Cell specific roles of the endothelin system in glaucoma-relevant retinal ganglion cell death

青光眼是一种以视网膜神经节细胞(RGC)死亡和视神经为特征的视神经病变 退化。不幸的是，目前还没有专门针对神经退行性变的治疗方法。 确定导致疾病发生和发展的信号通路将是 开发治疗青光眼神经变性的有效药物干预措施。内皮素(EDN) 系统在全身广泛表达，参与生理和病理生理过程。 流程。现在有大量证据表明在人类和动物模型中存在EDN系统 青光眼的症状。EDN系统的操作显著减少了一个遗传性和两个诱导性RGC损失 青光眼模型。此外，EDN信号在视网膜和视神经头中上调 青光眼高眼压模型中RGC死亡或功能障碍的迹象。尽管有潜在的 EDN在青光眼神经退行性变中的重要性及其诱导RGC的分子机制 死亡是完全不确定的。特别是，上游监管机构和下游效应器 EDN系统是未知的。导致很难理解EDN信号如何在 青光眼神经变性是EDN受体Ednra和EDNRB在 视网膜和视神经头的多种细胞类型，包括视网膜节细胞、星形胶质细胞、髓系细胞 (小胶质细胞和巨噬细胞)和壁细胞(周细胞和平滑肌血管细胞)。此外， 已知EDN影响所有这些细胞的方式与观察到的病理反应一致 青光眼。因此，为了了解EDN在青光眼中的信号转导，需要EDN的成分 系统，包括受体和配体，必须在与青光眼相关的细胞中进行系统测试 以表示。在这里，我们将测试这样的假设，即定义EDN系统在RGC死亡中的作用将 确定青光眼发病机制的早期关键信号通路。要做到这一点并达到 定义青光眼相关损伤后EDN信号如何发挥作用，我们将1)定义 EDN诱导RGC死亡所需的RGC，2)决定受体、细胞类型和分子 控制EDN诱导的RGC死亡的途径(S)；3)决定哪些细胞类型和分子途径 负责产生致病的EDN配体。重要的是，此应用程序将重点介绍 EDN系统在单个细胞类型中，有条件地去除EDN成分并进行转录 在单个细胞类型上。总而言之，应用程序中概述的实验对长期存在的 关于EDN在青光眼中作用的假说，并确定各种细胞类型和分子机制 控制青光眼相关的致病EDN信号。鉴于EDN的早期性质和已被证明的作用 青光眼神经退行性变中的信号传递这些实验将确定新的开发靶点 青光眼发病机制早期的神经保护治疗。

Glaucoma is an optic neuropathy characterized by retinal ganglion cell (RGC) death and optic nerve degeneration. Unfortunately, there are no current treatments that specifically target neurodegeneration. Identifying the signaling pathways responsible for disease onset and progression will be an important step in developing effective pharmacologic interventions for glaucomatous neurodegeneration. The endothelin (EDN) system is widely expressed throughout the body and participates in both physiological and pathophysiological processes. There is now a large body of evidence implicating the EDN system in human and in animal models of glaucoma. Manipulation of the EDN system significantly lessens RGC loss in a genetic and two inducible models of glaucoma. Also EDN signaling is upregulated in both the retina and optic nerve head prior to any signs of RGC death or dysfunction in an ocular hypertensive model of glaucoma. Despite the potential importance of EDN in glaucomatous neurodegeneration, the molecular mechanisms of EDN-induced RGC death are completely undefined. In particular, the upstream regulators and the downstream effectors of the EDN system are not known. Contributing to the difficulty in understanding how EDN signaling plays a role in glaucomatous neurodegeneration is the fact that EDN receptors, Ednra and Ednrb, are expressed on numerous cell types in the retina and optic nerve head including RGCs, astrocytes, myeloid derived cells (microglia and macrophages), and mural cells (pericytes and smooth muscle vascular cells). Furthermore, EDN is known to affect all of these cells in ways that are consistent with pathological responses observed in glaucoma. Thus, in order to understand EDN signaling in glaucoma the requirement of components of the EDN system, both receptors and ligands, must be systematically tested in the glaucoma-relevant cells they are expressed in. Here, we will test the hypothesis that defining the role of the EDN system in RGC death will identify early, critical signaling pathways that underlie glaucoma pathogenesis. To accomplish this and to define how EDN signaling functions after glaucoma-relevant insults, we will 1) define the mechanisms within RGCs that are required for EDN-induced RGC death, 2) determine the receptor, cell type, and molecular pathway(s) controlling EDN-induced RGC death, and 3) determine which cell types and molecular pathways are responsible for producing pathogenic EDN ligands. Importantly, this application will focus on the role of the EDN system in individual cell types, conditionally removing EDN components and performing transcriptomics on individual cell types. Together, the experiments outlined in the application critically test a long-standing hypothesis about the role of EDN in glaucoma and identify the various cell types and molecular mechanisms controlling glaucoma-relevant pathogenic EDN signaling. Given the early nature and proven role of EDN signaling in glaucomatous neurodegeneration these experiments will identify novel targets for developing neuroprotective treatments for glaucoma at early stages of disease pathogenesis.