CircSTK40 Modulates the SETD1B/H3K4me2/H3K4me3 Loop to Regulate Recurrent Pregnancy Loss.

Area of Science:

• Reproductive Biology
• Epigenetics
• Molecular Genetics

Background:

• Recurrent pregnancy loss (RPL) affects approximately 2.5% of women attempting conception.
• Decidual dysfunction is a key factor in RPL, but its genetic underpinnings are unclear.

Purpose of the Study:

• To investigate the roles of the methyltransferase SETD1B and the circular RNA circSTK40 in the decidual tissue of women with RPL.
• To elucidate the molecular mechanisms by which SETD1B and circSTK40 regulate decidual function and pregnancy maintenance.

Main Methods:

• Comparative analysis of SETD1B and circSTK40 expression in decidual tissue from RPL patients and healthy controls.
• Experimental manipulation of SETD1B and circSTK40 levels in vitro to assess their impact on decidual cell apoptosis, autophagy, and metabolism.
• Investigation of the molecular interactions between circSTK40, SETD1B, and histone H3 using co-immunoprecipitation and chromatin immunoprecipitation assays.

Main Results:

• SETD1B and circSTK40 were significantly downregulated in the decidua of RPL patients.
• SETD1B knockdown impaired decidual function by increasing apoptosis and glycolysis while decreasing autophagy.
• CircSTK40 overexpression rescued these defects, upregulated SETD1B, and promoted H3K4 methylation at the SETD1B promoter, suggesting a positive feedback loop.

Conclusions:

• SETD1B and circSTK40 are critical for maintaining decidual survival and function during pregnancy.
• Their dysregulation contributes to RPL pathogenesis through epigenetic modifications and altered cellular processes.
• Targeting SETD1B and circSTK40 may offer novel therapeutic strategies for RPL.