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Patel AG, Nehete PN, Krivoshik SR, Pei X, Cho EL, Nehete BP, Ramani MD, Shao Y, Williams LE, Wisniewski T, Scholtzova H. Innate immunity stimulation via CpG oligodeoxynucleotides ameliorates Alzheimer's disease pathology in aged squirrel monkeys. Brain 2021; 144:2146-2165. [PMID: 34128045 PMCID: PMC8502485 DOI: 10.1093/brain/awab129] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 12/09/2020] [Accepted: 12/17/2020] [Indexed: 11/15/2022] Open
Abstract
Alzheimer's disease is the most common cause of dementia and the only illness among the top 10 causes of death for which there is no disease-modifying therapy. The failure rate of clinical trials is very high, in part due to the premature translation of successful results in transgenic mouse models to patients. Extensive evidence suggests that dysregulation of innate immunity and microglia/macrophages plays a key role in Alzheimer's disease pathogenesis. Activated resident microglia and peripheral macrophages can display protective or detrimental phenotypes depending on the stimulus and environment. Toll-like receptors (TLRs) are a family of innate immune regulators known to play an important role in governing the phenotypic status of microglia. We have shown in multiple transgenic Alzheimer's disease mouse models that harnessing innate immunity via TLR9 agonist CpG oligodeoxynucleotides (ODNs) modulates age-related defects associated with immune cells and safely reduces amyloid plaques, oligomeric amyloid-β, tau pathology, and cerebral amyloid angiopathy (CAA) while promoting cognitive benefits. In the current study we have used a non-human primate model of sporadic Alzheimer's disease pathology that develops extensive CAA-elderly squirrel monkeys. The major complications in current immunotherapeutic trials for Alzheimer's disease are amyloid-related imaging abnormalities, which are linked to the presence and extent of CAA; hence, the prominence of CAA in elderly squirrel monkeys makes them a valuable model for studying the safety of the CpG ODN-based concept of immunomodulation. We demonstrate that long-term use of Class B CpG ODN 2006 induces a favourable degree of innate immunity stimulation without producing excessive or sustained inflammation, resulting in efficient amelioration of both CAA and tau Alzheimer's disease-related pathologies in association with behavioural improvements and in the absence of microhaemorrhages in aged elderly squirrel monkeys. CpG ODN 2006 has been well established in numerous human trials for a variety of diseases. The present evidence together with our earlier, extensive preclinical research, validates the beneficial therapeutic outcomes and safety of this innovative immunomodulatory approach, increasing the likelihood of CpG ODN therapeutic efficacy in future clinical trials.
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Affiliation(s)
- Akash G Patel
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
| | - Pramod N Nehete
- Department of Comparative Medicine, the University of Texas MD Anderson Cancer Center, Bastrop, TX 78602, USA
- The University of Texas Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Sara R Krivoshik
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
| | - Xuewei Pei
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
| | - Elizabeth L Cho
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
| | - Bharti P Nehete
- Department of Comparative Medicine, the University of Texas MD Anderson Cancer Center, Bastrop, TX 78602, USA
| | - Margish D Ramani
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
| | - Yongzhao Shao
- Division of Biostatistics, Departments of Population Health and Environmental Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Lawrence E Williams
- Department of Comparative Medicine, the University of Texas MD Anderson Cancer Center, Bastrop, TX 78602, USA
| | - Thomas Wisniewski
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
- Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA
| | - Henrieta Scholtzova
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, New York, NY 10016, USA
- Department of Comparative Medicine, the University of Texas MD Anderson Cancer Center, Bastrop, TX 78602, USA
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Montoliu-Gaya L, Strydom A, Blennow K, Zetterberg H, Ashton NJ. Blood Biomarkers for Alzheimer's Disease in Down Syndrome. J Clin Med 2021; 10:3639. [PMID: 34441934 PMCID: PMC8397053 DOI: 10.3390/jcm10163639] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/09/2021] [Accepted: 08/12/2021] [Indexed: 12/15/2022] Open
Abstract
Epidemiological evidence suggests that by the age of 40 years, all individuals with Down syndrome (DS) have Alzheimer's disease (AD) neuropathology. Clinical diagnosis of dementia by cognitive assessment is complex in these patients due to the pre-existing and varying intellectual disability, which may mask subtle declines in cognitive functioning. Cerebrospinal fluid (CSF) and positron emission tomography (PET) biomarkers, although accurate, are expensive, invasive, and particularly challenging in such a vulnerable population. The advances in ultra-sensitive detection methods have highlighted blood biomarkers as a valuable and realistic tool for AD diagnosis. Studies with DS patients have proven the potential blood-based biomarkers for sporadic AD (amyloid-β, tau, phosphorylated tau, and neurofilament light chain) to be useful in this population. In addition, biomarkers related to other pathologies that could aggravate dementia progression-such as inflammatory dysregulation, energetic imbalance, or oxidative stress-have been explored. This review serves to provide a brief overview of the main findings from the limited neuroimaging and CSF studies, outline the current state of blood biomarkers to diagnose AD in patients with DS, discuss possible past limitations of the research, and suggest considerations for developing and validating blood-based biomarkers in the future.
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Affiliation(s)
- Laia Montoliu-Gaya
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, The Sahlgrenska Academy at the University of Gothenburg, 431 41 Mölndal, Sweden; (K.B.); (H.Z.); (N.J.A.)
| | - Andre Strydom
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London WC2R 2LS, UK;
- South London and Maudsley NHS Foundation Trust, London SE5 8AZ, UK
- London Down Syndrome Consortium (LonDowns), London, UK
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, The Sahlgrenska Academy at the University of Gothenburg, 431 41 Mölndal, Sweden; (K.B.); (H.Z.); (N.J.A.)
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, 413 45 Mölndal, Sweden
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, The Sahlgrenska Academy at the University of Gothenburg, 431 41 Mölndal, Sweden; (K.B.); (H.Z.); (N.J.A.)
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, 413 45 Mölndal, Sweden
- Department of Neurodegenerative Disease, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
- UK Dementia Research Institute, University College London, London WC1E 6BT, UK
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
| | - Nicholas James Ashton
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, The Sahlgrenska Academy at the University of Gothenburg, 431 41 Mölndal, Sweden; (K.B.); (H.Z.); (N.J.A.)
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden
- Department of Old Age Psychiatry, Maurice Wohl Clinical Neuroscience Institute, King’s College London, London SE5 9RT, UK
- NIHR Biomedical Research Centre for Mental Health, Biomedical Research Unit for Dementia at South London, Maudsley NHS Foundation, London SE5 8AF, UK
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Yang YH, Situmeang RFV, Ong PA. Can blood amyloid levels be used as a biomarker for Alzheimer’s disease? BRAIN SCIENCE ADVANCES 2021. [DOI: 10.26599/bsa.2021.9050004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Alzheimer’s disease (AD) increasingly affects society due to aging populations. Even at pre‐clinical stages, earlier and accurate diagnoses are essential for optimal AD management and improved clinical outcomes. Biomarkers such as beta‐amyloid (Aβ) or tau protein in cerebrospinal fluid (CSF) have been used as reliable markers to distinguish AD from non‐AD, and predicting clinical outcomes, to attain these goals. However, given CSF access methods’ invasiveness, these biomarkers are not used extensively in clinical settings. Blood Aβ has been proposed as an alternative biomarker since it is less invasive than CSF; however, sampling heterogeneity has limited its clinical applicability. In this review, we investigated blood Aβ as a biomarker in AD and explored how Aβ can be facilitated as a viable biomarker for successful AD management.
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Affiliation(s)
- Yuan-Han Yang
- Department of Neurology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan, China
- Department of Neurology, Kaohsiung Municipal Ta‐Tung Hospital, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, China
- Neuroscience Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan, China
| | - Rocksy FV Situmeang
- Siloam Hospitals Lippo Village, Pelita Harapan University, Banten, Indonesia
| | - Paulus Anam Ong
- Department of Neurology, Hasan Sadikin Hospital, Bandung, Indonesia
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Du Y, Chen L, Jiao Y, Cheng Y. Cerebrospinal fluid and blood Aβ levels in Down syndrome patients with and without dementia: a meta-analysis study. Aging (Albany NY) 2019; 11:12202-12212. [PMID: 31860872 PMCID: PMC6949072 DOI: 10.18632/aging.102560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 11/20/2019] [Indexed: 12/30/2022]
Abstract
Abnormal β-amyloid (Aβ) levels were found in patients with Down syndrome (DS). However, Aβ levels in patients with DS and DS with dementia (DSD) vary considerably across studies. Therefore, we performed a systematic literature review and quantitatively summarized the clinical Aβ data on the cerebrospinal fluid (CSF) and blood of patients with DS and those with DSD using a meta-analytical technique. We performed a systematic search of the PubMed and Web of Science and identified 27 studies for inclusion in the meta-analysis. Random-effects meta-analysis indicated that the levels of blood Aβ1-40 and Aβ1-42 were significantly elevated in patients with DS compared with those in healthy control (HC) subjects. In contrast, there were no significant differences between patients with DS and those with DSD in the blood Aβ1-40 and Aβ1-42 levels. The CSF Aβ1-42 levels were significantly decreased in patients with DS compared to those in HC subjects. Further, CSF Aβ1-42 levels were significantly decreased in patients with DSD compared to those with DS, with a large effect size. Taken together, our results demonstrated that blood Aβ1-40 and Aβ1-42 levels were significantly increased in patients with DS while CSF Aβ1-42, but not Aβ1-40 levels were significantly decreased in patients with DS.
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Affiliation(s)
- Yang Du
- Center on Translational Neuroscience, College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Lei Chen
- Center on Translational Neuroscience, College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Yuguo Jiao
- Center on Translational Neuroscience, College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Yong Cheng
- Center on Translational Neuroscience, College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
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Plasma Aβ42 and Total Tau Predict Cognitive Decline in Amnestic Mild Cognitive Impairment. Sci Rep 2019; 9:13984. [PMID: 31562355 PMCID: PMC6764975 DOI: 10.1038/s41598-019-50315-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 09/04/2019] [Indexed: 01/21/2023] Open
Abstract
Levels of amyloid-β (Aβ) and tau peptides in brain have been associated with Alzheimer disease (AD). The current study investigated the abilities of plasma Aβ42 and total-tau (t-tau) levels in predicting cognitive decline in subjects with amnestic mild cognitive impairment (MCI). Plasma Aβ42 and t-tau levels were quantified in 22 participants with amnestic MCI through immunomagnetic reduction (IMR) assay at baseline. The cognitive performance of participants was measured through neuropsychological tests at baseline and annual follow-up (average follow-up period of 1.5 years). The predictive value of plasma Aβ42 and t-tau for cognitive status was evaluated. We found that higher levels of Aβ42 and t-tau are associated with lower episodic verbal memory performance at baseline and cognitive decline over the course of follow-up. While Aβ42 or t-tau alone had moderate-to-high discriminatory value in the identification of future cognitive decline, the product of Aβ42 and t-tau offered greater differential value. These preliminary results might suggest that high levels of plasma Aβ42 and t-tau in amnestic MCI are associated with later cognitive decline. A further replication with a larger sample over a longer time period to validate and determine their long-term predictive value is warranted.
