title: Amino acid derivatives of the (-) enantiomer of gossypol are effective fusion inhibitors of human immunodeficiency virus type 1.
abstract: T20 and maraviroc are the only two currently available entry inhibitors that have shown efficacy in treating HIV-1-infected individuals who have failed to respond to first-line antiretroviral drugs. Gossypol is a polyphenolic aldehyde extracted from cotton plants. By modifying the (-) enantiomer of gossypol with a series of small molecules, we have found that neutral amino acids with aliphatic group derivatives of (-) gossypol show the strongest inhibitory activity and the lowest cytotoxicity in vitro among all the derivatives tested. Additionally, the selectivity index of the (-) gossypol-neutral amino acid conjugates is increased 100-fold when compared with (-) gossypol alone. It is widely accepted that gossypol and gossypol derivatives inhibit HIV-1 replication by targeting reverse transcriptase. However, from the results of our time-of-addition assay, HIV-1-mediated cell fusion assay and VSV-G pseudotyped virus assay, we demonstrate that the alanine-(-) gossypol derivative ((-)G-Ala) is an effective HIV-1 entry inhibitor. Further mechanistic analysis revealed that (-)G-Ala neither blocks gp120-CD4 binding nor interacts with the HIV-1 co-receptor CXCR4. Results from sandwich ELISA, native-PAGE and circular dichroism (CD) show that (-)G-Ala inhibits the cell fusion-activated gp41 core domain. Moreover, (-)G-Ala binds to the HIV-5-Helix protein and blocking D-peptide (PIE7) binding to the hydrophobic pocket on the surface of the gp41 internal trimeric coiled-coil domain. The contraceptive properties of (-) gossypol and amino acid derivatives of (-) gossypol are also discussed. Collectively, our results indicate that (-)G-Ala may bind to the gp41 hydrophobic pocket and block the formation of the cell fusion-activated gp41 core to inhibit HIV-1-mediated membrane fusion and subsequent viral entry.
authors.affiliation: The College of Life Sciences, State Key Laboratory of Virology, Modern Virology Research Center, Wuhan University, Wuhan 430072, China.
authors.forename: Tai
authors.initials: T
authors.lastname: An
authors.forename: Wenjie
authors.initials: W
authors.lastname: Ouyang
authors.forename: Wei
authors.initials: W
authors.lastname: Pan
authors.forename: Deyin
authors.initials: D
authors.lastname: Guo
authors.forename: Jurong
authors.initials: J
authors.lastname: Li
authors.forename: Longlong
authors.initials: L
authors.lastname: Li
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
authors.forename: Shuwen
authors.initials: S
authors.lastname: Wu
authors.forename: Po
authors.initials: P
authors.lastname: Tien
mesh_terms: D000596:Amino Acids / Q000737:chemistry* / Q000494:pharmacology* / Q000633:toxicity; D002460:Cell Line; D002942:Circular Dichroism; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006072:Gossypol / Q000031:analogs & derivatives* / Q000494:pharmacology* / Q000633:toxicity; D015700:HIV Envelope Protein gp41 / Q000037:antagonists & inhibitors; D023581:HIV Fusion Inhibitors / Q000737:chemistry* / Q000494:pharmacology* / Q000633:toxicity; D015497:HIV-1 / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D011485:Protein Binding; D053586:Virus Internalization / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000596:Amino Acids; D015700:HIV Envelope Protein gp41; D023581:HIV Fusion Inhibitors; C514787:gp41 protein, Human immunodeficiency virus 1; D006072:Gossypol