Zhao, Yuanqin, Wang, Yanxia, Zheng, Hongyu, Xu, Qian, Zhou, Kun, Liu, Huiting, Xia, Yu, Wei, Dang-Heng, Jiang, Miao, Tang, Zhi-Han, Liu, Lu-Shan, Zheng, He, and Jiang, Zhisheng
Under normal circumstances, high-density lipoprotein (HDL) is considered to have cardiovascular protective effects, but the impact of oxidized HDL (ox-HDL) on vascular endothelial function remains poorly understood. Mitochondrial function is closely related to endothelial function, and hydrogen sulfide (H₂S) is a gas with endothelial protective properties. The novel hydrogen sulfide donor AP39 can target mitochondria to release H₂S, but the combined effects of ox-HDL and AP39 on vascular endothelium are not well studied. We established a cell model of ox-HDL-induced endothelial cell damage and mitochondrial dysfunction using human umbilical vein endothelial cells (HUVECs) and conducted AP39 pretreatment. The experiments confirmed the functional damage and mitochondrial dysfunction in HUVECs caused by ox-HDL. Additionally, to further explore the role of SIRT1 in AS, we analyzed SIRT1 expression in AS carotid artery tissue. This included the analysis of differentially expressed genes from AS-related datasets, presented through volcano plots and heatmaps, with enrichment analysis of downregulated genes in KEGG pathways and GO functions. Furthermore, we evaluated the differences in SIRT1 expression in coronary arteries with varying degrees of stenosis and in early and late-stage AS carotid artery tissues, and analyzed data from SIRT1 knockout mouse models. The experimental results indicate that AP39 effectively alleviated ox-HDL-induced endothelial cell damage and mitochondrial dysfunction by upregulating SIRT1 expression. MTT and CCK-8 assays showed that ox-HDL treatment led to decreased cell viability and proliferation in HUVECs, reduced eNOS expression, and significantly increased levels of ICAM-1, IL-6, and TNF-α, along with enhanced monocyte adhesion. These findings reveal the damaging effects of ox-HDL on HUVECs. Transcriptomic data indicated that while SIRT1 expression did not significantly differ in coronary arteries with varying degrees of stenosis, it was notably downregulated in AS carotid artery tissues, especially in late-stage AS tissues. KEGG pathway enrichment analysis revealed that SIRT1 downregulated genes were associated with processes such as vascular smooth muscle contraction, while GO analysis showed that these downregulated genes were involved in muscle system processes and muscle contraction functions, further confirming SIRT1's critical role in AS pathology. In transcriptomic data from the SIRT1 knockout mouse model, elevated levels of inflammation-related proteins IL-6 and TNF-α were observed after SIRT1 knockout, along with decreased expression of the chaperone protein PGC-1α. The expression of mitochondrial-related functional proteins Nrf2 and PGC-1α was positively correlated with SIRT1 expression, while inflammation-related proteins ICAM-1, IL-6, IL-20, and TNF-α were negatively correlated with SIRT1 expression. We further discovered that ox-HDL triggered mitochondrial dysfunction, as evidenced by reduced expression of Mfn2, Nrf2, PGC1-α, UCP-1, and SIRT1, corroborating the results from the previous database analysis. Additionally, mitochondrial dysfunction was characterized by decreased mitochondrial membrane potential (MMP), increased mitochondrial ROS levels, and reduced ATP content, further impacting cellular energy metabolism and respiratory function. Subsequent experimental results showed that the addition of AP39 mitigated these adverse effects, as evidenced by decreased levels of ICAM-1, IL-6, and TNF-α, increased eNOS expression, reduced monocyte adhesion, increased mitochondrial H₂S content, and upregulated expression of SIRT1 protein associated with mitochondrial function, reduced ROS levels, and increased ATP content. Furthermore, validation experiments using the SIRT1 inhibitor EX527 confirmed that AP39 alleviated ox-HDL-induced endothelial cell damage and mitochondrial dysfunction by upregulating SIRT1 expression. Ox-HDL can induce damage and mitochondrial dysfunction in HUVECs, while AP39 inhibits ox-HDL-induced endothelial cell damage and mitochondrial dysfunction by upregulating SIRT1. • Mechanism Insight: Elucidates ox-HDL's harmful effects on endothelial cells, focusing on SIRT1 downregulation and mitochondrial dysfunction. • Mitochondrial Targeting : AP39, a mitochondria-targeted hydrogen sulfide donor, mitigates ox-HDL-induced damage by upregulating SIRT1. • Cellular and Molecular Impact: AP39 improves cell survival, reduces pro-inflammatory markers, and decreases monocyte adhesion in endothelial cells. • Mitochondrial Function Preservation: AP39 enhances mitochondrial membrane potential, reduces ROS, and increases ATP content, maintaining mitochondrial function. • Therapeutic Potential : Suggests AP39 as a therapy for atherosclerosis by targeting mitochondrial dysfunction and endothelial injury caused by ox-HDL. [ABSTRACT FROM AUTHOR]