RESUMEN
CFTR (cystic fibrosis transmembrane conductance regulator) is a tightly regulated anion channel that mediates chloride and bicarbonate conductance in many epithelia and in other tissues, but whether its regulation varies depending on the cell type has not been investigated. Epithelial CFTR expression is highest in rare cells called ionocytes. We studied CFTR regulation in control and ionocyte-enriched cultures by transducing bronchial basal cells with adenoviruses that encode only eGFP or FOXI1 (forkhead box I1) + eGFP as separate polypeptides. FOXI1 dramatically increased the number of transcripts for ionocyte markers ASCL3 (Achaete-Scute Family BHLH Transcription Factor 3), BSND, ATP6V1G3, ATP6V0D2, KCNMA1, and CFTR without altering those for secretory (SCGB1A1), basal (KRT5, KRT6, TP63), goblet (MUC5AC), or ciliated (FOXJ1) cells. The number of cells displaying strong FOXI1 expression was increased 7-fold, and there was no evidence for a broad increase in background immunofluorescence. Total CFTR mRNA and protein levels increased 10-fold and 2.5-fold, respectively. Ionocyte-enriched cultures displayed elevated basal current, increased adenylyl cyclase 5 expression, and tonic suppression of CFTR activity by the phosphodiesterase PDE1C, which has not been shown previously to regulate CFTR activity. The results indicate that CFTR regulation depends on cell type and identifies PDE1C as a potential target for therapeutics that aim to increase CFTR function specifically in ionocytes.
Asunto(s)
Regulador de Conductancia de Transmembrana de Fibrosis Quística , Células Epiteliales , Bronquios/metabolismo , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Células Epiteliales/metabolismo , Epitelio/metabolismo , Transporte Iónico , HumanosRESUMEN
Chronic obstructive pulmonary disease (COPD) is a leading cause of death and cigarette smoke is the main risk factor. Detecting its earliest stages and preventing a decline in lung function are key goals. The pathogenesis of COPD is complex but has some similarities to cystic fibrosis (CF), a disease caused by mutations in the cftr gene. CF leads to chronic inflammation, abnormal mucus, and cycles of infection. Cigarette smoke exposure also causes CFTR dysfunction, and it is probably not a coincidence that inflammation, mucus obstruction, and infections are also characteristics of COPD, although the exacerbations can be quite different. We review here the acute effects of cigarette smoke on CFTR function and its potential role in COPD. Understanding CFTR regulation by cigarette smoke may identify novel drug targets and facilitate the development of therapeutics that reduce the progression and severity of COPD.
Asunto(s)
Fumar Cigarrillos , Fibrosis Quística , Enfermedad Pulmonar Obstructiva Crónica , Humanos , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Fumar Cigarrillos/efectos adversos , Enfermedad Pulmonar Obstructiva Crónica/genética , Fibrosis Quística/genética , Nicotiana , InflamaciónRESUMEN
Membrane proteins often cluster in nanoscale membrane domains (lipid rafts) that coalesce into ceramide-rich platforms during cell stress, however the clustering mechanisms remain uncertain. The cystic fibrosis transmembrane conductance regulator (CFTR), which is mutated in cystic fibrosis (CF), forms clusters that are cholesterol dependent and become incorporated into long-lived platforms during hormonal stimulation. We report here that clustering does not involve known tethering interactions of CFTR with PDZ domain proteins, filamin A or the actin cytoskeleton. It also does not require CFTR palmitoylation but is critically dependent on membrane lipid order and is induced by detergents that increase the phase separation of membrane lipids. Clustering and integration of CFTR into ceramide-rich platforms are abolished by the disease mutations F508del and S13F and rescued by the CFTR modulators elexacaftor plus tezacaftor. These results indicate CF therapeutics that correct mutant protein folding restore both trafficking and normal lipid interactions in the plasma membrane. This article has an associated First Person interview with the first author of the paper.
