No abstract

Cholesterol crystal- (CC-) induced endothelial cell inflammation and pyroptosis play an important role in the development of cardiovascular diseases, especially in atherosclerosis (AS). Increasing evidence suggests that cholesterol crystals are known to be a pivotal pathological marker of atherosclerotic plaque vulnerability. As a classical nonspecific anti-inflammatory drug, colchicine has been widely used in the treatment of acute gout. However, whether colchicine could alleviate CC-induced endothelial cell injury and the related mechanisms remains to be addressed. In this study, the protective effect of colchicine on human umbilical vein endothelial cells (HUVECs) was confirmed. Our results revealed that after cotreatment with colchicine and cholesterol crystals in endothelial cells, the uptake of cholesterol crystals was significantly decreased, the cell viability was obviously increased, and the release of lactate dehydrogenase (LDH) and the number of pyroptotic cells decreased significantly; then, the expression of NLRP3 inflammasome-related proteins and various inflammatory factors was also visibly suppressed; moreover, as a potent activator of NLRP3 inflammasome, the intracellular ROS level was clearly reduced, while mitochondrial membrane potential improved significantly. In addition, the expression levels of AMP-dependent kinase (AMPK) pathway-related proteins as well as various antioxidant enzymes were elevated notably in varying degrees. However, the above effects of colchicine were completely offset by the treatment of siRNA targeting AMPKα and Sirtuin1 (SIRT1). Therefore, we conclude that colchicine plays a crucial role in alleviating the intracellular inflammatory response and NLRP3 inflammation activation, attenuating the levels of cellular oxidative stress and pyroptosis in endothelial cells via regulating AMPK/SIRT1 signaling, which may be a concrete mechanism for the secondary prevention of cardiovascular diseases.

BackgroundAtherosclerosis preferentially develops in regions of disturbed flow (DF). Emerging evidence indicates that yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ), which are both effectors of the Hippo pathway, sense different blood flow patterns and regulate atherosclerotic lesions. We previously found that methotrexate (MTX) reduces in-stent neoatherosclerosis, decreases the plaque burden, and has an effect on local fluid shear stress. Here, we investigated the atheroprotective effect of MTX under DF and the mechanisms underlying these properties.MethodsHuman umbilical vein endothelial cells (HUVECs) were subjected to biomechanical stretch using a parallel-plate flow system and treated with or without MTX at therapeutically relevant concentrations. Additionally, an extravascular device was used to induce DF in the left common carotid artery of C57BL/6 mice, followed by treatment with MTX or 0.9% saline. The artery was then assessed histopathologically after 4 weeks on a Western diet.ResultsWe observed that MTX significantly inhibited DF-induced endothelial YAP/TAZ activation. Furthermore, it markedly decreased pro-inflammatory factor secretion and monocyte adhesion in HUVECs but had no effect on apoptosis. Mechanistically, AMPKa1 depletion attenuated these effects of MTX. Accordingly, MTX decreased DF-induced plaque formation, which was accompanied by YAP/TAZ downregulation in vivo.ConclusionsTaken together, we conclude that MTX exerts protective effects via the AMP-dependent kinase (AMPK)-YAP/TAZ pathway. These results provide a basis for the prevention and treatment of atherosclerosis via the inhibition of YAP/TAZ.

Hyperglycemia-induced endothelial cell senescence has been widely reported to be involved in the pathogenesis of type 2 diabetes mellitus‒accelerated atherosclerosis. Thus, understanding the underlying mechanisms and identifying potential therapeutic targets for endothelial cell senescence are valuable for attenuating atherosclerosis progression. C1q/tumor necrosis factor-related protein 9 (CTRP9), an emerging potential cardiokine, exerts a significant protective effect with respect to atherosclerosis, particularly in endothelial cells. However, the exact mechanism by which CTRP9 prevents endothelial cells from hyperglycemia-induced senescence remains unclear. This study aimed to investigate the effects of CTRP9 on hyperglycemia-induced endothelial cell senescence and atherosclerotic plaque formation in diabetic apolipoprotein E knockout (ApoE KO) mice. Human umbilical vein endothelial cells (HUVECs) were cultured in normal glucose (5.5 mM) and high glucose (40 mM) with or without recombinant human CTRP9 protein (3 μg/ml) for 48 h. Purified lentiviruses overexpressing CTRP9 (Lv-CTRP9) and control vectors containing green fluorescent protein (Lv-GFP) were injected via the tail vein into streptozotocin-induced diabetic ApoE KO mice. Results revealed that exposure of HUVECs to HG significantly increased the expression of Krüppel-like factor 4 (KLF4) and cyclin-dependent kinase inhibitor p21 (p21) and decreased that of telomerase reverse transcriptase (TERT). Treatment with recombinant human CTRP9 protein protected HUVECs from HG-induced premature senescence and dysfunction. CTRP9 promoted the phosphorylation of AMP-activated kinase (AMPK), attenuated the expression of KLF4 and p21 induced by HG, and increased the expression of TERT in HUVECs. Furthermore, in the background of AMPKα knockdown or KLF4 activation, the protective effects of CTRP9 were abolished. In-vivo experiments showed that the overexpression of CTRP9 inhibited vascular senescence and reduced atherosclerotic plaque formation in ApoE KO mice with diabetes. In conclusion, we demonstrate that KLF4 upregulation plays a crucial role in HG-induced endothelial senescence. This anti-atherosclerotic effect of CTRP9 may be partly attributed to the inhibition of HG-induced endothelial senescence through an AMPKα/KLF4-dependent mechanism, suggesting that CTRP9 could benefit further therapeutic approaches for type 2 diabetes mellitus‒accelerated atherosclerosis.