Distinct regulation of pulmonary inflammation by isoforms of Interleukin-33

描述(由申请人提供)： 肺部炎症和纤维化，通常被称为“间质性肺病”(ILD)，使人虚弱，甚至致命。ILD的发生可能有多种原因，目前尚无确切的治疗方法，ILD是硬皮病患者的主要死亡原因，而另一种ILD--特发性肺纤维化(IPF)患者的中位生存期仅为2-3年。军队暴露、衰老和自身免疫性疾病使ILD在退伍军人中普遍存在。尽管在揭示ILD的发病机制方面已经取得了很大进展，但对该病的了解仍然很少。最近的发现表明，高内皮微静脉来源的核因子(NFHEV)，也被称为白介素33(IL-33)，在硬皮病和IPF的发病机制中。NFHEV/IL-33因其双重生物学特性而被称为NFHEV/IL-33。作为一种核因子，它在多种细胞类型中表达，并直接与DNA结合。作为一种细胞因子，蛋白水解性激活的细胞外IL-33是Th2反应的强大诱导者，如过敏和哮喘。IL-33细胞因子的后一种活性不活跃 然而，以前对NFHEV作为核因子的活性认识不足，也没有足够详细的研究或与疾病过程相关的研究。我们的数据表明，作为一个核因素，NFHEV推动了ILD。NFHEV在ILD患者的肺部升高，并高于IL-33形式。在这些患者中，NFHEV在炎症细胞中表达，尤其是成纤维细胞，这是ILD发病机制的核心。与此一致的是，在ILD的博莱霉素模型中，NFHEV在小鼠的肺组织中的表达增加。NFHEV在细胞培养和动物模型中的基因传递导致MCP-1、IL-6、MMP3、MMP10和MMP13的产生增加，所有这些都被认为是ILD的致病因素。NFHEV的基因传递也会引起炎症和局部胶原沉积。虽然患者的细胞外IL-33也可能有所升高，但同时伴有可溶性T1/ST2的升高，它中性化了IL-33的细胞因子活性，但对NFHEV的功能没有影响。在博莱霉素模型中，T1/ST2基因缺陷对ILD的严重程度有极小的减轻作用。基于这些数据，这一建议的假设是NFHEV是ILD的一个中心的T1/ST2非依赖性调节因子，通过刺激促炎症和促纤维化基因的表达发挥作用。如果成功验证NFHEV的这一作用，这项研究将为NFHEV靶向策略的未来发展奠定基础，从而导致更好的ILD治疗方法。为了评估这一假设的有效性，将解决三个具体目标。目的1证明，在博莱霉素间质性肺疾病模型中，NFHEV通过T1/ST2非依赖的促炎症和促纤维化基因表达来加重肺部炎症和纤维化。目的2是通过确定NFHEV普遍存在和/或细胞类型特异性缺陷是否能保护间质性肺疾病博莱霉素模型中的肺部炎症和纤维化，以确定重要的病理生理学意义上的NFHEV表达细胞类型。这个目标将利用具有可诱导的细胞类型特异性NFHEV基因敲除的小鼠。目的3将利用IPF患者肺部炎症和纤维化的空间异质性，确定NFHEV的高表达是否与活跃的纤维化灶、细胞炎症和候选NFHEV驱动的促炎和促纤维化因子的表达有关。这项工作调查了与退伍军人中流行的一种致命肺部疾病相关的NFHEV生物学的未知方面。这一结果将为未来在退伍军人和普通人群中开发NFHEV靶向疗法奠定基础。因此，这项提议直接满足退伍军人的需求，并为退伍军人医疗保健任务做出贡献。

DESCRIPTION (provided by applicant): Combined pulmonary inflammation and fibrosis, often referred to as "interstitial lung disease" (ILD), is debilitat- ing and even deadly. ILD may develop for a variety of reasons, and with no confirmed therapies, ILD is the main cause of death in patients with scleroderma, whereas median survival is only 2 to 3 years in patients with another ILD, idiopathic pulmonary fibrosis (IPF). Military exposures, aging, and autoimmune diseases make ILD prevalent in Veterans. Although much progress has been made in uncovering the mechanisms of ILD, the disease still remains poorly understood. Recent findings implicate nuclear factor from high endothelial venules (NFHEV), also known as interleukin (IL)-33, in the pathogenesis of scleroderma and IPF. NFHEV/IL-33 is des- ignated by these two different names because of its dual biology. As a nuclear factor, it is expressed in a varie- ty of cell types and binds directly to DNA. As a cytokine, proteolytically activated extracellular IL-33 is a power- ful inducer of Th2 responses, such as those in allergies and asthma. The latter activities of the IL-33 cytokine are under active investigation, whereas the former activities of NFHEV as a nuclear factor have been underap- preciated and not studied in sufficient detail or in association with a disease process. Our data suggest that, as a nuclear factor, NFHEV drives ILD. NFHEV is elevated in the lungs of patients with ILD and predominant over the IL-33 form. In these patients, NFHEV is expressed in inflammatory cells and, notably, fibroblasts, which are central to the pathogenesis of ILD. Consistent with this, the expression of NFHEV is elevated in the lungs of mice in the bleomycin model of ILD. Gene delivery of NFHEV in cell culture and in the animal model leads to increased production of MCP-1, IL-6, MMP3, MMP10, and MMP13, all of which are known to contribute to ILD. Gene delivery of NFHEV also induces inflammation and local collagen deposition. Although extracellular IL-33 in patients may also be somewhat elevated, there is an accompanying elevation in soluble T1/ST2, which neu- tralizes IL-33 cytokine activity but has no effect on the function of NFHEV. Gene deficiency of T1/ST2 has min- imal if any attenuating effect on the severity of ILD in the bleomycin model. Based on these data, the Hypothe- sis of this proposal is that NFHEV is a central T1/ST2-independent regulator of ILD, acting through stimulation of proinflammatory and profibrotic gene expression. If successful in validating this role of NFHEV, this study will lay the groundwork for future development of NFHEV-targeting strategies and thus lead to better therapies for ILD. To assess the validity of this Hypothesis, three Specific Aims will be addressed. Aim 1 is to prove, in the bleomycin model of interstitial lung disease, that NFHEV worsens pulmonary inflammation and fibrosis through T1/ST2-independent regulation of proinflammatory and profibrotic gene expression. Aim 2 is to define pathophysiologically important NFHEV-expressing cell types by determining whether ubiquitous and/or cell type-specific deficiency of NFHEV protects against pulmonary inflammation and fibrosis in the bleomycin mod- el of interstitial lung disease. This Aim will utilize mice with inducible cell type-specific NFHEV gene knockout. Aim 3 will take advantage of the spatial heterogeneity of inflammation and fibrosis in the lungs of human pa- tients with IPF to determine whether increased expression of NFHEV is associated with active fibrotic foci, cel- lular inflammation, and expression of candidate NFHEV-driven proinflammatory and profibrotic factors. This work investigates unknown aspects of NFHEV biology in association with a deadly lung disease prevalent in Veterans. The results will lay the groundwork for future development of NFHEV-targeting therapies in Veterans and in the general population. Thus, this proposal directly addresses the needs of Veterans and contributes to the VA Healthcare Mission.