Hsa-miR-۱۳۳b Expression Profile during Cardiac Progenitor Cell Differentiation and its Inhibitory Effect on SRF Expression

Objective: Cardiac cell differentiation with the help of miRNAs has recently opened a promising window for the restoration of myocardial infarction. Independent miR-۱-۲/۱۳۳a-۱ and miR-۲۰۶/۱۳۳b clusters are known to be expressed in cardiac and skeletal muscles, respectively. miR-۱۳۳b differs from miR-۱۳۳a by only one nucleotide. The sequence similarity of these two miRNAs suggests that they target the same pathways and similar mRNA targets. The present study seeks to determine if miR-۱۳۳b is expressed during the cardiac cell differentiation and if its expression is in reverse correlation with the SRF and CCND۲ (as potential target genes) expression patterns. Methods: Human cardiac progenitor cells were prepared from Royan Stem Cell Bank (RSCB) and differentiated into cardiomyocytes. To initiate differentiation, cells were treated with ۵-azacytidine as a demethylation factor. Then, ascorbic acid and TGFB۱ were added every other day and twice per week, respectively. Differentiation into cardiomyocytes was confirmed by immunocytochemistry (ICC), flow cytometry and real-time PCR for some of the cardiac marker genes. The expression profiles of hsa-miR-۱۳۳b and two of its potential target genes were also analyzed during the cardiac differentiation. Results: Three weeks after the first differentiation induction, expression level of hsa-miR-۱۳۳b was approximately five times higher than early stage expression (phsa-miR-۱۳۳b expression. Conclusion: It is known that SRF is critically involved in the cell cycle. Considering increased miR-۱۳۳b and decreased SRF expression levels during the late stages of heart cell differentiation, here we speculate that elevated expression of miR-۱۳۳b blocks SRF expression and decreases cardiomyocytes proliferation in order to induce differentiation with direct targeting of SRF. Taken together, our data suggest that miR-۱۳۳b along with miR-۱۳۳a may be involved in cardiomyocytes differentiation.

کلیدواژه ها:

hsa-miR-۱۳۳b ، Cardiac progenitor cells ، Differentiation ، Cardiomyocytes ، hsa-miR-۱۳۳b ، تمایز ، سلولهای مولد قلبی ، سلولهای ماهیچه قلبی