Effects Of Prostaglandin E₂ Receptors-G Protein-cAMP Coupled Signal Transduction And The Function On Fibroblast-like Synoviocytes Of Human By TNF-α And The Effects Of Paeoniflorin

OBJECTIVE To investigate the effects of paeoniflorin (Pae) on the proliferation and prostaglandin E₂(PGE₂), interleukin-1β(IL-1β) productions of fibroblast-like synoviocy- tes (FLS) of human under the stimulation of tumor necrosis factor-α(TNF-α);To investi- gate prostaglandinE₂ receptor (EP), inhibitory subunit of G protein(Gαi₂), stimulatory subunit of G protein(Gαs), cyclic adenosine monophosphate(cAMP) productions of FLS of human under the stimulation of TNF-α.we investigated effects of Pae on the express- ion of EP and the G-protein coupled signal transduction pathway in human synoviocyt- es and its anti-proliferation action.METHODS We investigated the expression changes of PGE₂,IL-1β,cAMP and the effect of Paeoniflorin in human fibroblast-like synoviocytes (FLS) induced by TNF-α. The proliferation of FLS was detected with 3-(4,5-dimethylthiazol-2-thiazolyl)-2, 5-dip- henyl-2H-tetrazolium bromide (MTT).IL-1βproduction of synoviocytes was measured by radioimmunoassay assay. PGE₂, cAMP were measured by ELISA.The expressions of Gαi₂,Gαs and EP₂ were detected by fluoroimmunoassay.RESULTS1.The effect of Pae on inhibiting FLS proliferation and IL-1,PGE₂ level of FLS induced by TNF-α.From this study, we found that proliferation and the level of IL-1β,PGE₂ in human FLS increased when induced by TNF-α(0.02,0.2,2.0,20μg·L^-1), and Pae (10-8-10-4 mol·L^-1) in vitro could reduce proliferation and the high level of IL-1β,PGE₂. These results demonstrated that an important characteristic effect of Pae anti-inflammation is inhibiting accentuates secretion of FLS and exerting anti-proliferation action.2.Modulating the expression of EP₂ subtypes, maintaining the balance of Gαs/Gαi, and recovering the PGE₂-EP-G protein-AC-cAMP signal transduction pathway of human FLS is probablly one of the most important molecule mechanisms of Pae preventing RA.From this study, we found that the level of cAMP in human FLS reduced when in- duced by TNF-α(0.02,0.2,2.0,20μg·L^-1), and Pae(10-8-10-4 mol·L^-1) in vitro could recover the level of cAMP. The result of fluoroimmunoassay demonstrated that stimula- tion by TNF-α(20μg·L^-1)could inhibit the EP₂ subtypes, Pae(10-8 mol·L^-1) could recover the expression of EP₂. Stimulation by TNF-α(20μg·L^-1)could inhibit the expression of Gαs,improve the expression of Gαi₂,Pae(10-8 mol·L^-1)could recover the expressions of Gαs and Gαi₂, recover the balance of Gαs/Gαi.These results demonstrated that modula- ting the expression of EP₂ subtypes, maintaining the balance of Gαs/Gαi, and recovering the PGE₂-EP-G protein-AC-cAMP signal transduction is probablly one of the most imp- ortant molecule mechanisms of Pae preventing RA.CONCLUSIONS1.The important characteristic effect of Pae anti-inflammation is inhibiting accentuates secretion of FLS and exerting anti-proliferation action.2.Pae obviously inhibited the expression of Gαi₂, improved the expressions of Gαs, EP₂ and recovered the balance of Gαs/Gαi. recovering the PGE₂-EP-G protein-AC-cAMP signal transduction pathway of human FLS probablly is one of the most important molecule mechanisms of Pae preventing RA.