Integrin-mediated matricellular signaling in experimental colitis

项目摘要 克罗恩病（CD）和溃疡性结肠炎（UC）是炎症性肠病（IBD）的两种主要亚型， 是病因不明确的慢性炎症性疾病。传统的治疗方法主要集中在 炎症的改善，尽管最近的研究表明粘膜愈合是一个重要的， 预后终点。此外，尽管进行了积极的抗炎治疗， CD患者因肠纤维化而发生狭窄，需要手术治疗。因此，存在未满足的需求， 替代治疗选择和治疗靶点。整合素结合基质细胞蛋白CCN 1 在CD和UC患者中，CYR 61表达上调，并成为关键的损伤反应。 在结肠炎中协调伤口愈合和组织修复的多个方面的分子。敲入小鼠 表达整合素结合缺陷型CCN 1的小鼠在实验中的发病率和死亡率增加， 结肠炎，表现为上皮再生受损、中性粒细胞持续存在和纤维化升高。小鼠 Lgr 5+肠道干细胞中的Ccn 1缺失显示实验性结肠炎后隐窝再生缺陷， 并且具有该基因型的小肠类器官表现出异常的Lgr 5+干细胞增殖。此外，委员会认为， 用纯化的CCN 1蛋白处理野生型或CCN 1突变小鼠显著促进粘膜上皮细胞增殖， 从结肠炎愈合，表明CCN 1对IBD的治疗潜力。基于这些发现，我们 假设CCN 1在肠干细胞和损伤后的隐窝再生中起关键作用， 可能会限制肠道纤维化。我们将在三个具体目标中仔细研究这一假设：（1）阐明 CCN 1在肠再生和干细胞增殖与分化中的作用;（2）评估CCN 1在肠再生和干细胞增殖与分化中的作用 CCN 1在结肠炎中性粒细胞清除和体内平衡中的作用;以及（3）检验以下假设： CCN 1可以通过诱导肌成纤维细胞衰老或凋亡来限制和逆转肠纤维化。这些 研究将产生关于CCN 1如何作用于结肠炎中肠损伤修复的多个方面的新见解， 并可能导致IBD的新的治疗策略和治疗靶点。

PROJECT SUMMARY Crohn’s disease (CD) and ulcerative colitis (UC), two major subtypes of inflammatory bowel disease (IBD), are chronic inflammatory disorders of poorly defined etiology. Traditional therapies have focused on amelioration of inflammation, although recent studies have indicated that mucosal healing is an important prognostic endpoint. Moreover, despite aggressive anti-inflammatory treatment, a significant percentage of CD patients develop strictures from intestinal fibrosis and require surgery. Thus, there is an unmet need for alternative treatment options and therapeutic targets. The integrin-binding matricellular protein CCN1 (CYR61) is upregulated in human patients with CD and UC, and is emerging as a key injury response molecule that coordinates multiple aspects of wound healing and tissue repair in colitis. Knockin mice expressing integrin-binding defective CCN1 suffer exacerbated morbidity and mortality in experimental colitis, showing impaired epithelial regeneration, neutrophil persistence, and elevated fibrosis. Mice with Ccn1 deletion in Lgr5+ intestinal stem cells show deficient crypt regeneration following experimental colitis, and mini-gut organoids with this genotype exhibit aberrant Lgr5+ stem cell proliferation. Furthermore, treatment of wild type or Ccn1 mutant mice with purified CCN1 protein significantly accelerates mucosal healing from colitis, suggesting a therapeutic potential of CCN1 for IBD. Based on these findings, we hypothesize that CCN1 plays critical roles in intestinal stem cells and crypt regeneration after injury, and may limit intestinal fibrosis. We will scrutinize this hypothesis in three specific aims: (1) to elucidate the functions of CCN1 in intestinal regeneration and stem cell proliferation and differentiation; (2) to evaluate the role of CCN1 in neutrophil clearance and homeostasis in colitis; and (3) to test the hypothesis that CCN1 can limit and reverse intestinal fibrosis by inducing myofibroblast senescence or apoptosis. These studies will yield new insights into how CCN1 acts on multiple aspects of intestinal injury repair in colitis, and may lead to new treatment strategies and therapeutic targets for IBD.