1
|
Scott M, Lei L, Bierstedt KC, McCray PB, Xie Y. Dynamic measurement of airway surface liquid volume with an ex vivo trachea-chip. LAB ON A CHIP 2024; 24:3093-3100. [PMID: 38779981 PMCID: PMC11165946 DOI: 10.1039/d4lc00134f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024]
Abstract
The volume and composition of airway surface liquid (ASL) is regulated by liquid secretion and absorption across airway epithelia, controlling the pH, solute concentration, and biophysical properties of ASL in health and disease. Here, we developed a method integrating explanted tracheal tissue with a micro-machined device (referred to as "ex vivo trachea-chip") to study the dynamic properties of ASL volume regulation. The ex vivo trachea-chip allows real-time measurement of ASL transport (Jv) with intact airway anatomic structures, environmental control, high-resolution, and enhanced experimental throughput. Applying this technology to freshly excised tissue we observed ASL absorption under basal conditions. The apical application of amiloride, an inhibitor of airway epithelial sodium channels (ENaC), reduced airway liquid absorption. Furthermore, the basolateral addition of NPPB, a Cl- channel inhibitor, reduced the basal rate of ASL absorption, implicating a role for basolateral Cl- channels in ASL volume regulation. When tissues were treated with apical amiloride and basolateral methacholine, a cholinergic agonist that stimulates secretion from airway submucosal glands, the net airway surface liquid production shifted from absorption to secretion. This ex vivo trachea-chip provides a new tool to investigate ASL transport dynamics in pulmonary disease states and may aid the development of new therapies targeting ASL regulation.
Collapse
Affiliation(s)
- Michael Scott
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, USA.
| | - Lei Lei
- Stead Family Department of Pediatrics and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, USA
| | - Kaleb C Bierstedt
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, USA.
| | - Paul B McCray
- Stead Family Department of Pediatrics and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, USA
| | - Yuliang Xie
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, USA.
| |
Collapse
|
2
|
Wu M, Chen JH. CFTR dysfunction leads to defective bacterial eradication on cystic fibrosis airways. Front Physiol 2024; 15:1385661. [PMID: 38699141 PMCID: PMC11063615 DOI: 10.3389/fphys.2024.1385661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 04/04/2024] [Indexed: 05/05/2024] Open
Abstract
Dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel by genetic mutations causes the inherited disease cystic fibrosis (CF). CF lung disease that involves multiple disorders of epithelial function likely results from loss of CFTR function as an anion channel conducting chloride and bicarbonate ions and its function as a cellular regulator modulating the activity of membrane and cytosol proteins. In the absence of CFTR activity, abundant mucus accumulation, bacterial infection and inflammation characterize CF airways, in which inflammation-associated tissue remodeling and damage gradually destroys the lung. Deciphering the link between CFTR dysfunction and bacterial infection in CF airways may reveal the pathogenesis of CF lung disease and guide the development of new treatments. Research efforts towards this goal, including high salt, low volume, airway surface liquid acidosis and abnormal mucus hypotheses are critically reviewed.
Collapse
Affiliation(s)
| | - Jeng-Haur Chen
- College of Life Sciences, Zhejiang Normal University, Jinhua, Zhejiang, China
| |
Collapse
|
3
|
Ramananda Y, Naren AP, Arora K. Functional Consequences of CFTR Interactions in Cystic Fibrosis. Int J Mol Sci 2024; 25:3384. [PMID: 38542363 PMCID: PMC10970640 DOI: 10.3390/ijms25063384] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/09/2024] [Accepted: 03/12/2024] [Indexed: 09/01/2024] Open
Abstract
Cystic fibrosis (CF) is a fatal autosomal recessive disorder caused by the loss of function mutations within a single gene for the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR). CFTR is a chloride channel that regulates ion and fluid transport across various epithelia. The discovery of CFTR as the CF gene and its cloning in 1989, coupled with extensive research that went into the understanding of the underlying biological mechanisms of CF, have led to the development of revolutionary therapies in CF that we see today. The highly effective modulator therapies have increased the survival rates of CF patients and shifted the epidemiological landscape and disease prognosis. However, the differential effect of modulators among CF patients and the presence of non-responders and ineligible patients underscore the need to develop specialized and customized therapies for a significant number of patients. Recent advances in the understanding of the CFTR structure, its expression, and defined cellular compositions will aid in developing more precise therapies. As the lifespan of CF patients continues to increase, it is becoming critical to clinically address the extra-pulmonary manifestations of CF disease to improve the quality of life of the patients. In-depth analysis of the molecular signature of different CF organs at the transcriptional and post-transcriptional levels is rapidly advancing and will help address the etiological causes and variability of CF among patients and develop precision medicine in CF. In this review, we will provide an overview of CF disease, leading to the discovery and characterization of CFTR and the development of CFTR modulators. The later sections of the review will delve into the key findings derived from single-molecule and single-cell-level analyses of CFTR, followed by an exploration of disease-relevant protein complexes of CFTR that may ultimately define the etiological course of CF disease.
Collapse
Affiliation(s)
- Yashaswini Ramananda
- Department of Pediatrics, Division of Pulmonary Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA;
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Anjaparavanda P. Naren
- Department of Pediatrics, Division of Pulmonary Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA;
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Kavisha Arora
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| |
Collapse
|
4
|
Trognon J, Rima M, Lajoie B, Roques C, El Garah F. NaCl-induced modulation of species distribution in a mixed P. aeruginosa / S. aureus / B.cepacia biofilm. Biofilm 2023; 6:100153. [PMID: 37711514 PMCID: PMC10497989 DOI: 10.1016/j.bioflm.2023.100153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 09/16/2023] Open
Abstract
Pseudomonas aeruginosa, Staphylococcus aureus, and Burkholderia cepacia are notorious pathogens known for their ability to form resilient biofilms, particularly within the lung environment of cystic fibrosis (CF) patients. The heightened concentration of NaCl, prevalent in the airway liquid of CF patients' lungs, has been identified as a factor that promotes the growth of osmotolerant bacteria like S. aureus and dampens host antibacterial defenses, thereby fostering favorable conditions for infections. In this study, we aimed to investigate how increased NaCl concentrations impact the development of multi-species biofilms in vitro, using both laboratory strains and clinical isolates of P. aeruginosa, S. aureus, and B. cepacia co-cultures. Employing a low-nutrient culture medium that fosters biofilm growth of the selected species, we quantified biofilm formation through a combination of adherent CFU counts, qPCR analysis, and confocal microscopy observations. Our findings reaffirmed the challenges faced by S. aureus in establishing growth within 1:1 mixed biofilms with P. aeruginosa when cultivated in a minimal medium. Intriguingly, at an elevated NaCl concentration of 145 mM, a symbiotic relationship emerged between S. aureus and P. aeruginosa, enabling their co-existence. Notably, this hyperosmotic environment also exerted an influence on the interplay of these two bacteria with B. cepacia. We demonstrated that elevated NaCl concentrations play a pivotal role in orchestrating the distribution of these three species within the biofilm matrix. Furthermore, our study unveiled the beneficial impact of NaCl on the biofilm growth of clinically relevant mucoid P. aeruginosa strains, as well as two strains of methicillin-sensitive and methicillin-resistant S. aureus. This underscores the crucial role of the microenvironment during the colonization and infection processes. The results suggest that hyperosmotic conditions could hold the key to unlocking a deeper understanding of the genesis and behavior of CF multi-species biofilms.
Collapse
Affiliation(s)
- Jeanne Trognon
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Maya Rima
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Barbora Lajoie
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| | - Christine Roques
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
- CHU Toulouse, Hôpital Purpan, Service de Bactériologie Hygiène, Toulouse, France
| | - Fatima El Garah
- Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INPT, UPS, Toulouse, France
| |
Collapse
|
5
|
Skłodowski K, Suprewicz Ł, Chmielewska-Deptuła SJ, Kaliniak S, Okła S, Zakrzewska M, Minarowski Ł, Mróz R, Daniluk T, Savage PB, Fiedoruk K, Bucki R. Ceragenins exhibit bactericidal properties that are independent of the ionic strength in the environment mimicking cystic fibrosis sputum. Front Microbiol 2023; 14:1290952. [PMID: 38045035 PMCID: PMC10693459 DOI: 10.3389/fmicb.2023.1290952] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 11/02/2023] [Indexed: 12/05/2023] Open
Abstract
The purpose of the work was to investigate the impact of sodium chloride (NaCl) on the antimicrobial efficacy of ceragenins (CSAs) and antimicrobial peptides (AMPs) against bacterial and fungal pathogens associated with cystic fibrosis (CF) lung infections. CF-associated bacterial (Pseudomonas aeruginosa, Ochrobactrum spp., and Staphylococcus aureus), and fungal pathogens (Candida albicans, and Candida tropicalis) were used as target organisms for ceragenins (CSA-13 and CSA-131) and AMPs (LL-37 and omiganan). Susceptibility to the tested compounds was assessed using minimal inhibitory concentrations (MICs) and bactericidal concentrations (MBCs), as well as by colony counting assays in CF sputum samples supplemented with various concentrations of NaCl. Our results demonstrated that ceragenins exhibit potent antimicrobial activity in CF sputum regardless of the NaCl concentration when compared to LL-37 and omiganan. Given the broad-spectrum antimicrobial activity of ceragenins in the microenvironments mimicking the airways of CF patients, ceragenins might be promising agents in managing CF disease.
Collapse
Affiliation(s)
- Karol Skłodowski
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Białystok, Białystok, Poland
| | - Łukasz Suprewicz
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Białystok, Białystok, Poland
| | | | | | - Sławomir Okła
- Holy Cross Cancer Center, Kielce, Poland
- Institute of Health Science, Collegium Medicum, Jan Kochanowski University of Kielce, Kielce, Poland
| | - Magdalena Zakrzewska
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Białystok, Białystok, Poland
| | - Łukasz Minarowski
- 2nd Department of Lung Diseases and Tuberculosis, Medical University of Bialystok, Bialystok, Poland
| | - Robert Mróz
- 2nd Department of Lung Diseases and Tuberculosis, Medical University of Bialystok, Bialystok, Poland
| | - Tamara Daniluk
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Białystok, Białystok, Poland
| | - Paul B. Savage
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - Krzysztof Fiedoruk
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Białystok, Białystok, Poland
| | - Robert Bucki
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Białystok, Białystok, Poland
| |
Collapse
|
6
|
Lei L, Traore S, Romano Ibarra GS, Karp PH, Rehman T, Meyerholz DK, Zabner J, Stoltz DA, Sinn PL, Welsh MJ, McCray PB, Thornell IM. CFTR-rich ionocytes mediate chloride absorption across airway epithelia. J Clin Invest 2023; 133:e171268. [PMID: 37581935 PMCID: PMC10575720 DOI: 10.1172/jci171268] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 08/08/2023] [Indexed: 08/17/2023] Open
Abstract
The volume and composition of a thin layer of liquid covering the airway surface defend the lung from inhaled pathogens and debris. Airway epithelia secrete Cl- into the airway surface liquid through cystic fibrosis transmembrane conductance regulator (CFTR) channels, thereby increasing the volume of airway surface liquid. The discovery that pulmonary ionocytes contain high levels of CFTR led us to predict that ionocytes drive secretion. However, we found the opposite. Elevating ionocyte abundance increased liquid absorption, whereas reducing ionocyte abundance increased secretion. In contrast to other airway epithelial cells, ionocytes contained barttin/Cl- channels in their basolateral membrane. Disrupting barttin/Cl- channel function impaired liquid absorption, and overexpressing barttin/Cl- channels increased absorption. Together, apical CFTR and basolateral barttin/Cl- channels provide an electrically conductive pathway for Cl- flow through ionocytes, and the transepithelial voltage generated by apical Na+ channels drives absorption. These findings indicate that ionocytes mediate liquid absorption, and secretory cells mediate liquid secretion. Segregating these counteracting activities to distinct cell types enables epithelia to precisely control the airway surface. Moreover, the divergent role of CFTR in ionocytes and secretory cells suggests that cystic fibrosis disrupts both liquid secretion and absorption.
