Hepatitis C virus (HCV) chronically infects 170 million individuals, causing severe liver disease. Although antiviral chemotherapy exists, the current regimen is ineffective in 50% of cases due to high levels of innate virus resistance. New, virus-specific therapies are forthcoming although their development has been slow and they are few in number, driving the search for new drug targets. The HCV p7 protein forms an ion channel in vitro and is critical for the secretion of infectious virus. p7 displays sensitivity to several classes of compounds, making it an attractive drug target. We recently demonstrated that p7 compound sensitivity varies according to viral genotype, yet little is known of the residues within p7 responsible for channel activity or drug interactions. Here, we have employed a liposome-based assay for p7 channel function to investigate the genetic basis for compound sensitivity. We demonstrate using chimeric p7 proteins that neither the two transmembrane helices nor the p7 basic loop individually determines compound sensitivity. Using point mutation analysis, we identify amino acids important for channel function and demonstrate that null mutants exert a dominant negative effect over wild-type protein. We show that, of the three hydrophilic regions within the amino-terminal trans-membrane helix, only the conserved histidine at position 17 is important for genotype 1b p7 channel activity. Mutations predicted to play a structural role affect both channel function and oligomerization kinetics. Lastly, we identify a region at the p7 carboxy terminus which may act as a specific sensitivity determinant for the drug amantadine.Hepatitis C virus (HCV) chronically infects 170 million individuals and is a major cause of severe liver disease such as cirrhosis and hepatocellular carcinoma. Acute HCV infection is asymptomatic which, combined with the lack of an available vaccine, means that the majority of carriers are unaware of their positive status. Thus, clinical intervention takes place upon the presentation of symptoms when liver damage is already extensive and when the virus is well established. Current therapy comprises a combination of pegylated alpha interferon (IFN-␣) with ribavirin (Rib), which is effective in only 50% of cases and is both expensive and poorly tolerated by patients. This relatively low success rate is due to the highly prevalent, IFN-resistant genotype 1 viruses; other genotypes generally respond well to treatment (27). As IFN-Rib acts primarily via stimulation of the immune system, improving current therapy relies on the development of new, virus-specific drugs. A small number of polymerase and protease inhibitors are at late stages of development, but progress has been hampered by the inability until recently to culture HCV in vitro (21, 40, 45). The highly variable nature of HCV, however, means that new drugs will most likely have to be used in combination, making expansion of available drug targets and the development of new inhibitors a major research focus.HCV is the prot...

The hepatitis C virus (HCV) p7 ion channel plays a critical role during infectious virus production and represents an important new therapeutic target. Its activity is blocked by structurally distinct classes of small molecules, with sensitivity varying between isolate p7 sequences. Although this is indicative of specific protein-drug interactions, a lack of highresolution structural information has precluded the identification of inhibitor binding sites, and their modes of action remain undefined. Furthermore, a lack of clinical efficacy for existing p7 inhibitors has cast doubt over their specific antiviral effects. We identified specific resistance mutations that define the mode of action for two classes of p7 inhibitor: adamantanes and alkylated imino sugars (IS). Adamantane resistance was mediated by an L20F mutation, which has been documented in clinical trials. Molecular modeling revealed that L20 resided within a membrane-exposed binding pocket, where drug binding prevented low pH-mediated channel opening. The peripheral binding pocket was further validated by a panel of adamantane derivatives as well as a bespoke molecule designed to bind the region with high affinity. By contrast, an F25A polymorphism found in genotype 3a HCV conferred IS resistance and confirmed that these compounds intercalate between p7 protomers, preventing channel oligomerization. Neither resistance mutation significantly reduced viral fitness in culture, consistent with a low genetic barrier to resistance occurring in vivo. Furthermore, no cross-resistance was observed for the mutant phenotypes, and the two inhibitor classes showed additive effects against wild-type HCV. Conclusion: These observations support the notion that p7 inhibitor combinations could be a useful addition to future HCV-specific therapies. (HEPATOLOGY 2011;54:79-90) H epatitis C virus (HCV) infects over 3% of the population, causing severe liver disease. Current therapy comprising pegylated interferon (IFN) and ribavirin (Rib) is inadequate, which, combined with high cost and poor patient compliance, has driven the demand for new virus-specific drugs.1 Future standard of care will replace IFN/Rib with combinations of specific inhibitors, such as seen for human immunodeficiency virus (HIV) therapy. However, extensive HCV variability raises concerns over the ability of relatively few compounds to suppress resistance. Thus, great effort focuses on expanding the repertoire of HCV drug targets, expedited by the availability of the Japanese fulminant hepatitis clone 1 (JFH-1) infectious isolate.

