CircMYH9/miR-133a-3p/CXCR4 axis: a novel regulatory network in sperm fertilization and embryo development.

This study aimed to investigate the influence of sperm miRNAs on fertilization rates (FR) in in vitro fertilization (IVF) and to explore potential regulatory mechanisms in sperm-mediated fertilization and embryo development. Through high-throughput sequencing, we identified differentially expressed miRNAs in sperm, with miR-133a-3p significantly upregulated in samples associated with low FR and available embryo rate (AER). Key regulatory circRNAs and mRNAs were further identified via the Starbase database, intersected with differentially expressed RNA, and analyzed through GO, KEGG, and PPI analyses. The circMYH9/miR-133a-3p/CXCR4 axis emerged as a critical regulatory network. In vitro assays using the GC-2 spd mouse spermatogenic cell line revealed that miR-133a-3p inhibited cell growth and proliferation while promoting apoptosis. circMYH9, acting as a competing endogenous RNA (ceRNA) for miR-133a-3p, modulated CXCR4 expression, enhancing GC-2 spd cell growth and inhibiting apoptosis through the miR-133a-3p/CXCR4 axis. In vivo experiments using a mouse model confirmed that circMYH9 overexpression increased IVF success rates and promoted embryo development via this axis. Mechanistically, miR-133a-3p suppresses sperm fertilization and embryo development by targeting the circMYH9/miR-133a-3p/CXCR4 axis. These findings suggest that this regulatory network could serve as a novel biomarker for assessing fertilization potential and embryo quality in clinical settings and as a potential therapeutic target to improve IVF outcomes and address infertility. This study provides valuable insights into the molecular mechanisms governing sperm function and early embryonic development.