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Rajendrakumar AL, Arbeev KG, Bagley O, Yashin AI, Ukraintseva S. The association between rs6859 in NECTIN2 gene and Alzheimer's disease is partly mediated by pTau. Front Aging Neurosci 2024; 16:1388363. [PMID: 39165837 PMCID: PMC11334082 DOI: 10.3389/fnagi.2024.1388363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 07/18/2024] [Indexed: 08/22/2024] Open
Abstract
Introduction Emerging evidence suggests a connection between vulnerability to infections and Alzheimer's disease (AD). The nectin cell adhesion molecule 2 (NECTIN2) gene coding for a membrane component of adherens junctions is involved in response to infections, and its single nucleotide polymorphism (SNP) rs6859 was significantly associated with AD risk in several human cohorts. It is unclear, however, how exactly rs6859 influences the development of AD pathology. The aggregation of hyperphosphorylated tau protein (pTau) is a key pathological feature of neurodegeneration in AD, which may be induced by infections, among other factors, and potentially influenced by genes involved in both AD and vulnerability to infections, such as NECTIN2. Materials and methods We conducted a causal mediation analysis (CMA) on a sample of 708 participants in the Alzheimer's disease Neuroimaging Initiative (ADNI). The relationship between rs6859 and Alzheimer's disease (AD), with AD (yes/no) as the outcome and pTau-181 levels in the cerebrospinal fluid (CSF) acting as a mediator in this association, was assessed. Adjusted estimates from the probit and linear regression models were used in the CMA model, where an additive model considered an increase in dosage of the rs6859 A allele (AD risk factor). Results The increase in dose of allele A of the SNP rs6859 resulted in about 0.144 increase per standard deviation (SD) of pTau-181 (95% CI: 0.041, 0.248, p < 0.01). When included together in the probit model, the change in A allele dose and each standard deviation change in pTau-181 predicted 6.84% and 9.79% higher probabilities for AD, respectively. In the CMA, the proportion of the average mediated effect was 17.05% and was higher for the risk allele homozygotes (AA), at 19.40% (95% CI: 6.20%, 43.00%, p < 0.01). The sensitivity analysis confirmed the evidence of a robust mediation effect. Conclusion This study reported a new potential causal relationship between pTau-181 and AD. We found that the association between rs6859 in the NECTIN2 gene and AD is partly mediated by pTau-181 levels in CSF. The rest of this association may be mediated by other factors. Our finding sheds light on the complex interplay between genetic susceptibility, protein aggregation, and neurodegeneration in AD. Further research, using other biomarkers, is needed to uncover the remaining mechanisms of the association between the NECTIN2 gene and AD.
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Affiliation(s)
| | | | | | | | - Svetlana Ukraintseva
- Biodemography of Aging Research Unit, Social Science Research Institute, Duke University, Durham, NC, United States
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Rajendrakumar AL, Arbeev KG, Bagley O, Yashin AI, Ukraintseva S. The association between rs6859 in NECTIN2 gene and Alzheimer's disease is partly mediated by pTau. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.06.21.24309310. [PMID: 38947013 PMCID: PMC11213054 DOI: 10.1101/2024.06.21.24309310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Introduction Emerging evidence suggests a connection between vulnerability to infections and Alzheimer's disease (AD). The nectin cell adhesion molecule 2 (NECTIN2) gene coding for a membrane component of adherens junctions is involved in response to infection, and its single nucleotide polymorphism (SNP) rs6859 was significantly associated with AD risk in several human cohorts. It is unclear, however, how exactly rs6859 influences the development of AD pathology. The aggregation of hyperphosphorylated tau protein (pTau) is a key pathological feature of neurodegeneration in AD, which may be induced by infections, among other factors, and potentially influenced by genes involved in both AD and vulnerability to infections, such as NECTIN2. Materials and methods We conducted a causal mediation analysis (CMA) on a sample of 708 participants in the Alzheimer's Disease Neuroimaging Initiative (ADNI). The relationship between rs6859 and Alzheimer's disease (AD), with AD (yes/no) as the outcome and pTau-181 levels in the cerebrospinal fluid (CSF) acting as a mediator in this association, was assessed. Adjusted estimates from the probit and linear regression models were used in the CMA model, where an additive model considered an increase in dosage of the rs6859 A allele (AD risk factor). Results The increase in dose of allele A of the SNP rs6859 resulted in about 0.144 increase per standard deviation (SD) of pTau-181 (95% CI: 0.041, 0.248, p<0.01). When included together in the probit model, the change in A allele dose and each standard deviation change in pTau-181 predicted 6.84% and 9.79% higher probabilities for AD, respectively. In the CMA, the proportion of the average mediated effect was 17.05% and was higher for the risk allele homozygotes (AA), at 19.40% (95% CI: 6.20%, 43.00%, p<0.01). The sensitivity analysis confirmed the evidence of a robust mediation effect. Conclusion This study reported a new causal relationship between pTau-181 and AD. We found that the association between rs6859 in the NECTIN2 gene and AD is partly mediated by pTau-181 levels in CSF. The rest of this association may be mediated by other factors. Further research, using other biomarkers, is needed to uncover the remaining mechanisms of the association between the NECTIN2 gene and AD.
