Innate immune system regulation of retinal regeneration

项目总结 退行性视力障碍是由视网膜细胞的丧失引起的。在斑马鱼，视网膜Müler胶质(MG)动作 作为干细胞，生成MG来源的祖细胞(MGPC)，以取代丢失的视网膜细胞。哺乳动物 Mg/MGPC也能产生新的视网膜神经元，然而，增殖能力有限，疾病- 相关的细胞类型(例如，光感受器)很少产生。我们的目标是理解为什么再生能源 与可再生物种(如斑马鱼)相比，MG/MGPC在哺乳动物中的潜力有限。 在斑马鱼中，广泛的视网膜细胞丧失会触发“发育”再生，产生所有主要的视网膜细胞 上课。相反，选择性视网膜细胞丢失会导致“偏向于命运”的过程，其中MGPC导致 丢失的单元格类型。然而，MG如何感觉到损失的程度尚不清楚。因为免疫系统起着至关重要的作用 在视网膜再生过程中，我们研究了小胶质细胞活性对斑马鱼MG激活的影响。 我们观察到，MG干细胞激活需要小胶质细胞，免疫抑制可以抑制或 根据处理时机的不同，增强再生动力学。我们假设小胶质细胞的反应性 水平根据视网膜细胞丢失的程度、持续时间和/或特异性进行调整，以协调MG 激活、MGPC增殖率和脂肪决定了所发生的损伤类型。测试我们的 假设，在这里我们建议结合一种改进的靶向细胞消融系统， 可持续的、选择性的视网膜细胞丢失，具有免疫细胞类型标记的资源/方法，活体内 时间流逝成像、谱系追踪和单细胞转录。具体地说，我们将定义范围如何 视锥感光细胞或视网膜神经节细胞丢失影响的持续时间(目标2)和特异性(目标3) 免疫细胞反应性和视网膜再生。这些实验将用于确定特定免疫的角色 在斑马鱼的再生过程中，细胞亚型对MGPC的增殖和细胞命运起着决定作用。

PROJECT SUMMARY Degenerative vision disorders are caused by the loss of retinal cells. In zebrafish, retinal Müller glial (MG) act as stem cells, generating MG-derived progenitor cells (MGPCs) which replace lost retinal cells. Mammalian MG/MGPCs can also produce new retinal neurons, however, proliferative capacity is limited and disease- relevant cell types (e.g., photoreceptors) are rarely generated. Our goal is to understand why the regenerative potential of MG/MGPCs are limited in mammals in comparison to a regenerative species (i.e. zebrafish). In zebrafish, widespread retinal cell loss triggers “developmental” regeneration, producing all major retinal cell classes. Conversely, selective retinal cell loss results in a “fate-biased” process where MGPCs give rise to the lost cell type. How MG sense the extent of loss, however, is unknown. As the immune system plays critical roles during retinal regeneration, we examined the impact of microglia reactivity on MG activation in zebrafish. We observed that microglia are required for MG stem cell activation and that immunosuppression can inhibit or enhance regeneration kinetics depending on the treatment timing. We hypothesize that microglia reactivity levels scale to the extent, duration, and/or specificity of retinal cell loss in order to coordinate MG activation, MGPC proliferation rates and fat decisions to the type of injury incurred. To test our hypothesis, here we propose to combine an improved targeted cell ablation system enabling titratable, sustainable, and selective retinal cell loss with resources/methods for labeling of immune cell types, intravital timelapse imaging, lineage tracing, and single cell transcriptomics. Specifically we will define how the extent (Aim 1), the duration (Aim 2) and specificity (Aim 3) of cone photoreceptor or retinal ganglion cell loss impact immune cell reactivity and retinal regeneration. These experiments will serve to define roles specific immune cell subtypes play in shaping MGPC proliferation and cell fates during regeneration in zebrafish.