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Bruno F, Abondio P, Bruno R, Ceraudo L, Paparazzo E, Citrigno L, Luiselli D, Bruni AC, Passarino G, Colao R, Maletta R, Montesanto A. Alzheimer's disease as a viral disease: Revisiting the infectious hypothesis. Ageing Res Rev 2023; 91:102068. [PMID: 37704050 DOI: 10.1016/j.arr.2023.102068] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 09/05/2023] [Accepted: 09/07/2023] [Indexed: 09/15/2023]
Abstract
Alzheimer's disease (AD) represents the most frequent type of dementia in elderly people. Two major forms of the disease exist: sporadic - the causes of which have not yet been fully understood - and familial - inherited within families from generation to generation, with a clear autosomal dominant transmission of mutations in Presenilin 1 (PSEN1), 2 (PSEN2) or Amyloid Precursors Protein (APP) genes. The main hallmark of AD consists of extracellular deposits of amyloid-beta (Aβ) peptide and intracellular deposits of the hyperphosphorylated form of the tau protein. An ever-growing body of research supports the viral infectious hypothesis of sporadic forms of AD. In particular, it has been shown that several herpes viruses (i.e., HHV-1, HHV-2, HHV-3 or varicella zoster virus, HHV-4 or Epstein Barr virus, HHV-5 or cytomegalovirus, HHV-6A and B, HHV-7), flaviviruses (i.e., Zika virus, Dengue fever virus, Japanese encephalitis virus) as well as Human Immunodeficiency Virus (HIV), hepatitis viruses (HAV, HBV, HCV, HDV, HEV), SARS-CoV2, Ljungan virus (LV), Influenza A virus and Borna disease virus, could increase the risk of AD. Here, we summarized and discussed these results. Based on these findings, significant issues for future studies are also put forward.
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Affiliation(s)
- Francesco Bruno
- Regional Neurogenetic Centre (CRN), Department of Primary Care, Azienda Sanitaria Provinciale Di Catanzaro, Viale A. Perugini, 88046 Lamezia Terme, CZ, Italy; Association for Neurogenetic Research (ARN), Lamezia Terme, CZ, Italy
| | - Paolo Abondio
- Laboratory of Ancient DNA, Department of Cultural Heritage, University of Bologna, Via degli Ariani 1, 48121 Ravenna, Italy.
| | - Rossella Bruno
- Sudent at the Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, 88050 Catanzaro, Italy
| | - Leognano Ceraudo
- Sudent at the Department of Medical and Surgical Sciences, University of Parma, 43121 Parma, Italy
| | - Ersilia Paparazzo
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Rende 87036, Italy
| | - Luigi Citrigno
- National Research Council (CNR) - Institute for Biomedical Research and Innovation - (IRIB), 87050 Mangone, Cosenza, Italy
| | - Donata Luiselli
- Laboratory of Ancient DNA, Department of Cultural Heritage, University of Bologna, Via degli Ariani 1, 48121 Ravenna, Italy
| | - Amalia C Bruni
- Regional Neurogenetic Centre (CRN), Department of Primary Care, Azienda Sanitaria Provinciale Di Catanzaro, Viale A. Perugini, 88046 Lamezia Terme, CZ, Italy; Association for Neurogenetic Research (ARN), Lamezia Terme, CZ, Italy
| | - Giuseppe Passarino
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Rende 87036, Italy
| | - Rosanna Colao
- Regional Neurogenetic Centre (CRN), Department of Primary Care, Azienda Sanitaria Provinciale Di Catanzaro, Viale A. Perugini, 88046 Lamezia Terme, CZ, Italy
| | - Raffaele Maletta
- Regional Neurogenetic Centre (CRN), Department of Primary Care, Azienda Sanitaria Provinciale Di Catanzaro, Viale A. Perugini, 88046 Lamezia Terme, CZ, Italy; Association for Neurogenetic Research (ARN), Lamezia Terme, CZ, Italy
| | - Alberto Montesanto
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Rende 87036, Italy.
