Custom microchip analysis identifies differentially expressed non-coding RNAs in Epstein-Barr virus-infected B cells
ABSTRACT: Upon Epstein-Barr virus (EBV) infection of human B lymphocytes non-coding RNAs (ncRNAs) regulate expression of viral and cellular genes. In this study, we generated a specialized cDNA library from EBV-immortalized cells and subjected it to deep sequencing. We identified 631 unique ncRNA genes, comprised of 321 potential novel differentially expressed ncRNA candidates. Subsequently, we investigated differential expression of known and potential novel ncRNA candidates by custom-designed microchips by comparing expression of ncRNA genes of EBV-immortalized versus non-infected control cells. Among the differentially expressed candidates from chip analysis, differential expression of six novel ncRNA candidates was verified by northern blot analysis. In addition, microchip analysis resulted in observation of increased expression levels of a significant number of potential ncRNA candidates that were preferentially derived from genomic loci annotated as Alu repetitive elements. Alu elements are members of the repeat subfamily of short interspersed nuclear elements (SINE) and were reported to be transcribed upon stress stimulation. While EBV infection significantly up-regulated expression of Alu-derived RNA transcripts, no significant increase in expression of these transcripts was observed under additional tested stress conditions. By employing deep sequencing followed by custom microchip analysis, we identified six novel differentially expressed ncRNAs as well as significantly increased expression levels of Alu-derived RNA transcripts. These transcripts might be involved in crucial functions upon infection by EBV. 5 biological replica of non-infected BL2 samples were compared to 5 biological replica of LCL 197/2 EBV immortalized samples
Project description:Upon Epstein-Barr virus (EBV) infection of human B lymphocytes non-coding RNAs (ncRNAs) regulate expression of viral and cellular genes. In this study, we generated a specialized cDNA library from EBV-immortalized cells and subjected it to deep sequencing. We identified 631 unique ncRNA genes, comprised of 321 potential novel differentially expressed ncRNA candidates. Subsequently, we investigated differential expression of known and potential novel ncRNA candidates by custom-designed microchips by comparing expression of ncRNA genes of EBV-immortalized versus non-infected control cells. Among the differentially expressed candidates from chip analysis, differential expression of six novel ncRNA candidates was verified by northern blot analysis. In addition, microchip analysis resulted in observation of increased expression levels of a significant number of potential ncRNA candidates that were preferentially derived from genomic loci annotated as Alu repetitive elements. Alu elements are members of the repeat subfamily of short interspersed nuclear elements (SINE) and were reported to be transcribed upon stress stimulation. While EBV infection significantly up-regulated expression of Alu-derived RNA transcripts, no significant increase in expression of these transcripts was observed under additional tested stress conditions. By employing deep sequencing followed by custom microchip analysis, we identified six novel differentially expressed ncRNAs as well as significantly increased expression levels of Alu-derived RNA transcripts. These transcripts might be involved in crucial functions upon infection by EBV. Overall design: 5 biological replica of non-infected BL2 samples were compared to 5 biological replica of LCL 197/2 EBV immortalized samples
Project description:Epstein-Barr virus (EBV) infection of human B cells requires the presence of non-coding RNAs (ncRNAs), which regulate expression of viral and host genes. To identify differentially expressed regulatory ncRNAs involved in EBV infection, a specialized cDNA library, enriched for ncRNAs derived from EBV-infected cells, was subjected to deep-sequencing. From the deep-sequencing analysis, we generated a custom-designed ncRNA-microchip to investigate differential expression of ncRNA candidates. By this approach, we identified 25 differentially expressed novel host-encoded ncRNA candidates in EBV-infected cells, comprised of six non-repeat-derived and 19 repeat-derived ncRNAs. Upon EBV infection of B cells, we also observed increased expression levels of oncogenic miRNAs mir-221 and mir-222, which might contribute to EBV-related tumorigenesis, as well as decreased expression levels of RNase P RNA, a ribozyme involved in tRNA maturation. Thus, in this study we demonstrate that our ncRNA-microchip approach serves as a powerful tool to identify novel differentially expressed ncRNAs acting as potential regulators of gene expression during EBV infection.
