Bacterial amyloids break tolerance in lupus

 描述（由申请人提供）：系统性红斑狼疮（SLE）是一种多因素自身免疫性疾病，其中感染被认为是致病因素，最近的研究表明肠道植物群也起作用，但分子罪魁祸首仍有待发现。 细菌生物膜是多细胞细菌群落，在人类微生物组中丰富，并且在病原体慢性感染的建立中也很重要。目前还没有研究表明生物膜中存在的分子复合物是否有助于SLE的进展。我们最近发现细菌和真核生物的DNA被整合到卷曲纤维中，卷曲纤维是存在于沙门氏菌和大肠杆菌中的功能性细菌淀粉样蛋白。大肠杆菌生物膜。我们发现生物膜中的curli/DNA复合物激活传统的树突状细胞，导致促炎细胞因子的产生，包括I型干扰素，其在SLE中是致病的。体内注射curli/DNA复合物激活DC和B细胞，表明curli是一类新的复合危险信号。curli/DNA复合物的管理触发自身抗体的生产在狼疮易感NZBxW/F1小鼠，也在野生型小鼠，表明curli/DNA复合物的生物膜作为新的球员在SLE发病机制。为了将我们的发现应用于临床，我们开发了一种新的ELISA来测量抗curli抗体，并发现SLE患者在临床发作期间具有高水平的抗curli抗体。 我们建议通过研究curli直接激活B细胞的能力（可能通过TLR）来探索curli/DNA是否影响狼疮中的两个主要致病步骤：1）pDC对IFN Signature的刺激和2）自身反应性B细胞的激活，以作为诱导Ag特异性应答和破坏耐受性的佐剂来刺激狼疮自身抗体谱。初步结果表明，该菌感染大肠杆菌的能力较强. coli仅在细菌表达curli时诱导自身抗体，为研究curli作为狼疮发病机制中感染的主要分子刺激提供了强有力的理论基础。我们将测试curli是否是感染在加速狼疮发作和诱导发作中促自身免疫作用的主要介质。这些研究将使用鼠模型。 为了建立与人类疾病的强有力的致病联系，并得到我们初步结果的支持，我们还将研究人类样本，通过测量抗curli抗体的血清滴度，确定SLE患者是否比健康对照组暴露于curli，与疾病活动和爆发的发生相关。这些研究可能提供一种新的耀斑生物标志物，并建议靶向生物膜和细菌淀粉样蛋白作为狼疮的新治疗工具。

 DESCRIPTION (provided by applicant): Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease, in which infections are considered to play a pathogenic role, and more recent work is suggesting a role for the commensal flora as well, but the molecular culprits are still to be discovered. Bacterial biofilms are multicellular bacterial communities, abundant in the human microbiome, and also important in the establishment of chronic infection by pathogens. No study has yet addressed whether molecular complexes present in biofilms contribute to SLE progression. We have recently found that bacterial and also eukaryotic DNA is incorporated into curli fibers, functional bacterial amyloids present in Salmonella and E. coli biofilms. We found that curli/DNA complexes in biofilms activate conventional dendritic cells leading to production of pro-inflammatory cytokines, including Type I interferons, which are pathogenic in SLE. In vivo injection of curli/DNA complexes activated DCs and B cells, indicating that curli are a new class of composite danger signals. Administration of curli/DNA complexes triggered autoantibodies production in lupus-prone NZBxW/F1 mice and also in wild type mice, suggesting curli/DNA complexes from biofilms as novel players in SLE pathogenesis. To translate our finding to the bedside, we developed a new ELISA to measure anti-curli antibodies and found that SLE patients have high levels of anti-curli antibodies during clinical flares. We propose to explore if curli/DNA affect two major pathogenic steps in lupus: 1) the stimulation of IFN Signature by pDCs and 2) the activation of autoreactive B cells, by studying curli ability to directly activate B cells, possibly through TLRs, to act as an adjuvant to induce Ag-specific responses and break tolerance to stimulate a lupus autoAb profile. The Preliminary result that infection by a commensal E. coli induces autoAbs only when bacteria expressed curli, provides a strong rationale for studying curli as the dominant molecular stimulus by infections in lupus pathogenesis. We will test if curli is the main mediator of the pro-autoimmune effects of infections in accelerating lupus onset and inducing flares. These studies will use murine models. To establish a powerful pathogenic link with the human disease, and supported by our Preliminary results, we will also study human samples to determine whether SLE patients are exposed to curli more than healthy controls by measuring serum titers of anti-curli antibodies, in correlation with disease activity and occurrence of flare. These studies may provide a novel biomarker of flares and suggest targeting biofilms and bacterial amyloids as new therapeutic tools in lupus.