Regulation of alveolar epithelial homeostasis in acute lung injury

描述(申请人提供)：该项目旨在确定在2009年H1N1大流行流感病毒引起的急性肺损伤中，人类肺上皮细胞动态平衡是如何调节的。由于H1N1大流行病毒的快速传播和高致病性，迫切需要了解宿主对病毒感染的反应。这种病毒以远端肺细胞为目标，导致比季节性流感病毒更严重的疾病，包括弥漫性肺泡损伤和肺水肿。为了明确这种组织损伤的机制，研究TE病毒感染的特定细胞是很重要的。因此，我们的研究将集中在人类肺泡区的细胞上。我们的 方法是新颖的，因为我们将研究2009年H1N1大流行病毒对从相同健康肺捐赠者分离的人肺泡上皮细胞和肺泡巨噬细胞原代培养的影响。我们使用这个系统的初步数据表明，AIM2炎症体和细胞因子TSLP都参与了宿主对流感病毒感染的反应。AIM2炎症体对宿主抵抗细菌和DNA病毒感染具有重要作用，但它在RNA病毒感染中的作用尚未确定。在这里，我们将确定AIM2炎症体在原代人类ATII细胞和在H1N1流感诱导的上皮损伤的小鼠模型中的功能和机制。我们推测AIM2是流感病毒在肺泡上皮细胞中诱导的主要炎症体。AIM2缺陷细胞和AIM2缺陷小鼠在流感感染过程中会有更多的上皮屏障损伤。TSLP在哮喘等过敏性疾病中发挥关键作用，但其对上皮屏障的影响尚未确定。我们将使用体外和体内模型来确定TSLP在流感感染期间保护肺泡上皮屏障中的作用。我们推测炎性小体的激活将促进肺泡上皮细胞产生TSLP。流感刺激的TSLP将通过增强细胞之间的紧密连接和/或刺激上皮细胞来改善流感在体外和体内所破坏的屏障 扩散。此外，肺泡上皮细胞与巨噬细胞之间的细胞间相互作用将促进上皮细胞释放TSLP。我们的研究将揭示流感急性肺损伤期间肺泡上皮屏障调节的新机制，从而揭示降低流感诱导死亡率的潜在治疗策略。

DESCRIPTION (provided by applicant): This project aims to determine how human lung epithelial homeostasis is regulated in acute lung injury induced by the 2009 H1N1 pandemic influenza virus. Because of the rapid transmission and high potential for increased pathogenicity of the H1N1 pandemic virus, there is an urgent need to understand the host response against viral infection. This virus targets distal lung cells and causes more severe disease than seasonal influenza virus, including diffuse alveolar damage and pulmonary edema. To define the mechanism of this tissue injury, it is important to study the specific cells that are infected by te virus. Therefore, our studies will focus on the cells in the alveolar region of the human lung. Our approach is novel in that we will study the effect of 2009 H1N1 pandemic virus on primary cultures of human alveolar epithelial cells and alveolar macrophages isolated from the same healthy lung donors. We have preliminary data using this system that suggests the involvement of both the AIM2 inflammasome and the cytokine TSLP in host response to influenza virus infection. The AIM2 inflammasome is important for host defense against bacteria and DNA virus infection, but a role for it in RNA virus infection has not previously been identified. Here we wil determine the function and mechanism of the AIM2 inflammasome in primary human ATII cells and in a mouse model during H1N1 influenza-induced epithelial injury. We hypothesize that AIM2 is the primary inflammasome induced by influenza virus in alveolar epithelial cells. AIM2 deficient cells and AIM2 deficient mice will have more impairment of the epithelial barrier during influenza infection. TSLP plays a key role in allergic diseases such as asthma, but its effect on the epithelial barrier is not yet defined. We will determine the role of TSLP in protecting the alveolar epithelial barrier during influenza infection using both in vitro and in vivo models. We hypothesize that inflammasome activation will enhance the TSLP production by alveolar epithelial cells. Influenza-stimulated TSLP will improve the damaged barrier by influenza both in vitro and in vivo through enhancing the tight junctions between cells and/or stimulating epithelial proliferation. In addition, the cell-cell interaction between alveolar epithelial cells and macrophages will enhance the release of TSLP by epithelial cells. Our study will reveal novel mechanisms for the regulation of the alveolar epithelial barrier during acute lung injury by influenza, thereby uncovering potential novel therapeutic strategies for reducing influenza-induced mortality.