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Shambhu D. Varma, Svitlana Kovtun, Kavita R. Hegde, Jing Yin; MicroRNA Repertoire Of Lens. Effect Of Galactose Feeding. Invest. Ophthalmol. Vis. Sci. 2012;53(14):3042.
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© ARVO (1962-2015); The Authors (2016-present)
Intraocular generation of reactive oxygen species (ROS) plays a pivotal role in the etiology of cataracts. While ROS can induce oxidative stress by rendering many enzymatic and structural proteins dysfunctional by inflicting oxidative modifications, such dysfunctions can also be exerted by up or down regulation of micro RNAs (miRs) that affect mRNAs translational activity by hybridization with it through their 3’-UTRs. The objective of this study was therefore to study the up/down regulation of miRNA in the lens as affected by galactose feeding- a strong cataractogenic agent.
Young mice weighing~20 g were divided into three groups of six each (Control, control + 20% galactose diet with and without 1% pyruvate. Lenses were harvested on day15. mi RNA enriched RNA was prepared using Qiagen reagent. The first strand cDNAs were than synthesized and analyzed by microarray technology using the 96 well mi-finder array plate supplied by SA-Biosciences.
As summarized in table 1, 17 miRs were found to be highly upregulated in the galactose group with 7 being down regulated. The majority of the upregulated miRNAs are known to be highly pro-apoptotic including miR-16 and miR-21. The downregulated ones act primarily as repressors. Legend for Table 1: Differential expression of miRs between normal (control) and galactose fed (Gal G1) mice lenses based on Ct values. High Ct indicates downregulation and vice versa.
The presence of at least 84 miRs has been documented for the first time. It is apparent that cataract formation is linked to activation of several proapoptotic miRs. Correlation with corresponding mRNAs is being followed.
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