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Chen SH, Damborsky JC, Wilson BC, Fannin RD, Ward JM, Gerrish KE, He B, Martin NP, Yakel JL. α7 Nicotinic Receptor Activation Mitigates Herpes Simplex Virus Type 1 Infection in Microglia Cells. Antiviral Res 2024; 228:105934. [PMID: 38880195 DOI: 10.1016/j.antiviral.2024.105934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 05/20/2024] [Accepted: 06/13/2024] [Indexed: 06/18/2024]
Abstract
Herpes simplex virus type 1 (HSV-1), a neurotropic DNA virus, establishes latency in neural tissues, with reactivation causing severe consequences like encephalitis. Emerging evidence links HSV-1 infection to chronic neuroinflammation and neurodegenerative diseases. Microglia, the central nervous system's (CNS) immune sentinels, express diverse receptors, including α7 nicotinic acetylcholine receptors (α7 nAChRs), critical for immune regulation. Recent studies suggest α7 nAChR activation protects against viral infections. Here, we show that α7 nAChR agonists, choline and PNU-282987, significantly inhibit HSV-1 replication in microglial BV2 cells. Notably, this inhibition is independent of the traditional ionotropic nAChR signaling pathway. mRNA profiling revealed that choline stimulates the expression of antiviral factors, IL-1β and Nos2, and down-regulates the apoptosis genes and type A Lamins in BV2 cells. These findings suggest a novel mechanism by which microglial α7 nAChRs restrict viral infections by regulating innate immune responses.
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Affiliation(s)
- Shih-Heng Chen
- Viral Vector Core Facility, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA; Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Joanne C Damborsky
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Belinda C Wilson
- Viral Vector Core Facility, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA; Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Rick D Fannin
- Molecular Genomics Core Facility, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC USA
| | - James M Ward
- Bioinformatics Support Group, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC USA
| | - Kevin E Gerrish
- Molecular Genomics Core Facility, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC USA
| | - Bo He
- Viral Vector Core Facility, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA; Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Negin P Martin
- Viral Vector Core Facility, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA; Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Jerrel L Yakel
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA.
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2
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Abbate C. The Adult Neurogenesis Theory of Alzheimer's Disease. J Alzheimers Dis 2023:JAD221279. [PMID: 37182879 DOI: 10.3233/jad-221279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Alzheimer's disease starts in neural stem cells (NSCs) in the niches of adult neurogenesis. All primary factors responsible for pathological tau hyperphosphorylation are inherent to adult neurogenesis and migration. However, when amyloid pathology is present, it strongly amplifies tau pathogenesis. Indeed, the progressive accumulation of extracellular amyloid-β deposits in the brain triggers a state of chronic inflammation by microglia. Microglial activation has a significant pro-neurogenic effect that fosters the process of adult neurogenesis and supports neuronal migration. Unfortunately, this "reactive" pro-neurogenic activity ultimately perturbs homeostatic equilibrium in the niches of adult neurogenesis by amplifying tau pathogenesis in AD. This scenario involves NSCs in the subgranular zone of the hippocampal dentate gyrus in late-onset AD (LOAD) and NSCs in the ventricular-subventricular zone along the lateral ventricles in early-onset AD (EOAD), including familial AD (FAD). Neuroblasts carrying the initial seed of tau pathology travel throughout the brain via neuronal migration driven by complex signals and convey the disease from the niches of adult neurogenesis to near (LOAD) or distant (EOAD) brain regions. In these locations, or in close proximity, a focus of degeneration begins to develop. Then, tau pathology spreads from the initial foci to large neuronal networks along neural connections through neuron-to-neuron transmission.
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Affiliation(s)
- Carlo Abbate
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Milan, Italy
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3
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Wainberg M, Luquez T, Koelle DM, Readhead B, Johnston C, Darvas M, Funk CC. The viral hypothesis: how herpesviruses may contribute to Alzheimer's disease. Mol Psychiatry 2021; 26:5476-5480. [PMID: 33972690 PMCID: PMC8758477 DOI: 10.1038/s41380-021-01138-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 04/12/2021] [Accepted: 04/19/2021] [Indexed: 12/14/2022]
Abstract
The hypothesis that infectious agents, particularly herpesviruses, contribute to Alzheimer's disease (AD) pathogenesis has been investigated for decades but has long engendered controversy. In the past 3 years, several studies in mouse models, human tissue models, and population cohorts have reignited interest in this hypothesis. Collectively, these studies suggest that many of the hallmarks of AD, like amyloid beta production and neuroinflammation, can arise as a protective response to acute infection that becomes maladaptive in the case of chronic infection. We place this work in its historical context and explore its etiological implications.
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Affiliation(s)
| | - Tain Luquez
- Institute for Systems Biology, Seattle, WA, USA
| | - David M Koelle
- Department of Medicine, University of Washington, Seattle, WA, USA
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Global Health, University of Washington, Seattle, WA, USA
- Benaroya Research Institute, Seattle, WA, USA
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
| | - Ben Readhead
- Arizona State University-Banner Neurodegenerative Disease Research Center, Arizona State University, Tempe, AZ, USA
| | - Christine Johnston
- Department of Medicine, University of Washington, Seattle, WA, USA
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
| | - Martin Darvas
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
| | - Cory C Funk
- Institute for Systems Biology, Seattle, WA, USA.
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4
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Tyler KL. The Link Between Alzheimer Disease and Herpes Simplex Virus Infection: Better Late Than Never, or Better Never Than Late? Neurotherapeutics 2021; 18:2421-2424. [PMID: 34480291 PMCID: PMC8804014 DOI: 10.1007/s13311-021-01112-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2021] [Indexed: 10/20/2022] Open
Affiliation(s)
- Kenneth L Tyler
- University of Colorado School of Medicine, Neurology Mailstop B182, Research Complex-II, 12700 E. 19th Ave, Aurora, CO, 80045, USA.
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5
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Wu KM, Zhang YR, Huang YY, Dong Q, Tan L, Yu JT. The role of the immune system in Alzheimer's disease. Ageing Res Rev 2021; 70:101409. [PMID: 34273589 DOI: 10.1016/j.arr.2021.101409] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 02/06/2023]
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative disorder where the accumulation of amyloid plaques and the formation of tau tangles are the prominent pathological hallmarks. Increasing preclinical and clinical studies have revealed that different components of the immune system may act as important contributors to AD etiology and pathogenesis. The recognition of misfolded Aβ and tau by immune cells can trigger a series of complex immune responses in AD, and then lead to neuroinflammation and neurodegeneration. In parallel, genome-wide association studies have also identified several immune related loci associated with increased - risk of AD by interfering with the function of immune cells. Other immune related factors, such as impaired immunometabolism, defective meningeal lymphatic vessels and autoimmunity might also be involved in the pathogenesis of AD. Here, we review the data showing the alterations of immune cells in the AD trajectory and seek to demonstrate the crosstalk between the immune cell dysfunction and AD pathology. We then discuss the most relevant research findings in regards to the influences of gene susceptibility of immune cells for AD. We also consider impaired meningeal lymphatics, immunometabolism and autoimmune mechanisms in AD. In addition, immune related biomarkers and immunotherapies for AD are also mentioned in order to offer novel insights for future research.
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6
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Herpes simplex virus, early neuroimaging markers and incidence of Alzheimer's disease. Transl Psychiatry 2021; 11:414. [PMID: 34333531 PMCID: PMC8325675 DOI: 10.1038/s41398-021-01532-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 06/27/2021] [Accepted: 07/12/2021] [Indexed: 02/08/2023] Open
Abstract
While previous studies suggest the implication of herpes simplex virus (HSV) in the onset of Alzheimer's disease (AD), no study has investigated its association with early neuroimaging markers of AD. In the Three-City and the AMI cohorts, the associations between HSV infection and (i) hippocampal volume (n = 349), (ii) white matter alterations in the parahippocampal cingulum and fornix using diffusion tensor imaging (n = 260), and (iii) incidence of AD (n = 1599) were assessed according to APOE4 status. Regardless of APOE4 status, infected subjects presented (i) significantly more microstructural alterations of the parahippocampal cingulum and fornix, (ii) lower hippocampal volumes only when their anti-HSV IgG level was in the highest tercile-reflecting possibly more frequent reactivations of the virus (p = 0.03 for subjects with a high anti-HSV IgG level while there was no association for all infected subjects, p = 0.19), and (iii) had no increased risk of developing AD. Nevertheless, among APOE4 carriers, infected subjects presented lower hippocampal volumes, although not significant (p = 0.09), and a two or three times higher risk of developing AD (adjusted Hazard ratio (aHR) = 2.72 [1.07-6.91] p = 0.04 for infected subjects and aHR = 3.87 [1.45-10.28] p = 0.007 for infected subjects with an anti-HSV IgG level in the highest tercile) while no association was found among APOE4 noncarriers. Our findings support an association between HSV infection and AD and a potential interaction between HSV status and APOE4. This reinforces the need to further investigate the infectious hypothesis of AD, especially the associated susceptibility factors and the possibility of preventive treatments.
