selectin plays a role in regulating monocyte protrusion during transendothelial migration (TEM). The N-terminal calcium-dependent (C-type) lectin domain of L-selectin interacts with numerous glycans, including sialyl Lewis X (sLex) for tethering/rolling and proteoglycans for TEM. Although the signals downstream of L-selectin-dependent adhesion are poorly understood, they will invariably involve the short 17 amino acid cytoplasmic tail. In this review we will detail the expression of L-selectin in different immune cell subsets, and its influence on cell behavior. We will list some of the diverse glycans known to support L-selectin-dependent adhesion, within luminal and abluminal regions of the vessel wall. We will describe how each domain within L-selectin contributes to adhesion, migration and signal transduction. A significant focus on the L-selectin cytoplasmic tail and its proposed contribution to signaling via the ezrin-radixin-moesin (ERM) family of proteins will be outlined. Finally, we will discuss how ectodomain shedding of L-selectin during monocyte TEM is essential for the establishment of front-back cell polarity, bestowing emigrated cells the capacity to chemotax toward sites of damage.
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Affiliation(s)
- Aleksandar Ivetic
- King's College London, School of Cardiovascular Medicine and Sciences, BHF Center of Research Excellence, London, United Kingdom
| | - Hannah Louise Hoskins Green
- King's College London, School of Cardiovascular Medicine and Sciences, BHF Center of Research Excellence, London, United Kingdom
| | - Samuel James Hart
- King's College London, School of Cardiovascular Medicine and Sciences, BHF Center of Research Excellence, London, United Kingdom
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9
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Banerjee R, Rudloff Z, Naylor C, Yu MC, Gunawardena S. The presenilin loop region is essential for glycogen synthase kinase 3 β (GSK3β) mediated functions on motor proteins during axonal transport. Hum Mol Genet 2019; 27:2986-3001. [PMID: 29790963 DOI: 10.1093/hmg/ddy190] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 05/10/2018] [Indexed: 01/05/2023] Open
Abstract
Neurons require intracellular transport of essential components for function and viability and defects in transport has been implicated in many neurodegenerative diseases including Alzheimer's disease (AD). One possible mechanism by which transport defects could occur is by improper regulation of molecular motors. Previous work showed that reduction of presenilin (PS) or glycogen synthase kinase 3 beta (GSK3β) stimulated amyloid precursor protein vesicle motility. Excess GSK3β caused transport defects and increased motor binding to membranes, while reduction of PS decreased active GSK3β and motor binding to membranes. Here, we report that functional PS and the catalytic loop region of PS is essential for the rescue of GSK3β-mediated axonal transport defects. Disruption of PS loop (PSΔE9) or expression of the non-functional PS variant, PSD447A, failed to rescue axonal blockages in vivo. Further, active GSK3β associated with and phosphorylated kinesin-1 in vitro. Our observations together with previous work that showed that the loop region of PS interacts with GSK3β propose a scaffolding mechanism for PS in which the loop region sequesters GSK3β away from motors for the proper regulation of motor function. These findings are important to uncouple the complex regulatory mechanisms that likely exist for motor activity during axonal transport in vivo.
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Affiliation(s)
- Rupkatha Banerjee
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Zoe Rudloff
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Crystal Naylor
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Michael C Yu
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Shermali Gunawardena
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, NY 14260, USA
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10
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Asavapanumas N, Brawek B, Martus P, Garaschuk O. Role of intracellular Ca2+ stores for an impairment of visual processing in a mouse model of Alzheimer's disease. Neurobiol Dis 2019; 121:315-326. [DOI: 10.1016/j.nbd.2018.10.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 09/28/2018] [Accepted: 10/22/2018] [Indexed: 12/21/2022] Open
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11
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Signal peptide peptidase and SPP-like proteases - Possible therapeutic targets? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017. [PMID: 28624439 DOI: 10.1016/j.bbamcr.2017.06.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Signal peptide peptidase (SPP) and the four homologous SPP-like proteases SPPL2a, SPPL2b, SPPL2c and SPPL3 are GxGD-type intramembrane-cleaving proteases (I-CLIPs). In addition to divergent subcellular localisations, distinct differences in the mechanistic properties and substrate requirements of individual family members have been unravelled. SPP/SPPL proteases employ a catalytic mechanism related to that of the γ-secretase complex. Nevertheless, differential targeting of SPP/SPPL proteases and γ-secretase by inhibitors has been demonstrated. Furthermore, also within the SPP/SPPL family significant differences in the sensitivity to currently available inhibitory compounds have been reported. Though far from complete, our knowledge on pathophysiological functions of SPP/SPPL proteases, in particular based on studies in mice, has been significantly increased over the last years. Based on this, inhibition of distinct SPP/SPPL proteases has been proposed as a novel therapeutic concept e.g. for the treatment of autoimmunity and viral or protozoal infections, as we will discuss in this review. This article is part of a Special Issue entitled: Proteolysis as a Regulatory Event in Pathophysiology edited by Stefan Rose-John.
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12
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Grigorenko AP, Moliaka YK, Plotnikova OV, Smirnov A, Nikishina VA, Goltsov AY, Gusev F, Andreeva TV, Nelson O, Bezprozvanny I, Rogaev EI. Mutational re-modeling of di-aspartyl intramembrane proteases: uncoupling physiologically-relevant activities from those associated with Alzheimer's disease. Oncotarget 2017; 8:82006-82026. [PMID: 29137240 PMCID: PMC5669866 DOI: 10.18632/oncotarget.18299] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 04/28/2017] [Indexed: 12/18/2022] Open
Abstract
The intramembrane proteolytic activities of presenilins (PSEN1/PS1 and PSEN2/PS2) underlie production of β-amyloid, the key process in Alzheimer’s disease (AD). Dysregulation of presenilin-mediated signaling is linked to cancers. Inhibition of the γ-cleavage activities of PSENs that produce Aβ, but not the ε-like cleavage activity that release physiologically essential transcription activators, is a potential approach for the development of rational therapies for AD. In order to identify whether different activities of PSEN1 can be dissociated, we designed multiple mutations in the evolutionary conserved sites of PSEN1. We tested them in vitro and in vivo assays and compared their activities with mutant isoforms of presenilin-related intramembrane di-aspartyl protease (IMPAS1 (IMP1)/signal peptide peptidase (SPP)). PSEN1 auto-cleavage was more resistant to the mutation remodeling than the ε-like proteolysis. PSEN1 with a G382A or a P433A mutation in evolutionary invariant sites retains functionally important APP ε- and Notch S3- cleavage activities, but G382A inhibits APP γ-cleavage and Aβ production and a P433A elevates Aβ. The G382A variant cannot restore the normal cellular ER Ca2+ leak in PSEN1/PSEN2 double knockout cells, but efficiently rescues the loss-of-function (Egl) phenotype of presenilin in C. elegans. We found that, unlike in PSEN1 knockout cells, endoplasmic reticulum (ER) Ca2+ leak is not changed in the absence of IMP1/SPP. IMP1/SPP with the analogous mutations retained efficiency in cleavage of transmembrane substrates and rescued the lethality of Ce-imp-2 knockouts. In summary, our data show that mutations near the active catalytic sites of intramembrane di-aspartyl proteases have different consequences on proteolytic and signaling functions.
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Affiliation(s)
- Anastasia P Grigorenko
- Department of Psychiatry, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA 01604, USA.,Department of Genomics and Human Genetics, Institute of General Genetics, Russian Academy of Sciences, Moscow, 119991 Russia.,Center for Brain Neurobiology and Neurogenetics, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Youri K Moliaka
- Department of Psychiatry, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Olga V Plotnikova
- Department of Psychiatry, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Alexander Smirnov
- Department of Psychiatry, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Vera A Nikishina
- Department of Psychiatry, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Andrey Y Goltsov
- Department of Genomics and Human Genetics, Institute of General Genetics, Russian Academy of Sciences, Moscow, 119991 Russia.,Center for Brain Neurobiology and Neurogenetics, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Fedor Gusev
- Department of Genomics and Human Genetics, Institute of General Genetics, Russian Academy of Sciences, Moscow, 119991 Russia.,Center for Brain Neurobiology and Neurogenetics, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Tatiana V Andreeva
- Department of Genomics and Human Genetics, Institute of General Genetics, Russian Academy of Sciences, Moscow, 119991 Russia.,Center for Brain Neurobiology and Neurogenetics, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Omar Nelson
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9040, USA
| | - Ilya Bezprozvanny
- Department of Physiology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9040, USA
| | - Evgeny I Rogaev
- Department of Psychiatry, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA 01604, USA.,Department of Genomics and Human Genetics, Institute of General Genetics, Russian Academy of Sciences, Moscow, 119991 Russia.,Center for Brain Neurobiology and Neurogenetics, Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia.,Center for Genetics and Genetic Technologies, Faculty of Biology, Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia
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13
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Palop JJ, Mucke L. Network abnormalities and interneuron dysfunction in Alzheimer disease. Nat Rev Neurosci 2016; 17:777-792. [PMID: 27829687 DOI: 10.1038/nrn.2016.141] [Citation(s) in RCA: 618] [Impact Index Per Article: 77.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The function of neural circuits and networks can be controlled, in part, by modulating the synchrony of their components' activities. Network hypersynchrony and altered oscillatory rhythmic activity may contribute to cognitive abnormalities in Alzheimer disease (AD). In this condition, network activities that support cognition are altered decades before clinical disease onset, and these alterations predict future pathology and brain atrophy. Although the precise causes and pathophysiological consequences of these network alterations remain to be defined, interneuron dysfunction and network abnormalities have emerged as potential mechanisms of cognitive dysfunction in AD and related disorders. Here, we explore the concept that modulating these mechanisms may help to improve brain function in these conditions.