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2
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Romanescu C, Schreiner TG, Mukovozov I. The Role of Human Herpesvirus 6 Infection in Alzheimer’s Disease Pathogenicity—A Theoretical Mosaic. J Clin Med 2022; 11:jcm11113061. [PMID: 35683449 PMCID: PMC9181317 DOI: 10.3390/jcm11113061] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/24/2022] [Accepted: 05/27/2022] [Indexed: 02/07/2023] Open
Abstract
Alzheimer’s disease (AD), a neurodegenerative disorder generally affecting older adults, is the most common form of dementia worldwide. The disease is marked by severe cognitive and psychiatric decline and has dramatic personal and social consequences. Considerable time and resources are dedicated to the pursuit of a better understanding of disease mechanisms; however, the ultimate goal of obtaining a viable treatment option remains elusive. Neurodegenerative disease as an outcome of gene–environment interaction is a notion widely accepted today; a clear understanding of how external factors are involved in disease pathogenesis is missing, however. In the case of AD, significant effort has been invested in the study of viral pathogens and their role in disease mechanisms. The current scoping review focuses on the purported role HHV-6 plays in AD pathogenesis. First, early studies demonstrating evidence of HHV-6 cantonment in either post-mortem AD brain specimens or in peripheral blood samples of living AD patients are reviewed. Next, selected examples of possible mechanisms whereby viral infection can directly or indirectly contribute to AD pathogenesis are presented, such as autophagy dysregulation, the interaction between miR155 and HHV-6, and amyloid-beta as an antimicrobial peptide. Finally, closely related topics such as HHV-6 penetration in the CNS, HHV-6 involvement in neuroinflammation, and a brief discussion on HHV-6 epigenetics are examined.
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Affiliation(s)
- Constantin Romanescu
- Clinical Section IV, “St. Parascheva” Infectious Disease Hospital, 700116 Iași, Romania
- Correspondence: (C.R.); (T.G.S.)
| | - Thomas Gabriel Schreiner
- Faculty of Medicine, University of Medicine and Pharmacy “Gr. T. Popa”, 700115 Iasi, Romania
- Faculty of Medicine, University of Medicine and Pharmacy “Carol Davila”, 050474 Bucharest, Romania
- Department of Electrical Measurements and Materials, Faculty of Electrical Engineering and Information Technology, Gheorghe Asachi Technical University of Iasi, 21–23 Professor Dimitrie Mangeron Blvd.,700050 Iasi, Romania
- Correspondence: (C.R.); (T.G.S.)
| | - Ilya Mukovozov
- Department of Dermatology and Skin Science, University of British Columbia, Vancouver, BC V6T 1Z4, Canada;
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3
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Fulop T, Tripathi S, Rodrigues S, Desroches M, Bunt T, Eiser A, Bernier F, Beauregard PB, Barron AE, Khalil A, Plotka A, Hirokawa K, Larbi A, Bocti C, Laurent B, Frost EH, Witkowski JM. Targeting Impaired Antimicrobial Immunity in the Brain for the Treatment of Alzheimer's Disease. Neuropsychiatr Dis Treat 2021; 17:1311-1339. [PMID: 33976546 PMCID: PMC8106529 DOI: 10.2147/ndt.s264910] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/16/2021] [Indexed: 12/12/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia and aging is the most common risk factor for developing the disease. The etiology of AD is not known but AD may be considered as a clinical syndrome with multiple causal pathways contributing to it. The amyloid cascade hypothesis, claiming that excess production or reduced clearance of amyloid-beta (Aβ) and its aggregation into amyloid plaques, was accepted for a long time as the main cause of AD. However, many studies showed that Aβ is a frequent consequence of many challenges/pathologic processes occurring in the brain for decades. A key factor, sustained by experimental data, is that low-grade infection leading to production and deposition of Aβ, which has antimicrobial activity, precedes the development of clinically apparent AD. This infection is chronic, low grade, largely clinically silent for decades because of a nearly efficient antimicrobial immune response in the brain. A chronic inflammatory state is induced that results in neurodegeneration. Interventions that appear to prevent, retard or mitigate the development of AD also appear to modify the disease. In this review, we conceptualize further that the changes in the brain antimicrobial immune response during aging and especially in AD sufferers serve as a foundation that could lead to improved treatment strategies for preventing or decreasing the progression of AD in a disease-modifying treatment.