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7
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Bacterial Extracellular DNA Promotes β-Amyloid Aggregation. Microorganisms 2021; 9:microorganisms9061301. [PMID: 34203755 PMCID: PMC8232312 DOI: 10.3390/microorganisms9061301] [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] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/05/2021] [Accepted: 06/11/2021] [Indexed: 12/16/2022] Open
Abstract
Alzheimer’s disease is associated with prion-like aggregation of the amyloid β (Aβ) peptide and the subsequent accumulation of misfolded neurotoxic aggregates in the brain. Therefore, it is critical to clearly identify the factors that trigger the cascade of Aβ misfolding and aggregation. Numerous studies have pointed out the association between microorganisms and their virulence factors and Alzheimer’s disease; however, their exact mechanisms of action remain unclear. Recently, we discovered a new pathogenic role of bacterial extracellular DNA, triggering the formation of misfolded Tau aggregates. In this study, we investigated the possible role of DNA extracted from different bacterial and eukaryotic cells in triggering Aβ aggregation in vitro. Interestingly, we found that the extracellular DNA of some, but not all, bacteria is an effective trigger of Aβ aggregation. Furthermore, the acceleration of Aβ nucleation and elongation can vary based on the concentration of the bacterial DNA and the bacterial strain from which this DNA had originated. Our findings suggest that bacterial extracellular DNA might play a previously overlooked role in the Aβ protein misfolding associated with Alzheimer’s disease pathogenesis. Moreover, it highlights a new mechanism of how distantly localized bacteria can remotely contribute to protein misfolding and diseases associated with this process. These findings might lead to the use of bacterial DNA as a novel therapeutic target for the prevention and treatment of Alzheimer’s disease.
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8
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Sait A, Angeli C, Doig AJ, Day PJR. Viral Involvement in Alzheimer's Disease. ACS Chem Neurosci 2021; 12:1049-1060. [PMID: 33687205 PMCID: PMC8033564 DOI: 10.1021/acschemneuro.0c00719] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 02/14/2021] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by the presence of β-amyloid plaques (Aβ) and neurofibrillary tangles (NFTs) in the brain. The prevalence of the disease is increasing and is expected to reach 141 million cases by 2050. Despite the risk factors associated with the disease, there is no known causative agent for AD. Clinical trials with many drugs have failed over the years, and no therapeutic has been approved for AD. There is increasing evidence that pathogens are found in the brains of AD patients and controls, such as human herpes simplex virus-1 (HSV-1). Given the lack of a human model, the route for pathogen entry into the brain remains open for scrutiny and may include entry via a disturbed blood-brain barrier or the olfactory nasal route. Many factors can contribute to the pathogenicity of HSV-1, such as the ability of HSV-1 to remain latent, tau protein phosphorylation, increased accumulation of Aβ invivo and in vitro, and repeated cycle of reactivation if immunocompromised. Intriguingly, valacyclovir, a widely used drug for the treatment of HSV-1 and HSV-2 infection, has shown patient improvement in cognition compared to controls in AD clinical studies. We discuss the potential role of HSV-1 in AD pathogenesis and argue for further studies to investigate this relationship.
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Affiliation(s)
- Ahmad Sait
- Division
of Evolution and Genomic Sciences, Faculty of Biology, Medicine and
Health, The University of Manchester, Manchester M13 9PL, United Kingdom
- Manchester
Institute of Biotechnology, The University
of Manchester, Manchester M1 7DN, United Kingdom
- Faculty
of Applied Medical Science, Medical Laboratory Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Cristian Angeli
- Division
of Evolution and Genomic Sciences, Faculty of Biology, Medicine and
Health, The University of Manchester, Manchester M13 9PL, United Kingdom
- Manchester
Institute of Biotechnology, The University
of Manchester, Manchester M1 7DN, United Kingdom
| | - Andrew J. Doig
- Division
of Neuroscience and Experimental Psychology, School of Biological
Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, United
Kingdom
| | - Philip J. R. Day
- Division
of Evolution and Genomic Sciences, Faculty of Biology, Medicine and
Health, The University of Manchester, Manchester M13 9PL, United Kingdom
- Manchester
Institute of Biotechnology, The University
of Manchester, Manchester M1 7DN, United Kingdom
- Department
of Medicine, University of Cape Town, Cape Town 7925, South Africa
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9
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The association between herpes simplex virus type 1 infection and Alzheimer's disease. J Clin Neurosci 2020; 82:63-70. [PMID: 33317741 DOI: 10.1016/j.jocn.2020.10.044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/19/2020] [Accepted: 10/18/2020] [Indexed: 02/07/2023]
Abstract
There is growing evidence demonstrating the relationship between herpes simplex virus type 1 (HSV-1) infection and Alzheimer's disease (AD). We searched PubMed, Embase, and Cochrane databases for relevant articles. The Newcastle-Ottawa Scale (NOS) was used to evaluate the qualities of these studies. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random-effects models. We also performed subgroup analyses stratified by apolipoprotein ε4 (APOE ε4), NOS score, and the method of confirming AD. A total of 21 studies between 1990 and 2020 were identified. The pooled OR suggested that HSV-1 infection is a risk factor of AD: pooled OR 1.40 (95% CI: 1.13-1.75; I2 = 3%, P = 0.42). In the subgroup analyses, the pooled ORs of HSV-1 infection associated with AD were 0.75 (95% CI: 0.24-2.37) among the APOE ε4-positive individuals; 0.85 (95% CI: 0.61-1.17) among the APOE ε4-negative individuals; 1.51 (95% CI: 1.10-2.06) in the high NOS score studies; 1.23 (95% CI: 0.85-1.76) in the moderate NOS score studies; 1.47 (95% CI: 1.16-1.87) in the clinical diagnosis group, and 1.20 (95% CI: 0.77-1.87) in the autopsy group. Our up-to-date systematic review and meta-analysis suggest that HSV-1 infection is a risk factor of AD.
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10
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Vasefi M, Ghaboolian-Zare E, Abedelwahab H, Osu A. Environmental toxins and Alzheimer's disease progression. Neurochem Int 2020; 141:104852. [PMID: 33010393 DOI: 10.1016/j.neuint.2020.104852] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/05/2020] [Accepted: 09/18/2020] [Indexed: 12/29/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia, which causes progressive memory loss and cognitive decline. Effective strategies to treat or prevent remains one of the most challenging undertakings in the medical field. AD is a complex and multifactorial disease that involves several risk factors. Aging and genetic factors both play important roles in the onset of the AD, however; certain environmental factors have been reported to increase the risk of AD. Chronic exposure to toxins has been seen as an environmental factor that may increase the risk of developing a neurodegenerative disease such as AD. Exposure to metals and biotoxins produced by bacteria, molds, and viruses may contribute to the cognitive decline and pathophysiology associated with AD. Toxins may contribute to the pathology of the disease through various mechanisms such as deposition of amyloid-beta (Aβ) plaques and tangles in the brain, induction of apoptosis, inflammation, or oxidative damage. Here, we will review how toxins affect brain physiology with a focus on mechanisms by which toxins may contribute to the development and progression of AD. A better understanding of these mechanisms may help contribute towards the development of an effective strategy to slow the progression of AD.
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Affiliation(s)
- Maryam Vasefi
- Department Biology, Lamar University, Beaumont, TX, United States.
| | | | | | - Anthony Osu
- Department Biology, Lamar University, Beaumont, TX, United States
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11
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Powell-Doherty RD, Abbott ARN, Nelson LA, Bertke AS. Amyloid-β and p-Tau Anti-Threat Response to Herpes Simplex Virus 1 Infection in Primary Adult Murine Hippocampal Neurons. J Virol 2020; 94:e01874-19. [PMID: 32075924 PMCID: PMC7163132 DOI: 10.1128/jvi.01874-19] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 02/12/2020] [Indexed: 12/18/2022] Open
Abstract
Alzheimer's Disease (AD) is the sixth leading cause of death in the United States. Recent studies have established a potential link between herpes simplex virus 1 (HSV-1) infection and the development of AD. HSV-1 DNA has been detected in AD amyloid plaques in human brains, and treatment with the antiviral acyclovir (ACV) was reported to block the accumulation of the AD-associated proteins beta-amyloid (Aβ) and hyper-phosphorylated tau (p-tau) in Vero and glioblastoma cells. Our goal was to determine whether the accumulation of AD-related proteins is attributable to acute and/or latent HSV-1 infection in mature hippocampal neurons, a region of the brain severely impacted by AD. Primary adult murine hippocampal neuronal cultures infected with HSV-1, with or without antivirals, were assessed for Aβ and p-tau expression over 7 days postinfection. P-tau expression was transiently elevated in HSV-1-infected neurons, as well as in the presence of antivirals alone. Infected neurons, as well as uninfected neurons treated with antivirals, had a greater accumulation of Aβ42 than uninfected untreated neurons. Furthermore, Aβ42 colocalized with HSV-1 latency-associated transcript (LAT) expression. These studies suggest that p-tau potentially acts as an acute response to any perceived danger-associated molecular pattern (DAMP) in primary adult hippocampal neurons, while Aβ aggregation is a long-term response to persistent threats, including HSV-1 infection.IMPORTANCE Growing evidence supports a link between HSV-1 infection and Alzheimer's disease (AD). Although AD is clearly a complex multifactorial disorder, an infectious disease etiology provides alternative therapy opportunities for this devastating disease. Understanding the impact that HSV-1 has on mature neurons and the proteins most strongly associated with AD pathology may identify specific mechanisms that could be manipulated to prevent progression of neurodegeneration and dementia.
