Epsilon Archive for Student Projects

Abstract

Milk is primary food of infants and indispensable part of human diet. There is solid evidence of chemicals and drugs presence in milk which raise concerns for toxicological safety of milk. Membrane transporters play key role in the transport of chemicals into milk. Transporters belong to ABC transporter superfamily e.g. Bcrp, Mdr1 and Mrp1 or SLC transporter family e.g. Oatp3 and Octn1. Another considered issue is mastitis which is inflammation of mammary gland usually due to bacterial infection. Two major causes of mastitis are Staphylococcus aureus and Escherichia coli.

In this project we studied gene expression of several ABC transporters; Bcrp1, Mdr1, Mrp1 and SLC transporters Oatp3 and Octn1 in murine mammary epithelial HC11 cells differentiated into secreting phenotype. We compared two different cell differentiation protocols on HC11 cells and their potential effect on gene expression of membrane transporters. We also investigated effects of S. aureus infection and endotoxin treatment (LPS) on gene expression of transporters. Expression of transporters was studied by SYBR Green RT-PCR.

The results showed that both cell differentiation protocols caused a downregulation of Bcrp and Octn1. In addition, cell differentiation protocol I resulted in a downregulation of Mrp1 and upregulation of Oatp3. Furthermore, cell differentiation protocol II resulted in a downregulation of Mdr1. Octn1 was upregulated in presence of S. aureus and Oatp3 by LPS treatment.

In conclusion, HC11 cells were demonstrated to express all the investigated membrane transporters. Some differences between the two evaluated differentiation protocols were detected, regarding gene expression of the membrane transporters. However, a common observation for both differentiation protocols was a downregulation of Bcrp and Octn1. Bacterial infection of HC11 cells resulted in upregulation of Octn1, whereas LPS treatment induced upregulation of Oatp3. Further studies are needed to elucidate the physiological role of reduced Bcrp and Octn1 in secreting HC11 cells and also to confirm the upregulation of Octn1 in S. aureus infected cells and Oatp3 in LPS treated cells.