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Tanjala AC, Jiang JX, Eckford PDW, Ramjeesingh M, Li C, Huan LJ, Langeveld G, Townsend C, Paone DV, Busch-Petersen J, Pekhletski R, Tang L, Raju V, Rowe SM, Bear CE. Comparison of a novel potentiator of CFTR channel activity to ivacaftor in ameliorating mucostasis caused by cigarette smoke in primary human bronchial airway epithelial cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.01.582742. [PMID: 38496440 PMCID: PMC10942391 DOI: 10.1101/2024.03.01.582742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Background Cystic Fibrosis causing mutations in the gene CFTR , reduce the activity of the CFTR channel protein, and leads to mucus aggregation, airway obstruction and poor lung function. A role for CFTR in the pathogenesis of other muco-obstructive airway diseases such as Chronic Obstructive Pulmonary Disease (COPD) has been well established. The CFTR modulatory compound, Ivacaftor (VX-770), potentiates channel activity of CFTR and certain CF-causing mutations and has been shown to ameliorate mucus obstruction and improve lung function in people harbouring these CF-causing mutations. A pilot trial of Ivacaftor supported its potential efficacy for the treatment of mucus obstruction in COPD. These findings prompted the search for CFTR potentiators that are more effective in ameliorating cigarette-smoke (CS) induced mucostasis. Methods A novel small molecule potentiator (SK-POT1), previously identified in CFTR binding studies, was tested for its activity in augmenting CFTR channel activity using patch clamp electrophysiology in HEK-293 cells, a fluorescence-based assay of membrane potential in Calu-3 cells and in Ussing chamber studies of primary bronchial epithelial cultures. Addition of cigarette smoke extract (CSE) to the solutions bathing the apical surface of Calu-3 cells and primary bronchial airway cultures was used to model COPD. Confocal studies of the velocity of fluorescent microsphere movement on the apical surface of CSE exposed airway epithelial cultures, were used to assess the effect of potentiators on CFTR-mediated mucociliary movement. Results We showed that SK-POT1, like VX-770, was effective in augmenting the cyclic AMP-dependent channel activity of CFTR. SK-POT-1 enhanced CFTR channel activity in airway epithelial cells previously exposed to CSE and ameliorated mucostasis on the surface of primary airway cultures. Conclusion Together, this evidence supports the further development of SK-POT1 as an intervention in the treatment of COPD.
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Boyne K, Corey DA, Zhao P, Lu B, Boron WF, Moss FJ, Kelley TJ. Carbonic anhydrase and soluble adenylate cyclase regulation of cystic fibrosis cellular phenotypes. Am J Physiol Lung Cell Mol Physiol 2022; 322:L333-L347. [PMID: 34986321 PMCID: PMC8858677 DOI: 10.1152/ajplung.00022.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Several aspects of the cell biology of cystic fibrosis (CF) epithelial cells are altered including impaired lipid regulation, disrupted intracellular transport, and impaired microtubule regulation. It is unclear how the loss of cystic fibrosis transmembrane conductance regulator (CFTR) function leads to these differences. It is hypothesized that the loss of CFTR function leads to altered regulation of carbonic anhydrase (CA) activity resulting in cellular phenotypic changes. In this study, it is demonstrated that CA2 protein expression is reduced in CF model cells, primary mouse nasal epithelial (MNE) cells, excised MNE tissue, and primary human nasal epithelial cells (P < 0.05). This corresponds to a decrease in CA2 RNA expression measured by qPCR as well as an overall reduction in CA activity in primary CF MNEs. The addition of CFTR-inhibitor-172 to WT MNE cells for ≥24 h mimics the significantly lower protein expression of CA2 in CF cells. Treatment of CF cells with l-phenylalanine (L-Phe), an activator of CA activity, restores endosomal transport through an effect on microtubule regulation in a manner dependent on soluble adenylate cyclase (sAC). This effect can be blocked with the CA2-selective inhibitor dorzolamide. These data suggest that the loss of CFTR function leads to the decreased expression of CA2 resulting in the downstream cell signaling alterations observed in CF.
