Identification and characterization of bovine mammary peptide transporters in response to tripeptide and lactogenic hormone treatment

Abstract

Cui Y., Zhang X., Guo C., Du R., Ailun G., Ao C., Gao M. (2017): Identification and characterization of bovine mammary peptide transporters in response to tripeptide and lactogenic hormone treatment. Czech J. Anim. Sci., 62, 296-305.Oligopeptide transportation is mediated by the peptide transporter (PepT), which consists of two isoforms, PepT1 and PepT2. Because PepT play essential roles in amino acid metabolism and cell growth, the aim of the present study was to identify these transporters in bovine mammary glands and to analyze the potential functions of these transporters in mammary epithelial cells. Abundance of PepT1 and PepT2 mRNA was successfully measured in both mammary glands and cultured mammary epithelial cells. In addition, the two proteins were examined using immunohistochemistry, immunocytochemistry, and Western blots. The response of mammary epithelial cells to tripeptide and lactogenic hormone treatment was assayed. The PepT mRNA abundance of cultured epithelial cells and secreted protein in the culture medium were increased after tripeptide substitution and addition of hormones such as insulin, hydrocortisone, and prolactin. The response of mammary epithelial cells to tripeptide and hormone treatments suggests that PepT affects the mammary gland function and increases bovine milk production.

Single-step genome-wide association studies (GWAS) and post-GWAS analyses to identify genomic regions and candidate genes for milk yield in Brazilian Girolando cattle

“…Later studies demonstrated that PEPT2 mRNA and protein are also expressed in lactating and cultured bovine mammary gland epithelial cells. Coupled with lactogenic hormones (prolactin, hydrocortisone, and insulin), gene expression of PEPT2 was significantly enhanced (Zhou et al, 2011;Cui et al, 2017). In the bovine mammary gland, reabsorption of peptides is very important for milk protein synthesis, in which PEPT2 is essential to maintain peptide homeostasis and to reduce drug contamination in milk, especially during lactation (Zhou et al, 2011).…”

“…In the bovine mammary gland, reabsorption of peptides is very important for milk protein synthesis, in which PEPT2 is essential to maintain peptide homeostasis and to reduce drug contamination in milk, especially during lactation (Zhou et al, 2011). Thus, the PEPT2 gene might influence milk production in cattle (Yang et al, 2015;Cui et al, 2017).…”

Enhancing Milk Production by Nutrient Supplements: Strategies and Regulatory Pathways

“…Dipeptide (Methionyl-Methionine) positively affects JAK2-STAT5 and mTOR signaling pathways in BMECs after being absorbed by PepT2, thereby promoting β-casein synthesis and cell proliferation [84]. Studies also showed that after stimulation of BMECs with tripeptides and lactogenic hormones, the abundance of PepT1 and PepT2 can be increased, thereby promoting milk fat synthesis [85,86]. In addition, it has been shown that OPH3-1, a fraction of the octopus protein hydrolysis product bioactive peptide, promotes mammary epithelial cell proliferation and casein synthesis in mice [87].…”

Identification of octopus peptide and its promotion of β‐casein synthesis in a mouse mammary epithelial cell line

“…Several studies showed that peptides appear to be more efficient than free amino acid in promoting milk protein synthesis (Chen et al, 2020;Zhou et al, 2015;Zhou et al, 2020). This may be related to the action of aminopeptidase N and peptide transporter (Cui et al, 2017;Liu, Wang, Wang, Li, & Cao, 2010;Wang, Zhao, Liu, & Liu, 2016). Figure S1 shows the separation of fraction OPH3-1 into six portions labeled F1-F6 with RP-HPLC for further peptidomic profiling.…”

“…Overall, the peptide‐bound amino acid including Met, Phe, or Thr is necessary for the synthesis of milk protein. It is likely that either the peptides could be hydrolyzed extracellularly with the subsequent uptake of the component amino acids, di‐ or tri‐peptides, or the peptides could be completely transported into mammary secretory cells by the peptide transporter (Cui et al., 2017; Shennan & Boyd, 2014; Wang, Sun, Zhao, Liu, & Liu, 2019).…”