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Velezmoro Jauregui G, Vukić D, Onyango IG, Arias C, Novotný JS, Texlová K, Wang S, Kovačovicova KL, Polakova N, Zelinkova J, Čarna M, Lacovich V, Head BP, Havas D, Mistrik M, Zorec R, Verkhratsky A, Keegan L, O'Connell MA, Rissman R, Stokin GB. Amyloid precursor protein induces reactive astrogliosis. Acta Physiol (Oxf) 2024; 240:e14142. [PMID: 38584589 DOI: 10.1111/apha.14142] [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: 02/25/2024] [Revised: 03/01/2024] [Accepted: 03/05/2024] [Indexed: 04/09/2024]
Abstract
AIM Astrocytes respond to stressors by acquiring a reactive state characterized by changes in their morphology and function. Molecules underlying reactive astrogliosis, however, remain largely unknown. Given that several studies observed increase in the Amyloid Precursor Protein (APP) in reactive astrocytes, we here test whether APP plays a role in reactive astrogliosis. METHODS We investigated whether APP instigates reactive astroglios by examining in vitro and in vivo the morphology and function of naive and APP-deficient astrocytes in response to APP and well-established stressors. RESULTS Overexpression of APP in cultured astrocytes led to remodeling of the intermediate filament network, enhancement of cytokine production, and activation of cellular programs centered around the interferon (IFN) pathway, all signs of reactive astrogliosis. Conversely, APP deletion abrogated remodeling of the intermediate filament network and blunted expression of IFN-stimulated gene products in response to lipopolysaccharide. Following traumatic brain injury (TBI), mouse reactive astrocytes also exhibited an association between APP and IFN, while APP deletion curbed the increase in glial fibrillary acidic protein observed canonically in astrocytes in response to TBI. CONCLUSIONS The APP thus represents a candidate molecular inducer and regulator of reactive astrogliosis. This finding has implications for understanding pathophysiology of neurodegenerative and other diseases of the nervous system characterized by reactive astrogliosis and opens potential new therapeutic avenues targeting APP and its pathways to modulate reactive astrogliosis.
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Affiliation(s)
- Gretsen Velezmoro Jauregui
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Dragana Vukić
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- Faculty of Science, National Centre for Biomedical Research, Masaryk University, Brno, Czech Republic
| | - Isaac G Onyango
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
| | - Carlos Arias
- Department of Neurosciences, University of California San Diego, La Jolla, California, USA
| | - Jan S Novotný
- Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacky University Olomouc, Olomouc, Czech Republic
| | - Kateřina Texlová
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
| | - Shanshan Wang
- Veterans Affairs San Diego Healthcare System, San Diego, USA
- Department of Anesthesia, University of California San Diego, La Jolla, California, USA
| | | | - Natalie Polakova
- Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacky University Olomouc, Olomouc, Czech Republic
| | - Jana Zelinkova
- Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacky University Olomouc, Olomouc, Czech Republic
| | - Maria Čarna
- Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacky University Olomouc, Olomouc, Czech Republic
| | - Valentina Lacovich
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Brian P Head
- Veterans Affairs San Diego Healthcare System, San Diego, USA
- Department of Anesthesia, University of California San Diego, La Jolla, California, USA
| | | | - Martin Mistrik
- Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacky University Olomouc, Olomouc, Czech Republic
| | - Robert Zorec
- Laboratory of Neuroendocrinology, Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia
- Celica Biomedical, Technology Park, Ljubljana, Slovenia
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- Achucarro Centre for Neuroscience, IIKERBASQUE, Basque Foundation for Science, Bilbao, Spain
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning Province, China
| | - Liam Keegan
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Mary A O'Connell
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Robert Rissman
- Department of Neurosciences, University of California San Diego, La Jolla, California, USA
| | - Gorazd B Stokin
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
- Faculty of Medicine and Dentistry, Institute of Molecular and Translational Medicine, Palacky University Olomouc, Olomouc, Czech Republic
- Department of Neurology, Gloucestershire Royal Hospital, Gloucestershire NHS Foundation Trust, Gloucester, UK
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2
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Jauregui GV, Vukić D, Onyango IG, Arias C, Novotný JS, Texlová K, Wang S, Kovačovicova KL, Polakova N, Zelinkova J, Čarna M, Strašil VL, Head BP, Havas D, Mistrik M, Zorec R, Verkhratsky A, Keegan L, O'Connel M, Rissman R, Stokin GB. Amyloid precursor protein induces reactive astrogliosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.18.571817. [PMID: 38187544 PMCID: PMC10769227 DOI: 10.1101/2023.12.18.571817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
We present in vitro and in vivo evidence demonstrating that Amyloid Precursor Protein (APP) acts as an essential instigator of reactive astrogliosis. Cell-specific overexpression of APP in cultured astrocytes led to remodelling of the intermediate filament network, enhancement of cytokine production and activation of cellular programs centred around the interferon (IFN) pathway, all signs of reactive astrogliosis. Conversely, APP deletion in cultured astrocytes abrogated remodelling of the intermediate filament network and blunted expression of IFN stimulated gene (ISG) products in response to lipopolysaccharide (LPS). Following traumatic brain injury (TBI), mouse reactive astrocytes also exhibited an association between APP and IFN, while APP deletion curbed the increase in glial fibrillary acidic protein (GFAP) observed canonically in astrocytes in response to TBI. Thus, APP represents a molecular inducer and regulator of reactive astrogliosis.
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Affiliation(s)
- Gretsen Velezmoro Jauregui
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
| | - Dragana Vukić
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- National Centre for Biomedical Research, Faculty of Science, Masaryk University, Brno Czech Republic
| | - Isaac G Onyango
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
| | - Carlos Arias
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Jan S Novotný
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Kateřina Texlová
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
| | - Shanshan Wang
- Veterans Affairs San Diego Healthcare System, San Diego, USA
- Department of Anesthesia, University of California San Diego, San Diego, USA
| | | | - Natalie Polakova
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Jana Zelinkova
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Maria Čarna
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | | | - Brian P Head
- Veterans Affairs San Diego Healthcare System, San Diego, USA
- Department of Anesthesia, University of California San Diego, San Diego, USA
| | | | - Martin Mistrik
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
| | - Robert Zorec
- Laboratory of Neuroendocrinology - Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
- Celica Biomedical, Technology Park, Ljubljana, Slovenia
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- Achucarro Centre for Neuroscience, IIKERBASQUE, Basque Foundation for Science, Bilbao, Spain
- Department of Stem Cell Biology, State Research Institute Centre for innovative Medicine, Vilnius, Lithuania
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning Province, China
| | - Liam Keegan
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Mary O'Connel
- Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Robert Rissman
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Gorazd B Stokin
- Translational Ageing and Neuroscience Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czech Republic
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University Olomouc, Olomouc, Czech Republic
- Department of Neurology, Gloucestershire Royal Hospital, Gloucestershire NHS Foundation Trust, Gloucester, UK
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3
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Eckfeld C, Schoeps B, Häußler D, Frädrich J, Bayerl F, Böttcher JP, Knolle P, Heisz S, Prokopchuk O, Hauner H, Munkhbaatar E, Demir IE, Hermann CD, Krüger A. TIMP-1 is a novel ligand of Amyloid Precursor Protein and triggers a proinflammatory phenotype in human monocytes. J Cell Biol 2023; 222:213799. [PMID: 36629908 PMCID: PMC9837626 DOI: 10.1083/jcb.202206095] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 10/21/2022] [Accepted: 11/28/2022] [Indexed: 01/12/2023] Open
Abstract
The emerging cytokine tissue inhibitor of metalloproteinases-1 (TIMP-1) correlates with the progression of inflammatory diseases, including cancer. However, the effects of TIMP-1 on immune cell activation and underlying molecular mechanisms are largely unknown. Unbiased ligand-receptor-capture-screening revealed TIMP-1-interaction with Amyloid Precursor Protein (APP) family members, namely APP and Amyloid Precursor-like Protein-2 (APLP2), which was confirmed by pull-down assays and confocal microscopy. We found that TIMP-1 triggered glucose uptake and proinflammatory cytokine expression in human monocytes. In cancer patients, TIMP-1 expression positively correlated with proinflammatory cytokine expression and processes associated with monocyte activation. In pancreatic cancer, TIMP-1 plasma levels correlated with the monocyte activation marker sCD163, and the combined use of both clinically accessible plasma proteins served as a powerful prognostic indicator. Mechanistically, TIMP-1 triggered monocyte activation by its C-terminal domain and via APP as demonstrated by in vitro interference, in silico docking, and the employment of recombinant TIMP-1 variants. Identification of TIMP-1 as a trigger of monocyte activation opens new therapeutic perspectives for inflammatory diseases.
