Intestinal 5-HT Transporter: A novel therapeutic target for GI disorder

肠道 5-HT 转运蛋白：胃肠道疾病的新治疗靶点

• 批准号: 10361310
• 负责人: Ravinder K Gill
• 金额: $ 3.26万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10361310
• 关键词: AHR gene; Actinobacteria class; Affect; Agonist; Antiinflammatory Effect; Aryl Hydrocarbon Receptor; Attenuated; Bacteria; Bifidobacterium; Binding; Blood flow; CCL20 gene; CYP11A1 gene; CYP1A1 gene; Candidate Disease Gene; Cells; Chronic; Communities; Complex; Data; Diarrhea; Diet; Dietary Phytochemical; Disease; Down-Regulation; Drug Metabolic Detoxication; Effectiveness; Electrolytes; Enteral; Enterochromaffin Cells; Enzymes; Epithelial Cells; Event; Experimental Models; Functional disorder; Funding; Gastrointestinal tract structure; Gene Targeting; Genes; Genetic; Gut Mucosa; Health; Homeostasis; Hormones; Human; Ileitis; Immune; Immune response; Immunity; Impairment; Infection; Inflammation; Intervention; Intestinal Motility; Intestines; Knock-out; Knockout Mice; Lead; Ligands; Link; Maintenance; Mediating; Microarray Analysis; Modeling; Molecular; Mus; Neurons; Neurotransmitters; Nuclear Receptors; Oral Administration; Outcome; Pathogenesis; Pathologic; Pathway interactions; Patients; Physiological Processes; Predisposition; Probiotics; Receptor Activation; Receptor Signaling; Resistance; Role; Serotonin; Severities; Signal Pathway; Small Intestines; Structure; Supplementation; Susceptibility Gene; Therapeutic Intervention; Tissue-Specific Gene Expression; Transport Process; Tryptophan; Up-Regulation; Wild Type Mouse; Xenobiotic Metabolism; Xenobiotics; absorption; antimicrobial peptide; aryl hydrocarbon receptor ligand; bacterial community; cruciferous vegetable; dietary; dysbiosis; efficacy evaluation; extracellular; gut microbiota; ileum; in vivo Model; inflammatory disease of the intestine; insight; intestinal epithelium; microbiota; microbiota metabolites; mouse model; new therapeutic target; novel; novel therapeutic intervention; overexpression; prevent; response; reuptake; serotonin receptor; serotonin transporter; uptake; villin

PROJECT SUMMARY/ABSTRACT Serotonin transporter (SLC6A4; SERT) represents a primary mechanism to regulate 5-HT availability in the gut mucosa. A large body of evidence supports linkage of SERT to various GI disorders, however, the mechanisms are not well understood. Our recent studies and preliminary data demonstrated an entirely novel role of SERT and intracellular 5-HT in the activation of Aryl hydrocarbon receptor (AhR), a newly recognized IBD susceptibility gene. Interestingly, SERT KO mice fed with AhR agonist (β-naphthoflavone) showed impaired induction of CYP1A1, the canonical AhR gene target. Our preliminary data further showed that SERT was essential for the maintenance of healthy gut microbiota, as deletion of SERT in mice was associated with a reduction in actinobacteria and altered community structure that may affect the availability of ligands known to activate AhR. Since AhR pathways regulate gut immunity, the decrease in SERT may contribute to the pathophysiology of intestinal inflammation by suppressing basal and agonist-induced AhR activity. However, the mechanisms linking this novel paradigm of the role of serotonergic machinery in dysbiosis and agonist induced AhR activation are not known. Interestingly, dietary AhR ligands such as those present in cruciferous vegetables have protective roles in ameliorating intestinal inflammation. However, a decrease in SERT expression associated with inflammation may dampen their effects and reduce effectiveness in the course of IBD. We hypothesize that SERT-mediated uptake of 5-HT is crucial for the activation of AhR in response to dietary ligands. We also hypothesize that agents which activate SERT and/or counteract its down regulation will confer novel anti-inflammatory effects via AhR dependent mechanisms. Proposed studies in Specific Aim 1 will: a) investigate cell specific mechanisms by which 5-HT activates intestinal AhR utilizing mouse and human enteroids; b) examine whether loss of SERT renders resistance to the beneficial effects of dietary AhR ligands in TNBS ileitis model; and; c) elucidate the effects of microbiota in the activation of AhR pathways utilizing fecal transfer and investigate the link between SERT and the ability of microbiota to produce AhR ligands. Given that SERT is consistently shown to be decreased in all models of inflammation and patients with IBD, proposed studies in Specific Aim 2 will examine the efficacy of natural AhR ligands present in the diet in preventing the onset of gut inflammation, when combined with agents that upregulate SERT, such as probiotic Bifidobacteria breve. In addition, the role of SERT upregulation on mechanisms of AhR activation will be investigated utilizing state-of-the-art mouse model of epithelial cell- specific inducible overexpression of SERT. Outcome of the proposed studies should define the molecular mechanisms by which 5-HT activates AhR and should establish this novel link of the host serotonergic machinery with gut inflammation via AhR and gut microbiota/metabolites. These studies should also establish the beneficial role of SERT up regulation as a novel interventional strategy for IBD.

