HSP27 elevated in mild allergic inflammation protects airway epithelium from H2SO4 effects.

Inflammation in allergic individuals is hypothesized to elevate stress proteins [heat shock proteins (HSP)] in airway epithelium, which may protect cells from further adverse conditions. Allergic, either asthmatic or not, and normal volunteers participated in a 2-day segmental allergen challenge bronchoscopic procedure. Bronchial epithelium was obtained before and after challenge. Epithelium was exposed to medium with H2SO4 (pH5), returned to medium at pH 7.4, and finally harvested for Western blotting with anti-27-kDa HSP (HSP27) antibody. Prechallenge epithelium of all subjects had significantly inhibited ciliary function by H2SO4 (pH 5) conditions (P < 0.001); only epithelium of normals recovered (P = 0.02). Allergic subjects with mild inflammation (< 50 micrograms/ml increase in albumin in bronchoalveolar lavage) had significantly increased HSP27 postchallenge (P = 0.01) and little ciliary dysfunction at pH 5, whereas subjects with severe inflammation (> 50 micrograms/ml increase in albumin) had little change in HSP27 and significant ciliary inhibition (P = 0.02). Normal epithelium had similar trends in HSP27 and equivalent inhibition of ciliary activity at pH 5 before and after allergen challenge. These data indicate that mild inflammation to allergen elevates HSP27 stress protein levels, thereby potentially protecting epithelial function from additional adverse conditions.

Beta 2-agonist-elevated stress response in human bronchial epithelial cells in vivo and in vitro.

Recent studies report high baseline levels of stress (heat shock) proteins in bronchial epithelial cells from asthmatic individuals. The promoter of the gene encoding the 72-kDa heat shock protein has an element responsive to cAMP, which may be affected by beta-agonists. This study examined stress protein levels in subjects enrolled in a segmental lung allergen challenge study to determine whether beta-agonist medication could contribute to a stress response. Subjects were divided on the basis of no premedication (n = 17), metered dose inhalations of albuterol (n = 24), or placebo inhalation (n = 3) prior to bronchoscopy. Levels of the inducible stress protein Hsp72 and constitutive Hsp73 were quantitated in bronchial epithelial cells from brush biopsy of allergic nonasthmatic, allergic asthmatic, and normal individuals. Mean levels were increased significantly (p < 0.003 and p < 0.004, respectively) in those subjects who received albuterol premedication. No significant differences were found between clinical groups of individuals or for placebo inhalation vs nonpremedication. Albuterol in vitro increased the levels of Hsp72 and Hsp73 in epithelial cells from either nonpremedicated or placebo-treated donors; the Hsp72 levels correlated linearly with increased albuterol concentration (r = 0.81, p < 0.01). Therefore, beta-agonists elevate or prolong an elevated stress response in epithelial cells, possibly through cAMP-mediated effects.

IL-1 beta release from cultured bronchial epithelial cells and bronchoalveolar lavage cells from allergic and normal humans following segmental challenge with ragweed.

This work investigated whether interleukin 1 beta (IL-1 beta) release from epithelial cells is modulated by antigen challenge in vivo, and inflammatory cells in vitro. Bronchial epithelial cells were obtained before and after segmental allergen challenge in allergic and normal individuals, and were cultured with and without autologous bronchoalveolar lavage (BAL) cells. IL-1 beta in culture medium was quantitated by enzyme-linked immunoabsorbent assay (ELISA). Pre-challenge IL-1 beta levels from epithelial cells were similar in allergic (4.4 +/- 0.8 pg/ml, n = 32) and normal (6.8 +/- 1.7 pg/ml, n = 17) subjects. IL-1 beta levels were significantly elevated from epithelium with BAL cell co-culture vs without co-culture in both subject groups (allergic, 13.2 +/- 2.3 pg/ml, P = 0.006; normal: 16.4 +/- 4.0 pg/ml, P = 0.007). Post-challenge IL-1 beta from epithelial cells without BAL cells was increased in both groups, but significant only for allergic subjects (P = 0.003). Post-challenge IL-1 beta from epithelial with BAL cells changed little for allergic subjects (13.8 +/- 2.4 pg/ml), and increased for normal subjects (20.0 +/- 4.8 pg/ml). Decreased production of tumour necrosis factor alpha (TNF-alpha) was observed in allergic subjects (day 1: 447 pg/ml vs day 2: 258 pg/ml). Moreover, pre-challenge release of TNF-alpha and IL-1 beta levels from epithelial + BAL cells correlated well for allergic (r = 0.84) and normal subjects (r = 0.6), but post-challenge release correlated only in normal subjects (r = 0.90). These results indicate that bronchial epithelial cells and BAL cells interact, modulating release of these inflammatory cytokines.