101
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Human amnion epithelial cells induced to express functional cystic fibrosis transmembrane conductance regulator. PLoS One 2012; 7:e46533. [PMID: 23029546 PMCID: PMC3460882 DOI: 10.1371/journal.pone.0046533] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 09/05/2012] [Indexed: 11/19/2022] Open
Abstract
Cystic fibrosis, an autosomal recessive disorder caused by a mutation in a gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR), remains a leading cause of childhood respiratory morbidity and mortality. The respiratory consequences of cystic fibrosis include the generation of thick, tenacious mucus that impairs lung clearance, predisposing the individual to repeated and persistent infections, progressive lung damage and shortened lifespan. Currently there is no cure for cystic fibrosis. With this in mind, we investigated the ability of human amnion epithelial cells (hAECs) to express functional CFTR. We found that hAECs formed 3-dimensional structures and expressed the CFTR gene and protein after culture in Small Airway Growth Medium (SAGM). We also observed a polarized CFTR distribution on the membrane of hAECs cultured in SAGM, similar to that observed in polarized airway cells in vivo. Further, hAECs induced to express CFTR possessed functional iodide/chloride (I−/Cl−) ion channels that were inhibited by the CFTR-inhibitor CFTR-172, indicating the presence of functional CFTR ion channels. These data suggest that hAECs may be a promising source for the development of a cellular therapy for cystic fibrosis.
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Abstract
Prenatal gene therapy aims to deliver genes to cells and tissues early in prenatal life, allowing correction of a genetic defect, before irreparable tissue damage has occurred. In contrast to postnatal gene therapy, prenatal application may target genes to a large population of stem cells, and the smaller fetal size allows a higher vector to target cell ratio to be achieved. Early gestation delivery may allow the development of immune tolerance to the transgenic protein, which would facilitate postnatal repeat vector administration if needed. Moreover, early delivery would avoid anti-vector immune responses which are often acquired in postnatal life. The NIH Recombinant DNA Advisory Committee considered that a candidate disease for prenatal gene therapy should pose serious morbidity and mortality risks to the fetus or neonate, and not have any effective postnatal treatment. Prenatal gene therapy would therefore be appropriate for life-threatening disorders, in which prenatal gene delivery maintains a clear advantage over cell transplantation or postnatal gene therapy. If deemed safer and more efficacious, prenatal gene therapy may be applicable for nonlethal conditions if adult gene transfer is unlikely to be of benefit. Many candidate diseases will be inherited congenital disorders such as thalassaemia or lysosomal storage disorders. However, obstetric conditions such as fetal growth restriction may also be treated using a targeted gene therapy approach. In each disease, the condition must be diagnosed prenatally, either via antenatal screening and prenatal diagnosis, for example, in the case of hemophilias, or by ultrasound assessment of the fetus, for example, congenital diaphragmatic hernia. In this chapter, we describe some examples of the candidate diseases and discuss how a prenatal gene therapy approach might work.
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Affiliation(s)
- Anna L David
- Prenatal Cell and Gene Therapy Group, EGA Institute for Women's Health, University College London, London, UK.
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103
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Abstract
Mucus pathology in cystic fibrosis (CF) has been known for as long as the disease has been recognized and is sometimes called mucoviscidosis. The disease is marked by mucus hyperproduction and plugging in many organs, which are usually most fatal in the airways of CF patients, once the problem of meconium ileus at birth is resolved. After the CF gene, CFTR, was cloned and its protein product identified as a cAMP-regulated Cl(-) channel, causal mechanisms underlying the strong mucus phenotype of the disease became obscure. Here we focus on mucin genes and polymeric mucin glycoproteins, examining their regulation and potential relationships to a dysfunctional cystic fibrosis transmembrane conductance regulator (CFTR). Detailed examination of CFTR expression in organs and different cell types indicates that changes in CFTR expression do not always correlate with the severity of CF disease or mucus accumulation. Thus, the mucus hyperproduction that typifies CF does not appear to be a direct cause of a defective CFTR but, rather, to be a downstream consequence. In organs like the lung, up-regulation of mucin gene expression by inflammation results from chronic infection; however, in other instances and organs, the inflammation may have a non-infectious origin. The mucus plugging phenotype of the β-subunit of the epithelial Na(+) channel (βENaC)-overexpressing mouse is proving to be an archetypal example of this kind of inflammation, with a dehydrated airway surface/concentrated mucus gel apparently providing the inflammatory stimulus. Data indicate that the luminal HCO(3)(-) deficiency recently described for CF epithelia may also provide such a stimulus, perhaps by causing a mal-maturation of mucins as they are released onto luminal surfaces. In any event, the path between CFTR dysfunction and mucus hyperproduction has proven tortuous, and its unraveling continues to offer its own twists and turns, along with fascinating glimpses into biology.
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Affiliation(s)
- Silvia M Kreda
- Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina, Chapel Hill, NC 27517-7248, USA
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104
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Hartl D, Gaggar A, Bruscia E, Hector A, Marcos V, Jung A, Greene C, McElvaney G, Mall M, Döring G. Innate immunity in cystic fibrosis lung disease. J Cyst Fibros 2012; 11:363-82. [PMID: 22917571 DOI: 10.1016/j.jcf.2012.07.003] [Citation(s) in RCA: 173] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 06/29/2012] [Accepted: 07/02/2012] [Indexed: 12/16/2022]
Abstract
Chronic lung disease determines the morbidity and mortality of cystic fibrosis (CF) patients. The pulmonary immune response in CF is characterized by an early and non-resolving activation of the innate immune system, which is dysregulated at several levels. Here we provide a comprehensive overview of innate immunity in CF lung disease, involving (i) epithelial dysfunction, (ii) pathogen sensing, (iii) leukocyte recruitment, (iv) phagocyte impairment, (v) mechanisms linking innate and adaptive immunity and (iv) the potential clinical relevance. Dissecting the complex network of innate immune regulation and associated pro-inflammatory cascades in CF lung disease may pave the way for novel immune-targeted therapies in CF and other chronic infective lung diseases.
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Affiliation(s)
- D Hartl
- Department of Pediatrics I, University of Tübingen, Tübingen, Germany.
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105
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Kunzelmann K, Tian Y, Martins JR, Faria D, Kongsuphol P, Ousingsawat J, Wolf L, Schreiber R. Airway epithelial cells--functional links between CFTR and anoctamin dependent Cl- secretion. Int J Biochem Cell Biol 2012; 44:1897-900. [PMID: 22710346 DOI: 10.1016/j.biocel.2012.06.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 06/02/2012] [Accepted: 06/11/2012] [Indexed: 11/29/2022]
Abstract
Airways consist of a heterogeneous population of cells, comprising ciliated cells, Clara cells and goblet cells. Electrolyte secretion by the airways is necessary to produce the airway surface liquid that allows for mucociliary clearance of the lungs. Secretion is driven by opening of Cl(-) selective ion channels in the apical membrane of airway epithelial cells, through either receptor mediated increase in intracellular cAMP or cytosolic Ca(2+). Traditionally cAMP-dependent and Ca(2+)-dependent secretory pathways are regarded as independent. However, this concept has been challenged recently. With identification of the Ca(2+) activated Cl(-) channel TMEM16A (anoctamin 1) and with detailed knowledge of the cAMP-regulated cystic fibrosis transmembrane conductance regulator (CFTR), it has become possible to look more closely into this relationship.
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Affiliation(s)
- Karl Kunzelmann
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany.
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106
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Collawn JF, Lazrak A, Bebok Z, Matalon S. The CFTR and ENaC debate: how important is ENaC in CF lung disease? Am J Physiol Lung Cell Mol Physiol 2012; 302:L1141-6. [PMID: 22492740 PMCID: PMC3379041 DOI: 10.1152/ajplung.00036.2012] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 04/02/2012] [Indexed: 01/07/2023] Open
Abstract
Cystic fibrosis (CF) is caused by the loss of the cystic fibrosis transmembrane conductance regulator (CFTR) function and results in a respiratory phenotype that is characterized by dehydrated mucus and bacterial infections that affect CF patients throughout their lives. Much of the morbidity and mortality in CF results from a failure to clear bacteria from the lungs. What causes the defect in the bacterial clearance in the CF lung has been the subject of an ongoing debate. Here we discuss the arguments for and against the role of the epithelial sodium channel, ENaC, in the development of CF lung disease.
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Affiliation(s)
- James F Collawn
- Department of Cell, Developmental and Integrative Biology, School of Medicine, University of Alabama at Birmingham, 35294-0005, USA.
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107
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Cho DY, Hwang PH, Illek B, Fischer H. Acid and base secretion in freshly excised nasal tissue from cystic fibrosis patients with ΔF508 mutation. Int Forum Allergy Rhinol 2012; 1:123-7. [PMID: 22034590 DOI: 10.1002/alr.20028] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Cystic fibrosis (CF) is caused by a misfunctional CF transmembrane conductance regulator (CFTR) protein, which is believed to contributes to the regulation of the airway surface liquid (ASL) pH. This study investigated acid and base secretion in freshly excised human nasal tissues from CF patients homozygous for the ΔF508 mutation. METHODS Human nasal mucosa was collected during sinus surgery and investigated in Ussing chambers. Mucosal equilibrium pH values and rate of acid and base secretion were determined using the pH-stat technique. RESULTS The equilibrium pH of nasal epithelia from ΔF508 CF patients with chronic rhinosinusitis (CRS) was pH = 7.08 ± 0.09 and was significantly lower compared to nasal epithelia from CRS patients without CF (pH = 7.33 ± 0.06) and normal subjects (pH = 7.34 ± 0.08, n = 6). The rate of base secretion in CF nasal tissues was 11.8 ± 2.4 nmol · min(−1) · cm(−2), which was significantly lower than normal (57.2 ± 9.2 nmol · min(−1) · cm(−2)). The HCO3(−) secretory rate was further increased by forskolin by 16.1% in normal, but not in CF tissues. CONCLUSION Our data suggests that CF patients exhibited significantly lower base secretion by the nasal airway epithelium. It is possible that improper regulation of ASL pH in CF may negatively impact the innate host defense system.
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Affiliation(s)
- Do-Yeon Cho
- Division of Rhinology, Department of Otolaryngology–Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA, USA
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108
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Li X, Comellas AP, Karp PH, Ernst SE, Moninger TO, Gansemer ND, Taft PJ, Pezzulo AA, Rector MV, Rossen N, Stoltz DA, McCray PB, Welsh MJ, Zabner J. CFTR is required for maximal transepithelial liquid transport in pig alveolar epithelia. Am J Physiol Lung Cell Mol Physiol 2012; 303:L152-60. [PMID: 22637155 DOI: 10.1152/ajplung.00116.2012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A balance between alveolar liquid absorption and secretion is critical for maintaining optimal alveolar subphase liquid height and facilitating gas exchange in the alveolar space. However, the role of cystic fibrosis transmembrane regulator protein (CFTR) in this homeostatic process has remained elusive. Using a newly developed porcine model of cystic fibrosis, in which CFTR is absent, we investigated ion transport properties and alveolar liquid transport in isolated type II alveolar epithelial cells (T2AECs) cultured at the air-liquid interface. CFTR was distributed exclusively to the apical surface of cultured T2AECs. Alveolar epithelia from CFTR(-/-) pigs failed to increase liquid absorption in response to agents that increase cAMP, whereas cAMP-stimulated liquid absorption in CFTR(+/-) epithelia was similar to that in CFTR(+/+) epithelia. Expression of recombinant CFTR restored stimulated liquid absorption in CFTR(-/-) T2AECs but had no effect on CFTR(+/+) epithelia. In ex vivo studies of nonperfused lungs, stimulated liquid absorption was defective in CFTR(-/-) alveolar epithelia but similar between CFTR(+/+) and CFTR(+/-) epithelia. When epithelia were studied at the air-liquid interface, elevating cAMP levels increased subphase liquid height in CFTR(+/+) but not in CFTR(-/-) T2AECs. Our findings demonstrate that CFTR is required for maximal liquid absorption under cAMP stimulation, but it is not the rate-limiting factor. Furthermore, our data define a role for CFTR in liquid secretion by T2AECs. These insights may help to develop new treatment strategies for pulmonary edema and respiratory distress syndrome, diseases in which lung liquid transport is disrupted.