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Alhajraf F, Ness D, Hye A, Strydom A. Plasma amyloid and tau as dementia biomarkers in Down syndrome: Systematic review and meta-analyses. Dev Neurobiol 2019; 79:684-698. [PMID: 31389176 PMCID: PMC6790908 DOI: 10.1002/dneu.22715] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 08/02/2019] [Accepted: 08/02/2019] [Indexed: 12/18/2022]
Abstract
Individuals with Down syndrome (DS) are at high risk of developing Alzheimer's disease (AD). Discovering reliable biomarkers which could facilitate early AD diagnosis and be used to predict/monitor disease course would be extremely valuable. To examine if analytes in blood related to amyloid plaques may constitute such biomarkers, we conducted meta‐analyses of studies comparing plasma amyloid beta (Aβ) levels between DS individuals and controls, and between DS individuals with and without dementia. PubMed, Embase, and Google Scholar were searched for studies investigating the relationship between Aβ plasma concentrations and dementia in DS and 10 studies collectively comprising >1,600 adults, including >1,400 individuals with DS, were included. RevMan 5.3 was used to perform meta‐analyses. Meta‐analyses showed higher plasma Aβ40 (SMD = 1.79, 95% CI [1.14, 2.44], Z = 5.40, p < .00001) and plasma Aβ42 levels (SMD = 1.41, 95% CI [1.15, 1.68], Z = 10.46, p < .00001) in DS individuals than controls, and revealed that DS individuals with dementia had higher plasma Aβ40 levels (SMD = 0.23, 95% CI [0.05, 0.41], Z = 2.54, p = .01) and lower Aβ42/Aβ40 ratios (SMD = −0.33, 95% CI [−0.63, −0.03], Z = 2.15, p = .03) than DS individuals without dementia. Our results indicate that plasma Aβ40 levels may constitute a promising biomarker for predicting dementia status in individuals with DS. Further investigations using new ultra‐sensitive assays are required to obtain more reliable results and to investigate to what extent these results may be generalizable beyond the DS population.
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Affiliation(s)
- Falah Alhajraf
- UCL Queen Square Institute of Neurology, University College London, London, UK.,Al Amiri Hospital, Kuwait City, State of Kuwait
| | - Deborah Ness
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,The LonDownS Consortium (London Down Syndrome Consortium), London, UK
| | - Abdul Hye
- The Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Andre Strydom
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,The LonDownS Consortium (London Down Syndrome Consortium), London, UK
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Hamlett ED, LaRosa A, Mufson EJ, Fortea J, Ledreux A, Granholm AC. Exosome release and cargo in Down syndrome. Dev Neurobiol 2019; 79:639-655. [PMID: 31347291 DOI: 10.1002/dneu.22712] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 07/20/2019] [Accepted: 07/22/2019] [Indexed: 12/11/2022]
Abstract
Down syndrome (DS) is a multisystem disorder affecting 1 in 800 births worldwide. Advancing technology, medical treatment, and social intervention have dramatically increased life expectancy, yet there are many etiologies of this disorder that are in need of further research. The advent of the ability to capture extracellular vesicles (EVs) in blood from specific cell types allows for the investigation of novel intracellular processes. Exosomes are one type of EVs that have demonstrated great potential in uncovering new biomarkers of neurodegeneration and disease, and also that appear to be intricately involved in the transsynaptic spread of pathogenic factors underlying Alzheimer's disease and other neurological diseases. Exosomes are nanosized vesicles, generated in endosomal multivesicular bodies (MVBs) and secreted by most cells in the body. Since exosomes are important mediators of intercellular communication and genetic exchange, they have emerged as a major research focus and have revealed novel biological sequelae involved in conditions afflicting the DS population. This review summarizes current knowledge on exosome biology in individuals with DS, both early in life and in aging individuals. Collectively these studies have demonstrated that complex multicellular processes underlying DS etiologies may include abnormal formation and secretion of extracellular vesicles such as exosomes.
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Affiliation(s)
- Eric D Hamlett
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina
| | - Angela LaRosa
- Department of Pediatrics, Medical University of South Carolina, Charleston, South Carolina
| | - Elliott J Mufson
- Department of Neurobiology and Neurology, Barrow Neurological Institute, Phoenix, Arizona
| | - Juan Fortea
- Memory Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, Biomedical Research Institute Sant Pau, CIBERNED, Universitat Autònoma de Barcelona, Barcelona, Spain.,Alzheimer's Disease and Other Cognitive Disorders Unit, Department of Neurology, Hospital Clínic, Institut d'Investigació Biomèdica August Pi i Sunyer, University of Barcelona, Barcelona, Spain
| | - Aurélie Ledreux
- Department of Biological Sciences and the Knoebel Institute for Healthy Aging, University of Denver, Denver, Colorado
| | - Ann-Charlotte Granholm
- Department of Biological Sciences and the Knoebel Institute for Healthy Aging, University of Denver, Denver, Colorado
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Startin CM, Ashton NJ, Hamburg S, Hithersay R, Wiseman FK, Mok KY, Hardy J, Lleó A, Lovestone S, Parnetti L, Zetterberg H, Hye A, Strydom A. Plasma biomarkers for amyloid, tau, and cytokines in Down syndrome and sporadic Alzheimer's disease. Alzheimers Res Ther 2019; 11:26. [PMID: 30902060 PMCID: PMC6429702 DOI: 10.1186/s13195-019-0477-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 02/21/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND Down syndrome (DS), caused by chromosome 21 trisomy, is associated with an ultra-high risk of dementia due to Alzheimer's disease (AD), driven by amyloid precursor protein (APP) gene triplication. Understanding relevant molecular differences between those with DS, those with sporadic AD (sAD) without DS, and controls will aid in understanding AD development in DS. We explored group differences in plasma concentrations of amyloid-β peptides and tau (as their accumulation is a characteristic feature of AD) and cytokines (as the inflammatory response has been implicated in AD development, and immune dysfunction is common in DS). METHODS We used ultrasensitive assays to compare plasma concentrations of the amyloid-β peptides Aβ40 and Aβ42, total tau (t-tau), and the cytokines IL1β, IL10, IL6, and TNFα between adults with DS (n = 31), adults with sAD (n = 27), and controls age-matched to the group with DS (n = 27), and explored relationships between molecular concentrations and with age within each group. In the group with DS, we also explored relationships with neurofilament light (NfL) concentration, due to its potential use as a biomarker for AD in DS. RESULTS Aβ40, Aβ42, and IL1β concentrations were higher in DS, with a higher Aβ42/Aβ40 ratio in controls. The group with DS showed moderate positive associations between concentrations of t-tau and both Aβ42 and IL1β. Only NfL concentration in the group with DS showed a significant positive association with age. CONCLUSIONS Concentrations of Aβ40 and Aβ42 were much higher in adults with DS than in other groups, reflecting APP gene triplication, while no difference in the Aβ42/Aβ40 ratio between those with DS and sAD may indicate similar processing and deposition of Aβ40 and Aβ42 in these groups. Higher concentrations of IL1β in DS may reflect an increased vulnerability to infections and/or an increased prevalence of autoimmune disorders, while the positive association between IL1β and t-tau in DS may indicate IL1β is associated with neurodegeneration. Finally, NfL concentration may be the most suitable biomarker for dementia progression in DS. The identification of such a biomarker is important to improve the detection of dementia and monitor its progression, and for designing clinical intervention studies.
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Affiliation(s)
- Carla M. Startin
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, 16 De Crespigny Park, London, SE5 8AF UK
- Division of Psychiatry, University College London, London, UK
- The LonDownS Consortium (London Down Syndrome Consortium), London, UK
| | - Nicholas J. Ashton
- Maurice Wohl Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
- NIHR Biomedical Research Centre for Mental Health, Biomedical Research Unit for Dementia at South London, and Maudsley NHS Foundation, London, UK
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Wallenberg Centre for Molecular & Translational Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Sarah Hamburg
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, 16 De Crespigny Park, London, SE5 8AF UK
- Division of Psychiatry, University College London, London, UK
- The LonDownS Consortium (London Down Syndrome Consortium), London, UK
| | - Rosalyn Hithersay
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, 16 De Crespigny Park, London, SE5 8AF UK
- Division of Psychiatry, University College London, London, UK
- The LonDownS Consortium (London Down Syndrome Consortium), London, UK
| | - Frances K. Wiseman
- The LonDownS Consortium (London Down Syndrome Consortium), London, UK
- Department of Neurodegenerative Disease, Institute of Neurology, University College London, London, UK
| | - Kin Y. Mok
- The LonDownS Consortium (London Down Syndrome Consortium), London, UK
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, SAR People’s Republic of China
| | - John Hardy
- The LonDownS Consortium (London Down Syndrome Consortium), London, UK
- Department of Molecular Neuroscience, Institute of Neurology, University College London, London, UK
- Reta Lila Weston Institute, Institute of Neurology, University College London, London, UK
| | - Alberto Lleó
- Memory Unit, Neurology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | | | - Lucilla Parnetti
- Centre for Memory Disturbances, Laboratory of Clinical Neurochemistry, Section of Neurology, Department of Medicine, University of Perugia, Perugia, Italy
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Department of Neurodegenerative Disease, Institute of Neurology, University College London, London, UK
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
- UK Dementia Research Institute at UCL, London, UK
| | - Abdul Hye
- Maurice Wohl Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
- NIHR Biomedical Research Centre for Mental Health, Biomedical Research Unit for Dementia at South London, and Maudsley NHS Foundation, London, UK
| | - André Strydom
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, 16 De Crespigny Park, London, SE5 8AF UK
- Division of Psychiatry, University College London, London, UK
- The LonDownS Consortium (London Down Syndrome Consortium), London, UK
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9
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Lee JH, Lee AJ, Dang LH, Pang D, Kisselev S, Krinsky-McHale SJ, Zigman WB, Luchsinger JA, Silverman W, Tycko B, Clark LN, Schupf N. Candidate gene analysis for Alzheimer's disease in adults with Down syndrome. Neurobiol Aging 2017; 56:150-158. [PMID: 28554490 DOI: 10.1016/j.neurobiolaging.2017.04.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 03/17/2017] [Accepted: 04/21/2017] [Indexed: 11/16/2022]
Abstract
Individuals with Down syndrome (DS) overexpress many genes on chromosome 21 due to trisomy and have high risk of dementia due to the Alzheimer's disease (AD) neuropathology. However, there is a wide range of phenotypic differences (e.g., age at onset of AD, amyloid β levels) among adults with DS, suggesting the importance of factors that modify risk within this particularly vulnerable population, including genotypic variability. Previous genetic studies in the general population have identified multiple genes that are associated with AD. This study examined the contribution of polymorphisms in these genes to the risk of AD in adults with DS ranging from 30 to 78 years of age at study entry (N = 320). We used multiple logistic regressions to estimate the likelihood of AD using single-nucleotide polymorphisms (SNPs) in candidate genes, adjusting for age, sex, race/ethnicity, level of intellectual disability and APOE genotype. This study identified multiple SNPs in APP and CST3 that were associated with AD at a gene-wise level empirical p-value of 0.05, with odds ratios in the range of 1.5-2. SNPs in MARK4 were marginally associated with AD. CST3 and MARK4 may contribute to our understanding of potential mechanisms where CST3 may contribute to the amyloid pathway by inhibiting plaque formation, and MARK4 may contribute to the regulation of the transition between stable and dynamic microtubules.
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Affiliation(s)
- Joseph H Lee
- Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Taub Institute, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Epidemiology, School of Public Health, Columbia University, New York, NY, USA.
| | - Annie J Lee
- Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Lam-Ha Dang
- Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Epidemiology, School of Public Health, Columbia University, New York, NY, USA
| | - Deborah Pang
- Department of Psychology, NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - Sergey Kisselev
- Department of Pathology & Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Sharon J Krinsky-McHale
- Department of Psychology, NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - Warren B Zigman
- Department of Psychology, NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - José A Luchsinger
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Wayne Silverman
- Kennedy Krieger Institute and Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Benjamin Tycko
- Department of Pathology & Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Lorraine N Clark
- Taub Institute, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Pathology & Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Nicole Schupf
- Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Taub Institute, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Epidemiology, School of Public Health, Columbia University, New York, NY, USA
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Doran E, Keator D, Head E, Phelan MJ, Kim R, Totoiu M, Barrio JR, Small GW, Potkin SG, Lott IT. Down Syndrome, Partial Trisomy 21, and Absence of Alzheimer's Disease: The Role of APP. J Alzheimers Dis 2017; 56:459-470. [PMID: 27983553 PMCID: PMC5662115 DOI: 10.3233/jad-160836] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Overexpression of the amyloid precursor protein (APP) gene on chromosome 21 in Down syndrome (DS) has been linked to increased brain amyloid levels and early-onset Alzheimer's disease (AD). An elderly man with phenotypic DS and partial trisomy of chromosome 21 (PT21) lacked triplication of APP affording an opportunity to study the role of this gene in the pathogenesis of dementia. Multidisciplinary studies between ages 66-72 years comprised neuropsychological testing, independent neurological exams, amyloid PET imaging with 11C-Pittsburgh compound-B (PiB), plasma amyloid-β (Aβ) measurements, and a brain autopsy examination. The clinical phenotype was typical for DS and his intellectual disability was mild in severity. His serial neuropsychological test scores showed less than a 3% decline as compared to high functioning individuals with DS who developed dementia wherein the scores declined 17-28% per year. No dementia was detected on neurological examinations. On PiB-PET scans, the patient with PT21 had lower PiB standard uptake values than controls with typical DS or sporadic AD. Plasma Aβ42 was lower than values for demented or non-demented adults with DS. Neuropathological findings showed only a single neuritic plaque and neurofibrillary degeneration consistent with normal aging but not AD. Taken together the findings in this rare patient with PT21 confirm the obligatory role of APP in the clinical, biochemical, and neuropathological findings of AD in DS.
