Matrix Metalloproteinase-19 as a Mediator of Airway Fibrosis in Obese Allergic Asthma

近40%的哮喘患者人口患有肥胖症。这些患者表现出哮喘加重。 症状和严重程度。肥胖与炎症和代谢变化有关， 会对哮喘的病理生物学有贡献。具体地说，瘦素水平的增加，a 促炎症脂肪因子和胰升糖素样肽1(GLP-1)分泌减少 调节胰岛素产生的荷尔蒙，可能通过作用增强哮喘的发病过程 直接作用于呼吸道结构细胞。在过敏性哮喘中，呼吸道上皮细胞产生 促纤维化介质激活呼吸道成纤维细胞分泌过量细胞外 矩阵(ECM)。这些过程有助于哮喘的气道重塑和结构变化 会导致永久性的呼吸道阻塞。肥胖症患者气道重塑的机制 人们对哮喘知之甚少，但在过敏性哮喘中，这些过程在一定程度上是直接的 通过2型细胞因子白介素13(IL-13)。基质金属蛋白酶-19(MMP19)是 一种过敏原激活的蛋白酶，由呼吸道上皮细胞和成纤维细胞产生， 参与ECM的正常加工。我们的初步数据表明，GLP-1可以刺激 IL-13和瘦素抑制呼吸道细胞产生基质金属蛋白酶-19。我们的假设是肥胖--而且 变应原诱导的抑制基质金属蛋白酶-19的产生在糖尿病的发生发展中起重要作用 过敏性哮喘患者的呼吸道纤维化。此外，GLP-1抑制促纤维化细胞功能，并 抑制肥胖、过敏性人和小鼠呼吸道纤维化的进展 呼吸道成纤维细胞和上皮细胞分泌基质金属蛋白酶-19。为了检验这一假设，我们提出了两个 目标。在目标1中，我们将培养肥胖者和瘦肉者的原代呼吸道上皮细胞和成纤维细胞 过敏性哮喘和肥胖及瘦的非哮喘受试者。我们将让MMP19的表达在 这些细胞使用CRISPR-Cas9并确定基质金属蛋白酶-19在促纤维化细胞功能中的作用 对瘦素、IL-13和GLP-1或GLP-1受体拮抗剂的反应。在目标2中，饮食导致肥胖 Mmp19-I-和Mmp19+I+小鼠将被同时挑战4年的室内尘螨变应原 行垂直袖状胃切除术前数周，诱导GLP-1分泌。我们将评估 活体气道纤维化及其与肺组织GLP-1、瘦素和基质金属蛋白酶-19水平的关系 组织、血清和支气管肺泡灌洗液。我们将评估体外培养的小鼠肺 成纤维细胞产生基质金属蛋白酶-19和细胞外基质。在这两个目标中，我们将把病理性的呼吸道改变联系起来。 和体外细胞对呼吸道生理和肺功能测量的反应，以便 预测呼吸道重塑。成功完成这些目标不仅将增加我们的 了解肥胖过敏性哮喘的病理生物学机制，但也将 测试治疗肥胖哮喘患者的特定干预措施。

Nearly 40% of the asthma patient population is obese. These patients exhibit increased asthma symptoms and severity. Obesity is associated with inflammatory and metabolic changes that can contribute to asthma pathobiology. Specifically, increased levels of leptin, a pro-inflammatory adipokine, and decreased secretion of glucagon-like peptide 1 (GLP-1), a peptide hormone that regulates insulin production, may augment pathogenic processes in asthma by acting directly on airway structural cells. In allergic asthma, airway epithelial cells produce pro-fibrotic mediators that activate airway fibroblasts to secrete excess extracellular matrix (ECM). These processes contribute to airway remodeling, structural changes in asthma that can result in permanent airway obstruction. The mechanisms directing airway remodeling in obese asthma are poorly understood, but in allergic asthma, these processes are directed in part by the type 2 cytokine, interleukin-13 (IL-13). Matrix metalloproteinase-19 (MMP-19) is an allergen-activated protease produced by airway epithelial cells and fibroblasts that participates in normal processing of ECM. Our preliminary data suggest that GLP-1 stimulates, while IL-13 and leptin suppress, MMP-19 production by airway cells. Our hypothesis is that obesity- and allergen-induced suppression of MMP-19 production plays an important role in the development of airway fibrosis in allergic asthma. Furthermore, GLP-1 inhibits pro-fibrotic cellular functions and halts the progression of airway fibrosis in obese, allergic humans and mice by acting to enhance airway fibroblast and epithelial cell MMP-19 secretion. To test this hypothesis, we propose two Aims. In Aim 1, we will culture primary airway epithelial cells and fibroblasts from obese and lean allergic asthmatic and obese and lean non-asthmatic subjects. We will silence MMP19 expression in these cells using CRISPR-Cas9 and determine the role of MMP-19 in pro-fibrotic cellular functions in response to leptin, IL-13 and GLP-1 or a GLP-1 receptor antagonist. In Aim 2, diet-induced obese Mmp19-I- and Mmp19+I+ mice will be concurrently challenged with house dust mite allergen for 4 weeks before undergoing vertical sleeve gastrectomy to induce GLP-1 secretion. We will assess airway fibrosis in vivo and relate these findings to GLP-1, leptin and MMP-19 levels in lung tissue, serum and bronchoalveolar lavage fluid. We will evaluate ex vivo cultured mouse lung fibroblasts for MMP-19 and ECM production. In both aims, we will relate pathologic airway changes and ex vivo cellular responses to measures of airway physiology and lung function in order to predict airway remodeling. Successful completion of these Aims will not only increase our understanding of the mechanisms directing the pathobiology of obese allergic asthma, but also will test specific interventions to treat obese asthma patients.