Published ahead of print on September 11, 2008, doi:10.1164/rccm.200801-136OC Am. J. Respir. Crit. Care Med., Volume 178, Number 12, December 2008, 1271-1281 A more recent version of this article appeared on December 15, 2008
Submitted on January 22, 2008 Rhinovirus Disrupts the Barrier Function of Polarized Airway Epithelial CellsUmadevi Sajjan1,1 Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI, United States, 2 Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA, 3 California Pacific Medical Center Research Institute, San Francisco, CA, USA; Department of Laboratory Medicine, University of California, San Francisco, CA, USA; Department of Medicine, University of Vermont, Burlington, VT, USA, 4 Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI, United States; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA * To whom correspondence should be addressed. E-mail: mhershen{at}umich.edu.
Rationale. Secondary bacterial infection following rhinovirus (RV) infection has been recognized in chronic obstructive pulmonary disease.
Objectives. We sought to understand mechanisms by which RV infection facilitates secondary bacterial infection.
Methods. Primary human airway epithelial cells grown at air-liquid interface and 16HBE14o- cells grown as polarized monolayers were infected apically with RV. Transmigration of bacteria (non-typeable Hemophilus influenzae and others) was assessed by colony counting and transmission electron microscopy. Transepithelial resistance (RT) was measured by using a voltmeter. The distribution of zona occludins (ZO)-1 was determined by immunohistochemistry and immunoblotting.
Results. Epithelial cells infected with RV showed 2-log more bound bacteria than sham-infected cultures, and bacteria were recovered from the basolateral media of RV- but not sham-infected cells. Infection of polarized airway epithelial cell cultures with RV for 24 h caused a significant decrease in RT without causing cell death or apoptosis. UV-treated RV did not decrease RT, suggesting a requirement for viral replication. Reduced RT was associated with increased paracellular permeability, as determined by flux of FITC-inulin. Neutralizing antibodies to TNF- Key words: COPD; exacerbation; Hemophilus influenzae; tight junction; ZO-1
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, IFN-
and IL-1
reversed corresponding cytokine-induced reductions in RT but not that induced by RV, indicating that the RV effect is independent of these proinflammatory cytokines. Confocal microscopy and immunoblotting revealed the loss of ZO-1 from tight junction complexes in RV-infected cells. Intranasal inoculation of mice with RV1B also caused the loss of ZO-1 from the bronchial epithelium tight junctions in vivo.
Conclusion. RV facilitates binding, translocation and persistence of bacteria by disrupting airway epithelial barrier function.