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Affiliation(s)
- Eric Doran
- Department of Pediatrics, University of California, Irvine, Orange, CA, USA
| | - David Keator
- Department of Psychiatry and Human Behavior, University of California, Irvine, CA, USA
| | - Elizabeth Head
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA
| | - Michael J. Phelan
- Department of Statistics, University of California, Irvine, Irvine, CA, USA
| | - Ron Kim
- Department of Pathology, University of California, Irvine, Orange, CA, USA
| | - Minodora Totoiu
- Department of Pediatrics, University of California, Irvine, Orange, CA, USA
| | - Jorge R. Barrio
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
| | - Gary W. Small
- Department of Psychiatry and Biobehavioral Sciences and the Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA
| | - Steven G. Potkin
- Department of Psychiatry and Human Behavior, University of California, Irvine, CA, USA
| | - Ira T. Lott
- Department of Pediatrics, University of California, Irvine, Orange, CA, USA,Corresponding author: Ira T. Lott, MD, Address: University of California, Irvine Medical Center, 101 The City Drive South, ZC 4482, Orange, CA 92868, Phone: 714-456-5333, Fax: 714-456-8466,
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11
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Mehta PD, Patrick BA, Barshatzky M, Mehta SP, Frackowiak J, Mazur-Kolecka B, Miller DL. Generation of Rabbit Monoclonal Antibody to Amyloid-β38 (Aβ38): Increased Plasma Aβ38 Levels in Down Syndrome. J Alzheimers Dis 2016; 46:1021-32. [PMID: 26402629 DOI: 10.3233/jad-142592] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Secreted soluble amyloid-β (Aβ)38 is the second most prominent Aβ form next to Aβ40, and is found in cerebrospinal fluid (CSF) and blood. Recent studies have shown the importance of quantitation of CSF Aβ38 levels in combination with those of Aβ40 and Aβ42 to support the diagnosis of Alzheimer's disease (AD), and other neurodegenerative diseases, and to facilitate drug discovery studies. However, the availability of reliable and specific Aβ38 monoclonal antibody is limited. Our first aim was to generate and partially characterize rabbit monoclonal antibody (RabmAb) to Aβ38. The antibody was specific to Aβ38, since it did not react with Aβ37, Aβ39, Aβ40, or Aβ42 in ELISA or immunoblotting. The antibody was sensitive enough to measure Aβ38 levels in plasma. Our second aim was to quantitate Aβ38 levels in plasma from older Down syndrome (DS) persons and age-matched controls. Persons with DS (35 years and older) have neuropathological changes characteristic of AD. Studies have shown that plasma Aβ40 and Aβ42 levels are higher in older persons with DS than in controls. However, none examined Aβ38 levels in DS. Our quantitation data showed that, like Aβ40 and Aβ42 plasma levels, Aβ38 plasma levels were higher in DS than in controls. Longitudinal studies will determine whether plasma Aβ38 levels in combination with levels of Aβ40 and Aβ42 are useful to predict early signs of AD in DS.
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12
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Head E, Lott IT, Wilcock DM, Lemere CA. Aging in Down Syndrome and the Development of Alzheimer's Disease Neuropathology. Curr Alzheimer Res 2016; 13:18-29. [PMID: 26651341 PMCID: PMC4948181 DOI: 10.2174/1567205012666151020114607] [Citation(s) in RCA: 156] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 05/18/2015] [Accepted: 09/01/2015] [Indexed: 02/04/2023]
Abstract
Chromosome 21, triplicated in Down Syndrome, contains several genes that are thought to play a critical role in the development of AD neuropathology. The overexpression of the gene for the amyloid precursor protein (APP), on chromosome 21, leads to early onset beta-amyloid (Aβ) plaques in DS. In addition to Aβ accumulation, middle-aged people with DS develop neurofibrillary tangles, cerebrovascular pathology, white matter pathology, oxidative damage, neuroinflammation and neuron loss. There is also evidence of potential compensatory responses in DS that benefit the brain and delay the onset of dementia after there is sufficient neuropathology for a diagnosis of AD. This review describes some of the existing literature and also highlights gaps in our knowledge regarding AD neuropathology in DS. It will be critical in the future to develop networked brain banks with standardized collection procedures to fully characterize the regional and temporal pathological events associated with aging in DS. As more information is acquired regarding AD evolution in DS, there will be opportunities to develop interventions that are age-appropriate to delay AD in DS.
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Affiliation(s)
- Elizabeth Head
- Sanders Brown Center on Aging, University of Kentucky, 800 South Limestone Street, Lexington, KY, 40536, USA.
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13
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Donohue MC, Moghadam SH, Roe AD, Sun CK, Edland SD, Thomas RG, Petersen RC, Sano M, Galasko D, Aisen PS, Rissman RA. Longitudinal plasma amyloid beta in Alzheimer's disease clinical trials. Alzheimers Dement 2015; 11:1069-79. [PMID: 25301682 PMCID: PMC4387108 DOI: 10.1016/j.jalz.2014.07.156] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/13/2014] [Accepted: 07/05/2014] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Little is known about the utility of plasma amyloid beta (Aβ) in clinical trials of Alzheimer's disease (AD). METHODS We analyzed longitudinal plasma samples from two large multicenter clinical trials: (1) donezepil and vitamin E in mild cognitive impairment (n = 405, 24 months) and (2) simvastatin in mild to moderate AD (n = 225, 18 months). RESULTS Baseline plasma Aβ was not related to cognitive or clinical progression. We observed a decrease in plasma Aβ40 and 42 among apolipoprotein E epsilon 4 (APOE ε4) carriers relative to noncarriers in the mild cognitive impairment trial. Patients treated with simvastatin showed a significant increase in Aβ compared with placebo. We found significant storage time effects and considerable plate-to-plate variation. DISCUSSION We found no support for the utility of plasma Aβ as a prognostic factor or correlate of cognitive change. Analysis of stored specimens requires careful standardization and experimental design, but plasma Aβ may prove useful in pharmacodynamic studies of antiamyloid drugs.
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Affiliation(s)
- Michael C Donohue
- Alzheimer's Disease Cooperative Study, Department of Neurosciences, University of California San Diego, School of Medicine, San Diego, CA, USA; Department of Family Preventive Medicine, University of California San Diego, School of Medicine, San Diego, CA, USA
| | - Setareh H Moghadam
- Alzheimer's Disease Cooperative Study, Department of Neurosciences, University of California San Diego, School of Medicine, San Diego, CA, USA
| | - Allyson D Roe
- Alzheimer's Disease Cooperative Study, Department of Neurosciences, University of California San Diego, School of Medicine, San Diego, CA, USA
| | - Chung-Kai Sun
- Alzheimer's Disease Cooperative Study, Department of Neurosciences, University of California San Diego, School of Medicine, San Diego, CA, USA
| | - Steven D Edland
- Department of Family Preventive Medicine, University of California San Diego, School of Medicine, San Diego, CA, USA
| | - Ronald G Thomas
- Alzheimer's Disease Cooperative Study, Department of Neurosciences, University of California San Diego, School of Medicine, San Diego, CA, USA; Department of Family Preventive Medicine, University of California San Diego, School of Medicine, San Diego, CA, USA
| | - Ronald C Petersen
- Alzheimer's Disease Cooperative Study, Department of Neurosciences, University of California San Diego, School of Medicine, San Diego, CA, USA; Department of Neurology, Mayo Clinic Alzheimer's Disease Research Center, Department of Health Sciences Mayo Clinic College of Medicine, Research, Rochester, MN, USA
| | - Mary Sano
- Alzheimer's Disease Cooperative Study, Department of Neurosciences, University of California San Diego, School of Medicine, San Diego, CA, USA; Mount Sinai School of Medicine and James J. Peters Veterans Association Medical Center, Bronx, NY, USA
| | - Douglas Galasko
- Alzheimer's Disease Cooperative Study, Department of Neurosciences, University of California San Diego, School of Medicine, San Diego, CA, USA
| | - Paul S Aisen
- Alzheimer's Disease Cooperative Study, Department of Neurosciences, University of California San Diego, School of Medicine, San Diego, CA, USA
| | - Robert A Rissman
- Alzheimer's Disease Cooperative Study, Department of Neurosciences, University of California San Diego, School of Medicine, San Diego, CA, USA.
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Schupf N, Lee A, Park N, Dang LH, Pang D, Yale A, Oh DKT, Krinsky-McHale SJ, Jenkins EC, Luchsinger JA, Zigman WB, Silverman W, Tycko B, Kisselev S, Clark L, Lee JH. Candidate genes for Alzheimer's disease are associated with individual differences in plasma levels of beta amyloid peptides in adults with Down syndrome. Neurobiol Aging 2015; 36:2907.e1-10. [PMID: 26166206 DOI: 10.1016/j.neurobiolaging.2015.06.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 06/08/2015] [Accepted: 06/14/2015] [Indexed: 01/08/2023]
Abstract
We examined the contribution of candidates genes for Alzheimer's disease (AD) to individual differences in levels of beta amyloid peptides in adults with Down syndrom, a population at high risk for AD. Participants were 254 non-demented adults with Down syndrome, 30-78 years of age. Genomic deoxyribonucleic acid was genotyped using an Illumina GoldenGate custom array. We used linear regression to examine differences in levels of Aβ peptides associated with the number of risk alleles, adjusting for age, sex, level of intellectual disability, race and/or ethnicity, and the presence of the APOE ε4 allele. For Aβ42 levels, the strongest gene-wise association was found for a single nucleotide polymorphism (SNP) on CAHLM1; for Aβ40 levels, the strongest gene-wise associations were found for SNPs in IDE and SOD1, while the strongest gene-wise associations with levels of the Aβ42/Aβ40 ratio were found for SNPs in SORCS1. Broadly classified, variants in these genes may influence amyloid precursor protein processing (CALHM1, IDE), vesicular trafficking (SORCS1), and response to oxidative stress (SOD1).
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Affiliation(s)
- Nicole Schupf
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA; G.H. Sergievsky Center, New York, NY, USA; Department of Epidemiology, Columbia University Medical Center, New York, NY, USA; Department of Psychiatry, Columbia University Medical Center, New York, NY, USA.
| | - Annie Lee
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA
| | - Naeun Park
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA
| | - Lam-Ha Dang
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA
| | - Deborah Pang
- Department of Psychology, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - Alexander Yale
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - David Kyung-Taek Oh
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Sharon J Krinsky-McHale
- Department of Psychology, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - Edmund C Jenkins
- Department of Human Genetics, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - José A Luchsinger
- Department of Medicine, Columbia University Medical Center, New York, NY, USA
| | - Warren B Zigman
- Department of Psychology, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - Wayne Silverman
- Kennedy Krieger Institute and Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Benjamin Tycko
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Sergey Kisselev
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA
| | - Lorraine Clark
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA
| | - Joseph H Lee
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA; G.H. Sergievsky Center, New York, NY, USA; Department of Epidemiology, Columbia University Medical Center, New York, NY, USA
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15
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Evans E, Bhardwaj A, Brodaty H, Sachdev P, Draper B, Trollor JN. Dementia in people with intellectual disability: insights and challenges in epidemiological research with an at-risk population. Int Rev Psychiatry 2013; 25:755-63. [PMID: 24423228 DOI: 10.3109/09540261.2013.866938] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The population with intellectual disability (ID) is ageing, but age-related health concerns such as dementia have received little research attention thus far. We review evidence regarding the prevalence and incidence of dementia in people with ID, and discuss some possible explanations for an increased risk, such as shared genetic risk factors, co-morbid physical and mental disorders, lifestyle factors, trauma, and lowered brain reserve. We discuss practical and theoretical challenges facing researchers in this field, before highlighting the implications of findings to date for future research and clinical care. Research on dementia in this at-risk population has the potential to help us understand dementia in general and to improve services for this group of vulnerable individuals.
