The inflammatory consequence of arsenic-mediated urothelial endocrine disruption

砷介导的尿路上皮内分泌干扰的炎症后果

• 批准号: 9266205
• 负责人: Tiffani J Houston
• 金额: $ 4.06万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2018-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9266205
• 关键词: Address; Affect; Angiopoietins; Anti-Inflammatory Agents; Anti-inflammatory; Arsenic; Arsenicals; Awareness; Binding; Binding Sites; Biological Assay; Bladder; Cellular Stress; Chronic; Chronic Disease; Cytokeratin; DNA Binding Domain; DNA-Binding Proteins; Data; Development; Diabetes Mellitus; Disease; Dose; Endocrine Disruptors; Endocrine System Diseases; Endocrine disruption; Ensure; Environment; Environmental Medicine; Epithelial; Epithelium; Equilibrium; Gene Expression; Gene Targeting; Genetic Transcription; Glucocorticoid Receptor; Health; Human; Inflammation; Inflammation Mediators; Inflammatory; Inflammatory Response; Injury; Kidney; Kinetics; Lead; Link; Liver; Lung; Malignant Neoplasms; Mediating; Metaplasia; Metaplastic; Mutation; Organ; Pathologic; Physiological; Play; Population; Preventive measure; Process; Proteins; Reporter; Research Training; Role; Scientist; Signal Transduction; Skin; Source; Specificity; Testing; Time; Toxic effect; Toxin; Transactivation; Transcriptional Regulation; Translating; Urothelial Cell; Urothelium; Water; Wound Healing; base; career; cell injury; cell motility; disorder prevention; drinking water; glucocorticoid receptor alpha; improved; inflammatory milieu; innovation; knock-down; novel; public health relevance; receptor function; response; response to injury; steroid hormone receptor; transcription factor; wound closure

 DESCRIPTION (provided by applicant): Inorganic arsenic (iAs) is the highest-ranking toxin on the U.S. substance priority list. Chronic exposure through natural water sources is linked to a broad range of adverse health effects, including pathological changes in the urinary bladder. Due to the make up of the urothelial cell, iAs readily accumulates to elicit toxic effects. However the specific mechanisms of arsenic-induced urothelial injury are not fully characterized. Upon cell injury there is rapid influx of inflammatory mediators and increase in cellular inflammatory signaling. The glucocorticoid receptor (GR) is an anti-inflammatory transcription factor, critical o maintain the balance between pro- and anti-inflammatory processes. iAs is classified as an environmental endocrine disruptor and is known to inhibit GR transcription factor function of target genes. Angiopoietin-like protein 4 (ANGPTL4) is a target gene of GR that plays a role in wound healing in response to epithelial injury. Notably, ANGPTL4 expression is decreased following iAs exposure in human urothelial cells (HUC). Moreover, treatment of HUC with inflammatory agents increases ANGPTL4 expression, and knockdown of ANGPTL4 decreases wound closure capabilities. However, it is unknown how arsenic disrupts the GR/ANGPTL4 axis in response to urothelial injury. Thus, the hypothesis of this proposal contends that iAs decreases GR-mediated expression of ANGPTL4 and disrupts normal urothelial response to injury by decreasing wound closure and sustaining the inflammatory response. The hypothesis will be addressed by completing the following two specific aims. First, the kinetics, specificity, and mechanism of arsenic inhibition on GR transcription factor function will be explored using reporter assays, DNA-protein binding assays, and mutations at suspected iAs binding sites within the GR DNA binding domain. Second, HUC with varying combinations of GR mutations and ANGPTL4 knockdown will be subjected to functional assays to assess changes in cell motility and inflammatory response. The changes in wound healing and inflammation will be observed with and without iAs treatment. Results from these aims will provide a mechanism of arsenical endocrine disruption in the bladder and validate ANGPTL4 as a novel GR target in response to injury and inflammation. Further, aberrant physiological responses and mechanisms after urothelial injury as a result of iAs exposure will be determined. The significance of this study applies to a broad range of arsenic-induced disease in the skin, lung, liver, and kidney. There may also be improved characterization of additional endocrine disease linked to chronic iAs, such as diabetes. Because inflammation is an underlying mechanism in many chronic diseases, this proposal has the potential to translate into preventative measures and bring more awareness to the role of the environment on human health, a concept that is not yet fully appreciated. Overall, completion of this study will ensure my comprehensive research training and contribute to the development of a successful career as an independent clinician-scientist of environmental medicine and disease prevention.

 描述（由申请人提供）：无机砷（iAs）是美国物质优先列表中排名最高的毒素。通过天然水源长期接触会对健康产生广泛的不利影响，包括膀胱的病理变化。由于尿路上皮细胞的组成，iAs很容易积累，引起毒性作用。然而，砷诱导的尿路上皮损伤的具体机制尚未完全确定。在细胞损伤时，存在炎性介质的快速流入和细胞炎性信号传导的增加。糖皮质激素受体（GR）是一种抗炎转录因子，对维持促炎和抗炎过程之间的平衡至关重要。iAs被归类为环境内分泌干扰物，已知可抑制靶基因的GR转录因子功能。血管生成素样蛋白4（ANGPTL 4）是GR的靶基因，其在响应上皮损伤的伤口愈合中起作用。值得注意的是，在人尿路上皮细胞（HUC）中iAs暴露后ANGPTL 4表达降低。此外，用炎性试剂治疗HUC增加ANGPTL 4表达，并且ANGPTL 4的敲低降低伤口闭合能力。然而，目前尚不清楚砷如何破坏GR/ANGPTL 4轴响应尿路上皮损伤。因此，该提议的假设认为iAs降低GR介导的ANGPTL 4表达，并通过降低伤口闭合和维持炎症反应来破坏正常的尿路上皮对损伤的反应。该假设将通过完成以下两个具体目标来解决。首先，砷抑制GR转录因子功能的动力学，特异性和机制将使用报告分析，DNA-蛋白质结合分析，并在可疑的iAs结合位点内的GR DNA结合域的突变进行探讨。其次，具有GR突变和ANGPTL 4敲低的不同组合的HUC将经受功能测定以评估细胞运动性和炎症反应的变化。将观察有和无iAs治疗的伤口愈合和炎症变化。这些目标的结果将提供膀胱中砷内分泌干扰的机制，并验证ANGPTL 4作为响应损伤和炎症的新型GR靶点。此外，将确定iAs暴露导致的尿路上皮损伤后的异常生理反应和机制。这项研究的意义适用于广泛的砷引起的皮肤，肺，肝，肾疾病。还可能改善与慢性iA相关的其他内分泌疾病（如糖尿病）的表征。由于炎症是许多慢性疾病的潜在机制，因此这一建议有可能转化为预防措施，并使人们更多地认识到环境对人类健康的作用，这一概念尚未得到充分认识。总的来说，完成这项研究将确保我全面的研究培训，并有助于发展一个成功的职业生涯作为一个独立的临床医生，科学家的环境医学和疾病预防。