Necroptosis and Neuroprotection in AMD

描述(申请人提供)：神经细胞死亡发生在许多视网膜退行性变中，包括AMD。尽管湿性AMD有部分治疗方法，但尚无有效治疗干性AMD的方法，干性AMD的特征是视网膜色素上皮细胞和感光细胞的进行性丧失。因此，迫切需要有效的神经保护，但不幸的是，目前还没有有效的治疗方法。尽管细胞凋亡已被证明是细胞死亡的一种主要形式，但仅基于抑制这一重要方式的干预未能达到预期的目标。我们最近证明，在视网膜脱离的视网膜变性模型中，除了caspase依赖的细胞凋亡外，RIP激酶介导的坏死(也称为坏死性下垂)也参与了光感受器的死亡，有效的神经保护需要联合治疗。我们建议研究RIP激酶途径与caspase的结合是否可以成为其他视网膜变性动物模型(如AMD)的新治疗靶点。Yang et al(NEJM 2008)发现TLR3基因多态性与AMD相关，PolyI：C(dsRNA的类似物)介导的TLR3在动物体内的激活会导致萎缩性AMD样改变。此外，来自美国和其他实验室的几项研究表明，骨髓来源的巨噬细胞/小胶质细胞在动物模型中对视网膜退化有显著贡献。我们已经看到，RIP3-/-基因缺失可以减少炎症的渗透，但如果从所有细胞或免疫细胞中删除RIP3/-是否足以起到神经保护作用，这一问题仍未得到回答。我们建议通过评估RIPK和Caspase抑制(单独和联合使用)在AMD Poly I：C模型中的神经保护作用，将我们关于细胞死亡途径冗余的发现从视网膜脱离模型扩展到AMD动物模型。除了进一步研究神经保护机制外，我们还将通过在WT和RIP3-/-小鼠之间进行骨髓移植(BMT)来研究免疫系统在RIP3-/-视网膜毒性模型中的神经保护机制中的作用。

DESCRIPTION (provided by applicant): Neural cell death occurs in many retinal degenerations including AMD. Although partial therapies exist for the "wet" form of AMD there is no effective therapy for the "dry" form, which is characterized by progressive loss of retinal pigment epithelial cells and photoreceptors. Thus, effective neuroprotection is urgently needed but unfortunately there are no effective treatments currently available. Although apoptosis has been shown to be a major form of cell death, interventions based solely on inhibition of this important modality have failed to achieve the desired goal. We recently demonstrated that RIP kinase-mediated necrosis (also known as necroptosis) in addition to caspase-dependent apoptosis is involved in photoreceptor death in a retinal detachment model of retinal degeneration and that effective neuroprotection necessitates combination therapy. We propose to study whether the RIP kinase pathway in combination with caspases can be a novel therapeutic target in other animal models of retinal degeneration such as AMD. Yang et al (NEJM 2008) identified TLR3 polymorphism to be associated with AMD and that PolyI:C (analog of dsRNA) mediated activation of TLR 3 in animals leads to atrophic AMD like changes. Additionally, several studies from us and other laboratories have shown that bone-marrow (BM) derived macrophages/microglia significantly contribute to retinal degeneration in animal models. We have seen that RIP3-/- genetic deletion decreases inflammatory infiltrate but it remains unanswered if RIP3-/- deletion from all cells or from immune cells can suffice for neuroprotection. We propose to expand our findings on the redundancy of cell death pathways from the retinal detachment model to animal models of AMD by evaluating the neuroprotective effects of RIPK and Caspase Inhibition (alone and in combination) in the Poly I:C model of AMD. In addition to further examine the mechanism of neuroprotection we will study the role of immune system in the mechanism of RIP3-/- neuroprotection in the poly I:C model of retinal toxicity by performing Bone Marrow Transplant (BMT) between WT and RIP3-/- mice.