Asunto(s)
Fibrosis Quística , Aminofenoles/farmacología , Benzodioxoles/farmacología , Ceramidas , Análisis por Conglomerados , Fibrosis Quística/tratamiento farmacológico , Fibrosis Quística/genética , Fibrosis Quística/metabolismo , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Humanos , Lípidos , Mutación/genéticaRESUMEN
BACKGROUND/AIMS: Cystic fibrosis transmembrane conductance regulator (CFTR), the anion channel that is defective in cystic fibrosis (CF), is phosphorylated and activated by cAMP-dependent protein kinase (PKA). cAMP levels are downregulated by a large family of phosphodiesterases that have variable expression in different cell types. We have previously observed high levels of PDE8A expression in well-differentiated primary human bronchial epithelial (pHBE) cells and thus aimed to assess whether it played a role in cAMP-dependent regulation of CFTR activity. METHODS: We assessed the effect of the selective PDE8 inhibitor PF-04957325 (PF) on intracellular cAMP levels ([cAMP]i) in well differentiated pHBE cells from non-CF or CF donors and also in CFBE41o- cells that stably express wild-type CFTR (CFBE41o- WT) using ELISA and FRET-FLIM microscopy. CFTR channel function was also measured using electrophysiological recordings from pHBE and CFBE41o- WT cells mounted in Ussing Chambers. RESULTS: PDE8 inhibition elevated [cAMP]i in well-differentiated pHBE cells and stimulated wild-type CFTR-dependent ion transport under basal conditions or after cells had been pre-stimulated with physiological cAMP-elevating agents. The response to PDE8 inhibition was larger than to PDE3 or PDE5 inhibition but smaller and synergistic with that elicited by PDE4 inhibition. CRISPR Cas9-mediated knockdown of PDE8A enhanced CFTR gene and protein expression yet reduced the effect of PDE8 inhibition. Acute pharmacological inhibition PDE8 increased CFTR activity in CF pHBE cells (F508del/F508del and F508del/R117H-5T) treated with clinically-approved CFTR modulators. CONCLUSION: These results provide the first evidence that PDE8A regulates CFTR and identifies PDE8A as a potential target for adjunct therapies to treat CF.
Asunto(s)
3',5'-AMP Cíclico Fosfodiesterasas/metabolismo , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Fibrosis Quística/metabolismo , Células Epiteliales/metabolismo , Mucosa Respiratoria/metabolismo , 3',5'-AMP Cíclico Fosfodiesterasas/genética , Animales , Línea Celular , Cricetinae , AMP Cíclico/genética , AMP Cíclico/metabolismo , Fibrosis Quística/genética , Fibrosis Quística/patología , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Células Epiteliales/patología , Humanos , Mucosa Respiratoria/patologíaRESUMEN
Cystic Fibrosis (CF) lung disease results from mutations in the CFTR anion channel that reduce anion and fluid secretion by airway epithelia. Impaired secretion compromises airway innate defence mechanisms and leads to bacterial colonization, excessive inflammation and tissue damage; thus, restoration of CFTR function is the goal of many CF therapies. CFTR channels are activated by cyclic nucleotide-dependent protein kinases. The second messengers 3'5'-cAMP and 3'5'-cGMP are hydrolysed by a large family of cyclic nucleotide phosphodiesterases that provide subcellular spatial and temporal control of cyclic nucleotide-dependent signalling. Selective inhibition of these enzymes elevates cyclic nucleotide levels, leading to activation of CFTR and other downstream effectors. Here we examine members of the PDE family that are likely to regulate CFTR-dependent ion and fluid secretion in the airways and discuss other actions of PDE inhibitors that can influence cyclic nucleotide-regulated mucociliary transport, inflammation and bronchodilation. Finally, we review PDE inhibitors and the potential benefits they could provide as CF therapeutics.
