[Co-culture with umbilical cord mesenchymal stem cells promotes the synthesis and mechnism of milk protein in bovine mammary epithelial cells].

OBJECTIVE

To explore the possible mechanism of umbilical cord mesenchymal stem cels( UCMSCs) regulating milk protein synthesis in bovine mammary gland epithelial cells( BMECs).

METHODS

UCMSCs and BMECs were co-cultured by double-chamber TranswellTM,and other BMECs were cultured alone as a control group. Insulin like growth factor 1 receptor( IGF-1R) inhibitor AG1024 was used to treat cells. IGF-1,β casein( CSN2) and κ casein( CSN3) content in the supernatants were determined by ELISA; the relative expression abundance of Janus kinase and signal transducer and activator of transcription factor( JAK / STAT) signaling pathway-related genes were detected by quantitative real-time PCR( qRT-PCR); and after the cells were treated with JAK2 signal blocker AG490,qRT-PCR was performed to test the relative expression abundance of CSN2 and CSN3 mRNAs.

RESULTS

CSN2, CSN3 synthetic quantity, and the relative expression abundance of CSN2,CSN3,JAK2,STAT5,E74-like ETS transcription factor 5( ELF5) mRNAs of the co-culture group were significantly higher than those of the control group. After treated with AG1024,the co-culture group showed remarkably decreased CSN2,CSN3 synthesis in BMECs as wel as the decreased relative expression abundance of CSN2,CSN3,JAK2,STAT5,ELF5 mRNAs. After blocked with AG490,the relative expression abundance of CSN2 and CSN3 mRNAs were reduced significantly in the co-culture group. In addition,the expressions of CSN2 and CSN3 mRNAs were inhibited significantly when both AG1024 and AG490 were supplemented.

CONCLUSION

UCMSCs can mediate JAK2 / STAT5 signaling pathwayvia IGF-1,and increase the expressions of milk protein synthesis key genes in BMECs,thus promoteing the synthesis of milk protein.