as-605240 and Acute-Lung-Injury

Mechanical ventilation (MV) used in patients with acute lung injury (ALI) induces lung inflammation and causes fibroblast proliferation and excessive collagen deposition-a process termed epithelial-mesenchymal transition (EMT). Phosphoinositide 3-kinase-γ (PI3K-γ) is crucial in modulating EMT during the reparative phase of ALI; however, the mechanisms regulating the interactions among MV, EMT, and PI3K-γ remain unclear. We hypothesized that MV with or without bleomycin treatment would increase EMT through the PI3K-γ pathway. C57BL/6 mice, either wild-type or PI3K-γ-deficient, were exposed to 6 or 30 mL/kg MV for 5 h after receiving 5 mg/kg AS605240 intraperitoneally 5 days after bleomycin administration. We found that, after bleomycin exposure in wild-type mice, high-tidal-volume MV induced substantial increases in inflammatory cytokine production, oxidative loads, Masson's trichrome staining level, positive staining of α-smooth muscle actin, PI3K-γ expression, and bronchial epithelial apoptosis (

Topics: Acute Lung Injury; Animals; Bleomycin; Epithelial-Mesenchymal Transition; Lung; Mice; Mice, Inbred C57BL; Phosphatidylinositol 3-Kinase; Phosphatidylinositol 3-Kinases

Acute lung injury (ALI) is a devastating disorder of the lung by various causes and its cardinal features are tissue inflammation, pulmonary edema, low lung compliance, and widespread capillary leakage. Among phosphoinositide 3-kinases (PI3Ks), PI3K-γ isoform has been shown to play an important role in a number of immune/inflammatory responses.. We investigated the role of PI3K-γ and its molecular basis in lipopolysaccharide (LPS)-induced ALI using a selective inhibitor for PI3K-γ, AS 605240, and LPS-treated C57BL/6 mice.. Treatment of mice with LPS showed an increase of lung inflammation and vascular leakage. Production of reactive oxygen species (ROS), interleukin (IL)-1β, tumor necrosis factor-α, and IL-4, adhesion molecule, and vascular endothelial growth factor (VEGF) was also increased. Administration of AS 605240 to LPS-treated mice markedly reduced the pathophysiological features of ALI and the increased production of ROS, cytokines, adhesion molecule, and VEGF in the lung. Our results also showed that treatment of mice with LPS activates nuclear factor-κB (NF-κB) and degradation of inhibitory κBα (IκBα) through PI3K-γ. Additionally, infiltration of dendritic cells (DCs) and expression of toll-like receptor 4 (TLR4) were significantly increased in the lung of LPS-treated mice, and inhibition of PI3K-γ reduced the infiltration of DCs and TLR4 expression in the lung.. These results indicate that PI3K-γ is critically involved in LPS-induced ALI by regulating IκBα/NF-κB pathway and innate immune responses. Based on our data, we suggest that PI3K-γ isoform is a promising target for the treatment of ALI.

Topics: Acute Lung Injury; Animals; Cell Nucleus; Class Ib Phosphatidylinositol 3-Kinase; Cytokines; Dendritic Cells; Enzyme Activation; Female; I-kappa B Proteins; Immunity, Innate; Inflammation Mediators; Intercellular Adhesion Molecule-1; Lipopolysaccharides; Mice; Mice, Inbred C57BL; NF-kappa B; NF-KappaB Inhibitor alpha; Peroxidase; Phosphoinositide-3 Kinase Inhibitors; Protein Transport; Quinoxalines; Reactive Oxygen Species; Signal Transduction; Thiazolidinediones; Toll-Like Receptor 4; Vascular Endothelial Growth Factor A

Phosphoinositide 3-kinase gamma(PI3Kgamma) is a critical mediator of directional cell movement. Here, we sought to characterise the role of PI3Kgamma in mediating the different steps of polymorphonuclear leukocyte (PMN) trafficking in the lung. In a murine model of lipopolysaccharide (LPS)-induced lung injury, PMN migration into the different lung compartments was determined in PI3Kgamma gene-deficient (PI3Kgamma(-/-)) and wild-type mice. Bone marrow chimeras were created to characterise the role of PI3Kgamma on haematopoietic versus nonhaematopoietic cells. A small-molecule PI3Kgamma inhibitor was tested in vitro and in vivo. PMN adhesion to the pulmonary endothelium and transendothelial migration into the lung interstitium was enhanced in PI3Kgamma(-/-) mice. However, transepithelial migration into the alveolar space was reduced in these mice. When irradiated PI3Kgamma(-/-) mice were reconstituted with bone marrow from wild-type mice, migratory activity into the alveolar space was restored partially. A small-molecule PI3Kgamma inhibitor reduced chemokine-induced PMN migration in vitro when PMNs or epithelial cells, but not when endothelial cells, were treated. The inhibitor also reduced LPS-induced PMN migration in vivo. We conclude that PI3Kgamma is required for transepithelial but not for transendothelial migration in LPS-induced lung injury. Inhibition of PI3Kgamma activity may be effective at curbing excessive PMN infiltration in lung injury.

Topics: Acute Lung Injury; Analysis of Variance; Animals; Bronchoalveolar Lavage Fluid; Cell Movement; Chimera; Class Ib Phosphatidylinositol 3-Kinase; Disease Models, Animal; Flow Cytometry; Humans; Intracellular Signaling Peptides and Proteins; Isoenzymes; Lipopolysaccharides; Lung; Male; Membrane Proteins; Mice; Neutrophils; Phosphatidylinositol 3-Kinases; Quinoxalines; Thiazolidinediones