The immunological mechanism of PGRNs anti-inflammatory effect - Renewal - 1

项目描述 TNFα/TNFR由于其在促炎性细胞周期的顶点位置而受到最大的关注。 细胞因子级联反应及其在炎症发病机制中的主导地位。TNFR 1主要介导炎症反应， TNFR 2在多种疾病中起保护和抗炎作用。我们的- 对颗粒蛋白前体（PGRN）生长因子结合伴侣的遗传学筛选导致TNFR 2的分离， PGRN结合受体（Tang等人，Science，2011）。值得注意的是，PGRN表现出大约600倍的 与TNFR 2的结合亲和力高于TNFα。在最初的融资期间，我们成功地识别了- 在蛋白质组学筛选中，14-3-3ε是一种重要的细胞内信号分子， TNFR 2复合物响应PGRN刺激。PGRN缺乏会促进炎症的发生- 激活的巨噬细胞（CAM），但抑制抗炎交替激活的巨噬细胞（AAM）极化， 而重组PGRN抑制AAM-CAM，但刺激CAM-AAM转换。此外，本发明还提供了一种方法， 14-3-3ε基因敲除后PGRN对巨噬细胞的调节作用消失。更令人兴奋的是，我们的直接蛋白质-蛋白质 对补体系统九个中心成员的相互作用筛选确定C5 a为新型结合伴侣 PGRN对C5 a与C5 aR 1的结合有抑制作用。因此，科学的前提是， 这一竞争性继续申请的伊势是：1）14-3-3ε被鉴定为新组分 PGRN/TNFR 2途径的研究; 2）分离C5 a作为一种新的PGRN结合因子。核心假设 PGRN通过a）募集14-3-3ε， TNFR 2和PGRN/TNFR 2抗炎途径的活化;和B）与C5 a相互作用和抑制 C5 a/C5 aR 1炎症通路。具体目的是：（1）阐明14-3-3ε在PGRN/TNFR 2 - 1中的作用。 介导的巨噬细胞极化过程中的炎症性关节炎。我们将确定 对PGRN调节巨噬细胞极化的14-3-3ε的影响（SA#1.1）;信号传导、靶基因和共 在巨噬细胞极化中介导PGRN作用的14-3-3ε因子（SA#1.2）;以及 PGRN对炎症性关节炎巨噬细胞表型转换的调控及其依赖性 14-3-3ε（SA#1.3）。(2)为了明确PGRN/C5 a相互作用在炎症发病机制中的重要性， 关节炎我们将描述和剖析PGRN/C5 a相互作用，并确定PGRN衍生的最小 保留C5 a结合活性的片段/肽（SA#2.1）;阐明PGRN和C5 a之间的相互作用， 调节巨噬细胞极化，以及相关的信号传导途径（SA#2.2）;并确定 PGRN和C5 a/C5 aR 1信号传导之间的相互作用以及C5 a/C5 aR 1信号传导抑制的贡献 PGRN在炎性关节炎中的抗炎作用（SA#2.3）。拟议的研究将 不仅推进了我们对炎症性关节炎发病机制的理解，而且还可能导致 对各种TNFR和C5 a/C5 aR 1相关的病症和疾病采取新的干预措施。

Project Description TNFα/TNFR has received the greatest attention because of its position at the apex of the pro-inflammatory cy- tokine cascade, and its dominance in the pathogenesis of inflammation. TNFR1 primarily mediates inflammato- ry activity of TNFα, whereas TNFR2 plays a protective and anti-inflammatory role in various diseases. Our ge- netic screen for the binding partners of progranulin (PGRN) growth factor led to the isolation of TNFR2 as the PGRN-binding receptor (Tang, et al, Science, 2011). Remarkably, PGRN exhibits an approximately 600-fold higher binding affinity to TNFR2 than does TNFα. During the initial funding period, we have successfully identi- fied in a proteomics screen 14-3-3ε, an important intracellular signaling molecule, as a novel component of TNFR2 complexes in response to PGRN stimulation. PGRN deficiency promoted inflammatory classically- activated macrophage (CAM) but inhibited anti-inflammatory alternatively-activated macrophage (AAM) polari- zation, whereas recombinant PGRN inhibited AAM-CAM but stimulated CAM-AAM switching. In addition, knockout of 14-3-3ε abolished PGRN’s regulation of macrophage. More excitingly, our direct protein-protein interaction screen of nine central members of the complement system identified C5a as a novel binding partner of PGRN with high binding affinity, and PGRN inhibited the binding of C5a to C5aR1. Thus, the scientific prem- ise of this competitive continued application is based on 1) the identification of 14-3-3ε as a novel component of PGRN/TNFR2 pathway, and 2) the isolation of C5a as a novel PGRN-binding factor. The central hypothesis is that PGRN regulates macrophage polarization and inflammatory arthritis through a) recruitment of 14-3-3ε to TNFR2 and activation of the PGRN/TNFR2 anti-inflammatory pathway; and b) interplay with C5a and inhibition of C5a/C5aR1 inflammatory pathway. The Specific Aims are: (1) To elucidate 14-3-3ε’s role in PGRN/TNFR2- mediated macrophage polarization in the course of inflammatory arthritis. We will determine the dependence on 14-3-3ε of PGRN's regulation of macrophage polarization (SA#1.1); the signaling, target genes and co- factor(s) of 14-3-3ε that mediate PGRN action in macrophage polarization (SA#1.2); and the importance of PGRN regulation of macrophage phenotypic switch in the context of inflammatory arthritis and its dependence on 14-3-3ε (SA#1.3). (2) To define the importance of PGRN/C5a interplay in the pathogenesis of inflammatory arthritis. We will characterize and dissect the PGRN/C5a interaction and to identify PGRN-derived minimal fragment/peptide that retains C5a binding activity (SA#2.1); elucidate the interplay between PGRN and C5a in regulating macrophage polarization, as well as the signaling pathways involved (SA#2.2); and determine the interplay between PGRN and C5a/C5aR1 signaling and the contribution of inhibition of C5a/C5aR1 signaling by PGRN to PGRN's anti-inflammatory action in inflammatory arthritis (SA#2.3). The proposed research will not only advance our understanding of the pathogenesis of inflammatory arthritis, but may also lead to the de- velopment of new interventions for various TNFR- and C5a/C5aR1-related conditions and diseases.