Bioinformatics Analysis Reveals Hub Genes That May Reduce Inflammation and Complications After Cardiopulmonary Bypass.

Cardiopulmonary bypass (CPB), though indispensable in many cardiac surgery procedures, has several undesirable consequences. The aim of this study was to identify potential genes that may reduce the inflammatory response and complications after CPB. The GSE132176 dataset was selected from the Gene Expression Omnibus (GEO) database and included 10 patients with tetralogy of Fallot and 10 patients with an atrial septal defect who underwent CPB surgery. TSV files were downloaded after GEO2R processing. Protein-protein interaction analysis of common differentially expressed genes (DEGs) was performed using the Search Tool for the Retrieval of Interacting Genes. Gene modules and hub genes were visualized in the protein-protein interaction network using Cytoscape. Enrichment analysis was performed for all important DEGs, modular genes, and hub genes. A total of 72 DEGs were screened, including two functional and one hub gene module. FOS modular genes were primarily enriched in NGF-stimulated transcription, spinal cord injury, and PID AP1 pathway. The ATF3 modular gene was mainly enriched in cytomegalovirus infection and transcriptional misregulation in cancer. Hub gene modules were primarily enriched in the PID AP1 pathway, positive regulation of pri-miRNA transcription by RNA polymerase II, and the PID ATF2 pathway. FOS, JUN, ATF3, and EGR1 were the four most important hub genes; the top three hub genes were involved in the formation of AP-1 and enriched in the AP-1 pathway. Finally, we measured the expression levels of these four genes in patients undergoing CPB via qRT-PCR, and the results were consistent with those obtained in bioinformatic analysis. FOS, JUN, ATF3, and EGR1 and the AP-1 pathway may play key roles in inflammation and complications caused by CPB.

Circular RNA PVT1 silencing prevents ischemia-reperfusion injury in rat by targeting microRNA-125b and microRNA-200a.

Circular RNAs (circRNAs) are essential regulators associated with many cardiac conditions, including myocardial infarction (MI). This study aimed to explore circRNA expression during MI development in an animal model and in hypoxia/reoxygenation (H/R)-treated cardiomyocytes. Microarray and real-time quantitative PCR showed that the circRNA PVT1 (circPVT1) was expressed at high levels in MI tissues and H/R-triggered cardiomyocytes. Loss-of-function assays were utilized for examining the influence of circPVT1 on cardiac function and cardiomyocyte properties. Cardiac function was measured by echocardiography at 7 d after MI. Reduced circPVT1 expression significantly decreased MI-triggered myocardial infarct size by 60% and prevented MI-triggered reductions in fractional shortening (%FS) and ejection fraction (EF%). Results of LDH, CCK-8, EdU staining, colony formation assays, and flow cytometry showed that circPVT1 silencing restored cell viability and proliferation while decreased apoptosis. Mechanistic experiments indicated that microRNAs (miR)-125b and miR-200a associated with circPVT1. We demonstrated that circPVT1 functioned as a competitive endogenous RNA (ceRNA) to sponge both miR-125b and miR-200a. Gain-of-function assays showed that miR-125b and miR-200a upregulation partially eliminated the effects of circPVT1 on cardiomyocyte properties. In addition, we found that the previously reported p53/TRAF6, SIRT7, Keap1/Nrf2, and PDCD4 pathways were regulated by the circPVT1/miR-125b/miR-200a axis. In conclusion, our study suggests that circPVT1 protects the myocardium from MI and H/R injury by preventing miR-125b- and miR-200a-mediated apoptotic signaling.

Deficiency of Interleukin-36 Receptor Protected Cardiomyocytes from Ischemia-Reperfusion Injury in Cardiopulmonary Bypass.

BACKGROUND Interleukin-36 has been demonstrated to be involved in inflammatory responses. Inflammatory responses due to ischemia-reperfusion injury following cardiopulmonary bypass (CPB) can cause heart dysfunction or damage. MATERIAL AND METHODS The CPB models were constructed in IL-36R-/-, IL-36RN-/-, and wild-type SD rats. Ultrasonic cardiography and ELISA were used to evaluate the cardiac function and measuring myocardial biomarker levels in different groups. TUNEL assay was used to evaluate apoptosis. Western blot assays and RT-PCR were performed to measure the expression of chemokines and secondary inflammatory cytokines in the heart. Oxidative stress in tissue and cultured cells was assessed using a DCFH-DA fluorescence probe and quantification of superoxide dismutase activity. RESULTS Improved systolic function and decreased serum levels of myocardial damage biomarkers were found in IL-36R-/- rats compared to WT rats, while worse cardiac function and cardiomyocyte IR injury were observed in IL-36RN-/- rats compared to WT rats. TUNEL staining and Western blot analyses found that cardiomyocyte apoptosis and inflammation were significantly lower in the hearts of IL-36R-/- rats compared with that of WT rats. Oxidative stress was significantly lower in IL-36R-/- rats compared to WT rats. iNOS expression was significantly reduced, while eNOS expression was increased in the hearts of IL-36R-/- rats. Silencing of IL-36R expression in vitro activated SIRT1/FOXO1/p53 signaling in cardiomyocytes. CONCLUSIONS IL-36R deficiency in cardiomyocytes repressed infiltration of bone marrow-derived inflammatory cells and oxidative stress dependent on SIRT1-FOXO1 signaling, thus protecting cardiomyocytes and improving cardiac function in CPB model rats.