Neurotoxicity of Reactive Astrocyte-secreted Lipids in Neurodegenerative Disease

项目总结 青光眼是一种以视网膜神经节细胞神经元死亡为特征的神经退行性疾病。 视网膜中的视网膜节细胞(RGCs)，通常是由于眼压持续升高所致。这种细胞死亡导致了 视力下降，最终失明。虽然神经胶质细胞和免疫反应与 青光眼，对其在视力丧失中的潜在作用知之甚少。反应性星形胶质细胞 越来越多的人显示出在传统的病理读数之前就出现了广泛的神经退行性变 疾病，包括青光眼。我们和其他人报道的反应性星形胶质细胞的一个子集 神经毒性。这些神经毒性反应性星形胶质细胞存在于人类神经变性区域。 多种老年病患者的死后组织，以及急性损伤后视网膜中的组织 在珠状阻塞的青光眼模型中，RGC轴突和慢性视网膜变性。防止地层形成 神经毒性反应性星形胶质细胞可防止神经元死亡，而备用神经元是电生理的 因此，在损伤后和疾病中仍具有潜在的再生价值。 我们现在报道，这些反应性星形胶质细胞分泌一种强有力的神经毒性脂质，特别是长链游离脂肪。 酸，在体外和体内都会导致神经元死亡。阻断参与有毒物质产生的酶 星形胶质细胞中的脂类Elovl1保留了神经元的数量。总而言之，这些发现突出了反应性的一个子集 星形胶质细胞是眼部慢性神经退行性疾病中RGC死亡的驱动因素。在这里，我们将调查 反应性星形胶质细胞衍生毒性脂在确定反应性星形胶质细胞发生时间和机制中的作用 在急性和慢性眼睛损伤期间，导致视网膜中RGC SoMAS的死亡。我们将重点关注三个方面 广泛的研究问题：星形胶质细胞是否需要PERK-ATF3通路来驱动神经细胞死亡 有毒的脂类？阻断神经毒性反应性星形胶质细胞能保护神经元功能和视力吗？ 在青光眼的小鼠模型中？对神经元易感性的要求是什么？ 星形胶质细胞诱导的细胞死亡？我们将使用小鼠模型来确定视神经轴突的维护 反应性星形胶质细胞释放的神经毒性脂缺乏结合视觉变化的研究 同时使用野生型和毒性脂质缺乏小鼠来确定靶向反应性是否为青光眼小鼠的视力 星形胶质细胞可以保护视力。我们还将研究PERK-ATF3介导的单个组件 脂凋亡途径--反应性星形胶质细胞分泌毒性脂导致死亡的一种可能机制 神经元。 这项提案将研究一种在青光眼期间保持视力的新方法。它将提供第一个 计算星形胶质细胞反应性、RGC健康、视力和丘脑突触连接的时间.

PROJECT SUMMARY Glaucoma is a neurodegenerative disease of aging that features the death of retinal ganglion cell neurons (RGCs) in the retina, often as a result of prolonged increases in intraocular pressure. This cell death leads to a decrease in visual acuity and ultimately blindness. While glial and immune responses have been associated with glaucoma, little understood about their potential causative role in loss of vision. Reactive astrocytes are increasingly shown to appear well before traditional pathological readouts of a wide range of neurodegenerative diseases, including glaucoma. One subset of reactive astrocytes reported by us and others as putatively neurotoxic. These neurotoxic reactive astrocytes are present in regions of neurodegeneration in human postmortem tissue from patients with multiple diseases of aging, as well as in the retina following acute injury to RGC axons and in a chronic retinal degeneration in a bead occlusion model of glaucoma. Preventing formation of neurotoxic reactive astrocytes prevents death of neurons, and spared neurons are electrophysiologically functional and thus still have potential value for regeneration following injury and in disease. We now report that these reactive astrocytes secrete a potent neurotoxic lipid, specifically long-chain free fatty acids, that induce death of neurons, both in vitro and in vivo. Block of the enzyme involved in production of toxic lipids, Elovl1, in astrocytes preserves neuron numbers. Together, these findings highlight a subset of reactive astrocytes as drivers of RGC death in a chronic neurodegenerative disease of the eye. Here we will investigate the role of reactive astrocyte-derived toxic lipids to determine the timing and mechanism of reactive astrocytes in driving death of RGC somas in the retina, during acute and chronic injury to the eye. We will focus on three broad research questions: is the PERK-ATF3 pathway required to drive neuron cell death by astrocyte toxic lipids? Does blocking neurotoxic reactive astrocytes preserve neuronal function and visual acuity in a mouse model of glaucoma? And what is the requirement for neuronal susceptibility prior to astrocyte-induced cell death? We will determine maintenance of optic nerve axons using a mouse model deficient for neurotoxic lipids released by reactive astrocytes in combination with investigating changes in visual acuity in glaucomatous mice using both wildtype and toxic lipid-deficient mice to determine if targeting reactive astrocytes can preserve vision. We will also investigate individual components of the PERK-ATF3 mediated lipoapoptosis pathway – a putative mechanism by which reactive astrocyte secreted toxic lipids drive death of neurons. This proposal will investigate a novel approach to maintain vision during glaucoma. It will provide for the first time a connection between astrocyte reactivity, RGC health, visual acuity, and thalamic synaptic connections.