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Chen CC, Howie J, Ebrahimi M, Teymouri K, Woo JJ, Tiwari AK, Zai CC, Kennedy JL. Analysis of the complement component C4 gene with schizophrenia subphenotypes. Schizophr Res 2024; 271:309-318. [PMID: 39084106 DOI: 10.1016/j.schres.2024.07.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 07/15/2024] [Accepted: 07/17/2024] [Indexed: 08/02/2024]
Abstract
BACKGROUND The complement component C4 gene has been identified as a strong marker for schizophrenia (SCZ) risk. The C4 gene has a complex genetic structure consisting of variable structural elements (C4A, C4B, C4L, and C4S) and compound structural forms (C4AL, C4BL, C4AS and C4BS). In addition, the variations in C4 structural forms may have a direct or indirect effect on the brain expression level of C4A and C4B proteins. Previous studies have associated C4AL with higher brain C4A expression and sex-dimorphism of C4 between males and females was observed. STUDY DESIGN A total of 613 patients with DSM-IV SCZ or schizoaffective disorder (SCZ-AFF) were recruited to investigate the relationship between C4 gene variants and clinical characteristics of SCZ (age of onset, symptom severity, and global assessment of functioning (GAF)). This study also explored the effect of sex on the association of C4 with SCZ. 434 patients were included in the final analyses after genetic quality control. RESULTS We observed associations between C4 and clinical characteristics of SCZ (age of onset, symptom severity, GAF) and found significant differences when males and females were examined separately. CONCLUSION Overall, our preliminary findings encourage future investigations of C4 in SCZ-related phenotypes, including antipsychotic response and side effects. The study sample was of moderate size; therefore, further studies in larger samples are needed to extend and validate these results.
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Affiliation(s)
- Cheng C Chen
- Tanenbaum Centre for Pharmacogenetics, Molecular Brain Science, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Joshua Howie
- Department of Psychiatry, University of Saskatchewan, Saskatoon, Canada
| | - Mahbod Ebrahimi
- Tanenbaum Centre for Pharmacogenetics, Molecular Brain Science, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Kowsar Teymouri
- Tanenbaum Centre for Pharmacogenetics, Molecular Brain Science, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Julia J Woo
- Department of Psychiatry and Behavioural Neurosciences, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Arun K Tiwari
- Tanenbaum Centre for Pharmacogenetics, Molecular Brain Science, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Clement C Zai
- Tanenbaum Centre for Pharmacogenetics, Molecular Brain Science, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - James L Kennedy
- Tanenbaum Centre for Pharmacogenetics, Molecular Brain Science, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
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Li W, Li X, Ma X, Xiao W, Zhang J. Mapping the m1A, m5C, m6A and m7G methylation atlas in zebrafish brain under hypoxic conditions by MeRIP-seq. BMC Genomics 2022; 23:105. [PMID: 35135476 PMCID: PMC8822802 DOI: 10.1186/s12864-022-08350-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 01/31/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The epigenetic modifications play important regulatory roles in tissue development, maintenance of physiological functions and pathological process. RNA methylations, including newly identified m1A, m5C, m6A and m7G, are important epigenetic modifications. However, how these modifications are distributed in the transcriptome of vertebrate brains and whether their abundance is altered under pathological conditions are still poorly understood. In this study, we chose the model animal of zebrafish to conduct a systematic study to investigate the mRNA methylation atlas in the brain. RESULTS By performing unbiased analyses of the m1A, m5C, m6A and m7G methylation of mRNA, we found that within the whole brain transcriptome, with the increase of the gene expression levels, the overall level of each of these four modifications on the related genes was also progressively increased. Further bioinformatics analysis indicated that the zebrafish brain has an abundance of m1A modifications. In the hypoxia-treated zebrafish brains, the proportion of m1A is decreased, affecting the RNA splicing and zebrafish endogenous retroviruses. CONCLUSIONS Our study presents the first comprehensive atlas of m1A, m5C, m6A and m7G in the epitranscriptome of the zebrafish brain and reveals the distribution of these modifications in mRNA under hypoxic conditions. These data provide an invaluable resource for further research on the involvement of m1A, m5C, m6A and m7G in the regulation of miRNA and repeat elements in vertebrates, and provide new thoughts to study the brain hypoxic injury on the aspect of epitranscriptome.