Collapse
Affiliation(s)
- Lei Lei
- Stead Family Department of Pediatrics and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine
| | - Soumba Traore
- Stead Family Department of Pediatrics and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine
| | - Guillermo S. Romano Ibarra
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine
| | - Philip H. Karp
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine
- Howard Hughes Medical Institute
| | - Tayyab Rehman
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine
| | - David K. Meyerholz
- Department of Pathology, Roy J. and Lucille A. Carver College of Medicine
| | - Joseph Zabner
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine
| | - David A. Stoltz
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine
- Department of Biomedical Engineering
- Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine
| | - Patrick L. Sinn
- Stead Family Department of Pediatrics and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine
- Department of Microbiology and Immunology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Michael J. Welsh
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine
- Howard Hughes Medical Institute
- Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine
| | - Paul B. McCray
- Stead Family Department of Pediatrics and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine
- Department of Microbiology and Immunology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Ian M. Thornell
- Department of Internal Medicine and Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine
| |
Collapse
|
7
|
Chiavetta RF, Titoli S, Barra V, Cancemi P, Melfi R, Di Leonardo A. Site-Specific RNA Editing of Stop Mutations in the CFTR mRNA of Human Bronchial Cultured Cells. Int J Mol Sci 2023; 24:10940. [PMID: 37446121 DOI: 10.3390/ijms241310940] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/22/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023] Open
Abstract
It is reported that about 10% of cystic fibrosis (CF) patients worldwide have nonsense (stop) mutations in the CFTR gene, which cause the premature termination of CFTR protein synthesis, leading to a truncated and non-functional protein. To address this issue, we investigated the possibility of rescuing the CFTR nonsense mutation (UGA) by sequence-specific RNA editing in CFTR mutant CFF-16HBEge, W1282X, and G542X human bronchial cells. We used two different base editor tools that take advantage of ADAR enzymes (adenosine deaminase acting on RNA) to edit adenosine to inosine (A-to-I) within the mRNA: the REPAIRv2 (RNA Editing for Programmable A to I Replacement, version 2) and the minixABE (A to I Base Editor). Immunofluorescence experiments show that both approaches were able to recover the CFTR protein in the CFTR mutant cells. In addition, RT-qPCR confirmed the rescue of the CFTR full transcript. These findings suggest that site-specific RNA editing may efficiently correct the UGA premature stop codon in the CFTR transcript in CFF-16HBEge, W1282X, and G542X cells. Thus, this approach, which is safer than acting directly on the mutated DNA, opens up new therapeutic possibilities for CF patients with nonsense mutations.
Collapse
Affiliation(s)
- Roberta F Chiavetta
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, 90128 Palermo, Italy
| | - Simona Titoli
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, 90128 Palermo, Italy
| | - Viviana Barra
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, 90128 Palermo, Italy
| | - Patrizia Cancemi
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, 90128 Palermo, Italy
- Centro di Oncobiologia Sperimentale (C.O.B.S.), Viale Delle Scienze, 90128 Palermo, Italy
| | - Raffaella Melfi
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, 90128 Palermo, Italy
| | - Aldo Di Leonardo
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies, University of Palermo, 90128 Palermo, Italy
- Centro di Oncobiologia Sperimentale (C.O.B.S.), Viale Delle Scienze, 90128 Palermo, Italy
| |
Collapse
|
8
|
Pereira R, Barbosa T, Cardoso AL, Sá R, Sousa M. Cystic fibrosis and primary ciliary dyskinesia: Similarities and differences. Respir Med 2023; 209:107169. [PMID: 36828173 DOI: 10.1016/j.rmed.2023.107169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 02/06/2023] [Accepted: 02/18/2023] [Indexed: 02/25/2023]
Abstract
Cystic fibrosis (CF) and Primary ciliary dyskinesia (PCD) are both rare chronic diseases, inherited disorders associated with multiple complications, namely respiratory complications, due to impaired mucociliary clearance that affect severely patients' lives. Although both are classified as rare diseases, PCD has a much lower prevalence than CF, particularly among Caucasians. As a result, CF is well studied, better recognized by clinicians, and with some therapeutic approaches already available. Whereas PCD is still largely unknown, and thus the approach is based on consensus guidelines, expert opinion, and extrapolation from the larger evidence base available for patients with CF. Both diseases have some clinical similarities but are very different, necessitating different treatment by specialists who are familiar with the complexities of each disease.This review aims to provide an overview of the knowledge about the two diseases with a focus on the similarities and differences between both in terms of disease mechanisms, common clinical manifestations, genetics and the most relevant therapeutic options. We hoped to raise clinical awareness about PCD, what it is, how it differs from CF, and how much information is still lacking. Furthermore, this review emphasises the fact that both diseases require ongoing research to find better treatments and, in particular for PCD, to fill the medical and scientific gaps.
Collapse
Affiliation(s)
- Rute Pereira
- Laboratory of Cell Biology, Department of Microscopy, ICBAS-School of Medicine and Biomedical Sciences, University of Porto, Porto, Portugal; UMIB-Unit for Multidisciplinary Research in Biomedicine, ICBAS-UP/ ITR-Laboratory for Integrative and Translational Research in Population Health, UP, Porto, Portugal.
| | - Telma Barbosa
- UMIB-Unit for Multidisciplinary Research in Biomedicine, ICBAS-UP/ ITR-Laboratory for Integrative and Translational Research in Population Health, UP, Porto, Portugal; Department of Pediatrics, Maternal Child Centre of the North (CMIN), University Hospital Centre of Porto (CHUP), Largo da Maternidade, 4050-371, Porto, Portugal.
| | - Ana Lúcia Cardoso
- UMIB-Unit for Multidisciplinary Research in Biomedicine, ICBAS-UP/ ITR-Laboratory for Integrative and Translational Research in Population Health, UP, Porto, Portugal; Department of Pediatrics, Maternal Child Centre of the North (CMIN), University Hospital Centre of Porto (CHUP), Largo da Maternidade, 4050-371, Porto, Portugal.
| | - Rosália Sá
- Laboratory of Cell Biology, Department of Microscopy, ICBAS-School of Medicine and Biomedical Sciences, University of Porto, Porto, Portugal; UMIB-Unit for Multidisciplinary Research in Biomedicine, ICBAS-UP/ ITR-Laboratory for Integrative and Translational Research in Population Health, UP, Porto, Portugal.
| | - Mário Sousa
- Laboratory of Cell Biology, Department of Microscopy, ICBAS-School of Medicine and Biomedical Sciences, University of Porto, Porto, Portugal; UMIB-Unit for Multidisciplinary Research in Biomedicine, ICBAS-UP/ ITR-Laboratory for Integrative and Translational Research in Population Health, UP, Porto, Portugal.
| |
Collapse
|
9
|
Ehre C, Hansson GC, Thornton DJ, Ostedgaard LS. Mucus aberrant properties in CF: Insights from cells and animal models. J Cyst Fibros 2023; 22 Suppl 1:S23-S26. [PMID: 36117114 PMCID: PMC10018425 DOI: 10.1016/j.jcf.2022.08.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/26/2022] [Accepted: 08/30/2022] [Indexed: 10/14/2022]
Abstract
Cystic fibrosis (CF), an autosomal genetic disorder caused by the dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, is characterized by mucus accumulation in the lungs, the intestinal tract, and the pancreatic ducts. Mucins are high-molecular-weight glycoproteins that govern the biochemical and biophysical properties of mucus. In the CF lung, increased mucus viscoelasticity is associated with decreased mucociliary clearance and defects in host defense mechanisms. The link between defective ion channel and abnormal mucus properties has been investigated in studies involving cell and animal models. In this review article, we discuss recent progress toward understanding the different regions and cells that express CFTR in the airways and how mucus is produced and cleared from the lungs. In addition, we reflect on animal models that provided insights into the organization and the role of the mucin network and how mucus and antimicrobial activities act in concert to protect the lungs from invading pathogens.
Collapse
Affiliation(s)
- Camille Ehre
- University of North Carolina at Chapel Hill, Department of Pediatrics, Marsico Lung Institute, Chapel Hill, NC, USA
| | - Gunnar C Hansson
- Department Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - David J Thornton
- The Wellcome Trust Centre for Cell-Matrix Research, and The Lydia Becker Institute of Immunology and Inflammation, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Lynda S Ostedgaard
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
| |
Collapse
|
10
|
Sui H, Xu X, Su Y, Gong Z, Yao M, Liu X, Zhang T, Jiang Z, Bai T, Wang J, Zhang J, Xu C, Luo M. Gene therapy for cystic fibrosis: Challenges and prospects. Front Pharmacol 2022; 13:1015926. [PMID: 36304167 PMCID: PMC9592762 DOI: 10.3389/fphar.2022.1015926] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 09/29/2022] [Indexed: 11/25/2022] Open
Abstract
Cystic fibrosis (CF) is a life-threatening autosomal-recessive disease caused by mutations in a single gene encoding cystic fibrosis transmembrane conductance regulator (CFTR). CF effects multiple organs, and lung disease is the primary cause of mortality. The median age at death from CF is in the early forties. CF was one of the first diseases to be considered for gene therapy, and efforts focused on treating CF lung disease began shortly after the CFTR gene was identified in 1989. However, despite the quickly established proof-of-concept for CFTR gene transfer in vitro and in clinical trials in 1990s, to date, 36 CF gene therapy clinical trials involving ∼600 patients with CF have yet to achieve their desired outcomes. The long journey to pursue gene therapy as a cure for CF encountered more difficulties than originally anticipated, but immense progress has been made in the past decade in the developments of next generation airway transduction viral vectors and CF animal models that reproduced human CF disease phenotypes. In this review, we look back at the history for the lessons learned from previous clinical trials and summarize the recent advances in the research for CF gene therapy, including the emerging CRISPR-based gene editing strategies. We also discuss the airway transduction vectors, large animal CF models, the complexity of CF pathogenesis and heterogeneity of CFTR expression in airway epithelium, which are the major challenges to the implementation of a successful CF gene therapy, and highlight the future opportunities and prospects.
Collapse
Affiliation(s)
- Hongshu Sui
- Department of Histology and Embryology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Science, Jinan, Shandong, China
- *Correspondence: Hongshu Sui, ; Changlong Xu, ; Mingjiu Luo,
| | - Xinghua Xu
- Department of Histology and Embryology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Science, Jinan, Shandong, China
| | - Yanping Su
- Department of Histology and Embryology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Science, Jinan, Shandong, China
| | - Zhaoqing Gong
- Department of Histology and Embryology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Science, Jinan, Shandong, China
| | - Minhua Yao
- Department of Histology and Embryology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Science, Jinan, Shandong, China
| | - Xiaocui Liu
- Department of Histology and Embryology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Science, Jinan, Shandong, China
| | - Ting Zhang
- Department of Histology and Embryology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Science, Jinan, Shandong, China
| | - Ziyao Jiang
- Department of Histology and Embryology, School of Clinical and Basic Medical Sciences, Shandong First Medical University & Shandong Academy of Medical Science, Jinan, Shandong, China
| | - Tianhao Bai
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai’an, China
| | - Junzuo Wang
- The Affiliated Tai’an City Central Hospital of Qingdao University, Tai’an, Shandong, China
| | - Jingjun Zhang
- Department of Neurology, The Second Affiliated Hospital of Shandong First Medical University, Tai’an, Shandong, China
| | - Changlong Xu
- The Reproductive Medical Center of Nanning Second People’s Hospital, Nanning, China
- National Center for International Research of Bio-targeting Theranostics, Guangxi Key Laboratory of Bio-targeting Theranostics, Collaborative Innovation Center for Targeting Tumor Diagnosis and Therapy, Guangxi Talent Highland of Bio-targeting Theranostics, Guangxi Medical University, Nanning, China
- *Correspondence: Hongshu Sui, ; Changlong Xu, ; Mingjiu Luo,
| | - Mingjiu Luo
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai’an, China
- *Correspondence: Hongshu Sui, ; Changlong Xu, ; Mingjiu Luo,
| |
Collapse
|
11
|
Rehman T, Karp PH, Thurman AL, Mather SE, Jain A, Cooney AL, Sinn PL, Pezzulo AA, Duffey ME, Welsh MJ. WNK Inhibition Increases Surface Liquid pH and Host Defense in Cystic Fibrosis Airway Epithelia. Am J Respir Cell Mol Biol 2022; 67:491-502. [PMID: 35849656 PMCID: PMC9564924 DOI: 10.1165/rcmb.2022-0172oc] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/18/2022] [Indexed: 02/05/2023] Open
Abstract
In cystic fibrosis (CF), reduced HCO3- secretion acidifies the airway surface liquid (ASL), and the acidic pH disrupts host defenses. Thus, understanding the control of ASL pH (pHASL) in CF may help identify novel targets and facilitate therapeutic development. In diverse epithelia, the WNK (with-no-lysine [K]) kinases coordinate HCO3- and Cl- transport, but their functions in airway epithelia are poorly understood. Here, we tested the hypothesis that WNK kinases regulate CF pHASL. In primary cultures of differentiated human airway epithelia, inhibiting WNK kinases acutely increased both CF and non-CF pHASL. This response was HCO3- dependent and involved downstream SPAK/OSR1 (Ste20/SPS1-related proline-alanine-rich protein kinase/oxidative stress responsive 1 kinase). Importantly, WNK inhibition enhanced key host defenses otherwise impaired in CF. Human airway epithelia expressed two WNK isoforms in secretory cells and ionocytes, and knockdown of either WNK1 or WNK2 increased CF pHASL. WNK inhibition decreased Cl- secretion and the response to bumetanide, an NKCC1 (sodium-potassium-chloride cotransporter 1) inhibitor. Surprisingly, bumetanide alone or basolateral Cl- substitution also alkalinized CF pHASL. These data suggest that WNK kinases influence the balance between transepithelial Cl- versus HCO3- secretion. Moreover, reducing basolateral Cl- entry may increase HCO3- secretion and raise pHASL, thereby improving CF host defenses.
