Uncoupling caspase 8-mediated-apotosis from caspase 8-mediated-inflammation in glaucoma.

将青光眼中 caspase 8 介导的细胞凋亡与 caspase 8 介导的炎症解偶联。

基本信息

批准号：
9919567
负责人：
MEREDITH GREGORY-KSANDER
金额：
$ 24.63万
依托单位：
SCHEPENS EYE RESEARCH INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-05-01 至 2022-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9919567
关键词：
Anti-Inflammatory Agents Apoptosis Apoptotic Axon BAX gene Blindness CASP3 gene CASP8 gene CCL2 gene CD95 Antigens CRISPR/Cas technology Cell Death Cells Cessation of life Chronic Chronic Disease Cleaved cell Complex Data Development Etanercept Event Experimental Models Glaucoma Goals Grant Induction of Apoptosis Inflammation Inflammation Mediators Inflammatory Interleukin-1 beta Interleukin-6 Laboratories Ligand Binding Link Literature Mediating Microglia Microspheres Minocycline Modeling Molecular Mus Mutant Strains Mice Optic Disk Optic Nerve Pathway interactions Pharmaceutical Preparations Play Point Mutation Publishing Research Retina Retinal Ganglion Cells Role Signal Pathway Signal Transduction Site Testing Tumor Necrosis Factor Ligand Superfamily Member 6 Work axon injury axonal degeneration chemokine cytokine human model mouse model neuronal cell body neuroprotection neurotoxic novel strategies prevent retinal apoptosis

项目摘要

One important unanswered question in glaucoma is whether apoptosis of retinal ganglion cells (RGCs) and axon degeneration are two separate events mediated by molecularly distinct pathways, or whether they are linked and triggered through a common pathway. Answering this question is critical to developing effective neuroprotective therapies that protect both axons and RGC somas. In support of the idea there are two distinct pathways that mediate axon degeneration and RGC apoptosis, it was demonstrated that deletion of the pro- apoptotic BAX gene blocked apoptosis of RGCs in a mouse model of glaucoma, but did not prevent axon degeneration. There is accumulating evidence that axon degeneration is triggered by axon damage in the optic nerve head, which precedes RGC apoptosis and is linked to microglial activation and neurotoxic inflammation. Therefore, it is possible that blocking inflammation could prevent axon degeneration and subsequent death of RGCs, leaving open the possibility that there is a shared pathway linking axon degeneration and RGC apoptosis. In support of the idea that inflammation may be the shared pathway that links axon degeneration and RGC apoptosis, our laboratory demonstrated previously that blocking the Fas/Fas ligand (FasL) signaling pathway prevents axon degeneration and RGC apoptosis in both inducible and chronic mouse models of glaucoma and this protection coincided with an inhibition of microglia activation and induction of inflammatory mediators. However, since Fas triggers apoptotic and inflammatory pathways, the question remains as to whether blocking inflammation alone would prevent axon degeneration and subsequent RGC apoptosis. The challenge to resolving this issue is the inability to uncouple Fas-mediated inflammation from Fas-mediated apoptosis. However, Fas signaling requires activation of caspase-8 for both apoptosis and inflammation and recent studies examining the molecular mechanism of caspase-8 activation discovered an additional auto- cleavage step that is required for the induction of caspase-8-mediated apoptosis but not required for induction of caspase-8 mediated inflammation. Using this information, a mutant mouse was created (Casp8DA/DA) in which a point mutation in the auto-cleavage site blocked caspase-8-mediated apoptosis, but did not block caspase-8-mediated inflammation. We will use these mice to definitively determine how caspase-8-mediated inflammation and/or apoptosis triggers axon degeneration and RGC apoptosis in glaucoma. We hypothesize that elevated IOP triggers caspase-8-mediated inflammation that acts as a common pathway triggering axon degeneration and RGC apoptosis. This hypothesis will be tested in two aims: (1) Determine whether caspase- 8-mediated apoptosis contributes to axon degeneration and death of RGCs in a microbead-induced mouse model of glaucoma and (2) Demonstrate that Fas-mediated activation of microglia mediates neurotoxic inflammation, axon degeneration, and death of RGCs in the microbead-induced mouse model of glaucoma.

青光眼中一个尚未解答的重要问题是视网膜神经节细胞 (RGC) 的凋亡是否与视网膜神经节细胞 (RGC) 的凋亡有关？轴突变性是由分子上不同的途径介导的两个独立的事件，或者它们是否是通过共同的途径联系和触发。回答这个问题对于开发有效的保护轴突和 RGC 体细胞的神经保护疗法。为了支持这个想法，有两个不同的介导轴突变性和 RGC 凋亡的途径，结果表明，pro-的缺失凋亡的 BAX 基因可阻断青光眼小鼠模型中 RGC 的凋亡，但不会阻止轴突退化。越来越多的证据表明轴突变性是由视神经轴突损伤引发的神经头，先于 RGC 凋亡，与小胶质细胞激活和神经毒性炎症有关。因此，阻断炎症可能可以防止轴突变性和随后的死亡 RGC，保留了连接轴突变性和 RGC 之间存在共享途径的可能性细胞凋亡。支持炎症可能是连接轴突变性的共同途径的观点和 RGC 细胞凋亡，我们的实验室之前证明，阻断 Fas/Fas 配体 (FasL) 信号传导途径可防止诱导型和慢性小鼠模型中的轴突变性和 RGC 凋亡青光眼和这种保护作用与抑制小胶质细胞激活和诱导炎症同时发生调解员。然而，由于 Fas 触发细胞凋亡和炎症途径，因此问题仍然存在：单独阻断炎症是否可以防止轴突变性和随后的 RGC 凋亡。这解决这个问题的挑战是无法将 Fas 介导的炎症与 Fas 介导的炎症分开细胞凋亡。然而，Fas 信号传导需要激活 caspase-8 来促进细胞凋亡和炎症，最近研究 caspase-8 激活的分子机制发现了一个额外的自动诱导 caspase-8 介导的细胞凋亡所需的裂解步骤，但诱导过程不需要 caspase-8 介导的炎症。利用这些信息，我们创建了突变小鼠 (Casp8DA/DA) 自动切割位点的点突变阻断了 caspase-8 介导的细胞凋亡，但没有阻断 caspase-8 介导的炎症。我们将使用这些小鼠来明确确定 caspase-8 介导的炎症和/或细胞凋亡引发青光眼中的轴突变性和 RGC 细胞凋亡。我们假设升高的 IOP 会触发 caspase-8 介导的炎症，该炎症是触发轴突的常见途径变性和 RGC 凋亡。该假设将在两个目标上进行检验：（1）确定 caspase- 8 介导的细胞凋亡导致微珠诱导的小鼠 RGC 轴突变性和死亡青光眼模型和 (2) 证明 Fas 介导的小胶质细胞激活介导神经毒性微珠诱导的小鼠青光眼模型中的炎症、轴突变性和 RGC 死亡。