An Epstein-Barr virus–encoded microRNA targets PUMA to promote host cell survival

Epstein-Barr virus (EBV) is a herpesvirus associated with nasopharyngeal carcinoma (NPC), gastric carcinoma (GC), and other malignancies. EBV is the first human virus found to express microRNAs (miRNAs), the functions of which remain largely unknown. We report on the regulation of a cellular protein named p53 up-regulated modulator of apoptosis (PUMA) by an EBV miRNA known as miR-BART5, which is abundantly expressed in NPC and EBV-GC cells. Modulation of PUMA expression by miR-BART5 and anti–miR-BART5 oligonucleotide was demonstrated in EBV-positive cells. In addition, PUMA was found to be significantly underexpressed in ∼60% of human NPC tissues. Although expression of miR-BART5 rendered NPC and EBV-GC cells less sensitive to proapoptotic agents, apoptosis can be triggered by depleting miR-BART5 or inducing the expression of PUMA. Collectively, our findings suggest that EBV encodes an miRNA to facilitate the establishment of latent infection by promoting host cell survival

Carboxyl-terminal truncated HBx regulates a distinct microRNA transcription program in Hepatocellular carcinoma development

Background: The biological pathways and functional properties by which misexpressed microRNAs (miRNAs) contribute to liver carcinogenesis have been intensively investigated. However, little is known about the upstream mechanisms that deregulate miRNA expressions in this process. In hepatocellular carcinoma (HCC), hepatitis B virus (HBV) X protein (HBx), a transcriptional trans-activator, is frequently expressed in truncated form without carboxyl-terminus but its role in miRNA expression and HCC development is unclear. Methods: Human non-tumorigenic hepatocytes were infected with lentivirus-expressing full-length and carboxyl-terminal truncated HBx (Ct-HBx) for cell growth assay and miRNA profiling. Chromatin immunoprecipitation microarray was performed to identify the miRNA promoters directly associated with HBx. Direct transcriptional control was verified by luciferase reporter assay. The differential miRNA expressions were further validated in a cohort of HBV-associated HCC tissues using real-time PCR. Results: Hepatocytes expressing Ct-HBx grew significantly faster than the full-length HBx counterparts. Ct-HBx decreased while full-length HBx increased the expression of a set of miRNAs with growth-suppressive functions. Interestingly, Ct-HBx bound to and inhibited the transcriptional activity of some of these miRNA promoters. Notably, some of the examined repressed-miRNAs (miR-26a, -29c, -146a and -190) were also significantly down-regulated in a subset of HCC tissues with carboxyl-terminal HBx truncation compared to their matching non-tumor tissues, highlighting the clinical relevance of our data. Conclusion: Our results suggest that Ct-HBx directly regulates miRNA transcription and in turn promotes hepatocellular proliferation, thus revealing a viral contribution of miRNA deregulation during hepatocarcinogenesis. © 2011 Yip et al.published_or_final_versio

Rationalisation and Validation of an Acrylamide-Free Procedure in Three-Dimensional Histological Imaging

201810_a bcmapublished_fina

Meta-analysis Followed by Replication Identifies Loci in or near CDKN1B, TET3, CD80, DRAM1, and ARID5B as Associated with Systemic Lupus Erythematosus in Asians

Systemic lupus erythematosus (SLE) is a prototype autoimmune disease with a strong genetic involvement and ethnic differences. Susceptibility genes identified so far only explain a small portion of the genetic heritability of SLE, suggesting that many more loci are yet to be uncovered for this disease. In this study, we performed a meta-analysis of genome-wide association studies on SLE in Chinese Han populations and followed up the findings by replication in four additional Asian cohorts with a total of 5,365 cases and 10,054 corresponding controls. We identified genetic variants in or near CDKN1B, TET3, CD80, DRAM1, and ARID5B as associated with the disease. These findings point to potential roles of cell-cycle regulation, autophagy, and DNA demethylation in SLE pathogenesis. For the region involving TET3 and that involving CDKN1B, multiple independent SNPs were identified, highlighting a phenomenon that might partially explain the missing heritability of complex diseases

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Cytotoxic pro-drug therapy approach for malignant melanoma of soft parts

