miR-99a-5p inhibits target gene FZD5 expression and steroid hormone secretion from goat ovarian granulosa cells

Abstract

MicroRNA (miRNA) has vital regulatory effects on the proliferation, differentiation and secretion of ovarian granulosa cells, but the role of miR-99a-5p in goat ovarian granulosa cells (GCs) is unclear. Both miR-99a-5p and Frizzled-5 (FZD5) were found to be expressed in GCs in goat ovaries via fluorescence in situ hybridization and immunohistochemistry, respectively, and FZD5 was verified (P<0.001) as a target gene of miR-99a-5p by double luciferase reporter gene experiments. Furthermore, FZD5 mRNA and protein expression were both found to be regulated (P<0.05) by miR-99a-5p in GCs. Moreover, the overexpression of miR-99a-5p or knockdown of FZD5 suppressed (P<0.05) estradiol and progesterone secretion from the GCs, as determined by ELISA. In summary, miR-99a-5p inhibits target gene FZD5 expression and estradiol and progesterone synthesis in GCs. Our study thus provides seminal data and new insights into the regulatory mechanisms of follicular development in the goat and other animals.

Keywords

• miRNA
• Frizzled-5
• follicular development
• estradiol, progesterone