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Jaramillo AM, Vladar EK, Holguin F, Dickey BF, Evans CM. Emerging cell and molecular targets for treating mucus hypersecretion in asthma. Allergol Int 2024; 73:375-381. [PMID: 38692992 DOI: 10.1016/j.alit.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Accepted: 04/03/2024] [Indexed: 05/03/2024] Open
Abstract
Mucus provides a protective barrier that is crucial for host defense in the lungs. However, excessive or abnormal mucus can have pathophysiological consequences in many pulmonary diseases, including asthma. Patients with asthma are treated with agents that relax airway smooth muscle and reduce airway inflammation, but responses are often inadequate. In part, this is due to the inability of existing therapeutic agents to directly target mucus. Accordingly, there is a critical need to better understand how mucus hypersecretion and airway plugging are affected by the epithelial cells that synthesize, secrete, and transport mucus components. This review highlights recent advances in the biology of mucin glycoproteins with a specific focus on MUC5AC and MUC5B, the chief macromolecular components of airway mucus. An improved mechanistic understanding of key steps in mucin production and secretion will help reveal novel potential therapeutic strategies.
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Affiliation(s)
- Ana M Jaramillo
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | - Eszter K Vladar
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | - Fernando Holguin
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | - Burton F Dickey
- Department of Pulmonary Medicine, Anderson Cancer Center, University of Texas M.D., Houston, TX, USA
| | - Christopher M Evans
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado School of Medicine, Aurora, CO, USA.
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2
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Faruque MRJ, Taidouch K, Bikker FJ, Ligtenberg AJM. Exploring the Correlation between Salivary Spinnbarkeit and Caries Scores. Caries Res 2024; 58:111-116. [PMID: 38246142 PMCID: PMC10997273 DOI: 10.1159/000536402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 01/14/2024] [Indexed: 01/23/2024] Open
Abstract
INTRODUCTION In this study, the relationship between the spinnbarkeit, i.e., the stretchability of saliva, and dental caries was investigated. METHODS Dentistry students were divided into a group with more than 2 decayed, missed, and filled teeth (DMFT ≥2, n = 30) and caries-free group (DMFT = 0, n = 36). RESULTS Unstimulated saliva flow rate, pH, and spinnbarkeit were determined. Salivary spinnbarkeit was significantly lower in the caries-prone group compared to the caries-free group (5.4 ± 3.9 mm vs. 13.5 ± 7.6 mm, respectively, p < 0.001). CONCLUSION This suggests that saliva with high spinnbarkeit protects better against dental caries.
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Affiliation(s)
- Mouri R J Faruque
- Oral Biochemistry, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands
| | - Kawtar Taidouch
- Oral Biochemistry, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands
| | - Floris J Bikker
- Oral Biochemistry, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands
| | - Antoon J M Ligtenberg
- Oral Biochemistry, Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands
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3
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Denneny E, Sahota J, Beatson R, Thornton D, Burchell J, Porter J. Mucins and their receptors in chronic lung disease. Clin Transl Immunology 2020; 9:e01120. [PMID: 32194962 PMCID: PMC7077995 DOI: 10.1002/cti2.1120] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 02/12/2020] [Accepted: 02/27/2020] [Indexed: 12/11/2022] Open
Abstract
There is growing recognition that mucus and mucin biology have a considerable impact on respiratory health, and subsequent global morbidity and mortality. Mucins play a critical role in chronic lung disease, not only by providing a physical barrier and clearing pathogens, but also in immune homeostasis. The aim of this review is to familiarise the reader with the role of mucins in both lung health and disease, with particular focus on function in immunity, infection and inflammation. We will also discuss their receptors, termed glycan-binding proteins, and how they provide an attractive prospect for therapeutic intervention.
