MiR-29c-5p regulates the function of buffalo granulosa cells to induce follicular atresia by targeting INHBA

IGF2BP3 curbed by miR-15c-3p restores disrupted lipid storage and progesterone secretion in chicken granulosa cells under oxidative stress through AKT-Raf1-ERK1/2 signaling pathway

For commercial laying hens, the continuous high-intensity ovulation process leads to a significant accumulation of reactive oxygen species (ROS) in the granulosa cells, inducing oxidative stress, which accelerates ovarian aging and shortens the peak laying period. The molecular mechanisms underlying this process remain poorly understood. Therefore, we modeled the processes of oxidative stress and antioxidant in chicken granulosa cells. Small RNA sequencing revealed that miR-15c-3p expression was elevated by oxidative stress induction and attenuated by antioxidant curcumin. Functional validation with miR-15c-3p mimic and inhibitor confirmed the role of miR-15c-3p in exacerbating oxidative stress and resultant suppression of lipid droplet storage and progesterone secretion in chicken granulosa cells by targeting insulin-like growth factor 2 binding protein 3 (IGF2BP3). These regulatory effects were mediated through the sequential downstream signaling cascade of AKT-Raf1-ERK1/2. In conclusion, IGF2BP3 curbed by miR-15c-3p restores disrupted lipid storage and progesterone secretion in chicken granulosa cells under oxidative stress through AKT-Raf1-ERK1/2 signaling pathway. These findings offer new insights into the molecular mechanisms by which oxidative stress damages reproductive capacity and a theoretical basis for mitigating oxidative stress in laying hens through genetic improvement.

miR-24-3p inhibits lipid synthesis and progesterone secretion in chicken granulosa cells via ERK1/2 signaling pathway

Normal follicular development is the basis for ovulation in poultry. Our previous sequencing analysis revealed a high expression of miR-24-3p in chicken follicles from degenerated ovaries, suggesting that miR-24-3p may modulate follicular development. Hence, this study investigated the specific mechanisms of miR-24-3p in regulating chicken follicular development. The results revealed that the proliferation, lipid synthesis, and progesterone secretion were significantly inhibited after miR-24-3p overexpression in chicken granulosa cells, vice versa by miR-24-3p knockdown. Dual-specificity phosphatase 16 (DUSP16) and thousand and one amino acid kinase 1 (TAOK1) were identified as potential target genes of miR-24-3p. Further validation revealed that knockdown of DUSP16 and TAOK1 suppressed proliferation, lipid synthesis, and progesterone secretion in chicken granulosa cells. Moreover, we observed that miR-24-3p, along with knockdown of DUSP16 and TAOK1, increased the phosphorylation levels of extracellular signal-regulated kinases 1 and 2 (ERK1/2). Our previous study proved that activation of ERK1/2 inhibited lipid synthesis and progesterone secretion of chicken granulosa cells. In summary, we demonstrated that miR-24-3p targeting DUSP16 and TAOK1 disrupts lipid synthesis and progesterone secretion via ERK1/2 signaling pathway in chicken granulosa cells in vitro. These results may provide a new theoretical basis for resolving miRNAs regulation on reproductive performance of chickens.

Circular RNA circRPS19 promotes chicken granulosa cell proliferation and steroid hormone synthesis by interrupting the miR-218-5p/INHBB axis

Ovarian follicle development is an important physiological activity for females and makes great significance in maintaining female health and reproduction performance. The development of ovarian follicle is mainly affected by the granulosa cells (GCs), whose growth is regulated by a variety of factors. Here, we identified a novel circular RNA (circRNA) derived from the Ribosomal protein S19 (RPS19) gene, named circRPS19, which is differentially expressed during chicken ovarian follicle development. Further explorations identified that circRPS19 promotes GCs proliferation and steroid hormone synthesis. Furthermore, circRPS19 was found to target and regulate miR-218-5p through a competitive manner with endogenous RNA (ceRNA). Functionals investigation revealed that miR-218-5p attenuates GCs proliferation and steroidogenesis, which is opposite to that of circRPS19. In addition, we also confirmed that circRPS19 upregulates the expression of Inhibin beta B subunit (INHBB) by binding with miR-218-5p to facilitate GCs proliferation and steroidogenesis. Overall, this study revealed that circRPS19 regulates GCs development by releasing the repression of miR-218-5p on INHBB, which suggests a novel mechanism in respect to circRNA and miRNA regulation in ovarian follicle development.