Molecular Responses in THP-1 Macrophage-Like Cells Exposed to Diverse Nanoparticles.

Tana Brzicova,Jitka Sikorova,Vlada Philimonenko,Alena Zajicova,Kristyna Vrbova,Vladimir Holan,Jiri Klema,Dominik Pinkas,Eliska Javorkova,Pavel Rossner,Jan Topinka

doi:10.3390/nano9050687

Abstract

In the body, engineered nanoparticles (NPs) may be recognized and processed by immune cells, among which macrophages play a crucial role. We evaluated the effects of selected NPs [NM-100 (TiO2), NM-110 (ZnO), NM-200 (SiO2), and NM-300 K (Ag)] on THP-1 macrophage-like cells. The cells were exposed to subcytotoxic concentrations of NPs (1–25 µg/mL) and the expression of immunologically relevant genes (VCAM1, TNFA, CXCL8, ICAM1, CD86, CD192, and IL1B) was analyzed by RT-qPCR. The expression of selected cytokines, growth factors and surface molecules was assessed by flow cytometry or ELISA. Generation of reactive oxygen species and induction of DNA breaks were also analyzed. Exposure to diverse NPs caused substantially different molecular responses. No significant effects were detected for NM-100 treatment. NM-200 induced production of IL-8, a potent attractor and activator of neutrophils, growth factors (VEGF and IGF-1) and superoxide. NM-110 triggered a proinflammatory response, characterized by the activation of transcription factor NF-κB, an enhanced production of proinflammatory cytokines (TNF-α) and chemokines (IL-8). Furthermore, the expression of cell adhesion molecules VCAM-1 and ICAM-1 and hepatocyte growth factor (HGF), as well as superoxide production and DNA breaks, were affected. NM-300 K enhanced IL-8 production and induced DNA breaks, however, it decreased the expression of chemokine receptor (CCR2) and CD86 molecule, indicating potential immunosuppressive activity. The toxicity of ZnO and Ag NPs was probably caused by their intracellular dissolution, as indicated by transmission electron microscopy imaging. The observed effects in macrophages might further influence both innate and adaptive immune responses by promoting neutrophil recruitment via IL-8 release and enhancing the adhesion and stimulation of T cells by VCAM-1 and ICAM-1 expression.

Highlights

From the perspective of the immune system, engineered nanomaterials (NMs) represent foreign objects in the body
As toxic effects of NPs are often associated with oxidative stress induction resulting in DNA damage, we focused on reactive oxygen species (ROS) generation and formation of DNA breaks
Samples of NM-100, NM-110, and NM-200 were supplied in the form of dry powders, NM-300 K was a colloidal dispersion in deionized water (85%) containing 7% stabilizing agent and 8% emulsifiers (4% Polyoxyethylene Glycerol Trioleate and 4% Polyoxyethylene Sorbitan Monolaurate (Tween 20) with a nominal silver concentration of 10% (w/w))

Summary

Introduction

From the perspective of the immune system, engineered nanomaterials (NMs) represent foreign objects in the body. As such they may be recognized and processed by immunocompetent cells, especially those involved in the innate immune response providing a rapid, nonspecific response to potential threats. Macrophages, as professional phagocytes, represent a crucial cell component of innate immunity. The differentiated THP-1 cells have been shown to represent a suitable model system for studying macrophage functions in vitro [4]. Total RNA from lysed THP-1 macrophage-like cells was obtained using NucleoSpin RNA II according to the manufacturer’s instructions. Isolated RNA was stored at −80 ◦C until use.

Methods

Results

Conclusion