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Affiliation(s)
- Emma Denneny
- Leukocyte Trafficking Laboratory Centre for Inflammation and Tissue Repair UCL Respiratory Rayne Institute University College London London UK
| | - Jagdeep Sahota
- Leukocyte Trafficking Laboratory Centre for Inflammation and Tissue Repair UCL Respiratory Rayne Institute University College London London UK
| | - Richard Beatson
- Breast Cancer Biology Group Division of Cancer Studies King's College London Guy's Hospital London UK
| | - David Thornton
- Wellcome Trust Centre for Cell-Matrix Research School of Biological Sciences Faculty of Biology, Medicine and Health Manchester Academic Health Sciences Centre University of Manchester Manchester UK
| | - Joy Burchell
- Breast Cancer Biology Group Division of Cancer Studies King's College London Guy's Hospital London UK
| | - Joanna Porter
- Leukocyte Trafficking Laboratory Centre for Inflammation and Tissue Repair UCL Respiratory Rayne Institute University College London London UK
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4
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Hughes GW, Ridley C, Collins R, Roseman A, Ford R, Thornton DJ. The MUC5B mucin polymer is dominated by repeating structural motifs and its topology is regulated by calcium and pH. Sci Rep 2019; 9:17350. [PMID: 31758042 PMCID: PMC6874590 DOI: 10.1038/s41598-019-53768-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 11/01/2019] [Indexed: 01/15/2023] Open
Abstract
The polymeric mucin MUC5B provides the structural and functional framework of respiratory mucus, conferring both viscoelastic and antimicrobial properties onto this vital protective barrier. Whilst it is established that MUC5B forms disulfide-linked linear polymers, how this relates to their packaging in secretory granules, and their molecular form in mucus remain to be fully elucidated. Moreover, the role of the central heavily O-glycosylated mucin domains in MUC5B conformation is incompletely described. Here we have completed a detailed structural analysis on native MUC5B polymers purified from saliva and subsequently investigated how MUC5B conformation is affected by changes in calcium concentration and pH, factors important for mucin intragranular packaging and post-secretory expansion. The results identify that MUC5B has a beaded structure repeating along the polymer axis and suggest that these repeating motifs arise from distinct glycosylation patterns. Moreover, we demonstrate that the conformation of these highly entangled linear polymers is sensitive to calcium concentration and changes in pH. In the presence of calcium (Ca2+, 10 mM) at pH 5.0, MUC5B adopted a compact conformation which was lost either upon removal of calcium with EGTA, or by increasing the pH to 7.4. These results suggest a pathway of mucin collapse to enable intracellular packaging and mechanisms driving mucin expansion following secretion. They also point to the importance of the tight control of calcium and pH during different stages of mucin biosynthesis and secretion, and in the generation of correct mucus barrier properties.
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Affiliation(s)
- Gareth W Hughes
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK.,School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK
| | - Caroline Ridley
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK.,School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK
| | - Richard Collins
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK
| | - Alan Roseman
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK
| | - Robert Ford
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK
| | - David J Thornton
- Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK. .,Lydia Becker Institute for Immunology and Inflammation, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK. .,School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Manchester, M13 9PT, UK.
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5
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Abstract
Mucociliary clearance is a crucial component of innate defense of the lung. In respiratory diseases, such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis, mucus with abnormal properties contributes to obstruction of the airways. The failure in function of mucus in airway clearance and pathogen protection leads to chronic infection and risk of death. Polymeric mucins (MUC5AC and MUC5B) provide the structural framework of the airway mucus gel. The intracellular synthesis and assembly of these enormous, polymeric O-linked glycoproteins is a complex, multistage process involving intra- and intermolecular disulfide bond formation and extensive addition of O-glycan chains. The fully formed polymers are packaged in a highly organized and condensed form within secretory granules inside specialized secretory cells, and after the appropriate stimulus, mucins are released and expand to form mucus. This short article brings together the current knowledge on the different steps in the production of mucin polymers and the molecular mechanisms that condense them into a packaged form in secretory granules. It is by unraveling the molecular mechanisms that control intracellular mucin supramolecular structure that we might gain new insight into what determines mucus gel properties in health and disease.