Asunto(s)
Fibrosis Quística , Nucleótidos Cíclicos , Inhibidores de Fosfodiesterasa , Fibrosis Quística/tratamiento farmacológico , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Humanos , Inflamación , Nucleótidos Cíclicos/farmacología , Inhibidores de Fosfodiesterasa/farmacologíaRESUMEN
Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel that impair airway salt and fluid secretion. Excessive release of proinflammatory cytokines and chemokines by CF bronchial epithelium during airway infection leads to chronic inflammation and a slow decline in lung function; thus, there is much interest in finding safe and effective treatments that reduce inflammation in CF. We showed previously that the cyclic nucleotide phosphodiesterase (PDE) inhibitor ensifentrine (RPL554; Verona Pharma) stimulates the channel function of CFTR mutants with abnormal gating and also those with defective trafficking that are partially rescued using a clinically approved corrector drug. PDE inhibitors also have known anti-inflammatory effects; therefore, we examined whether ensifentrine alters the production of proinflammatory cytokines in CF bronchial epithelial cells. Ensifentrine reduced the production of monocyte chemoattractant protein-1 and granulocyte monocyte colony-stimulating factor (GM-CSF) during challenge with interleukin-1ß Comparing the effect of ensifentrine with milrinone and roflumilast, selective PDE3 and PDE4 inhibitors, respectively, demonstrated that the anti-inflammatory effect of ensifentrine was mainly due to inhibition of PDE4. Beneficial modulation of GM-CSF was further enhanced when ensifentrine was combined with low concentrations of the ß 2-adrenergic agonist isoproterenol or the corticosteroid dexamethasone. The results indicate that ensifentrine may have beneficial anti-inflammatory effects in CF airways particularly when used in combination with ß 2-adrenergic agonists or corticosteroids. SIGNIFICANCE STATEMENT: Airway inflammation that is disproportionate to the burden of chronic airway infection causes much of the pathology in the cystic fibrosis (CF) lung. We show here that ensifentrine beneficially modulates the release of proinflammatory factors in well differentiated CF bronchial epithelial cells that is further enhanced when combined with ß2-adrenergic agonists or low-concentration corticosteroids. The results encourage further clinical testing of ensifentrine, alone and in combination with ß2-adrenergic agonists or low-concentration corticosteroids, as a novel anti-inflammatory therapy for CF.
Asunto(s)
Bronquios/citología , Diferenciación Celular/efectos de los fármacos , Células Epiteliales/citología , Células Epiteliales/efectos de los fármacos , Mediadores de Inflamación/metabolismo , Isoquinolinas/farmacología , Inhibidores de Fosfodiesterasa 4/farmacología , Pirimidinonas/farmacología , Línea Celular , Quimiocina CCL2/biosíntesis , AMP Cíclico/metabolismo , Dexametasona/farmacología , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Células Epiteliales/metabolismo , Factor Estimulante de Colonias de Granulocitos y Macrófagos/biosíntesis , Humanos , Interleucina-8/biosíntesis , Espacio Intracelular/efectos de los fármacos , Espacio Intracelular/metabolismo , Regulación hacia Arriba/efectos de los fármacosRESUMEN
Despite progress in developing pharmacotherapies to rescue F508del-CFTR, the most prevalent Cystic Fibrosis (CF)-causing mutation, individuals homozygous for this mutation still face several disease-related symptoms. Thus, more potent compound combinations are still needed. Here, we investigated the mechanism of action (MoA) of RDR01752, a novel F508del-CFTR trafficking corrector. F508del-CFTR correction by RDR01752 was assessed by biochemical, immunofluorescence microscopy and functional assays in cell lines and in intestinal organoids. To determine the MoA of RDR01752, we assessed its additive effects to those of genetic revertants of F508del-CFTR, the FDA-approved corrector drugs VX-809 and VX-661, and low temperature. Our data demonstrated that RDR01752 rescues F508del-CFTR processing and plasma membrane (PM) expression to similar levels of VX-809 in cell lines, although RDR01752 produced lower functional rescue. However, in functional assays using intestinal organoids (F508del/F508del), RDR01752, VX-809 and VX-661 had similar efficacy. RDR01752 demonstrated additivity to revertants 4RK and G550E, but not to R1070W, as previously shown for VX-809. RDR01752 was also additive to low temperature. Co-treatment of RDR01752 and VX-809 did not increase F508del-CFTR PM expression and function compared to each corrector alone. The lack of additivity of RDR01752 with the genetic revertant R1070W suggests that this compound has the same effect as the insertion of tryptophan at 1070, i.e., filling the pocket at the NBD1:ICL4 interface in F508del-CFTR, similarly to VX-809. Combination of RDR01752 with correctors mimicking the rescue by revertants G550E or 4RK could thus maximize rescue of F508del-CFTR.
