A 30-year old man was admitted to our hospital with cough, slight fever, and dyspnea that he had developed several hours after inhaling the fumes produced from a Teflon-coated pan, after evaporation of the water in the pan. Chest radiography revealed diffuse infiltrations, and a computed tomography (CT) scan revealed patchy interstitial shadows in both lungs. In pulmonary function tests, the diffusing capacity of the lungs showed a moderate decrease. Leukocytosis and slight hypoxemia were observed. The patient recovered clinically in a few days without any specific treatment. We speculated that the pulmonary problems in this patient may have been induced by the products of thermal degradation of Teflon that were present in the fumes. When Teflon is heated, the fumes generated cause an influenza like syndrome (polymer fume fever) or cause severe toxic effects such as pulmonary edema, pneumonitis, and death in the exposed individual.

The human respiratory tract is constantly exposed to polycyclic aromatic hydrocarbons (PAHs) through inhalation of atmospheric pollutants. We examined the effects of three PAHs (benzo[a]pyrene, anthracene, and fluoranthene) on the airway ion transport, which is essential for lung defense and normal airway function, using human airway epithelia (Calu-3). These three PAHs had no significant effect on the basal short-circuit current (Isc). However, fluoranthene (1–100 μM) applied in the apical compartment potentiated Isc in response to cAMP-related agents (isoproterenol, forskolin, and 8-bromo-cAMP). The effects of fluoranthene were unaffected by ellipticine, a PAH receptor antagonist. Estimation of the anionic composition of Isc revealed that isoproterenol increased both \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{HCO}_{3}^{-}\) \end{document} and Cl– transport in the control, whereas it potentiated only Cl– transport in the presence of fluoranthene. The fluoranthene-induced modulations of these anion transporters were counteracted by charybdotoxin (ChTx, a hIK-1 channel blocker). Fluoranthene gradually augmented the ChTx-sensitive K+ current (IK) across the basolateral membrane, accompanied by a sustained increase in the cytosolic Ca2+ concentration ([Ca2+]i). In the presence of fluoranthene, however, a much larger hIK-1-dependent IK was identified by the application of 8-bromo-cAMP without concomitant elevation of [Ca2+]i. These results suggest that fluoranthene switches from cAMP-dependent \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{HCO}_{3}^{-}\) \end{document} secretion to Cl– secretion through the hIK-1 channel, whose sensitivity to protein kinase A may be up-regulated by the sustained [Ca2+]i elevation produced by this chemical.

Airway mucociliary clearance is subject to the autocrine/paracrine regulation of extracellular nucleotides released from the airway epithelial cells. The present study was performed in pursuit of effective modulators of ATP release under physiologic conditions in polarized human airway epithelial cells (Calu-3). Neither isoproterenol, forskolin, nor ionomycin augmented extracellular ATP release detected by luciferase assay. However, direct activation of the human intermediate conductance, Ca(2+)-activated K(+) channel (hIK-1) by 1-ethyl-2-benzimdazolinone (1-EBIO, 1 mM) and chlorzoxazone (CZ, 1 mM) increased ATP release predominantly in the apical compartment. Measurement of fluo-3 signals revealed that 1-EBIO- and CZ-stimulated cytosolic Ca(2+) mobilization was suppressed by the presence of MRS-2179, a specific P2Y(1) receptor antagonist. The hIK-1-mediated ATP release was inhibited by a hIK-1 blocker (charybdotoxin), and an Na(+)-K(+)-2Cl(-) cotransport blocker (bumetanide) without interruption by GdCl(3), an inhibitor of stretch-activated nonselective cation (SA) channels, or glybenclamide, a blocker of the cystic fibrosis transmembrane conductance regulator (CFTR). These results suggest that a cell volume decrease via the hIK-1-mediated KCl loss and the resultant induction of a regulatory volume increase via the Na(+)-K(+)-2Cl(-) transporter may trigger release of ATP, which causes P2Y(1)-mediated Ca(2+) mobilization, through mechanisms unrelated to the CFTR and SA channels.

Endogeneous and exogeneous amine-containing substances possess pneumophilic properties. Among them, tricyclic amphiphilic amine drugs like neuroleptics intensively accumulate in the lung cell membrane and occasionally cause severe respiratory disorders. In the present study, we examined the bioelectric toxicity of chlorpromazine (CPZ), a commonly used neuroleptic, in human lung epithelial cells. CPZ concentration-dependently inhibited the isoproterenol (ISO)-generated short-circuit current (I(sc)) sensitive to a nonselective K(+) channel blocker, clotrimazole (30 microM), but insensitive to a selective Ca(2+)-activated K(+) (K(Ca)) channel blocker, charybdotoxin (ChTx, 100 nM). The effects of apical CPZ on the ISO-induced responses were greater than those of basolateral CPZ. Forskolin- and 8-bromo-cyclic AMP-induced I(sc) were partially prevented by CPZ. Nystatin permeabilization of the monolayers revealed that CPZ attenuated the basolateral K(+) current elicited by ISO more than that elicited by forskolin and that the apical Cl(-) current elicited by forskolin was instead potentiated by CPZ, although it inhibited the ISO-induced Cl(-) current. 1-Ethyl-2-benzimdazolinone (1-EBIO, a K(Ca) channel opener, 500 microM)- and ionomycin (Ca(2+) ionophore, 1 microM)-evoked Cl(-) secretions were also sensitive to CPZ. These results indicate that CPZ inhibits transepithelial Cl(-) transport, affecting at least two different targets: the beta-adrenergic receptor and the basolateral K(+) channels (especially the K(Ca) channel). Electrostatic interactions at the inner surface of the membrane between the protonated amines of CPZ and negatively charged portions of the plasma membrane may be involved in the mechanisms.

