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1.
J Vet Sci ; 20(5): e50, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31565893

RESUMO

Porcine endogenous retroviruses (PERVs) integrate into germline DNA as proviral genome that enables vertical transmission from parents to their offspring. The provirus usually survives as part of the host genome rather than as an infectious agent, but may become pathogenic if it crosses species barriers. Therefore, replication-competent PERV should be controlled through selective breeding or knockout technologies. Two microRNAs (miRNAs), dual LTR1 and LTR2, were selected to inhibit the expression of PERV in primary porcine kidney cells. The inhibition efficiency of the miRNAs was compared based on their inhibition of different PERV regions, specifically long terminal repeats (LTRs), gag, pol, and env. Gene expression was quantified using real-time polymerase chain reaction and the C-type reverse transcriptase (RT) activity was determined. The messenger RNA (mRNA) expression of the PERV LTR and env regions was determined in HeLa cells co-cultured with primary porcine kidney cells. The mRNA expression of the LTR, gag, pol, and env regions of PERV was dramatically inhibited by dual miRNA from 24 to 144 h after transfection, with the highest inhibition observed for the LTR and pol regions at 120 h. Additionally, the RT activity of PERV in the co-culture experiment of porcine and human cells was reduced by 84.4% at the sixth passage. The dual LTR 1+2 miRNA efficiently silences PERV in primary porcine kidney cells.


Assuntos
Retrovirus Endógenos/fisiologia , MicroRNAs/metabolismo , Infecções por Retroviridae/veterinária , Doenças dos Suínos/genética , Animais , Linhagem Celular , Retrovirus Endógenos/genética , Rim , Infecções por Retroviridae/genética , Infecções por Retroviridae/virologia , Suínos , Doenças dos Suínos/virologia , Sequências Repetidas Terminais/fisiologia
2.
Int J Mol Sci ; 20(15)2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31357477

RESUMO

Extracellular vesicles (EVs) are important components of the metastatic niche and are crucial in infiltration, metastasis, and immune tolerance processes during tumorigenesis. We hypothesized that human endogenous retroviruses (HERV) positive EVs derived from tumor cellsmay have a role in modulating the innate immune response. The study was conducted in two different colorectal cancer cell lines, representing different stages of cancer development: Caco-2, derived from a non-metastatic colorectal adenocarcinoma, and SK-CO-1, derived from metastatic colorectal adenocarcinoma (ascites). Both cell lines were treated with decitabine to induce global hypomethylation and to reactivate HERV expression. EVs were quantified by nanoparticle tracking analysis, and HERV-positive EV concentrations were measured by flow cytometry. The effect of EVs isolated from both untreated and decitabine-treated cells on the innate immune response was evaluated by injecting them in zebrafish embryos and then assessing Interleukin 1ß (IL1-ß), Interleukin 10 (IL-10), and the myeloperoxidase (mpx) expression levels by real-time qPCR. Interestingly, HERV-K positive EVs concentrations were significantly associated with a reduced expression of IL1-ß and mpx, supporting our hypothesis that HERV-positive EVs may act as immunomodulators in tumor progression. The obtained results open new perspectives about the modulation of the immune response in cancer therapy.


Assuntos
Neoplasias Colorretais/etiologia , Neoplasias Colorretais/metabolismo , Retrovirus Endógenos/fisiologia , Vesículas Extracelulares/metabolismo , Imunidade Inata , Animais , Linhagem Celular Tumoral , Transformação Celular Neoplásica/imunologia , Transformação Celular Neoplásica/metabolismo , Neoplasias Colorretais/patologia , Metilação de DNA , Modelos Animais de Doenças , Humanos , Peixe-Zebra
3.
BMC Med Genomics ; 12(1): 58, 2019 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-31046767

RESUMO

BACKGROUND: Human Endogenous Retroviruses type K HML-2 (HK2) are integrated into 117 or more areas of human chromosomal arms while two newly discovered HK2 proviruses, K111 and K222, spread extensively in pericentromeric regions, are the first retroviruses discovered in these areas of our genome. METHODS: We use PCR and sequencing analysis to characterize pericentromeric K111 proviruses in DNA from individuals of diverse ethnicities and patients with different diseases. RESULTS: We found that the 5' LTR-gag region of K111 proviruses is missing in certain individuals, creating pericentromeric instability. K111 deletion (-/- K111) is seen in about 15% of Caucasian, Asian, and Middle Eastern populations; it is missing in 2.36% of African individuals, suggesting that the -/- K111 genotype originated out of Africa. As we identified the -/-K111 genotype in Cutaneous T-cell lymphoma (CTCL) cell lines, we studied whether the -/-K111 genotype is associated with CTCL. We found a significant increase in the frequency of detection of the -/-K111 genotype in Caucasian patients with severe CTCL and/or Sézary syndrome (n = 35, 37.14%), compared to healthy controls (n = 160, 15.6%) [p = 0.011]. The -/-K111 genotype was also found to vary in HIV-1 infection. Although Caucasian healthy individuals have a similar frequency of detection of the -/- K111 genotype, Caucasian HIV Long-Term Non-Progressors (LTNPs) and/or elite controllers, have significantly higher detection of the -/-K111 genotype (30.55%; n = 36) than patients who rapidly progress to AIDS (8.5%; n = 47) [p = 0.0097]. CONCLUSION: Our data indicate that pericentromeric instability is associated with more severe CTCL and/or Sézary syndrome in Caucasians, and appears to allow T-cells to survive lysis by HIV infection. These findings also provide new understanding of human evolution, as the -/-K111 genotype appears to have arisen out of Africa and is distributed unevenly throughout the world, possibly affecting the severity of HIV in different geographic areas.