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Affiliation(s)
- Tamas Fulop
- Research Center on Aging, Geriatric Division, Department of Medicine, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Shreyansh Tripathi
- Cluster Innovation Centre, North Campus, University of Delhi, Delhi, 110007, India.,Ikerbasque, The Basque Foundation for Science, Bilbao, Spain
| | - Serafim Rodrigues
- Ikerbasque, The Basque Foundation for Science, Bilbao, Spain.,Mathematical Computational and Experimental Neuroscience (MCEN), BCAM - The Basque Center for Applied Mathematics, Bilbao, Spain
| | - Mathieu Desroches
- MathNeuro Team, Inria Sophia Antipolis Méditerranée, Sophia Antipolis, France.,Department of Mathematics, Université Côte d'Azur, Nice, France
| | - Ton Bunt
- Izumi Biosciences, Inc., Lexington, MA, USA
| | - Arnold Eiser
- Leonard Davis Institute, University of Pennsylvania, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Francois Bernier
- Morinaga Milk Industry Co., Ltd, Next Generation Science Institute, Kanagawa, Japan
| | - Pascale B Beauregard
- Department of Biology, Faculty of Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Annelise E Barron
- Department of Bioengineering, Stanford School of Medicine, Stanford, CA, USA
| | - Abdelouahed Khalil
- Research Center on Aging, Geriatric Division, Department of Medicine, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Adam Plotka
- Department of Pathophysiology, Medical University of Gdansk, Gdansk, Poland
| | - Katsuiku Hirokawa
- Institute of Health and Life Science, Tokyo Med. Dent. University, Tokyo and Nito-Memory Nakanosogo Hospital, Department of Pathology, Tokyo, Japan
| | - Anis Larbi
- Singapore Immunology Network (SIgN), Agency for Science Technology and Research (ASTAR), Immunos Building, Biopolis, Singapore, Singapore
| | - Christian Bocti
- Research Center on Aging, Department of Medicine, Division of Neurology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Benoit Laurent
- Research Center on Aging, Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Eric H Frost
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Jacek M Witkowski
- Department of Pathophysiology, Medical University of Gdansk, Gdansk, Poland
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Romagnoli M, Porcellini E, Carbone I, Veerhuis R, Licastro F. Impaired Innate Immunity Mechanisms in the Brain of Alzheimer's Disease. Int J Mol Sci 2020; 21:E1126. [PMID: 32046242 PMCID: PMC7038145 DOI: 10.3390/ijms21031126] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/27/2020] [Accepted: 02/05/2020] [Indexed: 12/11/2022] Open
Abstract
Among environmental factors likely associated with Alzheimer's disease (AD), persistent virus infections, and age-related progressive decline of immune competence might play a pivotal role. However, AD antimicrobial brain immune responses are poorly investigated. The present study focused on genes involved in antimicrobial defenses, especially against virus infections, in the AD brain. In particular, mRNA levels of IRF7, MED23, IL28B, and IFN-α genes were analyzed in hippocampus and temporal cortex brain samples from AD and non-demented controls. All subjects were also genotyped for APOE ε, IRF7, MED23, and IL28B gene polymorphisms. Most AD patients showed decreased mRNA levels of all investigated genes in the hippocampus and temporal cortex. However, a small group of AD patients showed increased hippocampal mRNA expression of MED23, IL28B, and IFN-α. mRNA levels of MED23, IL28B, IFN-α from the hippocampus and those of MED23 from the temporal cortex were further decreased in APOE ε4 allele AD carriers. Moreover, rs6598008 polymorphism of IRF7 was significantly associated with decreased hippocampal expression of IRF7, MED23, IL28B, and IFN-α. These findings suggest that AD brains show impaired innate antimicrobial gene expression profiles, and individual genetic makeup, such as positivity for the APOE ε4 and IRF7 A alleles, might affect brain immune efficiency.
