The oxidized phospholipid PGPC impairs endothelial function by promoting endothelial cell ferroptosis via FABP3.

Ferroptosis is a novel cell death mechanism that is mediated by iron-dependent lipid peroxidation. It may be involved in atherosclerosis development. Products of phospholipid oxidation play a key role in atherosclerosis. 1-palmitoyl-2-glutaroyl-sn-glycero-3-phosphocholine (PGPC) is a phospholipid oxidation product present in atherosclerotic lesions. It remains unclear whether PGPC causes atherosclerosis by inducing endothelial cell ferroptosis. In this study, human umbilical vein endothelial cells (HUVECs) were treated with PGPC. Intracellular levels of ferrous iron, lipid peroxidation, superoxide anions (O2•-), and glutathione were detected, and expression of fatty acid binding protein-3 (FABP3), glutathione peroxidase 4 (GPX4), and CD36 were measured. Additionally, the mitochondrial membrane potential (MMP) was determined. Aortas from C57BL6 mice were isolated for vasodilation testing. Results showed that PGPC increased ferrous iron levels, the production of lipid peroxidation and O2•-, and FABP3 expression. However, PGPC inhibited the expression of GPX4 and glutathione production and destroyed normal MMP. These effects were also blocked by ferrostatin-1, an inhibitor of ferroptosis. FABP3 silencing significantly reversed the effect of PGPC. Furthermore, PGPC stimulated CD36 expression. Conversely, CD36 silencing reversed the effects of PGPC, including PGPC-induced FABP3 expression. Importantly, E06, a direct inhibitor of the oxidized 1-palmitoyl-2-arachidonoyl-phosphatidylcholine IgM natural antibody, inhibited the effects of PGPC. Finally, PGPC impaired endothelium-dependent vasodilation, ferrostatin-1 or FABP3 inhibitors inhibited this impairment. Our data demonstrate that PGPC impairs endothelial function by inducing endothelial cell ferroptosis through the CD36 receptor to increase FABP3 expression. Our findings provide new insights into the mechanisms of atherosclerosis and a therapeutic target for atherosclerosis.

Spermidine-enhanced autophagic flux improves cardiac dysfunction following myocardial infarction by targeting the AMPK/mTOR signalling pathway.

BACKGROUND AND PURPOSE: Spermidine, a natural polyamine, is abundant in mammalian cells and is involved in cell growth, proliferation, and regeneration. Recently, oral spermidine supplements were cardioprotective in age-related cardiac dysfunction, through enhancing autophagic flux. However, the effect of spermidine on myocardial injury and cardiac dysfunction following myocardial infarction (MI) remains unknown. EXPERIMENTAL APPROACH: We determined the effects of spermidine in a model of MI, Sprague-Dawley rats with permanent ligation of the left anterior descending artery, and in cultured neonatal rat cardiomyocytes (NRCs) exposed to angiotensin II (Ang II). Cardiac function in vivo was assessed with echocardiography. In vivo and in vitro studies used histological and immunohistochemical techniques, along with western blots. KEY RESULTS: Spermidine improved cardiomyocyte viability and decreased cell necrosis in NRCs treated with angiotensin II. In rats post-MI, spermidine reduced infarct size, improved cardiac function, and attenuated myocardial hypertrophy. Spermidine also suppressed the oxidative damage and inflammatory cytokines induced by MI. Moreover, spermidine enhanced autophagic flux and decreased apoptosis both in vitro and in vivo. The protective effects of spermidine on cardiomyocyte apoptosis and cardiac dysfunction were abolished by the autophagy inhibitor chloroquine, indicating that spermidine exerted cardioprotective effects at least partly through promoting autophagic flux, by activating the AMPK/mTOR signalling pathway. CONCLUSIONS AND IMPLICATIONS: Our findings suggest that spermidine improved MI-induced cardiac dysfunction by promoting AMPK/mTOR-mediated autophagic flux.

[High glucose promotes vascular smooth muscle cell calcification by activating WNT signaling pathway].

OBJECTIVE: To investigate whether high glucose-induced vascular calcification is associated with WNT signaling pathway. METHODS: An in vitro model of human vascular smooth muscle cell (VSMC) calcification was induced by exposure of the cells to high glucose. The expressions of WNT signal molecules and bone-related proteins including Cbfa1, Osx, OCN and BMP2 were analyzed with qRT-PCR, and the cell calcification was assessed by alizarin red staining. The effect of Dkk1, a WNT signaling inhibitor, on high glucose-induced cell calcification was tested with alizarin red staining and calcium content analysis. RESULTS: High glucose activated WNT signaling pathway in human VSMCs by up-regulating the expressions of WNT signal molecules including Wnt3a, Wnt7a, Fzd4 and Wisp1 mRNA by 1.86, 1.68, 2.1, and 2.3 folds, respectively, and by promoting the phosphorylation of ß-catenin (2.70∓0.22, P<0.05), a key mediator of WNT signaling pathway. Inhibition of WNT signaling pathway by Dkk1 attenuated high glucose-induced VSMC calcification and down-regulated the expression of bone-related proteins Cbfa1, Osx, OCN, and BMP2 by (51∓9)%, (58∓11)%, (56∓10)%, and (62∓10)% (P<0.01). CONCLUSION: WNT signaling pathway is involved in high glucose-induced VSMC calcification.

[Recent advances of research on warming therapy].

Therapeutic method is an important component of traditional Chinese medicine theory. Research on warming therapy focuses on pharmacology at present. Studying the feature of nerve-body fluid-metabolism-function in cold syndrome is of importance for illustrating the nature of warming therapy and elucidating the function of medication. This review presents the research and development of warming therapy in order to provide enlightenment for the research of therapeutic method from the aspects of traditional Chinese medicine and western medicine.