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Affiliation(s)
- Jorge J Palop
- Gladstone Institute of Neurological Disease, 1650 Owens Street, San Francisco, California 94158, USA.,Department of Neurology, University of California, San Francisco, 1650 Owens Street, San Francisco, California 94158, USA
| | - Lennart Mucke
- Gladstone Institute of Neurological Disease, 1650 Owens Street, San Francisco, California 94158, USA.,Department of Neurology, University of California, San Francisco, 1650 Owens Street, San Francisco, California 94158, USA
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14
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Proteolytic processing of Neuregulin-1. Brain Res Bull 2016; 126:178-182. [PMID: 27393467 DOI: 10.1016/j.brainresbull.2016.07.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 06/28/2016] [Accepted: 07/03/2016] [Indexed: 02/07/2023]
Abstract
Neuregulin-1 (NRG1), known also as heregulin, acetylcholine receptor inducing activity (ARIA), glial growth factor (GGF), or sensory and motor neuron derived factor (SMDF), is a key factor for many developmental processes and in adult brain. All known splice variants contain an epidermal growth factor (EGF)-like domain, which is mediating signaling via receptors of the ErbB family. In particular, NRG1 acts as an essential signaling molecule expressed on the axonal surface, where it signals to Schwann cells throughout development and regulates the thickness of the myelin sheath. NRG1 is required also by other cell types in the nervous system, for instance as an axonal signal released by proprioceptive afferents to induce development of the muscle spindle, and it controls aspects of cortical interneuron development as well as the formation of thalamo-cortical projections. The precursor protein of NRG1 can be activated and released from the membrane through limited proteolysis by the β-Secretase (β-site amyloid precursor protein cleaving enzyme 1, BACE1) which was first identified through its function as the rate limiting enzyme of amyloid-β-peptide (Aβ) production. Aβ is the major component of amyloid plaques in Alzheimer's disease (AD). Due to the hairpin nature of NRG1 type III two membrane-bound stubs with a type 1 and a type 2 orientation are generated by an initial proteolytic cleavage and successive release of the EGF-like domain either by dual cleavage by BACE1 or by ADAM17 (a disintegrin and metalloprotease) which is also called TACE (Tumor Necrosis Factor-α-converting enzyme). The cleavages activate NRG1 to allow juxtacrine or paracrine signaling. The type 1 oriented stub is further cleaved by γ-secretase in the transmembrane domain with a putative role in intracellular domain (ICD) signaling, while the type II oriented stub is cleaved by signal peptidase like proteases (SPPLs). Neuregulin-1 was identified as a major physiological substrate of BACE1 during early postnatal development when similarities in BACE1 KO mice and NRG1 heterozygous mice were discovered. Both display severe hypomyelination of peripheral nerves. Later it was shown with genetic and pharmacological evidence that the developmental effect of type I NRG1 on the formation and the maintenance of muscle spindles is BACE1 dependent. Thus, NRG1 functions in PNS and CNS are likely to set limits to an Alzheimer disease therapy with relatively strong BACE1 inhibition.
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15
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Coburger I, Schaub Y, Roeser D, Hardes K, Maeder P, Klee N, Steinmetzer T, Imhof D, Diederich WE, Than ME. Identification of inhibitors of the transmembrane protease FlaK of Methanococcus maripaludis. Microbiologyopen 2016; 5:637-46. [PMID: 27038342 PMCID: PMC4985597 DOI: 10.1002/mbo3.358] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 02/23/2016] [Accepted: 03/07/2016] [Indexed: 01/17/2023] Open
Abstract
GxGD‐type intramembrane cleaving proteases (I‐CLiPs) form a family of proteolytic enzymes that feature an aspartate‐based catalytic mechanism. Yet, they structurally and functionally largely differ from the classical pepsin‐like aspartic proteases. Among them are the archaeal enzyme FlaK, processing its substrate FlaB2 during the formation of flagella and γ‐secretase, which is centrally involved in the etiology of the neurodegenerative Alzheimer's disease. We developed an optimized activity assay for FlaK and based on screening of a small in‐house library and chemical synthesis, we identified compound 9 as the first inhibitor of this enzyme. Our results show that this intramembrane protease differs from classical pepsin‐like aspartic proteases and give insights into the substrate recognition of this enzyme. By providing the needed tools to further study the enzymatic cycle of FlaK, our results also enable further studies towards a functional understanding of other GxGD‐type I‐CLiPs.
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Affiliation(s)
- Ina Coburger
- Leibniz Institute on Aging (FLI), Protein Crystallography Group, Beutenbergstr. 11, Jena, 07745, Germany
| | - Yvonne Schaub
- Leibniz Institute on Aging (FLI), Protein Crystallography Group, Beutenbergstr. 11, Jena, 07745, Germany
| | - Dirk Roeser
- Leibniz Institute on Aging (FLI), Protein Crystallography Group, Beutenbergstr. 11, Jena, 07745, Germany
| | - Kornelia Hardes
- Department of Pharmaceutical Chemistry, Philipps University Marburg, Marbacher Weg 6, Marburg, 35032, Germany
| | - Patrick Maeder
- Department of Pharmaceutical Chemistry, Philipps University Marburg, Marbacher Weg 6, Marburg, 35032, Germany
| | - Nina Klee
- Department of Pharmaceutical Chemistry, Philipps University Marburg, Marbacher Weg 6, Marburg, 35032, Germany
| | - Torsten Steinmetzer
- Department of Pharmaceutical Chemistry, Philipps University Marburg, Marbacher Weg 6, Marburg, 35032, Germany
| | - Diana Imhof
- Institute of Pharmacy, Pharmaceutical Chemistry I, University of Bonn, Brühler Str. 7, Bonn, 53119, Germany
| | - Wibke E Diederich
- Department of Pharmaceutical Chemistry, Philipps University Marburg, Marbacher Weg 6, Marburg, 35032, Germany
| | - Manuel E Than
- Leibniz Institute on Aging (FLI), Protein Crystallography Group, Beutenbergstr. 11, Jena, 07745, Germany
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16
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Fleck D, Voss M, Brankatschk B, Giudici C, Hampel H, Schwenk B, Edbauer D, Fukumori A, Steiner H, Kremmer E, Haug-Kröper M, Rossner MJ, Fluhrer R, Willem M, Haass C. Proteolytic Processing of Neuregulin 1 Type III by Three Intramembrane-cleaving Proteases. J Biol Chem 2015; 291:318-33. [PMID: 26574544 DOI: 10.1074/jbc.m115.697995] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Indexed: 12/22/2022] Open
Abstract
Numerous membrane-bound proteins undergo regulated intramembrane proteolysis. Regulated intramembrane proteolysis is initiated by shedding, and the remaining stubs are further processed by intramembrane-cleaving proteases (I-CLiPs). Neuregulin 1 type III (NRG1 type III) is a major physiological substrate of β-secretase (β-site amyloid precursor protein-cleaving enzyme 1 (BACE1)). BACE1-mediated cleavage is required to allow signaling of NRG1 type III. Because of the hairpin nature of NRG1 type III, two membrane-bound stubs with a type 1 and a type 2 orientation are generated by proteolytic processing. We demonstrate that these stubs are substrates for three I-CLiPs. The type 1-oriented stub is further cleaved by γ-secretase at an ϵ-like site five amino acids N-terminal to the C-terminal membrane anchor and at a γ-like site in the middle of the transmembrane domain. The ϵ-cleavage site is only one amino acid N-terminal to a Val/Leu substitution associated with schizophrenia. The mutation reduces generation of the NRG1 type III β-peptide as well as reverses signaling. Moreover, it affects the cleavage precision of γ-secretase at the γ-site similar to certain Alzheimer disease-associated mutations within the amyloid precursor protein. The type 2-oriented membrane-retained stub of NRG1 type III is further processed by signal peptide peptidase-like proteases SPPL2a and SPPL2b. Expression of catalytically inactive aspartate mutations as well as treatment with 2,2'-(2-oxo-1,3-propanediyl)bis[(phenylmethoxy)carbonyl]-l-leucyl-l-leucinamide ketone inhibits formation of N-terminal intracellular domains and the corresponding secreted C-peptide. Thus, NRG1 type III is the first protein substrate that is not only cleaved by multiple sheddases but is also processed by three different I-CLiPs.