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Affiliation(s)
- Wei Li
- Affiliated Hospital of Guangdong Medical University & Key Laboratory of Zebrafish Model for Development and Disease of Guangdong Medical University, Zhanjiang, 524001, China
| | - Xiaoyu Li
- Affiliated Hospital of Guangdong Medical University & Key Laboratory of Zebrafish Model for Development and Disease of Guangdong Medical University, Zhanjiang, 524001, China
| | - Xunjie Ma
- Affiliated Hospital of Guangdong Medical University & Key Laboratory of Zebrafish Model for Development and Disease of Guangdong Medical University, Zhanjiang, 524001, China
| | - Wei Xiao
- Affiliated Hospital of Guangdong Medical University & Key Laboratory of Zebrafish Model for Development and Disease of Guangdong Medical University, Zhanjiang, 524001, China
| | - Jingjing Zhang
- Affiliated Hospital of Guangdong Medical University & Key Laboratory of Zebrafish Model for Development and Disease of Guangdong Medical University, Zhanjiang, 524001, China.
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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: 19] [Impact Index Per Article: 6.3] [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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Hu L, Uzhameckis D, Hedborg F, Blomberg J. Dynamic and selective HERV RNA expression in neuroblastoma cells subjected to variation in oxygen tension and demethylation. APMIS 2016; 124:140-9. [PMID: 26818268 DOI: 10.1111/apm.12494] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 11/09/2015] [Indexed: 12/15/2022]
Abstract
We studied HERV expression in cell lines after hypoxia, mitogenic stimulation, and demethylation, to better understand if hypoxia may play a role in ERV activation also within the nervous system, as represented by neuroblastoma cell lines. The level of RNA of four human ERV groups (HERVs) (HERVE, I/T, H, and W), and three housekeeping genes, of different cell lines including A549, COS-1, Namalwa, RD-L and Vero-E6, as well as human neuroblastoma cell lines SH-SY5Y, SK-N-DZ, and SK-N-AS were studied using reverse transcription and real-time quantitative PCR (QPCR). During the course of recovery from hypoxia a pronounced and selective activation of RNA expression of HERVW-like sequences, but not of HERVE, I/T, H, and three housekeeping genes, was found in the neuroblastoma cell lines, most pronounced in SK-N-DZ. In the SK-N-DZ cell line, we also tested the expression of HERVs after chemical treatments. HERVW-like sequences were selectively upregulated by 5-azacytidine, a demethylating agent. Some HERVW loci seem especially responsive to hypoxia and demethylation. HERV expression in neuroblastoma cells is selectively and profoundly influenced by some physiological and chemical stimuli.
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Affiliation(s)
- Lijuan Hu
- Section of Virology, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Dmitrijs Uzhameckis
- Section of Virology, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Fredrik Hedborg
- Department of Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Jonas Blomberg
- Section of Virology, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
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Sekar A, Bialas AR, de Rivera H, Davis A, Hammond TR, Kamitaki N, Tooley K, Presumey J, Baum M, Van Doren V, Genovese G, Rose SA, Handsaker RE, Daly MJ, Carroll MC, Stevens B, McCarroll SA. Schizophrenia risk from complex variation of complement component 4. Nature 2016; 530:177-83. [PMID: 26814963 PMCID: PMC4752392 DOI: 10.1038/nature16549] [Citation(s) in RCA: 1554] [Impact Index Per Article: 194.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 12/18/2015] [Indexed: 02/07/2023]
Abstract
Schizophrenia is a heritable brain illness with unknown pathogenic mechanisms. Schizophrenia's strongest genetic association at a population level involves variation in the major histocompatibility complex (MHC) locus, but the genes and molecular mechanisms accounting for this have been challenging to identify. Here we show that this association arises in part from many structurally diverse alleles of the complement component 4 (C4) genes. We found that these alleles generated widely varying levels of C4A and C4B expression in the brain, with each common C4 allele associating with schizophrenia in proportion to its tendency to generate greater expression of C4A. Human C4 protein localized to neuronal synapses, dendrites, axons, and cell bodies. In mice, C4 mediated synapse elimination during postnatal development. These results implicate excessive complement activity in the development of schizophrenia and may help explain the reduced numbers of synapses in the brains of individuals with schizophrenia.
