Fletcher ELizabeth K, Kanki Monica, Morgan James, Ray David W, Delbridge Lea, Fuller Peter James, Clyne Colin D, Young Morag J
E Fletcher, Sackler School of Graduate Biomedical Sciences, Tuft Medical Centre, Boston, United States.
M Kanki, Centre for Endocrinology and Metabolism, Hudson Institute of Medical Research, Melbourne, Australia.
J Endocrinol. 2019 Jan 1. doi: 10.1530/JOE-18-0584.
We previously identified a critical pathogenic role for MR activation in cardiomyocytes that included a potential interaction between the MR and the molecular circadian clock. While glucocorticoid regulation of the circadian clock is undisputed, MR interactions with circadian clock signalling are limited. We hypothesised that the MR influences cardiac circadian clock signalling, and vice versa. 10nM aldosterone or corticosterone regulated CRY 1, PER1, PER2 and ReverbA (NR1D1) gene expression patterns in H9c2 cells over 24hr. MR-dependent regulation of circadian gene promoters containing GREs and E-box sequences was established for CLOCK, Bmal, CRY 1 and CRY2, PER1 and PER2 and transcriptional activators CLOCK and Bmal modulated MR-dependent transcription of a subset of these promoters. We also demonstrated differential regulation of MR target gene expression in hearts of mice 4hr after administration of aldosterone at 8AM versus 8PM. Our data support combined MR regulation of a subset of circadian genes and that endogenous circadian transcription factors CLOCK and Bmal modulate this response. This unsuspected relationship links MR in the heart to circadian rhythmicity at the molecular level and has important implications for the biology of MR signalling in response to aldosterone as well as cortisol. These data are consistent with MR signalling in the brain where, like the heart, it preferentially responds to cortisol. Given the undisputed requirement for diurnal cortisol release in the entrainment of peripheral clocks, the present study highlights the MR as an important mechanism for transducing the circadian actions of cortisol in addition to the GR in the heart.
我们之前确定了心肌细胞中MR激活的关键致病作用，其中包括MR与分子生物钟之间的潜在相互作用。虽然糖皮质激素对生物钟的调节是无可争议的，但MR与生物钟信号传导的相互作用却很有限。我们假设MR影响心脏生物钟信号传导，反之亦然。10nM醛固酮或皮质酮在24小时内调节H9c2细胞中CRY 1、PER1、PER2和Rev-erbA（NR1D1）基因的表达模式。对于包含GRE和E-box序列的生物钟基因启动子，建立了MR依赖性调节，涉及CLOCK、Bmal、CRY 1和CRY2、PER1和PER2，并且转录激活因子CLOCK和Bmal调节了这些启动子中一部分的MR依赖性转录。我们还证明，上午8点与晚上8点给予醛固酮4小时后，小鼠心脏中MR靶基因表达存在差异调节。我们的数据支持MR对一部分生物钟基因的联合调节，并且内源性生物钟转录因子CLOCK和Bmal调节这种反应。这种未被怀疑的关系在分子水平上将心脏中的MR与昼夜节律联系起来，并且对MR信号传导响应醛固酮以及皮质醇的生物学具有重要意义。这些数据与大脑中的MR信号传导一致，在大脑中，与心脏一样，它优先对皮质醇作出反应。鉴于在外周生物钟的同步中昼夜皮质醇释放的无可争议的必要性，本研究强调MR是除心脏中的GR之外转导皮质醇昼夜作用的重要机制。
