Interdependence of Antimicrobial and Pro-inflammatory Activities Mediated byS100A12 in the Innate Immune Response

人类先天免疫系统由几个组成部分组成，这些组成部分协同工作， 发病机制作为先天性免疫系统的一个成熟成员，已知S100 A12可以进行免疫调节。 通过螯合锌离子的抗微生物活性。这种隔离限制了病原体对Zn 2+的接触， 是它们繁殖的关键养分。此外，在感染过程中，S100 A12与膜相互作用， 受体如晚期糖基化终末产物受体（AGEs），以启动促炎性 信号级联虽然已知参与抗微生物和促炎活性， S100 A12的相互作用模式，特别是与膜受体的相互作用模式尚不清楚。我们的目标是 建议是表征S100 A12的金属结合性能，使其能够进行抗菌 活动和发展的S100 A12与E2的相互作用的原子尺度的理解。我们建议， 相互作用是由其抗微生物活性引发的，这使我们能够假设， S100 A12的炎症活性是相互依赖的。 我们的研究表明，通过Zn 2+螯合的抗微生物活性，S100 A12经历了自- 组装导致低聚物的形成。我们还表明，这种自组装是依赖于 S100 A12的浓度。这些结果，结合文献中的报告，证明了 血清和人体组织中存在寡聚S100 A12物质，使我们能够提出一个方案， S100 A12在免疫系统中的作用该模型提出S100 A12浓度依赖性 细胞中的促炎作用是在其抗微生物反应后启动的，从而建立了一个 其抗菌活性和促炎活性之间的相关性。为了验证我们的假设，我们提出了 以下具体目的是表征S100 A12抗微生物功能及其低聚物的作用：（i） 低聚S100 A12组装体中过渡金属离子的配位环境的表征;（ii） 鉴定S100 A12的寡聚化机制;和（iii）确定S100 A12的寡聚化的依赖性。 S100 A12与聚乙烯的相互作用模式和低聚顺序。 这些拟议中的研究将提供S100 A12-B12的原子和分子水平的快照。 体外相互作用，这将为这些细胞之间的相互作用模式提供指导 体内成分。与我们的长期目标一致，即揭示金属依赖过程的原子细节 在人类免疫反应中，这一提议将提供对金属依赖性自我的作用的见解， S100 A12的组装。这些研究将增强对S100 A12功能的理解，并提供 新疗法设计的基础。

The human innate immune system is composed of several components that work in conjunction to curtail pathogenesis. As a well-established member of the innate immune system, S100A12 is known to conduct antimicrobial activities via sequestration of zinc ions. This sequestration limits the pathogen's access to Zn2+, a critical nutrient for their proliferation. Furthermore, during infection, S100A12 interacts with membrane receptors such as the receptor for advanced glycation end products (RAGE) to initiate a pro-inflammatory signaling cascade. Although known to participate in both antimicrobial and pro-inflammatory activities, the mode of interaction of S100A12, particularly with the membrane receptors, is not known. Our goal in this proposal is to characterize the metal binding properties of S100A12 that allow it to perform antimicrobial activities and develop an atomic scale understanding of interaction of S100A12 with RAGE. We propose that this interaction is initiated by its antimicrobial activities allowing us to hypothesize that the antimicrobial and pro- inflammatory activities of S100A12 are interdependent. Our studies demonstrate that by the antimicrobial activity of Zn2+ sequestration, S100A12 undergoes self- assembly leading to the formation of oligomers. We also show that this self-assembly is dependent on the concentration of S100A12. These results, in conjunction with reports in the literature demonstrating the presence of oligomeric S100A12 species in blood serum and human tissues, have allowed us to propose a scheme describing the role of S100A12 in the immune system. This model proposes S100A12 concentration dependent pro-inflammatory actions in cells that are initiated upon its antimicrobial responses, thereby establishing a correlation between its antimicrobial and pro-inflammatory activities. To test our hypothesis, we propose the following specific aims to characterize S100A12 antimicrobial functions and the role of its oligomers: (i) characterization of the coordination environment of transition metal ions in oligomeric S100A12 assemblies; (ii) identification of the mechanism of oligomerization of S100A12; and (iii) determination of the dependence of the mode of interaction of S100A12 with RAGE and the order of oligomerization. These proposed studies will provide atomic- and molecular-level snapshots of the S100A12-RAGE interactions in vitro, which will provide guidance for the mode of the interaction between these cellular components in vivo. In line with our long-term goal to unravel atomistic details of metal-dependent processes in the human immune response, this proposal will provide insights into the role of metal dependent self- assembly of S100A12. These studies will enhance the understanding of the functioning of S100A12 and provide basis for the design of novel therapeutics.