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Affiliation(s)
- Daniel Fleck
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich
| | - Matthias Voss
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich
| | - Ben Brankatschk
- the Department of Molecular Neurobiology, Clinic for Psychiatry, Ludwig-Maximilians-University Munich, 80336 Munich
| | - Camilla Giudici
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich
| | - Heike Hampel
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich
| | - Benjamin Schwenk
- the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich
| | - Dieter Edbauer
- the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich, the Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, and
| | - Akio Fukumori
- the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich
| | - Harald Steiner
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich, the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich
| | - Elisabeth Kremmer
- the Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, and the Institute of Molecular Immunology, Helmholtz Center Munich, 81377 Munich, Germany
| | - Martina Haug-Kröper
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich
| | - Moritz J Rossner
- the Department of Molecular Neurobiology, Clinic for Psychiatry, Ludwig-Maximilians-University Munich, 80336 Munich
| | - Regina Fluhrer
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich, the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich
| | - Michael Willem
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich,
| | - Christian Haass
- From the Biomedical Center, Biochemistry, Ludwig-Maximilians-University Munich, 81377 Munich, the German Center for Neurodegenerative Diseases (DZNE), Munich, 81377 Munich, the Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, and
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17
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Part K, Künnis-Beres K, Poska H, Land T, Shimmo R, Zetterström Fernaeus S. Amyloid β25-35 induced ROS-burst through NADPH oxidase is sensitive to iron chelation in microglial Bv2 cells. Brain Res 2015; 1629:282-90. [PMID: 26505916 DOI: 10.1016/j.brainres.2015.09.034] [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: 05/09/2015] [Revised: 09/28/2015] [Accepted: 09/29/2015] [Indexed: 11/27/2022]
Abstract
Iron chelation therapy and inhibition of glial nicotinamide adenine dinucleotide phosphate (NADPH) oxidase can both represent possible routes for Alzheimer's disease modifying therapies. The metal hypothesis is largely focused on direct binding of metals to the N-terminal hydrophilic 1-16 domain peptides of Amyloid beta (Aβ) and how they jointly give rise to reactive oxygen species (ROS) production. The cytotoxic effects of Aβ through ROS and metals are mainly studied in neuronal cells using full-length Aβ1-40/42 peptides. Here we study cellularly-derived ROS during 2-60min in response to non-metal associated mid domain Aβ25-35 in microglial Bv2 cells by fluorescence based spectroscopy. We analyze if Aβ25-35 induce ROS production through NADPH oxidase and if the production is sensitive to iron chelation. NADPH oxidase inhibitor diphenyliodonium (DPI) is used to confirm the production of ROS through NADPH oxidase. We modulate cellular iron homeostasis by applying cell permeable iron chelators desferrioxamine (DFO) and deferiprone (DFP). NADPH oxidase subunit gp91-phox level was analyzed by Western blotting. Our results show that Aβ25-35 induces strong ROS production through NADPH oxidase in Bv2 microglial cells. Intracellular iron depletion resulted in restrained Aβ25-35 induced ROS.
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Affiliation(s)
- Kristin Part
- School of Natural Sciences and Health, Tallinn University, Narva Mnt 29, 10120 Tallinn, Estonia.
| | - Kai Künnis-Beres
- School of Natural Sciences and Health, Tallinn University, Narva Mnt 29, 10120 Tallinn, Estonia; Laboratory of Molecular Genetics National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia.
| | - Helen Poska
- School of Natural Sciences and Health, Tallinn University, Narva Mnt 29, 10120 Tallinn, Estonia.
| | - Tiit Land
- School of Natural Sciences and Health, Tallinn University, Narva Mnt 29, 10120 Tallinn, Estonia.
| | - Ruth Shimmo
- School of Natural Sciences and Health, Tallinn University, Narva Mnt 29, 10120 Tallinn, Estonia.
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18
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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: 250] [Impact Index Per Article: 27.8] [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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19
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Abstract
Highly sophisticated mechanisms that modulate protein structure and function, which involve synthesis and degradation, have evolved to maintain cellular homeostasis. Perturbations in these mechanisms can lead to protein dysfunction as well as deleterious cell processes. Therefore in recent years the etiology of a great number of diseases has been attributed to failures in mechanisms that modulate protein structure. Interconnections among metabolic and cell signaling pathways are critical for homeostasis to converge on mechanisms associated with protein folding as well as for the preservation of the native structure of proteins. For instance, imbalances in secretory protein synthesis pathways lead to a condition known as endoplasmic reticulum (ER) stress which elicits the adaptive unfolded protein response (UPR). Therefore, taking this into consideration, a key part of this paper is developed around the protein folding phenomenon, and cellular mechanisms which support this pivotal condition. We provide an overview of chaperone protein function, UPR via, spatial compartmentalization of protein folding, proteasome role, autophagy, as well as the intertwining between these processes. Several diseases are known to have a molecular etiology in the malfunction of mechanisms responsible for protein folding and in the shielding of native structure, phenomena which ultimately lead to misfolded protein accumulation. This review centers on our current knowledge about pathways that modulate protein folding, and cell responses involved in protein homeostasis.
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20
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Liu CC, Tsai CW, Deak F, Rogers J, Penuliar M, Sung YM, Maher JN, Fu Y, Li X, Xu H, Estus S, Hoe HS, Fryer JD, Kanekiyo T, Bu G. Deficiency in LRP6-mediated Wnt signaling contributes to synaptic abnormalities and amyloid pathology in Alzheimer's disease. Neuron 2014; 84:63-77. [PMID: 25242217 DOI: 10.1016/j.neuron.2014.08.048] [Citation(s) in RCA: 158] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2014] [Indexed: 11/30/2022]
Abstract
Alzheimer's disease (AD) is an age-related neurological disorder characterized by synaptic loss and dementia. The low-density lipoprotein receptor-related protein 6 (LRP6) is an essential coreceptor for Wnt signaling, and its genetic variants have been linked to AD risk. Here we report that neuronal LRP6-mediated Wnt signaling is critical for synaptic function and cognition. Conditional deletion of Lrp6 gene in mouse forebrain neurons leads to age-dependent deficits in synaptic integrity and memory. Neuronal LRP6 deficiency in an amyloid mouse model also leads to exacerbated amyloid pathology due to increased APP processing to amyloid-β. In humans, LRP6 and Wnt signaling are significantly downregulated in AD brains, likely by a mechanism that depends on amyloid-β. Our results define a critical pathway in which decreased LRP6-mediated Wnt signaling, synaptic dysfunction, and elevated Aβ synergistically accelerate AD progression and suggest that restoring LRP6-mediated Wnt signaling can be explored as a viable strategy for AD therapy.
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Affiliation(s)
- Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Chih-Wei Tsai
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Ferenc Deak
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Reynolds Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma HSC, Oklahoma City, OK 73104, USA
| | - Justin Rogers
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Michael Penuliar
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - You Me Sung
- Department of Neuroscience, Georgetown University, Washington, D.C. 20057, USA
| | - James N Maher
- Department of Neuroscience, Georgetown University, Washington, D.C. 20057, USA
| | - Yuan Fu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Xia Li
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Steven Estus
- Department of Physiology and Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40506, USA
| | - Hyang-Sook Hoe
- Department of Neuroscience, Georgetown University, Washington, D.C. 20057, USA; Convergence Brain Research Department, Korea Brain Research Institute (KBRI), 425, Jungang-daero, Jung-gu, Daegu, Korea
| | - John D Fryer
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neurobiology of Disease Graduate Program, Mayo Clinic College of Medicine, Jacksonville, FL 32224, USA
| | - Takahisa Kanekiyo
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA; Neurobiology of Disease Graduate Program, Mayo Clinic College of Medicine, Jacksonville, FL 32224, USA; Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian, China.
