Transient receptor potential vanilloid-1 participates in the inhibitory effect of ginsenoside Rg1 on capsaicin-induced interleukin-8 and prostaglandin E2 production in HaCaT cells.
OBJECTIVE
Ginsenoside Rg1 (GRg1), one of the major active constituents of Panax notoginseng, has shown anti-inflammatory and antinocioceptic activity, but its role in keratinocytes needs further study. We have examined the inhibitory effect of GRg1 on transient receptor potential vanilloid-1 (TRPV1) activation in keratinocyte HaCaT cells and explored its involved mechanism.


METHODS
HEK 293T cells over-expressing exogenous TRPV1 were constructed and named HEK 293T-TRPV1 cells. The effects of GRg1 on production of interleukin-8 (IL-8) and prostaglandin E(2) (PGE(2) ), calcium influx, the expression of cyclooxygenase-2 (COX-2) and nuclear factor-κB (NF-κB) transcriptional activity in HEK 293T-TRPV1 and HaCaT cells were examined by ELISA, Fluo 3-AM fluorescence probe, Western blot and Dual-Luciferase Reporter Assay, respectively.


RESULTS
The results showed that GRg1 blocked intracellular calcium by both capsaicin and proton activation in a TRPV1-dependent manner. Furthermore, GRg1 inhibited the expression of COX-2 and NF-κB transcriptional activity induced by capsaicin in keratinocytes. The inhibitory effect of GRg1 was similar to capsazepine, an antagonist of TRPV1. More importantly, GRg1 dose-dependently inhibited capsaicin-induced PGE(2) and IL-8 secretion in HaCaT cells and HEK 293T-TRPV1 cells.


CONCLUSIONS
These data showed that GRg1 could inhibit TRPV1 mediated responses in HaCaT cells, indicating that GRg1 acted as a TRPV1 antagonist.
Department of Pharmacy, Changhai Hospital, Second Military Medical University, Shanghai, China.
Jin
J
Huang
Li
L
Ding
Duo
D
Shi
Jin-Hong
JH
Hu
Quan-Gang
QG
Zhu
Shen
S
Gao
Lei
L
Qiu
D002118:Calcium / Q000378:metabolism; D002211:Capsaicin / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D002478:Cells, Cultured; D002491:Central Nervous System Agents / Q000494:pharmacology*; D051546:Cyclooxygenase 2 / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism*; D004365:Drugs, Chinese Herbal / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D036145:Ginsenosides / Q000494:pharmacology*; D057809:HEK293 Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism*; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D050916:TRPV Cation Channels / Q000378:metabolism*
D002491:Central Nervous System Agents; D004365:Drugs, Chinese Herbal; D036145:Ginsenosides; D016209:Interleukin-8; D016328:NF-kappa B; D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; D051546:Cyclooxygenase 2; D015232:Dinoprostone; C035054:ginsenoside Rg1; D002211:Capsaicin; D002118:Calcium