Induction of Heat Shock Proteins and Their Implication in Protection Against Ethanol-induced Damage in Cultured Guinea Pig Gastric Mucosal Cells

The induction of heat shock proteins in cultured guinea pig gastric mucosal cells was investigated to assess their role in gastric cytoprotection. In response to sublethal heat stress at 43 degrees C for 1 hour, the cells synthesized a 72-kilodalton protein and increased the synthesis of 74- and 90-kilodalton proteins, which were detected using gel electrophoresis after [35S]methionine labeling of the cells. Immunoblot analysis indicated that the 72- and 74-kilodalton proteins were members of the heat shock protein 70 family. Northern blot analysis showed the induction of a 2.6-kilobase messenger RNA of heat shock protein 70 gene only with heat treatment. Furthermore, with heat treatment, there was significant reduction of damage after ethanol treatment. This reduction was blocked with a protein synthesis inhibitor, cycloheximide, and was associated with inhibition of synthesis of heat shock proteins. These results strongly suggest that synthesis of heat shock proteins plays an important role in the intracellular mechanism of gastric protection against ethanol.