Exploring the clinical and cellular mechanisms of LncRNA-KCNQ1OT1/miR-29a-3p/SOCS3 molecular axis in cases of unexplained recurrent spontaneous abortion

Objective: The objective of this study is to explore the functions and mechanisms of the LncRNA-KCNQ1OT1/miR-29a-3p/SOCS3 molecular pathway in the context of unexplained recurrent spontaneous abortion (URSA).

Methods: We conducted qRT-PCR to assess the levels of LncRNA-KCNQ1OT1, miR-29a-3p, and SOCS3 in both abortion tissues from women who experienced URSA and healthy early pregnant women. A dual-luciferase assay was employed to investigate whether miR-29a-3p targets SOCS3. Furthermore, RNA IP and RNA Pull-Down assays were employed to confirm the interaction between KCNQ1OT1 and SOCS3 with miR-29a-3p. RNA FISH was used to determine the cellular localization of KCNQ1OT1. Additionally, trophoblast cells (HTR8/SVneo) were cultured and the CCK-8 assay was utilized to assess cell proliferation, while flow cytometry was employed to analyze cell apoptosis.

Results: Compared to abortion tissues obtained from healthy early pregnant individuals, those from women who experienced URSA displayed a notable downregulation of KCNQ1OT1 and SOCS3, accompanied by an upregulation of miR-29a-3p. Suppression of KCNQ1OT1 resulted in the inhibition of cell proliferation and the facilitation of apoptosis in HTR8/SVneo cells. Our findings suggest that KCNQ1OT1 may exert a regulatory influence on SOCS3 through a competitive binding mechanism with miR-29a-3p. Notably, KCNQ1OT1 exhibited expression in both the cytoplasm and nucleus, with a predominant localization in the cytoplasm. Furthermore, we observed a negative regulatory relationship between miR-29a-3p and SOCS3, as the miR-29a-3p mimic group demonstrated significantly reduced cell proliferation and an increased rate of apoptosis when compared to the negative control (NC mimic) group. Additionally, the SOCS3 Vector group exhibited a substantial improvement in proliferation capability and a marked reduction in the apoptosis rate in comparison to the NC Vector group. The miR-29a-3p mimic + SOCS3 Vector group demonstrated a remarkable enhancement in proliferation and a reduction in apoptosis when compared to the miR-29a-3p mimic group.

Conclusion: The competitive binding of miR-29a-3p to LncRNA-KCNQ1OT1 appears to result in the elevation of SOCS3 expression, consequently fostering the proliferation of trophoblast cells while concomitantly suppressing apoptosis.