Myocardial ischemia/reperfusion (I/R) injury is a major cause of various adverse cardiovascular outcomes associated with excessive mitophagy and cardiomyocyte ferroptosis. Paired-related homeobox 1 (PRRX1) is a transcriptional factor involved in cardiovascular injury. However, whether and how PRRX1 regulates excessive mitophagy and cardiomyocyte ferroptosis during myocardial I/R injury remains unclear. Oxygen-glucose deprivation and reperfusion (OGD/R)-treated AC16 cardiomyocytes and myocardial I/R-induced rats were used as in vitro and in vivo models. Our results showed that PRRX1 expression was upregulated in AC16 cells after OGD/R treatment. PRRX1 silencing mitigated OGD/R-induced excessive mitophagy by increasing the mitochondrial membrane potential, adenosine triphosphate and p62 levels, and reducing LC3 II/I level in AC16 cells. In addition, PRRX1 knockdown attenuated OGD/R-induced lactate dehydrogenase (LDH) release and cardiomyocyte ferroptosis by decreasing reactive oxygen species, Fe 2+ and acyl-CoA synthetase long-chain family member 4 (ACSL4) levels, and increasing glutathione (GSH) and glutathione peroxidase 4 (GPX4) levels. Furthermore, PRRX1 transcriptionally promoted FK506 binding protein 5 (FKBP5), and increased p38 MAPK activation in AC16 cells. FKBP5 overexpression reversed the effects of PRRX1 silencing on excessive mitophagy and cardiomyocyte ferroptosis in OGD/R-treated AC16 cells. These effects were mitigated by a p38 MAPK inhibitor. Finally, PRRX1 downregulation mitigated myocardial I/R injury by reducing heart infarction and creatine kinase-myocardial band (CK-MB) levels in rat models. These findings demonstrate that PRRX1 silencing attenuates OGD/R-induced excessive mitophagy and cardiomyocyte ferroptosis by decreasing FKBP5 expression and inactivating p38 MAPK signaling, indicating the cardioprotective potential of PRRX1 silencing in myocardial I/R injury.
Background and Aims KISS-1 is an established tumor suppressor that inhibits metastases in various malignancies. However, little is known regarding its role in esophageal squamous cell carcinoma (ESCC). The aim of the present study was to identify the possible mechanisms of KISS-1 in ESCC metastasis. Methods The expression levels of KISS-1 mRNA and protein in ESCC samples and cell lines were analyzed by qRT-PCR, IHC, and western blotting. Bisulfite sequencing PCR (BSP) and methylation-specific PCR (MSP) were used to analyze the methylation pattern of KISS-1 promoter in ESCC cells with or without 5-Aza-dC treatment. The role of KISS-1 in the progression and metastasis of ESCC was analyzed through in vitro functional assays. Results KISS-1 mRNA and protein were markedly downregulated in ESCC tissues and cell lines compared to the respective controls. Hypermethylation of KISS-1 promoter correlated to its lower expression levels in ESCC, and KISS-1 demethylation inhibited tumor progression. Ectopic KISS-1 overexpression inhibited tumor cell metastasis in vitro. In addition, KISS-1 overexpression downregulated the matrix metalloproteinase 2 and 9 (MMP2 and 9) and inhibited epithelial–mesenchymal transition (EMT). Finally, KISS-1 downregulated phosphorylated extracellular regulated protein kinase 1/2 (ERK1/2) and phosphorylated p38 mitogen-activated protein kinase (MAPK) without affecting their total expression levels in the ESCC cells. MAPK/ERK and p38 MAPK agonists reversed the suppressive effects of KISS-1. Conclusions The hypermethylation of KISS-1 promoter partly contributed to its downregulation in ESCC. KISS-1 inhibits the metastasis of ESCC cells by targeting the MMP2/9/ERK/p38 MAPK axis.
危险品化学品经营许可证（带存储）