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Affiliation(s)
- Kathleen Boyne
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Ann and Robert H. Lurie Children's Hospital of Chicago, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States
| | - Deborah A Corey
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, United States
| | - Pan Zhao
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, United States
| | - Binyu Lu
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, United States
| | - Walter F Boron
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, United States.,Department of Medicine and Department of Biochemistry, Case Western Reserve University, Cleveland, OH, United States
| | - Fraser J Moss
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, United States
| | - Thomas J Kelley
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, United States
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3
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Zhu K, Jin Y. Case report: A case of SLC26A4 mutations causing pendred syndrome and non-cystic fibrosis bronchiectasis. Front Pediatr 2022; 10:1077878. [PMID: 36699303 PMCID: PMC9869259 DOI: 10.3389/fped.2022.1077878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Accepted: 12/06/2022] [Indexed: 01/12/2023] Open
Abstract
The SLC26A4 gene encodes the transmembrane protein pendrin, which is involved in the ion transport of chloride (Cl-), iodide (I-) or bicarbonate (HCO3-). Mutations in the SLC26A4 gene alter the structure and (or) function of pendrin, which are closely related to Pendred syndrome. What's more, researchers have demonstrated in vitro that mutations of SLC26A4 cause acidification of airway surface fluid (ASL), reduce airway defense, and increase the thickness of ASL. In the context of infection, it may lead to chronic inflammation, destruction of airway wall architecture and bronchiectasis. However, there is no case report of bronchiectasis caused by SLC26A4 gene mutations. Here, we describe the first case of Pendred syndrome and non-cystic fibrosis bronchiectasis in a child possibly caused by SLC26A4 mutations. We remind clinicians to pay attention to the possibility of bronchiectasis in patients with SLC26A4 gene mutations.
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Affiliation(s)
- Kang Zhu
- Department of Respiratory, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Yingkang Jin
- Department of Respiratory, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
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4
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Aritake H, Tamada T, Murakami K, Gamo S, Nara M, Kazama I, Ichinose M, Sugiura H. Effects of indacaterol on the LPS-evoked changes in fluid secretion rate and pH in swine tracheal membrane. Pflugers Arch 2021; 473:883-896. [PMID: 34031755 PMCID: PMC8164627 DOI: 10.1007/s00424-021-02560-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 03/16/2021] [Accepted: 03/23/2021] [Indexed: 11/21/2022]
Abstract
An acquired dysregulation of airway secretion is likely involved in the pathophysiology of chronic bronchitis and chronic obstructive pulmonary disease (COPD). Nowadays, it is widely known that several kinds of long-acting bronchodilators reduce the frequency of COPD exacerbations. However, limited data are available concerning the complementary additive effects on airflow obstruction. Using an optical method and a selective pH indicator, we succeeded in evaluating the gland secretion rate and the pH in swine tracheal membrane. A physiologically relevant concentration of acetylcholine (ACh) 100 nM induced a gradual increase in the amount of gland secretion. Lipopolysaccharides (LPS) accelerated the ACh-induced secretory responses up to around threefold and lowered the pH level significantly. Long-acting β2-agonists (LABAs) including indacaterol (IND), formoterol, and salmeterol restored the LPS-induced changes in both the hypersecretion and acidification. The subsequent addition of the long-acting muscarine antagonist, glycopyrronium, further increased the pH values. Two different inhibitors for cystic fibrosis transmembrane conductance regulator (CFTR), NPPB and CFTRinh172, abolished the IND-mediated pH normalization in the presence of both ACh and ACh + LPS. Both immunofluorescence staining and western blotting analysis revealed that LPS downregulated the abundant expression of CFTR protein. However, IND did not restore the LPS-induced decrease in CFTR expression on Calu-3 cells. These findings suggest that the activation of cAMP-dependent HCO3− secretion through CFTR would be partly involved in the IND-mediated pH normalization in gland secretion and may be suitable for the maintenance of airway defense against exacerbating factors including LPS.
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Affiliation(s)
- Hidemi Aritake
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Tsutomu Tamada
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.