Collapse
Affiliation(s)
| | - Philip H. Karp
- Department of Internal Medicine and
- Howard Hughes Medical Institute, University of Iowa, Iowa City, Iowa; and
| | | | | | | | | | | | | | - Michael E. Duffey
- Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York
| | - Michael J. Welsh
- Department of Internal Medicine and
- Department of Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, and
- Howard Hughes Medical Institute, University of Iowa, Iowa City, Iowa; and
| |
Collapse
|
12
|
Yan Z, Vorhies K, Feng Z, Park SY, Choi SH, Zhang Y, Winter M, Sun X, Engelhardt JF. Recombinant Adeno-Associated Virus-Mediated Editing of the G551D Cystic Fibrosis Transmembrane Conductance Regulator Mutation in Ferret Airway Basal Cells. Hum Gene Ther 2022; 33:1023-1036. [PMID: 35686451 PMCID: PMC9595624 DOI: 10.1089/hum.2022.036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 05/03/2022] [Indexed: 12/30/2022] Open
Abstract
Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis (CF), a chronic disease that affects multiple organs, including the lung. We developed a CF ferret model of a scarless G551→D substitution in CFTR (CFTRG551D-KI), enabling approaches to correct this gating mutation in CF airways via gene editing. Homology-directed repair (HDR) was tested in Cas9-expressing CF airway basal cells (Cas9-GKI) from this model, as well as reporter basal cells (Y66S-Cas9-GKI) that express an integrated nonfluorescent Y66S-EGFP (enhanced green fluorescent protein) mutant gene to facilitate rapid assessment of HDR by the restoration of fluorescence. Recombinant adeno-associated virus (rAAV) vectors were used to deliver two DNA templates and sgRNAs for dual-gene editing at the EGFP and CFTR genes, followed by fluorescence-activated cell sorting of EGFPY66S-corrected cells. When gene-edited airway basal cells were polarized at an air-liquid interface, unsorted and EGFPY66S-corrected sorted populations gave rise to 26.0% and 70.4% CFTR-mediated Cl- transport of that observed in non-CF cultures, respectively. The consequences of gene editing at the CFTRG551D locus by HDR and nonhomologous end joining (NHEJ) were assessed by targeted gene next-generation sequencing (NGS) against a specific amplicon. NGS revealed HDR corrections of 3.1% of G551 sequences in the unsorted population of rAAV-infected cells, and 18.4% in the EGFPY66S-corrected cells. However, the largest proportion of sequences had indels surrounding the CRISPR (clustered regularly interspaced short palindromic repeats) cut site, demonstrating that NHEJ was the dominant repair pathway. This approach to simultaneously coedit at two genomic loci using rAAV may have utility as a model system for optimizing gene-editing efficiencies in proliferating airway basal cells through the modulation of DNA repair pathways in favor of HDR.
Collapse
Affiliation(s)
- Ziying Yan
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Kai Vorhies
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Zehua Feng
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Soo Yeun Park
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Soon H. Choi
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Yulong Zhang
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Michael Winter
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Xingshen Sun
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - John F. Engelhardt
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| |
Collapse
|
13
|
Lin Q, Pilewski JM, Di YP. Acidic Microenvironment Determines Antibiotic Susceptibility and Biofilm Formation of Pseudomonas aeruginosa. Front Microbiol 2021; 12:747834. [PMID: 34867864 PMCID: PMC8640179 DOI: 10.3389/fmicb.2021.747834] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/20/2021] [Indexed: 01/02/2023] Open
Abstract
Pseudomonas aeruginosa is the most prevalent bacterial species that contribute to cystic fibrosis (CF) respiratory failure. The impaired function of CF transmembrane conductance regulator leads to abnormal epithelial Cl-/HCO3 - transport and acidification of airway surface liquid. However, it remains unclear why the CF lung is most commonly infected by Pseudomonas aeruginosa versus other pathogens. We carried out studies to investigate if lower pH helps Pseudomonas aeruginosa adapt and thrive in the CF-like acidic lung environment. Our results revealed that Pseudomonas aeruginosa generally forms more biofilm, induces antibiotic resistance faster in acidic conditions, and can be reversed by returning the acidic environment to physiologically neutral conditions. Pseudomonas aeruginosa appears to be highly adaptive to the CF-like acidic pH environment. By studying the effects of an acidic environment on bacterial response, we may provide a new therapeutic option in preventing chronic Pseudomonas aeruginosa infection and colonization.
Collapse
Affiliation(s)
- Qiao Lin
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, United States
| | - Joseph M Pilewski
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Y Peter Di
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA, United States
| |
Collapse
|
14
|
Van den Bossche S, De Broe E, Coenye T, Van Braeckel E, Crabbé A. The cystic fibrosis lung microenvironment alters antibiotic activity: causes and effects. Eur Respir Rev 2021; 30:30/161/210055. [PMID: 34526313 DOI: 10.1183/16000617.0055-2021] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 04/23/2021] [Indexed: 01/08/2023] Open
Abstract
Chronic airway colonisation by Pseudomonas aeruginosa, a hallmark of cystic fibrosis (CF) lung disease, is associated with increased morbidity and mortality and despite aggressive antibiotic treatment, P. aeruginosa is able to persist in CF airways. In vitro antibiotic susceptibility assays are poor predictors of antibiotic efficacy to treat respiratory tract infections in the CF patient population and the selection of the antibiotic(s) is often made on an empirical base. In the current review, we discuss the factors that are responsible for the discrepancies between antibiotic activity in vitro and clinical efficacy in vivo We describe how the CF lung microenvironment, shaped by host factors (such as iron, mucus, immune mediators and oxygen availability) and the microbiota, influences antibiotic activity and varies widely between patients. A better understanding of the CF microenvironment and population diversity may thus help improve in vitro antibiotic susceptibility testing and clinical decision making, in turn increasing the success rate of antibiotic treatment.
Collapse
Affiliation(s)
| | - Emma De Broe
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| | - Eva Van Braeckel
- Dept of Respiratory Medicine, Cystic Fibrosis Reference Centre, Ghent University Hospital, Ghent, Belgium.,Dept of Internal Medicine and Paediatrics, Ghent University, Ghent, Belgium
| | - Aurélie Crabbé
- Laboratory of Pharmaceutical Microbiology, Ghent University, Ghent, Belgium
| |
Collapse
|
15
|
Harris A. Human molecular genetics and the long road to treating cystic fibrosis. Hum Mol Genet 2021; 30:R264-R273. [PMID: 34245257 DOI: 10.1093/hmg/ddab191] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/04/2021] [Accepted: 07/06/2021] [Indexed: 11/13/2022] Open
Abstract
The causative gene in cystic fibrosis was identified in 1989, three years before the publication of the first issue of Human Molecular Genetics. CFTR was among the first genes underlying a common inherited disorder to be cloned, and hence its subsequent utilization towards a cure for CF provides a roadmap for other monogenic diseases. Over the past 30 years the advances that built upon knowledge of the gene and the CFTR protein to develop effective therapeutics have been remarkable, and yet the setbacks have also been challenging. Technological progress in other fields has often circumvented the barriers. This review focuses on key aspects of CF diagnostics and current approaches to develop new therapies for all CFTR mutations. It also highlights the major research advances that underpinned progress towards treatments, and considers the remaining obstacles.
Collapse
Affiliation(s)
- Ann Harris
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| |
Collapse
|
16
|
Drzymała-Czyż S, Krzyżanowska-Jankowska P, Dziedzic K, Lisowska A, Kurek S, Goździk-Spychalska J, Kononets V, Woźniak D, Mądry E, Walkowiak J. Severe Genotype, Pancreatic Insufficiency and Low Dose of Pancreatic Enzymes Associate with Abnormal Serum Sterol Profile in Cystic Fibrosis. Biomolecules 2021; 11:313. [PMID: 33669566 PMCID: PMC7922133 DOI: 10.3390/biom11020313] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/13/2021] [Accepted: 02/16/2021] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Several factors could lead to lipid disturbances observed in cystic fibrosis (CF). This study aimed to assess sterol homeostasis in CF and define potential exogenous and endogenous determinants of lipid dysregulation. METHODS The study involved 55 CF patients and 45 healthy subjects (HS). Sterol concentrations (μg/dL) were measured by gas chromatography/mass spectrometry. CF was characterised by lung function, pancreatic status, liver disease and diabetes coexistence, Pseudomonas aeruginosa colonisation and BMI. CFTR genotypes were classified as severe or other. RESULTS Campesterol and β-sitosterol concentrations were lower (p = 0.0028 and p < 0.0001, respectively) and lathosterol levels (reflecting endogenous cholesterol biosynthesis) were higher (p = 0.0016) in CF patients than in HS. Campesterol and β-sitosterol concentrations were lower in patients with a severe CFTR genotype, pancreatic insufficiency and lower pancreatic enzyme dose (lipase units/gram of fat). In multiple regression analyses, β-sitosterol and campesterol concentrations were predicted by genotype and pancreatic insufficiency, whereas cholesterol and its fractions were predicted by phytosterol concentrations, age, dose of pancreatic enzymes, nutritional status and genotype. CONCLUSIONS Independent determinants of lipid status suggest that malabsorption and pancreatic enzyme supplementation play a significant role in sterol abnormalities. The measurement of campesterol and β-sitosterol concentrations in CF patients may serve for the assessment of the effectiveness of pancreatic enzyme replacement therapy and/or compliance, but further research is required.
Collapse
Affiliation(s)
- Sławomira Drzymała-Czyż
- Department of Pediatric Gastroenterology and Metabolic Diseases, Poznan University of Medical Sciences, 60-572 Poznań, Poland; (P.K.-J.); (K.D.); (A.L.); (S.K.); (J.W.)
- Department of Bromatology, Poznan University of Medical Sciences, 60-354 Poznań, Poland;
| | - Patrycja Krzyżanowska-Jankowska
- Department of Pediatric Gastroenterology and Metabolic Diseases, Poznan University of Medical Sciences, 60-572 Poznań, Poland; (P.K.-J.); (K.D.); (A.L.); (S.K.); (J.W.)
| | - Krzysztof Dziedzic
- Department of Pediatric Gastroenterology and Metabolic Diseases, Poznan University of Medical Sciences, 60-572 Poznań, Poland; (P.K.-J.); (K.D.); (A.L.); (S.K.); (J.W.)