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Affiliation(s)
- Xiaopeng Li
- Department of Internal Medicine, University of Iowa, Iowa City, USA
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109
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Abstract
Native small airways must remain wet enough to be pliable and support ciliary clearance, but dry enough to remain patent for gas flow. The airway epithelial lining must both absorb and secrete ions to maintain a critical level of fluid on its surface. Despite frequent involvement in lung diseases, the minuscule size has limited studies of peripheral airways. To meet this challenge, we used a capillary to construct an Ussing chamber (area <1 mm(2)) to measure electrolyte transport across small native airways (∼1 mm ø) from pig lung. Transepithelial potentials (V(t)) were recorded in open circuit conditions while applying constant current pulses across the luminal surface of dissected airways to calculate transepithelial electrical conductance (G(t)) and equivalent short circuit current (I(eq)(sc)) in the presence and absence of selected Na(+) and Cl(-) transport inhibitors (amiloride, GlyH-101, Niflumic acid) and agonists (Forskolin + IBMX, UTP). Considered together the responses suggest an organ composed of both secreting and absorbing epithelia that constitutively and concurrently transport fluids into and out of the airway, i.e. in opposite directions. Since the epithelial lining of small airways is arranged in long, accordion-like rows of pleats and folds that run axially down the lumen, we surmise that cells within the pleats are mainly secretory while the cells of the folds are principally absorptive. This structural arrangement could provide local fluid transport from within the pleats toward the luminal folds that may autonomously regulate the local surface fluid volume for homeostasis while permitting acute responses to maintain clearance.
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Affiliation(s)
- A K M Shamsuddin
- Department of Pediatrics, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0830, USA
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110
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Oakland M, Sinn PL, McCray PB. Advances in cell and gene-based therapies for cystic fibrosis lung disease. Mol Ther 2012; 20:1108-15. [PMID: 22371844 DOI: 10.1038/mt.2012.32] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Cystic fibrosis (CF) is a disease characterized by airway infection, inflammation, remodeling, and obstruction that gradually destroy the lungs. Direct delivery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene to airway epithelia may offer advantages, as the tissue is accessible for topical delivery of vectors. Yet, physical and host immune barriers in the lung present challenges for successful gene transfer to the respiratory tract. Advances in gene transfer approaches, tissue engineering, and novel animal models are generating excitement within the CF research field. This review discusses current challenges and advancements in viral and nonviral vectors, cell-based therapies, and CF animal models.
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Affiliation(s)
- Mayumi Oakland
- Department of Microbiology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa 52242, USA
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111
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Dab2 is a key regulator of endocytosis and post-endocytic trafficking of the cystic fibrosis transmembrane conductance regulator. Biochem J 2012; 441:633-43. [PMID: 21995445 DOI: 10.1042/bj20111566] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
CFTR (cystic fibrosis transmembrane conductance regulator) is expressed in the apical membrane of epithelial cells. Cell-surface CFTR levels are regulated by endocytosis and recycling. A number of adaptor proteins including AP-2 (μ2 subunit) and Dab2 (Disabled-2) have been proposed to modulate CFTR internalization. In the present study we have used siRNA (small interfering RNA)-mediated silencing of these adaptors to test their roles in the regulation of CFTR cell-surface trafficking and stability in human airway epithelial cells. The results indicate that μ2 and Dab2 performed partially overlapping, but divergent, functions. While μ2 depletion dramatically decreased CFTR endocytosis with little effect on the half-life of the CFTR protein, Dab2 depletion increased the CFTR half-life ~3-fold, in addition to inhibiting CFTR endocytosis. Furthermore, Dab2 depletion inhibited CFTR trafficking from the sorting endosome to the recycling compartment, as well as delivery of CFTR to the late endosome, thus providing a mechanistic explanation for increased CFTR expression and half-life. To test whether two E3 ligases were required for the endocytosis and/or down-regulation of surface CFTR, we siRNA-depleted CHIP [C-terminus of the Hsc (heat-shock cognate) 70-interacting protein] and c-Cbl (casitas B-lineage lymphoma). We demonstrate that CHIP and c-Cbl depletion have no effect on CFTR endocytosis, but c-Cbl depletion modestly enhanced the half-life of CFTR. The results of the present study define a significant role for Dab2 both in the endocytosis and post-endocytic fate of CFTR.
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112
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CFTR expression analysis in human nasal epithelial cells by flow cytometry. PLoS One 2011; 6:e27658. [PMID: 22163268 PMCID: PMC3233544 DOI: 10.1371/journal.pone.0027658] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 10/21/2011] [Indexed: 01/08/2023] Open
Abstract
Rationale Unbiased approaches that study aberrant protein expression in primary airway epithelial cells at single cell level may profoundly improve diagnosis and understanding of airway diseases. We here present a flow cytometric procedure to study CFTR expression in human primary nasal epithelial cells from patients with Cystic Fibrosis (CF). Our novel approach may be important in monitoring of therapeutic responses, and better understanding of CF disease at the molecular level. Objectives Validation of a panel of CFTR-directed monoclonal antibodies for flow cytometry and CFTR expression analysis in nasal epithelial cells from healthy controls and CF patients. Methods We analyzed CFTR expression in primary nasal epithelial cells at single cell level using flow cytometry. Nasal cells were stained for pan-Cytokeratin, E cadherin, and CD45 (to discriminate epithelial cells and leukocytes) in combination with intracellular staining of CFTR. Healthy individuals and CF patients were compared. Measurements and Main Results We observed various cellular populations present in nasal brushings that expressed CFTR protein at different levels. Our data indicated that CF patients homozygous for F508del express varying levels of CFTR protein in nasal epithelial cells, although at a lower level than healthy controls. Conclusion CFTR protein is expressed in CF patients harboring F508del mutations but at lower levels than in healthy controls. Multicolor flow cytometry of nasal cells is a relatively simple procedure to analyze the composition of cellular subpopulations and protein expression at single cell level.
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113
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Jones LC, Moussa L, Fulcher ML, Zhu Y, Hudson EJ, O'Neal WK, Randell SH, Lazarowski ER, Boucher RC, Kreda SM. VAMP8 is a vesicle SNARE that regulates mucin secretion in airway goblet cells. J Physiol 2011; 590:545-62. [PMID: 22144578 DOI: 10.1113/jphysiol.2011.222091] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mucin secretion is an innate defence mechanism, which is noxiously upregulated in obstructive lung diseases (e.g. chronic obstructive pulmonary disease (COPD), cystic fibrosis and asthma). Mucin granule exocytosis is regulated by specific protein complexes, but the SNARE exocytotic core has not been defined in airway goblet cells. In this study, we identify VAMP8 as one of the SNAREs regulating mucin granule exocytosis. VAMP8 mRNA was present in human airway and lung epithelial cells, and deep-sequencing and expression analyses of airway epithelial cells revealed that VAMP8 transcripts were expressed at 10 times higher levels than other VAMP mRNAs. In human airway epithelial cell cultures and freshly excised tissues, VAMP8 immunolocalised mainly to goblet cell mucin granules. The function of VAMP8 in airway mucin secretion was tested by RNA interference techniques. Both VAMP8 short interfering RNAs (siRNAs) and short hairpin RNAs (shRNAs) reduced mucin secretion induced by PAR agonists, neutrophil elastase and ATP in two airway epithelial cell culture models. Notably, basal (non-agonist elicited) mucin secretion was also reduced in these experiments. VAMP8 knockdown was also effective in decreasing mucin secretion in airway epithelial cell cultures with induced mucous metaplasia/mucin hypersecretion. Unlike VAMP8 silencing, knockdown of VAMP2 or VAMP3 did not affect mucin secretion. Importantly, in VAMP8 knock-out (KO) mice with IL-13-induced mucous metaplasia, mucin content in the bronchoalveolar lavage (BAL) and ATP-stimulated mucin secretion in the trachea were reduced compared to WT-matched littermates. Our data indicate that VAMP8 is an essential SNARE in airway mucin granule exocytosis. Reduction of VAMP8 activity/expression may provide a novel therapeutic target to ameliorate airway mucus obstruction in lung diseases.
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Affiliation(s)
- Lisa C Jones
- Cystic Fibrosis/Pulmonary Research and Treatment Centre, The University of North Carolina at Chapel Hill, 4029A Thurston Bowles Building, Chapel Hill, NC 27599-7248, USA
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114
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Grubb BR, O'Neal WK, Ostrowski LE, Kreda SM, Button B, Boucher RC. Transgenic hCFTR expression fails to correct β-ENaC mouse lung disease. Am J Physiol Lung Cell Mol Physiol 2011; 302:L238-47. [PMID: 22003093 DOI: 10.1152/ajplung.00083.2011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The relationships between airway epithelial Cl(-) secretion-Na(+) absorption balance, airway surface liquid (ASL) homeostasis, and lung disease were investigated in selected transgenic mice. 1) To determine if transgenic overexpression of wild-type (WT) human CFTR (hCFTR) accelerated Cl(-) secretion and regulated Na(+) absorption in murine airways, we utilized a Clara cell secretory protein (CCSP)-specific promoter to generate mice expressing airway-specific hCFTR. Ussing chamber studies revealed significantly (∼2.5-fold) elevated basal Cl(-) secretory currents in CCSP-hCFTR transgenic mouse airways. Endogenous murine airway Na(+) absorption was not regulated by hCFTR, and these mice exhibited no lung disease. 2) We tested whether hCFTR, transgenically expressed on a transgenic mouse background overexpressing the β-subunit of the epithelial Na(+) channel (β-ENaC), restored ion transport balance and ASL volume homeostasis and ameliorated lung disease. Both transgenes were active in CCSP-hCFTR/β-ENaC transgenic mouse airways, which exhibited an elevated basal Cl(-) secretion and Na(+) hyperabsorption. However, the airway disease characteristic of β-ENaC mice persisted. Confocal studies of ASL volume homeostasis in cultured tracheal cells revealed ASL autoregulation to a height of ∼6 μm in WT and CCSP-hCFTR cultures, whereas ASL was reduced to <4 μm in β-ENaC and CCSP-hCFTR/β-ENaC cultures. We conclude that 1) hCFTR overexpression increases basal Cl(-) secretion but does not regulate Na(+) transport in WT mice and 2) transgenic hCFTR produces increased Cl(-) secretion, but not regulation of Na(+) channels, in β-ENaC mouse airways and does not ameliorate β-ENaC mouse lung disease.
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Affiliation(s)
- B R Grubb
- Cystic Fibrosis/Pulmonary Research and Treatment Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7248, USA.
