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Singh CSB, Johns KM, Kari S, Munro L, Mathews A, Fenninger F, Pfeifer CG, Jefferies WA. Conclusive demonstration of iatrogenic Alzheimer's disease transmission in a model of stem cell transplantation. Stem Cell Reports 2024; 19:456-468. [PMID: 38552634 PMCID: PMC11096610 DOI: 10.1016/j.stemcr.2024.02.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 04/12/2024] Open
Abstract
The risk of iatrogenic disease is often underestimated as a concern in contemporary medical procedures, encompassing tissue and organ transplantation, stem cell therapies, blood transfusions, and the administration of blood-derived products. In this context, despite the prevailing belief that Alzheimer's disease (AD) manifests primarily in familial and sporadic forms, our investigation reveals an unexpected transplantable variant of AD in a preclinical context, potentially indicating iatrogenic transmission in AD patients. Through adoptive transplantation of donor bone marrow stem cells carrying a mutant human amyloid precursor protein (APP) transgene into either APP-deficient knockout or normal recipient animals, we observed rapid development of AD pathological hallmarks. These pathological features were significantly accelerated and emerged within 6-9 months post transplantation and included compromised blood-brain barrier integrity, heightened cerebral vascular neoangiogenesis, elevated brain-associated β-amyloid levels, and cognitive impairment. Furthermore, our findings underscore the contribution of β-amyloid burden originating outside of the central nervous system to AD pathogenesis within the brain. We conclude that stem cell transplantation from donors harboring a pathogenic mutant allele can effectively transfer central nervous system diseases to healthy recipients, mirroring the pathogenesis observed in the donor. Consequently, our observations advocate for genomic sequencing of donor specimens prior to tissue, organ, or stem cell transplantation therapies, as well as blood transfusions and blood-derived product administration, to mitigate the risk of iatrogenic diseases.
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Affiliation(s)
- Chaahat S B Singh
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC V6T 1Z4, Canada; The Vancouver Prostate Centre, Vancouver General Hospital, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada; Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada; The Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC V6T 1Z4, Canada; Department of Medical Genetics, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada
| | - Kelly Marie Johns
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC V6T 1Z4, Canada; The Vancouver Prostate Centre, Vancouver General Hospital, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada; Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada; The Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC V6T 1Z4, Canada; Department of Medical Genetics, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada
| | - Suresh Kari
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC V6T 1Z4, Canada; The Vancouver Prostate Centre, Vancouver General Hospital, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada; Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada; The Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC V6T 1Z4, Canada; Department of Medical Genetics, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada
| | - Lonna Munro
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC V6T 1Z4, Canada; The Vancouver Prostate Centre, Vancouver General Hospital, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada; Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada; The Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC V6T 1Z4, Canada
| | - Angela Mathews
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC V6T 1Z4, Canada; The Vancouver Prostate Centre, Vancouver General Hospital, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada; Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada; The Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC V6T 1Z4, Canada; Department of Medical Genetics, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada
| | - Franz Fenninger
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC V6T 1Z4, Canada; The Vancouver Prostate Centre, Vancouver General Hospital, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada; Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada; The Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC V6T 1Z4, Canada; Department of Microbiology and Immunology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada
| | - Cheryl G Pfeifer
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC V6T 1Z4, Canada; The Vancouver Prostate Centre, Vancouver General Hospital, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada; Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada; The Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC V6T 1Z4, Canada
| | - Wilfred A Jefferies
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC V6T 1Z4, Canada; The Vancouver Prostate Centre, Vancouver General Hospital, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada; Centre for Blood Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada; The Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC V6T 1Z4, Canada; Department of Medical Genetics, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada; Department of Microbiology and Immunology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z4, Canada; Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada; Department of Urologic Sciences, University of British Columbia, Level 6, 2775 Laurel Street, Vancouver, BC V5Z 1M9 Canada.
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Sukreet S, Rafii MS, Rissman RA. From understanding to action: Exploring molecular connections of Down syndrome to Alzheimer's disease for targeted therapeutic approach. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2024; 16:e12580. [PMID: 38623383 PMCID: PMC11016820 DOI: 10.1002/dad2.12580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 03/05/2024] [Accepted: 03/08/2024] [Indexed: 04/17/2024]
Abstract
Down syndrome (DS) is caused by a third copy of chromosome 21. Alzheimer's disease (AD) is a neurodegenerative condition characterized by the deposition of amyloid-beta (Aβ) plaques and neurofibrillary tangles in the brain. Both disorders have elevated Aβ, tau, dysregulated immune response, and inflammation. In people with DS, Hsa21 genes like APP and DYRK1A are overexpressed, causing an accumulation of amyloid and neurofibrillary tangles, and potentially contributing to an increased risk of AD. As a result, people with DS are a key demographic for research into AD therapeutics and prevention. The molecular links between DS and AD shed insights into the underlying causes of both diseases and highlight potential therapeutic targets. Also, using biomarkers for early diagnosis and treatment monitoring is an active area of research, and genetic screening for high-risk individuals may enable earlier intervention. Finally, the fundamental mechanistic parallels between DS and AD emphasize the necessity for continued research into effective treatments and prevention measures for DS patients at risk for AD. Genetic screening with customized therapy approaches may help the DS population in current clinical studies and future biomarkers.
