Diversity Supplement Mancilla-Aceves June 2021

补体系统控制稳态和炎症过程之间的平衡。虽然 异常的补体活性与黄斑变性密切相关，抑制该途径， 未能成功阻止视力丧失。迄今为止，治疗方法集中于完全抑制 细胞外补体活性，对补体蛋白如何调节视网膜健康的了解有限 和疾病这在靶向补体蛋白C3（核心效应物）的方法中尤其明显。 补体系统的分子，其在视网膜中起依赖于环境的作用。打击 传统观点认为C3仅在细胞外空间起作用，我们小组最近的研究已经确定 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。在应激或患病的RPE中， 产生生物活性的C3 a（“细胞内C3活化”）。C3 a反过来激活mTOR，一个主细胞 调节细胞健康。慢性mTOR激活对细胞健康有害，因为它可以重新编程细胞 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 补体激活可通过损害RPE体内平衡来驱动疾病病理。我们建议 从分子上剖析了细胞内C3 a活性失调的机制、机制和后果， RPE，并确定潜在的治疗干预点，以阻止这种级联反应。我们会识别出 在患病的RPE中负责增加细胞内C3 a产生的机制（目的1）;研究 C3 a信号通过其同源受体C3 aR的动力学（目的2）;并确定如何持久C3 a-C3 aR 信号传导破坏RPE稳态和视网膜功能（Aim 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，以获得前所未有的空间和 关于细胞内C3激活及其对视网膜健康后果的时间信息。这些研究将 有助于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。识别分子机制， 细胞内C3激活增加的基础将有助于设计精确的治疗方法来保护RPE健康 和视网膜功能。

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.