| | - Koji Murakami
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Shunichi Gamo
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Masayuki Nara
- National Hospital Organization Akita National Hospital, Yurihonjo, Japan
| | - Itsuro Kazama
- Miyagi University School of Nursing Graduate School of Nursing, Kurokawa-gun, Japan
| | | | - Hisatoshi Sugiura
- Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
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5
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Dabaghi M, Saraei N, Xu G, Chandiramohan A, Yeung J, Nguyen JP, Vukmirovic M, Selvaganapathy PR, Hirota JA. PHAIR: a biosensor for pH measurement in air-liquid interface cell culture. Sci Rep 2021; 11:3477. [PMID: 33568708 PMCID: PMC7875988 DOI: 10.1038/s41598-021-83189-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 01/28/2021] [Indexed: 01/30/2023] Open
Abstract
In many biological systems, pH can be used as a parameter to understand and study cell dynamics. However, measuring pH in live cell culture is limited by the sensor ion specificity, proximity to the cell surface, and scalability. Commercially available pH sensors are difficult to integrate into a small-scale cell culture system due to their size and are not cost-effective for disposable use. We made PHAIR-a new pH sensor that uses a micro-wire format to measure pH in vitro human airway cell culture. Tungsten micro-wires were used as the working electrodes, and silver micro-wires with a silver/silver chloride coating were used as a pseudo reference electrode. pH sensitivity, in a wide and narrow range, and stability of these sensors were tested in common standard buffer solutions as well as in culture media of human airway epithelial cells grown at the air-liquid interface in a 24 well cell culture plate. When measuring the pH of cells grown under basal and challenge conditions using PHAIR, cell viability and cytokine responses were not affected. Our results confirm that micro-wire-based sensors have the capacity for miniaturization and detection of diverse ions while maintaining sensitivity. This suggests the broad application of PHAIR in various biological experimental settings.
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Affiliation(s)
- Mohammadhossein Dabaghi
- Firestone Institute for Respiratory Health-Division of Respirology, Department of Medicine, McMaster University, Hamilton, ON, L8N 4A6, Canada
| | - Neda Saraei
- Firestone Institute for Respiratory Health-Division of Respirology, Department of Medicine, McMaster University, Hamilton, ON, L8N 4A6, Canada
| | - Gang Xu
- Firestone Institute for Respiratory Health-Division of Respirology, Department of Medicine, McMaster University, Hamilton, ON, L8N 4A6, Canada
| | - Abiram Chandiramohan
- Firestone Institute for Respiratory Health-Division of Respirology, Department of Medicine, McMaster University, Hamilton, ON, L8N 4A6, Canada
| | - Jonas Yeung
- Department of Mechanical Engineering, McMaster University, Hamilton, ON, L8S 4L7, Canada
| | - Jenny P Nguyen
- Firestone Institute for Respiratory Health-Division of Respirology, Department of Medicine, McMaster University, Hamilton, ON, L8N 4A6, Canada
| | - Milica Vukmirovic
- Firestone Institute for Respiratory Health-Division of Respirology, Department of Medicine, McMaster University, Hamilton, ON, L8N 4A6, Canada
| | - Ponnambalam Ravi Selvaganapathy
- Department of Mechanical Engineering, McMaster University, Hamilton, ON, L8S 4L7, Canada
- School of Biomedical Engineering, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Jeremy A Hirota
- Firestone Institute for Respiratory Health-Division of Respirology, Department of Medicine, McMaster University, Hamilton, ON, L8N 4A6, Canada.
- School of Biomedical Engineering, McMaster University, Hamilton, ON, L8S 4K1, Canada.
- Department of Pathology and Molecular Medicine, McMaster Immunology Research Centre, McMaster University, Hamilton, ON, L8S 4K1, Canada.
- Division of Respiratory Medicine, Department of Medicine, University of British Columbia, Vancouver, BC, V6H 3Z6, Canada.
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
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6
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McMahon DB, Carey RM, Kohanski MA, Tong CCL, Papagiannopoulos P, Adappa ND, Palmer JN, Lee RJ. Neuropeptide regulation of secretion and inflammation in human airway gland serous cells. Eur Respir J 2020; 55:13993003.01386-2019. [PMID: 32029445 DOI: 10.1183/13993003.01386-2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 01/13/2020] [Indexed: 12/14/2022]
Abstract
Airway submucosal gland serous cells are sites of expression of the cystic fibrosis transmembrane conductance regulator (CFTR) and are important for fluid secretion in conducting airways. To elucidate how neuropeptides regulate serous cells, we tested if human nasal turbinate serous cells secrete bicarbonate (HCO3 -), important for mucus polymerisation and antimicrobial peptide function, during stimulation with cAMP-elevating vasoactive intestinal peptide (VIP) and if this requires CFTR. Serous cells stimulated with VIP exhibited a ∼15-20% cAMP-dependent decrease in cell volume and a ∼0.15 unit decrease in intracellular pH (pHi), reflecting activation of Cl- and HCO3 - secretion, respectively. HCO3 - secretion was directly dependent on CFTR and was absent in cells from CF patients. In contrast, neuropeptide Y (NPY) reduced VIP-evoked cAMP increases, CFTR activation, and Cl-/HCO3 - secretion. Culture of primary serous cells in a model that maintained a serous phenotype confirmed the activating and inhibiting effects of VIP and NPY, respectively, on fluid and HCO3 - secretion. Moreover, VIP enhanced antimicrobial peptide secretion and antimicrobial efficacy of secretions while NPY reduced antimicrobial efficacy. In contrast, NPY enhanced cytokine release while VIP reduced cytokine release through a mechanism requiring CFTR. As levels of VIP and NPY are up-regulated in diseases like allergy, asthma, and chronic rhinosinusitis, the balance of these two peptides in the airway may control mucus rheology and inflammatory responses in serous cells. Furthermore, the loss of CFTR conductance in serous cells may contribute to CF pathophysiology by increasing serous cells inflammatory responses in addition to directly impairing Cl- and HCO3 - secretion.