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Affiliation(s)
| | - Konstantin G. Arbeev
- Biodemography of Aging Research Unit, Duke University, Social Science Research Institute, Durham, NC, USA
| | - Olivia Bagley
- Biodemography of Aging Research Unit, Duke University, Social Science Research Institute, Durham, NC, USA
| | - Anatoliy I. Yashin
- Biodemography of Aging Research Unit, Duke University, Social Science Research Institute, Durham, NC, USA
| | - Svetlana Ukraintseva
- Biodemography of Aging Research Unit, Duke University, Social Science Research Institute, Durham, NC, USA
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Francois AK, Rohani A, Loftus M, Dochnal S, Hrit J, McFarlane S, Whitford A, Lewis A, Krakowiak P, Boutell C, Rothbart SB, Kashatus D, Cliffe AR. Single-genome analysis reveals a heterogeneous association of the herpes simplex virus genome with H3K27me2 and the reader PHF20L1 following infection of human fibroblasts. mBio 2024; 15:e0327823. [PMID: 38411116 PMCID: PMC11005365 DOI: 10.1128/mbio.03278-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 02/05/2024] [Indexed: 02/28/2024] Open
Abstract
The fate of herpesvirus genomes following entry into different cell types is thought to regulate the outcome of infection. For the Herpes simplex virus 1 (HSV-1), latent infection of neurons is characterized by association with repressive heterochromatin marked with Polycomb silencing-associated lysine 27 methylation on histone H3 (H3K27me). However, whether H3K27 methylation plays a role in repressing lytic gene expression in non-neuronal cells is unclear. To address this gap in knowledge, and with consideration that the fate of the viral genome and outcome of HSV-1 infection could be heterogeneous, we developed an assay to quantify the abundance of histone modifications within single viral genome foci of infected fibroblasts. Using this approach, combined with bulk epigenetic techniques, we were unable to detect any role for H3K27me3 during HSV-1 lytic infection of fibroblasts. By contrast, we could detect the lesser studied H3K27me2 on a subpopulation of viral genomes, which was consistent with a role for H3K27 demethylases in promoting lytic gene expression. In addition, viral genomes co-localized with the H3K27me2 reader protein PHF20L1, and this association was enhanced by inhibition of the H3K27 demethylases UTX and JMJD3. Notably, targeting of H3K27me2 to viral genomes was enhanced following infection with a transcriptionally defective virus in the absence of Promyelocytic leukemia nuclear bodies. Collectively, these studies implicate a role for H3K27me2 in fibroblast-associated HSV genome silencing in a manner dependent on genome sub-nuclear localization and transcriptional activity. IMPORTANCE Investigating the potential mechanisms of gene silencing for DNA viruses in different cell types is important to understand the differential outcomes of infection, particularly for viruses like herpesviruses that can undergo distinct types of infection in different cell types. In addition, investigating chromatin association with viral genomes informs on the mechanisms of epigenetic regulation of DNA processes. However, there is a growing appreciation for heterogeneity in the outcome of infection at the single cell, and even single viral genome, level. Here we describe a novel assay for quantifying viral genome foci with chromatin proteins and show that a portion of genomes are targeted for silencing by H3K27me2 and associate with the reader protein PHF20L1. This study raises important questions regarding the mechanism of H3K27me2-specific targeting to viral genomes, the contribution of epigenetic heterogeneity to herpesvirus infection, and the role of PHF20L1 in regulating the outcome of DNA virus infection.
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Affiliation(s)
- Alison K. Francois
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Ali Rohani
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Matt Loftus
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Sara Dochnal
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Joel Hrit
- Department of Epigenetics, Van Andel Institute, Grand Rapids, USA
| | - Steven McFarlane
- MRC - University of Glasgow, Centre for Virus Research, Glasgow, United Kingdom
| | - Abigail Whitford
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Anna Lewis
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Patryk Krakowiak
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Chris Boutell
- MRC - University of Glasgow, Centre for Virus Research, Glasgow, United Kingdom
| | | | - David Kashatus
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Anna R. Cliffe
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
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Williams ZAP, Lang L, Nicolas S, Clarke G, Cryan J, Vauzour D, Nolan YM. Do microbes play a role in Alzheimer's disease? Microb Biotechnol 2024; 17:e14462. [PMID: 38593310 PMCID: PMC11003713 DOI: 10.1111/1751-7915.14462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 03/19/2024] [Indexed: 04/11/2024] Open
Abstract
Alzheimer's disease is a complex and progressive condition that affects essential neurological functions such as memory and reasoning. In the brain, neuronal loss, synaptic dysfunction, proteinopathy, neurofibrillary tangles, and neuroinflammation are the hallmarks of Alzheimer's disease pathophysiology. In addition, recent evidence has highlighted that microbes, whether commensal or pathogenic, also have the ability to interact with their host and to regulate its immune system, therefore participating in the exchanges that lead to peripheral inflammation and neuropathology. Because of this intimate relationship, bacteria, viruses, fungi, and protozoa have been implicated in the development of Alzheimer's disease. Here, we bring together current and most recent evidence of the role of microbes in Alzheimer's disease, raising burning questions that need to be addressed to guide therapeutic approaches and potential prophylactic strategies.
