Protein-bound microplastics can disrupt brain cells and potentially cause neurotoxicity

A research team revealed that microplastics introduced into the body may bind to proteins in vivo, disrupt the function of brain cells, and act as neurotoxicants. Based on proteomics analysis, the study precisely demonstrated how microplastics bound to proteins alter biological properties in the body and cause inflammatory responses and cellular function disruptions.

The research is published in the journal Environmental Science & Technology. The work was led by Director Seongkyoon Choi of the Core Protein Resources Center and Professor Wookyung Yu of the Department of Brain Sciences at the Daegu Gyeongbuk Institute of Science & Technology (DGIST).

Although plastics are essential in modern society, many plastics leak into the environment because of low recycling rates and turn into microplastics. As microplastics enter the human body through air, water, and food, there is mounting concern that they can stay in the body and hurt various physiological functions. Specifically, microplastics easily bind to proteins in vivo because of their size and chemical properties. They are likely to induce completely different forms of biological responses than previously observed.

However, most existing research has focused on the toxicity of plastics, with limited practical studies examining the effects of microplastics bound to proteins on the human body in an in vivo environment. The research team used precise proteomics analysis to examine how microplastics bind to proteins and alter cellular functions.

The research team first treated mouse serum with microplastics to form the microplastics that absorbed proteins and then treated them with mouse brain-derived neurons and human microglia to analyze their response in vivo. The results confirmed that the microplastics that absorbed proteins disturbed various functions required for sustaining life, such as intracellular protein synthesis, RNA processing, lipid metabolism, and mass transport. These findings suggest that microplastics cause fundamental functional damage at the cellular level, beyond merely physical stimulation.

Notably, the microplastics that absorbed serum proteins demonstrated the potential to induce inflammatory gene expression, disrupt cell signaling and physiological functions, and act as neurotoxicants if they continue to build up in the body. This study is significant, suggesting that microplastics bound to proteins are more biologically hazardous than plastics. It also offers an entirely new perspective for the risk assessment of microplastics in the future.

“This study revealed that microplastics interact with proteins in vivo to acquire new biological properties and disrupt the functions of brain cells to act as neurotoxicants,” said Director Seongkyoon Choi of the Core Protein Resources Center, DGIST. “This study is expected to be a key turning point for microplastics research in the future, as it suggests a new perspective for evaluating the hazards of microplastics.”