Cigarette smoking is the major risk factor for developing chronic bronchitis, yet only 15-20% of smokers develop this disorder. Because oxidants are the major mechanism of smoking-induced airway damage, we hypothesized that smoking is associated with upregulation of various antioxidant-related genes in the airway epithelium, but the magnitude of the response shows high interindividual variability. Microarray analysis was used to assess levels of expression of 44 antioxidant-related genes in four categories (catalase/superoxide dismutase family; glutathione metabolism; redox balance; and pentose phosphate cycle) in bronchoscopyobtained airway epithelium of matched cohorts (13 current smokers, 9 nonsmokers), none of whom had lung disease. There was minimal variation in gene expression levels within the same individual (right versus left lung or over time), but significant upregulation of 16/44 antioxidant-related genes in smoker epithelium compared with nonsmokers. Subgroups of smokers were identified with clusters of expression levels of antioxidantrelated genes. We propose that the antioxidant-related genes demonstrating the most variability in the level of expression in smokers may be useful genetic markers in epidemiologic studies assessing susceptibility to smoking-induced chronic bronchitis.Chronic bronchitis, a common form of chronic obstructive pulmonary disease (COPD) associated with persistent inflammation and pathogen colonization of the airway epithelium, is defined clinically by the presence of a chronic productive cough for at least 3 mo in two consecutive years in an individual in whom other causes of chronic cough have been excluded (1). Cigarette smoking is the major risk factor for the development of chronic bronchitis, and there is a dose-dependent link of the cumulative amount of smoking and the incidence of the disease (2, 3). Compelling evidence supports the concept that the pathogenesis of chronic bronchitis is associated with the chronic stress of oxidants in cigarette smoke overwhelming the antioxidant defenses of the airway epithelium, resulting in persistent injury to the airways (4, 5). Despite the clear link of smoking to the risk for chronic bronchitis, only 15-20% of cigarette smokers develop COPD (3, 6), suggesting that there must be risk factors other than smoking that contribute to the susceptibility to this disease. Clues that genetic variability plays an important role come from studies demonstrating familial clustering of impaired lung function in response to smoking, and studies documenting susceptibility to smoking-related airflow obstruction in twins (3,7,8). In this context, the focus of this study is to identify candidate genes linked to the risk for chronic bronchitis in association with cigarette smoking. Because it is the airway epithelium that takes the brunt of the oxidant burden in cigarette smoke, we hypothesize that the airway epithelium responds to smoking by upregulating the expression of genes related to antioxidant protection, but the response to cigarette smok...

A lung/liver-on-a-chip platform with metabolic capability over 28 days: a fit-for-purpose microfluidic system for toxicity assessment of pulmonary toxicants.

Cigarette smoking is the leading cause of the respiratory diseases collectively known as chronic obstructive pulmonary disease (COPD). While the pathogenesis of COPD is complex, there is abundant evidence that alveolar macrophages (AM) play an important role. Based on the concept that COPD is a slow-progressing disorder likely involving multiple mediators released by AM activated by cigarette smoke, the present study focuses on the identification of previously unrecognized genes that may be linked to early events in the molecular pathogenesis of COPD, as opposed to factors associated with the presence of disease. To accomplish this, microarray analysis using Affymetrix microarrays was used to carry out an unbiased survey of the differences in gene expression profiles in the AM of phenotypically normal, approximately 20 pack-year smokers compared to healthy nonsmokers. Although smoking did not alter the global gene expression pattern of AM, 75 genes were modulated by smoking, with 40 genes up-regulated and 35 down-regulated in the AM of smokers compared to nonsmokers. Most of these genes belong to the functional categories of immune/inflammatory response, cell adhesion and extracellular matrix, proteolysis and antiproteolysis, lysosomal function, antioxidant-related function, signal transduction, and regulation of transcription. Of these 75 genes, 69 have not been previously recognized to be up- or down-regulated in AM in association with smoking or COPD, including genes coding for proteins belonging to all of the above categories, and others belonging to various functional categories or of unknown function. These observations suggest that gene expression responses of AM associated with the stress of cigarette smoking are more complex than previously thought, and offer a variety of new insights into the complex pathogenesis of smoking-induced lung diseases.

Chronic obstructive pulmonary disease (COPD) is one of the most prevalent lung diseases. Cigarette smoking is the main risk factor for COPD. In this parallel-group clinical study we investigated to what extent the transitions in a chronic-exposure-to-disease model are reflected in the proteome and cellular transcriptome of induced sputum samples. We selected 60 age- and gender-matched individuals for each of the four study groups: current asymptomatic smokers, smokers with early stage COPD, former smokers, and never smokers. The cell-free sputum supernatant was analyzed by quantitative proteomics and the cellular mRNA fraction by gene expression profiling. The sputum proteome of current smokers clearly reflected the common physiological responses to smoke exposure, including alterations in mucin/trefoil proteins and a prominent xenobiotic/oxidative stress response. The latter response also was observed in the transcriptome, which additionally demonstrated an immune-cell polarization change. The former smoker group showed nearly complete attenuation of these biological effects. Thirteen differentially abundant proteins between the COPD and the asymptomatic smoker group were identified including TIMP1, APOA1, C6orf58, and BPIFB1 (LPLUNC1). In summary, our study demonstrates that sputum profiling can capture the complex and reversible physiological response to cigarette smoke exposure, which appears to be only slightly modulated in early-stage COPD.

X-linked immunodeficiency with hyper-IgM (HIGM1), characterized by failure of immunoglobulin isotype switching, is caused by mutations of the CD40 ligand (CD40L), which is normally expressed on activated CD4(+) T cells. As constitutive expression of CD40L induces lymphomas, we corrected the mutation while preserving the natural regulation of CD40L using pre-mRNA trans-splicing. Bone marrow from mice lacking CD40L was modified with a lentivirus trans-splicer encoding the normal CD40L exons 2-5 and was administered to syngenic CD40L-knockout mice. Recipient mice had corrected CD40L mRNA, antigen-specific IgG1 responses to keyhole limpet hemocyanin immunization, regulated CD4(+) T-cell CD40L expression after CD3 stimulation in primary and secondary transplanted mice, attenuation of Pneumocystis carinii pneumonia, and no evidence of lymphoproliferative disease over 1 year. Thus, HIGM1 can be corrected by CD40L trans-splicing, leading to functional correction of the genetic defect without the adverse consequences of unregulated expression of the CD40L gene.