CTRP13 Mitigates Endothelial Cell Ferroptosis via the AMPK/KLF4 Pathway: Implications for Atherosclerosis Protection.

ABSTRACT

BACKGROUND C1q/tumor necrosis factor-related protein 13 (CTRP13) preserves endothelial function and possesses anti-oxidation activity. However, its effects on ferroptosis of human umbilical vein endothelial cells (HUVECs) remain unclear. We investigated the effects of CTRP13 on HUVEC ferroptosis induced by oxidized low-density lipoprotein (ox-LDL) and explored the underlying mechanisms of CTRP13 against ferroptosis via the AMPK/KLF4 pathway. MATERIAL AND METHODS Cell Counting Kit-8 assay was used to evaluate cell viability. Lactate dehydrogenase activity and malondialdehyde content analysis were performed to evaluate the cell membrane integrity and lipid peroxidation. Mito-Tracker, JC-1, and 2',7'-dichlorofluorescein di-acetate were used to evaluate the biological activity of mitochondria, mitochondrial membrane potential, and reactive oxygen species (ROS) in endothelial cells. The ferroptosis indicator expressions, recombinant solute carrier family 7, member 11, glutathione peroxidase 4 (GPX4), and acyl-CoA synthetase long-chain family member 4 were examined using real-time reverse transcription-polymerase chain reaction and Western blot. Immunofluorescence staining detected GPX4 location in endothelial cells. RESULTS The results demonstrate that CTRP13 (450 ng/mL) prevented HUVEC ferroptosis by inhibiting ROS overproduction and mitochondrial dysfunction, and CTRP13 accelerated antioxidant enzyme expression levels, such as heme oxygenase 1, superoxide dismutase 1, and superoxide dismutase 2, compared with the ox-LDL (100 µg/mL) group for 48 h. Additionally, CTRP13 treatment increased p-AMPK/AMPK expression by 47.65% (P<0.05) while decreasing Krüppel-like factor 4 expression by 37.43% (P<0.05) in ox-LDL-induced HUVECs and elucidated the protective effect on endothelial dysfunction from ferroptosis. CONCLUSIONS These findings provide new insights for understanding the effects and mechanism of CTRP13 on preventing endothelial cell ferroptosis.