Medulloblastomas are the most common malignant brain tumors in children. They express high levels of COX-2 and produce PGE 2 , which stimulates tumor cell proliferation. Human cytomegalovirus (HCMV) is prevalent in the human population and encodes proteins that provide immune evasion strategies and promote oncogenic transformation and oncomodulation. In particular, HCMV induces COX-2 expression; STAT3 phosphorylation; production of PGE 2 , vascular endothelial growth factor, and IL-6; and tumor formation in vivo. Here, we show that a large proportion of primary medulloblastomas and medulloblastoma cell lines are infected with HCMV and that COX-2 expression, along with PGE 2 levels, in tumors is directly modulated by the virus. Our analysis indicated that both HCMV immediate-early proteins and late proteins are expressed in the majority of primary medulloblastomas. Remarkably, all of the human medulloblastoma cell lines that we analyzed contained HCMV DNA and RNA and expressed HCMV proteins at various levels in vitro. When engrafted into immunocompromised mice, human medulloblastoma cells induced expression of HCMV proteins. HCMV and COX-2 expression correlated in primary tumors, cell lines, and medulloblastoma xenografts. The antiviral drug valganciclovir and the specific COX-2 inhibitor celecoxib prevented HCMV replication in vitro and inhibited PGE 2 production and reduced medulloblastoma tumor cell growth both in vitro and in vivo. Ganciclovir did not affect the growth of HCMV-negative tumor cell lines. These findings imply an important role for HCMV in medulloblastoma and suggest HCMV as a novel therapeutic target for this tumor.

Human cytomegalovirus (HCMV) is the most common cause of congenital infections in developed countries, with an incidence varying between 0.5 and 2.2% and consequences varying from asymptomatic infection to lethal conditions for the fetus. Infants that are asymptomatic at birth may still develop neurological sequelae, such as hearing loss and mental retardation, at a later age. Infection of neural stem and precursor cells by HCMV and consequent disruption of the proliferation, differentiation, and/or migration of these cells may be the primary mechanism underlying the development of brain abnormalities. In the present investigation, we demonstrate that human neural precursor cells (NPCs) are permissive for HCMV infection, by both the laboratory strain Towne and the clinical isolate TB40, resulting in 55% and 72% inhibition of induced differentiation of human NPCs into neurons, respectively, when infection occurred at the onset of differentiation. This repression of neuronal differentiation required active viral replication and involved the expression of late HCMV gene products. This capacity of HCMV to prevent neuronal differentiation declined within 24 h after initiation of differentiation. Furthermore, the rate of cell proliferation in infected cultures was attenuated. Surprisingly, HCMV-infected cells exhibited an elevated frequency of apoptosis at 7 days following the onset of differentiation, at which time approximately 50% of the cells were apoptotic at a multiplicity of infection of 10. These findings indicate that HCMV has the capacity to reduce the ability of human NPCs to differentiate into neurons, which may offer one explanation for the abnormalities in brain development associated with congenital HCMV infection.

BackgroundInstruments have been developed to facilitate suicide risk assessment. We aimed to evaluate the evidence for these instruments including assessment of risk of bias and diagnostic accuracy for suicide and suicide attempt.MethodsPubMed (NLM), PsycInfo, Embase, Cinahl and the Cochrane Library databases were searched until December 2014. We assessed risk of bias with QUADAS-2. The average sensitivity and specificity of each instrument was estimated and the certainty of the evidence was assessed with GRADE. We considered instruments with a sensitivity > 80% and a specificity > 50% to have sufficient diagnostic accuracy.ResultsThirty-five relevant studies were identified but 14 were considered to have high risk of bias, leaving 21 studies evaluating altogether 15 risk assessment instruments. We could carry out meta-analyses for five instruments. For the outcome suicide attempt SAD PERSONS Scale had a sensitivity of 15% (95% CI 8–24) and specificity of 97% (96–98), and the Manchester Self-Harm Rule (MSHR) a sensitivity of 97% (97–97) and a specificity of 20% (20–21). ReACT, which is a modification of MSHR, had a similar low specificity, as did the Sodersjukhuset Self Harm Rule. For the outcome suicide, the Beck Hopelessness Scale had a sensitivity of 89% (78–95) and specificity of 42% (40–43).ConclusionsMost suicide risk assessment instruments were supported by too few studies to allow for evaluation of accuracy. Among those that could be evaluated, none fulfilled requirements for sufficient diagnostic accuracy.