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Affiliation(s)
- Sonal Sukreet
- Department of NeurosciencesUniversity of California‐San DiegoLa JollaCaliforniaUSA
| | - Michael S. Rafii
- Department of Neurology, Alzheimer's Therapeutic Research InstituteKeck School of Medicine of the University of Southern CaliforniaSan DiegoCaliforniaUSA
| | - Robert A. Rissman
- Department of NeurosciencesUniversity of California‐San DiegoLa JollaCaliforniaUSA
- Department Physiology and Neuroscience, Alzheimer’s Therapeutic Research InstituteKeck School of Medicine of the University of Southern CaliforniaSan DiegoCaliforniaUSA
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Henrique AM, Gianetti NG, Ferrari MFR. Parkin is downregulated among autophagy-related proteins prior to hyperphosphorylation of Tau in TS65DN mice. Biochem Biophys Res Commun 2021; 561:59-64. [PMID: 34015759 DOI: 10.1016/j.bbrc.2021.05.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 05/07/2021] [Indexed: 10/21/2022]
Abstract
Autophagy is a pathway through which cells execute a plethora of functions, such as macromolecules and organelles quality control, recycling of building blocks and apoptosis. Numerous studies have shown in the past that autophagy is an important mechanism associated with the pathology of various neurodegenerative diseases, whose impairment may lead to several disease-characteristic phenotypes (e.g. misfolded protein and defective organelles accumulation). With this in mind, we aimed to investigate whether alterations in expression of autophagy-related proteins would show before hyperphosphorylation of Tau, a hallmark of Alzheimer's disease (AD). After analyzing 7 different proteins, we observed that, while Pink1 and p62 show an age-related reduction in the Ts65Dn mice respectively in the locus coeruleus and hippocampus, Parkin shows an age-genotype interaction-associated reduction in both brain areas. This suggests potential outcomes in pathways associated with Parkin that could relate to later stages of the disease development.
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Affiliation(s)
- Alan M Henrique
- Departamento de Genetica e Biologia Evolutiva, Instituto de Biociencias. Universidade de Sao Paulo, Sao Paulo, SP, Brazil.
| | - Nathália G Gianetti
- Departamento de Genetica e Biologia Evolutiva, Instituto de Biociencias. Universidade de Sao Paulo, Sao Paulo, SP, Brazil
| | - Merari F R Ferrari
- Departamento de Genetica e Biologia Evolutiva, Instituto de Biociencias. Universidade de Sao Paulo, Sao Paulo, SP, Brazil
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Differential effects of chronic immunosuppression on behavioral, epigenetic, and Alzheimer's disease-associated markers in 3xTg-AD mice. ALZHEIMERS RESEARCH & THERAPY 2021; 13:30. [PMID: 33472690 PMCID: PMC7818784 DOI: 10.1186/s13195-020-00745-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 12/07/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND Circulating autoantibodies and sex-dependent discrepancy in prevalence are unexplained phenomena of Alzheimer's disease (AD). Using the 3xTg-AD mouse model, we reported that adult males show early manifestations of systemic autoimmunity, increased emotional reactivity, enhanced expression of the histone variant macroH2A1 in the cerebral cortex, and loss of plaque/tangle pathology. Conversely, adult females display less severe autoimmunity and retain their AD-like phenotype. This study examines the link between immunity and other traits of the current 3xTg-AD model. METHODS Young 3xTg-AD and wild-type mice drank a sucrose-laced 0.4 mg/ml solution of the immunosuppressant cyclophosphamide on weekends for 5 months. After behavioral phenotyping at 2 and 6 months of age, we assessed organ mass, serologic markers of autoimmunity, molecular markers of early AD pathology, and expression of genes associated with neurodegeneration. RESULTS Chronic immunosuppression prevented hematocrit drop and reduced soluble Aβ in 3xTg-AD males while normalizing the expression of histone variant macroH2A1 in 3xTg-AD females. This treatment also reduced hepatosplenomegaly, lowered autoantibody levels, and increased the effector T cell population while decreasing the proportion of regulatory T cells in both sexes. Exposure to cyclophosphamide, however, neither prevented reduced brain mass and BDNF expression nor normalized increased tau and anxiety-related behaviors. CONCLUSION The results suggest that systemic autoimmunity increases soluble Aβ production and affects transcriptional regulation of macroH2A1 in a sex-related manner. Despite the complexity of multisystem interactions, 3xTg-AD mice can be a useful in vivo model for exploring the regulatory role of autoimmunity in the etiology of AD-like neurodegenerative disorders.
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Rueda N, Flórez J, Dierssen M, Martínez-Cué C. Translational validity and implications of pharmacotherapies in preclinical models of Down syndrome. PROGRESS IN BRAIN RESEARCH 2019; 251:245-268. [PMID: 32057309 DOI: 10.1016/bs.pbr.2019.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Neurodevelopmental disorders are challenging to study in the laboratory, and despite a large investment, few novel treatments have been developed in the last decade. While animal models have been valuable in elucidating disease mechanisms and in providing insights into the function of specific genes, the predictive validity of preclinical models to test potential therapies has been questioned. In the last two decades, diverse new murine models of Down syndrome (DS) have been developed and numerous studies have demonstrated neurobiological alterations that could be responsible for the cognitive and behavioral phenotypes found in this syndrome. In many cases, similar alterations were found in murine models and in individuals with DS, although several phenotypes shown in animals have yet not been confirmed in the human condition. Some of the neurobiological alterations observed in mice have been proposed to account for their changes in cognition and behavior, and have received special attention because of being putative therapeutic targets. Those include increased oxidative stress, altered neurogenesis, overexpression of the Dyrk1A gene, GABA-mediated overinhibition and Alzheimer's disease-related neurodegeneration. Subsequently, different laboratories have tested the efficacy of pharmacotherapies targeting these alterations. Unfortunately, animal models are limited in their ability to mimic the extremely complex process of human neurodevelopment and neuropathology. Therefore, the safety and efficacy identified in animal studies are not always translated to humans, and most of the drugs tested have not demonstrated any positive effect or very limited efficacy in clinical trials. Despite their limitations, though, animal trials give us extremely valuable information for developing and testing drugs for human use that cannot be obtained from molecular or cellular experiments alone. This chapter reviews some of these therapeutic approaches and discusses some reasons that could account for the discrepancy between the findings in mouse models of DS and in humans, including: (i) the incomplete resemble of the genetic alterations of available mouse models of DS and human trisomy 21, (ii) the lack of evidence that some of the phenotypic alterations found in mice (e.g., GABA-mediated overinhibition, and alterations in adult neurogenesis) are also present in DS individuals, and (iii) the inaccuracy and/or inadequacy of the methods used in clinical trials to detect changes in the cognitive and behavioral functions of people with DS. Despite the shortcomings of animal models, animal experimentation remains an invaluable tool in developing drugs. Thus, we will also discuss how to increase predictive validity of mouse models.