Project description:Morbidity and mortality of immunocompromised patients are increased by primary infection with or reactivation of Epstein-Barr virus (EBV), possibly triggering EBV+ post-transplant lymphoproliferative disease (PTLD). Adoptive transfer of EBV-specific cytotoxic T cells (EBV-CTLs) promises a non-toxic immunotherapy to effectively prevent or treat these complications. To improve immunotherapy and immunomonitoring this study aimed at identifying and evaluating naturally processed and presented HLA-A*03:01-restricted EBV-CTL epitopes as immunodominant targets. More than 15000 peptides were sequenced from EBV-immortalized B cells transduced with soluble HLA-A*03:01, sorted using different epitope prediction tools and eleven candidates were preselected. T2 and Flex-T peptide-binding and dissociation assays confirmed the stability of peptide-MHC complexes. Their immunogenicity and clinical relevance were evaluated by assessing the frequencies and functionality of EBV-CTLs in healthy donors (n > 10) and EBV+ PTLD-patients (n = 5) by multimer staining, Eli- and FluoroSpot assays. All eleven peptides elicited EBV-CTL responses in the donors. Their clinical applicability was determined by small-scale T-cell enrichment using Cytokine Secretion Assay and immunophenotyping. Mixtures of these peptides when added to the EBV Consensus pool revealed enhanced stimulation and enrichment efficacy. These EBV-specific epitopes broadening the repertoire of known targets will improve manufacturing of clinically applicable EBV-CTLs and monitoring of EBV-specific T-cell responses in patients.
Project description:Alu retroelements, whose retrotransposition requires prior transcription by RNA polymerase III to generate Alu RNAs, represent the most numerous non-coding RNA (ncRNA) gene family in the human genome. Alu transcription is generally kept to extremely low levels by tight epigenetic silencing, but it has been reported to increase under different types of cell perturbation, such as viral infection and cancer. Alu RNAs, being able to act as gene expression modulators, may be directly involved in the mechanisms determining cellular behavior in such perturbed states. To directly address the regulatory potential of Alu RNAs, we generated IMR90 fibroblasts and HeLa cell lines stably overexpressing two slightly different Alu RNAs, and analyzed genome-wide the expression changes of protein-coding genes through RNA-sequencing. Among the genes that were upregulated or downregulated in response to Alu overexpression in IMR90, but not in HeLa cells, we found a highly significant enrichment of pathways involved in cell cycle progression and mitotic entry. Accordingly, Alu overexpression was found to promote transition from G1 to S phase, as revealed by flow cytometry. Therefore, increased Alu RNA may contribute to sustained cell proliferation, which is an important factor of cancer development and progression.
Project description:Gene expression changes in L. monocytogenes EGDe during lag-phase associated cold acclimation were succesfully defined through expression profiling The gene expression profiles of L. monocytogenes EGD-e cells that underwent cold acclimation during lag phase were analyzed in a genome-wide microarray assay with a total of 2847 genes, were the resulting significantly regulated genes were splitted in two groups (up-and down-regulated)
Project description:Epstein-Barr virus (EBV) is implicated in the pathogenesis of human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OSCC). EBV-associated cancers harbor a latent EBV infection characterized by a lack of viral replication and the expression of viral oncogenes. Cellular changes promoted by HPV are comparable to those shown to facilitate EBV latency, though whether HPV-positive cells support a latent EBV infection has not been demonstrated. Using a model of direct EBV infection into HPV16-immortalized tonsillar cells grown in organotypic raft culture, we showed robust EBV replication in HPV-negative rafts but little to no replication in HPV-immortalized rafts. The reduced EBV replication was independent of immortalization, as human telomerase-immortalized normal oral keratinocytes supported robust EBV replication. Furthermore, we observed reduced EBV lytic gene expression and increased expression of EBER1, a noncoding RNA highly expressed in latently infected cells, in the presence of HPV. The use of human foreskin keratinocyte rafts expressing the HPV16 E6 and/or E7 oncogene(s) (HPV E6 and E7 rafts) showed that E7 was sufficient to reduce EBV replication. EBV replication is dependent upon epithelial differentiation and the differentiation-dependent expression of the transcription factors KLF4 and PRDM1. While KLF4 and PRDM1 levels were unaltered, the expression levels of KLF4 transcriptional targets, including late differentiation markers, were reduced in HPV E6 and E7 rafts compared to their levels in parental rafts. However, the HPV E7-mediated block in EBV replication correlated with delayed expression of early differentiation markers. Overall, this study reveals an HPV16-mediated block in EBV replication, through E7, that may facilitate EBV latency and long-term persistence in the tumor context.IMPORTANCE Using a model examining the establishment of EBV infection in HPV-immortalized tissues, we showed an HPV-induced interruption of the normal EBV life cycle reminiscent of a latent EBV infection. Our data support the notion that a persistent EBV epithelial infection depends upon preexisting cellular alterations and suggest the ability of HPV to promote such changes. More importantly, these findings introduce a model for how EBV coinfection may influence HPV-positive (HPV-pos) OSCC pathogenesis. Latently EBV-infected epithelial cells, as well as other EBV-associated head-and-neck carcinomas, exhibit oncogenic phenotypes commonly seen in HPV-pos OSCC. Therefore, an HPV-induced shift in the EBV life cycle toward latency would not only facilitate EBV persistence but also provide additional viral oncogene expression, which can contribute to the rapid progression of HPV-pos OSCC. These findings provide a step toward defining a role for EBV as a cofactor in HPV-positive oropharyngeal tumors.