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Affiliation(s)
- Celina Eckfeld
- https://ror.org/02kkvpp62School of Medicine, Institute of Experimental Oncology and Therapy Research, Technical University of Munich, Munich, Germany
| | - Benjamin Schoeps
- https://ror.org/02kkvpp62School of Medicine, Institute of Experimental Oncology and Therapy Research, Technical University of Munich, Munich, Germany
| | - Daniel Häußler
- https://ror.org/02kkvpp62School of Medicine, Institute of Experimental Oncology and Therapy Research, Technical University of Munich, Munich, Germany
| | - Julian Frädrich
- https://ror.org/02kkvpp62School of Medicine, Institute of Experimental Oncology and Therapy Research, Technical University of Munich, Munich, Germany
| | - Felix Bayerl
- School of Medicine, Institute of Molecular Immunology, Technical University of Munich, Munich, Germany
| | - Jan Philipp Böttcher
- School of Medicine, Institute of Molecular Immunology, Technical University of Munich, Munich, Germany
| | - Percy Knolle
- School of Medicine, Institute of Molecular Immunology, Technical University of Munich, Munich, Germany
| | - Simone Heisz
- School of Life Sciences, Else Kröner-Fresenius-Center for Nutritional Medicine, Chair of Nutritional Medicine, Technical University of Munich, Freising-Weihenstephan, Germany
| | - Olga Prokopchuk
- https://ror.org/02kkvpp62School of Medicine, Institute of Experimental Oncology and Therapy Research, Technical University of Munich, Munich, Germany,Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Hans Hauner
- School of Life Sciences, Else Kröner-Fresenius-Center for Nutritional Medicine, Chair of Nutritional Medicine, Technical University of Munich, Freising-Weihenstephan, Germany,School of Life Sciences, Institute for Nutritional Medicine, Technical University of Munich, Munich, Germany
| | - Enkhtsetseg Munkhbaatar
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Ihsan Ekin Demir
- Department of Surgery, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Chris D. Hermann
- https://ror.org/02kkvpp62School of Medicine, Institute of Experimental Oncology and Therapy Research, Technical University of Munich, Munich, Germany
| | - Achim Krüger
- https://ror.org/02kkvpp62School of Medicine, Institute of Experimental Oncology and Therapy Research, Technical University of Munich, Munich, Germany,Correspondence to Achim Krüger:
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4
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Pfundstein G, Nikonenko AG, Sytnyk V. Amyloid precursor protein (APP) and amyloid β (Aβ) interact with cell adhesion molecules: Implications in Alzheimer’s disease and normal physiology. Front Cell Dev Biol 2022; 10:969547. [PMID: 35959488 PMCID: PMC9360506 DOI: 10.3389/fcell.2022.969547] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 07/07/2022] [Indexed: 11/16/2022] Open
Abstract
Alzheimer’s disease (AD) is an incurable neurodegenerative disorder in which dysfunction and loss of synapses and neurons lead to cognitive impairment and death. Accumulation and aggregation of neurotoxic amyloid-β (Aβ) peptides generated via amyloidogenic processing of amyloid precursor protein (APP) is considered to play a central role in the disease etiology. APP interacts with cell adhesion molecules, which influence the normal physiological functions of APP, its amyloidogenic and non-amyloidogenic processing, and formation of Aβ aggregates. These cell surface glycoproteins also mediate attachment of Aβ to the neuronal cell surface and induce intracellular signaling contributing to Aβ toxicity. In this review, we discuss the current knowledge surrounding the interactions of cell adhesion molecules with APP and Aβ and analyze the evidence of the critical role these proteins play in regulating the processing and physiological function of APP as well as Aβ toxicity. This is a necessary piece of the complex AD puzzle, which we should understand in order to develop safe and effective therapeutic interventions for AD.
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Affiliation(s)
- Grant Pfundstein
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | | | - Vladimir Sytnyk
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
- *Correspondence: Vladimir Sytnyk,
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5
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Guo Y, Wang Q, Chen S, Xu C. Functions of amyloid precursor protein in metabolic diseases. Metabolism 2021; 115:154454. [PMID: 33248065 DOI: 10.1016/j.metabol.2020.154454] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 11/02/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023]
Abstract
Amyloid precursor protein (APP) is a transmembrane precursor protein that is widely expressed in the central nervous system and peripheral tissues in the liver and pancreas, adipose tissue, and myotubes. APP can be cleaved by proteases in two different ways to produce a variety of short peptides, each with different physiological properties and functions. APP peptides generated by non-amyloidogenic processing can positively influence metabolism, while the peptides produced by amyloidogenic processing have the opposite effects. Here, we summarize the regulatory effects of APP and its cleavage peptides on metabolism in the central nervous system and peripheral tissues. In addition, abnormal expression and function of APP and APP-derived peptides are associated with metabolic diseases, such as type 2 diabetes, obesity, non-alcoholic fatty liver disease, and cardiovascular disease, and cancers. Pharmacological intervention of APP function or reduction of the production of peptides derived from amyloidogenic processing may be effective strategies for the prevention and treatment of Alzheimer's disease, and they may also provide new guidance for the treatment of metabolic diseases.
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Affiliation(s)
- Yanjun Guo
- Department of Gastroenterology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Qinqiu Wang
- Department of Gastroenterology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Shenghui Chen
- Department of Gastroenterology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Chengfu Xu
- Department of Gastroenterology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China.
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6
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Stakos DA, Stamatelopoulos K, Bampatsias D, Sachse M, Zormpas E, Vlachogiannis NI, Tual-Chalot S, Stellos K. The Alzheimer's Disease Amyloid-Beta Hypothesis in Cardiovascular Aging and Disease: JACC Focus Seminar. J Am Coll Cardiol 2020; 75:952-967. [PMID: 32130931 PMCID: PMC7042886 DOI: 10.1016/j.jacc.2019.12.033] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 12/02/2019] [Accepted: 12/03/2019] [Indexed: 12/12/2022]
Abstract
Aging-related cellular and molecular processes including low-grade inflammation are major players in the pathogenesis of cardiovascular disease (CVD) and Alzheimer's disease (AD). Epidemiological studies report an independent interaction between the development of dementia and the incidence of CVD in several populations, suggesting the presence of overlapping molecular mechanisms. Accumulating experimental and clinical evidence suggests that amyloid-beta (Aβ) peptides may function as a link among aging, CVD, and AD. Aging-related vascular and cardiac deposition of Αβ induces tissue inflammation and organ dysfunction, both important components of the Alzheimer's disease amyloid hypothesis. In this review, the authors describe the determinants of Aβ metabolism, summarize the effects of Aβ on atherothrombosis and cardiac dysfunction, discuss the clinical value of Αβ1-40 in CVD prognosis and patient risk stratification, and present the therapeutic interventions that may alter Aβ metabolism in humans.
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Affiliation(s)
- Dimitrios A Stakos
- Cardiology Department, Democritus University of Thrace, Alexandroupolis, Greece
| | - Kimon Stamatelopoulos
- Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Athens, Greece; Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Dimitrios Bampatsias
- Department of Clinical Therapeutics, National and Kapodistrian University of Athens School of Medicine, Athens, Greece
| | - Marco Sachse
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom; Medical School, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Eleftherios Zormpas
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Nikolaos I Vlachogiannis
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Simon Tual-Chalot
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Konstantinos Stellos
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom; Department of Cardiology, Freeman Hospital, Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom; NIHR Newcastle Biomedical Research Centre, Newcastle University and Newcastle upon Tyne NHS Foundation Trust, Newcastle upon Tyne, United Kingdom.
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7
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Neuner SM, Tcw J, Goate AM. Genetic architecture of Alzheimer's disease. Neurobiol Dis 2020; 143:104976. [PMID: 32565066 PMCID: PMC7409822 DOI: 10.1016/j.nbd.2020.104976] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/30/2020] [Accepted: 06/13/2020] [Indexed: 02/06/2023] Open
Abstract
Advances in genetic and genomic technologies over the last thirty years have greatly enhanced our knowledge concerning the genetic architecture of Alzheimer's disease (AD). Several genes including APP, PSEN1, PSEN2, and APOE have been shown to exhibit large effects on disease susceptibility, with the remaining risk loci having much smaller effects on AD risk. Notably, common genetic variants impacting AD are not randomly distributed across the genome. Instead, these variants are enriched within regulatory elements active in human myeloid cells, and to a lesser extent liver cells, implicating these cell and tissue types as critical to disease etiology. Integrative approaches are emerging as highly effective for identifying the specific target genes through which AD risk variants act and will likely yield important insights related to potential therapeutic targets in the coming years. In the future, additional consideration of sex- and ethnicity-specific contributions to risk as well as the contribution of complex gene-gene and gene-environment interactions will likely be necessary to further improve our understanding of AD genetic architecture.
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Affiliation(s)
- Sarah M Neuner
- Nash Department of Neuroscience, Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Julia Tcw
- Nash Department of Neuroscience, Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, USA
| | - Alison M Goate
- Nash Department of Neuroscience, Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, USA.
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8
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Dean B, Tsatsanis A, Lam LQ, Scarr E, Duce JA. Changes in cortical protein markers of iron transport with gender, major depressive disorder and suicide. World J Biol Psychiatry 2020; 21:119-126. [PMID: 30513246 DOI: 10.1080/15622975.2018.1555377] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Objectives: The objective of this study was to determine whether a breakdown in proteins regulating cortical iron homeostasis could be involved in the pathophysiology of mood disorders.Methods: Levels of select proteins responsible for cortical iron transport were quantitated by Western blotting of Brodmann's (BA) areas 6 and 10 from patients with major depressive disorder (n = 13), bipolar disorder (n = 12) and age/sex matched controls (n = 13).Results: We found the inactive form of ceruloplasmin was lower in BA 6 from males compared to females. Levels of copper containing ceruloplasmin was lower in BA 6 from suicide completers whilst levels of amyloid precursor protein, TAU and transferrin were higher in BA 10 from those individuals. The level of prion protein was lower in BA 6 from subjects with major depressive disorder.Conclusions: Our data suggests that perturbation in cortical iron transport proteins is not prevalent in mood disorders. By contrast, our data suggests changes in iron transport proteins in BA 6 and BA 10 are present after suicide completion. If these changes were present before death, they could have had a role in the genesis of the contemplation and completion of suicide.