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Affiliation(s)
- Elizabeth Evans
- Department of Developmental Disability Neuropsychiatry, School of Psychiatry, University of New South Wales , Sydney, NSW
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16
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Obeid R, Hartmuth K, Herrmann W, Gortner L, Rohrer TR, Geisel J, Reed MC, Nijhout HF. Blood biomarkers of methylation in Down syndrome and metabolic simulations using a mathematical model. Mol Nutr Food Res 2012; 56:1582-9. [PMID: 22930479 DOI: 10.1002/mnfr.201200162] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 06/22/2012] [Accepted: 07/05/2012] [Indexed: 12/29/2022]
Abstract
SCOPE The study tests the metabolites of the methylation cycle in individuals with Down syndrome (DS) and applies a mathematical model in order to change this cycle by nutritional factors. METHODS AND RESULTS We measured concentrations of the metabolites related to the methylation cycle in the blood of 35 young individuals with DS and 47 controls of comparable age. Moreover, we applied a mathematical model to learn more about the regulation of the methylation cycle in DS. Concentrations of cystathionine, cysteine, betaine, choline, dimethylglycine, S-adenosylhomocysteine (SAH), S-adenosylmethionine (SAM), and holotranscobalamin were significantly higher in DS compared to the controls. The median SAM/SAH ratio was lower in DS and that of methionine and reduced glutathione did not differ significantly between the groups. The mathematical model showed that enhanced methionine turnover and accelerated Hcy-remethylation might explain the shift in the methylation cycle in DS. CONCLUSION In addition to the DS-related excess of cystathionine beta synthase (CBS) activity, increases in the activities of MS and betaine homocysteine methyl transferase, and in methionine input were necessary to account for the changes in metabolite levels observed in DS. A low-methionine diet might offer a perspective for reversing the metabolic imbalance in DS, but this awaits clinical investigations.
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Affiliation(s)
- Rima Obeid
- Department of Clinical Chemistry and Laboratory Medicine, Saarland University, Medical Centre, Homburg, Germany.
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17
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Sterol lipid metabolism in down syndrome revisited: down syndrome is associated with a selective reduction in serum brassicasterol levels. Curr Gerontol Geriatr Res 2012; 2012:179318. [PMID: 22649448 PMCID: PMC3357506 DOI: 10.1155/2012/179318] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Accepted: 02/22/2012] [Indexed: 02/03/2023] Open
Abstract
Over the past 15 years, insights into sterol metabolism have improved our understanding of the relationship between lipids and common conditions such as atherosclerosis and Alzheimer's Disease (AD). A better understanding of sterol lipid metabolism in individuals with Down Syndrome (DS) may help elucidate how this population's unique metabolic characteristics influence their risks for atherosclerosis and AD. To revisit the question of whether sterol lipid parameters may be altered in DS subjects, we performed a pilot study to assess traditional serum sterol lipids and lipoproteins, as well as markers of sterol biosynthesis, metabolites, and plant sterols in 20 subjects with DS compared to age-matched controls. Here we report that the levels of nearly all lipids and lipoproteins examined are similar to control subjects, suggesting that trisomy 21 does not lead to pronounced general alterations in sterol lipid metabolism. However, the levels of serum brassicasterol were markedly reduced in DS subjects.
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18
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Head E, Doran E, Nistor M, Hill M, Schmitt FA, Haier RJ, Lott IT. Plasma amyloid-β as a function of age, level of intellectual disability, and presence of dementia in Down syndrome. J Alzheimers Dis 2011; 23:399-409. [PMID: 21116050 DOI: 10.3233/jad-2010-101335] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Adults with Down syndrome (DS) are at risk for developing Alzheimer's disease (AD). While plasma amyloid-β (Aβ) is known to be elevated in DS, its relationship to cognitive functioning is unknown. To assess this relationship, samples from two groups of subjects were used. In the first group, nondemented adults with DS were compared to: 1) a group of young and old individuals without DS and 2) to a group of patients with AD. Compared to these controls, there were significantly higher levels of plasma Aβ in nondemented adults with DS while AD patients showed lower levels of plasma Aβ. A larger second group included demented and nondemented adults with DS, in order to test the hypothesis that plasma Aβ may vary as a function of dementia and Apolipoprotein E (ApoE) genotype. Plasma Aβ levels alone did not dissociate DS adults with and without dementia. However, in demented adults with DS, ApoE4 was associated with higher Aβ40 but not Aβ42. After controlling for level of intellectual disability (mild, moderate, severe) and the presence or absence of dementia, there was an improved prediction of neuropsychological scores by plasma Aβ. In summary, plasma Aβ can help predict cognitive function in adults with DS independently of the presence or absence of dementia.
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Affiliation(s)
- Elizabeth Head
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA 40536, USA.
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19
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Mohamad López H. Transfer of the amyloid β and/or of β-amyloid precursor protein of the fetus with trisomy 21 to the maternal blood stream and its possible contribution to the pathogenesis of the maternal Alzheimer's Disease. Med Hypotheses 2011; 77:1058-61. [PMID: 21944886 DOI: 10.1016/j.mehy.2011.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 08/08/2011] [Accepted: 09/02/2011] [Indexed: 10/17/2022]
Abstract
Down Syndrome (DS) is the most frequent genetic pathology. It affects 1 out of every 800 newborn babies. Approximately between a 90% and a 95% of all the cases of DS are attributed to a trisomy in chromosome 21. One of the genes contained in this chromosome is the gene of β-amyloid precursor protein (βAPP). The metabolism of this protein yields, among others, the amyloid beta peptides made up of 40 amino acids (Aβ40) and 42 amino acids (Aβ42). The evidence that is derived from several sources--genetic, among them--suggests that the Aβ participates in the pathogenesis of Alzheimer's Disease (AD). It is worth pointing at the fact that the transfer of cells, extracellular chromosomal material and some proteins from the fetus to the mother and vice versa has been widely described. The transfer rate from the fetus to the mother is higher when the mother is carrying a baby with trisomy 21. This has led to the hypothesis that sets forth that during the gestation of a baby with DS there is a greater fetomaternal transfer of cells and of products of the genes of chromosome 21--among them, βAPP and its metabolites Aβ40 and Aβ42. It is possible to speculate on the possible contribution of the fetal components--among them, Aβ--to the higher risk of suffering AD, which has been reported in a subpopulation of women who have given birth to children with DS. On the other hand, the detection of the βAPP--mainly intracellular--and of the β amyloid peptides in maternal blood and urine during the early stages of gestation could be taken as a potential non invasive biochemical prenatal marker of DS.
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Affiliation(s)
- Himara Mohamad López
- Cátedra de Bioquímica, Escuela de Medicina Luis Razzetti, Facultad de Medicina, Universidad Central de Venezuela, Luis Razzetti School of Medicine, Faculty of Medicine, Central University of Venezuela, Caracas, Venezuela.
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20
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Fei M, Jianghua W, Rujuan M, Wei Z, Qian W. The relationship of plasma Aβ levels to dementia in aging individuals with mild cognitive impairment. J Neurol Sci 2011; 305:92-6. [DOI: 10.1016/j.jns.2011.03.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Accepted: 03/01/2011] [Indexed: 11/28/2022]
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21
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Schupf N, Zigman WB, Tang MX, Pang D, Mayeux R, Mehta P, Silverman W. Change in plasma Aß peptides and onset of dementia in adults with Down syndrome. Neurology 2010; 75:1639-44. [PMID: 21041786 DOI: 10.1212/wnl.0b013e3181fb448b] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To examine changes in levels of plasma amyloid-β (Aβ) peptides, Aβ42 and Aβ40, in relation to onset of Alzheimer disease (AD) in adults with Down syndrome (DS). METHODS Plasma Aβ42 and Aβ40 were measured at initial examination and at follow-up in a community-based cohort of 225 adults with DS who did not have dementia at baseline and were assessed for cognitive/functional abilities and health status and followed at 14- to 20-month intervals. We used Cox proportional hazards modeling to estimate the cumulative incidence of AD by Aβ peptide change group (increasing, no change, or decreasing), adjusting for covariates. RESULTS Sixty-one (27.1%) of the participants developed AD. At follow-up, a decrease in Aβ42 levels, a decrease in the Aβ42/Aβ40 ratio, and an increase in Aβ40 levels were related to conversion to AD. Compared with the group with increasing levels of Aβ42, the likelihood of developing AD was 5 times higher for those whose plasma Aβ42 levels decreased over follow-up (hazard ratio [HR] = 4.9, 95% confidence interval [CI] 2.1-11.4). Decreasing Aβ42/Aβ40 was also strongly related to AD risk (HR = 4.9, 95% CI 1.8-13.2), while decreasing Aβ40 was associated with lower risk (HR = 0.4, 95% CI 0.2-0.9). CONCLUSIONS Among adults with DS, decreasing levels of plasma Aβ42, a decline in the Aβ42/Aβ40 ratio, or increasing levels of Aβ40 may be sensitive indicators of conversion to AD, possibly reflecting compartmentalization of Aβ peptides in the brain.
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Affiliation(s)
- N Schupf
- Taub Institute for Research on AD and the Aging Brain, Columbia University Medical Center, 630 West 168th Street, New York, NY 10032, USA.
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22
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Dafnis I, Stratikos E, Tzinia A, Tsilibary EC, Zannis VI, Chroni A. An apolipoprotein E4 fragment can promote intracellular accumulation of amyloid peptide beta 42. J Neurochem 2010; 115:873-84. [PMID: 20412390 DOI: 10.1111/j.1471-4159.2010.06756.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Apolipoprotein E (apoE) plays a crucial role in lipid transport in circulation and the brain. The apoE4 isoform is a major risk factor for Alzheimer's disease (AD). ApoE4 is more susceptible to proteolysis than other apoE isoforms and apoE4 fragments have been found in brains of AD patients. These apoE4 fragments have been hypothesized to be involved in the pathogenesis of AD, although the mechanism is not clear. In this study we examined the effect of lipid-free apoE4 on amyloid precursor protein processing and 40-amino-acid Aβ variant and 42-amino-acid Aβ variant levels in human neuroblastoma SK-N-SH cells. We discovered that a specific apoE4 fragment, apoE4[Δ(166-299)], can promote the cellular uptake of extracellular 40-amino-acid Aβ variant and 42-amino-acid Aβ variant either generated after amyloid precursor protein transfection or added exogenously. A longer length fragment, apoE4[Δ(186-299)], or full-length apoE4 failed to elicit this effect. ApoE4[Δ(166-299)] effected a 20% reduction of cellular sphingomyelin levels, as well as changes in cellular membrane micro-fluidity. Following uptake, approximately 50% of 42-amino-acid Aβ variant remained within the cell for at least 24 h, and led to increased formation of reactive oxygen species. Overall, our findings suggest a direct link between two early events in the pathogenesis of AD, apoE4 proteolysis and intraneuronal presence of amyloid beta peptide.