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Ott CJ, Bischof JM, Unti KM, Gillen AE, Leir SH, Harris A. Nucleosome occupancy reveals regulatory elements of the CFTR promoter. Nucleic Acids Res 2011; 40:625-37. [PMID: 21948798 PMCID: PMC3258145 DOI: 10.1093/nar/gkr754] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Access to regulatory elements of the genome can be inhibited by nucleosome core particles arranged along the DNA strand. Hence, sites that are accessible by transcription factors may be located by using nuclease digestion to identify the relative nucleosome occupancy of a genomic region. In order to define novel cis regulatory elements in the ∼2.7-kb promoter region of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, we define its nucleosome occupancy. This profile reveals the precise positions of nucleosome-free regions (NFRs), both cell-type specific and others apparently unrelated to CFTR-expression level and offer the first high-resolution map of the chromatin structure of the entire CFTR promoter in relevant cell types. Several of these NFRs are strongly bound by nuclear factors in a sequence-specific manner, and directly influence CFTR promoter activity. Sequences within the NFR1 and NFR4 elements are highly conserved in many human gene promoters. Moreover, NFR1 contributes to promoter activity of another gene, angiopoietin-like 3 (ANGPTL3), while NFR4 is constitutively nucleosome-free in promoters genome wide. Conserved motifs within NFRs of the CFTR promoter also show a high level of protection from DNase I digestion genome-wide, and likely have important roles in the positioning of nucleosome core particles more generally.
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Affiliation(s)
- Christopher J Ott
- Human Molecular Genetics Program, Children's Memorial Research Center, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL 60614, USA
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116
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Genomic approaches to studying CFTR transcriptional regulation. Methods Mol Biol 2011. [PMID: 21594786 DOI: 10.1007/978-1-61779-117-8_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The CFTR gene was identified over 20 years ago, and yet how the gene is transcriptionally regulated is not fully understood. Completion of the human genome sequence has encouraged a new generation of genomic techniques that can be used to identify and characterize the regulatory elements of the genome, which are often hidden in non-coding regions. In this chapter we describe two techniques that we have used to identify regulatory regions of the CFTR locus: DNase-chip, which utilizes DNase I-digested chromatin hybridized to tiled microarrays in order to locate regions of the CFTR locus that are "open" and thus likely regions of transcription factor binding; and quantitative chromosome conformation capture (q3C), which uses quantitative PCR analysis of digested and ligated, crosslinked chromosomes to measure physical interactions between distal genomic regions. When used together, these methods provide a powerful avenue to discover transcriptional regulatory elements within large genomic regions.
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117
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Dannhoffer L, Billet A, Jollivet M, Melin-Heschel P, Faveau C, Becq F. Stimulation of Wild-Type, F508del- and G551D-CFTR Chloride Channels by Non-Toxic Modified pyrrolo[2,3-b]pyrazine Derivatives. Front Pharmacol 2011; 2:48. [PMID: 21897819 PMCID: PMC3159890 DOI: 10.3389/fphar.2011.00048] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 08/03/2011] [Indexed: 11/17/2022] Open
Abstract
Cystic fibrosis (CF) is a major inherited disorder involving abnormalities of fluid and electrolyte transport in a number of different organs due to abnormal function of cystic fibrosis transmembrane conductance regulator (CFTR) protein. We recently identified a family of CFTR activators, which contains the hit: RP107 [7-n-butyl-6-(4-hydroxyphenyl)[5H]-pyrrolo[2,3-b]pyrazine]. Here, we further evaluated the effect of the chemical modifications of the RP107-OH radical on CFTR activation. The replacement of the OH radical by a fluorine atom at position 2 (RP193) or 4 (RP185) significantly decreased the toxicity of the compounds without altering the ability to activate CFTR, especially for RP193. The non-toxic compound RP193 has no effect on cAMP production but stimulates the channel activity of wild-type CFTR in stably transfected CHO cells, in human bronchial epithelial NuLi-1 cells, and in primary culture of human bronchial epithelial cells (HBEC). Whole-cell and single patch-clamp recordings showed that RP193 induced a linear, time- and voltage-independent current, which was fully inhibited by two different and selective CFTR inhibitors (CFTRinh-172 and GPinh5a). Moreover, RP193 stimulates CFTR in temperature-rescued CuFi-1 (F508del/F508del) HBEC and in CHO cells stably expressing G551D-CFTR. This study shows that it is feasible to reduce cytotoxicity of chemical compounds without affecting their potency to activate CFTR and to rescue the class 2 F508del-CFTR and class 3 G551D-CFTR CF mutant activities.
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Affiliation(s)
- Luc Dannhoffer
- Institut de Physiologie et Biologie Cellulaires, UMR 6187, Université de Poitiers CNRS, Poitiers, France
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Borthwick LA, Botha P, Verdon B, Brodlie MJ, Gardner A, Bourn D, Johnson GE, Gray MA, Fisher AJ. Is CFTR-delF508 really absent from the apical membrane of the airway epithelium? PLoS One 2011; 6:e23226. [PMID: 21826241 PMCID: PMC3149652 DOI: 10.1371/journal.pone.0023226] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 07/10/2011] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Understanding where mutant CFTR is localised in airway epithelia is essential in guiding the best therapeutic approach to correct the dysfunction of the CFTR protein. The widely held paradigm is that CF patients harbouring the commonest mutation, CFTR-delF508, trap CFTR within the endoplasmic reticulum and target it for degradation. However there are conflicting reports concerning expression and localisation of CFTR-delF508 in lung tissue. To attempt to resolve this fundamental issue we developed a novel approach to measure CFTR-delF508 in the lower airways of patients who have undergone lung transplantation for advanced CF. By sampling CF and non-CF epithelium simultaneously from the same individual, confounding factors of different airway microenvironments which may have influenced previous observations can be overcome. METHODS Epithelia sampled by bronchial brushing above (CF) and below (non-CF) the bronchial anastomosis were stained for CFTR and the localisation and level of expression assessed (n = 12). RESULTS There was no significant difference in the proportion of tall columnar cells showing CFTR immunostaining as a discrete band at the apical membrane in cells harbouring the CFTR-delF508 mutation compared to non-CF cells (p = 0.21, n = 12). However, the amount of CFTR expressed at the apical surface was reduced by ∼50% in CF cells compared to non-CF cells (p = 0.04, n = 5). CONCLUSIONS Our novel observation challenges the prevailing paradigm that CFTR is essentially absent from the apical membrane of respiratory cells harbouring the CFTR-delF508 mutation. Moreover, it raises the possibility that the new generation of CFTR potentiators may offer a realistic therapeutic option for CF patients.
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Affiliation(s)
- Lee A. Borthwick
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Phil Botha
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Bernard Verdon
- Institute for Cell & Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Malcolm J. Brodlie
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Aaron Gardner
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David Bourn
- Institute of Human Genetics, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Gail E. Johnson
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Mike A. Gray
- Institute for Cell & Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Andrew J. Fisher
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
- * E-mail:
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119
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Finkbeiner WE, Zlock LT, Morikawa M, Lao AY, Dasari V, Widdicombe JH. Cystic fibrosis and the relationship between mucin and chloride secretion by cultures of human airway gland mucous cells. Am J Physiol Lung Cell Mol Physiol 2011; 301:L402-14. [PMID: 21724859 DOI: 10.1152/ajplung.00210.2010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated how cystic fibrosis (CF) alters the relationship between Cl(-) and mucin secretion in cultures of non-CF and CF human tracheobronchial gland mucous (HTGM and CFTGM, respectively) cells. Biochemical studies showed that HTMG cells secreted typical airway mucins, and immunohistochemical studies showed that these cells expressed MUC1, MUC4, MUC5B, MUC8, MUC13, MUC16, and MUC20. Effects of cumulative doses of methacholine (MCh), phenylephrine (Phe), isoproterenol (Iso), and ATP on mucin and Cl(-) secretion were studied on HTGM and CFTGM cultures. Baseline mucin secretion was not significantly altered in CFTGM cells, and the increases in mucin secretion induced by mediators were unaltered (Iso, Phe) or slightly decreased (MCh, ATP). Across mediators, there was no correlation between the maximal increases in Cl(-) secretion and mucin secretion. In HTGM cells, the Cl(-) channel blocker, diphenylamine-2-carboxylic acid, greatly inhibited Cl(-) secretion but did not alter mucin release. In HTGM cells, mediators (10(-5) M) increased mucin secretion in the rank order ATP > Phe = Iso > MCh. They increased Cl(-) secretion in the sequence ATP > MCh ≈ Iso > Phe. The responses in Cl(-) secretion to MCh, ATP, and Phe were unaltered by CF, but the response to Iso was greatly reduced. We conclude that mucin secretion by cultures of human tracheobronchial gland cells is independent of Cl(-) secretion, at baseline, and is unaltered in CF; that the ratio of Cl(-) secretion to mucus secretion varies markedly depending on mediator; and that secretions induced by stimulation of β-adrenergic receptors will be abnormally concentrated in CF.
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Affiliation(s)
- Walter E Finkbeiner
- Department of Pathology, University of California, San Francisco, 94110, USA.
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Ostedgaard LS, Meyerholz DK, Chen JH, Pezzulo AA, Karp PH, Rokhlina T, Ernst SE, Hanfland RA, Reznikov LR, Ludwig PS, Rogan MP, Davis GJ, Dohrn CL, Wohlford-Lenane C, Taft PJ, Rector MV, Hornick E, Nassar BS, Samuel M, Zhang Y, Richter SS, Uc A, Shilyansky J, Prather RS, McCray PB, Zabner J, Welsh MJ, Stoltz DA. The ΔF508 mutation causes CFTR misprocessing and cystic fibrosis-like disease in pigs. Sci Transl Med 2011; 3:74ra24. [PMID: 21411740 DOI: 10.1126/scitranslmed.3001868] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel. The most common CF-associated mutation is ΔF508, which deletes a phenylalanine in position 508. In vitro studies indicate that the resultant protein, CFTR-ΔF508, is misprocessed, although the in vivo consequences of this mutation remain uncertain. To better understand the effects of the ΔF508 mutation in vivo, we produced CFTR(ΔF508/ΔF508) pigs. Our biochemical, immunocytochemical, and electrophysiological data on CFTR-ΔF508 in newborn pigs paralleled in vitro predictions. They also indicated that CFTR(ΔF508/ΔF508) airway epithelia retain a small residual CFTR conductance, with maximal stimulation producing ~6% of wild-type function. Cyclic adenosine 3',5'-monophosphate (cAMP) agonists were less potent at stimulating current in CFTR(Δ)(F508/)(Δ)(F508) epithelia, suggesting that quantitative tests of maximal anion current may overestimate transport under physiological conditions. Despite residual CFTR function, four older CFTR(ΔF508/ΔF508) pigs developed lung disease similar to human CF. These results suggest that this limited CFTR activity is insufficient to prevent lung or gastrointestinal disease in CF pigs. These data also suggest that studies of recombinant CFTR-ΔF508 misprocessing predict in vivo behavior, which validates its use in biochemical and drug discovery experiments. These findings help elucidate the molecular pathogenesis of the common CF mutation and will guide strategies for developing new therapeutics.
