Bromine Inhalation Induced Lung Injury: Novel Mechanisms and Treatment Strategies

溴吸入引起的肺损伤：新机制和治疗策略

• 批准号: 9567726
• 负责人: Sadis Matalon
• 金额: $ 14.84万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-15 至 2020-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9567726
• 关键词: Accidents; Acetylcholine; Acids; Acute; Acute Lung Injury; Adult; Aerosols; Air; Airway Resistance; Aldehydes; Alveolar; Animal Model; Area; Asthma; Attenuated; Binding; Biochemical; Biological Markers; Blood gas; Breathing; Bromine; CD44 gene; Cells; Cessation of life; Chronic; Clinical Trials; Darkness; Data; Development; Dextrans; Disease; Disinfection; Effectiveness; Environment; Epithelial; Epithelial Cells; Europe; Event; Exposure to; Fiber; Fibrosis; Flame Retardants; Fluorescence; Fura-2; Gases; Gasoline; Glycosaminoglycans; Guanosine Triphosphate Phosphohydrolases; Halogens; Human; Human Pathology; Hyaluronan; Industrial Accidents; Industrialization; Inflammation; Inflammatory; Injury; Insecticides; Irrigation; Lead; Lipids; Liquid substance; Lung; Measurement; Measures; Mediating; Mediator of activation protein; Membrane Potentials; Mesenchymal; Molecular; Molecular Weight; Morphology; Mus; Muscle Cells; Muscle Contraction; Myosin Light Chains; Nose; Odors; Permeability; Phosphorylation; Physiological; Plasma; Plasma Proteins; Plasmalogens; Production; Public Health; Publishing; Pulmonary Edema; Pulmonary Fibrosis; Respiratory Failure; Rodent; Site; Small Interfering RNA; Smooth Muscle; Smooth Muscle Myocytes; Solid; Specific qualifier value; Structure of parenchyma of lung; Survivors; Syndrome; TLR4 gene; Testing; Time; Toxic effect; Transportation; Trypsin Inhibitors; Validation; Water; Wild Type Mouse; aerosolized; alveolar type II cell; base; cytokine; eosinophil; eosinophil peroxidase; experimental study; hypobromous acid; inhibitor/antagonist; inter-alpha-inhibitor; lung injury; male; methacholine; mortality; novel; palliative; patch clamp; public health relevance; repaired; respiratory smooth muscle; response; treatment strategy; vapor

 DESCRIPTION (provided by applicant): Bromine (Br2) is a highly toxic dark-reddish liquid, which evaporates readily to a red vapor with a suffocating odor. World production of Br2 exceeds 300,000 tons per year. Exposure to Br2 causes acute lung injury, death from respiratory failure, and fibrosis. Because of the potential for industrial and transportation accidents to release of large amounts of Br2 in populated areas, Br2 presents a clear and present danger to public health. Few published studies have evaluated the acute and chronic sequelae of Br2 inhalation; treatment remains symptomatic and no effective countermeasures exist. Similar to human pathology, exposure of mice to Br2 causes reactive airway disease syndrome (RADS), increased permeability of the blood gas barrier to plasma proteins, and inflammation followed by sub-epithelial airway fibrosis and significant mortality. The overall purpose of this application is to identify the biochemical and molecular mechanisms responsible for these events and develop appropriate countermeasures. We propose that Br2 and hypobromous acid (HOBr-) interact with and fragment high molecular weight hyaluronan (H-HA), a ubiquitous matrix glycosaminoglycan, to generate highly inflammatory low molecular weight hyaluronan fragments (L-HA). L- HA binds to CD44 and Toll like receptor (TLR)-4, increases intracellular Ca+2 and activates TGF-1, and RhoA in lung epithelial and airway smooth muscle cells. These events lead to RADS, increased epithelial permeability to plasma proteins, epithelial-mesenchymal cell transition (EMT) of airway cells, sub-epithelial fibrosis, an death from respiratory failure. In addition, we demonstrate for the first time the formation of brominated lipids in the lungs and plasma of mice exposed to Br2. These compounds, formed by the interaction of Br2 with lung plasmalogens, mediate and amplify Br2 lung injury and act as biomarkers of Br2 exposure. Based on solid data we posit that post-Br2 exposure administration of aerosolized Yabro (a form of H-HA, currently in clinical trials in Europe for asthma), attenuates lung damage, enhances repair and decreases mortality. Experiments proposed in the first specific aim will assess physiological, biochemical, and morphological changes in mice exposed to Br2 and returned to room air for up to three weeks and test the effectiveness of aerosolized Yabro administered post exposure to decrease lung injury and mortality. We will then identify the mechanisms by which Br2 damages rodent and human airway smooth muscle (ASM), bronchial and alveolar type II (ATII) cells. We posit that Br2, brominated lipids, and L-HA increase intracellular Ca2+ and activate RhoA, which lead to increased airway contractility and epithelial permeability. Experiments will: (i) determine membrane potentials by patch clamp; (ii) intracellular Ca+2 by fura-2 fluorescence; (iii) RhoA and ROCK activation; (iv) myosin light chain phosphorylation; and (v) (for epithelial cells) permeability to fluorescent dextrans. Finally, we wll isolate mouse tracheal rings at 1, 24, and 72 hr. post Br2 exposure and measure smooth muscle contraction in response to methacholine.

