101
|
Epithelial Anion Transport as Modulator of Chemokine Signaling. Mediators Inflamm 2016; 2016:7596531. [PMID: 27382190 PMCID: PMC4921137 DOI: 10.1155/2016/7596531] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 05/03/2016] [Accepted: 05/12/2016] [Indexed: 12/16/2022] Open
Abstract
The pivotal role of epithelial cells is to secrete and absorb ions and water in order to allow the formation of a luminal fluid compartment that is fundamental for the epithelial function as a barrier against environmental factors. Importantly, epithelial cells also take part in the innate immune system. As a first line of defense they detect pathogens and react by secreting and responding to chemokines and cytokines, thus aggravating immune responses or resolving inflammatory states. Loss of epithelial anion transport is well documented in a variety of diseases including cystic fibrosis, chronic obstructive pulmonary disease, asthma, pancreatitis, and cholestatic liver disease. Here we review the effect of aberrant anion secretion with focus on the release of inflammatory mediators by epithelial cells and discuss putative mechanisms linking these transport defects to the augmented epithelial release of chemokines and cytokines. These mechanisms may contribute to the excessive and persistent inflammation in many respiratory and gastrointestinal diseases.
Collapse
|
102
|
Kim N, Duncan GA, Hanes J, Suk JS. Barriers to inhaled gene therapy of obstructive lung diseases: A review. J Control Release 2016; 240:465-488. [PMID: 27196742 DOI: 10.1016/j.jconrel.2016.05.031] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 05/11/2016] [Accepted: 05/12/2016] [Indexed: 12/29/2022]
Abstract
Knowledge of genetic origins of obstructive lung diseases has made inhaled gene therapy an attractive alternative to the current standards of care that are limited to managing disease symptoms. Initial lung gene therapy clinical trials occurred in the early 1990s following the discovery of the genetic defect responsible for cystic fibrosis (CF), a monogenic disorder. However, despite over two decades of intensive effort, gene therapy has yet to help patients with CF or any other obstructive lung disease. The slow progress is due in part to poor understanding of the biological barriers to inhaled gene therapy. Encouragingly, clinical trials have shown that inhaled gene therapy with various viral vectors and non-viral gene vectors is well tolerated by patients, and continued research has provided valuable lessons and resources that may lead to future success of this therapeutic strategy. In this review, we first introduce representative obstructive lung diseases and examine limitations of currently available therapeutic options. We then review key components for successful execution of inhaled gene therapy, including gene delivery systems, primary physiological barriers and strategies to overcome them, and advances in preclinical disease models with which the most promising systems may be identified for human clinical trials.
Collapse
Affiliation(s)
- Namho Kim
- The Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Gregg A Duncan
- The Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Justin Hanes
- The Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Environmental and Health Sciences, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Neurosurgery, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Jung Soo Suk
- The Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA.
| |
Collapse
|
103
|
Meyerholz DK. Lessons learned from the cystic fibrosis pig. Theriogenology 2016; 86:427-32. [PMID: 27142487 DOI: 10.1016/j.theriogenology.2016.04.057] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 12/14/2015] [Accepted: 03/14/2016] [Indexed: 12/01/2022]
Abstract
Deficient function in the anion channel cystic fibrosis (CF) transmembrane conductance regulator is the fundamental cause for CF. This is a monogenic condition that causes lesions in several organs including the respiratory tract, pancreas, liver, intestines, and reproductive tract. Lung disease is most notable, given it is the leading cause of morbidity and mortality in people with CF. Shortly after the identification of CF transmembrane conductance regulator, CF mouse models were developed that did not show spontaneous lung disease as seen in humans, and this spurred development of additional CF animal models. Pig models were considered a leading choice for several reasons including their similarity to humans in respiratory anatomy, physiology, and in size for translational imaging. The first CF pig models were reported in 2008 and have been extremely valuable to help clarify persistent questions in the field and advance understanding of disease pathogenesis. Because CF pigs are susceptible to lung disease like humans, they have direct utility in translational research. In addition, CF pig models are useful to compare and contrast with current CF mouse models, human clinical studies, and even newer CF animal models being characterized. This "triangulation" strategy could help identify genetic differences that underlie phenotypic variations, so as to focus and accelerate translational research.
