Immunopathogenesis in fungal asthma

真菌性哮喘的免疫发病机制

• 批准号: 10580779
• 负责人: Chad Steele
• 金额: $ 49.06万
• 依托单位: TULANE UNIVERSITY OF LOUISIANA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-12-08 至 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10580779
• 关键词: Allergens; Allergic; Apoptosis; Aspergillus fumigatus; Asthma; Attention; Binding; Bone Marrow; CHI3L1 gene; Cell Wall; Cells; Chimera organism; Chitin; Chitin Synthase; Chitinase; Chronic; Chronic Obstructive Pulmonary Disease; Clinical; Collaborations; Cystic Fibrosis; Data; Dictyoptera; Epithelial Cells; Exposure to; Fluorescein-5-isothiocyanate; Funding; Generations; Homologous Gene; Human; Immune; Immune response; Immunologics; In Vitro; Inflammation; Innate Immune Response; Label; Lung; Lung Lavage Fluid; Lung diseases; Mammals; Mediating; Mediator; Mus; National Heart, Lung, and Blood Institute; Particle Size; Physiological Processes; Polysaccharides; Proteins; Publishing; Pyroglyphidae; Reporter; Reporting; Research; Role; Sampling; Severities; Severity of illness; Smooth Muscle Myocytes; Sputum; Therapeutic; Translating; acidic mammalian chitinase; asthmatic; atopy; exoskeleton; fungus; immunoreactivity; immunoregulation; improved; in vivo; mutant; negative affect; overexpression; particle; programs; protein function; pulmonary function; respiratory smooth muscle; response

The objective of this competitive renewal R01 is to continue to uncover mechanisms that contribute to the severity of disease in the nearly 40% of severe asthmatics who are sensitized to fungi. Chitin, a polysaccharide found in the fungal cell wall and the exoskeletons of house dust mites and cockroaches, has garnered attention as a potential immunoreactive allergen. Mammals have evolved to express chitin-degrading chitinases (acidic mammalian chitinase and chitotriosidase) and chitin-binding chitinase-like proteins (YKL-40 in humans, BRP-39 in mice) that may modulate immune responses to chitin. Our recently published data demonstrated that chronic fungal exposure in acidic mammalian chitinase (AMCase) deficient mice resulted in lower AHR in the presence of lower type 17 responses (Infect Immun 86:e0094, 2018). These observations prompted the question how can lack of chitin degradation in the absence of AMCase result in better lung function and less inflammation? Put another way, how can putatively higher chitin content in the lung during fungal asthma be beneficial? Based on studies reporting that different chitin particle sizes induced different immune responses, we posited that the generation of some chitin particles in vivo results in responses that regulate rather than promote inflammation. Preliminary data demonstrates that chitin particle sizes (detected by a FITC-labeled chitin binding domain in lung lavage fluid) are different between asthmatic WT and AMCase deficient mice, with some sizes increased and some decreased. Studies in Aim 1 will further examine chitin particle sizes in mice with normal, absent and overexpressed AMCase and correlate these with immune responses that positively or negatively regulate type 17 responses. In other data, mice deficient in the murine homologue of YKL-40 (BRP-39, Chi3l1-/-) demonstrated worse AHR during fungal asthma, despite lower type 2 responses. Bone marrow chimera studies confirmed these findings and demonstrated that BRP-39 expression in either the immune or non-immune compartment resulted in better AHR compared to the dual absence of BRP-39 expression in both compartments. Studies in Aim 2 will further determine immune and non-immune responses modulated by BRP-39 chitin binding. We further show that chronic exposure to pure A. fumigatus chitin results in the induction of type 1 and type 17, but not type 2, responses. Overall, our hypothesis is that during chronic lung exposure to live fungi, AMCase degrades chitin into various sizes, some of which may drive responses that enhance AHR. In contrast, BRP-39 functions to bind chitin, resulting in a response(s) that regulate/reduce AHR. The specific aims of the proposal are: (1) to define mechanisms of AMCase-mediated immunopathogenesis during fungal asthma, (2) to define mechanisms of BRP-39-mediated modulation of fungal asthma severity and (3) to examine chitinase and chitinase-like protein levels in lung samples from human asthmatics sensitized to fungi.

这种竞争性更新R01的目的是继续发现有助于严重性的机制 在对真菌敏感的严重哮喘患者中，近40％的疾病。几丁质，在 真菌细胞壁和房屋尘螨和蟑螂的外骨骼，引起了人们的关注 潜在的免疫反应性过敏原。哺乳动物已经演变为表达降解蛋白的几丁质酶（酸性 哺乳动物几丁质酶和几丁二酶）和几丁质结合几丁质酶样蛋白（人类的YKL-40，BRP-39 在小鼠中）可能调节对几丁质的免疫反应。我们最近发布的数据表明慢性 酸性哺乳动物几丁质酶（amcase）缺乏小鼠的真菌暴露导致较低的AHR在存在下 较低的17型反应（Infect Immun 86：E0094，2018）。这些观察提出了一个问题 在缺乏amcase的情况下，缺乏几丁质降解会导致肺功能更好，炎症较少？放 另一种方式，在真菌哮喘期间，如何在肺中推动更高的几丁质含量是有益的？基于 研究报告说，不同的几丁质粒度诱导了不同的免疫反应，我们认为 在体内产生一些几丁质颗粒会导致调节而不是促进炎症的反应。 初步数据证明了几丁质粒度（通过肺中的FITC标记的几丁质结合结构域检测 灌洗液）在哮喘WT和amcase不足的小鼠之间有所不同，其中一些尺寸增加了，并且 有些减少。 AIM 1中的研究将进一步检查正常，不存在和 过表达的amcase并将其与负面调节类型的免疫反应相关联 17个回应。在其他数据中，YKL-40（BRP-39，CHI3L1 - / - ）缺乏鼠类同源物的小鼠 尽管2型反应较低，但在真菌哮喘期间的AHR更糟。骨髓嵌合体研究证实 这些发现并证明了BRP-39在免疫或非免疫室中的表达 与两个隔室中BRP-39表达的双重缺失相比，可以使AHR更好。研究 AIM 2将进一步确定由BRP-39几丁质结合调节的免疫和非免疫反应。我们进一步 表明长期暴露于纯曲霉壳蛋白会导致1型和17型的诱导 2，回答。总体而言，我们的假设是，在慢性肺暴露于活真菌期间，amcase降解 几片分解为各种尺寸，其中一些可能会驱动增强AHR的反应。相反，BRP-39 结合几丁质的功能，导致调节/减少AHR的反应。特定目标 建议是：（1）定义在真菌哮喘期间的Amcase介导的免疫病发生的机制，（2）至 定义BRP-39介导的真菌哮喘严重程度调节的机制，以及（3）检查几丁质酶和 来自人类哮喘患者的肺样品中的几丁质酶样蛋白水平对真菌敏感。