Lutein improves cell viability and reduces Alu RNA accumulation in hydrogen peroxide challenged retinal pigment epithelial cells

Abstract

Purpose: Dysfunction of the microRNA (miRNA)-processing enzyme DICER1 and Alu RNA accumulation are linked to the pathogenesis of age-related macular degeneration (AMD). This study determined the optimal dose of lutein (LUT) and zeaxanthin (ZEA) to protect human retinal pigment epithelium (RPE) cells against hydrogen peroxide (H₂O₂). The effect of the optimal dose of LUT and ZEA as DICER1 and Alu RNA modulators in cultured human RPE cells challenged with H₂O₂ was investigated.

Materials and methods: ARPE-19 cells were pre-treated with LUT, ZEA, or both for 24 h before 200 μM H₂O₂ challenge. Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. DICER1 and Alu RNA were quantified by western blotting and real-time polymerase chain reaction, respectively.

Results: H₂O₂ increased cell Alu RNA expression and decreased cell viability of ARPE-19, but had no significant impact on the DICER1 protein level. LUT, alone and in combination with ZEA pre-treatment, prior to H₂O₂ challenge significantly improved cell viability of ARPE-19 and reduced the level of Alu RNA compared to the negative control.

Conclusions: These results support the use of LUT alone, and in combination with ZEA, in AMD prevention and treatment. This study is also the first to report LUT modulating effects on Alu RNA.

Keywords:

• Lutein
• zeaxanthin
• ARPE-19
• DICER1
• Alu RNA
• age-related macular degeneration
• hydrogen peroxide

Acknowledgements

The authors are grateful to Dr. Felicia Chung and Dr. Tan Boon Shing (International Medical University) for their assistance with molecular biology techniques.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the International Medical University under Grant number BMS I02/2014 (09).