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Abstract
Neurodegenerative diseases have a variety of different genes contributing to their underlying pathology. Unfortunately, for many of these diseases it is not clear how changes in gene expression affect pathology. Transcriptome analysis of neurodegenerative diseases using ribonucleic acid sequencing (RNA Seq) and real time quantitative polymerase chain reaction (RT-qPCR) provides for a platform to allow investigators to determine the contribution of various genes to the disease phenotype. In Alzheimer's disease (AD) there are several candidate genes reported that may be associated with the underlying pathology and are, in addition, alternatively spliced. Thus, AD is an ideal disease to examine how alternative splicing may affect pathology. In this context, genes of particular interest to AD pathology include the amyloid precursor protein (APP), TAU, and apolipoprotein E (APOE). Here, we review the evidence of alternative splicing of these genes in normal and AD patients, and recent therapeutic approaches to control splicing.
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Affiliation(s)
- Julia E Love
- Department of Biological Sciences, Science Building, Boise State University, USA
| | - Eric J Hayden
- Department of Biological Sciences, Science Building, Boise State University, USA
| | - Troy T Rohn
- Department of Biological Sciences, Science Building, Boise State University, USA
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202
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Edgar JR, Willén K, Gouras GK, Futter CE. ESCRTs regulate amyloid precursor protein sorting in multivesicular bodies and intracellular amyloid-β accumulation. J Cell Sci 2015; 128:2520-8. [PMID: 26002056 PMCID: PMC4510853 DOI: 10.1242/jcs.170233] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 05/21/2015] [Indexed: 01/26/2023] Open
Abstract
Intracellular amyloid-β (Aβ) accumulation is a key feature of early Alzheimer's disease and precedes the appearance of Aβ in extracellular plaques. Aβ is generated through proteolytic processing of amyloid precursor protein (APP), but the intracellular site of Aβ production is unclear. APP has been localized to multivesicular bodies (MVBs) where sorting of APP onto intraluminal vesicles (ILVs) could promote amyloidogenic processing, or reduce Aβ production or accumulation by sorting APP and processing products to lysosomes for degradation. Here, we show that APP localizes to the ILVs of a subset of MVBs that also traffic EGF receptor (EGFR), and that it is delivered to lysosomes for degradation. Depletion of the endosomal sorting complexes required for transport (ESCRT) components, Hrs (also known as Hgs) or Tsg101, inhibited targeting of APP to ILVs and the subsequent delivery to lysosomes, and led to increased intracellular Aβ accumulation. This was accompanied by dramatically decreased Aβ secretion. Thus, the early ESCRT machinery has a dual role in limiting intracellular Aβ accumulation through targeting of APP and processing products to the lysosome for degradation, and promoting Aβ secretion.
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Affiliation(s)
- James R Edgar
- Department of Cell Biology, UCL Institute of Ophthalmology, London EC1 V9EL, UK Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Katarina Willén
- Department of Experimental Medical Science, Lund University, Lund 22184, Sweden
| | - Gunnar K Gouras
- Department of Experimental Medical Science, Lund University, Lund 22184, Sweden
| | - Clare E Futter
- Department of Cell Biology, UCL Institute of Ophthalmology, London EC1 V9EL, UK
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203
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Christianson MG, Lo DC. Differential roles of Aβ processing in hypoxia-induced axonal damage. Neurobiol Dis 2015; 77:94-105. [PMID: 25771168 DOI: 10.1016/j.nbd.2015.02.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 01/28/2015] [Accepted: 02/11/2015] [Indexed: 11/25/2022] Open
Abstract
Axonopathy is a common and early phase in neurodegenerative and traumatic CNS diseases. Recent work suggests that amyloid β (Aβ) produced from amyloid precursor protein (APP) may be a critical downstream mediator of CNS axonopathy in CNS diseases, particularly those associated with hypoxia. We critically tested this hypothesis in an adult retinal explant system that preserves the three-dimensional organization of the retina while permitting direct imaging of two cardinal features of early-stage axonopathy: axonal structural integrity and axonal transport capacity. Using this system, we found via pharmacological inhibition and genetic deletion of APP that production of Aβ is a necessary step in structural compromise of retinal ganglion cell (RGC) axons induced by the disease-relevant stressor hypoxia. However, identical blockade of Aβ production was not sufficient to protect axons from associated hypoxia-induced reduction in axonal transport. Thus, Aβ mediates distinct facets of hypoxia-induced axonopathy and may represent a functionally selective pharmacological target for therapies directed against early-stage axonopathy in CNS diseases.
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Affiliation(s)
- Melissa G Christianson
- Center for Drug Discovery and Department of Neurobiology, Duke University Medical Center, Durham, NC, USA.
| | - Donald C Lo
- Center for Drug Discovery and Department of Neurobiology, Duke University Medical Center, Durham, NC, USA
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204
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Blake MR, Holbrook SD, Kotwica-Rolinska J, Chow ES, Kretzschmar D, Giebultowicz JM. Manipulations of amyloid precursor protein cleavage disrupt the circadian clock in aging Drosophila. Neurobiol Dis 2015; 77:117-26. [PMID: 25766673 DOI: 10.1016/j.nbd.2015.02.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 01/14/2015] [Accepted: 02/15/2015] [Indexed: 11/30/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease characterized by severe cognitive deterioration. While causes of AD pathology are debated, a large body of evidence suggests that increased cleavage of Amyloid Precursor Protein (APP) producing the neurotoxic Amyloid-β (Aβ) peptide plays a fundamental role in AD pathogenesis. One of the detrimental behavioral symptoms commonly associated with AD is the fragmentation of sleep-activity cycles with increased nighttime activity and daytime naps in humans. Sleep-activity cycles, as well as physiological and cellular rhythms, which may be important for neuronal homeostasis, are generated by a molecular system known as the circadian clock. Links between AD and the circadian system are increasingly evident but not well understood. Here we examined whether genetic manipulations of APP-like (APPL) protein cleavage in Drosophila melanogaster affect rest-activity rhythms and core circadian clock function in this model organism. We show that the increased β-cleavage of endogenous APPL by the β-secretase (dBACE) severely disrupts circadian behavior and leads to reduced expression of clock protein PER in central clock neurons of aging flies. Our data suggest that behavioral rhythm disruption is not a product of APPL-derived Aβ production but rather may be caused by a mechanism common to both α and β-cleavage pathways. Specifically, we show that increased production of the endogenous Drosophila Amyloid Intracellular Domain (dAICD) caused disruption of circadian rest-activity rhythms, while flies overexpressing endogenous APPL maintained stronger circadian rhythms during aging. In summary, our study offers a novel entry point toward understanding the mechanism of circadian rhythm disruption in Alzheimer's disease.
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Affiliation(s)
- Matthew R Blake
- Department of Integrative Biology, Oregon State University, Corvallis, OR 97331, USA
| | - Scott D Holbrook
- Oregon Institute of Occupational Health Sciences, Oregon Health and Science University, Portland, OR 97239, USA
| | | | - Eileen S Chow
- Department of Integrative Biology, Oregon State University, Corvallis, OR 97331, USA
| | - Doris Kretzschmar
- Oregon Institute of Occupational Health Sciences, Oregon Health and Science University, Portland, OR 97239, USA
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205
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Yu Y, Li Y, Zhang Y. Screening of APP interaction proteins by DUALmembrane yeast two-hybrid system. Int J Clin Exp Pathol 2015; 8:2802-2808. [PMID: 26045787 PMCID: PMC4440096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Accepted: 02/26/2015] [Indexed: 06/04/2023]
Abstract
Alzheimer's disease (AD) is one of the most common forms of neurodegenerative disease. There is a growing interest in the amyloid precursor protein (APP) over the years due to its involvement in AD. Besides its role in pathological mechanisms of AD, APP participates in many signaling pathways as well. APP functions through protein-protein interactions, and in this report staufen 1 (STAU1) is demonstrated to have interaction with APP, using yeast two-hybrid screening and co-immunoprecipitation in mammalian system. STAU1 belongs to the double-stranded RNA binding protein family and can mediate mRNA degradation in mammalian system, implicating that APP may be involved in the regulation of mRNA as well.
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Affiliation(s)
- You Yu
- State Key Laboratory of Biomembrane and Membrane Biotechnology, College of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University Beijing 100871, China
| | - Yinan Li
- State Key Laboratory of Biomembrane and Membrane Biotechnology, College of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University Beijing 100871, China
| | - Yan Zhang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, College of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University Beijing 100871, China
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206
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Deng Z, Fu H, Xiao Y, Zhang B, Sun G, Wei Q, Ai B, Hu Q. Effects of selenium on lead-induced alterations in Aβ production and Bcl-2 family proteins. Environ Toxicol Pharmacol 2015; 39:221-228. [PMID: 25528413 DOI: 10.1016/j.etap.2014.11.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 11/20/2014] [Indexed: 06/04/2023]
Abstract
Previous studies in humans and animals have suggested that lead (Pb) may increase the expression of amyloid precursor protein (APP) and accumulation of amyloid β protein (Aβ). Our previous studies have revealed that selenium (Se) can partially improve memory deficits induced by Pb exposure. In this study we sought to investigate the effect of Pb and Se on the endogenous expression of APP, Aβ40 and Bcl-2 family proteins. In vitro, the protein levels of APP and Aβ significantly decreased in SH-SY5Y and PC12 cells co-incubated with Pb-acetate and selenomethionine (SeMet) for 48h, compared with cells treated with Pb-acetate alone. Furthermore, these reductions induced by Se appeared to be concentration-dependent. In Wistar rats, we observed that the mRNA and protein levels of APP, the protein level of Bax, and the ratio of Bax/Bcl-2 protein significantly increased after Pb treatment at embryonic stage and in neonates. These increases were significantly reversed by the treatment of Se. Taken together, our results suggest that Se can attenuate the alterations in APP expression and Aβ production as well as Bcl-2 family proteins induced by lead exposure in cells and in animals.
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Affiliation(s)
- Zhiqiang Deng
- Department of Preventive Medicine, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China; Nanchang Center for Disease Control and Prevention, Nanchang 330038, China
| | - Hongjun Fu
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Yongmei Xiao
- Department of Preventive Medicine, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China
| | - Bo Zhang
- Department of Preventive Medicine, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China
| | - Guangshun Sun
- Department of Preventive Medicine, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China
| | - Qing Wei
- Department of Preventive Medicine, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China
| | - Baomin Ai
- Department of Preventive Medicine, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China
| | - Qiansheng Hu
- Department of Preventive Medicine, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China.
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207
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Hartley D, Blumenthal T, Carrillo M, DiPaolo G, Esralew L, Gardiner K, Granholm AC, Iqbal K, Krams M, Lemere C, Lott I, Mobley W, Ness S, Nixon R, Potter H, Reeves R, Sabbagh M, Silverman W, Tycko B, Whitten M, Wisniewski T. Down syndrome and Alzheimer's disease: Common pathways, common goals. Alzheimers Dement 2014; 11:700-9. [PMID: 25510383 DOI: 10.1016/j.jalz.2014.10.007] [Citation(s) in RCA: 180] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Revised: 08/26/2014] [Accepted: 10/02/2014] [Indexed: 12/17/2022]
Abstract
In the United States, estimates indicate there are between 250,000 and 400,000 individuals with Down syndrome (DS), and nearly all will develop Alzheimer's disease (AD) pathology starting in their 30s. With the current lifespan being 55 to 60 years, approximately 70% will develop dementia, and if their life expectancy continues to increase, the number of individuals developing AD will concomitantly increase. Pathogenic and mechanistic links between DS and Alzheimer's prompted the Alzheimer's Association to partner with the Linda Crnic Institute for Down Syndrome and the Global Down Syndrome Foundation at a workshop of AD and DS experts to discuss similarities and differences, challenges, and future directions for this field. The workshop articulated a set of research priorities: (1) target identification and drug development, (2) clinical and pathological staging, (3) cognitive assessment and clinical trials, and (4) partnerships and collaborations with the ultimate goal to deliver effective disease-modifying treatments.
