S-acylation-dependent regulation of cytokine receptor signaling and cardiac maladaptation

项目摘要 心脏病是美国和世界范围内的主要死亡原因。时空机制 协调心肌细胞内信号传导仍然不清楚。虽然磷酸化在心脏中的作用 信号转导已经研究了几十年，但是关于脂质对信号转导的调节知之甚少 修改.半胱氨酸棕榈酰化或S-酰化是脂肪酸与蛋白质的可逆连接 由zDHHC S-酰基转移酶催化。S-酰化是调节蛋白质与蛋白质之间动态结合的最佳机制。 在特定膜结构域具有信号复合物和受体的蛋白质。细胞因子受体通过 Janus激酶（Jak）-信号转导子和转录激活子（Stat）途径整合炎症 和促纤维化信号，并在心脏应激期间介导炎性基因表达程序，例如 对压力过载的反应。巨噬细胞对病理性刺激、缺血性损伤或感染的反应， 和其他免疫细胞浸润心脏，分泌促炎细胞因子，激活Jak-Stat 心肌细胞中的信号通路，当延长时，其实质上有助于不利的心脏重塑， 加速疾病的发病。引人注目的是，无偏见的蛋白质组学将Jak 1确定为具有最多 心肌细胞特异性过表达高尔基体酶的小鼠心脏中S-酰化增加， zDHHC 9.过表达zDHHC 9的转基因小鼠继续发展心脏肥大， 功能性失代偿和衰竭，但这种表型之前是增强的Jak 1 S-酰化， 磷酸化和Stat 3的核转位，表明zDHHC 9激活促肥大性Jak 1/Stat 3 体内心肌细胞中的信号传导。该提案将检验zDHHC 9调节S- Jak 1的酰化促进其向细胞因子受体的顺行运输，Stat 3响应于细胞因子的活化 刺激，从而导致适应不良的心脏重塑、心肌炎症和心力衰竭 进展在该应用中，我们将在压力的背景下操纵zDHHC 9和Jak 1 S-酰化 超负荷诱导的心肌肥大，以实现以下目的：（1）确定zDHHC 9在心肌细胞中的功能。 调节心肌细胞Jak-Stat信号传导，肥大和不良重塑，和（2）描绘机制 Jak 1 S-酰化在心肌肥厚和心力衰竭发病过程中细胞因子受体信号传导中的作用。 我们将确定zDHHC 9和Jak 1 S-酰化对Jak 1蛋白运输和稳定性、Stat 3 激活和转录程序，并将这些信号输出的动力学与病理生理 心脏炎症、纤维化和心肌细胞肥大和凋亡，这些都会促进不良重塑， 向心力衰竭的转变这些研究将为调节S-酰化作为一种机制建立一个范例 控制心肌细胞细胞因子受体信号传导的持续时间和幅度， 细胞内信号传导机制，可能为心脏病的治疗提供新的目标。

Project Summary Heart disease is the leading cause of death in the United States and worldwide. Mechanisms that spatiotemporally coordinate intracellular signaling in cardiomyocytes remain ill-defined. While the roles of phosphorylation in cardiac signal transduction have been studied for decades, very little is known regarding regulation of signaling by lipid modifications. Cysteine palmitoylation or S-acylation is the reversible attachment of fatty acids onto proteins catalyzed by zDHHC S-acyl transferases. S-acylation is an optimal mechanism to regulate dynamic association of proteins with signaling complexes and receptors at specified membrane domains. Cytokine receptors signal through the Janus kinase (Jak)-Signal transducer and activator of transcription (Stat) pathway to integrate inflammatory and profibrotic signals and mediate inflammatory gene expression programs during cardiac stress, such as the response to pressure overload. In response to pathological stimulation, ischemic injury, or infection, macrophages and other immune cells infiltrate the heart and secrete pro-inflammatory cytokines that activate the Jak-Stat pathway in cardiac myocytes, which when prolonged contributes substantially to adverse cardiac remodeling that hastens disease pathogenesis. Strikingly, unbiased proteomics identified Jak1 as the protein with the most increased S-acylation in hearts of mice with cardiomyocyte-specific overexpression of the Golgi enzyme, zDHHC9. Transgenic mice overexpressing zDHHC9 go on to develop cardiac hypertrophy that progresses to functional decompensation and failure, but this phenotype is preceded by enhanced Jak1 S-acylation and phosphorylation and nuclear translocation of Stat3, suggesting zDHHC9 activates prohypertrophic Jak1/Stat3 signaling in cardiac myocytes in vivo. This proposal will test the central hypothesis that zDHHC9-regulated S- acylation of Jak1 promotes its anterograde trafficking to cytokine receptors, Stat3 activation in response to cytokine stimulation, and consequently maladaptive cardiac remodeling, myocardial inflammation, and heart failure progression. In this application we will manipulate zDHHC9 and Jak1 S-acylation in the context of pressure overload-induced cardiac hypertrophy to achieve the following aims: (1) determine functions of zDHHC9 in the regulation of cardiomyocyte Jak-Stat signaling, hypertrophy and adverse remodeling, and (2) delineate mechanistic roles of Jak1 S-acylation in cytokine receptor signaling during the pathogenesis of cardiac hypertrophy and failure. We will ascertain functions of zDHHC9 and Jak1 S-acylation on Jak1 protein trafficking and stability, Stat3 activation and transcriptional programs, and correlate the kinetics of these signaling outputs with pathophysiologic cardiac inflammation, fibrosis, and cardiomyocyte hypertrophy and apoptosis that promote adverse remodeling and the transition to heart failure. These studies will establish a paradigm for regulated S-acylation as a mechanism governing the duration and amplitude of cardiomyocyte cytokine receptor signaling and identify maladaptive intracellular signaling mechanisms that may provide novel targets for the treatment of heart disease.