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Affiliation(s)
- Martina Romagnoli
- Department of Experimental, Diagnostic and Specialty Medicine, School of Medicine, University of Bologna, Via S. Giacomo 14, 40126 Bologna, Italy; (M.R.); (I.C.); (F.L.)
| | - Elisa Porcellini
- Department of Experimental, Diagnostic and Specialty Medicine, School of Medicine, University of Bologna, Via S. Giacomo 14, 40126 Bologna, Italy; (M.R.); (I.C.); (F.L.)
| | - Ilaria Carbone
- Department of Experimental, Diagnostic and Specialty Medicine, School of Medicine, University of Bologna, Via S. Giacomo 14, 40126 Bologna, Italy; (M.R.); (I.C.); (F.L.)
| | - Robert Veerhuis
- Department of Clinical Chemistry, Vrije Universiteit Amsterdam, Amsterdam UMC, 1105 Amsterdam, The Netherlands;
- Department of Psychiatry, Vrije Universiteit Amsterdam, Amsterdam UMC, 1105 Amsterdam, The Netherlands
| | - Federico Licastro
- Department of Experimental, Diagnostic and Specialty Medicine, School of Medicine, University of Bologna, Via S. Giacomo 14, 40126 Bologna, Italy; (M.R.); (I.C.); (F.L.)
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5
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Talwar P, Gupta R, Kushwaha S, Agarwal R, Saso L, Kukreti S, Kukreti R. Viral Induced Oxidative and Inflammatory Response in Alzheimer's Disease Pathogenesis with Identification of Potential Drug Candidates: A Systematic Review using Systems Biology Approach. Curr Neuropharmacol 2019; 17:352-365. [PMID: 29676229 PMCID: PMC6482477 DOI: 10.2174/1570159x16666180419124508] [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: 10/11/2017] [Revised: 03/19/2018] [Accepted: 04/10/2018] [Indexed: 02/07/2023] Open
Abstract
Alzheimer's disease (AD) is genetically complex with multifactorial etiology. Here, we aim to identify the potential viral pathogens leading to aberrant inflammatory and oxidative stress response in AD along with potential drug candidates using systems biology approach. We retrieved protein interactions of amyloid precursor protein (APP) and tau protein (MAPT) from NCBI and genes for oxidative stress from NetAge, for inflammation from NetAge and InnateDB databases. Genes implicated in aging were retrieved from GenAge database and two GEO expression datasets. These genes were individually used to create protein-protein interaction network using STRING database (score≥0.7). The interactions of candidate genes with known viruses were mapped using virhostnet v2.0 database. Drug molecules targeting candidate genes were retrieved using the Drug- Gene Interaction Database (DGIdb). Data mining resulted in 2095 APP, 116 MAPT, 214 oxidative stress, 1269 inflammatory genes. After STRING PPIN analysis, 404 APP, 109 MAPT, 204 oxidative stress and 1014 inflammation related high confidence proteins were identified. The overlap among all datasets yielded eight common markers (AKT1, GSK3B, APP, APOE, EGFR, PIN1, CASP8 and SNCA). These genes showed association with hepatitis C virus (HCV), Epstein- Barr virus (EBV), human herpes virus 8 and Human papillomavirus (HPV). Further, screening of drugs targeting candidate genes, and possessing anti-inflammatory property, antiviral activity along with a suggested role in AD pathophysiology yielded 12 potential drug candidates. Our study demonstrated the role of viral etiology in AD pathogenesis by elucidating interaction of oxidative stress and inflammation causing candidate genes with common viruses along with the identification of potential AD drug candidates.
