Influence on Cellular Signal Transduction Pathway in Dairy Cow Mammary Gland Epithelial Cells by Galactopoietic Compound Isolated from Vaccariae segetalis

The galactopoietic mechanism of Vaccaria segetalis is still unknown. Understanding dibutyl phthalate (DBP) separated from Vaccaria segetalis on the expression of lactation signal transduetion genes of mammary gland epithelial cells, including prlr, erα, akt1, socs2, pparγand elf5, will be helpful to reveal the molecular mechanism. Western blot and qRTPCR were used to study the change of prlr, erα, akt, socs2, pparγ, and elf5 expression at mRNA and protein level. Colocalization expression of prolactin receptor (PRLR) and estrogen receptor α (ERα) was observed by immunofluoreseence;the expression changes of miRNAs (21, 125b, 143, and 195) and the secretion of β-casein and lactose were detected byqRT-PCR and RP-HPLC. The results showed that Vaccaria segetalis active compound had similar fuctions as estrogen and/or prolactin (PRL) in dairy cow mammary gland epithelial cells (DCMECs), increased the expressions of prlr, erα, akt1,and elf5 genes, while repressed ppaγ expressions. DBP promoted socs2 mRNA expression, but its protein expressionswere repressed. Furthermore, both DBP and PRL could repress the expressions of miRNA-125b, miRNA-143 and miRNA-195 in DCMECs. DBP could repress the expression of miRNA-21, while the influence of PRL on miRNA-21 was not certain.DBP could promote the lactation ability of DCMECs by regulating the ER and PRLR cellular signal transduction pathway.