Bacterial regulation of lipid immuno-modulators in patients with ulcerative colitis

总结 神经元流入肠腔在对感染因子的反应中是关键的，但 还与在特发性炎症性肠病（IBD）中观察到的肠损伤相关。我们 先前的研究表明，这种流入是由肝氧素A3的化学引诱作用介导的 （HXA 3）通过外排泵MRP 2从上皮细胞的腔表面分泌。初步研究 本文提供了上皮细胞从其顶端输出另一类生物活性脂质证据 表面，N-酰基乙醇胺类内源性大麻素通过多药耐药转运蛋白P- 糖蛋白（P-gp），可以抵消这种炎症反应。内源性大麻素信号传导的丧失 通过外周大麻素受体CB 2，导致病理学和中性粒细胞流入增加 急性肠道炎症期间，与IBD事件一致。这些初步数据强调， 上皮细胞在通过表面流出平衡促炎和抗炎脂质分泌中的关键作用 肠内分泌系统通过调节肠泵来控制中性粒细胞浸润并维持健康肠内的稳态。因此，在本发明中， 我们已经鉴定了肠中中性粒细胞功能的新的调节层。与其他反- 炎性脂质，例如由免疫细胞产生的专门的促消退介质， 我们已经发现上皮细胞组成性地产生和顶端分泌内源性大麻素， 我们称之为AMEND（活性调节上皮-中性粒细胞话语），以局部建立一个 抗炎环境，以维持肠道内稳态。因此，似乎有两个 系统，内源性大麻素途径的抗炎P-gp分泌和促炎P-gp分泌。 MRP 2分泌HxA 3途径，其以平衡和协调的方式发挥作用，可用于 由上皮细胞整合来自局部环境的信号，以维持对细胞的精确控制。 引发肠道炎症。我们试图进一步了解HXA 3和 中性粒细胞，并研究AMEND调节HXA 3活性的机制， 稳态和疾病。弥合这一差距可能有助于解释肠道细菌如何稳定 耐受性状态以及任一途径特定元件的遗传变异如何可能导致易感性 个人与IBD的发展有关。为了解决这些问题，我们将确定P-gp/AMEND是否 MRP 2/HXA 3通路调节微生物耐受和炎症反应之间的平衡。 这种平衡的紊乱导致病理性炎症。因此，目标1是 旨在评估Pgp/EC和MRP 2/HXA 3通路之间的失衡， 和目标2将检查是否微生态与健康的人类粪便差异 调节肠中的P-gp和MRP途径。

SUMMARY Neutrophil influx into the intestinal lumen is critical in the response to infectious agents, but is also associated with intestinal damage observed in idiopathic inflammatory bowel disease (IBD). Our prior studies have shown that this influx is mediated by the chemoattractant actions of hepoxilin A3 (HXA3) secreted from the luminal surface of epithelial cells by the efflux pump MRP2. Preliminary studies herein provide evidence that epithelial cells export another class of bioactive lipids from their apical surface, N-acyl ethanolamine class endocannabinoids via the multidrug resistance transporter P- glycoprotein (P-gp), which counteract this inflammatory response. Loss of endocannabinoid signaling through CB2, the peripheral cannabinoid receptor, leads to increased pathology and neutrophil influx during acute intestinal inflammation, consistent with events of IBD. Such preliminary data underscore a key role for epithelial cells in balancing the secretion of pro- and anti-inflammatory lipids via surface efflux pumps in order to control neutrophil infiltration and maintain homeostasis in the healthy intestine. Thus, we have identified a new layer of regulation of neutrophil function in the intestine. Unlike other anti- inflammatory lipids, such as the specialized pro-resolving mediators that are produced by immune cells, we have discovered that epithelial cells constitutively produce and apically secrete endocannabinoids, which we refer to as AMEND (activity modulating epithelial-neutrophil discourse), to locally establish an anti-inflammatory environment to maintain intestinal homeostasis. Thus, it appears that there are two systems, an anti-inflammatory P-gp secretion of endocannabinoids pathway and a pro-inflammatory MRP2 secretion of HxA3 pathway, that function in a balanced and coordinated manner that can be used by epithelial cells to integrate signals from the local environment to maintain exquisite control over the initiation of intestinal inflammation. We seek to further understand the interaction between HXA3 and neutrophils, and to investigate the mechanisms by which AMEND regulates HXA3 activity during homeostasis and disease. Bridging this gap could help explain how commensal bacteria can stabilize a state of tolerance and how genetic variations in specific elements of either pathway might predispose individuals to development of IBD. To address these questions, we will determine whether P-gp/AMEND and MRP2/HXA3 pathways modulate the balance between microbial tolerance and inflammatory responses, and that disturbance of this balance leads to pathological inflammation. Thus, Aim 1 is designed to assess the imbalance between the Pgp/EC and MRP2/HXA3 pathways in patients who suffer from ulcerative colitis, and Aim 2 will examine whether dysbiotic vs. healthy human stool differentially modulates the P-gp and MRP pathways in the intestine.