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Affiliation(s)
- Aswin Sekar
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
- MD-PhD Program, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Allison R Bialas
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Heather de Rivera
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Avery Davis
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Timothy R Hammond
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Nolan Kamitaki
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Katherine Tooley
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Jessy Presumey
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Matthew Baum
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
- MD-PhD Program, Harvard Medical School, Boston, Massachusetts 02115, USA
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Vanessa Van Doren
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Giulio Genovese
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Samuel A Rose
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Robert E Handsaker
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Mark J Daly
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
- Analytical and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Michael C Carroll
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Beth Stevens
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Steven A McCarroll
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
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Christensen T. Human endogenous retroviruses in neurologic disease. APMIS 2016; 124:116-26. [DOI: 10.1111/apm.12486] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 10/26/2015] [Indexed: 12/13/2022]
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7
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Buslei R, Strissel PL, Henke C, Schey R, Lang N, Ruebner M, Stolt CC, Fabry B, Buchfelder M, Strick R. Activation and regulation of endogenous retroviral genes in the human pituitary gland and related endocrine tumours. Neuropathol Appl Neurobiol 2015; 41:180-200. [PMID: 24635849 DOI: 10.1111/nan.12136] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 03/10/2014] [Indexed: 12/29/2022]
Abstract
AIMS Adenohypophysis (AH) hormone-producing cells represent the origin of diverse groups of pituitary adenomas (PA). Deregulation of hypothalamic hormone receptors, growth factors and cAMP signalling have been implicated in the aetiology of PA. Endogenous retroviruses (ERVs) are derived from past exogenous retroviral infections and represent more than 8% of the human genome. Some ERV genes encode open reading frames and produce functional proteins, for example, the ERVW-1 envelope gene Syncytin-1, essential for placentogenesis, but also deregulated in human tumours. Data concerning ERV expression in the AH and related endocrine tumours are missing. METHODS Syncytin-1 protein was analysed in normal AH (n = 15) and compared with five PA subtypes (n = 117) by immunohistochemistry. Absolute gene expression of 20 ERV functional envelope genes and ERVW-5 gag was measured. PA tissues were examined for Syncytin-1 and the cAMP signalling marker phospho-CREB-Ser133 using immunohistochemistry. Isolated primary human PA cells were treated with different hormones. Murine embryonic and adult pituitary gland ERV expressions were compared with human AH. RESULTS Syncytin-1 protein colocalized with corticotropic cells of AH. In contrast, all PA demonstrated significant Syncytin-1 protein overexpression, supporting deregulation. All other ERV genes showed significant up-regulations in different PA subtypes. Phospho-CREB-Ser133 and Syncytin-1 colocalized in PA cells. Cultivated primary PA cells with ACTH or CRH induced their respective receptors and ERV genes. Syncytin-A/-B, murine orthologues to human Syncytin-1/-2, localized to embryonic and adult pituitary glands demonstrating functional mammalian conservation. CONCLUSIONS Deregulated ERV genes may contribute to PA development via cAMP signalling.
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Affiliation(s)
- Rolf Buslei
- Institute of Neuropathology, University-Clinic Erlangen, Lab for Molecular Medicine, Erlangen, Germany
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Douville R, Liu J, Rothstein J, Nath A. Identification of active loci of a human endogenous retrovirus in neurons of patients with amyotrophic lateral sclerosis. Ann Neurol 2011; 69:141-51. [PMID: 21280084 DOI: 10.1002/ana.22149] [Citation(s) in RCA: 219] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Amyotrophic lateral sclerosis (ALS) is characterized by the progressive loss of motor neurons, of unknown etiology. Previous studies showed reverse transcriptase in serum of ALS patients at levels comparable to human immunodeficiency virus-infected patients; however, the source and significance of the retroviral elements is uncertain. METHODS Expression of a human endogenous retrovirus (HERV-K) was determined in autopsy brain tissue of patients with ALS and compared to control populations by real-time polymerase chain reaction followed by sequencing of the amplified genes and confirmed by immunostaining. RESULTS HERV-K pol transcripts were increased in patients with ALS compared to those with chronic systemic illness, but could not be detected in Parkinson disease or in the accidental death controls. Sequencing revealed several actively transcribed loci in the HML-2 and 3 subfamilies of HERV-K, with a specific pattern of expression including intact open reading frames and the transcription of a unique locus in ALS. The frequency of intact pol transcripts was highest in the motor cortex, and the reverse transcriptase protein was localized to cortical neurons of ALS patients. HERV-K expression strongly correlated with TDP-43, a multifunctional protein known to be dysregulated in ALS. INTERPRETATION We have identified a specific pattern of HERV-K expression in ALS, which may potentially define the pathophysiology of ALS. Targeting of activated genome-encoded retroviral elements may open new prospects for the treatment of ALS.
