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Abstract
The mucosal surfaces that form the boundary between the external environment and the underlying tissue are protected by a mucus barrier. Mucin glycoproteins, both secreted and cell surface mucins, are the major components of the barrier. They can exclude pathogens and toxins while hosting the commensal bacteria. In this review, we highlight the dynamic function of the mucins and mucus during infection, how this mucosal barrier is regulated, and how pathogens have evolved mechanisms to evade this defence system.
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Affiliation(s)
- Yong Hua Sheng
- Immunopathology Group, Mater Research Institute−The University of Queensland, Translational Research Institute, Brisbane, Qld, Australia
| | - Sumaira Z. Hasnain
- Immunopathology Group, Mater Research Institute−The University of Queensland, Translational Research Institute, Brisbane, Qld, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Qld, Australia
- *Correspondence: Sumaira Z. Hasnain,
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Iverson E, Griswold K, Song D, Gagliardi TB, Hamidzadeh K, Kesimer M, Sinha S, Perry M, Duncan GA, Scull MA. Membrane-Tethered Mucin 1 Is Stimulated by Interferon and Virus Infection in Multiple Cell Types and Inhibits Influenza A Virus Infection in Human Airway Epithelium. mBio 2022;:e0105522. [PMID: 35699372 DOI: 10.1128/mbio.01055-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Influenza A virus (IAV) causes significant morbidity and mortality in the human population. Tethered mucin 1 (MUC1) is highly expressed in airway epithelium, the primary site of IAV replication, and also by other cell types that influence IAV infection, including macrophages. MUC1 has the potential to influence infection dynamics through physical interactions and/or signaling activity, yet MUC1 modulation and its impact during viral pathogenesis remain unclear. Thus, we investigated MUC1-IAV interactions in an in vitro model of human airway epithelium (HAE). Our data indicate that a recombinant IAV hemagglutinin (H3) and H3N2 virus can bind endogenous HAE MUC1. Notably, infection of HAE with H1N1 or H3N2 IAV strains does not trigger MUC1 shedding but instead stimulates an increase in cell-associated MUC1 protein. We observed a similar increase after type I or III interferon (IFN) stimulation; however, inhibition of IFN signaling during H1N1 infection only partially abrogated this increase, indicating that multiple soluble factors contribute to MUC1 upregulation during the antiviral response. In addition to HAE, primary human monocyte-derived macrophages also upregulated MUC1 protein in response to IFN treatment and conditioned media from IAV-infected HAE. Then, to determine the impact of MUC1 on IAV pathogenesis, we developed HAE genetically depleted of MUC1 and found that MUC1 knockout cultures exhibited enhanced viral growth compared to control cultures for several IAV strains. Together, our data support a model whereby MUC1 inhibits productive uptake of IAV in HAE. Infection then stimulates MUC1 expression on multiple cell types through IFN-dependent and -independent mechanisms that further impact infection dynamics.
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3
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Abstract
Mammalian neuraminidases (NEUs), also known as sialidases, are enzymes that cleave off the terminal neuraminic, or sialic, acid resides from the carbohydrate moieties of glycolipids and glycoproteins. A rapidly growing body of literature indicates that in addition to their metabolic functions, NEUs also regulate the activity of their glycoprotein targets. The simple post-translational modification of NEU protein targets-removal of the highly electronegative sialic acid-affects protein folding, alters protein interactions with their ligands, and exposes or covers proteolytic sites. Through such effects, NEUs regulate the downstream processes in which their glycoprotein targets participate. A major target of desialylation by NEUs are mucins (MUCs), and such post-translational modification contributes to regulation of disease processes. In this review, we focus on the regulatory roles of NEU-modified MUCs as coordinators of disease pathogenesis in fibrotic, inflammatory, infectious, and autoimmune diseases. Special attention is placed on the most abundant and best studied NEU1, and its recently discovered important target, mucin-1 (MUC1). The role of the NEU1 - MUC1 axis in disease pathogenesis is discussed, along with regulatory contributions from other MUCs and other pathophysiologically important NEU targets.
