Mechanisms of RPE dysfunction in macular degenerations-DEIA Supplement

补体系统控制着体内平衡和炎症过程之间的平衡。虽然 补体活性异常与黄斑变性密切相关，抑制这一途径有 在阻止视力丧失方面没有成功。到目前为止，治疗方法主要集中在完全抑制。 对细胞外补体活性的研究，对补体蛋白如何调节视网膜健康的见解有限 和疾病。这在针对补体蛋白C3的方法中尤为明显，补体蛋白C3是核心效应器 补体系统的分子，在视网膜中发挥上下文相关的作用。反击 C3只在细胞外空间起作用的传统观点，我们小组最近的研究发现 细胞内C3激活作为调节视网膜色素上皮(RPE)健康的新机制， 黄斑变性的主要损伤部位。在应激或疾病的RPE中，摄取和蛋白分解增加 C3产生生物活性C3a(“细胞内C3激活”)。C3a进而激活mTOR，一种主控 细胞健康的调节剂。慢性mTOR激活对细胞健康有害，因为它可以重新编程细胞 新陈代谢和细胞命运的决定。基于这些令人兴奋的研究，我们假设异常的细胞内 补体激活可能通过破坏RPE的动态平衡来推动疾病的病理。我们建议 细胞内C3a活性失调的机制、机制和后果的分子解剖 RPE，并确定潜在的治疗干预点，以阻止这种级联反应。我们会识别手机 导致病变RPE细胞内C3a生成增加的机制(目标1)；调查 C3a通过其同源受体C3aR的信号动力学(Aim 2)；并确定持续的C3a-C3aR如何 信号会破坏RPE动态平衡和视网膜功能(目标3)。我们将利用我们的专业知识在创新的高 速度和超分辨率活细胞成像和疾病的小鼠模型获得前所未有的空间和 细胞内C3激活的时间信息及其对视网膜健康的影响。这些研究将 帮助开发一个统一的模型，将AMD的多种特征联系起来，包括胆固醇积累， 补体激活、代谢缺陷和RPE去分化。确定分子机制， 增加细胞内C3的激活将有助于设计保护RPE健康的精确疗法 以及终生的视网膜功能。

The complement system controls the balance between homeostatic and inflammatory processes. Although abnormal complement activity is strongly associated with macular degenerations, inhibiting this pathway has been unsuccessful in halting vision loss. To date, therapeutic approaches have focused on complete inhibition of extracellular complement activity, with limited insight into how complement proteins modulate retinal health and disease. This is particularly evident in approaches targeting the complement protein C3, the core effector molecule of the complement system, which plays context-dependent roles in the retina. Countering the conventional view of C3 acting solely in the extracellular space, recent studies from our group have identified intracellular C3 activation as a novel mechanism that modulates health of the retinal pigment epithelium (RPE), a primary site of injury in macular degenerations. In stressed or diseased RPE, increased uptake and proteolysis of C3 generates biologically active C3a (“intracellular C3 activation”). C3a in turn activates mTOR, a master regulator of cell health. Chronic mTOR activation is detrimental to cell health because it can reprogram cellular metabolism and cell fate decisions. Based on these exciting studies, we hypothesize that abnormal intracellular complement activation could drive disease pathology by compromising RPE homeostasis. We propose to molecularly dissect the machinery, mechanisms, and consequences of dysregulated intracellular C3a activity in the RPE, and identify potential points of therapeutic intervention to halt this cascade. We will identify the cellular machinery responsible for increased intracellular C3a generation in diseased RPE (Aim 1); investigate the dynamics of C3a signaling via its cognate receptor C3aR (Aim 2); and determine how persistent C3a-C3aR signaling disrupts RPE homeostasis and retinal function (Aim 3). We will use our expertise in innovative high- speed and super-resolution live-cell imaging and mouse models of disease to gain unprecedented spatial and temporal information about intracellular C3 activation and its consequences for retinal health. These studies will aid the development of a unified model that links multiple features of AMD, including cholesterol accumulation, complement activation, metabolic deficits and RPE dedifferentiation. Identifying molecular mechanisms that underlie increased intracellular C3 activation will aid the design of precision therapeutics to safeguard RPE health and retinal function over a lifetime.