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Affiliation(s)
- Brian Dean
- The Molecular Psychiatry Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, Australia.,The Centre for Mental Health, the Faculty of Health, Arts and Design, Swinburne University, Hawthorne, Australia
| | - Andrew Tsatsanis
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, Parkville, Australia.,School of Biomedical Sciences, University of Leeds, Leeds, UK
| | - Linh Q Lam
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, Parkville, Australia.,Neuropharmacology Laboratory, Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, Australia
| | - Elizabeth Scarr
- The Molecular Psychiatry Laboratory, The Florey Institute of Neuroscience and Mental Health, Parkville, Australia.,Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Australia
| | - James A Duce
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, Parkville, Australia.,School of Biomedical Sciences, University of Leeds, Leeds, UK.,The ALBORADO Drug Discovery Institute, University of Cambridge, Cambridge, UK
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9
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Okamoto M, Gray JD, Larson CS, Kazim SF, Soya H, McEwen BS, Pereira AC. Riluzole reduces amyloid beta pathology, improves memory, and restores gene expression changes in a transgenic mouse model of early-onset Alzheimer's disease. Transl Psychiatry 2018; 8:153. [PMID: 30108205 PMCID: PMC6092426 DOI: 10.1038/s41398-018-0201-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 06/08/2018] [Indexed: 01/21/2023] Open
Abstract
Alzheimer's disease (AD) represents a major healthcare burden with no effective treatment. The glutamate modulator, riluzole, was shown to reverse many AD-related gene expression changes and improve cognition in aged rats. However, riluzole's effect on amyloid beta (Aβ) pathology, a major histopathological hallmark of AD, remains unclear. 5XFAD transgenic mice, which harbor amyloid β precursor protein (APP) and presenilin mutations and exhibit early Aβ accumulation, were treated with riluzole from 1 to 6 months of age. Riluzole significantly enhanced cognition and reduced Aβ42, Aβ40, Aβ oligomers levels, and Aβ plaque load in 5XFAD mice. RNA-Sequencing showed that riluzole reversed many gene expression changes observed in the hippocampus of 5XFAD mice, predominantly in expression of canonical gene markers for microglia, specifically disease-associated microglia (DAM), as well as neurons and astrocytes. Central to the cognitive improvements observed, riluzole reversed alterations in NMDA receptor subunits gene expression, which are essential for learning and memory. These data demonstrate that riluzole exerts a disease modifying effect in an Aβ mouse model of early-onset familial AD.
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Affiliation(s)
- Masahiro Okamoto
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, 10065, USA
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sports Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8574, Japan
| | - Jason D Gray
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, 10065, USA
| | - Chloe S Larson
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, 10065, USA
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Syed Faraz Kazim
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Hideaki Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sports Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8574, Japan
| | - Bruce S McEwen
- Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, 10065, USA
| | - Ana C Pereira
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
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10
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Amyloid precursor protein modulates macrophage phenotype and diet-dependent weight gain. Sci Rep 2017; 7:43725. [PMID: 28262782 PMCID: PMC5338020 DOI: 10.1038/srep43725] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/26/2017] [Indexed: 02/07/2023] Open
Abstract
It is well known that mutations in the gene coding for amyloid precursor protein are responsible for autosomal dominant forms of Alzheimer’s disease. Proteolytic processing of the protein leads to a number of metabolites including the amyloid beta peptide. Although brain amyloid precursor protein expression and amyloid beta production are associated with the pathophysiology of Alzheimer’s disease, it is clear that amyloid precursor protein is expressed in numerous cell types and tissues. Here we demonstrate that amyloid precursor protein is involved in regulating the phenotype of both adipocytes and peripheral macrophages and is required for high fat diet-dependent weight gain in mice. These data suggest that functions of this protein include modulation of the peripheral immune system and lipid metabolism. This biology may have relevance not only to the pathophysiology of Alzheimer’s disease but also diet-associated obesity.
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Manocha GD, Floden AM, Rausch K, Kulas JA, McGregor BA, Rojanathammanee L, Puig KR, Puig KL, Karki S, Nichols MR, Darland DC, Porter JE, Combs CK. APP Regulates Microglial Phenotype in a Mouse Model of Alzheimer's Disease. J Neurosci 2016; 36:8471-86. [PMID: 27511018 PMCID: PMC4978805 DOI: 10.1523/jneurosci.4654-15.2016] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 05/20/2016] [Accepted: 06/24/2016] [Indexed: 01/13/2023] Open
Abstract
UNLABELLED Prior work suggests that amyloid precursor protein (APP) can function as a proinflammatory receptor on immune cells, such as monocytes and microglia. Therefore, we hypothesized that APP serves this function in microglia during Alzheimer's disease. Although fibrillar amyloid β (Aβ)-stimulated cytokine secretion from both wild-type and APP knock-out (mAPP(-/-)) microglial cultures, oligomeric Aβ was unable to stimulate increased secretion from mAPP(-/-) cells. This was consistent with an ability of oligomeric Aβ to bind APP. Similarly, intracerebroventricular infusions of oligomeric Aβ produced less microgliosis in mAPP(-/-) mice compared with wild-type mice. The mAPP(-/-) mice crossed to an APP/PS1 transgenic mouse line demonstrated reduced microgliosis and cytokine levels and improved memory compared with wild-type mice despite robust fibrillar Aβ plaque deposition. These data define a novel function for microglial APP in regulating their ability to acquire a proinflammatory phenotype during disease. SIGNIFICANCE STATEMENT A hallmark of Alzheimer's disease (AD) brains is the accumulation of amyloid β (Aβ) peptide within plaques robustly invested with reactive microglia. This supports the notion that Aβ stimulation of microglial activation is one source of brain inflammatory changes during disease. Aβ is a cleavage product of the ubiquitously expressed amyloid precursor protein (APP) and is able to self-associate into a wide variety of differently sized and structurally distinct multimers. In this study, we demonstrate both in vitro and in vivo that nonfibrillar, oligomeric forms of Aβ are able to interact with the parent APP protein to stimulate microglial activation. This provides a mechanism by which metabolism of APP results in possible autocrine or paracrine Aβ production to drive the microgliosis associated with AD brains.
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Affiliation(s)
- Gunjan D Manocha
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Angela M Floden
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Keiko Rausch
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Joshua A Kulas
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Brett A McGregor
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Lalida Rojanathammanee
- Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000 Thailand
| | - Kelley R Puig
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Kendra L Puig
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Sanjib Karki
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, St. Louis, Missouri 63121-4400, and
| | - Michael R Nichols
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, St. Louis, Missouri 63121-4400, and
| | - Diane C Darland
- Department of Biology, University of North Dakota, Grand Forks, North Dakota 58202
| | - James E Porter
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203
| | - Colin K Combs
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58203,
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Altered Innate Immune and Glial Cell Responses to Inflammatory Stimuli in Amyloid Precursor Protein Knockout Mice. PLoS One 2015; 10:e0140210. [PMID: 26447481 PMCID: PMC4598170 DOI: 10.1371/journal.pone.0140210] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 09/23/2015] [Indexed: 11/30/2022] Open
Abstract
Amyloid precursor protein (APP) and its cleaved products have been reported to have important functions in CNS health, including in memory and synapse formation, cell survival and neuroprotection. Furthermore APP and its cleaved products have been shown to be transiently increased in response to various CNS stressors, suggesting a role in response to acute cellular injury. In an attempt to further understand the function of APP in response to CNS injury, we have used intracranial LPS injection as an inflammatory injury model in APP knock out mice (APPKO). Our data show that innate immune responses to LPS injection is significantly blunted in APPKO mice compared to APP sufficient wild type (BL6) mice. Morphologically, glial cells in APPKO mice appear less reactive, with shorter ramified processes and smaller cell bodies in response to LPS. Additionally, quantitative RT-PCR analysis for several glia markers and innate immune cytokine levels (e.g. TNFα, IL-6, IL-1β and IL-10) showed significantly reduced expression levels in LPS injected APPKO mice. In vitro cell culture assays confirmed this attenuated response to LPS stimulation by primary microglial cells isolated from APPKO mice. Our data suggests that APP full length protein and/or its cleaved products are necessary to mount a complete and effective innate immune cell response to inflammatory injury.
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Puig KL, Manocha GD, Combs CK. Amyloid precursor protein mediated changes in intestinal epithelial phenotype in vitro. PLoS One 2015; 10:e0119534. [PMID: 25742317 PMCID: PMC4351204 DOI: 10.1371/journal.pone.0119534] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 01/28/2015] [Indexed: 12/13/2022] Open
Abstract
Background Although APP and its proteolytic metabolites have been well examined in the central nervous system, there remains limited information of their functions outside of the brain. For example, amyloid precursor protein (APP) and amyloid beta (Aβ) immunoreactivity have both been demonstrated in intestinal epithelial cells. Based upon the critical role of these cells in absorption and secretion, we sought to determine whether APP or its metabolite amyloid β (Aβ), had a definable function in these cells. Methodology/Principal Findings The human colonic epithelial cell line, Caco-2 cells, were cultured to examine APP expression and Aβ secretion, uptake, and stimulation. Similar to human colonic epithelium stains, Caco-2 cells expressed APP. They also secreted Aβ 1-40 and Aβ 1-42, with LPS stimulating higher concentrations of Aβ 1-40 secretion. The cells also responded to Aβ 1-40 stimulation by increasing IL-6 cytokine secretion and decreasing cholesterol uptake. Conversely, stimulation with a sAPP-derived peptide increased cholesterol uptake. APP was associated with CD36 but not FATP4 in co-IP pull down experiments from the Caco-2 cells. Moreover, stimulation of APP with an agonist antibody acutely decreased CD36-mediated cholesterol uptake. Conclusions/Significance APP exists as part of a multi-protein complex with CD36 in human colonic epithelial cells where its proteolytic fragments have complex, reciprocal roles in regulating cholesterol uptake. A biologically active peptide fragment from the N-terminal derived, sAPP, potentiated cholesterol uptake while the β secretase generated product, Aβ1-40, attenuated it. These data suggest that APP is important in regulating intestinal cholesterol uptake in a fashion dependent upon specific proteolytic pathways. Moreover, this biology may be applicable to cells beyond the gastrointestinal tract.