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Affiliation(s)
- Erik P. Lillehoj
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Irina G. Luzina
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
- Research Service, Baltimore Veterans Affairs (VA) Medical Center, Baltimore, MD, United States
| | - Sergei P. Atamas
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
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Kennel C, Gould EA, Larson ED, Salcedo E, Vickery T, Restrepo D, Ramakrishnan VR. Differential Expression of Mucins in Murine Olfactory Versus Respiratory Epithelium. Chem Senses 2020; 44:511-521. [PMID: 31300812 DOI: 10.1093/chemse/bjz046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Mucins are a key component of the surface mucus overlying airway epithelium. Given the different functions of the olfactory and respiratory epithelia, we hypothesized that mucins would be differentially expressed between these 2 areas. Secondarily, we evaluated for potential changes in mucin expression with radiation exposure, given the clinical observations of nasal dryness, altered mucus rheology, and smell loss in radiated patients. Immunofluorescence staining was performed to evaluate expression of mucins 1, 2, 5AC, and 5B in nasal respiratory and olfactory epithelia of control mice and 1 week after exposure to 8 Gy of radiation. Mucins 1, 5AC, and 5B exhibited differential expression patterns between olfactory and respiratory epithelium (RE) while mucin 2 showed no difference. In the olfactory epithelium (OE), mucin 1 was located in a lattice-like pattern around gaps corresponding to dendritic knobs of olfactory sensory neurons, whereas in RE it was intermittently expressed by surface goblet cells. Mucin 5AC was expressed by subepithelial glands in both epithelial types but to a higher degree in the OE. Mucin 5B was expressed by submucosal glands in OE and by surface epithelial cells in RE. At 1-week after exposure to single-dose 8 Gy of radiation, no qualitative effects were seen on mucin expression. Our findings demonstrate that murine OE and RE express mucins differently, and characteristic patterns of mucins 1, 5AC, and 5B can be used to define the underlying epithelium. Radiation (8 Gy) does not appear to affect mucin expression at 1 week. LEVEL OF EVIDENCE N/A (Basic Science Research).IACUC-approved study [Protocol 200065].
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Affiliation(s)
- Christopher Kennel
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Elizabeth A Gould
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA.,Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine, Aurora, CO, USA.,Neuroscience Program, University of Colorado School of Medicine, Aurora, CO, USA
| | - Eric D Larson
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Ernesto Salcedo
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Thad Vickery
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Diego Restrepo
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA.,Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine, Aurora, CO, USA.,Neuroscience Program, University of Colorado School of Medicine, Aurora, CO, USA
| | - Vijay R Ramakrishnan
- Department of Otolaryngology, University of Colorado School of Medicine, Aurora, CO, USA.,Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine, Aurora, CO, USA.,Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO, USA
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McAuley JL, Corcilius L, Tan HX, Payne RJ, McGuckin MA, Brown LE. The cell surface mucin MUC1 limits the severity of influenza A virus infection. Mucosal Immunol 2017; 10:1581-93. [PMID: 28327617 DOI: 10.1038/mi.2017.16] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 01/26/2017] [Indexed: 02/04/2023]
Abstract
Cell surface mucin (cs-mucin) glycoproteins are constitutively expressed at the surface of respiratory epithelia where pathogens such as influenza A virus (IAV) gain entry into cells. Different members of the cs-mucin family each express a large and heavily glycosylated extracellular domain that towers above other receptors on the epithelial cell surface, a transmembrane domain that enables shedding of the extracellular domain, and a cytoplasmic tail capable of triggering signaling cascades. We hypothesized that IAV can interact with the terminal sialic acids presented on the extracellular domain of cs-mucins, resulting in modulation of infection efficiency. Utilizing human lung epithelial cells, we found that IAV associates with the cs-mucin MUC1 but not MUC13 or MUC16. Overexpression of MUC1 by epithelial cells or the addition of sialylated synthetic MUC1 constructs, reduced IAV infection in vitro. In addition, Muc1-/- mice infected with IAV exhibited enhanced morbidity and mortality, as well as greater inflammatory mediator responses compared to wild type mice. This study implicates the cs-mucin MUC1 as a critical and dynamic component of the innate host response that limits the severity of influenza and provides the foundation for exploration of MUC1 in resolving inflammatory disease.