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21
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Lopategui Cabezas I, Herrera Batista A, Pentón Rol G. The role of glial cells in Alzheimer disease: potential therapeutic implications. NEUROLOGÍA (ENGLISH EDITION) 2014. [DOI: 10.1016/j.nrleng.2012.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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22
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Liu Q, Zhang J. Lipid metabolism in Alzheimer's disease. Neurosci Bull 2014; 30:331-45. [PMID: 24733655 DOI: 10.1007/s12264-013-1410-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 02/25/2014] [Indexed: 12/14/2022] Open
Abstract
Lipids play crucial roles in cell signaling and various physiological processes, especially in the brain. Impaired lipid metabolism in the brain has been implicated in neurodegenerative diseases, such as Alzheimer's disease (AD), and other central nervous system insults. The brain contains thousands of lipid species, but the complex lipid compositional diversity and the function of each of lipid species are currently poorly understood. This review integrates current knowledge about major lipid changes with the molecular mechanisms that underlie AD pathogenesis.
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Affiliation(s)
- Qiang Liu
- CAS Key Laboratory of Brain Function and Disease and School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China,
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23
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Wunderlich P, Glebov K, Kemmerling N, Tien NT, Neumann H, Walter J. Sequential proteolytic processing of the triggering receptor expressed on myeloid cells-2 (TREM2) protein by ectodomain shedding and γ-secretase-dependent intramembranous cleavage. J Biol Chem 2013; 288:33027-36. [PMID: 24078628 DOI: 10.1074/jbc.m113.517540] [Citation(s) in RCA: 210] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Triggering receptor expressed on myeloid cells-2 (TREM2) and its signaling adaptor protein TYROBP/DAP12 play important roles in signal transduction in dendritic cells, osteoclasts, tissue macrophages, and microglia. Recently, TREM2 variants have been shown to be linked to late onset Alzheimer disease. Here, we demonstrate that TREM2 undergoes sequential proteolytic processing by ectodomain shedding and intramembrane proteolysis. The C-terminal fragment (CTF) of TREM2 generated by ectodomain shedding is cleaved by γ-secretase. Importantly, pharmacologic and genetic γ-secretase inhibition resulted in accumulation of TREM2 CTF at the plasma membrane that also interacts with the signaling adaptor protein DAP12. Thus, the accumulated TREM2 CTF thereby might limit the interaction of DAP12 with the functional full-length receptor, resulting in decreased DAP12 phosphorylation and impaired metabolism of phosphatidylinositol 4,5-bisphosphate. Together, these data demonstrate γ-secretase-mediated intramembranous proteolysis of TREM2 and functionally link two Alzheimer disease-associated proteins in one signaling pathway.
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Affiliation(s)
- Patrick Wunderlich
- From the Department of Neurology, University of Bonn, 53127 Bonn, Germany and
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24
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Lee WH, Loo CY, Bebawy M, Luk F, Mason RS, Rohanizadeh R. Curcumin and its derivatives: their application in neuropharmacology and neuroscience in the 21st century. Curr Neuropharmacol 2013; 11:338-78. [PMID: 24381528 PMCID: PMC3744901 DOI: 10.2174/1570159x11311040002] [Citation(s) in RCA: 296] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 03/17/2013] [Accepted: 03/19/2013] [Indexed: 12/15/2022] Open
Abstract
Curcumin (diferuloylmethane), a polyphenol extracted from the plant Curcuma longa, is widely used in Southeast Asia, China and India in food preparation and for medicinal purposes. Since the second half of the last century, this traditional medicine has attracted the attention of scientists from multiple disciplines to elucidate its pharmacological properties. Of significant interest is curcumin's role to treat neurodegenerative diseases including Alzheimer's disease (AD), and Parkinson's disease (PD) and malignancy. These diseases all share an inflammatory basis, involving increased cellular reactive oxygen species (ROS) accumulation and oxidative damage to lipids, nucleic acids and proteins. The therapeutic benefits of curcumin for these neurodegenerative diseases appear multifactorial via regulation of transcription factors, cytokines and enzymes associated with (Nuclear factor kappa beta) NFκB activity. This review describes the historical use of curcumin in medicine, its chemistry, stability and biological activities, including curcumin's anti-cancer, anti-microbial, anti-oxidant, and anti-inflammatory properties. The review further discusses the pharmacology of curcumin and provides new perspectives on its therapeutic potential and limitations. Especially, the review focuses in detail on the effectiveness of curcumin and its mechanism of actions in treating neurodegenerative diseases such as Alzheimer's and Parkinson's diseases and brain malignancies.
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Affiliation(s)
- Wing-Hin Lee
- Advanced Drug Delivery Group, Faculty of Pharmacy, University of Sydney, NSW 2006, Australia
| | - Ching-Yee Loo
- Advanced Drug Delivery Group, Faculty of Pharmacy, University of Sydney, NSW 2006, Australia
| | - Mary Bebawy
- School of Pharmacy, Graduate School of Health, University of Technology Sydney PO Box 123 Broadway, NSW 2007, Australia
| | - Frederick Luk
- School of Pharmacy, Graduate School of Health, University of Technology Sydney PO Box 123 Broadway, NSW 2007, Australia
| | - Rebecca S Mason
- Physiology and Bosch Institute, University of Sydney, NSW 2006, Australia
| | - Ramin Rohanizadeh
- Advanced Drug Delivery Group, Faculty of Pharmacy, University of Sydney, NSW 2006, Australia
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Amyloid β peptides promote autophagy-dependent differentiation of mouse neural stem cells: Aβ-mediated neural differentiation. Mol Neurobiol 2013; 48:829-40. [PMID: 23729317 DOI: 10.1007/s12035-013-8471-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 05/06/2013] [Indexed: 01/17/2023]
Abstract
Although regarded as neurotoxic, amyloid β (Aβ) peptides may also mediate a wide range of nonpathogenic processes. Autophagy has been implicated in Aβ-mediated effects, although its precise function in neural differentiation remains unknown. Here, we addressed the role of different Aβ fragments in neural stem cell (NSC) proliferation and differentiation, and investigated whether autophagy is involved in Aβ-induced alterations of neural fate. Our results demonstrate that neuronal and glial-specific protein markers are significantly induced by both Aβ1-40 and Aβ1-42. However, Aβ1-40 preferentially enhances neurogenesis of NSCs, as determined by βIII-tubulin, NeuN, and MAP2 neuronal marker immunoreactivity, while Aβ1-42 appears to favor gliogenesis. In contrast, Aβ25-35 does not influence NSC fate. The effect of Aβ1-40 on neurogenesis is partially dependent on its role in NSC self-renewal as both S-phase of the cell cycle and BrdU labeling were markedly increased. Nevertheless, Aβ1-40 resulted also in increased Tuj1 promoter activity. Autophagy, assessed by conversion of endogenous LC3-I/II, fluorescence of pGFP-LC3-transfected cells, and Atg9 protein levels, was evident in both Aβ1-40- and Aβ1-42-treated NSCs, independently of reactive oxygen species production and apoptosis. Finally, inhibition of autophagy by pharmacologic means abrogated Aβ-induced lineage-specific protein markers. These results support distinct roles for different Aβ peptides in NSC fate decision and underline the importance of autophagy control of this process.
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Aly KA, Beebe ET, Chan CH, Goren MA, Sepúlveda C, Makino SI, Fox BG, Forest KT. Cell-free production of integral membrane aspartic acid proteases reveals zinc-dependent methyltransferase activity of the Pseudomonas aeruginosa prepilin peptidase PilD. Microbiologyopen 2012; 2:94-104. [PMID: 23255525 PMCID: PMC3584216 DOI: 10.1002/mbo3.51] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 10/30/2012] [Accepted: 11/05/2012] [Indexed: 12/25/2022] Open
Abstract
Integral membrane aspartic acid proteases are receiving growing recognition for their fundamental roles in cellular physiology of eukaryotes and prokaryotes, and may be medically important pharmaceutical targets. The Gram-negative Pseudomonas aeruginosa PilD and the archaeal Methanococcus voltae FlaK were synthesized in the presence of unilamellar liposomes in a cell-free translation system. Cosynthesis of PilD with its full-length substrate, PilA, or of FlaK with its full-length substrate, FlaB2, led to complete cleavage of the substrate signal peptides. Scaled-up synthesis of PilD, followed by solubilization in dodecyl-β-d-maltoside and chromatography, led to a pure enzyme that retained both of its known biochemical activities: cleavage of the PilA signal peptide and S-adenosyl methionine-dependent methylation of the mature pilin. X-ray fluorescence scans show for the first time that PilD is a zinc-binding protein. Zinc is required for the N-terminal methylation of the mature pilin, but not for signal peptide cleavage. Taken together, our work identifies the P. aeruginosa prepilin peptidase PilD as a zinc-dependent N-methyltransferase and provides a new platform for large-scale synthesis of PilD and other integral membrane proteases important for basic microbial physiology and virulence.