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Affiliation(s)
- Kendra L. Puig
- Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, United States of America
| | - Gunjan D. Manocha
- Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, United States of America
| | - Colin K. Combs
- Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, United States of America
- * E-mail:
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Condic M, Oberstein TJ, Herrmann M, Reimann MC, Kornhuber J, Maler JM, Spitzer P. N-truncation and pyroglutaminylation enhances the opsonizing capacity of Aβ-peptides and facilitates phagocytosis by macrophages and microglia. Brain Behav Immun 2014; 41:116-25. [PMID: 24876064 DOI: 10.1016/j.bbi.2014.05.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Revised: 04/18/2014] [Accepted: 05/03/2014] [Indexed: 10/25/2022] Open
Abstract
Abnormal accumulations of amyloid-β (Aβ)-peptides are one of the pathological hallmarks of Alzheimer's disease (AD). The precursor of the Aβ-peptides, the amyloid precursor protein (APP), is also found in peripheral blood cells, but its function in these cells remains elusive. We previously observed that mononuclear phagocytes release Aβ-peptides during activation and phagocytosis, suggesting a physiologic role in inflammatory processes. Here, we show that supplementing the media with soluble N-terminally truncated Aβ(2-40) and Aβ(2-42) as well as Aβ(1-42) induced the phagocytosis of polystyrene particles (PSPs) by primary human monocytes. If the PSPs were pre-incubated with Aβ-peptides, phagocytosis was induced by all tested Aβ-peptide species. N-terminally truncated Aβ(x-42) induced the phagocytosis of PSPs significantly more effectively than did Aβ(x-40). Similarly, the phagocytosis of Escherichia coli by GM-CSF- and M-CSF-elicited macrophages as well as microglia was particularly facilitated by pre-incubation with N-terminally truncated Aβ(x-42). The proinflammatory polarization of monocytes was indicated by the reduced MSRI expression and IL-10 secretion after phagocytosis of PSPs coated with Aβ(1-42), Aβ(2-42) and Aβ(3p-42). Polarization of the macrophages by GM-CSF reduced the phagocytic activity, but it did not affect the capabilities of Aβ-peptides to opsonize prey. Taken together, Aβ-peptides support phagocytosis as soluble factors and act as opsonins. Differential effects among the Aβ-peptide variants point to distinct mechanisms of interaction among monocytes/macrophages, prey and Aβ-peptides. A proinflammatory polarization induced by the phagocytosis of Aβ-peptide coated particles may provide a model for the chronic inflammatory reaction and sustained plaque deposition in AD.
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Affiliation(s)
- Mateja Condic
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Timo Jan Oberstein
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Martin Herrmann
- Department of Medicine III, Institute for Clinical Immunology, Friedrich-Alexander-University Erlangen-Nuremberg, Gluecksstraße 4a, D-91054 Erlangen, Germany
| | - Mareike Carola Reimann
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Johannes Kornhuber
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Juan Manuel Maler
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany
| | - Philipp Spitzer
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany.
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Wang J, Yan K, Wu ZQ, Zheng CY, Xu RX, Chen LH, Wen ZM, Zhao HQ, Ma QH. TDP-43 interaction with the intracellular domain of amyloid precursor protein induces p53-associated apoptosis. Neurosci Lett 2014; 569:131-6. [DOI: 10.1016/j.neulet.2014.03.075] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 03/10/2014] [Accepted: 03/29/2014] [Indexed: 12/13/2022]
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Amyloid precursor protein and proinflammatory changes are regulated in brain and adipose tissue in a murine model of high fat diet-induced obesity. PLoS One 2012; 7:e30378. [PMID: 22276186 PMCID: PMC3261903 DOI: 10.1371/journal.pone.0030378] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 12/19/2011] [Indexed: 11/23/2022] Open
Abstract
Background Middle age obesity is recognized as a risk factor for Alzheimer's disease (AD) although a mechanistic linkage remains unclear. Based upon the fact that obese adipose tissue and AD brains are both areas of proinflammatory change, a possible common event is chronic inflammation. Since an autosomal dominant form of AD is associated with mutations in the gene coding for the ubiquitously expressed transmembrane protein, amyloid precursor protein (APP) and recent evidence demonstrates increased APP levels in adipose tissue during obesity it is feasible that APP serves some function in both disease conditions. Methodology/Principal Findings To determine whether diet-induced obesity produced proinflammatory changes and altered APP expression in brain versus adipose tissue, 6 week old C57BL6/J mice were maintained on a control or high fat diet for 22 weeks. Protein levels and cell-specific APP expression along with markers of inflammation and immune cell activation were compared between hippocampus, abdominal subcutaneous fat and visceral pericardial fat. APP stimulation-dependent changes in macrophage and adipocyte culture phenotype were examined for comparison to the in vivo changes. Conclusions/Significance Adipose tissue and brain from high fat diet fed animals demonstrated increased TNF-α and microglial and macrophage activation. Both brains and adipose tissue also had elevated APP levels localizing to neurons and macrophage/adipocytes, respectively. APP agonist antibody stimulation of macrophage cultures increased specific cytokine secretion with no obvious effects on adipocyte culture phenotype. These data support the hypothesis that high fat diet-dependent obesity results in concomitant pro-inflammatory changes in brain and adipose tissue that is characterized, in part, by increased levels of APP that may be contributing specifically to inflammatory changes that occur.
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17
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Amyloid precursor protein expression modulates intestine immune phenotype. J Neuroimmune Pharmacol 2011; 7:215-30. [PMID: 22124967 DOI: 10.1007/s11481-011-9327-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 11/14/2011] [Indexed: 12/16/2022]
Abstract
Amyloid precursor protein (APP) is widely expressed across many tissue and cell types. Proteolytic processing of the protein gives rise to a plethora of protein fragments with varied biological activities. Although a large amount of data has been generated describing the metabolism of the protein in neurons, its role in regulating the phenotype of other cells remains unclear. Based upon prior work demonstrating that APP regulates the activation phenotype of monocytic lineage cells, we hypothesized that APP can regulate macrophage activation phenotype in tissues other than brain. Ileums of the small intestines from C57BL6/J wild type and APP(-/-) mice were compared as a representative tissue normally associated with abundant macrophage infiltration. APP(-/-) intestines demonstrated diminished CD68 immunoreactivity compared to wild type mice. This correlated with significantly less cyclooxygenase-2 (cox-2), CD68, CD40, CD11c, and βIII-tubulin protein levels. Peritoneal macrophages from APP(-/-) mice demonstrated decreased in vitro migratory ability compared to wild type cells and diminished basal KC cytokine secretion. Whereas, APP(-/-) intestinal macrophages had an increase in basal KC cytokine secretion compared to wild type cells. Conversely, there was a significant decrease in multiple cytokine levels in APP(-/-) compared to wild type ileums. Finally, APP(-/-) mice demonstrated impaired absorption and increased motility compared to wild type mice. These data demonstrate the APP expression regulates immune cell secretions and phenotype and intestinal function. This data set describes a novel function for this protein or its metabolites that may be relevant not only for Alzheimer's disease but a range of immune-related disorders.
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18
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Lack of alpha-synuclein modulates microglial phenotype in vitro. Neurochem Res 2011; 36:994-1004. [PMID: 21384098 DOI: 10.1007/s11064-011-0439-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2011] [Indexed: 10/18/2022]
Abstract
Alpha (α)-synuclein neuronal effects are continually being defined although its role in regulating glial phenotypes remains unclear. An ability to regulate microglial activation was investigated using primary cultures from wild type and α-synuclein deficient mice (Snca-/-). Snca-/- microglia demonstrated increased secretion of the cytokine tumor necrosis factor-alpha (TNF-α), impaired phagocytic ability, elevated prostaglandin levels, and increased protein levels of key enzymes in lipid-mediated signaling events, cytosolic phospholipase (cPLA(2)), cyclooxygenase-2 (Cox-2) and phospholipase D2 (PLD2) when compared to wild type cells. Increased cytokine secretion and cPLA(2) and Cox-2 levels in Snca-/- microglia were partially attenuated by inhibiting PLD-dependent signaling with n-butanol treatment.
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19
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Chang KA, Suh YH. Possible roles of amyloid intracellular domain of amyloid precursor protein. BMB Rep 2011; 43:656-63. [PMID: 21034527 DOI: 10.5483/bmbrep.2010.43.10.656] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Amyloid precursor protein (APP), which is critically involved in the pathogenesis of Alzheimer's disease (AD), is cleaved by gamma/epsilon-secretase activity and results in the generation of different lengths of the APP Intracellular C-terminal Domain (AICD). In spite of its small size and short half-life, AICD has become the focus of studies on AD pathogenesis. Recently, it was demonstrated that AICD binds to different intracellular binding partners ('adaptor protein'), which regulate its stability and cellular localization. In terms of choice of adaptor protein, phosphorylation seems to play an important role. AICD and its various adaptor proteins are thought to take part in various cellular events, including regulation of gene transcription, apoptosis, calcium signaling, growth factor, and NF-κB pathway activation, as well as the production, trafficking, and processing of APP, and the modulation of cytoskeletal dynamics. This review discusses the possible roles of AICD in the pathogenesis of neurodegenerative diseases including AD.
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Affiliation(s)
- Keun-A Chang
- Department of Pharmacology, College of Medicine, Neuroscience Research Institute, MRC, Seoul National University, Seoul 110-799, Korea
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Van De Parre TJL, Guns PJDF, Fransen P, Martinet W, Bult H, Herman AG, De Meyer GRY. Attenuated atherogenesis in apolipoprotein E-deficient mice lacking amyloid precursor protein. Atherosclerosis 2011; 216:54-8. [PMID: 21316678 DOI: 10.1016/j.atherosclerosis.2011.01.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 01/17/2011] [Accepted: 01/18/2011] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Recent evidence suggests that amyloid precursor protein (APP) is overexpressed in atherosclerosis-prone regions of mouse aorta. We therefore investigated in the present study whether APP has a role in the progression and composition of atherosclerotic plaques. METHODS AND RESULTS Apolipoprotein E-deficient (apoE(-/-)) mice were crossbred with animals lacking APP (APP(-/-)). After 16 weeks on a Western-type diet, apoE(-/-) and APP(-/-)/apoE(-/-) mice showed similar cholesterol levels. However, atherosclerotic plaque size was significantly reduced in the distal thoracic aorta (90% reduction) and abdominal aorta (75% reduction) of APP(-/-)/apoE(-/-) mice as compared to apoE(-/-). Plaques at the level of the aortic valves were not different in size, but showed a more stable phenotype in APP(-/-)/apoE(-/-) mice, as indicated by a reduced macrophage content, an increased amount of collagen and a thicker fibrous cap. CONCLUSION Our findings provide evidence that lack of APP attenuates atherogenesis and leads to plaque stability.
