Khan, A.; Koher, G.; Khan, T.; Grant, K.; Zheng, G.; Young Lee, H.; S. Vidar, W.; Morales-Shnaider, F.; Chen, J.; A. Darfour-Oduro, K.; Bhandari, R.; Zhu, X.; Wu, K.; Chiu, N.; Jia, Z.

Microplastics are pervasive environmental pollutants increasingly implicated in adverse human health effects, with emerging evidence linking MPLs exposure to elevated cardiovascular risk, including atherosclerosis. However, their specific mechanisms of action remain unknown. Human aortic endothelial cells (HAECs), located in the innermost layer of blood vessels, play a crucial role in maintaining vascular homeostasis and the development of atherosclerosis. This study demonstrates that polystyrene microplastics (80 nm MPLs) can enter HAECs through multiple pathways, including macropinocytosis, clathrin-mediated endocytosis, and caveolin-mediated endocytosis, and co-localize with mitochondria and lysosomes. MPLs exposure resulted in coordinated transcriptional, epitranscriptomic, and metabolomic reprogramming in HAECs, characterized by disruption of mitochondrial genes and an inflammatory response with activation of TNF-a; and NF-kB signaling. Integrative analysis revealed remodeling of the epitranscriptomic profile, demonstrated by an increase in 1-methyladenosine (m1A) modification along with reciprocal regulation (TRMT61A upregulation and ALKBH3 suppression) of its transcriptomic machinery, alongside other enzymes associated with 3-methylcytidine (m3C), pseudouridine (Y), 5-methylcytidine (m5C), and 7-methylguanosine (m7G) pathways. By comparing transcriptomic data from MPLs-treated HAECs with those of human atherosclerotic plaques, several common dysregulated pathways were identified, particularly those related to vascular physiological regulation and cell signaling. Metabolomic profiling further revealed significant remodeling of lipid metabolic networks associated with oxidative stress and inflammatory signaling. In summary, this study reveals that HAECs can internalize MPLs, leading to multiple disturbances in the transcriptome, epigenome, and metabolic networks, suggesting that MPLs exposure may pose a potential hazard to human cardiovascular health.