Assuntos
Centrômero/virologia , Retrovirus Endógenos/genética , Retrovirus Endógenos/fisiologia , Variação Genética , Infecções por HIV/virologia , Linfoma Cutâneo de Células T/virologia , Síndrome de Sézary/virologia , Animais , Linhagem Celular , Genótipo , Humanos
4.
PLoS Biol ; 17(5): e3000278, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31095565

RESUMO

Evidence is rapidly mounting that transposable element (TE) expression and replication may impact biology more widely than previously thought. This includes potential effects on normal physiology of somatic tissues and dysfunctional impacts in diseases associated with aging, such as cancer and neurodegeneration. Investigation of the biological impact of mobile elements in somatic cells will be greatly facilitated by the use of donor elements that are engineered to report de novo events in vivo. In multicellular organisms, reporter constructs demonstrating engineered long interspersed nuclear element (LINE-1; L1) mobilization have been in use for quite some time, and strategies similar to L1 retrotransposition reporter assays have been developed to report replication of Ty1 elements in yeast and mouse intracisternal A particle (IAP) long terminal repeat (LTR) retrotransposons in cultivated cells. We describe a novel approach termed cellular labeling of endogenous retrovirus replication (CLEVR), which reports replication of the gypsy element within specific cells in vivo in Drosophila. The gypsy-CLEVR reporter reveals gypsy replication both in cell culture and in individual neurons and glial cells of the aging adult fly. We also demonstrate that the gypsy-CLEVR replication rate is increased when the short interfering RNA (siRNA) silencing system is genetically disrupted. This CLEVR strategy makes use of universally conserved features of retroviruses and should be widely applicable to other LTR retrotransposons, endogenous retroviruses (ERVs), and exogenous retroviruses.


Assuntos
Envelhecimento/genética , Técnicas de Cultura de Células/métodos , Drosophila melanogaster/genética , Retrovirus Endógenos/fisiologia , Neuroglia/metabolismo , Neurônios/metabolismo , Retroelementos/genética , Replicação Viral/fisiologia , Animais , Senescência Celular/genética , Drosophila melanogaster/fisiologia , Retrovirus Endógenos/genética , Genes Reporter , Engenharia Genética , Mutação/genética , Coloração e Rotulagem
5.
EBioMedicine ; 41: 427-442, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30827930

RESUMO

BACKGROUND: Transcriptional dysregulation drives cancer formation but the underlying mechanisms are still poorly understood. Renal cell carcinoma (RCC) is the most common malignant kidney tumor which canonically activates the hypoxia-inducible transcription factor (HIF) pathway. Despite intensive study, novel therapeutic strategies to target RCC have been difficult to develop. Since the RCC epigenome is relatively understudied, we sought to elucidate key mechanisms underpinning the tumor phenotype and its clinical behavior. METHODS: We performed genome-wide chromatin accessibility (DNase-seq) and transcriptome profiling (RNA-seq) on paired tumor/normal samples from 3 patients undergoing nephrectomy for removal of RCC. We incorporated publicly available data on HIF binding (ChIP-seq) in a RCC cell line. We performed integrated analyses of these high-resolution, genome-scale datasets together with larger transcriptomic data available through The Cancer Genome Atlas (TCGA). FINDINGS: Though HIF transcription factors play a cardinal role in RCC oncogenesis, we found that numerous transcription factors with a RCC-selective expression pattern also demonstrated evidence of HIF binding near their gene body. Examination of chromatin accessibility profiles revealed that some of these transcription factors influenced the tumor's regulatory landscape, notably the stem cell transcription factor POU5F1 (OCT4). Elevated POU5F1 transcript levels were correlated with advanced tumor stage and poorer overall survival in RCC patients. Unexpectedly, we discovered a HIF-pathway-responsive promoter embedded within a endogenous retroviral long terminal repeat (LTR) element at the transcriptional start site of the PSOR1C3 long non-coding RNA gene upstream of POU5F1. RNA transcripts are induced from this promoter and read through PSOR1C3 into POU5F1 producing a novel POU5F1 transcript isoform. Rather than being unique to the POU5F1 locus, we found that HIF binds to several other transcriptionally active LTR elements genome-wide correlating with broad gene expression changes in RCC. INTERPRETATION: Integrated transcriptomic and epigenomic analysis of matched tumor and normal tissues from even a small number of primary patient samples revealed remarkably convergent shared regulatory landscapes. Several transcription factors appear to act downstream of HIF including the potent stem cell transcription factor POU5F1. Dysregulated expression of POU5F1 is part of a larger pattern of gene expression changes in RCC that may be induced by HIF-dependent reactivation of dormant promoters embedded within endogenous retroviral LTRs.


