Abstract
The health risks of exposure to ‘eco-friendly’ biodegradable plastics of anthropogenic origin and their effects on the gastrointestinal tract are largely unknown. Here we demonstrate that the enzymatic hydrolysis of polylactic acid microplastics generated nanoplastic particles by competing for triglyceride-degrading lipase during gastrointestinal processes. Nanoparticle oligomers were formed by hydrophobically driven self-aggregation. In a mouse model, polylactic acid oligomers and their nanoparticles bioaccumulated in the liver, intestine and brain. Hydrolysed oligomers caused intestinal damage and acute inflammation. A large-scale pharmacophore model revealed that oligomers interacted with matrix metallopeptidase 12. Mechanistically, high binding affinity (Kd = 13.3 μmol l−1) of oligomers to the catalytic zinc-ion finger domain led to matrix metallopeptidase 12 inactivation, which might mediate the adverse bowel inflammatory effects after exposure to polylactic acid oligomers. Biodegradable plastics are considered to be a solution to address environmental plastic pollution. Thus, understanding the gastrointestinal fates and toxicities of bioplastics will provide insights into potential health risks.
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Data availability
All data supporting the findings of this study are available within this article and its Supplementary Information. Source data are provided with this paper.
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Acknowledgements
This work was primarily supported by the National Key R&D Program (nos. 2022YFC3702600 and 2022YFC3702601), the Singapore Ministry of Education Academic Research Fund Tier 1 (04MNP000567C120), the Ministry of Science and Technology of China (2022YF3701101), Startup Grant of Fudan University (no. JIH 1829010Y), Education Department of Anhui Province for Excellent Young Scientist (2022AH030076) and Second Tibetan Plateau Scientific Expedition and Research program (2019QZKK0682). We also acknowledge Y. Deng from Jinan University and Y. Zhan from Nanjing University for professional discussion and H. Yang, Y. Hua and S. Li from Research Center for Eco-Environmental Sciences for help with the NTA experiment.
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M.W. and M.F. conceived and designed the study. Y.H., J.C. and M.F. supervised the study. M.W., Q.L. and J.L. performed the in vivo experiments and data analysis. C.S. and J.Y. conducted the mass spectrometry experiments. M.W. and Y.X. performed the MD simulations. M.W., Q.L., L.J. and Q.L. contributed to the biochemistry and characterization experiments. H.C. contributed to the synthesis experiments. S.L.C. and C.H. performed HepG2 cellular uptake experiments. M.W., Y.H., J.C. and M.F. wrote the manuscript with input from all the authors. All the authors discussed the results.
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Wang, M., Li, Q., Shi, C. et al. Oligomer nanoparticle release from polylactic acid plastics catalysed by gut enzymes triggers acute inflammation. Nat. Nanotechnol. 18, 403–411 (2023). https://doi.org/10.1038/s41565-023-01329-y
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DOI: https://doi.org/10.1038/s41565-023-01329-y