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Affiliation(s)
- Ioannis Dafnis
- Institute of Biology, National Center for Scientific Research Demokritos, Athens, Greece
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23
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Barron AM, Verdile G, Taddei K, Bates KA, Martins RN. Effect of chronic hCG administration on Alzheimer's-related cognition and A beta accumulation in PS1KI mice. Endocrinology 2010; 151:5380-8. [PMID: 20844010 DOI: 10.1210/en.2009-1168] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Age-associated changes in the reproductive hormones-the gonadal steroid hormones and the gonadotropins-have been identified as potential risk factors for Alzheimer's disease (AD). However, levels of gonadotropins and estrogens are closely linked in vivo, and it has proven difficult to separate the effects of gonadotropins from the well-documented estrogenic effects on AD-related neuropathology in experimental models of menopause. To assess the effects of gonadotropins on cognition and AD biochemical markers independent of estrogenic effects, a potent analog of luteinizing hormone [human chorionic gonadotropin (hCG)] was administered to ovariectomized presenilin1 knock-in mice (PS1KI). Gonadotropin administration was found to induce hyperactivity and anxiety (Open Field Maze and Taste Neophobia Task) and working memory dysfunction, without altering reference memory (Morris Water Maze). Although gonadotropin administration modestly altered β amyloid (Aβ40) levels, levels of the longer more toxic form (Aβ42) were unaffected. Furthermore, altered Aβ40 levels were not associated with observed behavioral and cognitive impairments. These findings provide proof, in principle, that the gonadotropin hormones play a role in the modulation of AD-related behavior, cognition, and neuropathology.
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Affiliation(s)
- A M Barron
- School of Psychiatry and Clinical Neurosciences, The University of Western Australia, Nedlands, 6009, Australia
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The relationship of plasma Abeta levels to dementia in aging individuals with Down syndrome. Alzheimer Dis Assoc Disord 2010; 23:315-8. [PMID: 19571732 DOI: 10.1097/wad.0b013e3181aba61e] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
To study the relationship between plasma levels of amyloid beta (Abeta) peptides and dementia in aging individuals with Down syndrome, we investigated the relationship among plasma Abeta, apolipoprotein E genotype and cognitive and clinical factors using baseline specimens form participants in an ongoing clinical trial in individuals with Down syndrome 50 years of age and older. Because of substantial skew in the distribution of peptide levels, analyses used log transformations of the data. The ratio of Abeta42 to Abeta40 was associated with the presence of dementia (P=0.003, df=196, F=9.37); this association persisted after adjustment for age, sex level of mental retardation, and apolipoprotein E genotype. Consistent with recent reports regarding the effect of presenilin mutations on peptide generation, our finding supports the theory that the ratio of Abeta42 to Abeta40 rather than absolute levels of the peptides is important to the pathophysiology of Alzheimer's disease in genetically susceptible populations.
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Prasher VP, Sajith SG, Mehta P, Zigman WB, Schupf N. Plasma beta-amyloid and duration of Alzheimer's disease in adults with Down syndrome. Int J Geriatr Psychiatry 2010; 25:202-7. [PMID: 19513990 PMCID: PMC2811215 DOI: 10.1002/gps.2321] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVES To investigate the relation of plasma levels of Abeta peptides (Abeta1-40 and Abeta1-42) and apolipoprotein E (APOE) genotype to dementia status, and the duration of Alzheimer's disease (AD) in adults with Down syndrome (DS). METHODS Adults with DS were recruited from community settings and followed up for a mean period of 6.7 years. Plasma levels Abeta1-40 and Abeta1-42 and APOE genotype were determined at the last visit. RESULTS There were 83 nondemented participants and 44 participants with prevalent AD. Overall, plasma levels of Abeta1-42, Abeta1-40 and the ratio Abeta1-42/Abeta1-40 did not differ significantly between the adults with DS. Among demented participants, the mean level of Abeta1-40 was significantly lower (157.0 vs. 195.3) and the ratio of Abeta1-42/Abeta1-40 was significantly higher (0.28 vs. 0.16) in those with more than 4 years duration of dementia than in those with 4 or fewer years' duration of dementia. This pattern was generally similar in those with and without an APOE epsilon4 allele. CONCLUSIONS There is an association between plasma Abeta peptide levels and the duration of AD in older persons with DS. The predictive and diagnostic roles of Abeta1-42 and Abeta1-40 measurements for AD, however, remain controversial. Change in Abeta peptide levels with onset of AD and with the duration of dementia may account for a lack of difference between prevalent cases and nondemented individuals and for variation in the predictive power of Abeta peptide levels.
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Affiliation(s)
- V P Prasher
- Monyhull Hospital, Liverpool John Moore University, c/o The Greenfields, Monyhull, Birmingham, UK.
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Barron AM, Cake M, Verdile G, Martins RN. Ovariectomy and 17beta-estradiol replacement do not alter beta-amyloid levels in sheep brain. Endocrinology 2009; 150:3228-36. [PMID: 19282379 PMCID: PMC2703524 DOI: 10.1210/en.2008-1252] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Accepted: 03/03/2009] [Indexed: 11/19/2022]
Abstract
The benefits of estrogen replacement as a preventative treatment for Alzheimer's disease (AD) are subject to debate. Because the effects of estrogen depletion and replacement on accumulation of the neurotoxic beta-amyloid (A beta) peptide in transgenic animal models of AD have been variable, we examined A beta levels and oxidative stress in a nontransgenic animal model. Sheep have traditionally been used as a model for human reproduction; however because they share 100% sequence homology with the human form of A beta, they may also have potential as a nontransgenic model for A beta biology. The effect of ovariectomy and estrogen replacement administered for 6 months via slow-release implant was examined in the brain of 4.5-yr-old sheep. A beta levels were measured by ELISA, and protein levels of the amyloid precursor protein (APP), APP C-terminal fragments (C100), and presenilin-1 were examined semiquantitatively by Western blot as markers of APP processing. Markers of oxidative stress were examined semiquantitatively by Western blot [4-hydroxy-2(E)-nonenal] and oxyblot (protein carbonyls). We found no effects of estrogen depletion and supplementation in terms of AD-related biochemical markers, including A beta levels, APP processing, and oxidative stress levels. Evidence of a trend toward increased P450 side-chain cleavage enzyme levels in the hippocampus of ovariectomized and estrogen supplemented sheep suggests that neurosteroidogenesis may compensate for gonadal estrogen depletion; however, these findings cannot explain the lack of effect of estrogen supplementation on APP processing. It is possible that supraphysiological doses of estrogen are necessary to yield antiamyloidogenic and antioxidative benefits in ovariectomized sheep.
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Affiliation(s)
- A M Barron
- School of Psychiatry and Clinical Neurosciences, The University of Western Australia, Nedlands, Australia
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Amyloid beta concentrations in older people with Down syndrome and dementia. Neurosci Lett 2008; 451:162-4. [PMID: 19111900 DOI: 10.1016/j.neulet.2008.12.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 12/16/2008] [Accepted: 12/17/2008] [Indexed: 11/28/2022]
Abstract
People with Down syndrome develop Alzheimer's disease with an early age of onset. Plasma amyloid beta (Abeta) levels were measured in individuals with Down syndrome who were over the age of 40. No associations between age and Abeta1-40 and Abeta1-42 concentrations were found and nor were Abeta1-40 and Abeta1-42 levels found to vary between those with Alzheimer's-type dementia and those without dementia. The APOE genotype was not found to have an impact upon Abeta1-40 or Abeta1-42 concentrations. These data suggest that other factors play important roles in determining the onset and progression of dementia in the Down syndrome population.
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Synergistic effect of apolipoprotein E epsilon4 and butyrylcholinesterase K-variant on progression from mild cognitive impairment to Alzheimer's disease. Pharmacogenet Genomics 2008; 18:289-98. [PMID: 18334913 DOI: 10.1097/fpc.0b013e3282f63f29] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To evaluate the synergistic effects of the apolipoprotein E (APOE) epsilon4 and butyrylcholinesterase K-variant (BCHE-K) alleles on progression to Alzheimer's disease (AD) in individuals with mild cognitive impairment (MCI). METHODS This was a post-hoc exploratory analysis from a 3-4-year, randomized, placebo-controlled study of rivastigmine in participants with MCI (InDDEx study). Participants who consented to genetic testing were included in the current analyses. The incidence of progression to AD, cognitive decline and changes in MRI brain volumes were investigated in participants from the placebo arm of the InDDEx study. RESULTS Of the 1018 participants in the overall study, 464 were successfully genotyped for both APOE and butyrylcholinesterase. Of these, 68 (14.7%) carried > or =1 APOE epsilon4 and > or =1 BCHE-K allele. The presence of APOE epsilon4 was associated with a significantly higher incidence of progression to AD whereas the presence of BCHE-K had no independent effect on progression. A synergistic effect of the combined presence of APOE epsilon4 and BCHE-K on the time to clinical diagnosis of AD and on MRI brain volumes was seen. Progression to AD and hippocampal volumetric loss was greatest in participants who carried both APOE epsilon4 and BCHE-K alleles and lowest in BCHE-K carriers without the APOE epsilon4 allele. CONCLUSION In MCI, the risk of cognitive decline, hippocampal volumetric loss and progression to AD seems to be the greatest in individuals who carry at least one copy of both the BCHE-K and APOE epsilon4 alleles.
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Lanz TA, Schachter JB. Solid-phase extraction enhances detection of beta-amyloid peptides in plasma and enables Abeta quantification following passive immunization with Abeta antibodies. J Neurosci Methods 2007; 169:16-22. [PMID: 18160105 DOI: 10.1016/j.jneumeth.2007.11.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Revised: 11/16/2007] [Accepted: 11/17/2007] [Indexed: 12/01/2022]
Abstract
We have previously developed a solid-phase extraction (SPE) procedure to enable the detection of beta-amyloid (Abeta) peptides in brain tissue from non-transgenic animals. We have now adapted these methods to enrich the Abeta fraction in cerebrospinal fluid (CSF) and plasma. Human CSF and plasma and Tg2576 mouse plasma were subjected to guanidine denaturation followed by SPE in 96-well cassettes. The resulting eluates could be concentrated significantly to enhance detection of low-abundance Abeta peptides by immunoassay. The concentrated eluates diluted in a linear fashion with consistent recovery between SPE columns. This technique was therefore used to facilitate quantification of Abeta1-X, 1-40, 1-42, and 1-38 peptides in normal human CSF and plasma samples. SPE sample preparation was also applied to the plasma of mice dosed peripherally with a monoclonal antibody raised against Abeta. When such samples were assayed directly, the presence of the systemically administered antibody interfered with the subsequent immunoassay, by preventing detection of antibody-bound Abeta. After subjecting plasma from antibody-treated animals to denaturation and SPE, the antibody-antigen complex was disrupted, and the Abeta fraction could be isolated from the antibody-containing fraction. Application of this method allowed for detection of a 100-fold increase in plasma Abeta1-40 following treatment of Tg2576 mice or wild type littermate control mice with Abeta40-specific monoclonal antibody 9TL. Given the availability of a variety of SPE matrices, we hypothesize that these methods could facilitate plasma antigen retrieval using multiple therapeutic antibody approaches.
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Affiliation(s)
- Thomas A Lanz
- CNS Biology, Pfizer Inc., Groton, CT 06340, United States.
