Integrated bioinformatics analysis uncovers characteristic genes and molecular subtyping system for endometriosis.

Objective: Endometriosis is a chronic inflammatory estrogen-dependent disease with the growth of endometrial tissues outside the uterine cavity. Nevertheless, the etiology of endometriosis is still unclear. Integrated bioinformatics analysis was implemented to reveal the molecular mechanisms underlying this disease. Methods: A total of four gene expression datasets (GSE7305, GSE11691, GSE23339, and GSE25628) were retrieved from the GEO, which were merged into a meta-dataset, followed by the removal of batch effects via the sva package. Weighted gene co-expression network analysis (WGCNA) was implemented, and endometriosis-related genes were screened under normal and endometriosis conditions. Thereafter, characteristic genes were determined via Lasso analysis. The diagnostic performance was estimated via receiver operating characteristic curves, and epigenetic and post-transcriptional modifications were analyzed. Small molecular compounds were predicted. Unsupervised clustering analysis was conducted via non-negative matrix factorization algorithm. The enriched pathways were analyzed via gene set enrichment analysis or GSVA. Immune features were evaluated according to immune-checkpoints, HLA, receptors, chemokines, and immune cells. Results: In total, four characteristic genes (BGN, AQP1, ELMO1, and DDR2) were determined for endometriosis, all of which exhibited the favorable efficacy in diagnosing endometriosis. Their aberrant levels were modulated by epigenetic and post-transcriptional modifications. In total, 51 potential drugs were predicted against endometriosis. The characteristic genes exhibited remarkable associations with immunological function. Three subtypes were classified across endometriosis, with different mechanisms and immune features. Conclusion: Our study reveals the characteristic genes and novel molecular subtyping of endometriosis, contributing to the early diagnosis and intervention in endometriosis.

Lipoxin A4 Suppresses Estrogen-Induced Epithelial-Mesenchymal Transition via ALXR-Dependent Manner in Endometriosis.

OBJECTIVE: Epithelial-mesenchymal transition (EMT) is essential for embryogenesis, fibrosis, and tumor metastasis. Aberrant EMT phenomenon has been reported in endometriotic tissues of patients with endometriosis (EM). In this study, we further investigated the molecular mechanism of which lipoxin A4 (LXA4) suppresses estrogen (E2)-induced EMT in EM. STUDY DESIGN: The EMT markers were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot in eutopic endometrial epithelial cells (EECs) or investigated by immunohistochemistry and qRT-PCR in endometriotic lesion of EM mice. The invasion and migration under different treatments were assessed by transwell assays with or without Matrigel. The messenger RNA (mRNA) and activities of matrix metalloproteinase 2 (MMP-2) and MMP-9 were determined by qRT-PCR and gelatin zymography, respectively. Luciferase reporter assay was used to measure the activity of zinc finger E-box binding homeobox 1(ZEB1) promoter. The level of E2 in endometriotic tissues was assessed by enzyme-linked immunosorbent assay. RESULTS: In eutopic EECs, stimulatory effects of E2 on EMT progress, migration, and invasion were all diminished by LXA4. Lipoxin A4 reduced E2-induced ZEB1 promoter activity. Lipoxin A4 also attenuated the phosphorylation of extracellular signal-regulated kinase and p38 mitogen-activated protein kinase induced by E2. Co-incubation with Boc-2 rather than DMF antagonized the influence of LXA4. Animal experiments showed that LXA4 inhibited the EMT progress, MMP expression, and proteinase activities of endometriotic lesion in an LXA4 receptor (ALXR) manner, which suppressed the progression of EM. ZEB1 mRNA expression was upregulated and well correlated with E2 level in human endometrium. CONCLUSION: Lipoxin A4 suppresses E2-induced EMT via ALXR-dependent manner in eutopic EECs, which reveals a novel biological effect of LXA4 in EM.

Effect of interleukin-1ß and lipoxin A4 in human endometriotic stromal cells: Proteomic analysis.

AIM: Lipoxin A4 (LXA4 ) can function as an endogenous 'breaking signal' in inflammation and plays an important role in the progression of endometriosis. The proteome responses to interleukin-1ß (IL-1ß) or LXA4 in human endometriotic stromal cells (ESC) are not well understood. METHODS: In this study, primary ESC were cultured from ovarian endometriosis tissue. Three groups were established: the control group; the IL-1ß stimulation group; and the IL-1ß and LXA4 incubation group. Proteins were assessed on 2-D polyacrylamide gel electrophoresis (2D-PAGE), and differentially expressed protein spots were further identified on matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MALDI-TOF-MS). Wound healing and transwell assays were performed to assess the migration and invasion of ESC after treatment. RESULTS: In total, 40 differentially expressed protein spots were identified successfully on MALDI-TOF-MS. The proteins identified were related to cell structure, metabolism, signal transduction, protein synthesis and membrane structure, processes that may be involved in the development of endometriosis. Vinculin and IL-4 were further analyzed on western blot and quantitative real-time polymerase chain reaction. Moreover, LXA4 could suppress the migration and invasion of ESC induced by IL-1ß. CONCLUSION: LXA4 may inhibit the progression of endometriosis partly by lowering or raising the effect of IL-1ß, mediated via some inflammation-related proteins (e.g. vinculin) and immune response-related protein (e.g. IL-4) in vitro.