There has been growing concern about the potential threat of hormone-disrupting chemicals like bisphenol A to various aspects of animal and human health. We studied the effects of bisphenol A on the Cl(-) secretion in human airway epithelial Calu-3 cells. Pretreatment with bisphenol A (IC(50) = 60 microM, for 30 min) prevented isoproterenol (10 nM)-generated short-circuit current (I(sc)) more potently than 17beta-estradiol or tamoxifen (IC(50) = 1 mM). 5'-Nitro-2-(3-phenylpropylamino) benzoate-sensitive apical conductance potentiated by isoproterenol was not affected by the pretreatment with either of these estrogenic compounds. The effects of bisphenol A were simulated in I(sc) responses to forskolin (10 microM) and 8-bromo-cAMP (1 mM). Nystatin permeabilization of Calu-3 monolayers revealed that bisphenol A attenuated 8-bromo-cAMP-induced basolateral K+ current, which is sensitive to clotrimazole (30 microM) and insensitive to charybdotoxin (100 nM), without affecting the apical Cl(-) current. Bisphenol A, but neither 17beta-estradiol nor tamoxifen, interrupted the charybdotoxin-sensitive component of I(sc) stimulated by 1-ethyl-2-benzimidazolinone (1-EBIO; 500 microM). The inhibitory effects of bisphenol A on these Cl(-) secretory stimuli were remarkable when applied to the apical rather than the basolateral membrane. Alternatively, long-term incubation of bisphenol A (1 microM; 12-72 h) had no discernible effect on isoproterenol- and 1-EBIO-induced Cl(-) secretion. These findings indicate that short-term exposure to bisphenol A attenuates transepithelial Cl(-) secretion through inhibition of both cAMP- and Ca(2+)-activated K+ channels on the basolateral membrane, interacting from the cytosolic surface in Calu-3 cells.

The present study concerns previously unreported effects of the antibiotic minocycline on the transepithelial Cl− transport in Calu-3 cells, which display electrophysiological properties consistent with human airway serous cells. Basolateral 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (DIDS, 200 μM) augmented Cl− secretion, which was detected as a 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB, 100 μM, a Cl− channel blocker)-sensitive short-circuit current (Isc). The DIDS-induced Isc was composed of Ca2+-activated K+ (KCa) channel-dependent and -independent components. The former was selectively inhibited by 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid tetra(acetoxymethyl)ester (BAPTA/AM, 10 μM), charybdotoxin (ChTx, 100 nM), clotrimazole (10 μM), basolateral Ca2+ removal, and basolateral minocycline (IC50 = 20 μM). The latter was attenuated by basolateral BaCl (5 mM). In contrast, forskolin (10 μM)-induced Isc, which is insensitive to BAPTA/AM and ChTx, was unaffected by minocycline (100 μM). ATP-induced Isc was partially inhibited by basolateral but not by apical minocycline. Isc due to basolateral application of ionomycin (1 μM) was markedly suppressed by NPPB and basolateral Ca2+ removal. These inhibitory effects were mimicked by minocycline applied only from the basolateral side of the monolayer. In the basolateral absence of Ca2+, 1-ethyl-2-benzimdazolinone (500 μM), a KCa channel opener, generated a sustained Isc sensitive to ChTx. Minocycline had no significant effect on the ChTx-sensitive component of the Isc. It is concluded that minocycline inhibits KCa channel-dependent Cl− secretion via a blockade of Ca2+ influx across the basolateral membrane from the extracellular side.

Polyene antifungal antibiotics like nystatin form monovalent cation pores on the plasma membrane that perturb the intracellular electrolyte milieu, resulting in cell damage. In the present study, we investigated the effects of tetracyclines (minocycline and tetracycline) on ion transporters disrupted by nystatin in cultured human airway Calu-3 cells. Apical application of nystatin (50 microM) on a monolayer of the cells stimulated Na(+)-K(+) pump activity as estimated by ouabain (1 mM)-sensitive short-circuit current (I(sc)). The nystatin-potentiated I(sc) was inhibited by minocycline (IC(50) = 25 microM) or tetracycline (IC(50) = 150 microM) applied only from the apical (nystatin-treated) side. Nystatin increased monolayer conductance that was reversed by the application of tetracyclines. In contrast, ouabain potentiated the nystatin-induced change in the conductance. Further, Na(+)-glucose transport affected by nystatin was also normalized by tetracyclines from the nystatin-treated side of the membrane. These data suggest that tetracyclines may lower the cell permeability potentiated by nystatin, protecting cells against damage.