High glucose causes apoptosis of rabbit corneal epithelial cells involving activation of PERK-eIF2α-CHOP-caspase-12 signaling pathway

Pan-Pan Yao; Min-Jie Sheng; Wen-Hao Weng; Yin Long; Hao Liu; Li Chen; Jia-Jun Lu; Ao Rong; Bing Li

doi:10.18240/ijo.2019.12.01

High glucose causes apoptosis of rabbit corneal epithelial cells involving activation of PERK-eIF2α-CHOP-caspase-12 signaling pathway

Int J Ophthalmol. 2019 Dec 18;12(12):1815-1822. doi: 10.18240/ijo.2019.12.01. eCollection 2019.

Authors

Pan-Pan Yao¹, Min-Jie Sheng¹, Wen-Hao Weng², Yin Long², Hao Liu¹, Li Chen¹, Jia-Jun Lu³, Ao Rong³, Bing Li¹

Affiliations

¹ Department of Ophthalmology, Yangpu Hospital, Tongji University School of Medicine, Shanghai 200090, China.
² Department of Clinical Laboratory, Yangpu Hospital, Tongji University School of Medicine, Shanghai 200090, China.
³ Department of Ophthalmology, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China.

Abstract

Aim: To investigate the effect of high concentration of glucose (HCG) on double stranded RNA-activated protein kinase-like ER kinase (PERK)-eukaryotic initiation factor-2α (eIF2α)-transcription factor C/EBP homologous protein (CHOP)-cysteine aspartate specific proteinase (caspase-12) signaling pathway activation and apoptosis in rabbit corneal epithelial cells (RCECs).

Methods: RCECs were treated by different concentrations of glucose for 0-48h. The expressions of PERK, p-PERK, eIF2α, p-eIF2α, 78 kDa glucose-regulated protein 78 (GRP78), CHOP, B-cell lymphoma 2 (Bcl-2), B-cell lymphoma-2-associated X protein (Bax) and caspase-12 were determined by Western blot. Apoptosis was detected by TUNEL assay. Meanwhile, the function of PERK-eIF2α-CHOP-caspase-12 signaling pathway activation in high glucose-induced apoptosis was evaluated using PERK inhibitor, GSK2606414.

Results: HCG significantly promoted the expression of p-PERK, p-eIF2α, GRP78, CHOP, Bax and cleaved caspase-12 in RCECs (P<0.05), while remarkably decreased the expression of Bcl-2 and caspase-12 (P<0.05), and the alterations caused by glucose were in concentration- and time-dependent manners. Meanwhile, PERK and eIF2α expressions were not affected in all groups (P>0.05). TUNEL assay showed that the apoptosis rate of RCECs in the HCG group increased significantly in contrast with that in the normal concentration of glucose or osmotic pressure control group (P<0.05), and the apoptosis rate increased with the increase of glucose concentration within limits (P<0.05). GSK2606414 down-regulated the expression of p-PERK and p-eIF2α in the HCG group (P<0.05), while still did not affect the expression of PERK and eIF2α among groups (P>0.05). Correspondingly, GSK2606414 also significantly reduced the apoptosis rate induced by high glucose (P<0.05).

Conclusion: HCG activates PERK-eIF2α-CHOP-caspase-12 signaling pathway and promotes apoptosis of RCECs.

Keywords: PERK-eIF2α-CHOP-caspase-12 pathway; apoptosis; high glucose; rabbit corneal epithelial cells.

International Journal of Ophthalmology Press.