METTL3-m6A methylation inhibits the proliferation and viability of type II alveolar epithelial cells in acute lung injury by enhancing the stability and translation efficiency of Pten mRNA.

BACKGROUND: The pathogenesis of acute lung injury (ALI) involves a severe inflammatory response, leading to significant morbidity and mortality. N6-methylation of adenosine (m6A), an abundant mRNA nucleotide modification, plays a crucial role in regulating mRNA metabolism and function. However, the precise impact of m6A modifications on the progression of ALI remains elusive. METHODS: ALI models were induced by either intraperitoneal injection of lipopolysaccharide (LPS) into C57BL/6 mice or the LPS-treated alveolar type II epithelial cells (AECII) in vitro. The viability and proliferation of AECII were assessed using CCK-8 and EdU assays. The whole-body plethysmography was used to record the general respiratory functions. M6A RNA methylation level of AECII after LPS insults was detected, and then the "writer" of m6A modifications was screened. Afterwards, we successfully identified the targets that underwent m6A methylation mediated by METTL3, a methyltransferase-like enzyme. Last, we evaluated the regulatory role of METTL3-medited m6A methylation at phosphatase and tensin homolog (Pten) in ALI, by assessing the proliferation, viability and inflammation of AECII. RESULTS: LPS induced marked damages in respiratory functions and cellular injuries of AECII. The m6A modification level in mRNA and the expression of METTL3, an m6A methyltransferase, exhibited a notable rise in both lung tissues of ALI mice and cultured AECII cells subjected to LPS treatment. METTL3 knockdown or inhibition improved the viability and proliferation of LPS-treated AECII, and also reduced the m6A modification level. In addition, the stability and translation of Pten mRNA were enhanced by METTL3-mediated m6A modification, and over-expression of PTEN reversed the protective effect of METTL3 knockdown in the LPS-treated AECII. CONCLUSIONS: The progression of ALI can be attributed to the elevated levels of METTL3 in AECII, as it promotes the stability and translation of Pten mRNA through m6A modification. This suggests that targeting METTL3 could offer a novel approach for treating ALI.

POLR1D silencing suppresses lung cancer cells proliferation and migration via inhibition of PI3K-Akt pathway.

AIM: The most common type of cancer that leads to death worldwide is lung cancer. Despite significant surgery and chemotherapy improvements, lung cancer patient's survival rate is still poor. The RNA polymerase I subunit D (POLR1D) gene can induce various cancers. A current study reported that POLR1D plays a vital role in cancer prognosis. However, its biological function in the development of lung cancer remains unclear. METHODS: Reverse transcription PCR (RT-PCR) measured the relative POLR1D protein expression level in lung cancer cell lines. Lung cancer cell proliferation, migration, and invasion were analyzed by performing cell counting kit-8 (CCK-8), and transwell. The phosphatidylinositol 3-kinase/serine-threonine kinase (PI3K/AKT) signaling pathway-related protein expressions were examined by Western blotting assay. RESULTS: POLR1D protein expression was elevated in lung cancer. Lung cancer cell loss-of-function tests showed that POLR1D silencing could attenuate cell viability both in SK-MES-1 and in H2170 cells. Furthermore, silencing POLR1D inhibited SK-MES-1 and H2170 cells proliferation, migration, and invasion. Moreover, SK-MES-1 and H2170 cells' migration and invasion capacity were potentially suppressed by the knockdown of POLR1D. The progression of multiple cancers has been implicated in the PI3K/AKT pathway. Here, we observed that POLR1D silencing suppressed lung cancer progression by inhibition of the PI3K-Akt pathway. CONCLUSIONS: The study speculated that POLR1D might provide a new potential therapeutic possibility for treating lung cancer patients via targeting PI3K/AKT.

Local intramyocardial delivery of bioglass with alginate hydrogels for post-infarct myocardial regeneration.

Heart failure (HF) is a common and serious manifestation after myocardial infarction (MI). Despite their clinical importance, current treatments for MI still have several limitations. Revascularization has been proven to have positive effects on MI-induced damage. Currently biomaterial-based angiogenesis strategies represent potential candidates for MI treatment. Bioglass (BG) is a commercially available family of bioactive glasses. BG has angiogenic properties and thus might be an attractive alternative for MI treatments. Here, we loaded BG in sodium alginate (BGSA), locally injected it into peri-infarct myocardial tissue and examined its suitability for inducing cardiac angiogenesis and eventually improving cardiac function following MI. Cardiac function was evaluated via echocardiography. Infarct morphometry, angiogenesis, apoptosis and angiogenic protein expression were all analysed 4 weeks after BGSA injection. Compared with the control treatment, BGSA was sufficient to prompt angiogenesis, suppress apoptosis, up-regulate the expression of angiogenic proteins, attenuate infarct size, preserve wall thickness and eventually improve cardiac function. Our results demonstrate the feasibility and effectiveness of BGSA in myocardial regeneration via angiogenesis, suggesting that BGSA is a potential therapeutic strategy for post-infarct myocardial regeneration.

