Activation of the promoters of genes associated with DNA damage, oxidative stress, ER stress and protein malfolding by the bile salt, deoxycholate

Abstract

Toxic bile salts, retained within the liver because of impaired biliary excretion, are considered to play a major role in liver injury during cholestasis. Bile salts cause cellular stresses that may result in apoptosis. To better understand such cellular stresses, the effect of the bile salt sodium deoxycholate (NaDOC) on activation of 13 specific gene promoters or response elements associated with different cellular stresses was measured in the transformed human hepatoma line, HepG2. NaDOC was found to activate transcription factors and induce or activate the promoters of genes that respond to protein malfolding (grp78 and hsp70), DNA damage (gadd153, hsp70 and c-fos), oxidative stress (NF-kappaB, c-fos, hsp70 and gadd153), ER stress (grp78) and Ca++ imbalance (grp78).