Differential bioreactivity of neutral, cationic and anionic polystyrene nanoparticles with cells from the human alveolar compartment: robust response of alveolar type 1 epithelial cells

Abstract

BackgroundEngineered nanoparticles (NP) are being developed for inhaled drug delivery. This route is non-invasive and the major target; alveolar epithelium provides a large surface area for drug administration and absorption, without first pass metabolism. Understanding the interaction between NPs and target cells is crucial for safe and effective NP-based drug delivery. We explored the differential effect of neutral, cationic and anionic polystyrene latex NPs on the target cells of the human alveolus, using primary human alveolar macrophages (MAC) and primary human alveolar type 2 (AT2) epithelial cells and a unique human alveolar epithelial type I-like cell (TT1). We hypothesized that the bioreactivity of the NPs would relate to their surface chemistry, charge and size as well as the functional role of their interacting cells in vivo.MethodsAmine- (ANP) and carboxyl- surface modified (CNP) and unmodified (UNP) polystyrene NPs, 50 and 100 nm in diameter, were studied. Cells were exposed to 1–100 μg/ml (1.25-125 μg/cm2; 0 μg/ml control) NP for 4 and 24 h at 37 °C with or without the antioxidant, N-acetyl cysteine (NAC). Cells were assessed for cell viability, reactive oxygen species (ROS), oxidised glutathione (GSSG/GSH ratio), mitochondrial integrity, cell morphology and particle uptake (using electron microscopy and laser scanning confocal microscopy).ResultsANP-induced cell death occurred in all cell types, inducing increased oxidative stress, mitochondrial disruption and release of cytochrome C, indicating apoptotic cell death. UNP and CNP exhibited little cytotoxicity or mitochondrial damage, although they induced ROS in AT2 and MACs. Addition of NAC reduced epithelial cell ROS, but not MAC ROS, for up to 4 h. TT1 and MAC cells internalised all NP formats, whereas only a small fraction of AT2 cells internalized ANP (not UNP or CNP). TT1 cells were the most resistant to the effects of UNP and CNP.ConclusionANP induced marked oxidative damage and cell death via apoptosis in all cell types, while UNP and CNP exhibited low cytotoxicity via oxidative stress. MAC and TT1 cell models show strong particle-internalization compared to the AT2 cell model, reflecting their cell function in vivo. The 50 nm NPs induced a higher bioreactivity in epithelial cells, whereas the 100 nm NPs show a stronger effect on phagocytic cells.Electronic supplementary materialThe online version of this article (doi:10.1186/s12989-015-0091-7) contains supplementary material, which is available to authorized users.

In vitro monitoring of time and dose dependent cytotoxicity of aminated nanoparticles using Raman spectroscopy

“…The exposure of cells to toxic PS-NH 2 is known to result in ROS formation 57 . Increased ROS levels in the cell first impacts on the mitochondria and causes the mediation of cytotoxic effects and release of pro-apoptotic factors with increasing production of mitochondrial For 10 μM PS-NH 2 , which is close to the EC 50 value for AB, exposed cells are differentiated from unexposed cells due to a significant increase of the intensity of nucleic acid bands represented by positive features of loading 1 (785 and 810 cm -1 ), which can also be seen in the difference of mean spectra of exposed and unexposed cells (Figure 3).…”

Downregulation of caspase-3 alleviates Mycoplasma pneumoniae-induced apoptosis in alveolar epithelial cells

“…Alveolar epithelial cells synthesize and secrete cytokines, which are involved in lung inflammation, and are divided into type I and type II alveolar epithelial cells (20). Type I alveolar epithelial cells cover most of the surface of the alveoli and are the sites of gas exchange (21). Type II alveolar epithelial cells function to reduce alveolar surface tension and stabilize alveolar size (22).…”

Cytotoxicity-Related Bioeffects Induced by Nanoparticles: The Role of Surface Chemistry

“…In human alveolar epithelial type I-like cells (TT1) and primary human alveolar macrophages, amine-PS NPs induced the highest ROS level, followed by unmodified and carboxyl-PS NPs. In primary human alveolar type 2 (AT2) cells, however, these three kinds of decorations elicited similar levels of intracellular ROS (Ruenraroengsak and Tetley, 2015). In another study, it was found that amine-PS NPs (60 nm) elicited mitochondrial ROS production, while carboxyl-PS NPs with the same size had no impact on intracellular ROS levels .…”