Insulin-therapy resistant epigenetic modifications in diabetic retinopathy

摘要 糖尿病视网膜病变仍然是工作年龄成年人失明的主要原因。目前没有 除了胰岛素替代疗法外，已批准并证明的糖尿病视网膜病变治疗方法， 血压控制。最近的纵向研究报告表明，尽管实现了稳定的 血糖水平和HbA 1c控制，以前接受非强化胰岛素治疗的患者继续有 糖尿病视网膜病变和其他并发症的发病率更高。这是第一次大规模的 代谢记忆假说的临床证据，其中一段时间的糖尿病管理不善 在得到良好控制后， 办妥了一批了解代谢记忆在并发症发展中的作用是非常必要的， 记忆现象显然不能通过目前的治疗方案克服。这种临床现象也 导致了这样的问题，即在控制不良期间发生了哪些分子事件，以及这些事件如何持续存在， 在血糖控制良好的情况下，这项建议旨在通过一项 研究假设控制不良导致表观基因组变化，这些变化不能完全逆转， 改善糖尿病管理。在本研究中，我们将定义视网膜基因启动子DNA 在血糖控制可变的糖尿病背景下，甲基化和相关的染色质修饰。 然后，我们将使用生物信息学工具来比较表观遗传状态与视网膜基因/蛋白质表达。 表观遗传变化将通过正交方法和所得的转录本和蛋白质 表达变化将局限于特定的视网膜层和细胞类型。最后，调节的过程 将检查DNA甲基化和组蛋白修饰。这些研究将作为未来的基础。 寻求维持或恢复正常视网膜表观遗传状态以及 机制研究，调查特定基因如何被靶向进行表观遗传修饰， 高血糖症

Abstract Diabetic retinopathy remains the leading cause of blindness in working age adults. Currently, there are no approved and demonstrated treatments for diabetic retinopathy aside from insulin replacement therapy and blood pressure control. Recent longitudinal study reports have demonstrated that despite achieving stable blood glucose levels and HbA1c control, patients formerly under non-intensive insulin therapy continue to have a higher rate of developing diabetic retinopathy, and other complications. This provides the first large-scale clinical evidence for the hypothesis of metabolic memory, in which a period of poor diabetes management continues to impact development of retinopathy and other complications for years after good control has been achieved. Understanding the role of metabolic memory in complication development is vitally needed as the memory phenomenon is obviously not overcome by current treatment regimens. This clinical phenomenon also leads to the questions of what molecular events occur during poor control and how do these events persist for years after good glycemic control is established. This proposal seeks to address this issue through an investigation of the hypothesis that poor control causes epigenomic changes that are not fully reversed with improved diabetes management. In the proposed studies we will define retinal gene promoter DNA methylation and associated chromatin modifications in the context of diabetes with variable glycemic control. We will then use bioinformatic tools to compare the epigenetic state to retinal gene/protein expression. Epigenetic changes will be confirmed by orthogonal methods and the resulting transcript and protein expression changes will be localized to specific retinal layers and cell types. Lastly the processes that regulate DNA methylation and histone modification will be examined. These studies will serve as the basis for future interventional studies which seek to maintain or return the normal retina epigenetic state as well as mechanistic studies investigating how specific genes are targeted for epigenetic modifications during hyperglycemia.