Roles of differential expression of miR-543-5p in GH regulation in rat anterior pituitary cells and GH3 cells

Growth hormone (GH) is an important hormone released by the pituitary gland that plays a key role in the growth and development of organisms. In our study, TargetScan analysis and the dual luciferase reporter assays were used to predict and screen for miRNAs that might act on the rat Gh1 gene, and we identified miR-543-5p. Then, the GH3 cell line and the primary rat pituitary cells were transfected with miRNA mimic, inhibitor, and siRNA. We detected the Gh1 gene expression and the GH secretion by real-time PCR and ELISAs, respectively, to verify the regulatory effect of miR-543-5p on GH secretion. The results showed that miR-543-5p can inhibit Gh1 mRNA expression and reduce GH secretion. MiR-543-5p inhibitor upregulated Gh1 mRNA expression and increased GH secretion compared with the negative control. In summary, miR-543-5p downregulates Gh1 expression, resulting in a decrease in GH synthesis and secretion, which demonstrates the important role of miRNAs in regulating GH and animal growth and development.

生长激素（Growth Hormone, GH）是垂体分泌的重要激素，在生物体生长发育进程中发挥核心调控作用。本研究通过TargetScan靶基因预测分析与双荧光素酶报告基因实验，预测并筛选可靶向作用于大鼠Gh1基因的微小RNA（microRNAs, miRNAs），最终鉴定出miR-543-5p。随后，将miRNA模拟物（mimic）、抑制剂（inhibitor）以及小干扰RNA（small interfering RNA, siRNA）转染至GH3细胞系与原代大鼠垂体细胞中。本研究分别采用实时荧光定量PCR（real-time PCR）与酶联免疫吸附实验（ELISA）检测Gh1基因表达水平与GH分泌量，以验证miR-543-5p对GH分泌的调控作用。实验结果表明，miR-543-5p可抑制Gh1 mRNA的表达，并降低GH的分泌量。与阴性对照组相比，miR-543-5p抑制剂可上调Gh1 mRNA的表达水平，并提升GH分泌量。综上，miR-543-5p可下调Gh1基因的表达，进而导致GH合成与分泌水平下降，这一结果证实了miRNAs在调控GH分泌及动物生长发育过程中的重要作用。