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6
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Abstract
Dysregulation of gel-forming mucins is associated with many airway diseases. Better knowledge of the pathophysiological mechanisms linking mucins and respiratory diseases will advance the understanding of their pathogenesis and should provide opportunities to develop new therapeutic compounds for treatment. MUC5B and MUC5AC are the two main gel-forming mucins in the respiratory tract. The organization in domains and the expression profile of mouse Muc5b are very similar to those in humans, which makes the mouse a relevant model for studies of the translational activities of human mucins. To assess the in vivo biological functions of Muc5b, a mouse reporter tagged in frame with the green fluorescent protein marker has been engineered by homologous recombination. The proof of concept that this reporter model may be informative for translational studies was confirmed by the finding that interleukin-13 administration in living mice upregulated Muc5b production.
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7
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Demouveaux B, Gouyer V, Robbe-Masselot C, Gottrand F, Narita T, Desseyn JL. Mucin CYS domain stiffens the mucus gel hindering bacteria and spermatozoa. Sci Rep 2019; 9:16993. [PMID: 31740753 PMCID: PMC6861317 DOI: 10.1038/s41598-019-53547-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 10/31/2019] [Indexed: 12/14/2022] Open
Abstract
Mucus is the first biological barrier encountered by particles and pathogenic bacteria at the surface of secretory epithelia. The viscoelasticity of mucus is governed in part by low energy interactions that are difficult to assess. The CYS domain is a good candidate to support low energy interactions between GFMs and/or mucus constituents. Our aim was to stiffen the mucus from HT29-MTX cell cocultures and the colon of mice through the delivery of a recombinant protein made of hydrophobic CYS domains and found in multiple copies in polymeric mucins. The ability of the delivery of a poly-CYS molecule to stiffen mucus gels was assessed by probing cellular motility and particle diffusion. We demonstrated that poly-CYS enrichment decreases mucus permeability and hinders displacement of pathogenic flagellated bacteria and spermatozoa. Particle tracking microrheology showed a decrease of mucus diffusivity. The empirical obstruction scaling model evidenced a decrease of mesh size for mouse mucus enriched with poly-CYS molecules. Our data bring evidence that enrichment with a protein made of CYS domains stiffens the mucin network to provide a more impermeable and protective mucus barrier than mucus without such enrichment.
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Affiliation(s)
| | - Valérie Gouyer
- Inserm, Univ. Lille, CHU Lille, LIRIC UMR 995, F-59000, Lille, France
| | - Catherine Robbe-Masselot
- CNRS, Univ. Lille, UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle (UGSF), F-59000, Lille, France
| | - Frédéric Gottrand
- Inserm, Univ. Lille, CHU Lille, LIRIC UMR 995, F-59000, Lille, France
| | - Tetsuharu Narita
- CNRS, PSL Research University, UPMC Univ. Paris 06, ESPCI Paris, UMR 7615, Laboratoire Sciences et Ingénierie de la Matière Molle, 10 rue Vauquelin, 75231, Paris, Cedex 05, France.,Global Station for Soft Matter, Global Institution for Collaborative Research and Education, Hokkaido University, Sapporo, Japan
| | - Jean-Luc Desseyn
- Inserm, Univ. Lille, CHU Lille, LIRIC UMR 995, F-59000, Lille, France.
