Therapeutic efficacy of a respiratory syncytial virus fusion inhibitor (original) (raw)
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nature CHeMICaL BIOLOGY | AdvAnce online publicAtion | www.nature.com/naturechemicalbiology 4 Respiratory infections Research, Janssen infectious diseases & vaccines bvbA, beerse, belgium. 5 discovery Sciences, Janssen pharmaceutica nv, beerse, belgium. 6 Medicinal chemistry department, Janssen infectious diseases & vaccines bvbA, beerse, belgium. 7 computational chemistry, Janssen R&d llc, Spring House, pennsylvania, uSA. 8 department of pediatrics, the ohio State university college of MedicineRespiratory syncytial virus (RSV) is a leading cause of pneumonia and bronchiolitis in young children and the elderly. Therapeutic small molecules have been developed that bind the RSV F glycoprotein and inhibit membrane fusion, yet their binding sites and molecular mechanisms of action remain largely unknown. Here we show that these inhibitors bind to a three-fold-symmetric pocket within the central cavity of the metastable prefusion conformation of RSV F. Inhibitor binding stabilizes this conformation by tethering two regions that must undergo a structural rearrangement to facilitate membrane fusion. Inhibitor-escape mutations occur in residues that directly contact the inhibitors or are involved in the conformational rearrangements required to accommodate inhibitor binding.
Molecular mechanism of respiratory syncytial virus fusion inhibitors
Nature Chemical Biology, 2015
Respiratory syncytial virus (RSV) is a leading cause of pneumonia and bronchiolitis in young children and the elderly. Therapeutic small molecules have been developed that bind the RSV F glycoprotein and inhibit membrane fusion, yet their binding sites and molecular mechanisms of action remain largely unknown. Here we show that these inhibitors bind to a threefold symmetric pocket within the central cavity of the metastable prefusion conformation of RSV F. Inhibitor binding stabilizes this conformation by tethering two regions that must undergo a structural rearrangement to facilitate membrane fusion. Inhibitor-escape mutations occur in residues that directly contact the inhibitors or are involved in the conformational rearrangements required to accommodate inhibitor binding. Resistant viruses do not propagate as well as wild-type RSV in vitro, indicating a fitness cost for inhibitor escape. Collectively, these findings provide new insight into class I viral fusion proteins and should facilitate development of optimal RSV fusion inhibitors.
Journal of Antimicrobial Chemotherapy, 2005
BMS-433771 is an orally bioavailable respiratory syncytial virus (RSV) inhibitor, functioning through inhibition of viral F protein-induced membrane fusion. The compound is active against both A and B groups of RSV, with an average EC 50 of 20 nM. BMS-433771 is also efficacious against RSV infection in two rodent models when dosed orally prior to infection. The compound possesses good pharmacokinetic properties, while maintaining a favourable toxicity profile. Consequently, BMS-433771 is well suited for further clinical evaluation in humans. Direct affinity labelling studies indicate that the compound binds in a hydrophobic cavity within the trimeric N-terminal heptad repeat. During the fusion process, this heptad repeat associates with a C-terminal heptad repeat to form a six helical coiled-coil bundle (or trimer-of-hairpins), and BMS-433771 presumably interferes with the functional association of these heptad repeats. The fusion protein of many other class 1 fusion viruses, such as HIV and influenza, form similar hairpin structures as a prelude to membrane fusion. The identification of BMS-433771 provides a proof of concept for small molecule inhibitors that target the formation of the six helical coiled-coil structure, which could be a prototype for the development of similar antivirals against other class 1 fusion viruses.
Antimicrobial Agents and Chemotherapy, 2005
Here we present data on the mechanism of action of VP-14637 and JNJ-2408068 (formerly R-170591), two small-molecule inhibitors of respiratory syncytial virus (RSV). Both inhibitors exhibited potent antiviral activity with 50% effective concentrations (EC 50 s) of 1.4 and 2.1 nM, respectively. A similar inhibitory effect was observed in a RSV-mediated cell fusion assay (EC 50 ؍ 5.4 and 0.9 nM, respectively). Several drug-resistant RSV variants were selected in vitro in the presence of each compound. All selected viruses exhibited significant cross-resistance to both inhibitors and contained various single amino acid substitutions in two distinct regions of the viral F protein, the heptad repeat 2 (HR2; mutations D486N, E487D, and F488Y), and the intervening domain between HR1 and HR2 (mutation K399I and T400A).
