Platelet Extracellular Vesicles Drive Inflammasome-IL-1β-Dependent Lung Injury in Sickle Cell Disease.
血小板胞外囊泡驱动镰状细胞病的炎性-il-1 β 依赖性肺损伤。
- 作者列表："Vats R","Brzoska T","Bennewitz MF","Jimenez MA","Pradhan-Sundd T","Tutuncuoglu E","Jonassaint J","Gutierrez E","Watkins SC","Shiva S","Scott MJ","Morelli AE","Neal MD","Kato GJ","Gladwin MT","Sundd P
:Rationale: Intraerythrocytic polymerization of Hb S promotes hemolysis and vasoocclusive events in the microvasculature of patients with sickle cell disease (SCD). Although platelet-neutrophil aggregate-dependent vasoocclusion is known to occur in the lung and contribute to acute chest syndrome, the etiological mechanisms that trigger acute chest syndrome are largely unknown.Objectives: To identify the innate immune mechanism that promotes platelet-neutrophil aggregate-dependent lung vasoocclusion and injury in SCD.Methods:In vivo imaging of the lung in transgenic humanized SCD mice and in vitro imaging of SCD patient blood flowing through a microfluidic system was performed. SCD mice were systemically challenged with nanogram quantities of LPS to trigger lung vasoocclusion.Measurements and Main Results: Platelet-inflammasome activation led to generation of IL-1β and caspase-1-carrying platelet extracellular vesicles (EVs) that bind to neutrophils and promote platelet-neutrophil aggregation in lung arterioles of SCD mice in vivo and SCD human blood in microfluidics in vitro. The inflammasome activation, platelet EV generation, and platelet-neutrophil aggregation were enhanced by the presence of LPS at a nanogram dose in SCD but not control human blood. Inhibition of the inflammasome effector caspase-1 or IL-1β pathway attenuated platelet EV generation, prevented platelet-neutrophil aggregation, and restored microvascular blood flow in lung arterioles of SCD mice in vivo and SCD human blood in microfluidics in vitro.Conclusions: These results are the first to identify that platelet-inflammasome-dependent shedding of IL-1β and caspase-1-carrying platelet EVs promote lung vasoocclusion in SCD. The current findings also highlight the therapeutic potential of targeting the platelet-inflammasome-dependent innate immune pathway to prevent acute chest syndrome.
: 原理: Hb S 的红细胞内聚合促进镰状细胞病 (SCD) 患者微血管的溶血和血管闭塞事件。尽管已知血小板-中性粒细胞聚集依赖性血管闭塞发生在肺并导致急性胸部综合征，但触发急性胸部综合征的病因机制在很大程度上是未知的。目的:确定促进 SCD 中血小板-中性粒细胞聚集依赖性肺血管闭塞和损伤的天然免疫机制。方法: 在转基因人源化 SCD 小鼠体内进行肺成像，并对流经微流控系统的 SCD 患者血液进行体外成像。SCD 小鼠用纳克量 LPS 全身性激发肺血管闭塞。测量和主要结果: 血小板炎症小体激活导致 il-1 β 的产生和血小板细胞外囊泡 (EVs) caspase-1-携带型 在体内 SCD 小鼠肺小动脉和体外微流体中 SCD 人血中与中性粒细胞结合并促进血小板-中性粒细胞聚集。SCD 中以纳克剂量存在 LPS，而不是对照人血，炎症小体激活、血小板 EV 生成和血小板-中性粒细胞聚集增强。抑制炎性体效应 caspase-1 或 il-1 β 通路可减弱血小板 EV 生成，阻止血小板-中性粒细胞聚集, 并在体外微流体中恢复 SCD 小鼠体内肺小动脉和 SCD 人血中的微血管血流。结论:这些结果首次证实了血小板炎症小体依赖的 il-1 β 和 caspase-1-携带型血小板 EVs 的脱落促进了 SCD 的肺血管闭塞。目前的发现也强调了靶向血小板炎症小体依赖性天然免疫途径预防急性胸部综合征的治疗潜力。
METHODS:BACKGROUND AND PURPOSE:A critical role for sphingosine kinase/sphingosine-1-phosphate (S1P) pathway in the control of airway function has been demonstrated in respiratory diseases. Here, we address S1P contribution in a mouse model of mild chronic obstructive pulmonary disease (COPD). EXPERIMENTAL APPROACH:C57BL/6J mice have been exposed to room air or cigarette smoke up to 11 months and killed at different time points. Functional and molecular studies have been performed. KEY RESULTS:Cigarette smoke caused emphysematous changes throughout the lung parenchyma coupled to a progressive collagen deposition in both peribronchiolar and peribronchial areas. The high and low airways showed an increased reactivity to cholinergic stimulation and α-smooth muscle actin overexpression. Similarly, an increase in airway reactivity and lung resistances following S1P challenge occurred in smoking mice. A high expression of S1P, Sph-K2 , and S1P receptors (S1P2 and S1P3 ) has been detected in the lung of smoking mice. Sphingosine kinases inhibition reversed the increased cholinergic response in airways of smoking mice. CONCLUSIONS AND IMPLICATIONS:S1P signalling up-regulation follows the disease progression in smoking mice and is involved in the development of airway hyperresponsiveness. Our study defines a therapeutic potential for S1P inhibitors in management of airways hyperresponsiveness associated to emphysema in smokers with both asthma and COPD.