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8
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Ridley C, Lockhart-Cairns MP, Collins RF, Jowitt TA, Subramani DB, Kesimer M, Baldock C, Thornton DJ. The C-terminal dimerization domain of the respiratory mucin MUC5B functions in mucin stability and intracellular packaging before secretion. J Biol Chem 2019; 294:17105-17116. [PMID: 31570524 PMCID: PMC6851316 DOI: 10.1074/jbc.ra119.010771] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 09/20/2019] [Indexed: 12/19/2022] Open
Abstract
Mucin 5B (MUC5B) has an essential role in mucociliary clearance that protects the pulmonary airways. Accordingly, knowledge of MUC5B structure and its interactions with itself and other proteins is critical to better understand airway mucus biology and improve the management of lung diseases such as asthma, cystic fibrosis, and chronic obstructive pulmonary disease (COPD). The role of an N-terminal multimerization domain in the supramolecular organization of MUC5B has been previously described, but less is known about its C-terminal dimerization domain. Here, using cryogenic electron microscopy (cryo-EM) and small-angle X-ray scattering (SAXS) analyses of recombinant disulfide-linked dimeric MUC5B dimerization domain we identified an asymmetric, elongated twisted structure, with a double globular base. We found that the dimerization domain is more resistant to disruption than the multimerization domain suggesting the twisted structure of the dimerization domain confers additional stability to MUC5B polymers. Size-exclusion chromatography-multiangle light scattering (SEC-MALS), SPR-based biophysical analyses and microscale thermophoresis of the dimerization domain disclosed no further assembly, but did reveal reversible, calcium-dependent interactions between the dimerization and multimerization domains that were most active at acidic pH, suggesting that these domains have a role in MUC5B intragranular organization. In summary, our results suggest a role for the C-terminal dimerization domain of MUC5B in compaction of mucin chains during granular packaging via interactions with the N-terminal multimerization domain. Our findings further suggest that the less stable multimerization domain provides a potential target for mucin depolymerization to remove mucus plugs in COPD and other lung pathologies.
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Affiliation(s)
- Caroline Ridley
- Wellcome Trust Centre for Cell-Matrix Research, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom.,Division of Infection Immunity and Respiratory Medicine, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom.,School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom
| | - Michael P Lockhart-Cairns
- Wellcome Trust Centre for Cell-Matrix Research, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom.,School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom.,Division of Cell-Matrix Biology and Regenerative Medicine, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom
| | - Richard F Collins
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom
| | - Thomas A Jowitt
- Wellcome Trust Centre for Cell-Matrix Research, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom.,School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom
| | - Durai B Subramani
- Marsico Lung Institute/Cystic Fibrosis Research Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7362
| | - Mehmet Kesimer
- Marsico Lung Institute/Cystic Fibrosis Research Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7362
| | - Clair Baldock
- Wellcome Trust Centre for Cell-Matrix Research, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom .,School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom.,Division of Cell-Matrix Biology and Regenerative Medicine, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom
| | - David J Thornton
- Wellcome Trust Centre for Cell-Matrix Research, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom .,Division of Infection Immunity and Respiratory Medicine, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom.,School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom.,Lydia Becker Institute for Immunology and Inflammation, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom
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9
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Leung HM, Birket SE, Hyun C, Ford TN, Cui D, Solomon GM, Shei RJ, Adewale AT, Lenzie AR, Fernandez-Petty CM, Zheng H, Palermo JH, Cho DY, Woodworth BA, Yonker LM, Hurley BP, Rowe SM, Tearney GJ. Intranasal micro-optical coherence tomography imaging for cystic fibrosis studies. Sci Transl Med 2019; 11:eaav3505. [PMID: 31391319 PMCID: PMC6886258 DOI: 10.1126/scitranslmed.aav3505] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 07/09/2019] [Indexed: 12/11/2022]
Abstract
Cystic fibrosis (CF) is a genetic disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. Although impairment of mucociliary clearance contributes to severe morbidity and mortality in people with CF, a clear understanding of the pathophysiology is lacking. This is, in part, due to the absence of clinical imaging techniques capable of capturing CFTR-dependent functional metrics at the cellular level. Here, we report the clinical translation of a 1-μm resolution micro-optical coherence tomography (μOCT) technology to quantitatively characterize the functional microanatomy of human upper airways. Using a minimally invasive intranasal imaging approach, we performed a clinical study on age- and sex-matched CF and control groups. We observed delayed mucociliary transport rate at the cellular level, depletion of periciliary liquid layer, and prevalent loss of ciliation in subjects with CF. Distinctive morphological differences in mucus and various forms of epithelial injury were also revealed by μOCT imaging and had prominent effects on the mucociliary transport apparatus. Elevated mucus reflectance intensity in CF, a proxy for viscosity in situ, had a dominant effect. These results demonstrate the utility of μOCT to determine epithelial function and monitor disease status of CF airways on a per-patient basis, with applicability for other diseases of mucus clearance.