Pericardial fluid levels of growth differentiation factor 15 in patients with or without coronary artery disease: a prospective study.

BACKGROUND: Growth differentiation factor 15 (GDF15) has already been reported as a novel efficient biomarker in patients with coronary artery diseases (CAD). However, very little is demonstrated about the potential impact of pericardial fluid GDF-15 accumulation on CAD. The aim of this study was to evaluate pericardial fluid and plasma GDF15 levels in patients with ischemic heart disease. METHODS: In this study, 42 consecutive patients (21 patients with significant CAD; 21 patients without CAD) undergoing open heart surgery were recruited in this study. Pericardial fluid were obtained at the time of surgery, and GDF15 levels in the samples were measured by enzyme-linked immunosorbent assay. Plasma glucose, creatinine, CK-MB, cTnI and N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurements were performed. RESULTS: The plasma GDF15 levels were markedly higher than the pericardial fluid levels both in the CAD group and non-CAD group (1,174.0±148.7 vs. 677.8±77.2 pg/mL, P<0.01; 925.8±127.4 vs. 617.4±76.2 pg/mL, P<0.01). The levels of pericardial fluid GDF15, was not statistically different between the CAD and non-CAD groups (P>0.05). An obvious correlation was observed between plasma and pericardial fluid GDF15 concentration both in the CAD group and non-CAD group (R=0.53, P<0.01; R=0.54, P<0.01). An obvious positive correlation was found between pericardial fluid GDF15 and plasma creatinine levels in CAD patients but not in non-CAD patients (R=0.65, P<0.01). In the CAD group, an obvious correlation was also observed between pericardial fluid GDF15 levels and NT-ProBNP (R=0.63, P<0.01), while no relationship was found in non-CAD group. There was a positive correlation between pericardial fluid GDF15 and LVEF in non-CAD group but not in CAD group patients (R=-0.44, P<0.05). CONCLUSIONS: Our study first revealed an association between pericardial fluid GDF15 and baseline characteristics. Pericardial fluid GDF15 levels are associated with cardiac and kidney function in patients with coronary artery disease and may be a valuable marker for assessing CAD severity and predicting its complications.

Elastic 3D-Printed Hybrid Polymeric Scaffold Improves Cardiac Remodeling after Myocardial Infarction.

Myocardial remodeling, including ventricular dilation and wall thinning, is an important pathological process caused by myocardial infarction (MI). To intervene in this pathological process, a new type of cardiac scaffold composed of a thermoset (poly-[glycerol sebacate], PGS) and a thermoplastic (poly-[ε-caprolactone], PCL) is directly printed by employing fused deposition modeling 3D-printing technology. The PGS-PCL scaffold possesses stacked construction with regular crisscrossed filaments and interconnected micropores and exhibits superior mechanical properties. In vitro studies demonstrate favorable biodegradability and biocompatibility of the PGS-PCL scaffold. When implanted onto the infarcted myocardium, this scaffold improves and preserves heart function. Furthermore, the scaffold improves several vital aspects of myocardial remodeling. On the morphological level, the scaffold reduces ventricular wall thinning and attenuated infarct size, and on the cellular level, it enhances vascular density and increases M2 macrophage infiltration, which might further contribute to the mitigated myocardial apoptosis rate. Moreover, the flexible PGS-PCL scaffold can be tailored to any desired shape, showing promise for annular-shaped restraint device application and meeting the demands for minimal invasive operation. Overall, this study demonstrates the therapeutic effects and versatile applications of a novel 3D-printed, biodegradable and biocompatible cardiac scaffold, which represents a promising strategy for improving myocardial remodeling after MI.

Human Neonatal Thymus Mesenchymal Stem Cells Promote Neovascularization and Cardiac Regeneration.

