SMAD4 regulation of colon epithelial cell inflammatory responses

SMAD4对结肠上皮细胞炎症反应的调节

• 批准号: 10192679
• 负责人: Robert Daniel Beauchamp
• 金额: $ 68.61万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10192679
• 关键词: ATAC-seq; Adult; Appendix Adenocarcinoma; BMP2 gene; Binding; Carcinogens; Carcinoma; Cell Differentiation process; Cell Line; Cells; ChIP-seq; Colitis; Colon; Colon Carcinoma; Colorectal Cancer; Complex; Cues; Cultured Cells; Cytokine Signaling; Distal; Endotoxins; Epigenetic Process; Epithelial; Epithelial Cells; Gatekeeping; Gene Deletion; Gene Expression; Genes; Genetic Transcription; Goals; Homeostasis; Human; Immune; Incidence; Inflammation; Inflammatory; Inflammatory Infiltrate; Inflammatory Response; Inflammatory Response Pathway; Injury; Intervention; Intestines; Knowledge; Large Intestine Carcinoma; Lead; Link; MADH4 gene; Malignant Neoplasms; Mediating; Metabolic; Mucous Membrane; Mus; Oncogenic; Organoids; Pathway interactions; Prevention; Production; Public Health; Regulation; Regulatory Pathway; Research; Role; Signal Pathway; Signal Transduction; Signaling Protein; Stimulus; TNF gene; Transcription Repressor; Transforming Growth Factor beta; Tumor Suppression; Tumor Suppressor Proteins; Ulcerative Colitis; Work; base; cancer invasiveness; carcinogenesis; chemokine; colitis associated cancer; colon carcinogenesis; cytokine; dextran sulfate sodium induced colitis; experimental study; genome-wide; improved; in vivo; insight; intestinal epithelium; microbiota; novel; novel therapeutic intervention; prevent; progenitor; recruit; response; stem; transcription factor; transcriptome sequencing; tumor; tumorigenesis

Project Summary While a number of studies have defined how inflammation arises and is maintained, much less is known about how it is resolved. We have found that colon epithelium is key to either exacerbating or suppressing inflammation. It is well-established that microbiota and immune cells signal to epithelial cells to increase production of chemokines and pro-inflammatory cytokines that can accelerate inflammation, but we have found that TGFb signaling via SMAD4 within the epithelium suppresses a pro-inflammatory transcriptional network. After conditional Smad4 gene deletion in the adult murine colonic epithelium, we found striking evidence for increased inflammatory signaling within the epithelial compartment concomitant with an increase in inflammatory infiltrate. Mechanistically, TGFb1 and/or BMP2 inhibit transcriptional induction of multiple inflammatory genes by TNF, IL- 1b, or LPS treatment in mouse and human cultured colon epithelial cells. Furthermore, >75% of mice with adult- onset deletion of the Smad4 gene in intestinal epithelium developed invasive mucinous adenocarcinomas of the distal colon within 3 months after dextran sodium sulfate (DSS)-induced colitis, while no tumors were found without colitis or in the SMAD4+ controls. In humans, we found a much higher incidence of SMAD4 loss in colitis- associated carcinoma (CAC) than in sporadic colorectal cancer. Based on our observations, we hypothesize that TGFb signaling via SMAD4 functions as a tumor suppressor, in part, through the inhibition of pro-inflammatory cytokine responses in intestinal epithelial cells. The major goal of this research is to determine the mechanisms by which TGFb superfamily signaling regulates colonic inflammatory responses and how this regulation is linked to tumor suppression. We will examine our hypothesis through the following specific aims: Aim 1. Determine the mechanism by which SMAD4-mediated signaling modulates cytokine signaling pathways in colon epithelial cells. Working hypothesis: SMAD4-mediated signaling inhibits transcriptional responses to inflammatory stimuli in colonic epithelial cells via specific inhibitory complexes on cytokine-induced genes. We will determine which genes are directly regulated by SMAD4 and how this regulation alters responses to pro-inflammatory cues in cultured cells and in vivo through a combination of RNA-seq, ATAC-seq and ChIP-seq experiments. Aim 2. Determine how dysregulated cytokine signaling regulates tumorigenesis in Smad4 null colonic epithelium. Working hypothesis: SMAD4-mediated suppression of epithelial inflammatory response genes is required to prevent tumorigenesis during colitis. We propose to examine in vivo how SMAD4 regulates specific inflammation- associated signaling pathways and gene expression and how those pathways contribute to suppression of CAC. We will identify these regulatory pathways using single cell analytical approaches to understand the cell-specific roles of SMAD4 within colon epithelium and will evaluate the role of SMAD4 in suppressing epithelial inflammatory genes in human CRC, particularly in CAC. Our work will yield better understanding of inflammatory regulation in colonic epithelium and is likely to identify novel regulatory targets for interventional strategies.

项目摘要 尽管许多研究定义了炎症的出现和维持方式，但对 如何解决。我们发现结肠上皮是加剧或抑制炎症的关键。 众所周知的是，微生物群和免疫细胞向上皮细胞发出信号，以增加 趋化因子和促炎细胞因子可以加速炎症，但我们发现TGFB 上皮内通过SMAD4发出信号会抑制促炎的转录网络。后 有条件的SMAD4基因缺失在成年鼠结肠上皮中，我们发现有惊人的证据表明增加 上皮室内的炎症信号传导伴随着炎症性浸润的增加。 从机械上讲，TGFB1和/或BMP2抑制TNF，IL-的多种炎症基因的转录诱导 小鼠和人培养的结肠上皮细胞中的1B或LPS处理。此外，成人> 75％的小鼠 肠上皮中Smad4基因的发作缺失发展了浸润性的浸润性粘液腺癌 硫酸钠（DSS）诱导的结肠炎后3个月内远端结肠，而未发现肿瘤 没有结肠炎或在SMAD4+对照中。在人类中，我们发现结肠炎中Smad4损失的发生率要高得多 相关癌（CAC）比零星结直肠癌。根据我们的观察，我们假设 TGFB通过SMAD4信号传导可作为肿瘤抑制剂，部分通过抑制促炎性 肠上皮细胞中的细胞因子反应。这项研究的主要目标是确定机制 TGFB超家族信号传导调节结肠炎症反应以及该调节如何联系 抑制肿瘤。我们将通过以下特定目的检查我们的假设：目标1。确定 SMAD4介导的信号传导调节结肠上皮细胞中的细胞因子信号通路的机制。 工作假设：SMAD4介导的信号传导抑制了对炎症刺激的转录反应 通过特异性抑制复合物在细胞因子诱导的基因上通过特异性抑制复合物。我们将确定哪个 基因由SMAD4直接调节，以及该调节如何改变对促炎线索的反应 培养的细胞和体内通过RNA-seq，atac-seq和chip-seq实验的结合。目标2。 确定细胞因子信号失调如何调节Smad4无效结肠上皮中的肿瘤发生。 工作假设：SMAD4介导的上皮炎症反应基因的抑制是需要 预防结肠炎期间的肿瘤发生。我们建议检查体内SMAD4如何调节特定炎症 - 相关的信号通路和基因表达以及这些途径如何促进CAC的抑制。 我们将使用单细胞分析方法来识别这些调节途径，以了解细胞特异性 Smad4在结肠上皮中的作用，并将评估Smad4在抑制上皮中的作用 人CRC中的炎症基因，特别是在CAC中。我们的工作将更好地理解炎症 结肠上皮的调节，可能会确定新的介入策略调节目标。