BioProject

Chronic endoplasmic reticulum (ER) stress results in toxicity that contributes to multiple human disorders. More...

Chronic endoplasmic reticulum (ER) stress results in toxicity that contributes to multiple human disorders. We report a stress resolution pathway initiated by the nuclear receptor LRH-1 that is independent of known unfolded protein response (UPR) pathways. Like mice lacking primary UPR components, hepatic Lrh-1-null mice cannot resolve ER stress, despite a functional UPR. In response to ER stress, LRH-1 induces expression of the kinase Plk3, which phosphorylates and activates the transcription factor ATF2. Plk3-null mice also cannot resolve ER stress, and restoring Plk3 expression in Lrh-1-null cells rescues ER stress resolution. Reduced or heightened ATF2 activity also sensitizes or desensitizes cells to ER stress, respectively. LRH-1 agonist treatment increases ER stress resistance and decreases cell death. We conclude that LRH-1 initiates a novel pathway of ER stress resolution that is independent of the UPR, yet equivalently required. Targeting LRH-1 may be beneficial in human disorders associated with chronic ER stress. Overall design: 12 total samples. One sample represents one mouse. Three samples were analyzed from the following groups: Lrh-1 f/f (control littermates) treated with vehicle, Lrh-1 f/f treated with tunicamycin (TM; 1mg/kg BW for 24h), Lrh-1 liver-specific KO mice (LKO) treated with vehicle, and Lrh-1 LKO treated with tunicamycin. Less...