gw9662 and Pneumonia

The present study aims to reveal the molecular mechanism of peroxisome proliferator-activated receptor γ (PPARγ) on sepsis-induced acute lung injury (ALI). To do that, the rat injury model was established using cecal ligation and perforation (CLP) method, followed by different treatments, and the rats were divided into Sham group, CLP group, CLP + rosiglitazone (PPARγ agonist) group, CLP + GW9662 (PPARγ inhibitor) group, CLP + bpV (phosphatase and tensin homolog (PTEN) inhibitor) group, CLP + GW9662 + bpV group. Compared with Sham group, the mRNA and protein expression levels of PPARγ were down-regulated, the inflammation levels were elevated, and the apoptosis was increased in CLP group. After treatment with rosiglitazone, the protein expression level of PPARγ was significantly up-regulated, the phosphorylation level of PTEN/β-catenin pathway was decreased, the PTEN/β-catenin pathway was inhibited, the lung injury, inflammation and apoptosis were reduced. The opposite effect was observed after treatment with GW9662. Besides, bpV inhibited PTEN/β-catenin pathway, and relieved the lung tissue injury. The overexpression of PPARγ reduced inflammatory response and inhibited apoptosis in sepsis-induced ALI. Furthermore, PPARγ relieved the sepsis-induced ALI by inhibiting the PTEN/β-catenin pathway.

Topics: Acute Lung Injury; Anilides; Animals; Apoptosis; beta Catenin; Disease Models, Animal; Lung; Male; Phosphorylation; Pneumonia; PPAR gamma; PTEN Phosphohydrolase; Pulmonary Edema; Rats, Sprague-Dawley; Rosiglitazone; Sepsis; Signal Transduction

Changes in macrophage phenotype have been implicated in apoptotic cell-mediated immune modulation via induction of peroxisome proliferator-activated receptor-γ (PPARγ). In this study, we characterized PPARγ induction by apoptotic cell instillation over the course of bleomycin-induced lung injury in C57BL/6 mice. Next, the role of PPARγ activation in resolving lung inflammation and fibrosis was investigated. Our data demonstrate that apoptotic cell instillation after bleomycin results in immediate and prolonged enhancement of PPARγ mRNA and protein in alveolar macrophages and lung. Moreover, PPARγ activity and expression of its target molecules, including CD36, macrophage mannose receptor, and arginase 1, were persistently enhanced following apoptotic cell instillation. Coadministration of the PPARγ antagonist, GW9662, reversed the enhanced efferocytosis, and the reduced proinflammatory cytokine expression, neutrophil recruitment, myeloperoxidase activity, hydroxyproline contents, and fibrosis markers, including type 1 collagen α2, fibronectin and α-smooth muscle actin (α-SMA), in the lung by apoptotic cell instillation. In addition, inhibition of PPARγ activity reversed the expression of transforming growth factor-β (TGF-β), interleukin (IL)-10, and hepatocyte growth factor (HGF). These findings indicate that one-time apoptotic cell instillation contributes to anti-inflammatory and antifibrotic responses via upregulation of PPARγ expression and subsequent activation, leading to regulation of efferocytosis and production of proresolving cytokines.

Topics: Anilides; Animals; Apoptosis; Bleomycin; Cytokines; HeLa Cells; Humans; Jurkat Cells; Lung; Male; Mice; Pneumonia; PPAR gamma; Pulmonary Fibrosis

Preliminary studies show that intranasal (i.n.) administration of BCG in mice induces M1 activation of alveolar macrophages (M∅) that increase TNF-α production and cyclooxygenase-2 (COX-2) expression but reduce constitutive peroxisome proliferator-activated receptor gamma (PPARγ) expression. However, COX-2 is catalytically inactive for prostaglandin E(2) release, unlike COX-2 that is active in M1 activation in vitro by BCG. In this study, we determined the role of PPARγ for BCG-induced M1 activation in vivo and in vitro. We found that treatment of mice with GW9662, a PPARγ antagonist, prior to i.n. BCG, partially restored PPARγ expression, and decreased TNF-α production and COX-2 expression. But COX-2 was still inactive. The decreased effects on TNF-α and COX-2 were also observed when alveolar M∅ were treated in vitro with GW9662/BCG, but COX-2 was still active. Our results indicate that PPARγ upregulates M1 activation of alveolar M∅, but inactive COX-2 formation is independent of PPARγ in mycobacterial pulmonary inflammation.