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Affiliation(s)
- Dean Hartley
- Medical and Scientific Relations, Alzheimer's Association, Chicago, IL, USA.
| | - Thomas Blumenthal
- Linda Crnic Institute for Down Syndrome, University of Colorado, Aurora, CO, USA; Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO, USA
| | - Maria Carrillo
- Medical and Scientific Relations, Alzheimer's Association, Chicago, IL, USA
| | - Gilbert DiPaolo
- Department of Pathology and Cell Biology, Columbia University Medical Center and The Taub Institute for Research on Alzheimer's Disease and The Aging Brain, New York, NY, USA
| | - Lucille Esralew
- Department of Behavioral Health, Trinitas Regional Medical Center, Elizabeth, NJ, USA
| | - Katheleen Gardiner
- Linda Crnic Institute for Down Syndrome, University of Colorado, Aurora, CO, USA; Department of Pediatrics, University of Colorado, Denver, CO, USA
| | - Ann-Charlotte Granholm
- Department of Neuroscience and the Center on Aging, Medical University of South Carolina, Columbia, SC, USA
| | - Khalid Iqbal
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, New York, NY, USA
| | | | - Cynthia Lemere
- Department of Neurology and the Anne Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ira Lott
- Department of Pediatrics, University of California, Irvine, CA, USA
| | - William Mobley
- Department of Neurosciences, University of California, San Diego, CA, USA
| | - Seth Ness
- Janssen Research & Development, Raritan, NJ, USA
| | - Ralph Nixon
- Department of Psychiatry and Cell Biology, New York University, Langone Medical Center, New York, NY, USA
| | - Huntington Potter
- Linda Crnic Institute for Down Syndrome, University of Colorado, Aurora, CO, USA; Department of Neurology, University of Colorado, Denver, CO, USA
| | - Roger Reeves
- Department of Physiology, McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Marwan Sabbagh
- Banner Sun Health Research Institute, Banner Health, Sun City, AZ, USA
| | - Wayne Silverman
- Department of Behavioral Psychology, Kennedy Krieger Institute, Baltimore, MD, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Benjamin Tycko
- Department of Pathology and Cell Biology, Columbia University Medical Center and The Taub Institute for Research on Alzheimer's Disease and The Aging Brain, New York, NY, USA
| | | | - Thomas Wisniewski
- Department of Neurology, Pathology, and Psychiatry, New York University, Langone Medical Center, New York, NY, USA
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208
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Erickson CA, Ray B, Maloney B, Wink LK, Bowers K, Schaefer TL, McDougle CJ, Sokol DK, Lahiri DK. Impact of acamprosate on plasma amyloid-β precursor protein in youth: a pilot analysis in fragile X syndrome-associated and idiopathic autism spectrum disorder suggests a pharmacodynamic protein marker. J Psychiatr Res 2014; 59:220-8. [PMID: 25300441 PMCID: PMC4253657 DOI: 10.1016/j.jpsychires.2014.07.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 07/09/2014] [Accepted: 07/14/2014] [Indexed: 12/20/2022]
Abstract
BACKGROUND Understanding of the pathophysiology of autism spectrum disorder (ASD) remains limited. Brain overgrowth has been hypothesized to be associated with the development of ASD. A derivative of amyloid-β precursor protein (APP), secreted APPα (sAPPα), has neuroproliferative effects and has been shown to be elevated in the plasma of persons with ASD compared to control subjects. Reduction in sAPPα holds promise as a novel molecular target of treatment in ASD. Research into the neurochemistry of ASD has repeatedly implicated excessive glutamatergic and deficient GABAergic neurotransmission in the disorder. With this in mind, acamprosate, a novel modulator of glutamate and GABA function, has been studied in ASD. No data is available on the impact of glutamate or GABA modulation on sAPPα function. METHODS Plasma APP derivative levels pre- and post-treatment with acamprosate were determined in two pilot studies involving youth with idiopathic and fragile X syndrome (FXS)-associated ASD. We additionally compared baseline APP derivative levels between youth with FXS-associated or idiopathic ASD. RESULTS Acamprosate use was associated with a significant reduction in plasma sAPP(total) and sAPPα levels but no change occurred in Aβ40 or Aβ42 levels in 15 youth with ASD (mean age: 11.1 years). Youth with FXS-associated ASD (n = 12) showed increased sAPPα processing compared to age-, gender- and IQ-match youth with idiopathic ASD (n = 11). CONCLUSIONS Plasma APP derivative analysis holds promise as a potential biomarker for use in ASD targeted treatment. Reduction in sAPP (total) and sAPPα may be a novel pharmacodynamic property of acamprosate. Future study is required to address limitations of the current study to determine if baseline APP derivative analysis may predict subgroups of persons with idiopathic or FXS-associated ASD who may respond best to acamprosate or to potentially other modulators of glutamate and/or GABA neurotransmission.
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Affiliation(s)
| | - Balmiki Ray
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Bryan Maloney
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Logan K. Wink
- Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Katherine Bowers
- Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Tori L. Schaefer
- Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Christopher J. McDougle
- Lurie Center for Autism, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Deborah K. Sokol
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Debomoy K. Lahiri
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, USA,Corresponding Author: Debomoy K. Lahiri, Ph.D., Professor, Departments of Psychiatry and of Medical & Molecular Genetics, Indiana University School of Medicine, Institute of Psychiatric Research, Neuroscience Research Building, 320 West 15th Street, NB 200C, Indianapolis, IN 46202-2266, USA, Tel: (317) 274-2706; Fax: (317) 231-0200
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209
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Gough M, Blanthorn-Hazell S, Delury C, Parkin E. The E1 copper binding domain of full-length amyloid precursor protein mitigates copper-induced growth inhibition in brain metastatic prostate cancer DU145 cells. Biochem Biophys Res Commun 2014; 453:741-7. [PMID: 25305487 PMCID: PMC4256156 DOI: 10.1016/j.bbrc.2014.10.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 10/02/2014] [Indexed: 02/04/2023]
Abstract
Copper plays an important role in the aetiology and growth of tumours and levels of the metal are increased in the serum and tumour tissue of patients affected by a range of cancers including prostate cancer (PCa). The molecular mechanisms that enable cancer cells to proliferate in the presence of elevated copper levels are, therefore, of key importance in our understanding of tumour growth progression. In the current study, we have examined the role played by the amyloid precursor protein (APP) in mitigating copper-induced growth inhibition of the PCa cell line, DU145. A range of APP molecular constructs were stably over-expressed in DU145 cells and their effects on cell proliferation in the presence of copper were monitored. Our results show that endogenous APP expression was induced by sub-toxic copper concentrations in DU145 cells and over-expression of the wild-type protein was able to mitigate copper-induced growth inhibition via a mechanism involving the cytosolic and E1 copper binding domains of the full-length protein. APP likely represents one of a range of copper binding proteins that PCa cells employ in order to ensure efficient proliferation despite elevated concentrations of the metal within the tumour microenvironment. Targeting the expression of such proteins may contribute to therapeutic strategies for the treatment of cancers.
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Affiliation(s)
- Mallory Gough
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK.
| | - Sophee Blanthorn-Hazell
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK.
| | - Craig Delury
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK.
| | - Edward Parkin
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK.
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210
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Guo LY, Alekseev O, Li Y, Song Y, Dunaief JL. Iron increases APP translation and amyloid-beta production in the retina. Exp Eye Res 2014; 129:31-7. [PMID: 25456519 DOI: 10.1016/j.exer.2014.10.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/10/2014] [Accepted: 10/14/2014] [Indexed: 01/16/2023]
Abstract
Age-related macular degeneration (AMD) is the most common cause of blindness among older adults in developed countries, and retinal iron accumulation may exacerbate the disease. Iron can upregulate the production of amyloid precursor protein (APP). Since amyloid-β (Aβ), a byproduct of APP proteolysis, is found in drusen, the histopathological hallmark of AMD, we tested the role of iron in regulating APP and Aβ levels in the retinal pigment epithelial cell line ARPE-19. We found that treatment with ferric ammonium citrate (FAC) increases APP at the translational level. FAC treatment also results in increased generation of APP C-terminal fragments C83 and C99, the products of APP proteolysis by α- and β-secretase, respectively, as well as levels of Aβ42, a highly aggregative amyloid species. Additionally, retinal tissue sections from a patient with aceruloplasminemia, a disease causing iron overload in the retinal pigment epithelium (RPE), showed increased Aβ deposition in the RPE and drusen. Overall, our results suggest that RPE iron overload could contribute to Aβ accumulation in the retina.
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Affiliation(s)
- Lucie Y Guo
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA 19104, USA.
| | - Oleg Alekseev
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA 19104, USA; Drexel University College of Medicine, 2900 W Queen Ln, Philadelphia, PA 19129, USA.
| | - Yafeng Li
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA 19104, USA.
| | - Ying Song
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA 19104, USA.
| | - Joshua L Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, 305 Stellar-Chance Laboratory, 422 Curie Blvd, Philadelphia, PA 19104, USA.
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211
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Cho WH, Park JC, Kim DH, Kim MS, Lee SY, Park H, Kang JH, Yeon SW, Han JS. ID1201, the ethanolic extract of the fruit of Melia toosendan ameliorates impairments in spatial learning and reduces levels of amyloid beta in 5XFAD mice. Neurosci Lett 2014; 583:170-5. [PMID: 25281546 DOI: 10.1016/j.neulet.2014.09.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/08/2014] [Accepted: 09/18/2014] [Indexed: 12/20/2022]
Abstract
A previous study has demonstrated the anti-amyloidogenic effects of the ethanolic extract of Meliae Fructus (ID1201) using cell lines with stably expressed human Swedish mutant APP695 and β-secretase 1, and 5Xfamilial AD (FAD) mice carrying five mutations. Here, we investigated the effects of ID1201 on cognitive impairment in 5XFAD mice. Daily administration of ID1201 was commenced at 3 months of age and continued for 3 months. Mice were serially trained in cued/response and place/spatial training tasks in the Morris water maze. After this training, testing for strategy preference was conducted. Non-transgenic control mice with vehicle treatment, vehicle-treated 5XFAD, and ID1201-treated 5XFAD mice showed equivalent performance in cued/response training. However, as training progressed to the subsequent place/spatial learning, vehicle-treated control and ID1201-treated 5XFAD mice differed significantly from vehicle-treated 5XFAD mice in measures of spatial learning (search error and adaptive spatial learning strategy). In the strategy preference test that followed, control mice preferred a place/spatial strategy relative to vehicle-treated 5XFAD mice, but differences between ID1201-treated 5XFAD mice and vehicle-treated 5XFAD mice were not significant. Additionally, ID1201 treatment reduced hippocampal levels of insoluble Aβ42 and increased cortical levels of soluble amyloid precursor protein α. These results indicate that ID1201 may possess potential as a therapeutic agent for Alzheimer's disease by decreasing Aβ deposits.
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212
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Dionísio PA, Amaral JD, Ribeiro MF, Lo AC, D'Hooge R, Rodrigues CM. Amyloid-β pathology is attenuated by tauroursodeoxycholic acid treatment in APP/PS1 mice after disease onset. Neurobiol Aging 2015; 36:228-40. [PMID: 25443293 DOI: 10.1016/j.neurobiolaging.2014.08.034] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 07/31/2014] [Accepted: 08/12/2014] [Indexed: 01/06/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder hallmarked by the accumulation of extracellular amyloid-β (Aβ) peptide and intraneuronal hyperphosphorylated tau, as well as chronic neuroinflammation. Tauroursodeoxycholic acid (TUDCA) is an endogenous anti-apoptotic bile acid with potent neuroprotective properties in several experimental models of AD. We have previously reported the therapeutic efficacy of TUDCA treatment before amyloid plaque deposition in APP/PS1 double-transgenic mice. In the present study, we evaluated the protective effects of TUDCA when administrated after the onset of amyloid pathology. APP/PS1 transgenic mice with 7 months of age were injected intraperitoneally with TUDCA (500 mg/kg) every 3 days for 3 months. TUDCA treatment significantly attenuated Aβ deposition in the brain, with a concomitant decrease in Aβ₁₋₄₀ and Aβ₁₋₄₂ levels. The amyloidogenic processing of amyloid precursor protein was also reduced, indicating that TUDCA interferes with Aβ production. In addition, TUDCA abrogated GSK3β hyperactivity, which is highly implicated in tau hyperphosphorylation and glial activation. This effect was likely dependent on the specific activation of the upstream kinase, Akt. Finally, TUDCA treatment decreased glial activation and reduced proinflammatory cytokine messenger RNA expression, while partially rescuing synaptic loss. Overall, our results suggest that TUDCA is a promising therapeutic strategy not only for prevention but also for treatment of AD after disease onset.