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Affiliation(s)
- Noemí Rueda
- Department of Physiology and Pharmacology, University of Cantabria, Santander, Spain
| | - Jesús Flórez
- Department of Physiology and Pharmacology, University of Cantabria, Santander, Spain
| | - Mara Dierssen
- Cellular and Systems Neurobiology, Systems Biology Program, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Carmen Martínez-Cué
- Department of Physiology and Pharmacology, School of Medicine, University of Cantabria, Santander, Spain.
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Roper RJ, Hawley L, Goodlett CR. Influence of allelic differences in Down syndrome. PROGRESS IN BRAIN RESEARCH 2019; 251:29-54. [PMID: 32057311 PMCID: PMC7500172 DOI: 10.1016/bs.pbr.2019.09.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Both trisomic and non-trisomic genes may affect the incidence and severity of phenotypes associated with Down syndrome (DS). The importance of extra (trisomic) genetic material is emphasized in DS, with less emphasis to the allelic composition of candidate trisomic genes in defining the trisomic gene-phenotype relationship in DS. Allelic differences in non-trisomic genes have been shown to be important moderators of cardiac, leukemia, and developmental phenotypes associated with DS. Trisomic mouse models provide an in vivo genetic platform for examining the gene-phenotype relationship, including the influence of allelic variants, on DS-like phenotypes. DS mouse models have differing trisomic genetic makeup, and optimal development, viability and translational value of these mouse models may require a non-inbred genetic background with heterogeneity at many loci. Additionally, understanding the contribution of specific genes or regions to DS phenotypes often requires the utilization of genetically manipulated mice that may be established on a different inbred background than the trisomic mice. The impact of allelic differences of trisomic and background genes in human and model systems may offer insight into the variability in occurrence and severity of trisomic phenotypes.
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Affiliation(s)
- Randall J Roper
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States.
| | - Laura Hawley
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| | - Charles R Goodlett
- Department of Psychology, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
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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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D'Acunzo P, Hargash T, Pawlik M, Goulbourne CN, Pérez-González R, Levy E. Enhanced generation of intraluminal vesicles in neuronal late endosomes in the brain of a Down syndrome mouse model with endosomal dysfunction. Dev Neurobiol 2019; 79:656-663. [PMID: 31278881 DOI: 10.1002/dneu.22708] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 07/01/2019] [Accepted: 07/02/2019] [Indexed: 12/22/2022]
Abstract
Down syndrome (DS) is a human genetic disease caused by trisomy of chromosome 21 and characterized by early developmental brain abnormalities. Dysfunctional endosomal pathway in neurons is an early event of DS and Alzheimer's disease. Recently, we have demonstrated that exosome secretion is upregulated in human DS postmortem brains, in the brain of the trisomic mouse model Ts[Rb(12.1716 )]2Cje (Ts2) and by DS fibroblasts as compared with disomic controls. High levels of the tetraspanin CD63, a regulator of exosome biogenesis, were observed in DS brains. Partially blocking exosome secretion by DS fibroblasts exacerbated a pre-existing early endosomal pathology. We thus hypothesized that enhanced CD63 expression induces generation of intraluminal vesicles (ILVs) in late endosomes/multivesicular bodies (MVBs), increasing exosome release as an endogenous mechanism to mitigate endosomal abnormalities in DS. Herein, we show a high-resolution electron microscopy analysis of MVBs in neurons of the frontal cortex of 12-month-old Ts2 mice and littermate diploid controls. Our quantitative analysis revealed that Ts2 MVBs are larger, more abundant, and contain a higher number of ILVs per neuron compared to controls. These findings were further corroborated biochemically by Western blot analysis of purified endosomal fractions showing higher levels of ILVs proteins in the same fractions containing endosomal markers in the brain of Ts2 mice compared to controls. These data suggest that upregulation of ILVs production may be a key homeostatic mechanism to alleviate endosomal dysregulation via the endosomal-exosomal pathway.
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Affiliation(s)
- Pasquale D'Acunzo
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, New York.,Department of Psychiatry, New York University Langone Health, New York, New York
| | - Tal Hargash
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, New York
| | - Monika Pawlik
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, New York
| | - Chris N Goulbourne
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, New York
| | - Rocío Pérez-González
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, New York.,Department of Psychiatry, New York University Langone Health, New York, New York
| | - Efrat Levy
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, New York.,Department of Psychiatry, New York University Langone Health, New York, New York.,Department of Biochemistry & Molecular Pharmacology, New York University Langone Health, New York, New York.,Neuroscience Institute, New York University Langone Health, New York, New York
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Rossi F, Geiszler PC, Meng W, Barron MR, Prior M, Herd-Smith A, Loreto A, Lopez MY, Faas H, Pardon MC, Conforti L. NAD-biosynthetic enzyme NMNAT1 reduces early behavioral impairment in the htau mouse model of tauopathy. Behav Brain Res 2018; 339:140-152. [PMID: 29175372 PMCID: PMC5769520 DOI: 10.1016/j.bbr.2017.11.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 11/08/2017] [Accepted: 11/22/2017] [Indexed: 11/04/2022]
Abstract
NAD metabolism and the NAD biosynthetic enzymes nicotinamide nucleotide adenylyltransferases (NMNATs) are thought to play a key neuroprotective role in tauopathies, including Alzheimer's disease. Here, we investigated whether modulating the expression of the NMNAT nuclear isoform NMNAT1, which is important for neuronal maintenance, influences the development of behavioral and neuropathological abnormalities in htau mice, which express non-mutant human tau isoforms and represent a model of tauopathy relevant to Alzheimer's disease. Prior to the development of cognitive symptoms, htau mice exhibit tau hyperphosphorylation associated with a selective deficit in food burrowing, a behavior reminiscent to activities of daily living which are impaired early in Alzheimer's disease. We crossed htau mice with Nmnat1 transgenic and knockout mice and tested the resulting offspring until the age of 6 months. We show that overexpression of NMNAT1 ameliorates the early deficit in food burrowing characteristic of htau mice. At 6 months of age, htau mice did not show neurodegenerative changes in both the cortex and hippocampus, and these were not induced by downregulating NMNAT1 levels. Modulating NMNAT1 levels produced a corresponding effect on NMNAT enzymatic activity but did not alter NAD levels in htau mice. Although changes in local NAD levels and subsequent modulation of NAD-dependent enzymes cannot be ruled out, this suggests that the effects seen on behavior may be due to changes in tau phosphorylation. Our results suggest that increasing NMNAT1 levels can slow the progression of symptoms and neuropathological features of tauopathy, but the underlying mechanisms remain to be established.
