Role of Muc5b in Honeycomb Cyst Formation

项目总结 这项建议的总体科学目标是建立在我们在MUC5B相关特发性疾病上的发现的基础上 了解肺纤维化(IPF)的基本机制。IPF是一个毁灭性的 每年在全球范围内夺走500万人生命的疾病。它的特点是进行性肺纤维化和 形成微小的蜂窝(HC)囊。尽管最近出现了一些治疗方法， IPF的治疗受到我们对其病理生物学的了解的限制。我们发现一种函数增益 MUC5B基因上游3kb多态是IPF发生的最大危险因素。在……里面 在小鼠的初步实验中，我们证明了MUC5B的过表达导致了 博莱霉素和流感引起的纤维化。然而，在没有肺损伤的情况下过度表达MUC5B并不是 足以引发纤维化。IPF中的基因表达分析表明MUC5B与 用HC表达。同样，我们和其他人也发现，HCS含有重要的MUC5B蛋白。一个 最近的出版物指出，小鼠在流感损伤的背景下会发展成类似HC的包囊，而包囊 Notch的形成取决于Notch的发育途径。缺口信号也已被证明是 对IPF中HC的形成很重要。我们已经发现小鼠中与流感相关的类HC包囊含有 丰富的MUC5B，在人肺上皮细胞系中，Notch抑制显著减少MUC5B 表情。然而，Noch和MUC5B在IPF中的相互作用还完全不清楚。考虑到明显的 Notch在MUC5B和类HC包囊表达中的作用以及MUC5B在人类和 小鼠纤维化模型，我们假设Notch调节肺损伤修复并促进肺损伤 纤维化通过下游MUC5B的表达实现。在本提案的目标1中，我将为Notch在 肺纤维化和MUC5B的表达，通过测试Notch对于任何一个是必要的还是充分的。在AIM 2、我将评估MUC5B在纤维化中的必要性，并确定MUC5B对纤维化的作用是否 上皮细胞固有的。这些目标解决了我们对IPF发病机制的认识上的重大差距，特别是 在上皮细胞方面，并可能导致新的治疗方法。在这个新颖的项目中接受的培训将 加强我对分子生物学的理解，并结合生物信息学的具体课程，将 使我能够专注于间质性肺病的功能遗传学方法。

Project summary The overall scientific goal of this proposal is to build upon our findings in MUC5B-associated idiopathic pulmonary fibrosis (IPF) to understand the basic mechanisms of pulmonary fibrosis. IPF is a devastating disease that claims 5 million lives worldwide annually. It is characterized by progressive lung fibrosis and formation of microscopic honeycomb (HC) cysts. Although some therapies have recently become available, treatment of IPF is limited by our understanding of its pathobiology. We have found that a gain-of-function polymorphism 3kb upstream of the MUC5B gene is the strongest risk factor for development of IPF. In preliminary experiments in mice, we demonstrate that overexpression of Muc5b leads to an enhancement of fibrosis provoked by bleomycin and influenza. However, overexpression of Muc5b without lung injury is not sufficient to provoke fibrosis. Gene expression analysis in IPF has demonstrated an association of MUC5B expression with HC. Likewise, we and others, have discovered that HCs contain significant MUC5B protein. A recent publication noted that mice develop HC-like cysts in the setting of influenza injury, and that cyst formation depends on the Notch developmental pathway. Notch signals have also been demonstrated to be important for HC formation in IPF. We have found that influenza-associated HC-like cysts in mice contain copious Muc5b, and in human lung epithelial cell lines Notch inhibition significantly reduces MUC5B expression. However, the interplay of NOTCH and MUC5B in IPF are completely unknown. Given the apparent role of Notch in the expression of Muc5b and HC-like cysts, and the characterized role of Muc5b in human and murine fibrosis models, we hypothesized that Notch modulates lung injury repair and promotes pulmonary fibrosis through downstream Muc5b expression. In Aim 1 of this proposal, I will establish a role for Notch in pulmonary fibrosis and Muc5b expression by testing whether Notch is necessary or sufficient for either. In Aim 2, I will evaluate the necessity of Muc5b in fibrosis, and determine whether effects of Muc5b on fibrosis are epithelial-cell intrinsic. These Aims address significant gaps in our knowledge of IPF pathogenesis, particularly where epithelia are concerned, and may lead to novel therapies. Training received during this novel project will enhance my understanding of molecular biology, and, paired with specific coursework in bioinformatics, will enable me to focus on functional genetic approaches to interstitial lung disease.