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214
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Miyazaki T, Ikeda K, Horie-Inoue K, Inoue S. Amyloid precursor protein regulates migration and metalloproteinase gene expression in prostate cancer cells. Biochem Biophys Res Commun 2014; 452:828-33. [PMID: 25218471 DOI: 10.1016/j.bbrc.2014.09.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 09/02/2014] [Indexed: 01/21/2023]
Abstract
Amyloid precursor protein (APP) is a type I transmembrane protein, and one of its processed forms, β-amyloid, is considered to play a central role in the development of Alzheimer's disease. We previously showed that APP is a primary androgen-responsive gene in prostate cancer and that its increased expression is correlated with poor prognosis for patients with prostate cancer. APP has also been implicated in several human malignancies. Nevertheless, the mechanism underlying the pro-proliferative effects of APP on cancers is still not well-understood. In the present study, we explored a pathophysiological role for APP in prostate cancer cells using siRNA targeting APP (siAPP). The proliferation and migration of LNCaP and DU145 prostate cancer cells were significantly suppressed by siAPP. Differentially expressed genes in siAPP-treated cells compared to control siRNA-treated cells were identified by microarray analysis. Notably, several metalloproteinase genes, such as ADAM10 and ADAM17, and epithelial-mesenchymal transition (EMT)-related genes, such as VIM, and SNAI2, were downregulated in siAPP-treated cells as compared to control cells. The expression of these genes was upregulated in LNCaP cells stably expressing APP when compared with control cells. APP-overexpressing LNCaP cells exhibited enhanced migration in comparison to control cells. These results suggest that APP may contribute to the proliferation and migration of prostate cancer cells by modulating the expression of metalloproteinase and EMT-related genes.
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215
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Liu CG, Wang JL, Li L, Xue LX, Zhang YQ, Wang PC. MicroRNA-135a and -200b, potential Biomarkers for Alzheimer׳s disease, regulate β secretase and amyloid precursor protein. Brain Res 2014; 1583:55-64. [PMID: 25152461 DOI: 10.1016/j.brainres.2014.04.026] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Revised: 03/17/2014] [Accepted: 04/15/2014] [Indexed: 12/31/2022]
Abstract
Amyloid precursor protein (APP) and β-site amyloid precursor protein cleaving enzyme (BACE-1) play important roles in the generation of Alzheimer׳s disease (AD), a progressive neurodegenerative disorder. In the present study, microRNA (miR) microarray was used to analyze the miR expression profiles in the hippocampi from APP/PS1 transgenic and wild type mice. The miRs with significant alteration and putative targets on APP or BACE-1 were retrieved (miR-135a, -200b and -429). The deregulations of these miRs were confirmed in mice and further verified in AD patient samples by qPCR. Primary mouse hippocampal neurons, SH-SY5Y and HEK293 cells were used to study the function of miRs on APP and BACE-1. We found that miR-135a, which was downregulated significantly in hippocampi from APP/PS1 transgenic mice compared with the wild type control, directly interacted with the 3'-UTR of BACE-1 and repressed its expression and activity. On the other hand, miR-200b and -429, which were downregulated significantly in hippocampi from APP/PS1 transgenic mice compared with the wild type control, targeted the 3'-UTR of APP and repressed its expression. Furthermore, Aβ42 could downregulate miR-200b expression which may generate a vicious cycle resulted in accumulating Aβ42. The levels of miR-135a and -200b in the serum of DAT group were significantly lower than that of control groups (P<0.05). The serum miR-200b level of MCI group was higher than that of DAT group (P<0.05) and lower than that of control group (P<0.05). We also found decreased miR-135a and -200b levels in the cerebrospinal fluid of DAT group compared with the control group (P<0.05). In conclusion, these findings showed that miR-135a, -200b and -429 may take part in the progress of AD; miR-200b was of great potential as noninvasive and easily detected blood-based biomarkers of MCI and DAT patients.
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Abstract
Interest in the amyloid precursor protein (APP) has increased in recent years due to its involvement in Alzheimer's disease. Since its molecular cloning, significant genetic and biochemical work has focused on the role of APP in the pathogenesis of this disease. Thus far, however, these studies have failed to deliver successful therapies. This suggests that understanding the basic biology of APP and its physiological role during development might be a crucial missing link for a better comprehension of Alzheimer's disease. Here, we present an overview of some of the key studies performed in various model organisms that have revealed roles for APP at different stages of neuronal development.
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Affiliation(s)
- Maya Nicolas
- VIB Center for the Biology of Disease, VIB, 3000 Leuven, Belgium Center for Human Genetics, University of Leuven School of Medicine, 3000 Leuven, Belgium Doctoral Program in Molecular and Developmental Genetics, University of Leuven Group Biomedicine, 3000 Leuven, Belgium
| | - Bassem A Hassan
- VIB Center for the Biology of Disease, VIB, 3000 Leuven, Belgium Center for Human Genetics, University of Leuven School of Medicine, 3000 Leuven, Belgium Doctoral Program in Molecular and Developmental Genetics, University of Leuven Group Biomedicine, 3000 Leuven, Belgium
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217
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Alam S, Suzuki H, Tsukahara T. Alternative splicing regulation of APP exon 7 by RBFox proteins. Neurochem Int 2014; 78:7-17. [PMID: 25125370 DOI: 10.1016/j.neuint.2014.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Revised: 07/18/2014] [Accepted: 08/01/2014] [Indexed: 02/03/2023]
Abstract
RBFox proteins are well-known alternative splicing regulators. We have shown previously that during neuronal differentiation of P19 cells induced by all-trans retinoic acid and cell aggregation, RBFox1 shows markedly increased temporal expression. To find its key splicing regulation, we examined the effect of RBFox1 on 33 previously reported and validated neuronal splicing events of P19 cells. We observed that alternative splicing of three genes, specifically, amyloid precursor protein (APP), disks large homolog 3 (DLG3), and G protein, alpha activating activity polypeptide O (GNAO1), was altered by transient RBFox1 expression in HEK293 and HeLa cells. Moreover, an RBFox1 mutant (RBFox1FA) that was unable to bind the target RNA sequence ((U)GCAUG) did not induce these splicing events. APP generates amyloid beta peptides that are involved in the pathology of Alzheimer's disease, and therefore we examined APP alternative splicing regulation by RBFox1 and other splicing regulators. Our results indicated that RBFox proteins promote the skipping of APP exon 7, but not the inclusion of exon 8. We made APP6789 minigenes and observed that two (U)GCAUG sequences, located upstream of exon 7 and in exon 7, functioned to induce skipping of exon 7 by RBFox proteins. Overall, RBFox proteins may shift APP from exon 7 containing isoforms, APP770 and APP751, toward the exon 7 lacking isoform, APP695, which is predominant in neural tissues.
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Affiliation(s)
- Shafiul Alam
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
| | - Hitoshi Suzuki
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan; Centre for Nano Materials and Technology, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
| | - Toshifumi Tsukahara
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
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218
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Lee M, McGeer E, McGeer PL. Activated human microglia stimulate neuroblastoma cells to upregulate production of beta amyloid protein and tau: implications for Alzheimer's disease pathogenesis. Neurobiol Aging 2014; 36:42-52. [PMID: 25169677 DOI: 10.1016/j.neurobiolaging.2014.07.024] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 07/19/2014] [Accepted: 07/21/2014] [Indexed: 12/14/2022]
Abstract
Neuroinflammation is hypothesized to be a major driving force behind Alzheimer's disease (AD) pathogenesis. This hypothesis predicts that activated microglial cells can stimulate neurons to produce excessive amounts of β-amyloid protein (Aβ₁₋₄₂) and tau. The excess Aβ₁₋₄₂ forms extracellular deposits which stimulate further microglial activation. The excess tau is partially released but also becomes phosphorylated forming intracellular neurofibrillary deposits. The end result is a positive feedback mechanism which drives the disease development. To test the viability of this hypothesis, we exposed differentiated SH-SY5Y and N-tera2/D1 (N-tera2) cells to conditioned medium (CM) from LPS/IFNγ-stimulated human microglia. We found that the CM caused a large increase in the production and release of Aβ and tau. The CM also caused SH-SY5Y cells to increase their expression of amyloid precursor protein and release of its β-secretase cleaved products (sAPPβs) as well as Aβ oligomers, but the CM reduced release of its α-secretase cleaved products (sAPPαs). Direct treatment of SH-SY5Y and N-tera2 cells with the inflammatory cytokines IL-6 and IL-1β as well as with Aβ₁₋₄₂, resulted in an increase in tau messenger RNA and protein expression. Pretreatment of LPS/IFNγ-stimulated human microglia cells with the nonsteroidal anti-inflammatory drugs ibuprofen and aspirin, the antioxidant GSH, the H₂S donor NaSH, and the anti-inflammatory cytokine IL-10, resulted in a CM with diminished ability to stimulate tau expression. There was no effect on the morphology of SH-SY5Y cells, or on their viability, following exposure to micromolar levels of Aβ₁₋₄₂. Our data indicate that reactive microglia play an important role in governing the expression of Aβ and tau, and therefore the progression of AD. They provide further evidence that appropriate anti-inflammatory treatment should be beneficial in AD.
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Affiliation(s)
- Moonhee Lee
- Kinsmen Laboratory of Neurological Research, Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Edith McGeer
- Kinsmen Laboratory of Neurological Research, Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Patrick L McGeer
- Kinsmen Laboratory of Neurological Research, Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, Canada.
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219
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Klevanski M, Saar M, Baumkötter F, Weyer SW, Kins S, Müller UC. Differential role of APP and APLPs for neuromuscular synaptic morphology and function. Mol Cell Neurosci 2014; 61:201-10. [PMID: 24998676 DOI: 10.1016/j.mcn.2014.06.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 06/02/2014] [Accepted: 06/05/2014] [Indexed: 11/26/2022] Open
Abstract
The analysis of mouse models indicated that APP and the related APLPs are important for synapse formation and function. The synaptic role of APP is, however, complex due to partially overlapping functions within the gene family. APP/APLPs are proteolytically cleaved and have both adhesive and signaling properties. Mice lacking individual APP family members are viable, whereas APP/APLP2 and APLP1/APLP2 double knockout (DKO) mice die shortly after birth. Here, we analyzed the morphology of the neuromuscular junction (NMJ) of lethal APLP1/APLP2-DKO mice in comparison to lethal APP/APLP2-DKO mutants and viable single KO mice. We report that, surprisingly, the NMJ phenotype of APLP1/APLP2-DKO mice shows striking differences as compared to APP/APLP2-DKO mice. Unexpectedly, APLP1/APLP2-DKO mice exhibit normal endplate patterning and lack presynaptic nerve terminal sprouting. However, at the level of individual synapses we show that APLP1/APLP2-DKO mice exhibit reduced size of pre- and postsynaptic compartments and reduced colocalization. As APP/APLP2-DKO and APLP1/APLP2-DKO mice show similar penetrance of early postnatal lethality, this suggests that deficits at the level of individual synapses due to impaired synaptic apposition and/or deficits in transmitter release may cause lethality. Using an in vitro cell-adhesion assay, we observed that APP trans-dimerization is considerably less efficient than APLP2 trans-interaction. Thus, differences between APP/APLP2 and APP/APLP1 NMJ formation may be in part explained by differences in APP/APLP2 trans-dimerization properties. Collectively, our study further highlights the distinct and essential role of APLP2 at NMJ synapses that cannot be compensated by APP.
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Affiliation(s)
- Maja Klevanski
- Department of Bioinformatics and Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
| | - Martina Saar
- Department of Bioinformatics and Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
| | - Frederik Baumkötter
- Department of Human Biology and Human Genetics, Technical University of Kaiserslautern, Erwin-Schrödinger-Strasse 13, 67663 Kaiserslautern, Germany
| | - Sascha W Weyer
- Department of Bioinformatics and Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
| | - Stefan Kins
- Department of Human Biology and Human Genetics, Technical University of Kaiserslautern, Erwin-Schrödinger-Strasse 13, 67663 Kaiserslautern, Germany
| | - Ulrike C Müller
- Department of Bioinformatics and Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany.
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220
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Zawilla NH, Taha FM, Kishk NA, Farahat SA, Farghaly M, Hussein M. Occupational exposure to aluminum and its amyloidogenic link with cognitive functions. J Inorg Biochem 2014; 139:57-64. [PMID: 24973993 DOI: 10.1016/j.jinorgbio.2014.06.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 05/29/2014] [Accepted: 06/02/2014] [Indexed: 11/26/2022]
Abstract
As many other metals, aluminum is a widely recognized neurotoxicant and its link with neurodegenerative disorders has been the subject of scientific debate. One proposal focuses on amyloid β deposition (amyloidogenesis) as the key player in triggering neuronal dysfunction the so-called amyloid cascade hypothesis. We undertook this study first to investigate the cognition status of workers exposed to Al dust in an Al factory in Southern Cairo, second, to evaluate serum amyloid precursor protein (APP) and cathepsin D (CD) enzyme activity to study the possible role of Al in amyloidogenesis, and finally to explore the relation between these potential biomarkers and cognitive functions. The study was conducted on 54 exposed workers and 51 matched controls. They were subjected to questionnaire, neurological examination and a cognitive test battery, Addenbrooke's Cognitive Examination - Revised (ACE-R). Serum Al, APP and CD enzyme activity were measured. A significant increase of serum Al was found in the exposed workers with an associated increase in serum APP and decrement in CD activity. The exposed workers displayed poor performance on the ACE-R test. No significant correlation was detected between ACE-R test total score and either APP or CD activity. We concluded that occupational exposure to Al is associated with cognitive impairment. The effect of occupational Al exposure on the serum levels of APP and CD activity may be regarded as a possible mechanism of Al in amyloidogenesis. However, our findings do not support the utility of serum APP and CD activity as screening markers for early or preclinical cognitive impairment.