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Affiliation(s)
- Zoë A. P. Williams
- Department of Anatomy and NeuroscienceUniversity College CorkCorkIreland
- APC Microbiome IrelandUniversity College CorkCorkIreland
| | - Leonie Lang
- Norwich Medical School, Faculty of Medicine and Health SciencesUniversity of East AngliaNorwichUK
| | - Sarah Nicolas
- Department of Anatomy and NeuroscienceUniversity College CorkCorkIreland
- APC Microbiome IrelandUniversity College CorkCorkIreland
| | - Gerard Clarke
- APC Microbiome IrelandUniversity College CorkCorkIreland
- Department of Psychiatry and Neurobehavioural ScienceUniversity College CorkCorkIreland
| | - John Cryan
- Department of Anatomy and NeuroscienceUniversity College CorkCorkIreland
- APC Microbiome IrelandUniversity College CorkCorkIreland
| | - David Vauzour
- Norwich Medical School, Faculty of Medicine and Health SciencesUniversity of East AngliaNorwichUK
| | - Yvonne M. Nolan
- Department of Anatomy and NeuroscienceUniversity College CorkCorkIreland
- APC Microbiome IrelandUniversity College CorkCorkIreland
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5
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Wood JA, Chaparala S, Bantang C, Chattopadhyay A, Wesesky MA, Kinchington PR, Nimgaonkar VL, Bloom DC, D'Aiuto L. RNA-Seq time-course analysis of neural precursor cell transcriptome in response to herpes simplex Virus-1 infection. J Neurovirol 2024; 30:131-145. [PMID: 38478163 PMCID: PMC11371869 DOI: 10.1007/s13365-024-01198-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 02/12/2024] [Accepted: 02/20/2024] [Indexed: 09/04/2024]
Abstract
The neurogenic niches within the central nervous system serve as essential reservoirs for neural precursor cells (NPCs), playing a crucial role in neurogenesis. However, these NPCs are particularly vulnerable to infection by the herpes simplex virus 1 (HSV-1). In the present study, we investigated the changes in the transcriptome of NPCs in response to HSV-1 infection using bulk RNA-Seq, compared to those of uninfected samples, at different time points post infection and in the presence or absence of antivirals. The results showed that NPCs upon HSV-1 infection undergo a significant dysregulation of genes playing a crucial role in aspects of neurogenesis, including genes affecting NPC proliferation, migration, and differentiation. Our analysis revealed that the CREB signaling, which plays a crucial role in the regulation of neurogenesis and memory consolidation, was the most consistantly downregulated pathway, even in the presence of antivirals. Additionally, cholesterol biosynthesis was significantly downregulated in HSV-1-infected NPCs. The findings from this study, for the first time, offer insights into the intricate molecular mechanisms that underlie the neurogenesis impairment associated with HSV-1 infection.
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Affiliation(s)
- Joel A Wood
- Western Psychiatric Institute and Clinic, Department of Psychiatry, University of Pittsburgh School of Medicine, 3811 O'Hara Street, 15213, Pittsburgh, PA, USA
| | - Srilakshmi Chaparala
- Molecular Biology Information Service, Health Sciences Library System / Falk Library, University of Pittsburgh, M722 Alan Magee Scaife Hall / 3550 Terrace Street, 15261, Pittsburgh, PA, USA
| | - Cecilia Bantang
- Western Psychiatric Institute and Clinic, Department of Psychiatry, University of Pittsburgh School of Medicine, 3811 O'Hara Street, 15213, Pittsburgh, PA, USA
| | - Ansuman Chattopadhyay
- Molecular Biology Information Service, Health Sciences Library System / Falk Library, University of Pittsburgh, M722 Alan Magee Scaife Hall / 3550 Terrace Street, 15261, Pittsburgh, PA, USA
| | - Maribeth A Wesesky
- Western Psychiatric Institute and Clinic, Department of Psychiatry, University of Pittsburgh School of Medicine, 3811 O'Hara Street, 15213, Pittsburgh, PA, USA
| | - Paul R Kinchington
- Department of Ophthalmology, University of Pittsburgh, Suite 820, Eye & Ear Building, 203 Lothrop Street, 15213, Pittsburgh, PA, USA
| | - Vishwajit L Nimgaonkar
- Western Psychiatric Institute and Clinic, Department of Psychiatry, University of Pittsburgh School of Medicine, 3811 O'Hara Street, 15213, Pittsburgh, PA, USA
- VA Pittsburgh Healthcare system at U.S. Department of Veterans Affairs, Pittsburgh, PA, USA
| | - David C Bloom
- Academic Research Building, Department of Molecular Genetics and Microbiology, University of Florida, 1200 Newell Drive, R2-231, 32610, Gainesville, FL, USA
| | - Leonardo D'Aiuto
- Western Psychiatric Institute and Clinic, Department of Psychiatry, University of Pittsburgh School of Medicine, 3811 O'Hara Street, 15213, Pittsburgh, PA, USA.