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Affiliation(s)
- Renée Douville
- Department of Neurology, Johns Hopkins University, Baltimore, MD, USA
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10
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Abstract
In humans, exogenous retroviruses are known to cause immunodeficiency and neurological disease. While endogenous retroviruses are firmly established pathogens in other species, the human endogenous retroviruses (HERVs) may well be considered as emerging pathogens. HERVs also exhibit complex interactions with exogenous retroviruses and herpesviruses. Two neurological disorders in particular are associated with HERVs: multiple sclerosis (MS) and schizophrenia. HERV-H/F and HERV-W are specifically activated both in the circulation and the central nervous system (CNS) in a majority of MS patients, and particularly, the envelopes (env transcription and Env proteins) appear strongly associated with disease activity. Interferon beta (IFN-beta) therapy is well-established for MS. IFN-beta is also known to have anti-retroviral activities toward exogenous retroviruses (HIV and HTLV-I). New reports show that IFN-beta also mediate down-regulation of HERV-H/F and HERV-W in MS patients. HERV-W and HERV-K transcription (gag and pol) appears, to some extent, to be up-regulated in the circulation and the CNS of patients with schizophrenia. The expression of anti-HERV-W Gag reactive epitopes is reported to be down-regulated in the brain but up-regulated in the blood from schizophrenia patients. The pathogenic potential of HERVs certainly merits further studies.
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The LTR of endogenous retrovirus ev21 retains promoter activity and exhibits tissue specific transcription in chicken. Sci Bull (Beijing) 2010. [DOI: 10.1007/s11434-009-0547-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Mobilization of endogenous retroviruses in mice after infection with an exogenous retrovirus. J Virol 2008; 83:2429-35. [PMID: 19116259 DOI: 10.1128/jvi.01926-08] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Mammalian genomes harbor a large number of retroviral elements acquired as germ line insertions during evolution. Although many of the endogenous retroviruses are defective, several contain one or more intact viral genes that are expressed under certain physiological or pathological conditions. This is true of the endogenous polytropic retroviruses that generate recombinant polytropic murine leukemia viruses (MuLVs). In these recombinants the env gene sequences of exogenous ecotropic MuLVs are replaced with env gene sequences from an endogenous polytropic retrovirus. Although replication-competent endogenous polytropic retroviruses have not been observed, the recombinant polytropic viruses are capable of replicating in numerous species. Recombination occurs during reverse transcription of a virion RNA heterodimer comprised of an RNA transcript from an endogenous polytropic virus and an RNA transcript from an exogenous ecotropic MuLV RNA. It is possible that homodimers corresponding to two full-length endogenous RNA genomes are also packaged. Thus, infection by an exogenous virus may result not only in recombination with endogenous sequences, but also in the mobilization of complete endogenous retrovirus genomes via pseudotyping within exogenous retroviral virions. We report that the infection of mice with an ecotropic virus results in pseudotyping of intact endogenous viruses that have not undergone recombination. The endogenous retroviruses infect and are integrated into target cell genomes and subsequently replicate and spread as pseudotyped viruses. The mobilization of endogenous retroviruses upon infection with an exogenous retrovirus may represent a major interaction of exogenous retroviruses with endogenous retroviruses and may have profound effects on the pathogenicity of retroviral infections.