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Affiliation(s)
- Puneet Talwar
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Delhi, India
| | - Renu Gupta
- Institute of Human Behaviour & Allied Sciences (IHBAS), Dilshad Garden, Delhi 110 095, India
| | - Suman Kushwaha
- Institute of Human Behaviour & Allied Sciences (IHBAS), Dilshad Garden, Delhi 110 095, India
| | - Rachna Agarwal
- Institute of Human Behaviour & Allied Sciences (IHBAS), Dilshad Garden, Delhi 110 095, India
| | - Luciano Saso
- Department of Physiology and Pharmacology, Sapienza University of Rome, Italy
| | | | - Ritushree Kukreti
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Delhi, India
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6
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Fülöp T, Itzhaki RF, Balin BJ, Miklossy J, Barron AE. Role of Microbes in the Development of Alzheimer's Disease: State of the Art - An International Symposium Presented at the 2017 IAGG Congress in San Francisco. Front Genet 2018; 9:362. [PMID: 30250480 PMCID: PMC6139345 DOI: 10.3389/fgene.2018.00362] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 08/21/2018] [Indexed: 12/17/2022] Open
Abstract
This article reviews research results and ideas presented at a special symposium at the International Association of Gerontology and Geriatrics (IAGG) Congress held in July 2017 in San Francisco. Five researchers presented their results related to infection and Alzheimer's disease (AD). Prof. Itzhaki presented her work on the role of viruses, specifically HSV-1, in the pathogenesis of AD. She maintains that although it is true that most people harbor HSV-1 infection, either latent or active, nonetheless aspects of herpes infection can play a role in the pathogenesis of AD, based on extensive experimental evidence from AD brains and infected cell cultures. Dr. Miklossy presented research on the high prevalence of bacterial infections that correlate with AD, specifically spirochete infections, which have been known for a century to be a significant cause of dementia (e.g., in syphilis). She demonstrated how spirochetes drive senile plaque formation, which are in fact biofilms. Prof. Balin then described the involvement of brain tissue infection by the Chlamydia pneumoniae bacterium, with its potential to use the innate immune system in its spread, and its initiation of tissue damage characteristic of AD. Prof. Fülöp described the role of AD-associated amyloid beta (Aβ) peptide as an antibacterial, antifungal and antiviral innate immune effector produced in reaction to microorganisms that attack the brain. Prof. Barron put forward the novel hypothesis that, according to her experiments, there is strong sequence-specific binding between the AD-associated Aβ and another ubiquitous and important human innate immune effector, the cathelicidin peptide LL-37. Given this binding, LL-37 expression in the brain will decrease Aβ deposition via formation of non-toxic, soluble Aβ/LL-37 complexes. Therefore, a chronic underexpression of LL-37 could be the factor that simultaneously permits chronic infections in brain tissue and allows for pathological accumulation of Aβ. This first-of-its-kind symposium opened the way for a paradigm shift in studying the pathogenesis of AD, from the "amyloid cascade hypothesis," which so far has been quite unsuccessful, to a new "infection hypothesis," or perhaps more broadly, "innate immune system dysregulation hypothesis," which may well permit and lead to the discovery of new treatments for AD patients.