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Affiliation(s)
- N H Zawilla
- Department of Occupational & Environmental Medicine, Faculty of Medicine, Cairo University, Egypt
| | - F M Taha
- Department of Medical Biochemistry, Faculty of Medicine, Cairo University, Egypt.
| | - N A Kishk
- Department of Neurology, Faculty of Medicine, Cairo University, Egypt
| | - S A Farahat
- Department of Occupational & Environmental Medicine, Faculty of Medicine, Cairo University, Egypt
| | - M Farghaly
- Department of Neurology, Faculty of Medicine, Cairo University, Egypt
| | - M Hussein
- Department of Neurology, Faculty of Medicine, Bani-suef University, Egypt
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221
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Hoefgen S, Coburger I, Roeser D, Schaub Y, Dahms SO, Than ME. Heparin induced dimerization of APP is primarily mediated by E1 and regulated by its acidic domain. J Struct Biol 2014; 187:30-37. [PMID: 24859793 DOI: 10.1016/j.jsb.2014.05.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 05/08/2014] [Accepted: 05/14/2014] [Indexed: 11/24/2022]
Abstract
The amyloid precursor protein (APP) and its cellular processing are believed to be centrally involved in the etiology of Alzheimer's disease (AD). In addition, many physiological functions have been described for APP, including a role in cell-cell- and cell-ECM-adhesion as well as in axonal outgrowth. We show here the molecular determinants of the oligomerization/dimerization of APP, which is central for its cellular (mis)function. Using size exclusion chromatography (SEC), dynamic light scattering and SEC-coupled static light scattering we demonstrate that the dimerization of APP is energetically induced by a heparin mediated dimerization of the E1 domain, which results in a dimeric interaction of E2. We also show that the acidic domain (AcD) interferes with the dimerization of E1 and propose a model where both, cis- and trans-dimerization occur dependent on cellular localization and function.
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Affiliation(s)
- Sandra Hoefgen
- Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), Protein Crystallography Group, Beutenbergstr. 11, 07745 Jena, Germany
| | - Ina Coburger
- Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), Protein Crystallography Group, Beutenbergstr. 11, 07745 Jena, Germany
| | - Dirk Roeser
- Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), Protein Crystallography Group, Beutenbergstr. 11, 07745 Jena, Germany
| | - Yvonne Schaub
- Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), Protein Crystallography Group, Beutenbergstr. 11, 07745 Jena, Germany
| | - Sven O Dahms
- Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), Protein Crystallography Group, Beutenbergstr. 11, 07745 Jena, Germany
| | - Manuel E Than
- Leibniz Institute for Age Research - Fritz Lipmann Institute (FLI), Protein Crystallography Group, Beutenbergstr. 11, 07745 Jena, Germany.
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222
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Li S, Liu B, Zhang L, Rong L. Amyloid beta peptide is elevated in osteoporotic bone tissues and enhances osteoclast function. Bone 2014; 61:164-75. [PMID: 24473375 DOI: 10.1016/j.bone.2014.01.010] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 12/23/2013] [Accepted: 01/17/2014] [Indexed: 12/13/2022]
Abstract
PURPOSE Epidemiological studies show that patients with Alzheimer's disease (AD) have an increased risk of developing osteoporotic hip fracture. However, whether abnormal amyloid beta peptide (Aβ) deposition, one of the pathological hallmarks of AD, also occurs in osteoporosis and the relationship between Aβ and human osteoporosis remain unknown. This study addressed these issues. METHODS Forty-five female patients (osteoporosis 21, osteopenia 16 and normal 8) with osteoporotic/traumatic vertebral compression fractures were enrolled and Aβ42 and amyloid precursor protein (APP) levels assessed in the biopsy specimens of vertebral trabecular bone using immunohistochemistry (IHC) staining and semi-quantitative evaluation assays. Spearman rank correlation analysis was applied to explore the association between Aβ42/APP levels and the corresponding bone mineral density (BMD). Moreover, immunofluorescent assays and laser scanning confocal microscopy assays were used to examine the expression patterns of Aβ42/APP in patient bone tissues and osteocytes. Additionally, eight female patients with osteoporotic/traumatic femoral neck fractures, including two control patients were selected and Aβ42 and APP were identified in the femoral necks by RT-PCR and Western blotting (WB) assays. Next, a rat model of ovariectomy-induced osteoporosis was created and we evaluated Aβ42 and APP expression differences in the proximal tibia by IHC and RT-PCR and WB assays in comparison with a sham-operation group. Finally, the RAW264.7 cell line and human bone marrow monocyte (hBMMC) derived osteoclasts and human Aβ42 co-culture assays were performed to investigate the effect of Aβ42 on osteoclasts cell viability, number, differentiation and activation by the Cell Counting Kit-8 assay, tartrate resistant acid phosphatase staining assay, RT-PCR assay measuring the lytic gene expression and hydroxyapatite resorption assay respectively. RESULTS The mRNA and protein expression levels of Aβ42 and APP were elevated remarkably in the osteoporotic bone tissues both from human and ovariectomized rats when compared with the age-/sex-matched controls. Moreover, the expression levels had a negative correlation with corresponding BMD in patients (RAβ42=-0.617, p<0.0001; RAPP=-0.531, p=0.0002). In addition, Aβ42 was located mainly in the membrane and cytoplasm of osteocytes and in the extracellular matrix, while APP was largely located in the membrane of the osteocytes. Finally, Aβ42 can potently enhance osteoclasts differentiation and activation but had no effect on osteoclasts cell viability or number (dose- and time-dependency did not exist and oligomerization of Aβ42 was not a prerequisite in the osteoclastogenesis assay). CONCLUSIONS Aβ is relevant to human osteoporosis and may have an important role in the pathogenesis of osteoporosis.
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Affiliation(s)
- Shangfu Li
- Department of Spine Surgery, the Third Affiliated Hospital of Sun Yat-sen University, TianHe Road 600, TianHe District, Guangzhou Guangdong, 510630, PR China.
| | - Bin Liu
- Department of Spine Surgery, the Third Affiliated Hospital of Sun Yat-sen University, TianHe Road 600, TianHe District, Guangzhou Guangdong, 510630, PR China.
| | - Liangming Zhang
- Department of Spine Surgery, the Third Affiliated Hospital of Sun Yat-sen University, TianHe Road 600, TianHe District, Guangzhou Guangdong, 510630, PR China.
| | - Limin Rong
- Department of Spine Surgery, the Third Affiliated Hospital of Sun Yat-sen University, TianHe Road 600, TianHe District, Guangzhou Guangdong, 510630, PR China.
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223
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Ayton S, Zhang M, Roberts BR, Lam LQ, Lind M, McLean C, Bush AI, Frugier T, Crack PJ, Duce JA. Ceruloplasmin and β- amyloid precursor protein confer neuroprotection in traumatic brain injury and lower neuronal iron. Free Radic Biol Med 2014; 69:331-7. [PMID: 24509156 DOI: 10.1016/j.freeradbiomed.2014.01.041] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 01/10/2014] [Accepted: 01/31/2014] [Indexed: 10/25/2022]
Abstract
Traumatic brain injury (TBI) is in part complicated by pro-oxidant iron elevation independent of brain hemorrhage. Ceruloplasmin (CP) and β-amyloid protein precursor (APP) are known neuroprotective proteins that reduce oxidative damage through iron regulation. We surveyed iron, CP, and APP in brain tissue from control and TBI-affected patients who were stratified according to time of death following injury. We observed CP and APP induction after TBI accompanying iron accumulation. Elevated APP and CP expression was also observed in a mouse model of focal cortical contusion injury concomitant with iron elevation. To determine if changes in APP or CP were neuroprotective we employed the same TBI model on APP(-/-) and CP(-/-) mice and found that both exhibited exaggerated infarct volume and iron accumulation postinjury. Evidence supports a regulatory role of both proteins in defence against iron-induced oxidative damage after TBI, which presents as a tractable therapeutic target.
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Affiliation(s)
- Scott Ayton
- Oxidation Biology Unit, The Florey Institute of Neuroscience and Mental Health
| | - Moses Zhang
- Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Blaine R Roberts
- Oxidation Biology Unit, The Florey Institute of Neuroscience and Mental Health
| | - Linh Q Lam
- Oxidation Biology Unit, The Florey Institute of Neuroscience and Mental Health
| | - Monica Lind
- Oxidation Biology Unit, The Florey Institute of Neuroscience and Mental Health
| | - Catriona McLean
- Department of Pathology, and The University of Melbourne, Parkville, VIC 3010, Australia
| | - Ashley I Bush
- Oxidation Biology Unit, The Florey Institute of Neuroscience and Mental Health; Department of Pathology, and The University of Melbourne, Parkville, VIC 3010, Australia
| | - Tony Frugier
- Department of Anatomy and Cell Biology, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Peter J Crack
- Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, VIC 3010, Australia
| | - James A Duce
- Oxidation Biology Unit, The Florey Institute of Neuroscience and Mental Health; School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, North Yorkshire, UK.
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224
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Nguyen KV. Epigenetic regulation in amyloid precursor protein and the Lesch-Nyhan syndrome. Biochem Biophys Res Commun 2014; 446:1091-5. [PMID: 24680827 DOI: 10.1016/j.bbrc.2014.03.062] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 03/16/2014] [Indexed: 12/26/2022]
Abstract
Lesch-Nyhan syndrome (LNS) is a neurogenetic disorder of purine metabolism in which the enzyme, hypoxanthine-guanine phosphoribosyltransferase (HPRT) is defective. A major unsolved question is how the loss of HPRT enzyme function affects the brain to cause the neurobehavioural syndrome in LNS and its attenuated variants (LNVs). To address this issue, a search for a link between LNS and the amyloid precursor protein (APP) is developed. Here, I identified, for the first time in fibroblasts from normal subjects as well as from LNS and LNV patients: (a) several APP-mRNA isoforms encoding divers APP protein isoforms ranging from 120 to 770 amino acids (with or without mutations and/or deletions) accounted for epigenetic mechanisms in the regulation of alternative APP pre-mRNA splicing and (b) five novel independent polymorphisms in the APP promoter: -956A>G, -1023T>C, -1161A>G, -2224G>A, -2335C>T relative to the transcription start site. A role for epistasis between mutated HPRT and APP genes affecting the regulation of alternative APP pre-mRNA splicing in LNS is suggested. An accurate quantification of various APP isoforms in brain tissues for detection of initial pathological changes or pathology development is needed. My findings may provide new directions not only for investigating the role of APP in neuropathology associated with HPRT-deficiency in LNS but also for the research in neurodevelopmental and neurodegenerative disorders by which various APP isoforms involved in the pathogenesis of the diseases such as Alzheimer's disease.
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Affiliation(s)
- Khue Vu Nguyen
- Department of Medicine, Biochemical Genetics and Metabolism, The Mitochondrial and Metabolic Disease Center, School of Medicine, University of California, San Diego, Building CTF, Room C-103, 214 Dickinson Street, San Diego, CA 92103-8467, USA; Department of Pediatrics, University of California, San Diego, School of Medicine, San Diego, La Jolla, CA 92093, USA.
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225
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Pajoohesh-Ganji A, Burns MP, Pal-Ghosh S, Tadvalkar G, Hokenbury NG, Stepp MA, Faden AI. Inhibition of amyloid precursor protein secretases reduces recovery after spinal cord injury. Brain Res 2014; 1560:73-82. [PMID: 24630972 DOI: 10.1016/j.brainres.2014.02.049] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 02/24/2014] [Accepted: 02/25/2014] [Indexed: 12/18/2022]
Abstract
Amyloid-β (Aβ) is produced through the enzymatic cleavage of amyloid precursor protein (APP) by β (Bace1) and γ-secretases. The accumulation and aggregation of Aβ as amyloid plaques is the hallmark pathology of Alzheimer׳s disease and has been found in other neurological disorders, such as traumatic brain injury and multiple sclerosis. Although the role of Aβ after injury is not well understood, several studies have reported a negative correlation between Aβ formation and functional outcome. In this study we show that levels of APP, the enzymes cleaving APP (Bace1 and γ-secretase), and Aβ are significantly increased from 1 to 3 days after impact spinal cord injury (SCI) in mice. To determine the role of Aβ after SCI, we reduced or inhibited Aβ in vivo through pharmacological (using DAPT) or genetic (Bace1 knockout mice) approaches. We found that these interventions significantly impaired functional recovery as evaluated by white matter sparing and behavioral testing. These data are consistent with a beneficial role for Aβ after SCI.
