scholarly journals Deletion of P2X7 attenuates hyperoxia-induced acute lung injury via inflammasome suppression

2016 ◽  
Vol 310 (6) ◽  
pp. L572-L581 ◽  
Author(s):  
Lakshmi Galam ◽  
Ashna Rajan ◽  
Athena Failla ◽  
Ramani Soundararajan ◽  
Richard F. Lockey ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Alveolar Macrophages ◽  
P2x7 Receptor ◽  
Protective Factor ◽  
Receptor Activation ◽  
Alveolar Epithelial Cells ◽  
Lung Edema ◽  
Inflammasome Activation ◽  
Type Ii

Increasing evidence shows that hyperoxia is a serious complication of oxygen therapy in acutely ill patients that causes excessive production of free radicals leading to hyperoxia-induced acute lung injury (HALI). Our previous studies have shown that P2X7 receptor activation is required for inflammasome activation during HALI. However, the role of P2X7 in HALI is unclear. The main aim of this study was to determine the effect of P2X7 receptor gene deletion on HALI. Wild-type (WT) and P2X7 knockout (P2X7 KO) mice were exposed to 100% O2for 72 h. P2X7 KO mice treated with hyperoxia had enhanced survival in 100% O2compared with the WT mice. Hyperoxia-induced recruitment of inflammatory cells and elevation of IL-1β, TNF-α, monocyte chemoattractant protein-1, and IL-6 levels were attenuated in P2X7 KO mice. P2X7 deletion decreased lung edema and alveolar protein content, which are associated with enhanced alveolar fluid clearance. In addition, activation of the inflammasome was suppressed in P2X7-deficient alveolar macrophages and was associated with suppression of IL-1β release. Furthermore, P2X7-deficient alveolar macrophage in type II alveolar epithelial cells (AECs) coculture model abolished protein permeability across mouse type II AEC monolayers. Deletion of P2X7 does not lead to a decrease in epithelial sodium channel expression in cocultures of alveolar macrophages and type II AECs. Taken together, these findings show that deletion of P2X7 is a protective factor and therapeutic target for the amelioration of hyperoxia-induced lung injury.

scholarly journals Inhibition of GGPPS1 attenuated LPS-induced acute lung injury and was associated with NLRP3 inflammasome suppression

2019 ◽  
Vol 316 (3) ◽  
pp. L567-L577 ◽  
Author(s):  
Wu-jian Xu ◽  
Xiao-xia Wang ◽  
Jia-jia Jin ◽  
Qian Zou ◽  
Lin Wu ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Epithelial Cells ◽  
Lung Injury ◽  
Nlrp3 Inflammasome ◽  
Mevalonate Pathway ◽  
Alveolar Epithelial Cells ◽  
Inflammasome Activation ◽  
Wild Type ◽  
Alveolar Epithelial ◽  
Geranylgeranyl Pyrophosphate Synthase

Inhibition of the mevalonate pathway using statins has been shown to be beneficial in the treatment of acute lung injury (ALI). Here, we investigated whether partial inhibition of this pathway by targeting geranylgeranyl pyrophosphate synthase large subunit 1 (GGPPS1), a catalase downstream of the mevalonate pathway, was effective at treating lung inflammation in ALI. Lipopolysaccharide (LPS) was intratracheally instilled to induce ALI in lung-specific GGPPS1-knockout and wild-type mice. Expression of GGPPS1 in lung tissues and alveolar epithelial cells was examined. The severity of lung injury and inflammation was determined in lung-specific GGPPS1 knockout and wild-type mice by measuring alveolar exudate, neutrophil infiltration, lung injury, and cell death. Change in global gene expression in response to GGPPS1 depletion was measured using mRNA microarray and verified in vivo and in vitro. We found that GGPPS1 levels increased significantly in lung tissues and alveolar epithelial cells in LPS-induced ALI mice. Compared with wild-type and simvastatin treated mice, the specific deletion of pulmonary GGPPS1 attenuated the severity of lung injury by inhibiting apoptosis of AECs. Furthermore, deletion of GGPPS1 inhibited LPS-induced inflammasome activation, in terms of IL-1β release and pyroptosis, by downregulating NLRP3 expression. Finally, downregulation of GGPPS1 reduced the membrane expression of Ras-related protein Rab10 and Toll-like receptor 4 (TLR4) and inhibited the phosphonation of IκB. This effect might be attributed to the downregulation of GGPP levels. Our results suggested that inhibition of pulmonary GGPPS1 attenuated LPS-induced ALI predominantly by suppressing the NLRP3 inflammasome through Rab10-mediated TLR4 replenishment.

scholarly journals Surface expression of CD74 by type II alveolar epithelial cells: a potential mechanism for macrophage migration inhibitory factor-induced epithelial repair

