CaMKII as a regulator of diabetic retinopathy

描述(由申请人提供)： 目前通过退伍军人系统接受医疗保健的退伍军人中，近25%的人被诊断为糖尿病。几乎所有患有1型糖尿病的退伍军人和60%患有2型糖尿病的退伍军人在疾病的头20年里都会患上视网膜病变，1%的人会经历严重的视力丧失或失明。目前的治疗方法只在50%的退伍军人中提供了临床上有意义的改善。因此，迫切需要确定DR的调节者，这可以作为治疗的靶向，并将直接使一大批退伍军人受益。我们推测，高血糖条件下的多功能钙/钙调蛋白依赖的激酶II(CaMKII)促进了糖尿病视网膜病变(DR)的内皮病理特征，特别是内皮细胞的凋亡和屏障功能障碍。因此，抑制CaMKII可能是预防或治疗DR的一种有效的新方法。Grumach实验室的长期目标是研究CaMKII在血管系统中的功能，特别是CaMKII的调节，作为治疗血管疾病的新方法。本项目的目的是确定内皮细胞中特异的CaMKII抑制物是否可以防止非增殖性DR。中心假说是，CaMKII抑制物通过阻止内皮细胞凋亡和屏障功能障碍(非增殖性DR的两种关键表型)来减少非增殖性DR。我们将在一种新型的体内小鼠模型中验证这一假说，在该模型中，强大而特异的内源性CaMKII抑制剂CaMKIIN选择性地在内皮细胞中过表达，并在体外剖析分子机制。提出这项研究的基本原理是，了解CaMKII是否在体内调节非增殖性DR的表型变化并驱动内皮细胞ROS的产生、凋亡和屏障功能可能是设计特定的CaMKII抑制剂以预防和缓解DR的关键第一步。我们将在两个特定目标上验证我们的中心假设：1)确定体内CaMKII对非增殖性DR的作用；2)体外：鉴定CaMKII是否在体外高糖条件下控制内皮功能障碍。在第一个目标中，我们将使用新的体内模型来测试抑制CaMKII是否能够保护非增殖性DR的视网膜微血管结构和功能。在Aim 2中，我们将确定在高血糖下CaMKII被激活并在体外调节屏障功能、细胞凋亡和ROS产生的机制。这种方法是创新的，因为它使用了新的活体模型和成像技术以及特定的工具来剖析CaMKII信号。这项拟议的研究具有重要意义，因为它有望通过将CaMKII定义为控制DR内皮细胞表型的新分子靶点来推动该领域的发展。最终，这种知识可能允许开发新的DR治疗策略，使我们的退伍军人受益。

DESCRIPTION (provided by applicant): Almost 25% of the veterans that are currently receiving healthcare through the VA system carry the diagnosis of diabetes. Nearly all veterans with type 1 diabetes and >60% of veterans with type 2 develop retinopathy during the first two decades of disease, 1% will experience severe visual loss or blindness. Current therapies provide clinically meaningful improvement in only 50% of veterans. Thus, there is a critical need to identify regulators of DR, which can be targeted therapeutically and will directly benefit a large group of veterans. We hypothesize that the multifunctional Ca2+/calmodulin-dependent kinase II (CaMKII) under hyperglycemic conditions promotes the endothelial pathology characteristic for diabetic retinopathy (DR), in particular endothelial apoptosis and barrier dysfunction. Thus, CaMKII inhibition may be a potent novel approach to prevent or treat DR. The long-term goal of the Grumbach lab is to study the function of CaMKII in the vasculature, specifically CaMKII modulation as a new approach to treat vascular disease. The objective of this project is to determine whether specific CaMKII inhibition in endothelium prevents non-proliferative DR. The central hypothesis is that CaMKII inhibition decreases non-proliferative DR by preventing endothelial apoptosis and barrier dysfunction, two key phenotypes of non-proliferative DR. We will test the hypothesis in a novel in vivo mouse model in which the potent and specific endogenous CaMKII inhibitor CaMKIIN is selectively overexpressed in endothelium and dissect molecular mechanisms in vitro. The rationale for the proposed studies is that, understanding whether CaMKII regulates the phenotypic changes of non- proliferative DR in vivo and drives endothelial cells ROS-production, apoptosis and barrier function may be a critical first step towards designing a specific CaMKII inhibitor to prevent and alleviate DR. We will test our central hypothesis in two specific aims: 1) Determine the role of endothelial CaMKII on non-proliferative DR in vivo, 2): Characterize whether CaMKII controls endothelial dysfunction under high glucose conditions in vitro. In the first aim, the novel in vivo model will be used to test whether CaMKII inhibition wil preserve retinal microvascular structure and function in non-proliferative DR. Under aim 2, we will define the mechanisms through which CaMKII is activated under hyperglycemia and regulates barrier function, apoptosis and ROS production in vitro. The approach is innovative because of its use of novel in vivo models and imaging techniques and specific tools to dissect CaMKII signaling. The proposed research is significant because it is expected to advance the field by defining CaMKII as a novel molecular target that controls endothelial phenotypes in DR. Ultimately, such knowledge may allow for the development of new therapeutic strategies in DR that will benefits our veterans.