Methionine deficiency reduces autophagy and accelerates death in intestinal epithelial cells infected with enterotoxigenic Escherichia coli

Infections by enterotoxigenic Escherichia coli (ETEC) result in large economic losses to the swine industry worldwide. Dietary supplementation with amino acids has been considered as a potential mechanism to improve host defenses against infection. The goal of this study was to determine whether methionine deprivation alters ETEC interactions with porcine intestinal epithelial cells. IPEC-1 cells were cultured in media with or without l-methionine. Methionine deprivation resulted in enhanced ETEC adhesion and increased both the cytotoxicity and apoptotic responses of IPEC-1 cells infected with ETEC. Methionine deprivation inhibited IPEC-1 cell autophagic responses, suggesting that the increased cytotoxicity of ETEC to methionine-deprived IPEC-1 cells might be due to defects in autophagy.