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Affiliation(s)
- Khaled A Aly
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
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27
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The role of glial cells in Alzheimer disease: potential therapeutic implications. Neurologia 2012; 29:305-9. [PMID: 23246214 DOI: 10.1016/j.nrl.2012.10.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 10/04/2012] [Indexed: 01/13/2023] Open
Abstract
INTRODUCTION Alzheimer (AD) disease is a complex neurodegenerative disease characterised by inflammation, neurotoxicity, oxidative stress, and reactive gliosis. Microglia and astrocytes not only act as antigen-presenting cells, but also function as effector cells releasing pro-inflammatory molecules that promote excitotoxicity and neurodegeneration. OBJECTIVE In the present review we discuss the role of glia, specifically microglia and astrocytes, in the pathophysiology of AD and possible therapeutic implications. DEVELOPMENT The growing body of evidence suggesting that microglia and astrocytes play a pathogenic role and activate inflammation pathways, the neurotoxic factors released by these cells when activated, and the way these factors may disrupt the homeostasis of the central nervous system all support the hypothesis that glia-induced inflammation exacerbates AD. CONCLUSIONS Inhibiting inflammation by deactivating glial cells may reduce the production of factors which contribute to neurotoxicity, and therefore result in clinical improvement. Microglia and astrocytes are therapeutic targets for the development of new drugs to combat this disease. Therapeutic strategies designed to counter the detrimental effects of overactivation of these cell populations should be investigated.
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Inhibition of IL-12/IL-23 signaling reduces Alzheimer's disease-like pathology and cognitive decline. Nat Med 2012. [PMID: 23178247 DOI: 10.1038/nm.2965] [Citation(s) in RCA: 292] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The pathology of Alzheimer's disease has an inflammatory component that is characterized by upregulation of proinflammatory cytokines, particularly in response to amyloid-β (Aβ). Using the APPPS1 Alzheimer's disease mouse model, we found increased production of the common interleukin-12 (IL-12) and IL-23 subunit p40 by microglia. Genetic ablation of the IL-12/IL-23 signaling molecules p40, p35 or p19, in which deficiency of p40 or its receptor complex had the strongest effect, resulted in decreased cerebral amyloid load. Although deletion of IL-12/IL-23 signaling from the radiation-resistant glial compartment of the brain was most efficient in mitigating cerebral amyloidosis, peripheral administration of a neutralizing p40-specific antibody likewise resulted in a reduction of cerebral amyloid load in APPPS1 mice. Furthermore, intracerebroventricular delivery of antibodies to p40 significantly reduced the concentration of soluble Aβ species and reversed cognitive deficits in aged APPPS1 mice. The concentration of p40 was also increased in the cerebrospinal fluid of subjects with Alzheimer's disease, which suggests that inhibition of the IL-12/IL-23 pathway may attenuate Alzheimer's disease pathology and cognitive deficits.
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Identification and characterization of five intramembrane metalloproteases in Anabaena variabilis. J Bacteriol 2012; 194:6105-15. [PMID: 22961855 DOI: 10.1128/jb.01366-12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Regulated intramembrane proteolysis (RIP) involves cleavage of a transmembrane segment of a protein, releasing the active form of a membrane-anchored transcription factor (MTF) or a membrane-tethered signaling protein in response to an extracellular or intracellular signal. RIP is conserved from bacteria to humans and governs many important signaling pathways in both prokaryotes and eukaryotes. Proteases that carry out these cleavages are named intramembrane cleaving proteases (I-CLips). To date, little is known about I-CLips in cyanobacteria. In this study, five putative site-2 type I-Clips (Ava_1070, Ava_1730, Ava_1797, Ava_3438, and Ava_4785) were identified through a genome-wide survey in Anabaena variabilis. Biochemical analysis demonstrated that these five putative A. variabilis site-2 proteases (S2Ps(Av)) have authentic protease activities toward an artificial substrate pro-σ(K), a Bacillus subtilis MTF, in our reconstituted Escherichia coli system. The enzymatic activities of processing pro-σ(K) differ among these five S2Ps(Av). Substitution of glutamic acid (E) by glutamine (Q) in the conserved HEXXH zinc-coordinated motif caused the loss of protease activities in these five S2Ps(Av), suggesting that they belonged to the metalloprotease family. Further mapping of the cleaved peptides of pro-σ(K) by Ava_4785 and Ava_1797 revealed that Ava_4785 and Ava_1797 recognized the same cleavage site in pro-σ(K) as SpoIVFB, a cognate S2P of pro-σ(K) from B. subtilis. Taking these results together, we report here for the first time the identification of five metallo-intramembrane cleaving proteases in Anabaena variabilis. The experimental system described herein should be applicable to studies of other RIP events and amenable to developing in vitro assays for I-CLips.
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Neill D. Should Alzheimer's disease be equated with human brain ageing? A maladaptive interaction between brain evolution and senescence. Ageing Res Rev 2012; 11:104-22. [PMID: 21763787 DOI: 10.1016/j.arr.2011.06.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 06/26/2011] [Accepted: 06/28/2011] [Indexed: 10/18/2022]
Abstract
In this review Alzheimer's disease is seen as a maladaptive interaction between human brain evolution and senescence. It is predicted to occur in everyone although does not necessarily lead to dementia. The pathological process is initiated in relation to a senescence mediated functional down-regulation in the posteromedial cortex (Initiation Phase). This leads to a loss of glutamatergic excitatory input to layer II entorhinal cortex neurons. A human specific maladaptive neuroplastic response is initiated in these neurons leading to neuronal dysfunction, NFT formation and death. This leads to further loss of glutamatergic excitatory input and propagation of the maladaptive response along excitatory pathways linking evolutionary progressed vulnerable neurons (Propagation Phase). Eventually neurons are affected in many brain areas resulting in dementia. Possible therapeutic approaches include enhancing glutamatergic transmission. The theory may have implications with regards to how Alzheimer's disease is classified.
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A nuclear variant of ErbB3 receptor tyrosine kinase regulates ezrin distribution and Schwann cell myelination. J Neurosci 2011; 31:5106-19. [PMID: 21451047 DOI: 10.1523/jneurosci.5635-10.2011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Reciprocal interactions between glia and neurons are essential for the proper organization and function of the nervous system. Recently, the interaction between ErbB receptors (ErbB2 and ErbB3) on the surface of Schwann cells and neuronal Neuregulin-1 (NRG1) has emerged as the pivotal signal that controls Schwann cell development, association with axons, and myelination. To understand the function of NRG1-ErbB2/3 signaling axis in adult Schwann cell biology, we are studying the specific role of ErbB3 receptor tyrosine kinase (RTK) since it is the receptor for NRG1 on the surface of Schwann cells. Here, we show that alternative transcription initiation results in the formation of a nuclear variant of ErbB3 (nuc-ErbB3) in rat primary Schwann cells. nuc-ErbB3 possesses a functional nuclear localization signal sequence and binds to chromatin. Using chromatin immunoprecipitation (ChIP)-chip arrays, we identified the promoters that associate with nuc-ErbB3 and clustered the active promoters in Schwann cell gene expression. nuc-ErbB3 regulates the transcriptional activity of ezrin and HMGB1 promoters, whereas inhibition of nuc-ErbB3 expression results in reduced myelination and altered distribution of ezrin in the nodes of Ranvier. Finally, we reveal that NRG1 regulates the translation of nuc-ErbB3 in rat Schwann cells. For the first time, to our knowledge, we show that alternative transcription initiation from a gene that encodes a RTK is capable to generate a protein variant of the receptor with a distinct role in molecular and cellular regulation. We propose a new concept for the molecular regulation of myelination through the expression and distinct role of nuc-ErbB3.
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Bordji K, Becerril-Ortega J, Buisson A. Synapses, NMDA receptor activity and neuronal Aβ production in Alzheimer's disease. Rev Neurosci 2011; 22:285-94. [PMID: 21568789 DOI: 10.1515/rns.2011.029] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A direct relationship has been established between synaptic activity and amyloid-β secretion. Dysregulation of neuronal calcium homeostasis was shown to increase production of amyloid-β, contributing to the initiation of Alzheimer's disease. Among the different routes of Ca(2+) entry, N-methyl-d-aspartate (NMDA) receptors, a subtype of ionotropic glutamate receptors, are especially involved in this process because of their ability to gate high levels of Ca(2+) influx. These receptors have been extensively studied for their crucial roles in synaptic plasticity that underlies learning and memory but also in neurotoxicity occurring during acute brain injuries and neurodegenerative diseases. For one decade, several studies provided evidence that NMDA receptor activation could have distinct consequences on neuronal fate, depending on their location. Synaptic NMDA receptor activation is neuroprotective, whereas extrasynaptic NMDA receptors trigger neuronal death and/or neurodegenerative processes. Recent data suggest that chronic activation of extrasynaptic NMDA receptors leads to a sustained neuronal amyloid-β release and could be involved in the pathogenesis of Alzheimer's disease. Thus, as for other neurological diseases, therapeutic targeting of extrasynaptic NMDA receptors could be a promising strategy. Following this concept, memantine, unlike other NMDA receptor antagonists was shown, to preferentially target the extrasynaptic NMDA receptor signaling pathways, while relatively sparing normal synaptic activity. This molecular mechanism could therefore explain why memantine is, to date, the only clinically approved NMDA receptor antagonist for the treatment of dementia.
