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Influenza A Virus M2 Protein: Roles from Ingress to Egress. Int J Mol Sci 2017; 18:ijms18122649. [PMID: 29215568 PMCID: PMC5751251 DOI: 10.3390/ijms18122649] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 12/04/2017] [Accepted: 12/05/2017] [Indexed: 11/17/2022] Open
Abstract
Influenza A virus (IAV) matrix protein 2 (M2) is among the smallest bona fide, hence extensively studied, ion channel proteins. The M2 ion channel activity is not only essential for virus replication, but also involved in modulation of cellular homeostasis in a variety of ways. It is also the target for ion channel inhibitors, i.e., anti-influenza drugs. Thus far, several studies have been conducted to elucidate its biophysical characteristics, structure-function relationships of the ion channel, and the M2-host interactome. In this review, we discuss M2 protein synthesis and assembly into an ion channel, its roles in IAV replication, and the pathophysiological impact on the host cell.
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Bartoszewski R, Matalon S, Collawn JF. Ion channels of the lung and their role in disease pathogenesis. Am J Physiol Lung Cell Mol Physiol 2017; 313:L859-L872. [PMID: 29025712 PMCID: PMC5792182 DOI: 10.1152/ajplung.00285.2017] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 10/03/2017] [Accepted: 10/03/2017] [Indexed: 12/16/2022] Open
Abstract
Maintenance of normal epithelial ion and water transport in the lungs includes providing a thin layer of surface liquid that coats the conducting airways. This airway surface liquid is critical for normal lung function in a number of ways but, perhaps most importantly, is required for normal mucociliary clearance and bacterial removal. Preservation of the appropriate level of hydration, pH, and viscosity for the airway surface liquid requires the proper regulation and function of a battery of different types of ion channels and transporters. Here we discuss how alterations in ion channel/transporter function often lead to lung pathologies.
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Affiliation(s)
- Rafal Bartoszewski
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Gdansk, Poland
| | - Sadis Matalon
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
- Department of Cell, Developmental, and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
- Pulmonary Injury and Repair Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
- Gregory Fleming James Cystic Fibrosis Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - James F Collawn
- Department of Cell, Developmental, and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama;
- Pulmonary Injury and Repair Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
- Gregory Fleming James Cystic Fibrosis Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
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Matalon S, Bartoszewski R, Collawn JF. Role of epithelial sodium channels in the regulation of lung fluid homeostasis. Am J Physiol Lung Cell Mol Physiol 2015; 309:L1229-38. [PMID: 26432872 DOI: 10.1152/ajplung.00319.2015] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 09/25/2015] [Indexed: 01/11/2023] Open
Abstract
In utero, fetal lung epithelial cells actively secrete Cl(-) ions into the lung air spaces while Na(+) ions follow passively to maintain electroneutrality. This process, driven by an electrochemical gradient generated by the Na(+)-K(+)-ATPase, is responsible for the secretion of fetal fluid that is essential for normal lung development. Shortly before birth, a significant upregulation of amiloride-sensitive epithelial channels (ENaCs) on the apical side of the lung epithelial cells results in upregulation of active Na(+) transport. This process is critical for the reabsorption of fetal lung fluid and the establishment of optimum gas exchange. In the adult lung, active Na(+) reabsorption across distal lung epithelial cells limits the degree of alveolar edema in patients with acute lung injury and cardiogenic edema. Cl(-) ions are transported either paracellularly or transcellularly to preserve electroneutrality. An increase in Cl(-) secretion across the distal lung epithelium has been reported following an acute increase in left atrial pressure and may result in pulmonary edema. In contrast, airway epithelial cells secrete Cl(-) through apical cystic fibrosis transmembrane conductance regulator and Ca(2+)-activated Cl(-) channels and absorb Na(+). Thus the coordinated action of Cl(-) secretion and Na(+) absorption is essential for maintenance of the volume of epithelial lining fluid that, in turn, maximizes mucociliary clearance and facilitates clearance of bacteria and debris from the lungs. Any factor that interferes with Na(+) or Cl(-) transport or dramatically upregulates ENaC activity in airway epithelial cells has been associated with lung diseases such as cystic fibrosis or chronic obstructive lung disease. In this review we focus on the role of the ENaC, the mechanisms involved in ENaC regulation, and how ENaC dysregulation can lead to lung pathology.