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Affiliation(s)
- Rebecca D Powell-Doherty
- Department of Population Health Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia, USA
| | - Amber R N Abbott
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Laura A Nelson
- Department of Population Health Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia, USA
| | - Andrea S Bertke
- Department of Population Health Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia, USA
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12
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Abstract
A hallmark feature of Alzheimer’s disease (AD) and other tauopathies is the misfolding, aggregation and cerebral accumulation of tau deposits. Compelling evidence indicates that misfolded tau aggregates are neurotoxic, producing synaptic loss and neuronal damage. Misfolded tau aggregates are able to spread the pathology from cell-to-cell by a prion like seeding mechanism. The factors implicated in the initiation and progression of tau misfolding and aggregation are largely unclear. In this study, we evaluated the effect of DNA extracted from diverse prokaryotic and eukaryotic cells in tau misfolding and aggregation. Our results show that DNA from various, unrelated gram-positive and gram-negative bacteria results in a more pronounced tau misfolding compared to eukaryotic DNA. Interestingly, a higher effect in promoting tau aggregation was observed for DNA extracted from certain bacterial species previously detected in the brain, CSF or oral cavity of patients with AD. Our findings indicate that microbial DNA may play a previously overlooked role in the propagation of tau protein misfolding and AD pathogenesis, providing a new conceptual framework that positions the compromised blood-brain and intestinal barriers as important sources of microbial DNA in the CNS, opening novel opportunities for therapeutic interventions.
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13
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Warren-Gash C, Forbes HJ, Williamson E, Breuer J, Hayward AC, Mavrodaris A, Ridha BH, Rossor MN, Thomas SL, Smeeth L. Human herpesvirus infections and dementia or mild cognitive impairment: a systematic review and meta-analysis. Sci Rep 2019; 9:4743. [PMID: 30894595 PMCID: PMC6426940 DOI: 10.1038/s41598-019-41218-w] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 03/05/2019] [Indexed: 12/14/2022] Open
Abstract
Interest is growing in the role of infectious agents in the pathogenesis of dementia, but current evidence is limited. We conducted a systematic review and meta-analysis to investigate the effect of any of eight human herpesviruses on development of dementia or mild cognitive impairment (MCI). We searched the Cochrane Library, Embase, Global Health, Medline, PsycINFO, Scopus, Web of Science, clinical trials registers and grey literature sources from inception to December 2017 for observational studies with cohort, case control or self-controlled designs, or randomised controlled trials of interventions against herpesviruses. Pooled effect estimates and 95% confidence intervals (CIs) were generated through random effects meta-analyses across studies with the same design, outcome, and virus type, method and site of measurement. We included 57 studies across various geographic settings. Past infection with herpesviruses, measured by IgG seropositivity, was generally not associated with dementia risk. A single cohort study rated moderate quality showed an association between varicella zoster virus reactivation (ophthalmic zoster) and incident dementia (HR 2.97; 95%CI, 1.89 to 4.66). Recent infection with, or reactivation of, herpes simplex virus type 1 or type 1/2 unspecified, cytomegalovirus and human herpes virus-6 measured by serum IgM, high titre IgG or clinical disease may be associated with dementia or MCI, though results were inconsistent across studies and overall evidence rated very low quality. Longitudinal population studies with robust repeated virus measurements taken sufficiently proximal to dementia onset are needed to establish whether, when and among whom herpesviruses affect dementia risk.
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Affiliation(s)
- Charlotte Warren-Gash
- Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, United Kingdom.
| | - Harriet J Forbes
- Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, United Kingdom
| | - Elizabeth Williamson
- Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, United Kingdom
| | - Judith Breuer
- Division of Infection & Immunity, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Andrew C Hayward
- Institute of Epidemiology and Healthcare, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Angelique Mavrodaris
- Cambridge Institute of Public Health, University of Cambridge, Forvie site, Robinson Way, Cambridge, CB2 0SR, United Kingdom
| | - Basil H Ridha
- NIHR University College London Hospitals Biomedical Research Centre, Maple House, Tottenham Court Road, London, W1T 7DN, United Kingdom
- Dementia Research Centre, Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, United Kingdom
| | - Martin N Rossor
- NIHR University College London Hospitals Biomedical Research Centre, Maple House, Tottenham Court Road, London, W1T 7DN, United Kingdom
- Dementia Research Centre, Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, United Kingdom
| | - Sara L Thomas
- Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, United Kingdom
| | - Liam Smeeth
- Faculty of Epidemiology & Population Health, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, United Kingdom
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14
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Li H, Liu CC, Zheng H, Huang TY. Amyloid, tau, pathogen infection and antimicrobial protection in Alzheimer's disease -conformist, nonconformist, and realistic prospects for AD pathogenesis. Transl Neurodegener 2018; 7:34. [PMID: 30603085 PMCID: PMC6306008 DOI: 10.1186/s40035-018-0139-3] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 12/02/2018] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is a fatal disease that threatens the quality of life of an aging population at a global scale. Various hypotheses on the etiology of AD have been developed over the years to guide efforts in search of therapeutic strategies. MAIN BODY In this review, we focus on four AD hypotheses currently relevant to AD onset: the prevailing amyloid cascade hypothesis, the well-recognized tau hypothesis, the increasingly popular pathogen (viral infection) hypothesis, and the infection-related antimicrobial protection hypothesis. In briefly reviewing the main evidence supporting each hypothesis and discussing the questions that need to be addressed, we hope to gain a better understanding of the complicated multi-layered interactions in potential causal and/or risk factors in AD pathogenesis. As a defining feature of AD, the existence of amyloid deposits is likely fundamental to AD onset but is insufficient to wholly reproduce many complexities of the disorder. A similar belief is currently also applied to hyperphosphorylated tau aggregates within neurons, where tau has been postulated to drive neurodegeneration in the presence of pre-existing Aβ plaques in the brain. Although infection of the central nerve system by pathogens such as viruses may increase AD risk, it is yet to be determined whether this phenomenon is applicable to all cases of sporadic AD and whether it is a primary trigger for AD onset. Lastly, the antimicrobial protection hypothesis provides insight into a potential physiological role for Aβ peptides, but how Aβ/microbial interactions affect AD pathogenesis during aging awaits further validation. Nevertheless, this hypothesis cautions potential adverse effects in Aβ-targeting therapies by hindering potential roles for Aβ in anti-viral protection. CONCLUSION AD is a multi-factor complex disorder, which likely requires a combinatorial therapeutic approach to successfully slow or reduce symptomatic memory decline. A better understanding of how various causal and/or risk factors affecting disease onset and progression will enhance the likelihood of conceiving effective treatment paradigms, which may involve personalized treatment strategies for individual patients at varying stages of disease progression.
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Affiliation(s)
- Hongmei Li
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL USA
| | - Chia-Chen Liu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL USA
| | - Hui Zheng
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX USA
| | - Timothy Y. Huang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, San Diego, CA USA
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15
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Suzich JB, Cliffe AR. Strength in diversity: Understanding the pathways to herpes simplex virus reactivation. Virology 2018; 522:81-91. [PMID: 30014861 DOI: 10.1016/j.virol.2018.07.011] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/05/2018] [Accepted: 07/09/2018] [Indexed: 01/09/2023]
Abstract
Herpes simplex virus (HSV) establishes a latent infection in peripheral neurons and can periodically reactivate to cause disease. Reactivation can be triggered by a variety of stimuli that activate different cellular processes to result in increased HSV lytic gene expression and production of infectious virus. The use of model systems has contributed significantly to our understanding of how reactivation of the virus is triggered by different physiological stimuli that are correlated with recrudescence of human disease. Furthermore, these models have led to the identification of both common and distinct mechanisms of different HSV reactivation pathways. Here, we summarize how the use of these diverse model systems has led to a better understanding of the complexities of HSV reactivation, and we present potential models linking cellular signaling pathways to changes in viral gene expression.
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Affiliation(s)
- Jon B Suzich
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA 22908, United States
| | - Anna R Cliffe
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA 22908, United States.
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16
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Zhang J, Liu H, Wei B. Immune response of T cells during herpes simplex virus type 1 (HSV-1) infection. J Zhejiang Univ Sci B 2017; 18:277-288. [PMID: 28378566 PMCID: PMC5394093 DOI: 10.1631/jzus.b1600460] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 01/07/2017] [Indexed: 12/14/2022]
Abstract
Herpes simplex virus type 1 (HSV-1), a neurotropic member of the alphaherpes virus family, is among the most prevalent and successful human pathogens. HSV-1 can cause serious diseases at every stage of life including fatal disseminated disease in newborns, cold sores, eye disease, and fatal encephalitis in adults. HSV-1 infection can trigger rapid immune responses, and efficient inhibition and clearance of HSV-1 infection rely on both the innate and adaptive immune responses of the host. Multiple strategies have been used to restrict host innate immune responses by HSV-1 to facilitate its infection in host cells. The adaptive immunity of the host plays an important role in inhibiting HSV-1 infections. The activation and regulation of T cells are the important aspects of the adaptive immunity. They play a crucial role in host-mediated immunity and are important for clearing HSV-1. In this review, we examine the findings on T cell immune responses during HSV-1 infection, which hold promise in the design of new vaccine candidates for HSV-1.
