Prostaglandin F2 α (PGF2 α) is a key factor in the triggering of the regression of the corpus luteum (CL). Furthermore, it has been reported that Slit/Robo signaling is involved in the regulation of luteolysis. However, the interactions between PGF2 α and Slit/Robo in the progression of luteolysis remain to be established. This study was designed to determine whether luteolysis is regulated by the interactions of PGF2 α and Slit/Robo in the mouse CL. Real-time PCR and immunohistochemistry results showed that Slit2 and its receptor Robo1 are highly and specifically co-expressed in the mouse CL. Functional studies showed that Slit/Robo participates in mouse luteolysis by enhancing cell apoptosis and upregulating caspase3 expression. Both in vitro and in vivo studies showed that PGF2 α significantly increases the expression of Slit2 and Robo1 during luteolysis through protein kinase C-dependent ERK1/2 and P38 MAPK signaling pathways, whereas an inhibitor of Slit/Robo signaling significantly decreases the stimulating effect of PGF2 α on luteolysis. These findings indicate that Slit/Robo signaling plays important roles in PGF2 α-induced luteolysis by mediating the PGF2 α signaling pathway in the CL.
XueJing Zhang, JianHua Li, JiaLi Liu, HaoShu Luo, KeMian Gou and Sheng Cui
Li Zhang, XiaoXin Zhang, Xuejing Zhang, Yu Lu, Lei Li and Sheng Cui
MicroRNAs (MiRNAs) play important regulatory roles in many cellular processes. MiR-143 is highly enriched in the mouse ovary, but its roles and underlying mechanisms are not well understood. In the current study, we show that miR-143 is located in granulosa cells of primary, secondary and antral follicles. To explore the specific functions of miR-143, we transfected miR-143 inhibitor into primary cultured granulosa cells to study the loss of function of miR-143 and the results showed that miR-143 silencing significantly increased estradiol production and steroidogenesis-related gene expression. Moreover, our in vivo and in vitro studies showed that follicular stimulating hormone (FSH) significantly decreased miR-143 expression. This function of miR-143 is accomplished by its binding to the 3’-UTR of KRAS mRNA. Furthermore, our results demonstrated that miR-143 acts as a negative regulating molecule mediating the signaling pathway of FSH and affecting estradiol production by targeting KRAS. MiR-143 also negatively acts in regulating granulosa cells proliferation and cell cycle-related genes expression. These findings indicate that miR-143 plays vital roles in FSH-induced estradiol production and granulosa cell proliferation, providing a novel mechanism that involves miRNA in regulating granulosa cell functions.
Xin Li, Hongjiao Li, Di Zhang, Guojin Xu, Jinglin Zhang and Sheng Cui
MicroRNA-7 (miR-7) is an important modulator of a plenty of gene expressions and the interrelated biological processes, highly expressed in porcine pituitary. Norepinephrine (NE), acting as an important neurotransmitter or/and a hormone secreted excessively under stress, affects the synthesis and secretion of various hormones, including pituitary follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which are the key hormones which regulate sexual maturation and reproductive functions. However, the relationship among NE, miR-7 and gonadotropin needs to be elucidated. The aim of this study was to identify whether miR-7 involved in the NE-adrenoceptor signaling pathway affects the synthesis and secretion of FSH and LH in porcine pituitary. Our results showed that the NE intracerebroventricular injection increased pituitary miR-7 level and the synthesis and secretion of FSH and LH in porcine, whereas the inhibition of either endogenous miR-7 or β-adrenergic receptors hindered the rise of FSH and LH synthesis induced by NE in cultured primary porcine anterior pituitary cells. Further, we identified the molecular type of β-adrenergic receptors and the signaling pathway in porcine pituitary, and we found that NE played its roles relying on adrenoceptor beta 2 (β2AR) and the RAF/MEK/ERK1/2 signaling pathway. The phosphorylation of ERK1/2 upregulated miR-7 level which subsequently enhanced FSH and LH synthesis by targeting to Golgi glycoprotein 1 (GLG1). These suggest that miR-7 mediates NE’s effect on promoting FSH and LH synthesis in porcine pituitary.