Role of Arginase 1 in Retinal Ischemia Reperfusion Injury

家长拨款摘要R00EY029373： 视网膜缺血是常见视网膜疾病导致视力丧失的主要原因，包括 糖尿病视网膜病变、青光眼、早产儿视网膜病变、静脉阻塞。这个项目的目的是 明确视网膜缺血性损伤的机制，寻找新的治疗靶点。 我们之前已经证明了精氨酸酶与视网膜的关系。 神经血管疾病。精氨酸酶有两种亚型。根据实验室的发现， 线粒体亚型精氨酸酶2(A2)在视网膜缺血再灌注(IR)中起有害作用 损伤，我们开发了一个项目，重点是胞浆的神经血管保护作用 异构型精氨酸酶1(A1)。我们最近发表的论文显示A1的神经保护作用 在髓系细胞中的表达。精氨酸酶与一氧化氮合酶(NOS)的共同之处 底物L-精氨酸。诱导型一氧化氮合酶(INOS)产生的一氧化氮(NO)引起神经血管病变 退化。我们预测，髓系细胞中A1的上调限制了iNOS来源的硝化和 氧化应激，通过其下游代谢物鸟氨酸和 腐胺。腐胺是多胺的前体，它是由鸟氨酸和鸟氨酸形成的 脱羧酶(ODC，多胺生物合成中的限速酶)。这些代谢物 已被证明通过染色质修饰促进修复性髓系细胞。与…一致 这一点，我们的初步数据显示，组蛋白脱乙酰酶(HDAC)3在缺乏 A1在IR损伤的视网膜和刺激的巨噬细胞中均有表达。HDAC3是巨噬细胞所必需的 炎症基因转录，并已被证明抑制A1的表达。在此，我们 提出一种新的A1对HDAC3的抑制作用。我们的中心假说预测髓系细胞 A1通过ODC介导的HDAC3抑制来保护视网膜IR损伤。我们会的 使用具有髓系特异性A1、ODC和HDAC3缺失的小鼠，以及研究 药物，BCT-100(一种聚乙二醇化形式的精氨酸酶1)，以及原代巨噬细胞分离 并使用HDAC3或精氨酸酶下游酶ODC的抑制剂进行治疗。我们的目标是 实现以下目标：第一)确定操纵精氨酸酶途径的效果 视网膜IR损伤中髓系细胞的浸润/活化及BCT的治疗作用 100.第二)描述精氨酸酶途径和HDAC3之间的串扰，并确定 髓系细胞中的A1是否通过抑制HDAC3介导其保护作用。第三) 确定髓系特异性HDAC3缺失在巨噬细胞炎症反应中的作用 以及视网膜神经血管损伤。

Abstract of the parent grant R00EY029373: Retinal ischemia is a major cause of vision loss in common retinal disease conditions including diabetic retinopathy, glaucoma, retinopathy of prematurity, and vein occlusion. This project aims to define the mechanisms of retinal ischemic injury and identify new therapeutic targets. We have previously demonstrated the involvement of the arginase enzyme in retinal neurovascular diseases. Arginase has two isoforms. Building upon the lab's finding that the mitochondrial isoform, arginase 2 (A2), has a deleterious role in retinal ischemia-reperfusion (IR) injury, we developed a project focusing on the neurovascular protective role of the cytosolic isoform arginase 1 (A1). Our recently published papers shows a neuroprotective role of A1 expression in myeloid cells. Arginase competes with nitric oxide synthase (NOS) for their common substrate L-arginine. Nitric oxide (NO) produced by inducible NOS (iNOS) causes neurovascular degeneration. We predict that A1 upregulation in myeloid cells limits iNOS-derived nitrative and oxidative stress and reduces inflammation through its downstream metabolites ornithine and putrescine. Putrescine is the precursor of polyamines and it is formed from ornithine by ornithine decarboxylase (ODC, the rate-limiting enzyme in polyamine biosynthesis). These metabolites have been shown to promote reparative myeloid cells through chromatin modification. In line with this, our preliminary data show that histone deacetylase (HDAC) 3 is increased in the absence of A1 in both IR-injured retinas and stimulated macrophages. HDAC3 is essential for macrophage inflammatory gene transcription and it has been shown to suppress A1 expression. Herein, We propose a novel suppressive effect of A1 on HDAC3. Our central hypothesis predicts that myeloid A1 protects against retinal IR injury through ODC-mediated suppression of HDAC3. We will be using mice with myeloid-specific deletion of A1, ODC and HDAC3, as well as the investigational drug, BCT-100 (a PEGylated form of arginase 1), together with primary macrophages isolation and treatment with inhibitors for HDAC3 or arginase downstream enzyme, ODC. Our goal is to achieve the following objectives: First) Determine the effect of manipulating the arginase pathway on myeloid cells infiltration / activation in retinal IR injury and the therapeutic potential of BCT- 100. Second) Describe the cross talk between the arginase pathway and HDAC3 and determine whether A1 in myeloid cells mediates its protective effect through suppression of HDAC3. Third) Determine the role of myeloid specific deletion of HDAC3 on macrophage inflammatory response and retinal neurovascular injury.