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Affiliation(s)
- Francesca Rossi
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK; Department of Biomedical Sciences, Cagliari University, Cagliari 09042, Italy
| | - Philippine C Geiszler
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK
| | - Weina Meng
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK
| | - Matthew R Barron
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK
| | - Malcolm Prior
- Department of Biomedical Sciences, Cagliari University, Cagliari 09042, Italy
| | - Anna Herd-Smith
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK
| | - Andrea Loreto
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK
| | - Maria Yanez Lopez
- Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Queen's Medical Centre, Medical School, Nottingham NG7 2UH, UK; Faculty of Medicine, Department of Medicine, Imperial College London, Burlington Danes, Hammersmith campus, London W12 0NN, UK
| | - Henryk Faas
- Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Queen's Medical Centre, Medical School, Nottingham NG7 2UH, UK
| | - Marie-Christine Pardon
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK.
| | - Laura Conforti
- School of Life Sciences, University of Nottingham, Queen's Medical Centre Medical School, Nottingham, NG7 2UH, UK
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Vacano GN, Gibson DS, Turjoman AA, Gawryluk JW, Geiger JD, Duncan M, Patterson D. Proteomic analysis of six- and twelve-month hippocampus and cerebellum in a murine Down syndrome model. Neurobiol Aging 2017; 63:96-109. [PMID: 29245059 DOI: 10.1016/j.neurobiolaging.2017.11.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/09/2017] [Accepted: 11/17/2017] [Indexed: 02/07/2023]
Abstract
This study was designed to investigate the brain proteome of the Ts65Dn mouse model of Down syndrome. We profiled the cerebellum and hippocampus proteomes of 6- and 12-month-old trisomic and disomic mice by difference gel electrophoresis. We quantified levels of 2082 protein spots and identified 272 (170 unique UniProt accessions) by mass spectrometry. Four identified proteins are encoded by genes trisomic in the Ts65Dn mouse. Three of these (CRYZL11, EZR, and SOD1) were elevated with p-value <0.05, and 2 proteins encoded by disomic genes (MAPRE3 and PHB) were reduced. Intergel comparisons based on age (6 vs. 12 months) and brain region (cerebellum vs. hippocampus) revealed numerous differences. Specifically, 132 identified proteins were different between age groups, and 141 identified proteins were different between the 2 brain regions. Our results suggest that compensatory mechanisms exist, which ameliorate the effect of trisomy in the Ts65Dn mice. Differences observed during aging may play a role in the accelerated deterioration of learning and memory seen in Ts65Dn mice.
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Affiliation(s)
- Guido N Vacano
- Knoebel Institute for Healthy Aging, Eleanor Roosevelt Institute, and Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - David S Gibson
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver School of Medicine, Anschutz Medical Campus, Aurora, CO, USA
| | - Abdullah Arif Turjoman
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver School of Medicine, Anschutz Medical Campus, Aurora, CO, USA
| | - Jeremy W Gawryluk
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, USA
| | - Jonathan D Geiger
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, USA
| | - Mark Duncan
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver School of Medicine, Anschutz Medical Campus, Aurora, CO, USA
| | - David Patterson
- Knoebel Institute for Healthy Aging, Eleanor Roosevelt Institute, and Department of Biological Sciences, University of Denver, Denver, CO, USA.
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Gauthier SA, Pérez-González R, Sharma A, Huang FK, Alldred MJ, Pawlik M, Kaur G, Ginsberg SD, Neubert TA, Levy E. Enhanced exosome secretion in Down syndrome brain - a protective mechanism to alleviate neuronal endosomal abnormalities. Acta Neuropathol Commun 2017; 5:65. [PMID: 28851452 PMCID: PMC5576289 DOI: 10.1186/s40478-017-0466-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 08/17/2017] [Indexed: 12/18/2022] Open
Abstract
A dysfunctional endosomal pathway and abnormally enlarged early endosomes in neurons are an early characteristic of Down syndrome (DS) and Alzheimer's disease (AD). We have hypothesized that endosomal material can be released by endosomal multivesicular bodies (MVBs) into the extracellular space via exosomes to relieve neurons of accumulated endosomal contents when endosomal pathway function is compromised. Supporting this, we found that exosome secretion is enhanced in the brains of DS patients and a mouse model of the disease, and by DS fibroblasts. Furthermore, increased levels of the tetraspanin CD63, a regulator of exosome biogenesis, were observed in DS brains. Importantly, CD63 knockdown diminished exosome release and worsened endosomal pathology in DS fibroblasts. Taken together, these data suggest that increased CD63 expression enhances exosome release as an endogenous mechanism mitigating endosomal abnormalities in DS. Thus, the upregulation of exosome release represents a potential therapeutic goal for neurodegenerative disorders with endosomal pathology.
