Muller glia and neuronal regeneration in the retina

描述（由申请人提供）：神经胶质细胞神经再生的可能性最近获得了可信度和普及。我们先前已经表明，出生后鸡视网膜中的大量Muller神经胶质细胞可以重新进入细胞周期，去分化，表达通常由视网膜祖细胞表达的转录因子，并产生一些新的神经元（Fischer和Reh，2001 a）。我们发现，Muller神经胶质细胞可以响应于急性损伤（Fischer和Reh，2001 a）或响应于在没有损伤的情况下胰岛素和FGF 2（成纤维细胞生长因子2）的组合（Fischer等人，2002年b）。因此，米勒神经胶质细胞具有作为视网膜内神经再生的细胞来源的潜力。然而，调节Muller神经胶质细胞重新进入细胞周期、成为祖细胞和分化为神经元的能力的机制仍然未知且未被探索。支持这一提议的具体假设是MAP激酶、Jak/STAT和Notch信号通路调节Muller胶质细胞对视网膜损伤的不同反应。根据初步数据，我们将检验以下假设。(1)MAP激酶途径促进神经胶质去分化和增殖，并抑制反应性神经胶质增生的方面，如GFAP（胶质细胞酸性蛋白）表达。(2)睫状神经营养因子（CNTF）/Jak-STAT信号传导促进神经胶质成熟，促进GFAP表达，并抑制神经胶质增殖。(3)Notch介导的信号传导阻止急性损伤视网膜中Muller胶质源性祖细胞的神经元分化(4)成熟、受损的视网膜缺乏祖细胞神经元分化所需的线索。该提案提出了具体目标，并描述了检验上述假设的实验。这些实验产生的数据将提供有价值的信息，关于穆勒神经胶质细胞可用作视网膜内神经再生的来源的可能性。此外，这些数据将为控制神经胶质增生的分泌因子和信号通路以及神经胶质细胞重新进入细胞周期的能力提供新的见解。这些信息不仅可以用于刺激神经再生以治疗威胁视力的视网膜疾病，还可以用于控制可能对视网膜疾病的发病机制有害的神经胶质增生。

DESCRIPTION (provided by applicant): The possibility of neural regeneration from glial cells has recently gained credibility and popularity. We have previously shown that large numbers of Muller glia in the postnatal chicken retina can re-enter the cell cycle, de-differentiate, express transcription factors normally expressed by retinal progenitors, and produce a few new neurons (Fischer and Reh, 2001 a). We found that Muller glia can become retinal progenitor-like cells in response to acute damage (Fischer and Reh, 2001 a) or in response to the combination of insulin and FGF2 (fibroblast growth factor 2) in the absence of damage (Fischer et al., 2002b). Thus, Muller glia hold the potential to act as a cellular source of neural regeneration within the retina. However, the mechanisms that regulate the ability of Muller glia to re-enter the cell cycle, become progenitor cells, and differentiate as neurons remain unknown and unexplored. The specific hypothesis that underlies this proposal is that MAP kinase, Jak/STAT and Notch signaling pathways regulate the different responses of Muller glia to retinal damage. Based on preliminary data we will test the following hypotheses. (1) MAP kinase pathways promote glial de-differentiation and proliferation, and suppress aspects of reactive gliosis such as GFAP (glial fibrillary acidic protein) expression. (2) CNTF (ciliary neurotrophic factor)/Jak-STAT signaling promotes glial maturation, promotes GFAP expression, and suppresses glial proliferation. (3) Notch-mediated signaling prevents neuronal differentiation from Muller glia-derived progenitors in acutely damaged retinas. (4) Mature, damaged retinas lack the cues required for neuronal differentiation of progenitor cells. This proposal provides specific aims and describes experiments to test the above-listed hypotheses. Data produced by these experiments will provide valuable information regarding the possibility that Muller glia can be used as a source of neural regeneration within the retina. In addition, the data will provide new insights into the secreted factors and signaling pathways that control gliosis and the ability of glial cells to re-enter the cell cycle. This information could be applied to not only stimulate neural regeneration to treat sight-threatening diseases of the retina, but also to control gliosis that may be detrimental to the pathogenesis of retinal disorders.