Nanoparticle translocation across mouse alveolar epithelial cell monolayers: Species-specific mechanisms

Studies of polystyrene nanoparticle (PNP) trafficking across mouse alveolar epithelial cell monolayers (MAECM) show apical-to-basolateral flux of 20 and 120 nm amidine-modified PNP is ~ 65 times faster than that of 20 and 100 nm carboxylate-modified PNP, respectively. Calcium chelation with EGTA has little effect on amidine-modified PNP flux, but increases carboxylate-modified PNP flux ~ 50-fold. PNP flux is unaffected by methyl-β-cyclodextrin, while ~ 70% decrease in amidine- (but not carboxylate-) modified PNP flux occurs across chlorpromazine- or dynasore-treated MAECM. Confocal microscopy reveals intracellular amidine- and carboxylate-modified PNP and association of amidine- (but not carboxylate-) modified PNP with clathrin heavy chain. These data indicate (1) amidine-modified PNP translocate across MAECM primarily via clathrin-mediated endocytosis and (2) physicochemical properties (e.g., surface charge) determine PNP interactions with mouse alveolar epithelium. Uptake/trafficking of nanoparticles into/across epithelial barriers is dependent on both nanoparticle physicochemical properties and (based on comparison with our prior results) specific epithelial cell type.From the Clinical EditorIn this study of polystyrene nanoparticle trafficking across mouse alveolar epithelial cell monolayers, the authors determined that uptake/trafficking of nanoparticles into/across epithelial barriers is dependent on both nanoparticle physicochemical properties and the specific type of epithelial cells.

Amidine-modified PNP translocation across MAECM occurs via clathrin-mediated endocytosis.