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NADPH oxidase, mitochondrial dysfunction and diabetic retinopathy

NADPH 氧化酶、线粒体功能障碍和糖尿病视网膜病变

基本信息

批准号：
10357931
负责人：
RENU A. KOWLURU
金额：
$ 37.35万
依托单位：
WAYNE STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-04-01 至 2024-02-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10357931
关键词：
Address Anabolism Animal Model Apoptosis Apoptotic Binding Biological Blindness Blood capillaries Cells Ceramides Complex Complications of Diabetes Mellitus Cytosine DNA DNA Methylation DNA Modification Methylases DNA Modification Process DNA Sequence Data Development Diabetes Mellitus Diabetic Retinopathy Disease Dyslipidemias Electron Transport Endothelial Cells Enzymes Epigenetic Process Exposure to Funding G-Protein Signaling Pathway GTP Binding GTPase-Activating Proteins Gene Expression Genes Genetic Transcription Goals Guanine Guanine Nucleotide Dissociation Inhibitors Guanine Nucleotide Exchange Factors Holoenzymes Human Hydroxyl Radical Hydroxylation Hyperglycemia Hyperlipidemia Laboratories Lipids Mediating Membrane Messenger RNA Methodology Methylation Mitochondria Modification Molecular Monomeric GTP-Binding Proteins NADPH Oxidase NF-kappa B Non-Insulin-Dependent Diabetes Mellitus Pathogenesis Patients Pattern Pharmacology Post-Translational Protein Processing Prediabetes syndrome Process Production Protein Isoprenylation Publishing Reactive Oxygen Species Regulation Reporting Research Retina Retinal Diseases Rodent Rodent Model Role Signal Transduction Structure Testing Tetanus Helper Peptide Therapeutic Transcript Transcriptional Activation Transcriptional Regulation Translating Type 2 diabetic Vision Work base diabetic gene induction gene repression in vitro Model in vivo inhibitor innovation member methyl group mitochondrial dysfunction multidisciplinary new therapeutic target novel predictive modeling prenylation prevent promoter rac1 GTP-Binding Protein small molecule inhibitor thermozymocidin translational impact translational potential translocase young adult

项目摘要

Diabetic retinopathy remains a major cause of blindness, and despite cutting edge research in the field, the molecular mechanism of its pathogenesis remains unclear. Our recent research has shown that during early stages of this progressing disease, activation of cytosolic NADPH oxidase 2 (Nox2) generates reactive oxygen species (ROS), and sustained increase in cytosolic ROS damages mitochondrial structure and its DNA, dysregulating the electron transport chain and initiating a vicious cycle of ROS. Furthermore, we have shown that dyslipidemia accelerates Nox2-mediated mitochondrial damage and the development of diabetic retinopathy in a type 2 diabetic animal model. An integral part of the cytosolic core of Nox2 holoenzyme is the small G-protein, Rac1, and diabetes increases Rac1 activity and gene transcripts in retinal microvasculature. Rac1 functional activation is mediated by its binding with the guanine exchange factors (GEFs) and guanine nucleotide dissociation inhibitors (GDIs). Many epigenetic modifications are also favored by diabetic milieu, and these covalent modifications regulate gene expression without altering the DNA sequence. Thus, the central hypothesis of the current application is that covalent modifications of Rac1 modulate its functional and transcriptional activation, and activated Rac1, via Nox2-mediated ROS production, damages the mitochondria, resulting in accelerated apoptosis and the development of diabetic retinopathy. Aim 1 will investigate the molecular mechanism(s) by which hyperglycemia promotes activation of Rac1. Our model predicts that defective prenylation of Rac1 results in its sustained activation and mislocalization, and dynamic DNA methylation- hydroxymethylation of Rac1 promoter facilitates its transcriptional activation. Aim 2 will delineate the mechanism(s) by which gluco/lipotoxicity accelerates the development of diabetic retinopathy, and will investigate the effect of dyslipidemia on functional and transcriptional activation of Rac1. Questions asked under Aim 3 will address the therapeutic potential of regulation of Rac1 activation on inhibition of diabetic retinopathy, and will test novel small molecule inhibitors of GEF and of ceramide biosynthesis. The plan will employ fully optimized molecular biological and pharmacological approaches to assess the effect of diabetes on functional and transcriptional regulation of Rac1 activation in isolated retinal endothelial cells in culture, and in retinal microvessels from (pre-, type 1 and type 2) diabetic rodent models and from human donors with established diabetic retinopathy. Our overall goal is to identify novel regulatory mechanisms involved in the pathogenesis of diabetic retinopathy, specifically at the level of functional and transcriptional regulation of Rac1. The proposal is based on a testable central hypothesis, and these innovative studies carry a significant translational impact as they are expected to identify novel therapeutic targets to inhibit the development and progression of diabetic retinopathy.