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Identification of putative endogenous retroviruses actively transcribed in the brain. Virus Genes 2008; 36:439-47. [PMID: 18343986 DOI: 10.1007/s11262-008-0216-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Accepted: 02/21/2008] [Indexed: 10/22/2022]
Abstract
Remnant proviral sequences in the genome resulting from the ancient germline infection of exogenous retroviruses are called endogenous retroviruses (ERVs). The transcriptional activation of human ERVs (HERVs) in the brain of patients with some neurologic diseases suggests that ERVs may participate in certain disease processes in the central nervous system. In this study, we identified putative murine ERVs (MuERVs) which are transcriptionally active in the brain and characterized their biological properties to better understand the ERVs' roles in the brain pathophysiology. The brain and selective non-nervous tissues (heart, muscle, adrenal gland, and salivary gland) of female C57BL/6J mice were subjected to RT-PCR analyses of MuERV expression by amplifying the 3'-end U3 regions and full-length/subgenomic transcripts. The expression patterns of the U3 regions and subgenomic transcripts in the brain were unique compared to the other tissues as well as the genomic MuERV profile. Two putative MuERVs (8,027 and 5,668 bp) were mapped on the mouse genome (chromosome 10, and chromosomes 4 and 8, respectively) using the MuERV U3 sequences, which were evidently expressed in the brain, as probes. Biological properties of these putative MuERVs, such as transcription potential, primer binding site, coding potential, integration age, recombination, and flanking host genes, were characterized. In particular, one of the two putative MuERV isolates had coding potentials for intact group specific antigen (gag), and truncated polymerase (pol) and envelope (env) polypeptides, while the other was defective for all three polypeptides. The findings from this study suggest that a specific group of MuERVs are constitutively expressed in the brain and they may participate in normal and pathogenic events pertaining to the brain through their replication gene products (e.g., gag and env polypeptides) as well as interactions with flanking host genes.
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Abstract
In the last 30 years, the study of virus evolution has undergone a transformation. Originally concerned with disease and its emergence, virus evolution had not been well integrated into the general study of evolution. This chapter reviews the developments that have brought us to this new appreciation for the general significance of virus evolution to all life. We now know that viruses numerically dominate all habitats of life, especially the oceans. Theoretical developments in the 1970s regarding quasispecies, error rates, and error thresholds have yielded many practical insights into virus–host dynamics. The human diseases of HIV-1 and hepatitis C virus cannot be understood without this evolutionary framework. Yet recent developments with poliovirus demonstrate that viral fitness can be the result of a consortia, not one fittest type, a basic Darwinian concept in evolutionary biology. Darwinian principles do apply to viruses, such as with Fisher population genetics, but other features, such as reticulated and quasispecies-based evolution distinguish virus evolution from classical studies. The available phylogenetic tools have greatly aided our analysis of virus evolution, but these methods struggle to characterize the role of virus populations. Missing from many of these considerations has been the major role played by persisting viruses in stable virus evolution and disease emergence. In many cases, extreme stability is seen with persisting RNA viruses. Indeed, examples are known in which it is the persistently infected host that has better survival. We have also recently come to appreciate the vast diversity of phage (DNA viruses) of prokaryotes as a system that evolves by genetic exchanges across vast populations (Chapter 10). This has been proposed to be the “big bang” of biological evolution. In the large DNA viruses of aquatic microbes we see surprisingly large, complex and diverse viruses. With both prokaryotic and eukaryotic DNA viruses, recombination is the main engine of virus evolution, and virus host co-evolution is common, although not uniform. Viral emergence appears to be an unending phenomenon and we can currently witness a selective sweep by retroviruses that infect and become endogenized in koala bears.
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Shimabukuro M, Sasaki T, Imamura A, Tsujita T, Fuke C, Umekage T, Tochigi M, Hiramatsu K, Miyazaki T, Oda T, Sugimoto J, Jinno Y, Okazaki Y. Global hypomethylation of peripheral leukocyte DNA in male patients with schizophrenia: a potential link between epigenetics and schizophrenia. J Psychiatr Res 2007; 41:1042-6. [PMID: 17049557 DOI: 10.1016/j.jpsychires.2006.08.006] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2006] [Revised: 07/24/2006] [Accepted: 08/21/2006] [Indexed: 12/19/2022]
Abstract
Genetic and epigenetic factors can potentially alter susceptibility to psychiatric disorders such as schizophrenia. In order to explore the effect of epigenetics on the pathogenesis of schizophrenia, we examined the global methylation level of leukocyte DNA from 210 patients with schizophrenia (124 males and 86 females) and 237 healthy subjects (108 males and 129 females). Methylated deoxycytidine (mC) content in peripheral leukocyte DNA was measured by high performance liquid chromatography (HPLC). We confirmed in the healthy subjects our previous finding that there are sex-dependent differences in mC content (males>females; beta=0.319, p<0.001), in addition to the effect of age (beta=-0.141, p=0.022). We therefore used multiple regression to analyze the data from all subjects by sex, with age as a co-variant. In males, a tendency was observed toward lower mC content in patients than in controls (beta=-0.115, p=0.075), with a significant effect of age (beta=-0.212, p<0.001). This difference was more prominent in younger individuals. In females, no effect of age or disease status on mC content was observed. These results established that there is significant sex-dependent difference in the mC content of human peripheral leukocyte DNA, and raise the possibility that alterations in DNA methylation state are present in patients with schizophrenia.