- Department of Food Science and Nutrition, Institute of Food Technology of Plant Origin, Poznań University of Life Sciences, 60-637 Poznań, Poland
| | - Aleksandra Lisowska
- Department of Pediatric Gastroenterology and Metabolic Diseases, Poznan University of Medical Sciences, 60-572 Poznań, Poland; (P.K.-J.); (K.D.); (A.L.); (S.K.); (J.W.)
| | - Szymon Kurek
- Department of Pediatric Gastroenterology and Metabolic Diseases, Poznan University of Medical Sciences, 60-572 Poznań, Poland; (P.K.-J.); (K.D.); (A.L.); (S.K.); (J.W.)
| | - Joanna Goździk-Spychalska
- Department of Pulmonology, Allergology and Respiratory Oncology, Poznan University of Medical Sciences, 60-569 Poznań, Poland;
| | - Victoria Kononets
- Department of Natural Sciences Disciplines, West Kazakhstan Marat Ospanov Medical University, Aktobe 030012, Kazakhstan;
| | - Dagmara Woźniak
- Department of Bromatology, Poznan University of Medical Sciences, 60-354 Poznań, Poland;
| | - Edyta Mądry
- Department of Physiology, Poznan University of Medical Sciences, 61-781 Poznań, Poland;
| | - Jarosław Walkowiak
- Department of Pediatric Gastroenterology and Metabolic Diseases, Poznan University of Medical Sciences, 60-572 Poznań, Poland; (P.K.-J.); (K.D.); (A.L.); (S.K.); (J.W.)
| |
Collapse
|
17
|
Rasmussen LW, Stanford D, Patel K, Raju SV. Evaluation of secondhand smoke effects on CFTR function in vivo. Respir Res 2020; 21:70. [PMID: 32192506 PMCID: PMC7082971 DOI: 10.1186/s12931-020-1324-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 02/17/2020] [Indexed: 01/01/2023] Open
Affiliation(s)
- Lawrence W Rasmussen
- Departments of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
- Environmental Health Sciences, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Denise Stanford
- Departments of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
- Gregory Fleming James Cystic Fibrosis Research Center, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Krina Patel
- Departments of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - S Vamsee Raju
- Departments of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA.
- Gregory Fleming James Cystic Fibrosis Research Center, The University of Alabama at Birmingham, Birmingham, AL, USA.
- Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, USA.
| |
Collapse
|
18
|
Singh S, Hornick D, Fedler J, Launspach JL, Teresi ME, Santacroce TR, Cavanaugh JE, Horan R, Nelson G, Starner TD, Zabner J, Durairaj L. Randomized controlled study of aerosolized hypertonic xylitol versus hypertonic saline in hospitalized patients with pulmonary exacerbation of cystic fibrosis. J Cyst Fibros 2019; 19:108-113. [PMID: 31327670 DOI: 10.1016/j.jcf.2019.06.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 06/13/2019] [Accepted: 06/30/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND Cystic fibrosis (CF) lung disease is characterized by chronic bacterial infection and recurrent pulmonary exacerbations. Xylitol is a 5-carbon sugar that can lower the airway surface salt concentration and augment innate immunity. We examined the safety and efficacy of aerosolized xylitol use for 2 weeks in subjects hospitalized with a pulmonary exacerbation of CF. METHODS In a 2-week study, 60 subjects with cystic fibrosis and FEV1 > 30% predicted were enrolled to receive aerosolized 7% hypertonic saline (4 ml) or 15% xylitol (5 ml) twice a day for 14 days. Outcomes assessed included change from baseline in FEV1% predicted, change in sputum microbial density, revised CF quality of life questionnaire including the respiratory symptom score, time to next hospitalization for a pulmonary exacerbation, and frequency of adverse events. RESULTS 59 subjects completed the study (one subject in the saline group withdrew before any study product administration). No significant differences were noted between the 2 arms in mean changes in lung function, sputum microbial density for Pseudomonas aeruginosa and Staphylococcus aureus, body weight, quality of life, and frequency of adverse events. CONCLUSIONS Aerosolized hypertonic xylitol was well-tolerated among subjects hospitalized for CF pulmonary exacerbation. Future studies examining efficacy for long term use in patients with CF lung disease would be worthwhile. The clinical trial registration number for this study is NCT00928135.
Collapse
Affiliation(s)
- Sachinkumar Singh
- Stead Family Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Douglas Hornick
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Janel Fedler
- Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
| | - Janice L Launspach
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Mary E Teresi
- Stead Family Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | | | - Joseph E Cavanaugh
- Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
| | - Rebecca Horan
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - George Nelson
- Doris Duke Clinical Research Scholar, University of Iowa, USA
| | - Timothy D Starner
- Department of Pediatrics, University of Wisconsin-Madison, 600 Highland Ave, Madison, WI 53792, USA
| | - Joseph Zabner
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Lakshmi Durairaj
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
| |
Collapse
|
19
|
Kunzelmann K, Ousingsawat J, Cabrita I, Doušová T, Bähr A, Janda M, Schreiber R, Benedetto R. TMEM16A in Cystic Fibrosis: Activating or Inhibiting? Front Pharmacol 2019; 10:3. [PMID: 30761000 PMCID: PMC6362895 DOI: 10.3389/fphar.2019.00003] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 01/04/2019] [Indexed: 12/26/2022] Open
Abstract
The inflammatory airway disease cystic fibrosis (CF) is characterized by airway obstruction due to mucus hypersecretion, airway plugging, and bronchoconstriction. The cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel is dysfunctional in CF, leading to defects in epithelial transport. Although CF pathogenesis is still disputed, activation of alternative Cl- channels is assumed to improve lung function in CF. Two suitable non-CFTR Cl- channels are present in the airway epithelium, the Ca2+ activated channel TMEM16A and SLC26A9. Activation of these channels is thought to be feasible to improve hydration of the airway mucus and to increase mucociliary clearance. Interestingly, both channels are upregulated during inflammatory lung disease. They are assumed to support fluid secretion, necessary to hydrate excess mucus and to maintain mucus clearance. During inflammation, however, TMEM16A is upregulated particularly in mucus producing cells, with only little expression in ciliated cells. Recently it was shown that knockout of TMEM16A in ciliated cells strongly compromises Cl- conductance and attenuated mucus secretion, but does not lead to a CF-like lung disease and airway plugging. Along this line, activation of TMEM16A by denufosol, a stable purinergic ligand, failed to demonstrate any benefit to CF patients in earlier studies. It rather induced adverse effects such as cough. A number of studies suggest that TMEM16A is essential for mucus secretion and possibly also for mucus production. Evidence is now provided for a crucial role of TMEM16A in fusion of mucus-filled granules with the apical plasma membrane and cellular exocytosis. This is probably due to local Ca2+ signals facilitated by TMEM16A. Taken together, TMEM16A supports fluid secretion by ciliated airway epithelial cells, but also maintains excessive mucus secretion during inflammatory airway disease. Because TMEM16A also supports airway smooth muscle contraction, inhibition rather than activation of TMEM16A might be the appropriate treatment for CF lung disease, asthma and COPD. As a number of FDA-approved and well-tolerated drugs have been shown to inhibit TMEM16A, evaluation in clinical trials appears timely.
Collapse
Affiliation(s)
- Karl Kunzelmann
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
| | | | - Inês Cabrita
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
| | - Tereza Doušová
- Department of Pediatrics, Second Faculty of Medicine, University Hospital Motol, Charles University in Prague, Prague, Czechia
| | - Andrea Bähr
- Institute of Molecular Animal Breeding and Biotechnology, Ludwig-Maximilians-Universität München, Munich, Germany
- Innere Medizin I, Klinikum Rechts der Isar der TU München, München, Germany
| | - Melanie Janda
- Institute of Molecular Animal Breeding and Biotechnology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Rainer Schreiber
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
| | - Roberta Benedetto
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
| |
Collapse
|
20
|
Awatade NT, Wong SL, Hewson CK, Fawcett LK, Kicic A, Jaffe A, Waters SA. Human Primary Epithelial Cell Models: Promising Tools in the Era of Cystic Fibrosis Personalized Medicine. Front Pharmacol 2018; 9:1429. [PMID: 30581387 PMCID: PMC6293199 DOI: 10.3389/fphar.2018.01429] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 11/19/2018] [Indexed: 12/29/2022] Open
Abstract
Cystic fibrosis (CF) is an inherited disorder where individual disease etiology and response to therapeutic intervention is impacted by CF transmembrane regulator (CFTR) mutations and other genetic modifiers. CFTR regulates multiple mechanisms in a diverse range of epithelial tissues. In this Review, we consolidate the latest updates in the development of primary epithelial cellular model systems relevant for CF. We discuss conventional two-dimensional (2-D) airway epithelial cell cultures, the backbone of in vitro cellular models to date, as well as improved expansion protocols to overcome finite supply of the cellular source. We highlight a range of strategies for establishment of three dimensional (3-D) airway and intestinal organoid models and evaluate the limitations and potential improvements in each system, focusing on their application in CF. The in vitro CFTR functional assays in patient-derived organoids allow for preclinical pharmacotherapy screening to identify responsive patients. It is likely that organoids will be an invaluable preclinical tool to unravel disease mechanisms, design novel treatments, and enable clinicians to provide personalized management for patients with CF.
Collapse
Affiliation(s)
- Nikhil T. Awatade
- Faculty of Medicine, School of Women's and Children's Health, University of New South Wales, Sydney, NSW, Australia
- Molecular and Integrative Cystic Fibrosis Research Centre (miCF_RC), School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Sharon L. Wong
- Faculty of Medicine, School of Women's and Children's Health, University of New South Wales, Sydney, NSW, Australia
- Molecular and Integrative Cystic Fibrosis Research Centre (miCF_RC), School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Chris K. Hewson
- Faculty of Medicine, School of Women's and Children's Health, University of New South Wales, Sydney, NSW, Australia
- Molecular and Integrative Cystic Fibrosis Research Centre (miCF_RC), School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Laura K. Fawcett
- Faculty of Medicine, School of Women's and Children's Health, University of New South Wales, Sydney, NSW, Australia
- Molecular and Integrative Cystic Fibrosis Research Centre (miCF_RC), School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
- Department of Respiratory Medicine, Sydney Children's Hospital, Sydney, NSW, Australia
| | - Anthony Kicic
- Centre for Child Health Research, Telethon Kids Institute, The University of Western Australia, Nedlands, WA, Australia
- Occupation and Environment, School of Public Health, Curtin University, Bentley, WA, Australia
- Faculty of Health and Medical Sciences, The University of Western Australia, Nedlands, WA, Australia
- Department of Respiratory and Sleep Medicine, Perth Children's Hospital, Nedlands, WA, Australia
- Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, The University of Western Australia, Nedlands, WA, Australia
| | - Adam Jaffe
- Faculty of Medicine, School of Women's and Children's Health, University of New South Wales, Sydney, NSW, Australia
- Molecular and Integrative Cystic Fibrosis Research Centre (miCF_RC), School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
- Department of Respiratory Medicine, Sydney Children's Hospital, Sydney, NSW, Australia
| | - Shafagh A. Waters
- Faculty of Medicine, School of Women's and Children's Health, University of New South Wales, Sydney, NSW, Australia
- Molecular and Integrative Cystic Fibrosis Research Centre (miCF_RC), School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| |
Collapse
|
21
|
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.
Collapse
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.
| |
Collapse
|
22
|
Graham SM, Scott SN, Launspach J, Zabner J. The Effects of Fluticasone Propionate on Nasal Epithelial Potential Difference. ACTA ACUST UNITED AC 2018. [DOI: 10.1177/194589240201600304] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Human airway epithelium maintains homeostasis of the fluid and salt composition at the airway surface by a regulated transport of sodium and chloride ions. The volume and composition of airway surface liquid have been shown to be important in the pathogenesis of cystic fibrosis, nasal inflammatory disease, and nasal polyposis. The presence of functional epithelial sodium and chloride channels in the airway epithelium can be evaluated electrically by measuring the voltage across the nasal epithelium (Vt). Because fluticasone propionate is commonly used to treat nasal inflammatory diseases, we tested its effect on the nasal ion transport. Methods A single-blind prospective trial was performed on 12 healthy volunteers. Subjects were randomized to receive either fluticasone propionate or normal saline nasal spray twice daily for 2 weeks. We measured the nasal voltage at baseline, days 3 and 14, and 2 weeks after cessation of treatment. The basal voltage, the change in voltage after perfusion with amiloride (sodium channel blocker), and the change in voltage after perfusion with isoproterenol in a low-chloride buffer (chloride channel activator) were recorded. Saccharin clearance times were measured also. Results Two-week treatment with fluticasone propionate resulted in a significant increase in the change in Vt after perfusion with amiloride. There was no significant change in the group treated with normal saline. These findings also were observed on day 3 and were reversed completely after the 2-week washout period. The increase in amiloride-sensitive Vt did not result in a decrease in mucociliary clearance. Conclusions This study suggests that one effect of fluticasone propionate use on nasal mucosa in normal volunteers is increased epithelial sodium absorption.