Newborns with critical congenital heart disease are at significant risk of developing heart failure later in life. Because treatment options for end-stage heart disease in children are limited, regenerative therapies for these patients would be of significant benefit. During neonatal cardiac surgery, a portion of the thymus is removed and discarded. This discarded thymus tissue is a good source of MSCs that we have previously shown to be proangiogenic and to promote cardiac function in an in vitro model of heart tissue. The purpose of this study was to further evaluate the cardiac regenerative and protective properties of neonatal thymus (nt) MSCs. We found that ntMSCs expressed and secreted the proangiogenic and cardiac regenerative morphogen sonic hedgehog (Shh) in vitro more than patient-matched bone-derived MSCs. We also found that organoid culture of ntMSCs stimulated Shh expression. We then determined that ntMSCs were cytoprotective of neonatal rat cardiomyocytes exposed to H2O2. Finally, in a rat left coronary ligation model, we found that scaffoldless cell sheet made of ntMSCs applied to the LV epicardium immediately after left coronary ligation improved LV function, increased vascular density, decreased scar size, and decreased cardiomyocyte death four weeks after infarction. We conclude that ntMSCs have cardiac regenerative properties and warrant further consideration as a cell therapy for congenital heart disease patients with heart failure.

17ß-estradiol promotes recovery after myocardial infarction by enhancing homing and angiogenic capacity of bone marrow-derived endothelial progenitor cells through ERα-SDF-1/CXCR4 crosstalking.

17ß-estradiol (E2) has been shown to mediate endothelial progenitor cells (EPCs) to repair infarcted myocardium. Both estrogen receptor α (ERα) and stromal derived factor-1 (SDF-1)/CXCR4 signaling pathways may play a critical role in regulating homing and angiogenesis of EPCs in this process. However, the interaction between ERα and SDF-1/CXCR4 signaling pathways remains unclear. In response to E2, the expression of SDF-1 and CXCR4 in EPCs from ovariectomized BALB/C mice was obviously up-regulated, in addition, the migration and tube formation of EPCs in vitro were also significantly enhanced. However, ERα antagonist (MMP) and CXCR4 inhibitor (AMD3100) significantly decreased the migration and tube length of EPCs, even if mediated by E2. The combined treatment of MMP and AMD3100 exerted more inhibitory effects on migration and tube formation of EPCs induced by E2. In in vivo studies, ovariectomized mice were induced acute myocardial infarction (AMI), and divided into four groups (n = 6): non-preconditioned EPCs (3 × 106) group, E2-preconditioned EPCs group, MMP + AMD3100 preconditioned EPCs group, and EPCs pretreated with E2 + MMP + AMD3100 group. E2 group displayed a greater number of homing EPCs, increased capillary density in infarcted myocardium, decreased left ventricular (LV) fibrosis. Nevertheless, these effects of E2 were almost completely blocked by the combined treatment of MMP and AMD3100. E2 can produce cardiovascular protective effects in AMI setting by enhancing homing and angiogenic capacity of EPCs through ERα and CXCR4 signaling pathways, which means that ERα and CXCR4 pathways are effective targets for the development of treatment strategies for AMI.

Plasma levels of matrix metalloproteinase 9 in patients undergoing off-pump coronary artery bypass grafting.

BACKGROUND: Matrix metalloproteinase 9 (MMP9) has recently emerged as a risk predictor in patients with cardiovascular diseases. However, little is known about the significance of increased plasma MMP9 in patients with perioperative myocardial injury. We aimed to investigate the role of MMP9 in the occurrence of myocardial injury during off-pump coronary artery bypass grafting (OPCAB). METHODS: A total of 34 consecutive patients with coronary artery diseases (CAD) were recruited in this prospective, observational study. All patients were operated for OPCAB surgery. Serial blood samples were collected preoperatively and 12 hours after surgery. MMP9, together with cardiac troponin I (cTnI), creatinine kinase myocardial b fraction (CK-MB), C-reactive protein (CRP), and N-terminal pro B-type natriuretic peptide (NT-proBNP) levels in plasma were measured at each time-point. RESULTS: MMP9 levels increased significantly at 12 hours after surgery, attaining nearly 2 times the baseline levels (P=0.0001). There was a significant correlation between preoperative (pre-OP) circulating levels of MMP9 and the left ventricular ejection fraction (LVEF) (r=0.48; P=0.004) as well as European System for Cardiac Operative Risk Evaluation (EuroSCORE) II (r=0.43; P=0.012). Patients were in New York Heart Association (NYHA) functional class III or IV heart failure showed a significantly higher MMP9 levels (1,348.0±337.2 vs. 630.4±93.0 ng/L, P=0.012) as compared to the patients in NYHA functional class I and II. No significant correlation was observed between MMP9 and age (P=0.612), serum creatinine (P=0.185), CRP (P=0.207), NT-proBNP (P=0.058). A significant correlation was observed in these data between the post-OP MMP9 and cTnI (r=0.35; P=0.003). CONCLUSIONS: Our study first established a connection between MMP9 and OPCAB procedure, suggesting that MMP9 could be a novel biomarker for identifying perioperative myocardial injury in patients undergoing OPCAB.

