Role of C/EBP Homologous Protein (CHOP) and Nupr1 Interaction in Endoplasmic Reticulum Stress-Induced Apoptosis of Lens Epithelial Cells.

Our study mainly analyzed the mechanism of C/EBP homologous protein (CHOP) and its interacting protein Nupr1 on endoplasmic reticulum stress (ERS) induced lens epithelial cells (LEC) apoptosis. Cell proliferation was detected by CCK-8. Apoptosis was detected by flow cytometry and TUNEL. Nupr1 expression was detected by RT-qPCR. The expressions of CHOP, Nupr1, apoptosis-related protein, and ERS-related protein were detected by Western blot. DCFH-DA probe was used to detect cell ROS. The SOD, GSH-PX, and MDA contents were detected by the kit. Co-IP was used to detect the interaction between CHOP and Nupr1. The morphology of the lens was detected by HE staining. The result shows that Tunicamycin (TU) can induce endoplasmic reticulum stress and apoptosis in LEC in a concentration-dependent manner. TU induction leads to the occurrence of CHOP nuclear translocation. Overexpression of CHOP can further enhance the inhibitory effect of TU on LEC proliferation and the promotion of apoptosis, while knockdown of CHOP has the opposite effect. CHOP and Nupr1 are interacting proteins, and knockdown of Nupr1 or addition of Nupr1 inhibitor ZZW-115 can reverse the effects of TU and overexpression of CHOP, respectively. It has been observed in animal experiments that treatment with oe-CHOP can further aggravate the pathological lesions of the rat lens, while ZZW-115 can reverse the effect of oe-CHOP to a certain extent and improve the lesions of the rat lens. Overall, CHOP interacts with Nupr1 to regulate apoptosis caused by ERS and mediate cataract progression in rats, and this study provides a new potential therapeutic target for the treatment of cataract.