Dynamic Expression of Follicle-Stimulating Hormone and Estrogen mRNA Receptors Associated with microRNAs and in Canine Follicles during the Estrous Cycle.

The genes encoding for estrogen receptor () and follicle-stimulating hormone receptor () play crucial roles in ovarian follicular development. This study aimed to determine the expression levels of miRNAs predicted against and mRNAs in follicular cells related to their target genes during the estrous cycle in canines. Antral follicles were dissected from 72 ovaries following ovariohysterectomies. MiRNAs regulating and genes were selected from miRNA databases, and mature miRNA and mRNA expression profiling was performed using real-time polymerase chain reaction (PCR). The best miRNA for each target gene was selected considering the quantitative PCR (qPCR) performance and target prediction probability, selecting only miRNAs with a binding -value of 1.0, and choosing and for and , respectively. The expression levels comparing the different phases of the estrous cycle were evaluated using ANOVA. Pearson correlations between the expression pattern of each miRNA and their target genes were performed. Each miRNA and its target genes were expressed in the granulosa cells in all estrous phases. remained low in anestrus and proestrus, increased ( < 0.05) to the highest level in estrus, and decreased ( < 0.05) in diestrus. showed the same trend as , with the highest ( < 0.05) expression in estrus and the lowest ( < 0.05) in anestrus and proestrus. A tendency for an inverse relationship was observed between the expression of and only in the anestrus phase, while an inverse correlation (r = -0.8) was found between and ( < 0.01). The expression profile of and and their predicted target genes of dog ovarian follicles throughout the estrous cycle observed in this study suggest a role in the transcriptional regulation of and , which is the first evidence of the involvement of these miRNAs in the canine follicular function.