Structural determinants for activity of the antidepressant vortioxetine at human and rodent 5-HT 3 receptors.
Uriel López-SánchezLachlan Jake MunroLucy Kate LadefogedAnders Juel PedersenChristian Colding BrunSigne Meisner LyngbyDelphine BaudCéline Juillan-BinardMiriam Grønlund PedersenSarah C R LummisBenny Bang-AndersenBirgit SchiøttChristophe ChipotGuy SchoehnJacques NeytonFrancois DehezHugues NuryAnders S KristensenPublished in: Nature structural & molecular biology (2024)
Vortioxetine (VTX) is a recently approved antidepressant that targets a variety of serotonin receptors. Here, we investigate the drug's molecular mechanism of operation at the serotonin 5-HT 3 receptor (5-HT 3 R), which features two properties: VTX acts differently on rodent and human 5-HT 3 R, and VTX appears to suppress any subsequent response to agonists. Using a combination of cryo-EM, electrophysiology, voltage-clamp fluorometry and molecular dynamics, we show that VTX stabilizes a resting inhibited state of the mouse 5-HT 3 R and an agonist-bound-like state of human 5-HT 3 R, in line with the functional profile of the drug. We report four human 5-HT 3 R structures and show that the human receptor transmembrane domain is intrinsically fragile. We also explain the lack of recovery after VTX administration via a membrane partition mechanism.