• This article uses bioinformatic methods to identify target genes for the treatment of endometriosis.

The endometriosis prevalence seems to be considerably higher in sub-fertile women, ranging from 20% to 50%. The causes of infertility in women with endometriosis mainly involve anatomical distortions, endocrine abnormalities, and immune disorders (Taylor et al., 2021; Tanbo and Fedorcsak, 2017; Bonavina and Taylor, 2022). Implantation of the embryo depends on the endometrial inflammatory mechanism during pregnancy; endometriosis creates opportunities for chronic inflammation and disrupts endometrial receptivity, leading to infertility (Lessey and Kim, 2017).

Infertility is one of the most common problems among couples worldwide (Shaulov et al., 2020). The study found that implantation rate, clinical pregnancy rate, and ovarian response were lower in patients with endometriosis than in patients with tubal infertility (Zhong et al., 2021; Coccia et al., 2011; Al-Azemi et al., 2000; Boucret et al., 2020). Infertile patients with endometriosis impacted endometrial receptivity and endometrium decidualization (Kim et al., 2019). Human endometrium has a crucial role in the implantation process (Ranisavljevic et al., 2019). Endometrial deindividuation is regulated by the synergistic action of maternal steroid hormones, estrogen, and progesterone and is a necessary prerequisite for embryo implantation in early pregnancy. Uterine stromal cell mitosis plays a vital role in this process, and stromal cells must undergo mitotic expansion before full decidualization (Wang et al., 2010; Muter et al., 2015).

Endometriosis-associated infertility arises from the complex interplay of multiple mechanisms, including compromised oocyte quality, disrupted embryonic development, ovarian dysfunction, and diminished endometrial receptivity (Bonavina and Taylor, 2022). The WNT4/WNT5A genes, which serve as pivotal regulators in embryo implantation and uterine development, exhibit abnormal expression patterns that are closely linked to endometriosis. The WNT signaling pathway plays a critical role in the initiation and progression of endometriotic lesions by modulating cell proliferation, differentiation, and tissue remodeling processes (Gaetje et al., 2007; Sanchez et al., 2014). Current treatment strategies for endometriosis-related infertility have evolved beyond traditional lesion excision to encompass targeted therapies addressing the underlying pathogenic mechanisms. Recent studies emphasize the significance of regulating the hormonal milieu, attenuating inflammatory responses, and improving endometrial receptivity. Several novel pharmacological agents, such as letrozole, GnRH modulators, and progestogen-based drugs, demonstrate substantial therapeutic potential in clinical practice (Colombi et al., 2024). Furthermore, endometriosis exhibits a strong genetic predisposition and familial clustering tendency (McGrath et al., 2023).

Despite much evidence showing relationships between endometriosis and infertility, the mechanisms implicated in endometriosis-associated infertility are so far not fully understood. Transcriptomic methods ranging from large-scale RNA sequencing to single-cell/space technologies have become indispensable approaches in reproductive biology, including ovarian development, reproductive tract development, embryonic development, stem cell differentiation, and tissue regeneration (Gulati et al., 2025). They can help to analyze gene regulatory networks, accelerate the discovery of biomarkers for endometriosis, and reveal conserved pathways among plants, insects, and mammals (Li et al., 2024; Marečková et al., 2024). Therefore, screening differentially expressed genes between endometriosis and infertility may provide a new way to identify the pathogenesis of infertile endometriosis and give a new direction for treatment.

Endometriosis is a chronic disease influenced by environmental and genetic factors, which has a high socioeconomic impact. The infertile endometriosis has apparent characteristics of reduced decidualization and impaired uterine receptivity. Endometrial receptivity depends on the precise and coordinated proliferation, differentiation, and apoptosis processes of endometrial stromal cells and glandular epithelial cells within the “implantation window” (6–10 days after ovulation) (Yang et al., 2022). This process is strictly regulated by Cyclins and cyclin-dependent kinases (CDKs). During the estrogen-dominated proliferative phase, the Cyclin D-CDK4/6 complex is required to drive cells from the G1 phase to the S phase (DNA replication), providing a basis for intimal thickening. If this stage is dysregulated (such as overexpression of Cyclin D), it may lead to excessive endometrial hyperplasia or endometriosis, and damage the receptivity of the endometrium. The secretory phase induced by progesterone relies on the Cyclin B-CDK1 complex to initiate mitosis, promote decidualization of intimal stromal cells, and differentiate them into glycogen-rich secretory cells, creating conditions for embryo adhesion. If inflammation or hormonal disorders lead to the inhibition of CDK1 activity, decidualization will be blocked and the receptivity of the endometrium will decline (Yusuf et al., 2023). Endometrial decidualization was the essential process to prepare the endometrium for pregnancy. Women with endometriosis are at increased risk of infertility by impacting the endometrial decidualization process (Giudice and Kao, 2004). Uterine stromal cell mitosis plays an essential role in this process and must undergo mitotic expansion before full decidualization (Wang et al., 2010; Muter et al., 2015). This study takes advantage of the similarity between endometriosis and infertility in mitosis to find a target for infertility treatment.