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Affiliation(s)
- Tim J L Van De Parre
- Division of Pharmacology, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Wilrijk, Belgium
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Microglial phenotype is regulated by activity of the transcription factor, NFAT (nuclear factor of activated T cells). J Neurosci 2010; 30:9641-6. [PMID: 20631193 DOI: 10.1523/jneurosci.0828-10.2010] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The transcription factor family, nuclear factor of activated T cells (NFAT), regulates immune cell phenotype. Four different calcium/calmodulin-regulated isoforms have been identified in the periphery, but isoform expression in microglia, the resident immune cells of the CNS, has not been fully defined. In this study microglial NFAT isoform expression and involvement in regulating inflammatory responses in murine primary microglia culture was examined. Western blot analysis demonstrated robust detection of NFATc1 and c2 isoforms in microglia. Electrophoretic mobility shift assays demonstrated increased NFAT-DNA binding from nuclear extracts of lipopolysaccharide (LPS) stimulated microglia. Moreover, LPS-stimulated microglia behaved similarly to T cell receptor agonist antibody-stimulated Jurkat cells demonstrating a transient increase in NFAT-driven luciferase reporter gene expression. LPS-induced NFAT-luciferase activity in microglia was attenuated by pretreatment with tat-VIVIT, a cell-permeable NFAT inhibitory peptide. Furthermore, LPS-mediated secretion of microglial cytokines, TNF-alpha and MCP-1, was decreased by treatment with tat-VIVIT but not with tat-VEET, a negative control peptide. These results demonstrate that NFAT plays a role in regulating proinflammatory responses in cultured murine microglia.
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22
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Venkataramani V, Rossner C, Iffland L, Schweyer S, Tamboli IY, Walter J, Wirths O, Bayer TA. Histone deacetylase inhibitor valproic acid inhibits cancer cell proliferation via down-regulation of the alzheimer amyloid precursor protein. J Biol Chem 2010; 285:10678-89. [PMID: 20145244 PMCID: PMC2856276 DOI: 10.1074/jbc.m109.057836] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 02/05/2010] [Indexed: 11/06/2022] Open
Abstract
The beta-amyloid precursor protein (APP) represents a type I transmembrane glycoprotein that is ubiquitously expressed. In the brain, it is a key player in the molecular pathogenesis of Alzheimer disease. Its physiological function is however less well understood. Previous studies showed that APP is up-regulated in prostate, colon, pancreatic tumor, and oral squamous cell carcinoma. In this study, we show that APP has an essential role in growth control of pancreatic and colon cancer. Abundant APP staining was found in human pancreatic adenocarcinoma and colon cancer tissue. Interestingly, treating pancreatic and colon cancer cells with valproic acid (VPA, 2-propylpentanoic acid), a known histone deacetylase (HDAC) inhibitor, leads to up-regulation of GRP78, an endoplasmic reticulum chaperone immunoglobulin-binding protein. GRP78 is involved in APP maturation and inhibition of tumor cell growth by down-regulation of APP and secreted soluble APPalpha. Trichostatin A, a pan-HDAC inhibitor, also lowered APP and increased GRP78 levels. In contrast, treating cells with valpromide, a VPA derivative lacking HDAC inhibitory properties, had no effect on APP levels. VPA did not modify the level of epidermal growth factor receptor, another type I transmembrane protein, and APLP2, a member of the APP family, demonstrating the specificity of the VPA effect on APP. Small interfering RNA-mediated knockdown of APP also resulted in significantly decreased cell growth. Based on these observations, the data suggest that APP down-regulation via HDAC inhibition provides a novel mechanism for pancreatic and colon cancer therapy.
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Affiliation(s)
- Vivek Venkataramani
- From the Department of Molecular Psychiatry, Alzheimer Ph.D. Graduate School, and
| | - Christian Rossner
- From the Department of Molecular Psychiatry, Alzheimer Ph.D. Graduate School, and
| | - Lara Iffland
- From the Department of Molecular Psychiatry, Alzheimer Ph.D. Graduate School, and
| | - Stefan Schweyer
- Department of Pathology, University of Goettingen, 37075 Goettingen and
| | - Irfan Y. Tamboli
- the Department of Molecular Cell Biology, University of Bonn, 53127 Bonn, Germany
| | - Jochen Walter
- the Department of Molecular Cell Biology, University of Bonn, 53127 Bonn, Germany
| | - Oliver Wirths
- From the Department of Molecular Psychiatry, Alzheimer Ph.D. Graduate School, and
| | - Thomas A. Bayer
- From the Department of Molecular Psychiatry, Alzheimer Ph.D. Graduate School, and
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Sondag CM, Combs CK. Adhesion of monocytes to type I collagen stimulates an APP-dependent proinflammatory signaling response and release of Abeta1-40. J Neuroinflammation 2010; 7:22. [PMID: 20302643 PMCID: PMC2850892 DOI: 10.1186/1742-2094-7-22] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Accepted: 03/19/2010] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Amyloid precursor protein (APP) is a ubiquitously expressed cell surface protein reported to be involved in mediating cell-cell or cell-matrix interactions. Prior work has demonstrated that APP co-localizes with beta1 integrin in different cell types. METHODS In an effort to determine the function of APP on monocytic lineage cells, in particular, the human monocyte cell line, THP-1, was used to assess the role of APP during adhesion to the extracelluar matrix component type I collagen. RESULTS Pull-down assays demonstrated that THP-1 adhesion to collagen stimulated a tyrosine kinase-associated signaling response which included subsequent phosphorylation of p38 MAP kinase and increased association of APP with alpha2beta1 integrin, specifically. In addition, cell adhesion was dependent upon APP expression since APP siRNA knockdown attenuated THP-1 adhesion to collagen compared to mock transfected controls. One consequence of the tyrosine kinase-dependent signaling response was increased secretion of interleukin-1beta (IL-1beta) and Abeta1-40 but not the Abeta1-42 fragment of APP. Increased secretion of IL-1beta was dependent upon p38 MAP kinase activity while Abeta1-40 secretion required Src family kinase activity since the specific p38 inhibitor, SB202190, and the Src family kinase inhibitor, PP2, attenuated IL-1beta and Abeta1-40 secretion, respectively. CONCLUSIONS These data demonstrate that APP is involved in classic integrin-dependent tyrosine kinase-associated adhesion and activation of peripheral monocytic cells. Moreover, divergent APP-dependent signaling is required for increased secretion of both IL-1beta and Abeta1-40 as a component of the adhesion-dependent change in phenotype. This suggests that APP may have a broad role in not only mediating cell-matrix adhesion but also in the function of peripheral immune cells.
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Affiliation(s)
- Cindy M Sondag
- Department of Pharmacology, Physiology & Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
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Amyloid precursor protein mediates a tyrosine kinase-dependent activation response in endothelial cells. J Neurosci 2009; 29:14451-62. [PMID: 19923279 DOI: 10.1523/jneurosci.3107-09.2009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Amyloid precursor protein (APP) is a ubiquitously expressed type 1 integral membrane protein. It has the ability to bind numerous extracellular matrix components and propagate signaling responses via its cytoplasmic phospho-tyrosine, (682)YENPTY(687), binding motif. We recently demonstrated increased protein levels of APP, phosphorylated APP (Tyr682), and beta-amyloid (Abeta) in brain vasculature of atherosclerotic and Alzheimer's disease (AD) tissue colocalizing primarily within the endothelial layer. This study demonstrates similar APP changes in peripheral vasculature from human and mouse apoE(-/-) aorta, suggesting that APP-related changes are not restricted to brain vasculature. Therefore, primary mouse aortic endothelial cells and human umbilical vein endothelial cells were used as a model system to examine the function of APP in endothelial cells. APP multimerization with an anti-N-terminal APP antibody, 22C11, to simulate ligand binding stimulated an Src kinase family-dependent increase in protein phospho-tyrosine levels, APP phosphorylation, and Abeta secretion. Furthermore, APP multimerization stimulated increased protein levels of the proinflammatory proteins, cyclooxygenase-2 and vascular cell adhesion molecule-1 also in an Src kinase family-dependent manner. Endothelial APP was also involved in mediating monocytic cell adhesion. Collectively, these data demonstrate that endothelial APP regulates immune cell adhesion and stimulates a tyrosine kinase-dependent response driving acquisition of a reactive endothelial phenotype. These APP-mediated events may serve as therapeutic targets for intervention in progressive vascular changes common to cerebrovascular disease and AD.
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Tamayev R, Zhou D, D'Adamio L. The interactome of the amyloid beta precursor protein family members is shaped by phosphorylation of their intracellular domains. Mol Neurodegener 2009; 4:28. [PMID: 19602287 PMCID: PMC2723102 DOI: 10.1186/1750-1326-4-28] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Accepted: 07/14/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Brain tissue from patients with Alzheimer's disease has shown an increase of phosphorylation of Tyr-682, located on the conserved Y682ENPTY motif, and Thr-668 residues, both in the intracellular domain (AID) of amyloid beta precursor protein (APP), although the role of these two residues is not yet known. RESULTS Here, we report that the phosphorylation status of Tyr-682, and in some cases Thr-668, shapes the APP interactome. It creates a docking site for SH2-domain containing proteins, such as ShcA, ShcB, ShcC, Grb7, Grb2, as well as adapter proteins, such as Crk and Nck, that regulate important biological processes, cytosolic tyrosine kinases, such as Abl, Lyn and Src, which regulate signal transduction pathways, and enzymes that control phosphatidylinositols levels and signaling, such as PLC-gamma. At the same time, it either reduces (like for JIP1, NUMB, NUMBL and ARH) or abolishes (like for Fe65, Fe65L1 and Fe65L2) binding of other APP interactors. Phosphorylation of Thr-668, unlike Tyr-682, does not seem to affect APP's ability to interact with the various proteins, with Pin1 and X11 being the exclusions. We also found that there are some differences between the interactions to AID and to ALID1 and ALID2, its two homologues. CONCLUSION Our data indicates that APP can regulate diverse cellular processes and that, vice versa, a network of signaling events can impact APP processing. Our results also suggest that phosphorylation of the APP Intracellular Domain will dramatically shape the APP interactome and, consequently, will regulate APP processing, APP transport and APP/AID-mediated functions.