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6
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Atarashi N, Morishita M, Matsuda S. Activation of innate immune receptor TLR9 by mitochondrial DNA plays essential roles in the chemical long-term depression of hippocampal neurons. J Biol Chem 2024; 300:105744. [PMID: 38354781 PMCID: PMC10943477 DOI: 10.1016/j.jbc.2024.105744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 01/11/2024] [Accepted: 02/04/2024] [Indexed: 02/16/2024] Open
Abstract
Synaptic plasticity is believed to be the cellular basis for experience-dependent learning and memory. Although long-term depression (LTD), a form of synaptic plasticity, is caused by the activity-dependent reduction of cell surface α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-type glutamate receptors (AMPA receptors) at postsynaptic sites, its regulation by neuronal activity is not completely understood. In this study, we showed that the inhibition of toll-like receptor-9 (TLR9), an innate immune receptor, suppresses N-methyl-d-aspartate (NMDA)-induced reduction of cell surface AMPA receptors in cultured hippocampal neurons. We found that inhibition of TLR9 also blocked NMDA-induced activation of caspase-3, which plays an essential role in the induction of LTD. siRNA-based knockdown of TLR9 also suppressed the NMDA-induced reduction of cell surface AMPA receptors, although the scrambled RNA had no effect on the NMDA-induced trafficking of AMPA receptors. Overexpression of the siRNA-resistant form of TLR9 rescued the AMPA receptor trafficking abolished by siRNA. Furthermore, NMDA stimulation induced rapid mitochondrial morphological changes, mitophagy, and the binding of mitochondrial DNA (mtDNA) to TLR9. Treatment with dideoxycytidine and mitochondrial division inhibitor-1, which block mtDNA replication and mitophagy, respectively, inhibited NMDA-dependent AMPA receptor internalization. These results suggest that mitophagy induced by NMDA receptor activation releases mtDNA and activates TLR9, which plays an essential role in the trafficking of AMPA receptors during the induction of LTD.
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Affiliation(s)
- Naoya Atarashi
- Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo, Japan
| | - Misaki Morishita
- Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo, Japan
| | - Shinji Matsuda
- Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo, Japan; Center for Neuroscience and Biomedical Engineering (CNBE), The University of Electro-Communications, Tokyo, Japan.
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Davidson TL, Stevenson RJ. Vulnerability of the Hippocampus to Insults: Links to Blood-Brain Barrier Dysfunction. Int J Mol Sci 2024; 25:1991. [PMID: 38396670 PMCID: PMC10888241 DOI: 10.3390/ijms25041991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 01/25/2024] [Accepted: 01/29/2024] [Indexed: 02/25/2024] Open
Abstract
The hippocampus is a critical brain substrate for learning and memory; events that harm the hippocampus can seriously impair mental and behavioral functioning. Hippocampal pathophysiologies have been identified as potential causes and effects of a remarkably diverse array of medical diseases, psychological disorders, and environmental sources of damage. It may be that the hippocampus is more vulnerable than other brain areas to insults that are related to these conditions. One purpose of this review is to assess the vulnerability of the hippocampus to the most prevalent types of insults in multiple biomedical domains (i.e., neuroactive pathogens, neurotoxins, neurological conditions, trauma, aging, neurodegenerative disease, acquired brain injury, mental health conditions, endocrine disorders, developmental disabilities, nutrition) and to evaluate whether these insults affect the hippocampus first and more prominently compared to other brain loci. A second purpose is to consider the role of hippocampal blood-brain barrier (BBB) breakdown in either causing or worsening the harmful effects of each insult. Recent research suggests that the hippocampal BBB is more fragile compared to other brain areas and may also be more prone to the disruption of the transport mechanisms that act to maintain the internal milieu. Moreover, a compromised BBB could be a factor that is common to many different types of insults. Our analysis indicates that the hippocampus is more vulnerable to insults compared to other parts of the brain, and that developing interventions that protect the hippocampal BBB may help to prevent or ameliorate the harmful effects of many insults on memory and cognition.