Based on the analysis of three data sets, GSE7305, GSE7307, and GSE51981, a PPI network was constructed in the GEO database, and DEGs screening were performed on the three data sets. We obtained 93 DGEs by taking the intersection of three endometriosis datasets. Then, we identified 11 potential mitosis-related downregulated hub genes, among which eight genes (KIF4A, BUB1B, NEK2, FBXO5, KIF11, CENPE, CCNA2, and NCAPG) showed good diagnostic properties of endometriosis and two genes (CCNA2, CENPE) were closely related to infertile endometriosis. The main enriched GO functions revealed that the cell cycle mitotic pathway may be the critical pathway in endometriosis. It has been reported that assessing mitosis rates provides additional diagnostic value for advanced endometriosis (Wetzk et al., 2022), which hints at the accuracy of the signaling pathway we predict.

There is significant evidence that eight hub genes related to mitosis play a crucial role in endometriosis or fertility.

It is reported that KIF4A is a member of the kinase protein superfamily and is involved in a series of cellular processes, such as chromosome aggregation and cytoplasmic division during mitosis. KIF4A may regulate the meiosis of mouse oocytes by affecting the precise separation of spindle tissue and chromosomes, and the loss of KIF4A may be related to aneuploidy of aging oocytes (Tang et al., 2018). KIF4A can bind to BUB1 to regulate the expression of BUB1. BUB1B is an oocyte-expressed growth factor essential for follicular development. Endometriosis harms granular cells, and MnBP concentrations are associated with endometriosis. MnBP may affect the function of granulocyte cells by altering the expressions of BUB1B, CDC20, and cyclin B1 genes (Jin and Ye, 2021; Chou et al., 2020; Racki and Richter, 2006). NEK2 is a protein that is crucial in regulating various cell cycle processes. Its overproduction can disrupt the natural development of male germ cells, leading to abnormalities (Rhee and Wolgemuth, 2002). FBXO5 has been identified as a genuine substrate of beta-Trcp1. It has been observed that beta-Trcp1 plays a vital role in regulating the proper sequence of meiotic and mitotic events. KIF11 is a type of kinesin composed of four identical subunits, and its protein expression is at its highest level during mitosis. If the recruitment of KIF11 on meiotic spindles is reduced, it could impair the proper functioning of these spindles (Guardavaccaro et al., 2003; Dong et al., 2023). CENPE is expressed during mitosis and plays critical roles in inaccurate chromosome alignment and as an emerging target for chemotherapy in clinical oncology (El-Arabey et al., 2018). The protein CCNA2 plays a crucial role in regulating the cell cycle progression, specifically in promoting cell proliferation. It is an indispensable component for the development of embryos (Chotiner et al., 2019). NCAPG is a critical component of condensin I, a protein complex that helps compact DNA during cell division. Its role in chromatin condensation during mitosis is well established. Recent studies have shown that NCAPG is also closely linked to fertility traits in Japanese Black cattle (Kawaguchi et al., 2020).

Co-expressed and miRNAs were chosen to construct mRNA-miRNA interaction networks to identify the critical miRNAs for the prognosis of endometriosis. As Figure 4 shows, BUB1B had 32 miRNAs, CCNA2 had 115 miRNAs, CENPE had 35 miRNAs, FBXO5 had 56 miRNAs, KIF11 had 61 miRNAs, KIF4A had 34 miRNAs, NCAPG had 61 miRNAs, NEK2 had 26 miRNAs. Endometriosis and fertility have been found to have links with multiple miRNAs. Numerous studies have reported on the association of miRNAs with these conditions. For example, Hsa-let-7i-5p, hsa-mir-125b-4p, and hsa-mir-29a-3p could be potential biomarkers and therapeutic targets for diagnosing and treating endometriosis (Gu et al., 2020; Vanhie et al., 2019). Moreover, miR-124-3p significantly regulates cell proliferation and invasion of ectopic endometrium through multiple pathways (Liu et al., 2019; Liu et al., 2023; Yuan et al., 2022). What is more, Hsa-mir-22-3p is not only an essential gene in granulosa cells of patients with biochemical primary ovarian insufficiency, which is a common condition leading to the pathological decline of ovarian function in women of reproductive age, resulting in infertility, but also a sensitive and specific indicator in distinguishing endometriosis from non-endometriosis (Liu et al., 2024; Nazri et al., 2023).

Although all eight screened MRHGs have been reported to mediate mitosis, it should be noted that there is a lack of evidence regarding their ability to regulate mitosis in endometriosis, especially in infertile endometriosis. Moreover, the sample size of infertile patients with endometriosis is limited, and more comprehensive investigations are necessary to analyze the underlying mechanisms in the future.

Our study has identified eight potential mitosis hub genes (KIF4A, BUB1B, NEK2, FBXO5, KIF11, CENPE, CCNA2, and NCAPG) that exhibit excellent diagnostic properties for endometriosis. We have also constructed a network of associated mRNA-miRNA pathways. In addition, we have found that two of these hub genes (MRHGs) are related to infertile endometriosis and have shown high drug-targeting relevance for cordycepin. These findings provide new insights into the unique relationship between mitosis and endometriosis. However, they lack clinical certification. In future work, we will make full use of clinical samples for confirmation as much as possible.

Although the limited sample size is a challenge, our study provides a solid foundation for further research in the field of cross-cutting endometriosis and infertility. By addressing this limitation through collaborative efforts, validation studies, and integrating various data types, we can improve our understanding of the pathogenesis in which endometriosis damages female fertility and pave the way for improved diagnosis and targeted treatment of this condition.