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Affiliation(s)
| | - Mark P Burns
- Georgetown University, Washington, DC, United States
| | | | - Gauri Tadvalkar
- The George Washington University, Washington, DC, United States
| | - Nicole G Hokenbury
- The George Washington University, Washington, DC, United States; Georgetown University, Washington, DC, United States; University of Maryland, Baltimore, United States
| | - Mary Ann Stepp
- The George Washington University, Washington, DC, United States
| | - Alan I Faden
- University of Maryland, Baltimore, United States
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226
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Song JW, Choi BS. Mercury induced the Accumulation of Amyloid Beta (Aβ) in PC12 Cells: The Role of Production and Degradation of Aβ. Toxicol Res 2014; 29:235-40. [PMID: 24578793 PMCID: PMC3936175 DOI: 10.5487/tr.2013.29.4.235] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 12/16/2013] [Accepted: 12/17/2013] [Indexed: 01/15/2023] Open
Abstract
Extracellular accumulation of amyloid beta protein (Aβ) plays a central role in Alzheimer’s disease (AD). Some metals, such as copper, lead, and aluminum can affect the Aβ accumulation in the brain. However, the effect of mercury on Aβ accumulation in the brain is not clear. Thus, this study was proposed to estimate whether mercury concentration affects Aβ accumulation in PC12 cells. We treated 10, 100, and 1000 nM HgCl2 (Hg) or CH3HgCl2 (MeHg) for 48 hr in PC12 cells. After treatment, Aβ40 in culture medium increased in a dose- and time-dependent manner. Hg and MeHg increased amyloid precursor protein (APP), which is related to Aβ production. Neprilysin (NEP) levels in PC12 cells were decreased by Hg and MeHg treatment. These results suggested that Hg induced Aβ accumulation through APP overproduction and reduction of NEP.
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Affiliation(s)
- Ji-Won Song
- Department of Preventive Medicine, College of Medicine, Chung-Ang University, Seoul, Korea
| | - Byung-Sun Choi
- Department of Preventive Medicine, College of Medicine, Chung-Ang University, Seoul, Korea
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227
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Hata Y, Yoshida K, Kinoshita K, Nishida N. Sudden unexpected death owing to unilateral medial medullary infarction with early involvement of the respiratory center. Leg Med (Tokyo) 2014; 16:146-9. [PMID: 24508471 DOI: 10.1016/j.legalmed.2014.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 01/14/2014] [Accepted: 01/14/2014] [Indexed: 11/26/2022]
Abstract
A 64-year-old woman was found dead in her home. At autopsy, although relatively fresh bruises were found on her body, no lethal injury was observed in an internal observation. Mild edematous swelling of the right half of the medulla oblongata was observed. There was acute medial medullary infarction (MMI), which mainly involved the nucleus hypoglossi, medial lemniscus, hypoglossal root, inferior olivary nucleus, and pyramidal tract. Subacute infarction of the lower part of the cerebellum was also found, and severe atherosclerosis of the right vertebral artery containing thrombi was found as the culprit lesion. Immunohistochemistry using amyloid precursor protein (APP) was positive in neuronal tissue in the nucleus ambiguus, despite not showing coagulative necrosis in the nucleus. Therefore, acute ischemic necrosis of the nucleus ambiguus, which is considered to be a component of the dorsal respiratory group, may be a significant finding for her expected death. Immunohistochemistry of APP may be useful for confirming the precise extent of acute ischemia in brain stem infarction, such as unilateral MMI.
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Affiliation(s)
- Yukiko Hata
- Department of Legal Medicine, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Koji Yoshida
- Department of Neurology, Toyama University Hospital, Toyama, Japan
| | - Koshi Kinoshita
- Department of Legal Medicine, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Naoki Nishida
- Department of Legal Medicine, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
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228
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Bandyopadhyay S, Rogers JT. Alzheimer’s disease therapeutics targeted to the control of amyloid precursor protein translation: maintenance of brain iron homeostasis. Biochem Pharmacol. 2014;88:486-494. [PMID: 24513321 DOI: 10.1016/j.bcp.2014.01.032] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 01/16/2014] [Accepted: 01/22/2014] [Indexed: 11/20/2022]
Abstract
The neurotoxicity of amyloid beta (Aβ), a major cleavage product of the amyloid precursor protein (APP), is enhanced by iron, as found in the amyloid plaques of Alzheimer's disease (AD) patients. By contrast, the long-known neuroprotective activity of APP is evident after α-secretase cleavage of the precursor to release sAPPα, and depends on the iron export actions of APP itself. The latter underlie its neurotrophic and protective effects in facilitating the homeostatic actions of ferroportin mediated-iron export. Thus APP-dependent iron export may alleviate oxidative stress by minimizing labile iron thus protecting neurons from iron overload during stroke and hemorrhage. Consistent with this, altered phosphorylation of iron-regulatory protein-1 (IRP1) and its signaling processes play a critical role in modulating APP translation via the 5' untranslated region (5'UTR) of its transcript. The APP 5'UTR region encodes a functional iron-responsive element (IRE) RNA stem loop that represents a potential target for modulating APP production. Targeted regulation of APP gene expression via the modulation of 5'UTR sequence function represents a novel approach for the potential treatment of AD since altering APP translation can be used to improve both the protective brain iron balance and provide anti-amyloid efficacy. Approved drugs including paroxetine and desferrioxamine and several novel compounds have been identified that suppress abnormal metal-promoted Aβ accumulation with a subset of these acting via APP 5'UTR-dependent mechanisms to modulate APP translation and cleavage to generate the non-toxic sAPPα.
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229
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Peviani M, Salvaneschi E, Bontempi L, Petese A, Manzo A, Rossi D, Salmona M, Collina S, Bigini P, Curti D. Neuroprotective effects of the Sigma-1 receptor (S1R) agonist PRE-084, in a mouse model of motor neuron disease not linked to SOD1 mutation. Neurobiol Dis 2014; 62:218-32. [PMID: 24141020 DOI: 10.1016/j.nbd.2013.10.010] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 09/12/2013] [Accepted: 10/07/2013] [Indexed: 12/14/2022] Open
Abstract
The identification of novel molecular targets crucially involved in motor neuron degeneration/survival is a necessary step for the development of hopefully more effective therapeutic strategies for amyotrophic lateral sclerosis (ALS) patients. In this view, S1R, an endoplasmic reticulum (ER)-resident receptor with chaperone-like activity, has recently attracted great interest. S1R is involved in several processes leading to acute and chronic neurodegeneration, including ALS pathology. Treatment with the S1R agonist PRE-084 improves locomotor function and motor neuron survival in presymptomatic and early symptomatic mutant SOD1-G93A ALS mice. Here, we tested the efficacy of PRE-084 in a model of spontaneous motor neuron degeneration, the wobbler mouse (wr) as a proof of concept that S1R may be regarded as a key therapeutic target also for ALS cases not linked to SOD1 mutation. Increased staining for S1R was detectable in morphologically spared cervical spinal cord motor neurons of wr mice both at early (6th week) and late (12th week) phases of clinical progression. S1R signal was also detectable in hypertrophic astrocytes and reactive microglia of wr mice. Chronic treatment with PRE-084 (three times a week, for 8weeks), starting at symptom onset, significantly increased the levels of BDNF in the gray matter, improved motor neuron survival and ameliorated paw abnormality and grip strength performance. In addition, the treatment significantly reduced the number of reactive astrocytes whereas, that of CD11b+ microglial cells was increased. A deeper evaluation of microglial markers revealed significant increased number of cells positive for the pan-macrophage marker CD68 and of CD206+ cells, involved in tissue restoration, in the white matter of PRE-084-treated mice. The mRNA levels of TNF-α and IL-1β were not affected by PRE-084 treatment. Thus, our results support pharmacological manipulation of S1R as a promising strategy to cure ALS and point to increased availability of growth factors and modulation of astrocytosis and of macrophage/microglia as part of the mechanisms involved in S1R-mediated neuroprotection.
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Affiliation(s)
- Marco Peviani
- Department of Biology and Biotechnology "L. Spallanzani", Laboratory of Cellular & Molecular Neuropharmacology, University of Pavia, Pavia, Italy
| | - Eleonora Salvaneschi
- Department of Biology and Biotechnology "L. Spallanzani", Laboratory of Cellular & Molecular Neuropharmacology, University of Pavia, Pavia, Italy
| | - Leonardo Bontempi
- Department of Biology and Biotechnology "L. Spallanzani", Laboratory of Cellular & Molecular Neuropharmacology, University of Pavia, Pavia, Italy
| | - Alessandro Petese
- Department of Biology and Biotechnology "L. Spallanzani", Laboratory of Cellular & Molecular Neuropharmacology, University of Pavia, Pavia, Italy
| | - Antonio Manzo
- Rheumatology and Translational Immunology Research Laboratories (LaRIT), Division of Rheumatology, IRCCS Policlinico S. Matteo Foundation/University of Pavia, Italy
| | - Daniela Rossi
- Department of Drug Science, Laboratory of Medicinal Chemistry, University of Pavia, Pavia, Italy
| | - Mario Salmona
- IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Simona Collina
- Department of Drug Science, Laboratory of Medicinal Chemistry, University of Pavia, Pavia, Italy
| | - Paolo Bigini
- IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Daniela Curti
- Department of Biology and Biotechnology "L. Spallanzani", Laboratory of Cellular & Molecular Neuropharmacology, University of Pavia, Pavia, Italy.
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230
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Bamne MN, Demirci FY, Berman S, Snitz BE, Rosenthal SL, Wang X, Lopez OL, Kamboh MI. Investigation of an amyloid precursor protein protective mutation (A673T) in a North American case-control sample of late-onset Alzheimer's disease. Neurobiol Aging 2014; 35:1779.e15-6. [PMID: 24529499 DOI: 10.1016/j.neurobiolaging.2014.01.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 01/19/2014] [Indexed: 12/15/2022]
Abstract
A rare amyloid precursor protein gene variant, A673T (rs63750847) was recently reported to protect against Alzheimer's disease and age-related cognitive decline among Icelanders and the same rare variant was observed also in Finnish, Norwegian, and Swedish populations. We investigated this variant in 1674 late-onset Alzheimer's disease cases and 2644 elderly control subjects, all North American Whites (US Whites). We did not observe any example of the A673T variant in our large sample. Our findings suggest that this rare variant could be specific to the individuals of the origin from the Nordic countries.
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Affiliation(s)
- Mikhil N Bamne
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - F Yesim Demirci
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Sarah Berman
- Department of Neurology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Beth E Snitz
- Department of Neurology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Samantha L Rosenthal
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Xingbin Wang
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Oscar L Lopez
- Department of Neurology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - M Ilyas Kamboh
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA.
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231
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Abstract
Endothelial nitric oxide (NO) is generated by constitutively active endothelial nitric oxide synthase (eNOS), an essential enzyme responsible for cardiovascular homeostasis. Historically, endothelial NO was first recognized as a major vasodilator involved in control of vasomotor function and local blood flow. In this review, our attention is focused on the emerging role of endothelial NO in linking cerebrovascular function with cognition. We will discuss the recognized ability of endothelial NO to modulate processing of amyloid precursor protein (APP), influence functional status of microglia, and affect cognitive function. Existing evidence suggests that the loss of NO in cultured human cerebrovascular endothelium causes increased expression of APP and β-site APP-cleaving enzyme 1 (BACE1) thereby resulting in increased secretion of amyloid β peptides (Aβ1-40 and Aβ1-42). Furthermore, increased expression of APP and BACE1 as well as increased production of Aβ peptides was detected in the cerebral microvasculature and brain tissue of eNOS-deficient mice. Since Aβ peptides are considered major cytotoxic molecules responsible for the pathogenesis of Alzheimer's disease, these observations support the concept that a loss of endothelial NO might significantly contribute to the initiation and progression of cognitive decline. In addition, genetic inactivation of eNOS causes activation of microglia and promotes a pro-inflammatory phenotype in the brain. Behavioural analysis revealed that eNOS-deficient mice exhibit impaired cognitive performance thereby indicating that selective loss of endothelial NO has a detrimental effect on the function of neuronal cells. Together with findings from prior studies demonstrating the ability of endothelial NO to affect synaptic plasticity, mitochondrial biogenesis, and function of neuronal progenitor cells, it is becoming apparent that the role of endothelial NO in the control of central nervous system function is very complex. We propose that endothelial NO represents the key molecule linking cerebrovascular and neuronal function.