Human CMV (HCMV) interferes with NK cell functions at various levels. The HCMV glycoprotein UL16 binds some of the ligands recognized by the NK-activating receptor NKG2D, namely UL16-binding proteins (ULBP) 1 and 2 and MHC class I-related chain B, possibly representing another mechanism of viral immune escape. This study addressed the expression and function of these proteins in infected cells. HCMV induced the expression of all three ULBPs, which were predominantly localized in the endoplasmic reticulum of infected fibroblasts together with UL16. However, while at a lower viral dose ULBP1 and 2 surface expression was completely inhibited compared to ULBP3, at a higher viral dose cell surface expression of ULBP1 and ULBP2 was delayed. The induction of ULBPs correlated with an increased dependency on NKG2D for recognition; however, the overall NK sensitivity did not change (suggesting that additional viral mechanisms interfere with NKG2D-independent pathways for recognition). Infection with a UL16 deletion mutant virus resulted in a different pattern compared to the wild type: all three ULBP molecules were induced with similar kinetics at the cell surface, accompanied by a pronounced, entirely NKG2D-dependent increase in NK sensitivity. Together our findings show that upon infection with HCMV, the host cell responds by expression of ULBPs and increased susceptibility to the NKG2D-mediated component of NK cell recognition, but UL16 limits these effects by interfering with the surface expression of ULBP1 and ULBP2.

Human cytomegalovirus (HCMV) is the most common cause of congenital infections in developed countries, with an incidence varying between 0.5-2.2%. Such infection may be the consequence of either a primary infection or reactivation of a latent infection in the mother and the outcome may vary from asymptomatic to severe brain disorders. Moreover, infants that are asymptomatic at the time of birth may still develop neurologic sequelae at a later age. Our hypothesis is that infection of stem cells of the central nervous system by HCMV alters the proliferation, differentiation or migration of these cells, and thereby gives rise to the brain abnormalities observed. We show that infection of human neural precursor cells (NPCs) with the laboratory strain Towne or the clinical isolate TB40 of HCMV suppresses the differentiation of these cells into astrocytes even at an multiplicity of infection (MOI) as low as 0.1 (by 33% and 67%, respectively). This inhibition required active viral replication and the expression of late HCMV proteins. Infection as late as 24 hr after the onset of differentiation, but not after 72 hr, also prevented the maturation of infected cultures. Furthermore, in cultures infected with TB40 (at an MOI of 1), approximately 54% of the cells were apoptotic and cell proliferation was significantly attenuated. Clearly, HCMV can reduce the capacity of NPCs to differentiate into astrocytes and this effect may provide part of the explanation for the abnormalities in brain development associated with congenital HCMV infection.