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Affiliation(s)
- Robert Tamayev
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA.
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Takayama KI, Tsutsumi S, Suzuki T, Horie-Inoue K, Ikeda K, Kaneshiro K, Fujimura T, Kumagai J, Urano T, Sakaki Y, Shirahige K, Sasano H, Takahashi S, Kitamura T, Ouchi Y, Aburatani H, Inoue S. Amyloid precursor protein is a primary androgen target gene that promotes prostate cancer growth. Cancer Res 2009; 69:137-42. [PMID: 19117996 DOI: 10.1158/0008-5472.can-08-3633] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Androgen receptor (AR) is a critical transcription factor that regulates various target genes and contributes to the pathophysiology of prostate cancer hormone dependently. Here, we identify amyloid precursor protein (APP) as a primary androgen target through chromatin immunoprecipitation (ChIP) combined with genome tiling array analysis (ChIP-chip). ChIP-treated DNA were obtained from prostate cancer LNCaP cells with R1881 or vehicle treatment using AR or acetylated histone H3 antibodies. Ligand-dependent AR binding was further enriched by PCR subtraction. Using chromosome 21/22 arrays, we identified APP as one of the androgen-regulated genes with adjacent functional AR binding sites. APP expression is androgen-inducible in LNCaP cells and APP immunoreactivity was correlated with poor prognosis in patients with prostate cancer. Gain-of-function and loss-of-function studies revealed that APP promotes the tumor growth of prostate cancer. The present study reveals a novel APP-mediated pathway responsible for the androgen-dependent growth of prostate cancer. Our findings will indicate that APP could be a potential molecular target for the diagnosis and treatment of prostate cancer.
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Affiliation(s)
- Ken-ichi Takayama
- Department of Geriatric Medicine, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
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Vaisar T, Kassim SY, Gomez IG, Green PS, Hargarten S, Gough PJ, Parks WC, Wilson CL, Raines EW, Heinecke JW. MMP-9 sheds the beta2 integrin subunit (CD18) from macrophages. Mol Cell Proteomics 2008; 8:1044-60. [PMID: 19116209 DOI: 10.1074/mcp.m800449-mcp200] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Activated macrophages are essential effectors of immunity and a rich source of matrix metalloproteinase-9 (MMP-9; gelatinase B). To search for cellular substrates of the enzyme, we subjected wild-type macrophages and macrophages expressing an autoactivating form of pro-MMP-9 (M9A macrophages) to proteomics analysis. Two-dimensional liquid chromatography together with tandem mass spectrometry identified 467 proteins in medium conditioned by M9A and/or wild-type macrophages. Subtractive proteomics identified 18 candidate MMP-9 substrates. Biochemical studies confirmed that two transmembrane proteins, beta(2) integrin subunit (CD18) and amyloid protein precursor (APP), were enriched in the medium of M9A macrophages. To identify potential cleavage sites, we synthesized an overlapping library of peptides that spanned 60 residues of the ectodomain and transmembrane domain of beta(2) integrin. Active MMP-9 cleaved a single peptide, ECVKGPNVAAIVGGT, at residues corresponding to Ala(705) and Ile(706) of the beta(2) integrin. Peptides corresponding to this cleavage site were detected by tandem mass spectrometric analysis only in medium from M9A macrophages, strongly supporting the proposal that beta(2) integrin is shed by autoactivating MMP-9. Our observations indicate that subtractive proteomics in concert with peptide substrate mapping is a powerful approach for identifying proteolytic substrates and suggest that MMP-9 plays previously unsuspected roles in the regulation and shedding of beta(2) integrin.
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Affiliation(s)
- Tomás Vaisar
- Department of Medicine, School of Medicine, University of Washington, Seattle, Washington 98195, USA
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29
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Austin SA, Combs CK. Amyloid precursor protein mediates monocyte adhesion in AD tissue and apoE(-)/(-) mice. Neurobiol Aging 2008; 31:1854-66. [PMID: 19058878 DOI: 10.1016/j.neurobiolaging.2008.10.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Revised: 10/07/2008] [Accepted: 10/17/2008] [Indexed: 10/21/2022]
Abstract
Amyloid precursor protein (APP) is a type 1 integral membrane protein, which is highly conserved and ubiquitously expressed. Numerous data suggest it functions in cellular adhesion. For example, APP binds components of the extracellular matrix to propagate intracellular signaling responses. In order to investigate adhesion-related changes in inflamed vasculature, brains from apolipoprotein E(-/-) (apoE(-/-)) mice were examined for changes related to APP then compared to human Alzheimer's disease (AD) brains. Cerebrovasculature from mouse apoE(-)/(-) and human AD brains revealed strong immunoreactivity for APP, APP phosphorylated at tyrosine residue 682 (pAPP) and Aβ. Further, Western blot analyses from mouse apoE(-/-) and AD brains showed statistically higher protein levels of APP, pAPP and increased APP association with the tyrosine kinase, Src. Lastly, utilizing a modified Stamper-Woodruff adhesion assay, we demonstrated that adhesion of monocytic cells to apoE(-/-) and AD brain endothelium is partially APP dependent. These data suggest that endothelial APP function coupled with increased Aβ production are involved in the vascular dysfunction associated with atherosclerosis and AD.
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Affiliation(s)
- Susan A Austin
- Department of Pharmacology, Physiology & Therapeutics, University of North Dakota, School of Medicine and Health Sciences, 504 Hamline St., Room 116, Grand Forks, ND 58203, United States
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30
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Lee YH, Tharp WG, Maple RL, Nair S, Permana PA, Pratley RE. Amyloid precursor protein expression is upregulated in adipocytes in obesity. Obesity (Silver Spring) 2008; 16:1493-500. [PMID: 18483477 DOI: 10.1038/oby.2008.267] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The aim of this study was to determine whether amyloid precursor protein (APP) is expressed in human adipose tissue, dysregulated in obesity, and related to insulin resistance and inflammation. APP expression was examined by microarray expression profiling of subcutaneous abdominal adipocytes (SAC) and cultured preadipocytes from obese and nonobese subjects. Quantitative real-time PCR (QPCR) was performed to confirm differences in APP expression in SAC and to compare APP expression levels in adipose tissue, adipocytes, and stromal vascular cells (SVCs) from subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) specimens. Adipose tissue samples were also examined by western blot and immunofluorescence confocal microscopy. Microarray studies demonstrated that APP mRNA expression levels were higher in SAC (approximately 2.5-fold) and preadipocytes (approximately 1.4) from obese subjects. Real-time PCR confirmed increased APP expression in SAC in a separate group of obese compared with nonobese subjects (P=0.02). APP expression correlated to in vivo indices of insulin resistance independently of BMI and with the expression of proinflammatory genes, such as monocyte chemoattractant protein-1 (MCP-1) (R=0.62, P=0.004), macrophage inflammatory protein-1alpha (MIP-1alpha) (R=0.60, P=0.005), and interleukin-6 (IL-6) (R=0.71, P=0.0005). Full-length APP protein was detected in adipocytes by western blotting and APP and its cleavage peptides, Abeta40 and Abeta42, were observed in SAT and VAT by immunofluorescence confocal microscopy. In summary, APP is highly expressed in adipose tissue, upregulated in obesity, and expression levels correlate with insulin resistance and adipocyte cytokine expression levels. These data suggest a possible role for APP and/or Abeta in the development of obesity-related insulin resistance and adipose tissue inflammation.
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Affiliation(s)
- Yong-Ho Lee
- Diabetes and Metabolism Translational Medicine Unit, University of Vermont College of Medicine, Burlington, Vermont, USA
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31
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Tsuda M, Ueno H, Kataoka A, Tozaki-Saitoh H, Inoue K. Activation of dorsal horn microglia contributes to diabetes-induced tactile allodynia via extracellular signal-regulated protein kinase signaling. Glia 2008; 56:378-86. [PMID: 18186080 DOI: 10.1002/glia.20623] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Painful neuropathy is one of the most common complications of diabetes, one hallmark of which is tactile allodynia (pain hypersensitivity to innocuous stimulation). The underlying mechanisms of tactile allodynia are, however, poorly understood. Emerging evidence indicates that, following nerve injury, activated microglia in the spinal cord play a crucial role in tactile allodynia. However, it remains unknown whether spinal microglia are activated under diabetic conditions and whether they contribute to diabetes-induced tactile allodynia. In the present study, using streptozotocin (STZ)-induced diabetic rats that displayed tactile allodynia, we found several morphological changes of activated microglia in the dorsal horn. These included increases in Iba1 and OX-42 labeling (markers of microglia), hypertrophic morphology, the thickness and the retraction of processes, and in the number of activated microglia cells. Furthermore, in the dorsal horn of STZ diabetic rats, extracellular signal-regulated protein kinase (ERK) and an upstream kinase, Src-family kinase (SFK), both of which are implicated in microglial functions, were activated exclusively in microglia. Moreover, inhibition of ERK phosphorylation in the dorsal horn by intrathecal administration of U0126, an inhibitor of ERK activation, produced a striking alleviation of existing, long-term tactile allodynia of diabetic rats. We also found that a single administration of U0126 reduced the expression of allodynia. Together, these results suggest that activated dorsal horn microglia may be a crucial component of diabetes-induced tactile allodynia, mediated, in part, by the ERK signaling pathway. Thus, inhibiting microglia activation in the dorsal horn may represent a therapeutic strategy for treating diabetic tactile allodynia.