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Affiliation(s)
- Terry L. Davidson
- Department of Neuroscience, Center for Neuroscience and Behavior, American University, 4400 Massachusetts Avenue, NW, Washington, DC 20016, USA
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Gurjar P, Khan AA, Alanazi AM, Vasil'ev VG, Zouganelis G, Alexiou A. Molecular Dissection of Herpes Simplex Virus Type 1 to Elucidate Molecular Mechanisms Behind Latency and Comparison of Its Codon Usage Patterns with Genes Modulated During Alzheimer's Disease as a Part of Host-Pathogen Interaction. J Alzheimers Dis 2024; 97:1111-1123. [PMID: 38306057 DOI: 10.3233/jad-231083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
BACKGROUND Herpes simplex virus type 1 (HSV-1) is associated with Alzheimer's disease, which goes into a cycle of latency and reactivation. The present study was envisaged to understand the reasons for latency and specific molecular patterns present in the HSV-1. OBJECTIVE The objective is the molecular dissection of Herpes simplex virus type 1 to elucidate molecular mechanisms behind latency and compare its codon usage patterns with genes modulated during Alzheimer's disease as a part of host-pathogen interaction. METHODS In the present study, we tried to investigate the potential reasons for the latency of HSV-1 virus bioinformatically by determining the CpG patterns. Also, we investigated the codon usage pattern, the presence of rare codons, codon context, and protein properties. RESULTS The top 222 codon pairs graded based on their frequency in the HSV-1 genome revealed that with only one exception (CUG-UUU), all other codon pairs have codons ending with G/C. Considering it an extension of host-pathogen interaction, we compared HSV-1 codon usage with that of codon usage of genes modulated during Alzheimer's disease, and we found that CGT and TTT are only two codons that exhibited similar codon usage patterns and other codons showed statistically highly significant different codon preferences. Dinucleotide CpG tends to mutate to TpG, suggesting the presence of mutational forces and the imperative role of CpG methylation in HSV-1 latency. CONCLUSIONS Upon comparison of codon usage between HSV-1 and Alzheimer's disease genes, no similarities in codon usage were found as a part of host-pathogen interaction. CpG methylation plays an imperative role in latency HSV-1.
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Affiliation(s)
- Pankaj Gurjar
- Centre for Global Health Research, Saveetha Medical College and Hospital, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, Tamil Nadu, India
- Department of Science and Engineering, Novel Global Community Educational Foundation, Hebersham, Australia
| | - Azmat Ali Khan
- Department of Pharmaceutical Chemistry, Pharmaceutical Biotechnology Laboratory, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Amer M Alanazi
- Department of Pharmaceutical Chemistry, Pharmaceutical Biotechnology Laboratory, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | | | - George Zouganelis
- School of Human Sciences, College of Life and Natural Sciences, University of Derby, Derby, UK
| | - Athanasios Alexiou
- Department of Science and Engineering, Novel Global Community Educational Foundation, Hebersham, Australia
- AFNP Med, Vienna, Austria
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9
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Duchesne S, Rousseau LS, Belzile-Marsolais F, Welch LA, Cournoyer B, Arseneau M, Lapierre V, Poulin SM, Potvin O, Hudon C. A Scoping Review of Alzheimers Disease Hypotheses: An Array of Uni- and Multi-Factorial Theories. J Alzheimers Dis 2024; 99:843-856. [PMID: 38788067 PMCID: PMC11191496 DOI: 10.3233/jad-230772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2024] [Indexed: 05/26/2024]
Abstract
Background There is a common agreement that Alzheimers disease (AD) is inherently complex; otherwise, a general disagreement remains on its etiological underpinning, with numerous alternative hypotheses having been proposed. Objective To perform a scoping review of original manuscripts describing hypotheses and theories of AD published in the past decades. Results We reviewed 131 original manuscripts that fulfilled our inclusion criteria out of more than 13,807 references extracted from open databases. Each entry was characterized as having a single or multifactorial focus and assigned to one of 15 theoretical groupings. Impact was tracked using open citation tools. Results Three stages can be discerned in terms of hypotheses generation, with three quarter of studies proposing a hypothesis characterized as being single-focus. The most important theoretical groupings were the Amyloid group, followed by Metabolism and Mitochondrial dysfunction, then Infections and Cerebrovascular. Lately, evidence towards Genetics and especially Gut/Brain interactions came to the fore. Conclusions When viewed together, these multi-faceted reports reinforce the notion that AD affects multiple sub-cellular, cellular, anatomical, and physiological systems at the same time but at varying degree between individuals. The challenge of providing a comprehensive view of all systems and their interactions remains, alongside ways to manage this inherent complexity.
