Downregulation of SRSF3 promotes ADD3 exon 14 skipping and drives the progression of endometriosis

Abstract Endometriosis (EMs) is a common and complex gynecological disease with an unclear pathogenesis. Splicing factors play critical roles in the progression of various diseases. However, the expression pattern and biological function of serine/arginine-rich splicing factor 3 (SRSF3) in EMs remain incompletely understood. This study aimed to investigate whether the splicing factor SRSF3 participates in the pathogenesis of endometriosis by regulating the alternative splicing of the Adducin 3 (ADD3) gene. Ectopic and eutopic endometrial tissues were collected from patients with EMs, with normal endometrial tissues from non-EMs women serving as controls. The expression levels of SRSF3 and ADD3 were detected by qRT-PCR and Western blot. Overexpression vectors for SRSF3 and two splice isoforms of ADD3 (ADD3(+ 14) and ADD3(− 14)) were constructed and transfected into ectopic endometrial stromal cells (ESCs). Subsequently, the effects on cell proliferation, apoptosis, migration, and invasion were assessed using CCK-8 assay, flow cytometry, wound healing assay, and Transwell assay. The binding of SRSF3 to the precursor mRNA of ADD3 was validated by RNA immunoprecipitation (RIP) assay. The results showed that SRSF3 expression was downregulated while ADD3 expression was upregulated in ectopic endometrial tissues. Overexpression of SRSF3 inhibited the splicing of ADD3 exon 14, leading to reduced expression of both isoforms. Functionally, overexpression of ADD3(− 14) enhanced the proliferation, migration, and invasion abilities of ESCs while inhibiting apoptosis, whereas overexpression of SRSF3 exerted the opposite effects. RIP-qPCR confirmed that SRSF3 could bind to the exon 14 region of the ADD3 precursor mRNA. In conclusion, the downregulation of SRSF3 induces the skipping of ADD3 exon 14, generating the ADD3(− 14) isoform, thereby promoting the progression of endometriosis. These findings provide new insights into the pathogenesis of this disease and suggest a potential therapeutic target.