Stimulating Retina Regeneration from Muller Cells in Progressive Retinal Degenerations

遗传性视网膜变性(IRD)导致神经元进行性和永久性死亡。在……里面 然而，最近几年，我们对视网膜内源性干细胞的了解开启了 刺激IRDS患者失去的神经元再生的可能性。莱伯氏病 先天性黑便畸形(LCA)、Bardet-Biedl综合征和视网膜色素变性是最常见的 常见的IRD类型。CEP290的突变是LCA最常见的原因之一，而 BBS2基因突变导致BBS，EYS基因突变导致RP。我们展示了 带有CEP290、bbs2或EYS基因突变的斑马鱼经历了一个渐进的锥体 伴有视杆功能障碍的退行性变。与哺乳动物不同，斑马鱼具有先天的能力 当视网膜神经元受损或丢失时，它们会再生。为了应对视网膜损伤，斑马鱼 表现出强大的再生丢失神经元的能力，包括光感受器。视网膜损伤 导致生长因子和炎性细胞因子的释放，从而触发Müler胶质细胞分裂和 产生多能的视网膜前体细胞，使丢失的神经元再生。这一过程的核心是 涉及STAT3激活的重新编程事件。而健壮的再生发生在 急性损伤，来自文献和初步数据的证据表明再生并不 发生在具有遗传性视网膜退化形式的斑马鱼中，例如CEP290-/-、bbs2-/-或Eys-/-突变。这些观察结果表明，穆勒神经胶质细胞对急性形式和遗传性形式的反应不同 只有当视网膜损伤的程度超过 时间窗口内的“损害阈值”。在斑马鱼的退化突变体中 视杆祖细胞广泛增殖。然而，米勒胶质细胞是锥体的来源 祖细胞，不能繁殖。利用已知的有关再生的机制 斑马鱼的急性视网膜损伤，我们将测试这些信号通路的组件，以确定 它们在这些光感受器退化突变体的Müler细胞中被激活。特别是，我们将 关注汇聚激活STAT3的途径。RNAseq在纯化的马勒神经胶质细胞上的应用 变性突变体，我们将研究变性和炎症如何改变转录组 穆勒神经胶质细胞。最后，我们将使用药理学和遗传学方法来抑制免疫细胞 了解小胶质细胞和巨噬细胞在退化和再生中的作用。 了解多发性斑马鱼疾病视网膜再生的机制 模型将产生新的假设，最终可以转化为患有视网膜的人类 退行性疾病。

Inherited retinal degenerations (IRDs) result in the progressive and permanent death of neurons. In recent years, however, our knowledge of endogenous stem cells in the retina has opened the possibility of stimulating regeneration of lost neurons in patients suffering from IRDs. Leber's Congenital Amaurosis (LCA), Bardet-Biedl Syndrome, and Retinitis Pigmentosa are among the most common form of IRDs. Mutations in CEP290 are one of the most common causes of LCA, while mutations in BBS2 contribute to BBS and mutations in the EYS gene cause RP. We demonstrate that zebrafish with mutations in the either cep290, bbs2, or eys genes undergo a progressive cone degeneration with evidence of rod dysfunction. Unlike mammals, zebrafish have the innate ability to regenerate retinal neurons when they are damaged or lost. In response to retinal injury, zebrafish exhibit a robust capability of regenerating lost neurons, including photoreceptors. Retinal damage causes release of growth factors and inflammatory cytokines that trigger Müller glia to divide and generate multipotent retinal progenitor cells that regenerate lost neurons. Central to this process is a reprogramming event that involves activation of Stat3. While robust regeneration occurs following acute injury, evidence from the literature and preliminary data indicate that regeneration does not occur in zebrafish with inherited forms of retinal degeneration, such as the cep290-/-, bbs2-/-, or eys-/- mutants. These observations suggest that Müller glia respond differently to acute vs. inherited forms of retinal injury and that regeneration is only triggered when the degree of retinal injury crosses a “damage threshold” within a temporal window. In zebrafish degeneration mutants there is widespread proliferation of rod progenitor cells. However, Müller glia, which are the source of cone progenitors, fail to proliferate. Using what is known about mechanisms involved in regeneration after acute retinal injury in zebrafish, we will test components of these signaling pathways to determine if they are activated in Müller cells of these photoreceptor degeneration mutants. In particular, we will focus on pathways that converge to activate Stat3. Using RNAseq on purified Muller glia from these degeneration mutants, we will investigate how degeneration and inflammation alter the transcriptome of Muller glia. Finally, we will use pharmacological and genetic approaches to suppress immune cell activity and understand the role of microglia and macrophages on degeneration and regeneration. Understanding the mechanisms that underpin retinal regeneration in multiple zebrafish disease models will generate novel hypotheses that can ultimately be translated into humans with retinal degenerative diseases.