Collapse
Affiliation(s)
- David K Meyerholz
- Department of Pathology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.
| |
Collapse
|
104
|
Decreased Expression of Enterocyte Nutrient Assimilation Genes and Proteins in the Small Intestine of Cystic Fibrosis Mouse. J Pediatr Gastroenterol Nutr 2016; 62:627-34. [PMID: 26551319 DOI: 10.1097/mpg.0000000000001030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
OBJECTIVES Cystic fibrosis (CF) has major effects on the intestinal tract with potential consequences on nutrition, but these are not fully understood. I investigated the possibility of altered enterocyte maturation in CF, as suggested by decreased enterocyte nutrient assimilation gene expression in published transcriptome analysis of the small intestine of CF mouse. METHODS In CF and wild-type (WT) mice, enterocyte gene/protein expression was analyzed by quantitative realtime polymerase chain reaction (qRT-PCR), enzyme histochemistry, immunohistochemistry, and Western blot. One group of mice was maintained on a control liquid diet; to manipulate the gut microbiota, a second group was treated with oral antibiotics; to improve hydration of the gut lumen, a third group was given a laxative drinking solution. RESULTS On the control diet in the CF intestine, there were decreased levels (67%-85% reduction of WT levels) of enterocyte genes/proteins. Antibiotics did not normalize the expression of enterocyte markers in the CF mouse. In contrast, the laxative treatment of CF mice significantly increased expression to near WT levels. CONCLUSIONS These studies suggest that the environment of the CF intestinal lumen plays a role in reduced maturation of enterocytes. Because changing the gut lumen environment can affect enterocyte maturation, this is not a cell-autonomous effect of loss of CF transmembrane conductance regulator.
Collapse
|
105
|
Birket SE, Chu KK, Houser GH, Liu L, Fernandez CM, Solomon GM, Lin V, Shastry S, Mazur M, Sloane PA, Hanes J, Grizzle WE, Sorscher EJ, Tearney GJ, Rowe SM. Combination therapy with cystic fibrosis transmembrane conductance regulator modulators augment the airway functional microanatomy. Am J Physiol Lung Cell Mol Physiol 2016; 310:L928-39. [PMID: 26968770 DOI: 10.1152/ajplung.00395.2015] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 03/08/2016] [Indexed: 11/22/2022] Open
Abstract
Recently approved therapies that modulate CFTR function have shown significant clinical benefit, but recent investigations regarding their molecular mechanism when used in combination have not been consistent with clinical results. We employed micro-optical coherence tomography as a novel means to assess the mechanism of action of CFTR modulators, focusing on the effects on mucociliary clearance. Primary human airway monolayers from patients with a G551D mutation responded to ivacaftor treatment with increased ion transport, airway surface liquid depth, ciliary beat frequency, and mucociliary transport rate, in addition to decreased effective viscosity of the mucus layer, a unique mechanism established by our findings. These endpoints are consistent with the benefit observed in G551D patients treated with ivacaftor, and identify a novel mechanism involving mucus viscosity. In monolayers derived from F508del patients, the situation is more complicated, compounded by disparate effects on CFTR expression and function. However, by combining ion transport measurements with functional imaging, we establish a crucial link between in vitro data and clinical benefit, a finding not explained by ion transport studies alone. We establish that F508del cells exhibit increased mucociliary transport and decreased mucus effective viscosity, but only when ivacaftor is added to the regimen. We further show that improvement in the functional microanatomy in vitro corresponds with lung function benefit observed in the clinical trials, whereas ion transport in vitro corresponds to changes in sweat chloride. Functional imaging reveals insights into clinical efficacy and CFTR biology that significantly impact our understanding of novel therapies.
