su-1498 and Asthma

Asthma is a chronic respiratory disease characterized by reversible airway obstruction with persistent airway inflammation and airway remodeling. Features of airway remodeling include increased airway smooth muscle (ASM) mass. A disintegrin and metalloproteinase (ADAM)-33 has been identified as playing a role in the pathophysiology of asthma. ADAM-33 is expressed in ASM cells and is suggested to play a role in the function of these cells. However, the regulation of ADAM-33 is not fully understood. Vascular endothelial growth factor (VEGF) has been implicated in inflammatory and airway blood vessel remodeling in asthmatics. Although VEGF was initially thought of as an endothelial-specific growth factor, recent reports have found that VEGF can promote proliferation of other cell types, including ASM cells. To investigate the precise mechanism of VEGF's effect on ASM cell proliferation, we tested the expression of ADAM-33, phospho-extracellularsignal-regulated kinase 1/2 (ERK1/2), and phospho-Akt in VEGF-stimulated ASM cells. We found that VEGF up-regulates ADAM-33 mRNA and protein levels in a dose- and time-dependent manner as well as phosphorylation of ERK1/2 and Akt. We also found that VEGF-induced ASM cell proliferation is inhibited by both ADAM-33 knockdown and a selective VEGF receptor 2 (VEGFR2) inhibitor (SU1498). Furthermore, VEGF-induced ADAM-33 expression and ASM cell proliferation were suppressed by inhibiting ERK1/2 activity, but not by inhibiting Akt activity. Collectively, our findings suggest that VEGF enhances ADAM-33 expression and ASM cell proliferation by activating the VEGFR2/ERK1/2 signaling pathway, which might be involved in the pathogenesis of airway remodeling. Further elucidation of the mechanisms underlying these observations might help develop therapeutic strategies for airway diseases associated with smooth muscle hyperplasia such as asthma.

Topics: ADAM Proteins; Asthma; Butadienes; Cell Proliferation; Cinnamates; Extracellular Signal-Regulated MAP Kinases; G1 Phase Cell Cycle Checkpoints; Humans; Lung; Myocytes, Smooth Muscle; Nitriles; Phosphorylation; Proto-Oncogene Proteins c-akt; RNA, Messenger; RNA, Small Interfering; Transfection; Up-Regulation; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-2

Vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) are mediators of airway inflammation and remodeling in asthma.. This study investigates a potential relationship between VEGF and MMP-9, and the mechanisms by which VEGF signaling regulates MMP-9 expression in asthma.. We evaluated whether levels of VEGF correlated with levels of MMP-9 in the sputum of asthma patients, and the effect of VEGF receptor inhibitors on MMP-9 expression in murine model of asthma.. We have found that levels of VEGF and MMP-9 are significantly higher in the sputum of patients with asthma than in healthy control subjects, and a significant correlation is found between the levels of VEGF and MMP-9. This study with the ovalbumin-induced model of asthma revealed the following typical pathophysiologic features of asthma in the lungs: increased numbers of inflammatory cells of the airways, airway hyperresponsiveness, increased vascular permeability, and increased levels of MMP-9 and VEGF. Administration of VEGF receptor inhibitors reduced the pathophysiologic signs of asthma and decreased the increased expression of MMP-9 after ovalbumin inhalation.. These results indicate that there is a close relationship between VEGF and MMP-9 expression and that inhibition of VEGF receptor down-regulates the expression of MMP-9. These findings suggest that VEGF signaling regulates MMP-9 expression and plays a critical role in initiation and maintenance of asthma.

Topics: Asthma; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Cinnamates; Down-Regulation; Humans; Immunohistochemistry; Indoles; Interleukin-13; Interleukin-4; Interleukin-5; Matrix Metalloproteinase 9; Ovalbumin; Sputum; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-2

Bronchial asthma is characterized by inflammation of the airways, which is usually accompanied by increased vascular permeability, resulting in plasma exudation. Vascular endothelial growth factor (VEGF) has been implicated in contributing to asthmatic tissue edema through its effect on vascular permeability. Many cellular responses of VEGF are regulated by the lipid products of phosphoinositide 3-kinase (PI3K). However, the effect of PI3K catalytic subunit p110delta on VEGF-mediated signaling is unknown. Recently, an isoform-specific small molecule inhibitor, IC87114, which is selective for p110delta catalytic activity, has been identified.. We have sought to investigate the role of PI3K-delta, more specifically in the increase of vascular permeability.. Female BALB/c mice were sensitized and challenged with ovalbumin. We have investigated the effect of IC87114 on airway inflammation, T(H)2 cytokines expression, airway hyperresponsiveness, plasma extravasation, hypoxia-inducible factor 1alpha expression, and VEGF expression in a murine model of asthma.. Our current study has revealed that IC87114 reduces antigen-induced airway infiltration of inflammatory cells, secretion of T(H)2 cytokines in lungs, airway hyperresponsiveness, and vascular permeability. Moreover, we have found that inhibition of p110delta reduces ovalbumin-induced upregulation of VEGF level.. These results suggest that PI3K-delta inhibitor attenuates antigen-induced airway inflammation and hyperresponsiveness by preventing vascular leakage in mice.. These findings provide a crucial molecular mechanism for the potential role of PI3K-delta in asthma and other airway inflammatory disorders.

Topics: Adenine; Animals; Asthma; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Capillary Permeability; Cinnamates; Class I Phosphatidylinositol 3-Kinases; Cytokines; Disease Models, Animal; Enzyme Inhibitors; Female; Hypoxia-Inducible Factor 1, alpha Subunit; Indoles; Leukocyte Count; Lung; Mice; Mice, Inbred BALB C; Ovalbumin; Phosphoinositide-3 Kinase Inhibitors; Pneumonia; Quinazolines; Receptors, Vascular Endothelial Growth Factor; Vascular Endothelial Growth Factor A