Excessive airway obstruction is the cause of symptoms and abnormal lung function in asthma.As airway smooth muscle (ASM) is the effecter controlling airway calibre, it is suspected that dysfunction of ASM contributes to the pathophysiology of asthma. However, the precise role of ASM in the series of events leading to asthmatic symptoms is not clear. It is not certain whether, in asthma, there is a change in the intrinsic properties of ASM, a change in the structure and mechanical properties of the noncontractile components of the airway wall, or a change in the interdependence of the airway wall with the surrounding lung parenchyma. All these potential changes could result from acute or chronic airway inflammation and associated tissue repair and remodelling.Anti-inflammatory therapy, however, does not ''cure'' asthma, and airway hyperresponsiveness can persist in asthmatics, even in the absence of airway inflammation. This is perhaps because the therapy does not directly address a fundamental abnormality of asthma, that of exaggerated airway narrowing due to excessive shortening of ASM.In the present study, a central role for airway smooth muscle in the pathogenesis of airway hyperresponsiveness in asthma is explored.

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Effective treatment for managing myocardial infarction (MI) remains an urgent, unmet clinical need. Formyl peptide receptors (FPR) regulate inflammation, a major contributing mechanism to cardiac injury following MI. Here we demonstrate that FPR1/FPR2-biased agonism may represent a novel therapeutic strategy for the treatment of MI. The small-molecule FPR1/FPR2 agonist, Compound 17b (Cmpd17b), exhibits a distinct signalling fingerprint to the conventional FPR1/FPR2 agonist, Compound-43 (Cmpd43). In Chinese hamster ovary (CHO) cells stably transfected with human FPR1 or FPR2, Compd17b is biased away from potentially detrimental FPR1/2-mediated calcium mobilization, but retains the pro-survival signalling, ERK1/2 and Akt phosphorylation, relative to Compd43. The pathological importance of the biased agonism of Cmpd17b is demonstrable as superior cardioprotection in both in vitro (cardiomyocytes and cardiofibroblasts) and MI injury in mice in vivo. These findings reveal new insights for development of small molecule FPR agonists with an improved cardioprotective profile for treating MI.

Background:The refractive index (RI) of cellular material provides fundamental biophysical information about the composition and organizational structure of cells. Efforts to describe the refractive properties of cells have been significantly impeded by the experimental difficulties encountered in measuring viable cell RI. In this report we describe a procedure for the application of quantitative phase microscopy in conjunction with confocal microscopy to measure the RI of a cultured muscle cell specimen. Methods: The experimental strategy involved calculation of cell thickness by using confocal optical sectioning procedures, construction of a phase map of the same cell using quantitative phase microscopy, and selection of cellular regions of interest to solve for the cell RI. Results: Mean cell thickness and phase values for six cell regions (five cytoplasmic and one nuclear) were deter-

Granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulates hemopoiesis and effector functions of granulocytes and macrophages and is involved in pulmonary surfactant homeostasis. We investigated whether GM-CSF therapy improved clinically diagnosed severe sepsis and respiratory dysfunction in critically ill patients. This randomized, double-blind, placebo-controlled phase II study added low-dose (3 mcg/kg) intravenous recombinant human GM-CSF daily for 5 days to conventional therapy in 10 patients, with a further eight patients receiving placebo. GM-CSF-treated patients showed improvement in Pa(O(2))/FI(O(2)) over 5 days (p = 0.02) and increased peripheral blood neutrophils (p = 0.08), whereas alveolar neutrophils decreased (p = 0.02). GM-CSF therapy was not associated with decreased 30-day survival or with increased acute respiratory distress syndrome or extrapulmonary organ dysfunction. GM-CSF therapy was associated with increased blood granulocyte superoxide production and restoration or preservation of blood and alveolar leukocyte phagocytic function. We conclude that low-dose GM-CSF was associated with improved gas exchange without pulmonary neutrophil infiltration, despite functional activation of both circulating neutrophils and pulmonary phagocytes. In addition, GM-CSF therapy was not associated with worsened acute respiratory distress syndrome or the multiple organ dysfunction syndrome, suggesting a homeostatic role for GM-CSF in sepsis-related pulmonary dysfunction.