Assuntos
Retrovirus Endógenos/genética , Epigenômica , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Sítios de Ligação , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/mortalidade , Carcinoma de Células Renais/patologia , Linhagem Celular Tumoral , Redutases do Citocromo/genética , Retrovirus Endógenos/fisiologia , Regulação Neoplásica da Expressão Gênica , Humanos , Fator 1 Induzível por Hipóxia/genética , Neoplasias Renais/genética , Neoplasias Renais/mortalidade , Neoplasias Renais/patologia , Fator 3 de Transcrição de Octâmero/genética , Fator 3 de Transcrição de Octâmero/metabolismo , Diester Fosfórico Hidrolases/genética , Regiões Promotoras Genéticas , Proteínas/genética , Pirofosfatases/genética , Taxa de Sobrevida , Sequências Repetidas Terminais/genética , Enzimas de Conjugação de Ubiquitina/genética
6.
PLoS One ; 14(2): e0212970, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30818388

RESUMO

Human endogenous retroviruses are remnants of ancient germline infections that make up approximately 8% of the modern human genome. The HERV-K (HML-2) family is one of the most recent entrants into the human germline, these viruses appear to be transcriptionally active, and HERV-K viral like particles (VLPs) are found in cell lines from a number of human malignancies. HERV-K VLPs were first found to be produced in teratocarcinoma cell lines, and since then teratocarcinoma has been thought of as the classical model for HERV-Ks, with the NCCIT teratocarcinoma cell line particularly known to produce VLPs. Treatment for teratocarcinoma has progressed since its discovery, with improved prognosis for patients. Since the introduction of platinum based therapy, first year survival has greatly improved even with disseminated disease; however, it is estimated that 20% to 30% of patients present with metastatic germ cell tumor relapse following initial treatments. Also, the toxicity associated with the use of chemotherapeutic agents used to treat germ cell tumors is still a major concern. In this study, we show that the depletion of the HERV-K accessory protein Np9 increases the sensitivity of NCCIT teratocarcinoma cells to bleomycin and cisplatin. While decreasing the expression of Np9 had only a modest effect on the baseline viability of the cells, the reduced expression of Np9 increased the sensitivity of the teratocarcinoma cells to environmental (serum starvation) and chemical (chemotherapeutic) stresses. Np9 is also essential to the migration of NCCIT teratocarcinoma cells: in a wound closure assay, reduced expression of Np9 resulted in cells migrating into the wound at a slower rate, whereas reintroduction of Np9 resulted in NCCIT cells migrating back into the wound in a manner similar to the control. These findings support the implication that the HERV-K accessory protein Np9 has oncogenic potential.


Assuntos
Retrovirus Endógenos/fisiologia , Produtos do Gene env/fisiologia , Teratocarcinoma/fisiopatologia , Teratocarcinoma/virologia , Antineoplásicos/farmacologia , Bleomicina/farmacologia , Linhagem Celular Tumoral , Movimento Celular , Sobrevivência Celular , Cisplatino/farmacologia , Resistencia a Medicamentos Antineoplásicos , Retrovirus Endógenos/genética , Retrovirus Endógenos/patogenicidade , Produtos do Gene env/genética , Humanos , Masculino , Teratocarcinoma/patologia , Neoplasias Testiculares/patologia , Neoplasias Testiculares/fisiopatologia , Neoplasias Testiculares/virologia
7.
J Gen Virol ; 100(4): 656-661, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30767852

RESUMO

The release of porcine endogenous retrovirus (PERV) particles from pig cells is a potential risk factor during xenotransplantation by way of productively infecting the human transplant recipient. Potential countermeasures against PERV replication are restriction factors that block retroviral replication. SAMHD1 is a triphosphohydrolase that depletes the cellular pool of dNTPs in non-cycling cells starving retroviral reverse transcription. We investigated the antiviral activity of human SAMHD1 against PERV and found that SAMHD1 potently restricts its reverse transcription in human monocytes, monocyte-derived dendritic cells (MDDC), or macrophages (MDM) and in monocytic THP-1 cells. Degradation of SAMHD1 by SIVmac Vpx or CRISPR/Cas9 knock-out of SAMHD1 allowed for PERV reverse transcription. Addition of deoxynucleosides alleviated the SAMHD1-mediated restriction suggesting that SAMHD1-mediated degradation of dNTPs restricts PERV replication in these human immune cells. In conclusion, our findings highlight SAMHD1 as a potential barrier to PERV transmission from pig transplants to human recipients during xenotransplantation.


