Background and Purpose
Lipoxins can function as endogenous ‘breaking signals’ in inflammation and play important roles in the progression of endometriosis. In this study, we further investigated the molecular mechanism by which lipoxin A4 (LXA4) suppresses the development of endometriosis.
Experimental Approach
Primary endometriotic stromal cells (ESCs) were treated with IL‐1β, or pre‐incubated with LXA4 before incubation with IL‐1β. The LXA4 receptor (ALX receptor) antagonist Boc‐2 and gene‐silencing approaches were used to study the involvement of the ALX receptor in anti‐inflammatory signalling responses in ESCs. An animal model of endometriosis was induced in BALB/c mice by i.p. injection of an endometrium‐rich fragment.
Key Results
Decreased levels of LXA4 and 15‐LOX‐2 expression but increased expression of AXL receptors were observed in endometriotic tissues. LXA4 inhibited the release of inflammatory factors and phosphorylation of p38 MAPK in IL‐1β‐induced ESCs, an effect mediated by ALX receptors. LXA4 inhibited the proliferation of ESCs, as indicated by reduced DNA replication, caused G0/G1 phase cell cycle arrest and down‐regulated the expression of proliferating cell nuclear antigen in ESCs. LXA4 also attenuated the invasive activity of ESCs mainly by suppressing the expression and activity of MMP‐9. In vivo, we further confirmed that LXA4 could inhibit the progression of endometriosis by acting as an anti‐inflammatory.
Conclusions and Implications
LXA4 exerted anti‐inflammatory, anti‐proliferative and anti‐invasive effects on endometriosis through a mechanism that involved down‐regulating the activities of p38 MAPK, which was mediated by ALX receptors.
BackgroundGout is considered one of the most painful acute conditions caused by deposition of monosodium urate (MSU) crystals within joints. Recent studies have shown that interleukin (IL)-1β is a key inflammatory mediator in acute gouty arthritis (GA), and its level is regulated by microRNAs (miRNAs). However, the molecular mechanisms of the regulation remain unclear.MethodsA miRNA microarray was used to analyze the miRNA expression profiles in peripheral white blood cells (WBCs) of patients with GA. THP-1 cells were transfected with miRNA mimics, stimulated by MSU crystals, and then subjected to quantitative real-time polymerase chain reaction or Western blot analysis. Levels of IL-1β, IL-8, and tumor necrosis factor (TNF)-α in culture supernatants of THP-1 cells were measured by enzyme-linked immunosorbent assay. A luciferase reporter assay was conducted to confirm the interaction of miRNA and IL-1β 3′-untranslated regions (UTRs).ResultsCombining bioinformatics and miRNA expression profiles, we found five miRNAs (hsa-miR-30c-1-3p, hsa-miR-488-3p, hsa-miR-550a-3p, hsa-miR-663a, and hsa-miR-920) that possibly target IL-1β. Then, we demonstrated that miR-488 and miR-920 were significantly decreased in the WBCs of patients with GA and that MSU crystals could inhibit expression of miR-488 and miR-920. Upregulation of miR-488 and miR-920 could suppress MSU-induced IL-1β protein expression in THP-1 cells, but no significant difference in IL-1β messenger RNA levels was observed. Moreover, we found that miR-488 and miR-920 could directly target the 3′-UTR of IL-1β. Overexpression of miR-488 and miR-920 could significantly inhibit the gene and protein expression of IL-8 and TNF-α in MSU-induced THP-1 cells.ConclusionsThis study demonstrates the roles of miR-488 and miR-920 in regulating the production of proinflammatory cytokines in the pathogenesis of GA. These findings suggest that miR-488 and miR-920 could serve as potential therapeutic targets in the treatment of GA.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-017-1418-6) contains supplementary material, which is available to authorized users.
Problem:The role of the long non-coding RNA (lncRNA) actin filament associated protein 1 antisense RNA1 (AFAP1-AS1) in the etiology of endometriosis is unknown.
Method of Study: Expression of epithelial-mesenchymal transition (EMT) markerswas quantified using qRT-PCR, immunohistochemistry, and Western blotting. The proliferation, migration, and invasion of ectopic endometrial epithelial cells and Ishikawa cells were evaluated by MTT, EdU, wound healing, and transwell assays.Inflammatory cytokine levels were detected by ELISA. Luciferase assays were used to measure activity of the ZEB1 promoter site pGL3-P886.Results: AFAP1-AS1 levels were much higher in ectopic endometrial tissues than that in eutopic tissues. Expression of ZEB1, E-cadherin, and keratin was obviously higher in eutopic tissues than those in ectopic tissues. In contrast, expression of vimentin and N-cadherin was significantly lower in eutopic tissue than those in ectopic tissues.After knockdown of AFAP1-AS1, the morphology of endometrial epithelial cells varied from spindle fiber shaped to polygon epithelioid and proliferation, migration, and invasion were each inhibited. The knockdown of AFAP1-AS1 significantly inhibited expression from promoter site pGL3-P886 of the EMT-related transcription factor ZEB1. The size of subcutaneous tumours in nude mice was significantly reduced after down-regulation of AFAP1-AS1 expression.
Conclusion:Higher expression of AFAP1-AS1 positively correlated with greater EMT in ectopic endometrium of patients with endometriosis. Knockdown of AFAP1-AS1 inhibited E2-induced activity of promoter site pGL3-P886 of transcription factor ZTB1, suggesting that AFAP1-AS1 knockdown inhibited growth of endometrial epithelial cells and that pathogenesis may be correlated with EMT.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.