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

Xiao-Hong Li,Yi-Ming Li,Colin C Duke,Kristine C Y Mcgrath,Sravan Mandadi,Alison K Heather,Basil D Roufogalis,Van H Tran

doi:10.1155/2013/951758

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 that S-[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 of S-[6]-gingerol on HuH-7 cells using the Fluo-4 calcium assay, RT-qPCR, transient cell transfection, and luciferase measurements. We found that S-[6]-gingerol induced a transient rise in [Ca2+]i in HuH-7 cells. The increase in [Ca2+]i induced by S-[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+]i by TRPV1 agonist capsaicin and its inhibition by capsazepine. We found that S-[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 by S-[6]-gingerol was associated with an increase in mRNA levels of NFκB-target genes: cIAP-2, XIAP, and Bcl-2 that encode antiapoptotic proteins.

Highlights

The liver plays a central role in intermediary metabolism, the detoxification of endogenous and exogenous compounds, and whole body homeostasis
We report for the first time that the principle component of ginger, S-[6]-gingerol, activates the TRPV1 channel in HuH-7 cells to induce a transient rise in intracellular calcium concentration ([Ca2+]i)
This regulates a rapid increase in nuclear factor κB (NFκB) activation that, in turn, is associated with an increase in the expression of the NFκB-regulated genes, cIAP-2, XIAP, and Bcl-2

Summary

Introduction

The liver plays a central role in intermediary metabolism, the detoxification of endogenous and exogenous compounds, and whole body homeostasis. The predominant cell type in the liver is the hepatocyte, which comprises about 70% of all cells [1, 2]. Calcium signals in hepatocyte regulate glucose, fatty acid, amino acid, and xenobiotic metabolism. They mediate essential cellular functions, including cell movement, secretion, and gene expression, thereby controlling cell growth, proliferation, and cell death [3,4,5,6,7]. Transient receptor potential (TRP) channels most likely account for most of the receptor-activated calcium permeable channels in hepatocytes, the molecular identification and function of only a few of the channels have been reasonably well established [8]

Methods

Results

Conclusion