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 transduction genes of mammary gland epithelial cells, including prlr, erα, akt1, socs2, pparγ and elf5, will be helpful to reveal the molecular mechanism. Western blot and qRT- PCR were used to study the change of prlr, erα, akt, socs2, pparγ, and elf5 expression at mRNA and protein level. Co- localization expression of prolactin receptor （PRLR） and estrogen receptor α （ERα） was observed by immunofluorescence; the expression changes of miRNAs （21, 125b, 143, and 195） and the secretion of β-casein and lactose were detected by qRT-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 pparγ expressions. DBP promoted socs2 mRNA expression, but its protein expressions were 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.

Metabolic Regulation of Mammary Gland Epithelial Cells of Dairy Cow by Galactopoietic Compound Isolated from Vaccariae segetalis

In previous experiment, we isolated a compound dibutyl phthalate （DBP） from Vaccaria segetalis which had galactopoietic function on mammary gland epithelial cells of dairy cow （DCMECs）. In this experiment, we ascertained the metabolic regulation function of DBP on DCMECs. Many genes related to lactation including Stat5, AMPK, b-casein, Glut1, SREBP-1, PEPCK, and ACC were detected by real-time PCR. Furthermore, Stat5 and AMPK were detected by Western blot and immunofluorescence co-localization, respectively. The results showed that DBP stimulates the expression of Stat5 and p-Stat5, thus activates Stat5 cell signal transduction pathway and stimulates b-casein synthesis. DBP also raises the activities of Glut1 and AMPK to stimulate glucose uptake and glycometabolism and activates the expression of AMPK downstream target genes PEPCK and ACC and expression of SREBP-1 to stimulate milk fat synthesis. In addition, the activities of HK, G-6-PDH, ICDH, ATPase, and energy charges were stimulated by DBP to increase the energy metabolism level of DCMECs. The results showed DBP stimulates energy metabolism related to galactopoietic function in DCMECs.

Construction of Antibacterial Peptide CecropinB Eukaryotic Recombinant Vector and Its Expression in Dairy Goat Mammary Gland Epithelial Cells

To investigate the expression of antibacterial peptide CecropinB cDNA in dairy goat mammary gland epithelial cells,the CecropinB gene was cloned and was inserted into a eukaryotic vector pECFP-C1 to construct the recombinant plasmid pECFP-B by genetic engineering technique.Recombinant plasmid pECFP-B was transfected into dairy goat mammary gland epithelial to detect the bactericidal activity of CecropinB.The expression of CecropinB was also detected.The result of RT-PCR demonstrated CecropinB gene was expressed in transfected cells.CecropinB recombinant plasmid DNA was injected into udders and CecropinB was expressed in mammary gland,exhibiting bactericidal activity to Staphylococcus aureus in vivo experiments.

Effect of Different Concentrations of Lipopolysaccharide on Expression of NF-κB and LAP in Mammary Epithelial Cells of Dairy Cow

The paper was to study the effects of different concentrations of lipopelysaccharide （LPS） on expression of nuclear factor Kappa B （NF-κB） and lingual antimicrobial peptide （LAP） gene in mammary epithelial ceils of dairy cow. The mammary epithelial ceils of dairy cow were stimulated by different concentrations （50, 100,200,400 and 800 ng/mL） of LPS. The total RNA of cells was extracted after stimulation for 2, 4, 8, 16, 24, 48 and 72 h, respectively, and the mRNA expression levels of NF-κB P65 and LAP were evaluated by real-time quantitative PCR. The results showed that the expression of NF-κB P65 and LAP mRNA treated with 400 ng/mL LPS for 72 h were the highest compared to the control group （ P 〈0.01 ）. The result confirmed that the expression activity of NF-κB was enhanced in inflammatory effects of inammary epithelial cells induced by LPS, which regulated the expression of defense gene LAP, with certain dose and time effects.

Galactopoietic Activity of Dibutyl Phthalate Isolated from Vaccaria segetalis

A galactopoietic compound, identified as dibutyl phthalate（DBP）, was isolated from Vaccaria segetalis. The activity of DBP on lactation ability of dairy cow mammary gland epithelial cells（DCMECs） cultured in vitro and dairy cow was evaluated. Results showed that DBP could promote cell viability, proliferation ability, lactose and β-casein secretion of DCMECs, which could also raise the milk yields of dairy cows significantly.

3' Noncoding Region Construction of GHR Gene-luciferase Report Vector and Valuation

To analyze miR-139 target sites in 3＇ UTR of GHR gene in dairy cow mammary gland, a GHR 3＇ UTR- luciferase reporter vector was constructed and the effect of miRNA on its activity was evaluated in dairy cow mammary gland epithelial cells （DCMECs）. The miR-139 targeting GHR 3＇ UTR was predicted by Target Scan 5.1 software, 3＇ UTR fragment of GHR was amplified by PCR from RNA of DCMECs. PCR products were cloned into Spe Ⅰ/Hind Ⅱ modified pMIR-Report vector. The luciferase reporter vector and miRNA eukaryotic expression vector were transferred into DCMECs using lipofectamine 2000 transfection reagent. The dualluciferase reporter assay system was used to quantitiate the reporter activity. The results showed that a 107 bp 3＇ UTR fragment of GHR gene was successfully cloned into the pMIR-Report vector, which authenticated by Spe Ⅰ/Hind Ⅲ digestion and DNA sequencing. The luciferase activity of reporter construction treated with miR-139 decreased 20.87% compared with the control group. It was concluded that the GHR3＇ UTR-luciferase reporter vector had been successfully constructed. The luciferase activity of the reporter could be suppressed by miR- 139.