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17
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Itzhaki RF, Lathe R, Balin BJ, Ball MJ, Bearer EL, Braak H, Bullido MJ, Carter C, Clerici M, Cosby SL, Del Tredici K, Field H, Fulop T, Grassi C, Griffin WST, Haas J, Hudson AP, Kamer AR, Kell DB, Licastro F, Letenneur L, Lövheim H, Mancuso R, Miklossy J, Otth C, Palamara AT, Perry G, Preston C, Pretorius E, Strandberg T, Tabet N, Taylor-Robinson SD, Whittum-Hudson JA. Microbes and Alzheimer's Disease. J Alzheimers Dis 2016; 51:979-84. [PMID: 26967229 DOI: 10.3233/jad-160152] [Citation(s) in RCA: 354] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Ruth F Itzhaki
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, UK
| | - Richard Lathe
- Division of Infection and Pathway Medicine, University of Edinburgh, Little France, Edinburgh, UK
| | - Brian J Balin
- Center for Chronic Disorders of Aging, Philadelphia College of Osteopathic Medicine, Philadelphia, USA
| | - Melvyn J Ball
- Department of Pathology (Neuropathology), Oregon Health and Science University, Portland, OR, USA
| | - Elaine L Bearer
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Heiko Braak
- Clinical Neuroanatomy Section, Department of Neurology, Center for Biomedical Research, University of Ulm, Ulm, Germany
| | - Maria J Bullido
- Centro de Biologia Molecular 'Severo Ochoa' (CSIC-UAM), Universidad Autonoma de Madrid, and Centro de Investigacion en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | | | - Mario Clerici
- University of Milano and IRCCS SM Nascente, Don C Gnocchi Foundation, Milan, Italy
| | - S Louise Cosby
- Centre for Infection and Immunity, Medical Biology Centre, Queen's University, Belfast, UK
| | - Kelly Del Tredici
- Clinical Neuroanatomy Section, Department of Neurology, Center for Biomedical Research, University of Ulm, Ulm, Germany
| | | | - Tamas Fulop
- Department of Medicine, Division of Geriatrics, Université de Sherbrooke, Sherbrooke, PQ, Canada
| | - Claudio Grassi
- Institute of Human Physiology, Medical School, Universitá Cattolica, Rome; San Raffaele Pisana Scientific Institute for Research, Hospitalization, and Health Care, Rome, Italy
| | - W Sue T Griffin
- Department of Geriatrics, University of Arkansas for Medical Sciences, and Geriatric Research, Education, and Clinical Center, Little Rock, AR, USA
| | - Jürgen Haas
- Division of Infection and Pathway Medicine, University of Edinburgh, Little France, Edinburgh, UK
| | - Alan P Hudson
- Department of Immunology and Microbiology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Angela R Kamer
- NYU College of Dentistry, Department of Periodontology and Implant Dentistry, New York, NY, USA
| | - Douglas B Kell
- School of Chemistry, Manchester Institute of Biotechnology, University of Manchester, Manchester, UK
| | - Federico Licastro
- Department of Experimental, Diagnostic, and Specialty Medicine, School of Medicine, University of Bologna, Bologna, Italy
| | | | - Hugo Lövheim
- Department of Community Medicine and Rehabilitation, Geriatric Medicine, Umeå University, Umeå, Sweden
| | | | - Judith Miklossy
- Prevention Alzheimer International Foundation, International Alzheimer Research Center, Martigny-Croix, Switzerland
| | - Carola Otth
- Institute of Clinical Microbiology, Faculty of Medicine, Austral University of Chile, Valdivia, Chile
| | - Anna Teresa Palamara
- Department of Public Health and Infectious Diseases, Institute Pasteur Cenci Bolognetti Foundation, Sapienza University of Rome; San Raffaele Pisana Scientific Institute for Research, Hospitalization, and Health Care, Rome, Italy
| | - George Perry
- College of Sciences, University of Texas at San Antonio, San Antonio, TX, USA
| | | | - Etheresia Pretorius
- Applied Morphology Research Centre, Department of Physiology, Faculty of Health Sciences, University of Pretoria, Arcadia, South Africa
| | - Timo Strandberg
- Helsinki University Hospital and University of Helsinki; University of Oulu, Centre of Life Course Health Research, Oulu, Finland
| | - Naji Tabet
- Division of Old Age Psychiatry, Brighton and Sussex Medical School, Brighton, UK
| | | | - Judith A Whittum-Hudson
- Departments of Immunology and Microbiology, Internal Medicine (Rheumatology), and Ophthalmology, Wayne State University School of Medicine, Detroit, MI, USA
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18
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Bourgade K, Dupuis G, Frost EH, Fülöp T. Anti-Viral Properties of Amyloid-β Peptides. J Alzheimers Dis 2016; 54:859-878. [DOI: 10.3233/jad-160517] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Karine Bourgade
- Research Center on Aging, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Gilles Dupuis
- Department of Biochemistry, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Eric H. Frost
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Tamàs Fülöp
- Department of Medicine, Research Center on Aging, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada
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19
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Licastro F, Porcellini E. Persistent infections, immune-senescence and Alzheimer's disease. Oncoscience 2016; 3:135-42. [PMID: 27489858 PMCID: PMC4965253 DOI: 10.18632/oncoscience.309] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/15/2016] [Indexed: 12/22/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the most common cause of dementia. Classical hallmarks of AD such as amyloid deposition and neurofibrillary tangles do not completely explain AD pathogenesis. Recent investigations proposed Aβ peptide as an anti-microbial factor. Our previous works suggested that the concomitant presence of single nucleotide polymorphisms (SNPs) from AD genetic studies might impair antiviral defenses and increase the individual susceptibility to herpes virus infection. Viruses of herpes family by inducing frequent cycles of reactivation and latency constantly challenge the immune response and drive the accumulation of memory T cells. However, the immune system is not able to completely eradicate these viruses. The continuous antigen stimulation activates chronic inflammatory responses that may progressively induce neurodegenerative mechanisms in genetically susceptible elderly. The aim of this paper is to suggest new perspectives in clinical pathogenesis of AD with potential prevention and new medical treatment of the age associated cognitive decline.
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Affiliation(s)
- Federico Licastro
- Department of Experimental, Diagnostic and Specialty Medicine, School of Medicine, University of Bologna, Bologna 40126, Italy
| | - Elisa Porcellini
- Department of Experimental, Diagnostic and Specialty Medicine, School of Medicine, University of Bologna, Bologna 40126, Italy
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20
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Bourgade K, Le Page A, Bocti C, Witkowski JM, Dupuis G, Frost EH, Fülöp T. Protective Effect of Amyloid-β Peptides Against Herpes Simplex Virus-1 Infection in a Neuronal Cell Culture Model. J Alzheimers Dis 2016; 50:1227-41. [DOI: 10.3233/jad-150652] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Karine Bourgade
- Research Center on Aging, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
| | - Aurélie Le Page
- Research Center on Aging, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
| | - Christian Bocti
- Department of Medicine, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
| | | | - Gilles Dupuis
- Department of Biochemistry, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
| | - Eric H. Frost
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
| | - Tamás Fülöp
- Department of Medicine, Research Center on Aging, Graduate Program in Immunology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
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21
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Steel AJ, Eslick GD. Herpes Viruses Increase the Risk of Alzheimer’s Disease: A Meta-Analysis. J Alzheimers Dis 2015; 47:351-64. [DOI: 10.3233/jad-140822] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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22
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Herpes simplex infection and the risk of Alzheimer's disease: A nested case-control study. Alzheimers Dement 2015; 11:587-92. [DOI: 10.1016/j.jalz.2014.07.157] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Revised: 05/07/2014] [Accepted: 07/29/2014] [Indexed: 11/24/2022]
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23
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Lövheim H, Gilthorpe J, Adolfsson R, Nilsson LG, Elgh F. Reactivated herpes simplex infection increases the risk of Alzheimer's disease. Alzheimers Dement 2014; 11:593-9. [PMID: 25043910 DOI: 10.1016/j.jalz.2014.04.522] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 03/06/2014] [Accepted: 04/14/2014] [Indexed: 12/14/2022]
Abstract
BACKGROUND Previous studies have suggested a link between herpes simplex virus (HSV) type 1 and the development of Alzheimer's disease (AD). METHODS The present analysis included 3432 persons (53.9% women, mean age at inclusion 62.7 ± 14.4 years) with a mean follow-up time of 11.3 years. The number of incident AD cases was 245. Serum samples were analyzed for anti-HSV antibodies (immunoglobulin (Ig)G and IgM) by enzyme-linked immunosorbent assays. RESULTS The presence of anti-HSV IgG antibodies was not associated with an increased risk for AD, controlled for age and sex (hazard ratio, HR, 0.993, P = .979). However, the presence of anti-HSV IgM at baseline was associated with an increased risk of developing AD (HR 1.959, P = .012). CONCLUSION Positivity for anti-HSV IgM, a sign of reactivated infection, was found to almost double the risk for AD, whereas the presence of anti-HSV IgG antibodies did not affect the risk.