Off-pump coronary artery bypass surgery outcomes in patients with ischaemic left ventricular systolic dysfunction with or without detected viable myocardium.

OBJECTIVES: The prognostic value of myocardial viability before coronary bypass grafting remains controversial. The present study evaluated the effects of off-pump coronary artery bypass (OPCAB) grafting on patients with coronary artery disease (CAD) with or without viable myocardium (VM) preoperatively detected via nuclear imaging. METHODS: A total of 115 consecutive patients with 3-vessel disease and impaired left ventricular ejection fraction (LVEF ≤ 45%) who underwent OPCAB grafting were recruited in this prospective study. The patients were divided into 2 groups based on myocardial viability, the non-viable myocardium (NVM, 55 patients) and VM (60 patients) groups. Positron emission tomography and radionuclide imaging examination were applied to evaluate the myocardium viability. A Kaplan-Meier analysis was conducted to evaluate the 1-year survival rate. RESULTS: The preoperative data were similar between groups. An improvement in the LVEF was observed in both groups 12 months after OPCAB grafting (P < 0.05). A binary logistic regression revealed that NVM was an independent predictor of a 5% improvement in LVEF at 6 months (P = 0.012). The rate of main adverse cardiovascular and cerebrovascular events (MACCEs) rate at 1 year was similar between the 2 groups (P = 0.06). At 1 year, the death rates were 14.5% in the NVM group and 5% in the VM group (P = 0.17). A Cox regression analysis revealed that NVM and age were independent predictors of mortality [the hazard ratio for death associated with NVM and age were 1.62, 95% confidence interval (CI) = 1.16-2.89, P = 0.036 and 1.05, 95% CI = 0.98-1.12, P =0.025, respectively]. CONCLUSIONS: The MACCEs and mortality rates of the NVM group were higher than those of the VM group. However, OPCAB surgery improved LVEF, regardless of myocardium status. Therefore, the assessment of myocardial viability might not be the sole deciding factor in decision-making process regarding OPCAB surgery.

Plasma levels of growth differentiation factor-15 are associated with myocardial injury in patients undergoing off-pump coronary artery bypass grafting.

Growth differentiation factor-15 (GDF-15) has recently emerged as a risk predictor in patients with cardiovascular diseases. We therefore aimed to investigate the role of GDF-15 in the occurrence of cardiac injury during off-pump coronary artery bypass grafting (OPCAB). 55 consecutive patients with coronary artery diseases were recruited in this prospective, observational study. All patients were operated for OPCAB surgery. Serial blood samples were collected preoperatively, 12 hours and 36 hours after surgery. GDF-15, together with C-reactive protein, cardiac troponin I, creatine kinase MB and N-terminal pro B-type natriuretic peptide levels in plasma were measured at each time-point. GDF-15 levels increased significantly at 12 hours after surgery, attaining nearly 2.5 times the baseline levels (p < 0.001). Postoperative GDF-15 levels correlated positively with cTnI (p = 0.003) and EuroSCORE II (p = 0.013). According to the ROC curves, postoperative plasma GDF-15 was found to be the best biomarker to predict perioperative cardiac injury, compared with cTnI, CK-MB and EuroSCORE II. Circulating GDF-15 is a promising novel biomarker for identifying perioperative myocardial injury in patients undergoing OPCAB.

Tissue-engineered mitral valve chordae tendineae: Biomechanical and biological characterization of decellularized porcine chordae.

Chordae tendineae are essential for maintaining mitral valve function. Chordae replacement is one of the valve repair procedures commonly used to treat mitral valve regurgitation. But current chordae alternatives (polytetrafluoroethylene, ePTFE) do not have the elastic and self-regenerative properties. Moreover, the ePTFE sutures sometimes fail due to degeneration, calcification and rupture. Tissue-engineered chordae tendineae may overcome these problems. The utility of xenogeneic chordae for tissue-engineered chordae tendineae has not yet been adequately explored. In this study, polyelectrolyte multilayers (PEM) film modified decellularized porcine mitral valve chordae (PEM-DPC) were developed to explore tissue-engineered chordae tendineae as neochordae substitutes. Fresh porcine mitral chordae were decellularized and reserved the major elastic fiber and collagen components. Decellularized chordae with a PEM film were produced with chitosan-heparin by a lay-by-lay technique. Mesenchymal stem cells and vascular endothelial cells could grow well on the surface of the PEM-DPC. The superior biomechanical properties of PEM-DPC were proved with good flexibility and strength both in vitro and in vivo. PEM-DPC can be developed for potential alternative mitral valve chordae graft.