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Tarlinton R, Tanasescu R, Shannon-Lowe C, Gran B. Ocrelizumab B cell depletion has no effect on HERV RNA expression in PBMC in MS patients. Mult Scler Relat Disord 2024; 86:105597. [PMID: 38598954 DOI: 10.1016/j.msard.2024.105597] [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: 11/02/2023] [Revised: 01/29/2024] [Accepted: 03/29/2024] [Indexed: 04/12/2024]
Abstract
BACKGROUND Epstein barr virus (EBV) infection of B cells is now understood to be one of the triggering events for the development of Multiple Sclerosis (MS), a progressive immune-mediated disease of the central nervous system. EBV infection is also linked to expression of human endogenous retroviruses (HERVs) of the HERV-W group, a further risk factor for the development of MS. Ocrelizumab is a high-potency disease-modifying treatment (DMT) for MS, which depletes B cells by targeting CD20. OBJECTIVES We studied the effects of ocrelizumab on gene expression in peripheral blood mononuclear cells (PBMC) from paired samples from 20 patients taken prior to and 6 months after beginning ocrelizumab therapy. We hypothesised that EBV and HERV-W loads would be lower in post-treatment samples. METHODS Samples were collected in Paxgene tubes, subject to RNA extraction and Illumina paired end short read mRNA sequencing with mapping of sequence reads to the human genome using Salmon and differential gene expression compared with DeSeq2. Mapping was also performed separately to the HERV-D database of HERV sequences and the EBV reference sequence. RESULTS Patient samples were more strongly clustered by individual rather than disease type (relapsing/remitting or primary progressive), treatment (pre and post), age, or sex. Fourteen genes, all clearly linked to B cell function were significantly down regulated in the post treatment samples. Interestingly only one pre-treatment sample had detectable EBV RNA and there were no significant differences in HERV expression (of any group) between pre- and post-treatment samples. CONCLUSIONS While EBV and HERV expression are clearly linked to triggering MS pathogenesis, it does not appear that high level expression of these viruses is a part of the ongoing disease process or that changes in virus load are associated with ocrelizumab treatment.
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Affiliation(s)
- Rachael Tarlinton
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom.
| | - Radu Tanasescu
- Department of Neurology, Nottingham University Hospitals NHS Trust, Queens Medical Centre, Derby Road, Nottingham, United Kingdom; School of Medicine, University of Nottingham, University Park Campus, Nottingham, United Kingdom
| | - Claire Shannon-Lowe
- Institute of Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Bruno Gran
- Department of Neurology, Nottingham University Hospitals NHS Trust, Queens Medical Centre, Derby Road, Nottingham, United Kingdom; School of Medicine, University of Nottingham, University Park Campus, Nottingham, United Kingdom
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2
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Takahashi Ueda M. Retrotransposon-derived transcripts and their functions in immunity and disease. Genes Genet Syst 2024; 98:305-319. [PMID: 38199240 DOI: 10.1266/ggs.23-00187] [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: 01/12/2024] Open
Abstract
Retrotransposons, which account for approximately 42% of the human genome, have been increasingly recognized as "non-self" pathogen-associated molecular patterns (PAMPs) due to their virus-like sequences. In abnormal conditions such as cancer and viral infections, retrotransposons that are aberrantly expressed due to impaired epigenetic suppression display PAMPs, leading to their recognition by pattern recognition receptors (PRRs) of the innate immune system and triggering inflammation. This viral mimicry mechanism has been observed in various human diseases, including aging and autoimmune disorders. However, recent evidence suggests that retrotransposons possess highly regulated immune reactivity and play important roles in the development and function of the immune system. In this review, I discuss a wide range of retrotransposon-derived transcripts, their role as targets in immune recognition, and the diseases associated with retrotransposon activity. Furthermore, I explore the implications of chimeric transcripts formed between retrotransposons and known gene mRNAs, which have been previously underestimated, for the increase of immune-related gene isoforms and their influence on immune function. Retrotransposon-derived transcripts have profound and multifaceted effects on immune system function. The aim of this comprehensive review is to provide a better understanding of the complex relationship between retrotransposon transcripts and immune defense.
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Affiliation(s)
- Mahoko Takahashi Ueda
- Department of Genomic Function and Diversity, Medical Research Institute, Tokyo Medical and Dental University
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3
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DePaula-Silva AB. The Contribution of Microglia and Brain-Infiltrating Macrophages to the Pathogenesis of Neuroinflammatory and Neurodegenerative Diseases during TMEV Infection of the Central Nervous System. Viruses 2024; 16:119. [PMID: 38257819 PMCID: PMC10819099 DOI: 10.3390/v16010119] [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: 12/05/2023] [Revised: 01/06/2024] [Accepted: 01/09/2024] [Indexed: 01/24/2024] Open
Abstract
The infection of the central nervous system (CNS) with neurotropic viruses induces neuroinflammation and is associated with the development of neuroinflammatory and neurodegenerative diseases, including multiple sclerosis and epilepsy. The activation of the innate and adaptive immune response, including microglial, macrophages, and T and B cells, while required for efficient viral control within the CNS, is also associated with neuropathology. Under healthy conditions, resident microglia play a pivotal role in maintaining CNS homeostasis. However, during pathological events, such as CNS viral infection, microglia become reactive, and immune cells from the periphery infiltrate into the brain, disrupting CNS homeostasis and contributing to disease development. Theiler's murine encephalomyelitis virus (TMEV), a neurotropic picornavirus, is used in two distinct mouse models: TMEV-induced demyelination disease (TMEV-IDD) and TMEV-induced seizures, representing mouse models of multiple sclerosis and epilepsy, respectively. These murine models have contributed substantially to our understanding of the pathophysiology of MS and seizures/epilepsy following viral infection, serving as critical tools for identifying pharmacological targetable pathways to modulate disease development. This review aims to discuss the host-pathogen interaction during a neurotropic picornavirus infection and to shed light on our current understanding of the multifaceted roles played by microglia and macrophages in the context of these two complexes viral-induced disease.
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Affiliation(s)
- Ana Beatriz DePaula-Silva
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT 84112, USA
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4
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Parthasarathy R, Wakefield D, Santiago FS, Kaakoush NO, Tedla N. Horizontal gene transfer and endogenous retroviruses as mechanisms for molecular mimicry. THE LANCET. MICROBE 2024; 5:e4-e5. [PMID: 37883987 DOI: 10.1016/s2666-5247(23)00316-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 09/26/2023] [Accepted: 09/26/2023] [Indexed: 10/28/2023]
Affiliation(s)
- Rohit Parthasarathy
- School of Biomedical Sciences, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW 2052, Australia
| | - Denis Wakefield
- School of Biomedical Sciences, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW 2052, Australia
| | - Fernando S Santiago
- School of Biomedical Sciences, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW 2052, Australia
| | - Nadeem O Kaakoush
- School of Biomedical Sciences, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Nicodemus Tedla
- School of Biomedical Sciences, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW 2052, Australia.
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5
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Frau J, Coghe G, Lorefice L, Fenu G, Cocco E. The Role of Microorganisms in the Etiopathogenesis of Demyelinating Diseases. Life (Basel) 2023; 13:1309. [PMID: 37374092 DOI: 10.3390/life13061309] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 05/28/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
Multiple sclerosis (MS), neuromyelitis optica (NMO) and myelin oligodendrocyte glycoprotein antibody disease (MOGAD) are inflammatory diseases of the central nervous system (CNS) with a multifactorial aetiology. Environmental factors are important for their development and microorganisms could play a determining role. They can directly damage the CNS, but their interaction with the immune system is even more important. The possible mechanisms involved include molecular mimicry, epitope spreading, bystander activation and the dual cell receptor theory. The role of Epstein-Barr virus (EBV) in MS has been definitely established, since being seropositive is a necessary condition for the onset of MS. EBV interacts with genetic and environmental factors, such as low levels of vitamin D and human endogenous retrovirus (HERV), another microorganism implicated in the disease. Many cases of onset or exacerbation of neuromyelitis optica spectrum disorder (NMOSD) have been described after infection with Mycobacterium tuberculosis, EBV and human immunodeficiency virus; however, no definite association with a virus has been found. A possible role has been suggested for Helicobacter pylori, in particular in individuals with aquaporin 4 antibodies. The onset of MOGAD could occur after an infection, mainly in the monophasic course of the disease. A role for the HERV in MOGAD has been hypothesized. In this review, we examined the current understanding of the involvement of infectious factors in MS, NMO and MOGAD. Our objective was to elucidate the roles of each microorganism in initiating the diseases and influencing their clinical progression. We aimed to discuss both the infectious factors that have a well-established role and those that have yielded conflicting results across various studies.
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Affiliation(s)
- Jessica Frau
- Multiple Sclerosis Centre, ASL Cagliari, 09126 Cagliari, Italy
| | - Giancarlo Coghe
- Multiple Sclerosis Centre, ASL Cagliari, 09126 Cagliari, Italy
| | - Lorena Lorefice
- Multiple Sclerosis Centre, ASL Cagliari, 09126 Cagliari, Italy
| | | | - Eleonora Cocco
- Multiple Sclerosis Centre, ASL Cagliari, 09126 Cagliari, Italy
- Department of Medical Sciences and Public Health, University of Cagliari, 09124 Cagliari, Italy
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Qi L, Li X, Zhang F, Zhu X, Zhao Q, Yang D, Hao S, Li T, Li X, Tian T, Feng J, Sun X, Wang X, Gao S, Wang H, Ye J, Cao S, He Y, Wang H, Wei B. VEGFR-3 signaling restrains the neuron-macrophage crosstalk during neurotropic viral infection. Cell Rep 2023; 42:112489. [PMID: 37167063 DOI: 10.1016/j.celrep.2023.112489] [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: 08/22/2022] [Revised: 03/07/2023] [Accepted: 04/24/2023] [Indexed: 05/13/2023] Open
Abstract
Upon recognizing danger signals produced by virally infected neurons, macrophages in the central nervous system (CNS) secrete multiple inflammatory cytokines to accelerate neuron apoptosis. The understanding is limited about which key effectors regulate macrophage-neuron crosstalk upon infection. We have used neurotropic-virus-infected murine models to identify that vascular endothelial growth factor receptor 3 (VEGFR-3) is upregulated in the CNS macrophages and that virally infected neurons secrete the ligand VEGF-C. When cultured with VEGF-C-containing supernatants from virally infected neurons, VEGFR-3+ macrophages suppress tumor necrosis factor α (TNF-α) secretion to reduce neuron apoptosis. Vegfr-3ΔLBD/ΔLBD (deletion of ligand-binding domain in myeloid cells) mice or mice treated with the VEGFR-3 kinase inhibitor exacerbate the severity of encephalitis, TNF-α production, and neuron apoptosis post Japanese encephalitis virus (JEV) infection. Activating VEGFR-3 or blocking TNF-α can reduce encephalitis and neuronal damage upon JEV infection. Altogether, we show that the inducible VEGF-C/VEGFR-3 module generates protective crosstalk between neurons and macrophages to alleviate CNS viral infection.
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Affiliation(s)
- Linlin Qi
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China; Shanghai Engineering Research Center of Organ Repair, School of Life Sciences, Shanghai University, Shanghai 200444, China; State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Wuhan 430071, China
| | - Xiaojing Li
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China; Shanghai Engineering Research Center of Organ Repair, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Fang Zhang
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China; State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Wuhan 430071, China; Cancer Center, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200072, China
| | - Xingguo Zhu
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China; Shanghai Engineering Research Center of Organ Repair, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Qi Zhao
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China; Shanghai Engineering Research Center of Organ Repair, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Dan Yang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Wuhan 430071, China
| | - Shujie Hao
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China; Shanghai Engineering Research Center of Organ Repair, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Tong Li
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Wuhan 430071, China
| | - Xiangyue Li
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China; Shanghai Engineering Research Center of Organ Repair, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Taikun Tian
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China; Shanghai Engineering Research Center of Organ Repair, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Jian Feng
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China; Shanghai Engineering Research Center of Organ Repair, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Xiaochen Sun
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China; Shanghai Engineering Research Center of Organ Repair, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Xilin Wang
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China; Shanghai Engineering Research Center of Organ Repair, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Shangyan Gao
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China
| | - Hanzhong Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Wuhan 430071, China
| | - Jing Ye
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Shengbo Cao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yulong He
- Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, State Key Laboratory of Radiation Medicine and Protection, Cam-Su Genomic Resources Center, Soochow University, Suzhou 215123, China
| | - Hongyan Wang
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China; School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China.
| | - Bin Wei
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University (The Sixth People's Hospital of Nantong), School of Medicine, Shanghai University, Nantong 226011, China; Shanghai Engineering Research Center of Organ Repair, School of Life Sciences, Shanghai University, Shanghai 200444, China; State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Wuhan 430071, China; Cancer Center, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200072, China; Department of Laboratory Medicine, Gene Diagnosis Research Center, Fujian Key Laboratory of Laboratory Medicine, The First Affiliated Hospital, Fujian Medical University, Fuzhou 350000, China.
