A Comprehensive Hybridization Model Allows Whole HERV Transcriptome Profiling Using High Density Microarray
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE87134 | GEO | 2016/09/21
SECONDARY ACCESSION(S): PRJNA343656
REPOSITORIES: GEO
Similar Datasets
Project description:Human endogenous retroviruses (HERVs/MaLRs) are distributed among our 24 chromosomes and their long terminal repeats (LTRs) constitute putative regulatory sequences. HERVs have received much attention for their implication in cancer, autoimmunity and placental development. Herein, we used a recently described high-density microarray allowing the exploration of the whole HERVs/MaLRs transcriptome including 353,994 HERVs/MaLRs loci and also 1559 genes related to immunity. We obtained a first view of the HERV transcriptome in peripheral blood mononuclear cells (PBMCs) by using a composite panel of unstimulated, low dose and high dose LPS-stimulated PBMCs from healthy volunteers to mimic inflammatory response or monocyte anergy. About 5.6% of the HERVs/MaLRs repertoire is transcribed in PBMCs. Roughly, one tenth [5.7%-13.1%] of LTRs present a constitutive promoter or polyA function and a quarter [19.5%-27.6%] of LTRs may shift from silent to active LTRs, LTRs being broadly subjected to operational determinism. We provide evidence that some HERVs/MaLRs and genes share similar control of regulation upon LPS stimulation conditions, e.g. presenting a low dose LPS-dependent “tolerizable” profile which can be reversed by INF-g stimulation. Similarly to tissue tropism observed in solid tumors, stimulus-dependent response confirm that the expression of HERVs is tightly regulated in PBMCs. Altogether, these observations allow to integrate 62 HERVs/MaLRs and 26 genes in 11 canonical pathways. We highlight HERVs close to OAS2/3 and IFI44/IFI44L genes. HERV incorporation at the crossroads of immune response pathways, paves the way for further functional studies and analyses of HERV transcriptome in altered immune responses in vivo such as in sepsis.
2018-06-25 | GSE108239 | GEO
Project description:Background: Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. To date, no biomarker has shown sufficient evidence and ease of application in clinical routine to monitor the complexity of the sepsis-related immune alterations. Multiple levels of interaction of human endogenous retroviruses (HERVs) with the immune response led us to hypothesize that they may be relevant candidates both to contribute to the physiopathology of sepsis and to be part of a molecular signature. In this study, we used a recently described high-density microarray which allows exploring HERVs/MaLRs transcriptome in septic shock patients. Results: About 6.9% of the HERVs/MalRs repertoire is transcribed in whole blood. Concerning the functionality of LTRs, the majority of LTRs are silent (62.9%), 7.5% of LTRs present a putative constitutive promoter or polyA functions, while 20.4% of them may shift from silent to active. Evidence was given that a subset of HERVs/MaLRs and genes were modulated in septic shock patients according to the monocyte HLA-DR (mHLA-DR) expression level measured by flow cytometry, as a proxy of immunosuppression. We then identified a large signature consisting of 193 differentially expressed HERVs/MaLRs probesets further reduced to a smaller 10 HERVs/MaLRs signature. Both signatures, validated in an independent septic shock cohort, identified two groups of patients with different severity features including clinical criteria and the CD74 and CX3CR1 sepsis severity molecular markers. Conclusion: This microarray-based approach unveiled the expression of about 87,912 distinct HERV probesets and identified 764 putative promoter LTRs and 642 putative polyA LTRs in whole blood. HERV/MaLR expression was shown to be tightly modulated in septic shock patients according to mHLA-DR expression. We identified a set of potential molecular biomarkers in septic shock patients partially overlapping immunosuppression (mHLA-DR), and the risk of Health Care associated Infections (HAI) (CD74 ratio), complementary to existing molecular markers of a sepsis patients stratification. We identified a HERV/MaLR signature discriminating patients based on their immunosuppression state and severity.