Human cytomegalovirus (HCMV) has developed multiple strategies to escape immune recognition. Here, we demonstrate that HCMV down-regulates HLA-DR expression in infected interferon ␥ (IFN-␥)-stimulated fibroblasts at 1 day after infection. Decreased HLA-DR expression was not observed on cells infected with an HCMV strain lacking the pp65 gene IntroductionHuman cytomegalovirus (HCMV) belongs to the ␤ herpes family, and a primary infection is followed by latency and/or a persistent infection. 1 Although HCMV infection is usually asymptomatic in healthy individuals, the virus can cause severe morbidity and mortality in immunocompromised patients, eg, patients who have received a transplant and patients with AIDS. T cells play an important role in combating intracellular pathogens. Activation of T cells depends on their ability to recognize foreign peptides associated with either HLA class I (cytotoxic T cells, CTL) or HLA class II molecules (CD4 ϩ T cell). Although HLA class I molecules are expressed by all nucleated cells, HLA class II molecules are present only on antigen-presenting cells, such as dendritic cells, macrophages, and B cells. However, HLA class II expression can be induced on other cells by, for example, interferon ␥ (IFN-␥) stimulation. Both the inducible and the constitutive HLA class II expression is tightly regulated, and multiple proteins are involved in this process. 2 Increased or induced HLA class II expression by IFN-␥ 3 is mediated through activation of the Jak/Stat signaling pathway and transcription of the class II transactivator (CIITA), 4 which initiates HLA class II transcription. Furthermore, several proteins are responsible for controlling the transportation and peptide loading of HLA class II molecules. Three important proteins in this process are HLA-DM, the invariant chain (Ii), and the class II-associated invariant chain peptide (CLIP). Although the invariant chain is involved in the correct folding of the HLA class II complex in the endoplasmic reticulum (ER) and transportation of the complex to the class II compartment (MIIC), prevention of peptide binding in the ER is mediated by CLIP. HLA-DM catalyses the release of CLIP, and the binding of antigenic peptides to the cleft in the HLA class II molecules present in the MIIC. 5 CD4 ϩ T cells play a key role in the early activation of CTL as well as in B-cell activation. HCMV immediately early (IE)-specific CD4 ϩ T cells have been shown to produce cytokines, which inhibit HCMV replication in U373 MG cells, 6 and CD4 ϩ T cells can also control and clear murine CMV (MCMV) infection. 7,8 Thus, immune evasion strategies affecting HLA class II expression and antigen presentation to CD4 ϩ T cells would be of utmost importance for the virus to avoid early immune recognition. Although several different HCMV proteins 9-13 that interfere with HLA class I expression have been identified, the mechanisms and the viral proteins involved in down-regulation of HLA class II molecules on HCMV-infected cells are less characterized. Several studies ...

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Glioblastoma (GBM) is associated with poor prognosis despite aggressive surgical resection, chemotherapy, and radiation therapy. Unfortunately, this standard therapy does not target glioma cancer stem cells (GCSCs), a subpopulation of GBM cells that can give rise to recurrent tumors. GBMs express human cytomegalovirus (HCMV) proteins, and previously we found that the level of expression of HCMV immediate-early (IE) protein in GBMs is a prognostic factor for poor patient survival. In this study, we investigated the relation between HCMV infection of GBM cells and the presence of GCSCs. Primary GBMs were characterized by their expression of HCMV-IE and GCSCs marker CD133 and by patient survival. The extent to which HCMV infection of primary GBM cells induced a GCSC phenotype was evaluated in vitro. In primary GBMs, a large fraction of CD133-positive cells expressed HCMV-IE, and higher co-expression of these two proteins predicted poor patient survival. Infection of GBM cells with HCMV led to upregulation of CD133 and other GSCS markers (Notch1, Sox2, Oct4, Nestin). HCMV infection also promoted the growth of GBM cells as neurospheres, a behavior typically displayed by GCSCs, and this phenotype was prevented by either chemical inhibition of the Notch1 pathway or by treatment with the anti-viral drug ganciclovir. GBM cells that maintained expression of HCMV-IE failed to differentiate into neuronal or astrocytic phenotypes. Our findings imply that HCMV infection induces phenotypic plasticity of GBM cells to promote GCSC features and may thereby increase the aggressiveness of this tumor. GBM is the most prevalent and the most aggressive primary malignancy of the central nervous system in adults. It is a highly vascularized and infiltrating tumor, rarely cured and prone to recurrence. The median duration of survival after diagnosis is less than 15 months, despite aggressive therapy consisting of surgical resection and concomitant radiotherapy and chemotherapy. 1 Surgical resection of GBMs is typically incomplete, as they are located in the brain and are highly infiltrative. Postoperative radiotherapy and chemotherapy fail to eradicate all remaining GBM cells. Thus, a breakthrough in identifying a new treatment option leading to a cure of this disease is still lacking.GBMs contain a subpopulation of highly tumorigenic cells with unlimited capacity for self-renewal that are commonly resistant to standard therapy. Phenotypically and functionally, these cells resemble neural stem cells and, when implanted in immunodeficient mice, can generate new tumors. As a result, they are referred to as glioma cancer initiating cells or glioma cancer stem cells (GCSCs) (reviewed in Lima et al. 2 ).Because of their apparent pivotal role in gliomagenesis and tumor recurrence after therapy, GCSCs are a major focus of research whose ultimate goal is to identify more effective therapies for GBM patients.GCSCs were first identified by their surface expression of CD133, based on the findings that these cells grow as neurospheres under nonadher...