Collapse
Affiliation(s)
- Susan E Birket
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Kengyeh K Chu
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts; Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts; Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts; and
| | - Grace H Houser
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Linbo Liu
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts; Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts
| | - Courtney M Fernandez
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - George M Solomon
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Vivian Lin
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Suresh Shastry
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Marina Mazur
- Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama
| | - Peter A Sloane
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Justin Hanes
- Center for Nanomedicine, Department of Ophthalmology, and Department of Neurosurgery, Johns Hopkins Hospital, Baltimore, Maryland
| | - William E Grizzle
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Eric J Sorscher
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama
| | - Guillermo J Tearney
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts; Harvard Medical School, Boston, Massachusetts; Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts; Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts; and
| | - Steven M Rowe
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama; Department of Cellular, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama;
| |
Collapse
|
106
|
Walker NM, Liu J, Stein SR, Stefanski CD, Strubberg AM, Clarke LL. Cellular chloride and bicarbonate retention alters intracellular pH regulation in Cftr KO crypt epithelium. Am J Physiol Gastrointest Liver Physiol 2016; 310:G70-80. [PMID: 26542396 PMCID: PMC4719062 DOI: 10.1152/ajpgi.00236.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 10/29/2015] [Indexed: 01/31/2023]
Abstract
Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR), an anion channel providing a major pathway for Cl(-) and HCO3 (-) efflux across the apical membrane of the epithelium. In the intestine, CF manifests as obstructive syndromes, dysbiosis, inflammation, and an increased risk for gastrointestinal cancer. Cftr knockout (KO) mice recapitulate CF intestinal disease, including intestinal hyperproliferation. Previous studies using Cftr KO intestinal organoids (enteroids) indicate that crypt epithelium maintains an alkaline intracellular pH (pHi). We hypothesized that Cftr has a cell-autonomous role in downregulating pHi that is incompletely compensated by acid-base regulation in its absence. Here, 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein microfluorimetry of enteroids showed that Cftr KO crypt epithelium sustains an alkaline pHi and resistance to cell acidification relative to wild-type. Quantitative real-time PCR revealed that Cftr KO enteroids exhibit downregulated transcription of base (HCO3 (-))-loading proteins and upregulation of the basolateral membrane HCO3 (-)-unloader anion exchanger 2 (Ae2). Although Cftr KO crypt epithelium had increased Ae2 expression and Ae2-mediated Cl(-)/HCO3 (-) exchange with maximized gradients, it also had increased intracellular Cl(-) concentration relative to wild-type. Pharmacological reduction of intracellular Cl(-) concentration in Cftr KO crypt epithelium normalized pHi, which was largely Ae2-dependent. We conclude that Cftr KO crypt epithelium maintains an alkaline pHi as a consequence of losing both Cl(-) and HCO3 (-) efflux, which impairs pHi regulation by Ae2. Retention of Cl(-) and an alkaline pHi in crypt epithelium may alter several cellular processes in the proliferative compartment of Cftr KO intestine.
Collapse
Affiliation(s)
- Nancy M. Walker
- 1Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; and
| | - Jinghua Liu
- 1Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; and
| | - Sydney R. Stein
- 1Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; and
| | - Casey D. Stefanski
- 1Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; and ,2Department of Biomedical Sciences, University of Missouri, Columbia, Missouri
| | - Ashlee M. Strubberg
- 1Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; and ,2Department of Biomedical Sciences, University of Missouri, Columbia, Missouri
| | - Lane L. Clarke
- 1Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; and ,2Department of Biomedical Sciences, University of Missouri, Columbia, Missouri
| |
Collapse
|
107
|
Hegyi P, Wilschanski M, Muallem S, Lukacs GL, Sahin-Tóth M, Uc A, Gray MA, Rakonczay Z, Maléth J. CFTR: A New Horizon in the Pathomechanism and Treatment of Pancreatitis. Rev Physiol Biochem Pharmacol 2016; 170:37-66. [PMID: 26856995 DOI: 10.1007/112_2015_5002] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) is an ion channel that conducts chloride and bicarbonate ions across epithelial cell membranes. Mutations in the CFTR gene diminish the ion channel function and lead to impaired epithelial fluid transport in multiple organs such as the lung and the pancreas resulting in cystic fibrosis. Heterozygous carriers of CFTR mutations do not develop cystic fibrosis but exhibit increased risk for pancreatitis and associated pancreatic damage characterized by elevated mucus levels, fibrosis, and cyst formation. Importantly, recent studies demonstrated that pancreatitis causing insults, such as alcohol, smoking, or bile acids, strongly inhibit CFTR function. Furthermore, human studies showed reduced levels of CFTR expression and function in all forms of pancreatitis. These findings indicate that impairment of CFTR is critical in the development of pancreatitis; therefore, correcting CFTR function could be the first specific therapy in pancreatitis. In this review, we summarize recent advances in the field and discuss new possibilities for the treatment of pancreatitis.
Collapse
Affiliation(s)
- Péter Hegyi
- Institute for Translational Medicine and 1st Department of Medicine, University of Pécs, Pécs, Hungary.
- MTA-SZTE Translational Gastroenterology Research Group, Szeged, Hungary.