Project description:Several methods exist for predicting non-coding RNA (ncRNA) genes in Escherichia coli (E.coli). In addition to about sixty known ncRNA genes excluding tRNAs and rRNAs, various methods have predicted more than thousand ncRNA genes, but only 95 of these candidates were confirmed by more than one study. Here, we introduce a new method that uses automatic discovery of sequence patterns to predict ncRNA genes. The method predicts 135 novel candidates. In addition, the method predicts 152 genes that overlap with predictions in the literature. We test sixteen predictions experimentally, and show that twelve of these are actual ncRNA transcripts. Six of the twelve verified candidates were novel predictions. The relatively high confirmation rate indicates that many of the untested novel predictions are also ncRNAs, and we therefore speculate that E.coli contains more ncRNA genes than previously estimated.
Project description:We report a biosensing platform for viral load measurement through electrical sensing of viruses on a flexible plastic microchip with printed electrodes. Point-of-care (POC) viral load measurement is of paramount importance with significant impact on a broad range of applications, including infectious disease diagnostics and treatment monitoring specifically in resource-constrained settings. Here, we present a broadly applicable and inexpensive biosensing technology for accurate quantification of bioagents, including viruses in biological samples, such as plasma and artificial saliva, at clinically relevant concentrations. Our microchip fabrication is simple and mass-producible as we print microelectrodes on flexible plastic substrates using conductive inks. We evaluated the microchip technology by detecting and quantifying multiple Human Immunodeficiency Virus (HIV) subtypes (A, B, C, D, E, G, and panel), Epstein-Barr Virus (EBV), and Kaposi's Sarcoma-associated Herpes Virus (KSHV) in a fingerprick volume (50 µL) of PBS, plasma, and artificial saliva samples for a broad range of virus concentrations between 10(2) copies/mL and 10(7) copies/mL. We have also evaluated the microchip platform with discarded, de-identified HIV-infected patient samples by comparing our microchip viral load measurement results with reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) as the gold standard method using Bland-Altman Analysis.
Project description:Transcriptome of A. fumigatus shifted from ammoniumtartrate to different nitrogen sources and incubated for a defined time was compared. After 16h preculture, the fungus was transferred into fresh medium containing ammonium tartrate, sodium nitrate, proline or bsa as nitrogen source. After 1h, fungus was reisolated, RNA was prepared from fungus, transcriptome was assessed and used for further analysis. Ammoniumtartrate, sodiumnitrate, BSA and proline as nitrogen sources, 2 biological replicates for each source. A. fumigatus liquid media shifts were performed according to ref. (Narendja et al.,2002) with minor modifications: 200 ml minimal medium base with 5 mM ammonium tartrate was inoculated with 10^8 conidia freshly harvested. A. fumigatus ATCC 46645 conidia were grown at 37°C and 150 rpm for 16 hours. This pre-culture was then harvested, washed liberally with sterile saline and divided into mycelial masses of equal size on a sterile surface. The portions were then added to 100 ml of minimal medium base without nitrogen source. When a defined carbon source was needed, 1% glucose was added. Flasks were incubated for 20 min at 37°C. Thereafter, one of the following sterile nitrogen sources was added: ammonium tartrate to a final concentration of 5 mM, Sodiumnitrate to a final concentration of 10 mM, 1 g proline suspended in 2 ml minimal medium base, or 0.5 g BSA (Albumin Fraktion V, Roth), suspended in 15 ml minimal medium base. The cultures were incubated for another 60 minutes, harvested by filtering through Miracloth, snap frozen in liquid nitrogen, and ground using a cooled mortar to obtain a fine powder.
Project description:EBV causes B lymphomas and undifferentiated nasopharyngeal carcinoma (NPC). Although the mechanisms by which EBV infects B lymphocytes have been extensively studied, investigation of the mechanisms by which EBV infects nasopharyngeal epithelial cells (NPECs) has only recently been enabled by the successful growth of B lymphoma Mo-MLV insertion region 1 homolog (BMI1)-immortalized NPECs in vitro and the discovery that neuropilin 1 expression positively affects EBV glycoprotein B (gB)-mediated infection and tyrosine kinase activations in enhancing EBV infection of BMI1-immortalized NPECs. We have now found that even though EBV infected NPECs grown as a monolayer at extremely low efficiency (<3%), close to 30% of NPECs grown as sphere-like cells (SLCs) were infected by EBV. We also identified nonmuscle myosin heavy chain IIA (NMHC-IIA) as another NPEC protein important for efficient EBV infection. EBV gH/gL specifically interacted with NMHC-IIA both in vitro and in vivo. NMHC-IIA densely aggregated on the surface of NPEC SLCs and colocalized with EBV. EBV infection of NPEC SLCs was significantly reduced by NMHC-IIA siRNA knock-down. NMHC-IIA antisera also efficiently blocked EBV infection. These data indicate that NMHC-IIA is an important factor for EBV NPEC infection.