title: Dual inhibition of HIV-1 replication by integrase-LEDGF allosteric inhibitors is predominant at the post-integration stage.
abstract: BACKGROUND
  LEDGF/p75 (LEDGF) is the main cellular cofactor of HIV-1 integrase (IN). It acts as a tethering factor for IN, and targets the integration of HIV in actively transcribed gene regions of chromatin. A recently developed class of IN allosteric inhibitors can inhibit the LEDGF-IN interaction.
  
  
  RESULTS
  We describe a new series of IN-LEDGF allosteric inhibitors, the most active of which is Mut101. We determined the crystal structure of Mut101 in complex with IN and showed that the compound binds to the LEDGF-binding pocket, promoting conformational changes of IN which explain at the atomic level the allosteric effect of the IN/LEDGF interaction inhibitor on IN functions. In vitro, Mut101 inhibited both IN-LEDGF interaction and IN strand transfer activity while enhancing IN-IN interaction. Time of addition experiments indicated that Mut101 behaved as an integration inhibitor. Mut101 was fully active on HIV-1 mutants resistant to INSTIs and other classes of anti-HIV drugs, indicative that this compound has a new mode of action. However, we found that Mut101 also displayed a more potent antiretroviral activity at a post-integration step. Infectivity of viral particles produced in presence of Mut101 was severely decreased. This latter effect also required the binding of the compound to the LEDGF-binding pocket.
  
  
  CONCLUSIONS
  Mut101 has dual anti-HIV-1 activity, at integration and post-integration steps of the viral replication cycle, by binding to a unique target on IN (the LEDGF-binding pocket). The post-integration block of HIV-1 replication in virus-producer cells is the mechanism by which Mut101 is most active as an antiretroviral. To explain this difference between Mut101 antiretroviral activity at integration and post-integration stages, we propose the following model: LEDGF is a nuclear, chromatin-bound protein that is absent in the cytoplasm. Therefore, LEDGF can outcompete compound binding to IN in the nucleus of target cells lowering its antiretroviral activity at integration, but not in the cytoplasm where post-integration production of infectious viral particles takes place.
authors.affiliation: Biodim Mutabilis, Romainville 93230, France. richard.benarous@mutabilis.fr.
authors.forename: Erwann
authors.initials: E
authors.lastname: Le Rouzic
authors.forename: Damien
authors.initials: D
authors.lastname: Bonnard
authors.forename: Sophie
authors.initials: S
authors.lastname: Chasset
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Bruneau
authors.forename: Francis
authors.initials: F
authors.lastname: Chevreuil
authors.forename: Frédéric
authors.initials: F
authors.lastname: Le Strat
authors.forename: Juliette
authors.initials: J
authors.lastname: Nguyen
authors.forename: Roxane
authors.initials: R
authors.lastname: Beauvoir
authors.forename: Céline
authors.initials: C
authors.lastname: Amadori
authors.forename: Julie
authors.initials: J
authors.lastname: Brias
authors.forename: Sophie
authors.initials: S
authors.lastname: Vomscheid
authors.forename: Sylvia
authors.initials: S
authors.lastname: Eiler
authors.forename: Nicolas
authors.initials: N
authors.lastname: Lévy
authors.forename: Olivier
authors.initials: O
authors.lastname: Delelis
authors.forename: Eric
authors.initials: E
authors.lastname: Deprez
authors.forename: Ali
authors.initials: A
authors.lastname: Saïb
authors.forename: Alessia
authors.initials: A
authors.lastname: Zamborlini
authors.forename: Stéphane
authors.initials: S
authors.lastname: Emiliani
authors.forename: Marc
authors.initials: M
authors.lastname: Ruff
authors.forename: Benoit
authors.initials: B
authors.lastname: Ledoussal
authors.forename: François
authors.initials: F
authors.lastname: Moreau
authors.forename: Richard
authors.initials: R
authors.lastname: Benarous
mesh_terms: D002460:Cell Line; D018360:Crystallography, X-Ray; D019427:HIV Integrase / Q000737:chemistry / Q000378:metabolism*; D019428:HIV Integrase Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D015497:HIV-1 / Q000187:drug effects* / Q000502:physiology*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D016662:Virus Integration / Q000187:drug effects*; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D019428:HIV Integrase Inhibitors; D036341:Intercellular Signaling Peptides and Proteins; C119380:lens epithelium-derived growth factor; D019427:HIV Integrase; C514801:p31 integrase protein, Human immunodeficiency virus 1