Delayed Akt suppression in the lipopolysaccharide-induced acute lung injury promotes resolution that is associated with enhanced effector regulatory T-cells.
脂多糖诱导的急性肺损伤中延迟 Akt 抑制可促进与增强效应调节性 T 细胞相关的分辨率。
- 作者列表："Artham S","Verma A","Alwhaibi A","Adil MS","Manicassamy S","Munn DH","Somanath PR
:The adaptive immune response could play a major role in the resolution of lung injury. Although regulatory T-cells (Tregs) have been implicated in promoting the resolution of lung injury, therapeutic strategies to enhance Treg quantity and activity at the site of injury needs further exploration. In the current study, Akt inhibition using triciribine (TCBN), given 48 hours after lipopolysaccharide (LPS) administration increased Tregs promoted resolution of acute lung injury (ALI). TCBN treatment enhanced the resolution of LPS-induced ALI on day 7 by reducing pulmonary edema and neutrophil activity associated with an increased number of CD4+/FoxP3+/CD103+ and CTLA4+ effector Tregs specifically in the injured lungs and not in the spleen. Treatment of EL-4 T-lymphocytes with two Akt inhibitors (TCBN and MK-2206) for 72 hours resulted in increased FoxP3 expression in vitro. On the other end, Treg-specific PTEN knockout (PTENTreg KO) mice that have a higher Akt activity in its Tregs exhibited a significant impairment in ALI resolution, increased edema and neutrophil activity associated with a reduced number of CD4+/FoxP3+/CD103+ and CTLA4+ effectorTregs as compared to the control group. In conclusion, our study identifies a potential target for the treatment of late-stage ALI by promoting resolution througheffectorTreg-mediated suppression of inflammation.
适应性免疫反应可能在肺损伤的解决中发挥重要作用。尽管调节性 T 细胞 (regulatory T-cells，Tregs) 参与促进肺损伤的消退，但在损伤部位增强 Treg 数量和活性的治疗策略有待进一步探索。在目前的研究中，使用 triciribin (TCBN) 抑制 Akt，给予脂多糖 (LPS) 后 48 小时增加 Tregs 促进急性肺损伤 (ALI) 的消退。TCBN 治疗通过减少与 CD4 +/FoxP3 +/CD103 + 和 CTLA4 + 效应 Tregs 数量增加相关的肺水肿和中性粒细胞活性，增强了第 7 天 LPS 诱导的 ALI 的消退。在受伤的肺部而不是脾脏。用两种 Akt 抑制剂 (TCBN 和 EL-4) 处理 MK-2206 T 淋巴细胞 72 小时可导致 FoxP3 表达增加。另一方面，Treg 特异性 PTEN 基因敲除 (PTENTreg KO) 小鼠在其 Tregs 中具有更高的 Akt 活性，表现出对 ALI 消退的显著损伤, 与对照组相比，与 CD4 +/FoxP3 +/CD103 + 和 CTLA4 + effectorTregs 数量减少相关的水肿和中性粒细胞活性增加。总之，我们的研究通过 effectortreg 介导的炎症抑制促进消退，确定了治疗晚期 ALI 的潜在靶点。
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.