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Affiliation(s)
- Karim Bordji
- Groupement d'Intérêt Public Cyceron, Centre National de la Recherche Scientifique, UMR 6232-Centre d'Imagerie Neurosciences et d'Applications aux Pathologies, Bd Becquerel, F-14074 Caen, France.
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33
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Schieb H, Weidlich S, Schlechtingen G, Linning P, Jennings G, Gruner M, Wiltfang J, Klafki HW, Knölker HJ. Structural design, solid-phase synthesis and activity of membrane-anchored β-secretase inhibitors on Aβ generation from wild-type and Swedish-mutant APP. Chemistry 2011; 16:14412-23. [PMID: 21132705 DOI: 10.1002/chem.201002878] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Covalent coupling of β-secretase inhibitors to a raftophilic lipid anchor via a suitable spacer by using solid-phase peptide synthesis leads to tripartite structures displaying substantially improved inhibition of cellular secretion of the β-amyloid peptide (Aβ). Herein, we describe a series of novel tripartite structures, their full characterization by NMR spectroscopy and mass spectrometry, and the analysis of their biological activity in cell-based assays. The tripartite structure concept is applicable to different pharmacophores, and the potency in terms of β-secretase inhibition can be optimized by adjusting the spacer length to achieve an optimal distance of the inhibitor from the lipid bilayer. A tripartite structure containing a transition-state mimic inhibitor was found to be less potent on Aβ generation from Swedish-mutant amyloid precursor protein (APP) than from the wild-type protein. Moreover, our observations suggest that specific variants of Aβ are generated from wild-type APP but not from Swedish-mutant APP and are resistant to β-secretase inhibition. Efficient inhibition of Aβ secretion by tripartite structures in the absence of appreciable neurotoxicity was confirmed in a primary neuronal cell culture, thus further supporting the concept.
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Affiliation(s)
- Heinke Schieb
- Department of Psychiatry and Psychotherapy, University of Duisburg-Essen, LVR-Klinikum, Essen, Germany
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34
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Singh TD, Park SY, Bae JS, Yun Y, Bae YC, Park RW, Kim IS. MEGF10 functions as a receptor for the uptake of amyloid-β. FEBS Lett 2010; 584:3936-42. [DOI: 10.1016/j.febslet.2010.08.050] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 07/31/2010] [Accepted: 08/30/2010] [Indexed: 10/19/2022]
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35
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Seki M, Watanabe A, Enomoto S, Kawamura T, Ito H, Kodama T, Hamakubo T, Aburatani H. Human ROBO1 is cleaved by metalloproteinases and gamma-secretase and migrates to the nucleus in cancer cells. FEBS Lett 2010; 584:2909-15. [PMID: 20471383 DOI: 10.1016/j.febslet.2010.05.009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Accepted: 05/05/2010] [Indexed: 01/10/2023]
Abstract
ROBO1 is a receptor mediating Slit-induced repulsive action on axon guidance and differentially expressed in human cancers. Although ROBO1 ectodomain has been detected, the cleavage site had not been determined. In this study we identified the precise cleavage site of ROBO1. We also report multi-step proteolysis of ROBO1 by metalloproteinases and gamma-secretase, producing two carboxy-terminal fragments, ROBO1-CTF1 at 129-kDa and ROBO1-CTF2 at 118-kDa. We have further demonstrated nuclear accumulation of ROBO1, which is abolished by either a metalloproteinase inhibitor TAPI-1 or a gamma-secretase inhibitor L-685,458. ROBO1 may function beyond the receptor through stepwise cleavages and translocation to the nucleus.
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Affiliation(s)
- Motoaki Seki
- Genome Science Division, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
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36
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Sahara N, Lewis J. Amyloid precursor protein and tau transgenic models of Alzheimer's disease: insights from the past and directions for the future. FUTURE NEUROLOGY 2010; 5:411-420. [PMID: 20730022 DOI: 10.2217/fnl.10.10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
During the last 20 years, our understanding of the mechanisms underlying Alzheimer's disease (AD) has considerably improved, in part owing to both in vitro and in vivo model systems. Studies in mice expressing both human amyloid precursor protein and human tau have provided clear evidence that amyloid-beta and tau interact in the pathogenesis of AD. Moreover, amyloid-beta toxicity has been shown to be tau-dependent since reducing tau levels prevents behavioral deficits and sudden death in amyloid precursor protein transgenic mice. As tau pathology preferentially develops in specific sites and spreads in a predictable manner across the brain, understanding the mechanism underlying tau dysfunction should be a focus in AD mouse modeling. A defined effort must be made to develop therapies that directly address the impact of tau dysfunction in the pathogenesis of AD. Finally, early diagnosis of AD is essential and this must be made possible by identification of early biomarkers, behavioral changes or use of novel imaging techniques.
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Affiliation(s)
- Naruhiko Sahara
- Department of Neuroscience, Mayo Clinic, Jacksonville FL 32224, USA
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37
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Soluble amyloid-beta, effect on cerebral arteriolar regulation and vascular cells. Mol Neurodegener 2010; 5:15. [PMID: 20388225 PMCID: PMC2873254 DOI: 10.1186/1750-1326-5-15] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Accepted: 04/13/2010] [Indexed: 12/22/2022] Open
Abstract
Background Evidence indicates that soluble forms of amyloid-β (Aβ) are vasoactive, which may contribute to cerebrovascular dysfunction noted in patients with Alzheimer's Disease and cerebral amyloid angiopathy. The effects of soluble Aβ on penetrating cerebral arterioles - the vessels most responsible for controlling cerebrovascular resistance - have not been studied. Results Freshly dissolved Aβ1-40 and Aβ1-42, but not the reverse peptide Aβ40-1 constricted isolated rat penetrating arterioles and diminished dilation to adenosine tri-phosphate (ATP). Aβ1-42 also enhanced ATP-induced vessel constriction. Aβ1-40 diminished arteriolar myogenic response, and an anti-Aβ antibody reduced Aβ1-40 induced arteriolar constriction. Prolonged Aβ exposure in vessels of Tg2576 mice resulted in a marked age-dependent effect on ATP-induced vascular responses. Vessels from 6 month old Tg2576 mice had reduced vascular responses whereas these were absent from 12 month old animals. Aβ1-40 and Aβ1-42 acutely increased production of reactive oxygen species (ROS) in cultured rat cerebro-microvascular cells. The radical scavenger MnTBAP attenuated this Aβ-induced oxidative stress and Aβ1-40-induced constriction in rat arterioles. Conclusions Our results suggest that soluble Aβ1-40 and Aβ1-42 directly affect the vasomotor regulation of isolated rodent penetrating arterioles, and that ROS partially mediate these effects. Once insoluble Aβ deposits are present, arteriolar reactivity is greatly diminished.
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38
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Kim J, Castellano JM, Jiang H, Basak JM, Parsadanian M, Pham V, Mason SM, Paul SM, Holtzman DM. Overexpression of low-density lipoprotein receptor in the brain markedly inhibits amyloid deposition and increases extracellular A beta clearance. Neuron 2010; 64:632-44. [PMID: 20005821 DOI: 10.1016/j.neuron.2009.11.013] [Citation(s) in RCA: 193] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/02/2009] [Indexed: 11/30/2022]
Abstract
Apolipoprotein E (APOE) is the strongest genetic risk factor for Alzheimer's disease (AD). Previous studies suggest that the effect of apoE on amyloid-beta (A beta) accumulation plays a major role in AD pathogenesis. Therefore, understanding proteins that control apoE metabolism may provide new targets for regulating A beta levels. LDLR, a member of the LDL receptor family, binds to apoE, yet its potential role in AD pathogenesis remains unclear. We hypothesized that LDLR overexpression in the brain would decrease apoE levels, enhance A beta clearance, and decrease A beta deposition. To test our hypothesis, we created several transgenic mice that overexpress LDLR in the brain and found that apoE levels in these mice decreased by 50%-90%. Furthermore, LDLR overexpression dramatically reduced A beta aggregation and enhanced A beta clearance from the brain extracellular space. Plaque-associated neuroinflammatory responses were attenuated in LDLR transgenic mice. These findings suggest that increasing LDLR levels may represent a novel AD treatment strategy.