糖尿病视网膜病变仍然是导致失明的主要原因，尽管在该领域进行了尖端研究，但其发病的分子机制尚不清楚。我们最近的研究表明，在早期在疾病进展的各个阶段，胞浆NADPH氧化酶2(NOX2)的激活会产生活性氧物种(ROS)，胞质ROS的持续增加破坏线粒体结构及其DNA，电子传递链失调，启动ROS的恶性循环。此外，我们已经展示了血脂异常加速NOX2介导的线粒体损伤和糖尿病的发生发展 2型糖尿病动物模型中的视网膜病变。NOX2全酶的胞浆核心的一个组成部分是小G蛋白、rac1和糖尿病可增加视网膜微血管中rac1的活性和基因转录。 Rac1的功能激活是由其与鸟嘌呤交换因子(GEF)和鸟嘌呤结合介导的核苷酸解离抑制剂(GDIs)。许多表观遗传修饰也受到糖尿病环境的青睐，这些共价修饰在不改变DNA序列的情况下调节基因的表达。因此，目前应用的中心假设是，rac1的共价修饰调节其功能和转录激活，并通过NOX2介导的ROS产生激活的rac1，损伤线粒体，从而加速细胞凋亡，发展为糖尿病视网膜病变。目的1研究高血糖促进RAC1活化的分子机制(S)。我们的模型预测，rac1的缺陷预烯基化导致其持续激活和错误定位，并且 Rac1启动子的动态DNA甲基化-羟甲基化促进其转录激活。目标2 将描述糖脂毒性加速糖尿病视网膜病变发展的机制(S)，并将研究血脂异常对rac1功能和转录激活的影响。问题根据目标3的要求，将解决调节rac1激活对抑制糖尿病视网膜病变，并将测试新的小分子抑制剂的环境基金和神经酰胺的生物合成。这个该计划将采用完全优化的分子生物学和药理学方法来评估糖尿病对视网膜内皮细胞rac1激活的功能和转录调节作用培养，以及(前期、1型和2型)糖尿病啮齿动物模型和人类的视网膜微血管患有糖尿病视网膜病变的捐献者。我们的总体目标是确定新的监管机制参与糖尿病视网膜病变的发病机制，特别是在功能和转录水平对rac1的调控。该提案基于一个可验证的中心假设，这些创新研究进行了显著的翻译影响，因为他们有望找到新的治疗靶点来抑制糖尿病视网膜病变的发生发展。

项目成果

期刊论文数量（5）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

P-Rex1 Mediates Glucose-Stimulated Rac1 Activation and Insulin Secretion in Pancreatic β-Cells.

DOI：
10.33594/000000310
发表时间：
2020-12-12
期刊：
CELLULAR PHYSIOLOGY AND BIOCHEMISTRY
影响因子：
0
作者：
Thamilselvan, Vijayalakshmi;Gamage, Suhadinie;Harajli, Ali;Chundru, Sri Aneesha;Kowluru, Anjaneyulu
通讯作者：
Kowluru, Anjaneyulu

Potential roles of PP2A-Rac1 signaling axis in pancreatic β-cell dysfunction under metabolic stress: Progress and promise.