Microcystins-Loaded Aged Nanoplastics Provoke a Metabolic Shift in Human Liver Cells

Abstract

Studies concerning the toxicity of pollutant-loaded nanoplastics (NPs) toward humans are still in their infancy. Here, we evaluated the adsorption of microcystins (MCs) by pristine and aged polystyrene nanoplastics (PSNPs), prepared MCs-loaded aged PSNPS (1, 5, 10, 15, and 19 μg/mg), and systematically mapped the key molecular changes induced by aged and MCs-loaded PSNPs to human hepatoblastoma (HepG2) cells. According to the results, MC-LR adsorption is increased 2.64-fold by aging, and PSNP accumulation is detected in HepG2 cells. The cytotoxicity of the MC-LR-loaded aged PSNPs showed a positive relationship with the MC-LR amount, as the cell viability in the 19 μg/mg loading treatment (aPS-MC19) was 10.84% lower than aged PSNPs; meanwhile, more severe oxidative damage was observed. Primary approaches involved stressing the endoplasmic reticulum and reducing protein synthesis that the aged PSNPs posed for HepG2 cells, while the aggravated cytotoxicity in aPS-MC19 treatment was a combined result of the metabolic energy disorder, oxidative damage, endoplasmic reticulum stress, and downregulation of the MC-LR target protein. Our results confirm that the aged PSNPs could bring more MC-LR into the HepG2 cells, significantly interfere with biological processes, and provide new insight into deciphering the risk of NPs to humans.

Photoaged Tire Wear Particles Leading to the Oxidative Damage on Earthworms (Eisenia fetida) by Disrupting the Antioxidant Defense System: The Definitive Role of Environmental Free Radicals

“…More importantly, a few studies reported that the role of photoweathering enhanced the biotoxicity of contaminants. − For example, photoaging reduced the size of microplastics (MPs), induced the production of nanoplastics (NPs), and promoted the leaching of chemical additives, which enhanced the hepatotoxicity of zebrafish . Meanwhile, NPs exhibited an increased capacity to adsorb more polar pollutants (e.g., microcystins) through surface oxidation, thus aggravating cytotoxicity . Our recent studies have also evidenced that photoaging induced the formation of environmentally persistent free radicals (EPFRs) in TWP, which are more reactive and induce oxidative stress and inflammatory response in in vitro cells. , At present, EPFRs, defined as a substance that carries unpaired electrons stably existing in natural conditions, have been considered an emerging contaminant with serious toxicity to human and ecological health. − Overall, the photoweathering processes could influence the physicochemical characteristics (e.g., shape, size, surface chemistry, and additives) of TWP, resulting in inconsistent toxic responses by changing their interaction with organisms.…”

Micro(nano)plastics in the Human Body: Sources, Occurrences, Fates, and Health Risks

“…However, the percentage of MNPs, especially NPs, that are removed from the human body remains unclear. Due to their small sizes, NPs may be more hazardous than bigger plastic particles. , Furthermore, in vivo mammal and in vitro cell experiments showed that MNPs may cause intestinal disturbance, cardiovascular toxicity, reproductive toxicity, and acute mortality; however, their mechanisms remain unclear. − It is also unknown whether MNPs produce the same effects on the human body. No direct evidence regarding this critical issue has yet been found yet.…”