Non-canonical ERAD as a Regulator of Cardiac Hypertrophy

非典型 ERAD 作为心脏肥大的调节剂

基本信息

批准号：
10363838
负责人：
Chris Glembotski
金额：
$ 61.5万
依托单位：
UNIVERSITY OF ARIZONA
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-01-01 至 2025-12-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10363838
关键词：
Address Aldosterone Amino Acids Binding Binding Proteins Calcium Cardiac Cardiac Myocytes Cardiovascular Diseases Catalytic Domain Cessation of life Data Ectopic Expression Endoplasmic Reticulum Ensure Epithelial Cells Equilibrium Glucocorticoids Growth Heart Heart Diseases Heart Hypertrophy Heart failure Human Hypertrophy Interruption Kidney Knowledge Left Leucine Zippers Link Masks Mediating Methods Molecular Mus Muscle Cells Neonatal Pathologic Pathology Peptides Phosphotransferases Physiologic intraventricular pressure Plasma Protein Biosynthesis Protein Overexpression Proteins Proteome Rattus Role Serum Serum Proteins Sgk protein Side Signal Transduction Site Study of serum System Therapeutic Ventricular base cancer cell cell type endoplasmic reticulum stress heart function innovation knock-down misfolded protein mortality multicatalytic endopeptidase complex novel overexpression pressure protein degradation protein folding proteostasis receptor renal epithelium response ubiquitin-protein ligase

项目摘要

PROJECT SUMMARY Increases in protein synthesis during pathological cardiac hypertrophy places demands on protein-folding machinery to avert the accumulation of toxic misfolded proteins. Associated with the endoplasmic reticulum (ER), where many important proteins are synthesized in cardiac myocytes, is a system that recognizes and degrades misfolded proteins, i.e. ER associated (protein) degradation, or ERAD. We discovered a different, non-canonical role for ERAD as a regulator of the levels of the growth-promoting kinase, serum glucocorticoid kinase 1 (SGK1). SGK1 is a cytosolic kinase involved in growth of other cell types, such as cancer cells. Interestingly, SGK1 can traffic to the ER where it is ubiquitylated by ERAD machinery and subsequently degraded by cytosolic proteasomes; however, this unique regulatory mechanism has not been studied in the heart. Our preliminary evidence shows that non-canonical ERAD could regulate SGK1 levels in the heart and, thereby regulating cardiac growth under pathological conditions. We also found that an SGK1-binding protein, called glucocorticoid-inducible leucine zipper protein (GILZ), can bind to and protect SGK1 from non-canonical ERAD-mediated degradation, which we believe increases SGK1-mediated growth of the heart during pressure overload. Accordingly, our hypothesis is that SGK1 is a major inducer of pressure overload-induced cardiac pathology. During pressure overload, SGK1 levels, and thus, SGK1-mediated cardiac hypertrophy and subsequent pathology, are increased by GILZ-dependent diversion of SGK1 away from the ER, which decreases SGK1 degradation by non-canonical ERAD. Ectopic expression of an SGK1 peptide disrupts the GILZ-SGK1 interaction, increases SGK1 degradation, thus decreasing SGK1-mediated cardiac hypertrophy and subsequent pathology. This hypothesis will be examined in mice subjected to pressure overload-induced cardiac pathology in our specific aims, which are to 1-couple cardiac-specific SGK1 deletion with AAV9 encoding SGK1-WT (active; ER-targeted), SGK1-KD (kinase-dead ER-targeted) or SGK1-∆60 (active; not ER-targeted) to examine the effect of SGK1 and ERAD on overload-induced cardiac pathology, 2-combine AAV9-SGK1-WT or AAV9- SGK1-∆60 with AAV9-mediated GILZ overexpression or knockdown to determine whether GILZ diverts SGK1- WT from the ER and protects it from ERAD in the heart, 3-evaluate the potential therapeutic, antihypertrophic effects of a novel SGK1 peptide that interrupts GILZ-SGK1 binding, and increases non-canonical ERAD- mediated SGK1 degradation. These studies are significant because they will reveal previously unappreciated roles for SGK1, GILZ and ERAD in pathologic cardiac hypertrophy. We will use an innovative molecular strategy to mechanistically dissect roles for GILZ and non-canonical ERAD as regulators of SGK1 signaling and cardiac pathology. Peptide-based disruption of the SGK1-GILZ interaction could be a highly specific method for inhibiting the maladaptive pathological effects of SGK1 in the heart by selective degradation of SGK1.

项目概要病理性心脏肥大期间蛋白质合成的增加对蛋白质折叠提出了要求避免与内质网相关的有毒错误折叠蛋白质积累的机制。 (ER) 是心肌细胞中合成许多重要蛋白质的系统，它能够识别和降解错误折叠的蛋白质，即 ER 相关（蛋白质）降解，或 ERAD。 ERAD 作为促生长激酶、血清糖皮质激素水平调节剂的非典型作用激酶 1 (SGK1) 是一种参与其他细胞类型（例如癌细胞）生长的胞质激酶。暗示，SGK1 可以运输到 ER，在那里它被 ERAD 机器普遍化，随后被胞质蛋白酶体降解；然而，这种独特的调节机制尚未得到研究。我们的初步证据表明，非典型 ERAD 可以调节心脏中的 SGK1 水平，并且，我们还发现 SGK1 结合蛋白在病理条件下调节心脏生长。称为糖皮质激素诱导的亮氨酸拉链蛋白 (GILZ)，可以结合 SGK1 并保护其免受非规范影响 ERAD 介导的降解，我们认为这会增加压力期间 SGK1 介导的心脏生长因此，我们的假设是 SGK1 是压力超负荷引起的心脏的主要诱因。在压力超负荷期间，SGK1 水平升高，从而导致 SGK1 介导的心脏肥大和随后的病理学，通过 GILZ 依赖的 SGK1 远离 ER 的转移而增加，从而减少 SGK1 肽的非典型 ERAD 降解会破坏 GILZ-SGK1。相互作用，增加 SGK1 降解，从而减少 SGK1 介导的心脏肥大和随后的心脏肥大该假设将在承受压力超负荷引起的心脏病理学的小鼠中进行检验。我们的具体目标是将心脏特异性 SGK1 缺失与编码 SGK1-WT 的 AAV9 配对（活性；ER 靶向）、SGK1-KD（激酶死亡 ER 靶向）或 SGK1-Δ60（活性；非 ER 靶向）进行检查 SGK1和ERAD对过载诱发的心脏病理学的影响，2-组合AAV9-SGK1-WT或AAV9- SGK1-Δ60与AAV9介导的GILZ过表达或敲低以确定GILZ是否转移SGK1- 来自 ER 的 WT 并保护其免受心脏 ERAD 的影响，3-评估潜在的治疗、抗肥厚一种新型 SGK1 肽的作用，它会中断 GILZ-SGK1 结合，并增加非典型 ERAD- 这些研究很重要，因为它们将揭示以前未被认识到的。我们将使用创新的分子策略来研究 SGK1、GILZ 和 ERAD 在病理性心脏肥大中的作用。机械地剖析 GILZ 和非规范 ERAD 作为 SGK1 信号传导和心脏调节剂的作用基于肽的 SGK1-GILZ 相互作用破坏可能是一种高度特异性的抑制方法。通过 SGK1 的选择性降解，SGK1 在心脏中产生适应不良的病理效应。