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

有人认为慢性炎症会导致胃上皮细胞正常功能的异常。 细胞导致化生和异型增生的发展，并最终导致肿瘤的形成。两种肠道 化生(IM)和表达化生的痉挛多肽(SPEM)已被认为与 炎症诱发的胃肿瘤。骨形态发生蛋白(BMPs)调节生长和 胃肠道组织的分化。众所周知，BMP还可以抑制炎症、细胞增殖 和胃肿瘤的生长。Lgr5基因标志着胃上皮细胞能够自我更新和 表现出多谱系分化能力。在胃中检测到Lgr5ve细胞的数量增加。 肿瘤。此外，Lgr5ve细胞似乎是胃肿瘤的主要起源细胞。这些机制可以 目前对Lgr5ve细胞的调控及其在胃肿瘤发生发展中的作用尚不清楚。在研究中 在Lgr5-EGFP-Ires-CreerT2小鼠体内，我们观察到Lgr5细胞位于胃窦腺底部和沿 较小的曲度，这是一个经常引起胃肿瘤的区域。我们还报告说，抑制 转基因表达骨形态发生蛋白抑制物noggin(H/k-nog小鼠)在泌氧粘膜中的骨形态发生蛋白信号 增强幽门螺杆菌诱导的炎症，导致上皮细胞增殖增加，并导致 SPEM和异型增生的发展。在诺金和H同时在场的情况下进行的血统追踪研究。 Felis证实在Lgr5来源的细胞中有SPEM标记的表达。此外，删除BMPR1A和 费氏嗜血杆菌感染导致胃不典型增生和显著的细胞变化 粘膜，以CD44和Sox2分子在Lgr5ve细胞中表达增加为特征 与胃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信号的抑制/丢失诱导了Lgr5ve细胞的激活，这些细胞 分化为化生和发育不良的上皮细胞，并最终发展为肿瘤。在使用LGR5的第一个目标中- EGFP-Ires-CreERT2小鼠品系与noggin-番茄报告小鼠和Bmpr1aflox/Flox小鼠交叉，我们将 研究炎症过程中Lgr5细胞的去向。此外，我们将确定BMP信号是否调制 Sox2和CD44在Lgr5细胞中的表达及其是否介导了Lgr5的生物学反应 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Lgr5细胞的增殖和分化，BMP信号调节这一事件， 使用从小鼠胃和人胃活检中提取的胃有机化合物。在第三个目标中，为了 为了确定BMP信号在人类疾病中的意义，我们将测量BMP的表达， 炎性介质、干细胞标志物和BMP信号转导通路的组成部分 样本来自胃癌、胃炎和IM患者。在其他研究中，我们将评估 胃癌类有机物对细胞因子和骨形态发生蛋白的反应。

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.