Assuntos
Retrovirus Endógenos/fisiologia , Xenoenxertos/metabolismo , Xenoenxertos/virologia , Proteína 1 com Domínio SAM e Domínio HD/metabolismo , Animais , Sistemas CRISPR-Cas/fisiologia , Linhagem Celular , Células HEK293 , Humanos , Macrófagos/metabolismo , Macrófagos/virologia , Monócitos/metabolismo , Monócitos/virologia , Transcrição Reversa/fisiologia , Suínos , Células THP-1 , Transplante Heterólogo/métodos , Replicação Viral/fisiologia
8.
G3 (Bethesda) ; 9(3): 855-865, 2019 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-30658967

RESUMO

All genomes contain repeated sequences that are known as transposable elements (TEs). Among these are endogenous retroviruses (ERVs), which are sequences similar to retroviruses and are transmitted across generations from parent to progeny. These sequences are controlled in genomes through epigenetic mechanisms. At the center of the epigenetic control of TEs are small interfering RNAs of the piRNA class, which trigger heterochromatinization of TE sequences. The tirant ERV of Drosophila simulans displays intra-specific variability in copy numbers, insertion sites, and transcription levels, providing us with a well-suited model to study the dynamic relationship between a TE family and the host genome through epigenetic mechanisms. We show that tirant transcript amounts and piRNA amounts are positively correlated in ovaries in normal conditions, unlike what was previously described following divergent crosses. In addition, we describe tirant insertion polymorphism in the genomes of three D. simulans wild-type strains, which reveals a limited number of insertions that may be associated with gene transcript level changes through heterochromatin spreading and have phenotypic impacts. Taken together, our results participate in the understanding of the equilibrium between the host genome and its TEs.


Assuntos
Elementos de DNA Transponíveis , Drosophila simulans/genética , Retrovirus Endógenos/genética , Epigênese Genética , Genoma de Inseto , Interações Hospedeiro-Patógeno , Animais , Drosophila simulans/virologia , Retrovirus Endógenos/fisiologia , Feminino , RNA Interferente Pequeno/metabolismo
9.
Mol Neurobiol ; 56(4): 2590-2605, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30047100

RESUMO

The gammaretroviral human endogenous retrovirus (HERV) families MRSV/HERV-W and HERV-H (including the closely related HERV-Fc1) are associated with an increased risk of multiple sclerosis (MS). Complete HERV sequences betray their endogenous retroviral origin, with open reading frames in gag, pro, pol and env being flanked by two long terminal repeats containing promoter and enhancer sequences with the capacity to regulate HERV transactivation and the activity of host genes in spite of endogenous epigenetic repression mechanisms. HERV virions, RNA, cDNA, Gag and Env, and antibodies to HERV transcriptional products, have variously been found in the blood and/or brain and/or cerebrospinal fluid of MS patients, with the HERV expression level being associated with disease status. Furthermore, some HERV-associated single nucleotide polymorphisms (SNPs), such as rs662139 T/C in a 3-kb region of Xq22.3 containing a HERV-W env locus, and rs391745, upstream of the HERV-Fc1 locus on the X chromosome, are associated with MS susceptibility, while a negative association has been reported with SNPs in the tripartite motif-containing (TRIM) protein-encoding genes TRIM5 and TRIM22. Factors affecting HERV transcription include immune activation and inflammation, since HERV promoter regions possess binding sites for related transcription factors; oxidative stress, with oxidation of guanine to 8-oxoguanine and conversion of cytosine to 5-hydroxymethylcytosine preventing binding of methyl groups transferred by DNA methyltransferases; oxidative stress also inhibits the activity of deacetylases, thereby favouring the acetylation of histone lysine residues favouring gene expression; interferon beta; natalizumab treatment; impaired epigenetic regulation; and the sex of patients.