- First Department of Medicine, University of Szeged, Szeged, Hungary.
| | - Michael Wilschanski
- Pediatric Gastroenterology Unit, Hadassah Medical Center, Hebrew University, Jerusalem, Israel
| | - Shmuel Muallem
- National Institute of Dental and Craniofacial Research, Bethesda, MD, USA
| | | | - Miklós Sahin-Tóth
- Department of Molecular and Cell Biology, Boston University Henry M. Goldman School of Dental Medicine, Boston, MA, USA
| | - Aliye Uc
- Department of Pediatrics, University of Iowa, Carver College of Medicine, Iowa City, IA, USA
| | - Michael A Gray
- Institute for Cell & Molecular Biosciences, University Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Zoltán Rakonczay
- First Department of Medicine, University of Szeged, Szeged, Hungary
- Department of Pathophysiology, University of Szeged, Szeged, Hungary
| | - József Maléth
- First Department of Medicine, University of Szeged, Szeged, Hungary
- MTA-SZTE Translational Gastroenterology Research Group, Szeged, Hungary
| |
Collapse
|
108
|
Klymiuk N, Seeliger F, Bohlooly-Y M, Blutke A, Rudmann DG, Wolf E. Tailored Pig Models for Preclinical Efficacy and Safety Testing of Targeted Therapies. Toxicol Pathol 2015; 44:346-57. [PMID: 26511847 DOI: 10.1177/0192623315609688] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Despite enormous advances in translational biomedical research, there remains a growing demand for improved animal models of human disease. This is particularly true for diseases where rodent models do not reflect the human disease phenotype. Compared to rodents, pig anatomy and physiology are more similar to humans in cardiovascular, immune, respiratory, skeletal muscle, and metabolic systems. Importantly, efficient and precise techniques for genetic engineering of pigs are now available, facilitating the creation of tailored large animal models that mimic human disease mechanisms at the molecular level. In this article, the benefits of genetically engineered pigs for basic and translational research are exemplified by a novel pig model of Duchenne muscular dystrophy and by porcine models of cystic fibrosis. Particular emphasis is given to potential advantages of using these models for efficacy and safety testing of targeted therapies, such as exon skipping and gene editing, for example, using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated system. In general, genetically tailored pig models have the potential to bridge the gap between proof-of-concept studies in rodents and clinical trials in patients, thus supporting translational medicine.
Collapse
Affiliation(s)
- Nikolai Klymiuk
- Gene Center and Center for Innovative Medical Models (CiMM), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Frank Seeliger
- Pathology Science, DSM, Transgenic, AstraZeneca RD, Mölndal, Sweden
| | | | - Andreas Blutke
- Institute of Veterinary Pathology, Center for Clinical Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Daniel G Rudmann
- Pathology Science, DSM, Transgenic, AstraZeneca RD, Mölndal, Sweden
| | - Eckhard Wolf
- Gene Center and Center for Innovative Medical Models (CiMM), Ludwig-Maximilians-Universität München, Munich, Germany
| |
Collapse
|
109
|
Abstract
Submucosal glands contribute to airway surface liquid (ASL), a film that protects all airway surfaces. Glandular mucus comprises electrolytes, water, the gel-forming mucin MUC5B, and hundreds of different proteins with diverse protective functions. Gland volume per unit area of mucosal surface correlates positively with impaction rate of inhaled particles. In human main bronchi, the volume of the glands is ∼ 50 times that of surface goblet cells, but the glands diminish in size and frequency distally. ASL and its trapped particles are removed from the airways by mucociliary transport. Airway glands have a tubuloacinar structure, with a single terminal duct, a nonciliated collecting duct, then branching secretory tubules lined with mucous cells and ending in serous acini. They allow for a massive increase in numbers of mucus-producing cells without replacing surface ciliated cells. Active secretion of Cl(-) and HCO3 (-) by serous cells produces most of the fluid of gland secretions. Glands are densely innervated by tonically active, mutually excitatory airway intrinsic neurons. Most gland mucus is secreted constitutively in vivo, with large, transient increases produced by emergency reflex drive from the vagus. Elevations of [cAMP]i and [Ca(2+)]i coordinate electrolyte and macromolecular secretion and probably occur together for baseline activity in vivo, with cholinergic elevation of [Ca(2+)]i being mainly responsive for transient increases in secretion. Altered submucosal gland function contributes to the pathology of all obstructive diseases, but is an early stage of pathogenesis only in cystic fibrosis.
