Role of TLR4 and the microbiome in colitis associated neoplasia

TLR4 和微生物组在结肠炎相关肿瘤中的作用

• 批准号: 10361471
• 负责人: Maria Teresa Abreu
• 金额: $ 34.54万
• 依托单位: UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2023-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10361471
• 关键词: Animal Model; Bacteria; Bioinformatics; Biological Process; Biopsy; Cell Death; Cell Proliferation; Cells; Characteristics; Chronic; Clinical; Colectomy; Colon; Colon Carcinoma; Colonic Neoplasms; Colonic inflammation; DNA Damage; Data; Defect; Diagnosis; Dimensions; Dysplasia; Enzymes; Epithelial; Epithelial Cells; Future; Gene Expression; Gene Expression Profile; Genes; Germ-Free; Gnotobiotic; Grant; Growth; Human; Hydrogen Peroxide; ITGAM gene; Immune; Immune signaling; Immune system; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Innate Immune Response; Intestines; Knockout Mice; Lamina Propria; Ligands; Link; Lipopolysaccharides; Malignant Neoplasms; Mediating; Methods; Molecular; Mucous Membrane; Mus; Mutation; Myelogenous; Myeloid-derived suppressor cells; NADP; NADPH Oxidase; Neoplasm Metastasis; Neoplasms; Oxidases; Oxidation-Reduction; Oxidative Stress; Patients; Phagocytes; Population; Positioning Attribute; Predisposition; Prevention; Process; Production; Proliferating; Proteobacteria; RNA; Reactive Oxygen Species; Resources; Risk; Role; S100A8 gene; Shapes; Signal Transduction; Signaling Molecule; Specimen; TLR4 gene; Testing; Therapeutic; Tissues; Transgenic Organisms; Transplantation; Tumor Stem Cells; Ulcerative Colitis; United States National Institutes of Health; Up-Regulation; Work; base; cancer stem cell; cancer survival; carcinogenicity; chemokine; colitis associated cancer; colitis-associated neoplasia; colon cancer risk; cytokine; dysbiosis; gut bacteria; immune activation; insight; intestinal epithelium; large bowel Crohn' s disease; metagenomic sequencing; microbial; microbial signature; microbiome; microbiota; mouse model; overexpression; prevent; recruit; response; stem cells; transcriptome sequencing; tumor; tumor microenvironment; tumor progression; tumorigenesis; tumorigenic

ABSTRACT We seek to understand the progression from inflammation to neoplasia in patients with inflammatory bowel disease (IBD). Often patients are diagnosed with dysplasia and undergo colectomies even though they will never develop cancer. The focus of our studies has been the link between intestinal bacteria and innate immune signaling leading to colitis-associated neoplasia. Toll-like receptor 4 (TLR4) recognizes LPS and other endogenous ligands present in the inflamed colon. Our group has shown that TLR4 is overexpressed in inflamed and dysplastic tissues of ulcerative colitis (UC) patients. Using transgenic and knock-out mice, we have shown that intestinal epithelial expression of TLR4 engenders a colitogenic microbiome capable of transmitting inflammation. Mice with constitutively active TLR4 in epithelial cells show dramatically increased epithelial proliferation and increased colonic tumors (AOM-DSS). Our preliminary data demonstrate that cancer stem cells from these tumors have a very distinct transcriptional profile compared to tumors in WT mice. We also show that TLR4-driven tumors have enhanced recruitment of tumor supporting myeloid-derived suppressor cells (MDSCs). TLR4-driven tumors have dramatic upregulation of NADPH oxidases and enhanced production of H2O2. H2O2 and other reactive oxygen species have several biological functions, including control of cell proliferation and microbial populations. In the current proposal, we hypothesize that dysregulation of TLR4 induces redox signaling, promoting stem cell activation and leading to selection of a tumorigenic microbiome. We further hypothesize that the dysbiotic microbiome activates MDSCs to promote CAC. This is pursued in the following specific aims: 1) Analyze the role of TLR4-mediated redox signaling on cancer stem cell activation in CAC. We will use our diverse animal models for TLR4 and the NADPH dual oxidase 2 (Duox2) to define how redox signaling participates in activation and survival of cancer stem cells during TLR4- driven tumorigenesis. 2) Interrogate the inter-relationship of TLR4-mediated redox signaling on mucosal dysbiosis and the consequences of dysbiosis in tumorigenesis. We will use our animal models and metagenomic sequencing to investigate how redox signaling through Duox2 participates in TLR4-mediated dysbiosis, and will use mucosa-associated microbial transplants to test the tumorigenic effects of this microbiota in germ-free mice. 3) Dissect the role of TLR4 in shaping the response of MDSCs to the resident microbiome during tumorigenesis. We will use dual RNA sequencing of bacterial and host RNA from tumor-associated MDSCs and MDSCs from UC patients to determine the interplay between the resident microbiota and tumor-promoting gene expression in MDSCs. We will also functionally characterize the pro- tumorigenic responses of MDSCs upon TLR4 stimulation including cytokine, chemokine, and H2O2 production. The work proposed herein will provide the mechanistic justification for subsequent human studies to target TLR4 or downstream signaling molecules as a means to halt progression from UC/inflammation to dysplasia and dysplasia to cancer.