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Affiliation(s)
- Lynda S Ostedgaard
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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Clunes MT, Boucher RC. Introduction to section I: overview of approaches to study cystic fibrosis pathophysiology. Methods Mol Biol 2011; 742:3-14. [PMID: 21547723 DOI: 10.1007/978-1-61779-120-8_1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Mutation of the CFTR chloride channel was identified as the genetic basis of cystic fibrosis over 20 years ago; however, correlation of the pathophysiological changes occurring in CF lung disease with the mutation of a chloride channel is ongoing. The failure of innate lung defense in CF, and the subsequent cyclical microbial colonization of airways, explains the gross anatomical changes that occur in CF pathophysiology. However, ongoing research is focused on how the lack of the CFTR channel explains the failure of innate lung defense. Hydration status of the mucus blanket is key to understanding this link, and this series of chapters details the recent progress that has been made in understanding the interplay between ion transport activity and innate lung defense, and the initiation of CF lung pathophysiology.
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Affiliation(s)
- Mark T Clunes
- Department of Physiology and Neuroscience, St. George's University, True Blue Campus, Grenada, West Indies.
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Abstract
CFTR functions as a chloride channel at the apical membrane of airway, gastrointestinal, and other epithelial cells. Immunofluorescence microscopy is commonly used to assess the subcellular localization and relative abundance of CFTR. Visualization of heterologously overexpressed CFTR is typically unproblematic and straightforward, whereas detection of small quantities of endogenous CFTR in tissues can be challenging and requires highly specific antibodies and optimized staining protocols. CFTR tagged by green fluorescent protein can be employed to study trafficking in live cells. Tagging of CFTR with an extracellular epitope permits detection exclusively at the cell surface and subsequent chasing allows visualization of endocytic trafficking.
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123
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Wine JJ, Joo NS, Choi JY, Cho HJ, Krouse ME, Wu JV, Khansaheb M, Irokawa T, Ianowski J, Hanrahan JW, Cuthbert AW, Tran KV. Measurement of fluid secretion from intact airway submucosal glands. Methods Mol Biol 2011; 742:93-112. [PMID: 21547728 DOI: 10.1007/978-1-61779-120-8_6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Human airways are kept sterile by a mucosal innate defense system that includes mucus secretion. Mucus is secreted in healthy upper airways primarily by submucosal glands and consists of defense molecules mixed with mucins, electrolytes, and water and is also a major component of sputum. Mucus traps pathogens and mechanically removes them via mucociliary clearance while inhibiting their growth via molecular (e.g., lysozyme) and cellular (e.g., neutrophils, macrophages) defenses. Fluid secretion rates of single glands in response to various mediators can be measured by trapping the primary gland mucus secretions in an oil layer, where they form spherical bubbles that can be optically measured at any desired interval to provide detailed temporal analysis of secretion rates. The composition and properties of the mucus (e.g., solids, viscosity, pH) can also be determined. These methods have now been applied to mice, ferrets, cats, pigs, sheep, and humans, with a main goal of comparing gland secretion in control and CFTR-deficient humans and animals.
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Affiliation(s)
- Jeffrey J Wine
- Cystic Fibrosis Research Laboratory, Stanford University, Stanford, CA 94305-2130, USA.
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Abstract
A thin layer of airway surface liquid (ASL) lines the entire surface of the lung and is the first point of contact between the lung and the environment. Surfactants contained within this layer are secreted in the alveolar region and are required to maintain a low surface tension and to prevent alveolar collapse. Mucins are secreted into the ASL throughout the respiratory tract and serve to intercept inhaled pathogens, allergens and toxins. Their removal by mucociliary clearance (MCC) is facilitated by cilia beating and hydration of the ASL by active ion transport. Throughout the lung, secretion, ion transport and cilia beating are under purinergic control. Pulmonary epithelia release ATP into the ASL which acts in an autocrine fashion on P2Y(2) (ATP) receptors. The enzymatic network describes in Chap. 2 then mounts a secondary wave of signaling by surface conversion of ATP into adenosine (ADO), which induces A(2B) (ADO) receptor-mediated responses. This chapter offers a comprehensive description of MCC and the extensive ramifications of the purinergic signaling network on pulmonary surfaces.
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Zhang L, Limberis MP, Thompson C, Antunes MB, Luongo C, Wilson JM, Collins PL, Pickles RJ. α-Fetoprotein gene delivery to the nasal epithelium of nonhuman primates by human parainfluenza viral vectors. Hum Gene Ther 2010; 21:1657-64. [PMID: 20735256 DOI: 10.1089/hum.2010.065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Over the last two decades, enormous effort has been focused on developing virus-based gene delivery vectors to target the respiratory airway epithelium as a potential treatment for cystic fibrosis (CF) lung disease. However, amongst other problems, the efficiency of gene delivery to the differentiated airway epithelial cells of the lung has been too low for clinical benefit. Although not a target for CF therapy, the nasal epithelium exhibits cellular morphology and composition similar to that of the lower airways, thus representing an accessible and relevant tissue target for evaluating novel and improved gene delivery vectors. We previously reported that replication-competent human parainfluenza virus (PIV)-based vectors efficiently deliver the cystic fibrosis transmembrane conductance regulator gene to sufficient numbers of cultured CF airway epithelial cells to completely correct the bioelectric function of CF cells to normal levels, resulting in restoration of mucus transport. Here, using an in vitro model of rhesus airway epithelium, we demonstrate that PIV mediates efficient gene transfer in rhesus epithelium as in the human counterpart. Naive rhesus macaques were inoculated intranasally with a PIV vector expressing rhesus macaque α-fetoprotein (rhAFP), and expression was monitored longitudinally. rhAFP was detected in nasal lavage fluid and in serum samples, indicating that PIV-mediated gene transfer was effective and that rhAFP was secreted into both mucosal and serosal compartments. Although expression was transient, lasting up to 10 days, it paralleled virus replication, suggesting that as PIV was cleared, rhAFP expression was lost. No adverse reactions or signs of discomfort were noted, and only mild, transient elevations of a small number of inflammatory cytokines were measured at the peak of virus replication. In summary, rhAFP proved suitable for monitoring in vivo gene delivery over time, and PIV vectors appear to be promising airway-specific gene transfer vehicles that warrant further development.
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Affiliation(s)
- Liqun Zhang
- Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, 27759, USA.
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Fischer H, Illek B, Sachs L, Finkbeiner WE, Widdicombe JH. CFTR and calcium-activated chloride channels in primary cultures of human airway gland cells of serous or mucous phenotype. Am J Physiol Lung Cell Mol Physiol 2010; 299:L585-94. [PMID: 20675434 PMCID: PMC2957417 DOI: 10.1152/ajplung.00421.2009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Accepted: 07/30/2010] [Indexed: 11/22/2022] Open
Abstract
Using cell culture models, we have investigated the relative importance of cystic fibrosis transmembrane conductance regulator (CFTR) and calcium-activated chloride channels (CaCC) in Cl secretion by mucous and serous cells of human airway glands. In transepithelial recordings in Ussing chambers, the CFTR inhibitor CFTR(inh)-172 abolished 60% of baseline Cl secretion in serous cells and 70% in mucous. Flufenamic acid (FFA), an inhibitor of CaCC, reduced baseline Cl secretion by ∼20% in both cell types. Methacholine and ATP stimulated Cl secretion in both cell types, which was largely blocked by treatment with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) and partially by mucosal FFA or CFTR(inh)-172 with the exception of methacholine responses in mucous cells, which were not blocked by FFA and partially (∼60%) by CFTR(inh)-172. The effects of ionomycin on short-circuit current (I(sc)) were less than those of ATP or methacholine. Forskolin stimulated Cl secretion only if Cl in the mucosal medium was replaced by gluconate. In whole cell patch-clamp studies of single isolated cells, cAMP-induced Cl currents were ∼3-fold greater in serous than mucous cells. Ionomycin-induced Cl currents were 13 times (serous) or 26 times (mucous) greater than those generated by cAMP and were blocked by FFA. In serous cells, mRNA for transmembrane protein 16A (TMEM16A) was ∼10 times more abundant than mRNA for CFTR. In mucous cells it was ∼100 times more abundant. We conclude: 1) serous and mucous cells both make significant contributions to gland fluid secretion; 2) baseline Cl secretion in both cell types is mediated predominantly by CFTR, but CaCC becomes increasingly important after mediator-induced elevations of intracellular Ca; and 3) the high CaCC currents seen in patch-clamp studies and the high TMEM16A expression in intact polarized cells sheets are not reflected in transepithelial current recordings.
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Affiliation(s)
- Horst Fischer
- Children’s Hospital Oakland Research Institute, Oakland, California, USA
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Plog S, Mundhenk L, Bothe MK, Klymiuk N, Gruber AD. Tissue and cellular expression patterns of porcine CFTR: similarities to and differences from human CFTR. J Histochem Cytochem 2010; 58:785-97. [PMID: 20498480 PMCID: PMC2924795 DOI: 10.1369/jhc.2010.955377] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Accepted: 05/13/2010] [Indexed: 01/19/2023] Open
Abstract
Emerging porcine models of cystic fibrosis (CF) are expected to mimic the human disease more closely than current mouse models do. However, little is known of the tissue and cellular expression patterns of the porcine CF transmembrane conductance regulator (pCFTR) and possible differences from human CFTR (hCFTR). Here, the expression pattern of pCFTR was systematically established on the mRNA and protein levels. Using specific anti-pCFTR antibodies, the majority of the protein was immunohistochemically detected on paraffin-embedded sections and on cryostate sections in the apical cytosol of intestinal crypt epithelial cells, nasal, tracheal, and bronchial epithelial cells, and other select, mostly glandular epithelial cells. Confocal laser scanning microscopy with co-localization of the Golgi marker 58K localized the protein in the cytosol between the Golgi apparatus and the apical cell membrane with occasional punctate or diffuse staining of the apical membrane. The tissue and cellular distribution patterns were confirmed by RT-PCR from whole tissue lysates or select cells after laser capture microdissection. Thus, expression of pCFTR was found to largely resemble that of hCFTR except for the kidney, brain, and cutaneous glands, which lack expression in pigs. Species-specific differences between pCFTR and hCFTR may become relevant for future interpretations of the CF phenotype in pig models.
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Affiliation(s)
- Stephanie Plog
- Department of Veterinary Pathology, Faculty of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
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128
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van Barneveld A, Stanke F, Tamm S, Siebert B, Brandes G, Derichs N, Ballmann M, Junge S, Tümmler B. Functional analysis of F508del CFTR in native human colon. Biochim Biophys Acta Mol Basis Dis 2010; 1802:1062-9. [PMID: 20696241 DOI: 10.1016/j.bbadis.2010.08.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 07/28/2010] [Accepted: 08/02/2010] [Indexed: 11/16/2022]
Abstract
The major cystic fibrosis mutation F508del has been classified by experiments in animal and cell culture models as a temperature-sensitive mutant defective in protein folding, processing and trafficking, but literature data on F508del CFTR maturation and function in human tissue are inconsistent. In the present study the molecular pathology of F508del CFTR was characterized in freshly excised rectal mucosa by bioelectric measurement of the basic defect and CFTR protein analysis by metabolic labelling or immunoblot. The majority of investigated F508del homozygous subjects expressed low amounts of complex-glycosylated mature F508del CFTR and low residual F508del CFTR-mediated chloride secretory activity in the rectal mucosa. The finding that some F508del CFTR escapes the ER quality control in vivo substantiates the hope that the defective processing and trafficking of F508del CFTR can be corrected by pharmacological agents.
