Identification of a Calcium Signalling Pathway ofS-[6]-Gingerol in HuH-7 Cells

Abstract

Calcium signals in hepatocytes control cell growth, proliferation, and death. Members of the transient receptor potential (TRP) cation channel superfamily are candidate calcium influx channels. NFκB activation strictly depends on calcium influx and often induces antiapoptotic genes favouring cell survival. Previously, we reported thatS-[6]-gingerol is an efficacious agonist of the transient receptor potential cation channel subfamily V member 1 (TRPV1) in neurones. In this study, we tested the effect ofS-[6]-gingerol on HuH-7 cells using the Fluo-4 calcium assay, RT-qPCR, transient cell transfection, and luciferase measurements. We found thatS-[6]-gingerol induced a transient rise in[Ca2+]iin HuH-7 cells. The increase in[Ca2+]iinduced byS-[6]-gingerol was abolished by preincubation with EGTA and was also inhibited by the TRPV1 channel antagonist capsazepine. Expression of TRPV1 in HuH-7 cells was confirmed by mRNA analysis as well as a test for increase of[Ca2+]iby TRPV1 agonist capsaicin and its inhibition by capsazepine. We found thatS-[6]-gingerol induced rapid NFκB activation through TRPV1 in HuH-7 cells. Furthermore,S-[6]-gingerol-induced NFκB activation was dependent on the calcium gradient and TRPV1. The rapid NFκB activation byS-[6]-gingerol was associated with an increase in mRNA levels of NFκB-target genes: cIAP-2, XIAP, and Bcl-2 that encode antiapoptotic proteins.