Regulators of immune complex mediated neutrophil antigen presentation

摘要 自身免疫性疾病是仅次于癌症和心脏病的第三大常见疾病 2350万美国人。这项赠款续期继续关注中性粒细胞Fcγ受体在自身免疫中的作用。 疾病。然而，它已经从理解中性粒细胞Fcγ受体在中性粒细胞中的作用和调节转向 肾小球肾炎(GN)患者血管内免疫球蛋白免疫复合体沉积后的募集检测 Fc-γ受体如何将中性粒细胞转化为高免疫原性抗原提呈细胞 对影响肾脏的自身免疫性疾病的贡献。这个新的方向是基于我们最近的研究。 结果表明，小鼠FcγRs或人FcγRIIA或Iib与具有免疫球蛋白复合体的成熟中性粒细胞结合 抗原(免疫复合体)导致它们分化为高活性的APC。这些细胞是 CDC在激活原始T细胞和将可溶性抗原交叉递呈给CD8T细胞方面可与CDC相媲美， 以前几乎完全分配给疾控中心的房产。FcγR与抗FcγRIIIB抗原的结合 结合物概述FcγR人源化小鼠免疫复合体的活性及其给药 在体内产生NAPCS，从而引发强大的获得性免疫。对狼疮患者样本的研究表明 血液中NAPC频率与临床疾病评分相关，提示NAPCS是致病的。 单细胞转录分析和验证研究表明，先锋转录因子PU.1在 中性粒细胞到NAPC的转化，并表明转录定义的中性粒细胞群体转化为 两个具有不同基因签名和功能的NAPC亚集。此外，我们提供的证据表明 FcγR内化和明确的表观遗传调控因子在转化过程中起着关键作用。在这里，我们建议1) 阐明NAPC亚群的功能及中性粒细胞对NAPC的表观遗传调控作用 转化，2)阐明与抗体-抗原复合体结合的FcγR的细胞内转运途径 并以CRISPR-CAS9为基础鉴定FcγR诱导免疫原性NAPC生成的机制 基因筛查，以及3)询问NAPCS在抗中性粒细胞胞浆抗体(ANCA)中的作用- 相关性肾小球肾炎和抗原耐受的NAPCS对疾病转归的影响。调控失调 是许多自身免疫性疾病的基础，目前的治疗方法对这些疾病是有效的。 仅在一小部分患者中使用，而且往往既不能治愈，也不能持久。具有APC标志的中性粒细胞 在从自身免疫性疾病到癌症的各种疾病中都有观察到。这项提案的结果可能会提供 对中性粒细胞向免疫原性转化的分子和细胞途径的重要见解 APC。这可以为许多免疫相关疾病的发病机制提供洞察力，并为 潜在非侵入性地产生大量携带APC的抗原池的新治疗方法的基础 旨在引起容忍或获得免疫力的。

ABSTRACT Autoimmune disease is the third most common disease category after cancer and heart disease that afflicts 23.5 million Americans. This grant renewal continues to focus on the role of neutrophil FcγRs in autoimmune diseases. However, it has shifted from understanding the role and regulation of neutrophil FcγRs in neutrophil recruitment following intravascular IgG-immune complex deposition in glomerulonephritis (GN) to examining how engaging FcγRs converts neutrophils into highly immunogenic antigen presenting cells (nAPC) and their contribution to autoimmune disorders effecting the kidney. This new direction is based on our recent studies showing that engaging mouse FcγRs or human FcγRIIA or IIIB on mature neutrophils with IgG-complexed antigen (immune complexes) leads to their differentiation into highly active APCs. These cells are comparable to cDCs in their ability to activate naïve T cells and cross-present soluble antigen to CD8 T cells, properties previously assigned almost exclusively to cDCs. Engaging FcγR with an anti-FcγRIIIB-antigen conjugate recapitulates the activity of immune complexes and its administration in FcγR humanized mice generates nAPCs in vivo that elicit robust acquired immunity. Studies in lupus patient samples indicate that nAPC frequency in blood correlates with clinical disease scores, which suggests that nAPCs are pathogenic. Single cell transcriptional analyses and validation studies implicate the pioneer transcription factor PU.1 in neutrophil to nAPC conversion and suggest that transcriptionally defined neutrophil populations convert to two nAPC subsets with distinct gene signatures and functionality. Furthermore, we provide evidence that FcγR internalization and a defined epigenetic regulator play a key role in conversion. Here we propose to 1) Elucidate the functionality of nAPC subsets and the role of epigenetic regulation in neutrophil to nAPC conversion, 2) Elucidate the route of intracellular trafficking of FcγR bound to antibody-antigen complexes and identify mechanisms of FcγR induced generation of immunogenic nAPCs using CRISPR-Cas9 based genetic screens, and 3) Interrogate the role of nAPCs in Antineutrophil cytoplasmic antibody (ANCA)- associated glomerulonephritis and the effect of antigen-tolerized nAPCs in disease outcomes. Dysregulation of the immune system is the basis of many autoimmune diseases for which current treatments are effective in only a subset of patients and are often neither curative nor durable. Neutrophils with APC markers have been observed in diseases from autoimmune diseases to cancer. Results from this proposal may provide important insights into the molecular and cellular pathways governing neutrophil conversion to immunogenic APCs. This could provide insights into the pathogenesis of many immune related disorders and lay the groundwork for new treatments that potentially non-invasively generate a large pool of antigen carrying APCs designed to elicit tolerance or acquired immunity.