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Affiliation(s)
- Morihiro Shimabukuro
- Department of Molecular Biology, Ryukyu University School of Medicine, Okinawa 903-0215, Japan
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Yi JM, Kim HS. Molecular Phylogenetic Analysis of the Human Endogenous Retrovirus E (HERV-E) Family in Human Tissues and Human Cancers. Genes Genet Syst 2007; 82:89-98. [PMID: 17396023 DOI: 10.1266/ggs.82.89] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The human genome is estimated to contain up to 50 copies of full-length and truncated members of HERV-E family. They are thought to be involved in human gene transcription. Here we examine the expression pattern and phylogenetic relationships of the HERV-E in diverse human tissues and cancer cells using RT-PCR amplification and bioinformatic tools. The env gene was expressed in many human tissues (brain, prostate, testis, kidney, placenta, spleen, thymus and uterus) but not in heart, liver, lung and skeletal muscle, importantly, HERV-E expression was detected in all cancer cell lines examined (RT4, PFSK-1, BT-474, HCT-116, TE-1, UO-31, Jurkat, HepG2, A549, MCF7, OVCAR-3, MIA-PaCa-2, PC3, LOX-IMVI, AZ521, 2F7, U-937 and C-33A), suggesting that HERV-E family are expressed corresponding to the transcriptional program of human tissues and human cancer cells. Phylogenetic analysis of HERV-E env family from human tissues, cancer cells and our previous data identify two groups (I and II) through evolutionary divergence. Taken together, HERV-E family expression in human tissues and human cancer cells exhibited close relationships of the env gene sequences across human chromosomes. These active HERV-E elements deserve further investigation as potential pathogenic factors in human diseases such as cancers.
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Affiliation(s)
- Joo-Mi Yi
- Division of Biological Sciences, College of Natural Sciences, Pusan National University, Korea
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Shimabukuro M, Jinno Y, Fuke C, Okazaki Y. Haloperidol treatment induces tissue- and sex-specific changes in DNA methylation: a control study using rats. Behav Brain Funct 2006; 2:37. [PMID: 17132176 PMCID: PMC1684254 DOI: 10.1186/1744-9081-2-37] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Accepted: 11/29/2006] [Indexed: 01/03/2023] Open
Abstract
Background We previously found that there is a subtle difference in the global methylation state of blood leukocyte DNA between male subjects with and without schizophrenia. The aim of the current study was to determine whether this difference was a primary effect of the disease state, or a secondary effect of antipsychotics administered to these patients. Methods We examined the methyl cytosine (mC) content of DNA from the leukocytes, brain, and liver of rats using high performance liquid chromatography. A total of 40 male and female rats received for 21 days daily injection of haloperidol or vehicle solution alone. Results In control rats injected with buffer only, there was a sex-dependent difference in mC content in leukocyte DNA (male > female; P = 0.028, n = 10), similar to our previous observations in human peripheral leukocytes. No difference in mC content between the sexes was observed in the brain or liver in buffer-treated animals. Haloperidol treatment slightly decreased the mC content of leukocytes in male rats, but unexpectedly, increased the mC content of leukocytes in females. We observed a trend toward a higher level of mC in the liver in both sexes following haloperidol treatment, compared to buffer-treated animals. In contrast, haloperidol treatment resulted in a decrease in mC content in the brain in females, and this difference was statistically significant (P = 0.026). Conclusion These results indicate that haloperidol can affect DNA methylation states in the brain, as well as in certain other tissues, and raise the possibility that antipsychotic drugs play a role in the observed disparity in mC content in male subjects with and without schizophrenia.
