Abstract

As a member of the MicroRNA s (miRNAs) family, miR-421 has been widely studied in regulating the proliferation and apoptosis of cancer cells a. However, there are still no reports on miR-421 in regulating adipocyte differentiation and its related mechanisms. Accordingly, this study aimed to investigate the potential involvement of miR-421 in goat intramuscular preadipocytes (P_IMA). The expression level of miR-421 was measured via quantitative real-time PCR during goat P_IMA differentiation. And the effects of miR-421 on goat P_IMA differentiation were studied by liposome transfection, Oil red O staining and qRT-PCR. Furthermore, the miR-421 target was searched and the underlying mechanism was clarified by luciferase reporter assay and rescue experiment. Our results showed that inhibition of miR-421 could accumulation of lipid droplets by upregulation the expression level of AP2, LPL, C/EBPα and SREBP1. Further studies showed that fibroblast growth factor 13 (FGF13) was the direct target of miR-421. Knocking down of FGF13 expression could inhibit lipid droplet formation and down-regulated the expression of key adipogenic regulatory genes. In addition, the rescue experiment revealed that FGF13 is involved in miR-421-induced differentiation of goat P_IMA as a key factor. Overall, these findings indicate that miR-421 is a negative regulator in the progression of differentiation of goat P_IMA by inhibiting the expression of FGF13.

摘要

作为微小RNA（miRNA）家族的一员，miR-421在调控癌细胞增殖和凋亡方面已被广泛研究。但目前尚无关于miR-421调控脂肪细胞分化及其相关机制的报道。因此，本研究旨在研究 miR-421 在山羊肌内前脂肪细胞 (P_IMA) 中的潜在参与。在山羊 P_IMA 分化过程中通过定量实时 PCR 测量 miR-421 的表达水平。并通过脂质体转染、油红O染色和qRT-PCR研究了miR-421对山羊P_IMA分化的影响。此外，还搜索了 miR-421 靶标，并通过荧光素酶报告基因测定和拯救实验阐明了潜在机制。AP 2、LPL、C/EBPα和SREBP1。进一步的研究表明，成纤维细胞生长因子13 ( FGF13 ) 是 miR-421 的直接靶标。敲低FGF13表达可以抑制脂滴形成并下调关键脂肪形成调节基因的表达。此外，拯救实验表明，FGF13作为关键因素参与 miR-421 诱导的山羊 P_IMA 分化。总的来说，这些发现表明 miR-421 通过抑制FGF13的表达在山羊 P_IMA 的分化进程中起到负调节作用。