The ER Stress-Induced Selenoprotein, SelenoS, Regulates Proteostasis and Cardiac Hypertrophy

项目摘要 许多形式的心血管疾病会导致病理性心肌肥大，这是不适应的，因为 它会导致心脏收缩能力降低，导致危及生命的心力衰竭。相比之下，锻炼可以 使心脏以一种适应功能的方式生长；这被定义为生理性心肌肥大。我们的 长期目标是从机制上更好地理解心脏发育的两种形式。在这份提案中， 我们将通过研究硒(Se)在心肌肥厚中的作用来解决这个问题。Se，这是 我们饮食中的一个基本元素，众所周知是心血管健康所必需的，尽管它的确切作用是 由Se扮演的心血管系统尚不清楚。硒在所有器官和细胞中的主要作用是它是一种 硒蛋白的关键成分；在这里，我们将研究硒在心脏硒蛋白中的功能。我们的 特定的目标是检测硒蛋白，我们认为这是两者所必需的 病理性和生理性心肌肥厚。我们将在小鼠模型中进行这项研究 利用分子遗传学方法选择性和特异性地损害或增强心肌肥厚 SelenoS的功能，随后进行研究，以确定这些动作对心脏结构和 功能。我们将解决的一个机制问题是硒如何影响心脏发育。然而，由于有 小鼠体内需要Se的其他23种蛋白质，以便我们的方法集中在确定Se如何被 在心脏中，我们将检查SelenoS的突变形式--SelenoS-Se的影响，这是不同的 来自SelenoS的唯一原因是它不含Se。通过这种方式，我们将能够机械地精确定位 仅在SelenoS上工作以支持心脏生长，因为所有其他硒蛋白仍将具有Se 整合到它们的结构中。SelenoS还参与了错误折叠的蛋白质在 内质网，这一过程被称为ERAD。我们还将研究SelenoS，SelenoS-Se， 以及一种不能在ERAD中发挥作用的SelenoS，即Seleno-ERAD，促进心脏生长。我们的具体目标是 1-测定耗竭内源性硒对心脏结构、功能、基因和蛋白的影响 在小鼠心肌肥厚模型中的表达，2-检测SelenoS的异位表达的影响， 内源性SelenoS在病理上被击倒的小鼠的Seleno-ERAD和SelenoS-Se 和生理性心肌肥厚，以及3-评估SelenoS、Seleno-ERAD和SelenoS-Se如何影响 ERAD复合体的结构和功能。

Project Summary Many forms of cardiovascular disease lead to pathological cardiac hypertrophy, which is maladaptive because it causes reduced contractility of the heart, resulting in life-threatening heart failure. In contrast, exercise can cause the heart to grow in a functionally adaptive way; this is defined as physiological cardiac hypertrophy. Our long-term goal is to achieve a better mechanistic understanding of both forms of heart growth. In this proposal, we will address this understanding by examining roles for selenium (Se) in cardiac hypertrophy. Se, which is an essential element in our diet, is well known to be required for cardiovascular health, though the precise role played by Se the cardiovascular system is not known. A major role for Se in all organs and cells is that it is a key component of selenoproteins; here, we will examine the function of Se in selenoproteins in the heart. Our specific objective is to examine the selenoprotein, SelenoS, which we believe to be required for both pathological and physiological cardiac hypertrophy. We will conduct this investigation in mouse models of cardiac hypertrophy using molecular genetic approaches to selectively and specifically impair or enhance the function of SelenoS, followed by studies to determine the effects of these maneuvers on heart structure and function. One mechanistic point we will be addressing is how Se affects heart growth. However, since there are 23 other proteins in mice that require Se, in order to focus our approach on determining how Se is used by only SelenoS in the heart, we will examine the effects of a mutant form of SelenoS, SelenoS-Se, which is different from SelenoS only in that it does not have Se. In this way, we will be able to mechanistically pinpoint how Se on just SelenoS works to support cardiac growth, because all of the other selenoproteins will still have Se incorporated into their structures. SelenoS is also involved in the adaptive degradation of misfolded proteins in the endoplasmic reticulum, a process called ERAD. We will also examine the effects of SelenoS, SelenoS-Se, and a form of SelenoS that cannot function in ERAD, Seleno-ERAD, on cardiac growth. Our specific aims are to 1- determine the effects of depleting endogenous SelenoS on cardiac structure, function, gene and protein expression in mouse models of cardiac hypertrophy, 2- examine the effects of ectopic expression of SelenoS, Seleno-ERAD and SelenoS-Se in mice in which endogenous SelenoS has been knocked down on pathological and physiological cardiac hypertrophy, and 3- assess how SelenoS, Seleno-ERAD and SelenoS-Se affect the structure and function of the ERAD complex.