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Characterization of carnosine uptake and its physiological function in human intestinal epithelial Caco‐2 cells
Author(s) -
Son Dong Ok,
Satsu Hideo,
Kiso Yoshinobu,
Shimizu Makoto
Publication year - 2004
Publication title -
biofactors
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 94
eISSN - 1872-8081
pISSN - 0951-6433
DOI - 10.1002/biof.552210177
Subject(s) - carnosine , caco 2 , antioxidant , secretion , oxidative stress , intestinal mucosa , chemistry , transporter , biochemistry , intestinal epithelium , biology , epithelium , medicine , in vitro , genetics , gene
Carnosine (β‐Ala‐L‐His) is known to have the physiological functions of an antioxidant. Although dietary carnosine is thought to be absorbed across intestinal epithelial cells, the mechanism for this absorption is not yet well understood and its function in the intestinal tract is also obscure. The intestinal transport of carnosine was characterized in the present study by using human intestinal Caco‐2 cells, and its physiological function in these cells was further examined. The carnosine uptake was proton‐dependent, being activated by lowering the apical pH value. Its uptake was significantly inhibited by other dipeptides, whereas it was not inhibited by other amino acids. These characteristics of the carnosine uptake strongly suggest its transport into the cells via peptide transporter 1 (PepT1). Since carnosine has antioxidative activity, we studied its effect on the H 2 O 2 ‐induced secretion of inflammatory cytokines in Caco‐2 cells. The H 2 O 2 ‐induced increase in IL‐8 secretion was inhibited by a pretreatment with carnosine for 3 h, this inhibition being presented in a dose‐dependent manner. These results suggest that carnosine had a protective effect against oxidative stress in intestinal epithelial cells.