Anti-inflammatory actions of bone morphogenetic protein signaling in the stomach

描述（由申请人提供）：已知慢性炎症状态的存在会引起维持胃粘膜正常形态和功能特征的调节机制的扰动，导致胃炎、消化性溃疡和胃癌等疾病的发生。与这些疾病的发病机制有关的因素只得到部分描述。骨形态发生蛋白（bone morphogenetic protein， BMP）是一种对胃肠道组织生长和分化起重要作用的调节肽。此外，bmp已被证明在肠道中发挥抗炎作用，这表明它们可能代表了迄今为止尚未明确的胃肠道炎症调节因子。介导胃中bmp抗炎作用的机制目前尚不清楚。在一系列初步研究中，我们观察到诸如幽门螺杆菌（Hp）和INF-3等炎症刺激在体内和体外诱导BMP-4的表达，支持BMP-4参与胃炎症调节的观点。我们还注意到，在小鼠胃中转基因表达BMP抑制剂noggin，导致细胞因子（如MIP-2、INF-3和TNF-1）的表达增加，并增强激酶（如ERKs和JNKs）的激活，这些激酶参与促炎机制的调节。这些发现的相关性被观察到，与非转基因、年龄匹配的幼崽相比，转基因小鼠感染Hp会导致更大的炎症变化。最后，在一系列体外研究中，我们注意到BMP-2、BMP-4和BMP-7在培养的犬顶叶和粘液细胞中对基础和tnf -1刺激的IL-8基因表达都有直接的抑制作用。基于这些观察，我们假设BMP在胃中发挥抗炎作用，而BMP信号的缺乏导致更剧烈和强烈的炎症变化的发展。因此，本应用程序的总体目标是通过体内和体外两种方法，研究BMP信号在调节胃炎症机制中的功能和作用机制。在第一个具体目标中，我们将验证炎症刺激如Hp、IFN-3和TNF-1在体内调节BMP表达的假设，并且该事件可能代表一种下调炎症反应强度的自我安全机制。在第二个目标中，我们将通过对noggin转基因小鼠进行炎症刺激，阐明BMP信号在体内炎症反应调节中的作用。在第三个目标中，我们将关注BMP信号对分离的顶骨细胞和粘液细胞中IL-8表达的作用。通过提出的研究，我们希望能够提供对临床医学有重大意义的新见解，因为我们的发现可能有助于更好地理解消化性溃疡和胃癌等疾病的病理生理学。

DESCRIPTION (provided by applicant): The presence of chronic inflammatory states is known to cause perturbations in the regulatory mechanisms that maintain the normal morphological and functional features of the gastric mucosa, leading to the development of diseases such as gastritis, peptic ulcer and gastric cancer. The factors involved in the pathogenesis of these conditions have been only partially characterized. The bone morphogenetic proteins, (BMP) s are regulatory peptides that exert important actions on the growth and differentiation of gastrointestinal tissues. In addition, the BMPs have been shown to exert anti-inflammatory actions in the gut, suggesting that they might represent novel and hitherto poorly characterized regulators of gastrointestinal inflammation. The mechanisms mediating the anti-inflammatory actions of the BMPs in the stomach are currently unknown. In a series of preliminary studies we observed that inflammatory stimuli such as Helicobacter pylori (Hp) and INF-3 induce the expression of BMP-4 both in vivo and in vitro, supporting the notion that BMP-4 is involved in the regulation of gastric inflammation. We also noted that transgenic expression of the BMP inhibitor noggin in the mouse stomach, leads to increased expression of cytokines, such as MIP-2, INF-3 and TNF-1, and to enhanced activation of kinases, such as the ERKs and the JNKs, which are involved in the regulation of pro- inflammatory mechanisms. The relevance of these findings was underscored by the observation that infection of the transgenic mice with Hp, leads to the development of greater inflammatory changes than in non- transgenic, age matched, littermates. Finally, in a series of in vitro studies, we noted that BMP-2, BMP-4 and BMP-7 exert direct, inhibitory actions on both basal and TNF-1-stimulated IL-8 gene expression in cultures of canine parietal and mucus cells. On the basis of these observations we hypothesize that the BMPs exert anti- inflammatory actions in the stomach and that lack of BMP signaling leads to the development of more dramatic and intense inflammatory changes. Accordingly, the overall goal of this application is to investigate the function and the mechanisms of actions of BMP signaling in the regulation of inflammatory mechanisms in the stomach, by using both in vivo and in vitro approaches. In the first specific aim we will test the hypothesis that inflammatory stimuli such as Hp, IFN-3 and TNF-1 regulate BMP expression in vivo and that this event might represent a self-safe mechanism that down-regulates the intensity of the inflammatory response. In the second aim, we will elucidate the role of BMP signaling in the regulation of the inflammatory response in vivo, by challenging the noggin transgenic mice with the inflammatory stimuli. In the third aim, we will focus on the actions of BMP signaling on the expression of IL-8 in cultures of isolated parietal and mucus cells. Through the proposed studies, we expect to shed new insights that will have significant implications in clinical medicine since our discoveries may contribute to a better understanding of the pathophysiology of diseases such as peptic ulcer and gastric cancer.