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Schupf N, Patel B, Pang D, Zigman WB, Silverman W, Mehta PD, Mayeux R. Elevated plasma beta-amyloid peptide Abeta(42) levels, incident dementia, and mortality in Down syndrome. ACTA ACUST UNITED AC 2007; 64:1007-13. [PMID: 17620492 PMCID: PMC2587094 DOI: 10.1001/archneur.64.7.1007] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND Deposition of the beta-amyloid peptide Abeta(42) is thought to be an important initial step in the pathogenesis of Alzheimer disease (AD). Individuals with Down syndrome have increased levels of beta-amyloid peptides and an increased risk for AD. OBJECTIVE To examine the relation of plasma levels of Abeta(42) and Abeta(40) to the risk of dementia in nondemented participants and all-cause mortality in adults with Down syndrome. DESIGN Prospective, community-based longitudinal cohort study. SETTING State and voluntary service providers in New York State. PARTICIPANTS Adults with Down syndrome (N = 204). MAIN OUTCOME MEASURE Plasma Abeta(42) and Abeta(40) levels were measured at initial examination. Participants were assessed for cognitive and functional abilities, behavioral/psychiatric conditions, and health and vital status at 14- to 18-month intervals for 4 cycles of data collection. RESULTS Among participants who were nondemented at baseline, those in the middle and highest tertiles of plasma Abeta(42) levels were more than 2 times as likely to develop AD as those in the lowest tertile. Compared with participants without AD, participants with prevalent AD had higher levels of plasma Abeta(42) but not Abeta(40). Among all participants, those in the highest tertile of plasma Abeta(42) level at baseline were more than twice as likely to die during the study period as those in the lowest tertile, whereas there was no difference in risk of death between those in the middle and lowest tertiles of plasma Abeta(42) level. CONCLUSION Elevations in plasma Abeta(42) peptide levels are associated with earlier onset of AD and increased risk of death.
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Affiliation(s)
- Nicole Schupf
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, PO Box 16, 630 W 168th St, New York, NY 10032, USA.
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Mehta PD, Capone G, Jewell A, Freedland RL. Increased amyloid beta protein levels in children and adolescents with Down syndrome. J Neurol Sci 2007; 254:22-7. [PMID: 17275850 DOI: 10.1016/j.jns.2006.12.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Revised: 12/01/2006] [Accepted: 12/04/2006] [Indexed: 11/29/2022]
Abstract
BACKGROUND Persons with Down syndrome (DS) (40 years and older) have neuropathological changes characteristic of Alzheimer disease (AD). Soluble forms of amyloid beta (Abeta) peptide generated from amyloid precursor protein (APP) end at C-terminal residues 40 and 42. The presence of the apolipoprotein E (ApoE) epsilon4 allele is a significant risk factor for the development of sporadic AD. Although preliminary studies have shown an association of plasma Abeta42 and ApoE epsilon4 allele in older persons with DS who have dementia, the relationship between plasma Abeta40 and Abeta42 levels and ApoE phenotypes in children with DS has not been examined. Inflammation might play a role in the growth of DS brains. Neopterin is an immune activation marker for the cell-mediated immune response. OBJECTIVE To examine the levels of plasma Abeta40, Abeta42, and neopterin in children or adolescents with DS or controls. MATERIALS AND METHODS Blood was collected from DS (N=35; 7+/-3.8 years old) and their siblings (N=34; 10+/-4.5). Plasma Abeta40 and Abeta42, and neopterin levels were quantitated by sandwich ELISA. RESULTS Abeta40 and Abeta42 levels were higher in DS than controls. The ratio of Abeta42/Abeta40 was lower in DS than in controls. There were significant negative correlations between age and Abeta40 in DS and controls, and between age and Abeta42 levels in DS but not in controls. There was no association of Abeta40 or Abeta42 levels with Apo E in either group. Neopterin levels were higher in DS than controls, and the levels were not correlated with Abeta40 and Abeta42 levels in DS or controls. CONCLUSIONS The over expression of APP gene in DS leads to increases in plasma Abeta40 and Abeta42 levels before plaque formation in DS brain. Higher neopterin concentrations in DS reflect inflammatory cell activation. Further studies are needed to determine whether DS children with lower plasma Abeta42/Abeta40 ratios are at increased risk of developing AD during aging than those with higher ratios.
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Affiliation(s)
- Pankaj D Mehta
- Department of Developmental Neurobiology, Department of Infant Development, New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314-6399, United States.
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Gorgas K, Teigler A, Komljenovic D, Just WW. The ether lipid-deficient mouse: Tracking down plasmalogen functions. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:1511-26. [PMID: 17027098 DOI: 10.1016/j.bbamcr.2006.08.038] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Revised: 08/15/2006] [Accepted: 08/23/2006] [Indexed: 10/24/2022]
Abstract
Chemical and physico-chemical properties as well as physiological functions of major mammalian ether-linked glycerolipids, including plasmalogens were reviewed. Their chemical structures were described and their effect on membrane fluidity and membrane fusion discussed. The recent generation of mouse models with ether lipid deficiency offered the possibility to study ether lipid and particularly plasmalogen functions in vivo. Ether lipid-deficient mice revealed severe phenotypic alterations, including arrest of spermatogenesis, development of cataract and defects in central nervous system myelination. In several cell culture systems lack of plasmalogens impaired intracellular cholesterol distribution affecting plasma membrane functions and structural changes of ER and Golgi cisternae. Based on these phenotypic anomalies that were accurately described conclusions were drawn on putative functions of plasmalogens. These functions were related to cell-cell or cell-extracellular matrix interactions, formation of lipid raft microdomains and intracellular cholesterol homeostasis. There are several human disorders, such as Zellweger syndrome, rhizomelic chondrodysplasia punctata, Alzheimer's disease, Down syndrome, and Niemann-Pick type C disease that are distinguished by altered tissue plasmalogen concentrations. The role plasmalogens might play in the pathology of these disorders is discussed.
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Affiliation(s)
- Karin Gorgas
- Institut für Anatomie und Zellbiologie, Abteilung Medizinische Zellbiologie, Im Neuenheimer Feld 307, D-69120 Heidelberg, Germany
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Lanz TA, Schachter JB. Demonstration of a common artifact in immunosorbent assays of brain extracts: Development of a solid-phase extraction protocol to enable measurement of amyloid-β from wild-type rodent brain. J Neurosci Methods 2006; 157:71-81. [PMID: 16678274 DOI: 10.1016/j.jneumeth.2006.03.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Revised: 03/30/2006] [Accepted: 03/31/2006] [Indexed: 11/23/2022]
Abstract
In the process of developing species-specific, immunosorbent assays for brain amyloid-beta (Abeta) in non-transgenic animals, we have demonstrated an artifact that impedes accurate quantitation of Abeta in this assay format. Using synthetic peptides, cerebrospinal fluid (CSF), or plasma samples, no nonspecific binding or cross-species immunoreactivity was detected in human or rodent Abeta assays. However, extracts of guinea pig brain (human Abeta sequence) or rat brain (rodent Abeta sequence) demonstrated immunoreactivity regardless of which capture antibody, detection antibody, or reporter method (colorimetric or fluorescent) was used. This immunoreactivity remained even in the absence of a capture antibody. Various blocking conditions failed to resolve the nonspecific binding of detection antibodies in the presence of brain extracts. Fractionation of DEA-extracted guinea pig brain over Sephadex G-50 demonstrated the feasibility of separating specific from nonspecific binding components in the brain extracts. Thus, a solid phase extraction method, compatible with multiple extraction buffers, has been developed to isolate and concentrate Abeta from brain extracts. This isolation method eliminates non-specific binding components from brain extracts and allows for accurate quantitation and robust detection of multiple Abeta peptides in extracts from wild-type animals.
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Affiliation(s)
- Thomas A Lanz
- CNS Biology, Pfizer Inc., MS# 8220-4183, Eastern Point Road, Groton, CT 06340, USA.
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Lanz TA, Karmilowicz MJ, Wood KM, Pozdnyakov N, Du P, Piotrowski MA, Brown TM, Nolan CE, Richter KEG, Finley JE, Fei Q, Ebbinghaus CF, Chen YL, Spracklin DK, Tate B, Geoghegan KF, Lau LF, Auperin DD, Schachter JB. Concentration-dependent modulation of amyloid-beta in vivo and in vitro using the gamma-secretase inhibitor, LY-450139. J Pharmacol Exp Ther 2006; 319:924-33. [PMID: 16920992 DOI: 10.1124/jpet.106.110700] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
LY-450139 is a gamma-secretase inhibitor shown to have efficacy in multiple cellular and animal models. Paradoxically, robust elevations of plasma amyloid-beta (Abeta) have been reported in dogs and humans after administration of subefficacious doses. The present study sought to further evaluate Abeta responses to LY-450139 in the guinea pig, a nontransgenic model that has an Abeta sequence identical to that of human. Male guinea pigs were treated with LY-450139 (0.2-60 mg/kg), and brain, cerebrospinal fluid, and plasma Abeta levels were characterized at 1, 3, 6, 9, and 14 h postdose. Low doses significantly elevated plasma Abeta levels at early time points, with return to baseline within hours. Higher doses inhibited Abeta levels in all compartments at early time points, but elevated plasma Abeta levels at later time points. To determine whether this phenomenon occurs under steady-state drug exposure, guinea pigs were implanted with subcutaneous minipumps delivering LY-450139 (0.3-30 mg/kg/day) for 5 days. Plasma Abeta was significantly inhibited at 10-30 mg/kg/day, but significantly elevated at 1 mg/kg/day. To further understand the mechanism of Abeta elevation by LY-450139, H4 cells overexpressing the Swedish mutant of amyloid-precursor protein and a mouse embryonic stem cell-derived neuronal cell line were studied. In both cellular models, elevated levels of secreted Abeta were observed at subefficacious concentrations, whereas dose-responsive inhibition was observed at higher concentrations. These results suggest that LY-450139 modulates the gamma-secretase complex, eliciting Abeta lowering at high concentrations but Abeta elevation at low concentrations.
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Affiliation(s)
- Thomas A Lanz
- Pfizer, Inc., Eastern Point Rd., MS# 8220-4183, Groton, CT 06340, USA.
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Nistor M, Don M, Parekh M, Sarsoza F, Goodus M, Lopez G, Kawas C, Leverenz J, Doran E, Lott I, Hill M, Head E. Alpha- and beta-secretase activity as a function of age and beta-amyloid in Down syndrome and normal brain. Neurobiol Aging 2006; 28:1493-506. [PMID: 16904243 PMCID: PMC3375834 DOI: 10.1016/j.neurobiolaging.2006.06.023] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2005] [Revised: 05/09/2006] [Accepted: 06/21/2006] [Indexed: 11/22/2022]
Abstract
Aged individuals with Down syndrome (DS) develop Alzheimer's disease (AD) neuropathology by the age of 40 years. The purpose of the current study was to measure age-associated changes in APP processing in 36 individuals with DS (5 months-69 years) and in 26 controls (5 months-100 years). Alpha-secretase significantly decreased with age in DS, particularly in cases over the age of 40 years and was stable in controls. The levels of C-terminal fragments of APP reflecting alpha-secretase processing (CTF-alpha) decreased with age in both groups. In both groups, there was significant increase in beta-secretase activity with age. CTF-beta remained constant with age in controls suggesting compensatory increases in turnover/clearance mechanisms. In DS, young individuals had the lowest CTF-beta levels that may reflect rapid conversion of beta-amyloid (Abeta) to soluble pools or efficient CTF-beta clearance mechanisms. Treatments to slow or prevent AD in the general population targeting secretase activity may be more efficacious in adults with DS if combined with approaches that enhance Abeta degradation and clearance.