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Affiliation(s)
- Andrea van Barneveld
- Klinische Forschergruppe, OE 6710, Medizinische Hochschule Hannover, Hannover, Germany.
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Schmid A, Sutto Z, Schmid N, Novak L, Ivonnet P, Horvath G, Conner G, Fregien N, Salathe M. Decreased soluble adenylyl cyclase activity in cystic fibrosis is related to defective apical bicarbonate exchange and affects ciliary beat frequency regulation. J Biol Chem 2010; 285:29998-30007. [PMID: 20639512 DOI: 10.1074/jbc.m110.113621] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Human airway cilia contain soluble adenylyl cyclase (sAC) that produces cAMP upon HCO(3)(-)/CO(2) stimulation to increase ciliary beat frequency (CBF). Because apical HCO(3)(-) exchange depends on cystic fibrosis transmembrane conductance regulator (CFTR), malfunctioning CFTR might impair sAC-mediated CBF regulation in cells from patients with cystic fibrosis (CF). By Western blot, sAC isoforms are equally expressed in normal and CF airway epithelial cells, but CBF decreased more in CF than normal cells upon increased apical HCO(3)(-)/CO(2) exposure in part because of greater intracellular acidification from unbalanced CO(2) influx (estimated by 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) fluorescence). Importantly, ciliated cell-specific cAMP production (estimated by FRET fluorescence ratio changes of tagged cAMP-dependent protein kinase (PKA) subunits expressed under a ciliated cell-specific promoter) in response to increased apical HCO(3)(-)/CO(2) perfusion was higher in normal compared with CF cells. Inhibition of bicarbonate influx via CFTR (CFTR(inh)172) and inhibition of sAC (KH7) and PKA activation (H89) led to larger CBF declines in normal cells, now comparable with changes seen in CF cells. These inhibitors also reduced FRET changes in normal cells to the level of CF cells with the expected exception of H89, which does not prevent dissociation of the fluorescently tagged PKA subunits. Basolateral permeabilization and subsequent perfusion with HCO(3)(-)/CO(2) rescued CBF and FRET changes in CF cells to the level of normal cells. These results suggest that CBF regulation by sAC-produced cAMP could be impaired in CF, thereby possibly contributing to mucociliary dysfunction in this disease, at least during disease exacerbations when airway acidification is common.
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Affiliation(s)
- Andreas Schmid
- Division of Pulmonary and Critical Care, University of Miami, Miami, Florida 33136, USA.
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Piro D, Rejman J, Conese M. Stem cell therapy for cystic fibrosis: current status and future prospects. Expert Rev Respir Med 2010; 2:365-80. [PMID: 20477199 DOI: 10.1586/17476348.2.3.365] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although cystic fibrosis (CF), an autosomal recessive disease caused by mutations in the gene encoding for the CF transmembrane conductance regulator (CFTR), seems a good candidate for gene therapy, 15 years of intense investigation and a number of clinical trials have not yet produced a viable clinical gene-therapy strategy. In addition, the duration of gene expression has been shown to be limited, only lasting 1-4 weeks. Therefore, alternative approaches involve the search for, and use of, stem cell populations. Bone marrow contains different stem cell types, including hematopoietic stem cells and multipotent mesenchymal stromal cells. Numerous studies have now demonstrated the ability of hematopoietic stem cells and mesenchymal stromal cells to home to the lung and differentiate into epithelial cells of both the conducting airways and the alveolar region. However, engraftment of bone marrow-derived stem cells into the airways is a very inefficient process. Detailed knowledge of the cellular and molecular determinants governing homing to the lung and transformation of marrow cells into lung epithelial cells would benefit this process. Despite a very low level of engraftment of donor cells into the nose and gut, significant CFTR mRNA expression and a measurable level of correction of the electrophysiological defect were observed after transplantation of wild-type marrow cells into CF mice. It is uncertain whether this effect is due to the presence of CFTR-expressing epithelial cells derived from donor cells or to the immunomodulatory role of transplanted cells. Finally, initial studies on the usefulness of umbilical cord blood and embryonic stem cells in the generation of airway epithelial cells will be discussed in this review.
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Affiliation(s)
- Donatella Piro
- Department of Biomedical Sciences, University of Foggia, c/o Ospedali Riuniti, Viale L. Pinto 1, 71100 Foggia, Italy.
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131
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Mall MA, Button B, Johannesson B, Zhou Z, Livraghi A, Caldwell RA, Schubert SC, Schultz C, O'Neal WK, Pradervand S, Hummler E, Rossier BC, Grubb BR, Boucher RC. Airway surface liquid volume regulation determines different airway phenotypes in liddle compared with betaENaC-overexpressing mice. J Biol Chem 2010; 285:26945-26955. [PMID: 20566636 DOI: 10.1074/jbc.m110.151803] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Studies in cystic fibrosis patients and mice overexpressing the epithelial Na(+) channel beta-subunit (betaENaC-Tg) suggest that raised airway Na(+) transport and airway surface liquid (ASL) depletion are central to the pathogenesis of cystic fibrosis lung disease. However, patients or mice with Liddle gain-of-function betaENaC mutations exhibit hypertension but no lung disease. To investigate this apparent paradox, we compared the airway phenotype (nasal versus tracheal) of Liddle with CFTR-null, betaENaC-Tg, and double mutant mice. In mouse nasal epithelium, the region that functionally mimics human airways, high levels of CFTR expression inhibited Liddle epithelial Nat channel (ENaC) hyperfunction. Conversely, in mouse trachea, low levels of CFTR failed to suppress Liddle ENaC hyperfunction. Indeed, Na(+) transport measured in Ussing chambers ("flooded" conditions) was raised in both Liddle and betaENaC-Tg mice. Because enhanced Na(+) transport did not correlate with lung disease in these mutant mice, measurements in tracheal cultures under physiologic "thin film" conditions and in vivo were performed. Regulation of ASL volume and ENaC-mediated Na(+) absorption were intact in Liddle but defective in betaENaC-Tg mice. We conclude that the capacity to regulate Na(+) transport and ASL volume, not absolute Na(+) transport rates in Ussing chambers, is the key physiologic function protecting airways from dehydration-induced lung disease.
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Affiliation(s)
- Marcus A Mall
- Division of Pediatric Pulmonology and Cystic Fibrosis Center, Department of Pediatrics III, University of Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany; Molecular Medicine Partnership Unit, University of Heidelberg and European Molecular Biology Laboratory, Im Neuenheimer Feld 350, 69120 Heidelberg, Germany.
| | - Brian Button
- Cystic Fibrosis/Pulmonary Research and Treatment Center, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7248, Switzerland
| | - Bjarki Johannesson
- Division of Pediatric Pulmonology and Cystic Fibrosis Center, Department of Pediatrics III, University of Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany; Molecular Medicine Partnership Unit, University of Heidelberg and European Molecular Biology Laboratory, Im Neuenheimer Feld 350, 69120 Heidelberg, Germany
| | - Zhe Zhou
- Division of Pediatric Pulmonology and Cystic Fibrosis Center, Department of Pediatrics III, University of Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Alessandra Livraghi
- Cystic Fibrosis/Pulmonary Research and Treatment Center, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7248, Switzerland
| | - Ray A Caldwell
- Cystic Fibrosis/Pulmonary Research and Treatment Center, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7248, Switzerland
| | - Susanne C Schubert
- Division of Pediatric Pulmonology and Cystic Fibrosis Center, Department of Pediatrics III, University of Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Carsten Schultz
- Molecular Medicine Partnership Unit, University of Heidelberg and European Molecular Biology Laboratory, Im Neuenheimer Feld 350, 69120 Heidelberg, Germany; Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Wanda K O'Neal
- Cystic Fibrosis/Pulmonary Research and Treatment Center, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7248, Switzerland
| | - Sylvain Pradervand
- Department of Pharmacology and Toxicology, University of Lausanne, Bugnon 27, CH-1005 Lausanne, Switzerland
| | - Edith Hummler
- Department of Pharmacology and Toxicology, University of Lausanne, Bugnon 27, CH-1005 Lausanne, Switzerland
| | - Bernard C Rossier
- Department of Pharmacology and Toxicology, University of Lausanne, Bugnon 27, CH-1005 Lausanne, Switzerland
| | - Barbara R Grubb
- Cystic Fibrosis/Pulmonary Research and Treatment Center, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7248, Switzerland
| | - Richard C Boucher
- Cystic Fibrosis/Pulmonary Research and Treatment Center, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7248, Switzerland
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Namkung W, Finkbeiner WE, Verkman AS. CFTR-adenylyl cyclase I association responsible for UTP activation of CFTR in well-differentiated primary human bronchial cell cultures. Mol Biol Cell 2010; 21:2639-48. [PMID: 20554763 PMCID: PMC2912350 DOI: 10.1091/mbc.e09-12-1004] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Chloride secretion by airway epithelial cells is defective in cystic fibrosis (CF). The conventional paradigm is that CFTR is activated through cAMP and protein kinase A (PKA), whereas the Ca(2+)-activated chloride channel (CaCC) is activated by Ca(2+) agonists like UTP. We found that most chloride current elicited by Ca(2+) agonists in primary cultures of human bronchial epithelial cells is mediated by CFTR by a mechanism involving Ca(2+) activation of adenylyl cyclase I (AC1) and cAMP/PKA signaling. Use of selective inhibitors showed that Ca(2+) agonists produced more chloride secretion from CFTR than from CaCC. CFTR-dependent chloride secretion was reduced by PKA inhibition and was absent in CF cell cultures. Ca(2+) agonists produced cAMP elevation, which was blocked by adenylyl cyclase inhibition. AC1, a Ca(2+)/calmodulin-stimulated adenylyl cyclase, colocalized with CFTR in the cell apical membrane. RNAi knockdown of AC1 selectively reduced UTP-induced cAMP elevation and chloride secretion. These results, together with correlations between cAMP and chloride current, suggest that compartmentalized AC1-CFTR association is responsible for Ca(2+)/cAMP cross-talk. We further conclude that CFTR is the principal chloride secretory pathway in non-CF airways for both cAMP and Ca(2+) agonists, providing a novel mechanism to link CFTR dysfunction to CF lung disease.
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Affiliation(s)
- Wan Namkung
- Department of Medicine and Physiology, University of California, San Francisco, CA 94143, USA
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133
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Respiratory syncytial virus engineered to express the cystic fibrosis transmembrane conductance regulator corrects the bioelectric phenotype of human cystic fibrosis airway epithelium in vitro. J Virol 2010; 84:7770-81. [PMID: 20504917 DOI: 10.1128/jvi.00346-10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Cystic fibrosis (CF) is the most common lethal recessive genetic disease in the Caucasian population. It is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene that is normally expressed in ciliated airway epithelial cells and the submucosal glands of the lung. Since the CFTR gene was first characterized in 1989, a major goal has been to develop an effective gene therapy for CF lung disease, which has the potential to ameliorate morbidity and mortality. Respiratory syncytial virus (RSV) naturally infects the ciliated cells in the human airway epithelium. In addition, the immune response mounted against an RSV infection does not prevent subsequent infections, suggesting that an RSV-based vector might be effectively readministered. To test whether the large 4.5-kb CFTR gene could be expressed by a recombinant RSV and whether infectious virus could be used to deliver CFTR to ciliated airway epithelium derived from CF patients, we inserted the CFTR gene into four sites in a recombinant green fluorescent protein-expressing RSV (rgRSV) genome to generate virus expressing four different levels of CFTR protein. Two of these four rgRSV-CFTR vectors were capable of expressing CFTR with little effect on viral replication. rgRSV-CFTR infection of primary human airway epithelial cultures derived from CF patients resulted in expression of CFTR protein that was properly localized at the luminal surface and corrected the chloride ion channel defect in these cells.
