Granulosa cells (GCs) proliferation and estradiol synthesis significantly affect follicular development. The miR-214-3p expression in the ovarian tissues of high-yielding sows is higher than that in low-yielding sows, indicating that miR-214-3p may be involved in sow fertility. However, the functions and mechanisms of miR-214-3p on GCs are unclear. This study focuses on miR-214-3p in terms of the effects on GCs proliferation and estradiol synthesis. Our findings revealed that miR-214-3p promotes proliferation and inhibits estradiol synthesis in porcine GCs. MiR-214-3p can increase the percentage of S-phase cells, the number of EdU labeled positive cells, and cell viability. However, E2 concentration was reduced after miR-214-3p agomir treatment. We also found that miR-214-3p up-regulates the expression of cell cycle genes including cell cycle protein B (Cyclin B), cell cycle protein D (Cyclin D), cell cycle protein E (Cyclin E), and cyclin-dependent kinase 4 (CDK4) at the transcription and translation levels, but down-regulates the mRNA and protein levels of cytochrome P450 family 11 subfamily A member 1 (CYP11A1), cytochrome P450 family 19 subfamily A member 1 (CYP19A1), and steroidogenic acute regulatory protein (StAR) (i.e., the key enzymes in estradiol synthesis). On-line prediction, bioinformatics analysis, a luciferase reporter assay, RT-qPCR, and Western blot results showed that the target genes of miR-214-3p in proliferation and estradiol synthesis are Mfn2 and NR5A1, respectively. Our findings suggest that miR-214-3p plays an important role in the functional regulation of porcine GCs and therefore may be a target gene for regulating follicular development.

中文翻译：

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MiR-214-3p 在猪颗粒细胞中促进增殖并抑制雌二醇合成。

颗粒细胞 (GCs) 增殖和雌二醇合成显着影响卵泡发育。高产母猪卵巢组织中miR-214-3p的表达高于低产母猪，说明miR-214-3p可能与母猪的生育能力有关。然而，miR-214-3p 在 GCs 上的功能和机制尚不清楚。本研究重点关注 miR-214-3p 对 GCs 增殖和雌二醇合成的影响。我们的研究结果表明，miR-214-3p 在猪 GC 中促进增殖并抑制雌二醇合成。MiR-214-3p 可以增加 S 期细胞的百分比、EdU 标记的阳性细胞数量和细胞活力。然而，在 miR-214-3p agomir 处理后，E2 浓度降低。我们还发现miR-214-3p上调细胞周期基因的表达，包括细胞周期蛋白B（Cyclin B）、细胞周期蛋白D（Cyclin D）、细胞周期蛋白E（Cyclin E）和cyclin-dependent激酶 4 (CDK4) 在转录和翻译水平，但下调细胞色素 P450 家族 11 亚家族 A 成员 1 (CYP11A1)、细胞色素 P450 家族 19 亚家族 A 成员 1 (CYP19A1) 和类固醇急性调节的 mRNA 和蛋白质水平蛋白质（StAR）（即雌二醇合成中的关键酶）。在线预测、生物信息学分析、荧光素酶报告基因检测、RT-qPCR和Western blot结果显示，miR-214-3p在增殖和雌二醇合成中的靶基因分别为Mfn2和NR5A1。