Identification of neuraminidase inhibitors against dual H274Y/I222R mutant strains

Abstract

Influenza is an annual seasonal epidemic that has continually drawn public attentions, due to the potential death toll and drug resistance. Neuraminidase, which is essential for the spread of influenza virus, has been regarded as a valid target for the treatment of influenza infection. Although neuraminidase drugs have been developed, they are susceptible to drug-resistant mutations in the sialic-binding site. In this study, we established computational models (site-moiety maps) of H1N1 and H5N1 to determine properties of the 150-cavity, which is adjacent to the drug-binding site. The models reveal that hydrogen-bonding interactions with residues R118, D151, and R156 and van der Waals interactions with residues Q136, D151, and T439 are important for identifying 150-cavitiy inhibitors. Based on the models, we discovered three new inhibitors with IC50 values <10 μM that occupies both the 150-cavity and sialic sites. The experimental results identified inhibitors with similar activities against both wild-type and dual H274Y/I222R mutant neuraminidases and showed little cytotoxic effects. Furthermore, we identified three new inhibitors situated at the sialic-binding site with inhibitory effects for normal neuraminidase, but lowered effects for mutant strains. The results suggest that the new inhibitors can be used as a starting point to combat drug-resistant strains.

Optimization of N-Substituted Oseltamivir Derivatives as Potent Inhibitors of Group-1 and -2 Influenza A Neuraminidases, Including a Drug-Resistant Variant

“…Based on the above information and our previously established structure-activity relationships (SAR) results,34,43 we concluded that N,N-dialkyl-substituted aniline derivatives preferentially bind to the 150-cavity of both group-1 and -2 NAs, and thekey factors influencing the activities are the size, flexibility and hydrophobicity of the N,N-dialkyl substituted group. Compounds with N,N-diethylamino (15b) and 1-pyrrolidinyl groups (15c), which possess moderate size, flexibility, and hydrophobicity, at the R-position enhanced the activities against both group-1 and -2 wild-type NAs, while relatively bulky, rigid (15d and 19) or small (15a) substituent groups appeared to have a negative effect on the potency, possibly because their conformational effects impaired the binding of other structural parts of oseltamivir derivatives to the corresponding pockets of the active site.…”

“…Consequently, an aromatic ring with polar moieties may be sterically and electronically complementary to the 150-cavity. 43 In addition, MD studies indicated that the triazole-containing oseltamivir analogs (11 and 12, 39 which were designed to adapt to the 150-cavity of N1 and N2, and showed higher efficacy against H3N2 strain than H1N1 strain) could alternatively occupy the 150-cavity and the catalytic site of N1 or N2, because of the short triazole group and the rigid and large angle between the central ring and the triazole group. Even so, it was clear that the 150-cavity of group-2 could be induced to open by oseltamivir derivatives, and N-containing groups (triazole group) play an important role in this process.…”

Inhibition of sialidase activity as a therapeutic approach

“…This approach and identification of novel inhibitors have been described recently. 8 The design of novel inhibitors implemented a virtual screening of the National Cancer Institute (NCI) database compounds followed by establishing a site-moiety map for studying the binding site of dual H274Y/I222R mutant neuraminidase. Overall study framework consisted of virtual screening for inhibitors, modeling consensus interactions between docked compounds and amino acids of the enzyme, building site-moiety map to identify potential binding pockets, and listing the potential inhibitors.…”

“…The authors concluded that exploiting the 150-cavity to form an open conformation of the enzyme is beneficial for neuraminidase inhibition. 8 …”

Sialic acid and biology of life: An introduction

“…But design of carbohydrate-derived drug molecules faces challenges such as pharmacokinetic profiles, poor bioavailability, requirement for active transport through membranes, short plasma half-life, poor metabolic stability, and are rapidly excreted [379,380]. However, this area of biology is developing with studies or approaches to improve their pharmacokinetic profiles like systematic structural modifications such as the replacement of certain moieties, the introduction of hydrophobic moieties, and/or the incorporation of a prodrug strategy leading to compounds that mimic the biological activity of their carbohydrate precursors called as 'glycomimetics' like neuraminidase inhibitors zanamivir and oseltamivir [381,382].…”