Regulation Of MiR-142-3p To Gene Prlr Expression In Mouse Mammary Gland Development And Lactation

MiRNA was a new star in lift science research in recent years. MiRNAs play wide roles in many biologicalprocesses such as development,differention,cell proliferation,and apoptosis.With the discovery and the deep functionresearch on the miRNA, the research of mammary gland development and laction regulation also entered a new levelof miRNA regulation. miR-142-3p have different functions in many kinds of cells. We use microarray detected theexpression of miR-142-3p in different development stages mammary tissue are marked different. But the mechanismsof miR-142-3p regulate mouse mammary gland development and lactation was not known.Prolactin（PRL）was an important class of hormones which widely expressed in higher animals. PRL play animportant role in the regulation of animal mammary gland development and lactation. PRL combined with PRLR,trigger the JAK2/STAT5signal pathway, eventually activate the trans-acting factors STAT5signal into the cell, affectthe expression of milk protein gene promoter. Activated or enhanced the geng regulated by protein gene promoter. Thesynergy of a variety of hormones and cytokines co-regulated mammary gland development, prolactin and thedegradation process. Prolactin and prolactin receptor were in the hormones and cytokines. So PRLR have animportant regulatory role in mouse mammary gland development and lactation process. The expression of PRLR wastight related to the mouse mammary gland development, lactation and quality of milk.Akt is a member of serine/threonine protein kinase superfamily, play a role in cell survival, proliferation,metabolism and apoptosis. Akt is in the central position of the Akt/mTOR signal transduction pathway. As oneimportant of the Akt substrates, TOR could integrat growth factor and nutrient signal. TOR’s upstream stimulatingfactor through a different cell surface receptor or a target protein, the signal transduction to the mTOR and regulatedcell growth and proliferation. mTOR pathway play an important role in the metabolism and growth of mammaryepithelial cells, the study results suggest that nutrients and hormonal regulation of milk protein synthesis via themTOR pathway. Sterol regulatory element binding protein (SREBP) belongs to the family of nuclear transcriptionfactor. It is an important transcriptional regulator of fat synthesis genes factor. SREBP high expression can lead to ahigh fat synthesis enzyme gene expression. The study found that, SREBP may be the main regulator about mammaryfatty acid synthesis. Breast milk in the formation of the fatty acid chain, desaturation, an extension of the fatty acidchain, as well as the process of fat synthesis upregulation of activity changes may be related to increased activity ofSREBP-1. Furthermore, SREBP-1in the mammary gland development and lactation process having multipleregulations. GLUT1glucose transport systeme constitute the mouse, rat and bovine mammary epithelial cells, located in the plasma membrane of most cells. GLUT1is responsible for the basal level of glucose absorption, and is closelyrelated to energy metabolism.In this study, use mouse mammary epithelial cells（MMECs）as cell model in vitro. Transfected miR-142-3pmimics/inhibitor with liposomal transfection method. Using real-time quantitative PCR detects PRLR and its cascadpathways genes in mouse MMECs. using Western blotting deceted the expression changes of PRLR signalingmolecules. By the CASY cell viability analyzer to detect the number changes of living cells and cell viability. HPLCdetect the changes in beta-casein secretion. At the same time the application the TG kit to detect cells triglyceridesecretion. In order to explore the mechanism of prolactin regulation on mammary gland. The experiment resultsshowed that:①Real-time quantitative PCR results consistently with the chip showed results. miR-142-3p expressed invarious periods of the mouse mammary. Compared to pregnancy, lactation and degradation period, the expression ofmiR-142-3p was highest in virgin. There was a significant difference., miR-142-3p was the lowest expression inlactation. The results suggests that miR-142-3p could regulation the cyclical changes of the mouse mammary glanddevelopment and lactation.②CASY detected the numbers and viability changes of MMECs. HPLC measured the secretion changes ofbeta-casein. The results showed that miR-142-3p inhibited cell viability and proliferation,and inhibited the secretoryability of the epithelial cells secreted the beta-casein. TG kit test results showed that miR-142-3p significantly inhibitedmouse mammary epithelial cells secrete triglyceride. HPLC measured the secretion changes of lactose, the resultsshowed that miR-142-3p didn’t effect the secretion of lactose significantly.③Quantitative PCR and Western Blotting test results showed that miR-142-3p inhibited endogenous PRLRmRNA and protein expression.Impact the PRLR-related lactation signaling molecules. The expression of SREBP,AKT, mTOR, STAT5was decreased after overexpress miR-142-3p. The expression of lactating signaling moleculesSREBP, AKT mTOR, STAT5increased after miR-142-3p expression reduced. The results suggest that miR-142-3pregulation through the regulation and control the the expression of PRLR, by step regulate the milk protein andbutterfat regulation related lactation signaling molecules. According to the results, we speculate, miR-142-3p byregulating the expression of PRLR, impact associated with milk protein and butterfat signaling pathway geneexpression, but no effect on the metabolism of lactose.The exact regulation mechanism of miR-142-3p should befurther carried out.④ThisstudyexaminedtheexpressionofGLUT1inMMECs,eitheroverexpressionorinhibittheexpressionofmiR-142-3p GLUT1were increased. miR-142-3p has little effect on the expression of GLUT1.