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Olfactory neuroblastoma is a rare, malignant neoplasm arising from the olfactory epithelium. It has an aggressive biological behavior that is characterized by local recurrence, atypical distant metastasis, and poor long-term prognosis. The incidence of cervical lymph node metastasis in olfactory neuroblastoma is variable, and treatment modalities are controversial. Moreover, few reports have been published concerning retropharyngeal lymph node metastasis from olfactory neuroblastoma. We present two cases of olfactory neuroblastoma with retropharyngeal lymph node metastasis. In addition, we provided a review of the current literature regarding olfactory neuroblastoma and retropharyngeal lymph node metastasis from olfactory neuroblastoma. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental and food contaminants with known or suspected carcinogenic properties. In this study, we have evaluated whether PAHs activate the early growth response (EGR-1) gene and bind to peroxisome proliferator-activated receptor alpha (PPARα) and delta (PPARβ/δ) in cell culture systems. Luciferase reporter systems were employed and several PAHs were evaluated for their ability to activate EGR-1 and PPARs. Some PAHs enhanced EGR-1 expression and activated PPARα and PPARβ. Among them, benz(a)anthracene was found to act as a relatively potent activator of PPARα and PPARβ/δ, and to significantly enhance EGR-1 transcription. These in vitro assays were confirmed by Western blot analysis, using cell lysates of tissue samples from mouse trapped at a highly contaminated Superfund site in the Chattanooga Creek floodplain in Chattanooga, Tennessee. We have found that a PPAR target gene, glycogen synthase kinase-3β (GSK-3β), was down-regulated and EGR-1 was up-regulated in the mouse samples of Chattanooga Creek. In addition, select PAHs repressed GSK-3β and induced CYP4A in FaO rat hepatoma cells. In conclusion, PAHs activate PPARα and PPARβ/δ, and up-regulate EGR-1 expression in vitro as well as in vivo. These data may provide a diversity of PAH activity in several biological pathways. [ABSTRACT FROM AUTHOR]

Conclusions These results demonstrate that sulindac sulfide can induce cell death in maxillary cancer cells, and that sulindac sulfide-induced apoptosis is related to the extracellular signal-regulated kinase/p38 MAPK--caspase 3 signaling pathway. Objective Head and neck cancer is the sixth commonest cancer in the human body. Squamous cell carcinoma accounts for most sinonasal cancers. However, little is known regarding the biochemical mechanism(s) of cell death in sinonasal cancers. Recently, human epidemiological and clinical intervention studies have indicated that sulindac, a non-steroidal anti-inflammatory drug, exhibits chemopreventive activity in colorectal cancer. In this study, we aimed to investigate whether sulindac sulfide can induce apoptosis in sinonasal cancer cells and what type of molecular mechanisms induces the death of sinonasal cancer cells. Material and methods Sinonasal cancer cells (Asan Medical Center--Head and Neck Cancer 5) were treated with various concentrations of sulindac sulfide. The degree of cell death was determined by means of a fluorescence-activated cell scan and the signal transduction pathway for cell death was examined. Results Human nasal cavity cancer cells treated with sulindac sulfide underwent cell death, and the induction of apoptosis occurred in a dose-dependent manner. Moreover, sulindac sulfide-induced apoptosis was abolished by treatment with the caspase inhibitor Z-VAD-fmk and the mitogen-activated protein kinase (MAPK) inhibitors PD98059 and SB203580. [ABSTRACT FROM AUTHOR]