Topics: Anilides; Animals; BCG Vaccine; Bronchoalveolar Lavage Fluid; Cyclooxygenase 2; Enzyme Activation; Female; Macrophage Activation; Macrophages, Alveolar; Mice; Mice, Inbred C57BL; Pneumonia; PPAR gamma; Tumor Necrosis Factor-alpha

Microparticles (MP) are phospholipid vesicles shed by cells upon activation or apoptosis. Monocyte-derived MP upregulate the synthesis of proinflammatory mediators by lung epithelial cells; the molecular bases of such activity are unknown. Peroxisome proliferator-activated receptors (PPAR) have been demonstrated to be involved in the modulation of nuclear factor (NF)-κB transcriptional activity and inflammation. We investigated whether the upregulation of the synthesis of proinflammatory cytokines by human lung epithelial cells induced by monocyte/macrophage-derived MP involves NF-κB activation and is modulated by PPAR-γ. MP were generated by stimulation of human monocytes/macrophages with the calcium ionophore, A23187. MP were incubated with human lung epithelial cells. NF-κB translocation was assessed by electrophoretic mobility shift assay. Interleukin (IL)-8 and monocyte chemotactic protein (MCP)-1 synthesis was assessed by ELISA and RT-PCR. Stimulation of A549 alveolar cells with monocyte/macrophage-derived MP caused an increase in NF-κB activation and IL-8 and MCP-1 synthesis that was inhibited by pre-incubation with the PPAR-γ agonists, rosiglitazone and 15-deoxy-Δ12,14-prostaglandin-J2. Parallel experiments with normal human bronchial epithelial cells largely confirmed the results. The effects of PPAR-γ agonists were reversed by the specific antagonist, GW9662. Upregulation of the synthesis of proinflammatory mediators by human lung epithelial cells induced by monocyte/macrophage-derived MP is mediated by NF-κB activation through a PPAR-γ dependent pathway.

Topics: Anilides; Bronchi; Calcimycin; Cell Line; Cell-Derived Microparticles; Cells, Cultured; Chemokine CCL2; Humans; Interleukin-8; Ionophores; Monocytes; NF-kappa B; Pneumonia; PPAR gamma; Prostaglandin D2; Rosiglitazone; Thiazolidinediones; Up-Regulation

The effect of rosiglitazone, a potent peroxisome proliferator-activated receptor gamma (PPAR-gamma) agonist, on pulmonary inflammation in endotoxemia was investigated.. Male Wistar rats were given either lipopolysaccharide (LPS, 6 mg/kg i.v.) or saline, pretreated with rosiglitazone (0.3 mg/kg i.v.) or its vehicle (dimethyl sulphoxide) 30 min before LPS. The selective PPAR-gamma antagonist GW9662 (0.3 mg/kg i.v.) was given 20 min before rosiglitazone. Wet/dry weight (W/D) ratio, myeloperoxidase (MPO) activity, malondialdehyde (MDA) as well as TNF-alpha and CINC-1 concentrations were measured in lung tissues 4 h after LPS injection. Expression of ICAM-1, NF-kappaB p65 and PPAR-gamma were also determined by immunohistochemistry or Western blot analysis.. Rosiglitazone pretreatment significantly attenuated the increases in W/D ratio, MPO activity and MDA levels, and reduced pulmonary overproduction of TNF-alpha and CINC-1 as well as expression of ICAM-1 following endotoxemia. Rosiglitazone also inhibited the nuclear localization of NF-kappaB and up-regulated the expression of PPAR-gamma protein. The specific PPAR-gamma antagonist GW9662 abolished the effect of rosiglitazone.. These findings suggest that PPAR-gamma agonists might be used as therapeutic agents in the therapy of inflammatory lung injury related to endotoxemia.

Topics: Anilides; Animals; Anti-Inflammatory Agents; Blotting, Western; Chemokine CXCL1; Chemokines, CXC; Endotoxemia; Immunohistochemistry; Intercellular Adhesion Molecule-1; Intercellular Signaling Peptides and Proteins; Lipid Peroxidation; Lung; Male; Malondialdehyde; Neutrophil Infiltration; NF-kappa B; Peroxidase; Pneumonia; PPAR gamma; Pulmonary Edema; Rats; Rats, Wistar; Rosiglitazone; Thiazolidinediones; Tumor Necrosis Factor-alpha