The Role of Crypt Fissioning in IBD Ulcer Healing

项目总监/首席调查员(巴雷特，特伦斯，A)： 黏膜愈合在炎症性肠病(IBD)中的重要性源于临床数据 证明它是病情缓解的预测因子1。因此，溃疡愈合预测了治疗预防的能力。 不想要的临床后遗症(即手术)。不幸的是，许多IBD患者仍然难以治愈或失去治疗。 对导致持续性粘膜溃疡的治疗的反应性。未来的儿科研究表明 线粒体基因表达减少预示溃疡性结肠炎(UC)2的不良结局。 得到Kugathasan等人的支持，他们发现线粒体呼吸链的表达增加 基因预测有利(B1保护)克罗恩病(CD)的结果3。基于这些结果和我们的 自己的数据，我们假设IBD慢性溃疡的一个关键驱动因素是肠道衰竭 随着ROS的产生，上皮细胞(IEC)增加线粒体的呼吸。我们假设这是慢性的 粘膜炎症抑制小鼠隐窝分裂(溃疡愈合)所需的线粒体呼吸 IBD。这一假设将在以下研究中得到验证：目标1.确定 线粒体呼吸促进粘膜愈合。这些研究得益于令人惊叹的新奇普莱姆。 使用VilCre/mTmG/TFAMfl/fl小鼠的数据，其中线粒体呼吸被证明需要 溃疡愈合中的隐窝分裂。在目标2中，我们将确定线粒体的需求- 在IEC隐窝区使用原代人类结肠镜获得ROS。AIM 3研究将确定 慢性炎症对患者溃疡愈合的影响。溃疡的IEC转录本 CD和溃疡性结肠炎的边缘将与正常的溃疡愈合进行比较。正常溃疡愈合 将使用一种新的活检(Bx/Bx)方法进行询问(IEC将从 Bx/Bx部位在首次活检后4-6天)。ScRNAseq结果已经表明线粒体 生物发生(Pgc1)在Bx/Bx溃疡中增加，而在IBD IEC中下降。总结：研究 将通过询问新的小鼠、人来调查IBD溃疡无法愈合的原因 确定线粒体呼吸抑制影响的体外结肠样体培养模型 关于IEC的反应(隐窝分裂)。这些研究将检验慢性粘膜 炎症(如在IBD中)抑制线粒体呼吸，从而阻碍ROS诱导 PI3K信号和隐窝分裂。我们的目标是确定治疗靶点，以增强 线粒体呼吸在IBD黏膜修复中的作用。 OMB编号0925-0001/0002(01/18修订版批准至2020年3月31日)页面续格式页面

Program Director/Principal Investigator (Barrett, Terrence, A): The importance of mucosal healing in inflammatory bowel disease (IBD) derives from clinical data that demonstrate it to be a predictor of remission1. Thus, ulcer healing predicts the capacity for therapies to prevent unwanted clinical sequelae (i.e. surgery). Unfortunately, many IBD patients remain refractory or lose responsiveness to therapies leading to persistent mucosal ulceration. Prospective pediatric studies show that reduced mitochondrial gene expression predict unfavorable outcomes in ulcerative colitis (UC)2. These findings were supported by Kugathasan et al who found that increased expression of mitochondrial respiratory chain genes predicted favorable (B1 protected) Crohn’s disease (CD) outcomes3. Based on these results and our own data, we hypothesize that a critical driver of chronic ulceration in IBD is the failure of intestinal epithelial cells (IEC) to increase mitochondrial respiration with ROS generation. We posit that chronic mucosal inflammation suppresses mitochondrial respiration needed for crypt fissioning (in ulcer healing) in IBD. This hypothesis will be tested in the following studies: Aim 1. Determine the impact of mitochondrial respiration for mucosal healing. These studies benefit from strikingly novel Prelim. Data using VilCre/mTmG/TFAMfl/fl mice where mitochondrial respiration was shown to be required for crypt fissioning in ulcer healing. In Aim 2 we will determine the requirement of mitochondrial- derived ROS in IEC crypt division using primary human colonoids. Aim 3 studies will determine the impact of chronic inflammation on ulcer healing in patients. IEC transcriptomics from ulcer edges from CD and ulcerative colitis will be compared to normal ulcer healing. Normal ulcer healing will be interrogated using a novel biopsy of a biopsy (Bx/Bx) approach (IEC will be isolated from Bx/Bx sites 4-6day after initial biopsies). ScRNAseq results have already shown that mitochondrial biogenesis (PGC1) increases in Bx/Bx ulcers whereas levels drop in IBD IEC. In summary: Studies will investigate the cause of non-healing ulceration in IBD by interrogating novel murine, human and in vitro colonoid culture models of determining the impact of suppressed mitochondrial respiration on IEC responses (crypt fissioning). The studies will test the notion that chronic mucosal inflammation (as in IBD) suppresses mitochondrial respiration which impedes ROS-induced PI3K signaling and crypt fissioning. Our goal is to identify therapeutic targets to allow for enhanced mitochondrial respiration to aide mucosal repair in IBD. OMB No. 0925-0001/0002 (Rev. 01/18 Approved Through 03/31/2020) Page Continuation Format Page