The objective of this study was to investigate the mechanisms of the transport of antihypertensive tripeptides LKP (Leu-Lys-Pro) and IQW (Ile-Gln-Trp) derived from egg white using a coculture system of Caco-2 and HT29 cell monolayers. The results revealed that LKP and IQW have no cytotoxicity to the cell viability after 2 h incubation, could be transported intact across coculture monolayers (apparent permeability coefficient: (18.11 ± 1.57) × 10-8 and (13.21 ± 1.12) × 10-8 cm/s, respectively), and were resistant to peptidase secreted by enterocytes. In addition, the transports were significantly inhibited by dipeptide Gly-Pro (P < 0.05), a competitive substance of peptide transporter 1 (PepT1). The transports from apical to basolateral side were significantly higher than that of the reverse direction (P < 0.05). These results suggest that PepT1 is involved in LKP and IQW transports. The transports were also significantly decreased by theaflavin-3′-O-gallate (P < 0.05), an enhancer of tight junction (TJ) and increased by cytochalasin D (P < 0.05), a disruptor of TJ but not influenced by wortamanin, a transcytosis inhibitor, suggesting that passive paracellular route via TJs is also involved in LKP and IQW transports but not transcytosis. In addition, siRNA was also used to knockdown the expression of PepT1 and significantly inhibited the transport (P < 0.05), confirming that PepT1 is involved in transport process. Therefore, both passive paracellular route via TJ and active route via PepT1 coexist in the transport of antihypertensive LKP and IQW across Caco-2/HT29 coculture monolayers.
|Number of pages||9|
|Journal||Journal of Agricultural and Food Chemistry|
|State||Published - Aug 30 2017|
Bibliographical noteFunding Information:
*Phone: 780-492-6885. Fax: 780-492-4265. E-mail: jwu3@ ualberta.ca. ORCID Qingbiao Xu: 0000-0001-8461-9924 Jianping Wu: 0000-0003-2574-5191 Funding This research was funded by grants from Alberta Livestock Meat Agency and Natural Science and Engineering Research Council of Canada to J.W. Notes The authors declare no competing financial interest.
© 2017 American Chemical Society.
- antihypertensive peptide
ASJC Scopus subject areas
- Chemistry (all)
- Agricultural and Biological Sciences (all)