Influenza therapeutics with new targets and mechanisms of action are urgently needed to combat potential new pandemics, emerging viruses, and constantly mutating circulating strains. We report here on design and structural characterization of potent peptidic inhibitors against influenza hemagglutinin (HA). The peptide design was based on complementarity determining region (CDR) loops of anti-HA human broadly neutralizing antibodies, FI6v3 and CR9114. The optimized peptides exhibit nanomolar affinity and neutralization against group 1 influenza A viruses including the 2009 H1N1 pandemic and avian H5N1 strains. The peptide inhibitors bind to the highly conserved stem epitope and block the low pH-induced conformational rearrangements associated with membrane fusion. These peptidic compounds and their advantageous biological properties should accelerate development of novel small molecule and peptide-based therapeutics against influenza virus.

We have discovered a novel class of human immunodeficiency virus (HIV) reverse transcriptase (RT) inhibitors that block the polymerization reaction in a mode distinct from those of the nucleoside or nucleotide RT inhibitors (NRTIs) and nonnucleoside RT inhibitors (NNRTIs). For this class of indolopyridone compounds, steady-state kinetics revealed competitive inhibition with respect to the nucleotide substrate. Despite substantial structural differences with classical chain terminators or natural nucleotides, these data suggest that the nucleotide binding site of HIV RT may accommodate this novel class of RT inhibitors. To test this hypothesis, we have studied the mechanism of action of the prototype compound indolopyridone-1 (INDOPY-1) using a variety of complementary biochemical tools. Time course experiments with heteropolymeric templates showed "hot spots" for inhibition following the incorporation of pyrimidines (T>C). Moreover, binding studies and site-specific footprinting experiments revealed that INDOPY-1 traps the complex in the posttranslocational state, preventing binding and incorporation of the next complementary nucleotide. The novel mode of action translates into a unique resistance profile. While INDOPY-1 susceptibility is unaffected by mutations associated with NNRTI or multidrug NRTI resistance, mutations M184V and Y115F are associated with decreased susceptibility, and mutation K65R confers hypersusceptibility to INDOPY-1. This resistance profile provides additional evidence for active site binding. In conclusion, this class of indolopyridones can occupy the nucleotide binding site of HIV RT by forming a stable ternary complex whose stability is mainly dependent on the nature of the primer 3 end.The reverse transcriptase (RT) enzyme of human immunodeficiency virus type 1 (HIV-1) remains a major target in antiretroviral therapy, with the current standard of care being the use of two nucleoside or nucleotide analogue reverse transcriptase inhibitors (NRTIs), combined with one nonnucleoside reverse transcriptase inhibitor (NNRTI) or protease inhibitor (32).Upon entry into the cell, the virus is uncoated, and the viral RT enzyme converts its single-stranded RNA genome into double-stranded proviral DNA. Inhibition of this crucial event in the early viral life cycle ultimately precludes the virus from proliferating. Following the intracellular phosphorylation of NRTIs, NRTI-triphosphates compete with natural deoxyribonucleoside triphosphate (dNTP) pools and bind to the RT active site. They act as chain terminators due to the lack of a 3Ј-hydroxyl group (31). In contrast, NNRTIs represent a chemically diverse class of compounds that bind to a pocket in the vicinity of the catalytic site (25,29,30). Binding of these inhibitors is noncompetitive with respect to both dNTPs and template/primer (16).Despite the potency of combinations of NRTIs and NNRTIs, the emergence of mutations conferring resistance remains a major cause for treatment failure. The advent of novel RT inhibitors with a different mechani...