2020-03-30 | GSE121350 | GEO
Project description:Background: Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. To date, no biomarker has shown sufficient evidence and ease of application in clinical routine to monitor the complexity of the sepsis-related immune alterations. Multiple levels of interaction of human endogenous retroviruses (HERVs) with the immune response led us to hypothesize that they may be relevant candidates both to contribute to the physiopathology of sepsis and to be part of a molecular signature. In this study, we used a recently described high-density microarray which allows exploring HERVs/MaLRs transcriptome in septic shock patients. Results: About 6.9% of the HERVs/MalRs repertoire is transcribed in whole blood. Concerning the functionality of LTRs, the majority of LTRs are silent (62.9%), 7.5% of LTRs present a putative constitutive promoter or polyA functions, while 20.4% of them may shift from silent to active. Evidence was given that a subset of HERVs/MaLRs and genes were modulated in septic shock patients according to the monocyte HLA-DR (mHLA-DR) expression level measured by flow cytometry, as a proxy of immunosuppression. We then identified a large signature consisting of 193 differentially expressed HERVs/MaLRs probesets further reduced to a smaller 10 HERVs/MaLRs signature. Both signatures, validated in an independent septic shock cohort, identified two groups of patients with different severity features including clinical criteria and the CD74 and CX3CR1 sepsis severity molecular markers. Conclusion: This microarray-based approach unveiled the expression of about 87,912 distinct HERV probesets and identified 764 putative promoter LTRs and 642 putative polyA LTRs in whole blood. HERV/MaLR expression was shown to be tightly modulated in septic shock patients according to mHLA-DR expression. We identified a set of potential molecular biomarkers in septic shock patients partially overlapping immunosuppression (mHLA-DR), and the risk of Health Care associated Infections (HAI) (CD74 ratio), complementary to existing molecular markers of a sepsis patients stratification. We identified a HERV/MaLR signature discriminating patients based on their immunosuppression state and severity.
2020-03-30 | GSE121349 | GEO
Project description:Human Endogenous Retroviruses (HERVs) are exogenous viral elements that integrated into the germline millions of years ago. They comprise 8% of the human genome and play a critical role in cellular differentiation during development. HERV-K(HML-2) is the most recently integrated and actively transcribed HERV. It is found to be highly expressed in pluripotent stem cells and strongly downregulated during cellular differentiation. Moreover, expression of HERV-K in terminally differentiated neurons results in cytotoxicity. Expression of HERVs has been implicated in carcinogenesis and is suggested to confer stem cell like features important for cell growth. Atypical Teratoid / Rhabdoid Tumor (AT/RT) is a rare pediatric brain cancer that results from incomplete neuronal differentiation during embryonic development. In this paper, we investigated the cytopathic effect of Ouabain, a cardiac glycoside that induces cytotoxicity in stem cells, on AT/RT cells. We characterized four AT/RT cell lines by immunostaining and observed variable levels of stem cell, Oct4 and Pax6, and neuronal differentiation markers, TUBB3 and MAP2, as well as HERV-K envelope (env), polymerase (pol), and gag transcripts. We stained formalin-fixed brain tissues from 20 AT/RT patients and 5 unaffected controls for HERV-K ENV protein expression. 40% of AT/RT patient tissues showed ENV expression. In contrast, no ENV immunostaining was observed in all 5 control brain tissues. We used Ouabain, known to be cytotoxic to stem cells, observed up to 50% toxicity at 24 hr and 80% toxicity at 48 hr after treatment. While AT/RT primarily exist as large cell aggregates in suspension, Ouabain treatment downregulated HERV-K ENV protein and caused disruption of cell-to-cell interactions. Similarly, when AT/RT cells were transfected with a CRISPR/Cas9 construct designed to repress HERV-K promotor activity, cell aggregates separated and cell viability decreased significantly. Using a luciferase reporter construct under the control of a HERV-K promotor, we observed a significant decrease in HERV-K promotor activity at 8 to 72 hr post treatment with 0.5 uM Ouabain. Given that downregulation of HERV-K alone was sufficient to cause cytotoxicity in the cells, HERV-K expression may be essential for AT/RT growth and survival. Ouabain and other compounds that modulate HERV expression may provide an alternative or adjunctive therapeutic option for treatment of embryonal tumors.
2021-06-28 | GSE124210 | GEO
Project description:The HERV-K(HML2) family is a group of elements of retroviral origin that are present in the human genome. They are silenced in most normal tissues, but are induced in a number of human cancers. In order to assess the relevance of their expression in these pathologies, the consequences of ectopic expression of the HERV-K(HML2) envelope protein were analysed in human 293T cells. The cells were transfected with a control vector, or an expression vector for the HERV-K(HML2) envelope protein. Total RNA was extracted 24h and 48h post transfection, and duplicate samples were analysed on whole genome transcriptional microarrays.