Assuntos
Retrovirus Endógenos/fisiologia , Esclerose Múltipla/virologia , Progressão da Doença , Retrovirus Endógenos/genética , Epigênese Genética , Humanos , Esclerose Múltipla/patologia , Esclerose Múltipla/fisiopatologia , Polimorfismo Genético , Transcrição Genética
10.
Biol Trace Elem Res ; 191(1): 70-74, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30539386

RESUMO

Human endogenous retroviruses (HERVs) are semi-conserved subtypes of long-terminal repeats containing retrotransposons that constitute approximately 8% of the genome. Under pathological conditions, the expression of HERVs is also affected by epigenetic modifications. The extent to which the activation of human endogenous retroviruses can be influenced upon exposure to copper remains to be evaluated. Thus, the present study was designed to evaluate the effects of CuSO4 administration on the transcriptional activity of three HERV families (H, K, and W) in human malignant melanoma cells. For this purpose, following the determination of less cytotoxic concentrations of copper sulfate, the human skin malignant melanoma SK-MEL-37 cells were treated with 25, 50, and 75 µM CuSO4 for 96 h. Then, mRNA expression of env gene of HERV-H, HERV-K, and HERV-W was evaluated by qPCR. According to the results, 96-h treatment of SK-MEL-37 cells with 75 µM CuSO4 could significantly downregulate HERV-H evn expression (P < 0.05). Moreover, exposure of 25 µM copper significantly upregulated the expression of HERV-K env (P < 0.05). Regarding HERV-W env, the expression level increased significantly in all treated concentrations (P < 0.05). It seems that the expression change was decreased in both HERV-W and HERV-K by increasing doses. The study results demonstrated that copper exposure to melanoma cells might promote tumor growth by inducing HERVs and/or control tumor development by decreasing the activation of HERVs in defined levels of copper. According to the findings of this study, copper might exert a binary effect on malignant melanoma.


Assuntos
Sulfato de Cobre/farmacologia , Retrovirus Endógenos/fisiologia , Melanoma , RNA Mensageiro/biossíntese , RNA Neoplásico/biossíntese , RNA Viral/biossíntese , Neoplasias Cutâneas , Ativação Viral/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Melanoma/metabolismo , Melanoma/patologia , Melanoma/virologia , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/virologia
11.
Proc Natl Acad Sci U S A ; 115(50): 12565-12572, 2018 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-30455304

RESUMO

Endogenous retroviruses (ERVs) are integrated retroviral elements that make up 8% of the human genome. However, the impact of ERVs on human health and disease is not well understood. While select ERVs have been implicated in diseases, including autoimmune disease and cancer, the lack of tools to analyze genome-wide, locus-specific expression of proviral autonomous ERVs has hampered the progress in the field. Here we describe a method called ERVmap, consisting of an annotated database of 3,220 human proviral ERVs and a pipeline that allows for locus-specific genome-wide identification of proviral ERVs that are transcribed based on RNA-sequencing data, and provide examples of the utility of this tool. Using ERVmap, we revealed cell-type-specific ERV expression patterns in commonly used cell lines as well as in primary cells. We identified 124 unique ERV loci that are significantly elevated in the peripheral blood mononuclear cells of patients with systemic lupus erythematosus that represent an IFN-independent signature. Finally, we identified additional tumor-associated ERVs that correlate with cytolytic activity represented by granzyme and perforin expression in breast cancer tissue samples. The open-source code of ERVmap and the accompanied web tool are made publicly available to quantify proviral ERVs in RNA-sequencing data with ease. Use of ERVmap across a range of diseases and experimental conditions has the potential to uncover novel disease-associated antigens and effectors involved in human health that is currently missed by focusing on protein-coding sequences.


Assuntos
Retrovirus Endógenos/genética , Neoplasias da Mama/genética , Neoplasias da Mama/imunologia , Neoplasias da Mama/virologia , Linhagem Celular , Mapeamento Cromossômico , Biologia Computacional , Bases de Dados de Ácidos Nucleicos , Retrovirus Endógenos/imunologia , Retrovirus Endógenos/fisiologia , Feminino , Genoma Humano , Genoma Viral , Humanos , Vigilância Imunológica/genética , Leucócitos Mononucleares/virologia , Lúpus Eritematoso Sistêmico/genética , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/virologia , Provírus/genética , Análise de Sequência de RNA , Transcrição Genética
12.
Crit Rev Microbiol ; 44(6): 715-738, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30318978

RESUMO

The human genome contains a large number of retroviral elements acquired over the process of evolution, some of which are specific to primates. However, as many of these are defective or silenced through epigenetic changes, they were historically considered "junk DNA" and their potential role in human physiology or pathological circumstances have been poorly studied. The most recently acquired, human endogenous retrovirus-K (HERV-K), has multiple copies in the human genome and some of them have complete open reading frames that are transcribed and translated, especially in early embryogenesis. Phylogenetically, HERV-K is considered a supergroup of viruses. One of the subtypes, termed HML-2, seems to be the most active and hence, it is the best studied. Aberrant expression of HML-2 in adult tissues has been associated with certain types of cancer and with neurodegenerative diseases. This review discusses the discovery of these viruses, their classification, structure, regulation and potential for replication, physiological roles, and their involvement in disease pathogenesis. Finally, it presents different therapeutic approaches being considered to target these viruses.