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Affiliation(s)
- M. Nistor
- Institute for Brain Aging & Dementia, CA, United States
| | - M. Don
- Institute for Brain Aging & Dementia, CA, United States
| | - M. Parekh
- Institute for Brain Aging & Dementia, CA, United States
| | - F. Sarsoza
- Institute for Brain Aging & Dementia, CA, United States
| | - M. Goodus
- Institute for Brain Aging & Dementia, CA, United States
- Department of Neurology, University of California, 1259 Gillespie NRF, Irvine, CA 92697-4540, United States
| | - G.E. Lopez
- Institute for Brain Aging & Dementia, CA, United States
- Department of Neurology, University of California, 1259 Gillespie NRF, Irvine, CA 92697-4540, United States
| | - C. Kawas
- Institute for Brain Aging & Dementia, CA, United States
- Department of Neurology, University of California, 1259 Gillespie NRF, Irvine, CA 92697-4540, United States
| | - J. Leverenz
- Neurology and Psychiatry and Behavioral Sciences, University of Washington Seattle, WA 98108, United States
| | - E. Doran
- Institute for Brain Aging & Dementia, CA, United States
| | - I.T. Lott
- Institute for Brain Aging & Dementia, CA, United States
- Department of Neurology, University of California, 1259 Gillespie NRF, Irvine, CA 92697-4540, United States
| | - M. Hill
- Institute for Brain Aging & Dementia, CA, United States
- Department of Neurology, University of California, 1259 Gillespie NRF, Irvine, CA 92697-4540, United States
| | - E. Head
- Institute for Brain Aging & Dementia, CA, United States
- Department of Neurology, University of California, 1259 Gillespie NRF, Irvine, CA 92697-4540, United States
- Corresponding author. Tel.: +1 949 824 8700; fax: +1 949 824 2071. (E. Head)
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Pomara N, Doraiswamy PM, Willoughby LM, Roth AE, Mulsant BH, Sidtis JJ, Mehta PD, Reynolds CF, Pollock BG. Elevation in plasma Abeta42 in geriatric depression: a pilot study. Neurochem Res 2006; 31:341-9. [PMID: 16583267 DOI: 10.1007/s11064-005-9029-z] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2005] [Indexed: 11/26/2022]
Abstract
Elevated plasma amyloid beta 1-42 (Abeta42) level has been linked to increased risk for incident AD in cognitively-intact elderly. However, plasma Abeta levels in individuals with late-life depression (LLMD), especially those with a late age of onset of first depressive episode, who are at a particularly increased risk for Alzheimer's disease, have not been studied. We compared plasma Abeta in 47 elderly with LLMD with 35 controls and examined its relationships to age of onset of first depressive episode, antidepressant treatment (paroxetine or nortriptyline), and indices of platelet activation (platelet factor 4 and beta-thromboglobulin) and brain abnormalities. Results indicated that plasma Abeta42 levels and the Abeta42/40 ratio were elevated in the LLMD group relative to controls in the overall group analyses and in the age- and gender-matched groups. MRI data indicated that higher Abeta42/40 ratio was associated with greater severity of total white matter hyperintensity burden in LLMD. Plasma Abeta levels in LLMD were not influenced by age of onset of first depressive episode or antidepressant treatment and were not related to indices of platelet activation. Our preliminary results suggest that increased plasma Abeta42 and Abeta42/40 ratio are present in geriatric depression, and future studies should be done to confirm these findings and to determine their relationship to cognitive decline and brain abnormalities associated with LLMD.
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Affiliation(s)
- Nunzio Pomara
- Geriatric Psychiatry Program, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA.
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Frey HJ, Mattila KM, Korolainen MA, Pirttilä T. Problems associated with biological markers of Alzheimer's disease. Neurochem Res 2006; 30:1501-10. [PMID: 16362769 DOI: 10.1007/s11064-005-8827-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/09/2005] [Indexed: 11/26/2022]
Abstract
The etiopathogenesis of Alzheimer's disease (AD) is still unclear, although clinical diagnostic criteria exist and the neuropathology of AD has been studied in great detail during the last 20 years. The present study addresses certain problems in the search for biological markers for the diagnosis, as well as in the follow-up of the course of AD and its differential diagnosis and reports some of our own observations in comparison with other studies. These include protein, genetic and neuroimaging markers. The definitions of biological markers and search strategies are also discussed.
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Affiliation(s)
- H J Frey
- Brain Research Center, University of Tampere, Medical School, Building B, FIN-33014, Tampere, Finland.
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Blain JF, Sullivan PM, Poirier J. A deficit in astroglial organization causes the impaired reactive sprouting in human apolipoprotein E4 targeted replacement mice. Neurobiol Dis 2006; 21:505-14. [PMID: 16171999 DOI: 10.1016/j.nbd.2005.08.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2005] [Revised: 08/23/2005] [Accepted: 08/26/2005] [Indexed: 10/25/2022] Open
Abstract
The epsilon4 allele of apolipoprotein (apo)E associates with an increased risk of developing Alzheimer's disease (AD) as well as an earlier age of onset. However, the exact mechanisms by which apoE4 confers such susceptibility is currently unknown. We used a human apoE targeted replacement (hE-TR) mouse model to investigate the allele-specific response to entorhinal cortex lesion (ECL). We observed a marked impairment in reactive sprouting in hE4 mice compared to hE3 mice. ApoE expression was similar between genotypes at days post-lesion (DPL) 2 and 14. Thirty days post-lesion, hE4 mice had more reactive astrocytes as well as a defective outward migration pattern of the astrocytes in the dentate gyrus. The expression of the anti-inflammatory cytokine IL-1ra was delayed in hE4 mice compared to hE3 mice. ApoE and beta-amyloid (Abeta) 1-40 accumulated at 30 DPL in hE4 mice. These results suggest that the presence of apoE4 delays the astroglial repair process and indirectly compromises synaptic remodeling.
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Affiliation(s)
- Jean-François Blain
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada H4A 2B4
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Bartha JL, Soothill PW. Plasma amyloid beta protein 1-42 levels in fetuses with Down syndrome. Early Hum Dev 2005; 81:351-4. [PMID: 15814219 DOI: 10.1016/j.earlhumdev.2004.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2004] [Revised: 09/01/2004] [Accepted: 09/02/2004] [Indexed: 11/23/2022]
Abstract
BACKGROUND The presence of amyloid plaques in the brains of people with Down syndrome is correlated with the severity and the progression of the disease. The core of the plaques is an amyloid beta (A beta) protein. If a relationship between fetal levels and the presence and severity of the disease could be determined, consideration of an early intervention to reduce brain damage can be proposed. AIM To study plasma amyloid beta 1-42 levels in fetuses with Down syndrome. STUDY DESIGN Fetal plasma amyloid beta 1-42 levels were measured using a commercially available immunoassay. The sample size was previously calculated to show a difference with an alpha level of 0.05 and a power (1-beta) of 90%. SUBJECTS Thirteen fetuses with Down syndrome and 17 controls (22.3+/-2.0 and 21.6+/-1.2 weeks of gestation, respectively). OUTCOME MEASURES Fetal plasma amyloid beta 1-42 levels. RESULTS There was no significant difference in plasma amyloid beta 1-42 levels between fetuses with Down syndrome and those with a normal karyotype (193.1+/-48.0 vs. 194.6+/-15.6 pg/mL, respectively). CONCLUSIONS This result does not support the hypothesis that A beta 1-42 may be related to the severity of brain damage in newborns with Down syndrome. The high levels of this peptide in fetuses without Down syndrome favour a physiological role of these peptides during brain development.
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Affiliation(s)
- Jose L Bartha
- Fetal Medicine Research Unit, Department of Obstetrics and Gynaecology, St Michael's Hospital, University of Bristol, Bristol, UK.
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Moir RD, Tseitlin KA, Soscia S, Hyman BT, Irizarry MC, Tanzi RE. Autoantibodies to redox-modified oligomeric Abeta are attenuated in the plasma of Alzheimer's disease patients. J Biol Chem 2005; 280:17458-63. [PMID: 15728175 DOI: 10.1074/jbc.m414176200] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Accumulation of Abeta protein in beta-amyloid deposits is a hallmark event in Alzheimer's disease (AD). Recent findings suggest anti-Abeta autoantibodies may have a role in AD pathology. However, a consensus has yet to emerge as to whether endogenous anti-Abeta autoantibodies are elevated, depressed, or unchanged in AD patients. Whereas experiments to date have used synthetic unmodified monomeric Abeta (Abetamon) to test autoimmunity, up to 40% of the Abeta pool inB AD brain consists of low molecular weight oligomeric cross-linked beta-amyloid protein species (CAPS). Recent studies also suggest that CAPS may be the primary neurotoxic agent in AD. In the present study, AD and nondemented control plasma were analyzed for immunoreactivity to CAPS and Abetamon. Plasma of both nondemented and AD patients were found to contain autoantibodies specific for soluble CAPS. Nondemented control and AD plasmas demonstrated similar immunoreactivity to Abetamon. In contrast, anti-CAPS antibodies in AD plasma were found to be significantly reduced compared with nondemented controls (p=0.018). Furthermore, age at onset for AD correlated significantly (p=0.041) with plasma immunoreactivity to CAPS. These data suggest that autoantibodies to CAPS are depleted in AD patients and raise the prospect that immunization with anti-CAPS antibodies might provide therapeutic benefit for AD.
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Affiliation(s)
- Robert D Moir
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital and Harvard Medical School, Charlestown 02129-4404, USA
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Noda-Saita K, Terai K, Iwai A, Tsukamoto M, Shitaka Y, Kawabata S, Okada M, Yamaguchi T. Exclusive association and simultaneous appearance of congophilic plaques and AT8-positive dystrophic neurites in Tg2576 mice suggest a mechanism of senile plaque formation and progression of neuritic dystrophy in Alzheimer's disease. Acta Neuropathol 2004; 108:435-42. [PMID: 15372280 DOI: 10.1007/s00401-004-0907-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2004] [Revised: 06/25/2004] [Accepted: 06/28/2004] [Indexed: 11/26/2022]
Abstract
Progression of neuritic dystrophy is a histological hallmark of Alzheimer's disease (AD) in addition to amyloid deposition and neurofibrillary tangle formation. Dystrophic neurites (DNs) are abnormal neurites, and are closely associated with amyloid deposits. To clarify the process of DN formation, we immunohistochemically investigated phosphorylated tau (AT8 and Ser396)-positive DNs and plaques in Tg2576 mice overexpressing human beta-amyloid precursor protein (APP) with the Swedish type mutation (K670N/M671L). AT8-positive DNs were exclusively associated with the Congo red-positive plaques examined, and all Abeta(1-40)-positive plaques appeared to be associated with AT8-positive DNs, whereas there were no AT8-positive DNs with Abeta(1-42)-positive/Abeta(1-40)-negative plaques. Since we have previously shown that Abeta(1-42)-positive plaque precede Abeta(1-40) deposition, the appearance of congophilic structures is also late. Quantitative analyses were performed on AT8-positive DNs that were associated with congophilic plaques in the cerebral cortex and hippocampus (more than 1,000 plaques). The number of congophilic plaques increased dramatically with age. The area of DNs in the cerebral cortex and hippocampus increased 120- and 60-fold from 11-13 to 20.5 months of age, respectively. Interestingly, the mean ratio of DN area to congophilic plaque area in every plaque was unchanged, approximately 10%, through the ages examined. The mean plaque size was stable with age in both the cortex and hippocampus. These data suggest that the formation of AT8-positive DNs is simultaneous with Congo red-positive plaque development, and that the event may be closely related in the pathological progression of AD.
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Affiliation(s)
- Kyoko Noda-Saita
- Neuroscience Research, Yamanouchi Pharmaceutical Company Limited, 21 Miyukigaoka, Tsukuba, 305-8585 Ibaraki, Japan.
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Abstract
PURPOSE OF REVIEW Exciting new therapeutic approaches to the treatment or prevention of Alzheimer's disease involve preventing, slowing or reversing beta-amyloid accumulation. These interventions may also apply to the treatment of Alzheimer's disease in Down syndrome. The purpose of the current review is therefore to summarize developments and advances in our understanding of beta-amyloid pathogenesis in Down syndrome over the past year. RECENT FINDINGS A shift in research to a focus on early events in beta-amyloid pathogenesis in Down syndrome has led to several novel observations. Several authors have reported the accumulation of both soluble and intracellular beta-amyloid before extracellular beta-amyloid (senile plaques) in Down syndrome. Increases in beta-amyloid levels in Down syndrome may reflect the increased expression and protein levels of beta-site amyloid precursor protein cleavage enzyme 2 on chromosome 21. The impact of the accumulation of beta-amyloid may have differential effects on development and aging in Down syndrome. SUMMARY The past year has seen significant advances in our understanding of beta-amyloid pathogenesis and the functional consequences of beta-amyloid accumulation in Down syndrome. However, there are still large gaps in our knowledge of the pathways involved in beta-amyloid degradation and clearance. It will be critical to conduct clinical trials to test therapeutic strategies that may reduce beta-amyloid in Down syndrome directly to determine the optimal age and dose for specific interventions. Given the differences in the mechanism of beta-amyloid accumulation in Down syndrome, careful consideration needs to be given to potential clinical trials to treat this disorder.
