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Fan Fan, Yi Luo, Jianhui Zhuang, Xin Liu; MicroRNA-34a promotes mitochondria dysfunction induced apoptosis in human lens epithelial cell by targeting Notch2. Invest. Ophthalmol. Vis. Sci. 2016;57(12):2501.
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© ARVO (1962-2015); The Authors (2016-present)
Human lens epithelial cells (HLECs) apoptosis is a common pathogenic mechanism in age-related cataract (ARC). The role of miRNAs in the eye is beginning to be explored following recent detection by miRNA expression analyses. In this study, we explored the role of miR-34a in regulating the apoptosis in HLECs.
Quantitative real-time PCR (qRT-PCR) was used to determine the expression level of miR-34a and pyrosequencing was performed to dissect the DNA methylation percentages of miR-34a promoter in both cataractous and transparent lenses. MicroRNA mimics and small interfering RNA were transfected into HLECs. In vitro apoptosis, mitochondria function and oxidative stress were assessed in transfected HLECs. The expression of targeted gene was determined by qRT-PCR and western blotting, and confirmed with dual luciferase reporter assay. The potential roles of identified target gene in apoptosis were also evaluated.
The expression of miR-34a was increased in lens epithelial samples of ARC compared to the transparent group, whereas no significant difference in methylation percentages of miR-34a promoter was detected between the two groups. In cultured HLECs, miR-34a increased reactive oxygen species production and induced apoptosis as determined by flow cytometry and stimulation of caspase-3,7 activity. Overexpression of miR-34a promoted mitochondria-involved apoptosis through activation of caspase 9, disruption of mitochondria membrane potential and enhancement of cytochrome C release. Furthermore, miR-34a inhibited Notch1/Notch2 expression and targeted 3’ un-translational region of Notch1/Notch2 mRNA. Otherwise, knockdown of Notch2 but not Notch1 could trigger mitochondria-involved apoptosis.
MicroRNA-34a is increased in cataratous lens and may be involved in mitochondria-mediated apoptosis and oxidative stress by targeting Notch2.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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