Dengue virus (DENV) causes ~96 million symptomatic infections annually, manifesting as dengue fever or occasionally as severe dengue 1,2 . There are no antivirals available to prevent or treat dengue. We describe a highly potent DENV inhibitor (JNJ-A07) that exerts nano-to picomolar activity against a panel of 21 clinical isolates, representing the natural genetic diversity of known geno-and serotypes. The molecule has a high barrier to resistance and prevents the formation of the viral replication complex by blocking the interaction between two viral proteins (NS3 and NS4B), thus unveiling an entirely novel mechanism of antiviral action. JNJ-A07 has an excellent pharmacokinetic profile that results in outstanding efficacy against DENV infection in mouse infection models. Delaying start of treatment until peak viremia results in a rapid and significant reduction in viral load. An analogue is currently in further development. MAIN TEXTDengue is currently considered one of the top10 global health threats 1 . Annually, an estimated 96 million develop dengue disease 2 , which is likely an underestimation [3][4][5] . The incidence has increased ~30-fold over the past 50 years. The virus is endemic in 128 countries in (sub-)tropical regions, with an estimated 3.9 billion people at risk of infection. A recent study predicts an increase to 6.1 billion people at risk by 2080 6 . The upsurge is driven by factors such as rapid urbanization and the sustained spread of the mosquito vectors [6][7][8] . DENV has four serotypes (further classified into genotypes), which are increasingly co-circulating in endemic regions. A second infection with a different serotype increases the risk of severe dengue 9,10 . The vaccine Dengvaxia ® , which is approved in a number of countries for those aged ≥9 years, is only recommended for those with previous dengue exposure 11,12,13 . There are no antivirals for the prevention or treatment of dengue; the development of pan-serotype DENV inhibitors has proven challenging 14,15 .

Graft rejection in transplant patients is managed clinically by suppressing T-cell function with immunosuppressive drugs such as prednisolone and methylprednisolone. In such immunocompromised hosts, human cytomegalovirus (HCMV) is an important opportunistic pathogen and can cause severe morbidity and mortality. Currently, the effect of glucocorticosteroids (GCSs) on the HCMV life cycle remains unclear. Previous reports showed enhanced lytic replication of HCMV in vitro in the presence of GCSs. In the present study, we explored the implications of steroid exposure on latency and reactivation. We observed a direct effect of several GCSs used in the clinic on the activation of a quiescent viral major immediate-early promoter in stably transfected THP-1 monocytic cells. This activation was prevented by the glucocorticoid receptor (GR) antagonist Ru486 and by shRNA-mediated knockdown of the GR. Consistent with this observation, prednisolone treatment of latently infected primary monocytes resulted in HCMV reactivation. Analysis of the phenotype of these cells showed that treatment with GCSs was correlated with differentiation to an anti-inflammatory macrophage-like cell type. On the basis that these observations may be pertinent to HCMV reactivation in post-transplant settings, we retrospectively evaluated the incidence, viral kinetics and viral load of HCMV in liver transplant patients in the presence or absence of GCS treatment. We observed that combination therapy of baseline prednisolone and augmented methylprednisolone, upon organ rejection, significantly increased the incidence of HCMV infection in the intermediate risk group where donor and recipient are both HCMV seropositive (D+R+) to levels comparable with the high risk D+R− group.

The synthesis of 1-alkyl- and 1-aryl-1H-naphtho[2,3-c]pyran-5,10-diones, bearing a C(3)−C(4) double bond, was performed by two alternative cyclization strategies of 2,3-disubstituted 1,4-naphthoquinones. Lemieux−Johnson oxidation of 2-allyl-3-hydroxymethyl-1,4-dimethoxynaphthalenes and subsequent oxidative demethylation of the intermediate 3,4-dihydro-5,10-dimethoxy-1H-naphtho[2,3-c]pyran-3-oles to the corresponding 3,4-dihydro-3-hydroxy-1H-naphtho[2,3-c]pyran-5,10-diones gave, after acid-catalyzed dehydration, the desired 1H-naphtho[2,3-c]pyran-5,10-diones. Alternatively, the pyranonaphthoquinone ring system was constructed by intramolecular acid-catalyzed condensation of (3-hydroxymethyl-1,4-naphthoquinone-2-yl)acetaldehyde acetals. Using this synthetic approach, the synthesis of two naturally occurring naphthoquinone antibiotics, pentalongin and psychorubrin, is reported.