Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany; Genome Institute of Singapore, 138672, Singapore.
Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany; Department of Cardiovascular Surgery, University Heart Center, 20246 Hamburg, Germany.
J Mol Cell Cardiol. 2018 Jul;120:53-63. doi: 10.1016/j.yjmcc.2018.05.012. Epub 2018 May 21.
Heart failure is associated with altered gene expression and DNA methylation. De novo DNA methylation is associated with gene silencing, but its role in cardiac pathology remains incompletely understood. We hypothesized that inhibition of DNA methyltransferases (DNMT) might prevent the deregulation of gene expression and the deterioration of cardiac function under pressure overload (PO). To test this hypothesis, we evaluated a DNMT inhibitor in PO in rats and analysed DNA methylation in cardiomyocytes.
Young male Wistar rats were subjected to PO by transverse aortic constriction (TAC) or to sham surgery. Rats from both groups received solvent or 12.5 mg/kg body weight of the non-nucleosidic DNMT inhibitor RG108, initiated on the day of the intervention. After 4 weeks, we analysed cardiac function by MRI, fibrosis with Sirius Red staining, gene expression by RNA sequencing and qPCR, and DNA methylation by reduced representation bisulphite sequencing (RRBS). RG108 attenuated the ~70% increase in heart weight/body weight ratio of TAC over sham to 47% over sham, partially rescued reduced contractility, diminished the fibrotic response and the downregulation of a set of genes including Atp2a2 (SERCA2a) and Adrb1 (beta1-adrenoceptor). RG108 was associated with significantly lower global DNA methylation in cardiomyocytes by ~2%. The differentially methylated pathways were "cardiac hypertrophy", "cell death" and "xenobiotic metabolism signalling". Among these, "cardiac hypertrophy" was associated with significant methylation differences in the group comparison sham vs. TAC, but not significant between sham+RG108 and TAC+RG108 treatment, suggesting that RG108 partially prevented differential methylation. However, when comparing TAC and TAC+RG108, the pathway cardiac hypertrophy was not significantly differentially methylated.
DNMT inhibitor treatment is associated with attenuation of cardiac hypertrophy and moderate changes in cardiomyocyte DNA methylation. The potential mechanistic link between these two effects and the role of non-myocytes need further clarification.
心力衰竭与基因表达和 DNA 甲基化的改变有关。新合成的 DNA 甲基化与基因沉默有关，但它在心脏病理学中的作用仍不完全清楚。我们假设，抑制 DNA 甲基转移酶（DNMT）可能会防止在压力超负荷（PO）下基因表达的失调和心脏功能的恶化。为了验证这一假设，我们在 PO 大鼠中评估了一种 DNMT 抑制剂，并分析了心肌细胞中的 DNA 甲基化。
年轻雄性 Wistar 大鼠通过横主动脉缩窄（TAC）或假手术进行 PO。两组大鼠均在干预当天接受溶剂或 12.5mg/kg 体重的非核苷类 DNMT 抑制剂 RG108。4 周后，我们通过 MRI 分析心脏功能，用 Sirius Red 染色分析纤维化，通过 RNA 测序和 qPCR 分析基因表达，通过简化代表性双硫代嘧啶测序（RRBS）分析 DNA 甲基化。RG108 使 TAC 相对于假手术的心脏重量/体重比增加约 70%降低至 47%，部分挽救了收缩功能降低，减少了纤维化反应和一组基因的下调，包括 Atp2a2（SERCA2a）和 Adrb1（beta1-肾上腺素能受体）。RG108 使心肌细胞的总体 DNA 甲基化降低约 2%。差异甲基化的途径是“心肌肥厚”、“细胞死亡”和“异生物质代谢信号”。在这些途径中，“心肌肥厚”在 sham 与 TAC 的组间比较中与显著的甲基化差异相关，但在 sham+RG108 与 TAC+RG108 治疗之间没有显著差异，表明 RG108 部分阻止了差异甲基化。然而，当比较 TAC 和 TAC+RG108 时，心肌肥厚途径并没有显著的差异甲基化。
DNMT 抑制剂治疗与心肌肥厚的减轻和心肌细胞 DNA 甲基化的适度变化有关。这两种效应之间的潜在机制联系以及非心肌细胞的作用需要进一步阐明。