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Affiliation(s)
- Morihiro Shimabukuro
- Department of Molecular Biology, Ryukyu University School of Medicine, Okinawa, Japan
| | - Yoshihiro Jinno
- Department of Molecular Biology, Ryukyu University School of Medicine, Okinawa, Japan
| | - Chiaki Fuke
- Department of Legal Medicine, School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Yuji Okazaki
- Department of Psychiatry, Mie University School of Medicine, Mie, Japan
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Otowa T, Tochigi M, Rogers M, Umekage T, Kato N, Sasaki T. Insertional polymorphism of endogenous retrovirus HERV-K115 in schizophrenia. Neurosci Lett 2006; 408:226-9. [PMID: 17000049 DOI: 10.1016/j.neulet.2006.09.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Revised: 08/20/2006] [Accepted: 09/03/2006] [Indexed: 11/24/2022]
Abstract
Retroviruses are implicated in the pathogenesis of schizophrenia. Human endogenous retrovirus type K115 (HERV-K115) is a full-length, potentially transcriptional retrovirus and is also polymorphic. We investigated the frequency of HERV-K115 in Japanese schizophrenia patients and healthy controls. No difference was found in the frequency between patients and controls (8.4% versus 9.4%, respectively). However, a marginal difference was observed in age at onset between the HERV-K positive and negative patients (p=0.057). The HERV-K115 insertion appeared to be more frequent in patients with younger onset than those with later onset. These results preliminarily suggest that HERV-K115 may not be associated with schizophrenia in general, but that it could play a partial role in early precipitation of the disease.
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Affiliation(s)
- Takeshi Otowa
- Department of Neuropsychiatry, Graduate School of Medicine, University of Tokyo, Bunkyo, Tokyo 113-8655, Japan
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Cao X, Yeo G, Muotri AR, Kuwabara T, Gage FH. Noncoding RNAs in the mammalian central nervous system. Annu Rev Neurosci 2006; 29:77-103. [PMID: 16776580 DOI: 10.1146/annurev.neuro.29.051605.112839] [Citation(s) in RCA: 332] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The central nervous system (CNS) is arguably one of the most complex systems in the universe. To understand the CNS, scientists have investigated a variety of molecules, including proteins, lipids, and various small molecules. However, one large class of molecules, noncoding RNAs (ncRNAs), has been relatively unexplored. ncRNAs function directly as structural, catalytic, or regulatory molecules rather than serving as templates for protein synthesis. The increasing variety of ncRNAs being identified in the CNS suggests a strong connection between the biogenesis, dynamics of action, and combinatorial regulatory potential of ncRNAs and the complexity of the CNS. In this review, we give an overview of the diversity and abundance of ncRNAs before delving into specific examples that illustrate their importance in the CNS. In particular, we cover recent evidence for the roles of microRNAs, small nucleolar RNAs, retrotransposons, the NRSE small modulatory RNA, and BC1/BC200 in the CNS. Finally, we speculate why ncRNAs are well adapted to improving organism-environment interactions.
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Affiliation(s)
- Xinwei Cao
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA.
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Aronoff R, Petersen CCH. Controlled and localized genetic manipulation in the brain. J Cell Mol Med 2006; 10:333-52. [PMID: 16796803 PMCID: PMC3933125 DOI: 10.1111/j.1582-4934.2006.tb00403.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Accepted: 04/26/2006] [Indexed: 12/28/2022] Open
Abstract
Brain structure and function are determined in part through experience and in part through our inherited genes. A powerful approach for unravelling the balance between activity-dependent neuronal plasticity and genetic programs is to directly manipulate the genome. Such molecular genetic studies have been greatly aided by the remarkable progress of large-scale genome sequencing efforts. Sophisticated mouse genetic manipulations allow targeted point-mutations, deletions and additions to the mouse genome. These can be regulated through inducible promoters expressing in genetically specified neuronal cell types. However, despite significant progress it remains difficult to target specific brain regions through transgenesis alone. Recent work suggests that transduction vectors, like lentiviruses and adeno-associated viruses, may provide suitable additional tools for localized and controlled genetic manipulation. Furthermore, studies with such vectors may aid the development of human genetic therapies for brain diseases.