We have previously shown that glucocorticoids inhibit mitogen-stimulated proliferation of human cultured airway smooth muscle (ASM) cells. The present study analyzed the effect of glucocorticoids on key regulatory pathways leading to passage of cells through the restriction point of the cell cycle, including those mediated by extracellular-regulated kinases (ERK) 1 and 2; the ERK upstream regulator MAPK kinase (MEK1); cyclin D1 levels; and levels and phosphorylation of retinoblastoma protein (pRb). Fluticasone propionate, a new inhaled glucocorticoid, was at least 10-fold more potent than dexamethasone in inhibiting thrombin-stimulated DNA synthesis and increases in cell number. Thrombin-stimulated increases in the levels and hyperphosphorylation of pRb were inhibited by glucocorticoids, which also reduced thrombin-stimulated cyclin D1 protein and messenger RNA (mRNA) levels. PD98059 (10 microM), an inhibitor of MEK1 activation, markedly attenuated thrombin stimulation of ERK activity and phosphorylation, DNA synthesis, and cyclin D1 levels. However, glucocorticoids had no effect on ERK activity or phosphorylation at 5 min, 2 h, or 12 h after addition of thrombin. In conclusion, glucocorticoid-induced reduction of cyclin D1 mRNA and protein levels, and of pRb phosphorylation, is sufficient to account for inhibition of ASM proliferation. Furthermore, these inhibitory effects of glucocorticoids on cyclin D1 and pRb occur on a component of the mitogen signaling cascade that is either downstream of or parallel to the ERK pathway.

1 P2-Adrenoceptor agonists may exacerbate asthma by reducing the release of the anti-proliferative and anti-inflammatory molecule, heparin from mast cells in the airway. In this study, the direct effects of the clinically used bronchodilator, salbutamol, on the proliferation of airway smooth muscle cells grown in culture and stimulated with a range of mitogens have been examined.2 In mitogen-stimulated cells, salbutamol (0.1-I00 nM) inhibited [3H]-thymidine incorporation in a concentration-dependent manner. Salbutamol (100 nM) pretreatment reduced the mitogenic responses to thrombin (0.3 u ml-1), epidermal growth factor (EGF) (300 pM) and U46619 (100 nM) by 61.7 ± 6.1%, 46.9 ± 13.9% and 57.6 ± 12.7%, respectively. However, salbutamol pretreatment did not appear to reduce the small mitogenic response to endothelin-1. 3 Increases in [3H]-leucine incorporation in thrombin (0.3 u ml-')-stimulated cells were reduced by salbutamol (100 nM) by 27.7 ± 2.8%. Similarly, thrombin (0.3 u ml`)-stimulated increases in cell number were also inhibited by salbutamol (100 nM) pretreatment. Thus, the effect of salbutamol in decreasing thrombin-induced [3H]-leucine incorporation may, at least in part, be explained by inhibition of cell proliferation. 4 The inhibition of cell proliferation by salbutamol was prevented by pretreatment with either the non-selective P-adrenoceptor antagonist, propranolol (0.3 JAM) or the selective P2-adrenoceptor antagonist, ICI 118551 (50 nM).5 These results indicate that salbutamol, through activation of a P2-adrenoceptor, has a direct inhibitory effect on proliferation elicited by the mitogens thrombin, EGF, and U46619. Thus, it seems likely that this direct inhibitory action of P2-adrenoceptor agonists would override any indirect action to accelerate airway smooth muscle proliferation. These observations lead us to suggest that R2-adrenoceptor agonists exacerbate asthma by mechanisms unrelated to airway smooth muscle proliferation.

Early metastasis leads to poor prognosis of lung cancer patients, whose 5-year survival rate is only 15%. We could recently show that the Ca 2+ sensitive K + channel K Ca 3.1 promotes aggressive behavior of non-small cell lung cancer (NSCLC) cells and that it can serve as a prognostic marker in NSCLC. Since NSCLC patients die of metastases, we investigated whether K Ca 3.1 channels contribute to poor patient prognosis by regulating distinct steps of the metastatic cascade.