Extracellular purines and pyrimidines regulate various physiological responses via the cell surface receptors known as purinoreceptors and may exert autocrine or paracrine effects on ion transport, fluid transport, ciliary beat frequency, and mucin secretion. Therefore, this study aims to investigate the expression patterns of the purinoreceptors in normal human nasal epithelial (NHNE) cells. In RT-PCR, the mRNAs for several P2X (P2X3, P2X4, P2X7) and P2Y (P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, P2Y12) receptors were identified in NHNE cells. Functional localizations of P2 receptors were investigated by measuring intracellular calcium concentration ([Ca2+]i) increases in membrane-specific manner using a double-perfusion chamber. Absence of the responses of αβ3-methylene ATP and 2-methylthio-ATP excluded functionally active P2X3, P2X4, and P2Y1 receptors as far as [Ca2+]i increase is concerned. Applications with ATP and UTP revealed that luminal membranes of NHNE cells express P2Y2 and P2Y6 receptors and basolateral membranes express P2Y2 receptor. Expressions of P2Y2 and P2Y6 receptors in NHNE cells were further verified by immuno-blotting using specific antibodies. In addition, the results with 2,3-O- (4-benzoyl)-benzoyl-ATP indicate that the P2Y11 receptor may be present on the luminal side. In conclusion, the NHNE cells express functionally active P2Y2, P2Y6, and P2Y11 receptors in a membrane- specific pattern, which may play an important role in the control of mucin and fluid secretion in NHNE cells. [ABSTRACT FROM AUTHOR]

LIM kinase 1 (LIMK1), a novel member of a subclass of the protein-serine/threonine kinases, is known to play a r01e in the development and maintenance of neuronal circuits that mediate cognitive function. Genetic studies have implicated a mutation of LIMK1 as a causative factor in the impairment of visuospatial cognition in a neurodevelopmental disorder, Williams syndrome. A transcriptional factor, cAMP-responsive element-binding protein (CREB), is thought to be involved in the formation of many types of synaptic plasticity involving learning and memory. In the present study we show that the LIMK1 activity is markedly induced during the differentiation of immortalized hippocampal progenitor (H19-7) cells. We found that the addition of neurogenic growth factor to H19-7 cells induces specific binding between LIMK1 and active CREB, that LIMK1 directly phosphorylates CREB, and that this leads to the stimulation of subsequent cAMP-responsive element-mediated gene transcription during H19-7 cell neuronal differentiation. In addition, we also found that LIMK1 activation occurs through Rac/Cdc42- and p21-activated kinase-mediated signaling pathways. Moreover, when the plasmid encoding kinase-inactive LIMK1 was transfected to block the activation of endogenous LIMK1, the neuronal differentiation of H19-7 cells was significantly suppressed. These findings suggest that LIMK1 activation and subsequent CREB phosphorylation are important in the neuronal differentiation of central nervous system hippocampal progenitor cells. [ABSTRACT FROM AUTHOR]

Bruton's tyrosine kinase (BTK) is a member of the Tec family of kinases, which is a subgroup of the nonreceptot cytoplasmic protein tyrosine kinases. BTK has been shown to be important in the proliferation, differentiation, and signal transduction of B cells. Mutations in BTK result in B cell immune deficiency disorders, such as X-linked agammaglobulinemia in humans and X-linked immunodeficiency in mice. Although BTK plays multiple roles in the life of a B cell, its functional role in neuronal cells has not been elucidated. In the present study, we demonstrate that BTK activates transcription factor, cAMP response element (CRE)-binding protein (CREB), and subsequent CRE-mediated gene transcription during basic fibroblast growth factor (bFGF)-induced neuronal differentiation in immortalized hippocampal progenitor cells (H19-7). The kinase activity of BTK is also induced by bFGF, and BTK directly phosphorylates CREB at Ser-133 residue, indicating that BTK has a dual protein kinase activity. In addition, blockading BTK activation significantly inhibits CREB phosphorylation as well as the neurite outgrowth induced by bFGF in H19-7 cells. These results suggest that the activation of BTK and the subsequent phosphorylation of CREB at Ser-133 are important in the neuronal differentiation of hippocampal progenitor cells. [ABSTRACT FROM AUTHOR]

In Drosophila melanogaster, although the NF-κB transcription factors play a pivotal role in the inducible expression of innate immune genes, such as antimicrobial peptide genes, the exact regulatory mechanism of the tissue-specific constitutive expression of these genes in barrier epithelia is largely unknown. Here, we show that the Drosophila homeobox gene product Caudal functions as the innate immune transcription modulator that is responsible for the constitutive local expression of antimicrobial peptides cecropin and drosomycin in a tissue-specific manner. These results suggest that certain epithelial tissues have evolved a unique constitutive innate immune strategy by recruiting a developmental "master control" gene. [ABSTRACT FROM AUTHOR]

Examines the expression pattern of the early stage of secretion in nasal epithelial cells via the P2Y subtypes and their functions in normal human nasal epithelial cells. Effects of uridine-5'-triphosphate and ATPgammaS on mucin secretion and mucin gene expression; Expression pattern of P2Y receptors; Solutions for the chemicals; Cell cultures.

