Epstein-Barr Viruses (EBVs) Deficient in EBV-Encoded RNAs Have Higher Levels of Latent Membrane Protein 2 RNA Expression in Lymphoblastoid Cell Lines and Efficiently Establish Persistent Infections in Humanized Mice.

Functions of Epstein-Barr virus (EBV)-encoded RNAs (EBERs) were tested in lymphoblastoid cell lines containing EBER mutants of EBV. Binding of EBER1 to ribosomal protein L22 (RPL22) was confirmed. Deletion of EBER1 or EBER2 correlated with increased levels of cytoplasmic EBV LMP2 RNA and with small effects on specific cellular microRNA (miRNA) levels, but protein levels of LMP1 and LMP2A were not affected. Wild-type EBV and EBER deletion EBV had approximately equal abilities to infect immunodeficient mice reconstituted with a human hematopoietic system.

C-terminal region of EBNA-2 determines the superior transforming ability of type 1 Epstein-Barr virus by enhanced gene regulation of LMP-1 and CXCR7.

Type 1 Epstein-Barr virus (EBV) strains immortalize B lymphocytes in vitro much more efficiently than type 2 EBV, a difference previously mapped to the EBNA-2 locus. Here we demonstrate that the greater transforming activity of type 1 EBV correlates with a stronger and more rapid induction of the viral oncogene LMP-1 and the cell gene CXCR7 (which are both required for proliferation of EBV-LCLs) during infection of primary B cells with recombinant viruses. Surprisingly, although the major sequence differences between type 1 and type 2 EBNA-2 lie in N-terminal parts of the protein, the superior ability of type 1 EBNA-2 to induce proliferation of EBV-infected lymphoblasts is mostly determined by the C-terminus of EBNA-2. Substitution of the C-terminus of type 1 EBNA-2 into the type 2 protein is sufficient to confer a type 1 growth phenotype and type 1 expression levels of LMP-1 and CXCR7 in an EREB2.5 cell growth assay. Within this region, the RG, CR7 and TAD domains are the minimum type 1 sequences required. Sequencing the C-terminus of EBNA-2 from additional EBV isolates showed high sequence identity within type 1 isolates or within type 2 isolates, indicating that the functional differences mapped are typical of EBV type sequences. The results indicate that the C-terminus of EBNA-2 accounts for the greater ability of type 1 EBV to promote B cell proliferation, through mechanisms that include higher induction of genes (LMP-1 and CXCR7) required for proliferation and survival of EBV-LCLs.

Cellular gene expression that correlates with EBER expression in Epstein-Barr Virus-infected lymphoblastoid cell lines.

Novel Epstein-Barr Virus (EBV) strains with deletion of either EBER1 or EBER2 and corresponding revertant viruses were constructed and used to infect B lymphocytes to make lymphoblastoid cell lines (LCLs). The LCLs were used in microarray expression profiling to identify genes whose expression correlates with the presence of EBER1 or EBER2. Functions of regulated genes identified in the microarray analysis include membrane signaling, regulation of apoptosis, and the interferon/antiviral response. Although most emphasis has previously been given to EBER1 because it is more abundant than EBER2, the differences in cell gene expression were greater with EBER2 deletion. In this system, deletion of EBER1 or EBER2 had little effect on the EBV transformation frequency of primary B cells or the growth of the resulting LCLs. Using the recombinant viruses and novel EBER expression vectors, the nuclear redistribution of rpL22 protein by EBER1 in 293 cells was confirmed, but in LCLs almost all of the cells had a predominantly cytoplasmic expression of this ribosomal protein, which was not detectably changed by EBER1. The changes in LCL gene expression identified here will provide a basis for identifying the mechanisms of action of EBER RNAs.

Systematic reviews of economic burden and health-related quality of life in patients with acute myeloid leukemia.

BACKGROUND: Acute myeloid leukemia (AML) is a rare hematologic malignancy largely affecting older adults. Comorbidities may compromise fitness and eligibility for high-intensity chemotherapy (HIC). This study presents the results of two systematic reviews (SRs) assessing (1) the impact of AML and current treatments on health-related quality of life (HRQoL), and (2) the economic burden and cost drivers of AML in patients who are ineligible for HIC. METHODS: Electronic searches (MEDLINE, EMBASE, EconLit, Cochrane library) were supplemented with manual searching of conference, utility, and HTA databases. All studies reporting HRQoL or economic data for patients with AML who were ineligible for HIC were included. RESULTS: The HRQoL SR included ten studies. Patients with AML have lower baseline HRQoL than other cancer patients or the general population, and those receiving lower intensity treatment have lower HRQoL than those eligible for HIC. Low baseline HRQoL predicts poor outcomes, and treatment had variable effects on HRQoL. The economic burden SR included nine studies. Medical costs varied widely, reflecting the heterogeneity of AML. Hospitalization is a key cost driver in AML treatment but was largely not considered in cost studies. Medical resource utilization comprised drug acquisition, drug administration, disease monitoring tests, transfusions, adverse event management, supportive care/monitoring costs and terminal care. CONCLUSION: As new drugs emerge that extend survival, assessment of HRQoL will be important to evaluate the quality of that survival. Cost data, driven by transfusions and hospitalization, will be important to evaluate the economic value of new treatments.

The Legionella pneumophila response regulator LqsR promotes host cell interactions as an element of the virulence regulatory network controlled by RpoS and LetA.

Legionella pneumophila is an opportunistic human pathogen that replicates within environmental amoebae including Acanthamoeba castellanii and Dictyostelium discoideum. The Icm/Dot type IV secretion system promotes phagocytosis and intracellular replication of L. pneumophila in an endoplasmic reticulum-derived 'Legionella-containing vacuole' (LCV). L. pneumophila adopts a biphasic life cycle consisting of a replicative growth phase and a transmissive (stationary) phase, the latter of which is characterized by the preferential expression of genes required for motility and virulence. A bioinformatic analysis of the L. pneumophila genome revealed a gene cluster homologous to the Vibrio cholerae cqsAS genes, encoding a putative quorum sensing autoinducer synthase (lqsA) and a sensor kinase (lqsS), which flank a novel response regulator (lqsR). We report here that an L. pneumophila lqsR deletion mutant grew in broth with the same rate as wild-type bacteria, but entered the replicative growth phase earlier. Overexpression of lqsR led to an elongated morphology of the bacteria. The lqsR mutant strain was found to be more salt-resistant and impaired for intracellular growth in A. castellanii, D. discoideum and macrophages, formation of the ER-derived LCV and toxicity. Moreover, L. pneumophila lacking LqsR, as well as strains lacking the stationary sigma factor RpoS or the two-component response regulator LetA, were phagocytosed less efficiently by A. castellanii, D. discoideum or macrophages. The expression of lqsR was dependent on RpoS and, to a lesser extent, also on LetA. DNA microarray experiments revealed that lqsR regulates the expression of genes involved in virulence, motility and cell division, consistent with a role for LqsR in the transition from the replicative to the transmissive (virulent) phase. Our findings indicate that LqsR is a novel pleiotropic regulator involved in RpoS- and LetA-controlled interactions of L. pneumophila with phagocytes.