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Affiliation(s)
- Hui Min Leung
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Harvard Medical School, Boston, MA 02114, USA
| | - Susan E Birket
- Gregory Fleming James Cystic Fibrosis Research Center, Birmingham, AL 35294, USA
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Chulho Hyun
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Timothy N Ford
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Dongyao Cui
- Nanyang Technological University, Singapore 639798, Singapore
| | - George M Solomon
- Gregory Fleming James Cystic Fibrosis Research Center, Birmingham, AL 35294, USA
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Ren-Jay Shei
- Gregory Fleming James Cystic Fibrosis Research Center, Birmingham, AL 35294, USA
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | | | - Andrew R Lenzie
- Gregory Fleming James Cystic Fibrosis Research Center, Birmingham, AL 35294, USA
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Courtney M Fernandez-Petty
- Gregory Fleming James Cystic Fibrosis Research Center, Birmingham, AL 35294, USA
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Hui Zheng
- Harvard Medical School, Boston, MA 02114, USA
- Biostatistics Center, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Justin H Palermo
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Do-Yeon Cho
- Gregory Fleming James Cystic Fibrosis Research Center, Birmingham, AL 35294, USA
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Bradford A Woodworth
- Gregory Fleming James Cystic Fibrosis Research Center, Birmingham, AL 35294, USA
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Lael M Yonker
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Bryan P Hurley
- Mucosal Immunology and Biology Research Center, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Steven M Rowe
- Gregory Fleming James Cystic Fibrosis Research Center, Birmingham, AL 35294, USA.
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Guillermo J Tearney
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA.
- Harvard Medical School, Boston, MA 02114, USA
- Department of Pathology, Massachusetts General Hospital, Boston, MA 02114, USA
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10
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Fernandez-Petty CM, Hughes GW, Bowers HL, Watson JD, Rosen BH, Townsend SM, Santos C, Ridley CE, Chu KK, Birket SE, Li Y, Leung HM, Mazur M, Garcia BA, Evans TIA, Libby EF, Hathorne H, Hanes J, Tearney GJ, Clancy JP, Engelhardt JF, Swords WE, Thornton DJ, Wiesmann WP, Baker SM, Rowe SM. A glycopolymer improves vascoelasticity and mucociliary transport of abnormal cystic fibrosis mucus. JCI Insight 2019; 4:125954. [PMID: 30996141 DOI: 10.1172/jci.insight.125954] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 02/28/2019] [Indexed: 01/05/2023] Open
Abstract
Cystic fibrosis (CF) is characterized by increased mucus viscosity and delayed mucociliary clearance that contributes to progressive decline of lung function. Mucus in the respiratory and GI tract is excessively adhesive in the presence of airway dehydration and excess extracellular Ca2+ upon mucin release, promoting hyperviscous, densely packed mucins characteristic of CF. Therapies that target mucins directly through ionic interactions remain unexploited. Here we show that poly (acetyl, arginyl) glucosamine (PAAG), a polycationic biopolymer suitable for human use, interacts directly with mucins in a Ca2+-sensitive manner to reduce CF mucus viscoelasticity and improve its transport. Notably, PAAG induced a linear structure of purified MUC5B and altered its sedimentation profile and viscosity, indicative of proper mucin expansion. In vivo, PAAG nebulization improved mucociliary transport in CF rats with delayed mucus clearance, and cleared mucus plugging in CF ferrets. This study demonstrates the potential use of a synthetic glycopolymer PAAG as a molecular agent that could benefit patients with a broad array of mucus diseases.