Objective --Non-steroidal anti-inflammatory drug-activated gene-1 (NAG-1) is a recently discovered transforming growth factor-beta superfamily cytokine. The localization and functions of NAG-1 have not been thoroughly studied. The aims of this study were to investigate its expression and localization in human nasal mucosa and also the change in NAG-1 expression as a function of mucociliary and squamous differentiation. Material and Methods --Anterior and middle portions of human inferior turbinate were used and immunohistochemical studies were performed using NAG-1 antibody. Passage-2 normal human nasal epithelial (NHNE) cell culture was performed for 14 days using the air-liquid interface method and the cells were divided into retinoic acid (RA)-sufficient and -deficient groups. Each group of cells was stained with hematoxylin-eosin to study the degree of differentiation. Western blot analysis for NAG-1 expression was performed in each group after 0, 7 and 14 days. Results --NAG-1 expression in mucociliated epithelium was noted in ciliated cells and serous acini, but was not found in goblet cells or mucous acini. In squamous epithelium, NAG-1 expression was weaker than that in mucociliated epithelium. In RA-sufficient culture, NHNE cells were differentiated into ciliated epithelium, but in RA-deficient culture, keratinizing squamous epithelium was noted. Western blot analysis showed that NAG-1 expression was significantly higher in RA-sufficient than -deficient culture (three-fold difference) and this expression was time-dependent. Conclusions --NAG-1 may be involved in differentiation and apoptotic processes of nasal epithelial cells. However, it is still unclear whether NAG-1 is an inducer or a byproduct of differentiation or apoptosis. The role of NAG-1 protein remains to be solved. [ABSTRACT FROM AUTHOR]

Objective—Extracellular uridine 5'-triphosphate (UTP) regulates a variety of biological functions in the airway epithelium, including chloride and fluid transport, mucociliary clearance and mucin secretion via the P2Y purinergic receptors. This study was undertaken to investigate which P2Y purinergic receptors are expressed in normal human middle ear epithelial (NHMEE) cells. We also determined the levels of mucin and lysozyme secretion and their mRNA expressions following stimulation with UTP in passage-2 cultured NHMEE cells. Material and methods—An immunoblotting assay was performed for quantitation of mucin and lysozyme proteins and RT-PCR for their gene levels after treatment with UTP was done in normal human middle ear epithelial cells. Results—Middle ear epithelial cells expressed P2Y[sub 1], P2Y[sub 2], P2Y[sub 6], P2Y[sub 11] and P2Y[sub1 2] receptors but not P2Y[sub 4] receptor. Apically applied UTP induced increased mucin and lysozyme secretion, as measured by dot blotting. In contrast, UTP did not enhance mucin and lysozyme mRNA expression until 72 h after treatment. Conclusion—This study suggests that UTP acts as a secretogogue on mucin and lysozyme secretion in NHMEE cells via the P[sub 2]Y[sub 2] and/or P[sub 2]Y[sub 6] receptor. [ABSTRACT FROM AUTHOR]

Objective --Diplopia after endoscopic sinus surgery (ESS) is rare but very serious. In this study, we investigated the characteristics, prognosis and treatment of diplopia occurring after ESS. Material and Methods --A retrospective analysis was carried out to investigate three patients with diplopia after ESS referred to us from other hospitals. Results --In one case, an improvement in ocular motility was seen after surgical treatment. In the other cases, no improvement was observed, despite surgical treatment. Conclusion --In order to prevent diplopia after ESS, the surgeon must possess a complete anatomical knowledge obtained by means of cadaveric dissection, the ability to carefully read preoperative CT scans and the necessary surgical experience. [ABSTRACT FROM AUTHOR]