Design and characterization of human respiratory syncytial virus entry inhibitors
Antiviral …, 2005
Human respiratory syncytial virus (hRSV) is a pathogen of worldwide health concern. The crucial membrane fusion event during viral entry into host cells involves a 'trimerof-hairpins' structure that brings the amino (N)-and carboxy (C)-terminal regions of the viral fusion glycoprotein (F protein) into close proximity. Two heptad repeat regions that are highly conserved in the F protein -HR1 (N-terminal) and HR2 (C-terminal) -have an important role in this process. It has been shown that both HR1and HR2-based peptides can inhibit viral entry. However, these proteins, and the HR1 peptides in particular, are liable to aggregation. We designed three peptides containing multiple copies of alternating HR1 and HR2 sequences denoted 5-Helix, HR121 and HR212, respectively. The 5-Helix, HR121 and HR212 proteins were functionally analogous to single HR1, HR1 and HR2 sequences, respectively. All three proteins were expressed in soluble form and biophysical analysis showed that they exhibited α-helical secondary structures. The three proteins were potent fusion inhibitors in vitro, at the micromolar scale, with the HR1 analogues being approximately two times more effective than the HR2 analogue. Our results suggest that these rationally designed protein inhibitors could serve as a new class of anti-hRSV agents.
Orally Active Fusion Inhibitor of Respiratory Syncytial Virus
Antimicrobial Agents and Chemotherapy, 2004
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Nature communications, 2017
Human respiratory syncytial virus (RSV) is the main cause of lower respiratory tract infections in young children. The RSV fusion protein (F) is highly conserved and is the only viral membrane protein that is essential for infection. The prefusion conformation of RSV F is considered the most relevant target for antiviral strategies because it is the fusion-competent form of the protein and the primary target of neutralizing activity present in human serum. Here, we describe two llama-derived single-domain antibodies (VHHs) that have potent RSV-neutralizing activity and bind selectively to prefusion RSV F with picomolar affinity. Crystal structures of these VHHs in complex with prefusion F show that they recognize a conserved cavity formed by two F protomers. In addition, the VHHs prevent RSV replication and lung infiltration of inflammatory monocytes and T cells in RSV-challenged mice. These prefusion F-specific VHHs represent promising antiviral agents against RSV.
Journal of virology, 2017
The human respiratory syncytial virus (hRSV) fusion (F) protein is considered a major target of the neutralizing antibody response to hRSV. This glycoprotein undergoes a major structural shift from the prefusion (pre-F) to the postfusion (post-F) state at the time of virus-host cell membrane fusion. Recent evidences suggest that the pre-F state is a superior target for neutralizing antibodies compared to the post-F state. Therefore, for vaccine purposes, we have designed and characterized a recombinant hRSV F protein, called Pre-F-GCN4t, stabilized in a pre-F conformation. To show that Pre-F-GCN4t does not switch to a post-F conformation, it was compared with a recombinant post-F molecule, called Post-F-XC. Pre-F-GCN4t was glycosylated and trimeric and displayed a conformational stability different from that of Post-F-XC, as shown by chemical denaturation. Electron microscopy analysis suggested that Pre-F-GCN4t adopts a lollipop-like structure. In contrast, Post-F-XC had a typical e...
Evaluation of Small Molecule Combinations against Respiratory Syncytial Virus In Vitro
Molecules, 2021
Respiratory syncytial virus (RSV) is a major pathogen that causes severe lower respiratory tract infection in infants, the elderly and the immunocompromised worldwide. At present no approved specific drugs or vaccines are available to treat this pathogen. Recently, several promising candidates targeting RSV entry and multiplication steps are under investigation. However, it is possible to lead to drug resistance under the long-term treatment. Therapeutic combinations constitute an alternative to prevent resistance and reduce antiviral doses. Therefore, we tested in vitro two-drug combinations of fusion inhibitors (GS5806, Ziresovir and BMS433771) and RNA-dependent RNA polymerase complex (RdRp) inhibitors (ALS8176, RSV604, and Cyclopamine). The statistical program MacSynergy II was employed to determine synergism, additivity or antagonism between drugs. From the result, we found that combinations of ALS8176 and Ziresovir or GS5806 exhibit additive effects against RSV in vitro, with i...