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134
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Kreda SM, Seminario-Vidal L, van Heusden CA, O'Neal W, Jones L, Boucher RC, Lazarowski ER. Receptor-promoted exocytosis of airway epithelial mucin granules containing a spectrum of adenine nucleotides. J Physiol 2010; 588:2255-67. [PMID: 20421285 DOI: 10.1113/jphysiol.2009.186643] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Purinergic regulation of airway innate defence activities is in part achieved by the release of nucleotides from epithelial cells. However, the mechanisms of airway epithelial nucleotide release are poorly understood. We have previously demonstrated that ATP is released from ionomycin-stimulated airway epithelial goblet cells coordinately with mucin exocytosis, suggesting that ATP is released as a co-cargo molecule from mucin-containing granules. We now demonstrate that protease-activated-receptor (PAR) agonists also stimulate the simultaneous release of mucins and ATP from airway epithelial cells. PAR-mediated mucin and ATP release were dependent on intracellular Ca(2+) and actin cytoskeleton reorganization since BAPTA AM, cytochalasin D, and inhibitors of Rho and myosin light chain kinases blocked both responses. To test the hypothesis that ATP is co-released with mucin from mucin granules, we measured the nucleotide composition of isolated mucin granules purified based on their MUC5AC and VAMP-8 content by density gradients. Mucin granules contained ATP, but the levels of ADP and AMP within granules exceeded by nearly 10-fold that of ATP. Consistent with this finding, apical secretions from PAR-stimulated cells contained relatively high levels of ADP/AMP, which could not be accounted for solely based on ATP release and hydrolysis. Thus, mucin granules contribute to ATP release and also are a source of extracellular ADP and AMP. Direct release of ADP/AMP from mucin granules is likely to provide a major source of airway surface adenosine to signal in a paracrine faction ciliated cell A(2b) receptors to activate ion/water secretion and appropriately hydrate goblet cell-released mucins.
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Affiliation(s)
- Silvia M Kreda
- Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, 4029A Thurston Bowles Building, Chapel Hill, NC 27599-7248, USA.
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135
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Alveolar inflammation in cystic fibrosis. J Cyst Fibros 2010; 9:217-27. [PMID: 20347403 DOI: 10.1016/j.jcf.2010.03.001] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 02/08/2010] [Accepted: 03/01/2010] [Indexed: 11/30/2022]
Abstract
BACKGROUND In infected lungs of the cystic fibrosis (CF) patients, opportunistic pathogens and mutated cystic fibrosis transmembrane conductance regulator protein (CFTR) contribute to chronic airway inflammation that is characterized by neutrophil/macrophage infiltration, cytokine release and ceramide accumulation. We sought to investigate CF lung inflammation in the alveoli. METHODS Lung tissue from 14 CF patients and four healthy individuals was analyzed for numbers of effector cells, elastin and collagen concentrations, inflammatory markers and density of Pseudomonas aeruginosa. Additionally, desmosine and isodesmosine concentrations were determined in 52 urine specimens from CF patients to estimate the burden of elastase activities in respiratory secretions. RESULTS Elastin concentration was significantly decreased and collagen significantly increased in CF alveolar tissues as compared to age-matched, healthy individuals. Elastin split products were significantly increased in urine samples from patients with CF and correlated inversely with age, indicating local tissue remodelling due to elastin degradation by unopposed proteolytic enzymes. Alveolar inflammation was also characterized by a significant cell infiltration of neutrophils, macrophages and T cells, extensive nuclear factor-kappaB and insulin-like growth factor-1 activation in various cell types and increased intercellular adhesion molecule-1 expression, and increased numbers of myofibroblasts. Additionally, ceramide accumulated in type II alveolar epithelial cells, lacking CFTR. P. aeruginosa organisms were rarely present in inflamed alveoli. CONCLUSIONS Chronic inflammation and remodeling is present in alveolar tissues of the CF lung and needs to be addressed by anti-inflammatory therapies.
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Excoffon KJDA, Gansemer ND, Mobily ME, Karp PH, Parekh KR, Zabner J. Isoform-specific regulation and localization of the coxsackie and adenovirus receptor in human airway epithelia. PLoS One 2010; 5:e9909. [PMID: 20361046 PMCID: PMC2845650 DOI: 10.1371/journal.pone.0009909] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Accepted: 03/05/2010] [Indexed: 12/25/2022] Open
Abstract
Adenovirus is an important respiratory pathogen. Adenovirus fiber from most serotypes co-opts the Coxsackie-Adenovirus Receptor (CAR) to bind and enter cells. However, CAR is a cell adhesion molecule localized on the basolateral membrane of polarized epithelia. Separation from the lumen of the airways by tight junctions renders airway epithelia resistant to inhaled adenovirus infection. Although a role for CAR in viral spread and egress has been established, the mechanism of initial respiratory infection remains controversial. CAR exists in several protein isoforms including two transmembrane isoforms that differ only at the carboxy-terminus (CAR(Ex7) and CAR(Ex8)). We found low-level expression of the CAR(Ex8) isoform in well-differentiated human airway epithelia. Surprisingly, in contrast to CAR(Ex7), CAR(Ex8) localizes to the apical membrane of epithelia where it augments adenovirus infection. Interestingly, despite sharing a similar class of PDZ-binding domain with CAR(Ex7), CAR(Ex8) differentially interacts with PICK1, PSD-95, and MAGI-1b. MAGI-1b appears to stoichiometrically regulate the degradation of CAR(Ex8) providing a potential mechanism for the apical localization of CAR(Ex8) in airway epithelial. In summary, apical localization of CAR(Ex8) may be responsible for initiation of respiratory adenoviral infections and this localization appears to be regulated by interactions with PDZ-domain containing proteins.
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Affiliation(s)
| | - Nicholas D. Gansemer
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Matthew E. Mobily
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Philip H. Karp
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Kalpaj R. Parekh
- Department of Cardiothoracic Surgery, University of Iowa, Iowa City, Iowa, United States of America
| | - Joseph Zabner
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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Fausther M, Pelletier J, Ribeiro CM, Sévigny J, Picher M. Cystic fibrosis remodels the regulation of purinergic signaling by NTPDase1 (CD39) and NTPDase3. Am J Physiol Lung Cell Mol Physiol 2010; 298:L804-18. [PMID: 20190036 DOI: 10.1152/ajplung.00019.2010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Airway defenses are regulated by a complex purinergic signaling network located on the epithelial surfaces, where ATP stimulates the clearance of mucin and pathogens. The present study shows that the obstructive disease cystic fibrosis (CF) affects the activity, expression, and tissue distribution of two ectonucleotidases found critical for the regulation of ATP on airway surfaces: NTPDase1 and NTPDase3. Functional polarities and mRNA expression levels were determined on primary cultures of human bronchial epithelial (HBE) cells from healthy donors and CF patients. The in vitro model of the disease was completed by exposing CF HBE cultures for 4 days to supernatant of the mucopurulent material (SMM) collected from the airways of CF patients. We report that NTPDase1 and NTPDase3 are coexpressed on HBE cultures, where they regulate physiological and excess nucleotide concentrations, respectively. In aseptic conditions, CF epithelia exhibit >50% lower NTPDase1 activity, protein, and mRNA levels than normal epithelia, whereas these parameters are threefold higher for NTPDase3. Exposure to SMM induced opposite polarity shifts of the two NTPDases on both normal and CF epithelia, apical NTPDase1 being mobilized to basolateral surfaces and bilateral NTPDase3 to the apical surface. Their immunolocalization in human tissue revealed that NTPDase1 is expressed in epithelial, inflammatory, and endothelial cells, whereas NTPDase3 is restricted to epithelial cells. Furthermore, the SMM-exposed CF HBE cultures reproduced the impact of the disease on their in vivo distribution. This study provides evidence that an extensive remodeling of the enzymatic network regulating clearance occurs in the airways of CF patients.
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Affiliation(s)
- Michel Fausther
- Centre de Recherche en Rhumatologie et Immunologie, Université Laval, Ste-Foy, Quebec City, Canada
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138
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Schreiber R, Uliyakina I, Kongsuphol P, Warth R, Mirza M, Martins JR, Kunzelmann K. Expression and function of epithelial anoctamins. J Biol Chem 2010; 285:7838-45. [PMID: 20056604 DOI: 10.1074/jbc.m109.065367] [Citation(s) in RCA: 182] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The calcium-activated chloride channel anoctamin1 (ANO1; TMEM16A) is fundamental for the function of epithelial organs. Mice lacking ANO1 expression exhibit transport defects and a pathology similar to cystic fibrosis. They also show a general defect of epithelial electrolyte transport. Here we analyzed expression of all ten members (ANO1-ANO10) in a broad range of murine tissues and detected predominant expression of ANO1, 6, 7, 8, 9, 10 in epithelial tissues, while ANO2, 3, 4, 5 are common in neuronal and muscle tissues. When expressed in Fisher Rat Thyroid (FTR) cells, all ANO proteins localized to the plasma membrane but only ANO1, 2, 6, and 7 produced Ca(2+)-activated Cl(-) conductance, as analyzed by ATP-induced iodide quenching of YFP fluorescence. In contrast ANO9 and ANO10 suppressed baseline Cl(-) conductance and coexpression of ANO9 with ANO1 inhibited ANO1 activity. Patch clamping of ANO-expressing FRT cells indicated that apart from ANO1 also ANO6 and 10 produced chloride currents, albeit with very different Ca(2+) sensitivity and activation time. We conclude that each tissue expresses a set of anoctamins that form cell- and tissue-specific Ca(2+)-dependent Cl(-) channels.
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Affiliation(s)
- Rainer Schreiber
- Institut für Physiologie, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
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139
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Demmers KJ, Carter D, Fan S, Mao P, Maqbool NJ, McLeod BJ, Bartolo R, Butt AG. Molecular and functional characterization of the cystic fibrosis transmembrane conductance regulator from the Australian common brushtail possum, Trichosurus vulpecula. J Comp Physiol B 2009; 180:545-61. [PMID: 20012660 DOI: 10.1007/s00360-009-0433-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 11/14/2009] [Accepted: 11/19/2009] [Indexed: 02/07/2023]
Abstract
Unlike eutherian mammals, the colon of the Australian common brushtail possum, Trichosurus vulpecula, a metatherian mammal, is incapable of electrogenic Cl(-) secretion and has elevated levels of electrogenic Na(+) absorption, while the ileum secretes HCO (3) (-) rather than Cl(-). In eutherian mammals, the cystic fibrosis transmembrane conductance regulator (CFTR) is essential for both Cl(-) and HCO (3) (-) secretion and the regulation of Na(+) absorption. Therefore, we have sequenced possum (p)CFTR, described its distribution and characterized the properties of cloned pCFTR expressed in Fischer rat thyroid (FRT) cells. pCFTR (GenBank accession No. AY916796) has a 1,478 amino acid open reading frame, which has >90% identity with CFTR from other marsupials and >80% identity with non-rodent eutherian mammals. In pCFTR, there is a high level of conservation of the transmembrane and nucleotide binding domains although, with the exception of other marsupials, there is considerable divergence from other species in the R domain. FRT cells transfected with pCFTR express mature CFTR protein which functions as a small Cl(-) channel activated by cAMP-dependent phosphorylation. In whole-cell recordings it has a linear, time and voltage-independent conductance, with a selectivity sequence P(Br) > P(Cl) > P(I) > P(HCO)(3) >> P(Gluconate). pCFTR transcript is present in a range of epithelia, including the ileum and the colon. The presence of pCFTR in the ileum and its measured HCO (3) (-) permeability suggest that it may be involved in ileal HCO (3) (-) secretion. Why the possum colon does not secrete Cl(-) and has elevated electrogenic Na(+) absorption, despite the apparent expression of CFTR, remains to be determined.
