Identification of mechanisms for the tolerogenic predisposition of human thymic and tumor dendritic cells

鉴定人胸腺和肿瘤树突状细胞的耐受倾向机制

• 批准号: 420943261
• 负责人: Professorin Dr. Diana Dudziak
• 金额: --
• 依托单位: Institut für Immunologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/420943261?language=en
• 关键词: Identification; mechanisms; tolerogenic; predisposition; human

Dendritic cells (DCs) are key regulators of the immune system. To gain more knowledge on human primary DCs, we recently performed transcriptome and surfactome analyses . We could demonstrate that DC subsets isolated from the lymphohematopoietic system displayed a strong ontogenetic relationship. Interestingly, we further found that the microenvironment in non-lymphoid tissues exhibited a stronger influence on the overall DC transcriptome. As our previous results were obtained from the steady-state, we have now started to investigate the DC subpopulations under inflammatory conditions. Our preliminary data demonstrate that, although the DC subsets isolated from blood, thymic, and splenic tissues have a similar DC subset specific TLR expression profile, thymic DC subsets were diminished in their cytokine secretion upon stimulation. This was in contrast to blood and splenic DCs, which displayed the full activation spectrum, including the expression of costimulatory molecules and pro-inflammatory cyto-/chemokines, such as IL-12 and RANTES. This missing cyto- and chemokine secretion of thymic DCs was accompanied by a complete block of CD4+ T cell polarization into TH1 cells. As this behavior was observed after the isolation of the DCs and their stimulation in vitro, we here hypothesize that this effect might derive from a strong tolerogenic imprinting as consequence of the thymus environment. The observed semi-mature phenotype of thymic DCs might resemble the phenotype of tumor DCs. Therefore, we further hypothesize that the tumor microenvironment induces similar epigenetic and/or transcriptomic changes in infiltrating tumor DCs compared to DCs localized in the thymus. In order to test our hypotheses, we here want to i) determine functional differences between human blood and thymic DCs, ii) evaluate similarities and differences between human thymic and tumor DC subsets, and iii) analyze the mechanisms for tolerogenic predisposition of thymic and tumor DC subsets in experimental murine systems. Thus, to investigate transcriptional changes upon TLR ligand stimulation of sorted DC subpopulations isolated from thymi, blood, and tumors, we will perform RNAseq analyses, while the epigenetic status of these cells will be determined by ChIPseq analyses. Furthermore, we will functionally analyze candidate regulatory mechanisms, such as differences in intracellular signaling pathways and transcription factor activation. The measurement of DC and T cell responses will include multi-color flow cytometry, CBA, and PhosFlow assays. We expect that the identification of the key players involved in the tolerogenic predisposition of thymic and tumor DC subsets, allows for the development and testing of intervention strategies, e.g. to promote tumor therapies.

树突状细胞（DC）是免疫系统的关键调节剂。为了获得有关人类初级DC的更多知识，我们最近进行了转录组和表面分析。我们可以证明，从淋巴结腾系统中分离出来的DC子集表现出牢固的个体遗传关系。有趣的是，我们进一步发现，非淋巴组织中的微环境对整个DC转录组表现出更大的影响。由于我们先前的结果是从稳态获得的，因此我们现在开始研究在炎症条件下的DC亚群。我们的初步数据表明，尽管从血液，胸腺和脾组织中分离出的DC子集具有相似的DC子集特异性TLR表达谱，但胸腺DC亚群在刺激后的细胞因子分泌中减少了胸腺dc子集。这与表现出完整激活光谱的血液和脾脏DC相反，包括表达共刺激分子和促炎性细胞/趋化因子，例如IL-12和rantes。胸腺DC的这种缺失的细胞因子分泌伴随着CD4+ T细胞极化到Th1细胞中的完整块。由于在DC分离后观察到这种行为及其在体外刺激后，我们在这里假设这种影响可能源于胸腺环境的强烈耐受印迹。观察到的胸腺DC的半成熟表型可能类似于肿瘤DC的表型。因此，我们进一步假设，与胸腺中定位的DC相比，肿瘤微环境在浸润性肿瘤DCS中诱导了相似的表观遗传和/或转录组变化。为了检验我们的假设，我们在这里要i）确定人血和胸腺直流体之间的功能差异，ii）评估人胸腺和肿瘤DC亚群之间的相似性和差异，以及iii）分析了实验性鼠系统中胸膜和tumor tumor dc亚群的耐受性易感性的机制。因此，为了研究从百里香，血液和肿瘤分离出的TLR配体刺激的转录变化，我们将进行RNASEQ分析，而这些细胞的表观遗传状态将通过Chipseq分析确定。此外，我们将在功能上分析候选调节机制，例如细胞内信号通路和转录因子激活的差异。 DC和T细胞反应的测量将包括多色流式细胞仪，CBA和Phosflow分析。我们预计，鉴定胸腺和肿瘤DC亚群的耐受性倾向的主要参与者允许开发和测试干预策略，例如促进肿瘤疗法。