The transcription factor NF-B, a central regulator of immunity, is subject to regulation by redox changes. We now report that cysteine-179 of the inhibitory B kinase (IKK) ␤-subunit of the IKK signalosome is a central target for oxidative inactivation by means of S-glutathionylation. S-glutathionylation of IKK-␤ Cys-179 is reversed by glutaredoxin (GRX), which restores kinase activity.

The forced oscillation technique (FOT) is a powerful, integrative and translational tool permitting the experimental assessment of lung function in mice in a comprehensive, detailed, precise and reproducible manner. It provides measurements of respiratory system mechanics through the analysis of pressure and volume signals acquired in reaction to predefined, small amplitude, oscillatory airflow waveforms, which are typically applied at the subject's airway opening. The present protocol details the steps required to adequately execute forced oscillation measurements in mice using a computer-controlled piston ventilator (flexiVent; SCIREQ Inc, Montreal, Qc, Canada). The description is divided into four parts: preparatory steps, mechanical ventilation, lung function measurements, and data analysis. It also includes details of how to assess airway responsiveness to inhaled methacholine in anesthetized mice, a common application of this technique which also extends to other outcomes and various lung pathologies. Measurements obtained in naïve mice as well as from an oxidative-stress driven model of airway damage are presented to illustrate how this tool can contribute to a better characterization and understanding of studied physiological changes or disease models as well as to applications in new research areas.

The chronicity of bronchial asthma is attributed to persistent airway inflammation and to a variety of structural changes, or remodelling, that includes smooth muscle and goblet cell hyperplasia.To investigate the mechanisms of airway remodelling, the current authors used an established allergen (ovalbumin; OVA)-driven rodent model (the Brown Norway rat).Brown Norway rats were sensitised to OVA and challenged three times at 5-day intervals to evoke airway remodelling. The effects of an epidermal growth factor (EGF) receptor inhibitor, AG1478, and a cysteinyl leukotriene-1 receptor antagonist, montelukast, on epithelial and airway smooth muscle (ASM) cell proliferation in vivo in response to repeated OVA challenge were tested. Three challenges with leukotriene (LT)D 4 were given, to examine their effects on remodelling with and without AG1478 pretreatment.OVA challenges caused ASM hyperplasia, with an increase in mass, epithelial cell proliferation and goblet cell proliferation. AG1478 prevented the changes, as did montelukast. Multiple OVA challenges increased heparin-binding EGF-like growth factor but not EGF expression by airway epithelium. LTD 4 reproduced the changes in remodelling induced by OVA and this was blocked by AG1478.Allergen-induced airway epithelial and airway smooth muscle remodelling is mediated by cysteinyl leukotrienes via the cysteinyl leukotriene-1 receptor with downstream effects on the epidermal growth factor receptor axis.KEYWORDS: Allergy, inflammation, lung, signal transduction A sthmatic airways often show extensive and complex remodelling [1][2][3][4]. The growth of smooth muscle has the potential to have the most significant pathophysiological consequences through excessive airway narrowing and airway hyperresponsiveness [5,6]. Increase in airway smooth muscle (ASM) in the airways has been associated with the severity of asthma [3,7], and when present in excess in the large airways is associated with mortality [8]. It is known that hyperplasia of smooth muscle in animal models [9][10][11] and both hyperplasia and hypertrophy in airway specimens from human subjects [12,13] contribute to the increase in ASM mass. It has also been proposed that migration of subepithelial myofibroblasts may add to the tissue mass [7].The mechanism of the growth response of muscle is quite uncertain, although several descriptive studies of growth factor expression in human airway tissues have been reported [14][15][16] and many growth factors have been demonstrated to have mitogenic effects on ASM in culture [17][18][19][20]. Cysteinyl (cys)-leukotrienes (LTs) are known to be involved in allergen-induced ASM cell proliferation in vivo [21,22] but in vitro these substances are weak mitogens for ASM [23,24]. In the sensitised mouse, cys-LT 1 receptor (cys-LT 1 R) antagonism prevents an increase in ASM thickening after repeated allergen challenge [25,26]. It is possible that the effects of cys-LTs in vivo are indirect and mediated by altering the expression of or potentiating the effects of tyrosi...

Accidental chlorine (Cl 2 ) gas inhalation is a common cause of acute airway injury. However, little is known about the kinetics of airway injury and repair after Cl 2 exposure. We investigated the time course of airway epithelial damage and repair in mice after a single exposure to a high concentration of Cl 2 gas. Mice were exposed to 800 ppm Cl 2 gas for 5 minutes and studied from 12 hrs to 10 days post-exposure. The acute injury phase after Cl 2 exposure (≤ 24 hrs post-exposure) was characterized by airway epithelial cell apoptosis (increased TUNEL staining) and sloughing, elevated protein in bronchoalveolar lavage fluid, and a modest increase in airway responses to methacholine. The repair phase after Cl 2 exposure was characterized by increased airway epithelial cell proliferation, measured by immunoreactive proliferating cell nuclear antigen (PCNA), with maximal proliferation occurring 5 days after Cl 2 exposure. At 10 days after Cl 2 exposure the airway smooth muscle mass was increased relative to controls, suggestive of airway smooth muscle hyperplasia and there was evidence of airway fibrosis. No increase in goblet cells occurred at any time point. We conclude that a single exposure of mice to Cl 2 gas causes acute changes in lung function, including pulmonary responsiveness to methacholine challenge, associated with airway damage, followed by subsequent repair and airway remodelling.