Collapse
Affiliation(s)
- Jonathan H Widdicombe
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, California; and Department of Psychology and Cystic Fibrosis Research Laboratory, Stanford University, Stanford, California
| | - Jeffrey J Wine
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, California; and Department of Psychology and Cystic Fibrosis Research Laboratory, Stanford University, Stanford, California
| |
Collapse
|
110
|
Gibson-Corley KN, Meyerholz DK, Engelhardt JF. Pancreatic pathophysiology in cystic fibrosis. J Pathol 2015; 238:311-20. [PMID: 26365583 DOI: 10.1002/path.4634] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 09/04/2015] [Accepted: 09/08/2015] [Indexed: 12/28/2022]
Abstract
The pancreas is one of the earliest, and most commonly affected, organs in patients with cystic fibrosis (CF). Studying the pathogenesis of pancreatic disease is limited in CF patients, due to its early clinical onset, co-morbidities and lack of tissue samples from the early phases of disease. In recent years, several new CF animal models have been developed that have advanced our understanding of both CF exocrine and endocrine pancreatic disease. Additionally, these models have helped us to better define the influence of pancreatic lesions on CF disease progression in other organs, such as the gastrointestinal tract and lung.
Collapse
Affiliation(s)
| | - David K Meyerholz
- Department of Pathology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - John F Engelhardt
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| |
Collapse
|
111
|
Abstract
Cystic fibrosis is an autosomal recessive, monogenetic disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The gene defect was first described 25 years ago and much progress has been made since then in our understanding of how CFTR mutations cause disease and how this can be addressed therapeutically. CFTR is a transmembrane protein that transports ions across the surface of epithelial cells. CFTR dysfunction affects many organs; however, lung disease is responsible for the vast majority of morbidity and mortality in patients with cystic fibrosis. Prenatal diagnostics, newborn screening and new treatment algorithms are changing the incidence and the prevalence of the disease. Until recently, the standard of care in cystic fibrosis treatment focused on preventing and treating complications of the disease; now, novel treatment strategies directly targeting the ion channel abnormality are becoming available and it will be important to evaluate how these treatments affect disease progression and the quality of life of patients. In this Primer, we summarize the current knowledge, and provide an outlook on how cystic fibrosis clinical care and research will be affected by new knowledge and therapeutic options in the near future. For an illustrated summary of this Primer, visit: http://go.nature.com/4VrefN.
Collapse
|
112
|
Cai Z, Palmai-Pallag T, Khuituan P, Mutolo MJ, Boinot C, Liu B, Scott-Ward TS, Callebaut I, Harris A, Sheppard DN. Impact of the F508del mutation on ovine CFTR, a Cl- channel with enhanced conductance and ATP-dependent gating. J Physiol 2015; 593:2427-46. [PMID: 25763566 DOI: 10.1113/jp270227] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 03/02/2015] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS Malfunction of the cystic fibrosis transmembrane conductance regulator (CFTR), a gated pathway for chloride movement, causes the common life-shortening genetic disease cystic fibrosis (CF). Towards the development of a sheep model of CF, we have investigated the function of sheep CFTR. We found that sheep CFTR was noticeably more active than human CFTR, while the most common CF mutation, F508del, had reduced impact on sheep CFTR function. Our results demonstrate that subtle changes in protein structure have marked effects on CFTR function and the consequences of the CF mutation F508del. ABSTRACT Cross-species comparative studies are a powerful approach to understanding the epithelial Cl(-) channel cystic fibrosis transmembrane conductance regulator (CFTR), which is defective in the genetic disease cystic fibrosis (CF). Here, we investigate the single-channel behaviour of ovine CFTR and the impact of the most common CF mutation, F508del-CFTR, using excised inside-out membrane patches from transiently transfected CHO cells. Like human CFTR, ovine CFTR formed a weakly inwardly rectifying Cl(-) channel regulated by PKA-dependent phosphorylation, inhibited by the open-channel blocker glibenclamide. However, for three reasons, ovine CFTR was noticeably more active than human CFTR. First, single-channel conductance was increased. Second, open probability was augmented because the frequency and duration of channel openings were increased. Third, with enhanced affinity and efficacy, ATP more strongly stimulated ovine CFTR channel gating. Consistent with these data, the CFTR modulator phloxine B failed to potentiate ovine CFTR Cl(-) currents. Similar to its impact on human CFTR, the F508del mutation caused a temperature-sensitive folding defect, which disrupted ovine CFTR protein processing and reduced membrane stability. However, the F508del mutation had reduced impact on ovine CFTR channel gating in contrast to its marked effects on human CFTR. We conclude that ovine CFTR forms a regulated Cl(-) channel with enhanced conductance and ATP-dependent channel gating. This phylogenetic analysis of CFTR structure and function demonstrates that subtle changes in structure have pronounced effects on channel function and the consequences of the CF mutation F508del.
