Regulation of Vascular Smooth Muscle Cell Phenotype by a Novel Isoform of Glucose-6-Phosphate Dehydrogenase

血管疾病仍然是美国和世界范围内的主要死亡原因。有人提出，新陈代谢 重新编程和葡萄糖-6-磷酸脱氢酶(G6PD)活性和表达的增加有助于 致命性血管增生性血管病变的发病机制。此外，一些研究表明，个人失去- 功能G6PD(地中海或非洲)变体-S188F(G6PDS188F；A型；严重缺乏症)或N126D (G6PDN126D；A型；轻度缺乏症)非同义单核苷酸多态-有较低的频率 冠状动脉疾病。然而，G6PD驱动的致病和G6PD变体相关的保护机制 影响血管疾病的因素仍然难以捉摸。因此，我们建议确定潜在的机制，由一种新的 在血管平滑肌细胞(VSMCs)的细胞核中发现了G6PD亚型，这些亚型与致病大 动脉僵硬和重塑。基于有力支持的初步结果，我们假设核G6PD 是表观遗传修饰物的调节者，也是VSMC的转录调节因子。因此，功能丧失 G6PD(S188F，N126D)变异阻断了表观基因组的不适应性修饰，降低了大动脉弹性和 肥胖/代谢综合征和球囊损伤引起的重构。我们将从三个具体的方面来检验这一假设 目标。在目标1中，我们将检验这样的假设，即细胞核中的G6PD和/或G6PD协调的氧化还原控制着 表观遗传修饰因子(DNA甲基转移酶(DNMT)、DNA(Tet)和组蛋白)的表达和活性 (贾里德脱甲基酶)和编码参与调节分化的蛋白质的基因转录 (收缩)和去分化(促炎症、血栓形成和增殖)表型。在目标2中， 我们将确定功能丧失的G6PD变体是否从表观遗传修饰物中分离出来以增加DNA 甲基化，抑制组蛋白3-赖氨酸4的三甲基化，并减少导致适应不良的基因的转录(促进 炎性、血栓形成和增殖)。在目标3中，我们将确定G6PD变异 大鼠表现出较少的不适应性表观遗传学改变(组蛋白3-赖氨酸4三甲基化)，并形成较少的大动脉 与饲喂高脂饮食(肥胖/代谢模型)的野生型大鼠相比，弹性(僵硬)和血管重塑 综合征)或颈动脉球囊损伤。功能获得和功能丧失研究的结果 将揭示G6PD对致病血管重塑相关基因表达的直接影响 和大动脉僵硬，导致心力衰竭和死亡。我们预计将对血管生物学产生两个重大影响： [1]迄今未知的G6PD依赖的亚细胞氧化还原直接与基础 血管病理生物学中的转录机制和基因转录以及新治疗方法的开发 靶向氧化还原信号以减少大动脉僵硬和重塑。

Vascular diseases continue to be a major cause of death in the US and worldwide. It has been proposed that metabolic reprogramming and increased glucose-6-phosphate dehydrogenase (G6PD) activity and expression contribute to the pathogenesis of fatal angioproliferative vasculopathies. Moreover, some studies suggest individuals with a loss-of- function G6PD (Mediterranean or African) variant – S188F (G6PDS188F; Type A-; severe deficiency) or N126D (G6PDN126D; Type A; mild deficiency) nonsynonymous single nucleotide polymorphism – have lower frequencies of coronary artery disease. However, G6PD-driven pathogenic and G6PD variant-associated protective mechanisms affecting vascular diseases remain elusive. We therefore propose to determine potential mechanisms, driven by a newly discovered G6PD isoform in the nucleus of vascular smooth muscle cells (VSMCs), that contribute to pathogenic large artery stiffness and remodeling. Based on strongly supporting preliminary results, we hypothesized that nuclear G6PD is a modulator of epigenetic modifiers and is a transcription regulator in VSMCs. Consequently, the loss-of-function G6PD (S188F, N126D) variants block maladaptive modifications of the epigenome, reducing large artery elastance and remodeling elicited by obesity/metabolic syndrome and balloon-injury. We will test this hypothesis in three specific aims. In Aim 1, we will test the hypothesis that G6PD and/or G6PD-coordinated redox in the nucleus controls the expression and activity of epigenetic modifiers (DNA methyltransferases (DNMT) and DNA (TET) and histone (JARID) demethylases) and transcription of genes that encode proteins involved in regulating the differentiation (contractile) and dedifferentiation (pro-inflammatory, -thrombotic, and -proliferative) phenotypes in VSMCs. In Aim 2, we will determine whether loss-of-function G6PD variants detach from epigenetic modifiers to increase DNA methylation, suppress histone3-lysine4 trimethylation, and reduce transcription of genes that confer maladaptive (pro- inflammatory, -thrombotic, and -proliferative) properties to VSMCs. In Aim 3, we will determine whether G6PD variant rats express fewer maladaptive epigenetic (histone3-lysine4 trimethylation) changes and develop less large artery elastance (stiffness) and vascular remodeling than wild-type rats fed a high-fat diet (a model of obesity/metabolic syndrome) or subjected to carotid artery balloon-injury. The results from gain-of-function and loss-of-function studies of this project will reveal the direct effect of G6PD on gene expression associated with pathogenic vascular remodeling and large artery stiffness, which lead to heart failure and death. We foresee two significant impacts on vascular biology: [1] linkage of heretofore unknown G6PD-dependent subcellular redox in the nucleus directly to the fundamental transcriptional mechanics and gene transcription in vascular pathobiology and [2] development of new treatments targeting redox signaling to reduce large artery stiffness and remodeling.