Transient increase in lung epithelial tight junction permeability: an additional mechanism for enhancement of lung transgene expression by perfluorochemical liquids

Abstract

Intratracheal instillation of perfluorochemical (PFC) liquids enhances lung epithelial transgene expression by improved vector propulsion throughout lung airways. We now demonstrate that PFC liquids also facilitate gene transfer by increasing transepithelial permeability. Apical application of PFC liquid to well-differentiated human airway epithelial cells resulted in a transient decrease in transepithelial resistance peaking approximately 2 h after PFC liquid administration and returning to normal approximately 24 h later. The permeability change was sufficient to enhance access of apically applied 100-nm latex beads and adenoviral vectors to the basolateral side of the culture. Adenovirus-mediated gene expression was concurrently enhanced. Following intratracheal instillation of PFC liquid into mouse lungs, tight junction permeability, as assessed by electron microscopic evaluation of lanthanum deposition, was increased with peak effect between 6 h and 1 day after instillation. Importantly, alveolar-capillary permeability remained unchanged with the treatment. Administration of PFC liquid 6 h or 1 day, but not 3 days, prior to instillation of a recombinant adenovirus vector enhanced gene expression comparable to that observed with concurrent administration of PFC liquid and vector. We conclude that transient increase in epithelial permeability after PFC liquid administration contributes to the enhancement of adenovirus vector-mediated gene expression in lung epithelium.

Perfluorochemical Liquid-Adenovirus Suspensions Enhance Gene Delivery to the Distal Lung

“…Next, reagents such as EGTA that disrupt tight junctions have been shown to improve expression in the airways by exposing CAR on the basolateral surfaces of airway epithelium. Various PFC liquids have been utilized to improve expression in the distal airways of both healthy and diseased lungs [3, 6–10]. Our findings reflect at least two mechanisms thought to be involved with improved expression.…”

“…Our findings reflect at least two mechanisms thought to be involved with improved expression. First, it has been previously shown that PFC liquid facilitates transient disruption of tight junctions, increasing exposure to CARs, that are distributed throughout the A549 cell membrane [3]. Second, based on the physicochemical property of this specific PFC liquid combination (with unique kinematic viscosity, vapor pressure, and lipophilicity profiles) [14, 36], the PFC suspension fosters increased and uniformed distribution of the virus relative to saline, such that more cells are exposed to virus.…”

“…Lung surfactant acts as a barrier and surfactant proteins act as collectins to remove recombinant proteins and viruses for gene therapy [1, 2]. The distribution of the coxsackie-adenovirus receptor (CAR) on basolateral surfaces of cells has led to the proposed use of reagents that disrupt tight junctions and improve transduction of airway epithelial cells [3–5]. As an alternative approach to improve distribution, several studies have used an intratracheal pulse-chase method in the lung to deliver recombinant adenovirus (rAd) and adeno-associated virus vectors in a small volume of saline administered followed by a larger volume of perfluorochemical (PFC) liquid [3, 6–11].…”

“…The distribution of the coxsackie-adenovirus receptor (CAR) on basolateral surfaces of cells has led to the proposed use of reagents that disrupt tight junctions and improve transduction of airway epithelial cells [3–5]. As an alternative approach to improve distribution, several studies have used an intratracheal pulse-chase method in the lung to deliver recombinant adenovirus (rAd) and adeno-associated virus vectors in a small volume of saline administered followed by a larger volume of perfluorochemical (PFC) liquid [3, 6–11]. These studies have demonstrated increased total lung gene expression, distribution of gene expression, and enhanced delivery to the distal lung over saline alone.…”

Aerosol delivery of an enhanced helper-dependent adenovirus formulation to rabbit lung using an intratracheal catheter

“…Various strategies have been described, including pre-treatment with the Ca 2+ chelator EGTA [21], perfluorochemical liquid ventilant [29], and the detergents sodium caprate [30] and LPC [22]. LPC is a natural component of lung surfactant and is converted in the lung into phosphatidylcholine [31].…”