Role of cathepsin S in ozone-induced airway hyperresponsiveness and inflammation.

Ambient ozone has been linked to the worsening of symptoms of patients with obstructive diseases such as chronic obstructive pulmonary disease (COPD) and asthma. We investigated the role of cathepsin S on ozone-induced airway hyperresponsiveness (AHR) and inflammation, using the selective cathepsin S inhibitor, Compound A. Balb/c mice were exposed to ozone at a concentration of 3 ppm or air for 3 h, following administration by gavage of Compound A or vehicle. Bronchoalveolar lavage (BAL) was performed 3 h and 20-24 h following exposure, AHR was measured at 20-24 h only. Ozone exposure, compared to air exposure increased BAL cathepsin S levels, AHR and BAL inflammatory cells. Compound A (30 mg kg(-1) p.o.) dosing compared to vehicle dosing inhibited ozone-induced AHR (-logPC100 vehicle: -0.70+/-0.12, n=8 vs. cathepsin S inhibitor: -1.30+/-0.06, P<0.001, n=8) at 20-24 h and BAL neutrophilia at 3 h and 20-24 h (P<0.05, n=6). Ozone exposure increased levels of BAL cytokines IL-6, TNF-alpha and IFN-gamma. Compound A reduced IL-6 at 3 h and 20-24 h (P<0.05, n=5) and TNF-alpha, at 20-24 h (P<0.05, n=6). These data indicate an important role for cathepsin S in the regulation of ozone-induced AHR and neutrophil cell recruitment and suggest that cathepsin S may be a target in the treatment of oxidative stress-induced AHR and inflammation.

Pivotal roles of CD8+ T cells restricted by MHC class I-like molecules in autoimmune diseases.

Unlike T cells restricted by major histocompatibility complex (MHC) class Ia or class II molecules, T cells restricted by MHC class I-like molecules demonstrate properties of both innate and adaptive immunity and are therefore considered innate-like lymphocytes (ILLs). ILLs are believed to have immunoregulatory functions, but their roles in autoimmunity and defense against infections remain elusive. To study the properties of ILLs, we generated mice expressing only MHC class I-like molecules by crossing CIITA-/- with Kb-/-Db-/- mice. Surprisingly, these mice developed a lymphoproliferative syndrome and autoimmunity, most notably inflammatory bowel disease (IBD) and insulitis. The CD8+ ILLs in these mice exhibit a constitutively activated phenotype, and depletion of these cells abolished the autoimmune disorders. In addition, adoptive transfer of CD8+ ILLs from Kb-/-Db-/-CIITA-/- mice to Rag-1-/-pfn-/- mice also resulted in IBD and insulitis. These findings provide direct evidence that CD8+ ILLs are sufficient to initiate and mediate autoimmune diseases.

Effects of ciclesonide and fluticasone propionate on allergen-induced airway inflammation and remodeling features.

BACKGROUND: Several topical corticosteroids are available as anti-inflammatory treatment for asthma. Their comparative effects on allergic inflammation and airway remodeling are unclear. OBJECTIVE: We compared the effects of ciclesonide with those of fluticasone propionate in a Brown Norway rat model of chronic allergic asthma. METHODS: Rats sensitized and exposed to ovalbumin (OVA) were treated with dry powder vehicle, ciclesonide, or fluticasone (0.01, 0.03, and 0.1 mg/kg administered intratracheally) 24 hours and 1 hour before each of 6 OVA exposures. In a second protocol we administered 0.1 mg/kg ciclesonide or fluticasone only after the third OVA exposure. RESULTS: Ciclesonide at all doses inhibited the allergen-induced increase in airway eosinophils and T cells, reduced goblet cell hyperplasia, and decreased 5-bromo-2'-deoxyuridine-immunoreactive airway smooth muscle (ASM) and epithelial cells. At 0.03 and 0.1 mg/kg ciclesonide, bronchial hyperresponsiveness (BHR) was also inhibited. Fluticasone did not attenuate allergen-induced BHR, despite inhibiting airway eosinophils and T cells, goblet cell hyperplasia, and 5-bromo-2'-deoxyuridine-immunoreactive ASM and epithelial cells. Fluticasone (0.1 mg/kg) caused a significant reduction in body weight (9%) compared with ciclesonide (0.1 mg/kg). Ciclesonide did not change plasma corticosterone levels, whereas fluticasone (0.1 mg/kg) reduced them. In the second protocol both fluticasone and ciclesonide inhibited BHR, bronchial inflammation, goblet cell hyperplasia, and ASM proliferation. CONCLUSION: Ciclesonide potently inhibited chronic allergic inflammation, remodeling, and BHR without having an effect on body weight and the hypothalamic-pituitary-adrenal axis. Fluticasone prevented airway inflammation but not BHR, but both fluticasone and ciclesonide are effective at reversal of BHR, inflammation, and remodeling features.

Effect of an inhibitor of Jun N-terminal protein kinase, SP600125, in single allergen challenge in sensitized rats.

Jun N-terminal kinase (JNK) has been implicated in the pathogenesis of inflammatory diseases including asthma. We examined the effect of SP600125 (anthra [1,9-cd] pyrazol-6 (2H)-one), a novel inhibitor of JNK in a model of asthma. Brown-Norway rats were sensitized to ovalbumin and treated with SP600125 intraperitoneally (90 mg/kg in total). SP600125 inhibited allergen-induced, increased activity of phosphorylated c-jun but not of phosphorylated-MAPKAPK2, indicative of activation of p38 MAPK, in the lung. SP600125 inhibited macrophage (P < 0.04), lymphocyte (P < 0.05), eosinophil (P < 0.04) and neutrophil (P < 0.005) numbers in bronchoalveolar lavage. Eosinophil and T-cell accumulation in the airways, mRNA expression for interleukin-1beta, tumour necrosis factor-beta, interleukin-3, interleukin-4 and interleukin-5, serum levels of allergen-specific immunoglobulin E and bronchial hyperresponsiveness were not affected by SP600125. Selective inhibition of JNK reduced inflammatory cell egress into the airway lumen after single allergen exposure. The role of JNK mitogen-activated protein kinase activation may be limited in the pathogenesis of bronchial hyperresponsiveness after single allergen exposure.

Distribution of respiratory mucin proteins in human nasal mucosa.

OBJECTIVES/HYPOTHESIS: The upper respiratory tract is involved in many acute and chronic respiratory tract diseases that present with the symptom of mucus hypersecretion. Mucin genes that encode for the backbone of glycoproteins contribute to the viscoelastic property of airway mucus. We examined the cellular expression and distribution of two major respiratory mucus-forming glycoproteins, MUC5AC and MUC5B, in normal human nasal tissues. METHODS: Immunohistochemical analysis using polyclonal antibodies against the mucins MUC5AC and MUC5B was performed in normal human nasal tissues. RESULTS: An abundant staining of submucosal mucus gland and epithelial goblet cells for MUC5B was found. Immunohistochemical analysis of MUC5AC showed staining of surface epithelium goblet cells, whereas there was no staining of glandular cells. Comparison of the expression to lower airways revealed a similar pattern of expression of both mucins. CONCLUSIONS: The data in the present study demonstrated the localization of the two major respiratory mucin proteins in human nasal mucosa with a similar distribution of expression of MUC5AC and MUC5B in normal upper and lower airways. Mucin protein expression parallels that of mucin messenger RNA expression.