miR-211 regulates the antioxidant function of lens epithelial cells affected by age-related cataracts

Bo Lu; Ian T Christensen; Li-Wei Ma; Tao Yu; Ling-Feng Jiang; Chun-Xia Wang; Li Feng; Jin-Song Zhang; Qi-Chang Yan; Xin-Ling Wang

doi:10.18240/ijo.2018.03.01

miR-211 regulates the antioxidant function of lens epithelial cells affected by age-related cataracts

Int J Ophthalmol. 2018 Mar 18;11(3):349-353. doi: 10.18240/ijo.2018.03.01. eCollection 2018.

Authors

Affiliations

¹ Department of Ophthalmology, the Fourth Affiliated Hospital of China Medical University; Key Laboratory of Lens Research of Liaoning Province, Eye Hospital of China Medical University, Shenyang 110005, Liaoning Province, China.
² University of Utah School of Medicine, Salt Lake City, Utah 84132, USA.
³ Department of Medical Imaging, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, Shenyang 110042, Liaoning Province, China.

Abstract

Aim: To investigate the effects and mechanism of miR-211 in mediating the antioxidant function of lens epithelial cells affected by age-related cataracts.

Methods: Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect miR-211 expression in the anterior lens capsules of healthy people, the anterior lens capsules of patients with age-related cataracts, and human epithelial cell line (SRA01/04) cells exposed to oxidative stress. A 2', 7'-dichloro-fluorescein diacetate (DCFH-DA) probe was used to measure the levels of endogenous reactive oxygen species (ROS) in human lens epithelial cells (hLECs) exposed to 400 µmol/L H₂O₂ for 1h. SRA01/04 cells were transfected with either miR-211 mimics, mimic controls, miR-211 inhibitors or inhibitor controls. After 72h, these cells were exposed to 400 µmol/L H₂O₂ for 1h, then p53 and Bax mRNA expression were measured using RT-qPCR. p53 and Bax protein expression were also measured by Western blotting analysis. Finally, cell viability was assessed using an MTS assay.

Results: Compared to the control group, expression of miR-211 in the anterior lens capsules of age-related cataract patients and in SRA01/04 cells exposed to oxidative stress was significantly increased (P<0.001). Levels of endogenous ROS were significantly elevated in hLECs exposed to oxidative stress (P<0.001). Compared to the mimic control group, the hLECs in the miR-211 mimic group expressed significantly higher levels of p53 and Bax mRNA and protein while cell viability was significantly reduced (P<0.001). Conversely, p53 and Bax mRNA and protein expression were significantly reduced in the miR-211 inhibitor group as compared to the control group, while the cells in this group had much higher levels of cell viability (P<0.001).

Conclusion: miR-211 is upregulated in the anterior lens capsules of age-related cataract patients. miR-211 decreased the antioxidative stress capacity of lens epithelial cells by upregulating p53 and Bax, while inhibiting cell proliferation and repair. This finding suggests that miR-211 may play a key role in the development of age-related cataracts.

Keywords: Bax; age-related cataract; miR-211; oxidative stress; p53.