METTL3-regulated m6A modification impairs the decidualization of endometrial stromal cells by regulating YTHDF2-mediated degradation of FOXO1 mRNA in endometriosis-related infertility

Abstract

Background Endometriosis-related infertility is a common worldwide reproductive health concern. Despite ongoing research, the causes of infertility remain unclear. Evidence suggests that epigenetic regulation is crucial in reproduction. However, the role of N6-methyladenosine (m6A) modification of RNA in endometriosis-related infertility requires further investigation. Methods We examined the expression of m6A and methyltransferase-like 3 (METTL3) in endometrial samples taken from normal fertile women in the proliferative phase (the NP group) or the mid-secretory phase (the NS group) or from women with endometriosis-related infertility at the mid-secretory phase (the ES group). We treated primary endometrial stromal cells (ESCs) with medroxyprogesterone acetate and 8-Bromo-cyclic adenosine monophosphate for in vitro decidualization and detected the expression of m6A, METTL3, and decidual markers. We analyzed the expression of m6A, METTL3, and forkhead box O1 (FOXO1) in ESCs from normal fertile women (the ND group) or women with endometriosis-related infertility (the ED group). We also assessed the expression of m6A, METTL3, and decidual markers, as well as the embryo adhesion rate, upon METTL3 overexpression or knockdown. Additionally, we investigated the role of METTL3 in embryo implantation in vivo by applying mice with endometriosis. Furthermore, we performed RNA stability assays, RNA immunoprecipitation (RIP), and methylated RIP assays to explore the mechanisms underlying the regulation of FOXO1 by METTL3-mediated m6A. Results The expression of m6A and METTL3 was reduced only in the NS group; the NP and ES groups demonstrated increased m6A and METTL3 levels. m6A and METTL3 levels decreased in ESCs with prolonged decidual treatment. Compared to the ND group, m6A and METTL3 levels in the ED group increased after decidual treatment, whereas the expression of FOXO1 decreased. METTL3 overexpression suppressed the expression of decidual markers and embryo implantation in vitro; METTL3 knockdown exhibited the opposite effect. Inhibition of METTL3 promoted embryo implantation in vivo. Furthermore, we observed that METTL3-mediated m6A regulated the degradation of FOXO1 mRNA through YTHDF2, a m6A binding protein. Conclusions METTL3-regulated m6A promotes YTHDF2-mediated decay of FOXO1 mRNA, thereby affecting cellular decidualization and embryo implantation. These findings provide novel insights into the development of therapies for women with endometriosis-related infertility.

Methyltransferase‐like 3 mediated RNA m6A modifications in the reproductive system: Potentials for diagnosis and therapy

“…Besides, decidualization is a key step for establishing receptivity that provides appropriate conditions for embryo implantation, abnormal of which usually causes RIF or infertility 36,37 . Study found that the abnormal expression of METTL3 leads to the degradation of FOXO1 mRNA through binding to YTHDF2, which subsequently affecting cellular decidualization and embryo implantation 38 (Figure 2). Collectively, the upregulated expression of METTL3 triggers the occurrence and progression of asthenozoospermia, RIF, and infertility, indicating that a high level of METTL3 may serve as a risk indicator for these diseases as well as a potential diagnostic biomarker and therapeutic target in clinical settings.…”

Bioinformatic analysis reveals endoplasmic reticulum stress-related molecular cluster and immune characterization in endometriosis：implications for disease subtyping and therapeutic strategies

“…The immunohistochemical staining of para n-embedded sections from all samples underwent morphological screening examination and was conducted following the established protocol previously described in the literature [33]. Brie y, the sections were stained with the primary antibody against F8 (1:500, a nity, USA), VCAM1(1:200, Proteintech, Wuhan, China), VWF (1:400, Proteintech, Wuhan, China), and EPAS1(1:50, Proteintech, Wuhan, China) and then scanned with a digital scanner.…”

Regulated Cell Death in Endometriosis

“…In fact, progesterone acts primarily on target genes through PRB, which antagonizes estrogen-induced endometrial epithelial cell proliferation through PRA [30]. This abnormal progesterone receptor change may affect the normal decidualization of the endometrium, making the endometrium less receptive, and may be one of the causes of infertility in patients with endometriosis [31]. In addition, the level of estrogen in endometriosis is abnormally high, and the enzymes related to estrogen synthesis, such as aromatase and HSD17β1 (Hydroxysteroid 17-Beta Dehydrogenase 1), are also highly expressed or increased in endometriosis lesions.…”