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Affiliation(s)
- Derek B McMahon
- Dept of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Ryan M Carey
- Dept of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Michael A Kohanski
- Dept of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Charles C L Tong
- Dept of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Peter Papagiannopoulos
- Dept of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Nithin D Adappa
- Dept of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - James N Palmer
- Dept of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Robert J Lee
- Dept of Otorhinolaryngology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.,Dept of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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7
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Kim D, Huang J, Billet A, Abu-Arish A, Goepp J, Matthes E, Tewfik MA, Frenkiel S, Hanrahan JW. Pendrin Mediates Bicarbonate Secretion and Enhances Cystic Fibrosis Transmembrane Conductance Regulator Function in Airway Surface Epithelia. Am J Respir Cell Mol Biol 2020; 60:705-716. [PMID: 30742493 DOI: 10.1165/rcmb.2018-0158oc] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Bicarbonate facilitates mucin unpacking and bacterial killing; however, its transport mechanisms in the airways are not well understood. cAMP stimulates anion efflux through the cystic fibrosis (CF) transmembrane conductance regulator (CFTR; ABCC7) anion channel, and this is defective in CF. The anion exchanger pendrin (SLC26A4) also mediates HCO3- efflux and is upregulated by proinflammatory cytokines. Here, we examined pendrin and CFTR expression and their contributions to HCO3- secretion by human nasal and bronchial epithelia. In native tissue, both proteins were most abundant at the apical pole of ciliated surface cells with little expression in submucosal glands. In well-differentiated primary nasal and bronchial cell cultures, IL-4 dramatically increased pendrin mRNA levels and apical immunostaining. Exposure to low-Cl- apical solution caused intracellular alkalinization (ΔpHi) that was enhanced fourfold by IL-4 pretreatment. ΔpHi was unaffected by 4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid (DIDS) or CFTR inhibitor CFTRinh-172, but was reduced by adenoviral shRNA targeting pendrin. Forskolin increased ΔpHi, and this stimulation was prevented by CFTRinh-172, implicating CFTR, yet forskolin only increased ΔpHi after pendrin expression had been induced by IL-4. The dependence of ΔpHi on pendrin suggests there is minimal electrical coupling between Cl- and HCO3- fluxes and that CFTR activation increases anion exchange-mediated HCO3- influx. Conversely, inducing pendrin expression increased forskolin-stimulated, CFTRinh-172-sensitive current by approximately twofold in epithelial and nonepithelial cells. We conclude that pendrin mediates most HCO3- secretion across airway surface epithelium during inflammation and enhances electrogenic Cl- secretion via CFTR, as described for other SLC26A transporters.
