The Role of Adenosine in Retinal Ischemia

在理解缺血耐受引起的内源性神经保护方面的根本差距阻碍了 确定视网膜缺血的治疗靶点，视网膜缺血是视力丧失的主要原因。炎症的影响- 慢性视网膜缺血性疾病，如糖尿病， 糖尿病视网膜病变，提示神经保护的主要作用。我们的长期目标是破解这个机制- 内源性缺血耐受的机制，作为缺血性损伤的创新调节剂。总体目标是 为了了解两个关键蛋白Akt和p38的激活、控制和下游机制， 缺血耐受核心假设是，它们的激活，单独或一起，驱动视网膜内- 遗传耐受性该假设的基础是申请人在大鼠模型中的结果，其中p38诱发，而 阻断特定Akt亚型，减弱缺血耐受。Akt或p38敲低抑制了概念上的- Ly相关的缺血后调节（损伤性缺血后的短暂缺血）。赞成的理由 在理解了这些信号传导机制之后，这些通路可以被精确地调整，潜在的- 从而转化为对> 1000万/年的视网膜缺血风险的有效治疗。核心假设 将在三个具体目标中进行测试：1）鉴定p38神经保护信号，2）鉴定Akt神经保护信号， 3）确定与p38和Akt相关的延迟缺血后条件反射的机制。在目标1中， 已建立的RNA干扰方法（siRNA）将检查p38的控制和下游机制， 缺血耐受在目标2中，siRNA将阻断Akt，并且一种新的Akt磷酸化模拟病毒载体，其功效 初步数据支持，将过表达Akt亚型。测量Akt亚型的底物，和 通路串扰将阐明神经保护的机制。在目标3中，使用PI的延迟视网膜 缺血后处理模型，Akt，p38和下游介质的检查将阐明该机制。 缺血后神经元功能恢复的机制。实验结果将在Aims中衡量 1-3通过现代的、经验证的分子和生理学方法，这些方法在申请人的 实验室通过提供缺血耐受来创新性地利用内源性神经保护将产生新的靶点 通过激活细胞存活机制来治疗缺血性疾病。这项研究意义重大，因为 它有望垂直推进和扩大对视网膜内源性细胞机制的理解， nery可以用来预防或治疗缺血，同时增加对细胞存活信号的理解， vivo.最终，这些知识有可能通过识别新的， 具体的分子干预目标，这将有助于减少日益严重的问题，视力丧失和disa， 视网膜缺血性疾病的可能性。

The fundamental gap in understanding endogenous neuroprotection evoked by ischemic tolerance impedes identification of therapeutic targets for retinal ischemia, a major cause of visual loss. Involvement of inflamma- tion, glial activation, oxidative stress, and neurodegeneration in chronic retinal ischemic diseases such as di- abetic retinopathy, suggests a primary role for neuroprotection. The long-term goal is to decipher the mechan- isms of endogenous ischemic tolerance, as an innovative modulator of ischemic injury. The overall objective is to understand the activation, control, and downstream mechanisms of two key proteins, Akt and p38, in ischemic tolerance. The central hypothesis is that their activation, individually or together, drives retinal endo- genous tolerance. Underlying the hypothesis is the applicant's results in a rat model wherein p38 evoked, while blocking specific Akt subtypes, attenuated ischemic tolerance. Akt or p38 knockdown inhibited the conceptual- ly-related post-ischemic conditioning (transient ischemia after the damaging ischemia). Rationale for the pro- posal is that, after understanding these signaling mechanisms, the pathways can be precisely tuned, potential- ly translating into effective treatment for the > 10 million/year at risk for retinal ischemia. The central hypothesis will be tested in three specific aims: 1) Identify p38 neuroprotective signaling, 2) Identify Akt neuroprotective signaling, 3) Determine mechanisms of delayed post-ischemic conditioning related to p38 and Akt. In Aim 1, an established RNA interference approach (siRNA) will examine p38's control and downstream mechanisms in ischemic tolerance. In Aim 2, siRNA will block Akt, and a novel Akt phosphomimetic viral vector whose efficacy is supported by preliminary data, will overexpress Akt subtypes. Measuring substrates of Akt subtypes, and pathway cross-talk will illuminate the mechanisms of neuroprotection. In Aim 3, using the PI's delayed retinal ischemic post-conditioning model, examination of Akt, p38, and downstream mediators will elucidate the me- chanisms of restoration of post-ischemic neuronal function. Experimental outcomes will be measured in Aims 1-3 by modern, validated molecular and physiological approaches that are well established in the applicant's lab. Innovatively exploiting endogenous neuroprotection by providing ischemic tolerance will yield novel targets to treat ischemic disease by engaging cell survival mechanisms. The proposed research is significant because it is expected to vertically advance and expand understanding of how the retina's endogenous cellular machi- nery can be harnessed to prevent or treat ischemia, while increasing understanding of cell survival signaling in vivo. Ultimately, this knowledge has potential to transform treatment of retinal ischemia by identifying novel, specific molecular interventional targets that will help to decrease the growing problem of visual loss and disa- bility from ischemic disease in the retina.