Threonine treatment increases heat shock protein 25 and 70 expression and decreases apoptosis in heat stressed intestinal epithelial cells

Abstract

Osmotically acting amino acids can be cytoprotective following injury in vitro and in vivo. Heat shock proteins (HSPs) have been implicated as one mechanism of protection in these models. Threonine (THR) is necessary for mucin production and gut function but it's effects on HSPs are unknown. Our purpose was to investigate if THR can protect Intestinal Epithelial‐18 cells (IEC‐18) from lethal heat stress (HS) and to elucidate it's mechanism of protection. Cells were treated for 15 min +/− THR and subsequent HS injury. Cell size was evaluated via microscopy. Survival was evaluated via MTS assay and cleaved caspase‐3 (CC3). Western blot analysis was used for CC3, HSP25, and HSP70 levels. THR increased survival in a dose dependent manner (p<0.02 vs. HS alone). THR increased cell size by more than 40% (p<0.001 vs. non‐THR groups). THR decreased CC3 more than 54%, and increased HSP25 and HSP70 levels more than 5 fold in HS (p<0.02 vs. HS alone). This is the first demonstration that THR can decrease apoptosis in heat stressed intestinal cells. THR induces cell swelling and it's effects on HSP25 and HSP70 may be an integral component of THR's mechanism of cellular protection.Grant Funding Source : NIH