Abstract
Purpose: :
The EOMs are a unique group of muscles that are anatomically and physiologically distinct from other skeletal muscles. Strikingly, EOMs show differential susceptibility to disease, exemplified by their preferential sparing in Duchenne’s Muscular Dystrophy (DMD). Previously, we and others have shown that EOMs have a unique transcriptome and proteome. In this study we investigated the expression pattern of microRNAs (miRNAs) at the whole genome level, as they may play a role in generating the unique EOM allotype.
Methods: :
We used microRNA microarray chips (LCSciences) covering the sequences of miRBase 10.0 to define the microRNAome of normal mouse EOM and limb muscle (TA-tibialis anterior). Data of four independent chips were analysed using background substraction, normalization and statistics. Online databases, such as miRBase and TargetScan were used to identify potential miRNA-target pairs.
Results: :
74 miRNAs were found to be differentially regulated based on a p-value of < 0.05 (t-test); 43 miRNAs were up-regulated and 31 miRNAs were down-regulated. Bioinformatic tools and databases were used to integrate the results with our previous transcriptomic and proteomic profiling data. Interestingly, miR-155 which we found to be down-regulated in EOM, has recently been shown to be up-regulated in many primary muscular disorders, including DMD (Eisenberg et al. PNAS 2007).
Conclusions: :
In conclusion, our definition of the distinct and unique EOM microRNAome complements existing data about the molecular make-up of EOM, which will help to explain their differential sensitivity to disease and may assist in development of therapeutic strategies.
Keywords: extraocular muscles: structure • gene microarray • gene/expression