EETs Reduction Contributes to Granulosa Cell Senescence and Endometriosis‐Associated Infertility via the PI3K/AKT/mTOR Signaling Pathway

Abstract We aimed to examine abnormal oxidative lipid levels and their related mechanisms in EM‐associated infertility. Through liquid chromatography tandem mass spectrometry analysis, decreased levels of epoxyeicosatrienoic acids (EETs), which have antioxidant and anti‐senescence effects are observed, in EM patient follicular fluid samples. EET levels are positively correlated with in vitro fertilization outcomes. Lower 14, 15‐EET concentrations led to a decreased GC antioxidant capacity, reduced ATP production, reactive oxygen species (ROS) accumulation in oocytes, and abnormal cumulus‐oocyte complex (COC) expansion, ultimately resulting in decreased fertility. Elevated soluble epoxide hydrolase (EPHX2) expression in EM‐GCs is the main reason for EET reduction in EM follicular fluid. Inhibiting EPHX2 in vivo or in vitro can reverse these observed abnormalities by upregulating EETs. 14, 15‐EET treatment alleviated GC senescence and improved fertility by inhibiting excessive PI3K/AKT/mTOR signaling pathway activation in EM‐GCs, with BEZ‐235‐mediated inhibition of this pathway significantly alleviating ROS‐induced cell senescence and abnormal COC expansion. Oxidative stress‐induced decreased EZH2/H3K27Me3 histone methylation led to elevated EPHX2 expression patterns in EM‐GCs. Decreased 14, 15‐EET levels resulted in ROS accumulation, reduced EZH2 enzymatic activity, less EPHX2/H3K27Me3 histone methylation, and increased EPHX2 protein expression levels, which further reduced 14, 15‐EET levels in a vicious feedback loop.