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7
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Tovo PA, Marozio L, Abbona G, Calvi C, Frezet F, Gambarino S, Dini M, Benedetto C, Galliano I, Bergallo M. Pregnancy Is Associated with Impaired Transcription of Human Endogenous Retroviruses and of TRIM28 and SETDB1, Particularly in Mothers Affected by Multiple Sclerosis. Viruses 2023; 15:v15030710. [PMID: 36992419 PMCID: PMC10051116 DOI: 10.3390/v15030710] [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: 02/07/2023] [Revised: 03/01/2023] [Accepted: 03/06/2023] [Indexed: 03/12/2023] Open
Abstract
Accumulating evidence highlights the pathogenetic role of human endogenous retroviruses (HERVs) in eliciting and maintaining multiple sclerosis (MS). Epigenetic mechanisms, such as those regulated by TRIM 28 and SETDB1, are implicated in HERV activation and in neuroinflammatory disorders, including MS. Pregnancy markedly improves the course of MS, but no study explored the expressions of HERVs and of TRIM28 and SETDB1 during gestation. Using a polymerase chain reaction real-time Taqman amplification assay, we assessed and compared the transcriptional levels of pol genes of HERV-H, HERV-K, HERV-W; of env genes of Syncytin (SYN)1, SYN2, and multiple sclerosis associated retrovirus (MSRV); and of TRIM28 and SETDB1 in peripheral blood and placenta from 20 mothers affected by MS; from 27 healthy mothers, in cord blood from their neonates; and in blood from healthy women of child-bearing age. The HERV mRNA levels were significantly lower in pregnant than in nonpregnant women. Expressions of all HERVs were downregulated in the chorion and in the decidua basalis of MS mothers compared to healthy mothers. The former also showed lower mRNA levels of HERV-K-pol and of SYN1, SYN2, and MSRV in peripheral blood. Significantly lower expressions of TRIM28 and SETDB1 also emerged in pregnant vs. nonpregnant women and in blood, chorion, and decidua of mothers with MS vs. healthy mothers. In contrast, HERV and TRIM28/SETDB1 expressions were comparable between their neonates. These results show that gestation is characterized by impaired expressions of HERVs and TRIM28/SETDB1, particularly in mothers with MS. Given the beneficial effects of pregnancy on MS and the wealth of data suggesting the putative contribution of HERVs and epigenetic processes in the pathogenesis of the disease, our findings may further support innovative therapeutic interventions to block HERV activation and to control aberrant epigenetic pathways in MS-affected patients.
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Affiliation(s)
- Pier-Angelo Tovo
- Department of Public Health and Pediatric Sciences, University of Turin, 10126 Turin, Italy
- Correspondence: (P.-A.T.); (M.B.)
| | - Luca Marozio
- Department of Surgical Sciences, Obstetrics and Gynecology 1, University of Turin, 10126 Turin, Italy
| | - Giancarlo Abbona
- Pathology Unit, Department Laboratory Medicine, AOU Città della Salute e della Scienza di Torino, 10126 Turin, Italy
| | - Cristina Calvi
- Department of Public Health and Pediatric Sciences, University of Turin, 10126 Turin, Italy
- Pediatric Laboratory, Department of Public Health and Pediatric Sciences, University of Turin, 10126 Turin, Italy
| | - Federica Frezet
- Department of Surgical Sciences, Obstetrics and Gynecology 1, University of Turin, 10126 Turin, Italy
| | - Stefano Gambarino
- Pediatric Laboratory, Department of Public Health and Pediatric Sciences, University of Turin, 10126 Turin, Italy
| | - Maddalena Dini
- Pediatric Laboratory, Department of Public Health and Pediatric Sciences, University of Turin, 10126 Turin, Italy
| | - Chiara Benedetto
- Department of Surgical Sciences, Obstetrics and Gynecology 1, University of Turin, 10126 Turin, Italy
| | - Ilaria Galliano
- Department of Public Health and Pediatric Sciences, University of Turin, 10126 Turin, Italy
- Pediatric Laboratory, Department of Public Health and Pediatric Sciences, University of Turin, 10126 Turin, Italy
| | - Massimiliano Bergallo
- Department of Public Health and Pediatric Sciences, University of Turin, 10126 Turin, Italy
- Pediatric Laboratory, Department of Public Health and Pediatric Sciences, University of Turin, 10126 Turin, Italy
- Correspondence: (P.-A.T.); (M.B.)
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8
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Elkjaer ML, Simon L, Frisch T, Bente LM, Kacprowski T, Thomassen M, Reynolds R, Baumbach J, Röttger R, Illes Z. Hypothesis of a potential BrainBiota and its relation to CNS autoimmune inflammation. Front Immunol 2022; 13:1043579. [PMID: 36532064 PMCID: PMC9756883 DOI: 10.3389/fimmu.2022.1043579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 11/16/2022] [Indexed: 12/03/2022] Open
Abstract
Infectious agents have been long considered to play a role in the pathogenesis of neurological diseases as part of the interaction between genetic susceptibility and the environment. The role of bacteria in CNS autoimmunity has also been highlighted by changes in the diversity of gut microbiota in patients with neurological diseases such as Parkinson's disease, Alzheimer disease and multiple sclerosis, emphasizing the role of the gut-brain axis. We discuss the hypothesis of a brain microbiota, the BrainBiota: bacteria living in symbiosis with brain cells. Existence of various bacteria in the human brain is suggested by morphological evidence, presence of bacterial proteins, metabolites, transcripts and mucosal-associated invariant T cells. Based on our data, we discuss the hypothesis that these bacteria are an integral part of brain development and immune tolerance as well as directly linked to the gut microbiome. We further suggest that changes of the BrainBiota during brain diseases may be the consequence or cause of the chronic inflammation similarly to the gut microbiota.
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Affiliation(s)
- Maria L. Elkjaer
- Department of Neurology, Odense University Hospital, Odense, Denmark,BRIDGE, Department of Clinical Research, University of Southern Denmark, Odense, Denmark,Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark,*Correspondence: Maria L. Elkjaer, ; Zsolt Illes,
| | - Lukas Simon
- Center for Precision Health, School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Tobias Frisch
- Department of Mathematics and Computer Science, University of Southern Denmark, Odense, Denmark
| | - Lisa-Marie Bente
- Division Data Science in Biomedicine, Peter L. Reichertz Institute for Medical Informatics, Technische Universität Braunschweig and Hannover Medical School, Braunschweig, Germany,Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunchweig, Germany
| | - Tim Kacprowski
- Division Data Science in Biomedicine, Peter L. Reichertz Institute for Medical Informatics, Technische Universität Braunschweig and Hannover Medical School, Braunschweig, Germany,Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunchweig, Germany
| | - Mads Thomassen
- BRIDGE, Department of Clinical Research, University of Southern Denmark, Odense, Denmark,Research Unit of Human Genetics, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Richard Reynolds
- Department of Brain Sciences, Imperial College, London, United Kingdom,Centre for Molecular Neuropathology, LKC School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Jan Baumbach
- Chair of Computational Systems Biology, University of Hamburg, Hamburg, Germany
| | - Richard Röttger
- Department of Mathematics and Computer Science, University of Southern Denmark, Odense, Denmark
| | - Zsolt Illes
- Department of Neurology, Odense University Hospital, Odense, Denmark,BRIDGE, Department of Clinical Research, University of Southern Denmark, Odense, Denmark,Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark,*Correspondence: Maria L. Elkjaer, ; Zsolt Illes,
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9
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Bjørklund G, Zou L, Peana M, Chasapis CT, Hangan T, Lu J, Maes M. The Role of the Thioredoxin System in Brain Diseases. Antioxidants (Basel) 2022; 11:2161. [PMID: 36358532 PMCID: PMC9686621 DOI: 10.3390/antiox11112161] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/23/2022] [Accepted: 10/28/2022] [Indexed: 08/08/2023] Open
Abstract
The thioredoxin system, consisting of thioredoxin (Trx), thioredoxin reductase (TrxR), and NADPH, plays a fundamental role in the control of antioxidant defenses, cell proliferation, redox states, and apoptosis. Aberrations in the Trx system may lead to increased oxidative stress toxicity and neurodegenerative processes. This study reviews the role of the Trx system in the pathophysiology and treatment of Alzheimer's, Parkinson's and Huntington's diseases, brain stroke, and multiple sclerosis. Trx system plays an important role in the pathophysiology of those disorders via multiple interactions through oxidative stress, apoptotic, neuro-immune, and pro-survival pathways. Multiple aberrations in Trx and TrxR systems related to other redox systems and their multiple reciprocal relationships with the neurodegenerative, neuro-inflammatory, and neuro-oxidative pathways are here analyzed. Genetic and environmental factors (nutrition, metals, and toxins) may impact the function of the Trx system, thereby contributing to neuropsychiatric disease. Aberrations in the Trx and TrxR systems could be a promising drug target to prevent and treat neurodegenerative, neuro-inflammatory, neuro-oxidative stress processes, and related brain disorders.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Toften 24, 8610 Mo i Rana, Norway
| | - Lili Zou
- Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, College of Basic Medical Sciences, China Three Gorges University, Yichang 443002, China
| | - Massimiliano Peana
- Department of Chemical, Physical, Mathematical and Natural Sciences, University of Sassari, Via Vienna 2, 07100 Sassari, Italy
| | - Christos T. Chasapis
- Institute of Chemical Biology, National Hellenic Research Foundation, 11635 Athens, Greece
| | - Tony Hangan
- Faculty of Medicine, Ovidius University of Constanta, 900470 Constanta, Romania
| | - Jun Lu
- School of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
| | - Michael Maes
- Department of Psychiatry, Faculty of Medicine, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand
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10
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Ilse V, Scholz R, Wermann M, Naumann M, Staege MS, Roßner S, Cynis H. Immunogenicity of the Envelope Surface Unit of Human Endogenous Retrovirus K18 in Mice. Int J Mol Sci 2022; 23:ijms23158330. [PMID: 35955468 PMCID: PMC9369184 DOI: 10.3390/ijms23158330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/21/2022] [Accepted: 07/25/2022] [Indexed: 02/06/2023] Open
Abstract
The triggers for the development of multiple sclerosis (MS) have not been fully understood to date. One hypothesis proposes a viral etiology. Interestingly, viral proteins from human endogenous retroviruses (HERVs) may play a role in the pathogenesis of MS. Allelic variants of the HERV-K18 env gene represent a genetic risk factor for MS, and the envelope protein is considered to be an Epstein–Barr virus-trans-activated superantigen. To further specify a possible role for HERV-K18 in MS, the present study examined the immunogenicity of the purified surface unit (SU). HERV-K18(SU) induced envelope-specific plasma IgG in immunized mice and triggered proliferation of T cells isolated from these mice. It did not trigger phenotypic changes in a mouse model of experimental autoimmune encephalomyelitis. Further studies are needed to investigate the underlying mechanisms of HERV-K18 interaction with immune system regulators in more detail.
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Affiliation(s)
- Victoria Ilse
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany; (V.I.); (R.S.); (M.W.); (M.N.)
| | - Rebekka Scholz
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany; (V.I.); (R.S.); (M.W.); (M.N.)
| | - Michael Wermann
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany; (V.I.); (R.S.); (M.W.); (M.N.)
| | - Marcel Naumann
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany; (V.I.); (R.S.); (M.W.); (M.N.)
| | - Martin S. Staege
- Department of Surgical and Conservative Pediatrics and Adolescent Medicine, Medical Faculty, Martin Luther University Halle-Wittenberg, Ernst-Grube-Str. 40, 06097 Halle, Germany;
| | - Steffen Roßner
- Paul Flechsig Institute for Brain Research, Leipzig University, Liebigstraße 19, 04103 Leipzig, Germany;
| | - Holger Cynis
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, Weinbergweg 22, 06120 Halle, Germany; (V.I.); (R.S.); (M.W.); (M.N.)