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Affiliation(s)
- Dusik Kim
- 1 Department of Physiology and.,2 Cystic Fibrosis Translational Research Centre, McGill University, Montréal, Québec, Canada; and
| | - Junwei Huang
- 1 Department of Physiology and.,2 Cystic Fibrosis Translational Research Centre, McGill University, Montréal, Québec, Canada; and
| | - Arnaud Billet
- 1 Department of Physiology and.,2 Cystic Fibrosis Translational Research Centre, McGill University, Montréal, Québec, Canada; and
| | - Asmahan Abu-Arish
- 1 Department of Physiology and.,2 Cystic Fibrosis Translational Research Centre, McGill University, Montréal, Québec, Canada; and
| | - Julie Goepp
- 1 Department of Physiology and.,2 Cystic Fibrosis Translational Research Centre, McGill University, Montréal, Québec, Canada; and
| | - Elizabeth Matthes
- 1 Department of Physiology and.,2 Cystic Fibrosis Translational Research Centre, McGill University, Montréal, Québec, Canada; and
| | - Marc A Tewfik
- 2 Cystic Fibrosis Translational Research Centre, McGill University, Montréal, Québec, Canada; and.,3 Department of Otolaryngology-Head and Neck Surgery and
| | - Saul Frenkiel
- 2 Cystic Fibrosis Translational Research Centre, McGill University, Montréal, Québec, Canada; and.,3 Department of Otolaryngology-Head and Neck Surgery and
| | - John W Hanrahan
- 1 Department of Physiology and.,2 Cystic Fibrosis Translational Research Centre, McGill University, Montréal, Québec, Canada; and.,4 Research Institute, McGill University Health Centre, Montréal, Québec, Canada
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8
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Rubenstein RC. Editorial Focus: CFTR-dependent bicarbonate secretion by Calu-3 cells. Physiol Rep 2019; 6:e13691. [PMID: 29845767 PMCID: PMC5974715 DOI: 10.14814/phy2.13691] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Affiliation(s)
- Ronald C Rubenstein
- Division of Pulmonary Medicine and Cystic Fibrosis Center, The Children's Hospital of Philadelphia, Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
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9
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Airway surface liquid acidification initiates host defense abnormalities in Cystic Fibrosis. Sci Rep 2019; 9:6516. [PMID: 31019198 PMCID: PMC6482305 DOI: 10.1038/s41598-019-42751-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 04/03/2019] [Indexed: 12/14/2022] Open
Abstract
Cystic fibrosis (CF) is caused by defective Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein. Morbidity is mainly due to early airway infection. We hypothesized that S. aureus clearance during the first hours of infection was impaired in CF human Airway Surface Liquid (ASL) because of a lowered pH. The ASL pH of human bronchial epithelial cell lines and primary respiratory cells from healthy controls (WT) and patients with CF was measured with a pH microelectrode. The antimicrobial capacity of airway cells was studied after S. aureus apical infection by counting surviving bacteria. ASL was significantly more acidic in CF than in WT respiratory cells. This was consistent with a defect in bicarbonate secretion involving CFTR and SLC26A4 (pendrin) and a persistent proton secretion by ATP12A. ASL demonstrated a defect in S. aureus clearance which was improved by pH normalization. Pendrin inhibition in WT airways recapitulated the CF airway defect and increased S. aureus proliferation. ATP12A inhibition by ouabain decreased bacterial proliferation. Antimicrobial peptides LL-37 and hBD1 demonstrated a pH-dependent activity. Normalizing ASL pH might improve innate airway defense in newborns with CF during onset of S. aureus infection. Pendrin activation and ATP12A inhibition could represent novel therapeutic strategies to normalize pH in CF airways.
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10
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cAMP Stimulates SLC26A3 Activity in Human Colon by a CFTR-Dependent Mechanism That Does Not Require CFTR Activity. Cell Mol Gastroenterol Hepatol 2019; 7:641-653. [PMID: 30659943 PMCID: PMC6438990 DOI: 10.1016/j.jcmgh.2019.01.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 01/07/2019] [Accepted: 01/07/2019] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS SLC26A3 (DRA) is an electroneutral Cl-/HCO3- exchanger that is present in the apical domain of multiple intestinal segments. An area that has continued to be poorly understood is related to DRA regulation in acute adenosine 3',5'-cyclic monophosphate (cAMP)-related diarrheas, in which DRA appears to be both inhibited as part of NaCl absorption and stimulated to contribute to increased HCO3- secretion. Different cell models expressing DRA have shown that cAMP inhibits, stimulates, or does not affect its activity. METHODS This study re-evaluated cAMP regulation of DRA using new tools, including a successful knockout cell model, a specific DRA inhibitor (DRAinh-A250), specific antibodies, and a transport assay that did not rely on nonspecific inhibitors. The studies compared DRA regulation in colonoids made from normal human colon with regulation in the colon cancer cell line, Caco-2. RESULTS DRA is an apical protein in human proximal colon, differentiated colonoid monolayers, and Caco-2 cells. It is glycosylated and appears as 2 bands. cAMP (forskolin) acutely stimulated DRA activity in human colonoids and Caco-2 cells. In these cells, DRA is the predominant apical Cl-/HCO3- exchanger and is inhibited by DRAinh-A250 with a median inhibitory concentration of 0.5 and 0.2 μmol/L, respectively. However, there was no effect of cAMP in HEK293/DRA cells that lacked a cystic fibrosis transmembrane conductance regulator (CFTR). When CFTR was expressed in HEK293/DRA cells, cAMP also stimulated DRA activity. In all cases, cAMP stimulation of DRA was not inhibited by CFTRinh-172. CONCLUSIONS DRA is acutely stimulated by cAMP by a process that is CFTR-dependent, but appears to be one of multiple regulatory effects of CFTR that does not require CFTR activity.