Assuntos
Retrovirus Endógenos/isolamento & purificação , Infecções por Retroviridae/virologia , Retroviridae/isolamento & purificação , Animais , Retrovirus Endógenos/classificação , Retrovirus Endógenos/genética , Retrovirus Endógenos/fisiologia , Genoma Humano , Humanos , Retroviridae/classificação , Retroviridae/genética , Retroviridae/fisiologia , Replicação Viral
13.
PLoS Pathog ; 14(8): e1007123, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30080900

RESUMO

Endogenous retroviruses (ERVs), remnants of ancient germline infections, comprise 8% of the human genome. The most recently integrated includes human ERV-K (HERV-K) where several envelope (env) sequences remain intact. Viral pseudotypes decorated with one of those Envs are infectious. Using a recombinant vesicular stomatitis virus encoding HERV-K Env as its sole attachment and fusion protein (VSV-HERVK) we conducted a genome-wide haploid genetic screen to interrogate the host requirements for infection. This screen identified 11 genes involved in heparan sulfate biosynthesis. Genetic inhibition or chemical removal of heparan sulfate and addition of excess soluble heparan sulfate inhibit infection. Direct binding of heparin to soluble HERV-K Env and purified VSV-HERVK defines it as critical for viral attachment. Cell surface bound VSV-HERVK particles are triggered to infect on exposure to acidic pH, whereas acid pH pretreatment of virions blocks infection. Testing of additional endogenous HERV-K env sequences reveals they bind heparin and mediate acid pH triggered fusion. This work reconstructs and defines key steps in the infectious entry pathway of an extinct virus.


Assuntos
Retrovirus Endógenos/fisiologia , Heparitina Sulfato/metabolismo , Proteínas do Envelope Viral/metabolismo , Tropismo Viral/fisiologia , Internalização do Vírus , Humanos
14.
Immunol Res ; 66(3): 336-339, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29882036

RESUMO

Recent genetic evidence points towards endogenous retroviruses as playing a pivotal role in the causation of multiple sclerosis and possibly other autoimmune diseases. We discuss various ways in which this association could be brought about. Specifically, we suggest that two endogenous retroviruses, HERV-Fc1 and HERV-K13, on chromosomes X and 19, respectively, contribute to the development of autoimmune T cells by transforming them in multiple sclerosis. Partially overlapping sets of endogenous retroviruses may play a role in other autoimmune diseases. If this theory holds true, many scientists may have looked for viruses in the wrong tissue. Ir would also explain why lymphocyte-suppressive agents suppress multiple sclerosis.


Assuntos
Retrovirus Endógenos/fisiologia , Esclerose Múltipla/imunologia , Linfócitos T/fisiologia , Animais , Autoimunidade , Cromossomos Humanos Par 19 , Cromossomos Humanos X/genética , Predisposição Genética para Doença , Humanos , Modelos Imunológicos , Esclerose Múltipla/genética , Esclerose Múltipla/virologia
15.
Front Immunol ; 9: 603, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29706951

RESUMO

The greatest obstacle to a cure for HIV is the provirus that integrates into the genome of the infected cell and persists despite antiretroviral therapy. A "shock and kill" approach has been proposed as a strategy for an HIV cure whereby drugs and compounds referred to as latency-reversing agents (LRAs) are used to "shock" the silent provirus into active replication to permit "killing" by virus-induced pathology or immune recognition. The LRA most utilized to date in clinical trials has been the histone deacetylase (HDAC) inhibitor-vorinostat. Potentially, pathological off-target effects of vorinostat may result from the activation of human endogenous retroviruses (HERVs), which share common ancestry with exogenous retroviruses including HIV. To explore the effects of HDAC inhibition on HERV transcription, an unbiased pharmacogenomics approach (total RNA-Seq) was used to evaluate HERV expression following the exposure of primary CD4+ T cells to a high dose of vorinostat. Over 2,000 individual HERV elements were found to be significantly modulated by vorinostat, whereby elements belonging to the ERVL family (e.g., LTR16C and LTR33) were predominantly downregulated, in contrast to LTR12 elements of the HERV-9 family, which exhibited the greatest signal, with the upregulation of 140 distinct elements. The modulation of three different LTR12 elements by vorinostat was confirmed by droplet digital PCR along a dose-response curve. The monitoring of LTR12 expression during clinical trials with vorinostat may be indicated to assess the impact of this HERV on the human genome and host immunity.