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12
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Rosa E, Mahendram S, Ke YD, Ittner LM, Ginsberg SD, Fahnestock M. Tau downregulates BDNF expression in animal and cellular models of Alzheimer's disease. Neurobiol Aging 2016; 48:135-142. [PMID: 27676333 DOI: 10.1016/j.neurobiolaging.2016.08.020] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 08/03/2016] [Accepted: 08/24/2016] [Indexed: 12/14/2022]
Abstract
In Alzheimer's disease, soluble tau accumulates and deposits as neurofibrillary tangles (NFTs). However, a precise toxic mechanism of tau is not well understood. We hypothesized that overexpression of wild-type tau downregulates brain-derived neurotrophic factor (BDNF), a neurotrophic peptide essential for learning and memory. Two transgenic mouse models of human tau expression and human tau (hTau40)-transfected human neuroblastoma (SH-SY5Y) cells were used to examine the effect of excess or pathologically modified wild-type human tau on BDNF expression. Both transgenic mouse models, with or without NFTs, as well as hTau40-SH-SY5Y cells significantly downregulated BDNF messenger RNA compared with controls. Similarly, transgenic mice overexpressing amyloid-β (Aβ) significantly downregulated BDNF expression. However, when crossed with tau knockout mice, the resulting animals exhibited BDNF levels that were not statistically different from wild-type mice. These results demonstrate that excess or pathologically modified wild-type human tau downregulates BDNF and that neither a mutation in tau nor the presence of NFTs is required for toxicity. Moreover, our findings suggest that tau at least partially mediates Aβ-induced BDNF downregulation. Therefore, Alzheimer's disease treatments targeting Aβ alone may not be effective without considering the impact of tau pathology on neurotrophic pathways.
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Affiliation(s)
- Elyse Rosa
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | - Sujeivan Mahendram
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | - Yazi D Ke
- Dementia Research Unit, The University of New South Wales, Sydney, Australia
| | - Lars M Ittner
- Dementia Research Unit, The University of New South Wales, Sydney, Australia
| | - Stephen D Ginsberg
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA; Department of Psychiatry, New York University Langone Medical Center, Orangeburg, NY, USA; Department of Neuroscience and Physiology, New York University Langone Medical Center, Orangeburg, NY, USA
| | - Margaret Fahnestock
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada.
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13
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Geiszler PC, Barron MR, Pardon MC. Impaired burrowing is the most prominent behavioral deficit of aging htau mice. Neuroscience 2016; 329:98-111. [PMID: 27167086 PMCID: PMC4915442 DOI: 10.1016/j.neuroscience.2016.05.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/03/2016] [Accepted: 05/03/2016] [Indexed: 01/22/2023]
Abstract
htau mice exhibit robust deficits in food burrowing. Behavioral differences between htau and mtau−/− are age-dependent. Before 6 months of age, the htau phenotype is stronger than the mtau−/− phenotype. With aging, the htau phenotype is milder than the mtau−/− phenotype.
htau mice are deficient of murine tau but express all six human tau isoforms, leading to gradual tau misprocessing and aggregation in brain areas relevant to Alzheimer’s disease. While histopathological changes in htau mice have been researched in the past, we focused here on functional consequences of human tau accumulation. htau mice and their background controls – murine tau knock-out (mtau−/−) and C57Bl/6J mice – underwent a comprehensive trial battery to investigate species-specific behavior, locomotor activity, emotional responses, exploratory traits, spatial and recognition memory as well as acquisition, retention and extinction of contextual fear at two, four, six, nine and twelve months of age. In htau mice, tau pathology was already present at two months of age, whereas deficits in food burrowing and spatial working memory were first noted at four months of age. At later stages the presence of human tau on a mtau−/− background appeared to guard cognitive performance; as mtau−/− but not htau mice differed from C57Bl/6J mice in the food burrowing, spontaneous alternation and object discrimination tasks. Aging mtau−/− mice also exhibited increased body mass and locomotor activity. These data highlight that reduced food-burrowing performance was the most robust aspect of the htau phenotype with aging. htau and mtau−/− deficits in food burrowing pointed at the necessity of intact tau systems for daily life activities. While some htau and mtau−/− deficits overlap, age differences between the two genotypes may reflect distinct functional effects and compared to C57Bl/6J mice, the htau phenotype appeared stronger than the mtau−/− phenotype at young ages but milder with aging.
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Affiliation(s)
- Philippine Camilla Geiszler
- Neuroscience Group, School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham NG7 2UH, United Kingdom.
| | - Matthew Richard Barron
- Neuroscience Group, School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham NG7 2UH, United Kingdom.
| | - Marie-Christine Pardon
- Neuroscience Group, School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham NG7 2UH, United Kingdom.