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Castellani S, Di Gioia S, di Toma L, Conese M. Human Cellular Models for the Investigation of Lung Inflammation and Mucus Production in Cystic Fibrosis. Anal Cell Pathol (Amst) 2018; 2018:3839803. [PMID: 30581723 PMCID: PMC6276497 DOI: 10.1155/2018/3839803] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 09/04/2018] [Accepted: 09/23/2018] [Indexed: 12/12/2022] Open
Abstract
Chronic inflammation, oxidative stress, mucus plugging, airway remodeling, and respiratory infections are the hallmarks of the cystic fibrosis (CF) lung disease. The airway epithelium is central in the innate immune responses to pathogens colonizing the airways, since it is involved in mucociliary clearance, senses the presence of pathogens, elicits an inflammatory response, orchestrates adaptive immunity, and activates mesenchymal cells. In this review, we focus on cellular models of the human CF airway epithelium that have been used for studying mucus production, inflammatory response, and airway remodeling, with particular reference to two- and three-dimensional cultures that better recapitulate the native airway epithelium. Cocultures of airway epithelial cells, macrophages, dendritic cells, and fibroblasts are instrumental in disease modeling, drug discovery, and identification of novel therapeutic targets. Nevertheless, they have to be implemented in the CF field yet. Finally, novel systems hijacking on tissue engineering, including three-dimensional cocultures, decellularized lungs, microfluidic devices, and lung organoids formed in bioreactors, will lead the generation of relevant human preclinical respiratory models a step forward.
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Affiliation(s)
- Stefano Castellani
- Laboratory of Regenerative and Experimental Medicine, Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy
| | - Sante Di Gioia
- Laboratory of Regenerative and Experimental Medicine, Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy
| | - Lorena di Toma
- Laboratory of Regenerative and Experimental Medicine, Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy
| | - Massimo Conese
- Laboratory of Regenerative and Experimental Medicine, Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy
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12
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Massip-Copiz MM, Santa-Coloma TA. Extracellular pH and lung infections in cystic fibrosis. Eur J Cell Biol 2018; 97:402-410. [PMID: 29933921 DOI: 10.1016/j.ejcb.2018.06.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 06/01/2018] [Accepted: 06/12/2018] [Indexed: 12/11/2022] Open
Abstract
Cystic fibrosis (CF) is an autosomal recessive disease caused by CFTR mutations. It is characterized by high NaCl concentration in sweat and the production of a thick and sticky mucus, occluding secretory ducts, intestine and airways, accompanied by chronic inflammation and infections of the lungs. This causes a progressive and lethal decline in lung function. Therefore, finding the mechanisms driving the high susceptibility to lung infections has been a key issue. For decades the prevalent hypothesis was that a reduced airway surface liquid (ASL) volume and composition, and the consequent increased mucus concentration (dehydration), create an environment favoring infections. However, a few years ago, in a pig model of CF, the Na+/K+ concentrations and the ASL volume were found intact. Immediately a different hypothesis arose, postulating a reduced ASL pH as the cause for the increased susceptibility to infections, due to a diminished bicarbonate secretion through CFTR. Noteworthy, a recent report found normal ASL pH values in CF children and in cultured primary airway cells, challenging the ASL pH hypothesis. On the other hand, recent evidences revitalized the hypothesis of a reduced ASL secretion. Thus, the role of the ASL pH in the CF is still a controversial matter. In this review we discuss the basis that sustain the role of CFTR in modulating the extracellular pH, and the recent results sustaining the different points of view. Finding the mechanisms of CFTR signaling that determine the susceptibility to infections is crucial to understand the pathophysiology of CF and related lung diseases.
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Affiliation(s)
- María Macarena Massip-Copiz
- Laboratory of Cellular and Molecular Biology, Institute for Biomedical Research (BIOMED UCA-CONICET), The National Scientific and Technical Research Council (CONICET), and School of Medical Sciences, The Pontifical Catholic University of Argentina (UCA), Buenos Aires, Argentina
| | - Tomás Antonio Santa-Coloma
- Laboratory of Cellular and Molecular Biology, Institute for Biomedical Research (BIOMED UCA-CONICET), The National Scientific and Technical Research Council (CONICET), and School of Medical Sciences, The Pontifical Catholic University of Argentina (UCA), Buenos Aires, Argentina.
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