Role of calcium channels in the development of diabetic retinopathy

钙通道在糖尿病视网膜病变发展中的作用

基本信息

批准号：
8635018
负责人：
BRUCE A. BERKOWITZ
金额：
$ 19万
依托单位：
WAYNE STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-02-01 至 2016-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8635018
关键词：
Aging Appearance Area Biochemistry Blindness Blood Vessels Calcium Calcium Channel Calcium Channel Blockers Clinical Complications of Diabetes Mellitus Decision Making Development Diabetes Mellitus Diabetic Retinopathy Etiology Free Radicals Functional disorder Future Genetic Goals Histopathology Imaging Techniques Knockout Mice L-Type Calcium Channels Lead Lesion Link Magnetic Resonance Imaging Manganese Measurement Mediating Methodology Mission Mitochondria Modeling Molecular Target Morbidity - disease rate Mus Neurons Oxidants Oxidative Stress Pathogenesis Patients Phenotype Photoreceptors Prevention Public Health Reactive Oxygen Species Research Resolution Retina Retinal Retinal Diseases Role Signal Transduction Structure of retinal pigment epithelium Testing Therapeutic Thinking Trypsin Western Blotting Work analytical tool base biophysical properties brain tissue cell type diabetic diabetic patient effective therapy experience extracellular free radical oxygen improved in vivo in vivo imaging innovation novel preclinical study prevent public health relevance research study

项目摘要

DESCRIPTION (provided by applicant): There remains an urgent need to prevent vision loss from diabetic retinopathy (DR), a common and significant problem in patients with diabetes. Preclinical studies have highlighted retinal oxidative stress in the pathogenesis of DR. We reason that identifying the retinal mechanisms mediating pathogenic oxidative stress in diabetes will be important in the development of new and effective treatments. In neurons, oxidative stress and L-type calcium channels (LTCCs) activity are closely linked: increased LTCC activity elevates intracellular calcium content which must then be removed against a steep inter/extracellular calcium concentration gradient via ATP-dependent mechanisms which generate oxygen free radicals. We have discovered that diabetes profoundly changes the overall activity of photoreceptor LTCCs. Remarkably, a non-anti-oxidant and photoreceptor-specific treatment that corrected the abnormal outer retinal LTCC phenotype in vivo concurrently eliminated diabetic retinal oxidative stress. These experiments, using a validated and analytical tool (MEMRI), provide the first evidence for an unexpected and potentially very important discovery linking abnormal photoreceptor LTCCs and oxidative stress in diabetes. In the retina there are 3 major LTCC subtypes (Cav): Cav1.2 (located in inner retina), Cav1.3 (in inner retina, photoreceptor, and retinal pigment epithelium layers), and Cav1.4 (only in photoreceptors. How diabetes alters photoreceptor subtype channels are not yet known. We hypothesized that diabetes induces reproducible abnormalities in photoreceptor Cav1.3 and 1.4 expression and activity, and these changes actively contribute to oxidative stress and diabetic retinopathy. To begin to evaluate our new working hypothesis, we propose the following specific aim, which will take full advantage of our expertise in blending high resolution and analytical in vivo imaging of photoreceptor pathophysiology (manganese-enhanced MRI) with biochemistry (reactive oxygen species, western blot analysis (channel expression)) and histopathology (trypsin digest) in models of DR. SA 1: Test that diabetic alterations in photoreceptor Cav1.3, and 1.4 LTCC activity are required for oxidative stress and DR. The proposed experiments will open up a new line of scientific inquiry that is expected to improve our understanding about the origins of oxidative stress in DR. Because Cav1.3 and 1.4 subtypes are relatively insensitive to commonly used calcium channel blockers, our specific genetic and pharmacological approaches in concert with a novel imaging technique make these studies highly significant. These experiments will be crucial in the identification of new molecular targets for prevention and treatment of DR. The proposed research is highly innovative because it investigates a previously unsuspected but key role of photoreceptor LTCC subtype abnormalities in diabetes-induced oxidative stress, and will thus establish a firm scientific basis for changing current thinking regarding the origins of, and therapeutic options for, pathogenic oxidative stress in DR.

描述（由申请人提供）：仍然迫切需要预防糖尿病视网膜病变（DR）引起的视力丧失，糖尿病视网膜病变是糖尿病患者的一个常见且重要的问题。临床前研究强调了视网膜氧化应激在 DR 发病机制中的作用。我们认为，确定介导糖尿病致病性氧化应激的视网膜机制对于开发新的有效治疗方法非常重要。在神经元中，氧化应激和 L 型钙通道 (LTCC) 活性密切相关：LTCC 活性增加会提高细胞内钙含量，然后必须通过 ATP 依赖性机制产生氧自由基，以对抗陡峭的细胞内/外钙浓度梯度将其去除。我们发现糖尿病深刻改变了光感受器 LTCC 的整体活性。值得注意的是，非抗氧化剂和光感受器特异性治疗在体内纠正了异常的外视网膜 LTCC 表型，同时消除了糖尿病视网膜氧化应激。这些实验使用经过验证的分析工具 (MEMRI)，为意外且可能非常重要的发现提供了第一个证据，该发现将异常光感受器 LTCC 与糖尿病中的氧化应激联系起来。视网膜中有 3 种主要的 LTCC 亚型 (Cav)：Cav1.2（位于视网膜内层）、Cav1.3（位于视网膜内层、感光细胞和视网膜色素上皮层）和 Cav1.4（仅存在于感光细胞中）。糖尿病会改变光感受器亚型通道尚不清楚，我们假设糖尿病会导致光感受器 Cav1.3 和 1.4 表达出现可重复的异常。为了开始评估我们的新工作假设，我们提出以下具体目标，该目标将充分利用我们在光感受器病理生理学的高分辨率和分析体内成像方面的专业知识。（锰增强 MRI）与 DR 模型中的生物化学（活性氧、蛋白质印迹分析（通道表达））和组织病理学（胰蛋白酶消化）SA 1：测试光感受器的糖尿病改变。 Cav1.3 和 1.4 LTCC 活性是氧化应激和 DR 所必需的。拟议的实验将开辟一条新的科学探究路线，有望提高我们对 DR 氧化应激起源的理解。由于 Cav1.3 和 1.4 亚型对常用的钙通道阻滞剂相对不敏感，因此我们特定的遗传和药理学方法与新颖的成像技术相结合，使这些研究非常重要。这些实验对于确定预防和治疗 DR 的新分子靶点至关重要。拟议的研究具有高度创新性，因为它调查了光感受器 LTCC 亚型异常在糖尿病引起的氧化应激中先前未被怀疑但关键的作用，因此将为改变当前关于致病性起源和治疗选择的想法奠定坚实的科学基础。 DR 中的氧化应激。