Herpesvirus infection/injury govern fibrocyte recruitment and activation

项目摘要/摘要 肺纤维化可能是由于连续肺损伤引起的伤口愈合反应失调所致。 循环中的骨髓间充质前体细胞(纤维细胞)的募集对于 损伤后纤维增殖性宿主反应。纤维细胞有助于细胞外基质(ECM)的生成和 通过分泌促纤维化/促炎因子来促进纤维化。局灶性肺泡上皮细胞 (AEC)损伤被认为是纤维化过程的始动事件。肺损伤的病因有 未知但潜伏的病毒感染，特别是疱疹病毒亚科成员的感染与 特发性肺纤维化(IPF)。病毒感染可能通过裂解成纤维细胞影响纤维增殖反应 或通过诱导驻留或招募的细胞的功能改变(S)。感染性疾病 感染MHV-68(一种小鼠伽马疱疹病毒)的小鼠导致AECs和模拟物的裂解和潜伏感染 人类感染Epstein-Barr病毒(EBV)。我们的初步数据显示1)MHV-68感染 在纤维化前后同时给予异硫氰酸荧光素(FITC)可增强FITC诱导的肺纤维化 侮辱。2)MHV-68感染后，成纤维细胞被募集到肺内。3)MHV-68感染导致 半胱氨酰白三烯(Cys Lts)的产生，可诱导纤维细胞的迁移和激活。 4)MHV-68能感染成纤维细胞并促进其增殖。5)慢性肺泡炎致肺泡损伤 FITC，诱导失调的细胞因子和二十烷类化合物反应，有利于纤维细胞的增殖， 分化和细胞外基质沉积。我们假设MHV-68后肝纤维化增加 感染/FITC损伤是增强的招募、增殖和分化的结果 纤维细胞。由于Cys、LTs和CC趋化因子的释放，募集和增殖增加 通过肺内的常驻细胞。通过产生改变的纤维细胞比率来促进分化 实质细胞和募集细胞的刺激和保护分子。完成以下工作 具体的目的将提供关于导致产生或加剧 肺纤维化。目的1)探讨肺泡型MHV-68感染在肺泡型MHV-68感染中的作用。 FITC诱导的肺纤维化；目的2)确定MHV-68感染是否改变前- 或由AECs、肺泡巨噬细胞(AM)、间质巨噬细胞(IMS)和B细胞等抗纤维化介质和 对感染EBV的人AM进行相关研究；目的3)确定MHV-68 无论MHV-68或EBV感染改变纤维细胞和成纤维细胞，感染都会将更多的纤维细胞招募到肺中 探讨半胱氨酸氨基转移酶在MHV-68诱导的纤维细胞募集和纤维化增强中的作用。项目说明/相关性 这项申请中提出的实验将提供对病毒感染的作用的机械性洞察 可能在促使人们发展成纤维化方面起到一定作用。研究还将解决病毒的作用 感染在已有纤维化的患者中起到了加剧疾病的作用。最后，这项工作将探索 限制病毒诱导的纤维化恶化的抗白三烯策略的治疗潜力。

Project Summary/Abstract Pulmonary fibrosis may result from dysregulated wound healing responses to sequential lung injuries. Recruitment of circulating bone-marrow-derived mesenchymal precursors (fibrocytes) is crucial for a fibroproliferative host response post-injury. Fibrocytes contribute to extracellular matrix (ECM) generation and promote fibrosis through the secretion of profibrotic/proinflammatory factors. A focal alveolar epithelial cell (AEC) injury is believed to be the initiating event of the fibrotic process. The etiologic agents of lung injury are unknown but latent viral infections, especially by members of the herpesvirinae have been associated with idiopathic pulmonary fibrosis (IPF). Viral infection might influence fibroproliferative responses via lysis of parenchymal lung cells or by inducing alterations in the function(s) of resident or recruited cells. Infection of mice with MHV-68 (a murine gammaherpesvirus) results in both lytic and latent infection of AECs and mimics human infection with Epstein-Barr virus (EBV). Our preliminary data demonstrate 1) MHV-68 infection augments fluorescein isothiocyanate (FITC)-induced lung fibrosis when given both prior to or after the fibrotic insult. 2) Fibrocytes are recruited to the lung in response to MHV-68 infection. 3) MHV-68 infection results in the generation of cysteinyl leukotrienes (cys LTs) which can induce migration and activation of fibrocytes. 4) MHV-68 can infect fibrocytes and enhance their proliferation. 5) The additional alveolar injury induced by FITC, induces a dysregulated cytokine and eicosanoid response which favors fibrocyte proliferation, differentiation and ECM deposition. We hypothesize that increased fibrosis following MHV-68 infection/FITC injury is the result of enhanced recruitment, proliferation and differentiation of fibrocytes. Recruitment and proliferation are increased due to releases of cys LTs and CC chemokines by resident cells of the lung. Differentiation is enhanced by production of altered ratios of fibrocyte stimulatory and protective molecules by parenchymal and recruited cells. Completion of the following specific aims will provide new information regarding mechanisms that lead to generation of or exacerbation of pulmonary fibrosis. Aim 1) To determine the kinetics and role of alveolar MHV-68 infection in augmentation of FITC-induced pulmonary fibrosis; Aim 2) To determine whether MHV-68 infection alters the secretion of pro- or anti-fibrotic mediators by AECs, alveolar macrophages (AMs), interstitial macrophages (IMs) and B cells and to perform correlative studies in human AMs infected with EBV; Aim 3) To determine whether MHV-68 infection recruits more fibrocytes to the lung, whether MHV-68 or EBV infection alters fibrocytes and fibroblasts and to determine the role of cys LTs in MHV-68-induced recruitment of fibrocytes and augmentation of fibrosis. Project Narrative/Relevance The experiments proposed in this application will provide mechanistic insight into the role that viral infections may play in predisposing people to the development of fibrosis. Research will also address the role that viral infections play in exacerbating disease in patients with established fibrosis. Finally, this work will explore the therapeutic potential of anti-leukotriene strategies to limit viral-induced exacerbations of fibrosis.