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14
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Hamlett ED, Boger HA, Ledreux A, Kelley CM, Mufson EJ, Falangola MF, Guilfoyle DN, Nixon RA, Patterson D, Duval N, Granholm ACE. Cognitive Impairment, Neuroimaging, and Alzheimer Neuropathology in Mouse Models of Down Syndrome. Curr Alzheimer Res 2016; 13:35-52. [PMID: 26391050 PMCID: PMC5034871 DOI: 10.2174/1567205012666150921095505] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 08/08/2015] [Accepted: 08/20/2015] [Indexed: 11/22/2022]
Abstract
Down syndrome (DS) is the most common non-lethal genetic condition that affects approximately 1 in 700 births in the United States of America. DS is characterized by complete or segmental chromosome 21 trisomy, which leads to variable intellectual disabilities, progressive memory loss, and accelerated neurodegeneration with age. During the last three decades, people with DS have experienced a doubling of life expectancy due to progress in treatment of medical comorbidities, which has allowed this population to reach the age when they develop early onset Alzheimer's disease (AD). Individuals with DS develop cognitive and pathological hallmarks of AD in their fourth or fifth decade, and are currently lacking successful prevention or treatment options for dementia. The profound memory deficits associated with DS-related AD (DS-AD) have been associated with degeneration of several neuronal populations, but mechanisms of neurodegeneration are largely unexplored. The most successful animal model for DS is the Ts65Dn mouse, but several new models have also been developed. In the current review, we discuss recent findings and potential treatment options for the management of memory loss and AD neuropathology in DS mouse models. We also review agerelated neuropathology, and recent findings from neuroimaging studies. The validation of appropriate DS mouse models that mimic neurodegeneration and memory loss in humans with DS can be valuable in the study of novel preventative and treatment interventions, and may be helpful in pinpointing gene-gene interactions as well as specific gene segments involved in neurodegeneration.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Ann-Charlotte E Granholm
- Department Neurosciences, Director, Center on Aging, Medical Univ. South Carolina, Basic Science Bldg, Room 403, 173 Ashley Avenue, Charleston, SC 29425, USA.
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15
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Yang SH, Kim J, Lee MJ, Kim Y. Abnormalities of plasma cytokines and spleen in senile APP/PS1/Tau transgenic mouse model. Sci Rep 2015; 5:15703. [PMID: 26503550 PMCID: PMC4621607 DOI: 10.1038/srep15703] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/28/2015] [Indexed: 01/12/2023] Open
Abstract
The blood-based diagnosis has a potential to provide an alternative approach for easy diagnosis of Alzheimer’s disease (AD) with less invasiveness and low-cost. However, present blood-based AD diagnosis mainly focuses on measuring the plasma Aβ level because no other biomarkers are found to possess evident transport mechanisms to pass the blood-brain barrier. In order to avoid diagnosing non-demented individuals with Aβ abnormality, finding additional biomarkers to supplement plasma Aβ is essential. In this study, we introduce potential neurodegenerative biomarkers for blood-based diagnosis. We observed severe splenomegaly and structural destruction in the spleen with significantly decreased B lymphocytes in senile APPswe, PS1M146V and TauP301L transgenic mice. We also found that inflammatory cytokines associated with splenic dysfunction were altered in the plasma of these mice. These findings suggest potential involvement of the splenic dysfunction in AD and the importance of biomarker level alterations in the plasma as putative diagnostic targets for AD.
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Affiliation(s)
- Seung-Hoon Yang
- Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, Republic of Korea
| | - Jiyoon Kim
- Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, Republic of Korea.,Biological Chemistry Program, Korea University of Science and Technology, 217 Gajungro, Yuseong-gu, Daejeon, Republic of Korea
| | - Michael Jisoo Lee
- Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, Republic of Korea.,Department of Medical Education, California Northstate University College of Medicine, 9700 W Taron Drive, Elk Grove, CA 95757, USA
| | - YoungSoo Kim
- Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul, Republic of Korea.,Biological Chemistry Program, Korea University of Science and Technology, 217 Gajungro, Yuseong-gu, Daejeon, Republic of Korea
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16
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Alldred MJ, Lee SH, Petkova E, Ginsberg SD. Expression profile analysis of vulnerable CA1 pyramidal neurons in young-Middle-Aged Ts65Dn mice. J Comp Neurol 2014; 523:61-74. [PMID: 25131634 DOI: 10.1002/cne.23663] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 08/07/2014] [Accepted: 08/07/2014] [Indexed: 12/19/2022]
Abstract
Down syndrome (DS) is the most prevalent cause of intellectual disability (ID). Individuals with DS show a variety of cognitive deficits, most notably in hippocampal learning and memory, and display pathological hallmarks of Alzheimer's disease (AD), with neurodegeneration of cholinergic basal forebrain (CBF) neurons. Elucidation of the molecular and cellular underpinnings of neuropathology has been assessed via gene expression analysis in a relevant animal model, termed the Ts65Dn mouse. The Ts65Dn mouse is a segmental trisomy model of DS that mimics DS/AD pathology, notably age-related cognitive dysfunction and degeneration of basal forebrain cholinergic neurons (BFCNs). To determine expression level changes, molecular fingerprinting of cornu ammonis 1 (CA1) pyramidal neurons was performed in adult (4-9 month-old) Ts65Dn mice, at the initiation of BFCN degeneration. To quantitate transcriptomic changes during this early time period, laser capture microdissection (LCM), terminal continuation (TC) RNA amplification, custom-designed microarray analysis, and subsequent validation of individual transcripts by qPCR and protein analysis via immunoblotting was performed. The results indicate significant alterations within CA1 pyramidal neurons of Ts65Dn mice compared with normal disomic (2N) littermates, notably in the downregulation of neurotrophins and their cognate neurotrophin receptors among other classes of transcripts relevant to neurodegeneration. The results of this single-population gene expression analysis at the time of septohippocampal deficits in a trisomic mouse model shed light on a vulnerable circuit that may cause the AD-like pathology invariably seen in DS that could help to identify mechanisms of degeneration, and provide novel gene targets for therapeutic interventions. J. Comp. Neurol. 523:61-74, 2015. © 2014 Wiley Periodicals, Inc.