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Affiliation(s)
- Hugo Lövheim
- Department of Community Medicine and Rehabilitation, Geriatric Medicine, Umeå University, Umeå, Sweden.
| | - Jonathan Gilthorpe
- Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden
| | - Rolf Adolfsson
- Department of Clinical Sciences, Psychiatry, Umeå University, Umeå, Sweden
| | - Lars-Göran Nilsson
- Umeå Center for Functional Brain Imaging (UFBI), Umeå University, Umeå, Sweden; Aging Research Center, Karolinska Institutet and Stockholm University, Stockholm, Sweden
| | - Fredrik Elgh
- Department of Clinical Microbiology, Virology, Umeå University, Umeå, Sweden
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24
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Piacentini R, De Chiara G, Li Puma DD, Ripoli C, Marcocci ME, Garaci E, Palamara AT, Grassi C. HSV-1 and Alzheimer's disease: more than a hypothesis. Front Pharmacol 2014; 5:97. [PMID: 24847267 PMCID: PMC4019841 DOI: 10.3389/fphar.2014.00097] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/16/2014] [Indexed: 12/22/2022] Open
Abstract
Among the multiple factors concurring to Alzheimer’s disease (AD) pathogenesis, greater attention should be devoted to the role played by infectious agents. Growing epidemiological and experimental evidence suggests that recurrent herpes simplex virus type-1 (HSV-1) infection is a risk factor for AD although the underlying molecular and functional mechanisms have not been fully elucidated yet. Here, we review literature suggesting the involvement of HSV-1 infection in AD also briefly mentioning possible pharmacological implications of these findings.
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Affiliation(s)
- Roberto Piacentini
- Institute of Human Physiology, Medical School, Università Cattolica del Sacro Cuore Rome, Italy
| | - Giovanna De Chiara
- Institute of Translational Pharmacology, National Research Council Rome, Italy
| | - Domenica D Li Puma
- Institute of Human Physiology, Medical School, Università Cattolica del Sacro Cuore Rome, Italy
| | - Cristian Ripoli
- Institute of Human Physiology, Medical School, Università Cattolica del Sacro Cuore Rome, Italy
| | - Maria E Marcocci
- Department of Public Health and Infectious Diseases, Sapienza University of Rome Rome, Italy
| | - Enrico Garaci
- San Raffaele Pisana Scientific Institute for Research, Hospitalization and Health Care, Telematic University Rome, Italy
| | - Anna T Palamara
- Department of Public Health and Infectious Diseases, Institute Pasteur Cenci Bolognetti Foundation, Sapienza University of Rome Rome, Italy ; San Raffaele Pisana Scientific Institute for Research, Hospitalization and Health Care Rome, Italy
| | - Claudio Grassi
- Institute of Human Physiology, Medical School, Università Cattolica del Sacro Cuore Rome, Italy
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25
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Ball MJ, Lukiw WJ, Kammerman EM, Hill JM. Intracerebral propagation of Alzheimer's disease: strengthening evidence of a herpes simplex virus etiology. Alzheimers Dement 2013; 9:169-75. [PMID: 23159044 PMCID: PMC3578985 DOI: 10.1016/j.jalz.2012.07.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 05/30/2012] [Accepted: 07/15/2012] [Indexed: 01/12/2023]
Abstract
BACKGROUND A faulty human protein, abnormally phosphorylated tau, was recently publicized to spread "like a virus" from neuron to neuron in Alzheimer's patients' brains. For several decades, we have been amassing arguments showing that herpes simplex virus type 1 (HSV-1), not p-tau, propagates this interneuronal, transsynaptic pathologic cascade. METHODS We reiterate convincing data from our own (and other) laboratories, reviewing the first anatomic foothold neurofibrillary tangles gain in brainstem and/or entorhinal cortex; the chronic immunosurveillance cellularity of the trigeminal ganglia wherein HSV-1 awakens from latency to reactivate; the inabilities of p-tau protein's physical properties to promote it to jump synapses; the amino acid homology between human p-tau and VP22, a key target for phosphorylation by HSV serine/threonine-protein kinase UL13; and the exosomic secretion of HSV-1-infected cells' L-particles, attesting to the cell-to-cell passage of microRNAs of herpesviruses. RESULTS The now-maturing construct that reactivated HSV-1 best accounts for the intracerebral propagation of AD changes in the human brain should at last seem highly attractive. This hypothesis might even explain statins' apparent mechanism in some studies for lowering AD incidence. CONCLUSION Provided that funding agencies will quickly ignite a new realm of investigation, the rejuvenated enthusiasm for testing this optimistic construct holds incalculable potential for rapid, efficacious clinical application, through already available and relatively safe antiviral therapeutics.
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Affiliation(s)
- Melvyn J. Ball
- Depts. of Pathology & Neurology, Oregon Health & Science University, Portland
| | - Walter J. Lukiw
- Department of Ophthalmology and Neuroscience Center, Louisiana State University Health Sciences Center, New Orleans, LA.
| | | | - James M. Hill
- Louisiana State University Health Sciences Center, New Orleans, LA.
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26
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Abstract
Late-onset Alzheimer's disease (AD) is the most prevalent cause of dementia among older adults, yet more than a century of research has not determined why this disease develops. One prevailing hypothesis is that late-onset AD is caused by infectious pathogens, an idea widely studied in both humans and experimental animal models. This review examines the infectious AD etiology hypothesis and summarizes existing evidence associating infectious agents with AD in humans. The various mechanisms through which different clinical and subclinical infections could cause or promote the progression of AD are considered, as is the concordance between putative infectious agents and the epidemiology of AD. We searched the PubMed, Web of Science, and EBSCO databases for research articles pertaining to infections and AD and systematically reviewed the evidence linking specific infectious pathogens to AD. The evidence compiled from the literature linking AD to an infectious cause is inconclusive, but the amount of evidence suggestive of an association is too substantial to ignore. Epidemiologic, clinical, and basic science studies that could improve on current understanding of the associations between AD and infections and possibly uncover ways to control this highly prevalent and debilitating disease are suggested.
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Affiliation(s)
| | - Robert Wallace
- Correspondence to Dr. Robert Wallace, Department of Epidemiology, College of Public Health, The University of Iowa, 105 River St. Iowa City, IA 52242 (e-mail: )
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27
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Bearer EL. HSV, axonal transport and Alzheimer's disease: in vitro and in vivo evidence for causal relationships. Future Virol 2012; 7:885-899. [PMID: 23335944 DOI: 10.2217/fvl.12.81] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
HSV, a neurotropic virus, travels within neuronal processes by fast axonal transport. During neuronal infection HSV travels retrograde from the sensory nerve terminus to the neuronal cell body, where it replicates or enters latency. During replication HSV travels anterograde from the cell body to the nerve terminus. Postmortem studies find a high frequency of HSV DNA in the trigeminal ganglia as well as the brain. Studies correlating HSV with Alzheimer's disease (AD) have been controversial. Here we review clinical evidence supporting such a link. Furthermore, the author describes experimental data showing physical interactions between nascent HSV particles and host transport machinery implicated in AD. The author concludes that the complexity of this relationship has been insufficiently explored, although the relative ease and nontoxicity of a potential anti-HSV treatment for AD demands further study.
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Affiliation(s)
- Elaine L Bearer
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 81131, USA
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28
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Yao HW, Ling P, Chen SH, Tung YY, Chen SH. Factors affecting herpes simplex virus reactivation from the explanted mouse brain. Virology 2012; 433:116-23. [PMID: 22884293 DOI: 10.1016/j.virol.2012.07.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2012] [Revised: 07/02/2012] [Accepted: 07/19/2012] [Indexed: 12/19/2022]
Abstract
The majority of encephalitis induced by herpes simplex virus type I (HSV-1) is due to viral reactivation from latency, but few studies have investigated the factors influencing viral reactivation in the brain due to the lack of a sensitive assay. We have established an ex vivo explant assay, which induced efficient viral reactivation in the dissociated mouse brain. Applying this assay, we investigated the infection of four HSV-1 strains with varying degrees of neurovirulence in three mouse strains with different levels of susceptibility to HSV-1 infection. We found that virulent HSV-1 strains and susceptible mouse strains exhibited prolonged viral growth during acute infection, increased latent viral genomes, and efficient explant reactivation in the brain stem. Collectively, both viral neurovirulence and host susceptibility positively correlate with HSV-1 reactivation from the explanted mouse brain.
