MicroRNA-1-Mediated Inhibition of Cardiac Fibroblast Proliferation Through Targeting Cyclin D2 and CDK6

Abstract

MicroRNA-1 (miRNA-1) has been long viewed as a muscle-specific miRNA and plays a critical role in myocardium and cardiomyocytes by controlling myocyte growth and rhythm. We identified that miRNA-1 is expressed in cardiac fibroblasts, which are one of the major non-muscle cell types in myocardium and are responsible for cardiac fibrosis in pathological conditions. In this study, we aimed to investigate the effect and mechanism of action of miRNA-1 on cardiac fibroblast proliferation. Subcutaneous angiotensin II (Ang II) infusion via osmotic minipumps for 4 weeks was used to induce myocardial interstitial fibrosis in male Sprague-Dawley rats. MiRNA-1 expression was significantly down-regulated by 68% in freshly isolated ventricular fibroblasts from Ang II-infused rats than that from control rats. Similar results were obtained in adult rat ventricular fibroblasts that were stimulated in culture by Ang II or TGFβ for 48 h. Functionally, overexpression of miRNA-1 inhibited fibroblast proliferation, whereas knockdown of endogenous miRNA-1 increased fibroblast proliferation. We then identified and validated cyclin D2 and cyclin-dependent kinase 6 (CDK6) as direct targets of miRNA-1 in cardiac fibroblasts using biochemical assays. Moreover, we showed that the inhibitory effects of miRNA-1 on cardiac fibroblast proliferation can be blunted by overexpression of its target, cyclin D2. In conclusion, our findings demonstrate miRNA-1 expression and regulation in adult ventricular fibroblasts, where it acts as a novel negative regulator of adult cardiac fibroblast proliferation that is at least partially mediated by direct targeting of two cell cycle regulators. Our results expand the understanding of the regulatory roles of miRNA-1 in cardiac cells (i.e., from myocytes to a major non-muscle cells in the heart).

miR-497 inhibits tumor growth and migration of osteosarcoma by targeting plexinA4 and CDK6

“…CDK6 is a member of the CDK family which plays important roles in the major cell-cycle transitions [19,20]. It governs the cell cycle transitions by initiating the phosphorylation of the RB which leads to the release of E2F transcription factors and subsequently activates the transcription of genes required for S-phase entry.…”

Cardioprotective effects of early intervention with sacubitril/valsartan on pressure overloaded rat hearts

“…Transthoracic echocardiography was performed after 4-week and 10-week treatment using a Vevo2100 (Fujifilm VisualSonics, Toronto, Canada) echocardiography system with a MS250 probe as we described previously 25 . Animals were lightly anesthetized using 1.5–2% isoflurane.…”

Potential roles of microRNA-1 and microRNA-133 in cardiovascular disease

“…In embryonic stem cells, miR-1 and miR-133 synergistically induce the formation of mesoderm (Xin et al, 2013), whereas their lack of function leads to a variety of heart defects and death (Hagiwara et al, 2014). High expression of miR-1 and miR-133 in the injured heart plays a crucial role in cardiovascular pathophysiology (Valkov et al, 2019;Zhang et al, 2019).…”

“…MiRNA is a kind of endogenous, short (18-24 nucleotides), highly conserved non-coding RNA (Valkov et al, 2019). Primaryprecursor miRNAs are transcribed from the genomic region by pol II and subsequently cleaved into precursor miRNAs via Drosha/DGCR8 compound.…”

“…Currently, there are more than 2000 human miRNAs that have been found, which seem to control about 60% of human genes (Shi and Yang, 2016). In rare cases, miRs can stimulate the translation of mRNA, but they typically regulate the expression of target genes negatively by promoting mRNA degradation and/or inhibiting mRNA translation (Valkov et al, 2019).…”