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McCarthy MK, Procario MC, Wilke CA, Moore BB, Weinberg JB. Prostaglandin E2 Production and T Cell Function in Mouse Adenovirus Type 1 Infection following Allogeneic Bone Marrow Transplantation. PLoS One 2015; 10:e0139235. [PMID: 26407316 DOI: 10.1371/journal.pone.0139235] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 09/10/2015] [Indexed: 11/19/2022] Open
Abstract
Adenovirus infections are important complications of bone marrow transplantation (BMT). We demonstrate delayed clearance of mouse adenovirus type 1 (MAV-1) from lungs of mice following allogeneic BMT. Virus-induced prostaglandin E2 (PGE2) production was greater in BMT mice than in untransplanted controls, but BMT using PGE2-deficient donors or recipients failed to improve viral clearance, and treatment of untransplanted mice with the PGE2 analog misoprostol did not affect virus clearance. Lymphocyte recruitment to the lungs was not significantly affected by BMT. Intracellular cytokine staining of lung lymphocytes demonstrated impaired production of INF-γ and granzyme B by cells from BMT mice, and production of IFN-γ, IL-2, IL-4, and IL-17 following ex vivo stimulation was impaired in lymphocytes obtained from lungs of BMT mice. Viral clearance was not delayed in untransplanted INF-γ-deficient mice, suggesting that delayed viral clearance in BMT mice was not a direct consequence of impaired IFN-γ production. However, lung viral loads were higher in untransplanted CD8-deficient mice than in controls, suggesting that delayed MAV-1 clearance in BMT mice is due to defective CD8 T cell function. We did not detect significant induction of IFN-β expression in lungs of BMT mice or untransplanted controls, and viral clearance was not delayed in untransplanted type I IFN-unresponsive mice. We conclude that PGE2 overproduction in BMT mice is not directly responsible for delayed viral clearance. PGE2-independent effects on CD8 T cell function likely contribute to the inability of BMT mice to clear MAV-1 from the lungs.
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Apostolopoulos V, Stojanovska L, Gargosky SE. MUC1 (CD227): a multi-tasked molecule. Cell Mol Life Sci 2015; 72:4475-500. [DOI: 10.1007/s00018-015-2014-z] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 07/23/2015] [Accepted: 08/06/2015] [Indexed: 12/16/2022]
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McCarthy MK, Levine RE, Procario MC, McDonnell PJ, Zhu L, Mancuso P, Crofford LJ, Aronoff DM, Weinberg JB. Prostaglandin E2 induction during mouse adenovirus type 1 respiratory infection regulates inflammatory mediator generation but does not affect viral pathogenesis. PLoS One 2013; 8:e77628. [PMID: 24147040 PMCID: PMC3797793 DOI: 10.1371/journal.pone.0077628] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 09/03/2013] [Indexed: 01/13/2023] Open
Abstract
Respiratory viruses cause substantial disease and are a significant healthcare burden. Virus-induced inflammation can be detrimental to the host, causing symptoms during acute infection and leading to damage that contributes to long-term residual lung disease. Prostaglandin E2 (PGE2) is a lipid mediator that is increased in response to many viral infections, and inhibition of PGE2 production during respiratory viral infection often leads to a decreased inflammatory response. We tested the hypothesis that PGE2 promotes inflammatory responses to mouse adenovirus type 1 (MAV-1) respiratory infection. Acute MAV-1 infection increased COX-2 expression and PGE2 production in wild type mice. Deficiency of the E prostanoid 2 receptor had no apparent effect on MAV-1 pathogenesis. Virus-induced induction of PGE2, IFN-γ, CXCL1, and CCL5 was reduced in mice deficient in microsomal PGE synthase-1 (mPGES-1-/- mice). However, there were no differences between mPGES-1+/+ and mPGES-1-/- mice in viral replication, recruitment of leukocytes to airways or lung inflammation. Infection of both mPGES‑1+/+ and mPGES-1-/- mice led to protection against reinfection. Thus, while PGE2 promotes the expression of a variety of cytokines in response to acute MAV-1 infection, PGE2 synthesis does not appear to be essential for generating pulmonary immunity.