项目总结/摘要 5-羟色胺转运体（SLC 6A 4; SERT）是调节肠道5-HT利用率的主要机制 粘膜大量证据支持SERT与各种GI疾病的联系，然而， 机制还不太清楚。我们最近的研究和初步数据表明， SERT和细胞内5-HT在芳烃受体（AhR）激活中的作用， IBD易感基因有趣的是，用AhR激动剂（β-萘啶酮）喂养的SERT KO小鼠显示， CYP 1A 1（典型AhR基因靶点）诱导受损。我们的初步数据进一步表明，SERT 对于维持健康的肠道微生物群至关重要，因为小鼠中SERT的缺失与 放线菌的减少和群落结构的改变可能会影响已知配体的可用性， 激活AhR由于AhR途径调节肠道免疫，SERT的减少可能有助于肠道免疫。 通过抑制基础和激动剂诱导的AhR活性来研究肠道炎症的病理生理学。然而，在这方面， 将这种新的模式的β-肾上腺素能机制的作用，在生态失调和激动剂， 诱导的AhR活化是未知的。有趣的是，膳食AhR配体，如那些存在于十字花科植物中的配体， 蔬菜对改善肠道炎症有保护作用。然而，SERT的下降 与炎症相关的表达可能会抑制它们的作用，并降低治疗过程中的有效性。 IBD。我们假设SERT介导的5-HT摄取对AhR的激活至关重要， 对饮食配体的反应。我们还假设，激活SERT和/或抵消SERT的药物可能是一种免疫抑制剂。 其下调将通过AhR依赖性机制赋予新的抗炎作用。 具体目标1中提出的研究将：a）研究5-HT激活的细胞特异性机制 利用小鼠和人肠类的肠AhR; B）检查SERT的丧失是否使对 饮食AhR配体在TNBS回肠炎模型中的有益作用;以及c）阐明微生物群在TNBS回肠炎模型中的作用。 利用粪便转移激活AhR途径，并研究SERT与 微生物群产生AhR配体。考虑到SERT在所有模型中一致显示出降低， 炎症和IBD患者，具体目标2中提出的研究将检查天然AhR的疗效 当与 上调SERT，如益生菌短双歧杆菌。此外，SERT上调在 AhR激活的机制将利用最先进的上皮细胞小鼠模型进行研究， SERT的特异性可诱导过表达。拟议研究的结果应确定 5-HT激活AhR的机制，并应建立这种新的联系， 通过AhR和肠道微生物群/代谢物与肠道炎症机制。这些研究还应 确立SERT上调作为IBD的新型干预策略的有益作用。