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Affiliation(s)
- Tamàs Fülöp
- Department of Medicine, Division of Geriatrics, Research Center on Aging, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Ruth F. Itzhaki
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Brian J. Balin
- Department of Bio-Medical Sciences, Center for Chronic Disorders of Aging, Philadelphia College of Osteopathic Medicine, Philadelphia, PA, United States
| | - Judith Miklossy
- International Alzheimer Research Centre, Prevention Alzheimer International Foundation, Martigny-Croix, Switzerland
| | - Annelise E. Barron
- Department of Bioengineering, Stanford University, Stanford, CA, United States
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Shao Q, Lin Z, Wu X, Tang J, Lu S, Feng D, Cheng C, Qing L, Yao K, Chen Y. Transcriptome sequencing of neurologic diseases associated genes in HHV-6A infected human astrocyte. Oncotarget 2018; 7:48070-48080. [PMID: 27344170 PMCID: PMC5217001 DOI: 10.18632/oncotarget.10127] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Accepted: 06/01/2016] [Indexed: 01/21/2023] Open
Abstract
Human Herpesvirus 6 (HHV-6) has been involved in the development of several central nervous system (CNS) diseases, such as Alzheimer's disease, multiple sclerosis and glioma. In order to identify the pathogenic mechanism of HHV-6A infection, we carried out mRNA-seq study of human astrocyte HA1800 cell with HHV-6A GS infection. Using mRNA-seq analysis of HA1800-control cells with HA1800-HHV-6A GS cells, we identified 249 differentially expressed genes. After investigating these candidate genes, we found seven genes associated with two or more CNS diseases: CTSS, PTX3, CHI3L1, Mx1, CXCL16, BIRC3, and BST2. This is the first transcriptome sequencing study which showed the significant association of these genes between HHV-6A infection and neurologic diseases. We believe that our findings can provide a new perspective to understand the pathogenic mechanism of HHV-6A infection and neurologic diseases.
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Affiliation(s)
- Qing Shao
- Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu Province, People's Republic of China.,Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, People's Republic of China
| | - Zhe Lin
- Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu Province, People's Republic of China
| | - Xiaohui Wu
- Genetic Data Analysis Group, Shanghai Biotechnology Corporation, Shanghai, People's Republic of China
| | - Junwei Tang
- Liver Transplantation Center of The First Affiliated Hospital and Collaborative Innovation Center For Cancer Personalized Medicine, Nanjing Medical University, Nanjing, Jiangsu Province, People's Republic of China
| | - Shuai Lu
- Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu Province, People's Republic of China
| | - Dongju Feng
- Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu Province, People's Republic of China
| | - Ci Cheng
- Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu Province, People's Republic of China
| | - Lanqun Qing
- Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu Province, People's Republic of China
| | - Kun Yao
- Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu Province, People's Republic of China
| | - Yun Chen
- Department of Immunology, Nanjing Medical University, Nanjing, Jiangsu Province, People's Republic of China
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Itzhaki RF. Herpes and Alzheimer's Disease: Subversion in the Central Nervous System and How It Might Be Halted. J Alzheimers Dis 2018; 54:1273-1281. [PMID: 27497484 DOI: 10.3233/jad-160607] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The last 8 or so years have seen a large increase in the number of studies supporting the concept of a major role for herpes simplex virus type 1 (HSV1) in Alzheimer's disease (AD). The main advances have been made through studies in humans and in mice, investigating the likelihood of reactivation of the latent virus in brain. Others have aimed to explain the mechanisms in cells whereby the increase in amyloid-beta (Aβ) production on HSV1 infection of cells and mouse brains occurs, and the reason that infected cells make this increase. The possibility that other herpesviruses are involved in the development of AD has been explored, and human herpesvirus type 6, Epstein-Barr virus, and cytomegalovirus, in particular, have been implicated. Epidemiological studies have further supported the role specifically of HSV1 and its reactivation in the disease. Antiviral studies have continued, comparing those acting by different mechanisms, such as restricting viral replication, or blocking viral entry into cells, to treat HSV1-infected cell cultures, and then examining the extent to which the virus-induced increases in Aβ and AD-like tau are reduced. All the studies support the usage of antiviral treatment to slow or halt the progression of AD.