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Affiliation(s)
- Mary K. McCarthy
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Rachael E. Levine
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Megan C. Procario
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Peter J. McDonnell
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Lingqiao Zhu
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Peter Mancuso
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Leslie J. Crofford
- Department of Internal Medicine, Vanderbilt University, Nashville, Tennessee, United States of America
| | - David M. Aronoff
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Jason B. Weinberg
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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Abstract
Tripartite motif-containing 21 (TRIM21) is a cytosolic immunoglobulin receptor that mediates antibody-dependent intracellular neutralization (ADIN). Here we show that TRIM21 potently inhibits the spreading infection of a replicating cytopathic virus and activates innate immunity. We used a quantitative PCR (qPCR)-based assay to measure in vitro replication of mouse adenovirus type 1 (MAV-1), a virus that causes dose-dependent hemorrhagic encephalitis in mice. Using this assay, we show that genetic ablation of TRIM21 or chemical inhibition of either the AAA ATPase p97/valosin-containing protein (VCP) or the proteasome results in a >1,000-fold increase in the relative level of infection in the presence of immune serum. Moreover, the TRIM21-mediated ability of antisera to block replication was a consistent feature of the humoral immune response in immunized mice. In the presence of immune sera and upon infection, TRIM21 also activates a proinflammatory response, resulting in secretion of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6). These results demonstrate that TRIM21 provides a potent block to spreading infection and induces an antiviral state.
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Woodward AM, Mauris J, Argüeso P. Binding of transmembrane mucins to galectin-3 limits herpesvirus 1 infection of human corneal keratinocytes. J Virol 2013; 87:5841-7. [PMID: 23487460 DOI: 10.1128/JVI.00166-13] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Epithelial cells lining mucosal surfaces impose multiple barriers to viral infection. At the ocular surface, the carbohydrate-binding protein galectin-3 maintains barrier function by cross-linking transmembrane mucins on the apical glycocalyx. Despite these defense mechanisms, many viruses have evolved to exploit fundamental cellular processes on host cells. Here, we use affinity assays to show that herpes simplex virus type 1 (HSV-1), but not HSV-2, binds human galectin-3. Knockdown of galectin-3 in human corneal keratinocytes by small interfering RNA significantly impaired HSV-1 infection, but not expression of nectin-1, indicating that galectin-3 is a herpesvirus entry mediator. Interestingly, exposure of epithelial cell cultures to transmembrane mucin isolates decreased viral infectivity. Moreover, HSV-1 failed to elute the biological counterreceptor MUC16 from galectin-3 affinity columns, suggesting that association of transmembrane mucins to galectin-3 provides protection against viral infection. Together, these results indicate that HSV-1 exploits galectin-3 to enhance virus attachment to host cells and support a protective role for transmembrane mucins under physiological conditions by masking viral entry mediators on the epithelial glycocalyx.
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Procario MC, Levine RE, McCarthy MK, Kim E, Zhu L, Chang CH, Hershenson MB, Weinberg JB. Susceptibility to acute mouse adenovirus type 1 respiratory infection and establishment of protective immunity in neonatal mice. J Virol 2012; 86:4194-203. [PMID: 22345470 DOI: 10.1128/JVI.06967-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
There is an incomplete understanding of the differences between neonatal immune responses that contribute to the increased susceptibility of neonates to some viral infections. We tested the hypothesis that neonates are more susceptible than adults to mouse adenovirus type 1 (MAV-1) respiratory infection and are impaired in the ability to generate a protective immune response against a second infection. Following intranasal infection, lung viral loads were greater in neonates than in adults during the acute phase but the virus was cleared from the lungs of neonates as efficiently as it was from adult lungs. Lung gamma interferon (IFN-γ) responses were blunted and delayed in neonates, and lung viral loads were higher in adult IFN-γ(-/-) mice than in IFN-γ(+/+) controls. However, administration of recombinant IFN-γ to neonates had no effect on lung viral loads. Recruitment of inflammatory cells to the airways was impaired in neonates. CD4 and CD8 T cell responses were similar in the lungs of neonates and adults, although a transient increase in regulatory T cells occurred only in the lungs of infected neonates. Infection of neonates led to protection against reinfection later in life that was associated with increased effector memory CD8 T cells in the lungs. We conclude that neonates are more susceptible than adults to acute MAV-1 respiratory infection but are capable of generating protective immune responses.
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