Alveolar macrophage activation and an emphysema-like phenotype in adiponectin-deficient mice.

Adiponectin is an adipocyte-derived collectin that acts on a wide range of tissues including liver, brain, heart, and vascular endothelium. To date, little is known about the actions of adiponectin in the lung. Herein, we demonstrate that adiponectin is present in lung lining fluid and that adiponectin deficiency leads to increases in proinflammatory mediators and an emphysema-like phenotype in the mouse lung. Alveolar macrophages from adiponectin-deficient mice spontaneously display increased production of tumor necrosis factor-alpha (TNF-alpha) and matrix metalloproteinase (MMP-12) activity. Consistent with these observations, we found that pretreatment of alveolar macrophages with adiponectin leads to TNF-alpha and MMP-12 suppression. Together, our findings show that adiponectin leads to macrophage suppression in the lung and suggest that adiponectin-deficient states may contribute to the pathogenesis of inflammatory lung conditions such as emphysema.

Exogenous interleukin-16 inhibits antigen-induced airway hyper-reactivity, eosinophilia and Th2-type cytokine production in mice.

BACKGROUND: IL-16 has been described as a natural soluble CD4-ligand with immunosuppressive effects in vitro. However, little is known about the effect of IL-16 on immune responses in vivo. OBJECTIVE: In the present study, we examined the effect of IL-16 administration in a murine model of allergic asthma. Next, we determined whether these effects were mediated by modulation of CD4+ T lymphocytes. METHODS AND RESULTS: Intraperitoneal administration of IL-16 completely inhibits antigen-induced airway hyper-responsiveness and largely decreases the number of eosinophils in bronchoalveolar lavage fluid (> 90%) and airway tissue of ovalbumin-sensitized and challenged mice. Firstly, it appears that thoracic lymph node cells isolated from in vivo IL-16-treated ovalbumin-challenged animals produce less IL-4 (77%) and IL-5 (85%) upon antigenic re-stimulation, when compared to vehicle-treated mice. Secondly, pre-incubation of lymphocytes with IL-16 in vitro reduces antigen-induced proliferation (55%) and Th2-type cytokine production (IL-4; 56%, IL-5; 77%). Thirdly, the presence of IL-16 during priming cultures of TCR transgenic T cells (DO11.10), reduces IL-4 (33%) and IL-5 (35%), but not IL-10 and IFNgamma levels upon re-stimulation. CONCLUSION: It can be concluded that IL-16 has potent immunosuppressive effects on a Th2dominated allergic airway response.

Il-9 stimulates release of chemotactic factors from human bronchial epithelial cells.

Interleukin (IL)-9 is a T helper 2 cytokine implicated as a candidate gene and contributor to human asthma. We hypothesized that the inflammatory potential of bronchial epithelium is affected by its local environment and explored this hypothesis with respect to the effect of IL-9 on bronchial epithelium. We investigated the response of primary and immortalized human bronchial epithelial cells to IL-9 stimulation with respect to the release of T-cell chemoattractant factors. In response to IL-9, the HBE4-E6/E7 cell line, but not BEAS-2B cells, released the T-cell chemoattractants IL-16 and regulated on activation, normal T cells expressed and secreted (RANTES) in a dose-dependent fashion. We found a similar dose response to IL-9 in primary cells from bronchial brushings of healthy subjects and that nearly all of the T-cell chemoattraction was attributable to IL-16 and RANTES. Reverse transcriptase/polymerase chain reaction of BEAS-2B, HBE4-E6/E7, and primary cells from two subjects revealed messenger RNA for IL-9 receptor (IL-9R) alpha but not in BEAS-2B cells. Fluorescence-activated cell sorter analysis of HBE4-E6/E7 and primary cells confirmed surface expression of the IL-9 receptor. Costimulation of both cell types with IL-9 and antibody to either gamma-common chain or IL-9Ralpha completely blocked the release of T-cell chemoattractant activity, confirming the primary role of a functioning IL-9 receptor for IL-9 signaling in HBE4-E6/E7 and primary bronchial epithelial cells. We conclude that IL-9 is a stimulus for airway epithelial cell release of T-cell chemoattractant factors, which in turn may modulate the immune response in allergic airway inflammation.

Rhinovirus-16 colds in healthy and in asthmatic subjects: similar changes in upper and lower airways.