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Affiliation(s)
- K J Demmers
- AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel 9024, New Zealand
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Cholon DM, O'Neal WK, Randell SH, Riordan JR, Gentzsch M. Modulation of endocytic trafficking and apical stability of CFTR in primary human airway epithelial cultures. Am J Physiol Lung Cell Mol Physiol 2009; 298:L304-14. [PMID: 20008117 DOI: 10.1152/ajplung.00016.2009] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
CFTR is a highly regulated apical chloride channel of epithelial cells that is mutated in cystic fibrosis (CF). In this study, we characterized the apical stability and intracellular trafficking of wild-type and mutant CFTR in its native environment, i.e., highly differentiated primary human airway epithelial (HAE) cultures. We labeled the apical pool of CFTR and subsequently visualized the protein in intracellular compartments. CFTR moved from the apical surface to endosomes and then efficiently recycled back to the surface. CFTR endocytosis occurred more slowly in polarized than in nonpolarized HAE cells or in a polarized epithelial cell line. The most common mutation in CF, DeltaF508 CFTR, was rescued from endoplasmic reticulum retention by low-temperature incubation but transited from the apical membrane to endocytic compartments more rapidly and recycled less efficiently than wild-type CFTR. Incubation with small-molecule correctors resulted in DeltaF508 CFTR at the apical membrane but did not restore apical stability. To stabilize the mutant protein at the apical membrane, we found that the dynamin inhibitor Dynasore and the cholesterol-extracting agent cyclodextrin dramatically reduced internalization of DeltaF508, whereas the proteasomal inhibitor MG-132 completely blocked endocytosis of DeltaF508. On examination of intrinsic properties of CFTR that may affect its apical stability, we found that N-linked oligosaccharides were not necessary for transport to the apical membrane but were required for efficient apical recycling and, therefore, influenced the turnover of surface CFTR. Thus apical stability of CFTR in its native environment is affected by properties of the protein and modulation of endocytic trafficking.
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Affiliation(s)
- Deborah M Cholon
- Cystic Fibrosis Research Center and Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7248, USA
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141
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Intronic enhancers coordinate epithelial-specific looping of the active CFTR locus. Proc Natl Acad Sci U S A 2009; 106:19934-9. [PMID: 19897727 DOI: 10.1073/pnas.0900946106] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The regulated expression of large human genes can depend on long-range interactions to establish appropriate three-dimensional structures across the locus. The cystic fibrosis transmembrane conductance regulator (CFTR) gene, which encompasses 189 kb of genomic DNA, shows a complex pattern of expression with both spatial and temporal regulation. The flanking loci, ASZ1 and CTTNBP2, show very different tissue-specific expression. The mechanisms governing control of CFTR expression remain poorly understood, although they are known to involve intronic regulatory elements. Here, we show a complex looped structure of the CFTR locus in cells that express the gene, which is absent from cells in which the gene is inactive. By using chromatin conformation capture (3C) with a bait probe at the CFTR promoter, we demonstrate close interaction of this region with sequences in the middle of the gene about 100 kb from the promoter and with regions 3' to the locus that are about 200 kb away. We show that these interacting regions correspond to prominent DNase I hypersensitive sites within the locus. Moreover, these sequences act cooperatively in reporter gene constructs and recruit proteins that modify chromatin structure. The model for CFTR gene expression that is revealed by our data provides a paradigm for other large genes with multiple regulatory elements lying within both introns and intergenic regions. We anticipate that these observations will enable original approaches to designing regulated transgenes for tissue-specific gene therapy protocols.
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142
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Abstract
The CFTR (cystic fibrosis transmembrane conductance regulator) gene, which when mutated causes cystic fibrosis, encompasses nearly 200 kb of genomic DNA at chromosome 7q31.2. It is flanked by two genes ASZ1 [ankyrin repeat, SAM (sterile alpha-motif) and basic leucine zipper] and CTTNBP2 (cortactin-binding protein 2), which have very different expression profiles. CFTR is expressed primarily in specialized epithelial cells, whereas ASZ1 is transcribed exclusively in the testis and ovary, and CTTNBP2 is highly expressed in the brain, kidney and pancreas, with lower levels of expression in other tissues. Despite its highly regulated pattern of expression, the promoter of the CFTR gene apparently lacks the necessary elements to achieve this. We previously suggested that cis-acting regulatory elements elsewhere in the locus, both flanking the gene and within introns, were required to co-ordinate regulated, tissue-specific expression of CFTR. We identified a number of crucial elements, including enhancer-blocking insulators flanking the locus, intronic tissue-specific enhancers and also characterized some of the interacting proteins. We recently employed a high-resolution method of mapping DHS (DNase I-hypersensitive sites) using tiled microarrays. DHS are often associated with regulatory elements and use of this technique generated cell-specific profiles of potential regulatory sequences in primary cells and cell lines. We characterized a set of cis-acting elements within the CFTR locus and demonstrated direct physical interaction between them and the CFTR promoter, by chromosome conformation capture (3C). These results provide the first insight into the three-dimensional structure of the active CFTR gene.
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143
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CFTR delivery to 25% of surface epithelial cells restores normal rates of mucus transport to human cystic fibrosis airway epithelium. PLoS Biol 2009; 7:e1000155. [PMID: 19621064 PMCID: PMC2705187 DOI: 10.1371/journal.pbio.1000155] [Citation(s) in RCA: 143] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Accepted: 06/11/2009] [Indexed: 12/19/2022] Open
Abstract
Delivering CFTR to ciliated cells of cystic fibrosis (CF) patients fully restores ion and fluid transport to the lumenal surface of airway epithelium and returns mucus transport rates to those of non-CF airways. Dysfunction of CFTR in cystic fibrosis (CF) airway epithelium perturbs the normal regulation of ion transport, leading to a reduced volume of airway surface liquid (ASL), mucus dehydration, decreased mucus transport, and mucus plugging of the airways. CFTR is normally expressed in ciliated epithelial cells of the surface and submucosal gland ductal epithelium and submucosal gland acinar cells. Critical questions for the development of gene transfer strategies for CF airway disease are what airway regions require CFTR function and how many epithelial cells require CFTR expression to restore normal ASL volume regulation and mucus transport to CF airway epithelium? An in vitro model of human CF ciliated surface airway epithelium (CF HAE) was used to test whether a human parainfluenza virus (PIV) vector engineered to express CFTR (PIVCFTR) could deliver sufficient CFTR to CF HAE to restore mucus transport, thus correcting the CF phenotype. PIVCFTR delivered CFTR to >60% of airway surface epithelial cells and expressed CFTR protein in CF HAE approximately 100-fold over endogenous levels in non-CF HAE. This efficiency of CFTR delivery fully corrected the basic bioelectric defects of Cl− and Na+ epithelial ion transport and restored ASL volume regulation and mucus transport to levels approaching those of non-CF HAE. To determine the numbers of CF HAE surface epithelial cells required to express CFTR for restoration of mucus transport to normal levels, different amounts of PIVCFTR were used to express CFTR in 3%–65% of the surface epithelial cells of CF HAE and correlated to increasing ASL volumes and mucus transport rates. These data demonstrate for the first time, to our knowledge, that restoration of normal mucus transport rates in CF HAE was achieved after CFTR delivery to 25% of surface epithelial cells. In vivo experimentation in appropriate models will be required to determine what level of mucus transport will afford clinical benefit to CF patients, but we predict that a future goal for corrective gene transfer to the CF human airways in vivo would attempt to target at least 25% of surface epithelial cells to achieve mucus transport rates comparable to those in non-CF airways. The ciliated epithelium that lines the conducting airways of the lung normally functions to transport hydrated mucus secretions out of the airways to maintain respiratory sterility. Cystic fibrosis (CF) lung disease results from reduced airway surface hydration leading to decreased mucus clearance that precipitates bacterial infection and progressive obstructive lung disease. CF is a genetic disease, and the mutant protein is a chloride ion channel (CFTR) that normally regulates ion and fluid transport on the airway surface. Restoration of corrected CFTR function to the airway epithelium of CF patients by delivering a new CFTR gene to airway epithelial cells has long been envisioned as a therapeutic strategy for CF lung disease. Towards this goal, we use a novel viral vector to deliver CFTR to a culture model that represents the ciliated airway epithelium of CF patients and show that this strategy restores airway surface hydration and mucus transport to levels of that in non-CF individuals. This study demonstrates efficient and efficacious CFTR delivery to CF ciliated airway epithelium and that CFTR delivered to approximately 25% of the surface epithelial cells restores normal levels of airway surface hydration and mucus transport. These studies serve as a benchmark for the efficiency of CFTR gene delivery to CF airways for future CF gene therapy studies in vivo.
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Davidson H, Wilson A, Gray RD, Horsley A, Pringle IA, McLachlan G, Nairn AC, Stearns C, Gibson J, Holder E, Jones L, Doherty A, Coles R, Sumner-Jones SG, Wasowicz M, Manvell M, Griesenbach U, Hyde SC, Gill DR, Davies J, Collie DDS, Alton EWFW, Porteous DJ, Boyd AC. An immunocytochemical assay to detect human CFTR expression following gene transfer. Mol Cell Probes 2009; 23:272-80. [PMID: 19615439 DOI: 10.1016/j.mcp.2009.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 07/02/2009] [Accepted: 07/08/2009] [Indexed: 10/20/2022]
Abstract
BACKGROUND To assess gene therapy treatment for cystic fibrosis (CF) in clinical trials it is essential to develop robust assays that can accurately detect transgene expression in human airway epithelial cells. Our aim was to develop a reproducible immunocytochemical assay for human CFTR protein which can measure both endogenous CFTR levels and augmented CFTR expression after gene delivery. METHODS We characterised an antibody (G449) which satisfied the criteria for use in clinical trials. We optimised our immunocytochemistry method and identified G449 dilutions at which endogenous CFTR levels were negligible in CF samples, thus enhancing detection of transgenic CFTR protein. After developing a transfection technique for brushed human nasal epithelial cells, we transfected non-CF and CF cells with a clinically relevant CpG-free plasmid encoding human CFTR. RESULTS The optimised immunocytochemistry method gave improved discrimination between CF and non-CF samples. Transfection of a CFTR expression vector into primary nasal epithelial cells resulted in detectable RNA and protein expression. CFTR protein was present in 0.05-10% of non-CF cells and 0.02-0.8% of CF cells. CONCLUSION We have developed a sensitive, clinically relevant immunocytochemical assay for CFTR protein and have used it to detect transgene-expressed CFTR in transfected human primary airway epithelial cells.
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Affiliation(s)
- Heather Davidson
- Medical Genetics, School of Molecular and Clinical Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH42XU, UK.