Collapse
Affiliation(s)
- Zhiwei Cai
- School of Physiology and Pharmacology, University of Bristol, Medical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Timea Palmai-Pallag
- Human Molecular Genetics Program, Lurie Children's Research Center and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60614, USA.,Harris Laboratory, formerly at the Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Pissared Khuituan
- School of Physiology and Pharmacology, University of Bristol, Medical Sciences Building, University Walk, Bristol, BS8 1TD, UK.,Center of Calcium and Bone Research, Department of Physiology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Michael J Mutolo
- Human Molecular Genetics Program, Lurie Children's Research Center and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60614, USA
| | - Clément Boinot
- Institut de Physiologie et Biologie Cellulaires, Université de Poitiers, CNRS FRE 3511, 86022, Poitiers, France
| | - Beihui Liu
- School of Physiology and Pharmacology, University of Bristol, Medical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Toby S Scott-Ward
- School of Physiology and Pharmacology, University of Bristol, Medical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Isabelle Callebaut
- IMPMC, Sorbonne Universités - UPMC Univ Paris 06, UMR CNRS 7590, Museum National d'Histoire Naturelle, IRD UMR 206, IUC, 75005, Paris, France
| | - Ann Harris
- Human Molecular Genetics Program, Lurie Children's Research Center and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL, 60614, USA
| | - David N Sheppard
- School of Physiology and Pharmacology, University of Bristol, Medical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| |
Collapse
|
113
|
Diwakar A, Adam RJ, Michalski AS, Tamegnon MM, Fischer AJ, Launspach JL, Horan RA, Kao SC, Chaloner K, Meyerholz DK, Stoltz DA. Sonographic evidence of abnormal tracheal cartilage ring structure in cystic fibrosis. Laryngoscope 2015; 125:2398-404. [PMID: 25827636 DOI: 10.1002/lary.25255] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 01/13/2015] [Accepted: 02/18/2015] [Indexed: 11/10/2022]
Abstract
OBJECTIVES/HYPOTHESIS Tracheal cartilage ring structural abnormalities have been reported in cystic fibrosis (CF) mice and pigs. Whether similar findings are present in humans with CF is unknown. We hypothesized that tracheal cartilage ring shape and size would be different in people with CF. STUDY DESIGN Tracheal cartilage ring size and shape were measured in adults with (n = 21) and without CF (n = 18). METHODS Ultrasonography was used in human subjects to noninvasively assess tracheal cartilage ring structure in both the sagittal and the transverse planes. Tracheal cartilage ring thickness was also determined from histological sections obtained from newborn non-CF and CF pigs. These values were compared with human data. RESULTS Human CF tracheas had a greater width and were less circular in shape compared to non-CF subjects. CF tracheal cartilage rings had a greater midline cross-sectional area and were thicker compared to non-CF rings. Maximal tracheal cartilage ring thickness was also greater in both newborn CF pigs and human adults with CF, compared to non-CF controls. CONCLUSIONS Our findings demonstrate that structural differences exist in tracheal cartilage rings in adults with CF. Comparison with newborn CF pig data suggests that some of these changes may be congenital in nature. LEVEL OF EVIDENCE 3b
Collapse
Affiliation(s)
- Amit Diwakar
- Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
| | - Ryan J Adam
- Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa.,Department of Biomedical Engineering, College of Engineering, University of Iowa, Iowa City, Iowa
| | - Andrew S Michalski
- Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
| | - Monelle M Tamegnon
- Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, Iowa, U.S.A
| | - Anthony J Fischer
- Department of Pediatrics, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
| | - Jan L Launspach
- Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
| | - Rebecca A Horan
- Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
| | - Simon C Kao
- Department of Radiology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
| | - Kathryn Chaloner
- Department of Biostatistics, College of Public Health, University of Iowa, Iowa City, Iowa, U.S.A
| | - David K Meyerholz
- Department of Pathology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa
| | - David A Stoltz
- Department of Internal Medicine, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa.,Department of Molecular Physiology and Biophysics, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa.,Department of Biomedical Engineering, College of Engineering, University of Iowa, Iowa City, Iowa
| |
Collapse
|
114
|
Olivier AK, Gibson-Corley KN, Meyerholz DK. Animal models of gastrointestinal and liver diseases. Animal models of cystic fibrosis: gastrointestinal, pancreatic, and hepatobiliary disease and pathophysiology. Am J Physiol Gastrointest Liver Physiol 2015; 308:G459-71. [PMID: 25591863 PMCID: PMC4360044 DOI: 10.1152/ajpgi.00146.2014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Multiple organ systems, including the gastrointestinal tract, pancreas, and hepatobiliary systems, are affected by cystic fibrosis (CF). Many of these changes begin early in life and are difficult to study in young CF patients. Recent development of novel CF animal models has expanded opportunities in the field to better understand CF pathogenesis and evaluate traditional and innovative therapeutics. In this review, we discuss manifestations of CF disease in gastrointestinal, pancreatic, and hepatobiliary systems of humans and animal models. We also compare the similarities and limitations of animal models and discuss future directions for modeling CF.
