Regulation of TRAF2-Dependent Inflammatory Signaling by Small Proline Rich Protein 1A in the Myocardium

摘要： 心力衰竭（HF）是全球死亡的主要原因，其定义为心脏无法充分泵血 血液遍布全身。HF可由持续性疾病（如高血压）或急性 如心肌梗死（MI）。心肌梗死的特征是冠状血管阻塞 导致局部缺血。心肌细胞（CM）受缺血影响发生坏死和凋亡。清除 所产生的细胞碎片、免疫细胞浸润该区域，而驻留的成纤维细胞开始分泌一 细胞外基质丰富的疤痕，以维持心脏的结构完整性。这一雄辩的回应至关重要 以克服最初的伤害，任何特定阶段的夸大都可能产生有害影响。而 高血压和心肌梗死相关疾病的病因是独特的，它们具有相似的特征， 肥大、炎症和纤维化。为了更好地了解病理性心脏重塑的过程， 我们进行了RNA测序，以确定与病理相关的转录基因表达谱， 命运我们鉴定了一个富含脯氨酸的小蛋白（SPRRs）家族，它们在疾病中受到不同的调控; Sprr 1a在边缘区（BZ）的CF和CM中响应于炎性细胞因子而高度上调， MI.初步数据表明SPRR 1A和肿瘤坏死因子（TNF）之间的预测结合位点 受体相关因子（TRAF）2，一种E3泛素连接酶，在肿瘤坏死因子受体的作用下， 质膜传播炎症信号。进一步的调查使我们推测， SPRR 1A正在改变CM中的泛素化状态或蛋白酶体功能，以阻止促炎信号传导 并允许炎症消退途径的增加。分别地，SPRR 1A和TRAF 2可以 也在损伤边缘沿着的细胞存活率中发挥作用。了解协调的 MI后的愈合反应将为进一步的治疗发展奠定基础。这项建议 目的是确定新的体外作用机制和相关的体内并发症， SPRR 1A表达的调节。

ABSTRACT: Heart failure (HF) is a leading cause of death worldwide and defined by an inability of the heart to pump sufficient blood throughout the body. HF can be induced by persistent conditions such as high blood pressure, or by acute injuries such as myocardial infarction (MI). MI is characterized by the obstruction of a coronary blood vessel resulting in ischemia. Cardiomyocytes (CMs) affected by the ischemia undergo necrosis and apoptosis. To clear the resulting cellular debris, immune cells infiltrate the area while resident fibroblasts begin to secrete an extracellular matrix-rich scar to maintain the structural integrity of the heart. This eloquent response is essential to overcoming the initial injury, and exaggeration of any particular phase can have detrimental effects. While the etiology of disease associated with high blood pressure and MI are unique, they share similar features such as hypertrophy, inflammation, and fibrosis. To better understand the process of pathological cardiac remodeling, we performed RNA-sequencing to identify transcriptional gene expression profiles associated with pathologic fates. We identified a family of small proline-rich proteins (SPRRs) that are differentially regulated in disease; Sprr1a is highly upregulated in response to inflammatory cytokines in CFs and CMs in the border zone (BZ) after MI. Preliminary data suggests a predicted binding site between SPRR1A and tumor necrosis factor (TNF) receptor associated factor (TRAF)2, an E3 ubiquitin ligase that acts in response to the TNF receptor at the plasma membrane to propagate inflammatory signaling. Further investigation has led us to hypothesize that SPRR1A is altering the ubiquitination status or proteasome function in CMs to halt pro-inflammatory signaling and allow for the increase in inflammation-resolution pathways to occur. Separately, SPRR1A and TRAF2 may also be playing a role in the rate of cell survival along the border of injury. Understanding the coordination of the healing response following MI will build the basis needed for further therapeutic developments. This proposal aims to determine the novel in vitro mechanism of action and associated in vivo complications associated with the modulation of SPRR1A expression.