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Affiliation(s)
- Zvonimir S Katusic
- Department of Anesthesiology, Vascular Biology Laboratory, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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232
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Fiorini A, Sultana R, Förster S, Perluigi M, Cenini G, Cini C, Cai J, Klein JB, Farr SA, Niehoff ML, Morley JE, Kumar VB, Butterfield DA. Antisense directed against PS-1 gene decreases brain oxidative markers in aged senescence accelerated mice (SAMP8) and reverses learning and memory impairment: a proteomics study. Free Radic Biol Med 2013; 65:1-14. [PMID: 23777706 PMCID: PMC3855183 DOI: 10.1016/j.freeradbiomed.2013.06.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 04/29/2013] [Accepted: 06/07/2013] [Indexed: 01/12/2023]
Abstract
Amyloid β-peptide (Aβ) plays a central role in the pathophysiology of Alzheimer's disease (AD) through the induction of oxidative stress. This peptide is produced by proteolytic cleavage of amyloid precursor protein (APP) by the action of β- and γ-secretases. Previous studies demonstrated that reduction of Aβ, using an antisense oligonucleotide (AO) directed against the Aβ region of APP, reduced oxidative stress-mediated damage and prevented or reverted cognitive deficits in senescence-accelerated prone mice (SAMP8), a useful animal model for investigating the events related to Aβ pathology and possibly to the early phase of AD. In the current study, aged SAMP8 were treated by AO directed against PS-1, a component of the γ-secretase complex, and tested for learning and memory in T-maze foot shock avoidance and novel object recognition. Brain tissue was collected to identify the decrease of oxidative stress and to evaluate the proteins that are differently expressed and oxidized after the reduction in free radical levels induced by Aβ. We used both expression proteomics and redox proteomics approaches. In brain of AO-treated mice a decrease of oxidative stress markers was found, and the proteins identified by proteomics as expressed differently or nitrated are involved in processes known to be impaired in AD. Our results suggest that the treatment with AO directed against PS-1 in old SAMP8 mice reverses learning and memory deficits and reduces Aβ-mediated oxidative stress with restoration to the normal condition and identifies possible pharmacological targets to combat this devastating dementing disease.
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Affiliation(s)
- Ada Fiorini
- Department of Biochemical Sciences, Sapienza University of Rome, 00185 Rome, Italy; Department of Chemistry, Center of Membrane Sciences, Sanders Brown Center on Aging, University of Kentucky, Lexington, KY 40506, USA
| | - Rukhsana Sultana
- Department of Chemistry, Center of Membrane Sciences, Sanders Brown Center on Aging, University of Kentucky, Lexington, KY 40506, USA
| | - Sarah Förster
- Department of Chemistry, Center of Membrane Sciences, Sanders Brown Center on Aging, University of Kentucky, Lexington, KY 40506, USA; Department of Biochemistry, Institute of Animal Sciences, University of Bonn, Bonn, Germany
| | - Marzia Perluigi
- Department of Biochemical Sciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Giovanna Cenini
- Department of Chemistry, Center of Membrane Sciences, Sanders Brown Center on Aging, University of Kentucky, Lexington, KY 40506, USA
| | - Chiara Cini
- Department of Biochemical Sciences, Sapienza University of Rome, 00185 Rome, Italy
| | - Jian Cai
- Department of Nephrology and Proteomics Center, University of Louisville, Louisville, KY 40292, USA
| | - Jon B Klein
- Department of Nephrology and Proteomics Center, University of Louisville, Louisville, KY 40292, USA
| | - Susan A Farr
- Division of Geriatric Medicine Saint Louis University School of Medicine, St. Louis, MO, USA; VA Medical Center, St. Louis, MO, USA
| | - Michael L Niehoff
- Division of Geriatric Medicine Saint Louis University School of Medicine, St. Louis, MO, USA; VA Medical Center, St. Louis, MO, USA
| | - John E Morley
- Division of Geriatric Medicine Saint Louis University School of Medicine, St. Louis, MO, USA; VA Medical Center, St. Louis, MO, USA
| | - Vijaya B Kumar
- Division of Geriatric Medicine Saint Louis University School of Medicine, St. Louis, MO, USA; VA Medical Center, St. Louis, MO, USA
| | - D Allan Butterfield
- Department of Chemistry, Center of Membrane Sciences, Sanders Brown Center on Aging, University of Kentucky, Lexington, KY 40506, USA.
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233
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Manczak M, Reddy PH. RNA silencing of genes involved in Alzheimer's disease enhances mitochondrial function and synaptic activity. Biochim Biophys Acta 2013; 1832:2368-78. [PMID: 24063855 PMCID: PMC3830527 DOI: 10.1016/j.bbadis.2013.09.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/26/2013] [Accepted: 09/16/2013] [Indexed: 01/08/2023]
Abstract
An age-dependent increase in mRNA levels of the amyloid precursor protein (APP), the microtubule-associated protein Tau, and voltage-dependent anion channel 1 (VDAC1) genes are reported to be toxic to neurons affected by Alzheimer's disease (AD). However, the underlying toxic nature of these genes is not completely understood. The purpose of our study was to determine the effects of RNA silencing of APP, Tau, and VDAC1 genes in AD pathogenesis. Using human neuroblastoma (SHSY5Y) cells, we first silenced RNA for APP, Tau, and VDAC1 genes, and then performed real-time RT-PCR analysis to measure mRNA levels of 34 genes that are involved in AD pathogenesis. Using biochemical assays, we also assessed mitochondrial function by measuring levels of H2O2 production, lipid peroxidation, cytochrome c oxidase activity, ATP production, and GTPase enzymatic activity. We found that increased mRNA expression of synaptic function and mitochondrial fission genes, and reduced levels of mitochondrial fusion genes in RNA silenced the SHSY5Y cells for APP, Tau and VDAC1 genes relative to the control SHSY5Y cells. In addition, RNA-silenced APP, Tau, and VDAC1 genes in SHSY5Y cells showed reduced levels of H2O2 production, lipid peroxidation, fission-linked GTPase activity, and increased cytochrome oxidase activity and ATP production. These findings suggest that a reduction of human APP, Tau, and VDAC1 may enhance synaptic activity, may improve mitochondrial maintenance and function, and may protect against toxicities of AD-related genes. Thus, these findings also suggest that the reduction of APP, Tau, and VDAC1 mRNA expressions may have therapeutic value for patients with AD.
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Affiliation(s)
- Maria Manczak
- Neurogenetics Laboratory, Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185 Avenue, Beaverton, OR 97006
| | - P. Hemachandra Reddy
- Neurogenetics Laboratory, Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185 Avenue, Beaverton, OR 97006
- Department of Physiology and Pharmacology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239
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234
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Cheng X, Wu J, Geng M, Xiong J. Role of synaptic activity in the regulation of amyloid beta levels in Alzheimer's disease. Neurobiol Aging 2013; 35:1217-32. [PMID: 24368087 DOI: 10.1016/j.neurobiolaging.2013.11.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 11/03/2013] [Accepted: 11/24/2013] [Indexed: 01/27/2023]
Abstract
Alzheimer's disease (AD) is the most common form of dementia. Accumulation of amyloid-beta (Aβ) peptides is regarded as the critical component associated with AD pathogenesis, which is derived from the amyloid precursor protein (APP) cleavage. Recent studies suggest that synaptic activity is one of the most important factors that regulate Aβ levels. It has been found that synaptic activity facilitates APP internalization and influences APP cleavage. Glutamatergic, cholinergic, serotonergic, leptin, adrenergic, orexin, and gamma-amino butyric acid receptors, as well as the activity-regulated cytoskeleton-associated protein (Arc) are all involved in these processes. The present review summarizes the evidence for synaptic activity-modulated Aβ levels and the mechanisms underlying this regulation. Interestingly, the immediate early gene product Arc may also be the downstream signaling molecule of several receptors in the synaptic activity-modulated Aβ levels. Elucidating how Aβ levels are regulated by synaptic activity may provide new insights in both the understanding of the pathogenesis of AD and in the development of therapies to slow down the progression of AD.
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Affiliation(s)
- Xiaofang Cheng
- Department of Physiology, Third Military Medical University, Chongqing, China
| | - Jian Wu
- Department of Physiology, Third Military Medical University, Chongqing, China
| | - Miao Geng
- Institute of Geriatrics, General Hospital of Chinese PLA, Beijing, China
| | - Jiaxiang Xiong
- Department of Physiology, Third Military Medical University, Chongqing, China.
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235
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Perneczky R, Alexopoulos P. Cerebrospinal fluid BACE1 activity and markers of amyloid precursor protein metabolism and axonal degeneration in Alzheimer's disease. Alzheimers Dement 2013; 10:S425-S429.e1. [PMID: 24239250 DOI: 10.1016/j.jalz.2013.09.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 09/13/2013] [Accepted: 09/16/2013] [Indexed: 11/19/2022]
Abstract
OBJECTIVE The objective of this study was to assess cerebrospinal fluid (CSF) β-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1) activity in relation to Alzheimer's disease (AD) and to correlate the enzyme activity with protein markers of APP metabolism and axonal degeneration. METHODS BACE1 activity and protein concentrations were measured and analyzed in 342 participants of the Alzheimer's Disease Neuroimaging Initiative, including 99 normal control, 75 stable mild cognitive impairment (MCI), 87 progressive MCI, and 79 AD dementia cases. All statistical analyses were Bonferroni corrected for multiple comparisons. RESULTS No significant differences between controls and any of the three patient groups were detected for BACE1 activity and soluble APPβ (sAPPβ) concentrations in CSF. Significant correlations with BACE1 activity were found for CSF APPβ and total tau in all four groups and for CSF phosphorylated tau181 in all groups but the progressive MCI group. There were no correlations for CSF amyloid β (Aβ)1-42 or for plasma Aβ1-42 and Aβ1-40. CONCLUSIONS The consistent correlation between BACE1 activity and sAPPβ supports their role as biomarkers of target engagement in clinical trials on BACE1 inhibition.
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Affiliation(s)
- Robert Perneczky
- Neuroepidemiology and Ageing Research Unit, School of Public Health, Faculty of Medicine, The Imperial College of Science, Technology, and Medicine, London, UK; West London Cognitive Disorders Treatment and Research Unit, West London Mental Health Trust, London, UK; Department of Psychiatry and Psychotherapy, Technische Universität München, Munich, Germany.
| | - Panagiotis Alexopoulos
- Department of Psychiatry and Psychotherapy, Technische Universität München, Munich, Germany
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Cecarini V, Bonfili L, Cuccioloni M, Mozzicafreddo M, Rossi G, Keller JN, Angeletti M, Eleuteri AM. Wild type and mutant amyloid precursor proteins influence downstream effects of proteasome and autophagy inhibition. Biochim Biophys Acta Mol Basis Dis 2014; 1842:127-34. [PMID: 24215712 DOI: 10.1016/j.bbadis.2013.11.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 10/09/2013] [Accepted: 11/01/2013] [Indexed: 12/24/2022]
Abstract
Cells rely on complementary proteolytic pathways including the ubiquitin-proteasome system and autophagy to maintain proper protein degradation. There is known to be considerable interplay between them, whereby the loss of one clearance system results in compensatory changes in other proteolytic pathways of the cell. Disturbances in proteolysis are known to occur in Alzheimer's disease, and potentially contribute to neurophysiological and neurodegenerative processes. Currently, few data are available on how the presence of wild type and mutant amyloid precursor protein (APPwt and APPmut) potentially alters the reciprocal interplay between the different intracellular proteolytic pathways. This study used human SH-SY5Y neuronal cell lines, and SH-SY5Y transfected with either APPwt or APPmut (valine-to-glycine substitution at position 717), in order to explore if the presence of APPwt or APPmut altered the downstream effects of pharmacological proteasome or autophagy inhibition. The occurrence of APPwt or APPmut was observed to disturb proteasome or autophagy activities upon treatment with proteasome inhibitors or authophagy inhibitors. Interestingly, APPwt and APPmut expression was observed to significantly and robustly enhance the induction in cathepsin B following the administration of an established proteasome inhibitor. The presence of APPwt and APPmut also significantly reduced the elevation in ubiquitinated proteins following proteasome inhibitor treatments. Our data strongly suggest that APP is able to affect the downstream effects of protease inhibition in neural cells including enhancement of cathepsin B activity, with these changes in cathepsin B significantly and inversely related to the levels of ubiquitinated protein.