Collapse
Affiliation(s)
- Alicia K. Olivier
- Department of Pathology and Center for Gene Therapy of Cystic Fibrosis and Other Genetic Diseases, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Katherine N. Gibson-Corley
- Department of Pathology and Center for Gene Therapy of Cystic Fibrosis and Other Genetic Diseases, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - David K. Meyerholz
- Department of Pathology and Center for Gene Therapy of Cystic Fibrosis and Other Genetic Diseases, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| |
Collapse
|
115
|
Hiemstra PS, McCray PB, Bals R. The innate immune function of airway epithelial cells in inflammatory lung disease. Eur Respir J 2015; 45:1150-62. [PMID: 25700381 DOI: 10.1183/09031936.00141514] [Citation(s) in RCA: 273] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The airway epithelium is now considered to be central to the orchestration of pulmonary inflammatory and immune responses, and is also key to tissue remodelling. It acts as the first barrier in the defence against a wide range of inhaled challenges, and is critically involved in the regulation of both innate and adaptive immune responses to these challenges. Recent progress in our understanding of the developmental regulation of this tissue, the differentiation pathways, recognition of pathogens and antimicrobial responses is now exploited to help understand how epithelial cell function and dysfunction contributes to the pathogenesis of a variety of inflammatory lung diseases. Herein, advances in our knowledge of the biology of airway epithelium, as well as its role and (dys)function in asthma, chronic obstructive pulmonary fibrosis and cystic fibrosis will be discussed.
Collapse
Affiliation(s)
- Pieter S Hiemstra
- Dept of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Paul B McCray
- Dept of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Robert Bals
- Dept of Internal Medicine V - Pulmonology, Allergology and Critical Care Medicine, Saarland University, Homburg, Germany
| |
Collapse
|
116
|
Affiliation(s)
- David A Stoltz
- Department of Internal Medicine, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
- Department of Molecular Physiology and Biophysics, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
- Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa 52242
| | - David K Meyerholz
- Department of Pathology, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Michael J Welsh
- Department of Internal Medicine, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
- Department of Molecular Physiology and Biophysics, Roy J and Lucille A Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
- Howard Hughes Medical Institute, Roy J and Lucille A Carver College of Medicine University of Iowa, Iowa City, Iowa 52242
| |
Collapse
|
117
|
Bronckers ALJJ, Lyaruu DM, Guo J, Bijvelds MJC, Bervoets TJM, Zandieh-Doulabi B, Medina JF, Li Z, Zhang Y, DenBesten PK. Composition of mineralizing incisor enamel in cystic fibrosis transmembrane conductance regulator-deficient mice. Eur J Oral Sci 2014; 123:9-16. [PMID: 25557910 DOI: 10.1111/eos.12163] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/28/2014] [Indexed: 12/25/2022]
Abstract
Formation of crystals in the enamel space releases protons that need to be buffered to sustain mineral accretion. We hypothesized that apical cystic fibrosis transmembrane conductance regulator (CFTR) in maturation ameloblasts transduces chloride into forming enamel as a critical step to secrete bicarbonates. We tested this by determining the calcium, chloride, and fluoride levels in developing enamel of Cftr-null mice by quantitative electron probe microanalysis. Maturation-stage enamel from Cftr-null mice contained less chloride and calcium than did wild-type enamel, was more acidic when stained with pH dyes ex vivo, and formed no fluorescent modulation bands after in vivo injection of the mice with calcein. To acidify the enamel further we exposed Cftr-null mice to fluoride in drinking water to stimulate proton release during formation of hypermineralized lines. In Cftr-deficient mice, fluoride further lowered enamel calcium without further reducing chloride levels. The data support the view that apical CFTR in maturation ameloblasts tranduces chloride into developing enamel as part of the machinery to buffer protons released during mineral accretion.
