Paeonol improves angiotensin II-induced cardiac hypertrophy by suppressing ferroptosis.

The aim of this study was to investigate the protective effect of paeonol (pae) on an angiotensin II (AngII)-induced cardiac hypertrophy mouse model. First, AngII mouse models were constructed and randomly grouped into the control (con), AngII, and AngII + Pae groups. Compared with that in the blank group, the surface area of myocardial cells in the AngII group increased significantly. In contrast to that in the AngII group, the cardiomyocyte surface area in the Pae group was significantly reduced. Ultrasound results showed that the myocardial function of mice in the AngII group was decreased compared with that in the Con group, while the myocardial function of mice in the Pae treatment was significantly improved. Moreover, the Fe2+ and lipid peroxide levels of primary cardiomyocytes were significantly increased after treatment with AngII and were significantly decreased after the addition of Pae. Compared with those in the Con group, cristae were reduced and the outer membrane was lost in the myocardial tissues of the AngII group, and myocardial MDA, ROS, and Fe2+ levels were increased. However, myocardial damage was significantly alleviated after Pae treatment, and myocardial MDA, ROS, and Fe2+ levels were reduced. Moreover, in myocardial tissue, AngII reduced the protein levels of xCT and GPX4, while the levels of both xCT and GPX4 were increased after Pae treatment. In conclusion, Pae protected the hearts of AngII mice by upregulating the protein expression of xCT and GPX4 and resisting AngII-induced ferroptosis in cardiomyocytes.

Activating autophagy and ferroptosis of 3­Chloropropane­1,2­diol induces injury of human umbilical vein endothelial cells via AMPK/mTOR/ULK1.

3­Chloropropane­1,2­diol (3­MCPD) is an internationally recognized food pollutant. 3­MCPD has reproductive, renal and neurotoxic properties. However, whether 3­MCPD induces human umbilical vein endothelial cell (HUVEC) injury has not been previously reported. In the present study, HUVECs were treated using 2 µg/ml 3­MCPD for 24 h at 37˚C. The effects of 3­MCPD on HUVEC proliferation and cell cycle arrest, death and senescence were then assessed using Cell Counting Kit­8 (CCK­8), flow cytometry and ß­galactosidase staining, respectively. Whether 3­MCPD induced ferroptosis was evaluated using JC­1 and FerroOrange staining and transmission electron microscopy. A small interfering RNA targeting AMPK was used to assess whether 3­MCPD promoted ferroptosis via AMPK signaling. The results demonstrated that 3­MCPD inhibited HUVEC proliferation in a dose­dependent manner and induced cell cycle arrest. Furthermore, 3­MCPD promoted senescence in HUVECs with elevated DNA damage and cell death. The CCK­8 results demonstrated that ferroptosis and autophagy inhibitors significantly reversed cell death caused by 3­MCPD. Moreover, 3­MCPD increased mitochondrial membrane potential, which indicated that 3­MCPD contributed to mitochondrial dysfunction. 3­MCPD also markedly increased intracellular Fe2+ levels and lipid peroxidation in HUVECs. The present study assessed the underlying mechanism by which 3­MCPD activated autophagy and ferroptosis in HUVECs. The data demonstrated that 3­MCPD significantly increased phosphorylation levels of AMPK and unc­51 like autophagy activating kinase (ULK1) but significantly decreased phosphorylation of mTOR in HUVECs. Furthermore, silencing of AMPK significantly reversed the increase in autophagy, lipid peroxidation and Fe2+ induced by 3­MCPD. In conclusion, 3­MCPD demonstrated a significant damaging effect on HUVECs via induction of autophagy and ferroptosis; such effects may be mediated by AMPK/mTOR/ULK1 signaling. To the best of our knowledge, the present study was the first to demonstrate the mechanism of 3­MCPD­induced vascular endothelial cell injury and lays a molecular foundation for the prevention of 3­MCPD­related vascular diseases.

Decreased miR-208 induced ischemia myocardial and reperfusion injury by targeting p21.

Aberrant expression of miR-208 was previously reported in cardiomyocytes after cardiac ischemia reperfusion (CIR) injury. However, the underlying mechanism has never been elucidated. In the current study, the relative level of miR-208 was determined in the hearts of CIR injury mice models using real time PCR. The effect of miR-208 on cardiomyocytes apoptosis was determined by Hoechst staining and annexin V-PI staining. Meanwhile, caspase3 activity was explored using an assay kit. To identify left ventricular fraction and relative wall thickness, the two-dimensional echocardiography was applied. Dual luciferase assay was applied to determine the target gene of miR-208. Compared with normal control, the level of miR-208 was significantly reduced in the hearts of CIR injury mouse models. Further studies revealed that reduction of miR-208 contributed to reactive oxygen species (ROS) production in the cardiomyocytes. We also found that inhibition of miR-208 prompted cardiomyocyte apoptosis. More importantly, the phosphorylation level of Akt and p38 was enhanced in primary cardiomyocytes transfected with miR-208 inhibitor, indicating a potential stress-response after CIR injury in primary cardiomyocytes. Dual luciferase assay and western blot analysis showed that transfection with miR-208 markedly suppressed the protein expression of p21, suggesting p21 was a target gene of miR-208. To conclude, we showed that reduced miR-208 level enhanced cardiomyocyte apoptosis mainly by targeting p21.