title: Pulmonary epithelial barrier function: some new players and mechanisms.
abstract: The pulmonary epithelium serves as a barrier to prevent access of the inspired luminal contents to the subepithelium. In addition, the epithelium dictates the initial responses of the lung to both infectious and noninfectious stimuli. One mechanism by which the epithelium does this is by coordinating transport of diffusible molecules across the epithelial barrier, both through the cell and between cells. In this review, we will discuss a few emerging paradigms of permeability changes through altered ion transport and paracellular regulation by which the epithelium gates its response to potentially detrimental luminal stimuli. This review is a summary of talks presented during a symposium in Experimental Biology geared toward novel and less recognized methods of epithelial barrier regulation. First, we will discuss mechanisms of dynamic regulation of cell-cell contacts in the context of repetitive exposure to inhaled infectious and noninfectious insults. In the second section, we will briefly discuss mechanisms of transcellular ion homeostasis specifically focused on the role of claudins and paracellular ion-channel regulation in chronic barrier dysfunction. In the next section, we will address transcellular ion transport and highlight the role of Trek-1 in epithelial responses to lung injury. In the final section, we will outline the role of epithelial growth receptor in barrier regulation in baseline, acute lung injury, and airway disease. We will then end with a summary of mechanisms of epithelial control as well as discuss emerging paradigms of the epithelium role in shifting between a structural element that maintains tight cell-cell adhesion to a cell that initiates and participates in immune responses.
authors: Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland;
authors: Kieran
authors: K
authors: Brune
authors: The Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, San Francisco VA Medical Center, and NCIRE/Veterans Health Research Institute, San Francisco, California;
authors: James
authors: J
authors: Frank
authors: Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee;
authors: Andreas
authors: A
authors: Schwingshackl
authors: Division of Oncology, Cancer Center, National Jewish Health, Denver, Colorado.
authors: James
authors: J
authors: Finigan
authors: Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland; vsidhay1@jhmi.edu.
authors: Venkataramana K
authors: VK
authors: Sidhaye
mesh_terms: D000818:Animals; D001692:Biological Transport; D004848:Epithelium / Q000502:physiology; D006801:Humans; D008168:Lung / Q000166:cytology / Q000502:physiology; D010539:Permeability; D011650:Pulmonary Alveoli / Q000166:cytology / Q000502:physiology; D020545:Respiratory Mucosa / Q000502:physiology*; D019108:Tight Junctions / Q000502:physiology
keywords: epithelial barrier; ions; lung; permeability; transport
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