TY - JOUR T1 - Ginsenosides act as positive modulators of P2X4 receptors JF - Molecular Pharmacology JO - Mol Pharmacol DO - 10.1124/mol.118.113696 SP - mol.118.113696 AU - Kshitija Dhuna AU - Matthew Felgate AU - Stefan M Bidula AU - Samuel Walpole AU - Lucka Bibic AU - Brett A Cromer AU - Jesus Angulo AU - Julie Sanderson AU - Martin J Stebbing AU - Leanne Stokes Y1 - 2018/01/01 UR - http://molpharm.aspetjournals.org/content/early/2018/12/13/mol.118.113696.abstract N2 - We investigated the selectivity of protopanaxadiol ginsenosides from Panax ginseng acting as positive allosteric modulators on P2X receptors. ATP-induced responses were measured in stable cell lines over-expressing human P2X4 using a YOPRO-1 dye uptake assay, intracellular calcium measurements, and whole cell patch clamp recordings. Ginsenosides CK and Rd were demonstrated to enhance ATP responses at P2X4 by ~2-fold, similar to potentiation by the known positive modulator ivermectin. Investigations into the role of P2X4 in mediating a cytotoxic effect showed that only P2X7 expression in HEK-293 cells induces cell death in response to high concentrations of ATP, and that ginsenosides can enhance this process. Generation of a P2X7-deficient clone of BV-2 microglial cells using CRISPR/Cas9 gene editing enabled an investigation of endogenous P2X4 in a microglial cell line. Compared to parental BV-2 cells, P2X7-deficient BV-2 cells showed minor potentiation of ATP responses by ginsenosides, and insensitivity to ATP- or ATP+ginsenoside-induced cell death, indicating a primary role for P2X7 receptors in both of these effects. Computational docking to a homology model of human P2X4, based on the open state of zfP2X4, yielded evidence of a putative ginsenoside binding site in P2X4 in the central vestibule region of the large ectodomain. ER -