METHODS::The interim results from this 90-day multi-dose, inhalation toxicology study with life-time post-exposure observation has shown an important fundamental difference in persistence and pathological response in the lung between brake dust derived from brake-pads manufactured with chrysotile, TiO2 or chrysotile alone in comparison to the amphiboles, crocidolite and amosite asbestos. In the brake dust exposure groups no significant pathological response was observed at any time. Slight macrophage accumulation of particles was noted. Wagner-scores, were from 1 to 2 (1 = air-control group) and were similar to the TiO2 group. Chrysotile being biodegradable, shows a weakening of its matrix and breaking into short fibers & particles that can be cleared by alveolar macrophages and continued dissolution. In the chrysotile exposure groups, particle laden macrophage accumulation was noted leading to a slight interstitial inflammatory response (Wagner-score 1-3). There was no peribronchiolar inflammation and occasional very slight interstitial fibrosis. The histopathology and the confocal analyses clearly differentiate the pathological response from amphibole asbestos, crocidolite and amosite, compared to that from the brake dust and chrysotile. Both crocidolite and amosite induced persistent inflammation, microgranulomas, and fibrosis (Wagner-scores 4), which persisted through the post exposure period. The confocal microscopy of the lung and snap-frozen chestwalls quantified the extensive inflammatory response and collagen development in the lung and on the visceral and parietal surfaces. The interim results reported here, provide a clear basis for differentiating the effects from brake dust exposure from those following amphibole asbestos exposure. The subsequent results through life-time post-exposure will follow.
METHODS::The respiratory tract is lined by a pseudo-stratified epithelium from the nose to terminal bronchioles. This first line of defense of the lung against external stress includes five main cell types: basal, suprabasal, club, goblet and multiciliated cells, as well as rare cells such as ionocytes, neuroendocrine and tuft/brush cells. At homeostasis, this epithelium self-renews at low rate but is able of fast regeneration upon damage. Airway epithelial cell lineages during regeneration have been investigated in the mouse by genetic labeling, mainly after injuring the epithelium with noxious agents. From these approaches, basal cells have been identified as progenitors of club, goblet and multiciliated cells, but also of ionocytes and neuroendocrine cells. Single-cell RNA sequencing, coupled to lineage inference algorithms, has independently allowed the establishment of comprehensive pictures of cell lineage relationships in both mouse and human. In line with genetic tracing experiments in mouse trachea, studies using single-cell RNA sequencing (RNAseq) have shown that basal cells first differentiate into club cells, which in turn mature into goblet cells or differentiate into multiciliated cells. In the human airway epithelium, single-cell RNAseq has identified novel intermediate populations such as deuterosomal cells, 'hybrid' mucous-multiciliated cells and progenitors of rare cells. Novel differentiation dynamics, such as a transition from goblet to multiciliated cells have also been discovered. The future of cell lineage relationships in the respiratory tract now resides in the combination of genetic labeling approaches with single-cell RNAseq to establish, in a definitive manner, the hallmarks of cellular lineages in normal and pathological situations.