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Immune and Imaging Correlates of Mild Cognitive Impairment Conversion to Alzheimer's Disease. Sci Rep 2017; 7:16760. [PMID: 29196629 PMCID: PMC5711836 DOI: 10.1038/s41598-017-16754-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 11/16/2017] [Indexed: 01/18/2023] Open
Abstract
Amnestic mild cognitive impairment (aMCI) conversion to Alzheimer’s disease (AD) is seen in a sizable portion of aMCI patients; correlates predicting such conversion are poorly defined but neuroinflammation and the reactivation of chronic viral infections are suspected to play a role in this phenomenon. We analyzed these aspects in two homogeneous groups of aMCI who did or did not convert to AD over a 24-months period. Results showed that at baseline in those aMCI individuals who did not convert to AD: 1) Aβ1-42 stimulated production of the pro-inflammatory cytokines IL6 and IL1β by CD14+ cells was significantly reduced (p = 0.01), 2) CD14+/IL-33+ cells were increased (p = 0.0004); 3) MFI of TLR8 and TLR9 was significantly increased, and 4) better preserved hippocampus volumes were observed and correlated with IL33+/CD14+ cells. Notably, Aβ1-42 stimulated production of the antiviral cytokine IFN-λ was increased as well in non-AD converters, although with a borderline statistical significance (p = 0.05). Data herein indicating that proinflammatory cytokines are reduced, whereas IFN-λ production and TLR8 and 9 MFI are augmented in those aMCI in whom AD conversion is not observed suggest that the ability to mount stronger antiviral response within an antiiflammatory milieu associates with lack of AD conversion.
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10
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Type-I interferon pathway in neuroinflammation and neurodegeneration: focus on Alzheimer's disease. J Neural Transm (Vienna) 2017; 125:797-807. [PMID: 28676934 DOI: 10.1007/s00702-017-1745-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 06/09/2017] [Indexed: 12/18/2022]
Abstract
Past research in Alzheimer's disease (AD) has largely been driven by the amyloid hypothesis; the accompanying neuroinflammation seen in AD has been assumed to be consequential and not disease modifying or causative. However, recent data from both clinical and preclinical studies have established that the immune-driven neuroinflammation contributes to AD pathology. Key evidence for the involvement of neuroinflammation in AD includes enhanced microglial and astroglial activation in the brains of AD patients, increased pro-inflammatory cytokine burden in AD brains, and epidemiological evidence that chronic non-steroidal anti-inflammatory drug use prior to disease onset leads to a lower incidence of AD. Identifying critical mediators controlling this neuroinflammation will prove beneficial in developing anti-inflammatory therapies for the treatment of AD. The type-I interferons (IFNs) are pleiotropic cytokines that control pro-inflammatory cytokine secretion and are master regulators of the innate immune response that impact on disorders of the central nervous system. This review provides evidence that the type-I IFNs play a critical role in the exacerbation of neuroinflammation and actively contribute to the progression of AD.
