微环境失衡与重塑在感光细胞死亡中的调控机制和干预研究

Death of photoreceptor is the common cause of blindness secondary to various fundus diseases. The retinal pigment epithelium (RPE) cells serve as key support cells and form a functional complex with the photoreceptors that maintain the homeostasis of the local microenvironment. Previous study of our group have found that the injury of RPE cells could activate inflammation processes, thus leading to retinal microenvironment imbalance. Meanwhile, as the key trigger, mitochondria response to the microenvironment stress, which activates and mediates photoreceptor cell injury and death process. Thus, our study would focus the regulatory mechanisms of the photoreceptors’ survival microenvironment. First, we intend to study the role of NLRP3/inflammasome and its activation mechanisms in RPE proinflammatory response to clarify the mechanism of microenvironment imbalance induced by proinflammatory reactions of RPE. We would further investigate the potential risk factors to illustrate the underlying injury/death signal transduction mechanisms after microenvironment imbalance in photoreceptors. Finally, we would target the NLRP3 to maintain the immune regulating function of RPE cells, by introducing the combinational therapy of mitochondria-targeted photoreceptor cells pressure stress level control along with the NLRP3-targeted strategy. The results of our study might elucidate the key molecular mechanism of retinal damage resulting from RPE-photoreceptor functional complex impairment and microenvironment imbalance. Our results could provide novel photoreceptors protective strategy by remodeling the microenvironment homeostatic restoration.

感光细胞死亡是多种眼底病致盲的共同病理改变，机制复杂且缺乏有效干预方法。RPE作为支持细胞，与感光细胞组成“结构功能复合体”，维持局部微环境稳态。课题组前期发现RPE细胞损伤后激活炎症反应，导致感光细胞生存微环境失衡；同时线粒体介导了感光细胞对微环境失衡的应激反应。由此，本课题拟以调控感光细胞生存微环境为核心，首先研究RPE细胞促炎反应中NLRP3/炎症小体的作用及其活化机制，初步阐明RPE细胞促炎反应导致微环境失衡的启动机制；进一步确认参与微环境危险因子，阐明微环境失衡后启动感光细胞损伤/死亡信号的转导机制；最后探讨以NLRP3为靶点，干预RPE细胞免疫调节功能，同时联合以线粒体为靶点，干预感光细胞压力应激水平的视网膜神经保护新策略。研究结果将揭示感光细胞复合体损伤、微环境稳态失衡相互作用导致视网膜损伤的关键分子机制，为建立通过恢复微环境稳态、保护感光细胞的新策略奠定理论基础和实验依据。

感光细胞死亡是多种眼底病致盲的共同病理改变，机制复杂且缺乏有效干预方法。RPE作为支持细胞，与感光细胞组成“结构功能复合体”，维持局部微环境稳态。本课题聚焦“感光细胞-RPE结构功能复合体”损伤导致感光细胞生存微环境失衡的病理机制，首先通过回顾性分析临床数据，发现病理沉积物是导致AMD进展及RPE细胞损伤的始动因素，在此基础上，结合组学分析并辅以细胞和动物实验验证，阐明了损伤后病理沉积物的重要成分淀粉样蛋白β（Aβ）在病理条件下可激活RPE自噬，SIRT6 -自噬途径可能是调控RPE炎症反应的分子“开关”， m6A mRNA表观转录组微阵列分析及RNA-seq分析发现病理沉积的Aβ可通过表观遗传调控的方式激活NLRP3炎症小体通路，引起RPE损伤，进一步促进眼底炎性微环境形成。对临床样本的蛋白组学分析表明失衡的免疫微环境改变巨噬细胞的极性，进一步导致眼底微环境的失衡，并触发炎性正反馈回路进一步促进RPE和眼底免疫细胞的活化；基于细胞及动物损伤模型，课题组研究发现微环境失衡是感光细胞死亡的始动因素，而GSDMD介导的视网膜原为免疫细胞激活引起的细胞焦亡是其主要死亡形式之一，同时xCT介导的氧化应激损伤可导致夹中线粒体压力引起感光细胞凋亡是另外一种死亡形式，初步阐明微环境损伤后感光细胞死亡的关键病理机制。最后，我们靶向视网膜微环境失衡引起结构功能复合体损伤，以多靶点干预及基因治疗研究为策略，实现3项基因治疗的IIT研究。我们的研究结果揭示感光细胞复合体损伤、微环境稳态失衡相互作用导致视网膜损伤的关键分子机制，并以此为基础，开发出改善微环境稳态、治疗视网膜变性的新策略，具有重要的意义。