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Affiliation(s)
- Jungsu Kim
- Department of Neurology, Developmental Biology, Hope Center for Neurological Disorders, Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
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39
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Abstract
More than two decades ago, dysregulation of the intracellular Ca2+ homeostasis was suggested to underlie the development of Alzheimer’s disease (AD). This hypothesis was tested in numerous in vitro studies, which revealed multiple Ca2+ signalling pathways able to contribute to AD pathology. It remained, however, unclear whether these pathways are also activated in vivo, in cells involved in signal processing in the living brain. Here we review recent data analysing intracellular Ca2+ signalling in vivo in the context of previous in vitro findings. We particularly focus on the processes taking place in the immediate vicinity of amyloid plaques and on their possible role for AD-mediated brain dysfunction.
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Affiliation(s)
- Marina Hermes
- University of Tübingen, Institute of Physiology II, Tübingen, Germany
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40
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Fleming MR, Kaczmarek LK. Use of optical biosensors to detect modulation of Slack potassium channels by G protein-coupled receptors. J Recept Signal Transduct Res 2009; 29:173-81. [PMID: 19640220 DOI: 10.1080/10799890903056883] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Ion channels control the electrical properties of neurons and other excitable cell types by selectively allowing ion to flow through the plasma membrane. To regulate neuronal excitability, the biophysical properties of ion channels are modified by signaling proteins and molecules, which often bind to the channels themselves to form a heteromeric channel complex. Traditional assays examining the interaction between channels and regulatory proteins generally provide little information on the time-course of interactions in living cells. We have now used a novel label-free technology to detect changes in the distribution of mass close to the plasma membrane following modulation of potassium channels by G protein-coupled receptors (GPCRs). This technology uses optical sensors embedded in microplates to detect changes in the refractive index at the surface of cells. Although the activation of GPCRs has been studied with this system, protein-protein interactions due to modulation of ion channels have not yet been characterized. Here we present data that the characteristic pattern of mass distribution following GPCR activation is significantly modified by the presence of a sodium-activated potassium channel, Slack-B, a channel that is known to be potently modulated by activation of these receptors.
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Affiliation(s)
- Matthew R Fleming
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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Kim J, Basak JM, Holtzman DM. The role of apolipoprotein E in Alzheimer's disease. Neuron 2009; 63:287-303. [PMID: 19679070 PMCID: PMC3044446 DOI: 10.1016/j.neuron.2009.06.026] [Citation(s) in RCA: 1070] [Impact Index Per Article: 71.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2009] [Revised: 06/22/2009] [Accepted: 06/25/2009] [Indexed: 01/17/2023]
Abstract
The epsilon4 allele of apolipoprotein E (APOE) is the major genetic risk factor for Alzheimer's disease (AD). Although there have been numerous studies attempting to elucidate the underlying mechanism for this increased risk, how apoE4 influences AD onset and progression has yet to be proven. However, prevailing evidence suggests that the differential effects of apoE isoforms on Abeta aggregation and clearance play the major role in AD pathogenesis. Other potential mechanisms, such as the differential modulation of neurotoxicity and tau phosphorylation by apoE isoforms as well as its role in synaptic plasticity and neuroinflammation, have not been ruled out. Inconsistent results among studies have made it difficult to define whether the APOE epsilon4 allele represents a gain of toxic function, a loss of neuroprotective function, or both. Therapeutic strategies based on apoE propose to reduce the toxic effects of apoE4 or to restore the physiological, protective functions of apoE.
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Affiliation(s)
- Jungsu Kim
- Department of Neurology, Developmental Biology, Hope Center for Neurological Disorders, Alzheimer's Disease Research Center, Washington University School of Medicine, St. Louis, MO 63110, USA
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Jakob-Roetne R, Jacobsen H. Alzheimer's disease: from pathology to therapeutic approaches. Angew Chem Int Ed Engl 2009; 48:3030-59. [PMID: 19330877 DOI: 10.1002/anie.200802808] [Citation(s) in RCA: 486] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Mind how you go: The current strategies for the development of therapies for Alzheimer's disease are very diverse. Particular attention is given to the search for inhibitors (see picture for two examples) of the proteolytic enzyme beta- and gamma-secretase, which inhibits the cleavage of the amyloid precursor proteins into amyloid beta peptides, from which the disease-defining deposits of plaque in the brains of Alzheimer's patients originates.Research on senile dementia and Alzheimer's disease covers an extremely broad range of scientific activities. At the recent international meeting of the Alzheimer's Association (ICAD 2008, Chicago) more than 2200 individual scientific contributions were presented. The aim of this Review is to give an overview of the field and to outline its main areas, starting from behavioral abnormalities and visible pathological findings and then focusing on the molecular details of the pathology. The "amyloid hypothesis" of Alzheimer's disease is given particular attention, since the majority of the ongoing therapeutic approaches are based on its theoretical framework.
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Affiliation(s)
- Roland Jakob-Roetne
- F.Hoffmann-La Roche AG, Medicinal Chemistry, Bldg 92/8.10B, 4070 Basel, Switzerland.
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Jakob-Roetne R, Jacobsen H. Die Alzheimer-Demenz: von der Pathologie zu therapeutischen Ansätzen. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200802808] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Bojarski L, Pomorski P, Szybinska A, Drab M, Skibinska-Kijek A, Gruszczynska-Biegala J, Kuznicki J. Presenilin-dependent expression of STIM proteins and dysregulation of capacitative Ca2+ entry in familial Alzheimer's disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1793:1050-7. [PMID: 19111578 DOI: 10.1016/j.bbamcr.2008.11.008] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 11/07/2008] [Accepted: 11/21/2008] [Indexed: 10/21/2022]
Abstract
Mutations in presenilin 1 (PS1), which are the major cause of familial Alzheimer's disease (FAD), are involved in perturbations of cellular Ca2+ homeostasis. Attenuation of capacitative Ca2+ entry (CCE) is the most often observed alteration of Ca2+ homeostasis in cells bearing FAD PS1 mutations. However, molecular mechanisms underlying this CCE impairment remains elusive. We demonstrate that cellular levels of STIM1 and STIM2 proteins, which are key players in CCE, depend on presenilins. We found increased level of STIM1 and decreased level of STIM2 proteins in mouse embryonic fibroblasts lacking presenilins. Fura-2 ratiometric assays revealed that CCE is enhanced in these cells after Ca2+ stores depletion by thapsigargin treatment. In turn, overexpression of PS1 with FAD mutations in HEK293 cells led to an attenuation of CCE. Although, no changes in STIM protein levels were observed in these HEK293 cells, FAD mutations in endogenous PS1 in human B lymphocytes resulted in a decreased expression of STIM2 in parallel to an attenuation of CCE. Our experiments showing that knock-out of presenilins in MEF cells and FAD mutations in endogenous PS1 in lymphocytes affect both CCE and the cellular level of STIM proteins open new perspectives for studies on CCE in FAD.
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Affiliation(s)
- Lukasz Bojarski
- Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology, 4 Ks. Trojdena Street, 02-109 Warsaw, Poland
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Zeng N, Liu L, McCabe MG, Jones DTW, Ichimura K, Collins VP. Real-time quantitative polymerase chain reaction (qPCR) analysis with fluorescence resonance energy transfer (FRET) probes reveals differential expression of the four ERBB4 juxtamembrane region variants between medulloblastoma and pilocytic astrocytoma. Neuropathol Appl Neurobiol 2008; 35:353-366. [PMID: 19017278 DOI: 10.1111/j.1365-2990.2008.01001.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
AIMS We report a comparative study on the mRNA expression of ErbB receptor tyrosine kinases, and in particular ERBB4 transcript variants, in two common paediatric brain tumours: medulloblastoma (MB) and pilocytic astrocytoma (PA). METHODS While the conventional real-time quantitative polymerase chain reaction was used to measure the expression of ERRBs and ErbB4-processing protease genes, the LightCycler fluorescence resonance energy transfer probes were specifically designed to investigate all of the known ERBB4 juxtamembrane (JM) and cytoplasmic transcript variants. RESULTS The overall expression of ERBBs suggests that ErbB2/ErbB4 heterodimers and ErbB4 homodimers may be major functional units of the ErbBs in MB, while ErbB2/ErbB3 heterodimers may play a more prominent role in addition to ErbB4-containing dimers in PA. Different expression patterns of ERBB4 JM transcripts in MB, PA and normal brain were observed. The JM-d variant was only detected in MBs, while JM-c was present in MB and PA but was not identified in normal brain. The expression of cleavable ERBB4 transcript variants was elevated in PAs and MBs compared with normal brain, while mRNA levels of ErbB4-processing proteases were similar in both tumour types and normal brain. This suggests that proteolytic cleavage of ErbB4 may be more common in MB and PA, which leads to signalling events divergent from those in normal brain. CONCLUSION Taken together, these results suggest that ErbB4 processing and function may be altered in brain tumours, such as MB and PA, via differential expression of JM transcript variants.