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Affiliation(s)
- Hui-Wen Yao
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan 701, Republic of China
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29
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Wozniak MA, Itzhaki RF. Antiviral agents in Alzheimer's disease: hope for the future? Ther Adv Neurol Disord 2011; 3:141-52. [PMID: 21179606 DOI: 10.1177/1756285610370069] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
- Matthew A Wozniak
- 3.614 Stopford Building, Faculty of Life Sciences,The University of Manchester,Oxford Road, Manchester M13 9PT, UK
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30
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Wozniak MA, Frost AL, Preston CM, Itzhaki RF. Antivirals reduce the formation of key Alzheimer's disease molecules in cell cultures acutely infected with herpes simplex virus type 1. PLoS One 2011; 6:e25152. [PMID: 22003387 PMCID: PMC3189195 DOI: 10.1371/journal.pone.0025152] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 08/26/2011] [Indexed: 11/18/2022] Open
Abstract
Alzheimer's disease (AD) afflicts around 20 million people worldwide and so there is an urgent need for effective treatment. Our research showing that herpes simplex virus type 1 (HSV1) is a risk factor for AD for the brains of people who possess a specific genetic factor and that the virus causes accumulation of key AD proteins (β-amyloid (Aβ) and abnormally phosphorylated tau (P-tau)), suggests that anti-HSV1 antiviral agents might slow AD progression. However, currently available antiviral agents target HSV1 DNA replication and so might be successful in AD only if Aβ and P-tau accumulation depend on viral DNA replication. Therefore, we investigated firstly the stage(s) of the virus replication cycle required for Aβ and P-tau accumulation, and secondly whether antiviral agents prevent these changes using recombinant strains of HSV1 that progress only partly through the replication cycle and antiviral agents that inhibit HSV1 DNA replication. By quantitative immunocytochemistry we demonstrated that entry, fusion and uncoating of HSV1, are insufficient to induce Aβ and P-tau production. We showed also that none of the "immediate early" viral proteins is directly responsible, and that Aβ and P-tau are produced at a subsequent stage of the HSV1 replication cycle. Importantly, the anti-HSV1 antiviral agents acyclovir, penciclovir and foscarnet reduced Aβ and P-tau accumulation, as well as HSV1, with foscarnet being less effective in each case. P-tau accumulation was found to depend on HSV1 DNA replication, whereas Aβ accumulation was not. The antiviral-induced decrease in Aβ is attributable to the reduced number of new viruses, and hence the reduction in viral spread. Since antiviral agents reduce greatly Aβ and P-tau accumulation in HSV1-infected cells, they would be suitable for treating AD with great advantage unlike current AD therapies, only the virus, not the host cell, would be targeted.
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Affiliation(s)
- Matthew A. Wozniak
- Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom
| | - Alison L. Frost
- Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom
| | - Chris M. Preston
- Centre for Virus Research, Medical Research Council-University of Glasgow, Glasgow, United Kingdom
| | - Ruth F. Itzhaki
- Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom
- * E-mail:
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31
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Abstract
Chronic spirochetal infection can cause slowly progressive dementia, cortical atrophy and amyloid deposition in the atrophic form of general paresis. There is a significant association between Alzheimer disease (AD) and various types of spirochete (including the periodontal pathogen Treponemas and Borrelia burgdorferi), and other pathogens such as Chlamydophyla pneumoniae and herpes simplex virus type-1 (HSV-1). Exposure of mammalian neuronal and glial cells and organotypic cultures to spirochetes reproduces the biological and pathological hallmarks of AD. Senile-plaque-like beta amyloid (Aβ) deposits are also observed in mice following inhalation of C. pneumoniae in vivo, and Aβ accumulation and phosphorylation of tau is induced in neurons by HSV-1 in vitro and in vivo. Specific bacterial ligands, and bacterial and viral DNA and RNA all increase the expression of proinflammatory molecules, which activates the innate and adaptive immune systems. Evasion of pathogens from destruction by the host immune reactions leads to persistent infection, chronic inflammation, neuronal destruction and Aβ deposition. Aβ has been shown to be a pore-forming antimicrobial peptide, indicating that Aβ accumulation might be a response to infection. Global attention and action is needed to support this emerging field of research because dementia might be prevented by combined antibiotic, antiviral and anti-inflammatory therapy.
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32
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Clement C, Bhattacharjee PS, Kumar M, Foster TP, Thompson HW, Hill JM. Upregulation of mouse genes in HSV-1 latent TG after butyrate treatment implicates the multiple roles of the LAT-ICP0 locus. Invest Ophthalmol Vis Sci 2011; 52:1770-9. [PMID: 20881297 DOI: 10.1167/iovs.09-5019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine host response by gene expression in HSV-1 latent trigeminal ganglia (TG) after sodium butyrate (NaBu) treatment. METHODS Corneas of 6-week-old female BALB/c mice were scarified and inoculated with HSV-1 17Syn(+) (high phenotypic reactivator) or its mutant 17ΔPst(LAT(-)) (low phenotypic reactivator) at 10(4) plaque-forming units/eye. NaBu-induced viral reactivation was by intraperitoneal (IP) administration at postinfection (PI) day 28, followed by euthanasia after 1 hour. NaBu-treated, uninfected mice served as the control. The resultant labeled cRNA from TG isolated total RNA was hybridized to gene microarray chips containing 14,000 mouse genes. Quantitative real-time PCR was performed to confirm gene expression. RESULTS Differential induction of gene expression between 17Syn(+) and its mutant 17ΔPst(LAT(-)) was designated as NaBu-induced gene expression and yielded significant upregulation of 2- to 16-fold of 0.4% (56/14,000) host genes probed, comprising mainly nucleosome assembly and binding, central nervous system structural activity, hormonal activity, and signaling activity. Approximately 0.2% (24/14,000) of the host genes, mainly of the same functional categories were downregulated 3- to 11-fold. Immune activity was minor in comparison to our reports on gene expression during latency and heat stress induction. Euchromatin analysis revealed that the LAT-ICP0 locus is amenable to the effects of NaBu. Histone activity was detected by early transcription of histone cluster 2 H2be (Hist2h2be). CONCLUSIONS NaBu-induced reactivation of HSV-1 is twofold: drug action involving significant moderation of specific host epigenetic changes and failure to elicit or suppress immune activity at the early time point of 1 hour.
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Affiliation(s)
- Christian Clement
- Department of Ophthalmology, LSU Eye Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
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Kuhlmann I, Minihane AM, Huebbe P, Nebel A, Rimbach G. Apolipoprotein E genotype and hepatitis C, HIV and herpes simplex disease risk: a literature review. Lipids Health Dis 2010; 9:8. [PMID: 20109174 PMCID: PMC2830997 DOI: 10.1186/1476-511x-9-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Accepted: 01/28/2010] [Indexed: 01/22/2023] Open
Abstract
Apolipoprotein E is a polymorphic and multifunctional protein with numerous roles in lipoprotein metabolism. The three common isoforms apoE2, apoE3 and apoE4 show isoform-specific functional properties including different susceptibilities to diseases. ApoE4 is an accepted risk factor for Alzheimer's disease and cardiovascular disorders. Recently, associations between apoE4 and infectious diseases have been demonstrated. This review summarises how apoE4 may be involved in the infection incidence and associated pathologies of specific infectious diseases, namely hepatitis C, human immunodeficiency virus disease and herpes simplex.ApoE4 seems to be protective against chronic hepatitis C virus infection and retards fibrosis progression. In contrast apoE4 enhances the fusion rate of human immunodeficiency virus with target cell membranes, resulting in accelerated cell entry and faster disease progression. Its association with human immunodeficiency virus-associated dementia remains controversial. Regarding herpes simplex virus infection, apoE4 intensifies virus latency and is associated with increased oxidative damage of the central nervous system, and there is some evidence that herpes simplex virus infection in combination with the apoE4 genotype may be associated with an increased risk of Alzheimer's disease. In addition to reviewing available data from human trials, evidence derived from a variety of cell culture and animal models are considered in this review in order to provide mechanistic insights into observed association between apoE4 genotype and viral disease infection and pathology.
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Affiliation(s)
- Inga Kuhlmann
- Institute of Human Nutrition and Food Science, Christian-Albrechts-University, Hermann-Rodewald-Strasse 6, 24098 Kiel, Germany
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Honjo K, van Reekum R, Verhoeff NPLG. Alzheimer's disease and infection: do infectious agents contribute to progression of Alzheimer's disease? Alzheimers Dement 2009; 5:348-60. [PMID: 19560105 DOI: 10.1016/j.jalz.2008.12.001] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 11/08/2008] [Accepted: 12/04/2008] [Indexed: 12/31/2022]
Abstract
Infection with several important pathogens could constitute risk factors for cognitive impairment, dementia, and Alzheimer's disease (AD) in particular. This review summarizes the data related to infectious agents that appear to have a relationship with AD. Infections with herpes simplex virus type 1, picornavirus, Borna disease virus, Chlamydia pneumoniae, Helicobacter pylori, and spirochete were reported to contribute to the pathophysiology of AD or to cognitive changes. Based on these reports, it may be hypothesized that central nervous system or systemic infections may contribute to the pathogenesis or pathophysiology of AD, and chronic infection with several pathogens should be considered a risk factor for sporadic AD. If this hypothesis holds true, early intervention against infection may delay or even prevent the future development of AD.
