PubMed · 15410037
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E DI LAURO. 1949. [Bronchography].. https://pubmed.ncbi.nlm.nih.gov/15410037/
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The composition of the airway epithelium is dynamic and epithelial differentiation is regulated by endogenous mediators as well as inhaled substances. In atopic asthma the differentiation of the epithelium is altered. Various studies have addressed the ability of cultured airway epithelial cells to release the eosinophil-attractant chemokines eotaxin, eotaxin-2 and eotaxin-3 using epithelial cell lines or poorly differentiated primary cells. Since little is known about the role of the epithelial differentiation state in the response of epithelial cells to stimuli that increase production of mediators such as the eotaxins, we analyzed the effect of differentiation state on the production of the eotaxins. In particular, we investigated the effects of the Th2 cytokines IL-4 and IL-13 on eotaxin-2 and -3 production by primary human bronchial epithelial cells and examined whether their production is affected by epithelial cell differentiation using both submerged and air-liquid interface (ALI) cultures. The results show that both IL-4 and IL-13 increase eotaxin-2 and -3 mRNA expression and protein release in submerged- and ALI-cultures. Moreover, epithelial differentiation in ALI-cultures appeared an important determinant in the regulation of eotaxin-2 and -3. Mucociliary differentiation of the epithelial cells was induced by culture in the presence of a high concentration of retinoic acid (RA), whereas low concentrations of RA resulted in a flattened squamous epithelial phenotype. Mucociliary differentiated ALI-cultures expressed and released more eotaxin-3 upon stimulation with IL-4/IL-13, whereas eotaxin-2 production was predominantly found in squamous differentiated ALI-cultures. TNFalpha reduced IL-4-induced eotaxin-2 release in submerged cultures but not in ALI-cultures; no effects on eotaxin-3 synthesis were observed. The results indicate that epithelial differentiation is an important determinant in Th2 cytokine-induced eotaxin-2 and -3 release by airway epithelial cells. These findings may provide new insights into the role of airway epithelial differentiation and Th2 cytokines in the pathogenesis of inflammatory lung disorders such as asthma.
BACKGROUND: Recognition of repeat unmethylated CpG motifs from bacterial DNA through Toll-like receptor (TLR-9) has been shown to induce interleukin (IL)-8 expression in immune cells. We sought to investigate the role of CpG oligodeoxynucleotides (ODN) on a human bronchial epithelial cells. METHODS: RT-PCR and Western blot analysis were used to determine expression of TLR-9 in human bronchial epithelial cells (16HBE14o-). Cells were treated with CpG ODN in the presence or absence of IL-1beta and IL-8 protein was determined using ELISA. In some cases cells were pretreated with chloroquine, an inhibitor of TLR-9 signaling, or SB202190, an inhibitor of the mitogen activated protein kinase p38, prior to treatment with IL-1beta and CpG. TLR9 siRNA was used to silence TLR9 prior to treatment with IL-1beta and CpG. IkappaBalpha and p38 were assessed by Western blot, and EMSA's were performed to determine NF-kappaB activation. To investigate IL-8 mRNA stability, cells were treated with IL-1beta in the absence or presence of CpG for 2 h and actinomycin D was added to induce transcriptional arrest. Cells were harvested at 15 min intervals and Northern blot analysis was performed. RESULTS: TLR-9 is expressed in 16HBE14o- cells. CpG synergistically increased IL-1beta-induced IL-8 protein abundance, however treatment with CpG alone had no effect. CpC (a control ODN) had no effect on IL-1beta-induced IL-8 levels. In addition, CpG synergistically upregulated TNFalpha-induced IL-8 expression. Silencing TLR9 using siRNA or pretreatment of cells with chloroquine had little effect on IL-1beta-induced IL-8 levels, but abolished CpG-induced synergy. CpG ODN had no effect on NF-kappaB translocation or DNA binding in 16HBE14o- cells. Treatment with CpG increased phosphorylation of p38 and pretreatment with the p38 inhibitor SB202190 attenuated the synergistic increase in IL-8 protein levels. Analysis of the half-life of IL-8 mRNA revealed that IL-8 mRNA had a longer half-life following the co-treatment of CpG and IL-1beta compared to treatment with IL-1beta alone. CONCLUSION: Together, these data demonstrate that CpG modulates IL-8 synthesis in the presence of a pro-inflammatory mediator utilizing TLR9 and post-transcriptional mechanisms involving the activation of p38 and stabilization of IL-8 mRNA.
Congenital esophageal stenosis due to tracheobronchial remnants is a rare malformation whose diagnosis may be difficult. It is characterised by the abnormal presence of congenital tissue of tracheal origin in the esophageal wall, which is responsible for the narrowing of the esophagus. We report 2 cases whose treatment was surgical after failure of esophageal dilations. The presence of tracheal-bronchial tissue was confirmed by histological examination of the operative piece. Outcome was favourable and the final result was excellent. Recently, endoscopic ultrasonography has been proved useful in the diagnosis of congenital esophageal stenosis due to tracheobronchial remnants by showing the presence of cartilage, which explains the failure of dilation. The high rate of perforation in these cases is due to brutal fragmentation of the cartilaginous rings. Surgical resection of esophageal stenosis with the tracheobronchial tissue appears the only treatment susceptible to completely suppress the stenosis and its consequences.