Down-Regulated miR-21 in Gestational Diabetes Mellitus Placenta Induces PPAR-α to Inhibit Cell Proliferation and Infiltration

Purpose: This study aimed to investigate the role of miR-21 expression in the reduction of placental function in GDM patients. Materials and Methods: qRT-PCR was used to detect the differential expression of miR-21 in the serum of gestational diabetes mellitus (GDM) and normal pregnant women, and to verify the functional target gene PPAR-alpha of miR-21 by double fluorescence experiments. Cellular experiments were performed to verify the effect of PPAR-alpha on cell function. Results: miR-21 is down-regulated in the serum and placenta of GDM patients compared to normal pregnant women. In the case of insulin resistance, miR-21-5p knockdown promoted glucose uptake, but no significant effect was found under physiological condition. Functional studies have shown that reduced PPAR-a expression can restore miR-21 knockdown-mediated cell growth and metastasis inhibition. Additionally, decreased expression of miR21 but increased expression of -PPAR-alpha was observed in patients with GDM and GDM rats. Conclusion: The expression of the placental miR-21-5p, which inhibits cell growth and infiltration by up-regulating PPAR-alpha, is downregulated in pregnant GDM patients, which in turn may affect the placental function.