Abstract
Purpose: :
MicroRNAs (miRNA) are a class of small, endogenous RNA molecules that negatively regulate gene expression post-transcriptionally. They play an important role in the developmental and physiological processes in several organs and tissues. Recent studies have identified altered miRNA expression profiles in a murine model of retinal degeneration. Here we tested whether miRNA expression in macular retinal pigment epithelial (RPE) cells from AMD donor eyes exhibit a different pattern compared to normal aged donor eyes.
Methods: :
We evaluated the expression changes of miRNAs in macular RPE cells from AMD and normal aged human donor eyes using miRNA arrays. The severity of AMD in donor eyes was assessed with the Minnesota Grading System. Paired array analyses were carried out between AMD and aged matched control using 856 miRNAs probes listed in Sanger miRBase (release 11.0). Statistical analysis of up and down regulated transcripts was used to identify the target genes that may be related to AMD.
Results: :
Our data show a different miRNA expression profile in macular RPE cells harvested from AMD donor eyes compared to normal age-matched donor eyes. 21 miRNA were significantly down regulated and 22 miRNA were significantly unregulated in macular RPE cells from AMD donor eyes. This set of differential miRNA between AMD and aged matched control donors were confirmed by Northern Blot or quantitative reverse transcription (qRT)-PCR analyses. Bioinformatics analysis demonstrated the target genes of this set of miRNA, which may be associated with AMD.
Conclusions: :
We discovered significant alterations in miRNA expression in macular RPE cells from AMD compared to aged matched control donor eyes. Activation of this negative regulatory program may alter gene expressions in RPE cells and contribute to the pathogenesis of AMD.
Keywords: retinal pigment epithelium • age-related macular degeneration • gene/expression