BackgroundMice lacking the type I interferon receptor (IFNAR−/− mice) reproduce relevant aspects of Crimean-Congo hemorrhagic fever (CCHF) in humans, including liver damage. We aimed at characterizing the liver pathology in CCHF virus-infected IFNAR−/− mice by immunohistochemistry and employed the model to evaluate the antiviral efficacy of ribavirin, arbidol, and T-705 against CCHF virus.Methodology/Principal FindingsCCHF virus-infected IFNAR−/− mice died 2–6 days post infection with elevated aminotransferase levels and high virus titers in blood and organs. Main pathological alteration was acute hepatitis with extensive bridging necrosis, reactive hepatocyte proliferation, and mild to moderate inflammatory response with monocyte/macrophage activation. Virus-infected and apoptotic hepatocytes clustered in the necrotic areas. Ribavirin, arbidol, and T-705 suppressed virus replication in vitro by ≥3 log units (IC50 0.6–2.8 µg/ml; IC90 1.2–4.7 µg/ml). Ribavirin [100 mg/(kg×d)] did not increase the survival rate of IFNAR−/− mice, but prolonged the time to death (p<0.001) and reduced the aminotransferase levels and the virus titers. Arbidol [150 mg/(kg×d)] had no efficacy in vivo. Animals treated with T-705 at 1 h [15, 30, and 300 mg/(kg×d)] or up to 2 days [300 mg/(kg×d)] post infection survived, showed no signs of disease, and had no virus in blood and organs. Co-administration of ribavirin and T-705 yielded beneficial rather than adverse effects.Conclusions/SignificanceActivated hepatic macrophages and monocyte-derived cells may play a role in the proinflammatory cytokine response in CCHF. Clustering of infected hepatocytes in necrotic areas without marked inflammation suggests viral cytopathic effects. T-705 is highly potent against CCHF virus in vitro and in vivo. Its in vivo efficacy exceeds that of the current standard drug for treatment of CCHF, ribavirin.

The N terminus of arenavirus L protein contains an endonuclease presumably involved in "cap snatching." Here, we employed the Lassa virus replicon system to map other L protein sites that might be involved in this mechanism. Residues Phe-1979, Arg-2018, Phe-2071, Asp-2106, Trp-2173, Tyr-2179, Arg-2200, and Arg-2204 were important for viral mRNA synthesis but dispensable for genome replication. Thus, the C terminus of L protein is involved in the mRNA synthesis process, potentially by mediating cap binding. L assa virus is a segmented negative-strand RNA virus of the family Arenaviridae causing hemorrhagic fever in humans. The genome consists of two single-stranded RNA segments, each containing two genes in opposite directions (1). The S RNA segment encodes the nucleoprotein (NP) and the glycoprotein precursor. The L RNA encodes the small matrix protein Z (2, 3) and the 200-kDa L protein (4). NP and L protein are the minimal viral trans-acting factors required for replication and transcription of the genome (5-7). L protein mediates the synthesis of two RNA species, mRNA terminating in the intergenic region and noncapped genomic or antigenomic RNA representing a full-length copy of the genome (8, 9). The central domain of L protein harbors the RNA-dependent RNA polymerase (RdRp) (10)(11)(12)(13)(14), and the N terminus contains an endonuclease essential for transcription (15, 16). The latter presumably cleaves off from cellular mRNAs the cap structure with 4 to 5 nucleotides, which serves as a primer for viral mRNA synthesis (9,17,18). Influenza virus, the prototype of "cap-snatching" viruses, expresses a cap-binding protein (PB2) (19) in addition to an endonuclease (PA) (20,21). Assuming the cap-snatching mechanism in arenaviruses corresponds to that in influenza virus, it is tempting to speculate that the L protein also contains a cap-binding domain. We have conducted a mutagenesis study to identify residues that might be involved in cap binding. MATERIALS AND METHODSThe experiments were performed in the context of the T7 RNA polymerase-based Lassa virus replicon system essentially as described previously (5, 14, 16). In brief, L gene mutants were generated by mutagenic PCR using pCITE-L as a template. The PCR products containing the functional cassette for expression of mutant L protein were purified, quantified spectrophotometrically, and used for transfection without prior cloning. As the Phusion polymerase used for PCR has an extremely low error rate (22), more than 95% of the amplified L genes are predictably free of random polymerization errors (23). The presence of the desired artificial mutation was ascertained by sequencing. BSR-T7/5 cells stably expressing T7 RNA polymerase (24) were transfected per well of a 24-well plate with 250 ng of minigenome expressing Renilla luciferase (Ren-Luc), 250 ng of L gene PCR product, 250 ng of pCITE-NP expressing NP, and 10 ng of pCITE-FF-luc expressing firefly luciferase as an internal transfection control. One day after transfection, total RNA was purified for Nort...