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Affiliation(s)
- Kie Honjo
- L.C. Campbell Cognitive Neurology Research Unit, Heart and Stroke Foundation Centre for Stroke Recovery, Section of Neurology, Department of Medicine, Sunnybrook Health Science Centre and University of Toronto, Toronto, Ontario, Canada
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Bhattacharjee PS, Neumann DM, Stark D, Thompson HW, Hill JM. Apolipoprotein E Modulates Establishment of HSV-1 Latency and Survival in a Mouse Ocular Model. Curr Eye Res 2009; 31:703-8. [PMID: 16966142 DOI: 10.1080/02713680600864600] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To evaluate and compare the neuroinvasiveness and neurovirulence after ocular HSV-1 infection in ApoE knockout (ApoE-/-) and control C57BL/6 (ApoE+/+) mice. METHODS Age-matched (14 weeks of age) C57BL/6J (ApoE+/+) female mice and female ApoE knockout (ApoE-/-) mice were inoculated by corneal scarification with HSV-1 strain 17Syn+. Analysis of HSV-1 replication in the mouse cornea was assessed through infectious virus assays of ocular (tear film) swabs at 1 to 5 days postinoculation (PI), slit-lamp examination (SLE) of corneas at PI days 1 to 7, and survival of infected mice. The contribution of apoE to the efficient establishment of latency was measured by real-time PCR quantitation of the latent viral genome in the trigeminal ganglia (TG) of infected mice. RESULTS These studies showed that HSV-1 strain 17Syn+ replicates efficiently in the eyes, regardless of the host ApoE genotype. Neither the scoring of corneal pathology via SLE nor the infectious virus assay of the tear film resulted in any statistical differences between ApoE knockout (-/-) mice or the C57BL/6 (ApoE+/+) mice. In mice latently infected with HSV-1, our real-time PCR data showed significantly lower viral copy numbers of HSV-1 DNA in ApoE knockout (ApoE-/-) mice compared with C57BL/6 (ApoE+/+) mice. C57BL/6 (ApoE+/+) mice are more susceptible to the neurovirulence of HSV-1 strain 17Syn+ than female ApoE knockout (-/-) mice, as demonstrated by the fact that 50% (7/14) of the female C57BL/6 (ApoE+/+) mice inoculated with 17Syn+ died, as opposed to none (0/14) of the age- and sex-matched ApoE knockout mice. CONCLUSIONS These data indicate that age (14 weeks) and sex-matched (female) wild mice with an ApoE null background (ApoE-/-) are more resistant and less efficient in the establishment of latency compared with ApoE+/+ mice in the C57BL/6 background.
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Affiliation(s)
- Partha S Bhattacharjee
- Department of Ophthalmology, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA
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Seropositivity to herpes simplex virus antibodies and risk of Alzheimer's disease: a population-based cohort study. PLoS One 2008; 3:e3637. [PMID: 18982063 PMCID: PMC2572852 DOI: 10.1371/journal.pone.0003637] [Citation(s) in RCA: 168] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Accepted: 10/13/2008] [Indexed: 11/19/2022] Open
Abstract
Background Herpes Simplex Virus (HSV) infection has been proposed as a possible risk factor of Alzheimer's Disease (AD) notably because it is neurotropic, ubiquitous in the general population and able to establish lifelong latency in the host. The fact that HSV was present in elderly subjects with AD suggests that the virus could be a co-factor of the disease. We investigated the risk of developing AD in anti-HSV immunoglobulin G (IgG) positive subjects (indicator of a lifelong infection to HSV) and IgM-positive subjects (indicator of primary infection or reactivation of the virus) in a longitudinal population-based cohort of elderly subjects living in the community. Methods Cox proportional hazard models were used to study the risk of developing AD according to the presence or not of anti-HSV IgG and IgM antibodies, assessed in the sera of 512 elderly initially free of dementia followed for 14 years. Results During the follow-up, 77 incident AD cases were diagnosed. Controlled for age, gender, educational level and Apolipoprotein E4 (APOE4) status, IgM-positive subjects showed a significant higher risk of developing AD (HR = 2.55; 95% CI [1.38–4.72]), although no significant increased risk was observed in IgG-positive subjects (HR = 1.67; 95%CI [0.75–3.73]). No modification effect with APOE4 status was found. Conclusion Reactivation of HSV seropositivity is highly correlated with incident AD. HSV chronic infection may therefore be contributive to the progressive brain damage characteristic of AD.
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Burgos JS, Valdivieso F. Understanding the relationship between ApoE and HSV-1 and its possible significance in Alzheimer’s disease. Future Virol 2007. [DOI: 10.2217/17460794.2.3.239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Evaluation of: Miller RM, Federoff HJ: Isoform-specific effects of ApoE on HSV immediate early gene expression and establishment of latency. Neurobiol. Aging (2006) (Epub ahead of print). It is 100 years since Alzheimer's disease was first described and there is still no consensus of opinion regarding the etiology of its sporadic form. Herpes simplex virus type 1 (HSV-1), in conjunction with apolipoprotein E (ApoE), may well play a role in this form of the disease. In the evaluated article, Miller and Federoff try to determine whether the ApoE profile affects the expression of the HSV-1 immediate-early genes and the production of the virus’ latency-associated transcript. Their results show that overexpression of the intermediate-early genes and the establishment of latency are directly correlated with the ApoE genotype.
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Affiliation(s)
- Javier S Burgos
- NEURON BioPharma, Drug Discovery Unit, Edificio BIC, Avda, Innovación 1, 18100 Armilla, Granada, Spain
| | - Fernando Valdivieso
- Universidad Autónoma de Madrid, Centro de Biología Molecular Severo Ochoa, Departamento de Biologí Molecular Facultad de Ciencias, Lab CX340, 18049 Cantoblanco, Madrid, Spain
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Chen SH, Yao HW, Huang WY, Hsu KS, Lei HY, Shiau AL, Chen SH. Efficient reactivation of latent herpes simplex virus from mouse central nervous system tissues. J Virol 2006; 80:12387-92. [PMID: 17005636 PMCID: PMC1676271 DOI: 10.1128/jvi.01232-06] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For decades, numerous ex vivo studies have documented that latent herpes simplex virus (HSV) reactivates efficiently from ganglia, but rarely from the central nervous systems (CNS), of mice when assayed by mincing tissues before explant culture, despite the presence of viral genomes in both sites. Here we show that 88% of mouse brain stems reactivated latent virus when they were dissociated into cell suspensions before ex vivo explant culture. The efficient reactivation of HSV from the mouse CNS was demonstrated with more than one viral strain, viral serotype, and mouse strain, further indicating that the CNS can be an authentic latency site for HSV with the potential to cause recurrent disease.
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Affiliation(s)
- Shih-Heng Chen
- Department of Microbiology and Immunology, Medical College, National Cheng Kung University, Tainan, Taiwan 701, Republic of China
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Hill JM, Bhattacharjee PS, Neumann DM. Apolipoprotein E alleles can contribute to the pathogenesis of numerous clinical conditions including HSV-1 corneal disease. Exp Eye Res 2006; 84:801-11. [PMID: 17007837 PMCID: PMC2217677 DOI: 10.1016/j.exer.2006.08.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Revised: 07/19/2006] [Accepted: 08/03/2006] [Indexed: 11/18/2022]
Abstract
Apolipoprotein E (ApoE) alleles have been reported to affect the clinical outcome of numerous cardiovascular, neurodegenerative, and viral infectious diseases, including atherosclerosis, Alzheimer's disease (AD), hepatitis C, and HIV. The major alleles of ApoE are 2, 3, and 4. ApoE genotypes have been hypothesized to regulate many biological functions, resulting in significant changes in the onset and/or outcome (severity and duration) of several clinical conditions. Based on genetic analyses in human and animal studies using knockout (ApoE -/-) mice and mice transgenic for human 3 and 4, we present evidence that strongly suggests that the ApoE alleles can regulate the pathogenesis of ocular herpes simplex virus type 1 (HSV-1) infections. This review will summarize the major studies that support this hypothesis. Significant gender based differences in HSV-1 pathogenesis have also been reported, suggesting that hormonal regulation combined with ApoE genotype plays a significant role in HSV-1 pathogenesis. Identification of specific mechanisms in ocular HSV-1 infections related to the ApoE alleles and gender could lead to therapeutic intervention based on the properties of the apoE isoforms. While many clinical investigations have been reported and, to a lesser extent, transgenic mouse studies have been conducted, no specific mechanisms of how ApoE induces or alters clinical disease are known.
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Affiliation(s)
- James M Hill
- Department of Ophthalmology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.
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Hill JM, Gebhardt BM, Azcuy AM, Matthews KE, Lukiw WJ, Steiner I, Thompson HW, Ball MJ. Can a herpes simplex virus type 1 neuroinvasive score be correlated to other risk factors in Alzheimer's disease? Med Hypotheses 2005; 64:320-7. [PMID: 15607565 DOI: 10.1016/j.mehy.2003.11.045] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2003] [Accepted: 11/24/2003] [Indexed: 01/05/2023]
Abstract
Herpes simplex virus type 1 (HSV-1) is latent in the nervous system of most humans. Ball [Can J Neurol Sci 9 (1982) 303] first suggested the hypothesis that HSV-1 could be involved in the pathogenesis of Alzheimer's Disease (AD) by noting that regions of the brain particularly and earliest affected in AD were the same as those most damaged during HSV encephalitis. Data from Itzhaki's research suggests that HSV-1 in the brain and the carriage of an apolipoprotein E allele 4 (ApoE e4) together confer risk for AD [J Pathol 97 (2002) 395], [Mol Chem Neuropathol 28 (1996) 135], [Alzheimer's Rep 1 (1998) 173], [Biochem Soc Trans 26 (1998) 273]. Of the two other studies based on Itzhaki's findings, one showed similar results [Lancet 349 (1997) 1102], and the other showed a similar trend [Lancet 351 (1998) 1330], [Lancet 352 (1998) 1312]. To further examine the role of HSV-1 in the etiology of AD, we have formulated a Neuroinvasive Score that quantifies the presence and viral load of HSV-1 in eight brain regions. These regions are: entorhinal cortex, hippocampus, pons, cerebellum, and neocortex (temporal, parietal, occipital, and frontal). We hypothesize that the Neuroinvasive Score that encompasses the presence, amount, and extent of HSV-1 spreading (neuroinvasiveness), will correlate with the genetic risk factor, ApoE e4, in the assessment of autopsy samples from AD patients. If the neuroinvasive score can be directly correlated to the different stages of AD (mild, moderate, severe), this will strengthen the hypothesis that HSV-1 is involved in AD and that ApoE e4 also confers risk for the development and progression of AD.