The spatial and kinematic distribution of warm gas in and around the Coma Cluster is presented through observations of Lyα absorbers using background QSOs. Updates to the Lyα absorber distribution found in Yoon et al. for the Virgo Cluster are also presented. At 0.2–2.0Rvir of Coma we identify 14 Lyα absorbers () toward 5 sightlines and no Lyα absorbers along 3 sightlines within . For both Coma and Virgo, most Lyα absorbers are found outside the virial radius or beyond 1σv consistent with them largely representing the infalling intergalactic medium. The few exceptions in the central regions can be associated with galaxies. The Lyα absorbers avoid the hot ICM, consistent with the infalling gas being shock heated within the cluster. The massive dark matter halos of clusters do not show the increasing column density with decreasing impact parameter relationship found for the smaller mass galaxy halos. In addition, while the covering fraction within Rvir is lower for clusters than galaxies, beyond Rvir the covering fraction is somewhat higher for clusters. The velocity dispersion of the absorbers compared to the galaxies is higher for Coma, consistent with the absorbers tracing additional turbulent gas motions in the cluster outskirts. The results are overall consistent with cosmological simulations, with the covering fraction being high in the observations standing out as the primary discrepancy. [ABSTRACT FROM AUTHOR]

A correction to the article "Warm Gas in the Virgo Cluster. I. Distribution of Lyα Absorbers," which appeared in a 2012 issue is presented.

The Eastern Banded Structure (EBS) and Hydra I halo overdensities are very nearby (d ∼ 10 kpc) objects discovered in Sloan Digital Sky Survey (SDSS) data. Previous studies of the region have shown that EBS and Hydra I are spatially coincident, cold structures at the same distance, suggesting that Hydra I may be the EBS's progenitor. We combine new wide-field Dark Energy Camera (DECam) imaging and MMT/Hectochelle spectroscopic observations of Hydra I with SDSS archival spectroscopic observations to quantify Hydra I's present-day chemodynamical properties, and to infer whether it originated as a star cluster or dwarf galaxy. While previous work using shallow SDSS imaging assumed a standard old, metal-poor stellar population, our deeper DECam imaging reveals that Hydra I has a thin, well-defined main sequence turnoff of intermediate age (∼5–6 Gyr) and metallicity ([Fe/H] = −0.9 dex). We measure statistically significant spreads in both the iron and alpha-element abundances of dex and dex, respectively, and place upper limits on both the rotation and its proper motion. Hydra I's intermediate age and [Fe/H]—as well as its low [α/Fe], apparent [Fe/H] spread, and present-day low luminosity—suggest that its progenitor was a dwarf galaxy, which has subsequently lost more than 99.99% of its stellar mass. [ABSTRACT FROM AUTHOR]

Vitamin A and its metabolite retinoic acid (RA) are essential elements for normal lung development and the differentiation of lung epithelial cells. We previously showed that RA rapidly activated cyclic AMP response element-binding protein (CREB) in a nonclassical manner in normal human tracheobronchial epithelial (NHTBE) cells. In the present study, we further demonstrated that this nonclassical signaling of RA on the activation of CREB plays a critical role in regulating the expression of airway epithelial cell differentiation markers, the MUC2, MUC5AC, and MUC5B genes. We found that RA rapidly activates the protein kinase Cα isozyme and transmits the activation signal to CREB via the Raf/MEK/extracellular signal-regulated kinase/p90 ribosomal S6 kinase (RSK) pathway. Activated RSK translocated from the cytoplasm to the nucleus, where it phosphorylates CREB. Activated CREB then binds to a cis-acting replication element motif on the promoter (at nucleotides [nt] -878 to -871) of the MUC5AC gene. The depletion of CREB using small interfering RNA abolished not only the RA-induced MUC5AC but also RA-induced MUC2 and MUC5B. Taken together, our findings demonstrate that CREB activation via this nonclassical RA signaling pathway may play an important role in regulating the expression of mucin genes and mediating the early biological effects of RA during normal mucous differentiation in NHTBE cells. [ABSTRACT FROM AUTHOR]

