Neuroprotection Mechanism for Photoreceptors

 描述（由申请人提供）：睫状神经营养因子（CNTF）在多种视网膜变性动物模型中作为有效的神经保护剂。近年来，从封装细胞装置分泌的CNTF已在几项临床试验中进行了评估，FDA已授予这种CNTF疗法孤儿药地位，用于治疗视网膜色素变性（RP）和干性年龄相关性黄斑变性（AMD）。然而，尽管CNTF作为不同致盲疾病的广谱治疗剂的潜力，其在视网膜中的作用机制仍然知之甚少。我们以前已经表明，组成性，高水平表达的CNTF防止感光细胞死亡，但改变视网膜基因表达和抑制视觉功能。最近，我们已经探讨了CNTF的作用机制，使用遗传扰动的RP小鼠模型与临床试验中使用的相同的人CNTF治疗。通过进行视网膜细胞类型特异性基因缺失，我们已经表明CNTF的初始靶点是Müller胶质细胞，并且在Müller胶质细胞中没有功能性细胞因子受体，下游信号传导事件和CNTF诱导的感光细胞存活被废除。虽然视杆细胞光感受器不直接响应外源性CNTF，但它们也需要功能性细胞因子受体才能生存。此外，我们提供的证据表明，外源性CNTF刺激和放大Müller胶质细胞和感光细胞之间的信号通路，以促进神经元的活力。然而，尽管在感光细胞形态和活力的显着改善，低水平的外源性CNTF只稳定，但不进一步增强视网膜功能。这项研究将结合联合收割机先进的分子遗传学和系统生物学方法，探讨CNTF诱导视网膜神经保护的机制。我们将通过使用转基因小鼠来确定CNTF在视杆光感受器和Müller胶质细胞中激活的特定信号传导模式的功能。我们将通过比较野生型和突变型视网膜来分析CNTF诱导的视杆细胞表观基因组和转录组水平的变化，以破译影响细胞存活和功能的关键细胞过程。我们还将评估CNTF治疗对病变视网膜细胞代谢的影响，并确定介导该影响的信号效应物。这项研究将促进我们对神经保护机制的理解，深入了解CNTF在人类视网膜中的作用，并促进开发更有效的视网膜变性治疗方法。

 DESCRIPTION (provided by applicant): Ciliary neurotrophic factor (CNTF) acts as a potent neuroprotective agent in a variety of retinal degeneration animal models. In recent years, CNTF secreted from an encapsulated cell device has been evaluated in several clinical trials, and the FDA has granted this CNTF therapy an Orphan Drug Status for the treatment of retinitis pigmentosa (RP) and dry age-related macular degeneration (AMD). Yet despite the potential of CNTF as a broad-spectrum therapeutic agent for different blinding diseases, its mechanisms of action in the retina remain poorly understood. We have shown previously that constitutive, high-level expression of CNTF prevents photoreceptor death but alters retinal gene expression and suppresses visual function. Recently, we have explored the mechanism of CNTF action using genetic perturbations in an RP mouse model treated with the same human CNTF used in clinical trials. By performing retinal cell type specific gene deletions, we have shown that the initial targets of CNTF are Müller glial cells, and without a functional cytokine receptor in Müler glia, downstream signaling events and CNTF-induced photoreceptor survival are abolished. Although the rod photoreceptors do not directly respond to exogenous CNTF, they also require a functional cytokine receptor for survival. Furthermore, we have provided evidence that exogenous CNTF stimulates and amplifies a signaling loop between Müller glia and photoreceptors to promote neuronal viability. However, despite a significant improvement in photoreceptor morphology and viability, low levels of exogenous CNTF only stabilize but do not further enhance retinal function. The proposed research will combine advanced molecular genetics and system biology approaches to investigate the mechanisms underlying CNTF-induced neuroprotection in the retina. We will determine the functions of specific signaling modalities activated by CNTF in rod photoreceptors and Müller glia by using genetically modified mice. We will analyze CNTF-induced changes at the epigenome and transcriptome levels in rod cells by comparing wild type and mutant retinas to decipher critical cellular processes affecting cell survival and function. We will also evaluate the effect of CNTF treatment on cellular metabolism in diseased retinas and define the signaling effector mediating the effect. The proposed research will advance our understanding of neuroprotection mechanisms, provide insight into the effects of CNTF in human retinas, and facilitate the development of more efficacious treatments for retinal degeneration.