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Affiliation(s)
- Makoto Tsuda
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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32
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Schmidt J, Barthel K, Wrede A, Salajegheh M, Bähr M, Dalakas MC. Interrelation of inflammation and APP in sIBM: IL-1 beta induces accumulation of beta-amyloid in skeletal muscle. ACTA ACUST UNITED AC 2008; 131:1228-40. [PMID: 18420712 PMCID: PMC2367696 DOI: 10.1093/brain/awn053] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Distinct interrelationships between inflammation and beta-amyloid-associated degeneration, the two major hallmarks of the skeletal muscle pathology in sporadic inclusion body myositis (sIBM), have remained elusive. Expression of markers relevant for these pathomechanisms were analysed in biopsies of sIBM, polymyositis (PM), dermatomyositis (DM), dystrophic and non-myopathic muscle as controls, and cultured human myotubes. By quantitative PCR, a higher upregulation was noted for the mRNA-expression of CXCL-9, CCL-3, CCL-4, IFN-gamma, TNF-alpha and IL-1 beta in sIBM muscle compared to PM, DM and controls. All inflammatory myopathies displayed overexpression of degeneration-associated markers, yet only in sIBM, expression of the mRNA of amyloid precursor protein (APP) significantly and consistently correlated with inflammation in the muscle and mRNA-levels of chemokines and IFN-gamma. Only in sIBM, immunohistochemical analysis revealed that inflammatory mediators including IL-1 beta co-localized to beta-amyloid depositions within myofibres. In human myotubes, exposure to IL-1 beta caused upregulation of APP with subsequent intracellular aggregation of beta-amyloid. Our data suggest that, in sIBM muscle, production of high amounts of pro-inflammatory mediators specifically induces beta-amyloid-associated degeneration. The observations may help to design targeted treatment strategies for chronic inflammatory disorders of the skeletal muscle.
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Affiliation(s)
- Jens Schmidt
- Neuromuscular Diseases Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA.
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33
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Copper binding to the Alzheimer's disease amyloid precursor protein. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2007; 37:269-79. [PMID: 18030462 PMCID: PMC2921068 DOI: 10.1007/s00249-007-0234-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2007] [Revised: 10/24/2007] [Accepted: 10/26/2007] [Indexed: 12/25/2022]
Abstract
Alzheimer’s disease is the fourth biggest killer in developed countries. Amyloid precursor protein (APP) plays a central role in the development of the disease, through the generation of a peptide called Aβ by proteolysis of the precursor protein. APP can function as a metalloprotein and modulate copper transport via its extracellular copper binding domain (CuBD). Copper binding to this domain has been shown to reduce Aβ levels and hence a molecular understanding of the interaction between metal and protein could lead to the development of novel therapeutics to treat the disease. We have recently determined the three-dimensional structures of apo and copper bound forms of CuBD. The structures provide a mechanism by which CuBD could readily transfer copper ions to other proteins. Importantly, the lack of significant conformational changes to CuBD on copper binding suggests a model in which copper binding affects the dimerisation state of APP leading to reduction in Aβ production. We thus predict that disruption of APP dimers may be a novel therapeutic approach to treat Alzheimer’s disease.
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34
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Rusu P, Jansen A, Soba P, Kirsch J, Löwer A, Merdes G, Kuan YH, Jung A, Beyreuther K, Kjaerulff O, Kins S. Axonal accumulation of synaptic markers in APP transgenic Drosophila depends on the NPTY motif and is paralleled by defects in synaptic plasticity. Eur J Neurosci 2007; 25:1079-86. [PMID: 17331204 DOI: 10.1111/j.1460-9568.2007.05341.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease (AD) is characterized by neurofibrillary tangles and extracellular plaques, which consist mainly of beta-amyloid derived from the beta-amyloid precursor protein (APP). An additional feature of AD is axonopathy, which might contribute to impairment of cognitive functions. Specifically, axonal transport defects have been reported in AD animal models, including mice and flies that overexpress APP and tau. Here we demonstrate that the APP-induced traffic jam of vesicles in peripheral nerves of Drosophila melanogaster larvae depends on the four residues NPTY motif in the APP intracellular domain. Furthermore, heterologous expression of Fe65 and JIP1b, scaffolding proteins interacting with the NPTY motif, also perturb axonal transport. Together, these data indicate that JIP1b or Fe65 may be involved in the APP-induced axonal transport defect. Moreover, we have characterized neurotransmission at the neuromuscular junction in transgenic larvae that express human APP. Consistent with the observation that these larvae do not show any obvious movement deficits, we found no changes in basal synaptic transmission. However, short-term synaptic plasticity was affected by overexpression of APP. Together, our results show that overexpression of APP induces partial stalling of axonal transport vesicles, paralleled by abnormalities in synaptic plasticity, which may provide a functional link to the deterioration of cognitive functions observed in AD.
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Affiliation(s)
- Patricia Rusu
- Zentrum für Molekulare Biologie (ZMBH), Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
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35
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Kong GKW, Adams JJ, Harris HH, Boas JF, Curtain CC, Galatis D, Masters CL, Barnham KJ, McKinstry WJ, Cappai R, Parker MW. Structural Studies of the Alzheimer’s Amyloid Precursor Protein Copper-binding Domain Reveal How it Binds Copper Ions. J Mol Biol 2007; 367:148-61. [PMID: 17239395 DOI: 10.1016/j.jmb.2006.12.041] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2006] [Revised: 12/11/2006] [Accepted: 12/15/2006] [Indexed: 11/30/2022]
Abstract
Alzheimer's disease (AD) is the major cause of dementia. Amyloid beta peptide (Abeta), generated by proteolytic cleavage of the amyloid precursor protein (APP), is central to AD pathogenesis. APP can function as a metalloprotein and modulate copper (Cu) transport, presumably via its extracellular Cu-binding domain (CuBD). Cu binding to the CuBD reduces Abeta levels, suggesting that a Cu mimetic may have therapeutic potential. We describe here the atomic structures of apo CuBD from three crystal forms and found they have identical Cu-binding sites despite the different crystal lattices. The structure of Cu(2+)-bound CuBD reveals that the metal ligands are His147, His151, Tyr168 and two water molecules, which are arranged in a square pyramidal geometry. The site resembles a Type 2 non-blue Cu center and is supported by electron paramagnetic resonance and extended X-ray absorption fine structure studies. A previous study suggested that Met170 might be a ligand but we suggest that this residue plays a critical role as an electron donor in CuBDs ability to reduce Cu ions. The structure of Cu(+)-bound CuBD is almost identical to the Cu(2+)-bound structure except for the loss of one of the water ligands. The geometry of the site is unfavorable for Cu(+), thus providing a mechanism by which CuBD could readily transfer Cu ions to other proteins.
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Affiliation(s)
- Geoffrey K-W Kong
- Biota Structural Biology Laboratory, St. Vincent's Institute, 9 Princes Street, Fitzroy, Victoria 3065, Australia
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36
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Tsuda M, Tozaki-Saitoh H, Masuda T, Toyomitsu E, Tezuka T, Yamamoto T, Inoue K. Lyn tyrosine kinase is required for P2X4 receptor upregulation and neuropathic pain after peripheral nerve injury. Glia 2007; 56:50-8. [DOI: 10.1002/glia.20591] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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37
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Austin SA, Floden AM, Murphy EJ, Combs CK. Alpha-synuclein expression modulates microglial activation phenotype. J Neurosci 2006; 26:10558-63. [PMID: 17035541 PMCID: PMC6674709 DOI: 10.1523/jneurosci.1799-06.2006] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Recent Parkinson's disease research has focused on understanding the function of the cytosolic protein, alpha-synuclein, and its contribution to disease mechanisms. Within neurons, alpha-synuclein is hypothesized to have a role in regulating synaptic plasticity, vesicle release, and trafficking. In contrast, glial-expressed alpha-synuclein remains poorly described. Here, we examine the consequence of a loss of alpha-synuclein expression on microglial activation. Using a postnatal brain-derived culture system, we defined the phenotype of microglia from wild-type and knock-out alpha-synuclein mice (Scna-/-). Scna-/- microglia displayed a basally increased reactive phenotype compared with the wild-type cells and an exacerbated reactive phenotype after stimulation. They also exhibited dramatic morphologic differences compared with wild-type, presenting as large, ramified cells filled with vacuole-like structures. This corresponded with increased protein levels of activation markers, CD68 and beta1 integrin, in the Scna-/- cells. More importantly, Scna-/- microglia, after stimulation, secreted elevated levels of proinflammatory cytokines, TNFalpha (tumor necrosis factor alpha) and IL-6 (interleukin-6), compared with wild type. However, despite the reactive phenotype, Scna-/- cells had impaired phagocytic ability. We demonstrate for the first time that alpha-synuclein plays a critical role in modulating microglial activation state. We suggest that altered microglial alpha-synuclein expression will affect their phenotype as has already been demonstrated in neurons. This has direct ramifications for the contribution of microglia to the pathophysiology of disease, particularly in familial cases linked to altered alpha-synuclein expression.
