Smyd1's role in regulating disease-induced remodeling and gene expression in the cardiomyocyte

项目摘要 心力衰竭是发达国家的主要死亡原因，其特点是心肌细胞生长， 纤维化和器官重塑，并伴随着心肌细胞基因组的转录变化。这些 构成适应性和非适应性重新编程的基因表达的全球变化是受驱动的 通过染色质的结构变化。尽管许多表观遗传因素已被确定为影响这些 转录变化，负责调节染色质的蛋白质及其随后对 心脏病期间的细胞和器官重塑在很大程度上是未知的。需要改变的一个关键机制 染色质的结构是通过组蛋白修饰和利用组蛋白脱乙酰酶抑制剂进行的早期研究 研究表明，在动物模型中进行治疗可以减缓心脏病的进展，尽管 这些蛋白质的无处不在的表达和抑制剂的非特异性使得它们不可行 作为心脏的治疗工具，到目前为止。相反，Smyd1是一种独特的肌细胞特异性组蛋白 在心肌细胞中调节基因表达的甲基转移酶。它最初被证明在 心脏早期发育，然而最近，我们已经确定Smyd1是差异调节的 在人类心力衰竭患者和心脏病的小鼠模型中。此外，我们已经证明了 成年小鼠心脏中Smyd1的缺失导致促肥大信号转导导致心肌细胞生长、纤维化 和功能衰退。此外，我们还检测了两种Smyd1亚型，Smyd1a和Smyd1b 结果表明，Smyd1a过表达能够抑制苯肾上腺素诱导的心肌细胞增殖 肥大。在这项工作的基础上，我将(目标1)确定Smyd1a在心脏中的过度表达是否能够 使用新的转基因小鼠模型抑制疾病诱导的重塑，以及(目标2)确定特定的 基因组中被Smyd1修饰的基因通过染色质调节心肌肥大信号 免疫沉淀和下一代DNA测序(CHIP-SEQ)。这项提议将使我能够 确定Smyd1在成人心脏中的功能，评估其在减轻心脏病中的作用，并确定 调控心肌细胞生长的分子机制。总体而言，这些实验将增强我们的 了解染色质重塑的全球变化是如何协调的，以及它们如何影响心脏 心脏病发生发展过程中的表型。

Project Summary Heart failure is the leading cause of death in developed countries and is characterized by myocyte growth, fibrosis and organ remodeling, and is accompanied by transcriptional changes in the myocyte genome. These global changes in gene expression, which constitute both adaptive and maladaptive reprogramming, are driven by structural changes in chromatin. Although many epigenetic factors have been identified that influence these transcriptional changes, the proteins responsible for regulating chromatin and their subsequent effects on cellular and organ remodeling during heart disease are largely unknown. One key mechanism to alter chromatin structure is through histone modifications and early studies utilizing histone deacetylase inhibitors revealed that heart disease progression could be attenuated upon treatment in animal models, although the ubiquitous expression of these proteins and the non-specific nature of the inhibitors has made them unfeasible as a therapeutic tool in the heart, thus far. In contrast, Smyd1, is a unique myocyte-specific histone methyltransferase that regulates gene expression in the cardiomyocyte. It was originally shown to play a role in early cardiac development, however more recently, we have determined that Smyd1 is differentially regulated in human heart failure patients and in mouse models of heart disease. In addition, we have demonstrated that loss of Smyd1 in the adult mouse heart leads to pro-hypertrophic signaling resulting in myocyte growth, fibrosis and functional decline. Additionally, we examined the two Smyd1 isoforms, Smyd1a and Smyd1b, in isolated myocytes and showed that Smyd1a overexpression was capable of inhibiting phenylephrine-induced hypertrophy. To build upon this work I will (Aim 1) determine if overexpression of Smyd1a in the heart is able to inhibit disease-induced remodeling using a novel transgenic mouse model, and (Aim 2) identify the specific genes modified by Smyd1 in the genome to regulate hypertrophic signaling in the myocardium using chromatin immunoprecipitation and next-generation DNA sequencing (ChIP-Seq). This proposal will allow me to determine the function of Smyd1 in the adult heart, evaluate its role in attenuating heart disease and identify the molecular mechanisms by which myocyte growth is regulated. Overall these experiments will enhance our understanding of how global changes in chromatin remodeling are coordinated and how they affect cardiac phenotype during the development of heart disease.