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Affiliation(s)
- Sadis Matalon
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Department of Cell, Developmental, and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Pulmonary Injury and Repair Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Gregory Fleming James Cystic Fibrosis Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - Rafal Bartoszewski
- Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Gdansk, Poland
| | - James F Collawn
- Department of Cell, Developmental, and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Pulmonary Injury and Repair Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Gregory Fleming James Cystic Fibrosis Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
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Gregory DJ, Kobzik L. Influenza lung injury: mechanisms and therapeutic opportunities. Am J Physiol Lung Cell Mol Physiol 2015; 309:L1041-6. [PMID: 26408556 DOI: 10.1152/ajplung.00283.2015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 09/16/2015] [Indexed: 12/22/2022] Open
Abstract
In this Perspectives, we discuss some recent developments in the pathogenesis of acute lung injury following influenza infection, with an emphasis on promising therapeutic leads. Damage to the alveolar-capillary barrier has been quantified in mice, and agents have been identified that can help to preserve barrier integrity, such as vasculotide, angiopoietin-like 4 neutralization, and sphingosine 1-phosphate mimics. Results from studies using mesenchymal stem cells have been disappointing, despite promising data in other types of lung injury. The roles of fatty acid binding protein 5, prostaglandin E2, and the interplay between IFN-γ and STAT1 in epithelial signaling during infection have been addressed in vitro. Finally, we discuss the role of autophagy in inflammatory cytokine production and the viral life cycle and the opportunities this presents for intervention.
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Affiliation(s)
- David J Gregory
- Molecular and Integrative Physiological Sciences Program, Department of Environmental Health, Harvard T. H. Chan School of Public Health
| | - Lester Kobzik
- Molecular and Integrative Physiological Sciences Program, Department of Environmental Health, Harvard T. H. Chan School of Public Health
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Matalon S. A critical review of the American Journal of Physiology-Lung Cellular and Molecular Physiology: 2012-2015. Am J Physiol Lung Cell Mol Physiol 2014; 307:L911-6. [PMID: 25381028 DOI: 10.1152/ajplung.00330.2014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
I have had the privilege of serving as Editor-in-Chief of the American Journal of Physiology: Lung Cellular and Molecular Physiology from 1/1/2012 to 1/1/2015 and have been reappointed for another 3-year term. When I took over as editor, I published an editorial in AJP-Lung in which I highlighted my vision and outlined the tasks to be accomplished to transform AJP-Lung into "The best place to publish basic, translational, and hypothesis-driven clinical lung research." Herein I review our accomplishments during the first term. As promised, we review each article submitted to this journal and our reviews always help the quality and impact of every paper. We recognized the contributions of junior authors by establishing a number of awards and increased the visibility of AJP-Lung by establishing Facebook and Blog electronic pages and sponsoring symposia in scientific meetings. Our impact factor increased from 3.523 in 2011 to 4.041 in 2012 and, thanks to our calls for papers, we are receiving large numbers of high-quality papers in all aspects of pulmonary cell biology and lung diseases. The best is yet to come.
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Affiliation(s)
- Sadis Matalon
- Department of Anesthesiology and Pulmonary Injury and Repair Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
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Abstract
CFTR is a cAMP-activated chloride and bicarbonate channel that is critical for lung homeostasis. Decreases in CFTR expression have dire consequences in cystic fibrosis (CF) and have been suggested to be a component of the lung pathology in chronic obstructive pulmonary disease. Decreases or loss of channel function often lead to mucus stasis, chronic bacterial infections, and the accompanying chronic inflammatory responses that promote progressive lung destruction, and, eventually in CF, lung failure. Here we discuss CFTR's functional role airway surface liquid hydration and pH, in regulation of other channels such as the epithelial sodium channel, and in regulating inflammatory responses in the lung.
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Affiliation(s)
- James F Collawn
- Department of Cell, Developmental and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Pulmonary Injury and Repair Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and Gregory Fleming James Cystic Fibrosis Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
| | - Sadis Matalon
- Department of Anesthesiology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Department of Cell, Developmental and Integrative Biology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; Pulmonary Injury and Repair Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and Gregory Fleming James Cystic Fibrosis Center, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama
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