Evaluating the role of protein self-assembly in the innate immune system

随着人类年龄的增长，促炎症细胞因子水平增加，导致慢性炎症状态，称为炎症。炎症是与年龄相关的疾病的一个标志，并会增加老年人的死亡率。炎症发生的分子机制尚未阐明。因此，迫切需要阐明导致持续促炎信号的分子机制，因为这样做将加快预防和治疗与年龄相关的疾病和自体炎症的努力。这项建议的总体目标是确定特定的分子机制是否有助于老年单核细胞的促炎表型。到目前为止收集的数据显示，作为病原体识别受体下游关键节点的多个死亡结构域蛋白是通过核限制组装机制激活的。这种形式的组装具有自我维持的性质，原则上应该允许它们无限期地持续存在，并不断诱导单核细胞产生促炎信号。拟议的目标将解决两个重要的问题：1)蛋白质自组装是否足以在单核细胞中建立和维持促炎状态？2)蛋白质自组装是否与先天免疫细胞在造血水平上的产量和功能下降有关？在这项拟议的研究的F99阶段，研究人员的目标是确定驱动单核细胞持续促炎状态的分子底物。应用新的工具来测量蛋白质在体内自组装的功能，将解决某些死亡结构域蛋白质的组装状态是否在功能上建立单核细胞的促炎状态。在这项拟议的研究的K00阶段，研究人员将确定造血干细胞(HSC)衰退和信号小体形成导致的自我更新受损的潜在机制。具体地说，拟议的实验将确定死亡结构域蛋白自组装是否对HSC进行功能性重新编程，以扭曲预先加载了促炎信号的髓系细胞的产生。为了实现这些目标，研究人员将利用细胞学、生化和基因编辑技术开发和实施新的方法。完成这些目标将确定炎症的分子底物，并揭示有序的蛋白质自组装在信号和细胞分化中的未知作用。这项拟议的工作具有创新性，并将新兴的生物物理概念引入衰老和免疫衰老领域。

As humans age, levels of proinflammatory cytokines increase, leading to a chronic inflammatory state, known as inflammaging. Inflammation is a hallmark of age-related diseases and increases mortality among the elderly. The molecular mechanisms that underlie inflammaging have not yet been elucidated. Therefore, there is an urgent need to elucidate the molecular mechanisms causing persistent proinflammatory signals, as doing so will accelerate efforts to prevent and treat age-related and autoinflammatory diseases. The overall goal of this proposal is to determine if a specific molecular mechanism contributes to the proinflammatory phenotype of aged monocytes. The data gathered so far reveals that multiple Death Domain proteins that function as key nodes downstream of pathogen recognition receptors are activated through a nucleation-limited assembly mechanism. The self-sustaining nature of this form of assembly should in principle allow them to persist indefinitely and continuously induce monocytes for proinflammatory signaling. The proposed aims will address two important questions: 1) Do protein self-assemblies suffice to establish and maintain a proinflammatory state in monocytes? 2) Are protein self-assemblies involved in the declining production and function of innate immune cells at the hematopoiesis level? In the F99-phase of this proposed research, the researcher aims to identify the molecular substrate that drives a persistent proinflammatory state in monocytes. The implementation of novel tools to measure functionality of protein self-assemblies in vivo, will address whether the assembled states of certain Death Domain proteins are functionally establishing a proinflammatory state in monocytes. In the K00-phase of this proposed research, the researcher will identify a potential mechanism of hematopoietic stem cell (HSC) decay and impaired self-renewal caused by signalosome formation. Specifically, the proposed experiments will determine whether Death Domain protein self-assemblies functionally reprogram HSC to skew the production of myeloid cells preloaded with a proinflammatory signature. To achieve these goals, the researcher will develop and implement novel approaches using cytological, biochemical and gene editing techniques. Completion of these aims will identify molecular substrates of inflammaging and reveal an unexplored role of ordered protein self-assemblies in signaling and cell differentiation. The proposed work is innovative and brings emerging biophysical concepts to the aging and immune senescence fields.