Abstract 3832: Mir429 Regulates NO-dependent Differentiation Of Mouse Embryonic Stem Cells
BACKGROUND: microRNAs (miRs) are emerging as important regulators of many cell functions and, possibly, also embryonic stem cells (ES) differentiation. Recently, it has been shown that specific microRNAs may allow ES to discriminate among different developmental lineages. Nitric oxide is a key regulator of vascular function and induces cardiogenesis in embryonic stem cells; however, no data are available about the effect of NO on microRNAs expression patterns, neither in adult nor in stem cells.
METHODS AND RESULTS: mouse ES were deprived of Leukemia Inhibitory Factor (LIF) and treated with the NO donor diethylenetriamine nitric oxide adduct (DETA/NO) for 90 minutes and microRNA microarray analysis was performed. Among the differentially expressed microRNAs, we focused on miR429, belonging to the miR200 mirRNA family, which regulates epithelial to mesenchymal transition, targeting ZEB transcription factors. ES cells (5x10 5) were exposed from 90 minutes to 24 hours to DETA/NO in the absence of LIF and real time PCR experiments, were performed. We found that miR429 progressively increased along the whole time course, in the presence of DETA/NO, to be upregulated 8 fold with respect to control cells at the 24 hours time point. Moreover, we found that, consistently with miR429 upregulation, NO treatment down-modulated ZEB2/Sip1 transcription factor expression in ES cells. Both antagomir429 and ZEB2/Sip1 overexpression blocked NO-dependent expression of cardiovascular markers, such as Flk-1 and SM22α, in ES, while inducing ES proliferation, indicating the mir429/ZEB circuitry as an important regulator of ES cell fate. To our knowledge, these data identify the first, NO-dependent, microRNA-based mechanism regulating ES development and indicate ZEB2/Sip1 as a novel, potential “stem” gene.