Barbati Saviana A, Colussi Claudia, Bacci Lorenza, Aiello Aurora, Re Agnese, Stigliano Egidio, Isidori Andrea M, Grassi Claudio, Pontecorvi Alfredo, Farsetti Antonella, Gaetano Carlo, Nanni Simona
Institute of Human Physiology, Università Cattolica di Roma, 00168 Rome, Italy.
Institute of Medical Pathology, Università Cattolica di Roma, 00168 Rome, Italy.
Endocrinology. 2017 Jul 1;158(7):2391-2405. doi: 10.1210/en.2016-1960.
This study aims at investigating the epigenetic landscape of cardiomyocytes exposed to elevated glucose levels. High glucose (30 mM) for 72 hours determined some epigenetic changes in mouse HL-1 and rat differentiated H9C2 cardiomyocytes including upregulation of class I and III histone deacetylase protein levels and activity, inhibition of histone acetylase p300 activity, increase in histone H3 lysine 27 trimethylation, and reduction in H3 lysine 9 acetylation. Gene expression analysis focused on cardiotoxicity revealed that high glucose induced markers associated with tissue damage, fibrosis, and cardiac remodeling such as Nexilin (NEXN), versican, cyclic adenosine 5'-monophosphate-responsive element modulator (CREM), and adrenoceptor α2A (ADRA2). Notably, the transcription factor CREM was found to be important in the regulation of cardiotoxicity-associated genes as assessed by specific small interfering RNA and chromatin immunoprecipitation experiments. In CD1 mice, made hyperglycemic by streptozotoicin (STZ) injection, cardiac structural alterations were evident at 6 months after STZ treatment and were associated with a significant increase of H3 lysine 27 trimethylation and reduction of H3 lysine 9 acetylation. Consistently, NEXN, CREM, and ADRA2 expression was significantly induced at the RNA and protein levels. Confocal microscopy analysis of NEXN localization showed this protein irregularly distributed along the sarcomeres in the heart of hyperglycemic mice. This evidence suggested a structural alteration of cardiac Z-disk with potential consequences on contractility. In conclusion, high glucose may alter the epigenetic landscape of cardiac cells. Sildenafil, restoring guanosine 3', 5'-cyclic monophosphate levels, counteracted the increase of CREM and NEXN, providing a protective effect in the presence of hyperglycemia.
本研究旨在探究暴露于高糖水平下的心肌细胞的表观遗传格局。高糖（30 mM）处理72小时可导致小鼠HL-1和大鼠分化的H9C2心肌细胞发生一些表观遗传变化，包括I类和III类组蛋白去乙酰化酶蛋白水平及活性上调、组蛋白乙酰转移酶p300活性受抑制、组蛋白H3赖氨酸27三甲基化增加以及H3赖氨酸9乙酰化减少。聚焦心脏毒性的基因表达分析显示，高糖诱导了与组织损伤、纤维化和心脏重塑相关的标志物，如Nexilin（NEXN）、多功能蛋白聚糖、环磷酸腺苷反应元件调节剂（CREM）和肾上腺素能α2A受体（ADRA2）。值得注意的是，通过特异性小干扰RNA和染色质免疫沉淀实验评估发现，转录因子CREM在心脏毒性相关基因的调控中起重要作用。在通过注射链脲佐菌素（STZ）诱导高血糖的CD1小鼠中，STZ处理6个月后心脏结构改变明显，且与H3赖氨酸27三甲基化显著增加及H3赖氨酸9乙酰化减少相关。同样，NEXN、CREM和ADRA2在RNA和蛋白质水平均显著诱导表达。对NEXN定位的共聚焦显微镜分析显示，该蛋白在高血糖小鼠心脏的肌节中分布不规则。这一证据提示心脏Z盘的结构改变可能对收缩性产生潜在影响。总之，高糖可能会改变心脏细胞的表观遗传格局。西地那非可恢复环磷酸鸟苷水平，抵消CREM和NEXN的增加，在高血糖情况下起到保护作用。
