Neuroprotection Mechanism for Photoreceptors

项目总结 睫状神经营养因子(CNTF)在多种视网膜变性中起着强有力的神经保护作用 动物模型。近年来，从微囊化细胞装置中分泌的CNTF已经在 几项临床试验，FDA已批准这种CNTF疗法为孤儿药物 视网膜色素变性(RP)和干性老年性黄斑变性(AMD)。然而，尽管存在潜在的 CNTF作为一种治疗不同致盲疾病的广谱药物，其作用机制 人们对视网膜仍然知之甚少。 我们以前已经证明，结构性的、高水平的CNTF表达可以防止光感受器死亡 但会改变视网膜基因的表达，抑制视觉功能。最近，我们探索了 CNTF在RP小鼠模型中利用遗传扰动的作用机制 用于临床试验的人CNTF。通过进行视网膜细胞类型特定基因的删除，我们已经证明 CNTF的最初靶点是Müler神经胶质细胞，在Müler神经胶质细胞中没有功能细胞因子受体， 下游信号事件和CNTF诱导的光感受器存活被取消。虽然这根棍子 光感受器不直接对外源性CNTF产生反应，它们还需要一个功能正常的细胞因子受体 为了生存。此外，我们还提供了外源性CNTF刺激和放大 Müler神经胶质细胞和光感受器之间的信号环促进神经元的存活。然而，尽管 光感受器形态和活性显著改善，仅低水平外源性CNTF 稳定但不会进一步增强视网膜功能。 拟议的研究将结合先进的分子遗传学和系统生物学方法来 探讨CNTF诱导视网膜神经保护的机制。我们将确定 CNTF激活的特定信号通路在视杆细胞光感受器和Müler胶质细胞中的作用 转基因小鼠。我们将分析CNTF引起的表观基因组和转录组的变化 通过比较野生型和突变型视网膜来破译影响视杆细胞的关键细胞过程 细胞的存活和功能。我们还将评估CNTF治疗对小鼠脑内细胞代谢的影响。 病变的视网膜，并定义调节该效应的信号效应因子。拟议的研究将会取得进展 我们对神经保护机制的理解，有助于深入了解CNTF对人类的影响 视网膜，并促进开发更有效的视网膜退化治疗方法。

PROJECT SUMMARY 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 Müller 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 genetic 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.