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Affiliation(s)
- Melissa J Alldred
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York, 10962; Department of Psychiatry, New York University Langone Medical Center, New York, New York, 10016
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17
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Glutamatergic transmission aberration: a major cause of behavioral deficits in a murine model of Down's syndrome. J Neurosci 2014; 34:5099-106. [PMID: 24719089 DOI: 10.1523/jneurosci.5338-13.2014] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Trisomy 21, or Down's syndrome (DS), is the most common genetic cause of intellectual disability. Altered neurotransmission in the brains of DS patients leads to hippocampus-dependent learning and memory deficiency. Although genetic mouse models have provided important insights into the genes and mechanisms responsible for DS-specific changes, the molecular mechanisms leading to memory deficits are not clear. We investigated whether the segmental trisomy model of DS, Ts[Rb(12.1716)]2Cje (Ts2), exhibits hippocampal glutamatergic transmission abnormalities and whether these alterations cause behavioral deficits. Behavioral assays demonstrated that Ts2 mice display a deficit in nest building behavior, a measure of hippocampus-dependent nonlearned behavior, as well as dysfunctional hippocampus-dependent spatial memory tested in the object-placement and the Y-maze spontaneous alternation tasks. Magnetic resonance spectra measured in the hippocampi revealed a significantly lower glutamate concentration in Ts2 as compared with normal disomic (2N) littermates. The glutamate deficit accompanied hippocampal NMDA receptor1 (NMDA-R1) mRNA and protein expression level downregulation in Ts2 compared with 2N mice. In concert with these alterations, paired-pulse analyses suggested enhanced synaptic inhibition and/or lack of facilitation in the dentate gyrus of Ts2 compared with 2N mice. Ts2 mice also exhibited disrupted synaptic plasticity in slice recordings of the hippocampal CA1 region. Collectively, these findings imply that deficits in glutamate and NMDA-R1 may be responsible for impairments in synaptic plasticity in the hippocampus associated with behavioral dysfunctions in Ts2 mice. Thus, these findings suggest that glutamatergic deficits have a significant role in causing intellectual disabilities in DS.
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18
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Spencer P, Fry RC, Kisby GE. Unraveling 50-Year-Old Clues Linking Neurodegeneration and Cancer to Cycad Toxins: Are microRNAs Common Mediators? Front Genet 2012; 3:192. [PMID: 23060898 PMCID: PMC3460211 DOI: 10.3389/fgene.2012.00192] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 09/09/2012] [Indexed: 01/19/2023] Open
Abstract
Recognition of overlapping molecular signaling activated by a chemical trigger of cancer and neurodegeneration is new, but the path to this discovery has been long and potholed. Six conferences (1962–1972) examined the puzzling neurotoxic and carcinogenic properties of a then-novel toxin [cycasin: methylazoxymethanol (MAM)-β-d-glucoside] in cycad plants used traditionally for food and medicine on Guam where a complex neurodegenerative disease plagued the indigenous population. Affected families showed combinations of amyotrophic lateral sclerosis (ALS), parkinsonism (P), and/or a dementia (D) akin to Alzheimer’s disease (AD). Modernization saw declining disease rates on Guam and remarkable changes in clinical phenotype (ALS was replaced by P-D and then by D) and in two genetically distinct ALS-PDC-affected populations (Kii-Japan, West Papua-Indonesia) that used cycad seed medicinally. MAM forms DNA lesions – repaired by O6-methylguanine methyltransferase (MGMT) – that perturb mouse brain development and induce malignant tumors in peripheral organs. The brains of young adult MGMT-deficient mice given a single dose of MAM show DNA lesion-linked changes in cell-signaling pathways associated with miRNA-1, which is implicated in colon, liver, and prostate cancers, and in neurological disease, notably AD. MAM is metabolized to formaldehyde, a human carcinogen. Formaldehyde-responsive miRNAs predicted to modulate MAM-associated genes in the brains of MGMT-deficient mice include miR-17-5p and miR-18d, which regulate genes involved in tumor suppression, DNA repair, amyloid deposition, and neurotransmission. These findings marry cycad-associated ALS-PDC with colon, liver, and prostate cancer; they also add to evidence linking changes in microRNA status both to ALS, AD, and parkinsonism, and to cancer initiation and progression.
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Affiliation(s)
- Peter Spencer
- Global Health Center, Oregon Health and Science University Portland, OR, USA
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19
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The use of mouse models for understanding the biology of down syndrome and aging. Curr Gerontol Geriatr Res 2012; 2012:717315. [PMID: 22461792 PMCID: PMC3296169 DOI: 10.1155/2012/717315] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Accepted: 12/06/2011] [Indexed: 12/16/2022] Open
Abstract
Down syndrome is a complex condition caused by trisomy of human chromosome 21. The biology of aging may be different in individuals with Down syndrome; this is not well understood in any organism. Because of its complexity, many aspects of Down syndrome must be studied either in humans or in animal models. Studies in humans are essential but are limited for ethical and practical reasons. Fortunately, genetically altered mice can serve as extremely useful models of Down syndrome, and progress in their production and analysis has been remarkable. Here, we describe various mouse models that have been used to study Down syndrome. We focus on segmental trisomies of mouse chromosome regions syntenic to human chromosome 21, mice in which individual genes have been introduced, or mice in which genes have been silenced by targeted mutagenesis. We selected a limited number of genes for which considerable evidence links them to aspects of Down syndrome, and about which much is known regarding their function. We focused on genes important for brain and cognitive function, and for the altered cancer spectrum seen in individuals with Down syndrome. We conclude with observations on the usefulness of mouse models and speculation on future directions.
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20
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Patterson D, Cabelof DC. Down syndrome as a model of DNA polymerase beta haploinsufficiency and accelerated aging. Mech Ageing Dev 2011; 133:133-7. [PMID: 22019846 DOI: 10.1016/j.mad.2011.10.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 09/20/2011] [Accepted: 10/06/2011] [Indexed: 02/07/2023]
Abstract
Down syndrome is a condition of intellectual disability characterized by accelerated aging. As with other aging syndromes, evidence accumulated over the past several decades points to a DNA repair defect inherent in Down syndrome. This evidence has led us to suggest that Down syndrome results in reduced DNA base excision repair (BER) capacity, and that this contributes to the genomic instability and the aging phenotype of Down syndrome. We propose important roles for microRNA and/or folate metabolism and oxidative stress in the dysregulation of BER in Down syndrome. Further, we suggest these pathways are involved in the leukemogenesis of Down syndrome. We have reviewed the role of BER in the processing of oxidative stress, and the impact of folate depletion on BER capacity. Further, we have reviewed the role that loss of BER, specifically DNA polymerase beta, plays in accelerating the rate of aging. Like that seen in the DNA polymerase beta heterozygous mouse, the aging phenotype of Down syndrome is subtle, unlike the aging phenotypes seen in the classical progeroid syndromes and mouse models of aging. As such, Down syndrome may provide a model for elucidating some of the basic mechanisms of aging.
