title: Molecular Determinants of GS-9620-Dependent TLR7 Activation.
abstract: GS-9620 is an orally administered agonist of Toll-like receptor (TLR)7 currently being evaluated in clinical studies for the treatment of chronic HBV and HIV patients. GS-9620 has shown antiviral efficacy in preclinical models of chronic hepadnavirus infection in woodchuck as well as chimpanzee. However, the molecular determinants of GS-9620-dependent activation of TLR7 are not well defined. The studies presented here elucidate GS-9620 subcellular distribution and characterize its molecular interactions with human TLR7 using structure-guided mutational analysis. Based on our results we present a molecular model of TLR7 bound to GS-9620. We also determine that several coding SNPs had no effect on GS-9620-dependent TLR7 activation. In addition, our studies provide evidence that TLR7 exists in a ligand-independent oligomeric state and that, TLR7 activation by GS-9620 is likely associated with compound-induced conformational changes. Finally, we demonstrate that activation of NF-κB and Akt pathways in primary plasmacytoid dendritic cells occur as immediate downstream cellular responses to GS-9620 stimulation. The data presented here further our understanding of the molecular parameters governing TLR7 activation by GS-9620, and more generally by nucleos/tide-related ligands.
authors.affiliation: Department of Biology, Gilead Sciences Inc., Foster City, California, USA.
authors.forename: Indrani
authors.initials: I
authors.lastname: Rebbapragada
authors.affiliation: Department of Biology, Gilead Sciences Inc., Foster City, California, USA.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Birkus
authors.affiliation: Department of Structural Chemistry Gilead Sciences Inc., Foster City, California, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Perry
authors.affiliation: Department of Biology, Gilead Sciences Inc., Foster City, California, USA.
authors.forename: Weimei
authors.initials: W
authors.lastname: Xing
authors.affiliation: Department of Biology, Gilead Sciences Inc., Foster City, California, USA.
authors.forename: HyockJoo
authors.initials: H
authors.lastname: Kwon
authors.affiliation: Department of Biology, Gilead Sciences Inc., Foster City, California, USA.
authors.forename: Stefan
authors.initials: S
authors.lastname: Pflanz
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002478:Cells, Cultured; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D020641:Polymorphism, Single Nucleotide; D011485:Protein Binding; D011621:Pteridines / Q000494:pharmacology*; D051199:Toll-Like Receptor 7 / Q000819:agonists / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D011621:Pteridines; C495348:TLR7 protein, human; D051199:Toll-Like Receptor 7; C582524:vesatolimod