- Correspondence: ; Tel.: +49-345-13142835; Fax: +49-345-13142801
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11
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Maple PA, Ascherio A, Cohen JI, Cutter G, Giovannoni G, Shannon-Lowe C, Tanasescu R, Gran B. The Potential for EBV Vaccines to Prevent Multiple Sclerosis. Front Neurol 2022; 13:887794. [PMID: 35812097 PMCID: PMC9263514 DOI: 10.3389/fneur.2022.887794] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 05/04/2022] [Indexed: 01/22/2023] Open
Abstract
There is increasing evidence suggesting that Epstein-Barr virus infection is a causative factor of multiple sclerosis (MS). Epstein-Barr virus (EBV) is a human herpesvirus, Human Gammaherpesvirus 4. EBV infection shows two peaks: firstly, during early childhood and, secondly during the teenage years. Approximately, 90-95% of adults have been infected with EBV and for many this will have been a subclinical event. EBV infection can be associated with significant morbidity and mortality; for example, primary infection in older children or adults is the leading cause of infectious mononucleosis (IM). A disrupted immune response either iatrogenically induced or through genetic defects can result in lymphoproliferative disease. Finally, EBV is oncogenic and is associated with several malignancies. For these reasons, vaccination to prevent the damaging aspects of EBV infection is an attractive intervention. No EBV vaccines have been licensed and the prophylactic vaccine furthest along in clinical trials contains the major virus glycoprotein gp350. In a phase 2 study, the vaccine reduced the rate of IM by 78% but did not prevent EBV infection. An EBV vaccine to prevent IM in adolescence or young adulthood is the most likely population-based vaccine strategy to be tested and adopted. National registry studies will need to be done to track the incidence of MS in EBV-vaccinated and unvaccinated people to see an effect of the vaccine on MS. Assessment of vaccine efficacy with MS being a delayed consequence of EBV infection with the average age of onset being approximately 30 years of age represents multiple challenges.
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Affiliation(s)
- Peter A. Maple
- Division of Clinical Neuroscience, Section of Clinical Neurology, University of Nottingham, Nottingham, United Kingdom,Department of Neurology, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
| | - Alberto Ascherio
- Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA, United States,Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA, United States
| | - Jeffrey I. Cohen
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Gary Cutter
- School of Public Health, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Gavin Giovannoni
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Claire Shannon-Lowe
- Institute of Immunology and Immunotherapy, The University of Birmingham, Birmingham, United Kingdom
| | - Radu Tanasescu
- Department of Neurology, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom,Mental Health and Clinical Neurosciences Academic Unit, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Bruno Gran
- Department of Neurology, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom,Mental Health and Clinical Neurosciences Academic Unit, School of Medicine, University of Nottingham, Nottingham, United Kingdom,*Correspondence: Bruno Gran
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12
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Oh J, Bar-Or A. Emerging therapies to target CNS pathophysiology in multiple sclerosis. Nat Rev Neurol 2022; 18:466-475. [PMID: 35697862 DOI: 10.1038/s41582-022-00675-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2022] [Indexed: 12/13/2022]
Abstract
The rapidly evolving therapeutic landscape of multiple sclerosis (MS) has contributed to paradigm shifts in our understanding of the biological mechanisms that contribute to CNS injury and in treatment philosophies. Opportunities remain to further improve treatment of relapsing-remitting MS, but two major therapeutic gaps are the limiting of progressive disease mechanisms and the repair of CNS injury. In this Review, we provide an overview of selected emerging therapies that predominantly target processes within the CNS that are thought to be involved in limiting non-relapsing, progressive disease injury or promoting tissue repair. Among these, we consider agents that modulate adaptive and innate CNS-compartmentalized inflammation, which can be mediated by infiltrating immune cells and/or resident CNS cells, including microglia and astrocytes. We also discuss agents that target degenerative disease mechanisms, agents that might confer neuroprotection, and agents that create a more favourable environment for or actively contribute to oligodendrocyte precursor cell differentiation, remyelination and axonal regeneration. We focus on agents that are novel for MS, that are known to or are presumed to penetrate the CNS, and that have already entered early stages of development in MS clinical trials.
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Affiliation(s)
- Jiwon Oh
- Division of Neurology, Department of Medicine, St. Michael's Hospital, University of Toronto, Ontario, Canada.,Department of Neurology, Johns Hopkins University, Baltimore, MD, USA
| | - Amit Bar-Or
- Center for Neuroinflammation and Experimental Therapeutics, and Multiple Sclerosis Division, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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13
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The Role of Transposable Elements of the Human Genome in Neuronal Function and Pathology. Int J Mol Sci 2022; 23:ijms23105847. [PMID: 35628657 PMCID: PMC9148063 DOI: 10.3390/ijms23105847] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 12/13/2022] Open
Abstract
Transposable elements (TEs) have been extensively studied for decades. In recent years, the introduction of whole-genome and whole-transcriptome approaches, as well as single-cell resolution techniques, provided a breakthrough that uncovered TE involvement in host gene expression regulation underlying multiple normal and pathological processes. Of particular interest is increased TE activity in neuronal tissue, and specifically in the hippocampus, that was repeatedly demonstrated in multiple experiments. On the other hand, numerous neuropathologies are associated with TE dysregulation. Here, we provide a comprehensive review of literature about the role of TEs in neurons published over the last three decades. The first chapter of the present review describes known mechanisms of TE interaction with host genomes in general, with the focus on mammalian and human TEs; the second chapter provides examples of TE exaptation in normal neuronal tissue, including TE involvement in neuronal differentiation and plasticity; and the last chapter lists TE-related neuropathologies. We sought to provide specific molecular mechanisms of TE involvement in neuron-specific processes whenever possible; however, in many cases, only phenomenological reports were available. This underscores the importance of further studies in this area.
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14
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Irfan SA, Murtaza M, Ahmed A, Altaf H, Ali AA, Shabbir N, Baig MMA. PROMISING ROLE OF TEMELIMAB IN MULTIPLE SCLEROSIS TREATMENT. Mult Scler Relat Disord 2022; 61:103743. [DOI: 10.1016/j.msard.2022.103743] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 01/30/2022] [Accepted: 03/11/2022] [Indexed: 11/25/2022]
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15
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Viral Proteins with PxxP and PY Motifs May Play a Role in Multiple Sclerosis. Viruses 2022; 14:v14020281. [PMID: 35215874 PMCID: PMC8879583 DOI: 10.3390/v14020281] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/19/2022] [Accepted: 01/26/2022] [Indexed: 02/04/2023] Open
Abstract
Multiple sclerosis (MS) is a debilitating disease that arises from immune system attacks to the protective myelin sheath that covers nerve fibers and ensures optimal communication between brain and body. Although the cause of MS is unknown, a number of factors, which include viruses, have been identified as increasing the risk of displaying MS symptoms. Specifically, the ubiquitous and highly prevalent Epstein–Barr virus, human herpesvirus 6, cytomegalovirus, varicella–zoster virus, and other viruses have been identified as potential triggering agents. In this review, we examine the specific role of proline-rich proteins encoded by these viruses and their potential role in MS at a molecular level.
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16
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Latifi T, Zebardast A, Marashi SM. The role of human endogenous retroviruses (HERVs) in Multiple Sclerosis and the plausible interplay between HERVs, Epstein-Barr virus infection, and vitamin D. Mult Scler Relat Disord 2022; 57:103318. [PMID: 35158423 DOI: 10.1016/j.msard.2021.103318] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/19/2021] [Accepted: 10/06/2021] [Indexed: 12/30/2022]
Abstract
Multiple Sclerosis (MS) is one of the chronic inflammatory diseases with neurological disability in the central nervous system (CNS). Although the exact cause of MS is still largely unknown, both genetic and environmental factors are thought to play a role in disease risk. Human Endogenous Retroviruses (HERVs) are endogenous viral elements of the human genome whose expression is associated with MS. HERVs are normally silenced or expressed at low levels, although their expression is higher in MS than in the healthy population. Several studies highlighted the plausible interaction between HERVs and other MS risk factors, including viral infection like Epstein-Barr viruses and vitamin D deficiency which may lead to high expression of HERVs in these patients. Understanding how HERVs act in this scenario can improve our understanding towards MS etiology and may lead to the development of antiretroviral therapies in these patients. Here in this review, we try to examine the different HERVs expression implicated in MS and their association with EBV infection and vitamin D status.
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Affiliation(s)
- Tayebeh Latifi
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Arghavan Zebardast
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Sayed Mahdi Marashi
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
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17
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Dumitrescu L, Papathanasiou A, Coclitu C, Constantinescu CS, Popescu BO, Tanasescu R. Beta interferons as immunotherapy in multiple sclerosis: a new outlook on a classic drug during the COVID-19 pandemic. QJM 2021; 114:691-697. [PMID: 33486513 PMCID: PMC7928608 DOI: 10.1093/qjmed/hcaa348] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 12/22/2020] [Indexed: 12/16/2022] Open
Abstract
Beta interferons (IFN-β) are pleiotropic cytokines with antiviral properties. They play important roles in the pathogenesis of multiple sclerosis (MS), an incurable immune-mediated disorder of the central nervous system. The clinical expression of MS is heterogeneous, with relapses of neuroinflammation and with disability accrual in considerable part unrelated to the attacks. The injectable recombinant IFN-β preparations are the first approved disease-modifying treatments for MS. They have moderate efficacy in reducing the frequency of relapses, but good long-term cost-efficacy and safety profiles, so are still widely used. They have some tolerability and adherence issues, partly mitigated in recent years by the introduction of a PEGylated formulation and use of 'smart' autoinjector devices. Their general impact on long-term disability is modest but could be further improved by developing accurate tools for identifying the patient profile of best responders to IFN-β. Here, we present the IFN-β-based immunomodulatory therapeutic approaches in MS, highlighting their place in the current coronavirus disease (COVID-19) pandemic. The potential role of IFN-β in the treatment of COVID-19 is also briefly discussed.
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Affiliation(s)
- L Dumitrescu
- From the Department of Clinical Neurosciences, University of Medicine and Pharmacy Carol Davila, Bucharest, Romania
- Department of Neurology, Colentina Hospital, Bucharest, Romania
| | - A Papathanasiou
- Department of Neurology, Queen’s Medical Centre, Nottingham University Hospitals, Nottingham, UK
| | - C Coclitu
- Department of Multiple Sclerosis and Neuroimmunology, CHU Grenoble, Grenoble, France
| | - C S Constantinescu
- Department of Neurology, Queen’s Medical Centre, Nottingham University Hospitals, Nottingham, UK
- Academic Clinical Neurology, Division of Clinical Neuroscience, C Floor, South Block, Queen's Medical Centre, Derby Road, NG7 2UH, Nottingham, UK
| | - B O Popescu
- From the Department of Clinical Neurosciences, University of Medicine and Pharmacy Carol Davila, Bucharest, Romania
- Department of Neurology, Colentina Hospital, Bucharest, Romania
| | - R Tanasescu
- Department of Neurology, Queen’s Medical Centre, Nottingham University Hospitals, Nottingham, UK
- Academic Clinical Neurology, Division of Clinical Neuroscience, C Floor, South Block, Queen's Medical Centre, Derby Road, NG7 2UH, Nottingham, UK
- Address correspondence to Dr Radu Tanasescu, c/o Division of Clinical Neuroscience, Section of Clinical Neurology, University of Nottingham, Queen’s Medical Centre, C Floor South Block, Nottingham NG7 2UH, UK.
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18
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Posso-Osorio I, Tobón GJ, Cañas CA. Human endogenous retroviruses (HERV) and non-HERV viruses incorporated into the human genome and their role in the development of autoimmune diseases. J Transl Autoimmun 2021; 4:100137. [PMID: 34917914 PMCID: PMC8669383 DOI: 10.1016/j.jtauto.2021.100137] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 11/18/2021] [Accepted: 12/08/2021] [Indexed: 12/12/2022] Open
Abstract
Genomic incorporation of viruses as human endogenous retroviruses (HERVs) are components of our genome that possibly originated by incorporating ancestral of exogenous viruses. Their roles in the evolution of the human genome, gene expression, and the pathogenesis of autoimmune diseases (ADs) and neoplastic phenomena are the subject of intense research. This review analyzes the evolutionary and virological aspects of HERVs and other viruses that incorporate their genome into the human genome and have known role in the genesis of ADs. These insights are helpful to understand further the possible role in autoimmunity genesis of HERVs, other ancestral viruses no HERVs and modern viruses with the ability to incorporate into the human genome or interact with HERVs.