2017-06-17 | E-MTAB-5509 | biostudies-arrayexpress
Project description:To check the acetylation levels at the positions harbouring HERV-loci and assess their variation after the treatment with HDACis (Vorinostat, romidepsin), the univocal genomic coordinates of about 3280 HERV-loci have been compared with the position of the H3AcK9 peaks identified by ChIP-seq analysis. The first analysis confirmed that HDACis are able to modulate the acetylation of repetitive elements, including HERV sequences. Subsequently, we considered only the differential peaks (diffpeaks), i.e. the peaks showing significant variation after the treatment with vorinostat and/or romidepsin. Interestingly, even if more than half of HERV-loci co-localised with acetylation peaks after HDACi treatment, only a minority of them (0.9 to 1.9%) co-localised with diffpeaks, showing mostly a reduction in their acetylation levels. Diffpeaks co-localised HERV-loci could be classified into 24 HERV groups and included the ERV-V2 locus. We focused then on the 11 HERV-loci which co-localised with diffpeaks showing an increase in acetylation levels, hence indicating an increased transcriptional activation after HDACi treatment. Remarkably, diffpeaks corresponding to the ERV-V2 locus were identified in all samples and were the most significantly upregulated in both vorinostat and romidepsin treatment. This was in part confirmed by ChIP-qPCR in different OC cells. Beside ERV-V2, only the HML8 sequence at locus 2q11,2 showed increased acetylation levels in all treated samples, independent from the HDACis used, but having lower statistical significance. The analysis revealed that the treatment with HDACis did not only account for the significant increase of ERV-V2 acetylation, but also led to the shift and concentration of acetylation peaks at the 5’ region of the HERV provirus. This observation allows us to hypothesize that HDACi treatment could not only increase ERV-V2 transcriptional activation, but also modify its pattern of expression, and eventually leading to alternative splicing.
2021-01-15 | GSE164809 | GEO
Project description:Human endogenous retroviruses (HERVs) are a sort of transposable elements. HERVs harbor abundant regulatory elements in their sequences and have a potential to work as enhancers modulating the expressions of the adjacent genes. Some HERV-enhancers are particularly activated in cancer cells and suspected to be associated with cancer progression. To verify the enhancer activity of HERVs on the gene expressions in lung adenocarcinoma cells, we established the HERV-excised A549 cell lines using a CRISPR-Cas9 system and performed RNA sequencing (RNA-Seq) analysis of these cells.
2020-09-29 | GSE141141 | GEO
Project description:Background: The human genome consists of considerable portions derived from retroviruses inherited for millions of years. So-called human endogenous retroviruses (HERVs) are usually severely mutated, yet some coding-competent HERVs exist. The HERV-K(HML-2) group includes evolutionarily young proviruses that still encode typical retroviral proteins. HERV-K(HML-2) has been implicated in various human diseases because transcription is often upregulated and some of the encoded proteins are known to affect cell biology. HERV-K(HML-2) Protease (Pro) has received little attention so far, although it appears expressed in some disease contexts and other retroviral proteases are known to process cellular proteins. Results: We set out to identify human cellular proteins being substrates of HERV-K(HML-2) Pro employing a modified Terminal Amine Isotopic Labeling of Substrates (TAILS) procedure. Thousands of human proteins were identified as significantly processed by HERV-K(HML-2) Pro. Identified proteins locate to various cellular compartments and participate in diverse, often disease-relevant cellular processes. We verified cleavage of a majority of selected human proteins in vitro and in vivo. Conclusions: Hundreds, if not thousands of cellular proteins are potential substrates of HERV-K(HML-2) Pro. It is conceivable that even low-level expression of HERV-K(HML-2) Pro has a functional impact on cell biology and thus relevance for human diseases. Specific studies will be required to elucidate effects of HERV-K(HML-2) Pro expression regarding human substrate proteins, cell biology and disease. Endogenous retrovirus-encoded Pro activity may also be relevant for disease development in species other than human.
2019-09-02 | PXD013296 | Pride
Project description:The endogenous retrovirus type W (HERV-W) is a human specific entity, which was initially discovered in multiple sclerosis (MS) patient derived cells. We initially found that the HERV-W envelope (ENV) protein negatively affects oligodendrogenesis and controls microglial cell polarization towards a myelinated axon associated and damaging phenotype. Such first functional assessments were conducted ex vivo, given the human specific origin of HERV-W. Recent experimental evidence gathered on a novel transgenic mouse model, mimicking activation and expression of the HERV-W ENV protein, revealed that all glial cell types are impacted and that cellular fates, differentiation, and functions were changed. In order to identify a HERV-W specific signature in glial cells, the current study analyzed the transcriptome of ENV stimulated microglial- and astroglial cells and compared the transcriptomic signature to lipopolysaccharide (LPS) stimulated cells, owing to the fact that both ligands can activate toll-like receptor-4 (TLR-4). Additionally, a comparison between published disease associated glial signatures and the transcriptome of HERV-W ENV stimulated glial cells was conducted. We, therefore, provide here for the first time a detailed molecular description of specific HERV-W ENV evoked effects on those glial cell populations that are involved in smoldering neuroinflammatory processes relevant for progression of neurodegenerative diseases.
2024-03-30 | GSE262029 | GEO