Assuntos
Antirreumáticos/uso terapêutico , Linfócitos T CD4-Positivos/efeitos dos fármacos , Retrovirus Endógenos/fisiologia , Infecções por HIV/tratamento farmacológico , HIV-1/fisiologia , Inibidores de Histona Desacetilases/farmacologia , Vorinostat/farmacologia , Linfócitos T CD4-Positivos/imunologia , Células Cultivadas , Regulação da Expressão Gênica/efeitos dos fármacos , Inibidores de Histona Desacetilases/uso terapêutico , Humanos , Imunidade/efeitos dos fármacos , Provírus/genética , Sequências Repetidas Terminais/genética , Ativação Viral/efeitos dos fármacos , Latência Viral/efeitos dos fármacos , Vorinostat/uso terapêutico
16.
Retrovirology ; 15(1): 34, 2018 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-29716624

RESUMO

BACKGROUND: About 10% of the mouse genome is composed of endogenous retroviruses (ERVs) that represent a molecular fossil record of past retroviral infections. One such retrovirus, murine ERV-L (MuERV-L) is an env-deficient ERV that has undergone episodic proliferation, with the most recent amplification occurring ~ 2 million years ago. MuERV-L related sequences have been co-opted by mice for antiretroviral defense, and possibly as promoters for some genes that regulate totipotency in early mouse embryos. However, MuERV-L sequences present in modern mouse genomes have not been observed to replicate. RESULTS: Here, we describe the reconstruction of an ancestral MuERV-L (ancML) sequence through paleovirological analyses of MuERV-L elements in the modern mouse genome. The resulting MuERV-L (ancML) sequence was synthesized and a reporter gene embedded. The reconstructed MuERV-L (ancML) could replicate in a manner that is dependent on reverse transcription and generated de novo integrants. Notably, MuERV-L (ancML) exhibited a narrow host range. Interferon-α could reduce MuERV-L (ancML) replication, suggesting the existence of interferon-inducible genes that could inhibit MuERV-L replication. While mouse APOBEC3 was able to restrict the replication of MuERV-L (ancML), inspection of endogenous MuERV-L sequences suggested that the impact of APOBEC3 mediated hypermutation on MuERV-L has been minimal. CONCLUSION: The reconstruction of an ancestral MuERV-L sequence highlights the potential for the retroviral fossil record to illuminate ancient events and enable studies of the impact of retroviral elements on animal evolution.


Assuntos
Retrovirus Endógenos/fisiologia , Infecções por Retroviridae/virologia , Replicação Viral , Sequência de Aminoácidos , Animais , Sequência de Bases , Células CHO , Linhagem Celular , Biologia Computacional/métodos , Cricetulus , Citidina Desaminase , Resistência à Doença/genética , Resistência à Doença/imunologia , Retrovirus Endógenos/classificação , Evolução Molecular , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Imunidade Inata , Camundongos , Filogenia , DNA Polimerase Dirigida por RNA/genética , DNA Polimerase Dirigida por RNA/metabolismo , Infecções por Retroviridae/imunologia , Infecções por Retroviridae/metabolismo , Integração Viral
17.
Arch Virol ; 163(7): 1907-1914, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29610985

RESUMO

Although human apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G, hA3G)-mediated deamination is the major mechanism used to restrict the infectivity of a broad range of retroviruses, it is unclear whether porcine endogenous retrovirus (PERV) is affected by hA3G or porcine A3F (poA3F). To determine whether DNA deamination is required for hA3G- and poA3F-dependent inhibition of PERV transmission, we developed VSV-pseudotype PERV-B expressing hA3G, mutant hA3G-E67Q (encapsidation and RNA binding activity-deficient), mutant hA3G-E259Q (deaminase-deficient), or poA3F. hA3G-E67Q decreased virus infectivity by ~ 93% compared to the ~ 99% decrease of viral infectivity by wild-type hA3G, while hA3G-E259Q decreased the infectivity of PERV-B by ~ 35%. These data suggest that cytidine deamination activity is crucial for efficient restriction of PERV by hA3G, but cytidine deamination cannot fully explain the inactivation of PERV by hA3G. Furthermore, differential DNA denaturation PCR (3D-PCR) products from 293T cells infected with PERV-B expressing hA3G mutants were sequenced. G-to-A hypermutation was detected at a frequency of 4.1% for hA3G, 3.4% for hA3G-E67Q, and 4.7% for poA3F. These results also suggest that hA3G and poA3F inhibit PERV by a deamination-dependent mechanism. To examine the effect of hA3G on the production of PERV DNA, genomic DNA was extracted from 293T cells 12 h after infection with PERV expressing hA3G, and this DNA was used as template for real-time PCR. A 50% decrease in minus strand strong stop (-sss) DNA synthesis/transfer was observed in the presence of hA3G. Based on these results, we conclude that hA3G may restrict PERV by both deamination-dependent mechanisms and inhibition of DNA strand transfer during PERV reverse transcription.


