CircIDH2 Modulates Porcine Adipogenesis via the miR-193a-5p/RASGRP4 Axis: Implications for ceRNA-Mediated Regulation of Fat Deposition.

Adipose tissue development plays a critical role in determining carcass quality and meat production efficiency in swine; however, the regulatory mechanisms governing fat deposition remain incompletely understood. Circular RNAs (circRNAs), characterized by high stability and resistance to RNase R degradation, have emerged as important epigenetic regulators of livestock traits. This study investigated the regulatory role of circIDH2 in adipogenic differentiation of porcine preadipocytes and the underlying molecular mechanisms. Functional assays revealed that silencing circIDH2 markedly promoted preadipocyte proliferation while inhibiting differentiation and lipid accumulation; conversely, circIDH2 overexpression produced the opposite effects. Mechanistically, circIDH2 acted as a molecular sponge for miR-193a-5p through complementary base pairing, thereby relieving the repression of its target gene RASGRP4, a positive regulator of adipogenesis. Furthermore, this study demonstrated that miR-193a-5p promoted proliferation but suppressed the differentiation of porcine preadipocytes, whereas RASGRP4 inhibited proliferation while promoting adipogenic differentiation. Rescue experiments further confirmed the regulatory relationship among circIDH2, miR-193a-5p, and RASGRP4. In summary, the findings indicated that circIDH2 functioned as a key regulator of adipogenesis by modulating the miR-193a-5p/RASGRP4 axis, thereby suppressing preadipocyte proliferation and promoting adipogenic differentiation. These results provide a theoretical foundation for future investigations into the regulatory mechanisms of adipose tissue development.