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Affiliation(s)
- Elizabeth Head
- Institute for Brain Aging and Dementia, Department of Neurology, University of California, Irvine, California, USA.
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Bowen RL, Verdile G, Liu T, Parlow AF, Perry G, Smith MA, Martins RN, Atwood CS. Luteinizing hormone, a reproductive regulator that modulates the processing of amyloid-beta precursor protein and amyloid-beta deposition. J Biol Chem 2004; 279:20539-45. [PMID: 14871891 DOI: 10.1074/jbc.m311993200] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hormonal changes associated with the dysregulation of the hypothalamic-pituitary-gonadal (HPG) axis following menopause/andropause have been implicated in the pathogenesis of Alzheimer's disease (AD). Experimental support for this has come from studies demonstrating an increase in amyloid-beta (Abeta) deposition following ovariectomy/castration. Because sex steroids and gonadotropins are both part of the HPG feedback loop, any loss in sex steroids results in a proportionate increase in gonadotropins. To assess whether Abeta generation was due to the loss of serum 17beta-estradiol or to the up-regulation of serum gonadotropins, we treated C57Bl/6J mice with the anti-gonadotropin leuprolide acetate, which suppresses both sex steroids and gonadotropins. Leuprolide acetate treatment resulted in a 3.5-fold (p < 0.0001) and a 1.5-fold (p < 0.024) reduction in total brain Abeta1-42 and Abeta1-40 concentrations, respectively, after 8 weeks of treatment. To further explore the role of gonadotropins in promoting amyloidogenesis, M17 neuroblastoma cells were treated with the gonadotropin luteinizing hormone (LH) at concentrations equivalent to early adulthood (10 mIU/ml) or post-menopause/andropause (30 mIU/ml). LH did not alter amyloid-beta precursor protein (AbetaPP) expression but did alter AbetaPP processing toward the amyloidogenic pathway as evidenced by increased secretion and insolubility of Abeta, decreased alphaAbetaPP secretion, and increased AbetaPP-C99 levels. These results suggest the marked increases in serum LH following menopause/andropause as a physiologically relevant signal that could promote Abeta secretion and deposition in the aging brain. Suppression of the age-related increase in serum gonadotropins using anti-gonadotropin agents may represent a novel therapeutic strategy for AD.
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Lanz TA, Hosley JD, Adams WJ, Merchant KM. Studies of Aβ Pharmacodynamics in the Brain, Cerebrospinal Fluid, and Plasma in Young (Plaque-Free) Tg2576 Mice Using the γ-Secretase Inhibitor N2-[(2S)-2-(3,5-Difluorophenyl)-2-hydroxyethanoyl]-N1-[(7S)-5-methyl-6-oxo-6,7-dihydro-5H-dibenzo[b,d]azepin-7-yl]-L-alaninamide (LY-411575). J Pharmacol Exp Ther 2004; 309:49-55. [PMID: 14718585 DOI: 10.1124/jpet.103.060715] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A previous study by us suggests the utility of cerebrospinal fluid (CSF) and plasma Abeta as biomarkers of beta- or gamma-secretase inhibition. The present study characterized further Abeta pharmacodynamics in these tissues from Tg2576 mice and examined their correlation with brain Abeta after acute treatment with a potent gamma-secretase inhibitor, N(2)-[(2S)-2-(3,5-difluorophenyl)-2-hydroxyethanoyl]-N(1)-[(7S)-5-methyl-6-oxo-6,7-dihydro-5H-dibenzo[b,d]azepin-7-yl]-l-alaninamide (LY-411575). A single dose of LY-411575 dose-dependently (0.1-10 mg/kg p.o.) reduced Abeta(1-40) and Abeta(1-42) in the CSF and the brain. In contrast, plasma Abeta levels were increased by 0.1 mg/kg LY-411575 and were followed by a dose-dependent reduction at higher doses. The time courses of Abeta reduction and recovery were distinct for the three tissues: maximal declines in Abeta levels were evident by 3 h in the CSF and plasma but not until 9 h in the brain. A recovery in Abeta levels was underway in the CSF by 9 h and nearly completed by 24 h in all tissues. The differential time courses in the three compartments do not seem to be due to pharmacokinetic factors. Five days of twice-daily treatment with LY-411575 not only sustained the Abeta reductions in all tissues but also significantly augmented the efficacy in the brain and plasma. The increased efficacy occurred in the absence of compound accumulation and was consistent with the recovery rates in each compartment. Overall, Abeta in the CSF and not plasma seems to be a better biomarker of brain Abeta reduction; however, the time course of Abeta changes needs to be established in clinical studies.
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Affiliation(s)
- Thomas A Lanz
- Pfizer Inc., Eastern Point Road, MS# 8220-4183, Groton, CT 06340, USA.
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Miklossy J, Taddei K, Suva D, Verdile G, Fonte J, Fisher C, Gnjec A, Ghika J, Suard F, Mehta PD, McLean CA, Masters CL, Brooks WS, Martins RN. Two novel presenilin-1 mutations (Y256S and Q222H) are associated with early-onset Alzheimer's disease. Neurobiol Aging 2003; 24:655-62. [PMID: 12885573 DOI: 10.1016/s0197-4580(02)00192-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Mutations in the gene encoding presenilin 1 (PS-1) account for 50% of early-onset familial Alzheimer's disease (EOFAD) cases. In this study, we identified two missense mutations in the coding sequence of the presenilin (PS-1) gene in two EOFAD pedigrees. AD was confirmed in one pedigree by autopsy. Mutation analysis of PCR products amplified from genomic DNA templates showed two novel PS-1 mutations resulting in Gln222His and Tyr256Ser. The two novel mutations are located within predicted transmembrane domains five (TM-5) and six (TM-6), respectively, and are associated with very early ages of onset. The Tyr256Ser is associated with one of the youngest age of AD onset, 25 years, which is consistent with a drastic change in function of the altered PS-1 protein. A morphometric analysis of the cortical degenerative changes of the Tyr256Ser case, showed severe involvement of the primary motor cortex, which correlated well with the pyramidal changes, including tetraspasticity. Immunoblot analysis showed the Tyr256Ser case had the greatest expression of Abeta(1-40) and Abeta(1-42), which was confirmed by ELISA, compared to other PS-1 mutant FAD cases and age-matched controls and, thus, contributes to the severity of the disease pathology.
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Affiliation(s)
- Judith Miklossy
- Centre for Neurovirology and Cancer Biology, College of Science and Technology, Temple University, Philadelphia, PA 19122, USA
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Mehta PD, Mehta SP, Fedor B, Patrick BA, Emmerling M, Dalton AJ. Plasma amyloid beta protein 1-42 levels are increased in old Down Syndrome but not in young Down Syndrome. Neurosci Lett 2003; 342:155-8. [PMID: 12757888 DOI: 10.1016/s0304-3940(03)00275-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Plasma amyloid beta protein 1-40 (Abeta40) and Abeta42 levels were quantitated from 28 young Down syndrome (DS) (20-40 years old), 28 age-matched controls, 32 old DS (41-65 years old) and 32 age-matched controls in a sandwich enzyme-linked immunosorbent assay. Abeta40 levels were higher in young DS and old DS than controls. Abeta42 levels in young DS and controls were similar, however Abeta42 levels were higher in old DS than controls or young DS. The higher Abeta42 levels in old DS suggests that Abeta42 is selectively increased in plasma concurrently with the development of Alzheimer disease neuropathology.
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Affiliation(s)
- Pankaj D Mehta
- Division of Immunology, Department of Developmental Neurobiology, Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314-6399, USA.
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Pomara N, Murali Doraiswamy P. Does increased platelet release of Abeta peptide contribute to brain abnormalities in individuals with depression? Med Hypotheses 2003; 60:640-3. [PMID: 12710895 DOI: 10.1016/s0306-9877(02)00380-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Increased platelet activation with release of procoagulant factors from their alpha granules has been demonstrated in individuals with major depression. Platelet activation has also been shown to be associated with release of beta-amyloid peptides, which have been implicated in Alzheimer's disease. Thus, we are hypothesizing that sustained elevations of Abeta peptides might occur in individuals with recurrent depression. We further hypothesize that such elevations contribute to brain abnormalities in depressed individuals through the formation of neurotoxic oligomeric forms of Abeta peptides and amyloid deposition. We also propose that increased amyloid Abeta peptides from platelet activation may be a mechanism underlying the increased risk for cognitive impairment in nondepressed patients who have other reasons for such activation. If true, our hypothesis would imply that platelet inhibitors may have a role in preventing or delaying the neuronal consequences of disorders characterized by activated platelets.
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Affiliation(s)
- Nunzio Pomara
- Department of Psychiatry, New York University School of Medicine, USA.
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Tammer AH, Coia G, Cappai R, Fuller S, Masters CL, Hudson P, Underwood JR. Generation of a recombinant Fab antibody reactive with the Alzheimer's disease-related Abeta peptide. Clin Exp Immunol 2002; 129:453-63. [PMID: 12197886 PMCID: PMC1906481 DOI: 10.1046/j.1365-2249.2002.01905.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/10/2002] [Indexed: 12/31/2022] Open
Abstract
A recombinant Fab antibody, designated 1E8-4b, which reacts with the Alzheimer's disease (AD)-related Abeta peptides, Abeta[1-40], Abeta[1-42] and Abeta[1-43] has been developed. The 1E8-4b Fab was constructed by cloning the V(H)C(H1) and V(L)C(L) domains from the parent hybridoma 1E8 antibody, reported previously to recognize these Abeta peptides. Briefly, a C-terminal Flag tag sequence was incorporated into this construct, which was ligated into the vector pHFA2 and expressed in Escherichia coli. Following purification on an M2 anti-Flag affinity column, the 1E8-4b recombinant Fab antibody was shown to bind plaques within sections of brain tissue from CERAD-defined AD patients by immunohistochemistry. ELISA, epitope mapping and immunoblotting confirmed the recognition of the Abeta1-40/42/43] peptides by the 1E8-4b Fab. The 1E8-4b Fab did not recognize APP695 or APP770 which contain the Abeta sequence. The Abeta specificity of the recombinant 1E8-4b Fab antibody was identical to the parent 1E8 monoclonal antibody.
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Affiliation(s)
- A H Tammer
- Department of Pathology, Melbourne University, Parkville, Victoria, Australia
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Li J, Pauley AM, Myers RL, Shuang R, Brashler JR, Yan R, Buhl AE, Ruble C, Gurney ME. SEL-10 interacts with presenilin 1, facilitates its ubiquitination, and alters A-beta peptide production. J Neurochem 2002; 82:1540-8. [PMID: 12354302 DOI: 10.1046/j.1471-4159.2002.01105.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mutations in the human presenilin genes (PS1 or PS2) have been linked to autosomal dominant, early onset Alzheimer's disease (AD). Presenilins, probably as an essential part of gamma-secretase, modulate gamma-cleavage of the amyloid protein precursor (APP) to the amyloid beta-peptide (Abeta). Mutations in sel-12, a Caenorhabditis elegans presenilin homologue, cause a defect in egg laying that can be suppressed by loss of function mutations in a second gene, SEL-10. SEL-10 protein is a homologue of yeast Cdc4, a member of the SCF (Skp1-Cdc53/CUL1-F-box protein) E2-E3 ubiquitin ligase family. In this study, we show that human SEL-10 interacts with PS1 and enhances PS1 ubiquitination, thus altering cellular levels of unprocessed PS1 and its N- and C-terminal fragments. Co-transfection of sel-10 and APP cDNAs in HEK293 cells leads to an alteration in the metabolism of APP and to an increase in the production of amyloid beta-peptide, the principal component of amyloid plaque in Alzheimer's disease.
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Affiliation(s)
- Jinhe Li
- Department of Neurobiology, Computer Aided Drug Design, Pharmacia Corporation, Kalamazoo, Michigan 49001, USA
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