The function of high-mobility group box 1 (HMGB1) varies according to its location. However, the translocation mechanism behind HMGB1 remains unclear. We hypothesize that type 2 helper T cell (Th2) cytokines are involved in the translocation of HMGB1 in the upper airway epithelium. We investigated the mechanism behind HMGB1 translocation using Th2 cytokine stimulation and examined the clinical significance of HMGB1 translocation in allergic rhinitis (AR). Cytoplasmic and extracellular HMGB1 were increased in AR. Inhibiting HMGB1 translocation with glycyrrhizic acid (GA) decreased the level of antigen-specific immunoglobulin E (IgE), the degree of Periodic Acid-Schiff (PAS), and Sirius Red staining in the murine model. The in vivo reactive oxygen species (ROS) level in the nasal mucosa was higher in the mice with AR than in the controls. Th2 cytokine-induced up-regulation of the ROS and translocation of HMGB1 by Th2 cytokines was dependent on the generated ROS. The ROS level also increased in the murine model. We suggest that the Th2 cytokine-dual oxidase (DUOX)2-ROS-HMGB1 translocation axis is important in AR pathogenesis. [ABSTRACT FROM AUTHOR]

Accumulating evidence suggests that two chronic respiratory diseases, nontuberculous mycobacterium (NTM)-pulmonary disease (PD) and allergic asthma, are frequently present together and that they likely influence the disease development and progression of each other. However, their precise interactions regarding the pathogenesis of comorbid diseases versus that of individual diseases are not well understood. In this study, comorbid diseases (i.e., Mycobacteria avium (Mav) pulmonary infection (PI) (Mav-PI) and ovalbumin-induced allergic asthma) were established in mice in different orders and at different time periods. Individual disease-specific characteristics, including alterations in immune cell populations and antigen-specific immune responses, were analyzed and compared. To assess Mav-PI pathogenesis, lung inflammation and bacterial burden levels were also determined. Allergic asthma induction in the presence of Mav-PI markedly aggravated Mav-PI pathogenesis by increasing the bacterial burden and the severity of lung inflammation. Interestingly, the general outcome of allergic asthma with goblet cell hyperplasia was alleviated at a chronic stage in the comorbid mouse model. Overall, the increase in the number of Mav CFUs was inversely correlated with the Mav-specific Th17 response, as confirmed by comparing BALB/c and C57BL/6J mice. Overall, the pathogenesis of existing Mav-PI is more severely affected by allergen exposure than vice versa. This Mav-PI exacerbation is associated with disruption of Mav-specific Th17 responses. This study provides the first evidence that the Mav-specific Th17 response plays an important role in the control of Mav pathogenesis in the presence of allergic asthma, indicating that targeting the Th17 response has therapeutic potential for NTM-PD accompanied by allergic asthma. [ABSTRACT FROM AUTHOR]

Vitamin A deficiency (VAD) alters the phenotype of airway epithelium and attenuates the epithelial defense system, and many studies have reported the association of VAD with respiratory disease. In this study, we investigated changes in submucosal glands (SMG) in a mouse model of VAD. C57BL/6 mice were fed a vitamin A-devoid diet and the others were fed a control diet (1.2 mg retinol/kg). The areas of serous and mucous cells of SMG were measured in 4-, 8-, and 20-wk-old male mice. The volume and lysozyme concentration of glandular secretions were also measured. The 2 groups did not differ in body weight or general morbidity at 3-10 wk of age, although serum retinol concentrations were greater in the control mice than in the VAD mice after 4 wk. Upon histological evaluation, we found that the areal ratio of serous cells: total SMG cells was significantly lower after 8 wk in the VAD mice compared with the control mice, although the total area of SMG did not differ between groups throughout the 20-wk experiment. The number of secretory bubbles did not differ between the groups, but total secretion volume was reduced by 35% in 8-wk-old VAD mice compared with controls. Furthermore, the concentration of lysozyme in secretions from 8-wk-old VAD mice was also less than in controls, compounding the effect of diminished secretion volume. In this study, we found serous cell hypotrophy/hypoplasia and dysfunction in VAD mice, which may contribute to the susceptibility to airway infection linked to VAD. [ABSTRACT FROM AUTHOR]

