| First Author | Peng Y | Year | 2014 |
| Journal | Cardiovasc Res | Volume | 103 |
| Issue | 2 | Pages | 258-67 |
| PubMed ID | 24835278 | Mgi Jnum | J:230021 |
| Mgi Id | MGI:5755228 | Doi | 10.1093/cvr/cvu126 |
| Citation | Peng Y, et al. (2014) Critical roles of miRNA-mediated regulation of TGFbeta signalling during mouse cardiogenesis. Cardiovasc Res 103(2):258-67 |
| abstractText | AIMS: MicroRNAs (miRNAs) play critical roles during the development of the cardiovascular system. Blocking miRNA biosynthesis in embryonic hearts through a conditional gene inactivation approach led to differential cardiac defects depending on the Cre drivers used in different studies. The goal of this study is to reveal the cardiogenic pathway that is regulated by the miRNA mechanism at midgestation, a stage that has not been evaluated in previous publications. METHODS AND RESULTS: We specifically inactivated Dicer1, which is essential for generation of functional mature miRNAs, in the myocardium by crossing cTnt-Cre mice with Dicer1(loxP) mice. cTnt-Cre efficiently inactivates target genes in cardiomyocytes at midgestation. All mutants died between E14.5 and E16.5 with severe myocardial wall defects, including reduced cell proliferation, increased cell death, and spongy myocardial wall. Expression of TGFbeta type I receptor (Tgfbr1), which encodes the Type I receptor of TGFbeta ligands, was up-regulated in mutant hearts. As expected, TGFbeta activity was increased in Dicer1-inactivated hearts. Our further molecular analysis suggested that Tgfbr1 is a direct target of three miRNAs. Reducing TGFbeta activities using a pharmacological inhibitor on in vitro cultured hearts, or through an in vivo genetic approach, partially rescued the cardiac defects caused by Dicer1 inactivation. CONCLUSIONS: We show for the first time that TGFbeta signalling is directly regulated by the miRNA mechanism during myocardial wall morphogenesis. Increased TGFbeta activity plays a major role in the cardiac defects caused by myocardial deletion of Dicer1. Thus, miRNA-mediated regulation of TGFbeta signalling is indispensable for normal cardiogenesis. |
