Mechanical strain stress suppresses expression of HSP70 and wound restoration in gastric mucosal cells.

The major heat shock protein, HSP70, is known to be involved in cytoprotection against environmental stresses mediated by their function as a "molecular chaperone." However, the influence of HSP70 on gastric mucosal healing under physical stimulation or stress is not completely understood. Rat gastric mucosal cells (RGM-1) were stably transfected with pBK-CMV containing the human HSP70 gene (7018-RGM-1) or pBK-CMV alone (pBK-CMV-12). Artificial wounds were created. Mechanical stretch was applied to 7018-RGM-1 cells or pBK-CMV-12 cells. The effect of mechanical stretch on HSP70 expression was assessed by Western blot analysis. Expression of HSP70 was decreased by mechanical stretch in pBK-CMV-12 cells. However, expression of HSP70 was not decreased by mechanical stretch in 7018-RGM-1 cells. Furthermore, the wound restoration of pBK-CMV-12 cells was suppressed under mechanical stretch condition. On the other hand, the wound restoration of 7018-RGM-1 cells was not affected by mechanical stretch. These results suggest that HSP70 plays an important role in gastric wound healing under physical stress.