The symbiotic microbiota profoundly affect many aspects of host physiology; however, the molecular mechanisms underlying host-microbe cross-talk are largely unknown. Here, we show that the pyrroloquinotine quinone-dependent alcohol dehydrogenase (PQQ-ADH) activity of a commensal bacterium, Acetobacter pomorum, modulates insulin/insulin-like growth factor signaling (IIS) in Drosophilo to regulate host homeostatic programs controlling developmental rate, body size, energy metabolism, and intestinal stem cell activity. Germ-free animals monoassociated with PQQ-ADH mutant bacteria displayed severe deregulation of developmental and metabolic homeostasis. Importantly, these defects were reversed by enhancing host IIS or by supplementing the diet with acetic acid, the metabolic product of PQQ-ADH. [ABSTRACT FROM AUTHOR]

Mucus hypersecretion is a prominent feature of respiratory diseases, and MUC5B is a major airway mucin. Mucin gene expression can be affected by inflammatory mediators, including prostaglandin (PG) D(2,) an inflammatory mediator synthesized by hematopoietic PGD synthase (H-PGDS). PGD2 binds to either d-prostanoid receptor (DP1) or chemoattractant receptor homologous molecule expressed on T-helper type 2 cells (CRTH2). We investigated the mechanisms by which PGD2 induces MUC5B gene expression in airway epithelial cells. Western blot analysis showed that H-PGDS was highly expressed in nasal polyps. Similar results were obtained for PGD2 expression. In addition, we could clearly detect the expressions of both H-PGDS and DP1 in nasal epithelial cells but not CRTH2. We demonstrated that PGD(2) increased MUC5B gene expression in normal human nasal epithelial cells as well as in NCI-H292 cells in vitro. S5751, a DP1 antagonist, inhibited PGD2-induced MUC5B expression, whereas a CRTH2 antagonist (OC0459) did not. These data suggest that PGD2 induced MUC5B expression via DP1. Pretreatment with extracellular signal-regulated kinase (ERK) inhibitor (PD98059) blocked both PGD2-induced ERK mitogen-activated protein kinase (MAPK) activation and MUC5B expression. Proximity ligation assays showed direct interaction between RSK1 and cAMP response element-binding protein (CREB). Stimulation with PGD2 caused an increase in intracellular cAMP levels, whereas intracellular Ca(2+) did not have such an effect. PGD2-induced MUC5B mRNA levels were regulated by CREB via direct interaction with two cAMP-response element sites (-921/-914 and -900/-893). Finally, we demonstrated that PGD2 can induce MUC5B overproduction via ERK MAPK/RSK1/CREB signaling and that DP1 receptor may have suppressive effects in controlling MUC5B overproduction in the airway. [ABSTRACT FROM AUTHOR]

Exogenous ATP activates purinoreceptors on the cell surface that regulate diverse cellular functions, including mucous cell secretion in the respiratory epithelium. In this study, ATP increased MUC5AC mRNA in primary human nasal epithelial cells and in NCI-H292 pulmonary adenocarcinoma cells in vitro. ATP-induced MUC5AC mRNA was mediated by phospholipase Cβ3.Adominant-negative mutation in the PDZ binding domain of PLCβ3 inhibited ATP-induced MUC5AC gene expression. ATP sequentially activated the phosphorylation of Akt, ERK1/2, p38, RSK1, and cAMP-responding element-binding protein (CREB) in a protein kinase C-independent manner. ATP-induced MUC5AC mRNA levels were regulated by CREB via direct interaction with c-Ets1 on the MUC5AC gene promoter (located -938 to -930). Effects of CREB and c-Ets1 were additive. Inhibition of either CREB or c-Ets1 inhibited ATP-induced MUC5AC gene expression. Stimulation with ATP caused the direct binding of CREB and c-Ets1 to the MUC5AC promoter, increasing the phosphorylation of c-Ets1. Chromatin immunoprecipitation assays demonstrated that in the presence of ATP, both c-Ets1 and CREB bound to the MUC5AC promoter. The effects of exogenous ATP on MUC5AC gene expression are mediated by a complex regulatory cascade controlling interactions between CREB and c-Ets1 that bind to a promoter element in the MUC5AC gene enhancing MUC5AC gene transcription. ATP-dependent activation of MUC5AC gene expression via CREB-c-Ets1 may contribute to mucous cell hypersecretion associated with common respiratory disorders. [ABSTRACT FROM AUTHOR]