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Affiliation(s)
- J M Hill
- Departments of Ophthalmology, Neuroscience, Pharmacology, and Microbiology, LSU Health Sciences Center, New Orleans, LA, USA.
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Hill JM, Steiner I, Matthews KE, Trahan SG, Foster TP, Ball MJ. Statins lower the risk of developing Alzheimer’s disease by limiting lipid raft endocytosis and decreasing the neuronal spread of Herpes simplex virus type 1. Med Hypotheses 2005; 64:53-8. [PMID: 15533611 DOI: 10.1016/j.mehy.2003.12.058] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2003] [Accepted: 12/05/2003] [Indexed: 02/08/2023]
Abstract
Many possible risk factors for Alzheimer's disease (AD) have been investigated, with only a very few showing positive associations and none defining the etiology of the neurodegenerative disease. The presence of herpes simplex virus type 1 (HSV-1) DNA in the brain, coupled with apolipoprotein E allele e4 (ApoE e4), has been suggested to confer an increased risk for AD. Studies have shown that pathogens, including viruses, utilize clathrin-independent endocytosis, i.e., lipid rafts that contain cholesterol, as part of their structure. Moreover, cholesterol-lowering statins have recently been linked with a reduced risk of developing Alzheimer's dementia. We, therefore, posit that long-term statin therapy protects individuals from AD by reducing the neuronal spread of HSV-1 via lipid raft domain pathways. Although the mechanism by which statins reduce AD risk is unknown, they reduce the amount of cholesterol in the plasma membrane and, thus, may decrease the availability of lipid raft pathways to spread HSV-1 within the brain.
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Affiliation(s)
- James M Hill
- Department of Ophthalmology, Louisiana State University Health Sciences Center, New Orleans, LA, USA.
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Itzhaki RF, Wozniak MA, Appelt DM, Balin BJ. Infiltration of the brain by pathogens causes Alzheimer's disease. Neurobiol Aging 2004; 25:619-27. [PMID: 15172740 DOI: 10.1016/j.neurobiolaging.2003.12.021] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2003] [Revised: 12/05/2003] [Accepted: 12/08/2003] [Indexed: 11/19/2022]
Abstract
Despite very numerous studies on Alzheimer's disease (AD), especially on amyloid plaques and neurofibrillary tangles, little information has been obtained thus on the causes of the disease. Evidence is described here that implicates firstly herpes simplex virus type 1 (HSV1) as a strong risk factor when it is present in brain of carriers of the type 4 allele of the gene for apolipoprotein E (APOE-4). Indirect support comes from studies indicating the role of APOE in several diverse diseases of known pathogen cause. A second putative risk factor is the bacterium, Chlamydia pneumoniae. This pathogen has been identified and localized in AD brain. Current studies aimed at "proof of principle" address the entry of the organism into the CNS, the neuroinflammatory response to the organism, and the role that the organism plays in triggering AD pathology. An infection-based animal model demonstrates that following intranasal inoculation of BALB/c mice with C. pneumoniae, amyloid plaques/deposits consistent with those observed in the AD brain develop, thus implicating this infection in the etiology of AD.
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Affiliation(s)
- R F Itzhaki
- Department of Optometry and Neuroscience, University of Manchester Institute of Science and Technology (UMIST), Manchester M60 1QD, UK.
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Mori I, Kimura Y, Naiki H, Matsubara R, Takeuchi T, Yokochi T, Nishiyama Y. Reactivation of HSV-1 in the brain of patients with familial Alzheimer's disease. J Med Virol 2004; 73:605-11. [PMID: 15221907 DOI: 10.1002/jmv.20133] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Herpes simplex virus type 1 (HSV-1) has been proposed as an environmental risk factor for sporadic Alzheimer's disease, although this issue is still in dispute. The involvement of HSV-1 in the pathogenesis of familial Alzheimer's disease, the uncommon type of Alzheimer's disease, has not been addressed yet. We investigated formalin-fixed, paraffin-embedded, postmortem brain tissue sections of three patients with familial Alzheimer's disease for the presence of HSV-1 DNA. The nested polymerase chain reaction (PCR) detected the HSV-1 glycoprotein D gene in the brain of all three patients with familial Alzheimer's disease preferentially in the frontal and temporal cortices, whereas only one case out of six age-matched, non-Alzheimer's disease individuals could disclose the presence of HSV-1 gene. The PCR detected HSV-1 DNA in the frontal cortex of the two patients with sporadic Alzheimer's disease. The presence of HSV-1 was associated with beta-amyloid deposition in the cerebral cortex. To clarify the localization of HSV-1 in the brain tissue of patients with familial Alzheimer's disease, the in situ hybridization of the tyramide signal amplification system was used. It detected the HSV-1-specific signals predominantly in the cytoplasm of cortical neurons in a dot-like staining fashion. In addition, high-sensitivity immunohistochemistry revealed the existence of HSV-1 antigens in the cytoplasm of cortical neurons. This report provides the first evidence of reactivation of HSV-1 in the brain of patients with familial Alzheimer's disease, associated with beta-amyloid deposition, and suggests the possible involvement of HSV-1 together with genetic factors in the pathogenesis of familial Alzheimer's disease.
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Affiliation(s)
- Isamu Mori
- Department of Microbiology and Immunology, Aichi Medical University School of Medicine, Aichi, Japan
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Mori I, Yokochi T, Koide N, Sugiyama T, Yoshida T, Kimura Y, Naiki H, Matsubara R, Takeuchi T, Nishiyama Y. PCR search for the herpes simplex virus type 1 genome in brain sections of patients with familial Alzheimer's disease. J Clin Microbiol 2004; 42:936-7. [PMID: 14766896 PMCID: PMC344502 DOI: 10.1128/jcm.42.2.936-937.2004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Itzhaki RF, Dobson CB, Wozniak MA. Herpes simplex virus type 1 and Alzheimer's disease. Ann Neurol 2004; 55:299-300; author reply 300-1. [PMID: 14755740 DOI: 10.1002/ana.10852] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Burgos JS, Ramirez C, Sastre I, Bullido MJ, Valdivieso F. ApoE4 is more efficient than E3 in brain access by herpes simplex virus type 1. Neuroreport 2003; 14:1825-7. [PMID: 14534428 DOI: 10.1097/00001756-200310060-00013] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Apolipoprotein E (ApoE) plays a relevant role in herpes simplex type 1 (HSV-1) infection of the CNS; after infection by the hematogenous route, the viral neuroinvasiveness directly depends on the APOE gene dose. To analyze the effect of ApoE isoforms on the HSV-1 infectivity to the brain, we have used a model of hematogenous infection of mice humanized for the ApoE3 or the ApoE4 alleles, and we have analyzed the presence of viral DNA in several organs by real time quantitative PCR. We have found that animals expressing human ApoE4 present very high levels of virus in the brain when compared to those expressing the ApoE3 allele; in contrast, there were no significant differences in the viral levels found in peripheral organs. Apolipoprotein E4 seems to facilitate the entry and/or spread of HSV-1 in the brain much more efficiently than E3, pointing to a novel potential mechanism underlying the susceptibility to neurodegenerative processes associated with the ApoE4 allele.
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Affiliation(s)
- Javier S Burgos
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
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Hemling N, Röyttä M, Rinne J, Pöllänen P, Broberg E, Tapio V, Vahlberg T, Hukkanen V. Herpesviruses in brains in Alzheimer's and Parkinson's diseases. Ann Neurol 2003; 54:267-71. [PMID: 12891684 DOI: 10.1002/ana.10662] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We evaluated the association of HSV-1, HHV-6, and VZV with Alzheimer's disease (AD) and Parkinson's disease (PD). Brain specimens for viral DNA polymerase chain reaction represented 34 patients with AD, 40 with PD, and 40 controls. One AD patient (2.9%) was positive for HSV-1 DNA, 88.2% for HHV-6 DNA, and 26.5% for VZV DNA; 17.5% of PD patients were HSV-1 DNA-positive and 75% HHV-6-positive, whereas 40% had VZV DNA. Twenty-five percent of the controls were positive for HSV-1 DNA, 87.5% for HHV-6, and 27.5% for VZV. HSV-1, VZV, or HHV-6 DNA in brains was no additional risk factor for AD.
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Affiliation(s)
- Niina Hemling
- Department of Virology, University of Turku, Turku, Finland
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Affiliation(s)
- Curtis B Dobson
- Molecular Neurobiology Laboratory, Department of Optometry and Neuroscience, UMIST, Manchester M60 1QD, UK
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50
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Esiri MM. Potential for HSV-1 vaccination to reduce risk of HSV-1 encephalitis and/or Alzheimer's disease? Neurobiol Aging 2001; 22:711-3; discussion 717-9. [PMID: 11705628 DOI: 10.1016/s0197-4580(01)00248-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- M M Esiri
- Department of Clinical Neurology, University of Oxford, Oxford Radcliffe NHS Trust, OX2 6HE, Oxford, UK.
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