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Affiliation(s)
- Iván Posso-Osorio
- CIRAT: Centro de Investigación en Reumatología, Autoinmunidad y Medicina Traslacional, Fundación Valle Del Lili and Universidad Icesi, Cali, Colombia.,Fundación Valle del Lili, Rheumatology Unit, Cali, Colombia
| | - Gabriel J Tobón
- Fundación Valle del Lili, Rheumatology Unit, Cali, Colombia.,Department of Medical Microbiology, Immunology and Cell Biology. Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Carlos A Cañas
- CIRAT: Centro de Investigación en Reumatología, Autoinmunidad y Medicina Traslacional, Fundación Valle Del Lili and Universidad Icesi, Cali, Colombia.,Fundación Valle del Lili, Rheumatology Unit, Cali, Colombia
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19
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Helmy M, Selvarajoo K. Systems Biology to Understand and Regulate Human Retroviral Proinflammatory Response. Front Immunol 2021; 12:736349. [PMID: 34867957 PMCID: PMC8635014 DOI: 10.3389/fimmu.2021.736349] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 10/21/2021] [Indexed: 01/13/2023] Open
Abstract
The majority of human genome are non-coding genes. Recent research have revealed that about half of these genome sequences make up of transposable elements (TEs). A branch of these belong to the endogenous retroviruses (ERVs), which are germline viral infection that occurred over millions of years ago. They are generally harmless as evolutionary mutations have made them unable to produce viral agents and are mostly epigenetically silenced. Nevertheless, ERVs are able to express by still unknown mechanisms and recent evidences have shown links between ERVs and major proinflammatory diseases and cancers. The major challenge is to elucidate a detailed mechanistic understanding between them, so that novel therapeutic approaches can be explored. Here, we provide a brief overview of TEs, human ERVs and their links to microbiome, innate immune response, proinflammatory diseases and cancer. Finally, we recommend the employment of systems biology approaches for future HERV research.
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Affiliation(s)
- Mohamed Helmy
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (ASTAR), Singapore, Singapore
- Department of Computer Science, Lakehead University, Thunder Bay, ON, Canada
| | - Kumar Selvarajoo
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (ASTAR), Singapore, Singapore
- Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (ASTAR), Singapore, Singapore
- Synthetic Biology Translational Research Program & SynCTI, Yong Loo Lin School of Medicine, National University of Singapore (NUS), Kent Ridge, Singapore
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20
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Schroeter CB, Huntemann N, Bock S, Nelke C, Kremer D, Pfeffer K, Meuth SG, Ruck T. Crosstalk of Microorganisms and Immune Responses in Autoimmune Neuroinflammation: A Focus on Regulatory T Cells. Front Immunol 2021; 12:747143. [PMID: 34691057 PMCID: PMC8529161 DOI: 10.3389/fimmu.2021.747143] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 09/20/2021] [Indexed: 12/22/2022] Open
Abstract
Regulatory T cells (Tregs) are the major determinant of peripheral immune tolerance. Many Treg subsets have been described, however thymus-derived and peripherally induced Tregs remain the most important subpopulations. In multiple sclerosis, a prototypical autoimmune disorder of the central nervous system, Treg dysfunction is a pathogenic hallmark. In contrast, induction of Treg proliferation and enhancement of their function are central immune evasion mechanisms of infectious pathogens. In accordance, Treg expansion is compartmentalized to tissues with high viral replication and prolonged in chronic infections. In friend retrovirus infection, Treg expansion is mainly based on excessive interleukin-2 production by infected effector T cells. Moreover, pathogens seem also to enhance Treg functions as shown in human immunodeficiency virus infection, where Tregs express higher levels of effector molecules such as cytotoxic T-lymphocyte-associated protein 4, CD39 and cAMP and show increased suppressive capacity. Thus, insights into the molecular mechanisms by which intracellular pathogens alter Treg functions might aid to find new therapeutic approaches to target central nervous system autoimmunity. In this review, we summarize the current knowledge of the role of pathogens for Treg function in the context of autoimmune neuroinflammation. We discuss the mechanistic implications for future therapies and provide an outlook for new research directions.
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Affiliation(s)
- Christina B Schroeter
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Niklas Huntemann
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Stefanie Bock
- Department of Neurology With Institute of Translational Neurology, University of Münster, Münster, Germany
| | - Christopher Nelke
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - David Kremer
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Klaus Pfeffer
- Institute of Medical Microbiology and Hospital Hygiene, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Sven G Meuth
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Tobias Ruck
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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21
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Ravel-Godreuil C, Znaidi R, Bonnifet T, Joshi RL, Fuchs J. Transposable elements as new players in neurodegenerative diseases. FEBS Lett 2021; 595:2733-2755. [PMID: 34626428 DOI: 10.1002/1873-3468.14205] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/23/2021] [Accepted: 10/03/2021] [Indexed: 01/02/2023]
Abstract
Neurodegenerative diseases (NDs), including the most prevalent Alzheimer's disease and Parkinson disease, share common pathological features. Despite decades of gene-centric approaches, the molecular mechanisms underlying these diseases remain widely elusive. In recent years, transposable elements (TEs), long considered 'junk' DNA, have gained growing interest as pathogenic players in NDs. Age is the major risk factor for most NDs, and several repressive mechanisms of TEs, such as heterochromatinization, fail with age. Indeed, heterochromatin relaxation leading to TE derepression has been reported in various models of neurodegeneration and NDs. There is also evidence that certain pathogenic proteins involved in NDs (e.g., tau, TDP-43) may control the expression of TEs. The deleterious consequences of TE activation are not well known but they could include DNA damage and genomic instability, altered host gene expression, and/or neuroinflammation, which are common hallmarks of neurodegeneration and aging. TEs might thus represent an overlooked pathogenic culprit for both brain aging and neurodegeneration. Certain pathological effects of TEs might be prevented by inhibiting their activity, pointing to TEs as novel targets for neuroprotection.
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Affiliation(s)
- Camille Ravel-Godreuil
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Rania Znaidi
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Tom Bonnifet
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Rajiv L Joshi
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Julia Fuchs
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
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22
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Zarghami A, Li Y, Claflin SB, van der Mei I, Taylor BV. Role of environmental factors in multiple sclerosis. Expert Rev Neurother 2021; 21:1389-1408. [PMID: 34494502 DOI: 10.1080/14737175.2021.1978843] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
INTRODUCTION Environmental factors play a significant role in the pathogenesis and progression of multiple sclerosis (MS), either acting alone or by interacting with other environmental or genetic factors. This cumulative exposure to external risk factors is highly complex and highly variable between individuals. AREAS COVERED We narratively review the current evidence on the role of environment-specific risk factors in MS onset and progression, as well as the effect of gene-environment interactions and the timing of exposure We have reviewed the latest literature, by Ovid Medline, retrieving the most recently published systematic reviews and/or meta-analyses and more recent studies not previously included in meta-analyses or systematic reviews. EXPERT OPINION There is some good evidence supporting the impact of some environmental risk factors in increasing the risk of developing MS. Tobacco smoking, low vitamin D levels and/or low sun exposure, Epstein Barr Virus (EBV) seropositivity and a history of infectious mononucleosis may increase the risk of developing MS. Additionally, there is some evidence that gene-smoking, gene-EBV, and smoking-EBV interactions additively affect the risk of MS onset. However, the evidence for a role of other environmental factors in MS progression is limited. Finally, there is some evidence that tobacco smoking, insufficient vitamin D levels and/or sun exposure have impacts on MS phenotypes and various markers of disease activity including relapse, disability progression and MRI findings. Clearly the effect of environmental factors on MS disease course is an area that requires significantly more research.
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Affiliation(s)
- Amin Zarghami
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Ying Li
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Suzi B Claflin
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Ingrid van der Mei
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Bruce V Taylor
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
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23
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Jakhmola S, Upadhyay A, Jain K, Mishra A, Jha HC. Herpesviruses and the hidden links to Multiple Sclerosis neuropathology. J Neuroimmunol 2021; 358:577636. [PMID: 34174587 DOI: 10.1016/j.jneuroim.2021.577636] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/01/2021] [Accepted: 06/17/2021] [Indexed: 01/08/2023]
Abstract
Herpesviruses like Epstein-Barr virus, human herpesvirus (HHV)-6, HHV-1, VZV, and human endogenous retroviruses, have an age-old clinical association with multiple sclerosis (MS). MS is an autoimmune disease of the nervous system wherein the myelin sheath deteriorates. The most popular mode of virus mediated immune system manipulation is molecular mimicry. Numerous herpesvirus antigens are similar to myelin proteins. Other mechanisms described here include the activity of cytokines and autoantibodies produced by the autoreactive T and B cells, respectively, viral déjà vu, epitope spreading, CD46 receptor engagement, impaired remyelination etc. Overall, this review addresses the host-parasite association of viruses with MS.
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Affiliation(s)
- Shweta Jakhmola
- Infection Bioengineering Group, Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, India
| | - Arun Upadhyay
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology, Jodhpur, India
| | - Khushboo Jain
- Infection Bioengineering Group, Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology, Jodhpur, India
| | - Hem Chandra Jha
- Infection Bioengineering Group, Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, India.
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24
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Cinek O, Kramna L, Odeh R, Alassaf A, Ibekwe MAU, Ahmadov G, Elmahi BME, Mekki H, Lebl J, Abdullah MA. Eukaryotic viruses in the fecal virome at the onset of type 1 diabetes: A study from four geographically distant African and Asian countries. Pediatr Diabetes 2021; 22:558-566. [PMID: 33786936 DOI: 10.1111/pedi.13207] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 12/21/2020] [Accepted: 02/26/2021] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVES Studies of the fecal virome in type 1 diabetes (T1D) have been limited to populations of Europe and the United States. We therefore sought to characterize the stool virome in children after onset of T1D and in matched control subjects from four geographically distant African and Asian countries. METHODS Samples of stool were collected from 73 children and adolescents shortly after T1D onset (Azerbaijan 19, Jordan 20, Nigeria 14, Sudan 20) and 105 matched control subjects of similar age and locale. Metagenomic sequencing of the DNA and RNA virome was performed, and virus positivity was defined as more than 0.001% of reads of the sample. Selected viruses were also quantified using real-time PCR. Conditional logistic regression was used to model associations with eukaryotic virus positivity. RESULTS Signals of 387 different viral species were detected; at least one eukaryotic virus was detected in 71% case and 65% control samples. Neither of observed eukaryotic virus species or genera differed in frequency between children with T1D and controls. There was a suggestive association of the total count of different viral genera per sample between cases (1.45 genera) and controls (1.10 genera, OR 1.24, 95%CI 0.98-1.57), and an unplanned subanalysis suggested marginally more frequent endogenous retrovirus signal in cases (in 28.8% vs. in 8.6% controls, OR = 4.55, 95%CI 1.72-12). CONCLUSIONS No clear and consistent association with T1D was observed in the fecal viromes from four distant non-European populations. The finding of borderline associations of human endogenous retroviruses merits further exploration.
