Molecular Mechanism Of Inhibitory Effect Of Lipoxin A₄ On Local Estrogen Metabolizing Enzymes In Endometriosis

Object: Endometriosis is a estrogen dependence and inflammatory diseases,to investigate the mechanism of LXA₄ whether through the regulation of the synthesis of estrogen metabolism key enzyme to regulate local estrogen;whether intervenephosphorylation signal pathwayinduced by inflammatory factors,analysis the mechanism that LXA₄ inhibition endometriosis.Methods:1.Analysis of the expression of estrogen synthesis related protein COX-2,CYP19 A and HSD17B2 in normal endometrium,paired eutopic endometrium and ectopic lesions lesions by q RT-PCR and Western blot.2.In cell model of primary ectopic stromal cells（ESCs）,the expression of COX-2 and CYP19 A in ESCs by IL-1β were detected by q RT-PCR and Western blot.3.Western blot test was used to detect the expression of IL-1β-induced COX-2 and CYP19 A in ESCs with different concentrations of LXA₄ and Boc-2.4.To investigate the mechanism of IL-1β-induced COX-2 expression in ESCs.Detection of IL-1β induces the phosphorylation of MAPK signaling pathway in ESCs,including ERK,JNK,p38 three pathway.Then blocking three pathway,including ERK inhibitors（PD99805）,JNK inhibitor（SP600125）,p38 MAPK inhibitor（SB203580）,to determine the expression of COX-2.5.Western blot test was used to detect IL-1β-induced the phosphorylation of MAPK signaling pathway with different concentrations of LXA₄.6.BABL/c female mice were used to create endometriosis mouse model,after treatment of LXA₄ and LXA₄ receptor inhibitors,the change of the growth of ectopic lesions,inflammatory cytokines,COX-2 and p38 MAPK of ectopic endometriosis lesions by q RT-PCR,Western blot and ELISA.Result:1.Overexpression of COX-2 and CYP19 A were observed in ectopic endometrium of endometriosis patients compared to normal endometrium of controls.2.IL-1β induced the expression of COX-2 and CYP19 A in a concentration-and time-dependent manner.3.LXA₄ efficiently suppressed IL-1β-induced COX-2 and CYP19 A protein expression in ectopic endometriosis cells（ESCs）via its receptor,formyl peptide receptor 2（FPR2/ALX）.4.IL-1β induced the phosphorylation of ERK,JNK and p38 MAPK in the ESCs,and the expression of COX-2 is down regulated after blockingp38 MAPK pathway.5.Pretreatment of ESCs with LXA₄ inhibited IL-1β-induced p38 MAPK phosphorylation.6.Inflammation and MAPKs were involved in COX-2 expression in the pathophysiology of endometriosis.LXA₄ suppressed IL-1β-induced COX-2 expression through inhibiting the p38 MAPK signaling protein.Conclusion:1.The abnormal expression of the key enzymes of estrogen metabolism in ectopic endometrium leads to the high synthesis and low inactivation of estrogen,which results in the formation of local high estrogen concentration and the development of endometriosis2.Expression of key enzymes of local estrogen metabolism increases inflammation,promote the synthesis of estrogen and its receptor;LXA₄ in FPR2/ALX mediated anti-inflammatory action,and the expression of estrogen metabolism key enzyme,affecting the synthesis of estrogen.3.MAPK signaling pathway plays an important role in mediating inflammation and the expression of COX-2 the key enzyme of local estrogen synthesis.LXA₄ inhibits inflammation and local estrogen synthesis through p38 MAPK signaling pathway.