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Affiliation(s)
- Simon Duchesne
- Department of Radiology and Nuclear Medicine, Université, Laval, Quebec City, QC, Canada
| | - Louis-Simon Rousseau
- CERVO Brain Research Centre, Quebec City, QC, Canada
- School of Psychology, Université, Laval, Quebec City, QC, Canada
| | - Florence Belzile-Marsolais
- CERVO Brain Research Centre, Quebec City, QC, Canada
- School of Psychology, Université, Laval, Quebec City, QC, Canada
| | - Laurie-Ann Welch
- CERVO Brain Research Centre, Quebec City, QC, Canada
- School of Psychology, Université, Laval, Quebec City, QC, Canada
| | | | | | - Véronick Lapierre
- CERVO Brain Research Centre, Quebec City, QC, Canada
- School of Psychology, Université, Laval, Quebec City, QC, Canada
| | | | - Olivier Potvin
- Quebec Heart and Lung Research Institute, Quebec City, QC, Canada
- CERVO Brain Research Centre, Quebec City, QC, Canada
| | - Carol Hudon
- CERVO Brain Research Centre, Quebec City, QC, Canada
- School of Psychology, Université, Laval, Quebec City, QC, Canada
- VITAM Research Centre, Quebec City, QC, Canada
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10
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Francois AK, Rohani A, Loftus M, Dochnal S, Hrit J, McFarlane S, Whitford A, Lewis A, Krakowiak P, Boutell C, Rothbart SB, Kashatus D, Cliffe AR. Single-genome analysis reveals heterogeneous association of the Herpes Simplex Virus genome with H3K27me2 and the reader PHF20L1 following infection of human fibroblasts. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.03.569766. [PMID: 38076966 PMCID: PMC10705572 DOI: 10.1101/2023.12.03.569766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
The fate of herpesvirus genomes following entry into different cell types is thought to regulate the outcome of infection. For the Herpes simplex virus 1 (HSV-1), latent infection of neurons is characterized by association with repressive heterochromatin marked with Polycomb silencing-associated lysine 27 methylation on histone H3 (H3K27me). However, whether H3K27 methylation plays a role in repressing lytic gene expression in non-neuronal cells is unclear. To address this gap in knowledge, and with consideration that the fate of the viral genome and outcome of HSV-1 infection could be heterogeneous, we developed an assay to quantify the abundance of histone modifications within single viral genome foci of infected fibroblasts. Using this approach, combined with bulk epigenetic techniques, we were unable to detect any role for H3K27me3 during HSV-1 lytic infection of fibroblasts. In contrast, we could detect the lesser studied H3K27me2 on a subpopulation of viral genomes, which was consistent with a role for H3K27 demethylases in promoting lytic gene expression. This was consistent with a role for H3K27 demethylases in promoting lytic gene expression. In addition, viral genomes co-localized with the H3K27me2 reader protein PHF20L1, and this association was enhanced by inhibition of the H3K27 demethylases UTX and JMJD3. Notably, targeting of H3K27me2 to viral genomes was enhanced following infection with a transcriptionally defective virus in the absence of Promyelocytic leukemia nuclear bodies. Collectively, these studies implicate a role for H3K27me2 in fibroblast-associated HSV genome silencing in a manner dependent on genome sub-nuclear localization and transcriptional activity.
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Affiliation(s)
- Alison K Francois
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Ali Rohani
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Matt Loftus
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Sara Dochnal
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Joel Hrit
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, 49503
| | - Steven McFarlane
- MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow, Scotland
| | - Abigail Whitford
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Anna Lewis
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Patryk Krakowiak
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Chris Boutell
- MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow, Scotland
| | - Scott B. Rothbart
- Department of Epigenetics, Van Andel Institute, Grand Rapids, MI, 49503
| | - David Kashatus
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
| | - Anna R Cliffe
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, 22908
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11
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Zhou X, Kumar P, Bhuyan DJ, Jensen SO, Roberts TL, Münch GW. Neuroinflammation in Alzheimer's Disease: A Potential Role of Nose-Picking in Pathogen Entry via the Olfactory System? Biomolecules 2023; 13:1568. [PMID: 38002250 PMCID: PMC10669446 DOI: 10.3390/biom13111568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 10/22/2023] [Accepted: 10/23/2023] [Indexed: 11/26/2023] Open
Abstract
Alzheimer's disease (AD) is a complex neurodegenerative disorder characterized by progressive cognitive decline and memory impairment. Many possible factors might contribute to the development of AD, including amyloid peptide and tau deposition, but more recent evidence suggests that neuroinflammation may also play an-at least partial-role in its pathogenesis. In recent years, emerging research has explored the possible involvement of external, invading pathogens in starting or accelerating the neuroinflammatory processes in AD. In this narrative review, we advance the hypothesis that neuroinflammation in AD might be partially caused by viral, bacterial, and fungal pathogens entering the brain through the nose and the olfactory system. The olfactory system represents a plausible route for pathogen entry, given its direct anatomical connection to the brain and its involvement in the early stages of AD. We discuss the potential mechanisms through which pathogens may exploit the olfactory pathway to initiate neuroinflammation, one of them being accidental exposure of the olfactory mucosa to hands contaminated with soil and feces when picking one's nose.
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Affiliation(s)
- Xian Zhou
- NICM Health Research Institute, Western Sydney University, Westmead, NSW 2145, Australia; (X.Z.); (D.J.B.)
| | - Paayal Kumar
- Pharmacology Unit, School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia;
| | - Deep J. Bhuyan
- NICM Health Research Institute, Western Sydney University, Westmead, NSW 2145, Australia; (X.Z.); (D.J.B.)
| | - Slade O. Jensen
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia; (S.O.J.); (T.L.R.)