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Affiliation(s)
- Rachel Aronoff
- Laboratory of Sensory Processing, Brain Mind Institute, Ecole Polytechnique Fédérale de LausanneLausanne, Switzerland
| | - C C H Petersen
- Laboratory of Sensory Processing, Brain Mind Institute, Ecole Polytechnique Fédérale de LausanneLausanne, Switzerland
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Shen HM, Nakamura A, Sugimoto J, Sakumoto N, Oda T, Jinno Y, Okazaki Y. Tissue specificity of methylation and expression of human genes coding for neuropeptides and their receptors, and of a human endogenous retrovirus K family. J Hum Genet 2006; 51:440-450. [PMID: 16544050 DOI: 10.1007/s10038-006-0382-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Accepted: 01/23/2006] [Indexed: 02/03/2023]
Abstract
The purpose of the present study was to understand the tissue specificity of DNA methylation and the relationship between methylation and expression of genes with essential roles in neurodevelopment and brain function. We chose dopamine receptor genes (DRD1 and DRD2), NCAM, and COMT as examples of genes with CpG islands around the promoter region, and serotonin receptor genes (HTR2A and HTR3A), HCRT, and DRD3 as genes without CpG islands. Methylation states were investigated in fetal brain, fetal liver, placenta, and in adult peripheral leukocytes from three individuals by Southern blot and bisulfite-modified DNA sequencing. A repetitive sequence, human endogenous retrovirus (HERV)-K was also examined. All genes examined were almost completely unmethylated in brains. The genes with CpG islands were unmethylated regardless of their expression state. In contrast, genes without CpG islands showed various methylation patterns, which did not necessarily reflect the transcriptional activity of the genes. Most HERV-K loci were methylated, but some loci showed relatively low methylation in the placenta and liver. Interestingly, we found inter-individual differences in methylation levels in HTR2A and HCRT in the placenta and in some loci of HERV-K in the placenta and liver. The sample with the lowest methylation levels in the two unique genes showed higher methylation of HERV-K loci than the other samples. These results provide detailed information about the methylation states of the genes analyzed and evidence for inter-individual variations in methylation in both unique and repetitive sequences.
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Affiliation(s)
- Hong-Mei Shen
- Department of Molecular Biology, Ryukyu University School of Medicine, 207 Nishihara, Okinawa 903-0215, Japan
| | - Akifumi Nakamura
- Department of Molecular Biology, Ryukyu University School of Medicine, 207 Nishihara, Okinawa 903-0215, Japan
- Department of Neuropsychiatry, Ryukyu University School of Medicine, Okinawa, Japan
| | - Jun Sugimoto
- Department of Molecular Biology, Ryukyu University School of Medicine, 207 Nishihara, Okinawa 903-0215, Japan
| | - Noboru Sakumoto
- Department of Neuropsychiatry, Ryukyu University School of Medicine, Okinawa, Japan
| | - Takaya Oda
- Department of Molecular Biology, Ryukyu University School of Medicine, 207 Nishihara, Okinawa 903-0215, Japan
| | - Yoshihiro Jinno
- Department of Molecular Biology, Ryukyu University School of Medicine, 207 Nishihara, Okinawa 903-0215, Japan.
| | - Yuji Okazaki
- Department of Neuropsychiatry, Mie University School of Medicine, Mie, Japan
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Okahara G, Matsubara S, Oda T, Sugimoto J, Jinno Y, Kanaya F. Expression analyses of human endogenous retroviruses (HERVs): tissue-specific and developmental stage-dependent expression of HERVs. Genomics 2004; 84:982-90. [PMID: 15533715 DOI: 10.1016/j.ygeno.2004.09.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2004] [Accepted: 09/07/2004] [Indexed: 10/26/2022]
Abstract
The evolutional and biological roles of human endogenous retroviruses (HERVs) are less recognized compared to those of L1. In the present study, we focused on the transcriptional activity of HERVs in normal human tissues and found five HERV loci that are actively expressed in normal tissues. All but one showed tissue specificity of expression: one was expressed in stomach and small intestine and three were in placenta. We subsequently examined by TaqMan-based RT-PCR assays the temporal expression profiles of the three placenta-specific HERVs along with syncytin and syncytin 2 and observed three patterns. Syncytin and HERV-Fb showed almost constant expression through gestations. Syncytin 2 gradually decreased as pregnancy proceeded. In contrast, expression from the HERV-H/F and HERV-K(HML-6) loci increased remarkably in term placentas. Term placentas in general showed larger interindividual differences in HERV expression levels. Our results suggest that HERVs might have more diverse effects than currently thought.
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Affiliation(s)
- Goichi Okahara
- Department of Molecular Biology, Ryukyu University School of Medicine, 207 Uehara, Okinawa 903-0215, Japan
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