The long non-coding RNA H19 promotes cardiomyocyte apoptosis in dilated cardiomyopathy

LncRNA TINCR attenuates cardiac hypertrophy by epigenetically silencing CaMKII

In the previous study, we established a mouse model of cardiac hypertrophy using transverse aortic constriction (TAC) and found that the expression of long non-coding RNAs TINCR was downregulated in myocardial tissue. The present study was designed to determine the potential role of TINCR in the pathogenesis of cardiac hypertrophy. Our results showed that enforced expression of TINCR could attenuate cardiac hypertrophy in TAC mice. Angiotensin II (Ang-II) was found to be associated with reduced TINCR expression and increased hypertrophy in cultured neonatal cardiomyocytes. RNA-binding protein immunoprecipitation assay confirmed that TINCR could directly bind with EZH2 in cardiomyocytes. The results of chromatin immunoprecipitation assay revealed that EZH2 could directly bind to CaMKII promoter region and mediate H3K27me3 modification. Knockdown of TINCR was found to reduce EZH2 occupancy and H3K27me3 binding in the promoter of CaMKII in cardiomyocytes. In addition, enforced expression of TINCR was found to decrease CaMKII expression and attenuate Ang-II-induced cardiomyocyte hypertrophy. Furthermore, our results also showed that Ang-II could increase CaMKII expression in cardiomyocytes, which consequently contributed to cellular hypertrophy. In conclusion, our findings demonstrated that TINCR could attenuate myocardial hypertrophy by epigenetically silencing of CaMKII, which may provide a novel therapeutic strategy for cardiac hypertrophy.

Elevated microRNA-34a contributes to trophoblast cell apoptosis in preeclampsia by targeting BCL-2

Preeclampsia (PE) is one of the most common pregnancy-specific pathologic complications, and is characterised by onset of hypertension and proteinuria. Placental trophoblast cell apoptosis is generally accepted as a major cause of PE. However, the details of the mechanism underlying the condition remain unclear. Here, we aimed to investigate a possible association between microRNA (miR)-34a and human trophoblast cell apoptosis during PE. We evaluated miR-34a expression in placentas from patients with PE compared with those from healthy pregnant individuals. Furthermore, we measured apoptosis rate after miR-34a mimic and/or inhibitor transfection in vitro, and identified B-cell CLL/lymphoma 2 (BCL-2) as a target of miR-34a. We found that miR-34a levels were significantly higher in placental tissues from patients with PE than in normal placentas. Upregulation of miR-34a induced trophoblast cell apoptosis in PE by inhibiting expression of BCL-2 protein. miR-34a inhibition reversed miR-34a-induced apoptosis in the HTR-8/SVneo human trophoblast cell line. Our findings indicate that miR-34a may be linked to the occurrence of PE via effects on BCL-2 in the human placenta, and may therefore provide a potential therapeutic target for PE.