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237
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Tanabe F, Nakajima T, Ito M. The thiol proteinase inhibitor E-64-d ameliorates amyloid-β-induced reduction of sAPPα secretion by reversing ceramide-induced protein kinase C down-regulation in SH-SY5Y neuroblastoma cells. Biochem Biophys Res Commun 2013; 441:256-61. [PMID: 24141119 DOI: 10.1016/j.bbrc.2013.10.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 10/10/2013] [Indexed: 10/26/2022]
Abstract
In Alzheimer's disease (AD), enhancing α-secretase processing of amyloid precursor protein (APP) is an important pathway to decrease neurotoxic amyloid β (Aβ) secretion. The α-secretase is reported to be regulated by protein kinase C (PKC) and various endogenous proteins or cell surface receptors. In this report, we first examined whether Aβ reduces α-secretase activity, and showed that Aβ peptide 1-40 (0.001 and 0.01 μM) reduced the secretion of soluble amyloid precursor protein α (sAPPα) in carbachol-stimulated SH-SY5Y neuroblastoma cells. E-64-d (3 μM), which is a potent calpain inhibitor that prevents PKC degradation, ameliorated the Aβ-induced reduction of sAPPα secretion. In addition, we observed that Aβ significantly enhanced ceramide production by activating neutral sphingomyelinase. The cell-permeable ceramide analog, C2-ceramide (1 μg/mL), also reduced sAPPα secretion, and in addition, E-64-d eliminated the observed decrease of sAPPα secretion. C2-ceramide induced down-regulation of PKC-α, -β1, and -β2 isozymes in SH-SY5Y cells. These findings suggest that ceramide may play an important role in sAPPα processing by modulating PKC activity.
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Affiliation(s)
- Fuminori Tanabe
- Department of Human Science, Interdisciplinary Graduate School of Medicine and Engineering, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan.
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238
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Demars MP, Hollands C, Zhao KD(T, Lazarov O. Soluble amyloid precursor protein-α rescues age-linked decline in neural progenitor cell proliferation. Neurobiol Aging 2013; 34:2431-40. [PMID: 23683827 PMCID: PMC3706568 DOI: 10.1016/j.neurobiolaging.2013.04.016] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 03/07/2013] [Accepted: 04/14/2013] [Indexed: 11/30/2022]
Abstract
Neurogenesis is thought to play a role in cognitive function and hippocampal plasticity. Previous studies suggest that neurogenesis declines with aging. However, the onset and mechanism of declined neurogenesis are not fully elucidated. Here we show that the major decline in neurogenesis takes place during adulthood, before aging. Decline in neurogenesis takes place in the subgranular layer of the dentate gyrus and in the subventricular zone, and is primarily due to a reduced number of fast-proliferating neural progenitor cells. Importantly, this decline can be rescued by intraventricular injection of recombinant soluble amyloid precursor protein (sAPPα), which regulates neural progenitor cell proliferation in the adult brain. The counterpart, sAPPβ, a product of the amyloidogenic cleavage pathway of amyloid precursor protein, fails to exhibit a proliferative effect in vitro and in vivo, in equimolar concentrations to sAPPα. These observations suggest that adulthood is an appropriate time window for an intervention that upregulates neurogenesis, such as enhancement of sAPPα levels, for the prevention of declining brain plasticity and cognitive function.
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Affiliation(s)
- Michael P. Demars
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612
| | - Carolyn Hollands
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612
| | - Kai Da (Tommy) Zhao
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612
| | - Orly Lazarov
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612
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239
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Kitazume S, Yoshihisa A, Yamaki T, Oikawa M, Tachida Y, Ogawa K, Imamaki R, Takeishi Y, Yamamoto N, Taniguchi N. Soluble amyloid precursor protein 770 is a novel biomarker candidate for acute coronary syndrome. Proteomics Clin Appl 2013; 7:657-63. [PMID: 23857744 DOI: 10.1002/prca.201200135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 03/08/2013] [Accepted: 04/16/2013] [Indexed: 01/02/2023]
Abstract
Most Alzheimer disease patients show deposition of amyloid β (Aβ) peptide in blood vessels as well as the brain parenchyma. We previously found that vascular endothelial cells express amyloid β precursor protein (APP) 770, a different APP isoform from neuronal APP695, and that they produce amyloid β peptide. We analyzed the glycosylation of APP770 and found that O-glycosylated sAPP770 is preferentially processed by proteases for Aβ production. Because the soluble APP cleavage product sAPP is considered to be a possible marker for Alzheimer disease diagnosis, sAPP, consisting of a mixture of these variants, has been widely measured. We hypothesized that measurement of the endothelial APP770 cleavage product in patients separately from that of neuronal APP695 would enable us to discriminate between endothelial and neurological dysfunctions. Our recent findings, showing that the level of plasma sAPP770 is significantly higher in patients with acute coronary syndrome, raise the possibility that sAPP770 could be an indicator of endothelial dysfunction. In this review, we first describe the expression, glycosylation, and processing of APP770, and then discuss sAPP770 as a novel biomarker candidate of acute coronary syndrome.
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Affiliation(s)
- Shinobu Kitazume
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, Wako, Saitama, Japan.
| | - Akiomi Yoshihisa
- Department of Advanced Cardiac Therapeutics, Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan
| | - Takayoshi Yamaki
- Department of Advanced Cardiac Therapeutics, Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan
| | - Masayoshi Oikawa
- Department of Advanced Cardiac Therapeutics, Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan
| | - Yuriko Tachida
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, Wako, Saitama, Japan
| | - Kazuko Ogawa
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, Wako, Saitama, Japan
| | - Rie Imamaki
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, Wako, Saitama, Japan
| | - Yasuchika Takeishi
- Department of Advanced Cardiac Therapeutics, Cardiology and Hematology, Fukushima Medical University, Fukushima, Japan
| | - Naomasa Yamamoto
- Department of Biochemistry, School of Pharmaceutical Sciences, Ohu University, Tomita, Koriyama, Fukushima, Japan
| | - Naoyuki Taniguchi
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, Wako, Saitama, Japan
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240
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Liang RF, Li WQ, Wang H, Wang JX, Niu Q. Impact of sub-chronic aluminium-maltolate exposure on catabolism of amyloid precursor protein in rats. Biomed Environ Sci 2013; 26:445-452. [PMID: 23816578 DOI: 10.3967/0895-3988.2013.06.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 10/24/2012] [Indexed: 06/02/2023]
Abstract
OBJECTIVE To investigate the impact of sub-chronic Aluminium-maltolate [Al(mal)3] exposure on the catabolism of amyloid precursor protein (APP) in rats. METHODS Forty adult male Sprague-Dawley (SD) rats were randomly divided into five groups: the control group, the maltolate group (7.56 mg/kg BW), and the Al(mal)3 groups (0.27, 0.54, and 1.08 mg/kg BW, respectively). Control rats were administered with 0.9% normal saline through intraperitoneal (i.p.) injection. Maltolate and Al(mal)3 were administered to the rats also through i.p. injections. Administration was conducted daily for two months. Rat neural behavior was examined using open field tests (OFT). And the protein expressions and their mRNAs transcription related with APP catabolism were studied using enzyme-linked immunosorbent assay (ELISA) and real-time polymerase chain reaction (RT-PCR). RESULTS The expressions of APP, β-site APP cleaving enzyme 1 (BACE1) and presenilin-1 (PS1) proteins and their mRNAs transcription increased gradually with the increase of Al(mal)3 doses (P<0.05). The enzyme activity of BACE1 in the 0.54 and 1.08 mg/kg Al(mal)3 groups increased significantly (P<0.05). The expression of β-amyloid protein (Aβ) 1-40 gradually decreased while the protein expression of Aβ1-42 increased gradually with the increase of Al(mal)3 doses (P<0.05). CONCLUSION Result from our study suggested that one of the possible mechanisms that Al(mal)3 can cause neurotoxicity is that Al(mal)3 can increase the generation of Aβ1-42 by facilitating the expressions of APP, β-, and γ-secretase.
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Affiliation(s)
- Rui Feng Liang
- Department of Occupational Health, School of Public Health, Shanxi Medical University, Taiyuan 030001, Shanxi, China
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241
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Trillo L, Das D, Hsieh W, Medina B, Moghadam S, Lin B, Dang V, Sanchez MM, De Miguel Z, Ashford JW, Salehi A. Ascending monoaminergic systems alterations in Alzheimer's disease. translating basic science into clinical care. Neurosci Biobehav Rev 2013; 37:1363-79. [PMID: 23707776 DOI: 10.1016/j.neubiorev.2013.05.008] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 05/13/2013] [Accepted: 05/16/2013] [Indexed: 01/23/2023]
Abstract
Extensive neuropathological studies have established a compelling link between abnormalities in structure and function of subcortical monoaminergic (MA-ergic) systems and the pathophysiology of Alzheimer's disease (AD). The main cell populations of these systems including the locus coeruleus, the raphe nuclei, and the tuberomamillary nucleus undergo significant degeneration in AD, thereby depriving the hippocampal and cortical neurons from their critical modulatory influence. These studies have been complemented by genome wide association studies linking polymorphisms in key genes involved in the MA-ergic systems and particular behavioral abnormalities in AD. Importantly, several recent studies have shown that improvement of the MA-ergic systems can both restore cognitive function and reduce AD-related pathology in animal models of neurodegeneration. This review aims to explore the link between abnormalities in the MA-ergic systems and AD symptomatology as well as the therapeutic strategies targeting these systems. Furthermore, we will examine possible mechanisms behind basic vulnerability of MA-ergic neurons in AD.
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Affiliation(s)
- Ludwig Trillo
- Department of Physiology, School of Medicine, National University of San Agustin, Arequipa, Peru
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242
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Brasnjevic I, Lardenoije R, Schmitz C, Van Der Kolk N, Dickstein DL, Takahashi H, Hof PR, Steinbusch HW, Rutten BP. REGION-SPECIFIC NEURON AND SYNAPSE LOSS IN THE HIPPOCAMPUS OF APP SL/PS1 KNOCK-IN MICE. Transl Neurosci 2013; 4:8-19. [PMID: 24829793 PMCID: PMC4018205 DOI: 10.2478/s13380-013-0111-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Transgenic mouse models with knock-in (KI) expression of human mutant amyloid precursor protein (APP) and/or human presenilin 1 (PS1) may be helpful to elucidate the cellular consequences of APP and PS1 misprocessing in the aging brain. Age-related alterations in total numbers of neurons and in numbers of synaptophysin-immunoreactive presynaptic boutons (SIPB), as well as the amyloid plaque load were analyzed in the hippocampal dentate gyrus (DG), CA3, and CA1-2 of 2- and 10-month-old APPSL/PS1 homozygous KI, APPSL (expressing human mutant APP751 carrying the Swedish [K670N/M671L] and London [V717I] mutations under Thy-1 promoter), and PS1 homozygous KI mice (expressing human PS1 mutations [M233T and L235P]). APPSL/PS1 homozygous KI mice, but neither APPSL mice nor PS1 homozygous KI mice, showed substantial age-related loss of neurons (-47.2%) and SIPB (-22.6%), specifically in CA1-2. PS1 homozygous KI mice showed an age-related increase in hippocampal granule cell numbers (+37.9%). Loss of neurons and SIPB greatly exceeded the amount of local extracellular Aβ aggregation and astrocytes, whereas region-specific accumulation of intraneuronal Aβ preceded neuron and synapse loss. An age-related increase in the ratio of SIPB to neuron numbers in CA1-2 of APPSL/PS1 homozygous KI mice was suggestive of compensatory synaptic plasticity. These findings indicate a region-selectivity in intra- and extraneuronal Aβ accumulation in connection with neuron and synapse loss in the hippocampus of APPSL/PS1 homozygous KI mice.