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Affiliation(s)
| | - Gareth W Hughes
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, United Kingdom
| | - Hannah L Bowers
- Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, Alabama, USA
| | - John D Watson
- Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, Alabama, USA
| | - Bradley H Rosen
- Department of Anatomy & Cell Biology and.,Department of Medicine, University of Iowa, Iowa City, Iowa, USA
| | | | | | - Caroline E Ridley
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, United Kingdom
| | - Kengyeh K Chu
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, USA.,Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts, USA,Harvard Medical School, Boston, Massachusetts, USA.,Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, USA.,Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Susan E. Birket
- Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, Alabama, USA.,Gregory Fleming James Cystic Fibrosis Research Center
| | - Yao Li
- Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, Alabama, USA.,Gregory Fleming James Cystic Fibrosis Research Center
| | - Hui Min Leung
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, USA.,Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts, USA,Harvard Medical School, Boston, Massachusetts, USA.,Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, USA.,Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Marina Mazur
- Gregory Fleming James Cystic Fibrosis Research Center
| | - Bryan A Garcia
- Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, Alabama, USA.,Gregory Fleming James Cystic Fibrosis Research Center
| | | | | | - Heather Hathorne
- Gregory Fleming James Cystic Fibrosis Research Center,Department of Pediatrics, UAB, Birmingham, Alabama, USA
| | - Justin Hanes
- Center for Nanomedicine and Departments of Biomedical Engineering, Chemical & Biomolecular Sciences, Johns Hopkins University, Baltimore, Maryland, USA
| | - Guillermo J Tearney
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, Massachusetts, USA.,Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts, USA,Harvard Medical School, Boston, Massachusetts, USA.,Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, USA.,Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - John P Clancy
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - John F Engelhardt
- Department of Anatomy & Cell Biology and.,Department of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - William E Swords
- Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, Alabama, USA.,Gregory Fleming James Cystic Fibrosis Research Center
| | - David J Thornton
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, United Kingdom
| | | | | | - Steven M Rowe
- Department of Medicine, University of Alabama at Birmingham (UAB), Birmingham, Alabama, USA.,Gregory Fleming James Cystic Fibrosis Research Center,Department of Pediatrics, UAB, Birmingham, Alabama, USA.,Department of Cell Developmental & Integrative Biology, UAB, Birmingham, Alabama, USA
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11
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Mucins: the frontline defence of the lung. Biochem Soc Trans 2018; 46:1099-1106. [PMID: 30154090 PMCID: PMC6195635 DOI: 10.1042/bst20170402] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/17/2018] [Accepted: 07/18/2018] [Indexed: 02/07/2023]
Abstract
Mucus plays a vital role in protecting the lungs from environmental factors, but conversely, in muco-obstructive airway disease, mucus becomes pathologic. In its protective role, mucus entraps microbes and particles removing them from the lungs via the co-ordinated beating of motile cilia. This mechanism of lung defence is reliant upon a flowing mucus gel, and the major macromolecular components that determine the rheological properties of mucus are the polymeric mucins, MUC5AC and MUC5B. These large O-linked glycoproteins have direct roles in maintaining lung homeostasis. MUC5B is essential for interaction with the ciliary clearance system and MUC5AC is up-regulated in response to allergic inflammatory challenge. Mucus with abnormal biophysical properties is a feature of muco-obstructive respiratory disease and can result from many different mechanisms including alterations in mucin polymer assembly, mucin concentration and the macromolecular form in mucus, as well as changes in airway surface hydration, pH and ion composition. The abnormal mucus results in defective lung protection via compromised ciliary clearance, leading to infection and inflammation.
