A synergy of estradiol with leptin modulates the long non-coding RNA NEAT1/ mmu-miR-204-5p/IGF1 axis in the uterus of high-fat-diet-induced obese ovariectomized mice

Abstract

Obesity increases the risk of developing cancers for both males and females. This study investigated potential crosstalk between estradiol and leptin signaling pathways within the endometrium of high-fat-diet-induced obese ovariectomized mice to gain insight into possible links between obesity and endometrial cancer. We administered 17-β estradiol (0.2 μg/mouse subcutaneously) and/or recombinant mouse leptin (1 μg/g Bwt intraperitoneally.,) for 20 h to high-fat-diet-induced obese ovariectomized mice. The uterine tissues of experimental animals after treatments were studied by histological, immunohistochemical, quantitative real-time PCR (gene/miRNAs), and methylation-specific PCR analyses. Quantitative real-time PCR analysis revealed significantly increased expression of Cyclin d1, Esr1, Igf1, Igfbp2, Vegf, Oct4, and Pgr after estradiol and leptin co-treatment. Methylation-specific PCR results indicated that the hormonal dependent transcriptional regulation of Vegf, Igf1, and Pgr is independent of promoter methylation. The decreased expression of mmu- miR-204-5p after estradiol and leptin treatments correlated with the increased expression of long non-coding RNA Neat1. Insilico analysis confirmed the interaction of Neat1 and mmu- miR-204-5p and gene targets of mmu-miR-204-5p, including Igf1 were analyzed in this study. Immunohistochemical analyses revealed subcellular localization and increased expression of ESR, VEGF, phospho-Estrogen Receptor-α (pTyr537), and LEPR proteins following estradiol and leptin exposure. Overall, the data from our in vivo studies suggest the regulation of Neat1-mmu-miR-204−5p- Igf1 axis and associated gene expression changes in uterine tissue after estradiol and leptin co-treatment. In humans, long-term exposure to estradiol and leptin can alter endometrial homeostasis through the NEAT1-miR-204−5p-Igf1 axis and favor carcinogenic pathways, which provide mechanistic insight into the obesity-associated endometrial cancer.