Silver nanoparticles reduce the apoptosis induced by tumor necrosis factor-α

Abstract

Silver nanoparticles (AgNPs) are widely known to have anti-inflammatory properties, but the exact mechanism underlying this anti-inflammatory effect is not clearly understood. Tumor necrosis factor-α (TNFα) is a major pro-inflammatory cytokine that is expressed in the early stage of cell inflammation and induces apoptosis by several known pathways. Our study aimed to investigate the effect of AgNPs on the response of lung epithelial cells to TNFα and the molecular mechanism of this response. Lung epithelial cell line NCI-H292 cells were exposed to AgNPs (5 µg/mL) and/or TNFα (20 ng/mL) for 24 h, then cellular uptake was analyzed using flow cytometry. Our results showed that AgNPs were taken up by cells in a dose-dependent manner and that the cellular uptake ratio of AgNPs was significantly increased in the presence of TNFα. Apoptosis assays indicated that exposure to AgNPs significantly decreased the apoptotic effect of TNFα. Confocal microscopy was used to localize the tumor necrosis factor receptor 1 (TNFR1) and revealed that TNFR1 localized on the surface of cells exposed to TNFα. In contrast, TNFR1 localized inside cells exposed to both AgNPs and TNFα, with very few receptors scattered on the cell membrane. The results indicated that AgNPs reduced the cell surface TNFR1 expression level. The results suggested that the reduction of surface TNFR1 reduced cellular response to TNFα, resulting in an anti-apoptotic effect.

Antimicrobial and Cytotoxicity Effects of Synthesized Silver Nanoparticles from Punica granatum Peel Extract

“…In our previous study on AgNPs synthesized using Pimpinella anisum seeds, we also found that 12 μg of AgNPs was toxic to HCT116 cells by enhancing either apoptosis or necrosis [ 12 ]. A low concentration of AgNPs was also reported to be able to induce apoptosis [ 39 ]. The current experiments with AgNPs synthesized with Punica granatum peel extract also showed 55–62% toxicity with 12.5 μg.…”

All That Glitters Is Not Silver—A New Look at Microbiological and Medical Applications of Silver Nanoparticles

“…Potential toxicity of nanoparticles and their effect on growth, development and health were investigated in studies conducted on leukemic cell lines [ 87 ], the chicken embryo model and broiler chickens [ 34 , 35 ]. In vitro studies showed a toxic effect of AgNPs on keratinocyte cells, triggering apoptosis, while a higher percentage of necrotic monocytes was observed [ 88 ]. The use of silver, gold, copper and palladium nanoparticles at a level of <100 ppm, administered to the albumin or egg air chamber, did not adversely affect the growth, development and health of birds.…”

“…Strong inhibitory properties of AgNPs toward herpes simplex virus (HSV) have been reported [ 88 , 103 ]. That report opened the door to the use of AgNPs in the treatment of another viral infections.…”

An In Vitro Lung System to Assess the Proinflammatory Hazard of Carbon Nanotube Aerosols

“…In comparison, Mitsui-7 MWCNTs induced a statistically significant ( p < 0.05) increase in TNF-α levels 96 h post-exposure ( Figure 4 D). TNF-α levels specifically play a vital role in proinflammatory response assessment because it is expressed in the early stages of cell inflammation [ 65 ]. Therefore, it can be concluded that in a realistic occupational exposure scenario, exposure to MWCNTs does initiate cell inflammation and eventually can result in cell death.…”