Cell Biology of Astrocytes in Optic Nerve Head

项目总结 青光眼的特征是视网膜神经节细胞进行性丧失。降低死亡率的药物 眼压是青光眼药物治疗的主要手段，但效果不佳。 在所有情况下。因此，新的治疗方法将是受欢迎的。 许多证据表明，视神经头是神经节细胞轴突的最初损害点 青光眼。在这个解剖位置，星形胶质细胞网络形成了直接的细胞环境 轴突。视神经受到侮辱后，视神经头中的星形胶质细胞就会发生反应。 我们研究了神经挤压后视神经头部星形胶质细胞反应的时间进程。 在形态和基因表达水平上。我们还研究了星形胶质细胞的形态。 自发性青光眼的DBA/2J小鼠品系。将DBA/2J小鼠与一种 在单个星形胶质细胞中表达GFP，从而对反应性星形胶质细胞进行显微镜观察 很简单。我们的发现之一是，在神经节细胞退化的任何迹象变得明显之前 视网膜，一些星形胶质细胞长出新的纵向突起，形成板层后轴突束。我们是 现在要研究推动这些过程增长的机制和它们的功能。 我们认为，星形胶质细胞的反应性，至少在其早期阶段，是一种有益的反应，目的是 保护神经节细胞和它们的轴突。治疗青光眼的一种可能的方法是 增强星形胶质细胞的早期反应。因此，我们建议研究 支配早期星形胶质细胞反应性的视神经。我们比较了差异调控的基因 在我们自己的微阵列筛选中(使用视神经挤压)与最近研究中报道的那些 来自其他实验室，使用DBA/2J小鼠或巩膜外静脉注射高眼压模型 老鼠。我们发现了在DBA/2J早期上调的信号分子和转录因子 小鼠和神经挤压后，因此似乎参与调节星形胶质细胞的反应性在 青光眼和外伤性损伤后。这些基因中的大多数在巩膜上静脉中也上调。 注塑模型。我们的候选信号分子是骨形态发生蛋白1和2， 白血病抑制因子)、分泌型磷蛋白1(骨桥蛋白)、Lipocalin 2和转化 生长因子β1和转录因子TCF19，转化生长因子β诱导因子同源盒1，Run-1。 相关转录因子1和2，以及E2f8。我们将研究他们在三个模型中的参与情况 青光眼，视神经挤压后。为此，我们将利用方法学上的进步。 在第一次授权期，即AAV2/9高效转染视神经头星形胶质细胞期间， 分析从视神经头分离的形态保存完好的星形胶质细胞的能力， 以及一种在星形胶质细胞中以“活高尔基染色”的方式表达绿色荧光蛋白的小鼠品系。

Project summary The characteristic feature of glaucoma is a progressive loss of retinal ganglion cells. Drugs that lower the intraocular pressure are the mainstay of pharmaceutical therapy of glaucoma, but they are not effective in all cases. New therapeutic approaches would therefore be welcome. Much evidence points to the optic nerve head as the point of initial insult to ganglion cell axons in glaucoma. In this anatomical location, a meshwork of astrocytes forms the direct cellular environment of the axons. Following an insult to the optic nerve, the astrocytes in the optic nerve head become reactive. We have studied the time course of astrocyte reactivity in the optic nerve head after nerve crush morphologically and on the level of gene expression. We also studied astrocyte morphology in the DBA/2J mouse line that develops glaucoma spontaneously. DBA/2J mice were crossed with a strain that expresses GFP in individual astrocytes, thus making the microscopic observation of reactive astrocytes easy. One of our findings was that, before any signs of ganglion cell degeneration become obvious in the retina, some astrocytes grow new, longitudinal processes into the retrolaminar axon bundles. We are now going to study the mechanisms that drive the growth of these processes and their function. We believe that astrocyte reactivity, at least in its early phase, is a beneficial response that aims to protect ganglion cells and their axons. A possible therapeutic approach to glaucoma would be to enhance the early astrocytic response. We therefore propose to study the regulatory mechanisms in the optic nerve that govern early astrocyte reactivity. We compared the genes that are differentially regulated in our own microarray screen (using optic nerve crush) with those that were reported in recent studies from other laboratories using DBA/2J mice or the episcleral vein injection model of ocular hypertension in rats. We identified signaling molecules and transcription factors that were up-regulated early in DBA/2J mice and after nerve crush and therefore appear to be involved in regulating astrocyte reactivity both in glaucoma and after traumatic injury. Most of these genes are also up-regulated in the episcleral vein injection model. Our candidates are the signaling molecules Bone Morphogenetic Proteins 1 and 2, Leukemia Inhibitory Factor), Secreted Phosphoprotein 1 (osteopontin), Lipocalin 2, and Transforming Growth Factor beta 1; and the transcription factors Tcf19, TGFβ-Induced Factor Homeobox 1, Runt- Related Transcription factors 1 and 2, and E2f8. We will study their involvement in three models of glaucoma, and after optic nerve crush. For this purpose, we will make use of methodological advances during the first grant period, namely the efficient transfection of optic nerve head astrocytes by AAV2/9, the ability to analyze dissociated astrocytes with well-preserved morphology from the optic nerve head, and a mouse strain that expresses GFP in astrocytes in the manner of a “live Golgi stain”.