O-GlcNAc Signaling Augmentation Protects Human Corneal Endothelial Cells from Oxidative Stress via AKT Pathway Activation

ABSTRACT

Purpose: To investigate the effect of inhibitor of O-glycosylation on human corneal endothelial cells (HCECs) under oxidative stress.

Methods: HCECs were cultured and treated with 10 mM tert-butyl hydroperoxide (tBHP) with or without PUGNAc, a known inhibitor of OGA. Cell viability was assessed. Mitochondrial membrane potential (ΔΨ_m) was measured. Intracellular Ca²⁺ levels and mitochondrial Ca²⁺ levels were measured. Intracellular reactive oxygen species formation was measured. Levels of O-linked β-N-acetylglucosamine (O-GlcNAc), AKT, and pAKT were evaluated by Western blotting.

Results: O-GlcNAc augmentation by PUGNAc increased cell viability, attenuated the loss of ΔΨ_m, and intracellular ROS against tBHP-induced oxidative stress (p < .05). O-GlcNAc augmentation reduced tBHP-induced mitochondrial calcium overload (p < .05) while it did not have any effect on intracellular calcium overload with tBHP. Furthermore, AKT signaling was activated in the cells with O-GlcNAc augmentation.

Conclusions: O-GlcNAc signaling augmentation protects HCECs from oxidative stress via activation of AKT pathways.

KEYWORDS:

• Corneal endothelial cells
• corneal endothelial wound healing
• O-linked β-N-acetylglucosamine
• oxidative stress
• AKT pathway

Conflicts of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

This research was supported by the National Research Foundation (NRF) grant funded by the Korea government [NRF-2018R1A2B6002251] and Hallym University Research Fund [HURF-2019-05].