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Affiliation(s)
- Ondrej Cinek
- Department of Pediatrics, Second Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Lenka Kramna
- Department of Pediatrics, Second Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Rasha Odeh
- Department of Pediatrics, School of Medicine, University of Jordan, Amman, Jordan
| | - Abeer Alassaf
- Department of Pediatrics, School of Medicine, University of Jordan, Amman, Jordan
| | - Mary Ann Ugochi Ibekwe
- Department of Pediatrics, Federal Teaching Hospital Abakaliki, Ebonyi State University, Abakaliki, Nigeria
| | | | - Bashir Mukhtar Elwasila Elmahi
- Department of Paediatrics and Child Health, Faculty of Medicine, University of Khartoum, Khartoum, Sudan.,Sudan Childhood Diabetes Center, Khartoum, Sudan
| | - Hanan Mekki
- Department of Paediatrics and Child Health, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Jan Lebl
- Department of Pediatrics, Second Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Mohammed Ahmed Abdullah
- Department of Paediatrics and Child Health, Faculty of Medicine, University of Khartoum, Khartoum, Sudan.,Sudan Childhood Diabetes Center, Khartoum, Sudan
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25
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Bello-Morales R, Andreu S, Ripa I, López-Guerrero JA. HSV-1 and Endogenous Retroviruses as Risk Factors in Demyelination. Int J Mol Sci 2021; 22:ijms22115738. [PMID: 34072259 PMCID: PMC8199333 DOI: 10.3390/ijms22115738] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 12/19/2022] Open
Abstract
Herpes simplex virus type 1 (HSV-1) is a neurotropic alphaherpesvirus that can infect the peripheral and central nervous systems, and it has been implicated in demyelinating and neurodegenerative processes. Transposable elements (TEs) are DNA sequences that can move from one genomic location to another. TEs have been linked to several diseases affecting the central nervous system (CNS), including multiple sclerosis (MS), a demyelinating disease of unknown etiology influenced by genetic and environmental factors. Exogenous viral transactivators may activate certain retrotransposons or class I TEs. In this context, several herpesviruses have been linked to MS, and one of them, HSV-1, might act as a risk factor by mediating processes such as molecular mimicry, remyelination, and activity of endogenous retroviruses (ERVs). Several herpesviruses have been involved in the regulation of human ERVs (HERVs), and HSV-1 in particular can modulate HERVs in cells involved in MS pathogenesis. This review exposes current knowledge about the relationship between HSV-1 and human ERVs, focusing on their contribution as a risk factor for MS.
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Affiliation(s)
- Raquel Bello-Morales
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (S.A.); (I.R.); (J.A.L.-G.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
- Correspondence:
| | - Sabina Andreu
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (S.A.); (I.R.); (J.A.L.-G.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
| | - Inés Ripa
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (S.A.); (I.R.); (J.A.L.-G.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
| | - José Antonio López-Guerrero
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (S.A.); (I.R.); (J.A.L.-G.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
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26
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Gazquez-Gutierrez A, Witteveldt J, R Heras S, Macias S. Sensing of transposable elements by the antiviral innate immune system. RNA (NEW YORK, N.Y.) 2021; 27:rna.078721.121. [PMID: 33888553 PMCID: PMC8208052 DOI: 10.1261/rna.078721.121] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/17/2021] [Indexed: 05/15/2023]
Abstract
Around half of the genome in mammals is composed of transposable elements (TEs) such as DNA transposons and retrotransposons. Several mechanisms have evolved to prevent their activity and the detrimental impact of their insertional mutagenesis. Despite these potentially negative effects, TEs are essential drivers of evolution, and in certain settings, beneficial to their hosts. For instance, TEs have rewired the antiviral gene regulatory network and are required for early embryonic development. However, due to structural similarities between TE-derived and viral nucleic acids, cells can misidentify TEs as invading viruses and trigger the major antiviral innate immune pathway, the type I interferon (IFN) response. This review will focus on the different settings in which the role of TE-mediated IFN activation has been documented, including cancer and senescence. Importantly, TEs may also play a causative role in the development of complex autoimmune diseases characterised by constitutive type I IFN activation. All these observations suggest the presence of strong but opposing forces driving the coevolution of TEs and antiviral defence. A better biological understanding of the TE replicative cycle as well as of the antiviral nucleic acid sensing mechanisms will provide insights into how these two biological processes interact and will help to design better strategies to treat human diseases characterised by aberrant TE expression and/or type I IFN activation.
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Affiliation(s)
| | - Jeroen Witteveldt
- University of Edinburgh - Institute of Immunology and Infection Research
| | - Sara R Heras
- GENYO. Centre for Genomics and Oncological Research, Pfizer University of Granada
| | - Sara Macias
- Institute of Immunology and Infection Research
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27
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Charvet B, Pierquin J, Brunel J, Gorter R, Quétard C, Horvat B, Amor S, Portoukalian J, Perron H. Human Endogenous Retrovirus Type W Envelope from Multiple Sclerosis Demyelinating Lesions Shows Unique Solubility and Antigenic Characteristics. Virol Sin 2021; 36:1006-1026. [PMID: 33770381 PMCID: PMC8558138 DOI: 10.1007/s12250-021-00372-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 02/08/2021] [Indexed: 12/15/2022] Open
Abstract
In multiple sclerosis (MS), human endogenous retrovirus W family (HERV-W) envelope protein, pHERV-W ENV, limits remyelination and induces microglia-mediated neurodegeneration. To better understand its role, we examined the soluble pHERV-W antigen from MS brain lesions detected by specific antibodies. Physico-chemical and antigenic characteristics confirmed differences between pHERV-W ENV and syncytin-1. pHERV-W ENV monomers and trimers remained associated with membranes, while hexamers self-assembled from monomers into a soluble macrostructure involving sulfatides in MS brain. Extracellular hexamers are stabilized by internal hydrophobic bonds and external hydrophilic moieties. HERV-W studies in MS also suggest that this diffusible antigen may correspond to a previously described high-molecular-weight neurotoxic factor secreted by MS B-cells and thus represents a major agonist in MS pathogenesis. Adapted methods are now needed to identify encoding HERV provirus(es) in affected cells DNA. The properties and origin of MS brain pHERV-W ENV soluble antigen will allow a better understanding of the role of HERVs in MS pathogenesis. The present results anyhow pave the way to an accurate detection of the different forms of pHERV-W ENV antigen with appropriate conditions that remained unseen until now.
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Affiliation(s)
- Benjamin Charvet
- GeNeuro Innovation, Lyon, 69008, France. .,CIRI, International Center for Infectiology Research, INSERM U1111, CNRS UMR5308, University of Lyon, ENS Lyon, France. .,Université Claude Bernard Lyon 1, Lyon, 69000, France.
| | | | - Joanna Brunel
- GeNeuro Innovation, Lyon, 69008, France.,CIRI, International Center for Infectiology Research, INSERM U1111, CNRS UMR5308, University of Lyon, ENS Lyon, France.,Université Claude Bernard Lyon 1, Lyon, 69000, France
| | - Rianne Gorter
- Department of Pathology, Amsterdam UMC, Location VUMC, 1007 MB, Amsterdam, The Netherlands
| | | | - Branka Horvat
- CIRI, International Center for Infectiology Research, INSERM U1111, CNRS UMR5308, University of Lyon, ENS Lyon, France.,Université Claude Bernard Lyon 1, Lyon, 69000, France
| | - Sandra Amor
- Department of Pathology, Amsterdam UMC, Location VUMC, 1007 MB, Amsterdam, The Netherlands.,Centre for Neuroscience and Trauma, Blizard Institute, Barts and London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK
| | | | - Hervé Perron
- GeNeuro Innovation, Lyon, 69008, France. .,Université Claude Bernard Lyon 1, Lyon, 69000, France.
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28
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Römer C. Viruses and Endogenous Retroviruses as Roots for Neuroinflammation and Neurodegenerative Diseases. Front Neurosci 2021; 15:648629. [PMID: 33776642 PMCID: PMC7994506 DOI: 10.3389/fnins.2021.648629] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Accepted: 02/05/2021] [Indexed: 12/15/2022] Open
Abstract
Many neurodegenerative diseases are associated with chronic inflammation in the brain and periphery giving rise to a continuous imbalance of immune processes. Next to inflammation markers, activation of transposable elements, including long intrespersed nuclear elements (LINE) elements and endogenous retroviruses (ERVs), has been identified during neurodegenerative disease progression and even correlated with the clinical severity of the disease. ERVs are remnants of viral infections in the human genome acquired during evolution. Upon activation, they produce transcripts and the phylogenetically youngest ones are still able to produce viral-like particles. In addition, ERVs can bind transcription factors and modulate immune response. Being between own and foreign, ERVs are reviewed in the context of viral infections of the central nervous system, in aging and neurodegenerative diseases. Moreover, this review tests the hypothesis that viral infection may be a trigger at the onset of neuroinflammation and that ERVs sustain the inflammatory imbalance by summarizing existing data of neurodegenerative diseases associated with viruses and/or ERVs.
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Affiliation(s)
- Christine Römer
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, The Berlin Institute for Medical Systems Biology, Berlin, Germany
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29
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Chopra S, Myers Z, Sekhon H, Dufour A. The Nerves to Conduct a Multiple Sclerosis Crime Investigation. Int J Mol Sci 2021; 22:2498. [PMID: 33801441 PMCID: PMC7958632 DOI: 10.3390/ijms22052498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/25/2021] [Accepted: 02/25/2021] [Indexed: 12/12/2022] Open
Abstract
Multiple sclerosis (MS) is a chronic inflammatory neurodegenerative autoimmune disease characterized by the aberrant infiltration of immune cells into the central nervous system (CNS) and by the loss of myelin. Sclerotic lesions and various inhibitory factors hamper the remyelination processes within the CNS. MS patients typically experience gradual cognitive and physical disabilities as the disease progresses. The etiology of MS is still unclear and emerging evidence suggests that microbiome composition could play a much more significant role in disease pathogenesis than was initially thought. Initially believed to be isolated to the gut microenvironment, we now know that the microbiome plays a much broader role in various tissues and is essential in the development of the immune system. Here, we present some of the unexpected roles that the microbiome plays in MS and discuss approaches for the development of next-generation treatment strategies.
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Affiliation(s)
- Sameeksha Chopra
- McCaig Institute for Bone and Joint Health, Calgary, AB T2N 4N1, Canada; (S.C.); (Z.M.); (H.S.)
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB T2N 4N1, Canada
- Faculty of Health Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada
| | - Zoë Myers
- McCaig Institute for Bone and Joint Health, Calgary, AB T2N 4N1, Canada; (S.C.); (Z.M.); (H.S.)
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Henna Sekhon
- McCaig Institute for Bone and Joint Health, Calgary, AB T2N 4N1, Canada; (S.C.); (Z.M.); (H.S.)
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Antoine Dufour
- McCaig Institute for Bone and Joint Health, Calgary, AB T2N 4N1, Canada; (S.C.); (Z.M.); (H.S.)
- Department of Physiology and Pharmacology, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB T2N 4N1, Canada
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30
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Gröger V, Emmer A, Staege MS, Cynis H. Endogenous Retroviruses in Nervous System Disorders. Pharmaceuticals (Basel) 2021; 14:ph14010070. [PMID: 33467098 PMCID: PMC7829834 DOI: 10.3390/ph14010070] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 02/06/2023] Open
Abstract
Human endogenous retroviruses (HERV) have been implicated in the pathogenesis of several nervous system disorders including multiple sclerosis and amyotrophic lateral sclerosis. The toxicity of HERV-derived RNAs and proteins for neuronal cells has been demonstrated. The involvement of HERV in the pathogenesis of currently incurable diseases might offer new treatment strategies based on the inhibition of HERV activities by small molecules or therapeutic antibodies.
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Affiliation(s)
- Victoria Gröger
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, 06120 Halle (Saale), Germany;
| | - Alexander Emmer
- Department of Neurology, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany;
| | - Martin S. Staege
- Department of Surgical and Conservative Pediatrics and Adolescent Medicine, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany
- Correspondence: (M.S.S.); (H.C.); Tel.: +49-345-557-7280 (M.S.S.); +49-345-13142835 (H.C.)
| | - Holger Cynis
- Department of Drug Design and Target Validation, Fraunhofer Institute for Cell Therapy and Immunology, 06120 Halle (Saale), Germany;
- Correspondence: (M.S.S.); (H.C.); Tel.: +49-345-557-7280 (M.S.S.); +49-345-13142835 (H.C.)
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31
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Ahmadi A, De Toma I, Vilor-Tejedor N, Eftekhariyan Ghamsari MR, Sadeghi I. Transposable elements in brain health and disease. Ageing Res Rev 2020; 64:101153. [PMID: 32977057 DOI: 10.1016/j.arr.2020.101153] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 07/22/2020] [Accepted: 08/19/2020] [Indexed: 12/17/2022]
Abstract
Transposable elements (TEs) occupy a large fraction of the human genome but only a small proportion of these elements are still active today. Recent works have suggested that TEs are expressed and active in the brain, challenging the dogma that neuronal genomes are static and revealing that they are susceptible to somatic genomic alterations. These new findings have major implications for understanding the neuroplasticity of the brain, which could hypothetically have a role in behavior and cognition, and contribute to vulnerability to disease. As active TEs could induce genetic diversity and mutagenesis, their influences on human brain development and diseases are of great interest. In this review, we will focus on the active TEs in the human genome and discuss in detail their impacts on human brain development. Furthermore, the association between TEs and brain-related diseases is discussed.
