Recent progress and future directions of the research on nanoplastic-induced neurotoxicity

Abstract

Many types of plastic products, including polystyrene, have long been used in commercial and industrial applications. Microplastics and nanoplastics, plastic particles derived from these plastic products, are emerging as environmental pollutants that can pose health risks to a wide variety of living organisms, including humans. However, it is not well understood how microplastics and nanoplastics affect cellular functions and induce stress responses. Humans can be exposed to polystyrene-microplastics and polystyrene-nanoplastics through ingestion, inhalation, or skin contact. Most ingested plastics are excreted from the body, but inhaled plastics may accumulate in the lungs and can even reach the brain via the nose-to-brain route. Small-sized polystyrene-nanoplastics can enter cells by endocytosis, accumulate in the cytoplasm, and cause various cellular stresses, such as inflammation with increased pro-inflammatory cytokine production, oxidative stress with generation of reactive oxygen species, and mitochondrial dysfunction. They induce autophagy activation and autophagosome formation, but autophagic flux may be impaired due to lysosomal dysfunction. Unless permanently exposed to polystyrene-nanoplastics, they can be removed from cells by exocytosis and subsequently restore cellular function. However, neurons are very susceptible to this type of stress, thus even acute exposure can lead to neurodegeneration without recovery. This review focuses specifically on recent advances in research on polystyrene-nanoplastic-induced cytotoxicity and neurotoxicity. Furthermore, in this review, based on mechanistic studies of polystyrene-nanoplastics at the cellular level other than neurons, future directions for overcoming the negative effects of polystyrene-nanoplastics on neurons were suggested.

Intracellular Protein Adsorption Behavior and Biological Effects of Polystyrene Nanoplastics in THP-1 Cells

“…The GO and KEGG analyses showed the entire process of NPs’ cellular internalization and their behavior in the cell. After entering the cell by endocytosis, NPs accumulated in endosomes and then entered the lysosome for degradation or exited the cell directly as exosomes. , NPs could be released into the cytoplasm or other organelles by endosomal escape or lysosomal dysfunction, thereby affecting normal cellular function such as metabolism and protein processing in the endoplasmic reticulum (ER). , …”

“…A recent study also reported the absence of significant toxicity toward THP-1 cells at low doses of NPs. NPs are more harmful than MPs because the biological effect is caused by MNPs entering the cell. , Therefore, 100 nm NPs at a concentration of 100 μg/mL were chosen for subsequent experiments.…”

“…NPs are more harmful than MPs because the biological effect is caused by MNPs entering the cell. 37,38 Therefore, 100 nm NPs at a concentration of 100 μg/ mL were chosen for subsequent experiments.…”

Direct Quantification of Nanoplastics Neurotoxicity by Single‐Vesicle Electrochemistry

“…[12][13][14][15] Given that nanoplastics can directly penetrate the blood-brain barrier (BBB) and accumulate in the central nervous system (CNS), [16][17] great concerns about their potential effects on neuronal activities and brain functions and possible link to neurodegenerative diseases as well are therefore rapidly growing. [18][19] Recent studies suggest that nanoplastics could affect the basal levels of neurotransmitters in vivo [20][21] and learning/memory abilities of mice. [22] Vesicles are the smallest organelles executing neurotransmission functions by fusing with presynaptic membranes and releasing neurotransmitters into the synaptic cleft to elicit postsynaptic depolarization and action potential propagation.…”

Direct Quantification of Nanoplastics Neurotoxicity by Single‐Vesicle Electrochemistry

“…Given that nanoplastics can directly penetrate the blood–brain barrier (BBB) and accumulate in the central nervous system (CNS), [16–17] great concerns about their potential effects on neuronal activities and brain functions and possible link to neurodegenerative diseases as well are therefore rapidly growing [18–19] . Recent studies suggest that nanoplastics could affect the basal levels of neurotransmitters in vivo [20–21] and learning/memory abilities of mice [22] .…”