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Affiliation(s)
- David Patterson
- Eleanor Roosevelt Institute, University of Denver, Denver, CO, USA
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21
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Gómez Ravetti M, Rosso OA, Berretta R, Moscato P. Uncovering molecular biomarkers that correlate cognitive decline with the changes of hippocampus' gene expression profiles in Alzheimer's disease. PLoS One 2010; 5:e10153. [PMID: 20405009 PMCID: PMC2854141 DOI: 10.1371/journal.pone.0010153] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Accepted: 03/22/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is characterized by a neurodegenerative progression that alters cognition. On a phenotypical level, cognition is evaluated by means of the MiniMental State Examination (MMSE) and the post-mortem examination of Neurofibrillary Tangle count (NFT) helps to confirm an AD diagnostic. The MMSE evaluates different aspects of cognition including orientation, short-term memory (retention and recall), attention and language. As there is a normal cognitive decline with aging, and death is the final state on which NFT can be counted, the identification of brain gene expression biomarkers from these phenotypical measures has been elusive. METHODOLOGY/PRINCIPAL FINDINGS We have reanalysed a microarray dataset contributed in 2004 by Blalock et al. of 31 samples corresponding to hippocampus gene expression from 22 AD subjects of varying degree of severity and 9 controls. Instead of only relying on correlations of gene expression with the associated MMSE and NFT measures, and by using modern bioinformatics methods based on information theory and combinatorial optimization, we uncovered a 1,372-probe gene expression signature that presents a high-consensus with established markers of progression in AD. The signature reveals alterations in calcium, insulin, phosphatidylinositol and wnt-signalling. Among the most correlated gene probes with AD severity we found those linked to synaptic function, neurofilament bundle assembly and neuronal plasticity. CONCLUSIONS/SIGNIFICANCE A transcription factors analysis of 1,372-probe signature reveals significant associations with the EGR/KROX family of proteins, MAZ, and E2F1. The gene homologous of EGR1, zif268, Egr-1 or Zenk, together with other members of the EGR family, are consolidating a key role in the neuronal plasticity in the brain. These results indicate a degree of commonality between putative genes involved in AD and prion-induced neurodegenerative processes that warrants further investigation.
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Affiliation(s)
- Martín Gómez Ravetti
- Centre for Bioinformatics, Biomarker Discovery and Information-Based Medicine, The University of Newcastle, Callaghan, New South Wales, Australia
- Hunter Medical Research Institute, Information Based Medicine Program, John Hunter Hospital, New Lambton Heights, New South Wales, Australia
- Australian Research Council Centre of Excellence in Bioinformatics, Callaghan, New South Wales, Australia
| | - Osvaldo A. Rosso
- Centre for Bioinformatics, Biomarker Discovery and Information-Based Medicine, The University of Newcastle, Callaghan, New South Wales, Australia
- Hunter Medical Research Institute, Information Based Medicine Program, John Hunter Hospital, New Lambton Heights, New South Wales, Australia
- Instituto de Cálculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina
| | - Regina Berretta
- Centre for Bioinformatics, Biomarker Discovery and Information-Based Medicine, The University of Newcastle, Callaghan, New South Wales, Australia
- Hunter Medical Research Institute, Information Based Medicine Program, John Hunter Hospital, New Lambton Heights, New South Wales, Australia
| | - Pablo Moscato
- Centre for Bioinformatics, Biomarker Discovery and Information-Based Medicine, The University of Newcastle, Callaghan, New South Wales, Australia
- Hunter Medical Research Institute, Information Based Medicine Program, John Hunter Hospital, New Lambton Heights, New South Wales, Australia
- Australian Research Council Centre of Excellence in Bioinformatics, Callaghan, New South Wales, Australia
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22
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Patterson D. Molecular genetic analysis of Down syndrome. Hum Genet 2009; 126:195-214. [PMID: 19526251 DOI: 10.1007/s00439-009-0696-8] [Citation(s) in RCA: 169] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Accepted: 05/29/2009] [Indexed: 12/18/2022]
Abstract
Down syndrome (DS) is caused by trisomy of all or part of human chromosome 21 (HSA21) and is the most common genetic cause of significant intellectual disability. In addition to intellectual disability, many other health problems, such as congenital heart disease, Alzheimer's disease, leukemia, hypotonia, motor disorders, and various physical anomalies occur at an elevated frequency in people with DS. On the other hand, people with DS seem to be at a decreased risk of certain cancers and perhaps of atherosclerosis. There is wide variability in the phenotypes associated with DS. Although ultimately the phenotypes of DS must be due to trisomy of HSA21, the genetic mechanisms by which the phenotypes arise are not understood. The recent recognition that there are many genetically active elements that do not encode proteins makes the situation more complex. Additional complexity may exist due to possible epigenetic changes that may act differently in DS. Numerous mouse models with features reminiscent of those seen in individuals with DS have been produced and studied in some depth, and these have added considerable insight into possible genetic mechanisms behind some of the phenotypes. These mouse models allow experimental approaches, including attempts at therapy, that are not possible in humans. Progress in understanding the genetic mechanisms by which trisomy of HSA21 leads to DS is the subject of this review.
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Affiliation(s)
- David Patterson
- Eleanor Roosevelt Institute, University of Denver, 2101 E. Wesley Avenue, Denver, CO 80208-6600, USA.
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