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Clarithromycin is a 14-membered macrolide antibiotic. Low-dose, long-term macrolide therapy is effective in patients with chronic airway diseases, such as diffuse panbronchitis, chronic bronchitis, and chronic sinusitis. However, the mechanism underlying this clinical efficacy remains unclear. The dual specificity phosphatase MKP-1 (MAPK phosphatase-1), also called DUSP (dual specificity phosphatase-1), was initially identified as an in vitro ERK-specific phosphatase, but depending on the cell type, it can also dephosphorylate other members of the MAPK family, such as p38 and JNK, and thus suppress downstream signaling of these kinases. It was recently reported that MKP-1 appears to mediate the effects of several anti-inflammatory drugs, including glucocorticoids, but the role of MKP-1 on mucin gene expression in the presence of macrolides in the human airway remains unknown. Here, we demonstrate that the MKP-1 protein is induced by clarithromycin and that clarithromycin suppresses TNF-α-induced MUC5AC mucin gene expression in a p38 MAPK-dependent manner in human airway epithelial (NCI-H292) cells. Our study thus provides new insights into the role of MKP-1 in mediating the effects of macrolides and may help in the development of new therapeutic strategies against mucin overproduction.

Primary ciliary dyskinesia (PCD) is a genetic disease inherited in an autosomal recessive manner. The prevalence of PCD is estimated to be 1 in 20,000 live births. Congenital abnormality of the primary cilia results in situs inversus in 50% of patients. Decreased function of motile cilia causes chronic rhinosinusitis, otitis media with effusion, bronchiectasis and infertility. Cases with situs inversus are considered to show "Kartagener's syndrome", and diagnosis is not difficult. However, in cases without situs inversus, the diagnosis is much more troublesome. PCD without situs inversus is thus probably underdiagnosed. Prolonged chronic cough represents an important symptom that is seen in most patients. The diagnosis of PCD requires the presence of the characteristic clinical phenotypes and either: (1) specific ciliary ultrastructural defects identified by transmission electron microscopy in biopsy samples of respiratory epithelium; or (2) identification of mutation in one of the genes known to be associated with PCD. Nasal nitric oxide concentration is extremely low in PCD, and this could be useful for screening of the disease. At present, no fundamental therapies are available for PCD. Diagnosis in the early stages is important to prevent progression of bronchiectasis and deterioration of lung function by guidance for daily life, immunization, cessation of smoking and prompt therapy at the time of respiratory tract infection. Since PCD is inherited in an autosomal-recessive manner, genetic counseling is necessary after definite diagnosis.

Gram-positive bacterium Streptococcus pneumoniae is an important human pathogen that colonizes the upper respiratory tract and is also the major cause of morbidity and mortality worldwide. S. pneumoniae causes invasive diseases such as pneumonia, meningitis, and otitis media. Despite the importance of pneumococcal diseases, little is known about the molecular mechanisms by which S. pneumoniae-induced inflammation is regulated, especially the negative regulatory mechanisms. Here we show that S. pneumoniae activates nuclear factor of activated T cells (NFAT) signaling pathway and the subsequent up-regulation of inflammatory mediators via a key pneumococcal virulence factor, pneumolysin. We also demonstrate that S. pneumoniae activates NFAT transcription factor independently of Toll-like receptors 2 and 4. Moreover, S. pneumoniae induces NFAT activation via both Ca2+-calcineurin and transforming growth factor-β-activated kinase 1 (TAK1)-mitogen-activated protein kinase kinase (MKK) 3/6-p38α/β-dependent signaling pathways. Interestingly, we found for the first time that tumor suppressor cylindromatosis (CYLD) acts as a negative regulator for S. pneumoniae-induced NFAT signaling pathway via a deubiquitination-dependent mechanism. Finally, we showed that CYLD interacts with and deubiquitinates TAK1 to negatively regulate the activation of the downstream MKK3/6-p38α/β pathway. Our studies thus bring new insights into the molecular pathogenesis of S. pneumoniae infections through the NFAT-dependent mechanism and further identify CYLD as a negative regulator for NFAT signaling, thereby opening up new therapeutic targets for these diseases.

In review of the past studies on NF-kappaB regulation, most of them have focused on investigating how NF-kappaB is activated by a single inducer at a time. Given the fact that, in mixed bacterial infections in vivo, multiple inflammation inducers, including both nontypeable Haemophilus influenzae (NTHi) and Streptococcus pneumoniae, are present simultaneously, a key issue that has yet to be addressed is whether NTHi and S. pneumoniae simultaneously activate NF-kappaB and the subsequent inflammatory response in a synergistic manner. Here, we show that NTHi and S. pneumoniae synergistically induce NF-kappaB-dependent inflammatory response via activation of multiple signaling pathways in vitro and in vivo. The classical IKKbeta-IkappaBalpha and p38 MAPK pathways are involved in synergistic activation of NF-kappaB via two distinct mechanisms, p65 nuclear translocation-dependent and -independent mechanisms. Moreover, casein kinase 2 (CK2) is involved in synergistic induction of NF-kappaB via a mechanism dependent on phosphorylation of p65 at both Ser536 and Ser276 sites. These studies bring new insights into the molecular mechanisms underlying the NF-kappaB-dependent inflammatory response in polymicrobial infections and may lead to development of novel therapeutic strategies for modulating inflammation in mixed infections for patients with otitis media and chronic obstructive pulmonary diseases.

The transforming growth factor beta (TGF-beta) pathway represents an important signaling pathway involved in the regulation of diverse biological processes, including cell proliferation, differentiation, and apoptosis. Despite the known role of TGF-betaR-mediated signaling in suppressing immune response, its role in regulating human Toll-like receptors (TLRs), key host defense receptors that recognize invading bacterial pathogens, however, remains unknown. Here, we show for the first time that TGF-betaR-Smad3/4 signaling pathway acts as a positive regulator for TLR2 induction by bacterium nontypeable Hemophilus influenzae (NTHi) in vitro and in vivo. The positive regulation of TLR2 induction by TGF-betaR is mediated via a dual mechanism involving distinct signaling pathways. One mechanism involves functional cooperation between the TGF-betaR-Smad3/4 pathway and NF-kappaB pathway. Another involves MAP kinase phosphatase 1 (MKP-1)-dependent inhibition of p38 MAPK, a known negative regulator for TLR2 induction. Moreover, we showed that TbetaR-mediated signaling is probably activated by NTHi-derived TGF-beta mimicry molecule via an autocrine-independent mechanism. Thus, our study provides new insights into the role of TGF-beta signaling in positively regulating host defense response by tightly controlling the expression level of TLR2 during bacterial infections and may lead to new therapeutic strategies for modulating host defense and inflammatory response.

Objectives: The purpose of the study is to know if mucin gene expression can be detected in the middle ear effusion and if so, which mucin genes are expressed in the effusions. Methods: Mucin gene expression in the middle ear effusions obtained from five patients with otitis media with effusion were analyzed by reverse transcription-polymerase chain reaction. Ribonucleic acids (RNAs) were extracted from the effusion and the expression of 12 mucin genes was analyzed by reverse transcription-polymerase chain reaction. Results: Mucin gene expression examined by reverse transcription-polymerase chain reaction indicated the expression of MUC1 , MUC4 , MUC5AC , MUC6 , MUC7 , MUC8 , MUC9 , MUC11 and MUC12 mRNA in the effusion. This mucin gene expression was similar to that in BEAS-2B cell, a bronchial epithelial cell line. Conclusion: Middle ear effusion can give us valuable information on mucin gene expression in the middle ear. There is similarity between mucin gene expression in the middle ear effusion and that in the bronchial epithelia.