Regulation of Intestinal Stem Cell Activation in Colitis

描述（由申请方提供）：炎症性肠病（IBD）中诱导粘膜愈合与减少住院和手术相关。粘膜屏障的愈合需要控制破坏性炎症反应以及通过增强增殖和产生新的隐窝结构来恢复上皮屏障。 虽然Wnt/B-连环蛋白激活的诱导是肠干细胞（ISC）和祖细胞（PC）激活的关键因素，但很少有研究人员研究结肠炎中B-连环蛋白激活的调节，其中粘膜愈合和炎症诱导的发育不良是主要的临床问题。在之前的奖励期间进行的研究表明，在结肠炎和结肠炎诱导的癌症期间，B-连环蛋白的Akt磷酸化在ISC中增加。本提案利用一种新的遗传模型来减少结肠炎期间结肠肠上皮细胞（IEC）中的PI 3 K信号传导。在给予DSS结肠炎的VilCre/pik 3r 1fl/fl小鼠中已经产生的数据表明，PI 3 K介导的B-连环蛋白活化在伤口愈合中起主要作用。将在VilCre/pik 3r 1fl/fl小鼠中产生DSS结肠炎的急性和慢性形式， AIM 1中的体内研究，以检查IEC 1A类PI 3 K在粘膜愈合、B-连环蛋白活化和ISC/PC基因表达中的作用（使用新型肠样培养物）。AIM 2研究利用骨髓嵌合体（BMC）小鼠检查DSS结肠炎小鼠放射抗性上皮细胞群中TNF诱导的IEC B-连环蛋白信号传导。AIM 3研究使用B6-> Nox 1-/- BMC DSS结肠炎小鼠检测Nox 1在B-连环蛋白激活中的作用。总之，这些研究表明，TNF诱导的NOX 1刺激PI 3 K介导的B-连环蛋白激活和ISC/PC基因表达，以确定IBD中的隐窝反应。潜在的假设是炎症诱导的B-连环蛋白信号传导通过增加结肠炎期间的ISC和祖细胞扩增来增强上皮再生并诱导慢性结构扭曲。这些研究的临床相关性很大，因为我们希望确定IBD治疗和化学预防的新方法。

DESCRIPTION (provided by applicant): Induction of mucosal healing in inflammatory bowel disease (IBD) is associated with reduced hospitalizations and surgeries. Healing of the mucosal barrier requires control of the destructive inflammatory response as well as restitution of the epithelial barrier through enhanced proliferation and generation of new crypt structures. Although it is clear that induction of Wnt/B-catenin activation is a key factor in intestinal stem ell (ISC) and progenitor cell (PC) activation, there are few researchers that examine the regulation of B-catenin activation in colitis where mucosal healing and inflammation-induced dysplasia are major clinical concerns. Studies performed during the prior award period demonstrated that Akt phosphorylation of B-catenin increases in ISCs during colitis and colitis-induced cancer. The present proposal makes use of a novel genetic model for reducing PI3K signaling in colonic intestinal epithelial cells (IEC) during colitis. Data already produced in VilCre/pik3r1fl/fl mice given DSS colitis suggest that PI3K-mediated B-catenin activation plays a major role in wound healing. Acute and chronic forms of DSS colitis will be generated in VilCre/pik3r1fl/fl mice for in vivo studies in AIM 1 to examine the role of IEC class 1A PI3K in mucosal healing, B-catenin activation and ISC/PC gene expression (using novel enteroid cultures). Studies in AIM 2 utilize bone marrow chimera (BMC) mice to examine TNF-induced IEC B-catenin signaling in radioresistant epithelial populations in DSS colitis mice. AIM 3 studies examine the role of Nox1 in B-catenin activation using B6->Nox1-/- BMC DSS colitis mice. Together the studies propose that TNF-induced NOX1 stimulates PI3K-mediated B-catenin activation and ISC/PC gene expression to determine crypt responses in IBD. The underlying hypothesis is that inflammation-induced B-catenin signaling enhances epithelial regeneration and induces chronic architectural distortion by increasing ISC and progenitor cell expansion during colitis. The clinical relevance of these studies is great given that we hope to identify novel approaches to IBD therapy and chemoprevention.