- Microbiology and Infectious Diseases Unit, School of Medicine, Western Sydney University, Liverpool, NSW 2170, Australia
| | - Tara L. Roberts
- Ingham Institute for Applied Medical Research, Liverpool, NSW 2170, Australia; (S.O.J.); (T.L.R.)
- Oncology Unit, School of Medicine, Western Sydney University, Liverpool, NSW 2170, Australia
| | - Gerald W. Münch
- NICM Health Research Institute, Western Sydney University, Westmead, NSW 2145, Australia; (X.Z.); (D.J.B.)
- Pharmacology Unit, School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia;
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12
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Montenegro YHA, Bobermin LD, Sesterheim P, Salvato RS, Anschau F, de Oliveira MJS, Wyse ATS, Netto CA, Gonçalves CAS, Quincozes-Santos A, Leipnitz G. Serum of COVID-19 patients changes neuroinflammation and mitochondrial homeostasis markers in hippocampus of aged rats. J Neurovirol 2023; 29:577-587. [PMID: 37501054 DOI: 10.1007/s13365-023-01156-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 05/18/2023] [Accepted: 06/26/2023] [Indexed: 07/29/2023]
Abstract
Patients affected by COVID-19 present mostly with respiratory symptoms but acute neurological symptoms are also commonly observed. Furthermore, a considerable number of individuals develop persistent and often remitting symptoms months after infection, characterizing the condition called long-COVID. Since the pathophysiology of acute and persistent neurological manifestations is not fully established, we evaluated the expression of different genes in hippocampal slices of aged rats exposed to the serum of a post-COVID (sPC) individual and to the serum of patients infected by SARS-CoV-2 [Zeta (sZeta) and Gamma (sGamma) variants]. The expression of proteins related to inflammatory process, redox homeostasis, mitochondrial quality control and glial reactivity was determined. Our data show that the exposure to sPC, sZeta and sGamma differentially altered the mRNA levels of most inflammatory proteins and reduced those of antioxidant response markers in rat hippocampus. Furthermore, a decrease in the expression of mitochondrial biogenesis genes was induced by all serum samples, whereas a reduction in mitochondrial dynamics was only caused by sPC. Regarding the glial reactivity, S100B expression was modified by sPC and sZeta. These findings demonstrate that changes in the inflammatory response and a reduction of mitochondrial biogenesis and dynamics may contribute to the neurological damage observed in COVID-19 patients.
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Affiliation(s)
- Yorran Hardman A Montenegro
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Porto Alegre, Brazil.
| | - Larissa Daniele Bobermin
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Porto Alegre, Brazil
| | - Patrícia Sesterheim
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Porto Alegre, Brazil
- Programa de Pós-Graduação em Ciências da Saúde: Cardiologia, Instituto de Cardiologia/ Fundação Universitária de Cardiologia, RS, Porto Alegre, Brazil
- Centro de Desenvolvimento Científico e Tecnológico, Centro Estadual de Vigilância em Saúde da Secretaria de Saúde do Estado do Rio Grande do Sul, RS, Porto Alegre, Brazil
| | - Richard Steiner Salvato
- Centro de Desenvolvimento Científico e Tecnológico, Centro Estadual de Vigilância em Saúde da Secretaria de Saúde do Estado do Rio Grande do Sul, RS, Porto Alegre, Brazil
| | - Fernando Anschau
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Porto Alegre, Brazil
- Setor de Pesquisa da Gerência de Ensino, Pesquisa e Inovação do Grupo Hospitalar Conceição (GHC), RS, Porto Alegre, Brazil
- Programa de Pós-Graduação em Avaliação de Tecnologias para o SUS do GHC, Porto Alegre, RS, Brazil
- Escola de Medicina, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Maria José Santos de Oliveira
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Porto Alegre, Brazil
| | - Angela T S Wyse
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Porto Alegre, Brazil
| | - Carlos Alexandre Netto
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Porto Alegre, Brazil
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Porto Alegre, Brazil
| | - Carlos-Alberto Saraiva Gonçalves
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Porto Alegre, Brazil
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Porto Alegre, Brazil
| | - André Quincozes-Santos
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Porto Alegre, Brazil
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Porto Alegre, Brazil
| | - Guilhian Leipnitz
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Porto Alegre, Brazil.
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Porto Alegre, Brazil.
