https://doi.org/10.1007/s00392-025-02625-4
1Universitätsklinikum Bonn Medizinische Klinik und Poliklinik II Bonn, Deutschland; 2Uniklinik Bonn Experimentelle Hämatologie und Transfusionsmedizin Bonn, Deutschland; 3Kreiskrankenhaus Waldbröl GmbH Klinik für Innere Medizin, Kardiologie Waldbröl, Deutschland; 4Gemeinschaftspraxis Kardiologie Köln am Neumarkt Köln, Deutschland
Background:
Vitamin K exerts anti-oxidative properties which were proposed to be mediated by the vitamin K cycle enzyme VKORC1L1 (vitamin-K-2,3-epoxide-reductase-complex-subunit-1-like-1). Anti-oxidative mechanisms are critical for proper endothelial function and to ensure regeneration of the endothelium upon injury. Here, we investigated the role of vitamin K on endothelial cell regeneration and anti-oxidation.
Methods:
Human coronary artery endothelial cells (HCAEC) were treated with the vitamin K2 vitamer MK-7 (Menaquinone-7) to evaluate its effects on endothelial regeneration and anti-oxidative capacity. Cell viability was measured using the AlamarBlue assay, proliferation was assessed with EdU incorporation, apoptosis was evaluated via caspase 3/7 activity, and ferroptosis was determined by assessing viability following RSL3 stimulation. Lipid peroxidation was analyzed using Bodipy 581/591 staining, with detection by flow cytometry and immunofluorescence. Endothelial-to-mesenchymal transition and NF-κB/ICAM-1 signaling were assessed using qPCR and immunocytochemistry. RNA interference was applied to silence VKORC1L1 and VKORC1.
Results:
MK-7 treatment promoted a regenerative endothelial phenotype, marked by increased cell viability and proliferation and decreased apoptosis and ferroptosis. MK-7 also enhanced anti-oxidative capacity by reducing lipid peroxidation, ROS formation, endothelial-to-mesenchymal transition, and pro-inflammatory NF-κB/ICAM-1 signaling. Knockdown of VKORC1L1, but not of the canonical VKORC1, led to increased oxidative stress and inflammation. Importantly, MK-7 required VKORC1L1, but not VKORC1, to inhibit lipid peroxidation, ROS formation, and NF-κB activation. RNA sequencing revealed that VKORC1L1 silencing upregulated TNF expression. Accordingly, VKORC1L1-deficient endothelial cells showed elevated TNF secretion under pro-inflammatory conditions when compared to VKORC1-deficient or control cells. TNF secretion in VKORC1L1-silenced cells was driven by NF-κB signaling and was dependent on lipid peroxidation, which was effectively inhibited by Ferrostatin-1. Finally, blocking TNF shedding with TAPI-1 reduced ROS formation and inflammation in VKORC1L1-silenced HCAEC.
Conclusion:
Vitamin K promotes endothelial cell regeneration by mitigating lipid peroxidation, ferroptotic cell death, and TNF-mediated inflammation. These protective effects are mediated by VKORC1L1 but not the canonical vitamin K enzyme VKORC1.