Asunto(s)
Aminopiridinas/farmacología , Benzodioxoles/farmacología , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Fibrosis Quística/tratamiento farmacológico , Fibrosis Quística/genética , Indoles/farmacología , Bronquios/efectos de los fármacos , Bronquios/metabolismo , Línea Celular , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Descubrimiento de Drogas , Humanos , Mutación , Organoides/efectos de los fármacos , Organoides/metabolismo , Transporte de Proteínas/efectos de los fármacos , Transporte de Proteínas/genéticaRESUMEN
Over 2,000 mutations have been reported in the cystic fibrosis transmembrane conductance regulator (cftr) gene, many of which cause disease but are rare and have no effective treatment. Thus, there is an unmet need for new, mutation-agnostic therapies for cystic fibrosis (CF). Phosphodiesterase (PDE) inhibitors are one such class of therapeutics that have been shown to elevate intracellular cAMP levels and stimulate CFTR-dependent anion secretion in human airway epithelia; however, the number of people with CF that could be helped by PDE inhibitors remains to be determined. Here we used Fisher rat thyroid (FRT) cells stably transduced with rare human CFTR mutants and studied their responsiveness to the dual phosphodiesterase 3/4 inhibitor RPL554 (Verona Pharma). Through its inhibitory effect on PDE4D, we find that RPL554 can elevate intracellular cAMP leading to a potentiation of forskolin-stimulated current mediated by R334W, T338I, G551D, and S549R mutants of CFTR when used alone or in combination with CFTR modulators. We also were able to reproduce these effects of RPL554 on G551D-CFTR when it was expressed in primary human bronchial epithelial cells, indicating that RPL554 would have stimulatory effects on rare CFTR mutants in human airways and validating FRT cells as a model for PDE inhibitor studies. Furthermore, we provide biochemical evidence that VX-809 causes surprisingly robust correction of several class III and IV CFTR mutants. Together, our findings further support the therapeutic potential of RPL554 for patients with CF with class III/IV mutations and emphasize the potential of PDEs as potential drug targets that could benefit patients with CF.