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Affiliation(s)
- Ivona Brasnjevic
- Department of Psychiatry and Neuropsychology, Maastricht University, 6200 MD Maastricht, The Netherlands
- European Graduate School of Neuroscience (EURON), 6200 MD Maastricht, The Netherlands
| | - Roy Lardenoije
- Department of Psychiatry and Neuropsychology, Maastricht University, 6200 MD Maastricht, The Netherlands
| | - Christoph Schmitz
- Department of Anatomy II, Institute of Anatomy, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Nicolien Van Der Kolk
- Department of Psychiatry and Neuropsychology, Maastricht University, 6200 MD Maastricht, The Netherlands
- European Graduate School of Neuroscience (EURON), 6200 MD Maastricht, The Netherlands
| | - Dara L. Dickstein
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Hisaaki Takahashi
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, 791-0295 Ehime, Japan
| | - Patrick R. Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Harry W.M. Steinbusch
- Department of Psychiatry and Neuropsychology, Maastricht University, 6200 MD Maastricht, The Netherlands
- European Graduate School of Neuroscience (EURON), 6200 MD Maastricht, The Netherlands
| | - Bart P.F. Rutten
- Department of Psychiatry and Neuropsychology, Maastricht University, 6200 MD Maastricht, The Netherlands
- European Graduate School of Neuroscience (EURON), 6200 MD Maastricht, The Netherlands
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243
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Abstract
The search for diagnostic and prognostic markers in Alzheimer’s disease (AD) has been an area of active research in the last decades. Biochemical markers are correlates of intracerebral changes that can be identified in biological fluids, namely: peripheral blood (total blood, red and white blood cells, platelets, plasma and serum), saliva, urine and cerebrospinal fluid. An important feature of a biomarker is that it can be measured objectively and evaluated as (1) an indicator of disease mechanisms (markers of core pathogenic processes or the expression of downstream effects of these processes), or (2) biochemical responses to pharmacological or therapeutic intervention, which can be indicative of disease modification. Platelets have been used in neuropharmacological models since the mid-fifties, as they share several homeostatic functions with neurons, such as accumulation and release of neurotransmitters, responsiveness to variations in calcium concentration, and expression of membrane-bound compounds. Recent studies have shown that platelets also express several components related to the pathogenesis of AD, in particular to the amyloid cascade and the regulation of oxidative stress: thus they can be used in the search for biomarkers of the disease process. For instance, platelets are the most important source of circulating forms of the amyloid precursor protein and other important proteins such as Tau and glycogen synthase kinase-3B. Moreover, platelets express enzymes involved in membrane homeostasis (e.g., phospholipase A2), and markers of the inflammatory process and oxidative stress. In this review we summarize the available literature and discuss evidence concerning the potential use of platelet markers in AD.
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Affiliation(s)
- Leda L Talib
- Leda L Talib, Helena PG Joaquim, Orestes V Forlenza, Laboratory of Neuroscience (LIM-27), Department and Institute of Psychiatry, Faculty of Medicine, University of São Paulo, 05403-010 São Paulo, SP, Brazil
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244
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Abstract
Several parallels exist between platelets and the brain, which make them interesting for studying the neurobiology of psychiatric disorders, such as Alzheimer’s disease, depression, schizophrenia and anxiety disorders. Platelets store, secrete and process the amyloid precursor protein which is cleaved into the β-amyloid (Aβ) peptides. The accumulation of Aβ in brain (plaques) and vessels (Aβ-angiopathy) is a major hallmark in AD. Platelets contain high amounts of serotonin and a dysfunction of the serotoninergic system is involved in the development of several behavior disorders, such as depression, anxiety disorders and self aggressive disturbances. Furthermore, platelets are able to take up dopamine and express various dopamine receptors, which make them to an interesting tool to study the underlying mechanisms of schizophrenia. In summary, platelets are an interesting and easily accessible cell type to study changes related to different psychiatric disorders and platelets proteins may be useful as diagnostic biomarkers for some psychiatric disorders.
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Affiliation(s)
- Daniela Ehrlich
- Daniela Ehrlich, Christian Humpel, Department of Psychiatry and Psychotherapy, Laboratory of Psychiatry and Exp. Alzheimers Research, Anichstr. 35, A-6020 Innsbruck, Austria
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245
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Abstract
Platelets are the first peripheral source of amyloid precursor protein (APP). They possess the proteolytic machinery to produce Aβ and fragments similar to those produced in neurons, and thus offer an ex-vivo model to study APP processing and changes associated with Alzheimer’s disease (AD). Platelet process APP mostly through the α-secretase pathway to release soluble APP (sAPP). They produce small amounts of Aβ, predominantly Aβ40 over Aβ42. sAPP and Aβ are stored in α-granules and are released upon platelet activation by thrombin and collagen, and agents inducing platelet degranulation. A small proportion of full-length APP is present at the platelet surface and this increases by 3-fold upon platelet activation. Immunoblotting of platelet lysates detects APP as isoforms of 130 kDa and 106-110 kDa. The ratio of these of APP isoforms is significantly lower in patients with AD and mild cognitive impairment (MCI) than in healthy controls. This ratio follows a decrease that parallels cognitive decline and can predict conversion from MCI to AD. Alterations in the levels of α-secretase ADAM10 and in the enzymatic activities of α- and β-secretase observed in platelets of patients with AD are consistent with increased processing through the amyloidogenic pathway. β-APP cleaving enzyme activity is increased by 24% in platelet membranes of patients with MCI and by 17% in those with AD. Reports of changes in platelet APP expression with MCI and AD have been promising so far and merit further investigation as the search for blood biomarkers in AD, in particular at the prodromal stage, remains a priority and a challenge.
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Affiliation(s)
- Geneviève Evin
- Geneviève Evin, Qiao-Xin Li, Department of Pathology and Mental Health Research Institute, The University of Melbourne, Parkville 3010, Australia
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246
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Ringman JM, Tomic JL, Coppola G, Elashoff D, Gylys KH, Glabe CG. Conformation-dependent oligomers in cerebrospinal fluid of presymptomatic familial Alzheimer's disease mutation carriers. Dement Geriatr Cogn Dis Extra 2012; 2:652-7. [PMID: 23341831 PMCID: PMC3551434 DOI: 10.1159/000345771] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Background/Aims Oligomerization of amyloid beta (Aβ) is a hypothesized step in the formation of plaques in Alzheimer's disease (AD) but has been difficult to demonstrate in vivo in humans. As persons destined to develop familial AD (FAD) due to fully penetrant autosomal dominant mutations are essentially certain to develop the disease, they provide the opportunity to identify oligomers during the presymptomatic stage of the disease. Methods We measured levels of Aβ42 using a conventional immunoassay and prefibrillar, fibrillar, and annular protofibrillar oligomers using polyclonal conformation-dependent antibodies in the cerebrospinal fluid (CSF) of 7 persons at risk for inheriting FAD mutations. Levels of oligomers were compared between FAD mutation carriers and noncarriers. Results Compared to 2 noncarriers, annular protofibrillar oligomers were elevated, prefibrillar and fibrillar oligomers trended towards elevation and Aβ42 monomer trended towards being decreased in 5 FAD mutation carriers. Conclusion Our data provide evidence for an identifiable elevation of CSF oligomers during the presymptomatic phase of FAD.
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Affiliation(s)
- John M Ringman
- Mary S. Easton Center for Alzheimer's Disease Research at UCLA, Calif., USA
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247
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Ladd AN. CUG-BP, Elav-like family (CELF)-mediated alternative splicing regulation in the brain during health and disease. Mol Cell Neurosci 2012; 56:456-64. [PMID: 23247071 DOI: 10.1016/j.mcn.2012.12.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 12/01/2012] [Accepted: 12/06/2012] [Indexed: 11/27/2022] Open
Abstract
Alternative splicing is an important mechanism for generating transcript and protein diversity. In the brain, alternative splicing is particularly prevalent, and alternative splicing factors are highly enriched. These include the six members of the CUG-BP, Elav-like family (CELF). This review summarizes what is known about the expression of different CELF proteins in the nervous system and the evidence that they are important in neural development and function. The involvement of CELF proteins in the pathogenesis of a number of neurodegenerative disorders, including myotonic dystrophy, spinocerebellar ataxia, fragile X syndrome, spinal muscular atrophy, and spinal and bulbar muscular atrophy is discussed. Finally, the known targets of CELF-mediated alternative splicing regulation in the nervous system and the functional consequences of these splicing events are reviewed. This article is part of a Special Issue entitled "RNA and splicing regulation in neurodegeneration."
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Affiliation(s)
- Andrea N Ladd
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.
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248
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Colombo A, Wang H, Kuhn PH, Page R, Kremmer E, Dempsey PJ, Crawford HC, Lichtenthaler SF. Constitutive α- and β-secretase cleavages of the amyloid precursor protein are partially coupled in neurons, but not in frequently used cell lines. Neurobiol Dis 2013; 49:137-47. [PMID: 22940630 DOI: 10.1016/j.nbd.2012.08.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2012] [Revised: 07/20/2012] [Accepted: 08/16/2012] [Indexed: 11/21/2022] Open
Abstract
Proteolytic cleavage of the amyloid precursor protein (APP) by the two proteases α- and β-secretases controls the generation of the amyloid β peptide (Aβ), a key player in Alzheimer's disease pathogenesis. The α-secretase ADAM10 and the β-secretase BACE1 have opposite effects on Aβ generation and are assumed to compete for APP as a substrate, such that their cleavages are inversely coupled. This concept was mainly demonstrated in studies using activation or overexpression of α- and β-secretases. Here, we report that this inverse coupling is not seen to the same extent upon inhibition of the endogenous proteases. Genetic and pharmacological inhibition of ADAM10 and BACE1 revealed that the endogenous, constitutive α-secretase cleavage of APP is largely uncoupled from β-secretase cleavage and Aβ generation in neuroglioma H4 cells and in neuronally differentiated SH-SY5Y cells. In contrast, inverse coupling was observed in primary cortical neurons. However, this coupling was not bidirectional. Inhibition of BACE1 increased ADAM10 cleavage of APP, but a reduction of ADAM10 activity did not increase the BACE1 cleavage of APP in the neurons. Our analysis shows that the inverse coupling of the endogenous α- and β-secretase cleavages depends on the cellular model and suggests that a reduction of ADAM10 activity is unlikely to increase the AD risk through increased β-secretase cleavage.
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249
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Mackinnon JC, Huether P, Kalisch BE. Effects of nerve growth factor and nitric oxide synthase inhibitors on amyloid precursor protein mRNA levels and protein stability. Open Biochem J 2012; 6:31-9. [PMID: 22550546 PMCID: PMC3339428 DOI: 10.2174/1874091x01206010031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 01/05/2012] [Accepted: 01/10/2012] [Indexed: 12/25/2022] Open
Abstract
We determined previously that nitric oxide (NO) modulates the nerve growth factor (NGF)-mediated increases in amyloid precursor protein (APP) levels in PC12 cells. To elucidate potential mechanisms, the effects of NGF and NO synthase (NOS) inhibitors on APP mRNA levels and protein stability were evaluated. Surprisingly, treatment of PC12 cells with NGF resulted in decreased levels of APP695 and APP751/770 mRNA. Therefore, the effect of NGF on APP protein stability was examined using the translation inhibitor, cycloheximide. Under these conditions, NGF did not alter the rate of APP degradation, suggesting that NGF may be enhancing the translation rate of APP. Since NOS inhibitors attenuate the NGF-mediated increase in APP levels, their effect on APP mRNA levels and protein stability was also assessed. S-methylisothiourea (S-MIU), selective for inducible NOS, decreased both APP695 and APP751/770 mRNA levels while the non-selective NOS inhibitor, N(ω)-nitro-L-arginine methylester (L-NAME) had no effect. In both control and NGF-treated PC12 cells, S-MIU increased the half-life of APP, with the greatest effect observed with the APP695 isoform. Based on these data we propose that in PC12 cells, NGF increases APP levels through enhanced translation rate and that NO, which modulates the NGF-induced increase in APP protein, also regulates APP mRNA levels and could play a role in APP processing.
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Affiliation(s)
- Janet C Mackinnon
- Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
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250
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Malm T, Magga J, Koistinaho J. Animal Models of Alzheimer's Disease: Utilization of Transgenic Alzheimer's Disease Models in Studies of Amyloid Beta Clearance. ACTA ACUST UNITED AC 2012; 1:11-20. [PMID: 23440676 DOI: 10.1007/s13670-011-0004-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Glial cells in Alzheimer’s disease (AD) have been shown to be capable of clearing or at least restricting the accumulation of toxic amyloid beta (Aβ) deposits. Recently, bone marrow (BM)–derived monocytic cells have been recognized in experimental studies to be superior in their phagocytic properties when compared to their brain endogenous counterparts. In human AD, BM-derived monocytic cells may have deficiencies in their capacity to restrict plaque growth. Therefore, enhancement of phagocytic properties of cells of monocyte origin, both brain endogenous microglia and BM-derived monocytic cells, offers an attractive therapeutic approach to fight off AD. Transgenic mouse models with aberrant Aβ deposition offer a valuable tool for discovery of novel pathways to facilitate cell-mediated Aβ uptake. This article reviews the most recent findings on the phagocytic capacity of cells with monocytic origin in various transgenic AD models and describes the methods to study phagocytic activity of these cells.
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