Regulation of gastric metaplasia, dysplasia and neoplasia by Bone Morphogenetic Protein signaling

已经提出慢性炎症导致胃上皮正常功能的畸变 导致化生和发育异常的发展，并最终导致瘤形成的细胞。双肠 化生（IM）和痉挛性多肽表达化生（SPEM）与 炎症诱发的胃肿瘤。骨形态发生蛋白（BMPs）调节生长， 胃肠组织的分化。骨形成蛋白也被称为抑制炎症，细胞增殖， 和胃肿瘤的生长。Lgr 5基因标志着胃上皮细胞能够自我更新， 表现出多谱系分化能力。在胃粘膜中检测到Lgr 5 +ve细胞数量增加， 肿瘤的此外，Lgr 5 +ve细胞似乎是胃肿瘤的主要起源细胞。的机制 调节Lgr 5 +ve细胞及其在胃肿瘤形成中的作用目前尚不清楚。研究中 在Lgr 5-EGFP-ires-CreERT 2小鼠中进行，我们观察到Lgr 5 +ve细胞位于胃窦腺基部和沿着 胃小弯，这是一个经常引起胃肿瘤的区域。我们还报道了抑制 通过BMP抑制剂noggin的转基因表达在泌酸粘膜中的BMP信号传导（H+/k+-Nog小鼠） 增强螺杆菌诱导的炎症，导致上皮细胞增殖增加， SPEM和发育不良的发展。在noggin和H. 猫证明了SPEM标记物在Lgr 5衍生的细胞中的表达。此外，Bmpr 1a和 螺杆菌感染猫，引起发育不良的发展和显着的细胞变化的胃 粘膜，其特征在于Lgr 5 +ve细胞中CD 44和Sox 2分子的表达增加 与胃上皮化生和肿瘤的发生有关。在这项研究中，我们将测试 假设炎症和BMP信号传导的抑制/丧失诱导Lgr 5 +ve细胞的活化， 上升到化生和发育不良的上皮谱系，并最终形成瘤。在第一个目标中，使用Lgr 5- 将EGFP-ires-CreERT 2小鼠系与头蛋白-番茄报告基因小鼠和Bmpr 1aflox/flox小鼠杂交，我们将 研究炎症期间Lgr 5细胞的命运。此外，我们将确定BMP信号是否调节 Sox 2和CD 44在Lgr 5细胞中的表达，以及这些分子是否介导Lgr 5的生物学应答 细胞对炎症刺激的反应。在第二个目标中，我们将检验炎症分子 在体外调节Lgr 5细胞的增殖和分化，并且BMP信号传导调节该事件， 使用来源于小鼠胃和人胃活组织检查的胃类器官。第三个目标，为了 为了确定BMP信号传导在人类疾病中的意义，我们将测量BMP的表达， 炎症介质、干细胞标志物和BMP信号转导途径的组分在 来自胃癌、胃炎和IM患者的样品。在其他研究中，我们将评估 胃癌类器官对细胞因子和BMP的反应。

It has been proposed that chronic inflammation causes aberrations in the normal functions of gastric epithelial cells leading to the development of metaplasia and dysplasia and, ultimately, to neoplasia. Both Intestinal Metaplasia (IM) and spasmolytic polypeptide expressing metaplasia (SPEM) have been associated with inflammation-induced gastric neoplasms. The bone morphogenetic proteins, (BMPs) regulate the growth and differentiation of gastrointestinal tissues. The BMPs are also known to inhibit inflammation, cell proliferation and the growth of gastric neoplasms. The Lgr5 gene marks gastric epithelial cells that can self renew and exhibit multi-lineage differentiation capacity. An increased number of Lgr5+ve cells has been detected in gastric tumors. Moreover, Lgr5+ve cells appear to be a major cell-of origin of gastric neoplasms. The mechanisms that regulate Lgr5+ve cells and their role in the development of gastric neoplasia are currently unknown. In studies conducted in Lgr5-EGFP-ires-CreERT2 mice, we observed Lgr5+ve cells at the base of antral glands and along the lesser curvature, an area that frequently gives rise to gastric neoplasms. We also reported that inhibition of BMP signaling in the oxyntic mucosa by transgenic expression of the BMP inhibitor noggin (H+/k+-Nog mice) enhances Helicobacter-induced inflammation leading to increased epithelial cell proliferation and to the development of SPEM and dysplasia. Lineage tracing studies conducted in the presence of both noggin and H. felis demonstrated expression of markers of SPEM in Lgr5-derived cells. Moreover, deletion of Bmpr1a and infection with H. felis, caused the development of dysplasia and of significant cellular changes of the gastric mucosa, which were characterized by increased expression in Lgr5+ve cells of both CD44 and Sox2, molecules that have been linked to the development of gastric metaplasia and neoplasia. In this study we will test the hypothesis that inflammation and inhibition/loss of BMP signaling induce the activation of Lgr5+ve cells that give rise to metaplastic and dysplastic epithelial lineages, and ultimately, to neoplasia. In the first aim using Lgr5- EGFP-ires-CreERT2 mice lines crossed to both noggin-tomato reporter mice and to Bmpr1aflox/flox mice, we will investigate the fate of Lgr5 cells during inflammation. In addition, we will determine if BMP signaling modulates the expression of Sox2 and CD44 in Lgr5 cells and if these molecules mediate the biological response of Lgr5 cells to inflammatory stimuli. In the second aim, we will test the hypothesis that inflammatory molecules regulate the proliferation and differentiation of Lgr5 cells in vitro and that BMP signaling modulates this event, using gastric organoids derived from both mice stomachs and human gastric biopsies. In the third aim, in order to determine the significance of BMP signaling in human diseases, we will measure the expression of BMPs, inflammatory mediators, stem cell markers and of components of the BMP signal transduction pathway in samples derived from patients with gastric cancer, gastritis and IM. In additional studies, we will assess the response of gastric cancer organoids to cytokines and BMPs.