Collapse
Affiliation(s)
- Scott M. Graham
- Departments of Otolaryngology-Head and Neck Surgery and University of Iowa, Iowa City, Iowa
| | - Shaun N. Scott
- Departments of Otolaryngology-Head and Neck Surgery and University of Iowa, Iowa City, Iowa
| | - Janice Launspach
- Departments of Internal Medicine, University of Iowa, Iowa City, Iowa
| | - Joseph Zabner
- Departments of Internal Medicine, University of Iowa, Iowa City, Iowa
| |
Collapse
|
23
|
Collawn JF, Bartoszewski R, Lazrak A, Matalon S. Therapeutic attenuation of the epithelial sodium channel with a SPLUNC1-derived peptide in airway diseases. Am J Physiol Lung Cell Mol Physiol 2018; 314:L239-L242. [PMID: 29351436 DOI: 10.1152/ajplung.00516.2017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- James F Collawn
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham , Birmingham, Alabama.,Pulmonary Injury and Repair Center, University of Alabama at Birmingham , Birmingham, Alabama.,Cystic Fibrosis Research Center, University of Alabama at Birmingham , Birmingham, Alabama
| | - Rafal Bartoszewski
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk , Gdansk , Poland
| | | | - Sadis Matalon
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham , Birmingham, Alabama.,Pulmonary Injury and Repair Center, University of Alabama at Birmingham , Birmingham, Alabama.,Cystic Fibrosis Research Center, University of Alabama at Birmingham , Birmingham, Alabama.,Department of Anesthesiology, University of Alabama at Birmingham , Birmingham, Alabama
| |
Collapse
|
24
|
Abdula D, Lerud R, Rananavare S. Bubbling and foaming assisted clearing of mucin plugs in microfluidic Y-junctions. J Biomech 2017; 64:1-7. [PMID: 27156594 DOI: 10.1016/j.jbiomech.2016.04.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 04/19/2016] [Accepted: 04/24/2016] [Indexed: 10/21/2022]
Abstract
Microfluidic Y-junctions were used to study mechanical mechanisms involved in pig gastric mucin (PGM) plug removal from within one of two bifurcation branches with 2-phase air and liquid flow. Water control experiments showed moderate plug removal due to shear from vortex formation in the blockage branch and suggest a PGM yield stress of 35Pa, as determined by computational fluid dynamics. Addition of hexadecyltrimethylammonium bromide (CTAB) surfactant improved clearing effectiveness due to bubbling in 1mm diameter channels and foaming in 500μm diameter channels. Plug removal mechanisms have been identified as vortex shear, bubble scouring, and then foam scouring as air flow rate is increased with constant liquid flow. The onset of bubbling and foaming is attributed to a flow regime transition from slug to slug-annular. Flow rates explored for 1mm channels are typically experienced by bronchioles in generations 8 and 9 of lungs. Results have implications on treatment of cystic fibrosis and other lung diseases.
Collapse
Affiliation(s)
- Daner Abdula
- Department of Biomedical Engineering, Oregon Health and Science University, Portland, OR 97239, United States.
| | - Ryan Lerud
- Department of Chemistry, Portland State University, Portland, OR 97201, United States
| | - Shankar Rananavare
- Department of Chemistry, Portland State University, Portland, OR 97201, United States
| |
Collapse
|
25
|
Grandjean Lapierre S, Phelippeau M, Hakimi C, Didier Q, Reynaud-Gaubert M, Dubus JC, Drancourt M. Cystic fibrosis respiratory tract salt concentration: An Exploratory Cohort Study. Medicine (Baltimore) 2017; 96:e8423. [PMID: 29381919 PMCID: PMC5708918 DOI: 10.1097/md.0000000000008423] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
In cystic fibrosis patients, electrolytic and osmolality imbalance secondary to cystic fibrosis transmembrane conductance regulator mutations may impact on mucoid secretion accumulation and secondary colonization by opportunistic pathogens such as nontuberculous mycobacteria.We performed a noninvasive exploratory prospective controlled clinical study comparing sputum salinity and acid-base characteristics of cystic fibrosis and noncystic fibrosis control patients. A total of 57 patients and 62 controls were included.Sputum salt concentrations were 10.5 g/L (95% CI: 7.7-13.3) in patients and 7.4 g/L (95% CI: 5.9-8.9) in aged-matched controls, a difference that was found to be statistically significant (P < .05). No difference in pH was observed between patients and controls.These differences in respiratory secretions salt concentrations could influence host-pathogen interactions in the context of cystic fibrosis respiratory infections. We propose to include respiratory secretion salt measurement as a routine analysis on cystic fibrosis patients' sputum submitted for bacterial culture.
Collapse
Affiliation(s)
| | | | - Cyrine Hakimi
- Aix-Marseille Université, URMITE Méditerranée Infection
| | | | - Martine Reynaud-Gaubert
- Center de Resource et de Compétences de la Mucoviscidose adulte; équipe de Transplantation pulmonaire, CHU Hôpital Nord, URMITE Aix-Marseille Université
| | - Jean-Christophe Dubus
- Center de Resource et de Compétences de la Mucoviscidose pédiatrique CHU Hôpital la Timone, Marseille, France
| | | |
Collapse
|
26
|
Bicarbonate in cystic fibrosis. J Cyst Fibros 2017; 16:653-662. [PMID: 28732801 DOI: 10.1016/j.jcf.2017.06.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 06/22/2017] [Accepted: 06/22/2017] [Indexed: 11/20/2022]
Abstract
BACKGROUND Cystic fibrosis (CF, mucoviscidosis) is caused by mutations in the gene encoding CF transmembrane conductance regulator (CFTR), which is a chloride and bicarbonate channel necessary for fluid secretion and extracellular alkalization. For a long time, research concentrated on abnormal Cl- and Na+ transport, but neglected bicarbonate as a crucial factor in CF. METHODS The present short review reports early findings as well as recent insights into the role of CFTR for bicarbonate transport and its defects in CF. RESULTS The available data indicate impaired bicarbonate transport not only in pancreas, intestine, airways, and reproductive organs, but also in salivary glands, sweat duct and renal tubular epithelial cells. Defective bicarbonate transport is closely related to the impaired mucus properties and mucus blocking in secretory organs of CF patients, causing the life threatening lung disease. CONCLUSIONS Apart from the devastating lung disease, abrogated bicarbonate transport also leads to many other organ dysfunctions, which are outlined in the present review.
Collapse
|
27
|
Schmidt H, Michel C, Braubach P, Fauler M, Neubauer D, Thompson KE, Frick M, Mizaikoff B, Dietl P, Wittekindt OH. Water Permeability Adjusts Resorption in Lung Epithelia to Increased Apical Surface Liquid Volumes. Am J Respir Cell Mol Biol 2017; 56:372-382. [DOI: 10.1165/rcmb.2016-0161oc] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Hanna Schmidt
- Institute of General Physiology, Ulm University, Ulm, Germany
| | | | - Peter Braubach
- Institute of Pathology, Medizinische Hochschule Hannover, Hannover, Germany
| | - Michael Fauler
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Daniel Neubauer
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany; and
| | - Kristin E. Thompson
- Institute of General Physiology, Ulm University, Ulm, Germany
- Institute de la Santé et de la Recherche Médicale, UMR_S938, Sorbonne Universités, Paris, France
| | - Manfred Frick
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Boris Mizaikoff
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany; and
| | - Paul Dietl
- Institute of General Physiology, Ulm University, Ulm, Germany
| | | |
Collapse
|
28
|
Concepcion AR, Feske S. Regulation of epithelial ion transport in exocrine glands by store-operated Ca 2+ entry. Cell Calcium 2016; 63:53-59. [PMID: 28027799 DOI: 10.1016/j.ceca.2016.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 12/17/2016] [Indexed: 02/08/2023]
Abstract
Store-operated Ca2+ entry (SOCE) is a conserved mechanism of Ca2+ influx that regulates Ca2+ signaling in many cell types. SOCE is activated by depletion of endoplasmic reticulum (ER) Ca2+ stores in response to physiological agonist stimulation. After it was first postulated by J.W. Putney Jr. in 1986, SOCE has been described in a large number of non-excitable cell types including secretory cells of different exocrine glands. Here we discuss the mechanisms by which SOCE controls salt and fluid secretion in exocrine glands, with a special focus on eccrine sweat glands. In sweat glands, SOCE plays an important, non-redundant role in regulating the function of Ca2+-activated Cl- channels (CaCC), Cl- secretion and sweat production. In the absence of key regulators of SOCE such as the CRAC channel pore subunit ORAI1 and its activator STIM1, the Ca2+-activated chloride channel TMEM16A is inactive and fails to secrete Cl-, resulting in anhidrosis in mice and human patients.
Collapse
Affiliation(s)
- Axel R Concepcion
- Department of Pathology, New York University School of Medicine, New York, NY, 10016, USA
| | - Stefan Feske
- Department of Pathology, New York University School of Medicine, New York, NY, 10016, USA.
| |
Collapse
|
29
|
Abou Alaiwa MH, Launspach JL, Sheets KA, Rivera JA, Gansemer ND, Taft PJ, Thorne PS, Welsh MJ, Stoltz DA, Zabner J. Repurposing tromethamine as inhaled therapy to treat CF airway disease. JCI Insight 2016; 1:87535. [PMID: 27390778 DOI: 10.1172/jci.insight.87535] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In cystic fibrosis (CF), loss of CF transmembrane conductance regulator (CFTR) anion channel activity causes airway surface liquid (ASL) pH to become acidic, which impairs airway host defenses. One potential therapeutic approach is to correct the acidic pH in CF airways by aerosolizing HCO3- and/or nonbicarbonate pH buffers. Here, we show that raising ASL pH with inhaled HCO3- increased pH. However, the effect was transient, and pH returned to baseline values within 30 minutes. Tromethamine (Tham) is a buffer with a long serum half-life used as an i.v. formulation to treat metabolic acidosis. We found that Tham aerosols increased ASL pH in vivo for at least 2 hours and enhanced bacterial killing. Inhaled hypertonic saline (7% NaCl) is delivered to people with CF in an attempt to promote mucus clearance. Because an increased ionic strength inhibits ASL antimicrobial factors, we added Tham to hypertonic saline and applied it to CF sputum. We found that Tham alone and in combination with hypertonic saline increased pH and enhanced bacterial killing. These findings suggest that aerosolizing the HCO3--independent buffer Tham, either alone or in combination with hypertonic saline, might be of therapeutic benefit in CF airway disease.
Collapse
Affiliation(s)
| | - Janice L Launspach
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine
| | - Kelsey A Sheets
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine
| | - Jade A Rivera
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine
| | - Nicholas D Gansemer
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine
| | - Peter J Taft
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine
| | - Peter S Thorne
- Department of Occupational and Environmental Health, College of Public Health
| | - Michael J Welsh
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine.,Department of Molecular Physiology and Biophysics.,Howard Hughes Medical Institute.,Pappajohn Biomedical Institute, and
| | - David A Stoltz
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine.,Department of Molecular Physiology and Biophysics.,Pappajohn Biomedical Institute, and.,Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, USA
| | - Joseph Zabner
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine.,Pappajohn Biomedical Institute, and
| |
Collapse
|
30
|
Larrouy-Maumus G, Marino LB, Madduri AVR, Ragan TJ, Hunt DM, Bassano L, Gutierrez MG, Moody DB, Pavan FR, de Carvalho LPS. Cell-Envelope Remodeling as a Determinant of Phenotypic Antibacterial Tolerance in Mycobacterium tuberculosis. ACS Infect Dis 2016; 2:352-360. [PMID: 27231718 PMCID: PMC4877114 DOI: 10.1021/acsinfecdis.5b00148] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Indexed: 12/03/2022]
Abstract
![]()
The mechanisms that lead to phenotypic
antibacterial tolerance in bacteria remain poorly understood. We investigate
whether changes in NaCl concentration toward physiologically higher
values affect antibacterial efficacy against Mycobacterium
tuberculosis (Mtb), the causal agent of human tuberculosis.