 描述（申请人提供）： 溴（Br2）是一种剧毒的深红色液体，很容易蒸发成红色蒸气，具有令人窒息的气味。世界 Br2 产量每年超过 30 万吨。接触 Br2 会导致急性肺损伤、呼吸衰竭和纤维化导致的死亡。由于工业和交通事故可能会在人口稠密地区释放大量 Br2，因此 Br2 对公众健康构成明显且现实的危险。很少有已发表的研究评估了吸入 Br2 的急性和慢性后遗症；治疗仍然是对症治疗，没有有效的对策。与人类病理学类似，小鼠暴露于 Br2 会导致反应性气道疾病综合征 (RADS)、血气屏障对血浆蛋白的通透性增加以及炎症，随后导致上皮下气道纤维化和显着死亡率。该应用程序的总体目的是确定导致这些事件的生化和分子机制并制定适当的对策。我们提出，Br2 和次溴酸 (HOBr-) 与高分子量透明质酸 (H-HA)（一种普遍存在的基质糖胺聚糖）相互作用并使其片段化，产生高度炎症性的低分子量透明质酸片段 (L-HA)。 L-HA 与 CD44 和 Toll 样受体 (TLR)-4 结合，增加细胞内 Ca+2 并激活肺上皮和气道平滑肌细胞中的 TGF-β1 和 RhoA。这些事件导致 RADS、上皮对血浆蛋白的通透性增加、气道细胞的上皮-间质细胞转化 (EMT)、上皮下纤维化、呼吸衰竭死亡。此外，我们首次证明了暴露于 Br2 的小鼠肺部和血浆中溴化脂质的形成。这些化合物由 Br2 与肺缩醛磷脂相互作用形成，介导和放大 Br2 肺损伤，并作为 Br2 暴露的生物标志物。基于可靠的数据，我们认为 Br2 暴露后给予雾化 Yabro（H-HA 的一种形式，目前在欧洲正在进行哮喘临床试验）可减轻肺损伤、增强修复并降低死亡率。第一个具体目标中提出的实验将评估暴露于 Br2 并返回室内空气长达三周的小鼠的生理、生化和形态变化，并测试暴露后施用雾化 Yabro 降低肺损伤和死亡率的有效性。然后我们将确定 Br2 损害啮齿动物和人类气道平滑肌 (ASM)、支气管和肺泡 II 型 (ATII) 细胞的机制。我们假设 Br2、溴化脂质和 L-HA 会增加细胞内 Ca2+ 并激活 RhoA，从而导致气道收缩力和上皮通透性增加。实验将：（i）通过膜片钳测定膜电位； (ii) 通过 fura-2 荧光检测细胞内 Ca+2； (iii) RhoA 和 ROCK 激活； (iv) 肌球蛋白轻链磷酸化； (v)（对于上皮细胞）对荧光葡聚糖的渗透性。最后，我们将在 1、24 和 72 小时分离小鼠气管环。 Br2 暴露后并测量乙酰甲胆碱反应的平滑肌收缩。