A1 and A2b adenosine receptors regulate GPX4 against ferroptosis of cardiomyocytes in myocardial infarction rat model and in vitro.

AIM: The regulation of GPX4 by A1AR and A2bAR was investigated, and whether the inhibition of A1AR and A2bAR on ferroptosis of myocardial cell is related to GPX4 was also discussed. METHODS: we constructed a rat model of myocardial ischemia and reperfusion (MIR) model and hypoxia/reoxygenation (H/R) model of H9C2 cells, and MIR rats were intraperitoneally injected with A1AR and A2bAR agonists and antagonists. TTC staining, DHE, TUNEL, western blot experiments, immunohistochemistry assay were implemented to analyze the influence of A1AR and A2bAR on ferroptosis and potential role of GPX4. To further authenticate the result of non-specific agonists and antagonists, we transfected siRNA interference or overexpression vectors into cells. CCK8, flow cytometry and western blot were performed to evaluate cell proliferation and apoptosis, and the expression of GPX4 and ferroptosis-related proteins. RESULTS: The experimental results showed that reduced expression of A1AR, A2bAR and GPX4 was found after MIR. A1AR and A2bAR activation by agonists increased GPX4 expression and decreased production of lipid ROS, further inhibiting apoptosis of cardiomyocytes. In addition, we also analyzed the effect of A1AR and A2bAR on ferroptosis-related proteins. We found that expression of FIH1 protein increased and expression of ACSL4 and NOX1 proteins decreased. Consistent with results in vivo, cellular data also indicated that A1AR and A2bAR overexpression could increase proliferation ability of H9C2, and inhibit apoptosis and ROS production, upregulate GPX4 and FIH1, and downregulate ACSL4 and NOX1. CONCLUSION: A1AR and A2bAR could regulate GPX4, thereby affecting ferroptosis of cardiomyocytes in a rat model of MIR.

Protection of SAL B with H9C2 cells.

CONTEXT: Salvianolic acid B (Sal B) is regarded as a potent antidiabetic agent and has been reported to possess cardioprotective effect in vivo. OBJECTIVE: This study investigated the cardioprotective effects of Sal B on H9c2 cells injury caused by high glucose in vitro, and clarified the possible mechanisms. MATERIALS AND METHODS: Di ferent concentrations of Sal B were incubated with cells for 12 h prior being exposed to high glucose for 24 h. Cardioprotective effects of Sal B were evaluated using CCK-8 assay, ELISA, Hoechst 33258 nucleus staining, and western blot. RESULTS: Following a 24 h exposure of H9c2 to high glucose, obvious reduction was found in cell viability (45%), GSH (54.8 ± 9.4 ng/mg protein), catalase (1.22 ± 0.12 U/mg protein), and GPX level (67.9 ± 9.4 U/mg protein), which were associated with the increases of GSSG (1.99 ± 0.28 ng/mg protein) and ROS (2.00 ± 0.19 RFU/mg protein) production. High glucose also elevated IL-6 (1.8-fold), IL-1ß (1.9-fold), and TNF-α (1.6-fold) level, as well as induced cell apoptosis and NF-κB (6.1-fold) activation. However, Sal B (25 and 50 µM) elevated cell viability (28% and 44%), ameliorated oxidative stress (GSH, 1.3- and 1.6-fold; catalase, 1.9- and 2.0-fold; GPX, 1.1- and 1.4-fold; GSSG, 0.9- and 0.8-fold; ROS, 0.6- and 0.5-fold), and inflammatory response (IL-6, 0.9- and 0.7-fold; IL-1ß, 0.8- and 0.6-fold; TNF-α, 0.9- and 0.8-fold), and inhibited cell apoptosis and NF-κB (0.5- and 0.2-fold) expression. CONCLUSION: Sal B attenuated high glucose-induced injury and cytotoxicity through inhibiting inflammatory cytokine production in H9c2 cardiac cells.

Core self-evaluations mediate the associations of dispositional optimism and life satisfaction.

BACKGROUND: Positive traits, such as life satisfaction, optimism, and core self-evaluation (CSE), have garnered increasing attention from researchers and professionals. However, the trilateral relationship among them remains unclear. OBJECTIVE: This study examines the effect of dispositional optimism on life satisfaction and primarily verified the mediator role of CSEs. METHODS: Six hundred thirty college students from two general universities completed a questionnaire packet containing life orientation test-revised (LOT-R), core self-evaluations, and satisfaction with life scale. Confirmatory factor analysis (CFA) was conducted to assess the dimension of LOT-R. Bootstrap was used in structural equation modeling to analyze mediation effect. RESULTS: Results revealed that dispositional optimism and core self-evaluations were significantly correlated with life satisfaction. CFA identified the bidimensional structure of dispositional optimism. SEM indicated that core self-evaluations partially mediated the effect of dispositional optimism on life satisfaction. The final model also revealed significant paths from optimism and pessimism to life satisfaction through core-self evaluations. CONCLUSION: The findings extended prior studies and shed light on how dispositional optimism influences life satisfaction. This study provides valuable evidence on how to promote the life satisfaction of human beings in positive psychology. A further study can fully explore the relationship among them in multi-cultural follow-up studies.

Cilostazol promotes mitochondrial biogenesis in human umbilical vein endothelial cells through activating the expression of PGC-1α.

Mitochondrial dysfunction is frequently observed in vascular diseases. Cilostazol is a drug approved by the US Food and Drug Administration for the treatment of intermittent claudication. Cilostazol increases intracellular cyclic adenosine monophosphate (cAMP) levels through inhibition of type III phosphodiesterase. The effects of cilostazol in mitochondrial biogenesis in human umbilical vein endothelial cells (HUVECs) were investigated in this study. Cilostazol treated HUVECs displayed increased levels of ATP, mitochondrial DNA/nuclear DNA ratio, expressions of cytochrome B, and mitochondrial mass, suggesting an enhanced mitochondrial biogenesis induced by cilostazol. The promoted mitochondrial biogenesis could be abolished by Protein kinase A (PKA) specific inhibitor H-89, implying that PKA pathway played a critical role in increased mitochondrial biogenesis after cilostazol treatment. Indeed, expression levels of peroxisome proliferator activator receptor gamma-coactivator 1α (PGC-1α), NRF 1 and mitochondrial transcription factor A (TFAM) were significantly increased in HUVECs after incubation with cilostazol at both mRNA levels and protein levels. Importantly, knockdown of PGC-1α could abolish cilostazol-induced mitochondrial biogenesis. Enhanced expression of p-CREB and PGC-1α induced by cilostazol could be inhibited by H-89. Moreover, the increased expression of PGC-1α induced by cilostazol could be inhibited by downregulation of CREB using CREB siRNA at both mRNA and protein levels. All the results indicated that cilostazol promoted mitochondrial biogenesis through activating the expression of PGC-1α in HUVECs, which was mediated by PKA/CREB pathway.