Assessing cellular agriculture potential: Population homogeneity and gene expression in cultured bovine mammary epithelial cells

Abstract

Mammary epithelial cells (MEC) are responsible for milk synthesis in the bovine mammary gland during lactation, and could thereby potentially be used for in-vitro milk components production. Development of such a model, however, requires the MECs to preserve their lactogenic traits following in-vitro growth. Potential impact of growing MEC in the lab following their isolation was studied in relation to their population homogeneity and milk synthesis related gene expressions. Upon isolation, flow cytometry results showed that > 30 % of the obtained cells were positive for cytokeratin 18 (CK18), a marker for the MEC. This proportion increased to 95 % MEC after the first passage. Cell functionality was examined by comparing the expressions of milk synthesis related genes at passage 2 (P2) to passage 6 (P6) following treatment with lactogenic agents. CSN1S1 was found to be expressed significantly higher at P2 compared to P6. In addition, CSN2, CSN3 and PRLR tended to have lower expressions in P6 compared to P2. DGAT1, STAT5A, AKT1, and RPS6KB1 were expressed comparably in both passages. The expressions of LALBA and CSN1S2 were not detectable in any of the samples. Therefore, despite having high levels of CK18 positive cells at later passages, in line with other studies, further passaging affected the expressions of some of the genes related to milk synthesis. A reduced gene expression capacity in the propagated MEC may limit their potential for in-vitro milk components production.

Keywords

• Lactating cells
• Cell passage and proliferation
• Milk components
• CK18