Characterization of the uterine leiomyoma microRNAome by deep sequencing

MicroRNAs (miRNAs) are a class of small non-coding RNAs, which are negative regulators of gene expression. Many genes in human uterine leiomyoma (ULM) are aberrantly expressed and in some cases this can be due to dysregulation of miRNAs. Here we present the first study to determine genome-wide miRNA expression patterns in uterine leiomyoma and myometrium using Solexa high-throughput sequencing. We found more than 50 miRNAs, which were differentially expressed, and furthermore we extend the list of putative new miRNA genes. The top five significantly de-regulated miRNAs in ULMs that we found in our libraries were miR-363, miR-490, miR-137, miR-217 and miR-4792. We also observed "isomiRs" with higher copy number than referenced mature miRNA specific for the leiomyoma libraries, which have a potential role in tumorigenesis. The microRNA transcriptomes obtained in this study deliver insights and further expand our understanding the role of small RNAs in uterine leiomyoma development.