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Bastonero S, Le Priol Y, Armand M, Bernard CS, Reynaud-Gaubert M, Olive D, Parzy D, de Bentzmann S, Capo C, Mege JL. New microbicidal functions of tracheal glands: defective anti-infectious response to Pseudomonas aeruginosa in cystic fibrosis. PLoS One 2009; 4:e5357. [PMID: 19399182 PMCID: PMC2670521 DOI: 10.1371/journal.pone.0005357] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Accepted: 01/14/2009] [Indexed: 12/19/2022] Open
Abstract
Tracheal glands (TG) may play a specific role in the pathogenesis of cystic fibrosis (CF), a disease due to mutations in the cftr gene and characterized by airway inflammation and Pseudomonas aeruginosa infection. We compared the gene expression of wild-type TG cells and TG cells with the cftr DeltaF508 mutation (CF-TG cells) using microarrays covering the whole human genome. In the absence of infection, CF-TG cells constitutively exhibited an inflammatory signature, including genes that encode molecules such as IL-1alpha, IL-beta, IL-32, TNFSF14, LIF, CXCL1 and PLAU. In response to P. aeruginosa, genes associated with IFN-gamma response to infection (CXCL10, IL-24, IFNgammaR2) and other mediators of anti-infectious responses (CSF2, MMP1, MMP3, TLR2, S100 calcium-binding proteins A) were markedly up-regulated in wild-type TG cells. This microbicidal signature was silent in CF-TG cells. The deficiency of genes associated with IFN-gamma response was accompanied by the defective membrane expression of IFNgammaR2 and altered response of CF-TG cells to exogenous IFN-gamma. In addition, CF-TG cells were unable to secrete CXCL10, IL-24 and S100A8/S100A9 in response to P. aeruginosa. The differences between wild-type TG and CF-TG cells were due to the cftr mutation since gene expression was similar in wild-type TG cells and CF-TG cells transfected with a plasmid containing a functional cftr gene. Finally, we reported an altered sphingolipid metabolism in CF-TG cells, which may account for their inflammatory signature. This first comprehensive analysis of gene expression in TG cells proposes a protective role of wild-type TG against airborne pathogens and reveals an original program in which anti-infectious response was deficient in TG cells with a cftr mutation. This defective response may explain why host response does not contribute to protection against P. aeruginosa in CF.
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Affiliation(s)
- Sonia Bastonero
- Unité de Recherche sur les Maladies Infectieuses Tropicales et Emergentes, CNRS UMR 6236, Faculté de Médecine, Marseille, France
| | - Yannick Le Priol
- Transcriptomic platform, Institut de Médecine Tropicale du Service de Santé des Armées, Marseille, France
| | - Martine Armand
- UMR Nutriments Lipidiques et Prévention des Maladies Métaboliques, INSERM U476 INRA UMR1260, Faculté de Médecine, Marseille, France
| | - Christophe S. Bernard
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS-IMM-UPR 9027, Marseille, France
| | | | - Daniel Olive
- Institut Paoli Calmettes, INSERM Unité 891, Centre de Recherche en Cancérologie, Marseille, France
| | - Daniel Parzy
- Transcriptomic platform, Institut de Médecine Tropicale du Service de Santé des Armées, Marseille, France
| | - Sophie de Bentzmann
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS-IMM-UPR 9027, Marseille, France
| | - Christian Capo
- Unité de Recherche sur les Maladies Infectieuses Tropicales et Emergentes, CNRS UMR 6236, Faculté de Médecine, Marseille, France
| | - Jean-Louis Mege
- Unité de Recherche sur les Maladies Infectieuses Tropicales et Emergentes, CNRS UMR 6236, Faculté de Médecine, Marseille, France
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146
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Choi JY, Khansaheb M, Joo NS, Krouse ME, Robbins RC, Weill D, Wine JJ. Substance P stimulates human airway submucosal gland secretion mainly via a CFTR-dependent process. J Clin Invest 2009; 119:1189-200. [PMID: 19381016 DOI: 10.1172/jci37284] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Accepted: 02/25/2009] [Indexed: 11/17/2022] Open
Abstract
Chronic bacterial airway infections are the major cause of mortality in cystic fibrosis (CF). Normal airway defenses include reflex stimulation of submucosal gland mucus secretion by sensory neurons that release substance P (SubP). CFTR is an anion channel involved in fluid secretion and mutated in CF; the role of CFTR in secretions stimulated by SubP is unknown. We used optical methods to measure SubP-mediated secretion from human submucosal glands in lung transplant tissue. Glands from control but not CF subjects responded to mucosal chili oil. Similarly, serosal SubP stimulated secretion in more than 60% of control glands but only 4% of CF glands. Secretion triggered by SubP was synergistic with vasoactive intestinal peptide and/or forskolin but not with carbachol; synergy was absent in CF glands. Pig glands demonstrated a nearly 10-fold greater response to SubP. In 10 of 11 control glands isolated by fine dissection, SubP caused cell volume loss, lumen expansion, and mucus flow, but in 3 of 4 CF glands, it induced lumen narrowing. Thus, in CF, the reduced ability of mucosal irritants to stimulate airway gland secretion via SubP may be another factor that predisposes the airways to infections.
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147
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Collawn JF, Bebok Z, Matalon S. Search and rescue: finding ways to correct deltaF508 CFTR. Am J Respir Cell Mol Biol 2009; 40:385-7. [PMID: 19293344 DOI: 10.1165/rcmb.2008-0006ed] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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148
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Grubb BR, Rogers TD, Boucher RC, Ostrowski LE. Ion transport across CF and normal murine olfactory and ciliated epithelium. Am J Physiol Cell Physiol 2009; 296:C1301-9. [PMID: 19321738 DOI: 10.1152/ajpcell.00578.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The nasal epithelium of the cystic fibrosis (CF) mouse has been used extensively in CF research because it exhibits ion transport defects similar to those of human CF airways. This tissue is composed of approximately 50% olfactory (OE) and approximately 50% ciliated epithelium (CE), and on the basis of previous observations, we hypothesized that a significant fraction of the bioelectric signals from murine nasal tissue may arise from OE rather than CE, while CE is the target tissue for CF gene therapy. We compared the bioelectric properties of isolated OE from the nasal cavity and CE from the nasopharynx in Ussing chamber studies. Hyperabsorption of Na(+) [amiloride response; CF vs. wild type (WT)] was approximately 7.5-fold greater in the OE compared with the CE. The forskolin response in native tissues did not reliably distinguish genotypes, likely due to a cyclic nucleotide-gated cation conductance in OE and a calcium-mediated Cl(-) conductance in CE. By potential difference assay, hyperabsorption of Na(+) (CF vs. WT) and the difference in response to apical 0 Cl(-) buffer (CF vs. WT) were approximately 2-fold greater in the nasal cavity compared with the nasopharynx. Our studies demonstrate that in the CF mouse, both the hyperabsorption of Na(+) and the Cl(-) transport defect are of larger magnitude in the OE than in the CE. Thus, while the murine CF nasal epithelium is a valuable model for CF studies, the bioelectrics are likely dominated by the signals from the OE, and assays of the nasopharynx may be more specific for studying the ciliated epithelium.
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Affiliation(s)
- B R Grubb
- Cystic Fibrosis/Pulmonary Research and Treatment Center, 7011 Thurston-Bowles Bldg., CB 7248, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolia 27599-7248, USA.
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149
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Fouassier L, Rosenberg P, Mergey M, Saubaméa B, Clapéron A, Kinnman N, Chignard N, Jacobsson-Ekman G, Strandvik B, Rey C, Barbu V, Hultcrantz R, Housset C. Ezrin-radixin-moesin-binding phosphoprotein (EBP50), an estrogen-inducible scaffold protein, contributes to biliary epithelial cell proliferation. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 174:869-80. [PMID: 19234136 DOI: 10.2353/ajpath.2009.080079] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) anchors and regulates apical membrane proteins in epithelia. EBP50 is inducible by estrogen and may affect cell proliferation, although this latter function remains unclear. The goal of this study was to determine whether EBP50 was implicated in the ductular reaction that occurs in liver disease. EBP50 expression was examined in normal human liver, in human cholangiopathies (ie, cystic fibrosis, primary biliary cirrhosis, and primary sclerosing cholangitis), and in rats subjected to bile-duct ligation. The regulation of EBP50 by estrogens and its impact on proliferation were assessed in both bile duct-ligated rats and Mz-Cha-1 human biliary epithelial cells. Analyses of cell isolates and immunohistochemical studies showed that in normal human liver, EBP50 is expressed in the canalicular membranes of hepatocytes and, together with ezrin and cystic fibrosis transmembrane conductance regulator, in the apical domains of cholangiocytes. In both human cholangiopathies and bile duct-ligated rats, EBP50 was redistributed to the cytoplasmic and nuclear compartments. EBP50 underwent a transient increase in rat cholangiocytes after bile-duct ligation, whereas such expression was down-regulated in ovariectomized rats. In addition, in Mz-Cha-1 cells, EBP50 underwent up-regulation and intracellular redistribution in response to 17beta-estradiol, whereas its proliferation was inhibited by siRNA-mediated EBP50 knockdown. These results indicate that both the expression and distribution of EBP50 are regulated by estrogens and contribute to the proliferative response in biliary epithelial cells.
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Affiliation(s)
- Laura Fouassier
- INSERM, UMR_S 893, CdR Saint-Antoine, Faculté de Médecine Pierre et Marie Curie, site Saint-Antoine, 27, rue Chaligny, 75571 Paris cedex 12, France.
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150
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Joo NS, Wine JJ, Cuthbert AW. Lubiprostone stimulates secretion from tracheal submucosal glands of sheep, pigs, and humans. Am J Physiol Lung Cell Mol Physiol 2009; 296:L811-24. [PMID: 19233902 DOI: 10.1152/ajplung.90636.2008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Lubiprostone, a putative ClC-2 chloride channel opener, has been investigated for its effects on airway epithelia (tracheas). Lubiprostone is shown to increase submucosal gland secretion in pigs, sheep, and humans and to increase short-circuit current (SCC) in the surface epithelium of pigs and sheep. Use of appropriate blocking agents and ion-substitution experiments shows anion secretion is the driving force for fluid formation in both glands and surface epithelium. From SCC concentration-response relations, it is shown that for apical lubiprostone K(d) = 10.5 nM with a Hill slope of 1.08, suggesting a single type of binding site and, from the speed of the response, close to the apical surface, confirmed the rapid blockade by Cd ions. Responses to lubiprostone were reversible and repeatable, responses being significantly larger with ventral compared with dorsal epithelium. Submucosal gland secretion rates following basolateral lubiprostone were, respectively, 0.2, 0.5, and 0.8 nl gl(-1) min(-1) in humans, sheep, and pigs. These rates dwarf any contribution surface secretion adds to the accumulation of surface liquid under the influence of lubiprostone. Lubiprostone stimulated gland secretion in two out of four human cystic fibrosis (CF) tissues and in two of three disease controls, chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis (COPD/IPF), but in neither type of tissue was the increase significant. Lubiprostone was able to increase gland secretion rates in normal human tissue in the continuing presence of a high forskolin concentration. Lubiprostone had no spasmogenic activity on trachealis muscle, making it a potential agent for increasing airway secretion that may have therapeutic utility.
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Affiliation(s)
- N S Joo
- Department of Medicine, University of Cambridge, Cambridge CB2 2QQ, UK
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