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Metabolomics and proteomics changes triggered by myeloperoxidase-oxidized low-density lipoprotein stimulation of vascular endothelial cells

par Tangeten, Cécilia
Président du jury Vermijlen, David
Promoteur Van Antwerpen, Pierre
Co-Promoteur Zouaoui Boudjeltia, Karim
Publication Non publié, 2025-12-08

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Résumé :

The present work investigates the effects of myeloperoxidase-oxidized Low-Density lipoproteins (Mox-LDLs) on the vascular endothelium. Mox-LDLs play a significant role in the development of atherosclerosis. Despite substantial research, numerous inquiries persist regarding the endothelial responses induced by Mox-LDLs and its potential ramifications in atherosclerosis. This work presents the first omics studies on endothelial responses to Mox-LDLs.Firstly, untargeted metabolomics and proteomics analyses were conducted on endothelial cells (HUVECs) exposed to Mox-LDLs. Metabolites and proteins expressing major abundance changes following Mox-LDLs treatment were highlighted. Then, a second untargeted proteomics analysis was conducted to assess the effects of shear stress on Mox-LDL-induced endothelial response in HUVECs. Thirdly, a comparative analysis of the proteomes of the two most frequently used endothelial cells models (HUVECs and immortalized EA.hy926 cells) was conducted. Finally, targeted metabolomics analyses were conducted to detect specialized pro-resolving mediators (SPMs) in HUVECs and aortic smooth muscle cells (AoSMCs). The results suggested that Mox-LDLs were internalized and degraded by HUVECs. Concurrently, Mox-LDLs induced the expression of mitochondrial respiratory chain proteins in HUVECs, thereby promoting ROS production. They also induced a response to oxidative stress, characterized by increased expression of antioxidant proteins. In the context of inflammation, Mox-LDLs exhibited a nuanced response, displaying pro-inflammatory effects and a protective effect against inflammation and oxidative stress. Mox-LDLs might affect fibrinolysis through changes in the abundance of the plasminogen activator inhibitor-1. The proteomics analyses on the effects of shear stress demonstrated that the pathways altered by Mox-LDLs in HUVECs also undergo alteration in response to shear stress. This work also underlined the distinction between HUVECs and EA.hy926 cells. HUVECs appear to be more sensitive to Mox-LDLs than EA.hy926 cells, in which changes in proteins expressions required co-stimulation with Mox-LDLs and native LDLs. Furthermore, mitochondrial activity is altered by treatment with Mox-LDLs in HUVECs but not in EA.hy926 cells. On the other hand, the vesicle trafficking and cell division pathways are specific to EA.hy926 cells stimulated by Mox-LDLs. The detection of SPMs in the supernatant of HUVECs and AoSMCs was inconclusive. However, the abundance of intermediates in SPMs biosynthesis increased following Mox-LDL treatment in HUVECs but not in AoSMCs. Metabolomics analyses have also identified a potential new biomarker of exposure to Mox-LDLs.In conclusion, this study provides a comprehensive set of proteomics and metabolomics data, indicating that Mox-LDLs markedly alter the endothelial proteome and metabolome, inducing oxidative stress and modulating inflammatory pathways. These findings establish a framework for future research, such as the identification of the receptors responsible for Mox-LDLs internalization, the confirmation of Nrf2 pathway activation or the consequences of combined effects of shear stress and Mox-LDL stimulation.