Rhinovirus (RV) infections appear to precipitate most asthma exacerbations. To investigate whether RV-16 induces different inflammatory changes in upper and lower airways of asthmatic and healthy subjects, we inoculated 10 nonatopic healthy and 11 atopic asthmatic adults with 2,000 TCID50 RV-16. Subjects recorded symptoms and peak flow daily; and they underwent spirometry, methacholine challenge (PC20), nasal lavage, and sputum induction at baseline and on Days 2, 4, 15, and 29 d after inoculation. One asthmatic subject developed an exacerbation requiring prednisone treatment 5 d after inoculation. The cold symptom severity (Jackson score) did not differ between groups. During the cold, asthma symptoms increased slightly from baseline in the asthmatic group; and PC20 decreased in the healthy group. However, peak flow, bronchodilator use, and spirometry did not change in either group. At baseline, asthmatics had higher neutrophils, eosinophils, and interleukin (IL)-6 in nasal lavage. After inoculation, both groups developed significant increases in nasal neutrophils, IL-6 and IL-8, and modest increases in sputum neutrophils and IL-6, but not IL-8. However, these changes did not differ between groups. IL-5, interferon-gamma, and RANTES were detected only in nasal lavages from two asthmatic subjects, who had the most severe colds. IL-11 was not detected in any sample. We conclude that inflammatory responses of upper and lower airways during RV-16 colds are similar in asthmatic and healthy subjects, and that RV-16 infection is not by itself sufficient to provoke clinical worsening of asthma.

Sister chromatid exchange in painters recently exposed to solvents.

Epidemiologic studies have suggested that exposure to solvent-based materials in the painting trades is associated with an increased cancer risk. In order to determine if the solvent exposures of current union members of the International Brotherhood of Painters and Allied Tradesman (IBPAT) are associated with a genotoxic risk, we have measured the sister chromatid exchange (SCE) frequency in their peripheral blood lymphocytes. Previous reports have shown that chronic solvent exposure of these workers does not elevate SCE frequencies. We now report that acute exposure, estimated by the number of days worked over the month prior to venipuncture, is associated with elevated SCE levels in currently smoking workers. No elevation in SCE was associated with similar recent exposure in nonsmoking, solvent-exposed painters.

Effects of cigarette smoking and solvent exposure on sister chromatid exchange frequency in painters.

A cross-sectional study of sister chromatid exchange frequency (SCE) in peripheral blood lymphocytes from 117 members of the International Brotherhood of Painters and Allied Tradesman was conducted in union locals in two major U.S. cities. Chronic solvent exposure intensity and duration were estimated from interviewer-administered-questionnaire data. SCE for all of the workers in the study were scored by one reader. A second reader determined the SCE frequency from a random sample of 30 workers. No significant difference in SCE frequency was associated with reader or time of reading. Age, coffee and alcohol intake and chronic solvent exposure (both intensity and duration, estimated over the working lifetime and over the year prior to study for each worker) did not significantly elevate SCE. The effect of smoking on SCE frequency, assessed by analysis of variance controlling for other possible confounding factors, showed that smoking increased SCE frequency (P less than .0001). The SCE frequency in the smoking, solvent-exposed (estimated as lifetime exposure) painters was 6.75 SCE/cell; in the non-smoking, solvent-exposed workers the SCE frequency was 5.73 SCE/cell; the controls had SCE levels of 6.84 SCE/cell (smokers) and 5.90 SCE/cell (non-smokers), respectively. These observations are consistent with other work suggesting that chronic solvent exposure in the paint trade is not associated with an elevation in SCE in peripheral blood lymphocytes. However, further work is necessary to address adequately the question of the genotoxicity of acute solvent exposure in these workers.

Multiple abnormalities in the ultraviolet light response of cultured fibroblasts derived from patients with the basal cell nevus syndrome.

Basal Cell Nevus Syndrome (BCNS) is a rare autosomal-dominant inherited disorder associated with a marked hypersusceptibility to spontaneous and radiation-induced skin cancer. We examined the changes in cell survival, unscheduled DNA synthesis (UDS) and the frequency of sister chromatid exchanges (SCE) induced by ultraviolet light (UVL) in confluent normal and BCNS fibroblasts. BCNS cells appeared slightly hypersensitive to the cytotoxic effects of UVL. The rate of UDS induced by UVL exposure in normal cell strains increased linearly following doses up to 30 J/m2, whereas in BCNS cells UDS became saturated at doses of 10 J/m2 showing no further increase with doses up to 30 J/m2. UDS activity persisted for longer periods after UVL exposure in BCNS as compared with normal cells. The dose-response relationship for UVL-induced SCE was similar in normal and BCNS fibroblasts. However, the frequencies of UVL-induced SCE declined to near background levels in normal cells following 12-24 hr of confluent holding prior to subculture whereas they remained elevated in BCNS cells with holding times up to 24 hr after UVL exposure. Overall, these results suggest that BCNS fibroblasts may have a diminished capacity for the repair of some type of DNA damage as compared with normal fibroblasts.