Indeed, multiclass phenotypic antibacterial tolerance is observed
during Mtb growth in physiologic saline. This includes changes in
sensitivity to ethionamide, ethambutol, d-cycloserine, several
aminoglycosides, and quinolones. By employing organism-wide metabolomic
and lipidomic approaches combined with phenotypic tests, we identified
a time-dependent biphasic adaptive response after exposure of Mtb
to physiological levels of NaCl. A first rapid, extensive, and reversible
phase was associated with changes in core and amino acid metabolism.
In a second phase, Mtb responded with a substantial remodelling of
plasma membrane and outer lipid membrane composition. We demonstrate
that phenotypic tolerance at physiological concentrations of NaCl
is the result of changes in plasma and outer membrane lipid remodeling
and not changes in core metabolism. Altogether, these results indicate
that physiologic saline-induced antibacterial tolerance is kinetically
coupled to cell envelope changes and demonstrate that metabolic changes
and growth arrest are not the cause of phenotypic tolerance observed
in Mtb exposed to physiologic concentrations of NaCl. Importantly,
this work uncovers a role for bacterial cell envelope remodeling in
antibacterial tolerance, alongside well-documented allterations in
respiration, metabolism, and growth rate.
Collapse
Affiliation(s)
- Gérald Larrouy-Maumus
- Laboratory
of Chemical Biology of Tuberculosis Pathogenesis, MRC Centre for Molecular
Bacteriology and Infection, Imperial College London, Kensington, London SW7 2DD, United Kingdom
| | - Leonardo B. Marino
- School of Pharmaceutical
Sciences, São Paulo State University (UNESP), 4801-902 Araraquara, SP, Brazil
| | - Ashoka V. R. Madduri
- Division of Rheumatology, Immunology and Allergy, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts 02115, United States
| | | | | | - Lucrezia Bassano
- Laboratory
of Chemical Biology of Tuberculosis Pathogenesis, MRC Centre for Molecular
Bacteriology and Infection, Imperial College London, Kensington, London SW7 2DD, United Kingdom
| | | | - D. Branch Moody
- Division of Rheumatology, Immunology and Allergy, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Fernando R. Pavan
- School of Pharmaceutical
Sciences, São Paulo State University (UNESP), 4801-902 Araraquara, SP, Brazil
| | | |
Collapse
|
31
|
Differential In Vitro and In Vivo Toxicities of Antimicrobial Peptide Prodrugs for Potential Use in Cystic Fibrosis. Antimicrob Agents Chemother 2016; 60:2813-21. [PMID: 26902766 DOI: 10.1128/aac.00157-16] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 02/16/2016] [Indexed: 02/07/2023] Open
Abstract
There has been considerable interest in the use of antimicrobial peptides (AMPs) as antimicrobial agents for the treatment of many conditions, including cystic fibrosis (CF). The challenging conditions of the CF patient lung require robust AMPs that are active in an environment of high proteolytic activity but that also have low cytotoxicity and immunogenicity. Previously, we developed prodrugs of AMPs that limited the cytotoxic effects of AMP treatment by rendering the antimicrobial activity dependent on the host enzyme neutrophil elastase (NE). However, cytotoxicity remained an issue. Here, we describe the further optimization of the AMP prodrug (pro-AMP) model for CF to produce pro-WMR, a peptide with greatly reduced cytotoxicity (50% inhibitory concentration against CFBE41o- cells, >300 μM) compared to that of the previous group of pro-AMPs. The bactericidal activity of pro-WMR was increased in NE-rich bronchoalveolar lavage (BAL) fluid from CF patients (range, 8.4% ± 6.9% alone to 91.5% ± 5.8% with BAL fluid; P = 0.0004), an activity differential greater than that of previous pro-AMPs. In a murine model of lung delivery, the pro-AMP modification reduced host toxicity, with pro-WMR being less toxic than the active peptide. Previously, host toxicity issues have hampered the clinical application of AMPs. However, the development of application-specific AMPs with modifications that minimize toxicity similar to those described here can significantly advance their potential use in patients. The combination of this prodrug strategy with a highly active AMP has the potential to produce new therapeutics for the challenging conditions of the CF patient lung.
Collapse
|
32
|
Pradenas GA, Ross BN, Torres AG. Burkholderia cepacia Complex Vaccines: Where Do We Go from here? Vaccines (Basel) 2016; 4:vaccines4020010. [PMID: 27092530 PMCID: PMC4931627 DOI: 10.3390/vaccines4020010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 04/07/2016] [Accepted: 04/08/2016] [Indexed: 01/15/2023] Open
Abstract
Burkholderia comprises a wide variety of environmental Gram-negative bacteria. Burkholderia cepacia complex (Bcc) includes several Burkholderia species that pose a health hazard as they are able to cause respiratory infections in patients with chronic granulomatous disease and cystic fibrosis. Due to the intrinsic resistance to a wide array of antibiotics and naturally occurring immune evasion strategies, treatment of Bcc infections often proves to be unsuccessful. To date, limited work related to vaccine development has been performed for Bcc pathogens. In this review, we have gathered key aspects of Bcc research that have been reported in recent years related to vaccine efforts, virulence, immune responses, and animal models, and use this information to inform the research community of areas of opportunity toward development of a viable Bcc vaccine.
Collapse
Affiliation(s)
- Gonzalo A Pradenas
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - Brittany N Ross
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - Alfredo G Torres
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA.
- Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX 77555, USA.
| |
Collapse
|
33
|
Matalon S, Bartoszewski R, Collawn JF. Role of epithelial sodium channels in the regulation of lung fluid homeostasis. Am J Physiol Lung Cell Mol Physiol 2015; 309:L1229-38. [PMID: 26432872 DOI: 10.1152/ajplung.00319.2015] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 09/25/2015] [Indexed: 01/11/2023] Open
Abstract
In utero, fetal lung epithelial cells actively secrete Cl(-) ions into the lung air spaces while Na(+) ions follow passively to maintain electroneutrality. This process, driven by an electrochemical gradient generated by the Na(+)-K(+)-ATPase, is responsible for the secretion of fetal fluid that is essential for normal lung development. Shortly before birth, a significant upregulation of amiloride-sensitive epithelial channels (ENaCs) on the apical side of the lung epithelial cells results in upregulation of active Na(+) transport. This process is critical for the reabsorption of fetal lung fluid and the establishment of optimum gas exchange. In the adult lung, active Na(+) reabsorption across distal lung epithelial cells limits the degree of alveolar edema in patients with acute lung injury and cardiogenic edema. Cl(-) ions are transported either paracellularly or transcellularly to preserve electroneutrality. An increase in Cl(-) secretion across the distal lung epithelium has been reported following an acute increase in left atrial pressure and may result in pulmonary edema. In contrast, airway epithelial cells secrete Cl(-) through apical cystic fibrosis transmembrane conductance regulator and Ca(2+)-activated Cl(-) channels and absorb Na(+). Thus the coordinated action of Cl(-) secretion and Na(+) absorption is essential for maintenance of the volume of epithelial lining fluid that, in turn, maximizes mucociliary clearance and facilitates clearance of bacteria and debris from the lungs. Any factor that interferes with Na(+) or Cl(-) transport or dramatically upregulates ENaC activity in airway epithelial cells has been associated with lung diseases such as cystic fibrosis or chronic obstructive lung disease. In this review we focus on the role of the ENaC, the mechanisms involved in ENaC regulation, and how ENaC dysregulation can lead to lung pathology.
Collapse
Affiliation(s)
- Sadis Matalon
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Department of Cell, Developmental, and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Pulmonary Injury and Repair Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Gregory Fleming James Cystic Fibrosis Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - Rafal Bartoszewski
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Gdansk, Poland
| | - James F Collawn
- Department of Cell, Developmental, and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Pulmonary Injury and Repair Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Gregory Fleming James Cystic Fibrosis Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
| |
Collapse
|
34
|
Abstract
Our studies demonstrate that sodium chloride (NaCl) induces changes in biofilm, mediated by increased production of polysaccharides intercellular adhesion (PIA). We identified 12 proteins that showed higher abundance in increased level of NaCl. This includes one important protein (IsaA) known to be associated with biofilm stability. In addition, we also found higher abundance of a cold shock protein, CspA, at higher NaCl. We have also identified several other proteins that are differentially expressed to the elevated levels of NaCl and mapped them in the regulatory pathways of PIA. The majority of proteins are involved with various aspects bacterial metabolic function. Our results demonstrated that NaCl influences gene regulatory networks controlling exopolysaccharide expression.
Collapse
Affiliation(s)
- Nazrul Islam
- Department of Chemical and Biochemical Engineering, University of Maryland Baltimore County (UMBC), 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Julia M Ross
- Department of Chemical and Biochemical Engineering, University of Maryland Baltimore County (UMBC), 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Mark R Marten
- Department of Chemical and Biochemical Engineering, University of Maryland Baltimore County (UMBC), 1000 Hilltop Circle, Baltimore, MD 21250, USA
| |
Collapse
|
35
|
Azizi F, Arredouani A, Mohammad RM. Airway surface liquid volume expansion induces rapid changes in amiloride-sensitive Na+ transport across upper airway epithelium-Implications concerning the resolution of pulmonary edema. Physiol Rep 2015; 3:3/9/e12453. [PMID: 26333829 PMCID: PMC4600371 DOI: 10.14814/phy2.12453] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
During airway inflammation, airway surface liquid volume (ASLV) expansion may result from the movement of plasma proteins and excess liquid into the airway lumen due to extravasation and elevation of subepithelial hydrostatic pressure. We previously demonstrated that elevation of submucosal hydrostatic pressure increases airway epithelium permeability resulting in ASLV expansion by 500 μL cm−2 h−1. Liquid reabsorption by healthy airway epithelium is regulated by active Na+ transport at a rate of 5 μL cm−2 h−1. Thus, during inflammation the airway epithelium may be submerged by a large volume of luminal liquid. Here, we have investigated the mechanism by which ASLV expansion alters active epithelial Na+ transport, and we have characterized the time course of the change. We used primary cultures of tracheal airway epithelium maintained under air interface (basal ASLV, depth is 7 ± 0.5 μm). To mimic airway flooding, ASLV was expanded to a depth of 5 mm. On switching from basal to expanded ASLV conditions, short-circuit current (Isc, a measure of total transepithelial active ion transport) declined by 90% with a half-time (t1/2) of 1 h. 24 h after the switch, there was no significant change in ATP concentration nor in the number of functional sodium pumps as revealed by [3H]-ouabain binding. However, amiloride-sensitive uptake of 22Na+ was reduced by 70% upon ASLV expansion. This process is reversible since after returning cells back to air interface, Isc recovered with a t1/2 of 5–10 h. These results may have important clinical implications concerning the development of Na+ channels activators and resolution of pulmonary edema.
Collapse
Affiliation(s)
- Fouad Azizi
- Interim Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar
| | | | - Ramzi M Mohammad
- Interim Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar
| |
Collapse
|
36
|
Melo E, Kasper JY, Unger RE, Farré R, Kirkpatrick CJ. Development of a Bronchial Wall Model: Triple Culture on a Decellularized Porcine Trachea. Tissue Eng Part C Methods 2015; 21:909-21. [DOI: 10.1089/ten.tec.2014.0543] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Esther Melo
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Respiratorias, Bunyola, Spain
- Institut Investigacions Biomediques August Pi Sunyer, Barcelona, Spain
| | - Jennifer Y. Kasper
- Institute of Pathology, University Medical Center, Johannes-Guttenberg-University Mainz, Mainz, Germany
| | - Ronald E. Unger
- Institute of Pathology, University Medical Center, Johannes-Guttenberg-University Mainz, Mainz, Germany
| | - Ramon Farré
- Unitat de Biofísica i Bioenginyeria, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Respiratorias, Bunyola, Spain
- Institut Investigacions Biomediques August Pi Sunyer, Barcelona, Spain
| | - Charles James Kirkpatrick
- Institute of Pathology, University Medical Center, Johannes-Guttenberg-University Mainz, Mainz, Germany
| |
Collapse
|
37
|
Sharp K, Crampin E, Sneyd J. A spatial model of fluid recycling in the airways of the lung. J Theor Biol 2015; 382:198-215. [PMID: 26169010 DOI: 10.1016/j.jtbi.2015.06.050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 06/26/2015] [Accepted: 06/30/2015] [Indexed: 12/11/2022]
Abstract
The genetic disease cystic fibrosis (CF) is a mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, and results in viscous mucus and impaired mucociliary clearance leading to chronic recurring pulmonary infections. Although extensive experimental research has been conducted over the last few decades, CF lung pathophysiology remains controversial. There are two competing explanations for the observed depletion of periciliary liquid (PCL) in CF lungs. The low volume hypothesis assumes fluid hyperabsorption through surface epithelia due to an over-active epithelial Na(+) channel (ENaC), and the low secretion hypothesis assumes inspissated mucins secreted from glands due to lack of serous fluid secreted from gland acini. We present a spatial mathematical model that reflects in vivo fluid recycling via submucosal gland (SMG) secretion, and absorption through surface epithelia. We then test the model in CF conditions by increasing ENaC open probability and decreasing SMG flux while simultaneously reducing CFTR open probability. Increasing ENaC activity only results in increased fluid absorption across surface epithelia, as seen in in vitro experiments. However, combining potential CF mechanisms results in markedly less fluid absorbed while providing the largest reduction in PCL volume, suggesting that a compromise in gland fluid secretion dominates over increased ENaC activity to decrease the amount of fluid transported transcellularly in CF lungs in vivo. Model results also indicate that a spatial model is necessary for an accurate calculation of total fluid transport, as the effects of spatial gradients can be severe, particularly in close proximity to the SMGs.