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Affiliation(s)
- Susan A. Austin
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9037
| | - Angela M. Floden
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9037
| | - Eric J. Murphy
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9037
| | - Colin K. Combs
- Department of Pharmacology, Physiology, and Therapeutics, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9037
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Kubatova A, Murphy TC, Combs C, Picklo MJ. Astrocytic biotransformation of trans-4-hydroxy-2-nonenal is dose-dependent. Chem Res Toxicol 2006; 19:844-51. [PMID: 16780364 DOI: 10.1021/tx0600393] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Elevated levels of trans-4-hydroxy-2-nonenal (HNE) are observed in brain tissues in patients with neurodegenerative diseases. Although astrocytes are known to play a crucial role in regulating and supporting neuronal processes, their capacity to detoxify HNE is unknown. In this work, we examined the extent to which HNE undergoes phase I and phase II metabolism in astrocytes. Murine astrocytes were exposed to three different concentrations of HNE. The loss of HNE was approximately 90%, 80%, and 70% for 1, 5, and 15 microM HNE, respectively, following a 10 min incubation. The expected metabolites trans-4-hydroxy-2-nonenoic acid (HNEAcid), (4-hydroxynonanal-3-yl)glutathione (GSHNE), and (1,4-dihydroxynonane-3-yl)glutathione (GSDHN) accounted for 90% of HNE lost at 1 microM HNE. However, when astrocytes were exposed to 5 and 15 microM HNE, those metabolites accounted only for 50% and 17%, respectively. Binding to macromolecules accounted for only 5-10% of HNE loss. Furthermore, depletion of GSH content had only a small effect on HNE metabolism without elevating HNE oxidation and suggests that other unidentified metabolic pathways are functioning. We identified two novel metabolites of HNE, gamma-nonalactone and the potent pyrrole forming compound, 4-oxo-nonanal (ONA). Occurrence of 1,4-dihydroxynonene was observed as well. These data suggest that the biotransformation of HNE yields products with differing or enhanced toxicity, as well as nontoxic products.
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Affiliation(s)
- Alena Kubatova
- Department of Chemistry, University of North Dakota, Grand Forks, 58202, USA
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39
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Sondag CM, Combs CK. Amyloid precursor protein cross-linking stimulates beta amyloid production and pro-inflammatory cytokine release in monocytic lineage cells. J Neurochem 2006; 97:449-61. [PMID: 16539666 DOI: 10.1111/j.1471-4159.2006.03759.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Beta amyloid peptide-containing neuritic plaques are a defining feature of Alzheimer's disease pathology. Beta amyloid are 38-43 residue peptides derived by proteolytic cleavage of amyloid precursor protein. Although much attention has focused on the proteolytic events leading to beta amyloid generation, the function of amyloid precursor protein remains poorly described. Previously, we reported that amyloid precursor protein functions as a pro-inflammatory receptor on monocytic lineage cells and defined a role for amyloid precursor protein in adhesion by demonstrating that beta(1) integrin-mediated pro-inflammatory activation of monocytes is amyloid precursor protein dependent. We demonstrated that antibody-induced cross-linking of amyloid precursor protein in human THP-1 monocytes and primary mouse microglia stimulates a tyrosine kinase-based pro-inflammatory signaling response leading to acquisition of a reactive phenotype. Here, we have identified pro-inflammatory mediators released upon amyloid precursor protein-dependent activation of monocytes and microglia. We show that amyloid precursor protein cross-linking stimulated tyrosine kinase-dependent increases in pro-inflammatory cytokine release and a tyrosine kinase-independent increase in beta amyloid 1-42 generation. These data provide much needed insight into the function of amyloid precursor protein and provide potential therapeutic targets to limit inflammatory changes associated with the progression of Alzheimer's disease.
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Affiliation(s)
- C M Sondag
- Department Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, 58202, USA
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40
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Lotz M, Ebert S, Esselmann H, Iliev AI, Prinz M, Wiazewicz N, Wiltfang J, Gerber J, Nau R. Amyloid beta peptide 1-40 enhances the action of Toll-like receptor-2 and -4 agonists but antagonizes Toll-like receptor-9-induced inflammation in primary mouse microglial cell cultures. J Neurochem 2005; 94:289-98. [PMID: 15998280 DOI: 10.1111/j.1471-4159.2005.03188.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The interaction of endogenous and exogenous stimulators of innate immunity was examined in primary cultures of mouse microglial cells and macrophages after application of defined Toll-like receptor (TLR) agonists [lipopolysaccharide (LPS) (TLR4), the synthetic lipopeptide Pam3Cys-Ser-Lys4 (Pam3Cys) (TLR2) and single-stranded unmethylated CpG-DNA (CpG) (TLR9)] alone and in combination with amyloid beta peptide (Abeta) 1-40. Abeta1-40 stimulated microglial cells and macrophages primed by interferon-gamma in a dose-dependent manner. Co-administration of Abeta1-40 with LPS or Pam3Cys led to an additive release of nitric oxide (NO) and tumour necrosis factor alpha (TNF-alpha). This may be one reason for the clinical deterioration frequently observed in patients with Alzheimer's disease during infections. In contrast, co-application of Abeta1-40 with CpG led to a substantial decrease of NO and TNF-alpha release compared with stimulation with CpG alone. Abeta1-40 and CpG did not co-localize within the same subcellular compartment, making a direct physicochemical interaction as the cause of the observed antagonism very unlikely. This suggests that not all TLR agonists enhance the stimulatory effect of A beta on innate immunity.
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Affiliation(s)
- Miriam Lotz
- Department of Neurology, Georg-August-University, Göttingen, Germany
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41
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Mbebi C, González de Aguilar JL, Sée V, Dupuis L, Frossard N, Mercken L, Pradier L, Larmet Y, Loeffler JP. Antibody-bound β-amyloid precursor protein stimulates the production of tumor necrosis factor-α and monocyte chemoattractant protein-1 by cortical neurons. Neurobiol Dis 2005; 19:129-41. [PMID: 15837568 DOI: 10.1016/j.nbd.2004.11.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2004] [Revised: 11/23/2004] [Accepted: 11/24/2004] [Indexed: 10/25/2022] Open
Abstract
Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by the accumulation of extracellular depositions of fibrillar beta-amyloid (A beta), which is derived from the alternative processing of beta-amyloid precursor protein (APP). Although APP is thought to function as a cell surface receptor, its mode of action still remains elusive. In this study, we found that the culture medium derived from cortical neurons treated with an anti-APP antibody triggers the death of naive neurons. Biochemical and immunocytochemical analyses revealed the presence, both in the conditioned medium and in neurons, of increased levels of tumor necrosis factor-alpha and monocyte chemoattractant protein-1. Furthermore, the expression of these proinflammatory mediators occurred through a c-Jun N-terminal protein kinase/c-Jun-dependent mechanism. Taken together, our findings provide evidence for a novel mechanism whereby neuronal APP in its full-length configuration induces neuronal death. Such a mechanism might be relevant to neuroinflammatory processes as those observed in AD.
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Affiliation(s)
- Corinne Mbebi
- Laboratoire de Signalisations Moléculaires et Neurodégénérescence, INSERM, U692, Université Louis Pasteur, Faculté de Médecine, 11, rue Humann, 67085 Strasbourg cedex, France
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Vehmas A, Lieu J, Pardo CA, McArthur JC, Gartner S. Amyloid precursor protein expression in circulating monocytes and brain macrophages from patients with HIV-associated cognitive impairment. J Neuroimmunol 2005; 157:99-110. [PMID: 15579286 DOI: 10.1016/j.jneuroim.2004.08.035] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2004] [Indexed: 11/30/2022]
Abstract
We examined amyloid precursor protein (APP) surface expression on circulating leukocytes and in brain tissues from normal individuals and HIV+ subjects with cognitive impairment. Most monocytes, and a subset of B-lymphocytes, expressed APP, while T-lymphocytes, granulocytes, and natural killer (NK) cells did not. CD14bright/CD16+ monocytes expressed the highest levels, and CD14dim/CD16+ cells were negative, suggesting a relationship with activation. Higher APP+ monocyte levels correlated with increased numbers of CD16+ monocytes, but not with the degree of cognitive impairment. Treatment of monocytes with M-CSF, but not LPS, upregulated APP expression. In the brain, APP appeared as axonal immunoreactivity and diffuse plaques, and APP+ perivascular macrophages were seen in cases with severe dementia. APP may facilitate monocyte entry into the brain.
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Affiliation(s)
- Ari Vehmas
- Department of Neurology, Johns Hopkins Hospital, 600 North Wolfe Street, Baltimore, MD 21287, USA
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Koistinaho M, Koistinaho J. Interactions between Alzheimer's disease and cerebral ischemia--focus on inflammation. ACTA ACUST UNITED AC 2005; 48:240-50. [PMID: 15850663 DOI: 10.1016/j.brainresrev.2004.12.014] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2004] [Accepted: 12/09/2004] [Indexed: 12/27/2022]
Abstract
Progressive memory impairment, beta-amyloid (Abeta) plaques associated with local inflammation, neurofibrillary tangles, and loss of neurons in selective brain areas are hallmarks of Alzheimer's disease (AD). Although beta-amyloid precursor protein (APP) and Abeta have a central role in the etiology of AD, it is not clear which forms of APP or Abeta are responsible for the neuronal vulnerability in AD brain. Brain ischemia, another cause of dementia in the elderly, has recently been recognized to contribute to the pathogenesis of AD and individuals with severe cognitive decline and possibly underlying AD are at increased risk for ischemic events in the brain. Moreover, the epsilon4 allele of apolipoprotein E (ApoE) is a risk factor for both AD and poor outcome following brain ischemia and hemorrhage. Several factors and molecular mechanisms that lower the threshold of neuronal death in models of AD have recently been described. Among these neuroinflammation seems to play an important role. The development and maturation of both AD neuropathology and ischemic lesions in the central nervous system are characterized by activation of glial cells and upregulation of inflammatory mediators. Indeed, anti-inflammatory approaches have proven to be beneficial in the prevention and treatment of AD-like neuropathology and ischemic injuries in vivo. This review summarizes some of the findings suggesting that neuronal overexpression of human APP renders the brain more vulnerable to ischemic injury and describes the factors that are involved in increased neuronal susceptibility to ischemic stroke.
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Affiliation(s)
- Milla Koistinaho
- A.I. Virtanen Institute for Molecular Sciences, University of Kuopio, Finland.
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