Collapse
Affiliation(s)
- Antonius L J J Bronckers
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute, University of Amsterdam and VU University Amsterdam, Amsterdam, the Netherlands
| | | | | | | | | | | | | | | | | | | |
Collapse
|
118
|
Abstract
The availability of the human genome sequence and tools for interrogating individual genomes provide an unprecedented opportunity to apply genetics to medicine. Mendelian conditions, which are caused by dysfunction of a single gene, offer powerful examples that illustrate how genetics can provide insights into disease. Cystic fibrosis, one of the more common lethal autosomal recessive Mendelian disorders, is presented here as an example. Recent progress in elucidating disease mechanism and causes of phenotypic variation, as well as in the development of treatments, demonstrates that genetics continues to play an important part in cystic fibrosis research 25 years after the discovery of the disease-causing gene.
Collapse
|
119
|
Hill AE, Plyler ZE, Tiwari H, Patki A, Tully JP, McAtee CW, Moseley LA, Sorscher EJ. Longevity and plasticity of CFTR provide an argument for noncanonical SNP organization in hominid DNA. PLoS One 2014; 9:e109186. [PMID: 25350658 PMCID: PMC4211684 DOI: 10.1371/journal.pone.0109186] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 09/09/2014] [Indexed: 12/03/2022] Open
Abstract
Like many other ancient genes, the cystic fibrosis transmembrane conductance regulator (CFTR) has survived for hundreds of millions of years. In this report, we consider whether such prodigious longevity of an individual gene – as opposed to an entire genome or species – should be considered surprising in the face of eons of relentless DNA replication errors, mutagenesis, and other causes of sequence polymorphism. The conventions that modern human SNP patterns result either from purifying selection or random (neutral) drift were not well supported, since extant models account rather poorly for the known plasticity and function (or the established SNP distributions) found in a multitude of genes such as CFTR. Instead, our analysis can be taken as a polemic indicating that SNPs in CFTR and many other mammalian genes may have been generated—and continue to accrue—in a fundamentally more organized manner than would otherwise have been expected. The resulting viewpoint contradicts earlier claims of ‘directional’ or ‘intelligent design-type’ SNP formation, and has important implications regarding the pace of DNA adaptation, the genesis of conserved non-coding DNA, and the extent to which eukaryotic SNP formation should be viewed as adaptive.
Collapse
Affiliation(s)
- Aubrey E. Hill
- Department of Computer and Information Sciences, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Zackery E. Plyler
- Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Hemant Tiwari
- Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Amit Patki
- Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Joel P. Tully
- Department of Computer and Information Sciences, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Christopher W. McAtee
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Leah A. Moseley
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Eric J. Sorscher
- Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- * E-mail:
| |
Collapse
|
120
|
Birket SE, Chu KK, Liu L, Houser GH, Diephuis BJ, Wilsterman EJ, Dierksen G, Mazur M, Shastry S, Li Y, Watson JD, Smith AT, Schuster BS, Hanes J, Grizzle WE, Sorscher EJ, Tearney GJ, Rowe SM. A functional anatomic defect of the cystic fibrosis airway. Am J Respir Crit Care Med 2014; 190:421-32. [PMID: 25029666 DOI: 10.1164/rccm.201404-0670oc] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE The mechanisms underlying cystic fibrosis (CF) lung disease pathogenesis are unknown. OBJECTIVES To establish mechanisms linking anion transport with the functional microanatomy, we evaluated normal and CF piglet trachea as well as adult swine trachea in the presence of selective anion inhibitors. METHODS We investigated airway functional microanatomy using microoptical coherence tomography, a new imaging modality that concurrently quantifies multiple functional parameters of airway epithelium in a colocalized fashion. MEASUREMENTS AND MAIN RESULTS Tracheal explants from wild-type swine demonstrated a direct link between periciliary liquid (PCL) hydration and mucociliary transport (MCT) rates, a relationship frequently invoked but never experimentally confirmed. However, in CF airways this relationship was completely disrupted, with greater PCL depths associated with slowest transport rates. This disrupted relationship was recapitulated by selectively inhibiting bicarbonate transport in vitro and ex vivo. CF mucus exhibited increased viscosity in situ due to the absence of bicarbonate transport, explaining defective MCT that occurs even in the presence of adequate PCL hydration. CONCLUSIONS An inherent defect in CF airway surface liquid contributes to delayed MCT beyond that caused by airway dehydration alone and identifies a fundamental mechanism underlying the pathogenesis of CF lung disease in the absence of antecedent infection or inflammation.
Collapse
|