Collapse
Affiliation(s)
- Katie Sharp
- Department of Mathematics, University of Auckland, 23 Princes St, Auckland CBD, Auckland 1010, New Zealand.
| | - Edmund Crampin
- Department of Biomedical Engineering, Level 4, University of Melbourne, Parkville 3010, Victoria, Australia
| | - James Sneyd
- Department of Mathematics, University of Auckland, 23 Princes St, Auckland CBD, Auckland 1010, New Zealand
| |
Collapse
|
38
|
Dong Q, Ernst SE, Ostedgaard LS, Shah VS, Ver Heul AR, Welsh MJ, Randak CO. Mutating the Conserved Q-loop Glutamine 1291 Selectively Disrupts Adenylate Kinase-dependent Channel Gating of the ATP-binding Cassette (ABC) Adenylate Kinase Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) and Reduces Channel Function in Primary Human Airway Epithelia. J Biol Chem 2015; 290:14140-53. [PMID: 25887396 PMCID: PMC4447984 DOI: 10.1074/jbc.m114.611616] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Indexed: 11/06/2022] Open
Abstract
The ATP-binding cassette (ABC) transporter cystic fibrosis transmembrane conductance regulator (CFTR) and two other non-membrane-bound ABC proteins, Rad50 and a structural maintenance of chromosome (SMC) protein, exhibit adenylate kinase activity in the presence of physiologic concentrations of ATP and AMP or ADP (ATP + AMP ⇆ 2 ADP). The crystal structure of the nucleotide-binding domain of an SMC protein in complex with the adenylate kinase bisubstrate inhibitor P(1),P(5)-di(adenosine-5') pentaphosphate (Ap5A) suggests that AMP binds to the conserved Q-loop glutamine during the adenylate kinase reaction. Therefore, we hypothesized that mutating the corresponding residue in CFTR, Gln-1291, selectively disrupts adenylate kinase-dependent channel gating at physiologic nucleotide concentrations. We found that substituting Gln-1291 with bulky side-chain amino acids abolished the effects of Ap5A, AMP, and adenosine 5'-monophosphoramidate on CFTR channel function. 8-Azidoadenosine 5'-monophosphate photolabeling of the AMP-binding site and adenylate kinase activity were disrupted in Q1291F CFTR. The Gln-1291 mutations did not alter the potency of ATP at stimulating current or ATP-dependent gating when ATP was the only nucleotide present. However, when physiologic concentrations of ADP and AMP were added, adenylate kinase-deficient Q1291F channels opened significantly less than wild type. Consistent with this result, we found that Q1291F CFTR displayed significantly reduced Cl(-) channel function in well differentiated primary human airway epithelia. These results indicate that a highly conserved residue of an ABC transporter plays an important role in adenylate kinase-dependent CFTR gating. Furthermore, the results suggest that adenylate kinase activity is important for normal CFTR channel function in airway epithelia.
Collapse
Affiliation(s)
- Qian Dong
- From the Stead Family Department of Pediatrics
| | - Sarah E Ernst
- the Department of Internal Medicine, the Howard Hughes Medical Institute, Iowa City, Iowa 52242
| | | | - Viral S Shah
- the Department of Molecular Physiology and Biophysics, and the Medical Scientist Training Program, University of Iowa, Iowa City, Iowa 52242 and
| | | | - Michael J Welsh
- the Department of Internal Medicine, the Howard Hughes Medical Institute, Iowa City, Iowa 52242 the Department of Molecular Physiology and Biophysics, and
| | | |
Collapse
|
39
|
H-Ras mediates the inhibitory effect of epidermal growth factor on the epithelial Na+ channel. PLoS One 2015; 10:e0116938. [PMID: 25774517 PMCID: PMC4361710 DOI: 10.1371/journal.pone.0116938] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 12/01/2014] [Indexed: 11/21/2022] Open
Abstract
The present study investigates the role of small G-proteins of the Ras family in the epidermal growth factor (EGF)-activated cellular signalling pathway that downregulates activity of the epithelial Na+ channel (ENaC). We found that H-Ras is a key component of this EGF-activated cellular signalling mechanism in M1 mouse collecting duct cells. Expression of a constitutively active H-Ras mutant inhibited the amiloride-sensitive current. The H-Ras-mediated signalling pathway that inhibits activity of ENaC involves c-Raf, and that the inhibitory effect of H-Ras on ENaC is abolished by the MEK1/2 inhibitor, PD98059. The inhibitory effect of H-Ras is not mediated by Nedd4-2, a ubiquitin protein ligase that regulates the abundance of ENaC at the cell surface membrane, or by a negative effect of H-Ras on proteolytic activation of the channel. The inhibitory effects of EGF and H-Ras on ENaC, however, were not observed in cells in which expression of caveolin-1 (Cav-1) had been knocked down by siRNA. These findings suggest that the inhibitory effect of EGF on ENaC-dependent Na+ absorption is mediated via the H-Ras/c-Raf, MEK/ERK signalling pathway, and that Cav-1 is an essential component of this EGF-activated signalling mechanism. Taken together with reports that mice expressing a constitutive mutant of H-Ras develop renal cysts, our findings suggest that H-Ras may play a key role in the regulation of renal ion transport and renal development.
Collapse
|
40
|
Lavallée-Adam M, Rauniyar N, McClatchy DB, Yates JR. PSEA-Quant: a protein set enrichment analysis on label-free and label-based protein quantification data. J Proteome Res 2014; 13:5496-509. [PMID: 25177766 PMCID: PMC4258137 DOI: 10.1021/pr500473n] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The majority of large-scale proteomics quantification methods yield long lists of quantified proteins that are often difficult to interpret and poorly reproduced. Computational approaches are required to analyze such intricate quantitative proteomics data sets. We propose a statistical approach to computationally identify protein sets (e.g., Gene Ontology (GO) terms) that are significantly enriched with abundant proteins with reproducible quantification measurements across a set of replicates. To this end, we developed PSEA-Quant, a protein set enrichment analysis algorithm for label-free and label-based protein quantification data sets. It offers an alternative approach to classic GO analyses, models protein annotation biases, and allows the analysis of samples originating from a single condition, unlike analogous approaches such as GSEA and PSEA. We demonstrate that PSEA-Quant produces results complementary to GO analyses. We also show that PSEA-Quant provides valuable information about the biological processes involved in cystic fibrosis using label-free protein quantification of a cell line expressing a CFTR mutant. Finally, PSEA-Quant highlights the differences in the mechanisms taking place in the human, rat, and mouse brain frontal cortices based on tandem mass tag quantification. Our approach, which is available online, will thus improve the analysis of proteomics quantification data sets by providing meaningful biological insights.
Collapse
Affiliation(s)
- Mathieu Lavallée-Adam
- Department of Chemical Physiology, The Scripps Research Institute , 10550 N. Torrey Pines Rd., La Jolla, California 92037, United States
| | | | | | | |
Collapse
|
41
|
Yoon SS, Hassett DJ. Chronic Pseudomonas aeruginosa infection in cystic fibrosis airway disease: metabolic changes that unravel novel drug targets. Expert Rev Anti Infect Ther 2014; 2:611-23. [PMID: 15482224 DOI: 10.1586/14787210.2.4.611] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The cystic fibrosis (CF) airways have an incompletely characterized defect in innate defense that eventually leads to bacterial infection and airway inflammation. Persistent Pseudomonas aerugionsa infection resulting from defective innate immunity and a bacterial phenotypic switch to a more intractable mucoid form inside the airway are now well established as important components of CF pathogenesis. Broad-based factors leading to chronic infection will be discussed with respect to: bacterial virulence in the context of biofilm formation, quorum sensing machinery and alginate overproduction, and failure of innate lung immunity in CF airways. In addition, a controversial question as to whether inflammation or infection comes first during CF airway disease will be addressed. Finally, a new hypothesis, that P. aeruginosa thrives as biofilms within the thickened anaerobic mucus layers, will be developed.
Collapse
Affiliation(s)
- Sang Sun Yoon
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, OH 45267-0524, USA.
| | | |
Collapse
|
42
|
Reddy MM, Stutts MJ. Status of fluid and electrolyte absorption in cystic fibrosis. Cold Spring Harb Perspect Med 2013; 3:a009555. [PMID: 23284077 DOI: 10.1101/cshperspect.a009555] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Salt and fluid absorption is a shared function of many of the body's epithelia, but its use is highly adapted to the varied physiological roles of epithelia-lined organs. These functions vary from control of hydration of outward-facing epithelial surfaces to conservation and regulation of total body volume. In the most general context, salt and fluid absorption is driven by active Na(+) absorption. Cl(-) is absorbed passively through various available paths in response to the electrical driving force that results from active Na(+) absorption. Absorption of salt creates a concentration gradient that causes water to be absorbed passively, provided the epithelium is water permeable. Key differences notwithstanding, the transport elements used for salt and fluid absorption are broadly similar in diverse epithelia, but the regulation of these elements enables salt absorption to be tailored to very different physiological needs. Here we focus on salt absorption by exocrine glands and airway epithelia. In cystic fibrosis, salt and fluid absorption by gland duct epithelia is effectively prevented by the loss of cystic fibrosis transmembrane conductance regulator (CFTR). In airway epithelia, salt and fluid absorption persists, in the absence of CFTR-mediated Cl(-) secretion. The contrast of these tissue-specific changes in CF tissues is illustrative of how salt and fluid absorption is differentially regulated to accomplish tissue-specific physiological objectives.
Collapse
Affiliation(s)
- M M Reddy
- Department of Pediatrics, UCSD School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | | |
Collapse
|
43
|
Liao Z, Dong J, Hu X, Wang T, Wan C, Li X, Li L, Guo L, Xu D, Wen F. Enhanced expression of human β-defensin 2 in peripheral lungs of patients with chronic obstructive pulmonary disease. Peptides 2012; 38:350-6. [PMID: 23000304 DOI: 10.1016/j.peptides.2012.09.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2012] [Revised: 09/12/2012] [Accepted: 09/12/2012] [Indexed: 02/05/2023]
Abstract
Human β-defensin 2 (hBD-2) has antimicrobial activity and may play a role in airway mucosal defense, but studies have not yet examined its expression in lung tissue of patients with chronic obstructive pulmonary disease (COPD). Here we investigated hBD-2 levels in lung tissues of COPD patients and analyzed their correlations with IL-8, IL-1β, cigarette smoking and lung function in order to see whether the protein may be involved in pathogenesis of the disease. Peripheral lung tissue specimens were obtained from 51 patients who underwent lung resection for peripheral lung cancer: healthy non-smokers (n=8), healthy current smokers (n=7), non-smokers with COPD (n=11), and current smokers with COPD (n=25). RT-PCR and immunohistochemical staining were used to detect expression levels of hBD-2, IL-8 and IL-1β. Expression of hBD-2 mRNA was significantly higher in COPD patients than in healthy controls, and significantly higher in current smokers than in non-smokers (p<0.05). Among healthy controls, hBD-2 mRNA levels were similar between current smokers and non-smokers. Immunohistochemistry showed hBD-2 protein to be expressed mainly in epithelia of distal bronchioles and its expression pattern among our patient groups mirrored that of the mRNA. IL-8 mRNA levels were significantly higher in COPD patients than in healthy controls (p<0.05), while IL-1β mRNA levels did not differ significantly among the groups. Levels of hBD-2 mRNA positively correlated with levels of IL-8 mRNA (r=0.545, p=0.002), and negatively correlated with FEV1/FVC ratios and with predicted FEV1% values (r=-0.406, p=0.011). Our results indicate that hBD-2 expression is elevated in distal airways of COPD patients and that it may be involved in pathogenesis of the disease. Our data implicate cigarette smoking as a factor that may elevate hBD-2 levels in lung tissues of COPD patients.
