Cell-specific induction of hsp72-mediated protection by glutamine against oxidant injury in IEC18 cells.

Glutamine is a major metabolic fuel and trophic agent for intestinal epithelial cells that can enhance intestinal epithelial cell survival against oxidant and thermal stress, possibly through the induction of heat shock protein 72 (hsp72). In this study, we examined the possibility of a direct causal relationship and tissue specificity of glutamine-induced hsp72. Glutamine treatment of intestinal (epithelial) IEC18 cells, but not HeLa (epidermoid) cells, induces the production of hsp72 in a concentration-dependent fashion, without affecting the expression of the constitutively expressed heat shock protein, hsc73. To determine the specific role that hsp72 induction by glutamine plays in resistance of IEC18 cells to oxidant injury, stable transfected cells expressing an hsp72 antisense construct were established. Although thermal induction of hsp72 was blocked only partially by the antisense construct, glutamine induction of hsp72 was completely inhibited. This was associated with a loss of the protective effects of glutamine against oxidant-induced stress. Thus, glutamine specifically induces hsp72 in intestinal epithelial cells, which mediates cell protection against inflammation-induced stress such as oxidants.