Effects of dynamic compression on lentiviral transduction in an in vitro airway wall model

Abstract

Tomei AA, Choe MM, Swartz MA. Effects of dynamic compression on lentiviral transduction in an in vitro airway wall model. Am J Physiol Lung Cell Mol Physiol 294: L79-L86, 2008. First published November 16, 2007 doi:10.1152/ajplung.00062.2007.-Asthmatic patients are more susceptible to viral infection, and we asked whether dynamic strain on the airway wall (such as that associated with bronchoconstriction) would influence the rate of viral infection of the epithelial and subepithelial cells. To address this, we characterized the barrier function of a three-dimensional culture model of the bronchial airway wall mucosa, modified the culture conditions for optimization of ciliogenesis, and compared epithelial and subepithelial green fluorescent protein (GFP) transduction by a pWpts-GFP lentivirus, pseudotyped with VSV-G, under static vs. dynamic conditions. The model consisted of human lung fibroblasts, bronchial epithelial cells, and a type I collagen matrix, and after 21 days of culture at air liquid interface, it exhibited a pseudostratified epithelium comprised of basal cells, mucus-secreting cells, and ciliated columnar cells with beating cilia. Microparticle tracking revealed partial coordination of mucociliary transport among groups of cells. Slow dynamic compression of the airway wall model (15% strain at 0.1 Hz over 3 days) substantially enhanced GFP transduction of epithelial cells and underlying fibroblasts. Fibroblast-only controls showed a similar degree of transduction enhancement when undergoing dynamic strain, suggesting enhanced transport through the matrix. Tight junction loss in the epithelium after mechanical stress was observed by immunostaining. We conclude that dynamic compressive strain such as that associated with bronchoconstriction may promote transepithelial transport and enhance viral transgene delivery to epithelial and subepithelial cells. This finding has significance for asthma pathophysiology as well as for designing delivery strategies of viral gene therapies to the airways. mechanical stress; three-dimensional model; asthma; bronchoconstriction; ciliogenesis; human ASTHMA AND AIRWAY SUSCEPTIBILITY to viral infections have long been correlated clinically (2,9,16,26,36,61,62). Asthma is associated with recruitment of inflammatory cells, remodeling and thickening of the reticular basement membrane, subepithelial fibrosis, and airway smooth muscle hyperresponsiveness and hyperreactivity (reviewed in Refs. 7,17,19,21,23,25,48,70). The epithelial barrier function of asthmatic airways is often damaged (35), possibly increasing susceptibility to viral infection. Moreover, it has been shown that epithelial cells from asthmatic patients express a higher number of viral receptors on their surface (4, 62), which when activated exacerbate epithelial secretion of cytokines like granulocyte-macrophage colony-stimulating factor, interleukin (IL)-6, IL-8, IL-11, and RANTES that help maintain a persistent inflammatory state (46).Nevertheless, inflammatory mediators are only part of the story, as ...

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