Human respiratory syncytial virus (HRSV) is the leading cause of lower respiratory tract disease in infants. The HRSV small hydrophobic (SH) protein plays an important role in HRSV pathogenesis, although its mode of action is unclear. Analysis of the ability of SH protein to induce membrane permeability and form homo-oligomers suggests it acts as a viroporin. For the first time, we directly observed functional SH protein using electron microscopy, which revealed SH forms multimeric ring-like objects with a prominent central stained region. Based on current and existing functional data, we propose this region represents the channel that mediates membrane permeability.Structured summaryMINT-7890792, MINT-7890805: SH (uniprotkb:P04852) and SH (uniprotkb:P04852) bind (MI:0407) by chromatography technology (MI:0091)MINT-7890784, MINT-7890776: SH (uniprotkb:P04852) and SH (uniprotkb:P04852) bind (MI:0407) by electron microscopy (MI:0040)

The product of the human cytomegalovirus (HCMV) gene UL144, expressed at early times postinfection, is located in the UL/b region of the viral genome and is related to members of the tumor necrosis factor receptor superfamily, but it does not bind tumor necrosis factor superfamily ligands. However, UL144 does activate NF-B, resulting in NF-B-mediated activation of the cellular chemokine CCL22. Consistent with this finding, isolates of HCMV lacking the UL/b region show no such activation of CCL22. Recently, it has been suggested that activation of NF-B is repressed by the product of the viral gene IE86: IE86 appears to block NF-B binding to DNA but not nuclear translocation of NF-B. Intriguingly, IE86 is detectable throughout an infection with the virus, so how UL144 is able to activate NF-B in the presence of continued IE86 expression is unclear. Here we show that although IE86 does repress the UL144-mediated activation of a synthetic NF-B promoter, it is unable to block UL144-mediated activation of the CCL22 promoter, and this lack of responsiveness to IE86 appears to be regulated by binding of the CREB transcription factor.

ABSTRACr A study of the health of 78 workers in an iron and steel foundry in Vancouver, British Columbia, was carried out and the results compared with those found in 372 railway repair yard workers who were not significantly exposed to air contaminants at work. The foundry workers were exposed to PepSet, which consists of diphenyl methane diisocyanate (MDI) and phenol formaldehyde and their decomposition products as well as to silica containing particulates. A questionnaire was administered by trained interviewers, and chest radiography, allergy skin tests, pulmonary function tests, and methacholine inhalation tests were carried out as well as measurement levels of dust and MDI. Compared with the controls, the foundry workers had more respiratory symptoms and a significantly lower mean FEV, and FEF2,-,,% after adjustments had been made for differences in age, height, and smoking habit. Three workers (4.8%) had radiographic evidence of pneumoconiosis and 12 (18-2%) had asthma defined as presence of bronchial hyperreactivity, cough, and additional respiratory symptoms such as wheeze, chest tightness, or breathlessness. Sensitisation to MDI is probably the cause of asthma in these workers.After several workers in a foundry in Vancouver had been admitted to hospital with acute dyspnoea in the previous six months, the labour union requested the occupational diseases research unit of the University of British Columbia to conduct a health study in 1981. The foundry housed all operations within one building including metal melting, mould and core making, pouring of molten metal into moulds, shaking out casts from moulds, and grinding of irregularities from casts. The workers were exposed to several air contaminants including sand containing silica, metal dust, and chemicals used as binders for mould and core making, as well as a variety of gaseous emissions derived from the thermal decomposition of the chemical binders. The latter included carbon monoxide, carbon dioxide, hydrocarbons, carbonyl sulphide, hydrogen sul-

The recent increase in new technologies to analyze host-pathogen interaction has fostered a race to develop new methodologies to assess these not only on the cellular level, but also on the tissue level. Due to mouse-other mammal differences, there is a desperate need to develop relevant tissue models that can more closely recapitulate the host tissue during disease and repair. Whereas organoids and organs-on-a-chip technologies have their benefits, they still cannot provide the cellular and structural complexity of the host tissue. Here, precision cut tissue slices (PCTS) may provide invaluable models for complex ex-vivo generated tissues to assess host-pathogen interaction as well as potential vaccine responses in a “whole organ” manner. In this mini review, we discuss the current literature regarding PCTS in veterinary species and advocate that PCTS represent remarkable tools to further close the gap between target identification, subsequent translation of results into clinical studies, and thus opening avenues for future precision medicine approaches.

Pandemic influenza A virus (IAV) remains a significant threat to global health. Preparedness relies primarily upon a single class of neuraminidase (NA) targeted antivirals, against which resistance is steadily growing. The M2 proton channel is an alternative clinically proven antiviral target, yet a near-ubiquitous S31N polymorphism in M2 evokes resistance to licensed adamantane drugs. Hence, inhibitors capable of targeting N31 containing M2 (M2-N31) are highly desirable. Rational in silico design and in vitro screens delineated compounds favouring either lumenal or peripheral M2 binding, yielding effective M2-N31 inhibitors in both cases. Hits included adamantanes as well as novel compounds, with some showing low

Secreted infectious particles generated by the genotype 2a JFH-1 hepatitis C virus infectious clone are resistant to acidic pH, whereas intracellular virions remain acid-labile. Thus, JFH-1 particles are thought to undergo pH maturation as they are secreted from the cell. Here, we demonstrate that both infectious intracellular and secreted genotype 1a (H77)/JFH-1 chimaeric particles display enhanced acid sensitivity compared with JFH-1, although pH maturation still occurs upon release. Introduction of p7 sequences from genotype 1a infected HCV patients into the H77/JFH-1 background yielded variable effects on infectious particle production and sensitivity to small molecule inhibitors. However, two selected patient p7 sequences increased the acid stability of secreted, but not intracellular H77/JFH-1 particles, suggesting that p7 directly influences particle pH maturation via an as yet undefined mechanism. We propose that HCV particles vary in acid stability, and that this may be dictated by variations in both canonical structural proteins and p7.