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12
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Role of mucins in lung homeostasis: regulated expression and biosynthesis in health and disease. Biochem Soc Trans 2018; 46:707-719. [PMID: 29802217 DOI: 10.1042/bst20170455] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 04/24/2018] [Accepted: 04/26/2018] [Indexed: 01/02/2023]
Abstract
In humans and mice, the first line of innate defense against inhaled pathogens and particles in the respiratory tract is airway mucus. The primary solid components of the mucus layer are the mucins MUC5AC and MUC5B, polymeric glycoproteins whose changes in abundance and structure can dramatically affect airway defense. Accordingly, MUC5AC/Muc5ac and MUC5B/Muc5b are tightly regulated at a transcriptional level by tissue-specific transcription factors in homeostasis and in response to injurious and inflammatory triggers. In addition to modulated levels of mucin gene transcription, translational and post-translational biosynthetic processes also exert significant influence upon mucin function. Mucins are massive macromolecules with numerous functional domains that contribute to their structural composition and biophysical properties. Single MUC5AC and MUC5B apoproteins have molecular masses of >400 kDa, and von Willebrand factor D-like as well as other cysteine-rich domain segments contribute to mucin polymerization and flexibility, thus increasing apoprotein length and complexity. Additional domains serve as sites for O-glycosylation, which increase further mucin mass several-fold. Glycosylation is a defining process for mucins that is specific with respect to additions of glycans to mucin apoprotein backbones, and glycan additions influence the physical properties of the mucins via structural modifications as well as charge interactions. Ultimately, through their tight regulation and complex assembly, airway mucins follow the biological rule of 'form fits function' in that their structural organization influences their role in lung homeostatic mechanisms.
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Functional characterization of the mucus barrier on the Xenopus tropicalis skin surface. Proc Natl Acad Sci U S A 2018; 115:726-731. [PMID: 29311327 PMCID: PMC5789918 DOI: 10.1073/pnas.1713539115] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The production of mucus helps to trap pathogens, preventing their entry into the body, while it also acts as an interface for many important physiological events (e.g., gas and nutrient exchange). In mammalian models, a detailed study of mucus and its component parts is hindered by the difficulty in accessing these internally located tissues. The Xenopus tropicalis tadpole skin offers a complementary nonmammalian model system to study mucosal epithelia. Using this, we identify a mucin, similar to human mucins, that protects against infection. This system offers an experimentally tractable approach to study mucins and the mucus barrier and their role in conferring protection at mucosal surfaces. Mucosal surfaces represent critical routes for entry and exit of pathogens. As such, animals have evolved strategies to combat infection at these sites, in particular the production of mucus to prevent attachment and to promote subsequent movement of the mucus/microbe away from the underlying epithelial surface. Using biochemical, biophysical, and infection studies, we have investigated the host protective properties of the skin mucus barrier of the Xenopus tropicalis tadpole. Specifically, we have characterized the major structural component of the barrier and shown that it is a mucin glycoprotein (Otogelin-like or Otogl) with similar sequence, domain organization, and structural properties to human gel-forming mucins. This mucin forms the structural basis of a surface barrier (∼6 μm thick), which is depleted through knockdown of Otogl. Crucially, Otogl knockdown leads to susceptibility to infection by the opportunistic pathogen Aeromonas hydrophila. To more accurately reflect its structure, tissue localization, and function, we have renamed Otogl as Xenopus Skin Mucin, or MucXS. Our findings characterize an accessible and tractable model system to define mucus barrier function and host–microbe interactions.