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32
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The Role of Extracellular Vesicles in Demyelination of the Central Nervous System. Int J Mol Sci 2020; 21:ijms21239111. [PMID: 33266211 PMCID: PMC7729475 DOI: 10.3390/ijms21239111] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/27/2020] [Accepted: 11/28/2020] [Indexed: 12/21/2022] Open
Abstract
It is being increasingly demonstrated that extracellular vesicles (EVs) are deeply involved in the physiology of the central nervous system (CNS). Processes such as synaptic activity, neuron-glia communication, myelination and immune response are modulated by EVs. Likewise, these vesicles may participate in many pathological processes, both as triggers of disease or, on the contrary, as mechanisms of repair. EVs play relevant roles in neurodegenerative disorders such as Alzheimer’s or Parkinson’s diseases, in viral infections of the CNS and in demyelinating pathologies such as multiple sclerosis (MS). This review describes the involvement of these membrane vesicles in major demyelinating diseases, including MS, neuromyelitis optica, progressive multifocal leukoencephalopathy and demyelination associated to herpesviruses.
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33
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Evans TA, Erwin JA. Retroelement-derived RNA and its role in the brain. Semin Cell Dev Biol 2020; 114:68-80. [PMID: 33229216 DOI: 10.1016/j.semcdb.2020.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 10/20/2020] [Accepted: 11/04/2020] [Indexed: 12/17/2022]
Abstract
Comprising ~40% of the human genome, retroelements are mobile genetic elements which are transcribed into RNA, then reverse-transcribed into DNA and inserted into a new site in the genome. Retroelements are referred to as "genetic parasites", residing among host genes and relying on host machinery for transcription and evolutionary propagation. The healthy brain has the highest expression of retroelement-derived sequences compared to other somatic tissue, which leads to the question: how does retroelement-derived RNA influence human traits and cellular states? While the functional importance of upregulating retroelement expression in the brain is an active area of research, RNA species derived from retroelements influence both self- and host gene expression by contributing to chromatin remodeling, alternative splicing, somatic mosaicism and translational repression. Here, we review the emerging evidence that the functional importance of RNA derived from retroelements is multifaceted. Retroelements can influence organismal states through the seeding of epigenetic states in chromatin, the production of structured RNA and even catalytically active ribozymes, the generation of cytoplasmic ssDNA and RNA/DNA hybrids, the production of viral-like proteins, and the generation of somatic mutations. Comparative sequencing suggests that retroelements can contribute to intraspecies variation through these mechanisms to alter transcript identity and abundance. In humans, an increasing number of neurodevelopmental and neurodegenerative conditions are associated with dysregulated retroelements, including Aicardi-Goutieres syndrome (AGS), Rett syndrome (RTT), Amyotrophic Lateral Sclerosis (ALS), Alzheimer's disease (AD), multiple sclerosis (MS), schizophrenia (SZ), and aging. Taken together, these concepts suggest a larger functional role for RNA derived from retroelements. This review aims to define retroelement-derived RNA, discuss how it impacts the mammalian genome, as well as summarize data supporting phenotypic consequences of this unique RNA subset in the brain.
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Affiliation(s)
- Taylor A Evans
- Lieber Institute for Brain Development, Baltimore, MD, USA; Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Jennifer Ann Erwin
- Lieber Institute for Brain Development, Baltimore, MD, USA; Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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34
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Bello-Morales R, Andreu S, López-Guerrero JA. The Role of Herpes Simplex Virus Type 1 Infection in Demyelination of the Central Nervous System. Int J Mol Sci 2020; 21:ijms21145026. [PMID: 32708697 PMCID: PMC7404202 DOI: 10.3390/ijms21145026] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 12/13/2022] Open
Abstract
Herpes simplex type 1 (HSV-1) is a neurotropic virus that infects the peripheral and central nervous systems. After primary infection in epithelial cells, HSV-1 spreads retrogradely to the peripheral nervous system (PNS), where it establishes a latent infection in the trigeminal ganglia (TG). The virus can reactivate from the latent state, traveling anterogradely along the axon and replicating in the local surrounding tissue. Occasionally, HSV-1 may spread trans-synaptically from the TG to the brainstem, from where it may disseminate to higher areas of the central nervous system (CNS). It is not completely understood how HSV-1 reaches the CNS, although the most accepted idea is retrograde transport through the trigeminal or olfactory tracts. Once in the CNS, HSV-1 may induce demyelination, either as a direct trigger or as a risk factor, modulating processes such as remyelination, regulation of endogenous retroviruses, or molecular mimicry. In this review, we describe the current knowledge about the involvement of HSV-1 in demyelination, describing the pathways used by this herpesvirus to spread throughout the CNS and discussing the data that suggest its implication in demyelinating processes.
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Affiliation(s)
- Raquel Bello-Morales
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (S.A.); (J.A.L.-G.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
- Correspondence:
| | - Sabina Andreu
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (S.A.); (J.A.L.-G.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
| | - José Antonio López-Guerrero
- Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (S.A.); (J.A.L.-G.)
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, 28049 Madrid, Spain
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35
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Lathe R, St Clair D. From conifers to cognition: Microbes, brain and behavior. GENES BRAIN AND BEHAVIOR 2020; 19:e12680. [PMID: 32515128 DOI: 10.1111/gbb.12680] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 05/12/2020] [Accepted: 05/29/2020] [Indexed: 12/25/2022]
Abstract
A diversity of bacteria, protozoans and viruses ("endozoites") were recently uncovered within healthy tissues including the human brain. By contrast, it was already recognized a century ago that healthy plants tissues contain abundant endogenous microbes ("endophytes"). Taking endophytes as an informative precedent, we overview the nature, prevalence, and role of endozoites in mammalian tissues, centrally focusing on the brain, concluding that endozoites are ubiquitous in diverse tissues. These passengers often remain subclinical, but they are not silent. We address their routes of entry, mechanisms of persistence, tissue specificity, and potential to cause long-term behavioral changes and/or immunosuppression in mammals, where rabies virus is the exemplar. We extend the discussion to Herpesviridae, Coronaviridae, and Toxoplasma, as well as to diverse bacteria and yeasts, and debate the advantages and disadvantages that endozoite infection might afford to the host and to the ecosystem. We provide a clinical perspective in which endozoites are implicated in neurodegenerative disease, anxiety/depression, and schizophrenia. We conclude that endozoites are instrumental in the delicate balance between health and disease, including age-related brain disease, and that endozoites have played an important role in the evolution of brain function and human behavior.
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Affiliation(s)
- Richard Lathe
- Division of Infection Medicine, University of Edinburgh Medical School, Edinburgh, UK
| | - David St Clair
- Institute of Medical Sciences, School of Medicine, University of Aberdeen, Aberdeen, UK
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36
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Tarlinton RE, Martynova E, Rizvanov AA, Khaiboullina S, Verma S. Role of Viruses in the Pathogenesis of Multiple Sclerosis. Viruses 2020; 12:E643. [PMID: 32545816 PMCID: PMC7354629 DOI: 10.3390/v12060643] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/07/2020] [Accepted: 06/10/2020] [Indexed: 12/17/2022] Open
Abstract
Multiple sclerosis (MS) is an immune inflammatory disease, where the underlying etiological cause remains elusive. Multiple triggering factors have been suggested, including environmental, genetic and gender components. However, underlying infectious triggers to the disease are also suspected. There is an increasing abundance of evidence supporting a viral etiology to MS, including the efficacy of interferon therapy and over-detection of viral antibodies and nucleic acids when compared with healthy patients. Several viruses have been proposed as potential triggering agents, including Epstein-Barr virus, human herpesvirus 6, varicella-zoster virus, cytomegalovirus, John Cunningham virus and human endogenous retroviruses. These viruses are all near ubiquitous and have a high prevalence in adult populations (or in the case of the retroviruses are actually part of the genome). They can establish lifelong infections with periods of reactivation, which may be linked to the relapsing nature of MS. In this review, the evidence for a role for viral infection in MS will be discussed with an emphasis on immune system activation related to MS disease pathogenesis.
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Affiliation(s)
- Rachael E. Tarlinton
- School of Veterinary Medicine and Science, University of Nottingham, Loughborough LE12 5RD, UK;
| | - Ekaterina Martynova
- Insititute of Fundamental Medicine and Biology Kazan Federal University, 420008 Kazan, Russia; (E.M.); (A.A.R.)
| | - Albert A. Rizvanov
- Insititute of Fundamental Medicine and Biology Kazan Federal University, 420008 Kazan, Russia; (E.M.); (A.A.R.)
| | | | - Subhash Verma
- School of Medicine, University of Nevada, Reno, NV 89557, USA;
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Silverstein SM, Demmin DL, Schallek JB, Fradkin SI. Measures of Retinal Structure and Function as Biomarkers in Neurology and Psychiatry. Biomark Neuropsychiatry 2020. [DOI: 10.1016/j.bionps.2020.100018] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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38
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Talotta R, Atzeni F, Laska MJ. Retroviruses in the pathogenesis of systemic lupus erythematosus: Are they potential therapeutic targets? Autoimmunity 2020; 53:177-191. [PMID: 32321325 DOI: 10.1080/08916934.2020.1755962] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The pathogenesis of systemic lupus erythematosus (SLE) is characterised by the hyper-activation of immunologic pathways related to the antiviral response. Exogenous and endogenous retroviruses, by integrating their DNA templates in the host cell genome, may epigenetically control the transcription of genes involved in the immune response. Furthermore, their nucleic acids or neo-synthesized proteins could stimulate the sensor molecules placed upstream the inflammatory cascade. Exogenous retroviruses, like human immunodeficiency virus, have been associated to SLE-like manifestations or to a fair SLE diagnosis. In addition, there is some evidence confirming a pathogenic role of human endogenous retroviruses in SLE. In line with these data, the use of antiretroviral agents could represent an attractive opportunity in the future therapeutic algorithms of this disease, but studies are still missing.
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Affiliation(s)
- Rossella Talotta
- Rheumatology Unit, Department of Clinical and Experimental Medicine, University Hospital "Gaetano Martino", Messina, Italy
| | - Fabiola Atzeni
- Rheumatology Unit, Department of Clinical and Experimental Medicine, University Hospital "Gaetano Martino", Messina, Italy
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Abstract
The etiology and pathogenesis of MS is likely to involve multiple factors interacting with each other, and the role of infectious and viral agents is still under debate, however a consistent amount of studies suggests that some viruses are associated with the disease. The strongest documentation has come from the detection of viral nucleic acid or antigen or of an anti-viral antibody response in MS patients. A further step for the study of the mechanism viruses might be involved in can be made using in vitro and in vivo models. While in vitro models, based on glial and neural cell lines from various sources are widely used, in vivo animal models present challenges. Indeed neurotropic animal viruses are currently used to study demyelination in well-established models, but animal models of demyelination by human virus infection have only recently been developed, using animal gammaherpesviruses closely related to Epstein Barr virus (EBV), or using marmosets expressing the specific viral receptor for Human Herpesvirus 6 (HHV-6). The present review will illustrate the main potential mechanisms of MS pathogenesis possibly associated with viral infections and viruses currently used to study demyelination in animal models. Then the viruses most strongly linked with MS will be discussed, in the perspective that more than one virus might have a role, with varying degrees of interaction, contributing to MS heterogeneity.
