Effect of thymoquinone on endoplasmic reticulum (ER) stress in NRK-52e cells

Thymoquinone (TQ), the active component of Nigella sativa, has many beneficial effects. The endoplasmic reticulum involved in the quality control of protein translocation and folding can vary under different conditions, the phenomenon of causing the accumulation of unfolded or misfolded proteins within the ER lumen is termed ER stress. This in vitro study was planned to investigate the effect of TQ on ER stress at proliferative (Tp) and toxic (TQ_IC50) concentrations on NRK-52E cells at 24th, 48th hours. The expression of important genes in the ER stress pathway (ATF4, ATF6, BIP, CHOP, IRE1, XBP1, PERK) was analyzed. Expression of all genes except CHOP and XBPI increased at 24 hours and BIP at 48 hours for Tp. In the IC50, the CHOP and XBPI gene expressions increased at the 24th hour, and the CHOP and ATF4 genes increased at the 48th hour. As a result, it was determined that the expression of ER stress genes had significant changes with the TQ induction, depending on time and concentration, especially in the proliferative concentration. It is thought that TQ may have varying effects on healthy kidney cells, and it is important to investigate the mechanism of this effect in further studies.