BLOCKADE OF ENDOTHELIAL, BUT NOT EPITHELIAL, CELL EXPRESSION OF PD-L1 FOLLOWING SEVERE SHOCK ATTENUATES THE DEVELOPMENT OF INDIRECT ACUTE LUNG INJURY IN MICE.
严重休克后内皮细胞 (而非上皮细胞) PD-L1 表达的阻断可减弱小鼠间接急性肺损伤的发生。
- 作者列表："Xu S","Yang Q","Bai J","Tao T","Tang L","Chen Y","Chung CS","Fallon EA","Ayala A
:This study sets out to establish the comparative contribution of PD-L1 expression by pulmonary endothelial cells (ECs) and/or epithelial cells (EpiCs) to the development of indirect acute lung injury (iALI) by taking advantage of the observation that treatment with naked siRNA by intra-tracheal (I.T.) delivery in mice primarily effects lung EpiCs, but not lung ECs; while intravenous (I.V.) delivery of liposomal encapsulated siRNA largely targets vascular ECs including the lung, but not pulmonary EpiCs. We showed that, using a mouse model of iALI (induced by hemorrhage followed by septic challenge [Hem-CLP]), PD-L1 expression on pulmonary ECs or EpiCs was significantly up-regulated in the iALI mice at 24h post-septic insult. After documenting the selective ability of I.T. vs. I.V. delivery of PD-L1siRNA to inhibit PD-L1 expression on EpiCs vs. ECs, respectively, we observed that the iALI-induced elevation of cytokine/chemokine levels (in the broncho-alveolar lavage fluid, lung lysates or plasma), lung MPO and caspase-3 activities could largely only be inhibited by I.V., but not I.T. delivery of PD-L1 siRNA. Moreover, I.V., but not I.T., delivery led to a preservation of normal tissue architecture, lessened pulmonary edema and reduced neutrophils influx induced by iALI. In addition, in vitro mouse endothelial cell line studies showed that PD-L1 gene knockdown by siRNA or knockout by CRISPR/Cas9-mediated gene manipulation reduced monolayer permeability and maintained tight junction protein levels upon recombinant IFN-g stimulation. Together, these data imply a critical role for pulmonary vascular ECs in mediating PD-1:PD-L1 driven pathological changes resulting from systemic stimuli such as Hem-CLP.
: 本研究旨在建立肺内皮细胞 (ECs) 和/或上皮细胞 (EpiCs) 表达 PD-L1 在间接急性肺损伤 (iALI) 发生中的比较作用通过利用气管内裸 siRNA 治疗的观察 (I。 t.)小鼠体内的递送主要影响肺 EpiCs，但不影响肺 ECs; 而脂质体包裹的 siRNA 的静脉 (I.V.) 递送主要针对包括肺在内的血管 ECs，但不影响肺 EpiCs。我们发现，使用 iALI 小鼠模型 (由出血诱导，然后是脓毒症攻击 [Hem-CLP]), iALI 小鼠脓毒症后 24 h 肺 ECs 或 EpiCs 上 PD-L1 表达明显上调。在记录了 i.T.与 i.V.传递 PD-L1siRNA 分别抑制 EpiCs 与 ECs 上 PD-L1 表达的选择性能力后, 我们观察到 iALI 诱导的细胞因子/趋化因子水平升高 (在支气管肺泡灌洗液、肺裂解物或血浆中), 肺 MPO 和 caspase-3 活性只能被 I 抑制。 v., 但不是我。 t.递送 PD-L1 siRNA。此外，I.V.，而不是 I.T.，递送导致正常组织结构的保存，减轻肺水肿和减少 iALI 诱导的中性粒细胞内流。此外, 体外小鼠内皮细胞系研究表明，通过 siRNA 敲除 PD-L1 基因或通过 CRISPR/Cas9-mediated 基因操作敲除基因可降低单层通透性，并在重组 IFN-g 刺激下维持紧密连接蛋白水平。总之，这些数据暗示了肺血管 ECs 在介导 PD-1 中的关键作用: 由 Hem-CLP 等全身刺激引起的 PD-L1 驱动的病理变化。
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.