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Affiliation(s)
- Donatella Donati
- Neurologia e Neurofisiologia Clinica, Azienda Ospedaliera Universitaria Senese I 53100 Siena, Italy
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40
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Ovejero T, Sadones O, Sánchez-Fito T, Almenar-Pérez E, Espejo JA, Martín-Martínez E, Nathanson L, Oltra E. Activation of Transposable Elements in Immune Cells of Fibromyalgia Patients. Int J Mol Sci 2020; 21:E1366. [PMID: 32085571 PMCID: PMC7072917 DOI: 10.3390/ijms21041366] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 02/06/2020] [Accepted: 02/14/2020] [Indexed: 02/07/2023] Open
Abstract
Advancements in nucleic acid sequencing technology combined with an unprecedented availability of metadata have revealed that 45% of the human genome constituted by transposable elements (TEs) is not only transcriptionally active but also physiologically necessary. Dysregulation of TEs, including human retroviral endogenous sequences (HERVs) has been shown to associate with several neurologic and autoimmune diseases, including Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). However, no study has yet addressed whether abnormal expression of these sequences correlates with fibromyalgia (FM), a disease frequently comorbid with ME/CFS. The work presented here shows, for the first time, that, in fact, HERVs of the H, K and W types are overexpressed in immune cells of FM patients with or without comorbid ME/CFS. Patients with increased HERV expression (N = 14) presented increased levels of interferon (INF-β and INF-γ) but unchanged levels of TNF-α. The findings reported in this study could explain the flu-like symptoms FM patients present with in clinical practice, in the absence of concomitant infections. Future work aimed at identifying specific genomic loci differentially affected in FM and/or ME/CFS is warranted.
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Affiliation(s)
- Tamara Ovejero
- School of Medicine, Universidad Católica de Valencia San Vicente Mártir, 46001 Valencia, Spain;
| | | | - Teresa Sánchez-Fito
- Escuela de Doctorado, Universidad Católica de Valencia San Vicente Mártir, 46008 Valencia, Spain; (T.S.-F.); (E.A.-P.)
| | - Eloy Almenar-Pérez
- Escuela de Doctorado, Universidad Católica de Valencia San Vicente Mártir, 46008 Valencia, Spain; (T.S.-F.); (E.A.-P.)
| | - José Andrés Espejo
- School of Biotechnology, Universidad Católica de Valencia San Vicente Mártir, 46001 Valencia, Spain;
| | | | - Lubov Nathanson
- Institute for Neuro Immune Medicine, Nova Southeastern University, Ft Lauderdale, FL 33314, USA;
| | - Elisa Oltra
- School of Medicine, Universidad Católica de Valencia San Vicente Mártir, 46001 Valencia, Spain;
- Centro de Investigación Traslacional San Alberto Magno, Universidad Católica de Valencia San Vicente Mártir, 46001 Valencia, Spain
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41
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Tarlinton R, Wang B, Morandi E, Gran B, Khaiboullin T, Martynova E, Rizvanov A, Khaiboullina S. Differential Expression of HERV-W in Peripheral Blood in Multiple Sclerosis and Healthy Patients in Two Different Ethnic Groups. Front Pharmacol 2020; 10:1645. [PMID: 32076404 PMCID: PMC7002920 DOI: 10.3389/fphar.2019.01645] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 12/16/2019] [Indexed: 12/17/2022] Open
Abstract
Overexpression of the Human endogenous retrovirus W (HERV-W) group of inherited retroviruses has been consistently linked with Multiple Sclerosis (MS). However most of the studies on this link have focused on European genetic groups with a very high risk of MS and it is not clear that this relationship holds for all ethnic groups. This study examined via qPCR the RNA expression in peripheral blood of HERV-W (the multiple sclerosis associated retrovirus variant MSRV) of MS patients and healthy controls from two ethnic groups with very different risk rates of MS. Population one was derived from the UK with a Northern European genetic background and an MS risk rate of 108/100,000, population two was derived from the republic of Tatarstan, Russian Federation, with a mixed Russian (Eastern European) and Tartar (Turkic or Volga/Urals) population with an MS risk rate of 21-31/100,000. The Russian population displayed a significantly higher basal level of expression of MSRV in both healthy and MS individuals when compared to the British control population with a trend in the Russian population towards higher expression levels in MS patients than healthy patients.
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Affiliation(s)
- Rachael Tarlinton
- School of Veterinary Medicine and Science, University of Nottingham, Loughborough, United Kingdom
| | - Belinda Wang
- School of Veterinary Medicine and Science, University of Nottingham, Loughborough, United Kingdom
| | - Elena Morandi
- Centre de Physiopathologie de Toulouse Purpan (CPTP), Université de Toulouse, UPS, INSERM, CNRS, Toulouse, France
| | - Bruno Gran
- Clinical Neurology Research Group, Division of Clinical Neuroscience, University of Nottingham School of Medicine, Nottingham, United Kingdom
| | - Timur Khaiboullin
- Republican Research and Clinical Center of Neurology and Neurosurgery, Kazan, Russia
| | - Ekatarina Martynova
- Insitute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Albert Rizvanov
- Insitute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Svetlana Khaiboullina
- Insitute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia.,Department of Microbiology and Immunology, University of Nevada, Reno, NV, United States
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42
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Jakimovski D, Weinstock-Guttman B, Ramanathan M, Dwyer MG, Zivadinov R. Infections, Vaccines and Autoimmunity: A Multiple Sclerosis Perspective. Vaccines (Basel) 2020; 8:vaccines8010050. [PMID: 32012815 PMCID: PMC7157658 DOI: 10.3390/vaccines8010050] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 01/21/2020] [Accepted: 01/24/2020] [Indexed: 12/13/2022] Open
Abstract
Background: Multiple sclerosis (MS) is a chronic neuroinflammatory and neurodegenerative disease that is associated with multiple environmental factors. Among suspected susceptibility events, studies have questioned the potential role of overt viral and bacterial infections, including the Epstein Bar virus (EBV) and human endogenous retroviruses (HERV). Furthermore, the fast development of immunomodulatory therapies further questions the efficacy of the standard immunization policies in MS patients. Topics reviewed: This narrative review will discuss the potential interplay between viral and bacterial infections and their treatment on MS susceptibility and disease progression. In addition, the review specifically discusses the interactions between MS pathophysiology and vaccination for hepatitis B, influenza, human papillomavirus, diphtheria, pertussis, and tetanus (DTP), and Bacillus Calmette-Guerin (BCG). Data regarding potential interaction between MS disease modifying treatment (DMT) and vaccine effectiveness is also reviewed. Moreover, HERV-targeted therapies such as GNbAC1 (temelimab), EBV-based vaccines for treatment of MS, and the current state regarding the development of T-cell and DNA vaccination are discussed. Lastly, a reviewing commentary on the recent 2019 American Academy of Neurology (AAN) practice recommendations regarding immunization and vaccine-preventable infections in the settings of MS is provided. Conclusion: There is currently no sufficient evidence to support associations between standard vaccination policies and increased risk of MS. MS patients treated with immunomodulatory therapies may have a lower benefit from viral and bacterial vaccination. Despite their historical underperformance, new efforts in creating MS-based vaccines are currently ongoing. MS vaccination programs follow the set back and slow recovery which is widely seen in other fields of medicine.
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Affiliation(s)
- Dejan Jakimovski
- Buffalo Neuroimaging Analysis Center, Department of Neurology, University at Buffalo, State University of New York, Buffalo, NY 14203, USA
- Correspondence:
| | - Bianca Weinstock-Guttman
- Jacobs MS Center, Department of Neurology, University at Buffalo, State University of New York, Buffalo, NY 14203, USA
| | - Murali Ramanathan
- School of Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, NY 14214, USA
| | - Michael G. Dwyer
- Buffalo Neuroimaging Analysis Center, Department of Neurology, University at Buffalo, State University of New York, Buffalo, NY 14203, USA
| | - Robert Zivadinov
- Buffalo Neuroimaging Analysis Center, Department of Neurology, University at Buffalo, State University of New York, Buffalo, NY 14203, USA
- Center for Biomedical Imaging at Clinical Translational Science Institute, University at Buffalo, State University of New York, Buffalo, NY 14203, USA
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43
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Abstract
PURPOSE OF THE REVIEW The aim of this review is to discuss recent data pointing at an involvement of human endogenous retroviruses (HERVs) in type 1 diabetes (T1D) onset and progression. RECENT FINDINGS The envelope protein of HERV-W family, named HERV-W-Env, was detected in pancreata from T1D patients and was shown to display pro-inflammatory properties and direct toxicity toward pancreatic beta cells. The etiopathogenesis of T1D remains elusive, even if conventional environmental viral infections have been recurrently involved. Nonetheless, a new category of pathogens may provide the missing link between genetic susceptibility and environmental factors long thought to contribute to T1D onset. A number of studies have now shown that HERV sequences, which are normally inactivated or repressed in the human genome, could be activated by environmental viruses. Thus, if similarly activated by viruses associated with T1D, disregarded HERV genes may underlie T1D genetic susceptibility. Moreover, once expressed, HERV elements may display broad pathogenic properties, which identify them as potential new therapeutic targets.
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Affiliation(s)
- Sandrine Levet
- GeNeuro Innovation, 60 avenue Rockefeller, 69008 Lyon, France
| | - B. Charvet
- GeNeuro Innovation, 60 avenue Rockefeller, 69008 Lyon, France
| | - A. Bertin
- Faculté de Médecine, CHU Lille, Laboratoire de Virologie EA3610, Université Lille, F-59000 Lille, France
| | - A. Deschaumes
- Faculté de Médecine, CHU Lille, Laboratoire de Virologie EA3610, Université Lille, F-59000 Lille, France
| | - H. Perron
- GeNeuro Innovation, 60 avenue Rockefeller, 69008 Lyon, France
- Laboratoire des déficits immunitaires, University of Lyon, Lyon, France
- Plan-les-Ouates, GeNeuro SA, Geneva, Switzerland
| | - D. Hober
- Faculté de Médecine, CHU Lille, Laboratoire de Virologie EA3610, Université Lille, F-59000 Lille, France
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44
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Rodrigues LS, da Silva Nali LH, Leal COD, Sabino EC, Lacerda EM, Kingdon CC, Nacul L, Romano CM. HERV-K and HERV-W transcriptional activity in myalgic encephalomyelitis/chronic fatigue syndrome. AUTOIMMUNITY HIGHLIGHTS 2019; 10:12. [PMID: 32257068 PMCID: PMC7065355 DOI: 10.1186/s13317-019-0122-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 10/09/2019] [Indexed: 02/08/2023]
Abstract
Background Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/MS) is an incapacitating chronic disease that dramatically compromise the life quality. The CFS/ME pathogenesis is multifactorial, and it is believed that immunological, metabolic and environmental factors play a role. It is well documented an increased activity of Human endogenous retroviruses (HERVs) from different families in autoimmune and neurological diseases, making these elements good candidates for biomarkers or even triggers for such diseases. Methods Here the expression of Endogenous retroviruses K and W (HERV-K and HERV-W) was determined in blood from moderately and severely affected ME/CFS patients through real time PCR. Results HERV-K was overexpressed only in moderately affected individuals but HERV-W showed no difference. Conclusions This is the first report about HERV-K differential expression in moderate ME/CFS. Although the relationship between HERVs and ME/CFS has yet to be proven, the observation of this phenomenon deserves further attention.