Asunto(s)
AMP Cíclico/metabolismo , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Isoquinolinas/farmacología , Inhibidores de Fosfodiesterasa 3/farmacología , Inhibidores de Fosfodiesterasa 4/farmacología , Pirimidinonas/farmacología , Células Epiteliales Tiroideas/efectos de los fármacos , Aminopiridinas/farmacología , Animales , Benzodioxoles/farmacología , Bronquios/citología , Bronquios/efectos de los fármacos , Bronquios/metabolismo , Línea Celular , Colforsina/farmacología , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 3/genética , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 3/metabolismo , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 4/genética , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 4/metabolismo , Regulador de Conductancia de Transmembrana de Fibrosis Quística/agonistas , Regulador de Conductancia de Transmembrana de Fibrosis Quística/clasificación , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Humanos , Mutación , Cultivo Primario de Células , Ratas , Ratas Endogámicas F344 , Células Epiteliales Tiroideas/citología , Células Epiteliales Tiroideas/metabolismo , TransgenesRESUMEN
To study respiratory diseases, in vitro airway epithelial models are commonly implemented by culturing airway cells on a porous surface at an air-liquid interface (ALI). However, these surfaces are often supraphysiologically stiff, which is known to affect the organization, maturation, and responses of cells to potential therapies in other biological culture models. While it is possible to culture cells on soft hydrogel substrates at an air-liquid interface, these techniques are challenging to implement particularly in high-throughput applications which require robust and repetitive material handling procedures. To address these two limitations and characterize epithelial cultures on substrates of varying stiffness at the ALI, we developed a novel "lung-on-a-boat", in which stiffness-tuneable hydrogels are integrated into the bottoms of polymeric microstructures, which normally float at the air-liquid interface. An embedded magnetic material can be used to sink the boat on demand when a magnetic field is applied, enabling reliable transition between submerged and ALI culture. In this work, we prototype a functional ALI microboat platform, with integrated stiffness-tunable polyacrylamide hydrogel surfaces, and validate the use of this technology with a model epithelial cell line. We verify sufficient transport through the hydrogel base to maintain cell viability and stimulate cultures, using a model nanoparticle with known toxicity. We then demonstrate significant morphological and functional effects on epithelial barrier formation, suggesting that substrate stiffness is an important parameter to consider in the design of in vitro epithelial ALI models for drug discovery and fundamental research.
Asunto(s)
Técnicas de Cultivo de Célula , Células Epiteliales/citología , Hidrogeles/química , Aire , Supervivencia Celular , Humanos , Fenómenos Magnéticos , Tamaño de la Partícula , Porosidad , Propiedades de SuperficieRESUMEN
Air pollution stimulates airway epithelial secretion through a cholinergic reflex that is unaffected in cystic fibrosis (CF), yet a strong correlation is observed between passive smoke exposure in the home and impaired lung function in CF children. Our aim was to study the effects of low smoke concentrations on cystic fibrosis transmembrane conductance regulator (CFTR) function in vitro. Cigarette smoke extract stimulated robust anion secretion that was transient, mediated by CFTR, and dependent on cAMP-dependent protein kinase activation. Secretion was initiated by reactive oxygen species (ROS) and mediated by at least two distinct pathways: autocrine activation of EP4 prostanoid receptors and stimulation of Ca2+ store-operated cAMP signaling. The response was absent in cells expressing the most common disease-causing mutant F508del-CFTR. In addition to the initial secretion, prolonged exposure of non-CF bronchial epithelial cells to low levels of smoke also caused a gradual decline in CFTR functional expression. F508del-CFTR channels that had been rescued by the CF drug combination VX-809 (lumacaftor) + VX-770 (ivacaftor) were more sensitive to this downregulation than wild-type CFTR. The results suggest that CFTR-mediated secretion during acute cigarette smoke exposure initially protects the airway epithelium while prolonged exposure reduces CFTR functional expression and reduces the efficacy of CF drugs.
