MiR-214-3p promotes proliferation and inhibits estradiol synthesis in porcine granulosa cells

Shengjie Shi,Gongshe Yang,Yamei Hu,Xiaoge Zhou,Lutong Zhang,Yankun Li,Guiyan Chu,Jingjing Li

doi:10.1186/s40104-020-00500-y

Abstract

BackgroundGranulosa 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.ResultsOur 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.ConclusionsOur 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.

Highlights

Granulosa cells (GCs), as the largest cell population in mature follicles, are the body’s primary source of estrogen and progesterone
Biological characteristics of miR-214-3p We detected the expression level of miR-214-3p in the ovarian tissue of Yorkshire × Landrace sows with highmiR-214-3p overexpression promotes granulosa cell proliferation In order to determine the effect of miR-214-3p on the proliferation of porcine ovarian GCs, we transfected the GCs samples with miR-214-3p agomir, antagomir, and the negative control
The EdU staining assay showed that the number of EdU labeled positive cells increased in the miR-214-3p agomir group, unlike in the negative control group (Fig. 2d,e)

Summary

Introduction

Granulosa cells (GCs), as the largest cell population in mature follicles, are the body’s primary source of estrogen and progesterone. The morphology and function of GCs are altered by primordial follicle growth initiation, proliferation, differentiation, atresia, ovulation, and luteum formation. GCs can regulate the development of oocytes and follicles by secreting cytokines and hormones, which further affect female reproductive performance [1, 2]. The proliferation and hormone secretion of GCs are closely related to the growth and development of follicles [3]. To this effect, inseparable from GCs proliferation [6]. Granulosa cells (GCs) proliferation and estradiol synthesis significantly affect follicular development. This study focuses on miR-214-3p in terms of the effects on GCs proliferation and estradiol synthesis

Methods

Results

Discussion

Conclusion