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Affiliation(s)
- Lucas S Rodrigues
- 1Laboratório de Virologia, Instituto de Medicina Tropical de São Paulo, Universidade de São Paulo, Rua Dr. Enéas de Carvalho Aguiar, 470, São Paulo, SP 05403-000 Brazil
| | - Luiz H da Silva Nali
- 1Laboratório de Virologia, Instituto de Medicina Tropical de São Paulo, Universidade de São Paulo, Rua Dr. Enéas de Carvalho Aguiar, 470, São Paulo, SP 05403-000 Brazil.,2Pós-Graduação em Ciências da Saúde, Universidade Santo Amaro, São Paulo, Brazil
| | - Cibele O D Leal
- 1Laboratório de Virologia, Instituto de Medicina Tropical de São Paulo, Universidade de São Paulo, Rua Dr. Enéas de Carvalho Aguiar, 470, São Paulo, SP 05403-000 Brazil
| | - Ester C Sabino
- 1Laboratório de Virologia, Instituto de Medicina Tropical de São Paulo, Universidade de São Paulo, Rua Dr. Enéas de Carvalho Aguiar, 470, São Paulo, SP 05403-000 Brazil.,3Departamento de Moléstias Infecciosas e Parasitárias, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Eliana M Lacerda
- 4Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Caroline C Kingdon
- 4Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Luis Nacul
- 4Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Camila M Romano
- 1Laboratório de Virologia, Instituto de Medicina Tropical de São Paulo, Universidade de São Paulo, Rua Dr. Enéas de Carvalho Aguiar, 470, São Paulo, SP 05403-000 Brazil.,5Hospital das Clinicas HCFMUSP (LIM52), Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
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45
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Talotta R, Sarzi-Puttini P, Laska MJ, Atzeni F. Retrotransposons shuttling genetic and epigenetic information from the nuclear to the mitochondrial compartment: Do they play a pathogenetic role in scleroderma? Cytokine Growth Factor Rev 2019; 49:42-58. [PMID: 31677967 DOI: 10.1016/j.cytogfr.2019.10.001] [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: 07/11/2019] [Revised: 10/09/2019] [Accepted: 10/10/2019] [Indexed: 10/25/2022]
Abstract
Endogenous retroelements are a class of ancient defective viral insertions contained in the genome of host cells, where they account for up to 40% of all DNA. Centuries of co-existence in host genome have led to the development of immunotolerance to endogenous retroelements, most of which are defective and unable to replicate or transcribe functional proteins. However, given their capacity to move across the nuclear and mitochondrial genome and recombine, they could mix phenotypes and give rise to infections that may trigger innate and adaptive immune responses by sensing receptors capable of recognising foreign nucleic acids and proteins. It has recently been suggested that they play a role in the pathogenesis of autoimmune diseases on the grounds of their partial reactivation or the epigenetic control of host gene transcription. A number of studies have confirmed their contribution to the development of rheumatoid arthritis, multiple sclerosis and systemic lupus erythematosus, but there is still a lack of data concerning systemic sclerosis (SSc). Their role in the pathogenesis of SSc can be hypothesised on the basis of mitochondrial and nuclear chromatinic damage, and hyper-activation of the immune pathway involved in antiviral defense. SSc is characterised by genetic and immunological evidence of a viral infection but, as no viral agent has yet been isolated from SSc patients, the hypothesis that partial reactivation of endogenous retroviruses may trigger the disease cannot be excluded and deserves further investigation.
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Affiliation(s)
- Rossella Talotta
- Rheumatology Unit, University of Messina, Azienda Ospedaliera Gaetano Martino, Via Consolare Valeria 1, 98100 Messina, Italy.
| | - Piercarlo Sarzi-Puttini
- Rheumatology Unit, University Hospital ASST-Fatebenefratelli-Sacco, Via G.B Grassi 74, 20157 Milan, Italy.
| | | | - Fabiola Atzeni
- Rheumatology Unit, University of Messina, Azienda Ospedaliera Gaetano Martino, Via Consolare Valeria 1, 98100 Messina, Italy.
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46
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Milo R, Korczyn AD, Manouchehri N, Stüve O. The temporal and causal relationship between inflammation and neurodegeneration in multiple sclerosis. Mult Scler 2019; 26:876-886. [PMID: 31682184 DOI: 10.1177/1352458519886943] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
It is currently incompletely understood whether inflammation and neurodegeneration are causally related in multiple sclerosis (MS). The sequence of a potential causal relationship is also unknown. Inflammation is present in rather all clinical stages of MS. Its role in the pathogenesis of MS is supported by histopathological analyses, genetic data, and numerous animal models of MS. All approved disease-modifying therapies that reduce clinical relapses and diminish the accumulation of lesions on neuroimaging are anti-inflammatory. Axonal loss and accelerated brain volume loss can also be detected from clinical disease onset throughout all stages. The expression of neurofilament light chain in cerebrospinal fluid and serum, a scaffolding protein in axons and dendrites, is a biomarker of neuronal injury associated with clinical relapses and reflects neuronal loss during episodes of acute inflammation. The recent association of human endogenous retrovirus (HERV) and its envelope proteins with MS illustrates a pathogenic pathway that causally links central nervous system (CNS)-intrinsic proinflammatory effects and inhibition of myelin repair and neuroregeneration. A review of current data on the causal relationship between inflammation and neurodegeneration in MS identified numerous plausible pathomechanisms that link the two events. Observations from most experimental models appear to favor a pathogenesis in which inflammation precedes neurodegeneration.
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Affiliation(s)
- Ron Milo
- Department of Neurology, Barzilai Medical Center, Ashkelon, Israel/Faculty of Health Sciences, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Amos D Korczyn
- Department of Neurology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Navid Manouchehri
- Department of Neurology and Neurotherapeutics, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Olaf Stüve
- Department of Neurology and Neurotherapeutics, The University of Texas Southwestern Medical Center, Dallas, TX, USA/Neurology Section, Medical Service, VA North Texas Health Care System, Dallas, TX, USA/Department of Neurology, Klinikum rechts der Isar, Technische Universität München, München, Germany
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47
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Canli T. A model of human endogenous retrovirus (HERV) activation in mental health and illness. Med Hypotheses 2019; 133:109404. [PMID: 31557593 DOI: 10.1016/j.mehy.2019.109404] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 09/18/2019] [Indexed: 01/04/2023]
Abstract
Despite strong evidence for the heritability of major depressive disorder (MDD), efforts to identify causal genes have been disappointing. Furthermore, although there is strong support for life stress as a major predictor of MDD, there are also considerable individual differences in susceptibility and resilience that remain poorly understood. Efforts to identify specific gene-by-environment risk factors produced results that were initially encouraging, but that were not supported by later large-scale studies. Here I propose a novel mechanism that could address the "missing heritability" of MDD, the role of environmental risk factors, and individual differences in susceptibility and resilience. This mechanism focuses on a class of transposable elements, Human Endogenous Retroviruses (HERVs), which make up approximately 8% of the human genome as the result of ancient retroviral infections that entered mammalian germ lines throughout the course of evolution. My primary hypothesis is that exposure to either exogenous viruses or traumatic experiences can activate HERVs in the brain to cause depressive (and possibly other psychiatric) symptoms. My secondary hypothesis is that individual differences in vulnerability or resilience result from the balance of activated HERVs with pathogenic versus protective functions in the brain. Future research can test these hypotheses by analysis of postmortem human brain tissue from donors with known viral or trauma histories; animal studies manipulating HERV expression; cell culture studies examining regulatory mechanisms of HERV expression; and from brain imaging studies of individuals with known HERV-expression. Such research may reveal novel functions of HERVs in neural tissue and may lead to a new generation of psychiatric interventions designed to target aberrant HERV activation.
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MESH Headings
- Animals
- Brain/virology
- Cells, Cultured
- Cytokines/physiology
- Depressive Disorder, Major/etiology
- Depressive Disorder, Major/genetics
- Depressive Disorder, Major/immunology
- Depressive Disorder, Major/virology
- Disease Models, Animal
- Endogenous Retroviruses/genetics
- Endogenous Retroviruses/physiology
- Environmental Exposure
- Epigenesis, Genetic
- Gene Expression Regulation, Viral
- Gene-Environment Interaction
- Genes, Viral
- Humans
- Intercellular Signaling Peptides and Proteins/physiology
- Mice, Transgenic
- Models, Biological
- Models, Psychological
- Schizophrenia/pathology
- Schizophrenia/virology
- Stress, Psychological
- Terminal Repeat Sequences/genetics
- Virus Activation
- Virus Diseases/complications
- Virus Diseases/psychology
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Affiliation(s)
- Turhan Canli
- Departments of Psychology and Psychiatry, Stony Brook University, Stony Brook, NY 11794-2500, USA.
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48
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Karimi A, Esmaili N, Ranjkesh M, Zolfaghari MA. Expression of human endogenous retroviruses in pemphigus vulgaris patients. Mol Biol Rep 2019; 46:6181-6186. [PMID: 31473891 DOI: 10.1007/s11033-019-05053-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 08/28/2019] [Indexed: 01/09/2023]
Abstract
Pemphigus is a severe, potentially life-threatening autoimmune blistering mucocutaneous disease which establishes with autoreactive IgG antibodies that target cellular adhesions, precisely extracellular domains of keratinocyte proteins. Several genetic and environmental elements are believed to contribute to the pathogenesis of the disease. The extent to which the initiation and progress of this autoimmune blistering disease may be influenced by the expression of human endogenous retroviruses (HERVs) remains to be elucidated. In this study, we evaluated the expression of HERV groups (K, W, and H) in pemphigus vulgaris (PV) patients in comparison to controls. Peripheral blood samples were collected from 24 PV patients and the corresponding age- and sex-matched healthy controls to extract total RNA for evaluation of HERV-K (HML-2), HERV-W, and HERV-H, env gene expression profile by qPCR. The mRNA expression level of HERV-K, HERV-W, and HERV-H were significantly upregulated in PV patients in comparison to healthy controls (P < 0.0001). The difference in expression of studied HERVs groups between men and women was no significant (P > 0.05). Although rituximab taking patients had a decreased expression level of studied HERVs, the results were not significant (P > 0.05). According to our obtained data, HERVs expression could be measured as a possible diagnostic tool for detection of PV and monitoring of the treatment.
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Affiliation(s)
- Abbas Karimi
- Autoimmune Bullous Diseases Research Center, Tehran University of Medical Sciences, Razi Hospital, Tehran, Iran.
- Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Nafiseh Esmaili
- Autoimmune Bullous Diseases Research Center, Tehran University of Medical Sciences, Razi Hospital, Tehran, Iran.
| | - Mohammadreza Ranjkesh
- Department of Dermatology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Ali Zolfaghari
- Department of Molecular Medicine, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
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49
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Human immunodeficiency virus and multiple sclerosis: a review of the literature. Neurol Res Pract 2019; 1:24. [PMID: 33324890 PMCID: PMC7650072 DOI: 10.1186/s42466-019-0030-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 06/06/2019] [Indexed: 01/22/2023] Open
Abstract
Multiple sclerosis (MS) and human immunodeficiency virus (HIV) infection are frequent and well-studied nosological entities. Yet, comorbidity of MS and HIV has only been rarely reported in the medical literature. We conducted a literature search using the databases PubMed, Ovid and Google Scholar, with the aim of identifying published studies and reports concerning HIV and MS. Recent epidemiological studies indicated a negative association between MS and HIV in terms of a reduced risk of developing MS in HIV positive patients. Accumulating clinical evidence additionally suggests a possibly reduced relapse rate of MS in HIV patients. Nevertheless, it remains currently unclear whether this observed inverse correlation could be due to the HIV infection itself, HIV treatment or the combination of both. Among the limited cases of MS in HIV infected patients, MS occurrence was mainly reported during acute HIV infection or during HIV seroconversion. This finding is in line with reports of HIV-related autoimmune disorders, which also occur in early phases of HIV disease. Beneficial effects of antiretroviral therapy on MS activity were reported in few clinical cases. Yet, the single phase II clinical trial (INSPIRE), which investigated the effects of antiretroviral medication (using the integrase inhibitor raltegravir) in patients with relapsing-remitting MS, failed to corroborate any beneficial effects at group level. Nevertheless, recently published experimental evidence suggests that HIV treatments may hold therapeutic potential for MS treatment. Thus, further studies are warranted to firstly, delineate the immunological mechanisms underlying possible efficacy of HIV treatments in MS, and to secondly, assess whether repurposing of HIV drugs for MS could be a worthwhile future research objective.
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50
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Saleh A, Macia A, Muotri AR. Transposable Elements, Inflammation, and Neurological Disease. Front Neurol 2019; 10:894. [PMID: 31481926 PMCID: PMC6710400 DOI: 10.3389/fneur.2019.00894] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 08/02/2019] [Indexed: 12/13/2022] Open
Abstract
Transposable Elements (TE) are mobile DNA elements that can replicate and insert themselves into different locations within the host genome. Their propensity to self-propagate has a myriad of consequences and yet their biological significance is not well-understood. Indeed, retrotransposons have evaded evolutionary attempts at repression and may contribute to somatic mosaicism. Retrotransposons are emerging as potent regulatory elements within the human genome. In the diseased state, there is mounting evidence that endogenous retroelements play a role in etiopathogenesis of inflammatory diseases, with a disposition for both autoimmune and neurological disorders. We postulate that active mobile genetic elements contribute more to human disease pathogenesis than previously thought.
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Affiliation(s)
- Aurian Saleh
- Department of Pediatrics, Rady Children's Hospital San Diego, University of California, San Diego, San Diego, CA, United States
| | - Angela Macia
- Department of Pediatrics, Rady Children's Hospital San Diego, University of California, San Diego, San Diego, CA, United States
| | - Alysson R Muotri
- Department of Pediatrics, Rady Children's Hospital San Diego, University of California, San Diego, San Diego, CA, United States
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