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Affiliation(s)
- N Zeng
- Department of Pathology, Division of Molecular Histopathology, University of Cambridge, Cambridge, UK
| | - L Liu
- Department of Pathology, Division of Molecular Histopathology, University of Cambridge, Cambridge, UK
| | - M G McCabe
- Department of Pathology, Division of Molecular Histopathology, University of Cambridge, Cambridge, UK
| | - D T W Jones
- Department of Pathology, Division of Molecular Histopathology, University of Cambridge, Cambridge, UK
| | - K Ichimura
- Department of Pathology, Division of Molecular Histopathology, University of Cambridge, Cambridge, UK
| | - V P Collins
- Department of Pathology, Division of Molecular Histopathology, University of Cambridge, Cambridge, UK
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Chen X, Ulintz PJ, Simon ES, Williams JA, Andrews PC. Global topology analysis of pancreatic zymogen granule membrane proteins. Mol Cell Proteomics 2008; 7:2323-36. [PMID: 18682380 DOI: 10.1074/mcp.m700575-mcp200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The zymogen granule is the specialized organelle in pancreatic acinar cells for digestive enzyme storage and regulated secretion and is a classic model for studying secretory granule function. Our long term goal is to develop a comprehensive architectural model for zymogen granule membrane (ZGM) proteins that would direct new hypotheses for subsequent functional studies. Our initial proteomics analysis focused on identification of proteins from purified ZGM (Chen, X., Walker, A. K., Strahler, J. R., Simon, E. S., Tomanicek-Volk, S. L., Nelson, B. B., Hurley, M. C., Ernst, S. A., Williams, J. A., and Andrews, P. C. (2006) Organellar proteomics: analysis of pancreatic zymogen granule membranes. Mol. Cell. Proteomics 5, 306-312). In the current study, a new global topology analysis of ZGM proteins is described that applies isotope enrichment methods to a protease protection protocol. Our results showed that tryptic peptides of ZGM proteins were separated into two distinct clusters according to their isobaric tag for relative and absolute quantification (iTRAQ) ratios for proteinase K-treated versus control zymogen granules. The low iTRAQ ratio cluster included cytoplasm-orientated membrane and membrane-associated proteins including myosin V, vesicle-associated membrane proteins, syntaxins, and all the Rab proteins. The second cluster having unchanged ratios included predominantly luminal proteins. Because quantification is at the peptide level, this technique is also capable of mapping both cytoplasm- and lumen-orientated domains from the same transmembrane protein. To more accurately assign the topology, we developed a statistical mixture model to provide probabilities for identified peptides to be cytoplasmic or luminal based on their iTRAQ ratios. By implementing this approach to global topology analysis of ZGM proteins, we report here an experimentally constrained, comprehensive topology model of identified zymogen granule membrane proteins. This model contributes to a firm foundation for developing a higher order architecture model of the ZGM and for future functional studies of individual ZGM proteins.
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Affiliation(s)
- Xuequn Chen
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.
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Liang WS, Dunckley T, Beach TG, Grover A, Mastroeni D, Ramsey K, Caselli RJ, Kukull WA, McKeel D, Morris JC, Hulette CM, Schmechel D, Reiman EM, Rogers J, Stephan DA. Altered neuronal gene expression in brain regions differentially affected by Alzheimer's disease: a reference data set. Physiol Genomics 2008; 33:240-56. [PMID: 18270320 DOI: 10.1152/physiolgenomics.00242.2007] [Citation(s) in RCA: 225] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's Disease (AD) is the most widespread form of dementia during the later stages of life. If improved therapeutics are not developed, the prevalence of AD will drastically increase in the coming years as the world's population ages. By identifying differences in neuronal gene expression profiles between healthy elderly persons and individuals diagnosed with AD, we may be able to better understand the molecular mechanisms that drive AD pathogenesis, including the formation of amyloid plaques and neurofibrillary tangles. In this study, we expression profiled histopathologically normal cortical neurons collected with laser capture microdissection (LCM) from six anatomically and functionally discrete postmortem brain regions in 34 AD-afflicted individuals, using Affymetrix Human Genome U133 Plus 2.0 microarrays. These regions include the entorhinal cortex, hippocampus, middle temporal gyrus, posterior cingulate cortex, superior frontal gyrus, and primary visual cortex. This study is predicated on previous parallel research on the postmortem brains of the same six regions in 14 healthy elderly individuals, for which LCM neurons were similarly processed for expression analysis. We identified significant regional differential expression in AD brains compared with control brains including expression changes of genes previously implicated in AD pathogenesis, particularly with regard to tangle and plaque formation. Pinpointing the expression of factors that may play a role in AD pathogenesis provides a foundation for future identification of new targets for improved AD therapeutics. We provide this carefully phenotyped, laser capture microdissected intraindividual brain region expression data set to the community as a public resource.
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Affiliation(s)
- Winnie S Liang
- Neurogenomics Division, Translational Genomics Research Institute, Phoenix, Arizona 85004, USA
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Zhao B, Yu M, Neitzel M, Marugg J, Jagodzinski J, Lee M, Hu K, Schenk D, Yednock T, Basi G. Identification of γ-Secretase Inhibitor Potency Determinants on Presenilin. J Biol Chem 2008; 283:2927-38. [DOI: 10.1074/jbc.m708870200] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Bojarski L, Herms J, Kuznicki J. Calcium dysregulation in Alzheimer's disease. Neurochem Int 2007; 52:621-33. [PMID: 18035450 DOI: 10.1016/j.neuint.2007.10.002] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Revised: 09/12/2007] [Accepted: 10/01/2007] [Indexed: 12/21/2022]
Abstract
Alzheimer disease (AD) is the most common form of adult dementia. Its pathological hallmarks are synaptic degeneration, deposition of amyloid plaques and neurofibrillary tangles, leading to neuronal loss. A few hypotheses have been proposed to explain AD pathogenesis. The beta-amyloid (Abeta) and hyperphosphorylated tau hypotheses suggest that these proteins are the main players in AD development. Another hypothesis proposes that the dysregulation of calcium homeostasis may be a key factor in accelerating other pathological changes. Although Abeta and tau have been extensively studied, recently published data provide a growing body of evidence supporting the critical role of calcium signalling in AD. For example, presenilins, which are mutated in familial cases of AD, were demonstrated to form low conductance calcium channels in the ER and elevated cytosolic calcium concentration increases amyloid generation. Moreover, memantine, an antagonist of the NMDA-calcium channel receptor, has been found to have a beneficial effect for AD patients offering novel possibilities for a calcium signalling targeted therapy of AD. This review underscores the growing importance of calcium ions in AD development and focuses on the relevant aspects of calcium homeostasis.
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Affiliation(s)
- Lukasz Bojarski
- International Institute of Molecular and Cell Biology, 4 Ks. Trojdena Street, 02-109 Warsaw, Poland
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Prager K, Wang-Eckhardt L, Fluhrer R, Killick R, Barth E, Hampel H, Haass C, Walter J. A Structural Switch of Presenilin 1 by Glycogen Synthase Kinase 3β-mediated Phosphorylation Regulates the Interaction with β-Catenin and Its Nuclear Signaling. J Biol Chem 2007; 282:14083-93. [PMID: 17360711 DOI: 10.1074/jbc.m608437200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Presenilins (PS) are critical components of the gamma-secretase complex that mediates cleavage of type I membrane proteins including the beta-amyloid precursor protein to generate the amyloid beta-peptide. In addition, PS1 interacts with beta-catenin and facilitates its metabolism. We demonstrate that phosphorylation of serines 353 and 357 by glycogen synthase kinase-3beta (GSK3beta) induces a structural change of the hydrophilic loop of PS1 that can also be mimicked by substitution of the phosphorylation sites by negatively charged amino acids in vitro and in cultured cells. The structural change of PS1 reduces the interaction with beta-catenin leading to decreased phosphorylation and ubiquitination of beta-catenin. The decreased interaction of PS1 with beta-catenin leads to stabilization of beta-catenin thereby increasing its nuclear signaling and the transcription of target genes, including c-MYC. Consistent with increased expression of c-myc, a PS1 mutant that mimics phosphorylated PS1 increased cell proliferation as compared with wild-type PS1. These results indicate a regulatory mechanism in which GSK3beta-mediated phosphorylation induces a structural change of the hydrophilic loop of PS1 thereby negatively modulating the formation of a ternary complex between beta-catenin, PS1, and GSK3beta, which leads to stabilization of beta-catenin.
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Affiliation(s)
- Kai Prager
- Department of Neurology, University of Bonn, Bonn, Germany
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