CaMKII as a regulator of diabetic retinopathy

描述（由申请人提供）： 目前通过VA系统接受医疗保健的退伍军人中，近25%患有糖尿病。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前二十年内发展视网膜病变，1%将经历严重的视力丧失或失明。目前的治疗方法只对50%的退伍军人提供了有临床意义的改善。因此，迫切需要确定DR的调节因子，这些调节因子可以在治疗上靶向，并将直接使一大群退伍军人受益。我们推测，多功能钙/钙调蛋白依赖性激酶II（CaMKII）在高血糖条件下促进糖尿病视网膜病变（DR）的内皮病理特征，特别是内皮细胞凋亡和屏障功能障碍。因此，CaMKII抑制可能是预防或治疗DR的有效新方法。Grumbach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调节作为治疗血管疾病的新方法。该项目的目的是确定内皮中的特异性CaMKII抑制是否防止非增殖性DR。中心假设是CaMKII抑制通过防止内皮细胞凋亡和屏障功能障碍来减少非增殖性DR，两种关键的非我们将在一种新的体内小鼠模型中检验这一假设，在该模型中，有效的和特异性的内源性CaMKII抑制剂CaMKIIN选择性地过表达并在体外研究其分子机制。所提出的研究的基本原理是，理解CaMKII是否调节体内非增殖性DR的表型变化并驱动内皮细胞ROS产生、凋亡和屏障功能可能是设计特异性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中测试我们的中心假设：1）确定内皮CaMK II在体内对非增殖性DR的作用，2）：表征CaMK II是否在体外高葡萄糖条件下控制内皮功能障碍。在第一个目标中，新的体内模型将用于测试CaMKII抑制是否会在非增殖性DR中保留视网膜微血管结构和功能。在目标2中，我们将定义CaMKII在高血糖下激活并调节屏障功能、细胞凋亡和体外ROS产生的机制。该方法是创新的，因为它使用了新的体内模型和成像技术和特定的工具来剖析CaMKII信号。拟议的研究是重要的，因为它预计将通过定义CaMKII作为一种新的分子靶点，控制DR中的内皮表型，从而推进该领域。最终，这些知识可能会允许在DR中开发新的治疗策略，这将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.