Background: Zinc is an essential micronutrient that impacts host–pathogen interplay at infection. Zinc balances immune responses, and also has a proven direct antiviral action against some viruses. Importantly, zinc deficiency (ZD) is a common condition in elderly and individuals with chronic diseases, two groups with an increased risk for severe severe coronavirus disease 2019 (COVID-19) outcomes. We hypothesize that serum zinc content (SZC) influences COVID-19 disease progression, and thus might represent a useful biomarker. Methods: We ran an observational cohort study with 249 COVID-19 patients admitted in Hospital del Mar. We have studied COVID-19 severity and progression attending to SZC at admission. In parallel, we have studied severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) replication in the Vero E6 cell line modifying zinc concentrations. Findings: Our study demonstrates a correlation between serum zinc levels and COVID-19 outcome. Serum zinc levels lower than 50 µg/dL at admission correlated with worse clinical presentation, longer time to reach stability, and higher mortality. Our in vitro results indicate that low zinc levels favor viral expansion in SARS-CoV-2 infected cells. Interpretation: Low SZC is a risk factor that determines COVID-19 outcome. We encourage performing randomized clinical trials to study zinc supplementation as potential prophylaxis and treatment with people at risk of zinc deficiency.

Ion channels are well placed to transduce environmental cues into signals used by cells to generate a wide range of responses, but little is known about their role in the regulation of RNA metabolism. Here we show that the TRPV4 cation channel binds the DEAD-box RNA helicase DDX3X and regulates its function. TRPV4-mediated Ca2+ influx releases DDX3X from the channel and drives DDX3X nuclear translocation, a process that involves calmodulin (CaM) and the CaM-dependent kinase II. Genetic depletion or pharmacological inhibition of TRPV4 diminishes DDX3X-dependent functions, including nuclear viral export and translation. Furthermore, TRPV4 mediates Ca2+ influx and nuclear accumulation of DDX3X in cells exposed to the Zika virus or the purified viral envelope protein. Consequently, targeting of TRPV4 reduces infectivity of dengue, hepatitis C and Zika viruses. Together, our results highlight the role of TRPV4 in the regulation of DDX3X-dependent control of RNA metabolism and viral infectivity.

bProcessing bodies (P-bodies) are highly dynamic cytoplasmic granules conserved among eukaryotes. They are present under normal growth conditions and contain translationally repressed mRNAs together with proteins from the mRNA decay and microRNA (miRNA) machineries. We have previously shown that the core P-body components PatL1, LSm1, and DDX6 (Rck/p54) are required for hepatitis C virus (HCV) RNA replication; however, how HCV infection affects P-body granules and whether P-body granules per se influence the HCV life cycle remain unresolved issues. Here we show that HCV infection alters P-body composition by specifically changing the localization pattern of P-body components that are required for HCV replication. This effect was not related to an altered expression level of these components and could be reversed by inhibiting HCV replication with a polymerase inhibitor. Similar observations were obtained with a subgenomic replicon that supports only HCV translation and replication, indicating that these early steps of the HCV life cycle trigger the P-body alterations. Finally, P-body disruption by Rap55 depletion did not affect viral titers or HCV protein levels, demonstrating that the localization of PatL1, LSm1, and DDX6 in P-bodies is not required for their function on HCV. Thus, the HCV-induced changes on P-bodies are mechanistically linked to the function of specific P-body components in HCV RNA translation and replication; however, the formation of P-body granules is not required for HCV infection. Hepatitis C virus (HCV), a positive-strand RNA virus of the Flaviviridae family, is a major human pathogen. It has chronically infected around 170 million individuals worldwide and is a major cause of chronic liver disease and liver transplantation (24). Impressive advances in understanding the HCV life cycle have been achieved over the last years. These include the identification of cellular factors necessary for HCV entry into target cells, the elucidation of the viral multiplication requirements, and the description of cellular compartments necessary for particle assembly and progeny virus production (7). These advances not only increase our understanding of fundamental steps in HCV biology but also highlight the intimate relationship of virus components with cellular host factors.Components of the so-called processing bodies (P-bodies) are among the host factors required for efficient HCV multiplication (5,20,26,37,38). P-bodies are discrete and highly dynamic granules present in the cytoplasm of eukaryotic cells under normal growth conditions (18, 23). They contain translationally repressed mRNAs together with multiple proteins from the mRNA decay pathway and the microRNA (miRNA) machinery. Once in P-bodies, mRNAs can be either degraded or stored for a later return into translation (9,12,15). Experiments involving fluorescence recovery after photobleaching (FRAP) revealed that P-body components rapidly cycle in and out of these granules, indicating that there is a constant exchange of molecules with the cyt...

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Hepatitis C virus (HCV) infection is the leading cause of chronic liver diseases. Water extracts of the leaves of the wild Egyptian artichoke (WEA) [Cynara cardunculus L. var. sylvestris (Lam.) Fiori] have been used for centuries in the Sinai Peninsula to treat hepatitis symptoms. Here we isolated and characterized six compounds from the water extracts of WEA and evaluated their HCV inhibition capacities in vitro. Importantly, two of these compounds, grosheimol and cynaropicrin, inhibited HCV with half-maximal effective concentrations (EC 50 s) in the low micromolar range. They inhibited HCV entry into target cells and were active against both cell-free infection as well as cell-cell transmission. Furthermore, the antiviral activity of both compounds was pan-genotypic as HCV genotypes 1a, 1b, 2b, 3a, 4a, 5a, 6a, and 7a were inhibited. Thus, grosheimol and cynaropicrin are promising candidates for the development of new pan-genotypic entry inhibitors of HCV infection. IMPORTANCEBecause there is no preventive HCV vaccine available today, the discovery of novel anti-HCV cell entry inhibitors could help develop preventive measures against infection. The present study describes two compounds isolated from the wild Egyptian artichoke (WEA) with respect to their structural elucidation, absolute configuration, and quantitative determination. Importantly, both compounds inhibited HCV infection in vitro. The first compound was an unknown molecule, and it was designated "grosheimol," while the second compound is the known molecule cynaropicrin. Both compounds belong to the group of sesquiterpene lactones. The mode of action of these compounds occurred during the early steps of the HCV life cycle, including cell-free and cell-cell infection inhibition. These natural compounds present promising candidates for further development into anti-HCV therapeutics. Hepatitis C virus (HCV) is an enveloped, positive-strand RNA virus classified as a separate genus (Hepacivirus) within the Flaviviridae family. It shows a high degree of genetic diversity, with 7 major circulating genotypes (1). HCV is mainly transmitted through exposure to HCV-contaminated blood. Most infections remain persistent, summing up to an estimated 150 million chronic HCV carriers worldwide (2). As persistent HCV infection frequently causes chronic hepatitis that can progress to liver cirrhosis and liver cell carcinoma, it is a major threat to human health (3, 4).Treatment options for chronically infected individuals have dramatically improved over the last few years. This has been due to the development of highly potent direct-acting antivirals (DAAs) that increased sustained response rates to over 90%, even in interferon-free combinations (5). Currently approved DAAs include NS3/4A protease inhibitors (telaprevir, boceprevir, and simeprevir), NS5A inhibitors (daclatasvir and ledipasvir), and the NS5B polymerase inhibitor sofosbuvir. Further antiviral drugs are in clinical trials and are about to be approved. Nonetheless, the rapid replication of HCV, al...