The Role of Adenosine in Retinal Ischemia

对缺血耐受引起的内源性神经保护认识上的根本差距 确定视网膜缺血的治疗靶点，这是导致视力丧失的主要原因。牵涉到炎症- 血管紧张素转换酶、神经胶质细胞激活、氧化应激和神经变性与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译机甲- 内源性缺血耐受，作为缺血损伤的创新调节剂。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， 缺血耐受性。中心假说是，它们单独或共同激活，驱动视网膜内分泌- 天生的宽容。这一假设的基础是申请人在大鼠模型中的结果，其中p38被诱发，而 阻断特定Akt亚型，降低缺血耐受性。AKT或p38基因敲除抑制了概念性- LY相关的缺血后条件反射(损伤性缺血后的短暂性缺血)。支持的理由是- POSSAL是，在了解了这些信号机制后，可以精确地调整通路，潜在- LY转化为每年1000万英镑视网膜缺血风险的有效治疗。中心假说 将在三个特定的目标中进行测试：1)识别p38神经保护信号，2)识别Akt神经保护 信号转导，3)确定与p38和Akt相关的延迟缺血后条件反射机制。在目标1中，一个 已建立的RNA干扰方法将研究p38‘S调控和下游机制 缺血耐受性。在目标2中，siRNA将阻断Akt，以及一种新的Akt仿磷病毒载体，其有效性 得到初步数据支持，将过度表达Akt亚型。测量Akt亚型的底物，以及 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 缺血后适应模型、Akt、p38及下游介质的检测将阐明Me- 脑缺血后神经功能恢复的机制。实验结果将在AIMS中进行衡量 1-3通过现代的、经过验证的分子和生理方法，这些方法在申请人的 实验室。通过提供缺血耐受创新地利用内源性神经保护将产生新的靶点 通过启动细胞生存机制来治疗缺血性疾病。这项拟议的研究具有重要意义，因为 预计它将纵向推进和扩大对视网膜内源性细胞机制如何- NERY可用于预防或治疗缺血，同时增加对细胞存活信号的理解 活着。最终，这一知识有可能通过发现新的、 特定的分子干预靶点，将有助于减少日益严重的视力丧失和视力丧失问题- 视网膜缺血性疾病。

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.