Identification of pyrrolo[3,2-c]pyridin-4-amine compounds as a new class of entry inhibitors against influenza viruses in vitro

• Published in: Biochemical and biophysical research communications 2016-09, Vol.478 (4), p.1594-1601
• Main Authors: Chang, So Young, Cruz, Deu John M., Ko, Yoonae, Min, Ji-Young
• Format: Article
• Language: English
• Subjects: 60 APPLIED LIFE SCIENCES; A549 Cells; AMINES; Animals; Antiviral Agents - pharmacology; Antiviral drugs; Birds - virology; Cell Death - drug effects; Dogs; DRUGS; Entry inhibitor; HIGH-TC SUPERCONDUCTORS; High-throughput screening; Humans; Influenza A virus; Influenza A virus - drug effects; Influenza B virus; Influenza B virus - drug effects; Influenza in Birds - virology; Influenza virus; INFLUENZA VIRUSES; INHIBITION; Madin Darby Canine Kidney Cells; Nuclear Proteins - metabolism; Orthomyxoviridae; Orthomyxoviridae - drug effects; Pyridines - chemistry; Pyridines - pharmacology; PYRROLES; Pyrroles - chemistry; Pyrroles - pharmacology; Pyrrolopyridinamine; Small Molecule Libraries - chemistry; Small Molecule Libraries - pharmacology; Virus Internalization - drug effects
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2016.08.162

Various influenza virus entry inhibitors are being developed as therapeutic antiviral agents in ongoing preparation for emerging influenza viruses, particularly those that may possess drug resistance to the current FDA-approved neuraminidase inhibitors. In this study, small molecules having the pyrrolopyridinamine (PPA), aminothiadiazole (ATD), dihydrofuropyridine carboxamide (HPC), or imidazopyridinamine (IPA) moiety were selected from a target-focused chemical library for their inhibitory activity against influenza A virus by high-throughput screening using the PR8GFP assay. Activity was evaluated by measuring changes the proportion of GFP-expressing cells as a reflection of influenza virus infection. Among them, PPA showed broad-spectrum activity against multiple influenza A viruses and influenza B virus. PPA was found to block the early stages of influenza virus infection using a time-of-addition assay. Using additional phenotypic assays that dissect the virus entry process, it appears that the antiviral activity of PPA against influenza virus can be attributed to interference of the post-fusion process: namely, virus uncoating and nuclear import of viral nucleoprotein complexes. Based on these results, PPA is an attractive chemical moiety that can be used to develop new antiviral drug candidates against influenza viruses. •Four chemical classes are identified from target-focused chemical library by HTS.•PPA inhibits the infection of various influenza A viruses and influenza B virus.•PPA is identified to inhibit the early stages of influenza virus infection.•PPA compound disrupts virus uncoating and nuclear import of viral ribonucleoprotein.