Collapse
Affiliation(s)
- Zenglin Liao
- Division of Pulmonary Diseases, State Key Laboratory of Biotherapy of China, and Department of Respiratory Medicine, West China Hospital of Sichuan University, Chengdu, Sichuan 610041, China.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
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.
Collapse
Affiliation(s)
- Silvia M Kreda
- Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina, Chapel Hill, NC 27517-7248, USA
| | | | | |
Collapse
|
45
|
Roomans GM. Pharmacological Approaches to Correcting the Ion Transport Defect in Cystic Fibrosis. ACTA ACUST UNITED AC 2012; 2:413-31. [PMID: 14719993 DOI: 10.1007/bf03256668] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Cystic fibrosis (CF) is a lethal genetic disease caused by a mutation in a membrane protein, the cystic fibrosis transmembrane conductance regulator (CFTR), which mainly (but not exclusively) functions as a chloride channel. The main clinical symptoms are chronic obstructive lung disease, which is responsible for most of the morbidity and mortality associated with CF, and pancreatic insufficiency. About 1000 mutations of the gene coding for CFTR are currently known; the most common of these, present in the great majority of the patients (Delta508) results in the deletion of a phenylalanine at position 508. In this mutation, the aberrant CFTR is not transported to the membrane but degraded in the ubiquitin-proteasome pathway. The aim of this review is to give an overview of the pharmacologic strategies currently used in attempts to overcome the ion transport defect in CF. One strategy to develop pharmacologic treatment for CF is to inhibit the breakdown of DeltaF508-CFTR by interfering with the chaperones involved in the folding of CFTR. At least in in vitro systems, this can be accomplished by sodium phenylbutyrate, or S-nitrosoglutathione (GSNO), and also by genistein or benzo[c]quinolizinium compounds. It is also possible to stimulate CFTR or its mutated forms, when present in the plasma membrane, using xanthines, genistein, and various other compounds, such as benzamidizoles and benzoxazoles, benzo[c]quinolizinium compounds or phenantrolines. Experimental results are not always unambiguous, and adverse effects have been incompletely tested. Some clinical tests have been done on sodium phenyl butyrate, GSNO and genistein, mostly in respect to other diseases, and the results demonstrate that these drugs are reasonably well tolerated. Their efficiency in the treatment of CF has not yet been demonstrated, however. An alternative strategy is to compensate for the defective chloride transport by CFTR by stimulation of other chloride channels. This can be done via purinergic receptors. A phase I study using a stable uridine triphosphate analog has recently been completed. A second alternative strategy is to attempt to maintain hydration of the airway mucus by inhibiting Na(+) uptake by the epithelial Na(+) channel using amiloride or stable analogs of amiloride. Clinical tests so far have been inconclusive. A number of other suggestions are currently being explored. The minority of patients with CF who have a stop mutation may benefit from treatment with gentamicin. The difficulties in finding a pharmacologic treatment for CF may be due to the fact that CFTR has additional functions besides chloride transport, and interfering with CFTR biosynthesis or activation implies interference with central cellular processes, which may have undesirable adverse effects.
Collapse
Affiliation(s)
- Godfried M Roomans
- Department of Medical Cell Biology, University of Uppsala, Uppsala, Sweden.
| |
Collapse
|
46
|
Pezzulo AA, Tang XX, Hoegger MJ, Abou Alaiwa MH, Ramachandran S, Moninger TO, Karp PH, Wohlford-Lenane CL, Haagsman HP, van Eijk M, Bánfi B, Horswill AR, Stoltz DA, McCray PB, Welsh MJ, Zabner J. Reduced airway surface pH impairs bacterial killing in the porcine cystic fibrosis lung. Nature 2012; 487:109-13. [PMID: 22763554 PMCID: PMC3390761 DOI: 10.1038/nature11130] [Citation(s) in RCA: 593] [Impact Index Per Article: 49.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 04/05/2012] [Indexed: 12/18/2022]
Abstract
Cystic fibrosis (CF) is a life-shortening disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene 1. Although bacterial lung infection and the resulting inflammation cause most of the morbidity and mortality, how loss of CFTR first disrupts airway host defense has remained uncertain 2–6. We asked what abnormalities impair eradication when a bacterium lands on the pristine surface of a newborn CF airway? To investigate these defects, we interrogated the viability of individual bacteria immobilized on solid grids and placed on the airway surface. As a model we studied CF pigs, which spontaneously develop hallmark features of CF lung disease 7,8. At birth, their lungs lack infection and inflammation, but have a reduced ability to eradicate bacteria 8. Here we show that in newborn wild-type pigs, the thin layer of airway surface liquid (ASL) rapidly killed bacteria in vivo, when removed from the lung, and in primary epithelial cultures. Lack of CFTR reduced bacterial killing. We found that ASL pH was more acidic in CF, and reducing pH inhibited the antimicrobial activity of ASL. Reducing ASL pH diminished bacterial killing in wild-type pigs, and increasing ASL pH rescued killing in CF pigs. These results directly link the initial host defense defect to loss of CFTR, an anion channel that facilitates HCO3− transport 9–13. Without CFTR, airway epithelial HCO3− secretion is defective, ASL pH falls and inhibits antimicrobial function, and thereby impairs killing of bacteria that enter the newborn lung. These findings suggest that increasing ASL pH might prevent the initial infection in patients with CF and that assaying bacterial killing could report on the benefit of therapeutic interventions.
Collapse
Affiliation(s)
- Alejandro A Pezzulo
- Department of Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
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.
Collapse
Affiliation(s)
- James F Collawn
- Department of Cell, Developmental and Integrative Biology, School of Medicine, University of Alabama at Birmingham, 35294-0005, USA.
| | | | | | | |
Collapse
|
48
|
Itani OA, Chen JH, Karp PH, Ernst S, Keshavjee S, Parekh K, Klesney-Tait J, Zabner J, Welsh MJ. Human cystic fibrosis airway epithelia have reduced Cl- conductance but not increased Na+ conductance. Proc Natl Acad Sci U S A 2011; 108:10260-10265. [PMID: 21646513 PMCID: PMC3121869 DOI: 10.1073/pnas.1106695108] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Loss of cystic fibrosis transmembrane conductance regulator (CFTR) anion channel function causes cystic fibrosis (CF) lung disease. CFTR is expressed in airway epithelia, but how CF alters electrolyte transport across airway epithelia has remained uncertain. Recent studies of a porcine model showed that in vivo, excised, and cultured CFTR(-/-) and CFTR(ΔF508/ΔF508) airway epithelia lacked anion conductance, and they did not hyperabsorb Na(+). Therefore, we asked whether Cl(-) and Na(+) conductances were altered in human CF airway epithelia. We studied differentiated primary cultures of tracheal/bronchial epithelia and found that transepithelial conductance (Gt) under basal conditions and the cAMP-stimulated increase in Gt were markedly attenuated in CF epithelia compared with non-CF epithelia. These data reflect loss of the CFTR anion conductance. In CF and non-CF epithelia, the Na(+) channel inhibitor amiloride produced similar reductions in Gt and Na(+) absorption, indicating that Na(+) conductance in CF epithelia did not exceed that in non-CF epithelia. Consistent with previous reports, adding amiloride caused greater reductions in transepithelial voltage and short-circuit current in CF epithelia than in non-CF epithelia; these changes are attributed to loss of a Cl(-) conductance. These results indicate that Na(+) conductance was not increased in these cultured CF tracheal/bronchial epithelia and point to loss of anion transport as key to airway epithelial dysfunction in CF.
Collapse
Affiliation(s)
| | - Jeng-Haur Chen
- Departments of Internal Medicine
- The Howard Hughes Medical Institute, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242; and
| | - Philip H. Karp
- Departments of Internal Medicine
- The Howard Hughes Medical Institute, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242; and
| | | | - Shaf Keshavjee
- Toronto Lung Transplant Program,University of Toronto, Toronto, ON, Canada M5G 2C4
| | | | | | | | - Michael J. Welsh
- Departments of Internal Medicine
- Molecular Physiology and Biophysics and
- The Howard Hughes Medical Institute, The Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242; and
| |
Collapse
|
49
|
Chen JH, Stoltz DA, Karp PH, Ernst SE, Pezzulo AA, Moninger TO, Rector MV, Reznikov LR, Launspach JL, Chaloner K, Zabner J, Welsh MJ. Loss of anion transport without increased sodium absorption characterizes newborn porcine cystic fibrosis airway epithelia. Cell 2011; 143:911-23. [PMID: 21145458 DOI: 10.1016/j.cell.2010.11.029] [Citation(s) in RCA: 181] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Revised: 08/31/2010] [Accepted: 11/02/2010] [Indexed: 10/18/2022]
Abstract
Defective transepithelial electrolyte transport is thought to initiate cystic fibrosis (CF) lung disease. Yet, how loss of CFTR affects electrolyte transport remains uncertain. CFTR⁻(/)⁻ pigs spontaneously develop lung disease resembling human CF. At birth, their airways exhibit a bacterial host defense defect, but are not inflamed. Therefore, we studied ion transport in newborn nasal and tracheal/bronchial epithelia in tissues, cultures, and in vivo. CFTR⁻(/)⁻ epithelia showed markedly reduced Cl⁻ and HCO₃⁻ transport. However, in contrast to a widely held view, lack of CFTR did not increase transepithelial Na(+) or liquid absorption or reduce periciliary liquid depth. Like human CF, CFTR⁻(/)⁻ pigs showed increased amiloride-sensitive voltage and current, but lack of apical Cl⁻ conductance caused the change, not increased Na(+) transport. These results indicate that CFTR provides the predominant transcellular pathway for Cl⁻ and HCO₃⁻ in porcine airway epithelia, and reduced anion permeability may initiate CF airway disease.
Collapse
Affiliation(s)
- Jeng-Haur Chen
- Department of Internal Medicine, University of Iowa, Iowa City, 52242, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Chen EYT, Yang N, Quinton PM, Chin WC. A new role for bicarbonate in mucus formation. Am J Physiol Lung Cell Mol Physiol 2010; 299:L542-9. [PMID: 20693315 DOI: 10.1152/ajplung.00180.2010] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The impact of small anions on the physical properties of gel-forming mucin has been almost overlooked relative to that of cations. Recently, based on the coincident abnormalities in HCO(3)(-) secretion and abnormal mucus formed in the hereditary disease cystic fibrosis (CF), HCO(3)(-) was hypothesized to be critical in the formation of normal mucus by virtue of its ability to sequester Ca(2+) from condensed mucins being discharged from cells. However, direct evidence of the impact of HCO(3)(-) on mucus properties is lacking. Herein, we demonstrate for the first time that mucin diffusivity (∼1/viscosity) increases as a function of [HCO(3)(-)]. Direct measurements of exocytosed mucin-swelling kinetics from airway cells showed that mucin diffusivity increases by ∼300% with 20 mM extracellular HCO(3)(-) concentration. Supporting data indicate that HCO(3)(-) reduces free Ca(2+) concentration and decreases the amount of Ca(2+) that remains associated with mucins. The results demonstrate that HCO(3)(-) enhances mucin swelling and hydration by reducing Ca(2+) cross-linking in mucins, thereby decreasing its viscosity and likely increasing its transportability. In addition, HCO(3)(-) can function as a Ca(2+) chelator like EGTA to disperse mucin aggregates. This study indicates that poor HCO(3)(-) availability in CF may explain why secreted mucus remains aggregated and more viscous in affected organs. These insights bear on not only the fundamental pathogenesis in CF, but also on the process of gel mucus formation and release in general.
Collapse
Affiliation(s)
- Eric Y T Chen
- Bioengineering, Univ. of California at Merced, 95343, USA
| | | | | | | |
Collapse
|