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11
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Costa AS, Agostini S, Guerini FR, Mancuso R, Zanzottera M, Ripamonti E, Racca V, Nemni R, Clerici M. Modulation of Immune Responses to Herpes Simplex Virus Type 1 by IFNL3 and IRF7 Polymorphisms: A Study in Alzheimer's Disease. J Alzheimers Dis 2017; 60:1055-1063. [PMID: 28984602 DOI: 10.3233/jad-170520] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Herpes simplex virus type 1 (HSV-1) has long been suspected to play a role in Alzheimer's disease (AD), the most common form of dementia. IFN-lambda (IFN-λ) is one of the key cytokine in innate antiviral defenses and, in particular, has an appreciable antiviral activity against HSV-1 infection. IFN-λ expression is regulated by the interaction between two different proteins: Mediator Complex 23 (MED23) and Interferon-Responsive Transcription Factor 7 (IRF7); single nucleotide polymorphisms (SNPs) in these genes as well as in IFNL3 were shown to be differently distributed in AD patients. In this study, allelic discrimination analysis for IFNL3 rs12979860, MED23 rs3756784, and IRF7 rs6598008, as well as IFN-λ serum concentration and anti-HSV-1 antibody (Ab) titers were performed in 79 AD patients, 57 mild cognitive impairment (MCI) individuals, and 81 healthy controls (HC) who were HSV-1-seropositive. Results showed that INF-λ serum concentration was increased in AD and MCI carrying the IFNL3 T allele compared to HC (AD versus HC: p = 0.014; MCI versus HC: p = 0.029), with the highest anti-HSV-1 Ab titers seen in AD patients carrying the IFNL3 CC genotype (p = 0.012 versus HC). Notably, anti-HSV-1 Ab titers were higher in AD and MCI individuals carrying the IRF7 AA genotype compared to HC (p = 0.018 for both). MED23 polymorphisms did not show any statistical association either with serum IFN-λ or with anti-HSV-1 Ab. Data herein suggest that the IFNL3 rs12979860 and IRF7 rs6598008 polymorphisms modulate immune responses against HSV-1 via their effect on the IFN-λ pathway. These results help to clarify the possible role of HSV-1 infection in AD pathogenesis.
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Affiliation(s)
| | | | | | | | | | | | - Vittorio Racca
- Don Carlo Gnocchi Foundation - ONLUS, IRCCS, Milan, Italy
| | - Raffaello Nemni
- Don Carlo Gnocchi Foundation - ONLUS, IRCCS, Milan, Italy
- Department of Pathophysiology and Transplantation, University of Milano, Milano, Italy
| | - Mario Clerici
- Don Carlo Gnocchi Foundation - ONLUS, IRCCS, Milan, Italy
- Department of Pathophysiology and Transplantation, University of Milano, Milano, Italy
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Agostini S, Mancuso R, Baglio F, Cabinio M, Hernis A, Guerini FR, Calabrese E, Nemni R, Clerici M. Lack of evidence for a role of HHV-6 in the pathogenesis of Alzheimer's disease. J Alzheimers Dis 2016; 49:229-35. [PMID: 26444787 DOI: 10.3233/jad-150464] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND Alzheimer's disease (AD), the most common form of dementia worldwide, is associated with impairment in the mechanisms of the clearing of amyloid-β within a scenario of neuroinflammation. The etiopathogenesis of the AD is unclear, but a role for viral infection is suspected to play a role in initiating the disease. We recently described a positive correlation between high titers of HSV-1-specific antibodies (Ab) and the volumes of brain regions typically affected in disease. OBJECTIVE The exploration of a possible role for Herpesviridae in AD was extended by analyzing HHV-6-specific humoral immunity in individuals with AD or a diagnosis of amnestic mild cognitive impairment (aMCI), a condition that is often prodromic of the development of AD. METHODS 59 AD, 60 aMCI, and 61 age-matched healthy controls were enrolled in the study. Serum HHV-6 IgG antibody titers and avidity index were tested by ELISA. Two randomly selected subgroups of AD and aMCI in whom HHV-6 serum antibodies were detected underwent brain magnetic resonance imaging (MRI) by 1.5 T scanner. RESULTS HHV-6 seroprevalence, antibody titers, and avidity were similar in the three groups. No correlation was found between Ab titers or avidity and brain volumes, either overall or in the regions typically affected by disease. CONCLUSIONS The lack of any relation between humoral immune response against HHV-6 and AD and aMCI seems to rule out a role for this virus in the pathogenesis of AD.
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Affiliation(s)
| | | | | | | | | | | | | | - Raffaello Nemni
- Don C. Gnocchi Foundation - ONLUS, Milan, Italy.,Department of Physiopathology and Transplantation, University of Milan, Italy
| | - Mario Clerici
- Don C. Gnocchi Foundation - ONLUS, Milan, Italy.,Department of Physiopathology and Transplantation, University of Milan, Italy
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