Elucidating the role of DNA methyltransferases in epigenetic regulation of retinal regeneration in zebrafish

项目摘要 根据国家眼科研究所的数据，目前有超过1200万美国人患有 影响视网膜的疾病。目前，治疗试图减少视网膜死亡或 替代失去的神经元已经遇到了有限的成功，突出了替代品的需要 解决这个问题的方法。斑马鱼正在成为一种越来越受欢迎的研究模型 基于干细胞的组织再生机制。为了应对大面积视网膜损伤， 斑马鱼能够完全再生视网膜。这是通过归纳 Müller神经胶质细胞进行不对称分裂产生祖细胞池 这些细胞可以再生视网膜上所有类型的细胞，但没有观察到神经胶质瘢痕的证据。 在哺乳动物物种中。虽然斑马鱼具有非凡的组织再生能力， 多年来，我们对哺乳动物和哺乳动物之间的比较生物学的理解 硬骨鱼对视网膜损伤的反应仍然知之甚少。目前，视网膜病变的研究 斑马鱼的再生主要集中在识别信号通路上， 参与视网膜再生的单个基因。这些通路的表观遗传协调， 然而，在斑马鱼中仍有待研究。DNA甲基转移酶（Dnmts）已被 在哺乳动物中进行了广泛的研究，并已被确定为在体内平衡中至关重要。 维持成体干细胞过程，如造血干细胞发育。的 斑马鱼表观遗传调节因子的有限文献表明，硬骨鱼类似乎利用 与哺乳动物物种相同的表观遗传调节机制，斑马鱼Dnmts 与哺乳动物Dnmts具有相当大的序列同源性。据了解， 在斑马鱼视网膜损伤后，存在初始的整体DNA低甲基化， 随后随着祖细胞池开始分化DNA甲基化增加， 这表明表观遗传景观在这些过程中的重要性。与 在这个提议中计划的实验中，我们的目标是确定Dnmts在协调 斑马鱼成年视网膜再生的过程，目的是阐明途径 在Müller胶质源性祖细胞中在表观遗传水平上受到调节。我们还计划开发 这是一种新工具，将成为斑马鱼群落研究的重要补充 特定基因的靶向表观遗传调节的后果。这些拟议的研究将 阐明靶向治疗方法的候选基因以识别和“解锁”途径 在哺乳动物系统中，表观遗传沉默，为未来的研究开辟了新的途径 在再生医学领域。

Project Abstract According to the National Eye Institute, there are currently over 12 million Americans suffering from diseases affecting the retina. To present, therapeutic attempts to reduce retinal death or replace lost neurons have been met with limited success, highlighting the need for an alternative approach to this problem. The zebrafish is becoming an increasingly popular model to study mechanisms of stem-cell based tissue regeneration. In response to extensive retinal injury, zebrafish are able to completely regenerate the retina. This is accomplished through the induction of Müller glial cells which undergo an asymmetric division to generate a pool of progenitor cells that go on to regenerate all cell types of the retina with no evidence of the glial scarring observed in mammalian species. While the remarkable capacity of the zebrafish to regenerate tissues has been known for years, our understanding of the comparative biology between mammalian and teleost responses to retinal damage remains poorly understood. To present, studies of retinal regeneration in the zebrafish have largely focused on identifying signaling pathways and individual genes involved in retinal regeneration. The epigenetic orchestration of these pathways, however, remains to be investigated in the zebrafish. DNA methyltransferases (Dnmts) have been studied extensively in mammals and have been identified as critical in the homeostatic maintenance of adult stem cell processes such as hematopoietic stem cell development. The limited literature of epigenetic regulators in zebrafish reveals that teleost species appear to utilize the same mechanisms of epigenetic regulation as mammalian species, with zebrafish Dnmts baring considerable sequence homology to mammalian Dnmts. It is known that immediately following retinal injury in the zebrafish there is an initial global DNA hypomethylation and subsequent increase in DNA methylation as the pools of progenitor cells begin to differentiate, indicating the importance of the epigenetic landscape during these processes. With the experiments planned in this proposal, we aim to identify the role of Dnmts in orchestrating the process of adult retinal regeneration in the zebrafish, with the goal of elucidating pathways regulated in Müller glial derived progenitor cells at the epigenetic level. We also plan to develop a new tool that will be an important addition to the zebrafish community for investigation of the consequences of targeted epigenetic modulation of specific genes. These proposed studies will illuminate candidate genes for targeted therapeutic approaches to identify and “unlock” pathways in mammalian systems that are epigenetically silenced, opening new avenues for future studies in the field of regenerative medicine.