2009 ◽  
Vol 296 (3) ◽  
pp. L442-L452 ◽  
Author(s):  
Leigh M. Marsh ◽  
Lidija Cakarova ◽  
Grazyna Kwapiszewska ◽  
Werner von Wulffen ◽  
Susanne Herold ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Lung Injury ◽  
Macrophage Migration Inhibitory Factor ◽  
Alveolar Epithelial Cells ◽  
Macrophage Migration ◽  
Type Ii ◽  
Alveolar Epithelial ◽  
Stimulation Of

Macrophage migration inhibitory factor (MIF) is a pleiotropic proinflammatory cytokine involved in acute lung injury and other processes such as wound repair and tumor growth. MIF exerts pro-proliferative effects on a variety of cell types including monocytes/macrophages, B cells, and gastric epithelial cell lines through binding to the major histocompatibility complex type II-associated invariant chain, CD74. In acute lung injury, inflammatory damage of the alveolar epithelium leads to loss of type I alveolar epithelial cells (AEC-I), which are replaced by proliferation and differentiation of type II alveolar epithelial cells (AEC-II). In this study we have investigated the potential of MIF to contribute to alveolar repair by stimulating alveolar epithelial cell proliferation. We show that murine AEC-II, but not AEC-I, express high surface levels of CD74 in vivo. Culture of AEC-II in vitro resulted in decreased mRNA levels for CD74 and loss of surface CD74 expression, which correlated with a transition of AEC-II to an AEC-I-like phenotype. MIF stimulation of AEC-II induced rapid and prolonged phosphorylation of ERK1/2 and Akt, increased expression of cyclins D1 and E, as well as AEC-II proliferation. Corresponding MIF signaling and enhanced thymidine incorporation was observed after MIF stimulation of MLE-12 cells transfected to overexpress CD74. In contrast, MIF did not induce MAPK activation, gene transcription, or increased proliferation in differentiated AEC-I-like cells that lack CD74. These data suggest a previously unidentified role of MIF-CD74 interaction by inducing proliferation of AEC-II, which may contribute to alveolar repair.

scholarly journals Lats2-Underexpressing Bone Marrow-Derived Mesenchymal Stem Cells Ameliorate LPS-Induced Acute Lung Injury in Mice

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Liang Dong ◽  
Lang Li
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Mesenchymal Stem Cells ◽  
Acute Lung Injury ◽  
Lung Injury ◽  
Lung Inflammation ◽  
Alveolar Epithelial Cells ◽  
Lung Edema ◽  
Alveolar Epithelial

The pathophysiology of the acute lung injury (ALI) is characterized by the damage of alveolar epithelial cells, which can be repaired by exogenous bone marrow-derived mesenchymal stem cells (BMSCs). However, the migration and differentiation abilities of BMSCs are not sufficient for the purpose, and a new approach that could strengthen the repair effects of BMSCs in ALI still needs to be clarified. We have previously proved that in vitro large tumor suppressor kinase 2- (Lats2-) underexpressing BMSCs may enhance their tissue repair effects in ALI; thus, in the present study, we tried to explore whether Lats2-underexpressing BMSCs could rescue lipopolysaccharide- (LPS-) induced ALI in vivo. BMSCs from C57BL/6 mice transfected with Lats2-interfering lentivirus vector or lentivirus blank controls were transplanted intratracheally into LPS-induced ALI mice. The retention and differentiation of BMSCs in the lung were evaluated by in vivo imaging, immunofluorescence staining, and Western blotting. The lung edema and permeability were assessed by lung wet weight/body weight ratio (LWW/BW) and measurements of proteins in bronchoalveolar lavage fluid (BALF) using ELISA. Acute lung inflammation was measured by the cytokines in the lung homogenate and BALF using RT-qPCR and ELISA, respectively. Lung injury was evaluated by HE staining and lung injury scoring. Pulmonary fibrosis was evaluated by Picrosirius red staining, immunohistochemistry for α-SMA and TGF-β1, and hydroxyproline assay and RT-qPCR for Col1α1 and Col3α1. Lats2-mediated inhibition of the Hippo pathway increased the retention of BMSCs and their differentiation toward type II alveolar epithelial cells in the lung. Furthermore, Lats2-underexpressing BMSCs improved lung edema, permeability of the lung epithelium, and lung inflammation. Finally, Lats2-underexpressing BMSCs alleviated lung injury and early pulmonary fibrosis. Our studies suggest that underexpression of Lats2 could further enhance the repair effects of BMSCs against epithelial impair and the therapeutic potential of BMSCs in ALI mice.

Inhaled nitric oxide reduces lung edema during fluid resuscitation in ovine acute lung injury

2003 ◽  
Vol 29 (10) ◽  
pp. 1790-1797 ◽  
Author(s):  
Henning D. Stubbe ◽  
Martin Westphal ◽  
Hugo Van Aken ◽  
Christoph Hucklenbruch ◽  
Stefan Lauer ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Acute Lung Injury ◽  
Lung Injury ◽  
Fluid Resuscitation ◽  
Inhaled Nitric Oxide ◽  
Lung Edema
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