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。时空上的机制 心肌细胞中的细胞内协调信号仍然不清楚。而磷酸化在心脏中的作用 信号转导已经研究了几十年，对脂质调节信号转导知之甚少。 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结合 由ZDHHC S酰基转移酶催化。S-酰化是一种调节动态缔合的最佳机制 在特定的膜结构域上具有信号复合体和受体的蛋白质。细胞因子受体通过 Janus Kinase(JAK)-信号转导和转录激活因子(Stat)途径整合炎症反应 以及在心脏应激期间的促纤维化信号和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 和其他免疫细胞渗入心脏并分泌促炎细胞因子激活Jak-Stat 在心肌细胞中的通路，当延长时，大大有助于不利的心脏重塑， 加速了疾病的发病机制。值得注意的是，无偏见的蛋白质组学确定JAK1是具有最多 心肌细胞特异性高尔基酶过表达小鼠心脏S酰化增强， ZDHHC9.过度表达zDHHC9的转基因小鼠继续发展为心肌肥厚，进展为 功能失代偿和衰竭，但这种表型之前有增强的JAK1 S酰化和 STAT3的磷酸化和核转位，提示zDHHC9激活促肥大的JAK1/STAT3 活体心肌细胞内的信号转导。这一提议将检验中央假说，即ZDHHC9调控的S- JAK1的酰化促进其向细胞因子受体的顺行转运，STAT3被细胞因子激活 刺激，从而导致心脏重塑、心肌炎和心力衰竭 进步。在本应用程序中，我们将在压力的背景下操作zDHHC9和JAK1的S酰化反应 超负荷诱导心肌肥厚以达到以下目的：(1)测定zDHHC9在心肌细胞中的功能。 心肌细胞Jak-Stat信号、肥大和不良重构的调控及(2)机制 JAK1 S酰化在细胞因子受体信号转导中的作用 我们将确定zDHHC9和JAK1 S酰化对JAK1蛋白运输和稳定性的作用，STAT3 激活和转录程序，并将这些信号输出的动力学与病理生理联系起来 心脏炎症、纤维化、心肌细胞肥大和凋亡，促进不利的重塑和 向心力衰竭的过渡。这些研究将建立调控S-酰化作为一种机制的范式 控制心肌细胞细胞因子受体信号的持续时间和幅度并识别适应不良 细胞内信号机制可能为心脏病的治疗提供新的靶点。

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.