Cripto Is Targeted by miR-1a-3p in a Mouse Model of Heart Development

: During cardiac differentiation, numerous factors contribute to the development of the heart. Understanding the molecular mechanisms underlying cardiac development will help combat cardiovascular disorders, among the leading causes of morbidity and mortality worldwide. Among the main mechanisms, we indeed find Cripto. Cripto is found in both the syncytiotrophoblast of ampullary pregnancies and the inner cell mass along the primitive streak as the second epithelial-mesenchymal transformation event occurs to form the mesoderm and the developing myocardium. At the same time, it is now known that cardiac signaling pathways are intimately intertwined with the expression of myomiRNAs, including miR-1. This miR-1 is one of the muscle-specific miRs; aberrant expression of miR-1 plays an essential role in cardiac diseases. Given this scenario, our study aimed to evaluate the inverse correlation between Cripto and miR-1 during heart development. We used in vitro models of the heart, represented by embryoid bodies (EBs) and embryonic carcinoma cell lines derived from an embryo-derived teratocarcinoma in mice (P19 cells), respectively. First, through a luciferase assay, we demonstrated that Cripto is a target of miR-1. Following this result, we observed that as the days of differentiation increased, the Cripto gene expression decreased, while the level of miR-1 increased; furthermore, after silencing miR-1 in P19 cells, there was an increase in Cripto expression. Moreover, inducing damage with a cobra cardiotoxin (CTX) in post-differentiation cells, we noted a decreased miR-1 expression and increased Cripto. Finally, in mouse cardiac biopsies, we observed by monitoring gene expression the distribution of Cripto and miR-1 in the right and left ventricles. These results allowed us to detect an inverse correlation between miR-1 and Cripto that could represent a new pharmacological target for identifying new therapies.