CircSSRP1 regulates SMAD3 to affect proliferation and apoptosis of human embryonic palatal mesenchymal cells in nonsyndromic cleft lip with or without cleft palate by sponging miR-708-5p.

OBJECTIVES

Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is a common oral and maxillofacial congenital anomaly with unknown etiology. This study aimed to investigate the potential regulatory role of the circSSRP1/miR-708-5p/SMAD3 axis in NSCL/P.

DESIGN

The circSSRP1/miR-708-5p/SMAD3 axis was predicted via integrated bioinformatics analysis of the GSE42589 and GSE316908 datasets, and its expression was validated in NSCL/P tissues by qRT-PCR. Fluorescence in situ hybridization (FISH) confirmed circSSRP1 subcellular localization. Its effects on proliferation and apoptosis in human embryonic palatal mesenchymal (HEPM) cells were examined in vitro. Dual-luciferase assays, Western blot, and rescue experiments validated molecular interactions.

RESULTS

In NSCL/P tissues, circSSRP1 and SMAD3 were upregulated, while miR-708-5p was downregulated. CircSSRP1 was distributed in both cytoplasm and nucleus. Functionally, overexpression of circSSRP1 or knockdown of miR-708-5p inhibited cell proliferation while promoting apoptosis in HEPM cells. Conversely, knockdown of circSSRP1 or overexpression of miR-708-5p produced the opposite effects. Rescue experiments confirmed that miR-708-5p reversed circSSRP1's effects in HEPM cells. Mechanistically, circSSRP1 sponged miR-708-5p to target SMAD3.

CONCLUSIONS

We identified a novel circRNA, circSSRP1, which inhibits proliferation while promoting apoptosis in HEPM cells by sponging miR-708-5p and modulating SMAD3 expression. Our study reveals the circSSRP1/miR-708-5p/SMAD3 axis as a critical potential in vitro cytological regulatory network implicated in NSCL/P pathogenesis.