Enteric glial ETBR signaling in postoperative ileus

尽管实施了胃肠道手术的增强恢复方案，但仍有显著的 延长的术后肠梗阻(POI)和术后胃肠功能障碍(POGD) 住院人数、发病率增加和医疗费用高达数十亿美元。正在筹备中的新疗法是 有限的。需要对POI的发病机制(S)有更好的了解，以制定更好的治疗方法 战略。越来越多的证据表明，肠神经胶质细胞在人的健康和疾病中起着重要作用。 胃肠道。内皮素(ET-1)在肠道“反应性肠胶质细胞”中的信号转导是一个新的靶点 POI和POGD发病机制的研究(Gulbrensan&Christofi，Gastro，2018)。我们最近 工作、强大的先导性、可行性和初步数据(图1-16)、摘要和出版物支持这部小说 假设肠神经胶质细胞中的胶质ET-1/ETBR信号扰乱了运动性，它有助于 肠道炎症背景下的POI和POGD的发病机制。致病机理(S) 涉及内皮素的包括胶质细胞对ET-1/ETBR信号的超敏反应，反应性胶质细胞的诱导 表型、肠胶质细胞增多症、肠神经病变和神经运动通路的改变。我们的研究 还将研究靶向ETBR在POI和POGD中的治疗潜力。我们将测试我们的 小鼠和人的3个特定目标的一般假设：目标1将重点放在ET-1/ETBR的机制上 运动性的抑制。使用多层次方法研究ETBR对小鼠和人运动的影响，包括 肌肉收缩、蠕动波、小球推进、上行和下行反射以及胃肠道运动。 ETBR信号在胶质细胞、神经元和运动性中的研究是在细胞特异性的钙离子报告小鼠的胶质细胞、神经元、 兴奋性和抑制性神经元通路、胶质细胞条件性ETBR消融或ET-1上调的转基因模型 调节，和ETBR-EGFP报告小鼠。研究结果从小鼠到人类的可译性测试 人类EGC网络中的Ca~(2+)波是人类首次在肌间神经节网络中记录到的膜片钳记录， 以及对上升和下降反射的ETBR研究。目标2将集中在致病机制上。 肠神经胶质细胞ETBR信号转导机制包括ET-1/ETBR的超敏反应 信号，RNAseq分析的RiboTag小鼠反应性胶质表型的诱导，以及由 与胶质细胞特异的ETBR基因敲除的RiboTag杂交。研究结果对人类的可译性在hegc中进行了测试。 或带有钙离子或膜片钳记录的神经节网络。在小鼠身上测试对肠道神经病变的影响 神经胶质细胞消融ETBR或ET-1上调钙离子报告小鼠神经元。目标3将专注于胶质细胞ET-1 和ETBR作为POI的治疗靶点，使用POI和结肠切除术的肠道外科操作模型 POI患者和小鼠的药物拮抗剂，或对ETBR或UP进行胶质细胞消融的小鼠的测试 ET-1的调节。总之，术后肠梗阻的一种新的胶质细胞ET-1/ETBR致病机制可能是 被确定为预防性治疗的相关治疗目标。

Despite the implementation of enhanced recovery protocols for GI surgeries, there is still significant postoperative ileus (POI) and postoperative gastrointestinal dysfunction (POGD) associated with prolonged hospitalizations, increased morbidity and health care costs into the billions. Novel therapies in the pipeline are limited. A better understanding of the pathogenic mechanism(s) of POI is required to develop better therapeutic strategies. Emerging evidence indicates that enteric glia play an important role in health and disease of the gastrointestinal tract. Endothelin (ET-1) signaling'` in `reactive enteric glia' in the gut is a novel target of investigation for us in the pathogenesis of POI and POGD (Gulbrensan & Christofi, Gastro, 2018). Our recent work, strong pilot, feasibility and preliminary data (Figs 1-16), abstracts and publications support the novel hypothesis that glial ET-1 / ETBR signaling in enteric glia disrupts motility and it contributes to the pathogenesis of POI and POGD in the context of intestinal inflammation. Pathogenic mechanism(s) involving endothelins include glial hypersensitivity to ET-1/ETBR signaling, induction of a reactive glial phenotype, enteric gliosis, enteric neuropathy, and alterations in neural-motor pathways. Our study will also investigate the therapeutic potential of targeting ETBR in POI and POGD. We will test our general hypothesis in 3 specific aims in mice and humans: Aim 1 will focus on the Mechanism of ET-1/ETBR inhibition of motility. A multi-tier approach is used to study ETBR on motility in mouse and human, including muscle contraction, peristaltic waves, pellet propulsion, ascending and descending reflexes and GI transit. ETBR signaling in glia, neurons and motility is studied in cell-specific Ca2+ reporter mice for glia, neurons, excitatory and inhibitory neuron pathways, transgenic models of glial conditional ETBR ablation or ET-1 up regulation, and ETBR-EGFP reporter mice. Translatability of findings from mice to humans is tested on Ca2+waves in human EGC networks, `first in human' patch clamp recordings in networks of myenteric ganglia', and ETBR studies of ascending and descending reflexes. Aim 2 will focus on the pathogenic mechanism of ETBR signaling in enteric glia in POI – Pathogenic mechanisms include hypersensitivity in ET-1/ETBR signaling, induction of a reactive glial phenotype analyzed by RNAseq in RiboTag mice, and mice generated by crossing RiboTag with glial-specific ETBR knockouts. Translatability of findings to humans is tested in hEGCs or networks of ganglia with Ca2+or patch clamp recordings. Impact on enteric neuropathy is tested in mice with glial ablation of ETBR or ET-1 up regulation in Ca2+reporter mice for neurons. Aim 3 will focus on glial ET-1 and ETBR as a therapeutic target in POI using a gut surgical manipulation model of POI and colectomy patients with POI, and pharmacological antagonists in mice, or testing in mice with glial ablation of ETBR or up regulation of ET-1. Overall, a novel glial ET-1 / ETBR pathogenic mechanism of postoperative ileus may be identified as a relevant therapeutic target for prophylactic treatment.