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13
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Piotrowski SL, Tucker A, Jacobson S. The elusive role of herpesviruses in Alzheimer's disease: current evidence and future directions. NEUROIMMUNE PHARMACOLOGY AND THERAPEUTICS 2023; 2:253-266. [PMID: 38013835 PMCID: PMC10474380 DOI: 10.1515/nipt-2023-0011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 06/26/2023] [Indexed: 11/29/2023]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia. While pathologic hallmarks, such as extracellular beta-amyloid plaques, are well-characterized in affected individuals, the pathogenesis that causes plaque formation and eventual cognitive decline is not well understood. A recent resurgence of the decades-old "infectious hypothesis" has garnered increased attention on the potential role that microbes may play in AD. In this theory, it is thought that pathogens such as viruses may act as seeds for beta-amyloid aggregation, ultimately leading to plaques. Interest in the infectious hypothesis has also spurred further investigation into additional characteristics of viral infection that may play a role in AD progression, such as neuroinflammation, latency, and viral DNA integration. While a flurry of research in this area has been recently published, with herpesviruses being of particular interest, the role of pathogens in AD remains controversial. In this review, the insights gained thus far into the possible role of herpesviruses in AD are summarized. The challenges and potential future directions of herpesvirus research in AD and dementia are also discussed.
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Affiliation(s)
- Stacey L. Piotrowski
- Viral Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
- Comparative Biomedical Scientist Training Program, National Institutes of Health, Bethesda, MD, USA
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA
| | - Allison Tucker
- Viral Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Steven Jacobson
- Viral Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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14
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Granholm AC. Long-Term Effects of SARS-CoV-2 in the Brain: Clinical Consequences and Molecular Mechanisms. J Clin Med 2023; 12:3190. [PMID: 37176630 PMCID: PMC10179128 DOI: 10.3390/jcm12093190] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 04/06/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
Numerous investigations have demonstrated significant and long-lasting neurological manifestations of COVID-19. It has been suggested that as many as four out of five patients who sustained COVID-19 will show one or several neurological symptoms that can last months after the infection has run its course. Neurological symptoms are most common in people who are less than 60 years of age, while encephalopathy is more common in those over 60. Biological mechanisms for these neurological symptoms need to be investigated and may include both direct and indirect effects of the virus on the brain and spinal cord. Individuals with Alzheimer's disease (AD) and related dementia, as well as persons with Down syndrome (DS), are especially vulnerable to COVID-19, but the biological reasons for this are not clear. Investigating the neurological consequences of COVID-19 is an urgent emerging medical need, since close to 700 million people worldwide have now had COVID-19 at least once. It is likely that there will be a new burden on healthcare and the economy dealing with the long-term neurological consequences of severe SARS-CoV-2 infections and long COVID, even in younger generations. Interestingly, neurological symptoms after an acute infection are strikingly similar to the symptoms observed after a mild traumatic brain injury (mTBI) or concussion, including dizziness, balance issues, anosmia, and headaches. The possible convergence of biological pathways involved in both will be discussed. The current review is focused on the most commonly described neurological symptoms, as well as the possible molecular mechanisms involved.
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Affiliation(s)
- Ann-Charlotte Granholm
- Department of Neurosurgery, University of Colorado Anschutz Medical Campus, Denver, CO 80045-0511, USA
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15
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Hernandez-Ruiz V, Letenneur L, Fülöp T, Helmer C, Roubaud-Baudron C, Avila-Funes JA, Amieva H. Infectious diseases and cognition: do we have to worry? Neurol Sci 2022; 43:6215-6224. [PMID: 35867217 PMCID: PMC9305033 DOI: 10.1007/s10072-022-06280-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 07/12/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Virgilio Hernandez-Ruiz
- UMR 1219, Univ. Bordeaux, INSERM, Bordeaux Population Health Research Center, 33000, Bordeaux, France.
- Instituto Nacional de Ciencias Médicas Y Nutrición Salvador Zubirán, Mexico City, Mexico.
| | - Luc Letenneur
- UMR 1219, Univ. Bordeaux, INSERM, Bordeaux Population Health Research Center, 33000, Bordeaux, France
| | - Tamas Fülöp
- Research Center On Aging, Geriatric Division, Department of Medicine, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Québec, Canada
| | - Catherine Helmer
- UMR 1219, Univ. Bordeaux, INSERM, Bordeaux Population Health Research Center, 33000, Bordeaux, France
| | - Claire Roubaud-Baudron
- CHU Bordeaux, Pôle de Gérontologie Clinique, 33000, Bordeaux, France
- Univ. Bordeaux, INSERM, UMR U1312 - BRIC, 33000, Bordeaux, France
| | - José-Alberto Avila-Funes
- UMR 1219, Univ. Bordeaux, INSERM, Bordeaux Population Health Research Center, 33000, Bordeaux, France
- Instituto Nacional de Ciencias Médicas Y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Hélène Amieva
- UMR 1219, Univ. Bordeaux, INSERM, Bordeaux Population Health Research Center, 33000, Bordeaux, France
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16
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Vavougios GD, Mavridis T, Artemiadis A, Krogfelt KA, Hadjigeorgiou G. Trained immunity in viral infections, Alzheimer's disease and multiple sclerosis: A convergence in type I interferon signalling and IFNβ-1a. Biochim Biophys Acta Mol Basis Dis 2022; 1868:166430. [DOI: 10.1016/j.bbadis.2022.166430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/02/2022] [Accepted: 05/02/2022] [Indexed: 12/14/2022]
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