Department of Physiology, West China School of Basic Medical Sciences and Forensic Medicine, Sichuan University, Chengdu, 610041, China.
Department of Cardiology, West China Hospital, Sichuan University, Chengdu, 610041, China.
BMC Cardiovasc Disord. 2023 Nov 7;23(1):541. doi: 10.1186/s12872-023-03583-3.
Runt-related transcription factor-1 (RUNX1), a key member of the core-binding factor family of transcription factors, has emerged as a novel therapeutic target for cardiovascular disease. There is an urgent need to fully understand the expression pattern of Runx1 in the heart and the mechanisms by which it is controlled under normal conditions and in response to disease. The expression of Runx1 is regulated at the transcriptional level by two promoters designated P1 and P2. Alternative usage of these two promoters creates differential mRNA transcripts diversified in distribution and translational potential. While the significance of P1/P2 promoter-switch in the transcriptional control of Runx1 has been highlighted in the embryogenic process, very little is known about the level of P1- and P2-specific transcripts in adult hearts, and the underlying mechanisms controlling the promoter-switch.
To amplify P1/P2 specific sequences in the heart, we used two different sense primers complementary to either P1 or P2 5'-regions to monitor the expression of P1/P2 transcripts. DNA methylation levels were assessed at the Runx1 promoter regions. Rats were grouped by age.
The expression levels of both P1- and P2-derived Runx1 transcripts were decreased in older rats when compared with that in young adults, paralleled with an age-dependent decline in Runx1 protein level. Furthermore, older rats demonstrated a higher degree of DNA methylation at Runx1 promoter regions. Alternative promoter usage was observed in hearts with increased age, as reflected by altered P1:P2 mRNA ratio.
Our data demonstrate that the expression of Runx1 in the heart is age-dependent and underscore the importance of gene methylation in the promoter-mediated transcriptional control of Runx1, thereby providing new insights to the role of epigenetic regulation in the heart.
runt 相关转录因子 1（RUNX1）是核心结合因子家族转录因子的关键成员，它已成为心血管疾病的新的治疗靶点。充分了解 RUNX1 在心脏中的表达模式以及在正常条件下和响应疾病时其受调控的机制非常重要。RUNX1 的表达受两个指定为 P1 和 P2 的启动子在转录水平上调控。这两个启动子的选择性使用会产生在分布和翻译潜力方面多样化的差异 mRNA 转录物。虽然 P1/P2 启动子转换在 RUNX1 的转录控制中的意义在胚胎发生过程中已得到强调，但对于成年心脏中 P1 和 P2 特异性转录物的水平及其潜在的启动子转换调控机制知之甚少。
为了在心脏中扩增 P1/P2 特异性序列，我们使用了两个互补于 P1 或 P2 5'-区域的不同有义引物来监测 P1/P2 转录物的表达。评估了 RUNX1 启动子区域的 DNA 甲基化水平。根据年龄将大鼠分组。
与年轻成年人相比，老年大鼠的 P1-和 P2 衍生的 RUNX1 转录物的表达水平降低，同时 RUNX1 蛋白水平也随年龄的增长而下降。此外，在 RUNX1 启动子区域，老年大鼠表现出更高程度的 DNA 甲基化。随着年龄的增长，观察到心脏中的替代启动子使用，如改变的 P1：P2 mRNA 比值所反映的那样。
我们的数据表明，心脏中 RUNX1 的表达随年龄而变化，并强调了基因甲基化在 RUNX1 启动子介导的转录控制中的重要性，从而为表观遗传调控在心脏中的作用提供了新的见解。
