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.

 说明（由申请人提供）：溴（Br 2）是一种高毒性暗红色液体，容易蒸发成红色蒸汽，具有令人窒息的气味。全世界溴的年产量超过30万吨。暴露于Br 2会导致急性肺损伤、呼吸衰竭和纤维化死亡。由于工业和交通事故可能会在人口稠密地区释放大量溴，溴对公众健康构成明显和现实的危险。很少有已发表的研究评价了吸入溴2的急性和慢性后遗症;治疗仍然是对症的，没有有效的对策。与人类病理学相似，小鼠暴露于Br 2会导致反应性气道疾病综合征（RADS）、血气屏障对血浆蛋白的渗透性增加以及炎症，随后是上皮下气道纤维化和显著死亡率。本申请的总体目的是确定负责这些事件的生化和分子机制，并制定适当的对策。我们提出，Br 2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，相互作用和片段，产生高度炎症性的低分子量透明质酸片段（L-HA）。L-HA与CD 44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-β 1和RhoA。这些事件导致RADS、增加的上皮对血浆蛋白的渗透性、气道细胞的上皮-间充质细胞转化（EMT）、上皮下纤维化、呼吸衰竭死亡。此外，我们首次证明了溴化脂质在暴露于Br 2的小鼠的肺和血浆中的形成。这些化合物由Br 2与肺缩醛磷脂相互作用形成，介导和放大Br 2肺损伤，并作为Br 2暴露的生物标志物。基于可靠的数据，我们证实，暴露于Br 2后，雾化吸入Yabro ®（一种H-HA，目前在欧洲进行哮喘临床试验）可减轻肺损伤，增强修复并降低死亡率。在第一个具体目标中提出的实验将评估暴露于Br 2并返回室内空气长达三周的小鼠的生理，生物化学和形态学变化，并测试暴露后雾化施用Yabro的有效性，以减少肺损伤和死亡率。然后，我们将确定Br 2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。我们证实Br 2、溴化脂质和L-HA增加细胞内Ca 2+并激活RhoA，从而导致气道收缩性和上皮通透性增加。实验将：（i）通过膜片钳测定膜电位;（ii）通过fura-2荧光测定细胞内Ca+2;（iii）RhoA和ROCK激活;（iv）肌球蛋白轻链磷酸化;和（v）（对于上皮细胞）对荧光葡聚糖的渗透性。最后，我们将在Br 2暴露后1、24和72小时分离小鼠气管环，并测量平滑肌对乙酰甲胆碱的收缩反应。