抽象的 我们试图了解炎症性肠患者从炎症到肿瘤的进展 疾病（炎症性肠病）。通常，患者被诊断患有发育不良并接受结肠切除术，尽管他们将 永远不会患上癌症。我们研究的重点是肠道细菌与先天性之间的联系 免疫信号传导导致结肠炎相关肿瘤。 Toll 样受体 4 (TLR4) 识别 LPS 和其他 发炎结肠中存在内源性配体。我们的团队已经证明 TLR4 在 溃疡性结肠炎（UC）患者的发炎和发育不良组织。使用转基因和基因敲除小鼠，我们 已经表明，TLR4 的肠上皮表达产生了能够产生结肠炎的微生物群 传播炎症。上皮细胞中具有组成型活性 TLR4 的小鼠表现出显着增加 上皮增殖和结肠肿瘤增加（AOM-DSS）。我们的初步数据表明，癌症 与 WT 小鼠的肿瘤相比，这些肿瘤的干细胞具有非常独特的转录谱。我们 还表明 TLR4 驱动的肿瘤增强了肿瘤支持骨髓来源的募集 抑制细胞（MDSC）。 TLR4 驱动的肿瘤 NADPH 氧化酶显着上调并增强 H2O2 的产生。 H2O2 和其他活性氧具有多种生物学功能，包括控制 细胞增殖和微生物种群。在当前的提案中，我们假设失调 TLR4 诱导氧化还原信号传导，促进干细胞活化并导致选择致瘤细胞 微生物组。我们进一步假设失调的微生物组激活 MDSC 来促进 CAC。这是 追求以下具体目标：1）分析TLR4介导的氧化还原信号对癌症的作用 CAC 中的干细胞激活。我们将使用我们的多种动物模型来检测 TLR4 和 NADPH 双氧化酶 2 (Duox2) 定义氧化还原信号如何参与 TLR4-期间癌症干细胞的激活和存活 驱动肿瘤发生。 2) 探究粘膜上TLR4介导的氧化还原信号传导的相互关系 生态失调以及肿瘤发生中生态失调的后果。我们将使用我们的动物模型和 宏基因组测序研究 Duox2 的氧化还原信号如何参与 TLR4 介导 生态失调，并将使用粘膜相关微生物移植来测试其致瘤作用 无菌小鼠体内的微生物群。 3）剖析TLR4在塑造MDSC对细胞的反应中的作用 肿瘤发生过程中的常驻微生物组。我们将使用细菌和宿主 RNA 的双 RNA 测序 来自肿瘤相关的 MDSC 和来自 UC 患者的 MDSC，以确定驻留者之间的相互作用 MDSC 中的微生物群和促肿瘤基因表达。我们还将从功能上描述亲 MDSC 对 TLR4 刺激的致瘤反应，包括细胞因子、趋化因子和 H2O2 的产生。 本文提出的工作将为后续的人类研究提供机制依据 TLR4 或下游信号分子作为阻止 UC/炎症进展为不典型增生的手段 以及发育不良导致癌症。