Overexposure to ultraviolet (UV) radiation is the main modifiable risk factor for skin cancer. The Global Solar Ultraviolet Index (UVI) was introduced as a tool to visualize the intensity of UV radiation on a certain day, which should enable and encourage people to take appropriate protective measures. The ‘low’ exposure category of the UVI, defined by a rounded UVI value of 0, 1 or 2, was linked to the health message ‘No protection required’ by the World Health Organization and partner organizations. However, published evidence corroborating this advice is not available. To evaluate the erythemal risk of low UVI days, we analyzed 14,431 daily time series of ambient erythemal irradiance data measured at nine stations of the German solar UV monitoring network during the years 2007–2016. We analyzed the proportion of days in the sample for which ambient erythemal doses calculated for various time intervals exceed average minimal erythemal doses (MEDs) of the Fitzpatrick skin phototypes I–VI to assess the potential for erythema arising from sun exposure on days with low UVI values. Additionally, we calculated for each day the minimum exposure duration needed to receive one MED. Our results indicate that on days with a UVI value of 0, risk of erythema is indeed negligible. Conversely, the abovementioned health message appears misleading when melano-compromised individuals (skin type I and II) spend more than 1.5 hours outdoors on days with a UVI value of 2. Under rare circumstances of prolonged exposure, MEDs of the two most sensitive skin types can also be exceeded even on days with a UVI value of 1. Hence, current WHO guidance for sun protection on days with low UVI values needs reconsideration.

BackgroundPrevious studies have shown that class-I histone deacetylase (HDAC) 8 mRNA is upregulated in urothelial cancer tissues and urothelial cancer cell lines compared to benign controls. Using urothelial cancer cell lines we evaluated whether specific targeting of HDAC8 might be a therapeutic option in bladder cancer treatment.MethodsWe conducted siRNA-mediated knockdown and specific pharmacological inhibition of HDAC8 with the three different inhibitors compound 2, compound 5, and compound 6 in several urothelial carcinoma cell lines with distinct HDAC8 expression profiles. Levels of HDAC and marker proteins were determined by western blot analysis and mRNA levels were measured by quantitative real-time PCR. Cellular effects of HDAC8 suppression were analyzed by ATP assay, flow cytometry, colony forming assay and migration assay.ResultsEfficient siRNA-mediated knockdown of HDAC8 reduced proliferation up to 45%. The HDAC8 specific inhibitors compound 5 and compound 6 significantly reduced viability of all urothelial cancer cell lines (IC50 9 – 21 μM). Flow cytometry revealed only a slight increase in the sub-G1 fraction indicating a limited induction of apoptosis. Expression of thymidylate synthase was partly reduced; PARP-cleavage was not detected. The influence of the pharmacological inhibition on clonogenic growth and migration show a cell line- and inhibitor-dependent reduction with the strongest effects after treatment with compound 5 and compound 6.ConclusionsDeregulation of HDAC8 is frequent in urothelial cancer, but neither specific pharmacological inhibition nor siRNA-mediated knockdown of HDAC8 impaired viability of urothelial cancer cell lines in a therapeutic useful manner. Accordingly, HDAC8 on its own is not a promising drug target in bladder cancer.