Asunto(s)
Bronquios/efectos de los fármacos , AMP Cíclico/metabolismo , Regulador de Conductancia de Transmembrana de Fibrosis Quística/agonistas , Células Epiteliales/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Contaminación por Humo de Tabaco/efectos adversos , Aminofenoles/farmacología , Aminopiridinas/farmacología , Comunicación Autocrina/efectos de los fármacos , Benzodioxoles/farmacología , Bronquios/metabolismo , Bronquios/patología , Señalización del Calcio/efectos de los fármacos , Línea Celular , Fibrosis Quística/tratamiento farmacológico , Fibrosis Quística/genética , Fibrosis Quística/metabolismo , Fibrosis Quística/patología , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Células Epiteliales/metabolismo , Células Epiteliales/patología , Humanos , Mutación , Quinolonas/farmacología , Subtipo EP4 de Receptores de Prostaglandina E/agonistas , Subtipo EP4 de Receptores de Prostaglandina E/metabolismo , Sistemas de Mensajero Secundario/efectos de los fármacos , Vías Secretoras/efectos de los fármacosRESUMEN
Transepithelial bicarbonate secretion by human airway submucosal glands and surface epithelial cells is crucial to maintain the pH-sensitive innate defence mechanisms of the lung. cAMP agonists stimulate HCO3- secretion via coordinated increases in basolateral HCO3- influx and accumulation, as well as CFTR-dependent HCO3- efflux at the luminal membrane of airway epithelial cells. Here, we investigated the regulation of a basolateral located, DIDS-sensitive, Cl-/HCO3- exchanger, anion exchanger 2 (AE2; SLC4A2) which is postulated to act as an acid loader, and therefore potential regulator of HCO3- secretion, in human airway epithelial cells. Using intracellular pH measurements performed on Calu-3 cells, we demonstrate that the activity of the basolateral Cl-/HCO3- exchanger was significantly downregulated by cAMP agonists, via a PKA-independent mechanism and also required Ca2+ and calmodulin under resting conditions. AE2 contains potential phosphorylation sites by a calmodulin substrate, protein kinase CK2, and we demonstrated that AE2 activity was reduced in the presence of CK2 inhibition. Moreover, CK2 inhibition abolished the activity of AE2 in primary human nasal epithelia. Studies performed on mouse AE2 transfected into HEK-293T cells confirmed almost identical Ca2+/calmodulin and CK2 regulation to that observed in Calu-3 and primary human nasal cells. Furthermore, mouse AE2 activity was reduced by genetic knockout of CK2, an effect which was rescued by exogenous CK2 expression. Together, these findings are the first to demonstrate that CK2 is a key regulator of Cl--dependent HCO3- export at the serosal membrane of human airway epithelial cells.
Asunto(s)
Bicarbonatos/metabolismo , Quinasa de la Caseína II/metabolismo , Antiportadores de Cloruro-Bicarbonato/metabolismo , Cloruros/metabolismo , Mucosa Nasal/metabolismo , Animales , Línea Celular , Línea Celular Tumoral , Membrana Celular/metabolismo , AMP Cíclico/metabolismo , Células Epiteliales/metabolismo , Células HEK293 , Humanos , Concentración de Iones de Hidrógeno , RatonesRESUMEN
Cystic fibrosis (CF), a genetic disease caused by mutations in the CFTR gene, is a life-limiting disease characterized by chronic bacterial airway infection and severe inflammation. Some CFTR mutants have reduced responsiveness to cAMP/PKA signaling; hence, pharmacological agents that elevate intracellular cAMP are potentially useful for the treatment of CF. By inhibiting cAMP breakdown, phosphodiesterase (PDE) inhibitors stimulate CFTR in vitro and in vivo. Here, we demonstrate that PDE inhibition by RPL554, a drug that has been shown to cause bronchodilation in asthma and chronic obstructive pulmonary disease (COPD) patients, stimulates CFTR-dependent ion secretion across bronchial epithelial cells isolated from patients carrying the R117H/F508del CF genotype. RPL554-induced CFTR activity was further increased by the potentiator VX-770, suggesting an additional benefit by the drug combination. RPL554 also increased cilia beat frequency in primary human bronchial epithelial cells. The results indicate RPL554 may increase mucociliary clearance through stimulation of CFTR and increasing ciliary beat frequency and thus could provide a novel therapeutic option for CF.