Assuntos
Desaminase APOBEC-3G/metabolismo , Citidina Desaminase/metabolismo , Retrovirus Endógenos/genética , Retrovirus Endógenos/fisiologia , Transcrição Reversa , Replicação Viral , Desaminase APOBEC-3G/genética , Animais , Citidina/metabolismo , Citidina Desaminase/deficiência , Citidina Desaminase/genética , Replicação do DNA , DNA Viral/biossíntese , DNA Viral/genética , Desaminação , Células HEK293 , Interações Hospedeiro-Patógeno , Humanos , Mutação , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Suínos/virologia
18.
Nat Commun ; 9(1): 1683, 2018 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-29703894

RESUMO

Subsets of endogenous retroviruses (ERVs) are derepressed in mouse embryonic stem cells (mESCs) deficient for Setdb1, which catalyzes histone H3 lysine 9 trimethylation (H3K9me3). Most of those ERVs, including IAPs, remain silent if Setdb1 is deleted in differentiated embryonic cells; however they are derepressed when deficient for Dnmt1, suggesting that Setdb1 is dispensable for ERV silencing in somatic cells. However, H3K9me3 enrichment on ERVs is maintained in differentiated cells and is mostly diminished in mouse embryonic fibroblasts (MEFs) lacking Setdb1. Here we find that distinctive sets of ERVs are reactivated in different types of Setdb1-deficient somatic cells, including the VL30-class of ERVs in MEFs, whose derepression is dependent on cell-type-specific transcription factors (TFs). These data suggest a more general role for Setdb1 in ERV silencing, which provides an additional layer of epigenetic silencing through the H3K9me3 modification.


Assuntos
Metilação de DNA/fisiologia , Retrovirus Endógenos/fisiologia , Repressão Epigenética/fisiologia , Histona-Lisina N-Metiltransferase/metabolismo , Ativação Viral/genética , Animais , Diferenciação Celular/fisiologia , DNA (Citosina-5-)-Metiltransferase 1/genética , DNA (Citosina-5-)-Metiltransferase 1/metabolismo , Fibroblastos , Genes de Partícula A Intracisternal/genética , Histona-Lisina N-Metiltransferase/genética , Histonas/genética , Interações Hospedeiro-Patógeno/genética , Camundongos , Camundongos Knockout , Células-Tronco Embrionárias Murinas
19.
Retrovirology ; 15(1): 28, 2018 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-29609635

RESUMO

Porcine endogenous retroviruses (PERVs) are present in the genome of all pigs, they infect certain human cells and therefore pose a special risk for xenotransplantation using pig cells, tissues and organs. Xenotransplantation is being developed in order to alleviate the reduced availability of human organs. Despite the fact that PERVs are able to infect certain human cells and cells from other species, transmission of PERVs has not been observed when animals (including non-human primates) were inoculated with PERV preparations or during preclinical xenotransplantations. The data indicate that PERVs were not transmitted because they were not released from the transplant or were inhibited by intracellular restriction factors and innate immunity in the recipient. In a single study in guinea pigs, a transient PERV infection and anti-PERV antibodies were described, indicating that in this case at least, the immune system may also have been involved.


Assuntos
Retrovirus Endógenos/fisiologia , Infecções por Retroviridae/transmissão , Infecções por Retroviridae/virologia , Animais , Células Cultivadas , Interações Hospedeiro-Patógeno , Humanos , Modelos Animais , Primatas , Infecções por Retroviridae/genética , Infecções por Retroviridae/metabolismo , Suínos , Transplante Heterólogo
20.
Clin Immunol ; 191: 37-43, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29567431

RESUMO

Retroviruses including Human Endogenous Retroviruses (HERVs), contain a conserved region with highly immunomodulatory functions in the transmembrane proteins in envelope gene (env) named immunosuppressive domain (ISU). In this report, we demonstrate that Env59-GP3 peptide holds therapeutic potential in a mouse model of myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE). The results show that this specific HERV-H derived ISU peptide, but not peptide derived from another env gene HERV-K, decreased the development of EAE in C57BL/6 mice, accompanied by reduced demyelination and inhibition of inflammatory cells. Moreover, here we tested the effect of peptides on macrophages differentiation. The treatment with Env59-GPS peptide modulate the pro-inflammatory M1 profile and anti-inflammatory M2 macrophages, being shown by inhibiting inflammatory M1 hallmark genes/cytokines expression and enhancing expression of M2 associated markers. These results demonstrate that Env59-GP3 ISU peptide has therapeutic potential in EAE possibly through inducing the polarization of M2 macrophages and inhibiting inflammatory responses.


Assuntos
Encefalomielite Autoimune Experimental/tratamento farmacológico , Retrovirus Endógenos/fisiologia , Imunossupressores/uso terapêutico , Esclerose Múltipla/tratamento farmacológico , Animais , Polaridade Celular , Modelos Animais de Doenças , Encefalomielite Autoimune Experimental/imunologia , Feminino , Humanos , Macrófagos/efeitos dos fármacos , Macrófagos/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Esclerose Múltipla/etiologia , Esclerose Múltipla/imunologia , Peptídeos/uso terapêutico , Medula Espinal/patologia , Proteínas do Envelope Viral/uso terapêutico
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