Malignant Melanoma of Soft Parts (MMSP) is an aggressive tumor of soft tissue. This tumor occurs due to the function of dominant oncogene named EWS/ATFl, which is created by the chromosomal translocation fusing of Ewings Sarcoma oncogene (EWS) to the DNA binding (bZIP) domain of the cellular transcription factor ATFl . In normal cells, ATFl is directly phosphorylated by protein kinase A (PKA) and functions as a cAMP regulated transcriptional activator, upon directly binding to ATFl binding sites present in cAMP inducible promoter. In contrast, when assayed in a transient transfection, the EWS/ATFl fusion protein is a strong constitutive activator of several cAMP-inducible promoters, including the somatostatin promoter. Based on the transcriptional and tumor specific properties of EWS/ATFl, my project aims to develop a cytotoxic gene therapy for MMSP, using the somatostatin promoter to achieve toxic gene expression specifically in tumor cells. In addition, we evaluated recombinant adenovirus as a gene delivery system for MMSP cells. The major findings are as follows, the MMSP-derived cell line, DTCl (D7ltk cells) expressing the herpes simplex virus thymidine kinase (HSV-tk gene) under the control of the somatostatin promoter showed high sensitivity to ganciclovir (GCV). The sensitivity was dependent on the ATF binding site present in the somatostatin promoter indicating that it is EWS/ATFl dependent. Several recombinant adenoviruses containing EWS/ATFl responsive promoters were constructed and used to infect two MMSP derived cell lines, DTCl and Su-ccs-1. Surprisingly, the viral borne promoters were not responsive to EWS/ATFl in either cell type. These promoters could be activated by adenovirus ElA protein, indicating that the promoters were successfully delivered to the nucleus of MMSP cells and can be activated, at least by ElA. In conclusion, our results show that the somatostatin promoter can be exploited as tumor specific promoter for cytotoxic pro-drug gene therapy in MMSP, using HSV-tk as the cytotoxic gene and GCV as a pro-drug. However, the commonly used recombinant adenovirus system for cytotoxic gene delivery may not be useful in MMSP cells due to loss of responsiveness to the endogenous EWS/ATFl protein

Slam protein is required for <i>slam</i> RNA localization.

<p><b>(A)</b> Experimental scheme. Wild-type embryos were injected with synthetic <i>slam</i> mRNAs. After incubation, embryos were imaged or fixed and stained. <b>(B)</b> Fluorescently (schematically indicated by *) labeled <i>slam</i> RNA. Images from time-lapse recording. Arrows point to RNA at the FC. <b>(C)</b> Crossing scheme for generation of <i>slam</i> deficient (Δ<i>slam</i>) embryos. Half of the embryos receive the Δ<i>slam</i> allele and are maternally and zygotically deficient for <i>slam</i>; the other half receives a wild-type allele from the male and is zygotically rescued. <b>(D)</b> <i>GFP-stop-slam</i> RNA was injected into embryos from <i>slam</i> germ line clones. Fixed embryos were stained for the injected <i>GFP-stop-slam</i> RNA (grey/red), Slam protein (grey/green), and DNA (blue). Inset: areas marked by dashed box are shown at 2.25× magnification. Scale bars = 10 μm.</p

Modulation of LMP2A Expression by a Newly Identified Epstein-Barr Virus-Encoded MicroRNA miR-BART2212

Infection with the Epstein-Barr virus (EBV) is a strong predisposing factor in the development of nasopharyngeal carcinoma (NPC). Many viral gene products including EBNA1, LMP1, and LMP2 have been implicated in NPC tumorigenesis, although the de novo control of these viral oncoproteins remains largely unclear. The recent discovery of EBV-encoded viral microRNA (miRNA) in lymphoid malignancies has prompted us to examine the NPC-associated EBV miRNA. Using large-scale cloning analysis on EBV-positive NPC cells, two novel EBV miRNA, now named miR-BART21 and miR-BART22, were identified. These two EBV-encoded miRNA are abundantly expressed in most NPC samples. We found two nucleotide variations in the primary transcript of miR-BART22, which we experimentally confirmed to augment its biogenesis in vitro and thus may underline the high and consistent expression of miR-BART22 in NPC tumors. More importantly, we determined that the EBV latent membrane protein 2A (LMP2A) is the putative target of miR-BART22. LMP2A is a potent immunogenic viral antigen that is recognized by the cytotoxic T cells; down-modulation of LMP2A expression by miR-BART22 may permit escape of EBV-infected cells from host immune surveillance. Taken together, we demonstrated that two newly identified EBV-encoded miRNA are highly expressed in NPC. Specific sequence variations on the prevalent EBV strain in our locality might contribute to the higher miR-BART22 expression level in our NPC samples. Our findings emphasize the role of miR-BART22 in modulating LMP2A expression, which may facilitate NPC carcinogenesis by evading the host immune response