P-44: Important Role of MicroRNA 21 in Heart Development of Down Syndrome Individual (Pages: 60-60)

Bagheri M *, Fathi M , Parvin F , Koohi V , Mohamadi B ,


Objective: Down syndrome (DS) is one of the more common chromosomal disorders and includes some degree of mental defect. It is caused by the presence of an additional chromosome 21, causing the affected person to have three and not the normal two and hence is referred to as Trisomy 21. It occurs in approximately 1 in 800 live births. Discovered just over a decade ago, microRNA (miRNA) is now recognized as one of the major regulatory gene families in eukaryotic cells. Previous studies of cardiac disease have focused on microRNAs that are primarily expressed in cardiomyocytes; the role of microRNAs expressed in other cell types of the heart is unclear. Thomas Thum et al. showed that microRNA-21 (miR-21, also known as Mirn21) regulates the ERK–MAP kinase signalling pathway in cardiac fibroblasts, which has impacts on global cardiac structure and function. This finding triggers us to propose to test this small non-coding regulatory RNA in individuals with Down syndrome. Materials and Methods: We have performed qRT-TaqMan PCR analysis of human mRNA and selected miR-21. These findings reveal that microRNA can contribute to myocardial disease by an effect in cardiac fibroblasts. Results: We demonstrate that mature miR-21 is over-expressed in human samples from individuals with DS. Conclusion: Application of the innovative genomic technologies in studies of small regulatory RNA may help to identify new molecular markers and therapeutic approaches or unmask the new aspects in pathogenesis of common heart disorders