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This study aimed to evaluate the effect of miR-10b on growth hormone (GH) in pituitary cells of Yanbian yellow cattle. According to analysis of GH and somatostatin receptor 2 (SSTR2) mRNA and protein expression levels, we found that miR-10b targeted 3′UTR of SSTR2. Compared with the negative control (NC) group, GH mRNA transcription and protein expression in pituitary cells of Yanbian yellow cattle were significantly increased by adding miR-10b mimics (p < .01), while these were significantly decreased by adding miR-10b inhibitor (p < .05); compared with the NC group, SSTR2 mRNA transcription and protein expression were significantly inhibited by the addition of miR-10b mimics (p < .01), while these were significantly increased by the addition of miR-10b inhibitor compared with the iNC group (p < .05). This study suggested that miR-10b could regulate GH level by regulating SSTR2 gene expression in pituitary cells of Yanbian yellow cattle.

Yanbian yellow cattle breeding is limited by its slow growth. We previously found that the miRNA miR-6523a is differentially expressed between Yanbian yellow cattle and Han Yan cattle, which differ in growth characteristics. In this study, we evaluated the effects of miR-6523a on growth hormone (GH) secretion in pituitary cells of Yanbian yellow cattle. Bioinformatics analyses using TargetScan and RNAhybrid as well as dual luciferase reporter assays showed that miR-6523a targets the 3' UTR of SSTR5 (somatostatin receptor 5). We further found that the mRNA and protein expression levels of GH in pituitary cells were significantly higher in cells treated with miR-6523a mimic than in the control group (P=0.0082 and P=0.0069). GH mRNA and protein expression levels were lower in cells treated with miR-6523a inhibitor than in the control group, but the difference was not significant (P=0.064 and P=0.089). SSTR5 mRNA and protein levels were inhibited by miR-6523a mimic compared with the control group) (P=0.0024 and P=0.0028) and were elevated slightly by miR-6523a inhibitor (P=0.093 and P=0.091). These results prove that miR-6523a regulates GH secretion in pituitary cells by SSTR5. More broadly, these findings provide a basis for studies of the roles of miRNAs in animal growth and development.

Background There is a relationship between miR-23b-3p and GH in pituitary of Yanbian yellow cattle. However, the specific mechanism of the effect of miR-23b-3p on GH in pituitary of Yanbian yellow cattle is still unclear.This study aimed to evaluate the effect of miR-23b-3p on growth hormone (GH) in pituitary cells of Yanbian yellow cattle.Methods The primary culture of Yanbian yellow cattle pituitary cells was carried out, and mimics (miR-23b-3p-mi group), mimics reference substance (NC group), inhibitor (miR-23b-3p-in group) and inhibitor reference substance (iNC group) of miR-23b-3p were transfected into the established pituitary primary cells. After 48 h, the cells were collected and the total RNA and protein were extracted.The mRNA transcription and protein expression level of GH and miR-23b-3p target genes were detected by real time fluorescence quantitative PCR (qPCR) and Western blot, respectively. The target relationship of miR-23b-3p was validated by double luciferase reporter gene system. ResultsCompared with the NC control group, GH mRNA transcription and protein expression level in pituitary cells of Yanbian yellow cattle was significantly decreased by adding miR-23b-3p minics ( P <0.01), while compared with the iNC control group, GH mRNA transcription and protein expression level were significantly increased by adding miR-23b-3p inhibitor( P <0.05). The result of bioinformatics analysis and double luciferase reporter gene system validation proved that miR-23b-3p targeted 3'UTR of pituitary specific transcription factor 1 (POU1F1). Compared with the NC control group, POU1F1 mRNA transcription and protein expression level were significantly inhibited by the addition of miR-23b-3p minics ( P <0.01), while compared with the iNC control group, POU1F1 mRNA transcription and protein expression level were significantly increased by the addition of miR-23b-3p inhibitor ( P <0.01).Conclusions miR-23b-3p could regulate GH in pituitary cells by regulating POU1F1 gene. BackgroundYanbian yellow cattle are characterized by slow growth rate, long growth cycle, and low market value, leading to prolonged feeding periods and wastage of feed resources, high feeding costs, and consequently negative effects on the Yanbian yellow cattle breeding industry [1][2][3]. Therefore, how to