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Mucins, Mucus, and Goblet Cells. Chest 2017; 154:169-176. [PMID: 29170036 DOI: 10.1016/j.chest.2017.11.008] [Citation(s) in RCA: 228] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 10/19/2017] [Accepted: 11/06/2017] [Indexed: 12/12/2022] Open
Abstract
The respiratory epithelium is lined by mucus, a gel consisting of water, ions, proteins, and macromolecules. The major macromolecular components of mucus are the mucin glycoproteins, which are critical for local defense of the airway. There are three classes of mucins in the airways: those that are secreted but do not polymerize (MUC7), those that are secreted and polymerize to form gels (MUC5AC, MUC5B), and those that have transmembrane domains and are cell surface associated (MUC1, MUC4, MUC16, MUC20). The mucins are regulated at the transcriptional, posttranscriptional, and epigenetic levels, and posttranslational modifications play an important role in mucin binding and clearance of microbes and pollutants. The development of mice deficient in specific mucins, and the cystic fibrosis pig, has greatly advanced our understanding of the role of mucins as innate immune mediators and how mucins and mucus contribute to lung disease. These observations suggest new strategies to ameliorate mucus obstruction by targeting mucociliary clearance and mucin hyperconcentration. Furthermore, a polymorphism in the promoter of MUC5B is strongly associated with risk of developing pulmonary fibrosis, supporting a novel function for MUC5B to influence interstitial lung disease. Exciting new data support the concept not only that mucins and mucus are important for lung homeostasis and protection from environmental threats but also that goblet cells play an important role as regulators of innate immune function. These insights into the innate immune properties of mucins and goblet cells support a shift from the current paradigm of repressing increased mucin expression to targeting regulation of specific mucins and the abnormal airway milieu.
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Menou A, Duitman J, Flajolet P, Sallenave JM, Mailleux AA, Crestani B. Human airway trypsin-like protease, a serine protease involved in respiratory diseases. Am J Physiol Lung Cell Mol Physiol 2017; 312:L657-L668. [DOI: 10.1152/ajplung.00509.2016] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 02/15/2017] [Accepted: 02/15/2017] [Indexed: 01/12/2023] Open
Abstract
More than 2% of all human genes are coding for a complex system of more than 700 proteases and protease inhibitors. Among them, serine proteases play extraordinary, diverse functions in different physiological and pathological processes. The human airway trypsin-like protease (HAT), also referred to as TMPRSS11D and serine 11D, belongs to the emerging family of cell surface proteolytic enzymes, the type II transmembrane serine proteases (TTSPs). Through the cleavage of its four major identified substrates, HAT triggers specific responses, notably in epithelial cells, within the pericellular and extracellular environment, including notably inflammatory cytokine production, inflammatory cell recruitment, or anticoagulant processes. This review summarizes the potential role of this recently described protease in mediating cell surface proteolytic events, to highlight the structural features, proteolytic activity, and regulation, including the expression profile of HAT, and discuss its possible roles in respiratory physiology and disease.
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Affiliation(s)
- Awen Menou
- Inserm UMR1152, Medical School Xavier Bichat, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Département Hospitalo-Universitaire FIRE (Fibrosis, Inflammation and Remodeling) and LabEx Inflamex, Paris, France; and
| | - JanWillem Duitman
- Inserm UMR1152, Medical School Xavier Bichat, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Département Hospitalo-Universitaire FIRE (Fibrosis, Inflammation and Remodeling) and LabEx Inflamex, Paris, France; and
| | - Pauline Flajolet
- Inserm UMR1152, Medical School Xavier Bichat, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Département Hospitalo-Universitaire FIRE (Fibrosis, Inflammation and Remodeling) and LabEx Inflamex, Paris, France; and
| | - Jean-Michel Sallenave
- Inserm UMR1152, Medical School Xavier Bichat, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Département Hospitalo-Universitaire FIRE (Fibrosis, Inflammation and Remodeling) and LabEx Inflamex, Paris, France; and
| | - Arnaud André Mailleux
- Inserm UMR1152, Medical School Xavier Bichat, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Département Hospitalo-Universitaire FIRE (Fibrosis, Inflammation and Remodeling) and LabEx Inflamex, Paris, France; and
| | - Bruno Crestani
- Inserm UMR1152, Medical School Xavier Bichat, Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Département Hospitalo-Universitaire FIRE (Fibrosis, Inflammation and Remodeling) and LabEx Inflamex, Paris, France; and
- APHP, Hôpital Bichat, Service de Pneumologie A, Paris, France
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