WNK4-SPAK modulates lipopolysaccharide-induced macrophage activation.
- 作者列表："Hung CM","Peng CK","Yang SS","Shui HA","Huang KL
:Dysregulation of alveolar macrophage activation has been recognized as the major mechanism in the pathogenesis of acute lung injury. The aim of the present study was to investigate the role of NKCC1 regulating mechanism in modulating macrophage activation. Knockout (SPAK-/- and WNK4-/-) and knockin (WNK4D561A/+) mice were used in this study. LPS induced expression of p-NKCC1 and activation of NFκB in the primary culture of alveolar macrophages. WNK4 or SPAK knockout suppressed p-NKCC1 expression and inflammation cascade activation, whereas WNK4 knockin enhanced these responses. Intrapulmonary administration of LPS induced in vivo expression and phosphorylation of NKCC1 in alveolar inflammation cells and caused a shift in the cell population from macrophage to neutrophil predominance. WNK4 or SPAK knockout attenuated the LPS-induced alveolar cell-population shifting, macrophage NKCC1 phosphorylation, and acute lung injury, whereas WNK4 knockin augmented the inflammatory response. In summary, our results demonstrated the presence of NKCC1 in alveolar macrophage, which is inducible by lipopolysaccharide. Our results also showed showed that the WNK4-SPAK-NKCC1 cascade plays an important role in modulating macrophage activation to regulate LPS-induced lung inflammation and lung injury.
肺泡巨噬细胞活化失调已被认为是急性肺损伤发病的主要机制。本研究的目的是探讨 NKCC1 调节机制在调节巨噬细胞活化中的作用。本研究采用基因敲除 (SPAK-/-和 WNK4-/-) 和基因敲除 (WNK4D561A/+) 小鼠。LPS 诱导肺泡巨噬细胞原代培养 p-NKCC1 表达及 nf κ b 活化WNK4 或 SPAK 敲除抑制 p-NKCC1 表达和炎症级联激活，而 WNK4 敲除增强了这些反应。肺内给予 LPS 诱导肺泡炎症细胞中 NKCC1 的体内表达和磷酸化，并引起细胞群从巨噬细胞向中性粒细胞为主的转变。WNK4 或 SPAK 敲除可减弱 LPS 诱导的肺泡细胞群转移、巨噬细胞 NKCC1 磷酸化和急性肺损伤，而 WNK4 敲除可增强炎症反应。总之，我们的结果证明了肺泡巨噬细胞中 NKCC1 的存在，它是由脂多糖诱导的。我们的研究结果还表明，WNK4-SPAK-NKCC1 级联反应在调节巨噬细胞活化以调节 LPS 诱导的肺部炎症和肺损伤中起重要作用。
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.