Asunto(s)
Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Células Epiteliales/metabolismo , Isoquinolinas/farmacología , Inhibidores de Fosfodiesterasa 3/farmacología , Inhibidores de Fosfodiesterasa 4/farmacología , Pirimidinonas/farmacología , Asma/tratamiento farmacológico , Asma/metabolismo , Células Cultivadas , Células Epiteliales/efectos de los fármacos , Humanos , Transporte Iónico/efectos de los fármacos , Depuración Mucociliar/efectos de los fármacos , Enfermedad Pulmonar Obstructiva Crónica/metabolismoRESUMEN
Hypercapnia is clinically defined as an arterial blood partial pressure of CO2 of above 40 mmHg and is a feature of chronic lung disease. In previous studies we have demonstrated that hypercapnia modulates agonist-stimulated cAMP levels through effects on transmembrane adenylyl cyclase activity. In the airways, cAMP is known to regulate cystic fibrosis transmembrane conductance regulator (CFTR)-mediated anion and fluid secretion, which contributes to airway surface liquid homeostasis. The aim of the current work was to investigate if hypercapnia could modulate cAMP-regulated ion and fluid transport in human airway epithelial cells. We found that acute exposure to hypercapnia significantly reduced forskolin-stimulated elevations in intracellular cAMP as well as both adenosine- and forskolin-stimulated increases in CFTR-dependent transepithelial short-circuit current, in polarised cultures of Calu-3 human airway cells. This CO2 -induced reduction in anion secretion was not due to a decrease in HCO3 (-) transport given that neither a change in CFTR-dependent HCO3 (-) efflux nor Na(+) /HCO3 (-) cotransporter-dependent HCO3 (-) influx were CO2 -sensitive. Hypercapnia also reduced the volume of forskolin-stimulated fluid secretion over 24 h, yet had no effect on the HCO3 (-) content of the secreted fluid. Our data reveal that hypercapnia reduces CFTR-dependent, electrogenic Cl(-) and fluid secretion, but not CFTR-dependent HCO3 (-) secretion, which highlights a differential sensitivity of Cl(-) and HCO3 (-) transporters to raised CO2 in Calu-3 cells. Hypercapnia also reduced forskolin-stimulated CFTR-dependent anion secretion in primary human airway epithelia. Based on current models of airways biology, a reduction in fluid secretion, associated with hypercapnia, would be predicted to have important consequences for airways hydration and the innate defence mechanisms of the lungs.
Asunto(s)
Bicarbonatos/metabolismo , Dióxido de Carbono/metabolismo , Cloruros/metabolismo , AMP Cíclico/metabolismo , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Hipercapnia/metabolismo , Mucosa Respiratoria/metabolismo , Línea Celular , Células Cultivadas , Humanos , Transporte Iónico , Transducción de Señal , Sodio/metabolismoRESUMEN
Orthognathic surgical treatment conventionally relies on the use of full arch fixed orthodontic appliances. However, the introduction of orthodontic mini-implants has altered surgical options in terms of providing an alternative to fixation (intermaxillary fixation, IMF) screws and even to maxillary osteotomy. This paper describes the integration of mini-implants within orthognathic treatments in terms of 'surgery first' treatments and by introducing the concept of the conversion of bimaxillary cases into mandible-only surgery treatments.
Asunto(s)
Implantes Dentales , Métodos de Anclaje en Ortodoncia/instrumentación , Procedimientos Quirúrgicos Ortognáticos/instrumentación , Adolescente , Cefalometría/métodos , Femenino , Humanos , Técnicas de Fijación de Maxilares/instrumentación , Masculino , Maloclusión/cirugía , Maloclusión/terapia , Maloclusión de Angle Clase III/cirugía , Maloclusión de Angle Clase III/terapia , Osteotomía Mandibular/instrumentación , Osteotomía Maxilar/instrumentación , Persona de Mediana Edad , Miniaturización , Diente Molar/patología , Planificación de Atención al Paciente , Estrés Mecánico , Técnicas de Movimiento Dental/instrumentación , Adulto JovenRESUMEN
Conventional orthognathic wafers are made by a process involving manual movement of stone dental models and acrylic laboratory fabrication. In addition, a facebow record and semi-adjustable articulator system are required for maxillary osteotomy cases. This paper introduces a novel process of producing both intermediate and final orthognathic surgical wafers using a combination of computerized digital model simulation and three-dimensional print fabrication, without the need for either a facebow record or the additional ionizing radiation exposure associated with cone beam computerized tomography.