MUC8 gene expression is overexpressed in nasal polyp epithelium and is also increased by treatment with inflammatory mediators in nasal epithelial cells. These data suggest that MUC8 may be one of important mucin genes expressed in human airway. However, the mechanisms of various inflammatory mediator-induced MUC8 gene expression in normal nasal epithelial cells remain unclear. We examined the mechanism by which prostaglandin E2 (PGE2), an arachidonic acid metabolite, increases MUC8 gene expression levels. Here, we show that ERK mitogen-activated protein kinase is essential for PGE2-induced MUC8 gene expression in normal human nasal epithelial cells and that p90 ribosomal S 6 protein kinase 1 (RSK1) mediates the PGE2-induced phosphorylation of cAMP-response element binding protein. Our results also indicate that cAMP-response element at the -803 region of the MUC8 promoter is an important site of PGE2-induced MUC8 gene expression. In conclusion, this study gives insights into the molecular mechanism of PGE2-induced MUC8 gene expression in human airway epithelial cells. [ABSTRACT FROM AUTHOR]

Increasing evidence suggests that P2 receptors (P2Rs) in airway epithelial cells perform critical functions in auto- or paracrine regulation of fluid and mucus secretion. In the present study, we characterized the effects of P2R stimulation on Na+-K+-2CI- cotransporter (NKCC) activity in normal human nasal epithelial (NHNE) cells. [Ca2+]i and pHi were measured in primary cultures of NHNE cells using a double perfusion chamber, which enabled us to analyze membrane-specific transporter activities. NKCC activities were estimated by the pHi reduction due to Na+-dependent and bumetanide-sensitive intracellular uptake of NH4+→ NKCC activities were observed in the basolateral membrane, but not in the luminal membrane, of NHNE cells. Interestingly, P2Rs were expressed in both membranes, and the stimulation of either luminal or basolateral P2R increased NKCC activity. Blockades of luminal Cl- channels, basolateral K+ channels, or protein kinase C did not affect the activation of NKCC by basolateral P2R stimulation. The effects of luminal P2R stimulation were partially reduced by Cl- channel blockers. However, chelation of intracellular Ca2+ by 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA) treatment completely blocked the stimulatory effects of luminal and basolateral P2Rs on NKCC. In addition, increasing [Ca2+]i by treatment with ionomycin-stimulated NKCC activity. These results provide evidence that stimulation of P2Rs directly activates basolateral NKCC by Ca2+-dependent pathways in NHNE cells, which is an important aspect of the purinergic regulation of ion and fluid secretions in human airway epithelia under physiologic and pathologic conditions. [ABSTRACT FROM AUTHOR]

Mucins are the major components of the mucus layer that covers and protects the respiratory, digestive, and reproductive tracts. Our previous studies showed that MUC8 gene expression was overexpressed in vivo polyp epithelium in chronic sinusitis and was also increased by treatment with inflammatory mediators in an in vitro culture condition. However, the mechanisms by which the inflammatory mediators-induced MUC8 gene expression in normal nasal epithelial cells evolved remain unclear. We examined the mechanism by which the important proinflammatory mediator, interleukin (IL)-1β, increases MUC8 gene expression levels. We found that pharmacologic and genetic inhibition of ERK MAPK pathway abolished IL-1β-induced MUC8 gene expression in normal human nasal epithelial cells. Moreover, the overexpression of wide-type or of the dominant-negative mutant of p90 ribosomal S6 protein kinase 1 (RSK1) enhanced or suppressed, respectively, IL-1β-induced MUC8 gene expression. RSK1 was found to directly phosphorylate cAMP-response element-binding protein (CREB), and this event led to the stimulation of subsequent CRE-mediated gene transcription. In conclusion, IL-1β was found to induce MUC8 gene expression via a sequential ERK/RSK1/CREB pathway in human airway epithelial cells. [ABSTRACT FROM AUTHOR]

Studies the mechanisms by which interleukin-1 beta and tumor necrosis factor induce MUC5AC gene expression in normal nasal epithelial cells. Genetic or pharmacologic inhibition of p38 mitogen-activated protein kinase pathway; Activation of mitogen- and stress-activated protein kinase 1 and cyclic adenosine monophosphate-response element-binding protein.